Unlocking the Mystery of Circuit Board Failures A Case Study Presented By: Alaa Arif EDTC 560 January 15, 2007

Terms & Definitions Board: Printed Circuit Board (PCB). ESD: Electro-Static Discharge. It is the release of a build up of charge, similar to the shock some people experience when touching a metal surface or another person.

Terms & Definitions FPY: First Pass Yield. The percentage of boards that pass the test during the first trial. NDF: No Defect Found failure. Failure without any apparent cause.

Problem Statement Boards Failures: For the first time in the companys history, a newly released product failed to reach FPY goals. Quantity of boards failures exceeded all expectations.

Analysis Analysis revealed that 2 types of failures are mainly responsible for the low FPY: ESD Failures NDF Failures

Analysis - ESD ESD Failures: Caused by unsafe ESD practices. ESD could damage sensitive components on the PCB. Increased over the first 3 months.

Analysis - ESD ESD Failures: Caused by unsafe ESD practices. ESD could damage sensitive components on the PCB. Increased over the first 3 months.

Analysis - ESD ESD Failures: Caused by unsafe ESD practices. ESD could damage sensitive components on the PCB. Increased over the first 3 months.

Analysis - NDF NDF Failures: Caused by operator error. Malfunction of test equipment. Decreased over the first 3 months.

Analysis - NDF NDF Failures: Caused by operator error. Malfunction of test equipment. Decreased over the first 3 months.

Analysis - NDF NDF Failures: Caused by operator error. Malfunction of test equipment. Decreased over the first 3 months.

Solution - ESD Addressing ESD Failures at each level: Work station. Operators.

Solution - ESD Work Station: Properly ground the work station. Coat floor with ESD-safe material. Cover workbench with ESD-safe mat.

Solution - ESD Operator: Wears ESD-safe smock. Uses ESD-safe wrist strap. Cover shoes with ESD-safe heel straps.

Solution - NDF Addressing NDF at each level: Test Equipment. Operator. Procedures.

Solution - NDF Test Equipment: Train maintenance technicians. Increase frequency of preventive maintenance. Provide ample quantity of spare parts.

Solution - NDF Operator: Share with operators the test results. Explain the consequences of the excessive amount of boards failures. Train and re-train operators.

Solution - NDF Procedures: Document test procedure. Add illustrations to test procedures. Make test documents easily accessible.

Results December test data showed improvement: Trend line

End of the Presentation!