Method of Enhancing Fatigue Life of Grid Arrays

Grid array devices are predominantly utilized in the electronics industry for connecting microprocessors and integrated circuits (ICs) to printed circuit boards. However, because of environmental and operational factors such as temperature fluctuations, the mechanical electrical connections between these devices often undergo significant stress, leading to decreased reliability and shortened lifespan. Current prevalent methodologies simply assume and accept these contractions and expansions as unavoidable phenomena and fail to mitigate their unfavorable impact. Over time, these contractions and expansions of columns during thermal cycling culminate in the degradation of grid array devices, often too early in their lifespan. This is further compounded by the shear stresses involved, which further decrease the life of these devices.

Technology Description

This method adds long-standing dependability to the mechanical electrical connection between a grid array device, such as a pin grid array (PGA) or column grid array (CGA), and a substrate like a printed circuit board (PCB). In this method, an intentional misalignment created between the PCB pads and columns is achieved by increasing the spacing pattern toward the periphery of the CGA leaving the columns to line up with the pads. As a consequence, there is a column tilt that escalates from the center toward the periphery of the CGA. What sets this technology apart is that it confronts and resolves the problem of contractions and expansions of columns during thermal cycling, which is a common challenge in such connections. By strategically introducing a tilt, the reduced column contraction and expansion increase the projected life of the grid array device. Furthermore, this method mitigates shear stress, boosting the projected life of the CGA significantly.