Method to improve reliability for flip-chip device for limiting pad design
US6602775B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 2001 |
| Grant date | Aug 5, 2003 |
| Priority date | — |
| Expiry date | Aug 16, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/14
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of fabricating a solder bump including the following steps. A UBM over a substrate.having an exposed pad portion is provided. The UBM being in electrical contact with the pad portion. A first patterning layer is formed over the UBM. The first patterning layer including a photosensitive material sensitive to light having a first wavelength. A second patterning layer is formed over the first patterning layer. The second patterning layer including a photosensitive material sensitive to light having a second wavelength. The first patterning layer is selectively exposed with the light having the first wavelength, leaving a first unexposed portion substantially centered over the pad portion between first exposed portions. The second patterning layer is selectively exposed with the light having the second wavelength, leaving a second unexposed portion wider than, and substantially centered over, the first unexposed portion of the exposed first patterning layer. The second unexposed portion of the exposed second patterning layer being between exposed portions. The second unexposed portion of the exposed second patterning layer and the first unexposed portion of the exposed first p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.