Moly mask construction and process
US7115207B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 2003 |
| Grant date | Oct 3, 2006 |
| Priority date | — |
| Expiry date | Mar 3, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/14
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method of manufacturing a metal mask for an integrated circuit chip interconnect solder bump. The invention deposits a very thick photoresist on both sides of a very thick molybdenum foil sheet (the molybdenum sheet is at least 8 mils thick and the photoresist is at least 5 microns thick). Then the process exposes and develops the photoresist to produce at least one opening having a diameter of at least 5 mil. The invention simultaneously etches both sides of the molybdenum foil using a very low etchant spray pressure of approximately 5 psi to form at least one via in the molybdenum foil that has a diameter of at least 12 mil and a knife-edge of 0.2 mil. The photoresist is removed after the etching process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.