SEVENTY PERCENT OF THE FAILURES DETECTED DURING IN- CIRCUIT-TEST OF SURFACE MOUNT ASSEMBLIES IS CAUSED BY SOLDER DEFECTS. SOLDER DEFECTS THAT CAUSE FAILURE AT TEST ARE EITHER IN THE FORM OF A SHORT OR BRIDGE BETWEEN LEADS OF A DEVICE OR AN OPEN CIRCUIT DUE TO DEFICIENT SOLDER ATTACHMENT. AN ON-GOING PROCESS AUDIT CAN REDUCE MOST OF THE SOLDER DEFECTS BUT OFTEN, MANUFACTURING PROBLEMS ARE DESIGN RELATED. DESIGN AND PROCESS RECOMMENDATIONS ARE PRESENTED THAT WILL IMPROVE YIELDS AND IMPACT LONG-TERM RELIABILITY OF THE PRODUCT. AREAS OF DISCUSSION INCLUDE: LAND PATTERN GEOMETRY FOR FINE PITCH DEVICES; SOLDER PASTE MATERIALS AND STENCIL REQUIREMENTS; PROVIDING FOR AUTOMATED VISION ALIGNMENT SYSTEMS.
| Number of Pages : | 8 |
| Published : | 06/01/1991 |
