Process for recovering substrates
US5855735A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1995 |
| Grant date | Jan 5, 1999 |
| Priority date | — |
| Expiry date | Oct 3, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/30
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A process comprising removing surface layer materials from the wafer by inducing micro-fractures in the surface using a rotating pad and an abrasive slurry until all of the surface layer materials are removed; and chemically etching the surfaces of the wafer until all micro-fractures are removed therefrom. Edge materials are removed by abrasive tape. Wafer thickness reduction during recycling is less than 30 microns per cycle. One of the front and back surfaces of the wafer substrate is polished, any dots or grooves being on the non-polished side. The abrasive slurry contains more than 6 volume percent abrasive particles, and the abrasive slurry has a viscosity greater than about 2 cP at ambient temperature. The preferred pad comprises an organic polymer having a hardness greater than about 40 on the Shore D scale, optimally a polyurethane. The pressure of the pad against the wafer surface preferably does not exceed about 3 psi. Preferably, the chemical etching solution contains potassium hydroxide. An acidic solution can then be applied to the wafer surface. The reclaimed semiconductor wafer can be a silicon wafer having a matted side having etch pits which does not exceed 20 micr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.