Self-coplanarity bumping shape for flip chip
US6940178B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 2002 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | Sep 21, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/351
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A stud bump structure for electrical interconnection between a pair of members includes a base portion, and a stem portion. The base portion is affixed to a pad or trace in one of the pair of members to be interconnected (such as an integrated circuit chip), and the stem end is configured to contact a metal pad on the other member (such as a printed circuit board) to complete the interconnect. According to the invention, the stem end is truncated to form a transverse plane, and the stem is more compliant than the base. Also, a method for forming a stud bump on a contact surface, includes forming a bump base portion on the surface, drawing out a generally conical tail from a top of the base, and truncating the tail to form a stem portion having a planar transverse top surface and having a length from the top of the base portion to the top surface. In some embodiments the tail portion, at least, of the stud bump is formed using a wire bonding tool. Also, a method for forming an interconnect between a first member and a second member of an electronic package includes providing one of the members with the stud bumps of the invention and then bringing the corresponding bumps and pads to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.