Method for applying bonding agents to pad and/or interconnection sites in the manufacture of electrical circuits using a bonding agent injection head
US5478700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1993 |
| Grant date | Dec 26, 1995 |
| Priority date | — |
| Expiry date | Dec 21, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24917
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of applying bonding agents, such as solder pastes and conductive adhesives, to pad sites in the manufacture of electronic circuits uses a bonding agent injection head which includes a wiping guide, a blade which cooperates with the wiping guide to form an elongate nozzle slit, and an evacuation path ahead of the nozzle slit in a direction of movement of the injection head. A permanent mask with cavity openings is applied around conductive pads on a carrier. The conductive pads correspond to chip attachment sites. The injection head is brought into contact with a surface of the mask, and pressure is applied to a bonding agent in the injection head. The injection head is then moved over the surface of the mask, filling cavity openings with the bonding agent. The evacuation path ahead of the nozzle slit lets air out of the cavity openings as the cavity openings are filled with bonding agent. The injection head is then removed from the surface of the mask. If a solder paste is used, infrared radiation is applied to filled cavity openings to evaporate a paste flux and reflow solder to form solder balls within the cavity openings projecting above the mask. If a conductive adhesi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.