Micromechanical component for a capacitive sensor device, and manufacturing method for a micromechanical component for a capacitive sensor device

• US 20150061049A1
• Filed: 09/05/2014
• Published: 03/05/2015
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: WEBER, Heribert
• Granted Patent: US 9,518,877 B2
• Time in Patent Office: Days
• US Class Current: 257/417
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 3/007 For controlling stiffness, e.g. ribs
• CPC Class Codes: G01L 1/148 using semiconductive material, e.g. silicon
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 29/66007 Multistep manufacturing processes

Abstract

A micromechanical component for a capacitive sensor device includes first and second electrodes. The first electrode is at least partially formed from a first semiconductor layer and/or metal layer, and at least one inner side of the second electrode facing the first electrode is formed from a second semiconductor layer and/or metal layer. A cavity is between the first and second electrodes. Continuous recesses are structured into the inner side of the second electrode and sealed off with a closure layer. At least one reinforcing layer of the second electrode and at least one contact element which is electrically connected to the first electrode, to the layer of the second electrode which forms the inner side, to at least one printed conductor, and/or to a conductive substrate area, are formed from at least one epi-polysilicon layer. Also described is a micromechanical component manufacturing method for a capacitive sensor device.

Claims

1. A micromechanical component for a capacitive sensor device, comprising:

a first electrode; and

a second electrode, the first electrode being at least partially formed from a first semiconductor layer and/or metal layer, and at least one inner side of a layer of the second electrode facing the first electrode being formed from a second semiconductor layer and/or metal layer;

wherein the second electrode is suspended at a distance from the first electrode so that a cavity is present between the first electrode and the second electrode, and continuous recesses are structured into the layer of the second electrode which forms the inner side, and being sealed off with the aid of a closure layer,

wherein at least one reinforcing layer of the second electrode and at least one contact element which is electrically connected to the first electrode, to the layer of the second electrode which forms the inner side, to a first printed conductor composed of the first semiconductor layer and/or metal layer, to a second printed conductor composed of the second semiconductor layer and/or metal layer, and/or to a conductive substrate area, are formed from at least one epi-polysilicon layer so that at least one subarea of the closure layer which seals off the continuous recesses and at least one subsurface of the first electrode, of the layer of the second electrode which forms the inner side, of the first printed conductor, of the second printed conductor, and/or of the conductive substrate area which is exposed with the aid of at least one contact opening, are covered with the aid of the single epi-polysilicon layer or with the aid of the innermost of the at least two epi-polysilicon layers.

2. The micromechanical component of claim 1, wherein the second electrode includes at least one stress compensation layer which is situated between the layer of the second electrode which forms the inner side and the at least one reinforcing layer, and through which the continuous recesses are structured.

3. The micromechanical component of claim 1, wherein the micromechanical component includes at least two epi-polysilicon layers as the at least one epi-polysilicon layer, and wherein at least one stress compensation layer is situated between two adjacent epi-polysilicon layers.

4. The micromechanical component of claim 1, further comprising:

an intermediate electrode which is situated between the first electrode and the second electrode.

5. The micromechanical component of claim 1, further comprising:

a first substrate having a top side which is at least partially covered by an insulating layer, the first electrode being situated on the insulating layer.

6. The micromechanical component of claim 1, further comprising:

a second substrate which is affixed to the at least one epi-polysilicon layer via at least one bonded, soldered, and/or glued connection.

7. A capacitive sensor device, comprising:

a micromechanical component for a capacitive sensor device, including;

a first electrode; and

a second electrode, the first electrode being at least partially formed from a first semiconductor layer and/or metal layer, and at least one inner side of a layer of the second electrode facing the first electrode being formed from a second semiconductor layer and/or metal layer;

wherein the second electrode is suspended at a distance from the first electrode so that a cavity is present between the first electrode and the second electrode, and continuous recesses are structured into the layer of the second electrode which forms the inner side, and being sealed off with the aid of a closure layer,

wherein at least one reinforcing layer of the second electrode and at least one contact element which is electrically connected to the first electrode, to the layer of the second electrode which forms the inner side, to a first printed conductor composed of the first semiconductor layer and/or metal layer, to a second printed conductor composed of the second semiconductor layer and/or metal layer, and/or to a conductive substrate area, are formed from at least one epi-polysilicon layer so that at least one subarea of the closure layer which seals off the continuous recesses and at least one subsurface of the first electrode, of the layer of the second electrode which forms the inner side, of the first printed conductor, of the second printed conductor, and/or of the conductive substrate area which is exposed with the aid of at least one contact opening, are covered with the aid of the single epi-polysilicon layer or with the aid of the innermost of the at least two epi-polysilicon layers.

8. A manufacturing method for a micromechanical component for a capacitive sensor device, the method comprising:

forming a first electrode at least partially from a first semiconductor layer and/or metal layer; and

depositing at least one insulating layer above the first electrode;

forming on the insulating layer at least one inner side of a layer of a second electrode facing the first electrode from a second semiconductor layer and/or metal layer, continuous recesses being structured through the layer of the second electrode which forms the inner side;

forming a cavity between the first electrode and the layer of the second electrode which forms the inner side by etching off a subarea at least of the insulating layer through the continuous recesses;

sealing off the continuous recesses with the aid of a closure layer after the cavity is formed;

forming at least one reinforcing layer of the second electrode and at least one contact element which is electrically connected to the first electrode, to the layer of the second electrode which forms the inner side, to a first printed conductor composed of the first semiconductor layer and/or metal layer, to a second printed conductor composed of the second semiconductor layer and/or metal layer, and/or to a conductive substrate area, from at least one epi-polysilicon layer;

wherein at least one subarea of the closure layer which seals off the continuous recesses and at least one subsurface of the first electrode, of the layer of the second electrode which forms the inner side, of the first printed conductor, of the second printed conductor, and/or of the conductive substrate area which is exposed with the aid of at least one contact opening, are covered with the aid of the single epi-polysilicon layer or with the aid of the innermost of the at least two epi-polysilicon layers.

9. The manufacturing method of claim 8, wherein the inner side of the second electrode is at least partially covered by at least one stress compensation layer, and wherein the continuous recesses are also structured through the stress compensation layer.

10. The manufacturing method of claim 8, wherein at least two epi-polysilicon layers are deposited as the at least one epi-polysilicon layer, and wherein at least one stress compensation layer is deposited between two adjacent epi-polysilicon layers.

11. The manufacturing method of claim 8, wherein prior to depositing the insulating layer, an intermediate insulating layer is deposited on the first electrode, and wherein an intermediate electrode which is at least partially covered by the insulating layer is formed on the intermediate insulating layer.

12. The manufacturing method of claim 8, wherein the first electrode is formed on at least one additional insulating layer which at least partially covers a top side of a first substrate, and wherein a second substrate is affixed to the at least one epi-polysilicon layer via at least one bonded, soldered, and/or glued connection.

13. The manufacturing method of claim 12, wherein the first substrate is etched off at the at least one epi-polysilicon layer after affixing the second substrate via the at least one bonded, soldered, and/or glued connection.

14. The manufacturing method of claim 8, wherein the formation of the cavity between the first electrode and the layer of the second electrode which forms the inner side takes place by etching off the subarea at least of the insulating layer with the aid of an isotropic oxide plasma etching step.

15. A manufacturing method for a capacitive sensor device, the method comprising:

arranging a micromechanical component in and/or on the capacitive sensor device;

wherein the micromechanical component includes;

a first electrode; and

a second electrode, the first electrode being at least partially formed from a first semiconductor layer and/or metal layer, and at least one inner side of a layer of the second electrode facing the first electrode being formed from a second semiconductor layer and/or metal layer;

wherein the second electrode is suspended at a distance from the first electrode so that a cavity is present between the first electrode and the second electrode, and continuous recesses are structured into the layer of the second electrode which forms the inner side, and being sealed off with the aid of a closure layer,

wherein at least one reinforcing layer of the second electrode and at least one contact element which is electrically connected to the first electrode, to the layer of the second electrode which forms the inner side, to a first printed conductor composed of the first semiconductor layer and/or metal layer, to a second printed conductor composed of the second semiconductor layer and/or metal layer, and/or to a conductive substrate area, are formed from at least one epi-polysilicon layer so that at least one subarea of the closure layer which seals off the continuous recesses and at least one subsurface of the first electrode, of the layer of the second electrode which forms the inner side, of the first printed conductor, of the second printed conductor, and/or of the conductive substrate area which is exposed with the aid of at least one contact opening, are covered with the aid of the single epi-polysilicon layer or with the aid of the innermost of the at least two epi-polysilicon layers.