Injection molded solder process for forming solder bumps on substrates
US8820612B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2012 |
| Grant date | Sep 2, 2014 |
| Priority date | — |
| Expiry date | Jun 18, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/01322
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Solder bumps of uniform height are provided on a substrate through the use of injection molded solder. Copper pillars or ball limiting metallurgy are formed over I/O pads within the channels of a patterned layer of photoresist. Solder is injected over the pillars or BLM, filling the channels. The solder, which does not contain flux, is allowed to solidify. It forms a plurality of solder structures (bumps) of equal heights. Solder injection and solidification are preferably carried out in a nitrogen environment or a forming gas environment. Molten solder can be injected in channels formed in round wafers without spillage using a carrier assembly that accommodates such wafers and a fill head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.