JP2008132559A - Grinding method for silicon carbide single crystal - Google Patents

Grinding method for silicon carbide single crystal Download PDF

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JP2008132559A
JP2008132559A JP2006319791A JP2006319791A JP2008132559A JP 2008132559 A JP2008132559 A JP 2008132559A JP 2006319791 A JP2006319791 A JP 2006319791A JP 2006319791 A JP2006319791 A JP 2006319791A JP 2008132559 A JP2008132559 A JP 2008132559A
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single crystal
silicon carbide
carbide single
grinding
grinding wheel
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Masao Nakamura
昌生 中村
Erumu Nitta
永留夢 新田
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Bridgestone Corp
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Bridgestone Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding method for silicon carbide single crystal for easily and efficiently cutting out silicon carbide single crystal having no breakage such as crack. <P>SOLUTION: This grinding method comprises a process for bringing a grindstone working part 32 of a grinding wheel 30 into contact with a growth face opposing to a seed crystal 11 side of the silicon carbide single crystal 10 formed by the sublimation method, and a process for grinding the silicon carbide single crystal 10 by rotating the grinding wheel 30 and lowering the grinding wheel 30 in the direction of seed crystal 11. Ultrasonic vibration is given to the hollow cylindrical grinding wheel 30 or a fixed device 21 to discharge facet pieces of the silicon carbide single crystal 10 in the process for grinding the silicon carbide single crystal 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、炭化ケイ素単結晶の研削方法に関し、詳しくは加工時に割れや欠けなどの発生することのない炭化ケイ素単結晶の研削方法に関する。   The present invention relates to a method for grinding a silicon carbide single crystal, and more particularly to a method for grinding a silicon carbide single crystal that does not generate cracks or chips during processing.

炭化ケイ素は、ケイ素に比し、バンドギャップが大きく、絶縁破壊特性、耐熱性、耐放射線性等に優れることから、小型で高出力の半導体等の電子デバイス材料として注目されている。また、炭化ケイ素は、光学的特性に優れた他の化合物半導体との接合性に優れることから、光学デバイス材料としても注目されてきている。   Silicon carbide is attracting attention as a small and high-power electronic device material such as a semiconductor because it has a larger band gap and is superior in dielectric breakdown characteristics, heat resistance, radiation resistance, and the like. In addition, silicon carbide has been attracting attention as an optical device material because it has excellent bonding properties with other compound semiconductors having excellent optical characteristics.

炭化ケイ素単結晶ウェハの製造方法の一態様として、坩堝内に昇華用原料粉を封入し、対向する側に配置された種結晶上に昇華ガスを供給しつつ、種結晶上に炭化ケイ素単結晶を再結晶させ（昇華法）、得られた炭化ケイ素単結晶からウェハを切り出す方法がある。かかるウェハの切り出し法としては、円盤状の砥石を回転させて砥石の外周面を研削面として単結晶側面部に押し当てて単結晶を切り出す方法が提案されている（特許文献１参照）。
特開２００１−２６１４９１号公報 As one aspect of a method for producing a silicon carbide single crystal wafer, a raw material powder for sublimation is enclosed in a crucible, and a sublimation gas is supplied onto a seed crystal disposed on the opposite side, while a silicon carbide single crystal is formed on the seed crystal. Is recrystallized (sublimation method), and a wafer is cut out from the obtained silicon carbide single crystal. As a method for cutting out such a wafer, there has been proposed a method of cutting a single crystal by rotating a disk-shaped grindstone and pressing the outer peripheral surface of the grindstone against a side surface of the single crystal as a grinding surface (see Patent Document 1).
JP 2001-261491 A

しかしながら、単結晶成長表面の周縁部、特に坩堝との接触面外周部分に螺旋転位などの結晶欠陥が発生しやすく、円筒研削を行うとかかる欠陥部分にクラックが発生しやすかった。この結果、単結晶表面までクラックが進行して使い物にならないなど、加工方法に関してはいまだ十分な加工方法が提案されていなかった。   However, crystal defects such as screw dislocations are liable to occur at the peripheral portion of the single crystal growth surface, particularly the outer peripheral portion of the contact surface with the crucible, and cracks are liable to occur when cylindrical grinding is performed. As a result, a sufficient processing method has not been proposed yet regarding the processing method, such as cracks reaching the surface of the single crystal and making it unusable.

炭化ケイ素単結晶を効率よく、かつ割れ等の破損がない状態で容易に切り出すことができる炭化ケイ素単結晶の研削方法が求められていた。   There has been a demand for a grinding method of a silicon carbide single crystal that can efficiently cut out a silicon carbide single crystal without causing breakage such as cracks.

本発明に係る炭化ケイ素単結晶の研削方法は、昇華法により形成された炭化ケイ素単結晶の種結晶側に対向する成長面に対して中空円筒状砥石の開口加工部を接触させる工程と、中空円筒状砥石を回転させると共に中空円筒状砥石を種結晶方向に下降させて炭化ケイ素単結晶を研削する工程とを含み、炭化ケイ素単結晶を研削する工程にて、中空円筒状砥石に超音波振動を与えて炭化ケイ素単結晶の切子を排出させる。   The method for grinding a silicon carbide single crystal according to the present invention includes a step of contacting an opening processing portion of a hollow cylindrical grindstone with a growth surface facing a seed crystal side of a silicon carbide single crystal formed by a sublimation method, A step of grinding the silicon carbide single crystal by rotating the cylindrical grindstone and lowering the hollow cylindrical grindstone in the seed crystal direction, and ultrasonically vibrating the hollow cylindrical grindstone in the step of grinding the silicon carbide single crystal. To discharge the silicon carbide single crystal facets.

本発明に係る他の炭化ケイ素単結晶の研削方法は、昇華法により形成された炭化ケイ素単結晶を固定装置に固定し、当該炭化ケイ素単結晶の種結晶側に対向する成長面に対して中空円筒状砥石の開口加工部を接触させる工程と、中空円筒状砥石を回転させると共に中空円筒状砥石を種結晶方向に下降させて炭化ケイ素単結晶を研削する工程とを含み、炭化ケイ素単結晶を研削する工程にて、炭化ケイ素単結晶の固定装置に超音波振動を与えて炭化ケイ素単結晶の切子を排出させる。   Another method of grinding a silicon carbide single crystal according to the present invention is to fix a silicon carbide single crystal formed by a sublimation method to a fixing device and to be hollow with respect to a growth surface facing the seed crystal side of the silicon carbide single crystal. A step of contacting the opening processing portion of the cylindrical grindstone, and a step of rotating the hollow cylindrical grindstone and lowering the hollow cylindrical grindstone in the seed crystal direction to grind the silicon carbide single crystal. In the grinding step, ultrasonic vibration is applied to the silicon carbide single crystal fixing device to discharge the silicon carbide single crystal facets.

また、この炭化ケイ素単結晶の研削方法は、炭化ケイ素単結晶を研削する工程にて、１５ｋＨｚ〜１００ｋＨｚの超音波振動を与えることが望ましい。   Moreover, as for this grinding method of a silicon carbide single crystal, it is desirable to give an ultrasonic vibration of 15 kHz-100 kHz in the process of grinding a silicon carbide single crystal.

更に、この炭化ケイ素単結晶の研削方法は、炭化ケイ素単結晶を研削する工程にて、振幅が１０μｍ〜４０μｍの超音波振動を与えることが望ましい。   Furthermore, in this method for grinding a silicon carbide single crystal, it is desirable to apply ultrasonic vibration having an amplitude of 10 μm to 40 μm in the step of grinding the silicon carbide single crystal.

本発明に係る炭化ケイ素単結晶の研削方法によれば、炭化ケイ素単結晶を研削する工程にて、超音波振動によって炭化ケイ素単結晶の切子を排出させるので、炭化ケイ素単結晶の割れ等の破損がない状態で容易に切り出すことができる。   According to the method for grinding a silicon carbide single crystal according to the present invention, in the step of grinding the silicon carbide single crystal, since the silicon carbide single crystal facets are discharged by ultrasonic vibration, the silicon carbide single crystal is broken or broken. It can be easily cut out in the absence of

以下に実施形態を挙げて本発明を説明するが、本発明が以下の実施形態に限定されないことはいうまでもない。   Hereinafter, the present invention will be described with reference to embodiments, but it goes without saying that the present invention is not limited to the following embodiments.

本発明を適用した炭化ケイ素単結晶の研削方法は、図１（ａ）、（ｂ）に示すように固定装置２１及び坩堝の蓋２０上に固定された炭化ケイ素単結晶１０を、図２，３，４に示すような研削砥石３０を用いて研削する。固定装置２１は、炭素からなる板状部材である。以下に説明する炭化ケイ素単結晶１０の研削方法は、炭化ケイ素単結晶１０の研削工程において、超音波振動によって炭化ケイ素単結晶１０の切り子の排出効率を高めることを特徴としている。   The method of grinding a silicon carbide single crystal to which the present invention is applied includes a silicon carbide single crystal 10 fixed on a fixing device 21 and a crucible lid 20 as shown in FIGS. 1 (a) and 1 (b). Grinding is performed using a grinding wheel 30 as shown in FIGS. The fixing device 21 is a plate-like member made of carbon. The silicon carbide single crystal 10 grinding method described below is characterized in that in the grinding process of the silicon carbide single crystal 10, the cutting efficiency of the silicon carbide single crystal 10 is increased by ultrasonic vibration.

（研削砥石）
本発明の実施形態にかかる炭化ケイ素単結晶の研削方法に用いられる研削砥石３０を装着する研削装置としては、研削砥石３０の回転機能と上下動機能を備えるものであれば特に制限はない。 (Grinding wheel)
The grinding apparatus for mounting the grinding wheel 30 used in the method for grinding a silicon carbide single crystal according to the embodiment of the present invention is not particularly limited as long as it has the rotation function and the vertical movement function of the grinding wheel 30.

具体的には、図２に示すように、研削砥石３０は、回転駆動される砥石シャンク３１と、炭化ケイ素単結晶１０を研削する時に当該炭化ケイ素単結晶１０に接触する砥石加工部３２とが接続されて構成されている。   Specifically, as shown in FIG. 2, the grinding wheel 30 includes a grindstone shank 31 that is rotationally driven and a grindstone processing unit 32 that contacts the silicon carbide single crystal 10 when the silicon carbide single crystal 10 is ground. Connected and configured.

砥石加工部３２は、円状の開口を有し、炭化ケイ素単結晶１０を研削加工する開口加工部となっている。この砥石加工部３２は、ダイヤモンド砥粒及び、樹脂などの結合剤から形成されている。砥石シャンク３１は、研削装置の回転駆動機構に接続されおり、当該回転駆動機構の回転力が与えられる。この砥石シャンク３１が回転されると、研削砥石３０及び砥石加工部３２も回転される。   The grindstone processing portion 32 has a circular opening and is an opening processing portion for grinding the silicon carbide single crystal 10. This grindstone processing part 32 is formed from a binder such as diamond abrasive grains and resin. The grindstone shank 31 is connected to the rotational drive mechanism of the grinding apparatus, and is given the rotational force of the rotational drive mechanism. When the grindstone shank 31 is rotated, the grinding wheel 30 and the grindstone processing unit 32 are also rotated.

このような研削砥石３０は、中心軸Ｚに沿って上下動する（Ｚ軸方向とする）。駆動部の図示は省略してある。中空円筒状の砥石加工部３２の断面内法直径は、図４（ａ）に示すように、単結晶領域１２を囲むに十分な内法径を有することが好ましい。研削砥石３０は、砥石加工部３２の開口部に、切り欠部が一定間隔で設けられていることが好ましい。加工屑が欠き出されやすくなり研削抵抗が低減するからである。また研削砥石３０は、図４（ａ）の一部断面図に示すように、砥石シャンク３１の中心軸Ｚ上に水等の潤滑剤を供給する噴出し口（センタースルー）３４を備えることが好ましい。加工点の温度上昇を防止すると共に水流３５により加工屑を吐き出すことで研削抵抗を低下させることができるからである。   Such a grinding wheel 30 moves up and down along the central axis Z (the Z-axis direction). The illustration of the drive unit is omitted. As shown in FIG. 4A, it is preferable that the hollow cylinder-shaped grindstone processing portion 32 has a sufficient internal diameter to surround the single crystal region 12 as shown in FIG. The grinding wheel 30 is preferably provided with notches at regular intervals in the opening of the grindstone processing section 32. This is because the machining waste is easily cut out and the grinding resistance is reduced. Further, as shown in the partial cross-sectional view of FIG. 4A, the grinding wheel 30 includes an ejection port (center through) 34 for supplying a lubricant such as water onto the central axis Z of the grinding wheel shank 31. preferable. This is because the grinding resistance can be lowered by preventing the temperature rise at the processing point and discharging the processing waste by the water flow 35.

図４に示す研削砥石３０又は固定装置２１に超音波振動を与えた場合、超音波のキャビテーション現象によって加工屑がスムーズに排出される。超音波の振動方向としては、回転軸方向が一般的ではあるが、この回転軸と直交する何れの軸方向であっても加工屑の排出効果を得ることができる。図中で左右方向に振動させた場合には、図４（ｂ）に示すように静止時の砥石シャンク３１の中心軸Ｚと炭化ケイ素単結晶１０の中心位置ＺＬ１とが、距離Ｌだけずれるようになる。これにより、加工屑が切り欠部から排出される効率を、円形状とした場合よりも高くすると考えることができる。この距離Ｌは、図４（ｂ）では大きく示しているが、実際には、振幅が１０μｍ〜４０μｍの超音波振動を与えるために、当該１０μｍ〜４０μｍである。また、超音波振動の周波数は、１５ｋＨｚ〜１００ｋＨｚであることが望ましい。なお、図４（ｂ）のＡ−Ａ線で切った断面図が図５（ａ）となっている。   When ultrasonic vibration is applied to the grinding wheel 30 or the fixing device 21 shown in FIG. 4, the machining waste is smoothly discharged by the ultrasonic cavitation phenomenon. As the vibration direction of the ultrasonic wave, the rotation axis direction is generally used, but the removal effect of the machining waste can be obtained in any axial direction orthogonal to the rotation axis. When it is vibrated in the left-right direction in the figure, the center axis Z of the grinding wheel shank 31 at rest and the center position ZL1 of the silicon carbide single crystal 10 are shifted by a distance L as shown in FIG. become. Thereby, it can be considered that the efficiency with which the processing waste is discharged from the notch is higher than that in the case of a circular shape. Although this distance L is greatly shown in FIG. 4B, in reality, the distance L is 10 μm to 40 μm in order to apply ultrasonic vibration having an amplitude of 10 μm to 40 μm. The frequency of the ultrasonic vibration is desirably 15 kHz to 100 kHz. A cross-sectional view taken along the line AA in FIG. 4B is FIG. 5A.

研削砥石３０を用い炭化ケイ素単結晶１０を加工する場合において加工屑によって研削砥石３０が目詰まりを起こし、研削砥石３０のブレによって発生する炭化ケイ素単結晶１０のクラックを超音波振動の付与により抑制できうる。   When the silicon carbide single crystal 10 is processed using the grinding wheel 30, the grinding wheel 30 is clogged by processing scraps, and cracks of the silicon carbide single crystal 10 generated by the shaking of the grinding wheel 30 are suppressed by applying ultrasonic vibration. It can be done.

研削砥石３０に超音波振動を与える構成としては、発振子と超音波発生装置を用意し、当該超音波発生装置で発生した超音波信号に従って発振子で超音波振動を発生させて、砥石シャンク３１を介して研削砥石３０及び砥石加工部３２に超音波振動を与えることによって、炭化ケイ素単結晶１０の切子及び加工液に超音波振動を与える。同様に、固定装置２１に超音波振動を与える構成としては、発振子と超音波発生装置を用意し、当該超音波発生装置で発生した超音波信号に従って発振子で超音波振動を発生させて、超音波振動子を接触させて固定装置２１に超音波振動を与えることによって、炭化ケイ素単結晶１０の切子及び加工液に超音波振動を与える。   As a configuration for applying ultrasonic vibration to the grinding wheel 30, an oscillator and an ultrasonic generator are prepared, and ultrasonic vibration is generated by the oscillator in accordance with an ultrasonic signal generated by the ultrasonic generator, and the grindstone shank 31 is provided. By applying ultrasonic vibration to the grinding wheel 30 and the grindstone processing part 32 through the ultrasonic wave, ultrasonic vibration is applied to the facets and processing liquid of the silicon carbide single crystal 10. Similarly, as a configuration for applying ultrasonic vibration to the fixing device 21, an oscillator and an ultrasonic generator are prepared, and ultrasonic vibration is generated by the oscillator in accordance with an ultrasonic signal generated by the ultrasonic generator. By applying ultrasonic vibration to the fixing device 21 by bringing the ultrasonic vibrator into contact, ultrasonic vibration is applied to the facets and processing liquid of the silicon carbide single crystal 10.

図１〜図７を参照して炭化ケイ素単結晶の研削方法を説明する。   A method for grinding a silicon carbide single crystal will be described with reference to FIGS.

（イ）まず図１（ａ）に示す坩堝の蓋２０上に成長した炭化ケイ素単結晶１０を用意し、蓋２０面を固定装置２１上に配置し固定する。炭化ケイ素単結晶１０は図１（ｂ）の断面図に示すように単結晶領域１２が炭化ケイ素単結晶の成長方向に向かって除々に径が拡がっているものが好ましい。 (A) First, the silicon carbide single crystal 10 grown on the crucible lid 20 shown in FIG. 1A is prepared, and the lid 20 surface is arranged on the fixing device 21 and fixed. As shown in the cross-sectional view of FIG. 1B, the silicon carbide single crystal 10 preferably has a single crystal region 12 whose diameter gradually increases in the growth direction of the silicon carbide single crystal.

（ロ）次に図２及び図３に示すような砥石シャンク３１及び砥石加工部（刃）３２を備える研削砥石３０を用意する。 (B) Next, a grinding wheel 30 including a grinding wheel shank 31 and a grinding wheel processing portion (blade) 32 as shown in FIGS. 2 and 3 is prepared.

（ハ）そして図３に示すように、得たい炭化ケイ素単結晶１０の位置を、研削砥石３０の長手方向の中心軸に合わせる。図３において紙面左右方向をＸ方向、前後方向をＹ方向とする。 (C) Then, as shown in FIG. 3, the position of the silicon carbide single crystal 10 to be obtained is aligned with the central axis in the longitudinal direction of the grinding wheel 30. In FIG. 3, the left-right direction of the paper is the X direction, and the front-back direction is the Y direction.

（ニ）次に図４に示すように砥石シャンク３１を中心軸Ｚを中心に回転させて、研削砥石３０を回転させながら炭化ケイ素単結晶１０の種結晶方向１１に向けて所定速度で下降させて炭化ケイ素単結晶１０を研削する。このときの研削砥石３０の回転数は３００〜３０００ｒｐｍ、好ましくは５００〜１０００ｒｐｍである。回転数が３００ｒｐｍ未満では充分な研削効率を得ることができないからである。また回転数が３０００ｒｐｍを超えると砥石すべりが発生し加工が不安定になるからである。砥石の下方送り速度は０．１〜１．０ｍｍ／ｍｉｎが好ましい。下方送り速度が０．１ｍｍ／ｍｉｎ未満ではコスト高になるばかりでなく砥石すべりが発生するからである。下方送り速度が１．０ｍｍ／ｍｉｎを超えると、研削抵抗が上がりすぎ砥石の逃げやぶれが大きくなり、加工精度が悪くなるばかりかクラック誘発に繋がるからである。
図４（ａ）に示すように、上記回転及び上下動と併せて研削砥石３０の噴出し口３４から水流３５（潤滑剤）を吹きかけながら研削を行うことが好ましい。加工点の温度上昇を防止すると共に研削抵抗を低減できるからである。 (D) Next, as shown in FIG. 4, the grindstone shank 31 is rotated about the central axis Z, and the grindstone 30 is rotated at a predetermined speed toward the seed crystal direction 11 of the silicon carbide single crystal 10 while rotating. The silicon carbide single crystal 10 is ground. The rotation speed of the grinding wheel 30 at this time is 300 to 3000 rpm, preferably 500 to 1000 rpm. This is because sufficient grinding efficiency cannot be obtained when the rotational speed is less than 300 rpm. Further, if the rotational speed exceeds 3000 rpm, grinding wheel slip occurs and machining becomes unstable. The downward feed speed of the grindstone is preferably 0.1 to 1.0 mm / min. This is because when the downward feed speed is less than 0.1 mm / min, not only the cost is increased, but also grinding of the grindstone occurs. This is because when the downward feed speed exceeds 1.0 mm / min, the grinding resistance increases too much, and the grinding stones run away and sway, resulting in poor processing accuracy and lead to cracking.
As shown in FIG. 4A, it is preferable to perform grinding while spraying a water flow 35 (lubricant) from the outlet 34 of the grinding wheel 30 together with the above rotation and vertical movement. This is because it is possible to prevent the temperature rise at the processing point and reduce the grinding resistance.

このとき、研削砥石３０又は固定装置２１に超音波振動を与えているので、例えば研削砥石３０の噴出し口３４から水を噴き出した際に、研削砥石３０と非加工物との間に隙間を生じさせ、冷却水を加工点に供給しやすくなる。また図５に示すように加工屑１０ｂまで超音波振動が伝達し、加工屑１０ｂが吐き出されやすくなり、加工負荷の増大や研削砥石３０のブレを抑制できるという作用効果を奏する。   At this time, since the ultrasonic vibration is applied to the grinding wheel 30 or the fixing device 21, for example, when water is ejected from the ejection port 34 of the grinding wheel 30, a gap is formed between the grinding wheel 30 and the non-workpiece. This makes it easier to supply cooling water to the processing point. Further, as shown in FIG. 5, ultrasonic vibration is transmitted to the machining waste 10b, and the machining waste 10b is easily discharged, so that an increase in machining load and blurring of the grinding wheel 30 can be suppressed.

（ホ）次に図６，７に示す巻き取り部４１ａ、４１ｂと、巻き取り部４１ａ、４１ｂに把持されたワイヤー４２とを備えるシングルワイヤ４０を用意する。研削にはワイヤー４２としてダイヤモンドなどの砥粒がコーティングされたものを用いてもよく、またダイヤモンド砥粒を供給しつつ研削してもよい。そして図６に示すように、円柱状炭化ケイ素単結晶の成長表面近傍、即ち切り込み部の上端とシングルワイヤ４０を接触させる。そして、炭化ケイ素単結晶１０の単結晶領域１２に形成された円柱状炭化ケイ素単結晶の上部（成長表面近傍）を切断除去する。また図７に示すように、種結晶１１の上端とシングルワイヤ４０を接触させる。そして、炭化ケイ素単結晶１０の円柱状炭化ケイ素単結晶の下部（種結晶接着面近傍）を切断する。 (E) Next, a single wire 40 including winding portions 41a and 41b shown in FIGS. 6 and 7 and a wire 42 held by the winding portions 41a and 41b is prepared. For the grinding, a wire 42 coated with abrasive grains such as diamond may be used, or grinding may be performed while supplying diamond abrasive grains. Then, as shown in FIG. 6, the single wire 40 is brought into contact with the vicinity of the growth surface of the columnar silicon carbide single crystal, that is, the upper end of the cut portion. Then, the upper part (near the growth surface) of the cylindrical silicon carbide single crystal formed in the single crystal region 12 of the silicon carbide single crystal 10 is cut and removed. Further, as shown in FIG. 7, the upper end of the seed crystal 11 and the single wire 40 are brought into contact with each other. Then, the lower part (near the seed crystal bonding surface) of the cylindrical silicon carbide single crystal of the silicon carbide single crystal 10 is cut.

以上のようにして炭化ケイ素単結晶１０から円柱状の単結晶領域１０ａを切り出すことができる。尚、マルチワイヤ（図示せず）を用いて所定間隔で単結晶領域１０ａを切断することで所望のウェハ厚の炭化ケイ素単結晶ウェハが得られる。   The cylindrical single crystal region 10a can be cut out from the silicon carbide single crystal 10 as described above. Note that a silicon carbide single crystal wafer having a desired wafer thickness can be obtained by cutting the single crystal regions 10a at predetermined intervals using a multi-wire (not shown).

この炭化ケイ素単結晶の研削方法の実施例１及び比較例１として、研削対象としての６Ｈ型炭化ケイ素単結晶（成長高さ：１０ｍｍ、最大径：７５ｍｍ）について以下の条件で研削実験を行い、クラックの発生について目視観察を行った。そして同様の条件で研削を行った際に生じたクラックの回数をクラック発生率（％）として調べた。   As Example 1 and Comparative Example 1 of this silicon carbide single crystal grinding method, a grinding experiment was performed on a 6H type silicon carbide single crystal (growth height: 10 mm, maximum diameter: 75 mm) as a grinding object under the following conditions. Visual observation was performed on the occurrence of cracks. The number of cracks that occurred when grinding under the same conditions was examined as the crack generation rate (%).

（実施例１）
研削装置：グライディングセンター（三井精機製、商品名「VU６５」）、
研削砥石：内径５１．０ｍｍ、刃厚１．０ｍｍ、ダイヤモンド砥粒、粒径＃１４０、
研削条件：回転数１０００ｒｐｍ、送り速度０．３ｍｍ／ｍｉｎ、センタースルー圧力０．１７ＭＰａ、
結果：クラック発生率は２／２０回（１０％）であった。 (Example 1)
Grinding equipment: Gliding Center (Mitsui Seiki, trade name “VU65”),
Grinding wheel: inner diameter 51.0 mm, blade thickness 1.0 mm, diamond abrasive, particle size # 140,
Grinding conditions: rotation speed 1000 rpm, feed rate 0.3 mm / min, center through pressure 0.17 MPa,
Result: The crack occurrence rate was 2/20 times (10%).

（比較例１）
比較例として、円筒研削機（岡本工作機械社製、商品名「ＯＧＭ３４０ＵＥＸ」）を用いて、片側切り込み（切り込み量：１７．５ｍｍ、左右送り：９８ｍｍ／ｍｉｎ）、ワーク回転数１００ｒｐｍ、スパークアウト４往復の条件で研削加工を行ったことを除いて実施例１と同様の実験を行った。その結果、クラック発生率は５０／１００回（５０％）であった。 (Comparative Example 1)
As a comparative example, using a cylindrical grinding machine (trade name “OGM340UEX” manufactured by Okamoto Machine Tool Co., Ltd.), one-side cutting (cutting amount: 17.5 mm, left and right feed: 98 mm / min), workpiece rotation speed 100 rpm, spark out 4 An experiment similar to that in Example 1 was performed, except that grinding was performed under reciprocating conditions. As a result, the crack occurrence rate was 50/100 times (50%).

本発明の実施形態にかかる炭化ケイ素単結晶１０の研削方法によれば、高品質な炭化ケイ素単結晶１０を効率よく、かつ割れ等の破損がない状態で容易に切り出すことができる。すなわち、炭化ケイ素単結晶１０の外周部にクラックの基点となる欠陥が多く、当該外周部を削る必要がある場合であっても、上述の炭化ケイ素単結晶１０の研削方法によれば、炭化ケイ素単結晶１０の切り子を効率よく排出して研削砥石３０を炭化ケイ素単結晶１０から抜く時に切り子によって炭化ケイ素単結晶１０のクラックに繋がることを回避できる。   According to the method for grinding silicon carbide single crystal 10 according to the embodiment of the present invention, high-quality silicon carbide single crystal 10 can be easily cut out efficiently and without breakage such as cracks. That is, even if the outer periphery of the silicon carbide single crystal 10 has many defects that serve as the base point of cracks, the silicon carbide single crystal 10 is ground by the above-described grinding method. It is possible to efficiently discharge the facets of the single crystal 10 to avoid cracking of the silicon carbide single crystal 10 by the facets when the grinding wheel 30 is pulled out of the silicon carbide single crystal 10.

また、研削砥石３０を回転させた状態で研削砥石３０又は固定装置２１に超音波振動を与え、更に、研削砥石３０を揺動させることによって、加工速度を向上させることができる。この揺動は、炭化ケイ素単結晶１０と研削砥石３０を相対的に動かす。この揺動は、炭化ケイ素単結晶１０の成長方向の中心軸と、研削砥石３０の中心軸とのずれで定義される揺動幅が０．１〜１．０ｍｍとすることが望ましい。   Further, the processing speed can be improved by applying ultrasonic vibration to the grinding wheel 30 or the fixing device 21 in a state where the grinding wheel 30 is rotated and further swinging the grinding wheel 30. This rocking moves the silicon carbide single crystal 10 and the grinding wheel 30 relatively. As for this rocking | fluctuation, it is desirable for the rocking | fluctuation width | variety defined by the shift | offset | difference of the center axis | shaft of the growth direction of the silicon carbide single crystal 10 and the center axis | shaft of the grinding stone 30 to be 0.1-1.0 mm.

なお、研削対象となる炭化ケイ素単結晶１０としては、昇華法により製造されたものであれば特に制限されないが、多結晶や多型の混入やマイクロパイプ等の結晶欠陥がなく、極めて高品質なものが好ましい。半導体ウエハ等の電子デバイス、発光ダイオード等の光学デバイスなどに特に好適に用いることができるからである。具体的には、溶融アルカリによりエッチングして評価した結晶欠陥（パイプ欠陥）が、５０個／ｃｍ２以下のものが好ましく、１０個／ｃｍ２以下のものがより好ましい。炭化ケイ素単結晶１０における金属不純物元素の総含有量が１０ｐｐｍ以下のものが好ましい。 The silicon carbide single crystal 10 to be ground is not particularly limited as long as it is manufactured by a sublimation method, but there is no crystal defects such as polycrystals, polymorphs, micropipes, etc., and extremely high quality. Those are preferred. This is because it can be particularly suitably used for electronic devices such as semiconductor wafers, optical devices such as light emitting diodes, and the like. Specifically, the number of crystal defects (pipe defects) evaluated by etching with molten alkali is preferably 50 / cm 2 or less, and more preferably 10 / cm 2 or less. The total content of metal impurity elements in silicon carbide single crystal 10 is preferably 10 ppm or less.

（ａ）は炭化ケイ素単結晶の側面図を示し、（ｂ）は炭化ケイ素単結晶の断面図を示す。(A) shows the side view of a silicon carbide single crystal, (b) shows sectional drawing of a silicon carbide single crystal. 本発明にかかる炭化ケイ素単結晶の研削方法の工程図（その１）を示す。Process drawing (the 1) of the grinding method of the silicon carbide single crystal concerning this invention is shown. 本発明にかかる炭化ケイ素単結晶の研削方法の工程図（その２）を示す。Process drawing (the 2) of the grinding method of the silicon carbide single crystal concerning this invention is shown. （ａ）は本発明にかかる炭化ケイ素単結晶の研削方法の工程を示す断面図を示し、（ｂ）は研削砥石の一部断面図を示す。(A) shows sectional drawing which shows the process of the grinding method of the silicon carbide single crystal concerning this invention, (b) shows the partial sectional view of a grinding wheel. 本発明にかかる炭化ケイ素単結晶の研削方法の工程を示す断面拡大図を示す。The cross-sectional enlarged view which shows the process of the grinding method of the silicon carbide single crystal concerning this invention is shown. 本発明にかかる炭化ケイ素単結晶の研削方法の工程図（その３）を示す。Process drawing (the 3) of the grinding method of the silicon carbide single crystal concerning this invention is shown. 本発明にかかる炭化ケイ素単結晶の研削方法の工程図（その４）を示す。Process drawing (the 4) of the grinding method of the silicon carbide single crystal concerning this invention is shown.

符号の説明Explanation of symbols

１０…炭化ケイ素単結晶
１０ａ…単結晶領域
１０ｂ…加工屑
１１…種結晶
１２…単結晶領域
２０…蓋
２１…固定装置
３０…研削砥石
３１…砥石シャンク
３２…砥石加工部
３４…噴出し口
３５…水流
４０…シングルワイヤ
４２…ワイヤー
４１ａ、４１ｂ…巻き取り部 DESCRIPTION OF SYMBOLS 10 ... Silicon carbide single crystal 10a ... Single-crystal area | region 10b ... Processing waste 11 ... Seed crystal 12 ... Single-crystal area | region 20 ... Lid 21 ... Fixing device 30 ... Grinding wheel 31 ... Grinding wheel shank 32 ... Grinding wheel processing part 34 ... Outlet 35 ... Water stream 40 ... Single wire 42 ... Wire 41a, 41b ... Winding part

Claims (4)

昇華法により形成された炭化ケイ素単結晶の種結晶側に対向する成長面に対して中空円筒状砥石の開口加工部を接触させる工程と、
前記中空円筒状砥石を回転させると共に前記中空円筒状砥石を前記種結晶方向に下降させて前記炭化ケイ素単結晶を研削する工程とを含み、
前記炭化ケイ素単結晶を研削する工程にて、前記中空円筒状砥石に超音波振動を与えて前記炭化ケイ素単結晶の切子を排出させること
を特徴とする炭化ケイ素単結晶の研削方法。 A step of contacting the opening processed portion of the hollow cylindrical grindstone with the growth surface facing the seed crystal side of the silicon carbide single crystal formed by the sublimation method;
Rotating the hollow cylindrical grindstone and lowering the hollow cylindrical grindstone in the seed crystal direction to grind the silicon carbide single crystal,
A method for grinding a silicon carbide single crystal, wherein in the step of grinding the silicon carbide single crystal, ultrasonic vibration is applied to the hollow cylindrical grindstone to discharge the silicon carbide single crystal facets. 昇華法により形成された炭化ケイ素単結晶を固定装置に固定し、当該炭化ケイ素単結晶の種結晶側に対向する成長面に対して中空円筒状砥石の開口加工部を接触させる工程と、
前記中空円筒状砥石を回転させると共に前記中空円筒状砥石を前記種結晶方向に下降させて前記炭化ケイ素単結晶を研削する工程とを含み、
前記炭化ケイ素単結晶を研削する工程にて、前記炭化ケイ素単結晶の固定装置に超音波振動を与えて前記炭化ケイ素単結晶の切子を排出させること
を特徴とする炭化ケイ素単結晶の研削方法。 Fixing the silicon carbide single crystal formed by the sublimation method to a fixing device, and contacting the opening processing portion of the hollow cylindrical grindstone with the growth surface facing the seed crystal side of the silicon carbide single crystal;
Rotating the hollow cylindrical grindstone and lowering the hollow cylindrical grindstone in the seed crystal direction to grind the silicon carbide single crystal,
A method for grinding a silicon carbide single crystal, wherein in the step of grinding the silicon carbide single crystal, ultrasonic vibration is applied to a fixing device for the silicon carbide single crystal to discharge the facets of the silicon carbide single crystal. 前記炭化ケイ素単結晶を研削する工程にて、１５ｋＨｚ〜１００ｋＨｚの超音波振動を与えることを特徴とする請求項１又は請求項２に記載の炭化ケイ素単結晶の研削方法。   The method for grinding a silicon carbide single crystal according to claim 1 or 2, wherein ultrasonic vibration of 15 kHz to 100 kHz is applied in the step of grinding the silicon carbide single crystal. 前記炭化ケイ素単結晶を研削する工程にて、振幅が１０μｍ〜４０μｍの超音波振動を与えることを特徴とする請求項１又は請求項２に記載の炭化ケイ素単結晶の研削方法。   3. The method for grinding a silicon carbide single crystal according to claim 1, wherein in the step of grinding the silicon carbide single crystal, ultrasonic vibration having an amplitude of 10 μm to 40 μm is applied.
JP2006319791A 2006-11-28 2006-11-28 Grinding method for silicon carbide single crystal Pending JP2008132559A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009298659A (en) * 2008-06-13 2009-12-24 Bridgestone Corp Method for grinding silicon carbide single crystal
WO2011018925A1 (en) * 2009-08-11 2011-02-17 徳島県 Machining device, vibration device, and machining method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009298659A (en) * 2008-06-13 2009-12-24 Bridgestone Corp Method for grinding silicon carbide single crystal
WO2011018925A1 (en) * 2009-08-11 2011-02-17 徳島県 Machining device, vibration device, and machining method
JPWO2011018925A1 (en) * 2009-08-11 2013-01-17 徳島県 Processing device, vibration device and processing method
JP5660632B2 (en) * 2009-08-11 2015-01-28 徳島県 Processing device, vibration device and processing method

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