Method for making circular tubular channels with two silicon wafers
US5575929A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1995 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Jun 5, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N30/6052
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A two-wafer microcapillary structure is fabricated by depositing boron nitride (BN) or silicon nitride (Si.sub.3 N.sub.4) on two separate silicon wafers (e.g., crystal-plane silicon with [100] or [110] crystal orientation). Photolithography is used with a photoresist to create exposed areas in the deposition for plasma etching. A slit entry through to the silicon is created along the path desired for the ultimate microcapillary. Acetone is used to remove the photoresist. An isotropic etch, e.g., such as HF/HNO.sub.3 /CH.sub.3 COOH, then erodes away the silicon through the trench opening in the deposition layer. A channel with a half-circular cross section is then formed in the silicon along the line of the trench in the deposition layer. Wet etching is then used to remove the deposition layer. The two silicon wafers are aligned and then bonded together face-to-face to complete the microcapillary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.