Method of manufacturing dynamic amount semiconductor sensor

• US 6,048,774 A
• Filed: 06/25/1998
• Issued: 04/11/2000
• Est. Priority Date: 06/26/1997
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kano, Kazuhiko, Kato, Nobuyuki, Sugiura, Makiko, Yamamoto, Toshimasa
• Primary Examiner(s): Chaudhari, Chandra
• Assistant Examiner(s): BLUM, DAVID S
• Application Number:
  US09/103,935
• Time in Patent Office: 656 Days
• Field of Search: 438/406, 438/411, 257/417, 73/514.35
• US Class Current: 438/406
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

In a method of manufacturing a dynamic amount sensor including a beam structure and a fixed electrode which are respectively supported by anchor parts of a substrate, opening portions are formed on a first semiconductor substrate where the anchor parts are to be formed. Each of the opening portions is composed of a plurality of stripe-like openings. Then a first thin film for forming the anchor parts and a second thin film are formed on the first semiconductor substrate in that order. After the surface of the second thin film is polished, a second semiconductor substrate is bonded to the polished surface of the second thin film. In this method, because the opening portions are composed of the plurality of stripe-like openings, the second thin film is flattened without having any steps thereon.

Claims

1. A method of manufacturing a dynamic amount semiconductor sensor comprising a support substrate having first and second anchor parts protruding from a surface thereof, a beam structure supported by the first anchor part and having a movable electrode displaceable by a dynamic amount, and a fixed electrode supported by the second anchor part to face the movable electrode, the method comprising steps of:

forming a sacrificial layer on a first semiconductor substrate, the first semiconductor substrate being for forming the beam structure and the fixed electrode;

forming an insulating layer on the sacrificial layer;

forming first and second opening portions in the insulating layer and in the sacrificial layer where the first and second anchor parts are to be formed, at least one of the first and second opening portions being composed of a plurality of openings;

forming a first thin film on the insulating layer, the first thin film being for forming the first and second anchor parts;

forming a second thin film on the first thin film;

flattening a surface of the second thin film on an opposite side of the first thin film;

bonding the first semiconductor substrate and a second semiconductor substrate for serving as the support substrate with the second thin film interposed therebetween; and

removing the sacrificial layer.

2. The method of claim 1, wherein the plurality of openings have stripe-like shapes with widths equal to one another.

3. The method of claim 1, wherein the second thin film is made of polycrystalline silicon.

4. The method of claim 1, wherein:

the fixed electrode has a pole-like part fixed to the support substrate via a third anchor part;

in the step of forming the first and second opening portions, a third opening portion including a stripe-like opening is formed in the insulating layer and in the sacrificial layer where the third anchor part is to be formed; and

the plurality of openings of the one of the first and second opening portions have stripe-like shapes with widths equal to one another and equal to that of the stripe-like opening of the third opening portion.

5. The method of claim 1, wherein:

in the step of forming the first and second opening portions, an electrode terminal opening portion is formed in the insulating layer and in the sacrificial layer for forming an electrode terminal anchor part, the electrode terminal anchor part being for fixing thereon an electrode terminal part electrically connected to the fixed electrode, the electrode terminal opening portion being composed of a plurality of openings.

6. The method of claim 1, further comprising steps of:

forming an alignment groove in a first semiconductor substrate before the step of forming the sacrificial layer; and

polishing a surface of the first semiconductor substrate on an opposite side of the second semiconductor substrate to expose the alignment groove after the step of bonding the first and second semiconductor substrates.

7. The method of claim 6, wherein the alignment groove is filled with the sacrificial layer in the step of forming the sacrificial layer.

8. The method of claim 6, wherein the alignment groove is filled with a material having a polishing rate approximately equal to that of the first semiconductor substrate before the step of forming the sacrificial layer.

9. The method of claim 8, wherein the first semiconductor substrate is made of single crystal silicon, and the material for filling the alignment groove is polycrystalline silicon.

10. A method of manufacturing a dynamic amount semiconductor sensor comprising a support substrate having first and second anchor parts protruding from a surface thereof, a beam structure supported by the first anchor part and having a movable electrode displaceable by a dynamic amount, and a fixed electrode supported by the second anchor part to face the movable electrode, the method comprising steps of:

forming a sacrificial layer on a first semiconductor substrate, the first semiconductor substrate being for forming the beam structure and the fixed electrode;

forming an insulating layer on the sacrificial layer;

forming first and second opening portions in the insulating layer and in the sacrificial layer where the first and second anchor parts are to be formed;

forming a first thin film on the insulating layer, the first thin film being for forming the first and second anchor parts;

forming a second thin film on the first thin film;

flattening a surface of the second thin film on an opposite side of the first thin film;

bonding the first semiconductor substrate and a second semiconductor substrate for serving as the support substrate with the second thin film interposed therebetween;

forming a plurality of grooves in the first semiconductor substrate for defining the beam structure and the fixed electrode in the first semiconductor substrate; and

removing the sacrificial layer by etching through the plurality of grooves to provide the beam structure and the fixed electrode on the second semiconductor substrate.

11. The method of claim 10, further comprising a step of forming an electrode on the first semiconductor substrate on an opposite side of the second semiconductor substrate before the step of forming the plurality of grooves.

12. The method of claim 10, further comprising a step of forming an alignment mark on the first semiconductor substrate before the step of forming the sacrificial layer, the alignment mark being for defining positions of the plurality of grooves on the first semiconductor substrate.

13. The method of claim 12, wherein:

the alignment mark is an alignment groove formed in the first semiconductor substrate; and

the alignment groove is filled with the sacrificial layer to serve as the alignment mark when the sacrificial layer is formed on the first semiconductor substrate.

14. The method of claim 12, wherein:

the alignment mark is an alignment groove formed in the first semiconductor substrate;

the alignment groove is filled with a material having a polishing rate approximately equal to that of the first semiconductor substrate; and

the sacrificial layer is formed on the first semiconductor substrate to cover the alignment groove filled with the material.

15. The method of claim 14, wherein the first semiconductor substrate is made of single crystal silicon, and the material for filling the alignment groove is polycrystalline silicon.

16. The method of claim 12, further comprising a step of polishing the first semiconductor substrate on the opposite side of the second semiconductor substrate to expose the alignment groove after the step of bonding the first and second semiconductor substrates,

wherein an end of the step of polishing the first semiconductor substrate is detected by the exposure of the alignment groove.

17. A method of manufacturing a dynamic amount semiconductor sensor comprising a support substrate having first and second anchor parts protruding from a surface thereof, a beam structure supported by the first anchor part and having a movable electrode displaceable by a dynamic amount, and a fixed electrode supported by the second anchor part to face the movable electrode, the method comprising steps of:

forming a sacrificial layer on a first semiconductor substrate, the first semiconductor substrate being for forming the beam structure and the fixed electrode;

forming an insulating layer on the sacrificial layer;

forming first and second opening portions in the insulating layer and in the sacrificial layer where the first and second anchor parts are to be formed, at least one of the first and second opening portions being composed of a plurality of openings;

forming a first thin film on the insulating layer, the first thin film being for forming the first and second anchor parts;

forming a second thin film on the first thin film;

flattening a surface of the second thin film on an opposite side of the first thin film;

bonding the first semiconductor substrate and a second semiconductor substrate for serving as the support substrate with the second thin film interposed therebetween;

forming a plurality of grooves in the first semiconductor substrate for defining the beam structure and the fixed electrode in the first semiconductor substrate; and

removing the sacrificial layer by etching through the plurality of grooves to provide the beam structures and the fixed electrode on the second semiconductor substrate.

18. The method of claim 17, wherein the first and second opening portions are formed to respectively have a first plurality of openings and a second plurality of openings.

19. The method of claim 17, wherein:

the fixed electrode has a pole-like part fixed to the support substrate via a third anchor part;

in the step of forming the first and second opening portions, a third opening portion including a stripe-like opening is formed in the insulating layer and in the sacrificial layer where the third anchor part is to be formed; and

the plurality of openings of the one of the first and second opening portions have stripe-like shapes with widths equal to one another and equal to that of the stripe-like opening of the third opening portion.

20. The method of claim 17, wherein:

in the step of forming the first and second opening portions, an electrode terminal opening portion is formed in the insulating layer and in the sacrificial layer for forming an electrode terminal anchor part, the electrode terminal anchor part being for fixing thereon an electrode terminal part electrically connected to the fixed electrode, the electrode terminal opening portion being composed of a plurality of openings.

21. The method of claim 17, further comprising steps of:

forming an alignment groove in a first semiconductor substrate to be filled with the sacrificial layer in the step of forming the sacrificial layer; and

polishing a surface of the first semiconductor substrate on an opposite side of the second semiconductor substrate to expose the sacrificial layer in the alignment groove after the step of bonding the first and second semiconductor substrates.

22. The method of claim 17, further comprising a step of forming an alignment mark on the first semiconductor substrate before the step of forming the sacrificial layer, the alignment mark being for defining positions of the plurality of grooves on the first semiconductor substrate.

23. The method of claim 22, wherein:

the alignment mark is an alignment groove formed in the first semiconductor substrate; and

the alignment groove is filled with the sacrificial layer when the sacrificial layer is formed on the first semiconductor substrate.

24. The method of claim 23, further comprising a step of flattening the first semiconductor substrate on an opposite side of the second semiconductor substrate after bonding the first and second semiconductor substrates,

wherein the step of flattening the first semiconductor substrate is stopped when the sacrificial layer in the alignment groove is exposed.