WO2019150215A1 - Techniques for vertical fet gate length control - Google Patents
Techniques for vertical fet gate length control Download PDFInfo
- Publication number
- WO2019150215A1 WO2019150215A1 PCT/IB2019/050422 IB2019050422W WO2019150215A1 WO 2019150215 A1 WO2019150215 A1 WO 2019150215A1 IB 2019050422 W IB2019050422 W IB 2019050422W WO 2019150215 A1 WO2019150215 A1 WO 2019150215A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- spacers
- polymer
- fins
- brush material
- cladding layer
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 68
- 238000002789 length control Methods 0.000 title abstract description 5
- 125000006850 spacer group Chemical group 0.000 claims abstract description 192
- 229920000642 polymer Polymers 0.000 claims abstract description 158
- 238000005253 cladding Methods 0.000 claims abstract description 62
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 238000000059 patterning Methods 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims description 135
- 239000010410 layer Substances 0.000 claims description 81
- 239000002356 single layer Substances 0.000 claims description 26
- 239000004020 conductor Substances 0.000 claims description 17
- 238000005538 encapsulation Methods 0.000 claims description 16
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 15
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 11
- 239000002184 metal Substances 0.000 claims description 11
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 150000004767 nitrides Chemical class 0.000 claims description 9
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 claims description 8
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 8
- 229910052710 silicon Inorganic materials 0.000 claims description 8
- 238000000151 deposition Methods 0.000 claims description 7
- 239000004205 dimethyl polysiloxane Substances 0.000 claims description 7
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 7
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 6
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims description 6
- 230000005669 field effect Effects 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 claims description 6
- OQPDWFJSZHWILH-UHFFFAOYSA-N [Al].[Al].[Al].[Ti] Chemical compound [Al].[Al].[Al].[Ti] OQPDWFJSZHWILH-UHFFFAOYSA-N 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 5
- 229910021324 titanium aluminide Inorganic materials 0.000 claims description 5
- WVYWICLMDOOCFB-UHFFFAOYSA-N 4-methyl-2-pentanol Chemical compound CC(C)CC(C)O WVYWICLMDOOCFB-UHFFFAOYSA-N 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- RVSGESPTHDDNTH-UHFFFAOYSA-N alumane;tantalum Chemical compound [AlH3].[Ta] RVSGESPTHDDNTH-UHFFFAOYSA-N 0.000 claims description 4
- UQZIWOQVLUASCR-UHFFFAOYSA-N alumane;titanium Chemical compound [AlH3].[Ti] UQZIWOQVLUASCR-UHFFFAOYSA-N 0.000 claims description 4
- 238000004380 ashing Methods 0.000 claims description 4
- LLHKCFNBLRBOGN-UHFFFAOYSA-N propylene glycol methyl ether acetate Chemical compound COCC(C)OC(C)=O LLHKCFNBLRBOGN-UHFFFAOYSA-N 0.000 claims description 4
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 4
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 3
- 239000004793 Polystyrene Substances 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- 239000008096 xylene Substances 0.000 claims description 3
- 229910000951 Aluminide Inorganic materials 0.000 claims description 2
- ZILJFRYKLPPLTO-UHFFFAOYSA-N [C].[B].[Si] Chemical compound [C].[B].[Si] ZILJFRYKLPPLTO-UHFFFAOYSA-N 0.000 claims description 2
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910000449 hafnium oxide Inorganic materials 0.000 claims description 2
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 claims description 2
- -1 polydimethylsiloxane Polymers 0.000 claims description 2
- 229920002223 polystyrene Polymers 0.000 claims description 2
- 229910052715 tantalum Inorganic materials 0.000 claims description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 239000010937 tungsten Substances 0.000 claims description 2
- 239000002674 ointment Substances 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 28
- 230000008569 process Effects 0.000 description 28
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 23
- 239000012212 insulator Substances 0.000 description 12
- 238000001020 plasma etching Methods 0.000 description 9
- 238000005530 etching Methods 0.000 description 8
- 229920000620 organic polymer Polymers 0.000 description 8
- 235000012239 silicon dioxide Nutrition 0.000 description 8
- 239000000377 silicon dioxide Substances 0.000 description 8
- 229910052814 silicon oxide Inorganic materials 0.000 description 7
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 6
- 238000005137 deposition process Methods 0.000 description 6
- 239000002019 doping agent Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000005229 chemical vapour deposition Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000000231 atomic layer deposition Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052732 germanium Inorganic materials 0.000 description 4
- 238000005468 ion implantation Methods 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 125000000524 functional group Chemical group 0.000 description 3
- 238000005240 physical vapour deposition Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000011066 ex-situ storage Methods 0.000 description 2
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 229920005684 linear copolymer Polymers 0.000 description 2
- 238000001459 lithography Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- AUEPDNOBDJYBBK-UHFFFAOYSA-N [Si].[C-]#[O+] Chemical compound [Si].[C-]#[O+] AUEPDNOBDJYBBK-UHFFFAOYSA-N 0.000 description 1
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66666—Vertical transistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/31058—After-treatment of organic layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31127—Etching organic layers
- H01L21/31133—Etching organic layers by chemical means
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/401—Multistep manufacturing processes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
- H01L29/423—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
- H01L29/42312—Gate electrodes for field effect devices
- H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42372—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out
- H01L29/42376—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out characterised by the length or the sectional shape
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/6653—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using the removal of at least part of spacer, e.g. disposable spacer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66545—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/6656—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using multiple spacer layers, e.g. multiple sidewall spacers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/7827—Vertical transistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
- H01L29/78642—Vertical transistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31127—Etching organic layers
- H01L21/31133—Etching organic layers by chemical means
- H01L21/31138—Etching organic layers by chemical means by dry-etching
Definitions
- the present invention relates to vertical field-effect transistor (VFET) devices, and more particularly, to techniques for VFET gate length control using a material-based patterning method with self-limiting thickness control.
- VFET vertical field-effect transistor
- VFETs vertical field effect transistors
- CMOS complementary metal oxide semiconductor
- VFETs vertical field effect transistors
- the gate length (Lg) of a VFET is primarily controlled by two etch processes.
- the gate conductor is deposited conformally around the fin followed by (1) an OPL planarization and etch back process (to expose a top of the fin for the top source and drain), and (2) a wet gate metal etch.
- the gate length is mostly defined at this stage, but subsequent high-k dry etch and OPL ashing may also have very fine effects on the Lg as well.
- Such an etch-controlled gate length (Lg) is, however, subject to a large variation including within wafer, wafer-to-wafer, batch -to-batch, tool dependency, and pattern density (i.e., etch micro-loading) effect.
- the present invention provides a method of forming a vertical field-effect transistor (VFET) device, the method comprising the steps of: patterning fins in a substrate; forming bottom source and drains at a base of the fins; forming bottom spacers on the bottom source and drains; forming first polymer spacers alongside opposite sidewalls of the fins, wherein the first polymer spacers comprise a monolayer of a first polymer brush material; forming second polymer spacers on the bottom source and drains offset from the fins by the first polymer spacers, wherein the second polymer spacers comprise a monolayer of a second polymer brush material that is un-grafted to the first polymer brush material; removing the first polymer spacers selective to the second polymer spacers creating a gap between the second polymer spacers and the fins; reflowing the second polymer spacers to close the gap; forming a cladding layer alongside the opposite sidewalls of
- the present invention provides VFET device, comprising: fins patterned in a substrate; bottom source and drains at a base of the fins; bottom spacers disposed on the bottom source and drains; a cladding layer disposed alongside opposite sidewalls of the fins; gates disposed along the opposite sidewalls of the fins in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by a distance between the bottom spacers and the cladding layer; top spacers disposed above the cladding layer; and top source and drains disposed above the top spacers.
- the present invention provides techniques for vertical field-effect transistor (VFET) gate length control using a material-based patterning method with self-limiting thickness control.
- a method of forming a VFET device includes: patterning fins in a substrate; forming bottom source and drains at a base of the fins; forming bottom spacers on the bottom source and drains; forming first polymer spacers alongside opposite sidewalls of the fins, wherein the first polymer spacers include a monolayer of a first polymer brush material; forming second polymer spacers on the bottom source and drains offset from the fins by the first polymer spacers, wherein the second polymer spacers include a monolayer of a second polymer brush material that is un-grafted to the first polymer brush material; removing the first polymer spacers selective to the second polymer spacers creating a gap between the second polymer spacers and the fins; reflowing the second polymer spacers
- a VFET device in another aspect of the invention, includes: fins patterned in a substrate; bottom source and drains at a base of the fins; bottom spacers disposed on the bottom source and drains; a cladding layer disposed alongside opposite sidewalls of the fins; gates disposed along the opposite sidewalls of the fins in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by a distance between the bottom spacers and the cladding layer; top spacers disposed above the cladding layer; and top source and drains disposed above the top spacers.
- FIG. 1 is a schematic diagram illustrating a polymer brush according to an embodiment of the present invention
- FIG. 2 is a diagram illustrating an exemplary methodology for grafting a monolayer of a polymer brush onto a surface according to an embodiment of the present invention
- FIG. 3 is a cross-sectional diagram illustrating fin hardmasks having been used to pattern at least one fin in a substrate, bottom source and drains having been formed in the substrate at the base of the fins, and bottom spacers having been formed on the bottom source and drains according to an embodiment of the present invention
- FIG. 4 is a cross-sectional diagram illustrating a first polymer brush material having been coated onto the fins and bottom spacers according to an embodiment of the present invention
- FIG. 5 is a cross-sectional diagram illustrating a monolayer of the organic polymer brush material having been grafted to the fin hardmasks, the fins, and the bottom spacers according to an embodiment of the present invention
- FIG. 6 is a cross-sectional diagram illustrating un-grafted (unreacted) portions of first polymer brush material having been rinsed away leaving behind the monolayer of the organic polymer brush material grafted to the fin hardmasks, the fins, and the bottom spacers according to an embodiment of the present invention
- FIG. 7 is a cross-sectional diagram illustrating the monolayer of the organic polymer brush material having been patterned into first polymer spacers alongside opposite sidewalls of the fins according to an embodiment of the present invention
- FIG. 8 is a cross-sectional diagram illustrating an Si-containing brush material having been grafted to the exposed silicon oxide/nitride surfaces (i.e., of the fin hardmasks and bottom spacers) forming second polymer spacers according to an embodiment of the present invention
- FIG. 9 is a cross-sectional diagram illustrating the first polymer spacers having been removed creating a gap in between the sidewalls of the fins and the second polymer spacers according to an embodiment of the present invention.
- FIG. 10 is a cross-sectional diagram illustrating a reflow of the second polymer spacers having been used to close the gap according to an embodiment of the present invention
- FIG. 11 is a cross-sectional diagram illustrating a cladding layer having been deposited over the second polymer spacers and fin hardmasks/fins according to an embodiment of the present invention
- FIG. 12 is a cross-sectional diagram illustrating a directional etch having been used to remove the cladding layer from horizontal surfaces including from the top surface of the second polymer spacers in between the fins according to an embodiment of the present invention
- FIG. 13 is a cross-sectional diagram illustrating the fins having been buried in a dielectric fill material according to an embodiment of the present invention
- FIG. 14 is a cross-sectional diagram illustrating the dielectric fill material having been polished down to the fin hardmasks according to an embodiment of the present invention
- FIG. 15 is a cross-sectional diagram illustrating the dielectric fill material as well as the second polymer spacers having been removed selective to the bottom spacers, cladding layer and the fins according to an embodiment of the present invention
- FIG. 16 is a cross-sectional diagram illustrating a gate dielectric having been deposited onto the fin hardmasks, exposed sidewalls of the fins, bottom spacers and cladding layer according to an embodiment of the present invention
- FIG. 17 is a cross-sectional diagram illustrating a gate conductor having been deposited onto the gate dielectric according to an embodiment of the present invention.
- FIG. 18 is a cross-sectional diagram illustrating a directional etch having been used to pattern the gate conductor according to an embodiment of the present invention.
- FIG. 19 is a cross-sectional diagram illustrating the fin hardmasks/fins, the cladding layer and the gates having been buried in a dielectric fill material according to an embodiment of the present invention
- FIG. 20 is a cross-sectional diagram illustrating an etch having been used to recess the dielectric fill material according to an embodiment of the present invention
- FIG. 21 is a cross-sectional diagram illustrating an etch having been used to recess the gate dielectric according to an embodiment of the present invention.
- FIG. 22 is a cross-sectional diagram illustrating the dielectric fill material having been removed according to an embodiment of the present invention.
- FIG. 23 is a cross-sectional diagram illustrating an encapsulation layer having been deposited over the fin hardmasks/fins, the cladding layer and the gates according to an embodiment of the present invention
- FIG. 24 is a cross-sectional diagram illustrating an insulator having been deposited over the encapsulation layer, burying the fins according to an embodiment of the present invention
- FIG. 25 is a cross-sectional diagram illustrating an etch having been performed to recess the insulator below the tops of the fins according to an embodiment of the present invention
- FIG. 26 is a cross-sectional diagram illustrating an etch having been performed to recess the encapsulation layer and the cladding layer and to remove the fin hardmasks from the tops of the fins according to an embodiment of the present invention
- FIG. 27 is a cross-sectional diagram illustrating top spacers having been formed above the cladding layer according to an embodiment of the present invention.
- FIG. 28 is a cross-sectional diagram illustrating top source and drains having been formed at the tops of the fins above the top spacers according to an embodiment of the present invention
- FIG. 29 is a top-down image of fins patterned in a Si substrate according to an embodiment of the present invention.
- FIG. 30 is a top-down image of a monolayer of an (e.g., organic) brush material having been formed over the fins according to an embodiment of the present invention
- FIG. 31 is a top-down image of the organic brush material having been patterned according to an embodiment of the present invention
- FIG. 32 is a three-dimensional image of the organic brush material having been grafted to the fins and fin hardmasks (above bottom spacers) and etched according to an embodiment of the present invention
- FIG. 33 is a three-dimensional image of a monolayer of a second (e.g., Si-containing) brush material having been grafted to the fin hardmasks and bottom spacers according to an embodiment of the present invention.
- a second (e.g., Si-containing) brush material having been grafted to the fin hardmasks and bottom spacers according to an embodiment of the present invention.
- VFET vertical field-effect transistor
- Lg gate length
- a polymer brush is a linear copolymer of one or more components plus a grafting functional group at one end. See, for example, Mansky et al., “Controlling Polymer-Surface Interactions with Random Copolymer Brushes,” Science, vol. 275, pgs. 1458-1460 (March 1997) (hereinafter“Mansky”).
- FIG. 1 depicts schematically a polymer brush 100.
- Polymer brush 100 is a linear copolymer having components A and B, as well as a grafting functional group C.
- only one monolayer of the polymer brush can be grafted onto a surface, thereby providing a self-limiting thickness on the surface. See, for example, FIG. 2.
- the polymer brush is cast onto a substrate (in this case a silicon (Si) substrate for illustrative purposes only).
- a substrate in this case a silicon (Si) substrate for illustrative purposes only.
- an anneal is used to graft a monolayer of the polymer brush (“Brush grafted”) onto the substrate.
- the anneal is performed at a temperature of from about 25 9 C to about 300 9 C, and ranges therebetween, wherein the lower bound is determined by the functional group, and the upper bound is determined by the polymer decomposition.
- the un-grafted portion of the polymer brush is then rinsed away, leaving behind the monolayer of the polymer brush grafted to the substrate. See step 206.
- Suitable solvents for the rinse include, but are not limited to propylene glycol monomethyl ether acetate (PGMEA), toluene, benzene, xylene, tetrahydrofuran (THF), methyl isobutyl carbinol (MIBC), gamma-butyrolactone (GBA), and combinations thereof.
- PMEA propylene glycol monomethyl ether acetate
- THF tetrahydrofuran
- MIBC methyl isobutyl carbinol
- GSA gamma-butyrolactone
- the thickness of the polymer brush can be controlled based on the annealing time (duration) but will reach a self-limiting (saturated) thickness determined by the molecular weight of the brush. See, for example, FIG. 1 of Mansky.
- a first type of polymer brush material employed will be an organic brush material such as polystyrene (PS):
- Si brush material such as polydimethylsiloxane (PDMS):
- the process begins with at least one fin 306 being patterned in a substrate 302.
- the substrate 302 is a bulk semiconductor wafer, such as a bulk silicon (Si), bulk germanium (Ge), bulk silicon germanium (SiGe) and/or bulk lll-V semiconductor wafer.
- substrate 302 can be a semiconductor-on-insulator (SOI) wafer.
- SOI wafer includes a SOI layer separated from an underlying substrate by a buried insulator. When the buried insulator is an oxide it is referred to herein as a buried oxide or BOX.
- the SOI layer can include any suitable semiconductor, such as Si, Ge, SiGe, and/or a lll-V semiconductor.
- a patterned fin hardmask 304 is formed on the substrate marking the footprint and location of the fins 306.
- Suitable hardmask materials include, but are not limited to, nitride hardmask materials such as silicon nitride (SiN), silicon boron carbon nitride (SiBCN), silicon oxycarbon nitride (SiOCN), and/or silicon carbon nitride (SiCN).
- the fin hardmasks 304 are then used to etch the fins 306 in the substrate 302. According to an exemplary embodiment, the fin etch is carried out using a directional etching process such as reactive ion etching (RIE). As shown in FIG. 3, the fins 306, as patterned, extend partway through the substrate 302.
- RIE reactive ion etching
- bottom source and drains 308 are formed in the substrate at the base of the fins 306.
- bottom source and drains 308 are formed using an ion implantation process to introduce dopants into the substrate 302 at the base of the fins 306.
- Suitable n-type dopants include, but are not limited to, phosphorous (P) and/or arsenic (As).
- Suitable p-type dopants include, but are not limited to, boron (B). Ion implantation is, however, only one techniques contemplated herein for forming the bottom source and drains 308.
- an in-situ (i.e., during growth) or ex-situ (e.g., via ion implantation) doped epitaxial source and drain material e.g., epitaxial Si, Ge and/or SiGe
- epitaxial source and drain material e.g., epitaxial Si, Ge and/or SiGe
- Bottom spacers 310 are then formed on the bottom source and drains 308. See FIG. 3.
- the bottom spacers 310 are formed using a directional deposition process whereby a spacer material is deposited onto the bottom source and drains 308 with a greater amount of the material being deposited on the horizontal surfaces, as compared to the vertical surfaces. In that case, a greater thickness of the spacer material will be deposited on top of the bottom source and drains 308 than, for example, along the sidewalls of the fins 306.
- the timing of the etch needed to remove the spacer material from the vertical surfaces will leave the bottom spacers 310 shown in FIG.
- a high density plasma (HDP) chemical vapor deposition (CVD) or physical vapor deposition (PVD) process can be used for directional film deposition, and an isotropic etch can be used to remove the (thinner) spacer material deposited onto the vertical surfaces.
- Suitable materials for the bottom spacers 310 include, but are not limited to, oxide spacer materials such as silicon dioxide (S1O2) and/or silicon carbon oxide (SiCO), and nitride spacer materials such as SiN, SiBCN, SiOCN and/or SiCN.
- a first polymer brush material 402 is then coated onto the fins 306 and bottom spacers 310.
- the first polymer brush material 402 is an organic brush material such as polystyrene.
- An organic polymer brush material does not have a preference for silicon oxide versus nitride, and thus the first polymer brush material 402 will graft to the fin hardmasks 304, the fins 306, and the bottom spacers 310.
- a conformal, self-limiting thickness layer 502 of the organic polymer brush material is formed grafted to the fin hardmasks 304, the fins 306, and the bottom spacers 310.
- the un-grafted (unreacted) portion of first polymer brush material 402 is then rinsed away (see above) leaving behind the conformal layer 502 of the organic polymer brush material grafted to the fin hardmasks 304, the fins 306, and the bottom spacers 310.
- a directional etching process such as RIE is then used to pattern the layer 502 of the organic polymer brush material into (first) polymer spacers 702 alongside opposite sidewalls of the fins 306.
- this spacer etch serves to remove the layer 502 of the organic polymer brush material from horizontal surfaces, including from the tops of the fin hardmasks 304 and the bottom spacers 310.
- the polymer spacers 702 have a thickness of from about 2.5 nanometers (nm) to about 3.5 nm, and ranges therebetween.
- the second polymer brush material is an Si-containing brush material such as PDMS with a -COOH end-functional group (i.e., PDMS provides the SiOx and the end-group provides the grafting selectivity) which grafts selectively to the exposed silicon oxide/nitride surfaces (i.e., of the fin hardmasks 304 and bottom spacers 310) over the polymer surfaces (i.e., of the polymer spacers 702) to form (second) polymer spacers 802.
- Si-containing brush material such as PDMS with a -COOH end-functional group (i.e., PDMS provides the SiOx and the end-group provides the grafting selectivity) which grafts selectively to the exposed silicon oxide/nitride surfaces (i.e., of the fin hardmasks 304 and bottom spacers 310) over the polymer surfaces (i.e., of the polymer spacers 702) to form (second) polymer spacers 802.
- polymer spacers 802 are formed by the same process described above, whereby the Si-containing brush material is coated onto the fin hardmasks 304 and the bottom spacers 310 using, e.g., a casting process such as spin-coating. It is notable that, while the Si-containing brush material coated on the fin hardmasks 304 can be selectively removed (see below), it is possible to reduce or eliminate the Si-containing brush material on the fin hardmasks 304 by controlling the spin-coating thickness. As shown in FIG. 8, the polymer spacers 802 are offset from the fins 306 by the polymer spacers 702.
- the end- functional group of the Si-containing brush material has a preference for the exposed silicon oxide/nitride surfaces, and thus will graft to the fin hardmasks 304 and bottom spacers 310 following an anneal (suitable conditions were provided above).
- the un-grafted (unreacted) portion of the Si-containing brush material is then rinsed away leaving behind the polymer spacers 802 grafted to the fin hardmasks 304 and bottom spacers 310.
- the polymer spacers 802 are formed having a height h of from about 15 nanometers (nm) to about 20 nm, and ranges therebetween.
- the polymer spacers 802 do not, however, graft to the polymer spacers 702.
- the polymer spacers 702 can then be easily removed (e.g., via ashing) while oxidizing the polymer spacers 802 into silicon oxide-like materials. Removal of the polymer spacers 702 leaves a precise gap g in between the sidewalls of the fins 306 and the polymer spacers 802 equivalent to the thickness of the monolayer of the first polymer brush material used to form the polymer spacers 702 (see above).
- a reflow of the polymer spacers 802 is then used to close the gap g. As shown in FIG 10, this reflow also results in densification of the polymer spacers 802. According to an exemplary embodiment, the reflow is performed by annealing the polymer spacers 802 at a temperature of from about 500 9 C to about 1000 9 C, and ranges therebetween.
- the reflow and densification will change the volume/height of the polymer spacers 802 (see dashed boxes 1002 indicating the dimensions of polymer spacers 802 prior to reflow).
- dashed boxes 1002 indicating the dimensions of polymer spacers 802 prior to reflow.
- the volume change/height difference of the polymer spacers 802 after reflow can be easily estimated.
- the dimensions of the polymer spacers 802 after reflow can be calculated as follows:
- h is the height of the polymer spacers 802 prior to reflow (see, e.g., FIG. 8 - described above), h new is the height of the polymer spacers 802 after reflow, D fin is the width of the fins 306, and t bmsh is the thickness of the first polymer brush material used to form the polymer spacers 702, wherein t hmsh is a thickness in the horizontal direction, whereas h and h new are height measurements in the vertical direction.
- Pitch is the distance from a given point on one fin 306 to the same given point on an adjacent fin 306.
- a cladding layer 1102 is then conformally deposited over the polymer spacers 802 and fin hardmasks 304/fins 306.
- suitable conformal deposition processes include, but are not limited to, chemical vapor deposition (CVD) and atomic layer deposition (ALD).
- Suitable cladding materials include, but are not limited to, SiN, SiBCN, SiOCN, and/or SiCN.
- the cladding layer 1102 is formed having a thickness of from about 5 nm to about 8 nm, and ranges therebetween.
- a directional etch is then used to remove the cladding layer 1102 from horizontal surfaces including from the top surface of the polymer spacers 802 in between the fins 306.
- suitable directional etching processes include, but are not limited to, reactive ion etching (RIE).
- RIE reactive ion etching
- a nitride-selective RIE can be employed with the (e.g., PDMS) polymer spacers 802 acting as an etch stop.
- the fins 306 are then buried in a dielectric fill material 1302.
- suitable dielectric fill materials include, but are not limited to, S1O2 and/or SiCO.
- the dielectric fill material 1302 enables use of a process, such as chemical-mechanical polishing (CMP), to provide a flat, planar surface for further processing. See, for example, FIG. 14 which illustrates the dielectric fill material 1302 having been polished down to the fin hardmasks 304 using, e.g., CMP.
- the dielectric fill material 1302 as well as the polymer spacers 802 are then removed selective to the bottom spacers 310, cladding layer 1102 and the fins 306.
- the dielectric fill material 1302 and the polymer spacers 802 are both oxide materials (e.g., SiCfe and oxidized PDMS, respectively) which can be removed using a wet etch with hydrofluoric acid (HF) and/or a chemical oxide removal (COR) process.
- HF hydrofluoric acid
- COR chemical oxide removal
- Gates i.e., a gate dielectric and gate conductor are next formed alongside the fins 306.
- the amount of the fin 306 sidewalls that is exposed i.e., based on the distance between the bottom spacers 310 and the cladding layer 1102 (alongside which the gates will be formed) is set by removal of the polymer spacers 802 (e.g., a monolayer of the Si-containing brush material). As shown in FIG.15, this will be used to set the gate length (Lg).
- the gate materials are often deposited over the entire fin and then etched back which sets the gate length.
- such an etch-based process is subject to a large variation including within wafer, wafer-to- wafer, batch-to-batch, tool dependency, and pattern density (i.e., etch microloading) effect.
- a gate dielectric 1602 is first conformally deposited onto the fin hardmasks 304, exposed sidewalls of the fins 306, bottom spacers 310 and cladding layer 1102. As shown in FIG. 16, according to an exemplary embodiment, the gate dielectric 1602 is deposited to a thickness of from about 0.5 nm to about 2 nm, and ranges therebetween. A gate conductor 1702 is then conformally deposited onto the gate dielectric 1602. As shown in FIG. 17, according to an exemplary embodiment, the gate conductor 1702 is deposited to a thickness of from about 4 nm to about 6 nm, and ranges therebetween. Suitable conformal deposition processes include, but are not limited to ALD.
- the gate dielectric 1602 is a high-k gate dielectric and the gate conductor 1702 is a workfunction setting metal.
- the particular workfunction setting metal employed can vary depending on whether an NFET (n-type workfunction setting metal) or PFET (p-type workfunction setting metal) is being formed.
- Suitable n-type workfunction setting metals include, but are not limited to, titanium nitride (TiN), tantalum nitride (TaN) and/or aluminum (Al)-containing alloys such as titanium aluminide (TiAI), titanium aluminum nitride (TiAIN), titanium aluminum carbide (TiAIC), tantalum aluminide (TaAI), tantalum aluminum nitride (TaAIN), and/or tantalum aluminum carbide (TaAIC).
- Suitable p-type workfunction setting metals include, but are not limited to, TiN, TaN, and tungsten (W).
- TiN and TaN are relatively thick (e.g., greater than about 2 nanometers (nm)) when used as p-type workfunction metals.
- very thin TiN or TaN layers e.g., less than about 2 nm
- Al-containing alloys in n-type workfunction stacks may also be used beneath Al-containing alloys in n-type workfunction stacks to improve electrical properties such as gate leakage currents.
- gate leakage currents there is some overlap in the exemplary n- and p-type workfunction metals given above.
- Suitable high-k gate dielectrics include, but are not limited to, HfCte and/or lanthanum oxide (La203).
- the opening at the tops of the fins 306 might get pinched off before the gate conductor 1702 fully fills the space between the fins 306, resulting in voids in the gate conductor 1702 below the cladding layer 1102. These voids will however be removed via a directional etch performed in the next step.
- a directional etch (e.g., RIE) is used to pattern the gate conductor 1702.
- This directional etch is shadowed by the cladding layer 1102.
- the gate conductor 1702 alongside the fin 306 sidewalls below the cladding layer 1102 remains following the etch.
- the gate conductor 1702 exposed between the fins 306 is removed, and along with it any of the voids that may have formed during the gate conductor 1702 deposition.
- this directional etch defines the gate length (Lg) below the cladding layer 1102.
- the amount of exposed fin 306 sidewall is set by removal of the polymer spacers 802, i.e., the monolayer of the Si-containing brush material.
- the Lg is defined by the monolayer thickness of the Si- containing brush material which is consistent from one device to another.
- the gate dielectric 1602 is then recessed. However, the recessed height of the gate dielectric 1602 is not critical since the Lg has already been defined.
- the fin hardmasks 304/fins 306, the cladding layer 1102 and the gates are buried in a fill material 1902. As shown in FIG. 19, as shown in FIG. 20, the as-deposited fill material 1902 can be etched back to provide a flat planar surface.
- Suitable dielectric fill materials include, but are not limited to, organic planarizing (OPL) materials
- An etch is then used to recess the fill material 1902. As shown in FIG. 20, standard lithography and etching techniques can be employed for the recess etch. This recess of the fill material 1902 will set the height of the (to be recessed - see below) gate dielectric 1602. However, as provided above, the recessed height of the gate dielectric 1602 is not critical since the Lg has already been defined. According to an exemplary embodiment, the fill material 2002 is recessed below the tops of the fins 306, but still overlaps the cladding layer 1102. See FIG. 20. [0042] An etch is then used to recess the gate dielectric 1602. As shown in FIG.
- the gate dielectric is recessed to the height of the recessed fill material 1902.
- the fin hardmasks 304 and the cladding layer 1102 at the tops of the fins 306 are now exposed.
- the remaining fill material 1902 is then removed, e.g., by ashing. See FIG. 22
- An encapsulation layer 2302 is then conformally deposited over the fin hardmasks 304/fins 306, the cladding layer 1102 and the gates. See FIG. 23.
- Suitable materials for the encapsulation layer 2302 include, but are not limited to, SiN, SiBCN, SiOCN, and/or SiCN.
- Suitable conformal deposition processes include, but are not limited to, ALD.
- the encapsulation layer is formed having a thickness of from about 2 nm to about 3 nm, and ranges therebetween. The encapsulation layer 2302 will protect the gates during the subsequent processing steps.
- an insulator 2402 is then deposited over the encapsulation layer 2302, burying the fins 306.
- the as-deposited insulator 2402 can be polished using a process such as CMP to provide a flat planar surface.
- Suitable insulators include, but are not limited to, S1O2 and/or SiCO.
- An etch is then performed to recess the insulator 2402 below the tops of the fins 306. See FIG. 25.
- the insulator 2402 when the insulator 2402 is formed from an oxide material (e.g., S1O2 and/or SiCO), an oxide-selective etching process such as an oxide-selective RIE can be used for the recess etch.
- This recess etch of the insulator 2402 exposes the encapsulation layer 2302, the cladding layer 1102 and the fin hardmasks 304 at the tops of the fins 306.
- An etch is then performed to recess the encapsulation layer 2302 and the cladding layer 1102 and to remove the fin hardmasks 304 from the tops of the fins 306. See FIG. 26.
- a nitride material e.g., SiN, SiBCN, SiOCN and/or SiCN
- a nitride-selective etching process such as a nitride-selective RIE can be used for the recess etch.
- the tops of the fins 306 are now exposed.
- Top spacers 2702 are then formed above the cladding layer 1102. See FIG. 27.
- the top spacers 2702 can be formed using a directional deposition process (such as HDP CVD or PVD) whereby a greater amount of a spacer material is deposited onto horizontal surfaces, as compared to vertical surfaces. In that case, a greater thickness of the spacer material will be deposited on top of the (recessed) encapsulation layer 2302, cladding layer 1102 and insulator 2402 than, for example, along the sidewalls of the fins 306.
- a directional deposition process such as HDP CVD or PVD
- top spacers 2702 when an etch is used on the spacer material, the timing of the etch needed to remove the spacer material from the vertical surfaces will leave the top spacers 2702 shown in FIG. 27.
- Suitable materials for the top spacers 2702 include, but are not limited to, oxide spacer materials such as S1O2 and/or SiCO, and nitride spacer materials such as SiN, SiBCN, SiOCN and/or SiCN.
- Top source and drains 2802 are then formed at the (exposed) tops of the fins 306 above the top spacers 2702. See FIG. 28.
- the top source and drains 2802 are formed using epitaxial growth (Si, Ge, SiGe, etc.) from the exposed tops of the fins 306.
- the top source and drains 2802 are doped in-situ (e.g., during growth) or ex-situ (e.g., via ion implantation) with an n-type or p-type dopant.
- suitable n-type dopants include, but are not limited to, phosphorous (P) and arsenic (As), and suitable p-type dopants include boron (B).
- FIGS. 29-31 are images illustrating the critical dimension (CD) change before and after the brush process.
- FIG. 29 is a top-down image 2900 of fins 2902 patterned in a Si substrate.
- Inset 2904 illustrates a stage of the above-described process to which image 2900 corresponds.
- image 2900 is exemplary of the structure described in accordance with the description of FIG. 3 above.
- the fins 2902 as patterned have a CD of about 19.8 nm.
- FIG. 30 is a top-down image 3000 of a monolayer of an (e.g., organic) brush material 3002 having been formed over the fins 2902.
- Inset 3004 illustrates a stage of the above-described process to which image 3000 corresponds.
- image 3000 is exemplary of the structure described in accordance with the description of FIG. 6 above.
- the brush material 3002 increases the CD to about 29.4 nm.
- FIG. 31 is a top-down image 3100 of the brush material 3002 having been patterned.
- Inset 3104 illustrates a stage of the above-described process to which image 3100 corresponds.
- image 3100 is exemplary of the structure described in accordance with the description of FIG. 7 above.
- the CD is from about 23 nm to about 24 nm. Therefore, the thickness of the brush material 3002 is about 2 nm on each side of the fins 2902.
- FIGS. 32 and 33 are images illustrating the two-brush approach to create grafting selectivity.
- FIG. 32 is a three-dimensional image 3200 of the brush material 3002 having been grafted to the fins 2902 and fin hardmasks 3201 (above bottom spacers 3202) and etched.
- Inset 3204 illustrates a stage of the above-described process to which image 3200 corresponds.
- image 3200 is exemplary of the structure described in accordance with the description of FIG. 7 above.
- FIG. 33 is a three-dimensional image 3300 of a monolayer of a second (e.g., Si-containing) brush material 3302 having been grafted to the fin hardmasks 3201 and bottom spacers 3202.
- Inset 3304 illustrates a stage of the above-described process to which image 3300 corresponds.
- image 3300 is exemplary of the structure described in accordance with the description of FIG. 8 above.
- Comparison of box 3206 (FIG. 32) and box 3306 (FIG. 33) indicates that the fin CD does not change considerably while the (e.g., about a 10 nm thick) second brush material 3302 is formed at the base of the fins 2902. If the second brush material 3302 were to graft onto the sidewalls of the fins 2902, then a much apparent fin CD change would be observed. Thus, it is evident that the fins sidewalls are protected, and surface selectivity is created.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Electrodes Of Semiconductors (AREA)
- Thin Film Transistor (AREA)
- Insulated Gate Type Field-Effect Transistor (AREA)
Abstract
Techniques for VFET gate length control are provided. In one aspect, a method of forming a VFET device includes: patterning fins in a substrate; forming first polymer spacers alongside opposite sidewalls of the fins; forming second polymer spacers offset from the fins by the first polymer spacers; removing the first polymer spacers selective to the second polymer spacers; reflowing the second polymer spacers to close a gap to the fins; forming a cladding layer above the second polymer spacers; removing the second polymer spacers; forming gates along opposite sidewalls of the fins exposed in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by removal of the second polymer spacers; forming top spacers above the cladding layer; and forming top source and drains above the top spacers. A VFET device is also provided.
Description
TECHNIQUES FOR VERTICAL FET GATE LENGTH CONTROL
Field of the Invention
[0001] The present invention relates to vertical field-effect transistor (VFET) devices, and more particularly, to techniques for VFET gate length control using a material-based patterning method with self-limiting thickness control.
Background of the Invention
[0002] As opposed to planar complementary metal oxide semiconductor (CMOS) devices, vertical field effect transistors (VFETs) are oriented with a vertical fin channel disposed on a bottom source and drain and a top source and drain disposed on the fin channel. VFETs are being explored as a viable device option for continued CMOS scaling beyond the 7 nanometer (nm) technology node.
[0003] With conventional process flows, the gate length (Lg) of a VFET is primarily controlled by two etch processes. The gate conductor is deposited conformally around the fin followed by (1) an OPL planarization and etch back process (to expose a top of the fin for the top source and drain), and (2) a wet gate metal etch. The gate length is mostly defined at this stage, but subsequent high-k dry etch and OPL ashing may also have very fine effects on the Lg as well. Such an etch-controlled gate length (Lg) is, however, subject to a large variation including within wafer, wafer-to-wafer, batch -to-batch, tool dependency, and pattern density (i.e., etch micro-loading) effect.
[0004] Therefore, VFET fabrication techniques that avoid the above-described etch related variations would be desirable. Therefore, there is a need in the art to address the aforementioned problem.
Summary of the Invention
[0005] Viewed from a first aspect, the present invention provides a method of forming a vertical field-effect transistor (VFET) device, the method comprising the steps of: patterning fins in a substrate; forming bottom source and drains at a base of the fins; forming bottom spacers on the bottom source and drains; forming first polymer spacers alongside opposite sidewalls of the fins, wherein the first polymer spacers comprise a monolayer of a first polymer brush material; forming second polymer spacers on the bottom source and drains offset from the fins by the first polymer spacers, wherein the second polymer spacers comprise a monolayer of a second polymer brush material that is un-grafted to the first polymer brush material; removing the first polymer spacers selective to the second polymer spacers creating a gap between the second polymer spacers and the fins; reflowing the second polymer spacers to close the gap; forming a cladding layer alongside the opposite sidewalls of the fins above the second polymer spacers; removing the second polymer spacers exposing the opposite sidewalls of the fins in
between the bottom spacers and the cladding layer; forming gates along the opposite sidewalls of the fins exposed in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by removal of the second polymer spacers; forming top spacers above the cladding layer; and forming top source and drains above the top spacers.
[0006] Viewed from a further aspect, the present invention provides VFET device, comprising: fins patterned in a substrate; bottom source and drains at a base of the fins; bottom spacers disposed on the bottom source and drains; a cladding layer disposed alongside opposite sidewalls of the fins; gates disposed along the opposite sidewalls of the fins in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by a distance between the bottom spacers and the cladding layer; top spacers disposed above the cladding layer; and top source and drains disposed above the top spacers.
[0007] The present invention provides techniques for vertical field-effect transistor (VFET) gate length control using a material-based patterning method with self-limiting thickness control. In one aspect of the invention, a method of forming a VFET device is provided. The method includes: patterning fins in a substrate; forming bottom source and drains at a base of the fins; forming bottom spacers on the bottom source and drains; forming first polymer spacers alongside opposite sidewalls of the fins, wherein the first polymer spacers include a monolayer of a first polymer brush material; forming second polymer spacers on the bottom source and drains offset from the fins by the first polymer spacers, wherein the second polymer spacers include a monolayer of a second polymer brush material that is un-grafted to the first polymer brush material; removing the first polymer spacers selective to the second polymer spacers creating a gap between the second polymer spacers and the fins; reflowing the second polymer spacers to close the gap; forming a cladding layer alongside the opposite sidewalls of the fins above the second polymer spacers; removing the second polymer spacers exposing the opposite sidewalls of the fins in between the bottom spacers and the cladding layer; forming gates along the opposite sidewalls of the fins exposed in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by removal of the second polymer spacers; forming top spacers above the cladding layer; and forming top source and drains above the top spacers.
[0008] In another aspect of the invention, a VFET device is provided. The VFET device includes: fins patterned in a substrate; bottom source and drains at a base of the fins; bottom spacers disposed on the bottom source and drains; a cladding layer disposed alongside opposite sidewalls of the fins; gates disposed along the opposite sidewalls of the fins in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by a distance between the bottom spacers and the cladding layer; top spacers disposed above the cladding layer; and top source and drains disposed above the top spacers.
[0009] A more complete understanding of the present invention, as well as further features and advantages of the present invention, will be obtained by reference to the following detailed description and drawings.
Brief Description of the Drawings
[0010] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram illustrating a polymer brush according to an embodiment of the present invention; FIG. 2 is a diagram illustrating an exemplary methodology for grafting a monolayer of a polymer brush onto a surface according to an embodiment of the present invention;
FIG. 3 is a cross-sectional diagram illustrating fin hardmasks having been used to pattern at least one fin in a substrate, bottom source and drains having been formed in the substrate at the base of the fins, and bottom spacers having been formed on the bottom source and drains according to an embodiment of the present invention; FIG. 4 is a cross-sectional diagram illustrating a first polymer brush material having been coated onto the fins and bottom spacers according to an embodiment of the present invention;
FIG. 5 is a cross-sectional diagram illustrating a monolayer of the organic polymer brush material having been grafted to the fin hardmasks, the fins, and the bottom spacers according to an embodiment of the present invention; FIG. 6 is a cross-sectional diagram illustrating un-grafted (unreacted) portions of first polymer brush material having been rinsed away leaving behind the monolayer of the organic polymer brush material grafted to the fin hardmasks, the fins, and the bottom spacers according to an embodiment of the present invention;
FIG. 7 is a cross-sectional diagram illustrating the monolayer of the organic polymer brush material having been patterned into first polymer spacers alongside opposite sidewalls of the fins according to an embodiment of the present invention;
FIG. 8 is a cross-sectional diagram illustrating an Si-containing brush material having been grafted to the exposed silicon oxide/nitride surfaces (i.e., of the fin hardmasks and bottom spacers) forming second polymer spacers according to an embodiment of the present invention;
FIG. 9 is a cross-sectional diagram illustrating the first polymer spacers having been removed creating a gap in between the sidewalls of the fins and the second polymer spacers according to an embodiment of the present invention;
FIG. 10 is a cross-sectional diagram illustrating a reflow of the second polymer spacers having been used to close the gap according to an embodiment of the present invention;
FIG. 11 is a cross-sectional diagram illustrating a cladding layer having been deposited over the second polymer spacers and fin hardmasks/fins according to an embodiment of the present invention; FIG. 12 is a cross-sectional diagram illustrating a directional etch having been used to remove the cladding layer from horizontal surfaces including from the top surface of the second polymer spacers in between the fins according to an embodiment of the present invention;
FIG. 13 is a cross-sectional diagram illustrating the fins having been buried in a dielectric fill material according to an embodiment of the present invention;
FIG. 14 is a cross-sectional diagram illustrating the dielectric fill material having been polished down to the fin hardmasks according to an embodiment of the present invention;
FIG. 15 is a cross-sectional diagram illustrating the dielectric fill material as well as the second polymer spacers having been removed selective to the bottom spacers, cladding layer and the fins according to an embodiment of the present invention;
FIG. 16 is a cross-sectional diagram illustrating a gate dielectric having been deposited onto the fin hardmasks, exposed sidewalls of the fins, bottom spacers and cladding layer according to an embodiment of the present invention;
FIG. 17 is a cross-sectional diagram illustrating a gate conductor having been deposited onto the gate dielectric according to an embodiment of the present invention;
FIG. 18 is a cross-sectional diagram illustrating a directional etch having been used to pattern the gate conductor according to an embodiment of the present invention;
FIG. 19 is a cross-sectional diagram illustrating the fin hardmasks/fins, the cladding layer and the gates having been buried in a dielectric fill material according to an embodiment of the present invention;
FIG. 20 is a cross-sectional diagram illustrating an etch having been used to recess the dielectric fill material according to an embodiment of the present invention;
FIG. 21 is a cross-sectional diagram illustrating an etch having been used to recess the gate dielectric according to an embodiment of the present invention;
FIG. 22 is a cross-sectional diagram illustrating the dielectric fill material having been removed according to an embodiment of the present invention;
FIG. 23 is a cross-sectional diagram illustrating an encapsulation layer having been deposited over the fin hardmasks/fins, the cladding layer and the gates according to an embodiment of the present invention;
FIG. 24 is a cross-sectional diagram illustrating an insulator having been deposited over the encapsulation layer, burying the fins according to an embodiment of the present invention;
FIG. 25 is a cross-sectional diagram illustrating an etch having been performed to recess the insulator below the tops of the fins according to an embodiment of the present invention;
FIG. 26 is a cross-sectional diagram illustrating an etch having been performed to recess the encapsulation layer and the cladding layer and to remove the fin hardmasks from the tops of the fins according to an embodiment of the present invention;
FIG. 27 is a cross-sectional diagram illustrating top spacers having been formed above the cladding layer according to an embodiment of the present invention;
FIG. 28 is a cross-sectional diagram illustrating top source and drains having been formed at the tops of the fins above the top spacers according to an embodiment of the present invention;
FIG. 29 is a top-down image of fins patterned in a Si substrate according to an embodiment of the present invention;
FIG. 30 is a top-down image of a monolayer of an (e.g., organic) brush material having been formed over the fins according to an embodiment of the present invention;
FIG. 31 is a top-down image of the organic brush material having been patterned according to an embodiment of the present invention;
FIG. 32 is a three-dimensional image of the organic brush material having been grafted to the fins and fin hardmasks (above bottom spacers) and etched according to an embodiment of the present invention; and
FIG. 33 is a three-dimensional image of a monolayer of a second (e.g., Si-containing) brush material having been grafted to the fin hardmasks and bottom spacers according to an embodiment of the present invention.
Detailed Description of Preferred Embodiments
[0011] As provided above, with vertical field-effect transistor (VFET) devices etch-controlled gate length (Lg) processes are subject to a large variation including within wafer, wafer-to-wafer, batch-to-batch, tool dependency, and pattern density (i.e., etch micro-loading) effect. Advantageously, provided herein are material-based patterning methods that are immune to these etch related variations.
[0012] Specifically, the present techniques leverage a polymer brush system with polymer brushes of self- limiting thicknesses to set the gate length (Lg), rather than etch-based processes. A polymer brush is a linear copolymer of one or more components plus a grafting functional group at one end. See, for example, Mansky et al., “Controlling Polymer-Surface Interactions with Random Copolymer Brushes,” Science, vol. 275, pgs. 1458-1460 (March 1997) (hereinafter“Mansky”). FIG. 1 , for instance, depicts schematically a polymer brush 100. Polymer brush 100 is a linear copolymer having components A and B, as well as a grafting functional group C.
[0013] Advantageously, only one monolayer of the polymer brush can be grafted onto a surface, thereby providing a self-limiting thickness on the surface. See, for example, FIG. 2. As shown in step 202 of FIG. 2, the polymer brush is cast onto a substrate (in this case a silicon (Si) substrate for illustrative purposes only). As shown in step 204, an anneal is used to graft a monolayer of the polymer brush (“Brush grafted”) onto the substrate. According to an exemplary embodiment, the anneal is performed at a temperature of from about 259C to about 3009C, and ranges therebetween, wherein the lower bound is determined by the functional group, and the upper bound is determined by the polymer decomposition.
[0014] The un-grafted portion of the polymer brush is then rinsed away, leaving behind the monolayer of the polymer brush grafted to the substrate. See step 206. Suitable solvents for the rinse include, but are not limited to propylene glycol monomethyl ether acetate (PGMEA), toluene, benzene, xylene, tetrahydrofuran (THF), methyl isobutyl carbinol (MIBC), gamma-butyrolactone (GBA), and combinations thereof. As described in Mansky, the thickness of the polymer brush can be controlled based on the annealing time (duration) but will reach a self-limiting (saturated) thickness determined by the molecular weight of the brush. See, for example, FIG. 1 of Mansky.
[0015] As will be described in detail below, the present techniques employ different types of polymer brushes with different grafting groups having reactivity/selectivity to different surfaces. For instance, by way of example only, a first type of polymer brush material employed will be an organic brush material such as polystyrene (PS):
[0016] Another type of polymer brush material employed will be a Si-containing brush material (“Si brush material”) such as polydimethylsiloxane (PDMS):
[0017] Processing temperature and grafting density will be chosen accordingly.
[0018] An exemplary process for forming a VFET device is now described by way of reference to FIGS. 3-29. As shown in FIG. 3, the process begins with at least one fin 306 being patterned in a substrate 302. According to one exemplary embodiment, the substrate 302 is a bulk semiconductor wafer, such as a bulk silicon (Si), bulk germanium (Ge), bulk silicon germanium (SiGe) and/or bulk lll-V semiconductor wafer. Alternatively, substrate 302 can be a semiconductor-on-insulator (SOI) wafer. A SOI wafer includes a SOI layer separated from an underlying substrate by a buried insulator. When the buried insulator is an oxide it is referred to herein as a buried oxide or BOX. The SOI layer can include any suitable semiconductor, such as Si, Ge, SiGe, and/or a lll-V semiconductor.
[0019] A patterned fin hardmask 304 is formed on the substrate marking the footprint and location of the fins 306. Suitable hardmask materials include, but are not limited to, nitride hardmask materials such as silicon nitride (SiN), silicon boron carbon nitride (SiBCN), silicon oxycarbon nitride (SiOCN), and/or silicon carbon nitride (SiCN). The fin hardmasks 304 are then used to etch the fins 306 in the substrate 302. According to an exemplary embodiment, the fin etch is carried out using a directional etching process such as reactive ion etching (RIE). As shown in FIG. 3, the fins 306, as patterned, extend partway through the substrate 302.
[0020] Next, as shown in FIG. 3, bottom source and drains 308 are formed in the substrate at the base of the fins 306. According to an exemplary embodiment, bottom source and drains 308 are formed using an ion implantation process to introduce dopants into the substrate 302 at the base of the fins 306. Suitable n-type dopants include, but are not limited to, phosphorous (P) and/or arsenic (As). Suitable p-type dopants include, but are not limited to, boron (B). Ion implantation is, however, only one techniques contemplated herein for forming the bottom source and drains 308. For instance, alternatively, an in-situ (i.e., during growth) or ex-situ (e.g., via ion
implantation) doped epitaxial source and drain material (e.g., epitaxial Si, Ge and/or SiGe) can instead be grown at the base of the fins 306.
[0021] Bottom spacers 310 are then formed on the bottom source and drains 308. See FIG. 3. According to an exemplary embodiment, the bottom spacers 310 are formed using a directional deposition process whereby a spacer material is deposited onto the bottom source and drains 308 with a greater amount of the material being deposited on the horizontal surfaces, as compared to the vertical surfaces. In that case, a greater thickness of the spacer material will be deposited on top of the bottom source and drains 308 than, for example, along the sidewalls of the fins 306. Thus, when an etch is used on the spacer material, the timing of the etch needed to remove the spacer material from the vertical surfaces will leave the bottom spacers 310 shown in FIG. 3 on top of the bottom source and drains 308 since a greater amount of the spacer material was present on the bottom source and drains 308 to begin with. By way of example only, a high density plasma (HDP) chemical vapor deposition (CVD) or physical vapor deposition (PVD) process can be used for directional film deposition, and an isotropic etch can be used to remove the (thinner) spacer material deposited onto the vertical surfaces. Suitable materials for the bottom spacers 310 include, but are not limited to, oxide spacer materials such as silicon dioxide (S1O2) and/or silicon carbon oxide (SiCO), and nitride spacer materials such as SiN, SiBCN, SiOCN and/or SiCN.
[0022] As shown in FIG 4, a first polymer brush material 402 is then coated onto the fins 306 and bottom spacers 310. According to an exemplary embodiment, the first polymer brush material 402 is an organic brush material such as polystyrene. An organic polymer brush material does not have a preference for silicon oxide versus nitride, and thus the first polymer brush material 402 will graft to the fin hardmasks 304, the fins 306, and the bottom spacers 310. As shown in FIG 5, thus, following an anneal (suitable conditions were provided above) a conformal, self-limiting thickness layer 502 of the organic polymer brush material is formed grafted to the fin hardmasks 304, the fins 306, and the bottom spacers 310. As shown in FIG 6, the un-grafted (unreacted) portion of first polymer brush material 402 is then rinsed away (see above) leaving behind the conformal layer 502 of the organic polymer brush material grafted to the fin hardmasks 304, the fins 306, and the bottom spacers 310.
[0023] As shown in FIG 7, a directional etching process such as RIE is then used to pattern the layer 502 of the organic polymer brush material into (first) polymer spacers 702 alongside opposite sidewalls of the fins 306. Specifically, this spacer etch serves to remove the layer 502 of the organic polymer brush material from horizontal surfaces, including from the tops of the fin hardmasks 304 and the bottom spacers 310. According to an exemplary embodiment, the polymer spacers 702 have a thickness of from about 2.5 nanometers (nm) to about 3.5 nm, and ranges therebetween.
[0024] Following the spacer etch, there are now exposed surfaces of different materials across the structure. For instance, there are now i) exposed silicon oxide/nitride surfaces (see above) of the fin hardmasks 304 and bottom spacers 310 and ii) exposed polymer surfaces of the polymer spacers 702. Selectivity of a second polymer
brush material for grafting to the silicon oxide/nitride surfaces over the polymer surfaces will then be leveraged to set the gate length (Lg).
[0025] According to an exemplary embodiment, the second polymer brush material is an Si-containing brush material such as PDMS with a -COOH end-functional group (i.e., PDMS provides the SiOx and the end-group provides the grafting selectivity) which grafts selectively to the exposed silicon oxide/nitride surfaces (i.e., of the fin hardmasks 304 and bottom spacers 310) over the polymer surfaces (i.e., of the polymer spacers 702) to form (second) polymer spacers 802. As shown in FIG 8, polymer spacers 802 are formed by the same process described above, whereby the Si-containing brush material is coated onto the fin hardmasks 304 and the bottom spacers 310 using, e.g., a casting process such as spin-coating. It is notable that, while the Si-containing brush material coated on the fin hardmasks 304 can be selectively removed (see below), it is possible to reduce or eliminate the Si-containing brush material on the fin hardmasks 304 by controlling the spin-coating thickness. As shown in FIG. 8, the polymer spacers 802 are offset from the fins 306 by the polymer spacers 702. The end- functional group of the Si-containing brush material has a preference for the exposed silicon oxide/nitride surfaces, and thus will graft to the fin hardmasks 304 and bottom spacers 310 following an anneal (suitable conditions were provided above). The un-grafted (unreacted) portion of the Si-containing brush material is then rinsed away leaving behind the polymer spacers 802 grafted to the fin hardmasks 304 and bottom spacers 310. According to an exemplary embodiment, the polymer spacers 802 are formed having a height h of from about 15 nanometers (nm) to about 20 nm, and ranges therebetween.
[0026] The polymer spacers 802 do not, however, graft to the polymer spacers 702. Thus, as shown in FIG. 9 the polymer spacers 702 can then be easily removed (e.g., via ashing) while oxidizing the polymer spacers 802 into silicon oxide-like materials. Removal of the polymer spacers 702 leaves a precise gap g in between the sidewalls of the fins 306 and the polymer spacers 802 equivalent to the thickness of the monolayer of the first polymer brush material used to form the polymer spacers 702 (see above).
[0027] A reflow of the polymer spacers 802 is then used to close the gap g. As shown in FIG 10, this reflow also results in densification of the polymer spacers 802. According to an exemplary embodiment, the reflow is performed by annealing the polymer spacers 802 at a temperature of from about 5009C to about 10009C, and ranges therebetween.
[0028] As shown in FIG. 10, the reflow and densification will change the volume/height of the polymer spacers 802 (see dashed boxes 1002 indicating the dimensions of polymer spacers 802 prior to reflow). Given the height h of the polymer spacers 802 prior to reflow (see, e.g., FIG. 8 - described above) and the gap g left by removal of the polymer spacers 702 (see, e.g., FIG. 9), the volume change/height difference of the polymer spacers 802 after reflow can be easily estimated. For instance, assuming an infinitely long fin/channel length L (i.e., L »
Dfin ), an (initial) height h of the polymer spacers 802 of 20 nm, and a gap g of 2 nm (on each side of the fins 306), the dimensions of the polymer spacers 802 after reflow can be calculated as follows:
_ Kew {Pitch ) _ (pitch -S - 4)
20 ( pitch - 8)
wherein h is the height of the polymer spacers 802 prior to reflow (see, e.g., FIG. 8 - described above), hnew is the height of the polymer spacers 802 after reflow, Dfin is the width of the fins 306, and tbmsh is the thickness of the first polymer brush material used to form the polymer spacers 702, wherein thmsh is a thickness in the horizontal direction, whereas h and hnew are height measurements in the vertical direction. Pitch is the distance from a given point on one fin 306 to the same given point on an adjacent fin 306.
[0029] A cladding layer 1102 is then conformally deposited over the polymer spacers 802 and fin hardmasks 304/fins 306. As shown in FIG 11 , suitable conformal deposition processes include, but are not limited to, chemical vapor deposition (CVD) and atomic layer deposition (ALD). Suitable cladding materials include, but are not limited to, SiN, SiBCN, SiOCN, and/or SiCN. According to an exemplary embodiment, the cladding layer 1102 is formed having a thickness of from about 5 nm to about 8 nm, and ranges therebetween.
[0030] A directional etch is then used to remove the cladding layer 1102 from horizontal surfaces including from the top surface of the polymer spacers 802 in between the fins 306. As shown in FIG 12, suitable directional etching processes include, but are not limited to, reactive ion etching (RIE). For instance, when the cladding layer 1102 is formed from a nitride material (see above), a nitride-selective RIE can be employed with the (e.g., PDMS) polymer spacers 802 acting as an etch stop. It is notable, however, that this etch selectivity and etch stop on polymer spacers 802 is preferred but not necessary, as the Lg is fixed no matter whether the polymer spacers 802 are recessed or not, as can be seen in FIG. 12. As a result, the cladding layer 1102 remains alongside the opposite sidewalls of the fins 306 and at the tops of the fins 306 above the polymer spacers 802. It is notable that the gate length (Lg), between the bottom spacers 310 and the cladding layer 1102, is set via the height ( /znew - see FIG. 10) of the polymer spacers 802.
[0031] The fins 306 are then buried in a dielectric fill material 1302. As shown in FIG. 13, suitable dielectric fill materials include, but are not limited to, S1O2 and/or SiCO. The dielectric fill material 1302 enables use of a process, such as chemical-mechanical polishing (CMP), to provide a flat, planar surface for further processing.
See, for example, FIG. 14 which illustrates the dielectric fill material 1302 having been polished down to the fin hardmasks 304 using, e.g., CMP.
[0032] The dielectric fill material 1302 as well as the polymer spacers 802 are then removed selective to the bottom spacers 310, cladding layer 1102 and the fins 306. As shown in FIG. 15, according to an exemplary embodiment, the dielectric fill material 1302 and the polymer spacers 802 are both oxide materials (e.g., SiCfe and oxidized PDMS, respectively) which can be removed using a wet etch with hydrofluoric acid (HF) and/or a chemical oxide removal (COR) process. The COR process is described, for example, in Hagimoto et al.,“Evaluation of the plasmaless gaseous etching process,” Solid State Phenomena, vol. 134, pp. 7-10 (2008) (published November 2007), the contents of which are incorporated by reference as if fully set forth herein.
[0033] Gates (i.e., a gate dielectric and gate conductor) are next formed alongside the fins 306. Notably, the amount of the fin 306 sidewalls that is exposed, i.e., based on the distance between the bottom spacers 310 and the cladding layer 1102 (alongside which the gates will be formed) is set by removal of the polymer spacers 802 (e.g., a monolayer of the Si-containing brush material). As shown in FIG.15, this will be used to set the gate length (Lg). By comparison, with conventional processes the gate materials are often deposited over the entire fin and then etched back which sets the gate length. However, such an etch-based process is subject to a large variation including within wafer, wafer-to- wafer, batch-to-batch, tool dependency, and pattern density (i.e., etch microloading) effect.
[0034] To begin the gate formation, a gate dielectric 1602 is first conformally deposited onto the fin hardmasks 304, exposed sidewalls of the fins 306, bottom spacers 310 and cladding layer 1102. As shown in FIG. 16, according to an exemplary embodiment, the gate dielectric 1602 is deposited to a thickness of from about 0.5 nm to about 2 nm, and ranges therebetween. A gate conductor 1702 is then conformally deposited onto the gate dielectric 1602. As shown in FIG. 17, according to an exemplary embodiment, the gate conductor 1702 is deposited to a thickness of from about 4 nm to about 6 nm, and ranges therebetween. Suitable conformal deposition processes include, but are not limited to ALD.
[0035] According to an exemplary embodiment, the gate dielectric 1602 is a high-k gate dielectric and the gate conductor 1702 is a workfunction setting metal. The particular workfunction setting metal employed can vary depending on whether an NFET (n-type workfunction setting metal) or PFET (p-type workfunction setting metal) is being formed. Suitable n-type workfunction setting metals include, but are not limited to, titanium nitride (TiN), tantalum nitride (TaN) and/or aluminum (Al)-containing alloys such as titanium aluminide (TiAI), titanium aluminum nitride (TiAIN), titanium aluminum carbide (TiAIC), tantalum aluminide (TaAI), tantalum aluminum nitride (TaAIN), and/or tantalum aluminum carbide (TaAIC). Suitable p-type workfunction setting metals include, but are not limited to, TiN, TaN, and tungsten (W). TiN and TaN are relatively thick (e.g., greater than about 2 nanometers (nm)) when used as p-type workfunction metals. However, very thin TiN or TaN layers (e.g., less than about 2 nm) may also be
used beneath Al-containing alloys in n-type workfunction stacks to improve electrical properties such as gate leakage currents. Thus, there is some overlap in the exemplary n- and p-type workfunction metals given above.
[0036] The term“high-k” as used herein refers to a material having a relative dielectric constant k which is much higher than that of silicon dioxide (e.g., a dielectric constant k = 25 for hafnium oxide (HfCte) rather than 4 for silicon dioxide). Suitable high-k gate dielectrics include, but are not limited to, HfCte and/or lanthanum oxide (La203).
[0037] As shown in FIG. 17, due to the conformal deposition process, the opening at the tops of the fins 306 might get pinched off before the gate conductor 1702 fully fills the space between the fins 306, resulting in voids in the gate conductor 1702 below the cladding layer 1102. These voids will however be removed via a directional etch performed in the next step.
[0038] Namely, as shown in FIG. 18 a directional etch (e.g., RIE) is used to pattern the gate conductor 1702. This directional etch is shadowed by the cladding layer 1102. Thus, the gate conductor 1702 alongside the fin 306 sidewalls below the cladding layer 1102 remains following the etch. However, the gate conductor 1702 exposed between the fins 306 is removed, and along with it any of the voids that may have formed during the gate conductor 1702 deposition.
[0039] As shown in FIG. 18, this directional etch defines the gate length (Lg) below the cladding layer 1102. As provided above, the amount of exposed fin 306 sidewall is set by removal of the polymer spacers 802, i.e., the monolayer of the Si-containing brush material. Thus, the Lg is defined by the monolayer thickness of the Si- containing brush material which is consistent from one device to another.
[0040] The gate dielectric 1602 is then recessed. However, the recessed height of the gate dielectric 1602 is not critical since the Lg has already been defined. To recess the gate dielectric 1602, the fin hardmasks 304/fins 306, the cladding layer 1102 and the gates are buried in a fill material 1902. As shown in FIG. 19, as shown in FIG. 20, the as-deposited fill material 1902 can be etched back to provide a flat planar surface. Suitable dielectric fill materials include, but are not limited to, organic planarizing (OPL) materials
[0041] An etch is then used to recess the fill material 1902. As shown in FIG. 20, standard lithography and etching techniques can be employed for the recess etch. This recess of the fill material 1902 will set the height of the (to be recessed - see below) gate dielectric 1602. However, as provided above, the recessed height of the gate dielectric 1602 is not critical since the Lg has already been defined. According to an exemplary embodiment, the fill material 2002 is recessed below the tops of the fins 306, but still overlaps the cladding layer 1102. See FIG. 20.
[0042] An etch is then used to recess the gate dielectric 1602. As shown in FIG. 21 , again, standard lithography and etching techniques can be employed for the recess etch. As shown in FIG. 21 , the gate dielectric is recessed to the height of the recessed fill material 1902. The fin hardmasks 304 and the cladding layer 1102 at the tops of the fins 306 are now exposed. The remaining fill material 1902 is then removed, e.g., by ashing. See FIG. 22
[0043] An encapsulation layer 2302 is then conformally deposited over the fin hardmasks 304/fins 306, the cladding layer 1102 and the gates. See FIG. 23. Suitable materials for the encapsulation layer 2302 include, but are not limited to, SiN, SiBCN, SiOCN, and/or SiCN. Suitable conformal deposition processes include, but are not limited to, ALD. According to an exemplary embodiment, the encapsulation layer is formed having a thickness of from about 2 nm to about 3 nm, and ranges therebetween. The encapsulation layer 2302 will protect the gates during the subsequent processing steps.
[0044] Namely, as shown in FIG. 24 an insulator 2402 is then deposited over the encapsulation layer 2302, burying the fins 306. As shown in FIG. 24, the as-deposited insulator 2402 can be polished using a process such as CMP to provide a flat planar surface. Suitable insulators include, but are not limited to, S1O2 and/or SiCO. An etch is then performed to recess the insulator 2402 below the tops of the fins 306. See FIG. 25. By way of example only, when the insulator 2402 is formed from an oxide material (e.g., S1O2 and/or SiCO), an oxide-selective etching process such as an oxide-selective RIE can be used for the recess etch. This recess etch of the insulator 2402 exposes the encapsulation layer 2302, the cladding layer 1102 and the fin hardmasks 304 at the tops of the fins 306.
[0045] An etch is then performed to recess the encapsulation layer 2302 and the cladding layer 1102 and to remove the fin hardmasks 304 from the tops of the fins 306. See FIG. 26. By way of example only, when the encapsulation layer 2302, the cladding layer 1102 and the fin hardmasks 304 are formed from a nitride material (e.g., SiN, SiBCN, SiOCN and/or SiCN), a nitride-selective etching process such as a nitride-selective RIE can be used for the recess etch. Following this recess etch, the tops of the fins 306 are now exposed.
[0046] Top spacers 2702 are then formed above the cladding layer 1102. See FIG. 27. Like the bottom spacers 310, the top spacers 2702 can be formed using a directional deposition process (such as HDP CVD or PVD) whereby a greater amount of a spacer material is deposited onto horizontal surfaces, as compared to vertical surfaces. In that case, a greater thickness of the spacer material will be deposited on top of the (recessed) encapsulation layer 2302, cladding layer 1102 and insulator 2402 than, for example, along the sidewalls of the fins 306. Thus, when an etch is used on the spacer material, the timing of the etch needed to remove the spacer material from the vertical surfaces will leave the top spacers 2702 shown in FIG. 27. Suitable materials for the top spacers 2702 include, but are not limited to, oxide spacer materials such as S1O2 and/or SiCO, and nitride spacer materials such as SiN, SiBCN, SiOCN and/or SiCN.
[0047] Top source and drains 2802 are then formed at the (exposed) tops of the fins 306 above the top spacers 2702. See FIG. 28. According to an exemplary embodiment, the top source and drains 2802 are formed using epitaxial growth (Si, Ge, SiGe, etc.) from the exposed tops of the fins 306. The top source and drains 2802 are doped in-situ (e.g., during growth) or ex-situ (e.g., via ion implantation) with an n-type or p-type dopant. As provided above, suitable n-type dopants include, but are not limited to, phosphorous (P) and arsenic (As), and suitable p-type dopants include boron (B).
[0048] #The present techniques are further illustrated by way of reference to the following, non-limiting examples. FIGS. 29-31 are images illustrating the critical dimension (CD) change before and after the brush process. Specifically, FIG. 29 is a top-down image 2900 of fins 2902 patterned in a Si substrate. Inset 2904 illustrates a stage of the above-described process to which image 2900 corresponds. By way of example only, image 2900 is exemplary of the structure described in accordance with the description of FIG. 3 above. In this example, the fins 2902 as patterned have a CD of about 19.8 nm.
[0049] FIG. 30 is a top-down image 3000 of a monolayer of an (e.g., organic) brush material 3002 having been formed over the fins 2902. Inset 3004 illustrates a stage of the above-described process to which image 3000 corresponds. By way of example only, image 3000 is exemplary of the structure described in accordance with the description of FIG. 6 above. The brush material 3002 increases the CD to about 29.4 nm.
[0050] FIG. 31 is a top-down image 3100 of the brush material 3002 having been patterned. Inset 3104 illustrates a stage of the above-described process to which image 3100 corresponds. By way of example only, image 3100 is exemplary of the structure described in accordance with the description of FIG. 7 above. Following patterning of the brush material 3002 the CD is from about 23 nm to about 24 nm. Therefore, the thickness of the brush material 3002 is about 2 nm on each side of the fins 2902.
[0051] FIGS. 32 and 33 are images illustrating the two-brush approach to create grafting selectivity.
Specifically, FIG. 32 is a three-dimensional image 3200 of the brush material 3002 having been grafted to the fins 2902 and fin hardmasks 3201 (above bottom spacers 3202) and etched. Inset 3204 illustrates a stage of the above-described process to which image 3200 corresponds. By way of example only, image 3200 is exemplary of the structure described in accordance with the description of FIG. 7 above.
[0052] FIG. 33 is a three-dimensional image 3300 of a monolayer of a second (e.g., Si-containing) brush material 3302 having been grafted to the fin hardmasks 3201 and bottom spacers 3202. Inset 3304 illustrates a stage of the above-described process to which image 3300 corresponds. By way of example only, image 3300 is exemplary of the structure described in accordance with the description of FIG. 8 above. Comparison of box 3206 (FIG. 32) and box 3306 (FIG. 33) indicates that the fin CD does not change considerably while the (e.g., about a 10 nm thick) second brush material 3302 is formed at the base of the fins 2902. If the second brush material 3302
were to graft onto the sidewalls of the fins 2902, then a much apparent fin CD change would be observed. Thus, it is evident that the fins sidewalls are protected, and surface selectivity is created.
[0053] Although illustrative embodiments of the present invention have been described herein, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be made by one skilled in the art without departing from the scope of the invention.
Claims
1. A method of forming a vertical field-effect transistor (VFET) device, the method comprising the steps of: patterning fins in a substrate;
forming bottom source and drains at a base of the fins;
forming bottom spacers on the bottom source and drains;
forming first polymer spacers alongside opposite sidewalls of the fins, wherein the first polymer spacers comprise a monolayer of a first polymer brush material;
forming second polymer spacers on the bottom source and drains offset from the fins by the first polymer spacers, wherein the second polymer spacers comprise a monolayer of a second polymer brush material that is ungrafted to the first polymer brush material;
removing the first polymer spacers selective to the second polymer spacers creating a gap between the second polymer spacers and the fins;
reflowing the second polymer spacers to close the gap;
forming a cladding layer alongside the opposite sidewalls of the fins above the second polymer spacers; removing the second polymer spacers exposing the opposite sidewalls of the fins in between the bottom spacers and the cladding layer;
forming gates along the opposite sidewalls of the fins exposed in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by removal of the second polymer spacers;
forming top spacers above the cladding layer; and
forming top source and drains above the top spacers.
2. The method of claim 1 , wherein the first polymer brush material comprises an organic brush material.
3. The method of claim 2, wherein the organic brush material comprises polystyrene.
4. The method of either of claims 2 or 3, wherein the step of forming the first polymer spacers comprises the steps of:
depositing the first polymer brush material onto the fins and the bottom spacers;
annealing the first polymer brush material to graft the monolayer of the first polymer brush material to the fins and the bottom spacers; and
removing un-grafted portions of the first polymer brush material leaving behind the monolayer of the first polymer brush material grafted to the fins and the bottom spacers.
5. The method of claim 4, wherein the first polymer brush material is annealed at a temperature of from about 259C to about3009C and ranges therebetween.
6. The method of either of claims 4 or 5, wherein the un-grafted portions of the first polymer brush material are removed by rinsing the first polymer brush material with a solvent selected from the group consisting of:
propylene glycol monomethyl ether acetate, toluene, benzene, xylene, tetrahydrofuran, methyl isobutyl carbinol, gamma-butyrolactone, and combinations thereof.
7. The method of any of claims 4 to 6, further comprising the step of:
patterning the monolayer of the first polymer brush material into the first polymer spacers.
8. The method of any of the preceding claims, wherein the second polymer brush material comprises a silicon (Si)-containing brush material.
9. The method of claim 8, wherein the Si-containing brush material comprises polydimethylsiloxane.
10. The method of either of claims 8 or 9, wherein the step of forming the second polymer spacers comprises the steps of:
depositing the second polymer brush material onto the bottom spacers;
annealing the second polymer brush material to graft the monolayer of the second polymer brush material to the bottom spacers; and
removing un-grafted portions of the second polymer brush material leaving behind the monolayer of the second polymer brush material grafted to the bottom spacers.
11. The method of claim 10, wherein the second polymer brush material is annealed at a temperature of from about 259C to about 3009C, and ranges therebetween.
12. The method of either of claims 10 or 11 , wherein the un-grafted portions of the second polymer brush material are removed by rinsing the second polymer brush material with a solvent selected from the group consisting of: propylene glycol monomethyl ether acetate, toluene, benzene, xylene, tetrahydrofuran, methyl isobutyl carbinol, gamma-butyrolactone, and combinations thereof.
13. The method of any of the preceding claims, wherein the first polymer spacers are removed by ashing.
14. The method of any of the preceding claims, wherein the step of reflowing the second polymer spacers comprises the step of:
annealing the second polymer spacers at a temperature of from about 5009C to about 10009C, and ranges therebetween.
15. The method of any of the preceding claims, wherein the step of forming the gates comprises the steps of:
depositing a gate dielectric onto the opposite sidewalls of the fins exposed in between the bottom spacers and the cladding layer; and
depositing a gate conductor onto the gate dielectric.
16. The method of claim 15, wherein the gate dielectric comprises a high-k gate dielectric selected from the group consisting of: hafnium oxide (Hf02), lanthanum oxide (La203), and combinations thereof.
17. The method of either of claims 15 or 16, wherein the gate conductor comprises a workf unction setting metal selected from the group consisting of: titanium nitride (TiN), tantalum nitride (TaN), aluminum (Al)-containing alloys, titanium aluminide (TiAI), titanium aluminum nitride (TiAIN), titanium aluminum carbide (TiAIC), tantalum aluminide (TaAI), tantalum aluminum nitride (TaAIN), tantalum aluminum carbide (TaAIC), tungsten (W), and combinations thereof.
18. The method of v, further comprising the step of:
depositing an encapsulation layer over the cladding layer and the gates, wherein the encapsulation layer comprises a material selected from the group consisting of: silicon nitride (SiN), silicon boron carbon nitride (SiBCN), silicon oxycarbon nitride (SiOCN), silicon carbon nitride (SiCN), and combinations thereof.
19. A VFET device, comprising:
fins patterned in a substrate;
bottom source and drains at a base of the fins;
bottom spacers disposed on the bottom source and drains;
a cladding layer disposed alongside opposite sidewalls of the fins;
gates disposed along the opposite sidewalls of the fins in between the bottom spacers and the cladding layer, wherein the gates have a gate length Lg set by a distance between the bottom spacers and the cladding layer;
top spacers disposed above the cladding layer; and
top source and drains disposed above the top spacers.
20. The VFET device of claim 19, further comprising:
an encapsulation layer disposed over the cladding layer and the gates, wherein the encapsulation layer comprises a material selected from the group consisting of: SiN, SiBCN, SiOCN, SiCN, and combinations thereof.
21. The VFET device of either of claims 19 or 20, wherein the gates comprise:
a gate dielectric disposed on the opposite sidewalls of the fins in between the bottom spacers and the cladding layer; and
a gate conductor disposed on the gate dielectric.
22. The VFET device of claim 21 , wherein the gate dielectric comprises a high-k gate dielectric selected from the group consisting of: HfCte, La203, and combinations thereof.
23. The VFET device of either of claims 21 or 22, wherein the gate conductor comprises a workfunction setting metal selected from the group consisting of:
TiN, TaN, Al-containing alloys, TiAI, TiAIN, TiAIC, TaAI, TaAIN, TaAIC, W, and combinations thereof.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020540573A JP2021513213A (en) | 2018-02-01 | 2019-01-18 | How to Form a Vertical Field Effect Transistor (VFET) Device and VFET Device |
CN201980008379.1A CN111954920A (en) | 2018-02-01 | 2019-01-18 | Vertical FET gate length control techniques |
EP19747021.4A EP3747038A4 (en) | 2018-02-01 | 2019-01-18 | Techniques for vertical fet gate length control |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/886,539 US10475905B2 (en) | 2018-02-01 | 2018-02-01 | Techniques for vertical FET gate length control |
US15/886,539 | 2018-02-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019150215A1 true WO2019150215A1 (en) | 2019-08-08 |
Family
ID=67392395
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2019/050422 WO2019150215A1 (en) | 2018-02-01 | 2019-01-18 | Techniques for vertical fet gate length control |
Country Status (5)
Country | Link |
---|---|
US (2) | US10475905B2 (en) |
EP (1) | EP3747038A4 (en) |
JP (1) | JP2021513213A (en) |
CN (1) | CN111954920A (en) |
WO (1) | WO2019150215A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10475905B2 (en) * | 2018-02-01 | 2019-11-12 | International Business Machines Corporation | Techniques for vertical FET gate length control |
US11282752B2 (en) | 2020-02-05 | 2022-03-22 | Samsung Electronics Co., Ltd. | Method of forming vertical field-effect transistor devices having gate liner |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080128801A1 (en) * | 2006-11-27 | 2008-06-05 | Rohm Co., Ltd. | Semiconductor device |
CN103843120A (en) * | 2011-10-12 | 2014-06-04 | 国际商业机器公司 | Vertical transistor having an asymmetric gate |
CN104919596A (en) * | 2012-11-30 | 2015-09-16 | 佛罗里达大学研究基金会有限公司 | Ambipolar vertical field effect transistor |
US20160122580A1 (en) * | 2014-10-30 | 2016-05-05 | Az Electronic Materials (Luxembourg) S.A.R.L. | Defect reduction methods and composition for via formation in directed self-assembly patterning |
US9530863B1 (en) | 2016-04-13 | 2016-12-27 | Globalfoundries Inc. | Methods of forming vertical transistor devices with self-aligned replacement gate structures |
US9653457B2 (en) | 2015-01-16 | 2017-05-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Stacked device and associated layout structure |
CN106876450A (en) * | 2017-03-06 | 2017-06-20 | 上海矽望电子科技有限公司 | The vertical fet and its manufacture method of low gate leakage capacitance |
US9711618B1 (en) | 2016-03-31 | 2017-07-18 | International Business Machines Corporation | Fabrication of vertical field effect transistor structure with controlled gate length |
CN107393960A (en) * | 2016-04-29 | 2017-11-24 | 三星电子株式会社 | Vertical field-effect transistor and its manufacture method |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6413587B1 (en) * | 1999-03-02 | 2002-07-02 | International Business Machines Corporation | Method for forming polymer brush pattern on a substrate surface |
US6423465B1 (en) | 2000-01-28 | 2002-07-23 | International Business Machines Corporation | Process for preparing a patterned continuous polymeric brush on a substrate surface |
DE10033112C2 (en) * | 2000-07-07 | 2002-11-14 | Siemens Ag | Process for the production and structuring of organic field-effect transistors (OFET), OFET produced thereafter and its use |
CN100418011C (en) | 2001-01-08 | 2008-09-10 | 国际商业机器公司 | Method for the manufacture of micro structures |
GB0309355D0 (en) * | 2003-04-24 | 2003-06-04 | Univ Cambridge Tech | Organic electronic devices incorporating semiconducting polymer |
US7384852B2 (en) * | 2006-10-25 | 2008-06-10 | International Business Machines Corporation | Sub-lithographic gate length transistor using self-assembling polymers |
JP5234533B2 (en) * | 2007-03-26 | 2013-07-10 | 国立大学法人九州大学 | Organic semiconductor device and manufacturing method thereof |
US8815747B2 (en) | 2010-06-03 | 2014-08-26 | Micron Technology, Inc. | Methods of forming patterns on substrates |
WO2012134052A2 (en) * | 2011-03-29 | 2012-10-04 | 인하대학교 산학협력단 | Hybrid layer including an oxide layer or an organic layer and an organic polymer layer, and method for preparing same |
US8697523B2 (en) * | 2012-02-06 | 2014-04-15 | International Business Machines Corporation | Integration of SMT in replacement gate FINFET process flow |
US8822619B1 (en) * | 2013-02-08 | 2014-09-02 | Rohm And Haas Electronic Materials Llc | Directed self assembly copolymer composition and related methods |
US20150024597A1 (en) | 2013-07-16 | 2015-01-22 | HGST Netherlands B.V. | Method for sidewall spacer line doubling using polymer brush material as a sacrificial layer |
US9184058B2 (en) | 2013-12-23 | 2015-11-10 | Micron Technology, Inc. | Methods of forming patterns by using a brush layer and masks |
KR20160066667A (en) * | 2014-12-02 | 2016-06-13 | 삼성전자주식회사 | Method for forming patterns of semiconductor device |
US9576817B1 (en) | 2015-12-03 | 2017-02-21 | International Business Machines Corporation | Pattern decomposition for directed self assembly patterns templated by sidewall image transfer |
US11056391B2 (en) * | 2016-06-30 | 2021-07-06 | International Business Machines Corporation | Subtractive vFET process flow with replacement metal gate and metallic source/drain |
US9685537B1 (en) | 2016-09-29 | 2017-06-20 | Globalfoundries Inc. | Gate length control for vertical transistors and integration with replacement gate flow |
US9972494B1 (en) * | 2016-11-15 | 2018-05-15 | Globalfoundries Inc. | Method and structure to control channel length in vertical FET device |
US9780197B1 (en) | 2016-12-14 | 2017-10-03 | Globalfoundries Inc. | Method of controlling VFET channel length |
US9935018B1 (en) * | 2017-02-17 | 2018-04-03 | Globalfoundries Inc. | Methods of forming vertical transistor devices with different effective gate lengths |
US10475905B2 (en) * | 2018-02-01 | 2019-11-12 | International Business Machines Corporation | Techniques for vertical FET gate length control |
-
2018
- 2018-02-01 US US15/886,539 patent/US10475905B2/en not_active Expired - Fee Related
-
2019
- 2019-01-18 JP JP2020540573A patent/JP2021513213A/en active Pending
- 2019-01-18 CN CN201980008379.1A patent/CN111954920A/en active Pending
- 2019-01-18 WO PCT/IB2019/050422 patent/WO2019150215A1/en unknown
- 2019-01-18 EP EP19747021.4A patent/EP3747038A4/en not_active Withdrawn
- 2019-10-09 US US16/597,713 patent/US10978576B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080128801A1 (en) * | 2006-11-27 | 2008-06-05 | Rohm Co., Ltd. | Semiconductor device |
CN103843120A (en) * | 2011-10-12 | 2014-06-04 | 国际商业机器公司 | Vertical transistor having an asymmetric gate |
CN104919596A (en) * | 2012-11-30 | 2015-09-16 | 佛罗里达大学研究基金会有限公司 | Ambipolar vertical field effect transistor |
US20160122580A1 (en) * | 2014-10-30 | 2016-05-05 | Az Electronic Materials (Luxembourg) S.A.R.L. | Defect reduction methods and composition for via formation in directed self-assembly patterning |
US9653457B2 (en) | 2015-01-16 | 2017-05-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Stacked device and associated layout structure |
US9711618B1 (en) | 2016-03-31 | 2017-07-18 | International Business Machines Corporation | Fabrication of vertical field effect transistor structure with controlled gate length |
US9530863B1 (en) | 2016-04-13 | 2016-12-27 | Globalfoundries Inc. | Methods of forming vertical transistor devices with self-aligned replacement gate structures |
CN107393960A (en) * | 2016-04-29 | 2017-11-24 | 三星电子株式会社 | Vertical field-effect transistor and its manufacture method |
CN106876450A (en) * | 2017-03-06 | 2017-06-20 | 上海矽望电子科技有限公司 | The vertical fet and its manufacture method of low gate leakage capacitance |
Non-Patent Citations (1)
Title |
---|
See also references of EP3747038A4 * |
Also Published As
Publication number | Publication date |
---|---|
JP2021513213A (en) | 2021-05-20 |
US20190237562A1 (en) | 2019-08-01 |
CN111954920A (en) | 2020-11-17 |
US20200044055A1 (en) | 2020-02-06 |
EP3747038A1 (en) | 2020-12-09 |
US10978576B2 (en) | 2021-04-13 |
EP3747038A4 (en) | 2021-03-03 |
US10475905B2 (en) | 2019-11-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10170596B2 (en) | Fabrication of an isolated dummy fin between active vertical fins with tight fin pitch | |
US9837405B1 (en) | Fabrication of a vertical fin field effect transistor having a consistent channel width | |
CN110235224B (en) | Bottom dielectric isolation method for vertical transmission fin field effect transistor | |
US9905663B2 (en) | Fabrication of a vertical fin field effect transistor with a reduced contact resistance | |
US20200006156A1 (en) | Nonplanar Device and Strain-Generating Channel Dielectric | |
US10833073B2 (en) | Vertical transistors with different gate lengths | |
US10340364B2 (en) | H-shaped VFET with increased current drivability | |
US9343325B2 (en) | Trilayer SIT process with transfer layer for FINFET patterning | |
US10985064B2 (en) | Buried power and ground in stacked vertical transport field effect transistors | |
US10622352B2 (en) | Fin cut to prevent replacement gate collapse on STI | |
US10229983B1 (en) | Methods and structures for forming field-effect transistors (FETs) with low-k spacers | |
US20140312395A1 (en) | Self-aligned borderless contacts using a photo-patternable dielectric material as a replacement contact | |
US10763342B2 (en) | Semiconductor devices having equal thickness gate spacers | |
US10978576B2 (en) | Techniques for vertical FET gate length control | |
US11437489B2 (en) | Techniques for forming replacement metal gate for VFET | |
US10763118B2 (en) | Cyclic selective deposition for tight pitch patterning | |
US10796966B2 (en) | Vertical FET with various gate lengths by an oxidation process | |
US11183583B2 (en) | Vertical transport FET with bottom source and drain extensions | |
US11562908B2 (en) | Dielectric structure to prevent hard mask erosion |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 19747021 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2020540573 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2019747021 Country of ref document: EP Effective date: 20200901 |