JPH06349923A - Evaluation method of silicon wafer and breakdown strength of oxide film thereof - Google Patents
Evaluation method of silicon wafer and breakdown strength of oxide film thereofInfo
- Publication number
- JPH06349923A JPH06349923A JP15796593A JP15796593A JPH06349923A JP H06349923 A JPH06349923 A JP H06349923A JP 15796593 A JP15796593 A JP 15796593A JP 15796593 A JP15796593 A JP 15796593A JP H06349923 A JPH06349923 A JP H06349923A
- Authority
- JP
- Japan
- Prior art keywords
- silicon wafer
- oxide film
- laser
- defective
- density
- 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.)
- Granted
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 37
- 239000010703 silicon Substances 0.000 title claims abstract description 37
- 230000015556 catabolic process Effects 0.000 title claims abstract description 22
- 238000011156 evaluation Methods 0.000 title description 3
- 230000002950 deficient Effects 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 7
- 239000002344 surface layer Substances 0.000 claims description 8
- 239000004065 semiconductor Substances 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000001364 causal effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明はシリコンウェーハの酸
化膜耐圧に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide film breakdown voltage of a silicon wafer.
【０００２】[0002]
【従来の技術】シリコンウェーハの表層には各種のデバ
イスが組み込まれるが、各デバイスが電気的に良好に作
動するためには、その酸化膜耐圧の値が基準値を越えて
いる必要がある。しかるに従来よりデバイスの酸化膜耐
圧に影響を及ぼす因子については必ずしも十分に解明さ
れておらず、このため従来は実際に酸化膜耐圧測定用の
ＭＯＳキャパシターを作成して、実際に酸化膜耐圧を測
定していた。2. Description of the Related Art Various devices are incorporated in the surface layer of a silicon wafer. However, in order for each device to operate electrically favorably, its oxide film breakdown voltage must exceed a reference value. However, the factors affecting the oxide film breakdown voltage of the device have not been sufficiently clarified so far, and therefore, conventionally, a MOS capacitor for measuring the oxide film breakdown voltage was actually created and the oxide film breakdown voltage was actually measured. Was.
【０００３】[0003]
【発明が解決しようとする課題】しかるに上記従来の酸
化膜耐圧の評価方法は、実際に酸化膜耐圧測定用のＭＯ
Ｓキャパシターを作成して酸化膜耐圧を測定するもので
あるから、長時間を要するという問題点がある。すなわ
ち素子作成から酸化膜耐圧測定までに要する時間を単純
に加算しても２０時間程度を要し、実際には各種の準備
作業等があるために１週間程度を要していた。したがっ
て本発明は、簡易且つ迅速に酸化膜耐圧を評価すること
ができ、したがって評価に要するコストが著しく低廉な
シリコンウェーハの酸化膜耐圧の評価方法を提供し、併
せて酸化膜耐圧が十分に良好なシリコンウェーハを提供
することを目的とする。However, the above-mentioned conventional method for evaluating the withstand voltage of the oxide film is actually used for the MO for measuring the withstand voltage of the oxide film.
Since the S capacitor is formed to measure the oxide film breakdown voltage, there is a problem that it takes a long time. That is, it takes about 20 hours even if the time required from the element production to the oxide film withstand voltage measurement is simply added, and it actually takes about one week due to various preparation work. Therefore, the present invention provides a method for evaluating an oxide film breakdown voltage of a silicon wafer, which can easily and quickly evaluate the oxide film breakdown voltage, and therefore the cost required for the evaluation is significantly low. The object is to provide a stable silicon wafer.
【０００４】[0004]
【課題を解決するための手段】本発明者は上記目的を達
成するために研究を重ね、シリコンウェーハにレーザー
を照射したときの散乱光に着目し、この散乱光を生じさ
せるレーザー散乱体の密度が酸化膜耐圧に強い因果関係
を与えており、すなわちレーザー散乱体がシリコンウェ
ーハの表層部に多く存在すると、酸化膜耐圧が劣化する
ことを見出し、こうして本発明を完成するに至った。す
なわち本発明は、シリコンウェーハ表層のレーザー散乱
体密度に基づいて、前記シリコンウェーハの酸化膜耐圧
良品率又は不良品率を評価することを特徴とするシリコ
ンウェーハの酸化膜耐圧の評価方法であり、また、表層
のレーザー散乱体密度が５×１０5／ｃｍ3以下であるこ
とを特徴とするシリコンウェーハである。Means for Solving the Problems The present inventor has conducted extensive research to achieve the above object, paying attention to scattered light when a silicon wafer is irradiated with a laser, and arranging the density of a laser scatterer which causes this scattered light. Has a strong causal relationship with the oxide film withstand voltage, that is, the oxide film withstand voltage is deteriorated when many laser scatterers are present in the surface layer portion of the silicon wafer, and thus the present invention has been completed. That is, the present invention, based on the laser scatterer density of the silicon wafer surface layer, is an evaluation method of the oxide film breakdown voltage of the silicon wafer, characterized by evaluating the oxide film breakdown rate good or defective product rate of the silicon wafer, Further, the surface layer has a laser scatterer density of 5 × 10 5 / cm 3 or less, which is a silicon wafer.
【０００５】[0005]
【実施例】以下に本発明の実施例を説明する。引上げ法
すなわちチョクラルスキー法によって単結晶シリコンイ
ンゴットを製造し、これにスライス・ラップ・面取り・
化学研磨の各工程を施してシリコンウェーハの試料とし
た。試料の諸元は、直径６インチ、結晶軸＜１００＞、
Ｐ型、ボロンドープ、抵抗率１０〜２０Ωｃｍ、酸素濃
度１２〜１５×１０17ａｔｏｍｓ／ｃｍ3である。この
試料に各種の熱処理を施してレーザー散乱体の密度を変
化させ、しかる後ウェーハ表層部のレーザー散乱体の密
度を測定した。図１はレーザー散乱体の測定装置を示し
ている。シリコンウェーハ１の表面に向けてレーザー発
射装置２より波長１．３μｍのレーザー光が垂直に照射
され、シリコンウェーハの表面にこのビームをフォーカ
スして、ウェーハ表面上の任意に定めた複数のポイント
を、ウェーハがスライドすることで走査する。ビームが
欠陥に当たるとわずかな位相のずれを生じるが、このず
れを検出することで欠陥を検出する。EXAMPLES Examples of the present invention will be described below. A single crystal silicon ingot is manufactured by the pulling method, that is, the Czochralski method, and slice, lap, chamfer,
Each step of chemical polishing was performed to obtain a silicon wafer sample. The specifications of the sample are as follows: diameter 6 inches, crystal axis <100>,
P type, boron doped, resistivity 10 to 20 Ωcm, and oxygen concentration 12 to 15 × 10 17 atoms / cm 3 . This sample was subjected to various heat treatments to change the density of the laser scatterers, and then the density of the laser scatterers on the surface layer of the wafer was measured. FIG. 1 shows a measuring device for a laser scatterer. A laser beam having a wavelength of 1.3 μm is vertically emitted from the laser emitting device 2 toward the surface of the silicon wafer 1, and the beam is focused on the surface of the silicon wafer to set a plurality of arbitrarily defined points on the surface of the wafer. , The wafer is scanned by sliding. When the beam hits the defect, a slight phase shift occurs, and the defect is detected by detecting this shift.
【０００６】図２はシリコンウェーハ１の表面近傍（０
〜３μｍ）でのレーザー散乱体の密度と酸化膜耐圧が３
ＭＶ／ｃｍ以上、８ＭＶ／ｃｍ以下のＢモード不良品率
との関係を示す。同図より明らかなように、レーザー散
乱体密度とＢモード不良品率との間には著しい相関関係
があり、すなわちレーザー散乱体密度が増加するとＢモ
ード不良品率が増加することが良く理解される。また図
３はレーザー散乱体の密度と酸化膜耐圧が８ＭＶ／ｃｍ
以上のＣモード良品率との関係を示し、同図より明らか
なように、レーザー散乱体密度が増加するとＣモード良
品率が減少することが理解される。FIG. 2 shows the vicinity of the surface of the silicon wafer 1 (0
Density of the laser scatterer and the oxide film withstand voltage of 3 μm) are 3
The relationship with the B-mode defective product rate of MV / cm or more and 8 MV / cm or less is shown. As is clear from the figure, there is a significant correlation between the density of the laser scatterers and the B-mode defective product rate, that is, it is well understood that the B-mode defective product ratio increases as the laser scatterer density increases. It Further, FIG. 3 shows that the density of the laser scatterer and the breakdown voltage of the oxide film are 8 MV / cm.
The above relationship with the C-mode non-defective rate is shown, and as is clear from the figure, it is understood that the C-mode non-defective rate decreases as the laser scatterer density increases.
【０００７】これらの図２及び図３自体は、図１のレー
ザー散乱体測定装置によってレーザー散乱体密度を測定
し、他方、実際に酸化膜耐圧測定用のＭＯＳキャパシタ
ーを作成して酸化膜耐圧を測定した結果得られる図であ
るが、これらの図をひとたび得ておくことにより、シリ
コンウェーハの酸化膜耐圧を迅速に評価することができ
る。すなわち図１のレーザー散乱体測定装置によるレー
ザー散乱体密度の測定は、たとえば本装置で１ポイント
当たり測定できる領域は、１２８×４５０μｍであるか
ら、ウェーハ面内の代表値とするためには少なくとも３
０ポイント以上は必要となってくるが、それでも要する
時間は１時間程度ですむ。レーザーの走査方向はウェー
ハの深さ方向と、水平方向の２通りがあるが、本実施例
では、表面近傍（深さ０〜３μｍ）の値をとるため走査
を水平方向とし、ウェーハ中の５個所の位置で、それぞ
れ６ポイント、計３０ポイントのレーザー散乱体を測定
し、ウェーハ面内の代表値とした。このようにして、あ
とは例えば図３を用いることにより、そのシリコンウェ
ーハの酸化膜耐圧良品率を直ちに評価することができ、
結局従来の直接的な測定によって酸化膜耐圧を求めてい
たときに比較して、著しく迅速に酸化膜耐圧を評価する
ことができる。また酸化膜耐圧良品率の仕様として例え
ば９５％以上が要求されるときには、図３よりレーザー
散乱体密度としては約５×１０5／ｃｍ3以下である必要
があることが解るから、個々のシリコンウェーハ表層の
レーザー散乱体密度を測定し、この測定値が５×１０5
／ｃｍ3以下であるか否かによって当該シリコンウェー
ハの採否を容易且つ迅速に決定することができる。2 and 3 themselves measure the density of the laser scatterer by the laser scatterer measuring apparatus of FIG. 1, while actually making a MOS capacitor for measuring the oxide film breakdown voltage to measure the oxide film breakdown voltage. Although these figures are obtained as a result of measurement, once these figures are obtained, the breakdown voltage of the oxide film of the silicon wafer can be evaluated quickly. That is, in the measurement of the laser scatterer density by the laser scatterer measurement apparatus of FIG. 1, for example, the area that can be measured per point by this apparatus is 128 × 450 μm, and therefore, at least 3 is required to obtain a representative value within the wafer surface.
You will need more than 0 points, but it still takes about 1 hour. There are two laser scanning directions, the depth direction of the wafer and the horizontal direction. In the present embodiment, since the value in the vicinity of the surface (depth of 0 to 3 μm) is taken, the scanning is performed in the horizontal direction. A total of 30 points of laser scatterers were measured at each position, which was set as a representative value within the wafer surface. Thus, after that, by using, for example, FIG. 3, it is possible to immediately evaluate the oxide film withstand rate of the silicon wafer,
As a result, the oxide film breakdown voltage can be evaluated significantly more rapidly than when the oxide film breakdown voltage is obtained by the conventional direct measurement. Further, when the specification of the yield ratio of the oxide film withstand rate is, for example, 95% or more, it can be seen from FIG. 3 that the laser scatterer density needs to be about 5 × 10 5 / cm 3 or less. The density of the laser scatterer on the surface of the wafer was measured and the measured value was 5 × 10 5.
Whether or not the silicon wafer is adopted can be determined easily and quickly depending on whether or not it is less than or equal to / cm 3 .
【０００８】[0008]
【発明の効果】本発明方法は、シリコンウェーハ表層の
レーザー散乱体密度に基づいてシリコンウェーハの酸化
膜耐圧良品率又は不良品率を評価するものであるから、
個々のシリコンウェーハの酸化膜耐圧を容易且つ迅速に
評価することができる。また本発明は表層のレーザー散
乱体密度が５×１０5／ｃｍ3以下のシリコンウェーハで
あるから、その酸化膜耐圧良品率は約９５％以上と著し
く良好なシリコンウェーハである。The method of the present invention evaluates the yield ratio of defective oxide film or the defective product of the silicon wafer based on the density of the laser scatterers on the surface layer of the silicon wafer.
It is possible to easily and quickly evaluate the withstand voltage of the oxide film of each silicon wafer. Further, since the present invention is a silicon wafer having a surface laser scatterer density of 5 × 10 5 / cm 3 or less, the yield rate of the oxide film withstand voltage is about 95% or more, which is a remarkably good silicon wafer.
【図１】レーザー散乱体密度の測定手法を示す図FIG. 1 is a diagram showing a method for measuring a laser scatterer density.
【図２】レーザー散乱体密度とＢモード不良品率との関
係を示す図FIG. 2 is a diagram showing the relationship between the density of laser scatterers and the B-mode defective product rate.
【図３】同じくＣモード良品率との関係を示す図FIG. 3 is a graph showing a relationship with the C-mode non-defective rate.
１…シリコンウェーハ ２…レーザー発射装置 1 ... Silicon wafer 2 ... Laser emitting device
───────────────────────────────────────────────────── フロントページの続き (72)発明者 河野 光雄 神奈川県平塚市四之宮2612番地 コマツ電 子金属株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Kono 2612 Shinomiya, Hiratsuka City, Kanagawa Prefecture Komatsu Electronic Metals Co., Ltd.
Claims (2)
度に基づいて、前記シリコンウェーハの酸化膜耐圧良品
率又は不良品率を評価することを特徴とするシリコンウ
ェーハの酸化膜耐圧の評価方法。1. A method for evaluating a breakdown voltage of an oxide film of a silicon wafer, which comprises evaluating a non-defective product rate or a defective product rate of the oxide film breakdown voltage of the silicon wafer based on a density of a laser scatterer on a surface layer of the silicon wafer.
ｃｍ3以下であることを特徴とするシリコンウェーハ。2. A laser scatterer density of the surface layer is 5 × 10 5 /
A silicon wafer having a size of 3 cm3 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15796593A JP3210489B2 (en) | 1993-06-02 | 1993-06-02 | Silicon wafer and method for evaluating withstand voltage of oxide film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15796593A JP3210489B2 (en) | 1993-06-02 | 1993-06-02 | Silicon wafer and method for evaluating withstand voltage of oxide film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06349923A true JPH06349923A (en) | 1994-12-22 |
| JP3210489B2 JP3210489B2 (en) | 2001-09-17 |
Family
ID=15661320
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15796593A Expired - Lifetime JP3210489B2 (en) | 1993-06-02 | 1993-06-02 | Silicon wafer and method for evaluating withstand voltage of oxide film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3210489B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744380A (en) * | 1993-08-23 | 1998-04-28 | Komatsu Electronic Metals Co., Ltd. | Method of fabricating an epitaxial wafer |
-
1993
- 1993-06-02 JP JP15796593A patent/JP3210489B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744380A (en) * | 1993-08-23 | 1998-04-28 | Komatsu Electronic Metals Co., Ltd. | Method of fabricating an epitaxial wafer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3210489B2 (en) | 2001-09-17 |
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