Abstract: A ball grid array (BGA) or chips scale package (CSP) integrated circuit (IC) (20) is manufactured by first identifying the most unreliable solder ball joints in the IC. These worst case joints, or joints in the vicinity of the worst case joints, are changed in pad dimension and exposed to more ball/bump conductive material than the other more robust joints (14) in the IC (20) to create a ball (24) on a larger pad (22) that is larger than the normal sized ball (14). The larger balls (24) are formed by placing multiple smaller balls (14) together on a single pad (22) to form one larger ball (24) during a reflow operation. The larger ball (24) improves the overall IC reliability by improving the reliability of the weakest joints in the IC design. In addition, the standoff of both the larger balls (24) and the smaller balls (14) are engineered to be substantially equal.

Abstract: A ball grid array (BGA) or chips scale package (CSP) integrated circuit (IC) (20) is manufactured by first identifying the most unreliable solder ball joints in the IC. These worst case joints, or joints in the vicinity of the worst case joints, are changed in pad dimension and exposed to more ball/bump conductive material than the other more robust joints (14) in the IC (20) to create a ball (24) on a larger pad (22) that is larger than the normal sized ball (14). The larger balls (24) are formed by placing multiple smaller balls (14) together on a single pad (22) to form one larger ball (24) during a reflow operation. The larger ball (24) improves the overall IC reliability by improving the reliability of the weakest joints in the IC design. In addition, the standoff of both the larger balls (24) and the smaller balls (14) are engineered to be substantially equal.

Abstract: A surface mountable flexible interconnect (100) for connecting two electronic subassemblies is constructed from a flexible film substrate (110). Conductive metal runners (120) run along the bottom surface (114) of the substrate and connect an array of solder pads (122), each having an attached solder bump (123), to a second terminal portion (124) located at the second end of the substrate. A rigid sheet of printed circuit board material (130), attached to the top surface of the substrate using a strong adhesive (142), lies directly above the array of solder pads and acts as stress relief mechanism. A slightly tacky temporary adhesive (140) is used to attach the second end of the substrate to the topside (132) of the rigid sheet.

Abstract: A surface mountable flexible interconnect (10) for connecting two circuit board (30, 32) consists of a flex circuit (12) with solderable runners (14) on one side, the runners traversing the flex circuit from one end to the other. There is a solderable pad (16) at the end of each runner, and each solderable pad has a solder bump (18) fused to it. A rigid carrier ring (20) is used to hold the flex circuit in position prior to placement on the PCB. The flex circuit is formed into a U-shaped loop (26), and the loop is aligned to the carrier so that the loop is situated in an aperture (24) in the carrier. The solder pads lie directly under the carrier ring and face away from it. An adhesive (22) bonds the flex circuit to the carrier ring.