Method of transferring solder balls onto a semiconductor device
US5219117A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 1, 1991 |
| Grant date | Jun 15, 1993 |
| Priority date | — |
| Expiry date | Nov 1, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/043
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Solder balls are transferred onto a semiconductor device (50), for example a flip chip semiconductor device, without using solder evaporation techniques. In one form, pre-formed solder balls (36) are placed in recesses (32) formed in a transfer substrate (30). A semiconductor die (12) having a plurality of bond pads (14) is positioned with respect to the transfer substrate so that the solder balls are aligned to, and in contact with, the bond pads. The solder balls are then reflowed to form a metallurgical bond to the bond pads. One embodiment of the invention utilizes a transfer substrate made of silicon so that the coefficient of thermal expansion of the transfer substrate will closely match that of the semiconductor die, thereby minimizing solder ball alignment variances. Use of silicon as a transfer substrate material also allows the recesses to easily be made non-wettable by conventional silicon oxidation techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.