Method for forming solder bumps of improved height and devices formed
US6179200A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1999 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | Feb 3, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/159
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for forming solder balls that have improved height on an electronic substrate such as a silicon wafer and devices formed are disclosed. In the method, after solder bumps are deposited by a conventional method such as evaporation, electroplating, electroless plating or solder paste screen printing, the solder bumps are reflown on the substrate in an upside down position such that the gravity of the solder material pulls down the solder ball and thereby increasing its height after the reflow process is completed. It has been found that a minimum of 5%, and preferably about 10% height increase has been achieved. Another benefit achieved by the present invention novel method which is associated with the increase in the solder ball height is a corresponding increase in the pitch distance between the solder balls by at least 5%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.