Method and apparatus for filling high density vias
US4954313A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 3, 1989 |
| Grant date | Sep 4, 1990 |
| Priority date | — |
| Expiry date | Feb 3, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/082
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for providing void-free low-electrical-resistance conductive cores in vias having an aspect ratio of greater than approximately 6 includes the steps of providing a conductive thixotropic paste on the top surface of a substrate having vias provided therein, applying pressure to the paste and concurrently applying pressure to the paste and bottom surface of the substrate to force the thixotropic paste into the vias. Vibratory motion may also be applied to the substrate and paste concurrently with the application of pressure and vacuum. The paste is then dried in a vacuum, and subsequently sintered in a two-step process including a slow ramp up to temperature to allow the paste to outgas followed by a high temperature treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.