A chamfering grinding wheel and chamfering method for processing thick-layer epitaxial silicon single wafer

Abstract

The invention relates to a chamfering grinding wheel for machining a silicon single crystal wafer for thick-layer epitaxy, and a chamfering method. The diameters of coarse chamfering grooves of the grinding wheel are 120-150 micrometers less than the thickness of the wafer; half angles are 18-22 degrees; the depths are 900-1100 micrometers; the diamond sizes are 600-1000#; the diameters of fine chamfering grooves are 160-180 micrometers less than the thickness of the wafer; half angles are 11 degrees; the depths are 1400-1600 micrometers; the diamond sizes are 1000-2000#; the rotating speed of the coarse chamfering grinding wheel is 2500-5000rpm; machining is conducted for 1-2 rings; the rotating speed of the wafer is 16-20mm / s; the rotating speed of the fine chamfering grinding wheel is 3000-5000rmp; machining is conducted for 2-4 rings; and the rotating speed of the wafer is 10-15mm / s. The edge chamfering is conducted on the wafer by adopting the chamfering grinding wheel, so that the accuracy of an edge contour is high, the consistency of the edge quality is good, and the problem of a slip line due to the defect of the edge of the silicon wafer in a growth process of the thick-layer epitaxy is solved effectively.

Description

Technical field [0001] The invention relates to the processing of silicon single wafers, in particular to a chamfering grinding wheel and a chamfering method for processing silicon single wafers for thick epitaxy. Background technique [0002] In VDMOS, IGBT and other power electronic devices, silicon single wafers for thick epitaxy are often used as key raw materials. In the thick epitaxial growth of a silicon single wafer, the edge is particularly prone to "epitaxial crown" or slip line defects, which will have adverse effects on subsequent applications. [0003] The edge defects of thick epitaxy are mainly caused by the edge quality of silicon wafers. On the one hand, due to the crystal orientation, the edge of the silicon wafer has a higher deposition rate than the surface of the silicon wafer during epitaxial growth. If the surface of the silicon wafer edge is too small or the angle is too large, it is easy to form extrusion at the edge The stress, and this stress increases ...

AI Technical Summary

Problems solved by technology

However, the existing chamfering methods cannot meet the needs of silicon substrates for thick-layer epitaxial growth. There are local rough areas on the edge

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