Structures for reducing and avoiding stresses on the seal bottom side during laser reseal

Patent metadata

Field	Value
Publication number	US-10023460-B2
Application number	US-201615333381-A
Country	US
Kind code	B2
Filing date	Oct 25, 2016
Priority date	Oct 26, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A method for manufacturing a micromechanical component including a substrate and including a cap, which is connected to the substrate and, together with the substrate, encloses a first cavity, a first pressure prevailing and a first gas mixture having a first chemical composition being enclosed in the first cavity. An access opening connecting the first cavity to surroundings of the micromechanical component is formed in the substrate or in the cap. The first pressure and/or the first chemical composition is adjusted in the first cavity. The access opening is sealed by introducing energy or heat via laser into an absorbing part of the substrate or the cap. During the step for forming the access opening, a first access opening section is formed generally perpendicularly to a surface of the substrate or the cap, and a second access opening section is formed generally perpendicularly to and in parallel to the surface.

First claim

What is claimed is:

1. A method for manufacturing a micromechanical component including a substrate, and a cap which is connected to the substrate and, together with the substrate, encloses a first cavity, a first pressure prevailing and a first gas mixture having a first chemical composition being enclosed in the first cavity, the method comprising:
in a first step, forming an access opening connecting the first cavity to surroundings of the micromechanical component in the substrate or in the cap;
in a second step, adjusting at least one of the first pressure and the first chemical composition in the first cavity;
in a third step, sealing the access opening by introducing energy or heat into an absorbing part of the substrate or the cap, with the aid of a laser;
in a first sub-step during the first step, forming a first access opening section perpendicularly to a surface of the substrate or the cap; and
in a second sub-step during the first step, forming a second access opening section in parallel to the surface to relieve mechanical stresses occurring when the access opening is sealed.

2. The method as recited in claim 1 , wherein the cap, together with the substrate, encloses a second cavity, a second pressure prevailing and a second gas mixture having a second chemical composition being enclosed in the second cavity.

3. The method as recited in claim 1 , further comprising:
in a third sub-step during the first step, a third access opening section is formed perpendicularly to the surface.

4. The method as recited in claim 3 , wherein at least one of:
the first access opening section is formed with the aid of anisotropic etching;
the second access opening section is formed with the aid of isotropic etching; and
the third access opening section is formed with the aid of anisotropic etching.

5. The method as recited in claim 1 , wherein the second access opening section is configured in such a way that a first distance, extending perpendicularly to the surface, between the second access opening section and the surface is at a maximum twice as large as a second distance, extending perpendicularly to the surface, between a maximum extension of the absorbing part and the surface.

6. The method as recited in claim 1 , wherein the second access opening section is configured in such a way that a ratio between a depth extending perpendicularly from the surface to where the second access opening section begins and a distance, extending perpendicularly to the surface, between the surface and a maximum extension of the absorbing part, is at most 2.

7. The method as recited in claim 1 , wherein the second access opening section is configured in such a way that a ratio between a width of the second access opening section extending in parallel to the surface and a third distance, extending perpendicularly to the surface, between the second access opening section and a maximum extension of the absorbing part, is equal to or greater than 1.

8. The method as recited in claim 1 , wherein the second access opening section is configured in such a way that the absorbing part of the substrate or of the cap and the material of the substrate or of the cap surrounding the second access opening section at least partially overlap.

Assignees

• Bosch Gmbh Robert

Inventors

• Breitling Achim
• Reichenbach Frank
• Reinmuth Jochen
• Amthor Julia

Classifications

• B81B2201/0235

  Accelerometers · CPC title

• B81B2201/0242

  Gyroscopes · CPC title

• B81C2201/013

  Etching · CPC title

• B81B7/0051 Primary

  between the package lid and the substrate · CPC title

• B81C2203/0145

  Hermetically sealing an opening in the lid · CPC title