Method of planarizing a curved substrate and resulting structure
US6150255A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1999 |
| Grant date | Nov 21, 2000 |
| Priority date | — |
| Expiry date | Aug 13, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/4644
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
According to the present invention a technique for providing a planarized substrate with dendritic connections of solder balls, especially a multi-layer ceramic substrate is provided. In the case where the substrate has a raised central portion on the top surface on which are disposed top surface metallurgy pads, a layer of conformable photoimagable material is placed over the top surface. The photoimagable material is exposed and developed in a pattern corresponding to the pattern of the top surface metallurgy pads to form vias in the photoimagable material. Copper is plated in the vias in contact with the top surface metallurgy pads. The exposed surface of the photoimagable surface is then planarized, preferably by mechanical polishing to form a flat planar surface, with the ends of the vias exposed. Dendritic connector pads are then grown on the exposed ends of the vias to which solder ball connections of an I/C chip are releasably connected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.