Production method for a micromechanical component

Patent metadata

Field	Value
Publication number	US-11905166-B2
Application number	US-202117446898-A
Country	US
Kind code	B2
Filing date	Sep 3, 2021
Priority date	Sep 15, 2020
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A production method for a micromechanical component for a sensor or microphone device. The method includes: patterning a plurality of first trenches through a substrate surface of a monocrystalline substrate made of at least one semiconductor material using anisotropic etching, covering the lateral walls of the plurality of first trenches with a passivation layer, while bottom areas of the plurality of first trenches are kept free or are freed of the passivation layer, etching at least one first cavity, into which the plurality of first trenches opens, into the monocrystalline substrate using an isotropic etching method, in which an etching medium of the isotropic etching method is conducted through the plurality of first trenches, and by covering the plurality of first trenches by epitaxially growing a monocrystalline sealing layer on the substrate surface of the monocrystalline substrate made of the at least one identical semiconductor material as the monocrystalline substrate.

First claim

What is claimed is:

1. A production method comprising the following steps:
patterning a plurality of first trenches through a substrate surface of a monocrystalline substrate, the monocrystalline substrate being made of at least one semiconductor material, using an anisotropic etching method;
covering lateral walls of the plurality of first trenches with a passivation layer, while bottom areas of the plurality of first trenches are kept free or are freed of the passivation layer;
etching at least one first cavity, into which the plurality of first trenches open, into the monocrystalline substrate using an isotropic etching method, in which an etching medium of the isotropic etching method is conducted through the plurality of first trenches;
covering the plurality of first trenches by epitaxially growing a monocrystalline sealing layer on the substrate surface of the monocrystalline substrate, wherein the monocrystalline sealing layer is made of at least one identical semiconductor material as the monocrystalline substrate;
forming at least one semiconductor and/or metal layer and/or at least one insulating layer, as a layer stack on and/or over the monocrystalline sealing layer on a side of the monocrystalline sealing layer facing away from the at least one first cavity; and
forming at least one second cavity by removing at least one partial area of the at least one semiconductor and/or metal layer and/or of the at least one insulating layer on the side of the monocrystalline sealing layer oriented away from the at least one first cavity, with a remaining portion of the at least one semiconductor and/or metal layer and/or of the at least one insulating layer surrounding the at least one second cavity;
wherein:
the production method results in a micromechanical component for a sensor or microphone device, the micromechanical component including:
the monocrystalline substrate made of the at least one semiconductor material, with the plurality of first trenches (a) patterned through the substrate surface of the monocrystalline substrate and (b) opening into the at least one first cavity etched into the monocrystalline substrate;
the monocrystalline sealing layer that (a) is epitaxially grown on the substrate surface of the monocrystalline substrate, (b) is made of the at least one identical semiconductor material as the monocrystalline substrate, and (c) covers the plurality of first trenches; and
the remaining portion of the at least one semiconductor and/or metal layer and/or at least one insulating layer that (a) is formed as the layer stack on the side of the monocrystalline sealing layer facing away from the at least one first cavity and (b) surrounds at least one second cavity; and

in the resulting micromechanical component:
a partial area, adjoining the at least one second cavity, of an outermost silicon layer of the layer stack is developed as a deformable diaphragm; and
at least one connecting channel is formed, by which the at least one first cavity formed within the monocrystalline substrate is connected to the at least one second cavity embedded in the layer stack.

2. The production method as recited in claim 1 , wherein the monocrystalline sealing layer is epitaxially grown as a monocrystalline silicon layer on the monocrystalline substrate made of silicon.

3. A micromechanical component for a sensor or microphone device, comprising:
a monocrystalline substrate made of at least one semiconductor material, a plurality of first trenches being patterned through a substrate surface of the monocrystalline substrate, wherein the plurality of first trenches open into at least one first cavity etched into the monocrystalline substrate;
a monocrystalline sealing layer that (a) is epitaxially grown on the substrate surface of the monocrystalline substrate, (b) is made of at least one identical semiconductor material as the monocrystalline substrate, and (c) covers the plurality of first trenches; and
at least one semiconductor and/or metal layer and/or at least one insulating layer, formed as a layer stack on a side of the monocrystalline sealing layer facing away from the at least one first cavity, the at least one semiconductor and/or metal layer and/or the at least one insulating layer surrounding at least one second cavity;
wherein a partial area, adjoining the at least one second cavity, of an outermost silicon layer of the layer stack is developed as a deformable diaphragm, and at least one connecting channel is formed, by which the at least one first cavity formed within the monocrystalline substrate is connected to the at least one second cavity embedded in the layer stack.

Assignees

• Bosch Gmbh Robert

Inventors

• Weber Heribert
• Schmollngruber Peter
• Friedrich Thomas
• Scheurle Andreas
• Fritz Joachim
• Mach Sophielouise

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

• B81B2201/0264

  Pressure sensors · CPC title

• B81B2203/0127

  Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function · CPC title