Automatic testing of metallized ceramic-polyimide (MCP) substrates

The automatic testing and handling of MCP substrates at IBM is discussed. After a brief description of the product and the manufacturing processes, the challenges of testing the product, the defect mechanisms, automatic product handling, the test electronics, computer control, and alternative ways to contact the part are discussed. Every substrate is electrically tested twice. It is tested once after all of the photolithographic and wet processes, but before pinning and tinning (midline test) and once before it is put to stock (end-of-line test). The handler and electronics of the end-of-line tester are discussed. The mid-line tester is in many ways similar to the end-of-line tester. The differences between mid-line and end-of-line testing are briefly outlined