Microsystem with integrated circuit and micromechanical component, and production process

• US 5,611,940 A
• Filed: 04/28/1995
• Issued: 03/18/1997
• Est. Priority Date: 04/28/1994
• Status: Expired due to Term

• Current Assignee: Infineon Technologies AG
• Original Assignee: Siemens AG
• Inventors: Zettler, Thomas
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US08/431,499
• Time in Patent Office: 690 Days
• Field of Search: 216/2, 216/41, 216/79, 216/99, 156/656.1, 156/657.1, 156/659.11, 437/927, 310/310, 310/323, 310/329, 73/517 R
• US Class Current: 73/514.16
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: G01L 1/148 using semiconductive material, e.g. silicon
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H02N 1/002 Electrostatic motors

Abstract

A microsystem on a semiconductor substrate includes an integrated circuit having an insulating layer, a contact in the insulating layer, a lower-lying circuit element, and a conductive layer being disposed above the insulating layer and being connected through the contact to the lower-lying circuit element. A micromechanical component has a fixed micromechanical structure, a movable micromechanical structure, a further contact, and is at least partially formed of the conductive layer. The insulating layer and/or the further contact connects the fixed micromechanical structure to the substrate. The insulating layer is absent under the movable micromechanical structure. A production process for the microsystem includes structuring the conductive layer for producing the fixed and movable micromechanical structures, while simultaneously structuring the conductive layer in the region of the integrated circuit; and exposing the movable micromechanical structure by removing the insulating layer located under the movable micromechanical structure in an etching process having adequate selectively for the conductive layer and having an isotropic component.

Claims

1. A microsystem on a semiconductor substrate, comprising:

an integrated circuit having an insulating layer, a contact in said insulating layer, a lower-lying circuit element, and a conductive layer being disposed above said insulating layer and being connected through said contact to said lower-lying circuit element;

a micromechanical component having a fixed micromechanical structure, a movable micromechanical structure, and being at least partially formed of said conductive layer;

said fixed micromechanical structure being connected to a semiconductor substrate; and

said insulating layer being absent under said movable micromechanical structure.

2. The microsystem according to claim 1, wherein said movable micromechanical structure is freely movable.

3. The microsystem according to claim 1, wherein said movable micromechanical structure is resiliently movable.

4. The microsystem according to claim 1, wherein said integrated circuit has a plurality of conductive layers in the form of a multilayer metallization, and said micromechanical structures are formed of a plurality of metallizing layers.

5. The microsystem according to claim 1, wherein said integrated circuit has an at least single layer metallization with said conductive layer, and all of said micromechanical structures are formed of said conductive layer.

6. The microsystem according to claim 2, including a security device for preventing said freely movable micromechanical structure from falling out, said security device being formed from a different metallizing layer than said movable structure.

7. The microsystem according to claim 1, wherein said integrated circuit has a plurality of conductive layers, at least one of said conductive layers is formed of an aluminum alloy, and said insulating layer is formed of a silicon oxide.

8. The microsystem according to claim 1, wherein said integrated circuit has a plurality of conductive layers, at least one of said conductive layers is formed substantially of tungsten, and said insulating layer is formed of a silicon oxide.

9. The microsystem according to claim 1, wherein said micromechanical component is selected from the group consisting of a proportional force sensor, a non-proportional force sensor, an oscillator, and a resonator.

10. The microsystem according to claim 1, wherein said micromechanical component is selected from the group consisting of a micromotor and a microactuator.

11. The microsystem according to claim 1, wherein said integrated circuit includes a trigger or evaluation circuit for said micromechanical component and a plurality of conductive layers, and including a line being made from at least one of said conductive layers for connecting said trigger or evaluation circuit to said component.

16. The microsystem according to claim 1, wherein said micromechanical component includes a further contact which connects said fixed micromechanical structure to the semiconductor substrate.

17. The microsystem according to claim 16, wherein said insulating layer and said further contact connect said fixed micromechanical structure to the semiconductor substrate.

18. The microsystem according to claim 1, wherein said insulating layer connects said fixed micromechanical structure to the semiconductor substrate.

12. A production process for a microsystem including an integrated circuit having an insulating layer and a conductive layer on the insulating layer;

and a micromechanical component having a fixed micromechanical structure and a movable micromechanical structure, which comprises;

structuring the conductive layer for producing the fixed and movable micromechanical structures, while simultaneously structuring the conductive layer in the region of the integrated circuit; and

exposing the movable micromechanical structure by removing the insulating layer located under the movable micromechanical structure in an etching process having adequate selectively for the conductive layer and having an isotropic component.

13. The production process according to claim 12, which comprises carrying out the etching step as a microwave-supported isotropic dry etching.

14. The production process according to claim 12, which comprises carrying out the etching step with a buffered HF solution.

15. The production process according to claim 12, which comprises producing the integrated circuit and the micromechanical component with a plurality of conductive layers, covering the conductive layers with further insulating layers, and etching the insulating layers in the etching step with adequate selectively for the conductive layers.