Clocked burn-in of thick-film integrated circuits - heating cassette by hot-air blowers in different temp. zones sepd. by moving hollow partitions

摘要

The method involves treating ceramic substrates in a "pusher oven" in specially shaped cassettes in which 30 to 50 substrates are spaced about 5 millimetres apart between thickened and stiffened end plates. Hot-air blowers are used for different temp. ranges with one cassette at a time in each temp. zone as the workload is moved through the oven in stages of about 2 minutes each with fresh air control by a Carbon-monoxide sensor. ADVANTAGE - More than 3000 substrates per hour can be treated in oven about 3 metres long. Better temp. distribution and stability. Several single steps missed out by use of cassettes.