ASSESSMENT OF PRESENT STATE-OF-THE-ART SAWING TECHNOLOGY OF LARGE DIAMETER INGOTS FOR SOLAR SHEET MATERNAL First Quarterly Report for Period Covering September 1—November 30, 1977

摘要

The objective of this program is to assess the present state-of-the-art sawing technology of large diameter silicon ingots (3" and 4" diameter) for solar sheet materials. During this period, work has progressed in three areas: (1) Slicing of the ingots with the multiblade slurry saw and the I.D. saw, (2) Characterization of the sliced wafers, and (3) Analysis of direct labor, expendable material costs, and wafer productivity.nMultiblade slurry slicing resulted in mechanical wafer yields of 95(%) for the 3" diameter ingot and 84 {%) for the 4" diameter ingot (using a 230 blade package to cut 6" ingot in length). A slicing test with the I.D. saw was performed to obtain mechanical yield versus both wafer thickness and cut rate, and the result showed a good yield (above 95%) down to 7-8 mils of wafer thickness for the 3" wafers and 11-12 mils for the 4" wafers if the cut rates were reduced to one (1) inch per minute.