Apparatus for cutting semiconductor crystal

An apparatus for cutting a semiconductor crystal, comprising:

• a rotary blade of a generally disk shape including an inside diameter saw having abrasive grains deposited along an inner periphery thereof;
• rotary chuck means fixed holding said blade for rotation therewith;
• position indicating means for indicating a position corresponding to a prescribed point on said blade, said position indicating means consisting of a mark on said rotary chuck means;
• a first sensor stationarily located in opposed relation to said abrasive grains on said blade for sensing a distance between said blade and said first sensor to produce a first signal representative of said distance;
• a second sensor stationarily disposed in opposed relation to said rotary chuck means for detecting said position of said position indicating means to produce a second signal representative of said prescribed point on said blade;
• computing means connected to said first and second sensors for receiving said first signal from said first sensor in synchronization with said second signal from said second sensor, and computing an amount of warp of said blade as to a fixed position thereof by using said received first signal, said computing means including a memory for storing as initial data said first signal initially inputted from said first sensor, and processing means for retrieving said stored initial data from said memory and comparing said initial data with said first signal subsequently imputted from said first sensor to thereby calculate said amount of warp of said blade;
• command means connected to said computing means for producing a command signal to start the cutting operation, and inputting said command signal to said computing means to cause said computing means to receive said first signal from said first sensor after said command signal is inputted thereto;
• and
• recording means connected to said computing means for recording the amount of warp computed in said computing means.