Elastic foamed sheet and wafer-polishing jig using the sheet
US5538465A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 1995 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | Jan 6, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249979
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An elastic foamed sheet is disclosed which is usable as waxless polishing backing pads for wafers and capable of producing mirror polish wafers excelling in flatness. This elastic foamed sheet possesses at least a foamed layer 2 and is characterized by the fact that a plurality of bubbles 4 in the foamed layer 2 meet the following conditions: (1) that the bubbles are slender discrete bubbles erected parallelly to one another and dispersed at a substantially equal pitch in the direction of width of the foamed layer 2 and the bubbles 4 are substantially equal in size, shape, and position of formation in the direction of thickness of the foamed layer 2, (2) that center lines of the bubbles 4 in the direction of length thereof are parallel to the direction of thickness of the foamed layer 2, and (3) that the diameters of the bubbles 4 are minimized in the terminal part of the foamed layer 2 on one surface side thereof and gradually increased in the direction from the one surface side to the other surface side of foamed layer 2 until the bubbles form openings 6 thereof in the surface of the foamed layer 2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.