Semiconductor Device Having Solder-Free Gold Bump Contacts for Stability in Repeated Temperature Cycles

摘要

A semiconductor device has a chip (101) with gold studs (212) assembled on a tape substrate (102), which has solder balls (103) for attachment to external parts. The tape substrate (about 30 to 70 μm thick) has on its first surface first copper contact pads (221) covered with a continuous thin nickel layer (222) of about 0.04 to 0.12 μm thickness. Gold including stud (212) is contacting the nickel. On the second substrate surface are second copper contact pads (231) covered with an alloy layer (about 2 to 3 μm thick) including gold, copper/tin alloys, and copper/nickel/tin alloys; the alloys are metallurgically attached to the second copper pad and substantially free of unalloyed nickel. A reflow body (103) comprising tin is metallurgically attached to the alloy layer of each second pad.