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Method for a bending-shock test procedure with an angled BGA layout on a test coupon

IP.com Disclosure Number: IPCOM000007120D
Publication Date: 2002-Feb-26
Document File: 4 page(s) / 117K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a bending-shock test procedure with an angled BGA layout on a test coupon. Benefits include improved circuit board design, improved testing, and improved FEA modeling.

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Method for a bending-shock test procedure with an angled BGA layout on a test coupon

Disclosed is a method for a bending-shock test procedure with an angled BGA layout on a test coupon. Benefits include improved circuit board design, improved testing, and improved FEA modeling.

Description


             
The disclosed method calculates the dynamic failure strength of the corner solder joint of the corner ball through the finite element analysis (FEA) and applies dynamic failure criterion to the design of a ball grid array (BGA), heatsink, and other enabling parts on a PCB.

              The proposed test setup includes a 4-point bending shock test (see Figure 1) but may include a 3-point or other bending (see Figure 2) test. The 4-point bending test reduces the sensitivity of the package location on the test coupon.

              The disclosed test board design is an 8-inch by 4-inch PCB (not limited to that size) and a rectangular BGA (not limited to that shape) mounted at the center of the PCB with its long diagonal parallel to the PCB long edge (see Figure 3b). For a square BGA, its edge is rotated 45 degrees with respect to the PCB edges (see Figure 4). This setup ensures that the first solder joint failure occurs at the corner of the BGA.

              Accelerometer, strain gage, LVDT and other sensors are mounted at various locations to monitor displacement, strain, strain rate, and acceleration during the shock test. The fracture of the solder joint is monitored by the daisy-chain continuity and, possibly, any significant s...