Method of manufacturing semiconductor device capable of sensing dynamic quantity

• US 6,753,201 B2
• Filed: 05/28/2002
• Issued: 06/22/2004
• Est. Priority Date: 05/28/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kano, Kazuhiko, Sakai, Minekazu, Fukada, Tsuyoshi, Muto, Hiroshi, Ao, Kenichi, Takeuchi, Yukihiro, Oohara, Junji
• Primary Examiner(s): GHYKA, ALEXANDER G
• Application Number:
  US10/154,784
• Publication Number:
  US 20020177252A1
• Time in Patent Office: 756 Days
• Field of Search: 438/48, 438/22, 438/24, 438/50, 438/51, 438/52, 438/53, 438/739, 438/710, 438/714, 438/731
• US Class Current: 438/48
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81C 1/0019 Flexible or deformable structures not provided for in groups B81C1/00142 - B81C1/00182
• CPC Class Codes: B81C 1/00531 Dry etching
• CPC Class Codes: B81C 1/00936 Releasing the movable structure without liquid etchant
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: H01L 21/76232 of trenches having a shape other than rectangular or V-shape, e.g. rounded corners, oblique or rounded trench walls H01L21/76229 takes precedence
• CPC Class Codes: H01L 21/76264 SOI together with lateral isolation, e.g. using local oxidation of silicon, or dielectric or polycristalline material refilled trench or air gap isolation regions, e.g. completely isolated semiconductor islands
• CPC Class Codes: H01L 21/76283 Lateral isolation by refilling of trenches with dielectric material

Abstract

A method of manufacturing a semiconductor device is provided. The device is manufactured with use of an SOI (Silicon On Insulator) substrate having a first silicon layer, an oxide layer, and a second silicon layer laminated in this order. After forming a trench reaching the oxide layer from the second silicon layer, dry etching is performed, thus allowing the oxide layer located at the trench bottom to be charged at first. This charging forces etching ions to impinge upon part of the second silicon layer located laterally to the trench bottom. Such part is removed, forming a movable section. For example, ions to neutralize the electric charges are administered into the trench, so that the electric charges are removed from charged movable electrodes and their charged surrounding regions. Removing the electric charges prevents the movable section to stick to its surrounding portions.

Claims

1. A method of manufacturing a semiconductor device having a semiconductor substrate in which an insulation layer is layered on a first semiconductor layer and a second semiconductor layer is layered on the insulation layer, and a movable section formed in the second semiconductor layer and displaceable in response to a dynamic quantity to be applied, the method comprising:

preparing the semiconductor substrate;

forming a trench to demarcate the movable section within the prepared semiconductor substrate so that the trench reaches the insulation layer from a surface of the second semiconductor layer; and

forming the movable section by performing dry etching on the trench-formed semiconductor substrate to remove the laterally located part of the second semiconductor layer,

wherein the forming of the movable section includes;

charging the insulation layer located at a bottom of the trench during the performing of the dry etching to force etching ions to impinge onto part of the second semiconductor layer located laterally to the bottom of the trench,

removing electric charges caused due to the charging of the insulation layer from at least one of the movable section, a region of the second semiconductor layer that faces the movable section, and a region of the insulation layer that faces the movable section, and

alternately repeating the charging of the insulation layer and the removing of electric charges before the movable section is completely formed.

2. The manufacturing method of claim 1, wherein the electric charges are removed by intermittently performing the dry etching during the movable-section forming.

3. The manufacturing method of claim 2, wherein the electric charges are removed by providing the electric charges with ions to neutralize the electric charges during each of the intermittent periods of time with no dry etching.

4. The manufacturing method of claim 1, wherein the electric charges are removed by leaving the movable-section-formed semiconductor substrate during a period of time determined so that the electric charges disappear, after the movable-section forming.

5. The manufacturing method of claim 1, wherein the electric charges are removed by providing the electric charges with ions to neutralize the electric charges after the movable-section forming.

6. The manufacturing method of claim 1, wherein the electric charges are removed, during the trench forming, by placing an electrically conductive member on either of a region, which provides at least the movable section, of a surface of the second semiconductor layer or a region, which provides a partial region facing the movable section, of the second semiconductor layer.

7. The manufacturing method of claim 6, wherein the conductive member is used in common with a mask member for forming the trench.

8. A method of manufacturing a semiconductor device having a semiconductor substrate in which an insulation layer is layered on a first semiconductor layer and a second semiconductor layer is layered on the insulation layer, and a movable section formed in the second semiconductor layer and displaceable in response to a dynamic quantity to be applied, the method comprising:

preparing the semiconductor substrate;

forming a trench to demarcate the movable section within the prepared semiconductor substrate so that the trench reaches the insulation layer from a surface of the second semiconductor layer;

forming the movable section by performing dry etching on the trench-formed semiconductor substrate, during which the dry etching the insulation layer located at a bottom of the trench is charged to force etching ions of the dry etching to impinge onto part of the second semiconductor layer located laterally to the bottom of the trench, thus the laterally located part of the second semiconductor layer being removed; and

cleaning a region, of the movable section that faces the insulation layer during a vapor phase in which oxygen ions serve as the etching ions without using a liquid phase containing the etching ions.