JP7729290B2 - Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates - Google Patents
Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substratesInfo
- Publication number
- JP7729290B2 JP7729290B2 JP2022140241A JP2022140241A JP7729290B2 JP 7729290 B2 JP7729290 B2 JP 7729290B2 JP 2022140241 A JP2022140241 A JP 2022140241A JP 2022140241 A JP2022140241 A JP 2022140241A JP 7729290 B2 JP7729290 B2 JP 7729290B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- silicon single
- oxide film
- breakdown voltage
- defect
- 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.)
- Active
Links
Landscapes
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Description
本発明は、シリコン単結晶基板の酸化膜耐圧特性の評価方法及びシリコン単結晶基板の合否判定方法に関する。 The present invention relates to a method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates and a method for determining the pass/fail status of silicon single crystal substrates.
近年、半導体素子の微細化、高集積化に伴い、半導体結晶中の結晶欠陥の制御及び正確な評価がより重要になっている。
シリコン単結晶基板上に形成される半導体素子にはゲート酸化膜等の絶縁膜が用いられるが、シリコン単結晶基板中に欠陥が存在すると、絶縁膜の品質が低下することが広く知られている。そのため、高品質な半導体素子を形成するためには、高品質な絶縁膜が必要になる。
In recent years, with the miniaturization and high integration of semiconductor elements, the control and accurate evaluation of crystal defects in semiconductor crystals has become more important.
Semiconductor devices formed on silicon single crystal substrates use insulating films such as gate oxide films, but it is widely known that the presence of defects in the silicon single crystal substrate reduces the quality of the insulating film. Therefore, high-quality insulating films are necessary to form high-quality semiconductor devices.
絶縁膜の信頼性評価方法の一つに、ＧＯＩ（Ｇａｔｅ Ｏｘｉｄｅ Ｉｎｔｅｇｒｉｔｙ）評価がある。これは、シリコン単結晶基板上に酸化膜を形成し、酸化膜上に電極を形成することで、ＭＯＳ（Ｍｅｔａｌ Ｏｘｉｄｅ Ｓｅｍｉｃｏｎｄｕｃｔｏｒ）構造を形成する。このＭＯＳに、高電界を印加することで酸化膜を破壊し、その破壊電界強度を測定することで酸化膜信頼性を評価する手法である。ＧＯＩ評価は、結晶欠陥（ＣＯＰ（Ｃｒｙｓｔａｌ Ｏｒｉｇｉｎａｔｅｄ Ｐａｒｔｉｃｌｅ）や酸素析出物等）や、加工起因欠陥（スクラッチ等）を高精度に検出、評価することができるという特徴がある。
しかしながら、ＧＯＩ評価を行うためには、ＭＯＳ構造を作製する必要があるため、複雑且つ長時間のＭＯＳ形成工程を経なければならず、時間とコストが掛かるという欠点があった。
One method for evaluating the reliability of insulating films is GOI (Gate Oxide Integrity) evaluation. This involves forming an oxide film on a silicon single crystal substrate and forming electrodes on the oxide film to form a MOS (Metal Oxide Semiconductor) structure. A high electric field is applied to this MOS to destroy the oxide film, and the breakdown field strength is measured to evaluate the oxide film reliability. GOI evaluation is characterized by its ability to detect and evaluate crystal defects (such as COPs (Crystal Originated Particles) and oxygen precipitates) and processing-induced defects (such as scratches) with high accuracy.
However, in order to perform GOI evaluation, it is necessary to fabricate a MOS structure, which requires a complicated and lengthy MOS formation process, resulting in the drawback of being time-consuming and costly.
特許文献１には、異物検査装置と走査型電子顕微鏡を使用して、酸化膜耐圧不良率を推定する方法が開示されている。特許文献２には、異方性エッチングを行い、結晶欠陥に起因したエッチング残渣を露出させることで基板内部の結晶欠陥を評価する方法が開示されている。また、特許文献３には、アンモニア－過酸化水素水からなるエッチング液にシリコンウェーハを長時間浸漬させることで、加工起因の欠陥または金属汚染起因欠陥を区別する方法が開示されている。 Patent Document 1 discloses a method for estimating the oxide film breakdown voltage failure rate using a foreign matter inspection device and a scanning electron microscope. Patent Document 2 discloses a method for evaluating crystal defects inside a substrate by performing anisotropic etching and exposing etching residue caused by crystal defects. Furthermore, Patent Document 3 discloses a method for distinguishing between defects caused by processing and defects caused by metal contamination by immersing a silicon wafer for a long period of time in an etching solution consisting of ammonia and hydrogen peroxide solution.
しかし、特許文献１では、酸素析出物をパーティクルと区別する方法が開示されておらず、結晶欠陥である酸素析出物によるＧＯＩ不良と、加工工程で付着するパーティクルによるＧＯＩ不良が区別できないため、ＧＯＩ不良の原因の推定精度が十分ではない。特許文献２、３では、シリコン単結晶基板がエッチングされてしまうため、エッチング前にシリコン単結晶基板に存在した欠陥が酸素析出物であるかどうかを判断することができない。 However, Patent Document 1 does not disclose a method for distinguishing oxygen precipitates from particles, and it is not possible to distinguish between GOI defects caused by oxygen precipitates, which are crystal defects, and GOI defects caused by particles that adhere during the processing process, resulting in insufficient accuracy in estimating the cause of GOI defects. In Patent Documents 2 and 3, because the silicon single crystal substrate is etched, it is not possible to determine whether defects present in the silicon single crystal substrate before etching are oxygen precipitates.
本発明は、上記問題を解決するためになされたものであり、簡便に、高精度に酸化膜耐圧特性を評価できるシリコン単結晶基板の酸化膜耐圧特性の評価方法、及び、簡便に、高精度にシリコン単結晶基板の合否を判定することができるシリコン単結晶基板の合否判定方法を提供することを目的とする。詳しくは、本発明は、シリコン単結晶基板の表面の結晶欠陥、特に酸素析出物と加工起因のパーティクルとを区別し、簡便に且つ高精度にシリコン単結晶基板表面に形成した際の酸化膜の信頼性を評価することで、シリコン単結晶基板の合否を判定する方法を提供することを目的とする。 The present invention has been made to solve the above problems, and aims to provide a method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates, which can easily and accurately evaluate the oxide film breakdown voltage characteristics, and a method for determining the pass/fail of silicon single crystal substrates, which can easily and accurately determine the pass/fail of silicon single crystal substrates. More specifically, the present invention aims to provide a method for determining the pass/fail of silicon single crystal substrates by distinguishing between crystal defects on the surface of silicon single crystal substrates, particularly oxygen precipitates, and particles caused by processing, and by easily and accurately evaluating the reliability of the oxide film when formed on the surface of a silicon single crystal substrate.
本発明は、上記目的を達成するためになされたものであり、シリコン単結晶基板の酸化膜耐圧特性の評価方法であって、シリコン単結晶基板における欠陥を表面欠陥検査装置で検出し、欠陥座標を取得する第１工程と、前記欠陥座標を基に走査型電子顕微鏡で前記シリコン単結晶基板の欠陥を観察し、欠陥像を取得し、欠陥種を分類する第２工程と、前記シリコン単結晶基板をフッ酸で洗浄する第３工程と、前記フッ酸洗浄後に、前記第１工程で取得した前記欠陥座標を基に、走査型電子顕微鏡で欠陥を観察し、欠陥像を取得し、欠陥種を分類する第４工程と、前記第２工程及び前記第４工程で取得した欠陥像及び欠陥種を比較して酸素析出物を抽出する第５工程と、前記第１乃至第５工程から酸化膜耐圧劣化の原因となる欠陥を抽出し、前記酸化膜耐圧劣化欠陥の座標を基に擬似的な酸化膜耐圧劣化マップを作成する第６工程と、を有することを特徴とするシリコン単結晶基板の酸化膜耐圧特性の評価方法を提供する。 The present invention has been made to achieve the above-mentioned object, and provides a method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate, comprising: a first step of detecting defects in the silicon single crystal substrate using a surface defect inspection device and obtaining defect coordinates; a second step of observing the defects in the silicon single crystal substrate using a scanning electron microscope based on the defect coordinates, obtaining defect images, and classifying the defect types; a third step of cleaning the silicon single crystal substrate with hydrofluoric acid; a fourth step of observing the defects using a scanning electron microscope after the hydrofluoric acid cleaning, obtaining defect images, and classifying the defect types based on the defect coordinates obtained in step one; a fifth step of comparing the defect images and defect types obtained in steps two and four to extract oxygen precipitates; and a sixth step of extracting defects that cause oxide film breakdown voltage degradation from steps one through five and creating a pseudo oxide film breakdown voltage degradation map based on the coordinates of the oxide film breakdown voltage degradation defects.
このようなシリコン単結晶基板の酸化膜耐圧特性の評価方法によれば、酸素析出物を簡便に、高精度に抽出することができ、簡便に、高精度に酸化膜耐圧特性を評価できる。 This method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates allows for easy and highly accurate extraction of oxygen precipitates, enabling easy and highly accurate evaluation of the oxide film breakdown voltage characteristics.
このとき、前記第２、第４工程で分類する前記欠陥種を、パーティクル、ピット、スクラッチ、ＰＩＤ（Ｐｏｌｉｓｈｅｄ Ｉｎｄｕｃｅｄ Ｄｅｆｅｃｔ）とすることができる。 In this case, the defect types classified in the second and fourth steps can be particles, pits, scratches, and PIDs (Polished Induced Defects).
これにより、第５工程において、酸素析出物を抽出することができる。
なお、前記第２工程の欠陥分類は、走査型電子顕微鏡像を目視で確認して分類しても良いし、ＲＢＢ（Ｒｕｌｅ－Ｂａｓｅｄ Ｂｉｎｎｉｎｇ）による自動分類でも良い。より好ましくは、ＣＮＮ（Ｃｏｎｖｏｌｕｔｉｏｎａｌ Ｎｅｕｒａｌ Ｎｅｔｗｏｒｋ）を利用し、高精度且つ高スループットに自動分類することができる。
This allows oxygen precipitates to be extracted in the fifth step.
The defect classification in the second step may be performed by visually checking a scanning electron microscope image or by automatic classification using Rule-Based Binning (RBB).More preferably, automatic classification can be performed with high accuracy and high throughput by using a Convolutional Neural Network (CNN).
このとき、前記酸素析出物を抽出する第５工程において、前記第２工程でパーティクルに分類され、前記第４工程でピットに分類された欠陥を酸素析出物に再分類するとともに、前記第２工程でピットに分類され、前記第４工程でピットとして分類された欠陥のうち、前記第４工程のピットの深さが前記第２工程よりも深い欠陥又は前記第４工程のピットの内径が前記第２工程よりも大きい欠陥を酸素析出物に再分類することができる。 In this case, in the fifth step of extracting the oxygen precipitates, defects classified as particles in the second step and as pits in the fourth step are reclassified as oxygen precipitates, and among the defects classified as pits in the second step and as pits in the fourth step, defects whose pit depth in the fourth step is deeper than in the second step or whose inner diameter in the fourth step is larger than in the second step can be reclassified as oxygen precipitates.
これにより、酸素析出物を再分類することができる。
酸素析出物はフッ酸により選択的にエッチングされてピット化するため、前記第５工程では、前記第２工程でパーティクルに分類され、前記第４工程（フッ酸洗浄後）でピットに分類された欠陥を酸素析出物に再分類することで、パーティクルと酸素析出物を区別できる。また、酸素析出物の一部はシリコン単結晶基板製造工程中にエッチングされることでピット化しているが、ピットの底にはエッチングされなかった酸素析出物が残留している場合がある。そのため、前記第２工程でピットに分類され、前記第４工程でピットとして分類された欠陥のうち、フッ酸洗浄後のピットの深さが洗浄前よりも深い欠陥又はフッ酸洗浄後のピットの内径が洗浄前よりも大きい欠陥を酸素析出物に再分類することができる。
This allows the oxygen precipitates to be reclassified.
Since oxygen precipitates are selectively etched by hydrofluoric acid to form pits, in the fifth step, defects classified as particles in the second step and as pits in the fourth step (after hydrofluoric acid cleaning) are reclassified as oxygen precipitates, thereby making it possible to distinguish between particles and oxygen precipitates. Furthermore, although some oxygen precipitates are etched to form pits during the silicon single crystal substrate manufacturing process, some unetched oxygen precipitates may remain at the bottom of the pits. Therefore, among the defects classified as pits in the second step and as pits in the fourth step, defects whose pit depth after hydrofluoric acid cleaning is deeper than before cleaning or whose inner diameter after hydrofluoric acid cleaning is larger than before cleaning can be reclassified as oxygen precipitates.
このとき、前記酸化膜耐圧劣化の原因となる欠陥を、ピット、酸素析出物、スクラッチとすることができる。 In this case, the defects that cause the deterioration of the oxide film's breakdown voltage can be pits, oxygen precipitates, or scratches.
これにより、前記酸化膜耐圧劣化の原因となる欠陥の座標を基に、擬似的な酸化膜耐圧劣化マップを作成することで、高精度な酸化膜耐圧特性を評価することができる。前記酸化膜耐圧劣化マップの様式は特に限定されないが、好ましくはＧＯＩ評価で得られる酸化膜耐圧劣化マップを模したマップとすることができる。 This allows for highly accurate evaluation of oxide breakdown voltage characteristics by creating a pseudo oxide breakdown voltage degradation map based on the coordinates of the defects that cause the oxide breakdown voltage degradation. The format of the oxide breakdown voltage degradation map is not particularly limited, but it is preferably a map that mimics the oxide breakdown voltage degradation map obtained by GOI evaluation.
本発明は、上記目的を達成するためになされたものであり、先に記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法を用いたシリコン単結晶基板の合否判定方法であって、前記第６工程で作成した前記擬似的な酸化膜耐圧劣化マップから、酸化膜耐圧不良率を算出し、予め設定した所定の酸化膜耐圧不良率を超えた場合に、前記シリコン単結晶基板を不合格と判定することを特徴とするシリコン単結晶基板の合否判定方法を提供する。 The present invention has been made to achieve the above-mentioned object, and provides a method for determining the acceptability of silicon single crystal substrates using the previously described method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates, characterized in that the oxide film breakdown voltage defect rate is calculated from the pseudo oxide film breakdown voltage degradation map created in step 6, and the silicon single crystal substrate is determined to be unacceptable if the oxide film breakdown voltage defect rate exceeds a predetermined predetermined value.
このようなシリコン単結晶基板の合否判定方法によれば、高精度且つ高スループットに酸化膜耐圧特性を評価することができ、酸化膜耐圧不良があるシリコン基板の出荷を高精度に防ぐことができる。 This method for determining the pass/fail status of silicon single crystal substrates makes it possible to evaluate the oxide film breakdown voltage characteristics with high accuracy and high throughput, and can accurately prevent the shipment of silicon substrates with poor oxide film breakdown voltage characteristics.
以上のように、本発明のシリコン単結晶基板の酸化膜耐圧特性の評価方法によれば、酸素析出物を簡便に、高精度に抽出することができ、簡便に、高精度に酸化膜耐圧特性を評価することが可能となる。
本発明のシリコン単結晶基板の合否判定方法によれば、簡便に、高精度にシリコン単結晶基板の合否を判定することが可能となる。高精度且つ高スループットに酸化膜耐圧特性を評価することができ、酸化膜耐圧不良があるシリコン基板の出荷を高精度に防ぐことが可能となる。
本発明のシリコン単結晶基板の酸化膜耐圧特性の評価方法及びシリコン単結晶基板の合否判定方法を用いれば、高精度且つ高スループットに酸化膜耐圧特性を評価し、シリコン単結晶基板の合否を判定することができ、酸化膜耐圧不良があるシリコン単結晶基板の出荷を高精度に防ぐことが可能になる。
As described above, according to the method for evaluating the dielectric strength characteristics of an oxide film of a silicon single crystal substrate of the present invention, oxygen precipitates can be extracted easily and with high accuracy, and the dielectric strength characteristics of an oxide film can be evaluated easily and with high accuracy.
According to the method for determining the acceptability of a silicon single crystal substrate of the present invention, it is possible to easily and highly accurately determine the acceptability of a silicon single crystal substrate. The oxide film breakdown voltage characteristics can be evaluated with high accuracy and high throughput, and it is possible to accurately prevent the shipment of silicon substrates with poor oxide film breakdown voltage characteristics.
By using the method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate and the method for determining the acceptability of a silicon single crystal substrate of the present invention, it is possible to evaluate the oxide film breakdown voltage characteristics with high precision and high throughput, determine the acceptability of a silicon single crystal substrate, and prevent the shipment of silicon single crystal substrates with poor oxide film breakdown voltage characteristics with high precision.
以下、本発明を詳細に説明するが、本発明はこれらに限定されるものではない。 The present invention is described in detail below, but is not limited to these.
上述のように、簡便に、高精度に酸化膜耐圧特性を評価できるシリコン単結晶基板の酸化膜耐圧特性の評価方法、及び、簡便に、高精度にシリコン単結晶基板の合否を判定することができるシリコン単結晶基板の合否判定方法が求められていた。 As described above, there has been a need for a method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates that can easily and accurately evaluate the oxide film breakdown voltage characteristics, as well as a method for determining the pass/fail of silicon single crystal substrates that can easily and accurately determine the pass/fail of silicon single crystal substrates.
本発明者は、上記課題について鋭意検討を重ねた結果、シリコン単結晶基板の酸化膜耐圧特性の評価方法であって、シリコン単結晶基板における欠陥を表面欠陥検査装置で検出し、欠陥座標を取得する第１工程と、前記欠陥座標を基に走査型電子顕微鏡で前記シリコン単結晶基板の欠陥を観察し、欠陥像を取得し、欠陥種を分類する第２工程と、前記シリコン単結晶基板をフッ酸で洗浄する第３工程と、前記フッ酸洗浄後に、前記第１工程で取得した前記欠陥座標を基に、走査型電子顕微鏡で欠陥を観察し、欠陥像を取得し、欠陥種を分類する第４工程と、前記第２工程及び前記第４工程で取得した欠陥像及び欠陥種を比較して酸素析出物を抽出する第５工程と、前記第１乃至第５工程から酸化膜耐圧劣化の原因となる欠陥を抽出し、前記酸化膜耐圧劣化欠陥の座標を基に擬似的な酸化膜耐圧劣化マップを作成する第６工程と、を有することを特徴とするシリコン単結晶基板の酸化膜耐圧特性の評価方法により、酸素析出物を簡便に、高精度に抽出することができ、簡便に、高精度に酸化膜耐圧特性を評価できること、及び、
先に記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法を用いたシリコン単結晶基板の合否判定方法であって、前記第６工程で作成した前記擬似的な酸化膜耐圧劣化マップから、酸化膜耐圧不良率を算出し、予め設定した所定の酸化膜耐圧不良率を超えた場合に、前記シリコン単結晶基板を不合格と判定することを特徴とするシリコン単結晶基板の合否判定方法により、簡便に、高精度にシリコン単結晶基板の合否を判定することができることを見出し、本発明を完成した。
As a result of extensive research into the above-mentioned problems, the present inventors have discovered a method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate, comprising: a first step of detecting defects in a silicon single crystal substrate with a surface defect inspection device and acquiring defect coordinates; a second step of observing the defects in the silicon single crystal substrate with a scanning electron microscope based on the defect coordinates, acquiring defect images, and classifying the defect types; a third step of cleaning the silicon single crystal substrate with hydrofluoric acid; and a third step of observing the defects with a scanning electron microscope based on the defect coordinates acquired in the first step after the hydrofluoric acid cleaning, a fourth step of acquiring an image of the oxide film and classifying the defect types; a fifth step of comparing the defect images and defect types acquired in the second step and the fourth step to extract oxygen precipitates; and a sixth step of extracting defects that cause oxide film breakdown voltage degradation from the first to fifth steps and creating a pseudo oxide film breakdown voltage degradation map based on the coordinates of the oxide film breakdown voltage degradation defects, thereby enabling the oxide film breakdown voltage characteristics to be easily extracted with high accuracy, and enabling the oxide film breakdown voltage characteristics to be easily evaluated with high accuracy;
The inventors have found that the pass/fail of a silicon single crystal substrate can be determined simply and with high accuracy by using the above-described method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate, the method being characterized in that an oxide film breakdown voltage defect rate is calculated from the pseudo oxide film breakdown voltage degradation map created in the sixth step, and the silicon single crystal substrate is determined to be unacceptable when the oxide film breakdown voltage defect rate exceeds a predetermined predetermined value, and have completed the present invention.
以下、本発明に係るシリコン単結晶基板の酸化膜耐圧特性の評価方法及びシリコン単結晶基板の合否判定方法について図１を参照しながら説明する。 The method for evaluating the oxide film breakdown voltage characteristics of silicon single crystal substrates and the method for determining the pass/fail of silicon single crystal substrates according to the present invention will be described below with reference to Figure 1.
（本発明に係るシリコン単結晶基板の酸化膜耐圧特性の評価方法及びシリコン単結晶基板の合否判定方法）
図１は、本発明に係るシリコン単結晶基板の酸化膜耐圧特性の評価方法及び本発明に係るシリコン単結晶基板の合否判定方法の一例を示すフローチャートである。
図１に示す第１工程～第７工程は、本発明に係るシリコン単結晶基板の合否判定方法の一例である。このうち、第１工程～第６工程は、本発明に係るシリコン単結晶基板の酸化膜耐圧特性の評価方法の一例である。そのため、本発明に係るシリコン単結晶基板の合否判定方法は、本発明に係るシリコン単結晶基板の酸化膜耐圧特性の評価方法を用いたシリコン単結晶基板の合否判定方法であるといえる。
(Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates according to the present invention)
FIG. 1 is a flowchart showing an example of a method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to the present invention and a method for determining the acceptability of a silicon single crystal substrate according to the present invention.
1 are an example of a method for determining the pass/fail of a silicon single crystal substrate according to the present invention. Among these, steps 1 to 6 are an example of a method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to the present invention. Therefore, the method for determining the pass/fail of a silicon single crystal substrate according to the present invention can be said to be a method for determining the pass/fail of a silicon single crystal substrate using the method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to the present invention.
（第１工程）
第１工程は、シリコン単結晶基板における欠陥を表面欠陥検査装置で検出し、欠陥座標を取得する工程である。
まず、評価するシリコン単結晶基板を準備する。評価するシリコン単結晶基板は、チョクラルスキー法で製造されても良いし、フローティングゾーン法で製造されても良い。また、結晶方位は特に限定されない。
表面欠陥検査装置で、このシリコン単結晶基板の欠陥を検出し、欠陥座標を取得する。表面欠陥検査装置は、パーティクルカウンターとすることができ、例えば、ＫＬＡ製Ｓｕｒｆｓｃａｎ ＳＰ５を用い、Ｏｂｌｉｑｕｅモードの１９ｎｍＵｐで測定することができる。
(1st step)
The first step is a step of detecting defects in a silicon single crystal substrate using a surface defect inspection device and acquiring defect coordinates.
First, a silicon single crystal substrate to be evaluated is prepared. The silicon single crystal substrate to be evaluated may be manufactured by the Czochralski method or the floating zone method. Furthermore, there are no particular restrictions on the crystal orientation.
Defects in this silicon single crystal substrate are detected and defect coordinates are obtained using a surface defect inspection device. The surface defect inspection device can be a particle counter, for example, a KLA Surfscan SP5, which can be used to measure up to 19 nm in Oblique mode.
（第２工程）
第２工程は、第１工程で取得した欠陥座標を基に走査型電子顕微鏡で欠陥を観察し、欠陥の走査型電子顕微鏡像（欠陥像）を取得し、欠陥種を分類する工程である。
走査型電子顕微鏡像を基に欠陥種を分類するため、欠陥形状や高さ情報に基づいて分類することが好ましく、パーティクル（凸欠陥）、ピット（凹欠陥）、スクラッチ（線状に伸びる凹欠陥）、ＰＩＤ（Ｐｏｌｉｓｈｅｄ Ｉｎｄｕｃｅｄ Ｄｅｆｅｃｔ、幅が広く高さの低い欠陥）に分類することができる。
このとき、パーティクルとピットは酸素析出物に分類される可能性がある欠陥種であるので、分類した欠陥種から酸素析出物として識別する場合にはパーティクルとピットを欠陥種の分類対象に含める必要がある。
(Second process)
The second step is a step of observing the defect with a scanning electron microscope based on the defect coordinates obtained in the first step, obtaining a scanning electron microscope image of the defect (defect image), and classifying the defect type.
Since defect types are classified based on scanning electron microscope images, it is preferable to classify based on defect shape and height information, and defects can be classified into particles (convex defects), pits (concave defects), scratches (linearly extending concave defects), and PIDs (Polished Induced Defects, which are wide and short defects).
In this case, since particles and pits are defect types that may be classified as oxygen precipitates, when identifying classified defect types as oxygen precipitates, particles and pits must be included in the classification of defect types.
（第３工程）
第３工程は、シリコン単結晶基板をフッ酸で洗浄する工程である。
この工程では、シリコン単結晶基板表面に存在する酸素析出物をエッチングしてピット化するために、シリコン単結晶基板をフッ酸で洗浄する。
フッ酸の濃度及び洗浄時間は特に限定されない。シリコン単結晶基板上に存在する酸素析出物が十分にエッチングされるフッ酸濃度、及び洗浄時間であれば良いが、安全、操業上の観点から、フッ酸は５０ｗｔ％以下、洗浄時間は１０分以内であることが好ましく、フッ酸の質量パーセント濃度を０．５～１０ｗｔ％、洗浄時間を１～５分とすることがより好ましい。また、新たに搬送中の発塵等によるパーティクル付着を防ぐために、フッ酸洗浄後に、過酸化水素水やオゾン水などで薄い酸化膜を形成しても良い。
(Third step)
The third step is a step of cleaning the silicon single crystal substrate with hydrofluoric acid.
In this step, the silicon single crystal substrate is cleaned with hydrofluoric acid in order to etch away oxygen precipitates present on the surface of the silicon single crystal substrate and turn them into pits.
The concentration of hydrofluoric acid and the cleaning time are not particularly limited. The hydrofluoric acid concentration and cleaning time may be selected so long as they sufficiently etch away oxygen precipitates present on the silicon single crystal substrate. However, from the viewpoint of safety and operation, the hydrofluoric acid concentration is preferably 50 wt % or less and the cleaning time is 10 minutes or less, and it is more preferable that the mass percent concentration of hydrofluoric acid is 0.5 to 10 wt %, and the cleaning time is 1 to 5 minutes. Furthermore, in order to prevent particle adhesion due to dust generation during transportation, after the hydrofluoric acid cleaning, a thin oxide film may be formed using hydrogen peroxide water, ozone water, or the like.
（第４工程）
第４工程は、前記フッ酸洗浄後に、第１工程で取得した欠陥座標を基に走査型電子顕微鏡で欠陥を観察し、欠陥の走査型電子顕微鏡像（欠陥像）を取得し、第２工程と同じ判断基準により欠陥種を分類する工程である。
(4th step)
The fourth step is a step in which, after the hydrofluoric acid cleaning, the defects are observed using a scanning electron microscope based on the defect coordinates obtained in the first step, a scanning electron microscope image of the defect (defect image) is obtained, and the defect type is classified using the same criteria as in the second step.
（第５工程）
第５工程は、第２工程と第４工程で得られた欠陥像及び欠陥種を比較して、酸素析出物を抽出する工程である。
酸素析出物はフッ酸により選択的にエッチングされてピット化するため、第２工程でパーティクルに分類され、第４工程のフッ酸洗浄後にピットに分類された欠陥を酸素析出物に再分類することで、パーティクルと酸素析出物を区別できる。
また、シリコン単結晶基板上に存在する酸素析出物の一部は、シリコン単結晶基板製造工程中にエッチングされることでピット化しているが、ピットの底にはエッチングされなかった酸素析出物が残留している場合がある。この残留している酸素析出物をフッ酸で選択的にエッチングすることで、フッ酸洗浄後にピットの深さが深くなったり、ピットの内径が大きくなる。そのため、前記第２工程でピットに分類され、前記第４工程でピットとして分類された欠陥のうち、フッ酸洗浄後のピットの深さが洗浄前よりも深い欠陥及びフッ酸洗浄後のピットの内径が洗浄前よりも大きい欠陥を酸素析出物に再分類する。
酸素析出物以外の欠陥は、フッ酸によってエッチングされないため、フッ酸洗浄前後で得られる欠陥像に特異な変化が無い。そのため、酸素析出物を再分類することで酸素析出物を抽出することができる。酸素析出物を抽出することで、加工工程で付着したパーティクルと酸素析出物、及びＣＯＰや加工起因のピットと酸素析出物起因のピットを分離することができ、ＧＯＩ不良原因の推定精度及び酸化膜耐圧評価精度を向上させることができる。
(5th step)
The fifth step is a step of extracting oxygen precipitates by comparing the defect images and defect types obtained in the second and fourth steps.
Since oxygen precipitates are selectively etched by hydrofluoric acid to form pits, they are classified as particles in the second step, and the defects classified as pits after the hydrofluoric acid cleaning in the fourth step are reclassified as oxygen precipitates, thereby making it possible to distinguish between particles and oxygen precipitates.
Furthermore, although some of the oxygen precipitates present on the silicon single crystal substrate are etched to form pits during the silicon single crystal substrate manufacturing process, there are cases where unetched oxygen precipitates remain at the bottom of the pits. Selective etching of these remaining oxygen precipitates with hydrofluoric acid deepens the depth of the pits or increases the inner diameter of the pits after hydrofluoric acid cleaning. Therefore, among the defects classified as pits in the second step and those classified as pits in the fourth step, defects whose pit depth after hydrofluoric acid cleaning is deeper than before cleaning and defects whose pit inner diameter after hydrofluoric acid cleaning is larger than before cleaning are reclassified as oxygen precipitates.
Defects other than oxygen precipitates are not etched by hydrofluoric acid, so there is no distinctive change in the defect images obtained before and after hydrofluoric acid cleaning. Therefore, oxygen precipitates can be extracted by reclassifying them. Extracting oxygen precipitates makes it possible to separate particles attached during the processing process from oxygen precipitates, as well as pits caused by COPs or processing from pits caused by oxygen precipitates, improving the accuracy of estimating the cause of GOI defects and evaluating the oxide film breakdown voltage.
（第６工程）
第６工程は、第１乃至第５工程から、酸化膜耐圧劣化の原因となる欠陥を抽出し、前記酸化膜耐圧劣化欠陥の座標を基に擬似的な酸化膜耐圧劣化マップを作成する工程である。
このとき、予めシリコン単結晶基板上に存在する欠陥が酸化膜耐圧に与える影響を調査したところ、ピット、酸素析出物、スクラッチが酸化膜耐圧に大きく影響することが判明したため、酸化膜耐圧劣化の原因となる欠陥は、ピット、酸素析出物、スクラッチとすることができる。
前記酸化膜耐圧劣化マップの様式は特に限定されないが、好ましくはＧＯＩ評価で得られる酸化膜耐圧劣化マップを模したマップとすることができる。
このとき、酸素析出物の影響がより強く反映されるＧＯＩの不良モードを評価したい場合は、酸素析出物のみを抽出して評価することで、より一層精度の高い酸化膜耐圧特性の評価が可能となる。
(6th step)
The sixth step is a step of extracting defects that cause degradation of the oxide film breakdown voltage from the first to fifth steps, and creating a pseudo oxide film breakdown voltage degradation map based on the coordinates of the defects that cause degradation of the oxide film breakdown voltage.
At this time, a preliminary investigation into the influence of defects present on the silicon single crystal substrate on the oxide film breakdown voltage revealed that pits, oxygen precipitates, and scratches have a significant effect on the oxide film breakdown voltage. Therefore, the defects that cause deterioration in the oxide film breakdown voltage can be determined to be pits, oxygen precipitates, and scratches.
The format of the oxide breakdown voltage degradation map is not particularly limited, but it is preferable that the map be a map that imitates the oxide breakdown voltage degradation map obtained by GOI evaluation.
In this case, if it is desired to evaluate the failure mode of GOI, which is more strongly influenced by oxygen precipitates, it is possible to evaluate the oxide film breakdown voltage characteristics with even higher accuracy by extracting and evaluating only the oxygen precipitates.
（第７工程）
第７工程は、第６工程で作成した擬似的な酸化膜耐圧劣化マップから、酸化膜耐圧不良率を算出し、予め設定した所定の酸化膜耐圧不良率を超えた場合に、前記シリコン単結晶基板を不合格と判定する工程である。
(7th step)
The seventh step is a step of calculating the oxide film breakdown voltage defect rate from the pseudo oxide film breakdown voltage degradation map created in the sixth step, and judging the silicon single crystal substrate as a reject when the oxide film breakdown voltage defect rate exceeds a predetermined predetermined value.
以下、実施例を挙げて本発明について具体的に説明するが、これは本発明を限定するものではない。 The present invention will be explained in more detail below using examples, but these examples are not intended to limit the scope of the present invention.
（実施例１）
まず、評価するサンプルとして、チョクラルスキー法を用いてシリコン単結晶基板全面が無欠陥となるような条件で製造された直径３００ｍｍのシリコン単結晶基板を２枚用意した。
２枚のうち、１枚については、表面欠陥検査装置（ＳＰ５、Ｏｂｌｉｑｕｅモード、１９ｎｍＵｐ）でシリコン単結晶基板表面に存在する欠陥を検出した。
次に、走査型電子顕微鏡で欠陥を観察し、欠陥種を分類した。
次に、質量パーセント濃度０．５ｗｔ％のフッ酸で３分間洗浄した。
次に、走査型電子顕微鏡で、欠陥の同点観察を行い、欠陥種を分類した。
次に、フッ酸洗浄前後の欠陥像及び欠陥種の分類結果を比較し、フッ酸洗浄前にパーティクルに分類され、フッ酸洗浄後にピットに分類された欠陥を酸素析出物に再分類した。 また、フッ酸洗浄前にピットに分類され、フッ酸洗浄後にピットとして分類された欠陥について、フッ酸洗浄前よりフッ酸洗浄後の内径が大となる欠陥を酸素析出物に再分類した。
次に、酸化膜耐圧劣化欠陥（ピット、酸素析出物、スクラッチ）を抽出し、擬似的な酸化膜耐圧劣化マップ（図２Ｂ）を作成した。
このときのＧＯＩ不良率が２％未満であれば、特に問題はないので、合否判定基準は２％に設定した。
ＧＯＩ不良率を算出したところ０．１％となり、不良率が２％未満であるため、合格と判定した。
もう１枚については、実際のＧＯＩ測定を行い、得られた酸化膜耐圧劣化マップ（図２Ａ）からＧＯＩ不良率を算出したところ、０．２％と求まった。
これから、本発明の評価結果と実際のＧＯＩ測定結果はほぼ同じ結果となり、本発明の評価結果に基づいたシリコン単結晶基板の合否判定は正しいことが証明された。
Example 1
First, two silicon single crystal substrates with a diameter of 300 mm, which were manufactured using the Czochralski method under conditions such that the entire surface of the silicon single crystal substrate was defect-free, were prepared as samples to be evaluated.
For one of the two substrates, defects present on the surface of the silicon single crystal substrate were detected using a surface defect inspection device (SP5, Oblique mode, 19 nm Up).
Next, the defects were observed using a scanning electron microscope and the defect types were classified.
Next, the substrate was washed with hydrofluoric acid having a mass percent concentration of 0.5 wt % for 3 minutes.
Next, the defects were observed at the same point using a scanning electron microscope, and the defect types were classified.
Next, the defect images and the defect classification results before and after the hydrofluoric acid cleaning were compared, and defects that were classified as particles before the hydrofluoric acid cleaning and as pits after the hydrofluoric acid cleaning were reclassified as oxygen precipitates. Also, for defects that were classified as pits before the hydrofluoric acid cleaning and as pits after the hydrofluoric acid cleaning, defects whose inner diameter after the hydrofluoric acid cleaning was larger than before the hydrofluoric acid cleaning were reclassified as oxygen precipitates.
Next, defects (pits, oxygen precipitates, scratches) that deteriorate the dielectric strength of the oxide film were extracted, and a pseudo-dielectric strength deterioration map (FIG. 2B) was created.
If the GOI defect rate is less than 2%, there is no particular problem, so the pass/fail criterion was set at 2%.
The GOI defect rate was calculated to be 0.1%, which was less than 2% and therefore was judged to be acceptable.
For the other wafer, actual GOI measurements were performed, and the GOI defect rate was calculated from the obtained oxide film breakdown voltage degradation map (FIG. 2A), resulting in a value of 0.2%.
From this, the evaluation results of the present invention and the actual GOI measurement results were almost the same, proving that the pass/fail judgment of silicon single crystal substrates based on the evaluation results of the present invention is correct.
（実施例２）
まず、評価するサンプルとして、チョクラルスキー法を用いてシリコン単結晶基板全面が無欠陥となるような条件で製造された直径３００ｍｍのシリコン単結晶基板を２枚用意した。
２枚のうち、１枚については、表面欠陥検査装置（ＳＰ５、Ｏｂｌｉｑｕｅモード、１９ｎｍＵｐ）でシリコン単結晶基板表面に存在する欠陥を検出した。
次に、走査型電子顕微鏡で欠陥を観察し、欠陥種を分類した。
次に、質量パーセント濃度０．５ｗｔ％のフッ酸で３分間洗浄した。
次に、走査型電子顕微鏡で、欠陥の同点観察を行い、欠陥種を分類した。
次に、フッ酸洗浄前後の欠陥像及び欠陥種の分類結果を比較した。
なお、図４は、欠陥例１～３を示す表である。
欠陥例１は、フッ酸洗浄前にパーティクルに分類され、フッ酸洗浄後にピットに分類された欠陥であり、これを酸素析出物に再分類した。
欠陥例２は、フッ酸洗浄前にピットに分類され、フッ酸洗浄後にピットとして分類された欠陥であって、フッ酸洗浄後のピットの内径が洗浄前よりも大きい欠陥であり、これも酸素析出物に再分類した。
欠陥例３は、フッ酸洗浄前にパーティクルに分類され、フッ酸洗浄後にパーティクルとして分類された欠陥であり、これはパーティクルと判定した。
次に、酸化膜耐圧劣化欠陥（ピット、酸素析出物、スクラッチ）を抽出し、擬似的な酸化膜耐圧劣化マップ（図３Ｂ）を作成し、ＧＯＩ不良率を算出したところ３．３％となった。また、不良率が２％以上であるため、不合格と判定した。
もう１枚については、実際にＧＯＩ測定を行い、得られた酸化膜耐圧劣化マップ（図３Ａ）からＧＯＩ不良率を算出したところ、３．５％と求まった。
これから、本発明の評価結果と実際のＧＯＩ測定結果はほぼ同じ結果となり、本発明の評価結果に基づいたシリコン単結晶基板の合否判定は正しいことが証明された。
Example 2
First, two silicon single crystal substrates with a diameter of 300 mm, which were manufactured using the Czochralski method under conditions such that the entire surface of the silicon single crystal substrate was defect-free, were prepared as samples to be evaluated.
For one of the two substrates, defects present on the surface of the silicon single crystal substrate were detected using a surface defect inspection device (SP5, Oblique mode, 19 nm Up).
Next, the defects were observed using a scanning electron microscope and the defect types were classified.
Next, the substrate was washed with hydrofluoric acid having a mass percent concentration of 0.5 wt % for 3 minutes.
Next, the defects were observed at the same point using a scanning electron microscope, and the defect types were classified.
Next, the defect images and defect type classification results before and after hydrofluoric acid cleaning were compared.
FIG. 4 is a table showing defect examples 1 to 3.
Defect example 1 is a defect that was classified as a particle before the hydrofluoric acid cleaning and classified as a pit after the hydrofluoric acid cleaning, and was reclassified as an oxygen precipitate.
Defect example 2 is a defect that was classified as a pit before the hydrofluoric acid cleaning and was also classified as a pit after the hydrofluoric acid cleaning, and the inner diameter of the pit after the hydrofluoric acid cleaning was larger than before the cleaning, and this defect was also reclassified as an oxygen precipitate.
Defect example 3 is a defect that was classified as a particle before cleaning with hydrofluoric acid and was classified as a particle after cleaning with hydrofluoric acid, and was determined to be a particle.
Next, oxide breakdown voltage degradation defects (pits, oxygen precipitates, scratches) were extracted, a pseudo oxide breakdown voltage degradation map (Fig. 3B) was created, and the GOI failure rate was calculated to be 3.3%. Since the failure rate was 2% or more, the sample was judged to be unacceptable.
For the other wafer, the GOI measurement was actually carried out, and the GOI defect rate was calculated from the obtained oxide film breakdown voltage degradation map (FIG. 3A), resulting in a value of 3.5%.
From this, the evaluation results of the present invention and the actual GOI measurement results were almost the same, proving that the pass/fail judgment of silicon single crystal substrates based on the evaluation results of the present invention is correct.
（比較例１）
実施例２の走査型電子顕微鏡観察結果から、欠陥種を、ＣＯＰ、加工ピット、ＰＩＤ、パーティクルに分類し、各欠陥種の欠陥数をカウントした。また、特許文献１に記載のＧＯＩ不良率の加重平均値と、各欠陥種の欠陥数を積算し、ＧＯＩ不良欠陥数を算出した。
最後に、ＧＯＩ不良欠陥数を合算し、ＧＯＩ測定セル数（３０００点）で除算したところ、（推定）ＧＯＩ不良率は１．３％となった。図５は、比較例１の実験結果である欠陥種（欠陥種類）、ＧＯＩ不良率の加重平均値、欠陥数、ＧＯＩ不良欠陥数、（推定）ＧＯＩ不良率を示す表である。
また、図６は、実施例１、２の本技術で及びＧＯＩ測定結果から算出したＧＯＩ不良率と、従来技術で算出したＧＯＩ不良率（比較例１）を示す表である。
図６から把握できるように、実施例２のＧＯＩ測定結果から算出したＧＯＩ不良率と比較して、従来技術で算出したＧＯＩ不良率は小さく算出された。
(Comparative Example 1)
The defect types were classified into COP, processing pits, PIDs, and particles based on the results of the scanning electron microscope observation in Example 2, and the number of defects of each defect type was counted. In addition, the weighted average value of the GOI defect rate described in Patent Document 1 was multiplied by the number of defects of each defect type to calculate the number of GOI defects.
Finally, the total number of GOI failures was divided by the number of GOI measurement cells (3,000 points), resulting in an (estimated) GOI failure rate of 1.3%. Figure 5 is a table showing the experimental results of Comparative Example 1, including defect types, weighted average GOI failure rates, number of defects, number of GOI failures, and (estimated) GOI failure rate.
FIG. 6 is a table showing the GOI defect rates calculated from the GOI measurement results using the present technology in Examples 1 and 2, and the GOI defect rate calculated using the conventional technology (Comparative Example 1).
As can be seen from FIG. 6, the GOI defect rate calculated using the conventional technology was smaller than the GOI defect rate calculated from the GOI measurement results of Example 2.
以上のとおり、本発明の実施例によれば、簡便に、高精度に酸化膜耐圧特性を評価でき、簡便に、高精度にシリコン単結晶基板の合否を判定することができた。 As described above, according to the embodiments of the present invention, it is possible to easily and accurately evaluate the oxide film breakdown voltage characteristics and easily and accurately determine the pass/fail status of silicon single crystal substrates.
本明細書は、以下の態様を包含する。
［１］：シリコン単結晶基板の酸化膜耐圧特性の評価方法であって、シリコン単結晶基板における欠陥を表面欠陥検査装置で検出し、欠陥座標を取得する第１工程と、前記欠陥座標を基に走査型電子顕微鏡で前記シリコン単結晶基板の欠陥を観察し、欠陥像を取得し、欠陥種を分類する第２工程と、前記シリコン単結晶基板をフッ酸で洗浄する第３工程と、前記フッ酸洗浄後に、前記第１工程で取得した前記欠陥座標を基に、走査型電子顕微鏡で欠陥を観察し、欠陥像を取得し、欠陥種を分類する第４工程と、前記第２工程及び前記第４工程で取得した欠陥像及び欠陥種を比較して酸素析出物を抽出する第５工程と、前記第１乃至第５工程から酸化膜耐圧劣化の原因となる欠陥を抽出し、前記酸化膜耐圧劣化欠陥の座標を基に擬似的な酸化膜耐圧劣化マップを作成する第６工程と、を有することを特徴とするシリコン単結晶基板の酸化膜耐圧特性の評価方法。
［２］： 前記第２、第４工程で分類する前記欠陥種を、パーティクル、ピット、スクラッチ、ＰＩＤとすることを特徴とする上記［１］に記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法。
［３］： 前記酸素析出物を抽出する第５工程において、前記第２工程でパーティクルに分類され、前記第４工程でピットに分類された欠陥を酸素析出物に再分類するとともに、前記第２工程でピットに分類され、前記第４工程でピットとして分類された欠陥のうち、前記第４工程のピットの深さが前記第２工程よりも深い欠陥又は前記第４工程のピットの内径が前記第２工程よりも大きい欠陥を酸素析出物に再分類することを特徴とする上記［１］または上記［２］に記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法。
［４］： 前記酸化膜耐圧劣化の原因となる欠陥を、ピット、酸素析出物、スクラッチとすることを特徴とする上記［１］～上記［３］のいずれかに記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法。
［５］： 上記［１］～上記［４］のいずれかに記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法を用いたシリコン単結晶基板の合否判定方法であって、前記第６工程で作成した前記擬似的な酸化膜耐圧劣化マップから、酸化膜耐圧不良率を算出し、予め設定した所定の酸化膜耐圧不良率を超えた場合に、前記シリコン単結晶基板を不合格と判定することを特徴とするシリコン単結晶基板の合否判定方法。
The present specification includes the following aspects.
[1]: A method for evaluating oxide film breakdown characteristics of a silicon single crystal substrate, comprising: a first step of detecting defects in the silicon single crystal substrate using a surface defect inspection device and acquiring defect coordinates; a second step of observing the defects in the silicon single crystal substrate using a scanning electron microscope based on the defect coordinates, acquiring defect images, and classifying the defect types; a third step of cleaning the silicon single crystal substrate with hydrofluoric acid; a fourth step of observing the defects using a scanning electron microscope based on the defect coordinates acquired in the first step after the hydrofluoric acid cleaning, acquiring defect images, and classifying the defect types; a fifth step of comparing the defect images and defect types acquired in the second step and the fourth step to extract oxygen precipitates; and a sixth step of extracting defects that cause oxide film breakdown characteristics degradation from the first to fifth steps, and creating a pseudo oxide film breakdown characteristics degradation map based on the coordinates of the oxide film breakdown degradation defects.
[2]: The method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to the above [1], characterized in that the defect types classified in the second and fourth steps are particles, pits, scratches, and PIDs.
[3]: A method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to [1] or [2] above, characterized in that in the fifth step of extracting the oxygen precipitates, defects classified as particles in the second step and as pits in the fourth step are reclassified as oxygen precipitates, and among the defects classified as pits in the second step and as pits in the fourth step, defects whose pit depth in the fourth step is deeper than in the second step or whose inner diameter in the fourth step is larger than in the second step are reclassified as oxygen precipitates.
[4]: A method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to any one of [1] to [3] above, characterized in that the defects that cause the deterioration of the oxide film breakdown voltage are pits, oxygen precipitates, or scratches.
[5]: A method for determining the acceptability of a silicon single crystal substrate using the method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to any one of [1] to [4] above, characterized in that an oxide film breakdown voltage defect rate is calculated from the pseudo oxide film breakdown voltage degradation map created in the sixth step, and when the oxide film breakdown voltage defect rate exceeds a predetermined predetermined value, the silicon single crystal substrate is determined to be unacceptable.
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-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical concept described in the claims of the present invention and that provides similar effects is within the technical scope of the present invention.
Claims (5)
シリコン単結晶基板における欠陥を表面欠陥検査装置で検出し、欠陥座標を取得する第１工程と、
前記欠陥座標を基に走査型電子顕微鏡で前記シリコン単結晶基板の欠陥を観察し、欠陥像を取得し、欠陥種を分類する第２工程と、
前記シリコン単結晶基板をフッ酸で洗浄する第３工程と、
前記フッ酸洗浄後に、前記第１工程で取得した前記欠陥座標を基に、走査型電子顕微鏡で欠陥を観察し、欠陥像を取得し、欠陥種を分類する第４工程と、
前記第２工程及び前記第４工程で取得した欠陥像及び欠陥種を比較して酸素析出物を抽出する第５工程と、
前記第１乃至第５工程から酸化膜耐圧劣化の原因となる欠陥を抽出し、該酸化膜耐圧劣化の原因となる欠陥の座標を基に擬似的な酸化膜耐圧劣化マップを作成する第６工程と、を有することを特徴とするシリコン単結晶基板の酸化膜耐圧特性の評価方法。 A method for evaluating oxide film breakdown voltage characteristics of a silicon single crystal substrate, comprising:
a first step of detecting defects in a silicon single crystal substrate using a surface defect inspection device and acquiring defect coordinates;
a second step of observing the defects in the silicon single crystal substrate with a scanning electron microscope based on the defect coordinates, acquiring defect images, and classifying the defect types;
a third step of cleaning the silicon single crystal substrate with hydrofluoric acid;
a fourth step of observing the defects with a scanning electron microscope based on the defect coordinates obtained in the first step after the hydrofluoric acid cleaning, obtaining defect images, and classifying the defect types;
a fifth step of comparing the defect images and defect types acquired in the second step and the fourth step to extract oxygen precipitates;
a sixth step of extracting defects that cause degradation of the oxide film breakdown voltage from the first to fifth steps, and creating a pseudo oxide film breakdown voltage degradation map based on the coordinates of the defects that cause the degradation of the oxide film breakdown voltage.
前記第２工程でパーティクルに分類され、前記第４工程でピットに分類された欠陥を酸素析出物に再分類するとともに、
前記第２工程でピットに分類され、前記第４工程でピットとして分類された欠陥のうち、前記第４工程のピットの深さが前記第２工程よりも深い欠陥又は前記第４工程のピットの内径が前記第２工程よりも大きい欠陥を酸素析出物に再分類することを特徴とする請求項１に記載のシリコン単結晶基板の酸化膜耐圧特性の評価方法。 In the fifth step of extracting the oxygen precipitates,
Reclassifying the defects classified as particles in the second step and as pits in the fourth step into oxygen precipitates;
2. The method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to claim 1, wherein, among the defects classified as pits in the second step and as pits in the fourth step, defects whose pit depth in the fourth step is deeper than in the second step or whose inner diameter in the fourth step is larger than in the second step are reclassified as oxygen precipitates.
前記第６工程で作成した前記擬似的な酸化膜耐圧劣化マップから、酸化膜耐圧不良率を算出し、
予め設定した所定の酸化膜耐圧不良率を超えた場合に、前記シリコン単結晶基板を不合格と判定することを特徴とするシリコン単結晶基板の合否判定方法。
A method for determining whether a silicon single crystal substrate is acceptable or not, using the method for evaluating the oxide film breakdown voltage characteristics of a silicon single crystal substrate according to any one of claims 1 to 4,
calculating a failure rate of oxide film breakdown voltage from the pseudo oxide film breakdown voltage degradation map created in the sixth step;
A method for determining whether a silicon single crystal substrate is acceptable or not, comprising determining that the silicon single crystal substrate is unacceptable when a predetermined oxide film breakdown voltage defect rate is exceeded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022140241A JP7729290B2 (en) | 2022-09-02 | 2022-09-02 | Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022140241A JP7729290B2 (en) | 2022-09-02 | 2022-09-02 | Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2024035650A JP2024035650A (en) | 2024-03-14 |
| JP7729290B2 true JP7729290B2 (en) | 2025-08-26 |
Family
ID=90194762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2022140241A Active JP7729290B2 (en) | 2022-09-02 | 2022-09-02 | Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7729290B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120009323B (en) * | 2025-04-14 | 2025-08-05 | 合肥众波功能材料有限公司 | Piezoelectric single crystal micromorphology detection method and system based on SEM |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006040961A (en) | 2004-07-22 | 2006-02-09 | Shin Etsu Handotai Co Ltd | Inspecting method, manufacturing method and managing method of semiconductor wafer |
| JP2020106399A (en) | 2018-12-27 | 2020-07-09 | 株式会社Sumco | Semiconductor wafer evaluation method and manufacturing method, and semiconductor wafer manufacturing process control method |
| JP2020161555A (en) | 2019-03-25 | 2020-10-01 | 信越半導体株式会社 | Evaluation method of oxide film breakdown voltage characteristic of silicon wafer and manufacturing process management method of the silicon wafer |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62256448A (en) * | 1986-04-30 | 1987-11-09 | Oki Electric Ind Co Ltd | Detection of defect in silicon substrate |
| JP2948119B2 (en) * | 1995-03-09 | 1999-09-13 | 三菱マテリアル株式会社 | Method for detecting octahedral oxygen precipitates near the surface of silicon wafers |
| JP2951869B2 (en) * | 1995-05-01 | 1999-09-20 | 三菱マテリアルシリコン株式会社 | Method for detecting growth defects in single crystal silicon |
| JP3862116B2 (en) * | 1997-11-07 | 2006-12-27 | コマツ電子金属株式会社 | Quality evaluation method of semiconductor wafer polishing using silicon wafer |
-
2022
- 2022-09-02 JP JP2022140241A patent/JP7729290B2/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006040961A (en) | 2004-07-22 | 2006-02-09 | Shin Etsu Handotai Co Ltd | Inspecting method, manufacturing method and managing method of semiconductor wafer |
| JP2020106399A (en) | 2018-12-27 | 2020-07-09 | 株式会社Sumco | Semiconductor wafer evaluation method and manufacturing method, and semiconductor wafer manufacturing process control method |
| JP2020161555A (en) | 2019-03-25 | 2020-10-01 | 信越半導体株式会社 | Evaluation method of oxide film breakdown voltage characteristic of silicon wafer and manufacturing process management method of the silicon wafer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2024035650A (en) | 2024-03-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6952492B2 (en) | Method and apparatus for inspecting a semiconductor device | |
| JP2011124354A (en) | Inspection method of soi wafer | |
| TW201708811A (en) | Semiconductor wafer evaluation method | |
| US5946543A (en) | Semiconductor wafer evaluating method and semiconductor device manufacturing method | |
| JP2000058509A (en) | Crystal defect evaluation method and crystal defect evaluation device | |
| JP7729290B2 (en) | Method for evaluating oxide film breakdown voltage characteristics of silicon single crystal substrates and method for determining pass/fail of silicon single crystal substrates | |
| JPH06295945A (en) | Method and device for evaluating semiconductor manufacturing process | |
| TW462100B (en) | Wafer surface inspection method | |
| JP2008113027A (en) | Method of manufacturing device | |
| JP3862116B2 (en) | Quality evaluation method of semiconductor wafer polishing using silicon wafer | |
| US7799655B2 (en) | Method for evaluation of bonded wafer | |
| CN111710618B (en) | Method for detecting defects of passivation layer of wafer | |
| JP7140022B2 (en) | Evaluation method of oxide film withstand voltage characteristics of silicon wafer and method of manufacturing process control of silicon wafer | |
| JP2006040961A (en) | Inspecting method, manufacturing method and managing method of semiconductor wafer | |
| JP2001015567A (en) | Apparatus and method for evaluating semiconductor substrate | |
| JP2000114333A (en) | Silicon wafer surface fine defect evaluation method | |
| US7855088B2 (en) | Method for manufacturing integrated circuits by guardbanding die regions | |
| US5990022A (en) | Method of evaluating a silicon wafer | |
| JPH1174493A (en) | SOI wafer defect inspection method | |
| JP4908885B2 (en) | Semiconductor device characteristic prediction method and characteristic prediction apparatus | |
| CN119688427B (en) | Silicon carbide wafer and high-accuracy silicon carbide wafer dislocation detection method | |
| JP2005228848A (en) | Method for inspecting and manufacturing simox wafer | |
| JP6471710B2 (en) | Single crystal wafer evaluation method | |
| KR100817082B1 (en) | Surface Uniformity Evaluation System and Its Evaluation Method | |
| US7453280B1 (en) | Method for testing semiconductor devices |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20240918 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20250530 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20250603 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20250708 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20250715 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20250728 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7729290 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |