Method for producing a micromechanical component, and a component produced according to said method

• US 20030141561A1
• Filed: 11/08/2002
• Published: 07/31/2003
• Est. Priority Date: 02/10/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Fischer, Frank, Graf, Eckhard, Hein, Peter
• Granted Patent: US 6,951,824 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• 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

The present invention relates to a method for manufacturing a micromechanical component (100), that has at least one hollow space (110) and a functional element (12) that is provided at least partially in the hollow space (110) and/or a functional layer (13a, 13b, 13c) that is provided at least partially therein, and to a micromechanical component (100) that is manufactured in accordance with the method, according to the species of the relevant independent patent claim.

To reduce manufacturing costs, the functional element (12) and/or the functional layer (13a, 13b, 13c) is provided with a first protective layer (41; 71) at least in an area that directly or indirectly borders on a first sacrificial layer (52), which temporarily occupies the space of the hollow space (22) that is subsequently formed in one or a plurality of etching steps (FIG. 4; FIG. 7), the material of the first protective layer (41) being selected such that at least one etching process and/or etching medium, which etches or dissolves the first sacrificial layer (52), either does not substantially attack the first protective layer (41; 71) or does so only at a reduced etching rate in comparison to the first sacrificial layer (52).

Claims

1. A method for manufacturing a micromechanical component (100), which has at least one hollow space (22) and one functional element (12) that is provided at least partially in the hollow space (22) and/or one functional layer (13a, 13b, 13c) that is provided at least partially therein, the functional element (12) and/or the functional layer (13a, 13b, 13c) being provided with a first protective layer (41;

71) at least in an area that directly or indirectly borders on a first sacrificial layer (52), which temporarily occupies at least partially the space of the hollow space (22) that is subsequently formed in one or a plurality of etching steps (FIG. 4;

FIG.

     7), the material of the first protective layer (41;

71) being selected such that at least one etching process and/or etching medium, which etches or dissolves the first sacrificial layer (52), either does not substantially attack the first protective layer (41;

71) or does so only at a reduced etching rate in comparison to the first sacrificial layer (52), on the side of the second protective layer (71) facing away from the first sacrificial layer (52), a cap layer (20;

82) being provided that at least partially surrounds the hollow space (22), and for the functional element (12) and/or for the functional layer (13a, 13b, 13c) and for the first sacrificial layer (52) and/or for the second sacrificial layer (31), at least partially the same material being selected, such as, specifically, silicon, which is preferably polycrystalline.

2. The method as recited in claim 1,

wherein, on at least one side of the first sacrificial layer (52) facing away from the functional element (12) and/or the functional layer (13a, 13b, 13c), a second protective layer (71) is provided on the first sacrificial layer (52) (FIG. 7), the material of the second protective layer (71) being selected such that at least one etching process and/or etching medium, which etches or dissolves the first sacrificial layer (52), either does not substantially attack the second protective layer (71) or does so only at a reduced etching rate in comparison to the first sacrificial layer (52).

3. The method as recited in one of claims 1 through 2,

wherein the functional element (12) and/or the functional layer (13a, 13b, 13c) borders directly or indirectly on a second sacrificial layer (31), and the second sacrificial layer (31) is selected such that at least one etching process and/or etching medium, which etches or dissolves the second sacrificial layer (31), either does not substantially attack the functional element (12) and/or the functional layer (13a, 13b, 13c) or does so only at a reduced etching rate in comparison to the second sacrificial layer (31), silicon being preferably selected for the functional element (12) and/or the functional layer (13a, 13b, 13c) at least on the side facing the second sacrificial layer (31), and silicon oxide being selected for the second sacrificial layer (31).

4. The method as recited in one of claims 1 through 3,

wherein, between the functional element (12) and/or the functional layer (13a, 13b, 13c) and the second sacrificial layer (31), a third protective layer is provided, which is selected such that at least one etching process and/or etching medium, which etches or dissolves the second sacrificial layer (31), either does not substantially attack the third protective layer or does so only at a reduced etching rate in comparison to the second sacrificial layer (31), the second sacrificial layer (31) preferably being made of the same material as the first sacrificial layer (52), such as, specifically, silicon, and/or the third protective layer is made of the same material as the first and/or second protective layer (41, 71), such as, specifically, silicon oxide.

5. The method as recited in one of the preceding claims,

wherein the first protective layer (41) and the second protective layer (71) all but completely enclose the first sacrificial layer (52), and/or the third protective layer and a fourth protective layer all but completely enclose the second sacrificial layer (31).

6. The method as recited in one of claims 1 through 5,

wherein, for the first protective layer (41) and/or for the second protective layer (71) and/or for the third protective layer and/or for the fourth protective layer, at least partially the same material is selected, such as, specifically, an oxide, such as silicon oxide.

7. The method as recited in one of claims 1 through 6,

wherein the first sacrificial layer (52) and/or the second sacrificial layer (31) is removed in one or a plurality of isotropic etching steps, such as, specifically, silicon etching steps.

8. A micromechanical component (100) which has at least one hollow space (22) and one functional element (12) that is provided at least partially in the hollow space (22) and/or one functional layer (13a, 13b, 13c) that is provided at least partially therein,

wherein the component is manufactured in accordance with a method recited in the preceding claims.

9. The micromechanical component as recited in claim 8,

wherein the component (100) is a sensor and/or an actuator component and/or the functional element (12) and/or the functional layer (13a, 13b, 13c) has at least one gap (51c) having a width that is large in relation to the thickness of the functional element (12) and/or the functional layer (13a, 13b, 13c), i.e., a large so-called aspect ratio.