Process for forming solder balls on a plate having apertures using solder paste and transferring the solder balls to semiconductor device
US5643831A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1995 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Oct 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/1476
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for fabricating a semiconductor device using a solder ball forming plate having cavities. The plate is made from a silicon plate having a flat surface in a <110> crystallographic plane, and an orientation flat in a <1-11> crystallographic plane. The cavities are formed on the flat surface of the plate by etching, using a mask having openings in the shape of rhombus arranged such that one side of the rhombus is generally parallel to the <1-11> crystallographic plane. As a result, the cavities having wedge-shaped bottom are formed. The cavities are then filled with a solder paste and are heated to form solder balls in the cavities while the plate in an inclined position. The solder balls are then transferred from the plate to a semiconductor chip.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.