METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20080233708A1
• Filed: 03/19/2008
• Published: 09/25/2008
• Est. Priority Date: 03/20/2007
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Hisamatsu, Hirokazu
• Application Number:
  US12/051,472
• Publication Number:
  US 20080233708A1
• Time in Patent Office: Days
• US Class Current: 438/410
• CPC Class Codes: H01L 21/76205 in a region being recessed from the surface, e.g. in a recess, groove, tub or trench region
• CPC Class Codes: H01L 29/66772 Monocristalline silicon transistors on insulating substrates, e.g. quartz substrates H01L29/66666 takes precedence; thin film FinFETs H01L29/66795

Abstract

A method for manufacturing a semiconductor device includes: forming a first semiconductor layer and a second semiconductor layer sequentially on a semiconductor substrate; forming a first groove penetrating the first semiconductor layer and the second semiconductor layer by partially etching the first semiconductor layer and the second semiconductor layer; forming a support covering the second semiconductor layer from inside of the first groove to a surface of the second semiconductor layer so as to support the second semiconductor layer; etching a sidewall formed in the first groove of the support so as to render the sidewall thin; forming a second groove exposing the first semiconductor layer by sequentially etching a part of the second semiconductor layer and a part of the first semiconductor layer; forming a cavity between the semiconductor substrate and the second semiconductor layer by etching the first semiconductor layer through the second groove under an etching condition in which the first semiconductor layer is more easily etched than the second semiconductor layer; and forming a buried oxide film by thermally oxidizing an upper surface of the semiconductor substrate and a lower surface of the second semiconductor layer that are facing inside of the cavity.

Claims

1. A method for manufacturing a semiconductor device, comprising:

forming a first semiconductor layer and a second semiconductor layer sequentially on a semiconductor substrate;

forming a first groove penetrating the first semiconductor layer and the second semiconductor layer by partially etching the first semiconductor layer and the second semiconductor layer;

forming a support covering the second semiconductor layer from inside of the first groove to a surface of the second semiconductor layer so as to support the second semiconductor layer;

etching a sidewall formed in the first groove of the support so as to render the sidewall thin;

forming a second groove exposing the first semiconductor layer by sequentially etching a part of the second semiconductor layer and a part of the first semiconductor layer;

forming a cavity between the semiconductor substrate and the second semiconductor layer by etching the first semiconductor layer through the second groove under an etching condition in which the first semiconductor layer is more easily etched than the second semiconductor layer; and

forming a buried oxide film by thermally oxidizing an upper surface of the semiconductor substrate and a lower surface of the second semiconductor layer that are facing inside of the cavity.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the etching the sidewall to render the sidewall thin includes forming a slit by partially etching the sidewall.

3. The method for manufacturing a semiconductor device according to claim 1 further comprising forming side surfaces of the second semiconductor and the first semiconductor that face the first groove of the second semiconductor layer and the first semiconductor layer to be in a continuous tapered shape in a sectional view so as to spread gradually wider from the second semiconductor layer to the first semiconductor layer before the support is formed.

4. The method for manufacturing a semiconductor device according to claim 2 further comprising filling the slit with an expansion member whose volume expands by thermal oxidation before the buried oxide film is formed.