JPH0298134A - Pretreatment process for semiconductor wafer life time measurement - Google Patents
Pretreatment process for semiconductor wafer life time measurementInfo
- Publication number
- JPH0298134A JPH0298134A JP25068988A JP25068988A JPH0298134A JP H0298134 A JPH0298134 A JP H0298134A JP 25068988 A JP25068988 A JP 25068988A JP 25068988 A JP25068988 A JP 25068988A JP H0298134 A JPH0298134 A JP H0298134A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor wafer
- lifetime
- cleaning
- wafer
- cleaning solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 28
- 238000005259 measurement Methods 0.000 title claims description 10
- 238000000034 method Methods 0.000 title description 12
- 238000004140 cleaning Methods 0.000 claims abstract description 26
- 239000012535 impurity Substances 0.000 claims abstract description 10
- 229910052751 metal Inorganic materials 0.000 claims abstract description 10
- 239000011521 glass Substances 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims abstract description 6
- 235000012431 wafers Nutrition 0.000 claims description 41
- 238000002203 pretreatment Methods 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims 1
- 238000005215 recombination Methods 0.000 abstract description 8
- 230000006798 recombination Effects 0.000 abstract description 8
- 230000007423 decrease Effects 0.000 abstract description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 abstract 1
- 235000011114 ammonium hydroxide Nutrition 0.000 abstract 1
- 238000009826 distribution Methods 0.000 description 8
- 238000011109 contamination Methods 0.000 description 5
- 239000000969 carrier Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- JHWIEAWILPSRMU-UHFFFAOYSA-N 2-methyl-3-pyrimidin-4-ylpropanoic acid Chemical compound OC(=O)C(C)CC1=CC=NC=N1 JHWIEAWILPSRMU-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 241000257465 Echinoidea Species 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- -1 dichromate ions Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005036 potential barrier Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002335 surface treatment layer Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Cleaning Or Drying Semiconductors (AREA)
Abstract
Description
【発明の詳細な説明】
「産業上の利用分野」
この発明は、半導体ウェハのライフタイムを測定する前
に施されるウェハの表面の処理法に関するものである。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for treating the surface of a semiconductor wafer before measuring its lifetime.
「従来の技術」
一般に、半導体ウェハのライフタイムを測定する場合、
実測されるライフタイムτｍは半導体結晶の純度や結欠
陥等で決まるバルク（結晶母体）のライフタイムτｂだ
けでなく半導体ウェハの汚れや表面加工層等によって決
まるライフタイム値成分τＳが関与するもので、
１／τ悶＝１／τｂ＋ｌ／τＳ
なる関係があり、τＳは半導体ウェハの表面近傍で起こ
る表面再結合速度Ｓに関係する。このＳの値は、ウェハ
の表面に自然酸化膜があると、大きくなり、このように
Ｓの値が大きくなると、ウェハ自体のライフタイムτｍ
の値が小さくなって測定不能になると共にライフタイム
τｍの面内分布が隠されてしまう。"Conventional technology" Generally, when measuring the lifetime of semiconductor wafers,
The actually measured lifetime τm involves not only the lifetime τb of the bulk (crystal matrix), which is determined by the purity of the semiconductor crystal and defects, but also the lifetime value component τS, which is determined by the contamination of the semiconductor wafer, the surface treatment layer, etc. , 1/τ=1/τb+l/τS, where τS is related to the surface recombination speed S that occurs near the surface of the semiconductor wafer. The value of S increases when there is a natural oxide film on the surface of the wafer, and when the value of S increases in this way, the lifetime of the wafer itself τm
The value of becomes small and becomes unmeasurable, and the in-plane distribution of the lifetime τm is hidden.
そこで、半導体ウェハのτｍを測定するにあたっては、
表面再結合速度Ｓを低減する必要がある。Therefore, when measuring τm of a semiconductor wafer,
It is necessary to reduce the surface recombination rate S.
そのために、従来、Ｎ型の半導体ウェハに対してその表
面に正の電荷膜をつける処理（Ｎ ＣＣ法）を施し、Ｐ
型の半導体ウェハに対してその表面に負の電荷膜をつけ
る処理ｃｐ ｃ ｃ法）を施し、半導体ウェハの表面近
傍にポテンシャルバリヤを形成することによって半導体
ウェハの表面再結合速度Ｓを減少させる方法や、希ＨＦ
溶液中に半導体ウェハを浸し、表面の自然酸化膜を除去
する方法が採られていた。To this end, conventionally, N-type semiconductor wafers are subjected to a process (NCC method) in which a positively charged film is applied to the surface of the N-type semiconductor wafer.
A method of reducing the surface recombination speed S of a semiconductor wafer by subjecting a type of semiconductor wafer to a process of applying a negative charge film to its surface (CPC method) to form a potential barrier near the surface of the semiconductor wafer. Ya, Nozomi HF
The method used was to immerse the semiconductor wafer in a solution and remove the natural oxide film on the surface.
「発明が解決しようとする課題」
しかしながら、上記電荷膜をつける方法にあっては、ウ
ェハの表面が汚染されるので、ライフタイム測定後に洗
浄する必要があり、特に、Ｐ型の場合のＮＣＣ法ではウ
ェハを重クロム酸ナトリウム１％溶液で煮沸しなければ
ならないため、表面に重クロム酸イオンが付着する。ク
ロムを含有した溶液を使用することは処置を誤ると、他
の洗浄ウェハの汚染等の心配があり望ましいものではな
かった。``Problems to be Solved by the Invention'' However, in the above method of applying a charge film, the surface of the wafer is contaminated, so it is necessary to clean it after lifetime measurement. Since the wafer must be boiled in a 1% sodium dichromate solution, dichromate ions adhere to the surface. It is not desirable to use a solution containing chromium because there is a risk of contamination of other cleaned wafers if the procedure is incorrect.
また、希ＨＦ溶液を用いて自然酸化膜を除去する方法に
あっては、第４図に示すように、処理後の時間と共に成
長する自然酸化膜の影響のため、同一場所のライフタイ
ムの値が減少する。このため、ウェハ表面の細かい面内
分布の測定は経時変化の影響がでるため困難なしのであ
った。In addition, in the method of removing the natural oxide film using a dilute HF solution, as shown in Figure 4, due to the influence of the natural oxide film that grows over time after treatment, the lifetime value at the same location is decreases. Therefore, it is not difficult to measure the fine in-plane distribution on the wafer surface because it is affected by changes over time.
「発明の目的」
この発明は上記事情に鑑みてなされた乙のであり、その
目的とするところは、ライフタイムの測定に対し、ライ
フタイムの経時変化がほとんどない安定したウェハの表
面を得ることができかつウェハ表面の汚染の非常に少な
い半導体ウェハのライフタイム測定における前処理法を
提供することにある。"Purpose of the Invention" This invention was made in view of the above circumstances, and its purpose is to obtain a stable wafer surface with almost no change in lifetime over time when measuring lifetime. It is an object of the present invention to provide a pretreatment method for lifetime measurement of semiconductor wafers that is possible and causes very little contamination on the wafer surface.
「課題を解決するための手段」
そこで、本発明者等が、上記課題を解決すべく鋭意研究
を重ねたところ、次のような知見を得るに至った。"Means for Solving the Problems" Therefore, the inventors of the present invention conducted extensive research to solve the above problems, and as a result, they came to the following knowledge.
すなわち、ガラスを微少量エツチングするＮＨ４０ＨＺ
Ｈｔ Ｏを系の洗浄液を用い、Ｂ、ＡＱＳＮａ。In other words, NH40HZ etches a small amount of glass.
B, AQSNa using HtO-based wash solution.
Ｋ、Ｃａ、Ｍｇ、Ｂａ等の金属元素を不純物として含む
ガラスの容器で半導体ウェハを洗浄すると、少数キャリ
アの再結合ライフタイムにとって、極めて安定なウェハ
表面を得られることが判明した。It has been found that cleaning a semiconductor wafer in a glass container containing impurities such as metal elements such as K, Ca, Mg, and Ba provides a wafer surface that is extremely stable for the recombination lifetime of minority carriers.
これはガラスを僅かに侵ずＮ Ｈ−ＯＨ／ Ｈｔ Ｏ！
系の洗浄により、ＮＣＣ法とは比べものにならない低レ
ベルの汚染物質（Ｂ、ＡＱｓ Ｎａ５Ｋ、Ｃａ。This does not attack the glass slightly and is N H-OH/ Ht O!
Due to the cleaning of the system, low levels of contaminants (B, AQs Na5K, Ca.
Ｍｇ、１３３等の金属元素）が洗浄時に成長する自然酸
化膜中に入り、少数キャリアの表面再結合速度Ｓを誠ら
ず安定した表面酸化膜を形成するものである。この表面
酸化膜は数ケ月に亙り安定な状態が持続することが確認
された。したがって、１時間程度の時間を要するライフ
タイムの詳細な面内分布測定の間の経時変化は全く無視
できる。Metal elements such as Mg, 133, etc.) enter the natural oxide film that grows during cleaning, and form a surface oxide film with a stable surface recombination rate S of minority carriers. It was confirmed that this surface oxide film remained stable for several months. Therefore, changes over time during the detailed in-plane distribution measurement of the lifetime, which takes about one hour, can be completely ignored.
この発明は上記知見に基づいて構成したもので、表面に
熱酸化膜が被覆されていない半導体ウェハを、金属元素
、特にＢ １Ａ Ｑｓ Ｎ ８１Ｋ −ＣａＮ Ｍ ｇ
ｓＢａの少なくともいずれか一つを不純物として含むガ
ラス容器に入れられたＮ １４４０１−１ ／ト１ｔｏ
ｔ系の洗浄液で洗浄したらのである。また、表面再結合
速度Ｓを減らず安定した表面酸化膜を形成するには、洗
浄温度を７０〜９０℃、洗浄時間を３分以上にするのが
望ましい。さらに、洗浄時にウェハ表面に付着した微少
量汚染のレベルは、研磨後のレベルと大差はなく、通常
のＲＣＡ系洗浄により簡単に除去できる。したがって、
ウェハ製造各工程での抜き取り検査が可能である。The present invention was constructed based on the above findings, and a semiconductor wafer whose surface is not coated with a thermal oxide film is treated with a metal element, particularly B 1A Qs N 81K -CaN M g
N 14401-1/t1to placed in a glass container containing at least one of sBa as an impurity
I washed it with a T-based cleaning solution. Further, in order to form a stable surface oxide film without reducing the surface recombination rate S, it is desirable that the cleaning temperature be 70 to 90° C. and the cleaning time be 3 minutes or more. Furthermore, the level of minute contamination that adheres to the wafer surface during cleaning is not much different from the level after polishing, and can be easily removed by normal RCA cleaning. therefore,
Sampling inspections are possible at each wafer manufacturing process.
なお、洗浄容器としては不純物を含まない石英ガラス、
ＮＨ，ＯＨ／Ｈ！Ｏ，系洗浄に侵されないテフロンは使
用不可能である。The cleaning container is made of quartz glass that does not contain impurities.
NH, OH/H! O. Teflon, which is not attacked by system cleaning, cannot be used.
「作用」
この発明の半導体ウェハのライフタイム測定における前
処理法にあっては、ガラス容器に不純物として含まれる
金属元素がＮ Ｉ−１、ＯＩ（／ Ｈｔ Ｏを系の洗浄
液中に溶出して、洗浄時に成長する自然酸化膜中に入り
、少数キャリ゛アの表面再結合速度Ｓを減らず安定した
表面酸化膜を形成する。"Operation" In the pretreatment method for lifetime measurement of semiconductor wafers of the present invention, metal elements contained as impurities in the glass container elute NI-1, OI (/HtO) into the cleaning solution of the system. , enters the natural oxide film that grows during cleaning and forms a stable surface oxide film without reducing the surface recombination rate S of minority carriers.
「実施例」
以下、この発明の半導体ウニノーのライフタイム測定に
おける前処理法の一実施例を説明する。"Example" Hereinafter, an example of the pretreatment method for measuring the lifetime of semiconductor Uninow according to the present invention will be described.
市販のガラスピーカにＮ Ｈ４０Ｈ／ Ｈｔ Ｏを系の
洗浄液を入れ、この洗浄液中で半面だけにレーザダメー
ジを与えたシリコンウエノ１を洗浄した。A commercially available glass speaker was filled with a cleaning solution based on N H40H/Ht 2 O, and silicon wafer 1, which had undergone laser damage on only half of its surface, was cleaned in this cleaning solution.
迭ｊ１に井−
洗浄温度・・・８０℃
洗浄時間・・・３０分
また、このガラスピーカには、Ｂ、 Ａ１２％ Ｎａ５
Ｋ、Ｃａ、Ｍｇ、Ｂａ等の金属不純物質が含まれている
。Washing temperature: 80°C Washing time: 30 minutes Also, this glass speaker contains B, A12% Na5
Contains metal impurities such as K, Ca, Mg, and Ba.
そして、このウェハのライフタイムの測定結果を第１図
に示す。この図から明らかなよう１こ、ライフタイムが
経時変化の影響を受けて（１なｔｌことが判る。The results of measuring the lifetime of this wafer are shown in FIG. As is clear from this figure, the lifetime is affected by changes over time (1 tl).
このように、ライフタイムが経時変化の影響を受けない
ので、１時間以上の時間を要するライフタイムの面内分
布の測定を行うことができる。In this way, since the lifetime is not affected by changes over time, it is possible to measure the in-plane distribution of the lifetime, which requires more than one hour.
このライフタイムの面内分布の測定結果を第２図および
第３図に示す。これらの図に示すよう１こ、レーザダメ
ージが与えられた右半面および与えられていない左半面
のいずれにおいても経時変化の影響を受けないウェハ本
来のライフタイムの面内分布が得られる。The measurement results of this in-plane lifetime distribution are shown in FIGS. 2 and 3. As shown in these figures, the in-plane distribution of the original lifetime of the wafer, which is not affected by changes over time, can be obtained both on the right half surface where laser damage has been applied and on the left half surface where laser damage has not been applied.
なお、第２図において、黒塗りの四角はウェハの各部分
のう゛イフタイムの長さを模式的に表したものであり、
面積が大きい程ライフタイムの長さが長いことを意味す
る。また第３図は第２図に対応させて、ライフタイムの
長さを立体的に表したものであり、高さが高い程ライフ
タイムの長さが長いことを意味する。In addition, in Fig. 2, the black squares schematically represent the lifetime length of each part of the wafer.
The larger the area, the longer the lifetime. In addition, FIG. 3 is a three-dimensional representation of the lifetime length corresponding to FIG. 2, and the higher the height, the longer the lifetime length.
「発明の効果」
以上説明しｉこように、この発明の半導体ウェハのライ
フタイム測定における前処理法によれば、ライフタイム
の経時変化がほとんどない安定したウェハの表面を得る
ことができるので、ライフタイムの細かい面内分布を得
ることができる。"Effects of the Invention" As explained above, according to the pretreatment method for measuring the lifetime of semiconductor wafers of the present invention, it is possible to obtain a stable wafer surface with almost no change in lifetime over time. A detailed in-plane distribution of lifetime can be obtained.
また、洗浄時にウェハ表面に付着した微少量汚染のレベ
ルは、研磨後のレベルと大差はなく、簡単な洗浄により
除去できる。したがって、エツチング工程以降のウェハ
製造各工程での抜き取り検査を行い、再び製造ラインに
戻すことが可能であるので、ウェハを有効に利用するこ
とができる。Furthermore, the level of minute contamination that adheres to the wafer surface during cleaning is not much different from the level after polishing, and can be removed by simple cleaning. Therefore, it is possible to conduct a sampling inspection at each wafer manufacturing process after the etching process and return the wafer to the manufacturing line, so that the wafer can be used effectively.
第１図および第３図はこの発明の半導体ウニ／）のライ
フタイム測定における前処理法を説明するためのもので
あり、第１図は前処理後のライフタイムの経時変化を示
すグラフ、第２図および第３図はそれぞれライフタイム
の面内分布を模式的に示す図、第４図はＨＦ溶液で処理
後のライフタイムの経時変化を示すグラフである。Figures 1 and 3 are for explaining the pretreatment method for measuring the lifetime of semiconductor sea urchins/) according to the present invention. FIG. 2 and FIG. 3 are diagrams each schematically showing the in-plane distribution of lifetime, and FIG. 4 is a graph showing the change over time of lifetime after treatment with an HF solution.
Claims (4)
を、金属元素を不純物として含むガラス容器に入れられ
たＮＨ＿４ＯＨ／Ｈ＿２Ｏ＿２系の洗浄液で洗浄したこ
とを特徴とする半導体ウェハのライフタイム測定におけ
る前処理法。(1) In the lifetime measurement of a semiconductor wafer, which is characterized in that a semiconductor wafer whose surface is not coated with a thermal oxide film is cleaned with an NH_4OH/H_2O_2-based cleaning solution placed in a glass container containing a metal element as an impurity. Pretreatment method.
、Ｃａ、Ｍｇ、Ｂａの少なくともいずれか一つであるこ
とを特徴とする請求項１に記載の半導体ウェハのライフ
タイム測定における前処理法。(2) Metal elements as impurities include B, Al, Na, K
2. The pretreatment method for lifetime measurement of semiconductor wafers according to claim 1, wherein the pretreatment method is at least one of Ca, Mg, and Ba.
する請求項１または２に記載の半導体ウェハのライフタ
イム測定における前処理法。(3) The pretreatment method for lifetime measurement of semiconductor wafers according to claim 1 or 2, wherein the temperature of the cleaning liquid is 70 to 90°C.
項１〜３のいずれか１項に記載の半導体ウェハのライフ
タイム測定における前処理法。(4) The pretreatment method for lifetime measurement of semiconductor wafers according to any one of claims 1 to 3, wherein the cleaning time is 3 minutes or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25068988A JPH0298134A (en) | 1988-10-04 | 1988-10-04 | Pretreatment process for semiconductor wafer life time measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25068988A JPH0298134A (en) | 1988-10-04 | 1988-10-04 | Pretreatment process for semiconductor wafer life time measurement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0298134A true JPH0298134A (en) | 1990-04-10 |
Family
ID=17211582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25068988A Pending JPH0298134A (en) | 1988-10-04 | 1988-10-04 | Pretreatment process for semiconductor wafer life time measurement |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0298134A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0883828A (en) * | 1994-09-09 | 1996-03-26 | Mitsubishi Materials Corp | Measuring method of internal defect of semiconductor wafer, and controlling method of thermal oxidation furnace using the same |
-
1988
- 1988-10-04 JP JP25068988A patent/JPH0298134A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0883828A (en) * | 1994-09-09 | 1996-03-26 | Mitsubishi Materials Corp | Measuring method of internal defect of semiconductor wafer, and controlling method of thermal oxidation furnace using the same |
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