Wafer scale oblique angle plasma etching
| DWPI Title: Clamping fixture arrangement for performing semiconductor wafer scale angled plasma etching, has faraday cage including grid-covered angled surface such that reactive ions utilized for plasma etching pass through angled surface |
| Abstract: Wafer scale oblique angle etching of a semiconductor substrate is performed in a conventional plasma etch chamber by using a fixture that supports a multiple number of separate Faraday cages. Each cage is formed to include an angled grid surface and is positioned such that it will be positioned over a separate one of the die locations on the wafer surface when the fixture is placed over the wafer. The presence of the Faraday cages influences the local electric field surrounding each wafer die, re-shaping the local field to be disposed in alignment with the angled grid surface. The re-shaped plasma causes the reactive ions to follow a linear trajectory through the plasma sheath and angled grid surface, ultimately impinging the wafer surface at an angle. The selected geometry of the Faraday cage angled grid surface thus determines the angle at with the reactive ions will impinge the wafer. |
| Use: Clamping fixture arrangement for performing semiconductor wafer scale angled plasma etching for fabrication of three-dimensional integrated circuits. |
| Advantage: The arrangement provides wafer scale oblique angle etching to allow creation of three-dimensional structures in a high volume manufacturing environment. |
| Novelty: The arrangement (10) has a set of individual Faraday cages (12, 12ij) placed over and attached to a conductive support plate (14) in a pattern that corresponds to die locations on a semiconductor wafer to be etched. Each Faraday cage includes a grid-covered angled surface (16) such that reactive ions utilized for plasma etching pass through the grid-covered angled surface at an orientation normal to the angled surface and impinge a wafer surface. The conductive support plate includes a recessed underside area to accommodate and cover the wafer during oblique angle etching process. |
| Filed: 9/17/2014 |
| Application Number: US14489362A |
| Tech ID: SD 13113.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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