Alignment apparatus and method for mounting LSI and VLSI packages to a printed circuit board

An apparatus for aligning and mounting an LSI or VSLI integrated circuit (IC) chip to a printed circuit board, said LSI or VLSI chip being housed in a package having at least 64 leads protruding therefrom, said printed circuit board having respective pads to which said leads are to be bonded, said leads and said pads being accurately spaced with respect to each other, said apparatus comprising:

• lead alignment means for precisely aligning the leads of said chip with respect to a reference coordinate system of said apparatus at a first station thereof;
• pad alignment means for aligning the pads of said board with respect to said coordinate system at a second station of said apparatus;
• positioning/holding means for
• moving said leads and said pads, while still maintaining the desired alignments with said reference coordinate system to a third station of said apparatus,
• contacting each of said leads with a respective pad at said third station, and
• maintaining this contact until the leads of the chip may be bonded to their respective pads.

In a manufacturing assembly process wherein an integrated circuit (IC) package with a multiplicity of precisely placed leads must have said leads aligned with respect to a corresponding set of precisely placed pads on a printed circuit board prior to the bonding of said leads and where said leads are accurately fixed in position with respect to each other but are not accurately fixed with respect to said IC package, a process for aligning said leads with respect to said pads comprising the steps of:

• (a) performing a coarse alignment of said leads by aligning said package with respect to a known reference;
• (b) performing a fine alignment of said leads;
• with respect to said known reference;
• (c) holding and lifting said package so that said leads remain in said fine aligned position;
• (d) mounting said printed circuit board so that said pads are slidably aligned with said known reference;
• (e) sliding said printed circuit board underneath said package until said pads are below said leads;
• (f) lowering said package, while still maintaining the leads in the desired aligned position, until said leads contact said pads;
• (g) holding said leads against said pads;
• and
• (h) bonding said leads to said pads.