Authored By:
Marti McCurdy
Silicon Turnkey Solutions
Milpitas, CA, USA
Isabel de Sousa, Robert Martel and Alain Lessard
IBM Canada
Bromont, QC, Canada
Summary
The Column Grid Array (CGA) module is a high reliability JEDEC format package, with several options adaptable to nd user needs. The dark or white ceramic thickness ranging from 1.4mm to 4.2mm and body sizes up to 52.5 mm JEDEC. The typical 42.5 mm CGA module is configured with a full array of 1089 I/O (33x33) with 1.27mm (0.050") pitch or 1657 I/O (41x41) with 1.00mm (0.040") pitch of 10/90 ( Sn/PB) columns and eutectic alloy solder connections The CGA shows superior coplanarity and reliability compared to a BGA device and can be utilized on a JEDEC register package, bare chips, or capped modules with thermal management to include wire bond or Flip Chip C4 devices.
Substrate and System Level Reliability (SLR) is enhanced by a greater stand-off, flexible interconnection, improved thermal characterization, and improved thermal fatigue life of package solder joint. The contact integrity is where the Column Attach technology takes the lead over other Ball Grid predecessors. The need for complex, high density interconnects that can handle contact resistance, fatigue, CTE compliance, and ultra-high speed connectivity makes the process so valuable. The CGA has a proven long shelf life and maintains wetting properties with proper board placement as well.
Conclusions
The CGA remains the superior interconnect for thermal management and reliable interconnect for high complexity devices used in high reliability applications. The IBM patented materials and processes that includes process control, accuracy, and precision of the CGA flow, offers the strongest and most reliable column attach process in the market place. Testing of the LGA and CGA provides the assurance of proper column attach and wetting, to ensure the device will operate at speed across specific temperature ranges and meet requirements per the data sheet. The reliability data supports that CGA remains a viable solution for the high reliability market place.
Initially Published in the SMTA Proceedings
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