Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

LGA Stencil Spec



LGA Stencil Spec | 3 August, 2000

Any opinion on what size aperture and stencil thickness is most optimum for Land Grid Array 1.27mm pitch with .6mm pad using SN/AG NC solder paste?

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Re: LGA Stencil Spec | 5 August, 2000

I'm confused ...

Land Grid Array (LGA). An alternative to the BGA for device manufacturers is to package their devices without any terminations on the bottom. Although not technically accurate, the easiest way to envision an LGA device is to picture a semiconductor with nothing but tiny round gold plated pads on the bottom. (If the device were a BGA, a BGA ball would be soldered to each pad.) (Another way to picture it is to think of a pin grid array with the pins cut from the package.) In order for LGA devices to get connected to a PCB, there must be some intermediary device with pins, or springs, or something, that can spring up and make contact with the little windows. So, almost by definition, a socket is required in order to connect an LGA device with its target PCB. Also, almost by definition, there must be some kind of cover or hold down mechanism that pushes the little windows of the device against the contacts of the intermediary connector.

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