Method for manufacturing a micromechanical component and a component that is manufactured in accordance with the method

• US 6,951,824 B2
• Filed: 12/28/2000
• Issued: 10/04/2005
• Est. Priority Date: 02/10/2000
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Fischer, Frank, Graf, Eckhard, Hein, Peter
• Primary Examiner(s): Pham, Hoai
• Assistant Examiner(s): Peralta, Ginette
• Application Number:
  US10/203,729
• Publication Number:
  US 20030141561A1
• Time in Patent Office: 1,741 Days
• Field of Search: 438/717, 438737-739, 438/723
• US Class Current: 438/717
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81C 1/00801 Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer B81C1/00595, B81C1/00468 take precedence
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: B81C 2201/053 Depositing a protective layers
• 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

A method for manufacturing a micromechanical component, that has at least one hollow space and a functional element that is provided at least partially in the hollow space and/or a functional layer that is provided at least partially therein, and a micromechanical component that is manufactured in accordance with the method, are described. To reduce manufacturing costs, the functional element and/or the functional layer is provided with a first protective layer at least in an area that directly or indirectly borders on a first sacrificial layer, which temporarily occupies the space of the hollow space that is subsequently formed in one or a plurality of etching steps, the material of the first protective layer being selected such that at least one etching process and/or etching medium, which etches or dissolves the first sacrificial layer, either does not substantially attack the first protective layer or does so only at a reduced etching rate in comparison to the first sacrificial layer.

Claims

1. A method for manufacturing a micromechanical component including at least one hollow space and at least one of a functional element and a functional layer, the at least one of the functional element and the functional layer provided at least partially in the at least one hollow space, the method comprising:

providing the at least one of the functional element and the functional layer with a first protective layer at least in an area that borders one of directly and indirectly on a first sacrificial layer, a material of the first protective layer being selected so that at least one of an etching process and an etching medium one of;

i) does not substantially attack the first protective layer, and ii) substantially attacks the first protective layer only at a first reduced etching rate in comparison to a first etching rate of the first sacrificial layer, on a side of a second protective layer facing away from the first sacrificial layer, the at least one of the at least one etching process and the etching medium one of etching and dissolving the first sacrificial layer;

forming the at least one hollow space in at least one etching step subsequently to providing the first protective layer, the first sacrificial layer temporarily occupying at least partially a space of the at least one hollow space;

providing a cap layer that at least partially surrounds the at least one hollow space; and

selecting a second material, the at least one of the functional element and the functional layer and at least one of the first sacrificial layer and a second sacrificial layer being substantially composed of the second material.

2. The method according to claim 1, wherein the second material is silicon.

3. The method according to claim 1, wherein the second material is polycrystalline.

4. The method according to claim 1, further comprising:

providing the second protective layer on at least a side of the first sacrificial layer facing away from the at least one of the functional element and the functional layer, a material of the second protective layer being selected so that the at least one of the at least one etching process and the etching medium one of does not substantially attack the second protective layer and substantially attacks the second protective layer only at another reduced etching rate in comparison to the first etching rate.

5. The method according to claim 4, further comprising:

selecting the second sacrificial layer so that at least one of at least one further etching process and a further etching medium one of does not substantially attack the at least one of the functional element and the functional layer and substantially attacks the at least one of the functional element and the functional layer only at another reduced etching rate in comparison to a second etching rate of the second sacrificial layer, the at least one of the at least one further etching process and the further etching medium one of etching and dissolving the second sacrificial layer; and

selecting silicon oxide for the second sacrificial layer;

wherein the at least one of the functional element and the functional layer borders one of directly and indirectly on the second sacrificial layer.

6. The method according to claim 5, further comprising:

providing a third protective layer between the at least one of the functional element and the functional layer and the second sacrificial layer;

selecting the third protective layer so that at least one of at least one further etching process and a further etching medium one of does not substantially attack the third protective layer and substantially attacks the third protective layer only at another reduced etching rate in comparison to a second etching rate of the second sacrificial layer, the at least one of the at least one further etching process and the further etching medium one of etching and dissolving the second sacrificial layer;

selecting silicon oxide for the first sacrificial layer; and

selecting a same third material for the third protective layer and at least one of the first protective layer and the second protective layer.

7. The method according to claim 6, wherein one of:

the first protective layer and the second protective layer all but completely enclose the first sacrificial layer; and

the third protective layer and a fourth protective layer all but completely enclose the second sacrificial layer.

8. The method according to claim 7, further comprising:

selecting a same material for at least one of the first protective layer, the second protective layer, the third protective layer, and the fourth protective layer.

9. The method according to claim 8, wherein silicon oxide is selected for at least one of the first protective layer, the second protective layer, the third protective layer, and the fourth protective layer.

10. The method according to claim 1, further comprising:

removing at least one of the first sacrificial layer and the second sacrificial layer in at least one isotropic etching step.

11. The method according to claim 10, wherein the at least one isotropic etching step includes at least one silicon etching step.