JP6784237B2 - Manufacturing method of silicon epitaxial wafer - Google Patents
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- JP6784237B2 JP6784237B2 JP2017138250A JP2017138250A JP6784237B2 JP 6784237 B2 JP6784237 B2 JP 6784237B2 JP 2017138250 A JP2017138250 A JP 2017138250A JP 2017138250 A JP2017138250 A JP 2017138250A JP 6784237 B2 JP6784237 B2 JP 6784237B2
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims description 66
- 229910052710 silicon Inorganic materials 0.000 title claims description 66
- 239000010703 silicon Substances 0.000 title claims description 66
- 238000004519 manufacturing process Methods 0.000 title claims description 21
- 238000004140 cleaning Methods 0.000 claims description 130
- 239000000758 substrate Substances 0.000 claims description 47
- 229910052799 carbon Inorganic materials 0.000 claims description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 28
- 150000002500 ions Chemical class 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 23
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 16
- -1 carbon ions Chemical class 0.000 claims description 12
- 238000005468 ion implantation Methods 0.000 claims description 7
- 235000012431 wafers Nutrition 0.000 description 41
- 238000011109 contamination Methods 0.000 description 31
- 239000002245 particle Substances 0.000 description 27
- 239000010410 layer Substances 0.000 description 20
- 230000007547 defect Effects 0.000 description 14
- 238000005406 washing Methods 0.000 description 8
- 238000005247 gettering Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 238000004445 quantitative analysis Methods 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 238000001444 catalytic combustion detection Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005202 decontamination Methods 0.000 description 1
- 230000003588 decontaminative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- MMBMIVSDYYPRHH-UHFFFAOYSA-N hydrogen peroxide Chemical compound OO.OO MMBMIVSDYYPRHH-UHFFFAOYSA-N 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 230000005660 hydrophilic surface Effects 0.000 description 1
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
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- Chemical Vapour Deposition (AREA)
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- Cleaning Or Drying Semiconductors (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Physical Vapour Deposition (AREA)
Description
本発明は、シリコンエピタキシャルウェーハの製造方法及びシリコンエピタキシャルウェーハに関し、特に、半導体シリコン基板に炭素を含むイオンを注入した後、半導体シリコン基板表面にエピタキシャル層を形成するシリコンエピタキシャルウェーハの製造方法に関する。 The present invention relates to a method for manufacturing a silicon epitaxial wafer and a silicon epitaxial wafer, and more particularly to a method for manufacturing a silicon epitaxial wafer in which an epitaxial layer is formed on the surface of a semiconductor silicon substrate after injecting ions containing carbon into the semiconductor silicon substrate.
ＣＣＤ、ＣＩＳ等の固体撮像素子等の半導体装置の微細化、高性能化に伴い、それらの製品歩留まりを向上させるために、材料としての基板にも高品質化が要求され、これに対応した各種シリコンウェーハが開発されている。 With the miniaturization and higher performance of semiconductor devices such as solid-state image sensors such as CCD and CIS, in order to improve the yield of those products, the substrate as a material is also required to have high quality, and various types corresponding to this. Silicon wafers are being developed.
特に、製品特性に直接影響を与えるウェーハ表層部の汚染及び結晶欠陥の低減は大変重要であり、その改善策として、エピタキシャルウェーハのゲッタリング能力を高める手法の開発が進められている。その中でも、シリコン基板に炭素を含むイオンを注入し、シリコン基板表面にエピタキシャル層を形成したエピタキシャルウェーハは、先端デバイス特性改善に有力な方法として開発が進められている。 In particular, reduction of contamination and crystal defects on the surface layer of the wafer, which directly affects the product characteristics, is very important, and as a measure for improvement, a method for increasing the gettering ability of the epitaxial wafer is being developed. Among them, an epitaxial wafer in which ions containing carbon are injected into a silicon substrate to form an epitaxial layer on the surface of the silicon substrate is being developed as a promising method for improving the characteristics of advanced devices.
従来のエピタキシャル層形成前の基板の洗浄方法としては、ＳＣ−１＋ＳＣ−２洗浄だけで行っており、その洗浄の目的は、汚染及びパーティクルの除去のために行っていた（特許文献１）。しかしながら、炭素を含むイオンを注入した基板にこのような洗浄方法を適用しても、汚染やパーティクルの除去は十分ではないという問題があった。 As a conventional method for cleaning a substrate before forming an epitaxial layer, only SC-1 + SC-2 cleaning is performed, and the purpose of the cleaning is to remove contamination and particles (Patent Document 1). However, even if such a cleaning method is applied to a substrate injected with carbon-containing ions, there is a problem that contamination and particle removal are not sufficient.
また、特許文献２には、ＳＯＩ基板の製造方法において、基板に水素イオンを注入する前に、ＳＣ−1洗浄＋ＳＣ−２洗浄、ＨＦ洗浄＋Ｏ３洗浄を組み合わせる洗浄が開示されているが、これは水素イオン注入前に洗浄する方法であり、炭素を含むイオンを注入した後の洗浄方法については何ら記載がない。 Further, Patent Document 2 discloses a method of manufacturing an SOI substrate, which is a combination of SC-1 cleaning + SC-2 cleaning and HF cleaning + O3 cleaning before injecting hydrogen ions into the substrate. It is a method of cleaning before hydrogen ion injection, and there is no description about a cleaning method after injection of carbon-containing ions.
エピタキシャル層形成前にシリコン基板に炭素を含むイオンを注入した場合、ゲッタリング能力が高まる一方で、イオン注入工程によって生じる汚染の増大及び炭素を含んだパーティクルの増加により、その後のエピタキシャル成長での汚染拡散及びエピ欠陥発生等の問題が生じることが判明した。具体的には、シリコン基板に炭素を含むイオンを注入した後、Ａｌ汚染を始め、Ｍｏ、Ｎｂ汚染及び、Ｃ系のパーティクルが含まれていることが判った。そして、近年になって、デバイスの高品質化が進み、このような基板品質では、デバイスでの特性不良、特に白傷不良が発生することが判った。 When carbon-containing ions are implanted into the silicon substrate before the epitaxial layer is formed, the gettering ability is enhanced, while the increase in contamination caused by the ion implantation process and the increase in carbon-containing particles causes contamination diffusion in the subsequent epitaxial growth. And it was found that problems such as the occurrence of epi defects occur. Specifically, after injecting carbon-containing ions into the silicon substrate, it was found that Al contamination, Mo, Nb contamination, and C-based particles were contained. Then, in recent years, it has been found that the quality of devices has been improved, and that such substrate quality causes poor characteristics of devices, especially white scratches.
本発明は、上記問題点に鑑みてなされたものであって、炭素を含むイオンの注入によりゲッタリング能力を高めると共に、エピタキシャル層形成前に、Ａｌ、Ｍｏ、Ｎｂ等汚染除去の難しい元素の汚染低減及び、ＥＰ欠陥の起点となるＣ系のパーティクル低減ができ、エピタキシャル成長後に汚染拡散及びエピ欠陥の発生が抑制されたシリコンエピタキシャルウェーハを製造することが可能なエピタキシャルウェーハの製造方法を提供することを目的とする。 The present invention has been made in view of the above problems, and the gettering ability is enhanced by injecting ions containing carbon, and contamination of elements such as Al, Mo, and Nb that are difficult to remove before forming an epitaxial layer is contaminated. To provide a method for producing an epitaxial wafer, which can reduce C-based particles which are the starting points of EP defects and can produce a silicon epitaxial wafer in which contamination diffusion and occurrence of epi defects are suppressed after epitaxial growth. The purpose.
上記課題を解決するために、本発明は、シリコン基板上にエピタキシャル層を形成するシリコンエピタキシャルウェーハの製造方法であって、前記シリコン基板に、炭素を含むイオンを注入した後、オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程と、ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程とを組み合わせることにより、前記シリコン基板の表面を洗浄し、その後、前記シリコン基板上に前記エピタキシャル層を形成することを特徴とするシリコンエピタキシャルウェーハの製造方法を提供する。 In order to solve the above problems, the present invention is a method for manufacturing a silicon epitaxial wafer in which an epitaxial layer is formed on a silicon substrate. After injecting carbon-containing ions into the silicon substrate, cleaning with ozone water and fluffing are performed. By combining the cleaning steps performed in the order of acid cleaning and ozone water cleaning and the cleaning steps performed in the order of SC-1 cleaning, SC-2 cleaning, and ozone water cleaning, the surface of the silicon substrate is cleaned, and then Provided is a method for manufacturing a silicon epitaxial wafer, which comprises forming the epitaxial layer on the silicon substrate.
このようなシリコンエピタキシャルウェーハの製造方法であれば、炭素を含むイオンの注入によりゲッタリング能力を高めると共に、Ａｌ、Ｍｏ、Ｎｂ等汚染除去の難しい元素の汚染低減及び、ＥＰ欠陥の起点となるＣ系のパーティクル低減ができ、エピタキシャル成長後に汚染拡散及びエピ欠陥の発生が抑制されたシリコンエピタキシャルウェーハを製造することができる。 In such a method for manufacturing a silicon epitaxial wafer, the gettering ability is enhanced by injecting ions containing carbon, the contamination of elements such as Al, Mo, and Nb that are difficult to remove is reduced, and C, which is the starting point of EP defects, is used. It is possible to manufacture a silicon epitaxial wafer in which the particles of the system can be reduced and the generation of contamination diffusion and epi-defects is suppressed after the epitaxial growth.
またこの場合、前記炭素を含むイオン注入を、炭素イオン又はＣ３Ｈ５イオンを注入することにより行うことが好ましい。 Also in this case, the ion implantation comprising the carbon, it is preferable to carry out by implanting carbon ions or C 3 H 5 ion.
このような炭素を含むイオンを注入することにより、エピタキシャルウェーハのゲッタリング能力を、確実に向上させることができる。 By injecting such carbon-containing ions, the gettering ability of the epitaxial wafer can be reliably improved.
また、この場合、前記オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程と、前記ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程とを、交互に繰り返し行うことが好ましい。 Further, in this case, the cleaning steps performed in the order of ozone water cleaning, hydrofluoric acid cleaning, and ozone water cleaning and the cleaning steps performed in the order of SC-1 cleaning, SC-2 cleaning, and ozone water cleaning are alternately performed. It is preferable to repeat the process.
このように洗浄することで、高い汚染レベルであっても、エピタキシャル層形成前に、汚染低減及びパーティクル低減を確実に行うことができる By cleaning in this way, it is possible to reliably reduce contamination and particles before forming the epitaxial layer even at a high contamination level.
また本発明では、シリコン基板上にエピタキシャル層を有するシリコンエピタキシャルウェーハであって、前記シリコン基板は、炭素を含むイオンが注入されたイオン注入層を有し、前記エピタキシャル層表面のＡｌ汚染量が１×１０９ａｔｏｍｓ／ｃｍ２以下、０．１２μｍ以上のエピタキシャル欠陥が２０個／ｗａｆｅｒ以下であることを特徴とするシリコンエピタキシャルウェーハを提供する。 Further, in the present invention, the silicon epitaxial wafer has an epitaxial layer on the silicon substrate, the silicon substrate has an ion implantation layer in which ions containing carbon are implanted, and the amount of Al contamination on the surface of the epitaxial layer is 1. Provided is a silicon epitaxial wafer characterized in that the number of epitaxial defects of × 10 9 atoms / cm 2 or less and 0.12 μm or more is 20 pieces / wafer or less.
このようなＡｌ汚染やエピタキシャル欠陥が低減されたシリコンエピタキシャルウェーハであれば、ＣＣＤ、ＣＭＯＳイメージセンサ等の半導体装置の基板として用いた場合に、白傷の発生を低減することが可能となる。 A silicon epitaxial wafer in which such Al contamination and epitaxial defects are reduced can reduce the occurrence of white scratches when used as a substrate for a semiconductor device such as a CCD or a CMOS image sensor.
本発明のシリコンエピタキシャルウェーハの製造方法であれば、炭素を含むイオンの注入によりゲッタリング能力を高めると共に、エピタキシャル層形成前に、Ａｌ、Ｍｏ、Ｎｂ等汚染除去の難しい元素の汚染低減及び、ＥＰ欠陥の起点となるＣ系のパーティクル低減をすることができ、エピタキシャル成長での汚染拡散及びエピ欠陥の発生が抑制された、高品質なシリコンエピタキシャルウェーハを製造することが可能となる。 In the method for producing a silicon epitaxial wafer of the present invention, the gettering ability is enhanced by injecting ions containing carbon, and before the epitaxial layer is formed, the contamination of elements such as Al, Mo, and Nb that are difficult to remove is reduced, and EP. It is possible to reduce the number of C-based particles that are the starting points of defects, and it is possible to manufacture a high-quality silicon epitaxial wafer in which contamination diffusion and occurrence of epi-defects in epitaxial growth are suppressed.
そのため、本発明のシリコンエピタキシャルウェーハであれば、ＣＣＤ、ＣＭＯＳイメージセンサ等の高品質、高歩留まりが要求される製品に使用された場合に、白傷不良を低減することができる。 Therefore, the silicon epitaxial wafer of the present invention can reduce white scratch defects when used in products such as CCDs and CMOS image sensors that require high quality and high yield.
上述したように、シリコン基板に炭素を含むイオンを注入した後では、Ａｌ汚染を始め、Ｍｏ、Ｎｂ汚染及び、Ｃ系のパーティクルが含まれており、このような基板品質では、デバイスでの特性不良、特に白傷不良を生じさせるという問題があった。 As described above, after injecting carbon-containing ions into a silicon substrate, Al contamination, Mo, Nb contamination, and C-based particles are contained, and such substrate quality is characteristic of the device. There was a problem of causing defects, especially white scratches.
そして、本発明者らは上記の問題を解決するために鋭意検討を重ねた結果、シリコン基板に炭素を含むイオンを注入した後に、エピタキシャル成長の前洗浄として、オゾン水洗浄で酸化膜を付けてその後フッ酸洗浄で酸化膜を除去すれば（Ｏ３＋ＨＦ洗浄）、深さ方向に形成された、汚染物質やパーティクルを除去することが可能であることを発見した。そして更に、ＳＣ−１＋ＳＣ−２洗浄を行うと、Ｏ３＋ＨＦ洗浄で取り切れない汚染物質やパーティクルも除去することができ、更に、各Ｏ３＋ＨＦ洗浄及びＳＣ−１＋ＳＣ−２洗浄の後にＯ３洗浄を加えることにより、基板表面が親水化され、パーティクルの再付着を防止することが可能になることを見出し、本発明に到達した。 As a result of diligent studies to solve the above problems, the present inventors inject carbon-containing ions into the silicon substrate, and then attach an oxide film by ozone water cleaning as a pre-cleaning for epitaxial growth. by removing the oxide film with hydrofluoric acid cleaning (O 3 + HF cleaning), which is formed in the depth direction, and found that it is possible to remove contaminants or particles. And further, when the SC-1 + SC-2 cleaning, O 3 + HF contaminants and particles that do not completely removed by washing can also be removed, further, O 3 after each O 3 + HF cleaning and SC-1 + SC-2 cleaning We have found that by adding cleaning, the surface of the substrate is made hydrophilic and it becomes possible to prevent reattachment of particles, and the present invention has been reached.
即ち、本発明は、シリコン基板上にエピタキシャル層を形成するシリコンエピタキシャルウェーハの製造方法であって、前記シリコン基板に、炭素を含むイオンを注入した後、オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程と、ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程とを組み合わせることにより、前記シリコン基板の表面を洗浄し、その後、前記シリコン基板上に前記エピタキシャル層を形成することを特徴とするシリコンエピタキシャルウェーハの製造方法を提供する。 That is, the present invention is a method for manufacturing a silicon epitaxial wafer in which an epitaxial layer is formed on a silicon substrate. After injecting carbon-containing ions into the silicon substrate, ozone water cleaning, hydrofluoric acid cleaning, and ozone water cleaning are performed. By combining the cleaning steps performed in this order with the cleaning steps performed in the order of SC-1 cleaning, SC-2 cleaning, and ozone water cleaning, the surface of the silicon substrate is cleaned, and then the silicon substrate is subjected to the cleaning step. Provided is a method for manufacturing a silicon epitaxial wafer, which comprises forming an epitaxial layer.
以下、本発明のシリコンエピタキシャルウェーハの製造方法を詳細に説明する。図１に、本発明のシリコンエピタキシャルウェーハの製造方法の一例を示したフロー図を示す。 Hereinafter, the method for manufacturing the silicon epitaxial wafer of the present invention will be described in detail. FIG. 1 shows a flow chart showing an example of a method for manufacturing a silicon epitaxial wafer of the present invention.
本発明のシリコンエピタキシャルウェーハの製造方法においては、まず、シリコン基板に炭素含むイオンを注入する（Ｓ１）。これによりゲッタリング能力を付与する。この時、炭素含むイオンとしては、炭素イオン又はＣ３Ｈ５イオンを注入することが望ましい。 In the method for manufacturing a silicon epitaxial wafer of the present invention, first, carbon-containing ions are injected into a silicon substrate (S1). This gives gettering ability. At this time, it is desirable to inject carbon ions or C 3 H 5 ions as carbon-containing ions.
次いで、オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程（Ｏ３＋ＨＦ＋Ｏ３洗浄工程ともいう）を行う（Ｓ２）。この洗浄工程は、連続した洗浄槽で行うことができ、最初のＯ３洗浄では酸化膜を形成し、次のＨＦ洗浄では酸化膜を除去し、次のＯ３洗浄では表面を親水性にする。 Next, a cleaning step (also referred to as O 3 + HF + O 3 cleaning step) in which ozone water cleaning, hydrofluoric acid cleaning, and ozone water cleaning are performed in this order is performed (S2). This washing step can be carried out in the cleaning tank continuous, in the first O 3 cleaning to form an oxide film, the following HF cleaning to remove the oxide film, to the hydrophilic surface in the next O 3 cleaning ..
この時、使用する洗浄液の条件は特に限定されないが、例えば、オゾン水は濃度５〜１５ｍｇ／Ｌ、流量１０〜１５Ｌ／ｍｉｎ、フッ酸は濃度１０〜２０％、流量２０〜３０Ｌ／ｍｉｎとすることができる。最初のオゾン水洗浄とＨＦ洗浄後のオゾン水洗浄は、同じ条件でも良いが、最初のオゾン水洗浄の濃度をＨＦ洗浄後のオゾン水洗浄の濃度よりも高くすることが好ましい。 At this time, the conditions of the cleaning liquid to be used are not particularly limited, but for example, ozone water has a concentration of 5 to 15 mg / L and a flow rate of 10 to 15 L / min, and hydrofluoric acid has a concentration of 10 to 20% and a flow rate of 20 to 30 L / min. be able to. The same conditions may be used for the initial ozone water cleaning and the ozone water cleaning after the HF cleaning, but it is preferable that the concentration of the initial ozone water cleaning is higher than the concentration of the ozone water cleaning after the HF cleaning.
次いで、ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程（以下、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程ともいう）を行う（Ｓ３）。この洗浄工程は、連続した洗浄槽で行うことができ、最初のＳＣ−１洗浄ではパーティクル除去を行い、次のＳＣ−２洗浄では汚染を除去し、最後のＯ３洗浄は表面を親水性にする。 Then, SC-1 cleaning, SC-2 cleaning, cleaning process performed in the order of ozone water cleaning (hereinafter, referred to as SC-1 + SC-2 + O 3 cleaning process) is performed (S3). This washing step can be carried out in the cleaning tank continuous, in the first SC-1 cleaning is performed removing particles, to remove contamination in the next SC-2 cleaning, final O 3 cleaning the surface hydrophilic To do.
この時の洗浄条件は特に限定されないが、例えば、ＳＣ−１洗浄は、アンモニア（ＮＨ３濃度２８％）、過酸化水素水（Ｈ２Ｏ２濃度３０％）、水の体積比（以下、ＮＨ４ＯＨ：Ｈ２Ｏ２：Ｈ２Ｏともいう）で１：１：５〜１：１：２０、流量２０〜３０Ｌ／ｍｉｎ、ＳＣ−２洗浄は、塩酸（ＨＣｌ濃度３６％）、過酸化水素水（Ｈ２Ｏ２濃度３０％）、水の体積比（以下、ＨＣｌ：Ｈ２Ｏ２：Ｈ２Ｏともいう）で１：１：５０〜２００、流量２０〜３０Ｌ／ｍｉｎとすることができる。また、オゾン水は濃度５〜１５ｍｇ／Ｌ、流量１０〜１５Ｌ／ｍｉｎとすることができる。 The cleaning conditions at this time are not particularly limited, but for example, in SC-1 cleaning, ammonia (NH 3 concentration 28%), hydrogen peroxide solution (H 2 O 2 concentration 30%), and water volume ratio (hereinafter, NH). 4 OH: H 2 O 2 : H 2 O) 1: 1: 5 to 1: 1: 20, flow rate 20 to 30 L / min, SC-2 washing with hydrochloric acid (HCl concentration 36%), hydrogen peroxide Hydrogen peroxide water (H 2 O 2 concentration 30%), water volume ratio (hereinafter, also referred to as HCl: H 2 O 2 : H 2 O) is 1: 1: 50 to 200, and the flow rate is 20 to 30 L / min. Can be done. Further, ozone water can have a concentration of 5 to 15 mg / L and a flow rate of 10 to 15 L / min.
（Ｓ２）のＯ３＋ＨＦ＋Ｏ３洗浄工程と（Ｓ３）のＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程とは、連続して行うこともでき、この場合の洗浄時間は、通常、同じになる。洗浄能力を確実なものとするためには、例えば、（Ｓ２）、（Ｓ３）中の各洗浄を１〜５分程度、好ましくは２〜３分実施することが望ましい。 The O 3 + HF + O 3 cleaning step of (S2) and the SC-1 + SC-2 + O 3 cleaning step of (S3) can be continuously performed, and the cleaning time in this case is usually the same. In order to ensure the cleaning ability, for example, it is desirable to carry out each cleaning in (S2) and (S3) for about 1 to 5 minutes, preferably 2 to 3 minutes.
（Ｓ２）の洗浄工程と（Ｓ３）の洗浄工程は、この順番に限定されず、逆であっても構わない。即ち、ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程の後に、オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程を行っても良い。 The cleaning step of (S2) and the cleaning step of (S3) are not limited to this order, and may be reversed. That is, after the cleaning steps of SC-1 cleaning, SC-2 cleaning, and ozone water cleaning, the cleaning steps of ozone water cleaning, hydrofluoric acid cleaning, and ozone water cleaning may be performed in this order.
また、（Ｓ２）、（Ｓ３）の各洗浄工程の間に純水でリンスする工程を入れることもできる。更に（Ｓ２）と（Ｓ３）を交互に繰り返すことにより、高い汚染レベルであっても汚染除去及びパーティクル除去をより確実に行うことができる。この場合、最大でも５回の繰り返し洗浄で十分であり、この時形成されるＯ３洗浄の酸化膜厚は、１ｎｍ程度である。 Further, a step of rinsing with pure water can be inserted between the cleaning steps of (S2) and (S3). Further, by alternately repeating (S2) and (S3), decontamination and particle removal can be performed more reliably even at a high contamination level. In this case, a sufficient five times repeatedly washed with maximum oxide thickness O 3 cleaning at this time is formed is about 1 nm.
上記（Ｓ２）中の最後のＯ３洗浄、（Ｓ３）中のＯ３洗浄において、１ｎｍ程度（例えば、０．５ｎｍ〜１．５ｎｍ）の薄い酸化膜を形成することで、エピタキシャル成長前の水素ベークで容易に除去することができ、エピタキシャル層を容易に形成することができるために好ましい。 Above (S2) the last O 3 cleaning in, the O 3 cleaning in (S3), approximately 1 nm (e.g., 0.5 nm to 1.5 nm) by forming a thin oxide film, before the epitaxial growth hydrogen baking It is preferable because it can be easily removed by the above method and the epitaxial layer can be easily formed.
次いで、シリコン基板上にエピタキシャル層を形成する（Ｓ４）。通常、水素ベークによりウェーハ表面の酸化膜を除去してから、エピタキシャル成長を行う。これにより、エピタキシャル層表面のＡｌ汚染が、１×１０９ａｔｏｍｓ／ｃｍ２以下、０．１２μｍ以上のエピタキシャル欠陥が、２０個／ｗａｆｅｒ以下のエピタキシャルウェーハを製造することができる。 Next, an epitaxial layer is formed on the silicon substrate (S4). Usually, the oxide film on the wafer surface is removed by hydrogen baking, and then epitaxial growth is performed. As a result, an epitaxial wafer having an Al contamination on the surface of the epitaxial layer of 1 × 10 9 atoms / cm 2 or less and an epitaxial defect of 0.12 μm or more of 20 wafers / wafer or less can be manufactured.
従って、本発明によれば、シリコン基板上にエピタキシャル層を有するシリコンエピタキシャルウェーハであって、前記シリコン基板は、炭素を含むイオンが注入されたイオン注入層を有し、前記エピタキシャル層表面のＡｌ汚染量が１×１０９ａｔｏｍｓ／ｃｍ２以下、０．１２μｍ以上のエピタキシャル欠陥が２０個／ｗａｆｅｒ以下であることを特徴とするシリコンエピタキシャルウェーハが提供される。 Therefore, according to the present invention, a silicon epitaxial wafer having an epitaxial layer on a silicon substrate, the silicon substrate has an ion-implanted layer in which ions containing carbon are implanted, and Al contamination on the surface of the epitaxial layer. Provided is a silicon epitaxial wafer having an amount of 1 × 10 9 atoms / cm 2 or less and 0.12 μm or more having 20 epitaxial defects / wafer or less.
以下、実施例及び比較例を示して本発明をより具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
（実施例１）
直径３００ｍｍ、抵抗率１０Ω・ｃｍのリンドープのシリコン単結晶基板を準備し、シリコン基板表面の０．１２μｍ以上のパーティクルを測定した。その結果、シリコン基板表面にはパーティクルは存在していないことが確認された（図２（Ａ））。
(Example 1)
A phosphorus-doped silicon single crystal substrate having a diameter of 300 mm and a resistivity of 10 Ω · cm was prepared, and particles of 0.12 μm or more on the surface of the silicon substrate were measured. As a result, it was confirmed that no particles were present on the surface of the silicon substrate (FIG. 2 (A)).
次に、シリコン基板に炭素イオン、又は、Ｃ３Ｈ５イオンを加速電圧８０ｋｅＶ、ドーズ量２．５×１０１５ａｔｏｍｓ／ｃｍ２でイオン注入を行い、イオン注入後の段階で同様にシリコン基板表面のパーティクル測定を行った。その結果、炭素イオンを注入した場合は１３７０個／ｗａｆｅｒ、Ｃ３Ｈ５イオンを注入した場合は１２４３個／ｗａｆｅｒとなった（図２（Ｂ））。 Next, carbon ions or C 3 H 5 ions are implanted into the silicon substrate at an accelerating voltage of 80 keV and a dose amount of 2.5 × 10 15 atoms / cm 2 , and the surface of the silicon substrate is similarly implanted after the ion implantation. Particle measurement was performed. As a result, 1370 pieces when injected carbon ions / Wafer, when injected with C 3 H 5 ion became 1243 pieces / Wafer (Fig 2 (B)).
そして、Ｏ３＋ＨＦ＋Ｏ３洗浄工程を、最初のＯ３洗浄が（濃度１０ｍｇ／Ｌ、流量１５Ｌ／ｍｉｎ、２ｍｉｎ）、ＨＦ洗浄が（濃度１５％、流量２５Ｌ／ｍｉｎ、２ｍｉｎ）、最後のＯ３洗浄が（濃度１０ｍｇ／Ｌ、流量１５Ｌ／ｍｉｎ、２ｍｉｎ）の条件で行い、その後、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程を、ＳＣ−１洗浄が（ＮＨ４ＯＨ：Ｈ２Ｏ２：Ｈ２Ｏ＝１：１：１０、流量２５Ｌ／ｍｉｎ、２ｍｉｎ）、ＳＣ−２洗浄が（ＨＣｌ：Ｈ２Ｏ２：Ｈ２Ｏ＝１：１：１００、流量２５Ｌ／ｍｉｎ、２ｍｉｎ）、Ｏ３洗浄が（濃度１０ｍｇ／Ｌ、流量１５Ｌ／ｍｉｎ、２ｍｉｎ）の条件で行った後、同様にシリコン基板表面のパーティクル測定を行った。その結果、炭素イオンを注入した場合は５個／ｗａｆｅｒ、Ｃ３Ｈ５イオンを注入した場合は７個／ｗａｆｅｒとなった。この結果を図２（Ｃ）に示す。 Then, in the O 3 + HF + O 3 cleaning step, the first O 3 cleaning (concentration 10 mg / L, flow rate 15 L / min, 2 min), the HF cleaning (concentration 15%, flow rate 25 L / min, 2 min), and the final O 3 Cleaning is performed under the conditions of (concentration 10 mg / L, flow rate 15 L / min, 2 min), and then the SC-1 + SC-2 + O 3 cleaning step is performed, and the SC-1 cleaning is performed (NH 4 OH: H 2 O 2 : H 2 O). = 1: 1:10, flow rate 25 L / min, 2 min), SC-2 cleaning (HCl: H 2 O 2 : H 2 O = 1: 1: 100, flow rate 25 L / min, 2 min), O 3 cleaning After performing under the conditions of (concentration 10 mg / L, flow rate 15 L / min, 2 min), particle measurement on the surface of the silicon substrate was performed in the same manner. As a result, when injected carbon ions 5 / Wafer, when injected a C 3 H 5 ion became 7 / Wafer. The result is shown in FIG. 2 (C).
以上により、このＯ３＋ＨＦ＋Ｏ３洗浄工程とＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程はそれぞれ１回のみの実施であるが、ＥＰ欠陥の原因となるシリコン基板表面のパーティクルがほとんどなくなっていることが判った。 From the above, it was found that the O 3 + HF + O 3 cleaning process and the SC-1 + SC-2 + O 3 cleaning process were performed only once, but the particles on the surface of the silicon substrate, which cause EP defects, were almost eliminated. ..
さらに、水素ベーク及び５μｍのエピタキシャル成長を行った後に、同様にしてＥＰ欠陥の評価を行った。その結果、２０個／ｗａｆｅｒ以下であった。 Further, after hydrogen baking and epitaxial growth of 5 μm, EP defects were evaluated in the same manner. As a result, the number was 20 / wafer or less.
（比較例１）
実施例１と同様にシリコン基板の準備、炭素イオン又はＣ３Ｈ５イオン注入をした後、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄のみを行い、洗浄後のシリコン基板表面のパーティクル測定を行った。その結果、炭素イオンを注入した場合は５４９個／ｗａｆｅｒ、Ｃ３Ｈ５イオンを注入した場合は４５６個／ｗａｆｅｒとなった（図２（Ｄ））。
(Comparative Example 1)
In the same manner as in Example 1, after preparing the silicon substrate and implanting carbon ions or C 3 H 5 ions, only SC-1 + SC-2 + O 3 cleaning was performed, and the particles on the surface of the silicon substrate after cleaning were measured. As a result, 549 when injected carbon ions pieces / Wafer, when injected with C 3 H 5 ion became 456 / Wafer (Fig 2 (D)).
このように、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄のみではシリコン基板表面のパーティクルを十分に除去することができなかった。また、このシリコン基板表面のパーティクルをＳＥＭで分析した結果、図３に示すように、炭素起因のパーティクルであることが確認された。炭素イオン又はＣ３Ｈ５イオン注入後の洗浄を行った後のパーティクルのＳＥＭ画像及びＳＥＭによる元素分析結果をそれぞれ図３（Ａ）、（Ｂ）に示す。 Thus, the only SC-1 + SC-2 + O 3 cleaning was not possible to sufficiently remove particles of silicon substrate surface. Further, as a result of analyzing the particles on the surface of the silicon substrate by SEM, it was confirmed that the particles were caused by carbon as shown in FIG. Carbon ions or C 3 H 5 ion implantation respectively diagrams washed went after particles of the SEM image and the elemental analysis by SEM after 3 (A), shown in (B).
（実施例２）
イオン注入元素を炭素イオンとし、実施例１と同じ方法でシリコン基板の準備、イオン注入、Ｏ３＋ＨＦ＋Ｏ３洗浄工程とＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程を行った後、ＩＣＰ−ＭＳでＡｌ汚染の定量分析を行った。このＡｌ汚染の評価では、Ｏ３＋ＨＦ＋Ｏ３洗浄工程とＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程を交互に１回〜５回繰り返して行ったときのそれぞれの定量分析を行った。この結果を図４に示す。
(Example 2)
Using carbon ions as the ion-implanted element, the silicon substrate is prepared, ion-implanted, O 3 + HF + O 3 cleaning step and SC-1 + SC-2 + O 3 cleaning step are performed in the same manner as in Example 1, and then Al contamination is performed by ICP-MS. Quantitative analysis was performed. In the evaluation of this Al contamination, each quantitative analysis was performed when the O 3 + HF + O 3 cleaning step and the SC-1 + SC-2 + O 3 cleaning step were alternately repeated 1 to 5 times. The result is shown in FIG.
図４から分かるように、Ｏ３＋ＨＦ＋Ｏ３洗浄とＳＣ−１＋ＳＣ−２＋Ｏ３洗浄とを少なくても１回以上行うことにより、Ａｌ汚染量は１×１０９ａｔｏｍｓ／ｃｍ２以下となった。また、これらの洗浄を繰り返すことで、Ａｌ汚染量はより減少した。そして、Ｏ３＋ＨＦ＋Ｏ３洗浄工程とＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程を実施した後、水素ベーク及び５μｍのエピタキシャル成長を行った後でも同様にしてエピタキシャル表面のＡｌ汚染の定量分析を行った。その結果、エピタキシャル成長前と同等のレベルであることが確認された。 As can be seen from FIG. 4, by performing O 3 + HF + O 3 cleaning and SC-1 + SC-2 + O 3 cleaning at least once, the amount of Al contamination was 1 × 10 9 atoms / cm 2 or less. Moreover, by repeating these washings, the amount of Al contamination was further reduced. Then, after performing the O 3 + HF + O 3 cleaning step and the SC-1 + SC-2 + O 3 cleaning step, the quantitative analysis of Al contamination on the epitaxial surface was performed in the same manner even after performing hydrogen baking and epitaxial growth of 5 μm. As a result, it was confirmed that the level was the same as before the epitaxial growth.
（比較例２）
イオン注入後の洗浄を、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程を１回のみとした以外は、実施例２と同じ方法でＡｌ汚染の定量分析を行った。この結果を図４に示す。ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄工程だけでは、１×１０１０ａｔｏｍｓ／ｃｍ２を超える汚染量となった。この時の、ＳＣ−１、ＳＣ−２、Ｏ３洗浄の条件は、実施例１の条件と同じで実施した。
(Comparative Example 2)
The washing after the ion implantation, except for using only once SC-1 + SC-2 + O 3 cleaning step was performed a quantitative analysis of Al contamination in the same manner as in Example 2. The result is shown in FIG. Alone SC-1 + SC-2 + O 3 cleaning process was the amount of contamination exceeding 1 × 10 10 atoms / cm 2 . At this time, SC-1, SC-2 , O 3 washing conditions were performed the same as the conditions of Example 1.
また、ＳＣ−１＋ＳＣ−２＋Ｏ３洗浄を実施した後、水素ベーク及び５μｍのエピタキシャル成長を行った後でも同様にして、エピタキシャル表面のＡｌ汚染の定量分析を行った。その結果、エピタキシャル成長前と同等のレベルであることが確認された。 Furthermore, after implementing the SC-1 + SC-2 + O 3 cleaning, in the same manner even after the epitaxial growth of the hydrogen bake and 5 [mu] m, it was subjected to quantitative analysis of Al contamination of the epitaxial surface. As a result, it was confirmed that the level was the same as before the epitaxial growth.
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
The present invention is not limited to the above embodiment. The above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. It is included in the technical scope of the invention.
Claims (3)
前記シリコン基板に、炭素を含むイオンを注入した後、
オゾン水洗浄、フッ酸洗浄、オゾン水洗浄の順で行う洗浄工程と、ＳＣ−１洗浄、ＳＣ−２洗浄、オゾン水洗浄の順で行う洗浄工程とを組み合わせることにより、前記シリコン基板の表面を洗浄し、その後、
前記シリコン基板上に前記エピタキシャル層を形成することを特徴とするシリコンエピタキシャルウェーハの製造方法。 A method for manufacturing a silicon epitaxial wafer in which an epitaxial layer is formed on a silicon substrate.
After injecting carbon-containing ions into the silicon substrate,
By combining the cleaning steps performed in the order of ozone water cleaning, hydrofluoric acid cleaning, and ozone water cleaning and the cleaning steps performed in the order of SC-1 cleaning, SC-2 cleaning, and ozone water cleaning, the surface of the silicon substrate can be cleaned. Wash and then
A method for manufacturing a silicon epitaxial wafer, which comprises forming the epitaxial layer on the silicon substrate.
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