Method for controlling solder bump height and volume for substrates containing both pad-on and pad-off via contacts
US5660321A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1996 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Mar 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/043
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An method for depositing solder onto the pad-on and pad-off via contacts of a substrate is disclosed. In one embodiment the present invention includes positioning a mask having a first opening of a first diameter and a second opening of a second diameter over a substrate having both pad-on and pad-off via contacts. The substrate is positioned over the substrate such that the first opening is positioned over the pad-on via contact and the second opening is positioned over the pad-off via contact. Solder of a first volume and solder of a second volume are deposited onto the pad-on and pad-off via contacts, respectively, by forcing a solder paste through the mask openings. In this manner, solder bumps having a uniform height and volume above the pad-on via contact plane is established after reflowing the deposited solder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.