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

• US 9,518,877 B2
• Filed: 09/05/2014
• Issued: 12/13/2016
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Weber, Heribert
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): ESKRIDGE, CORY W
• Application Number:
  US14/478,117
• Publication Number:
  US 20150061049A1
• Time in Patent Office: 830 Days
• Field of Search: 438/53, 438/50, 438/51, 438/52, 438/48, 438/702, 438/127, 438/24, 438/703, 438/705, 438/745, 438/977, 257/415, 257/419, 257/417, 257/414, 257/254, 257/108, 257/420, 257/448, 257/459, 257/534, 257/622, 737/24, 737/18, 737/54, 735/143.2, 737/77, 73/310.6, 733/350.4, 361/283.4, 361/283.1, 216/2, 324/661
• US Class Current: 1/1
• 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 at least partially formed from a layer of at least one of a semiconductor material and a metal; and

a second electrode that includes;

a first layer, an inner side of which faces the first electrode and which is formed from a layer of at least one of a semiconductor material and a metal; and

a second layer above the first layer;

wherein;

the second electrode is suspended above, and at a distance from, the first electrode so that a cavity is present between the first electrode and the second electrode;

recesses (a) are structured into the first layer of the second electrode, and (b) are sealed off by a closure layer;

the second layer of the second electrode;

is a reinforcing layer that increases rigidity of the second electrode;

is formed from a layer of epi-polysilicon material; and

covers at least one subarea of the closure layer; and

the layer of epi-polysilicon material additionally forms at least;

a first contact element that is electrically connected to, and covers a respective surface of, one of (i) the first electrode, (ii) a first printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first electrode is made, and (iii) a conductive substrate area that is in a layer below the layer of the at least one of the semiconductor material and the metal of which the first electrode is made; and

a second contact element that is electrically connected to, and covers a respective surface of, one of (i) the first layer of the second electrode and (ii) a second printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first layer of the second electrode is made.

2. The micromechanical component of claim 1, wherein the recesses form:

at least one of a lattice and mesh pattern; and

in a cross section of the micromechanical component that is in a plane that cuts from a top of the micromechanical component to a bottom of the micromechanical component, a plurality of columns of the first layer of the second electrode spanning over the cavity.

3. The micromechanical component of claim 1, further comprising another epi-polysilicon layer, wherein at least one stress compensation layer is situated between the two epi-polysilicon layers, which are adjacent to each other.

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 second layer of the second electrode layer via at least one of a bonded, soldered, and glued connection.

16. The micromechanical component of claim 2, wherein the second electrode includes at least one stress compensation layer between the first and second layers of the second electrode, and through which the recesses, forming at least one of a lattice or a mesh pattern matching that of the recesses structured in the first layer of the second electrode, are structured.

7. A capacitive sensor device comprising a micromechanical component for a capacitive sensor device, the micromechanical component including:

a first electrode at least partially formed from a layer of at least one of a semiconductor material and a metal; and

a second electrode that includes;

a first layer, an inner side of which faces the first electrode and which is formed from a layer of at least one of a semiconductor material and a metal; and

a second layer above the first layer;

wherein;

the second electrode is suspended above, and at a distance from, the first electrode so that a cavity is present between the first electrode and the second electrode;

recesses (a) are structured into the first layer of the second electrode, and (b) are sealed off by a closure layer;

the second layer of the second electrode;

is a reinforcing layer that increases rigidity of the second electrode;

is formed from a layer of epi-polysilicon material; and

covers at least one subarea of the closure layer; and

the layer of epi-polysilicon material additionally forms at least;

a first contact element that is electrically connected to, and covers a respective surface of, one of (i) the first electrode, (ii) a first printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first electrode is made, and (iii) a conductive substrate area that is in a layer below the layer of the at least one of the semiconductor material and the metal of which the first electrode is made; and

a second contact element that is electrically connected to, and covers a respective surface of, one of (i) the first layer of the second electrode and (ii) a second printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first layer of the second electrode is made.

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 layer of at least one of a semiconductor material and a first metal;

depositing at least one insulating layer above the first electrode;

forming, from a layer of at least one of a semiconductor material and a metal and on the insulating layer, a first layer of a second electrode, an inner side of the first layer of the second electrode facing the first electrode, wherein recesses are structured in the first layer of the second electrode;

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

depositing a closure layer above the first layer of the second electrode, thereby sealing off the recesses after the cavity is formed; and

simultaneously forming, by deposition of a single layer of epi-polysilicon material, (a) a second layer of the second electrode over the closure layer and (b) at least a first contact element and a second contact element, wherein;

the second layer of the second electrode is positioned over at least a portion of the closure layer and is a reinforcing layer that increases rigidity of the second electrode;

the first contact element is electrically connected to, and covers a respective surface of, one of (i) the first electrode, a first printed conductor composed of the same layer of at least one of the semiconductor material and the metal as that of which the first electrode is made, and (iii) a conductive substrate area that is in a layer below the layer of the at least one of the semiconductor material and the metal of which the first electrode is made; and

the second contact element is electrically connected to, and covers a respective surface of, one of (i) the first layer of the second electrode and (ii) a second printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first layer of the second electrode is made.

9. The manufacturing method of claim 8, wherein the first layer of the second electrode is at least partially covered by at least one stress compensation layer, and wherein recesses, forming at least one of a lattice and a mesh pattern matching that of the recesses structured in the first layer of the second electrode, are also structured in the stress compensation layer.

10. The manufacturing method of claim 8, wherein a second layer of epi-polysilicon material is deposited adjacent to the single layer of epi-polysilicon material, and at least one stress compensation layer is deposited between the two adjacent layers of epi-polysilicon material.

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 second layer of the second electrode or to another epi-polysilicon layer over the second layer of the second electrode via at least one of a bonded, soldered, and glued connection.

13. The manufacturing method of claim 12, wherein the first substrate is a silicon on insulator (SOI) wafer and a carrier layer of the SOI wafer is etched off after affixing the second substrate via the at least one of the bonded, soldered, and glued connection.

14. The manufacturing method of claim 8, wherein the etching includes an isotropic oxide plasma etching step.

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

arranging a micromechanical component at least one of in and on the capacitive sensor device;

wherein;

the micromechanical component includes;

a first electrode at least partially formed from a layer of at least one of a semiconductor material and a metal; and

a second electrode that includes;

a first layer, an inner side of which faces the first electrode and which is formed from a layer of at least one of a semiconductor material and a metal; and

a second layer above the first layer;

the second electrode is suspended above, and at a distance from, the first electrode so that a cavity is present between the first electrode and the second electrode;

recesses (a) are structured into the first layer of the second electrode, and (b) are sealed off by a closure layer;

the second layer of the second electrode;

is a reinforcing layer that increases rigidity of the second electrode;

is formed from a layer of epi-polysilicon material; and

covers at least one subarea of the closure layer; and

the layer of epi-polysilicon material additionally forms at least;

a first contact element that is electrically connected to, and covers a respective surface of, one of (i) the first electrode, (ii) a first printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first electrode is made, and (iii) a conductive substrate area that is in a layer below the layer of the at least one of the semiconductor material and the metal of which the first electrode is made; and

a second contact element that is electrically connected to, and covers a respective surface of, one of (i) the first layer of the second electrode and (ii) a second printed conductor composed of the same layer of the at least one of the semiconductor material and the metal as that of which the first layer of the second electrode is made.