Semiconductor physical-quantity sensor and method for manufacturing same
First Claim
1. A method for manufacturing a semiconductor physical-quantity sensor comprising a semiconductor substrate and a movable portion of a beam structure composed of a thin film, the method comprising the steps of:
- forming an underlying film having an irregularities portion on a flat surface of the semiconductor substrate in a region between the semiconductor substrate and a movable portion location;
forming a sacrificial layer on the underlying film;
forming a movable portion thin film on the sacrificial layer; and
removing the sacrificial layer beneath the movable portion thin film by etching to thereby form a movable portion of the beam structure.
2 Assignments
0 Petitions
Accused Products
Abstract
A polysilicon thin film is formed on a silicon substrate by LPCVD technique. At this time, by a performing film formation at a low temperature of approximately 620° C., for example, an irregularities portion is formed on the surface thereof. A silicon oxide film that serves as a sacrificial layer is formed thereon and, on this sacrificial layer, a polysilicon thin film that serves as a movable portion forming thin film is formed. Then, the silicon oxide film beneath this polysilicon thin film is removed by wet etching to thereby form a movable portion. As a result, the movable portion of a beam structure that is composed of the thin film is disposed over the silicon substrate at a prescribed distance therefrom. Although an etchant-replacing liquid enters between the movable portion and the substrate whereby the movable portion is attracted toward the substrate, the movable portion is prevented from adhering to the substrate by means of the irregularities portion.
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Citations
40 Claims
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1. A method for manufacturing a semiconductor physical-quantity sensor comprising a semiconductor substrate and a movable portion of a beam structure composed of a thin film, the method comprising the steps of:
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forming an underlying film having an irregularities portion on a flat surface of the semiconductor substrate in a region between the semiconductor substrate and a movable portion location; forming a sacrificial layer on the underlying film; forming a movable portion thin film on the sacrificial layer; and removing the sacrificial layer beneath the movable portion thin film by etching to thereby form a movable portion of the beam structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing a semiconductor physical-quantity sensor comprising a semiconductor substrate and a movable portion of a beam structure composed of a thin film, the method comprising the steps of:
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forming a sacrificial layer having a surface irregularities portion on a surface of the semiconductor substrate in a region between the semiconductor substrate and a movable portion location; forming a movable portion thin film on the sacrificial layer; and removing the sacrificial layer beneath the movable portion thin film by etching to thereby form a movable portion of the beam structure whose underside has an irregularities portion formed by the surface irregularities portion of the sacrificial layer. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for manufacturing a semiconductor physical-quantity sensor comprising a semiconductor substrate and a movable portion of a beam structure composed of a thin film, the method comprising the steps of:
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forming an underlying film having an irregularities portion on a surface of the semiconductor substrate in a region between the semiconductor substrate and a movable portion region; forming, on the underlying film, a sacrificial layer having a surface irregularities portion that corresponds to a part of the irregularities portion of the underlying layer; forming a movable portion thin film on the sacrificial layer; and removing the sacrificial layer beneath the movable portion thin film by etching to thereby form the movable portion of the beam structure, the movable portion including an irregularities portion on an underside thereof formed by the surface irregularities portion of the sacrificial layer. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A semiconductor physical-quantity sensor comprising:
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a semiconductor substrate; a movable portion of a beam structure that is composed of a thin film and disposed over the semiconductor substrate with a cavity interposed therebetween and is displaceable in accordance with an action of a physical quantity; and an underlying film that has an irregularities surface and has conductivity and that is disposed on a surface of the semiconductor substrate in a region between the semiconductor substrate and the movable portion, wherein the underlying film is electrically connected to the movable portion. - View Dependent Claims (28, 29, 30, 31)
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32. A method of manufacturing a semiconductor physical-quantity sensor on a semiconductor substrate, comprising:
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depositing on the substrate a surface film that includes an irregular surface region; depositing a sacrificial layer on the surface film; depositing a movable sensor component film on the sacrificial layer; and removing the sacrificial layer beneath the movable sensor component film, by etching, to form a movable sensor component over the irregular surface region of the surface film. - View Dependent Claims (33, 34, 35, 36, 37)
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38. A semiconductor physical-quantity sensor comprising:
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a semiconductor substrate; a movable portion of a beam structure that is composed of a thin film and that is disposed over the semiconductor substrate with a cavity interposed therebetween, and is displaceable in accordance with an action of a physical quantity, the movable portion having an underside with an irregularities surface that opposes the semiconductor substrate; and an underlying film that has conductivity and that is disposed on a surface of the semiconductor substrate in a region between the semiconductor substrate and the movable portion, wherein the underlying film is electrically connected to the movable portion. - View Dependent Claims (39, 40)
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Specification