PRODUCTION ENGINEERING MEASURE FOR IMPROVEMENT OF PRODUCTION TECHNIQUE TO INCREASE THE RELIABILITY FOR PNP INTERMEDIATE POWER SILICON PLANAR SWITCHING TRANSISTORS INCLUDING 2N3502

摘要

Effort was expended in investigating and evaluating temperature control problems which have caused surface pitting. Various techniques were used to study pitting in relation to temperature variations and other phenomena observed during processing. During the third quarter main emphasis was placed on process evaluation of the individual stations and the entire system. Minor changes were made. With the exception of Items 9 and 10, all of the objectives listed in the previous report were met. Three prototype jigs were completed and installed.nMask sets were delivered and feasibility runs were completed. Electrical data was taken and high temperature reverse bias life testing was begun. 250 hour HTRB data showed very good results with no failures on 300 devices. Repeat experimental runs were processed to confirm the results from the second quarter where the thermal gradient was found to be a major cause of Beta variation. Gas flow and diffusion coefficient change due to lattice stress were explored. Optimized runs were processed using manual photo resist operations. Runs using automatic masking line and the new photo resist jig were started.