MEMS-transducer and method for producing a MEMS-transducer

Patent metadata

Field	Value
Publication number	US-11212624-B2
Application number	US-201916533214-A
Country	US
Kind code	B2
Filing date	Aug 6, 2019
Priority date	Sep 6, 2018
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A MEMS-transducer comprises a membrane structure having a first main surface and a second main surface opposing the first main surface. A substrate structure holds the membrane structure, wherein the substrate structure overlaps with the first main surface of the membrane structure in a first edge region being adjacent to a first inner region of the first main surface. A gap is formed between the membrane structure and the substrate structure in the first edge region and extends from the first inner region into the first edge region.

First claim

What is claimed is:

1. A MEMS-transducer comprising:
a membrane structure having a first main surface and a second main surface opposing the first main surface;
a substrate structure configured to hold the membrane structure, wherein the substrate structure overlaps with the first main surface of the membrane structure in a first edge region being adjacent to a first inner region of the first main surface;
a gap formed between the membrane structure and the substrate structure in the first edge region and extending from the first inner region into the first edge region; and
a carbon material layer arranged in a layer of the gap and in an outer region of the first main surface, the outer region being adjacent to the gap in a direction towards and extending to an outer edge of the membrane structure,
wherein the substrate structure overlaps with the second main surface of the membrane structure in a second edge region being adjacent to a second inner region of the second main surface, wherein the MEMS-transducer comprises a second gap formed between the membrane structure and the substrate structure in the second edge region and extending from the second inner region into the second edge region,
wherein the membrane structure comprises a vibratable membrane structure and the MEMS-transducer comprises a passivated MEMS-transducer, and
wherein within a tolerance range of 10%, the first and second edge region comprise a same extension perpendicular to a surface normal of the first main surface,
wherein the carbon material layer is in direct physical contact with the entirety of the first main surface of the membrane structure in the outer region and/or is in direct physical contact with the entirety of the second main surface of the membrane structure in the outer region, and the carbon material layer provides for a clamping of the membrane structure.

2. The MEMS-transducer of claim 1 , wherein the first edge region overlaps with a larger portion of the first main surface when compared to a portion of the second main surface being overlapped by the substrate structure in a second edge region of the second main surface.

3. The MEMS-transducer of claim 1 , wherein a surface normal of the first main surface directs along a thickness direction of the membrane structure, wherein the gap comprises a first extension along the thickness direction, the first extension being at least 1 nm and at most 40 nm.

4. The MEMS-transducer of claim 1 , wherein a surface normal of the first main surface directs along a thickness direction of the membrane structure, wherein the gap comprises a second extension perpendicular to the thickness direction and towards an outer edge of the membrane structure starting from the first inner region, the second extension being at least 1 μm and at most 200 μM.

5. The MEMS-transducer of claim 1 , wherein an ash material is arranged in the gap between the substrate structure and the membrane structure.

6. The MEMS-transducer of claim 1 , wherein, in a projection into the first main surface, the gap overlaps with a region of the substrate structure to which the second main surface is mechanically fixed, by at least 1 μm.

7. A method for producing a MEMS-transducer, the method comprising:
arranging a layer stack comprising a membrane structure, a substrate structure holding the membrane structure and a carbon layer arranged between the membrane structure and the substrate structure;
removing the carbon layer at least partially so as to generate a gap between the membrane structure and the substrate structure in a first edge region, such that the gap extends from a first inner region of a first main surface of the membrane structure into a first edge region in which the substrate structure overlaps with the first main surface of the membrane structure, the first edge region being adjacent to the first inner region of the first main surface,
wherein removing of the carbon layer is performed after a substrate etching, for releasing the membrane structure such that the membrane is vibratable and/or performed after passivating the MEMS-transducer,
wherein the substrate etching is performed so as to release a first inner region of a first main surface of the membrane structure with exception of a first edge region and so as to release a second inner region of a second main surface of the membrane structure with exception of a second edge region, and
wherein within a tolerance range of 10%, the first and second edge region comprise a same extension perpendicular to a surface normal of the first main surface.

8. The method of claim 7 , wherein removing of the carbon layer comprises execution of an etching process using oxidation such that an ash material is obtained as a remains on the membrane structure.

9. A MEMS-transducer comprising:
a membrane structure having a first main surface and a second main surface opposing the first main surface;
a substrate structure configured to hold the membrane structure, wherein the substrate structure overlaps with the first main surface of the membrane structure in a first edge region being adjacent to a first inner region of the first main surface; and
a gap formed between the membrane structure and the substrate structure in the first edge region and extending from the first inner region into the first edge region,
wherein the gap is a first gap, wherein the substrate structure overlaps with the second main surface of the membrane structure in a second edge region being adjacent to a second inner region of the second main surface, wherein the MEMS-transducer comprises a second gap formed between the membrane structure and the substrate structure in the second edge region and extending from the second inner region into the second edge region; and
a third gap arranged at a side surface of the membrane structure, connecting the first main surface and the second main surface, wherein the first, second and third gap provide for a slack holding of the membrane structure by the substrate structure such that the membrane structure is not physically coupled to the substrate structure, and
wherein the first main surface of the membrane structure is completely planar in the first edge region and the second main surface of the membrane structure is completely planar in the second edge region, and wherein the third gap is defined by a vertical sidewall of the substrate structure and a vertical sidewall of the membrane structure.

10. The MEMS-transducer of claim 9 , wherein the gap completely uncovers the first main surface from the substrate structure.

Assignees

• Infineon Technologies Ag

Inventors

• Klein Wolfgang
• Gierl Karolina
• Meyer Markus

Classifications

• B81B3/0051 Primary

  For defining the movement, i.e. structures that guide or limit the movement of an element (mechanical arrangements for preventing or damping vibration or shock H01H3/60) · CPC title

• H04R19/005 Primary

  using semiconductor materials · CPC title

• B81C1/00158

  Diaphragms, membranes (manufacture process for semi-permeable inorganic membranes B01D67/0039) · CPC title

• H04R19/04

  Microphones (H04R19/01 takes precedence) · CPC title

• H04R31/003

  for diaphragms or their outer suspension · CPC title