Production method for a micromechanical component for a sensor device or microphone device

Patent metadata

Field	Value
Publication number	US-2023357001-A1
Application number	US-202118246790-A
Country	US
Kind code	A1
Filing date	Sep 30, 2021
Priority date	Oct 15, 2020
Publication date	Nov 9, 2023
Grant date	—

Abstract

A production method for a micromechanical component for a sensor device or microphone device. The method includes: forming a supporting structure composed of a first sacrificial material on a substrate surface of a substrate with a first sacrificial material layer, a plurality of etching holes structured through the first sacrificial material layer, and a plurality of supporting posts projecting into the substrate; etching into the substrate surface at least one cavity spanned by the supporting structure; forming a diaphragm composed of at least one semiconductor material on or over the first sacrificial material layer of the supporting structure; depositing a layer stack comprising at least one sacrificial layer and at least one counter electrode; and exposing the diaphragm by at least partially removing at least the supporting structure and the at least one sacrificial layer.

First claim

1 - 10 . (canceled)

11 . A production method for a micromechanical component for a sensor device or microphone device, the method comprising the following steps:
forming a supporting structure including a first sacrificial material on a substrate surface of a substrate, the supporting structure being formed using a first sacrificial material layer including the first sacrificial material at least partially covering the substrate surface, the sacrificial material layer including a plurality of etching holes structured through the first sacrificial material layer, and using a plurality of supporting posts including the first sacrificial material projecting into the substrate; etching into the substrate surface at least one cavity spanned by the supporting structure using an etchant passed through the plurality of etching holes in the first sacrificial material layer, the first sacrificial material having a higher etch resistance to the etchant than the substrate; forming a diaphragm including at least one semiconductor material on or over the first sacrificial material layer of the supporting structure; depositing a layer stack on a side of the diaphragm facing away from the substrate, the layer stack including at least one sacrificial layer and at least one counter electrode formed on a side of the at least one sacrificial layer facing away from the diaphragm; and exposing the diaphragm by at least partially removing at least the supporting structure and the at least one sacrificial layer.

12 . The production method as recited in claim 11 , wherein to form the supporting structure including the first sacrificial material on the substrate surface of the substrate the following steps are performed:
structuring a plurality of trenches into the substrate surface of the substrate; depositing the first sacrificial material on the substrate surface with the plurality of trenches structured therein such that the plurality of supporting posts projecting into the substrate are formed from the first sacrificial material filled into the plurality of trenches and the substrate surface is at least partially covered with the subsequent first sacrificial material layer including the first sacrificial material; structuring the plurality of etching holes through the first sacrificial material layer; and etching the cavity into the substrate surface through the plurality of etching holes in the first sacrificial material layer.

13 . The production method as recited in claim 11 , wherein, before the diaphragm is formed, the first sacrificial material layer is at least partially covered with a second sacrificial material layer including the first sacrificial material and/or a second sacrificial material, and wherein, when the diaphragm is being formed, the second sacrificial material layer is at least partially covered by the diaphragm.

14 . The production method as recited in claim 11 , wherein the supporting structure is formed from silicon dioxide as the first sacrificial material.

15 . The production method as recited in claim 14 , wherein, before the diaphragm is formed, silicon-rich silicon nitride and/or silicon nitride and/or silicon carbide, and/or aluminum oxide is deposited locally on the first sacrificial material layer including silicon dioxide, and/or on the second sacrificial material layer including silicon dioxide, and/or in at least one aperture structured through the first sacrificial material layer including silicon dioxide.

16 . The production method as recited in claim 11 , wherein, to expose the diaphragm, at least one first etchant access extending through the layer stack, at least one second etchant access extending only through a part of the layer stack, and/or a channel extending through the substrate, is formed, and at least the supporting structure and the at least one sacrificial layer are at least partially removed using at least one etchant passed through the at least one first etchant access, and/or through the at least one second etchant access, and/or through the at least one channel.

17 . The production method as recited in claim 11 , wherein, to feed pressure to the diaphragm, at least one channel is formed, extending through the substrate into free space between the diaphragm and the substrate.

18 . A micromechanical component for a sensor device or microphone device, comprising:
a substrate having a substrate surface, on which a diaphragm including at least one semiconductor material is stretched in such a way that the diaphragm spans at least one free space etched into the substrate surface; and a layer stack deposited on a side of the diaphragm facing away from the substrate, having at least one counter electrode, with a void being formed in the layer stack between the diaphragm and the at least one counter electrode, the void being bordered by the diaphragm.

19 . The micromechanical component as recited in claim 18 , wherein a maximum gap width of the free space oriented perpendicularly to the substrate surface is greater than or equal to 5 μm.

20 . The micromechanical component as recited in claim 18 , wherein a plurality of trenches are etched into the substrate on a side of the free space facing away from the diaphragm and bordering the substrate.

Assignees

• Bosch Gmbh Robert

Inventors

• Weber Heribert
• Scheurle Andreas
• Artmann Hans
• Schmollngruber Peter
• Friedrich Thomas
• Schiller Uwe

Classifications

• B81C1/00158 Primary

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

• B81B3/0021

  Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00) · CPC title

• B81B2201/0257

  Microphones or microspeakers · CPC title

• B81C2201/0105

  Sacrificial layer · CPC title

• B81C2201/014

  by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal · CPC title