CN104576340A - Method for forming top fillets of deep trenches - Google Patents
Method for forming top fillets of deep trenches Download PDFInfo
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- CN104576340A CN104576340A CN201310484873.XA CN201310484873A CN104576340A CN 104576340 A CN104576340 A CN 104576340A CN 201310484873 A CN201310484873 A CN 201310484873A CN 104576340 A CN104576340 A CN 104576340A
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- Prior art keywords
- deep trench
- etching
- deep
- deep trenches
- wet
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- 238000000034 method Methods 0.000 title claims abstract description 26
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims abstract description 24
- 238000005530 etching Methods 0.000 claims abstract description 23
- 238000001039 wet etching Methods 0.000 claims abstract description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- 239000000377 silicon dioxide Substances 0.000 claims description 14
- 235000012239 silicon dioxide Nutrition 0.000 claims description 13
- 239000007789 gas Substances 0.000 claims description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 8
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 4
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 2
- XEMZLVDIUVCKGL-UHFFFAOYSA-N hydrogen peroxide;sulfuric acid Chemical compound OO.OS(O)(=O)=O XEMZLVDIUVCKGL-UHFFFAOYSA-N 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 2
- 230000005684 electric field Effects 0.000 abstract description 3
- 230000001154 acute effect Effects 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 238000004140 cleaning Methods 0.000 abstract 1
- 101100269850 Caenorhabditis elegans mask-1 gene Proteins 0.000 description 10
- 238000001312 dry etching Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- -1 make exposed portion Inorganic materials 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon 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
- H01L29/40—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
- H01L29/42356—Disposition, e.g. buried gate electrode
- H01L29/4236—Disposition, e.g. buried gate electrode within a trench, e.g. trench gate electrode, groove gate electrode
-
- 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
- H01L21/3065—Plasma etching; Reactive-ion etching
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Ceramic Engineering (AREA)
- Plasma & Fusion (AREA)
- Manufacturing & Machinery (AREA)
- Weting (AREA)
Abstract
The invention discloses a method for forming top fillets of deep trenches. After deep trench etching, the method comprises the following steps: (1), deep trench hard masks are subjected to wet etch-back to enable part of single crystal silicon surface to be exposed out of the top of the deep trenches; (2), single crystal silicon is subjected to anisotropic etching to enable the single crystal silicon exposed out of the top of the deep trenches to form step-shaped contours; (3), the step (1) and the step (2) are repeated according to the size of top fillets required to be formed; (4), residual deep trench hard masks are removed through wet etching; (5), mild isotropic etching is performed to revise the step-shaped contours at the top of the deep trenches into a fillet shape; (6), wet cleaning is performed to finish the production of the top fillets of the deep trenches. Step-shaped morphology is formed at the top of the deep trenches firstly, then each fillet is produced at a top opening of each deep trench through isotropic etching of the single crystal silicon, therefore, acute angled morphology in a device is reduced, and the electric field intensity of the top areas of the deep trenches and the risks of electric leakage and failure of a trench type IGBT (insulated gate bipolar transistor) are reduced.
Description
Technical field
The present invention relates to IC manufacturing field, particularly relate to the formation process method of deep trench top fillet.
Background technology
Groove-shaped IGBT(insulated gate bipolar transistor) grid be by deep plough groove etched, then polysilicon deposition is formed, this design improves gully density effectively, but this technique deep plough groove etched complete after, the right angle of 90 degree can be formed on deep trench top, therefore comparatively strong in this region electric field strength, cause device to lose efficacy because of electric leakage between grid and emitter.
Summary of the invention
The technical problem to be solved in the present invention is to provide the formation method of a kind of deep trench top fillet, and it can reduce the risk of element leakage.
For solving the problems of the technologies described above, the formation method of deep trench top of the present invention fillet, complete deep plough groove etched after, include following steps:
1) wet method is returned and is carved the hard mask of deep trench, makes exposed portion, deep trench top monocrystalline silicon surface;
2) monocrystalline silicon anisotropic etching, the monocrystalline silicon that deep trench top is exposed forms stair-stepping profile;
3) size of the top fillet formed as required, repeats step 1) ~ 2);
4) wet etching, removes the hard mask of remaining deep trench completely;
5) slight isotropic etching, is radiussed by the contour revising of deep trench top step shape;
6) wet-cleaned, completes the making of deep trench top fillet.
The present invention is by first forming stair-stepping pattern at deep trench top, recycling monocrystalline silicon isotropic etching, deep trench open top is made into a fillet, as this reduced the pattern of acute angle in device, reduce the electric field strength of deep trench top area, thus reduce the risk that electric leakage inefficacy occurs groove-shaped IGBT device.
Accompanying drawing explanation
Fig. 1 ~ Fig. 7 is the process flow diagram of the embodiment of the present invention.
Fig. 8 is the front elevation of the deep trench of the top fillet profile that the embodiment of the present invention makes.
Fig. 9 is the inclination figure of the deep trench of the top fillet profile that the embodiment of the present invention makes.
Figure 10 ~ Figure 14 is the process schematic diagram forming more Rouno Cormer Pregrinding Wheel at deep trench top.
In figure, description of reference numerals is as follows:
1: the hard mask of silicon dioxide
2: monocrystalline substrate
3: monocrystalline silicon deep trench
4: one-level step-shaped top contouring
5: top fillet
6: two stage steps top profile
7: three grades of step-shaped top contourings
8: top Rouno Cormer Pregrinding Wheel
Embodiment
Understand more specifically for having technology contents of the present invention, feature and effect, now by reference to the accompanying drawings, details are as follows:
The formation method of the deep trench top fillet of the present embodiment, specifically comprises following processing step:
Step 1, the hard mask 1 of deposit silicon dioxide in monocrystalline substrate 2, as shown in Figure 1.
The thickness of the hard mask of silicon dioxide 1 is that the radius that deep plough groove etched required hard mask thicknesses adds upper top fillet 5 adds slight isotropic etching amount.Such as, 5 ~ 6 micron trenches degree of depth,
top radius of corner, just needs
above silicon dioxide thickness.
Step 2, silicon dioxide hard mask 1 dry etching and removing photoresist, forms the figure of monocrystalline silicon deep trench 3, as shown in Figure 2.
This step is mainly through photoetching and adopt with gas CF
4be main etching condition, form the figure of monocrystalline silicon deep trench 3, then remove photoresist by wet method.
Step 3, dry etching, forms vertical monocrystalline silicon deep trench 3, as shown in Figure 3.
The etching gas of this step dry etching mainly comprises SF
6, Cl
2, HBr, CF
4, O
2, CHF
3deng gas.
Step 4, wet method is returned and is carved the hard mask 1 of silicon dioxide, as shown in Figure 4.
This step uses buffered hydrofluoric acid liquid to soak, and returns and carves the hard mask 1 of part of silica, make exposed portion, monocrystalline silicon deep trench 3 top monocrystalline silicon surface.
the top fillet 5 of radius needs back to carve
the hard mask 1 of silicon dioxide.
Step 5, monocrystalline silicon anisotropic etching, carves a step the top single crystalline silicon come out because of the returning quarter of step 4, forms the stepped top monocrystalline silicon profile on separate unit rank, as shown in Figure 5.
The etching gas of this step etching is with CF
4gas is main.Etch amount will calculate accurately, can not be destroyed with bonding crystal silicon deep trench 3 bottom profile.
the top fillet 5 just etching of radius
monocrystalline silicon.
Step 6, wet etching removes the hard mask 1 of silicon dioxide, forms top one-level step, as shown in Figure 6.
The main buffered hydrofluoric acid liquid that adopts of this step soaks, and hard for remaining silicon dioxide mask 1 is all removed.
Step 7, slight isotropic etching, forms top fillet 5, as shown in Figure 7.
This step, mainly by slight isotropic etching, is modified to radiussed stair-stepping monocrystalline silicon top profile.Etching gas is with CF
4, O
2gas is main.Etch amount can not greatly (general consistent with the radius of top fillet 5), otherwise can make stepped monocrystalline silicon plane domain form depression.
Step 8, wet-cleaned, by the immersion of concentrated sulfuric acid hydrogen peroxide and ammoniacal liquor hydrogen peroxide, cleans up organic and inorganic impurity.
The pattern of the deep trench of the top fillet profile finally formed as shown in Figure 8,9.
Above-mentioned steps 4 and step 5 can circulate according to actual needs and carry out, and to obtain the stepped top monocrystalline silicon profile on multiple stage rank, and (top radius of corner is less than finally to form larger top fillet
, be suitable for separate unit rank).Such as shown in Figure 10 ~ 14, after one-level step-shaped top contouring 4 is formed, if repeat step 4 wet method to return silicon dioxide at quarter hard mask 1(Figure 10) and step 5 monocrystalline silicon anisotropic etching (Figure 11), after silicon dioxide hard mask 1 wet etching, just can form two stage steps top profile 6(Figure 12); If repeat twice step 4 and step 5, after silicon dioxide hard mask 1 wet etching, just can form three grades of step-shaped top contouring 7(Figure 13).After slight isotropic etching, just can form larger top Rouno Cormer Pregrinding Wheel 8(Figure 14 at deep trench top).
Claims (8)
1. the formation method of deep trench top fillet, is characterized in that, complete deep plough groove etched after, include following steps:
1) wet method is returned and is carved the hard mask of deep trench, makes exposed portion, deep trench top monocrystalline silicon surface;
2) monocrystalline silicon anisotropic etching, the monocrystalline silicon that deep trench top is exposed forms stair-stepping profile;
3) size of the top fillet formed as required, repeats step 1) ~ 2);
4) wet etching, removes the hard mask of remaining deep trench completely;
5) slight isotropic etching, is radiussed by the contour revising of deep trench top step shape;
6) wet-cleaned, completes the making of deep trench top fillet.
2. method according to claim 1, is characterized in that, step 1), and the hard mask of described deep trench is silicon dioxide.
3. method according to claim 2, is characterized in that, step 1), uses buffered hydrofluoric acid liquid to carry out wet method and returns quarter.
4. method according to claim 1, is characterized in that, step 2), etching gas mainly comprises CF4 gas.
5. method according to claim 1, is characterized in that, step 4), uses buffered hydrofluoric acid liquid to carry out wet etching.
6. method according to claim 1, is characterized in that, step 5), and etching gas mainly comprises CF4, O2 gas.
7. method according to claim 1, is characterized in that, step 5), and etch amount is identical with the radius of top fillet.
8. method according to claim 1, is characterized in that, step 6), uses concentrated sulfuric acid hydrogen peroxide and ammoniacal liquor hydrogen peroxide to carry out wet-cleaned.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310484873.XA CN104576340A (en) | 2013-10-16 | 2013-10-16 | Method for forming top fillets of deep trenches |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310484873.XA CN104576340A (en) | 2013-10-16 | 2013-10-16 | Method for forming top fillets of deep trenches |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104576340A true CN104576340A (en) | 2015-04-29 |
Family
ID=53092122
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310484873.XA Pending CN104576340A (en) | 2013-10-16 | 2013-10-16 | Method for forming top fillets of deep trenches |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104576340A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108074800A (en) * | 2016-11-16 | 2018-05-25 | 株洲中车时代电气股份有限公司 | Manufacturing silicon carbide semiconductor base material trench gate engraving method |
| CN110071039A (en) * | 2019-04-29 | 2019-07-30 | 苏州工业园区纳米产业技术研究院有限公司 | Deep silicon trench lithographic method and silicon device |
| CN111081542A (en) * | 2018-10-19 | 2020-04-28 | 北京北方华创微电子装备有限公司 | Method for etching top fillet of main body appearance |
| CN111106003A (en) * | 2019-11-20 | 2020-05-05 | 上海华虹宏力半导体制造有限公司 | Method for rounding top of trench |
| CN111244167A (en) * | 2020-01-19 | 2020-06-05 | 上海华虹宏力半导体制造有限公司 | Gate groove filling method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040033695A1 (en) * | 2002-08-13 | 2004-02-19 | Go Saito | Method for manufacturing semiconductor device |
| KR100588642B1 (en) * | 2004-12-22 | 2006-06-12 | 동부일렉트로닉스 주식회사 | Method for improving the trench corner rounding |
| CN1808705A (en) * | 2005-01-18 | 2006-07-26 | 旺宏电子股份有限公司 | Shallow trench isolation method forming round corners by cleaning |
-
2013
- 2013-10-16 CN CN201310484873.XA patent/CN104576340A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040033695A1 (en) * | 2002-08-13 | 2004-02-19 | Go Saito | Method for manufacturing semiconductor device |
| KR100588642B1 (en) * | 2004-12-22 | 2006-06-12 | 동부일렉트로닉스 주식회사 | Method for improving the trench corner rounding |
| CN1808705A (en) * | 2005-01-18 | 2006-07-26 | 旺宏电子股份有限公司 | Shallow trench isolation method forming round corners by cleaning |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108074800A (en) * | 2016-11-16 | 2018-05-25 | 株洲中车时代电气股份有限公司 | Manufacturing silicon carbide semiconductor base material trench gate engraving method |
| CN108074800B (en) * | 2016-11-16 | 2020-01-14 | 株洲中车时代电气股份有限公司 | Silicon carbide semiconductor substrate trench gate etching method |
| CN111081542A (en) * | 2018-10-19 | 2020-04-28 | 北京北方华创微电子装备有限公司 | Method for etching top fillet of main body appearance |
| CN110071039A (en) * | 2019-04-29 | 2019-07-30 | 苏州工业园区纳米产业技术研究院有限公司 | Deep silicon trench lithographic method and silicon device |
| CN111106003A (en) * | 2019-11-20 | 2020-05-05 | 上海华虹宏力半导体制造有限公司 | Method for rounding top of trench |
| CN111244167A (en) * | 2020-01-19 | 2020-06-05 | 上海华虹宏力半导体制造有限公司 | Gate groove filling method |
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Application publication date: 20150429 |
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