| 摘要 |
A technique for enabling sufficient flow of flux cleaning fluids (230) and an underfill material (300) in the relatively low-profile gap (140) between a flip-chip bonded IC chip (1) and a substrate (10), such as a printed circuit board, is to provide at least one aperture (30) in the substrate under the IC chip. The use of such an aperture enables, for example, flux cleaning fluid to flow (240) through the aperture into the low-profile gap between the IC chip and the substrate surface, such as by the application of pressure or by gravity, which then exits through openings between formed interconnect bonds (110) at a sufficient flow rate to adequately remove flux residues. An epoxy underfill (300) to the IC chip can be formed in a similar manner. For example, a relatively thick bead of epoxy (400), such as on the order of the thickness of the IC chip (1), is deposited or stencil printed on the substrate surface (15) around the edges of the IC chip and capillary action is then relied upon to draw the epoxy into the low-profile gap (140). Undesirable air pockets which otherwise would develop form the displaced air as the epoxy flows into the low-profile gap can advantageously escape through the aperture (30) of the invention. <IMAGE> <IMAGE> |
