Hybrid molds for molten solder screening process
US6390439B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1999 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Apr 7, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T156/10
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Hybrid molds for molding a multiplicity of solder balls for use in a molten solder screening process and methods for preparing such molds are disclosed. A method for forming the multiplicity of cavities in a pyramidal shape by anisotropically etching a crystalline silicon substrate along a specific crystallographic plane is utilized to form a crystalline silicon face plate used in the present invention hybrid mold. In a preferred embodiment, a silicon face plate is bonded to a borosilicate glass backing plate by adhesive means in a method that ensures coplanarity is achieved between the top surfaces of the silicon face plate and the glass backing plate. In an alternate embodiment, an additional glass frame is used for bonding a silicon face plate to a glass backing plate, again with ensured coplanarity between the top surfaces of the silicon face plate and the glass frame. In a second alternate embodiment, a silicon face plate is encased in an extender material which may be borosilicate glass or a polymer. The encasing is performed on a leveling fixture such that the top surface of the silicon face plate and the top surface of the extender material after solidification are perfectl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.