Laser resealing with stress-reducing prestructuring

Patent metadata

Field	Value
Publication number	US-10556789-B2
Application number	US-201615297794-A
Country	US
Kind code	B2
Filing date	Oct 19, 2016
Priority date	Oct 26, 2015
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A method for manufacturing a micromechanical component including a substrate and a cap connected to the substrate and together with the substrate enclosing a first cavity, a first pressure prevailing and a first gas mixture with a first chemical composition being enclosed in the first cavity: in a first method step, an access opening, connecting the first cavity to surroundings of the micromechanical component, being formed in the substrate or in the cap; in a second method step, the first pressure and/or the first chemical composition being adjusted in the first cavity; in a third method step, the access opening being sealed by introducing energy and heat into an absorbing part of the substrate or the cap with the aid of a laser; in a fourth method step, a recess being formed, and/or an elevation being formed, and/or a reflection area being formed, and/or an absorption area being formed.

First claim

What is claimed is:

1. A method for manufacturing a micromechanical component including a substrate and a cap connected to the substrate and together with the substrate enclosing a first cavity, a first pressure prevailing and a first gas mixture with 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, forming a receptacle at a surface of the substrate or of the cap in a region of the access opening, wherein the receptacle includes a base, an open side opposite the base and facing away from the first cavity, and a sidewall that separates the receptacle from the access opening; and
in a fourth step, using a laser to introduce energy and heat into the receptacle towards the base of the receptacle, and thereby into an absorbing part of the substrate or the cap, which converts material of the substrate or the cap around the receptacle into a liquid aggregate that fills at least a part of the receptacle and a mouth of the access opening, thereby sealing the access opening.

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 with a second chemical composition being enclosed in the second cavity.

3. The method as recited in claim 1 , wherein the receptacle is formed in such a way that the liquid aggregate solidifies into solidified material situated between a plane extending along the surface and the first cavity.

4. The method as recited in claim 1 , wherein the receptacle is formed in such a way that a first surface, which is of a projection of the receptacle onto a plane extending along the surface is smaller than a second surface, which is of a projection of solidified material formed by solidification of the liquid aggregate onto the plane.

5. The method as recited in claim 1 , wherein the receptacle is formed so that, in at least one plane, an edge of the receptacle closest to the access channel is spaced twice as far from a center point of the access channel as a maximum extension of the access channel is spaced apart from the center point in the at least one plane.

6. The method as recited in claim 1 , wherein the formation of the receptacle is performed by forming a recess in the substrate or the cap.

7. The method as recited in claim 1 , wherein the formation of the receptacle includes forming an elevation on a surface of the substrate or the cap.

8. The method as recited in claim 1 , wherein the receptacle is annular and surrounds the access opening, the sidewall being a radially interior annular wall of the receptacle.

9. The method as recited in claim 8 , wherein the liquid aggregate solidifies, thereby forming an annular ridge circling a location of the sealed access opening.

10. The method as recited in claim 8 , wherein the annular receptacle is rotationally symmetrical relative to the access opening.

11. The method as recited in claim 8 , wherein the annular receptacle is rotationally symmetrical relative to a center of mass of solidified material formed by solidification of the liquid aggregate.

12. The method as recited in claim 9 , wherein the annular ridge is rotationally symmetrical and ring shaped, with respect to the access channel or to a center of mass of solidified material into which the liquid aggregate solidifies.

13. The method as recited in claim 1 , wherein the conversion of the material of the substrate or cap around the receptacle into the liquid aggregate includes melting an upper edge of the sidewall.

14. The method as recited in claim 1 , wherein the conversion of the material of the substrate or cap around the receptacle into the liquid aggregate includes melting an upper edge of the sidewall, without melting of at least a part of the sidewall below the upper edge.

15. A method for manufacturing a micromechanical component including a substrate and a cap connected to the substrate and together with the substrate enclosing a first cavity, a first pressure prevailing and a first gas mixture with 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, forming a reflection area on or in the surface of the substrate or of the cap facing away from the first cavity in an area of the access opening for increased reflection, in contrast to a remainder of the surface, of laser radiation; and
in a fourth step, using a laser to expose the surface to the laser radiation, thereby introducing energy and heat into part of the substrate or the cap, thereby sealing the access opening.

16. A method for manufacturing a micromechanical component including a substrate and a cap connected to the substrate and together with the substrate enclosing a first cavity, a first pressure prevailing and a first gas mixture with 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, forming an absorption area on or in the surface of the substrate or of the cap facing away from the first cavity in an area of the access opening for increased absorption, in contrast to a remainder of the surface, of laser radiation; and
in a fourth step, using a laser to expose the surface to the laser radiation, thereby introducing energy and heat into part of the substrate or the cap, thereby sealing the access opening.

Assignees

• Bosch Gmbh Robert

Inventors

• Reichenbach Frank
• Reinmuth Jochen
• Kappe Philip
• Ametowobla Mawuli

Classifications

• B81C2203/036

  Fusion bonding · CPC title

• B81C2203/0145

  Hermetically sealing an opening in the lid · CPC title

• B81B2203/0315

  Cavities · CPC title

• B81C1/00269

  Bonding of solid lids or wafers to the substrate · CPC title

• B81C1/00333

  Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325 · CPC title