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US 6,787,052 B1Granted
Method for fabricating microstructures with deep anisotropic etching of thick silicon wafers
OwnerVladimir Vaganovinventor
Life of this patent
Estimating the term…
Abstract
A method for fabricating semiconductor microstructures with a combination of etching steps, i.e. local RIE, isotropic, etc. followed by deep anisotropic etching.
Claims115
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming at least one opening in said first protective layer;
- c. etching at least one cavity in said silicon wafer through said opening with at least one etching step other than anisotropic etching and with said cavity having at least part of its formed side walls at an angle larger than the minimum angle between {111} crystallographic planes and the surface of the wafer and with the depth of this etching being at least ¼ of the thickness of the wafer;
- and
- d. forming a microstructure with deep anisotropic etching to a depth comparable to the thickness of said silicon wafer.
2 more elements
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming at least one opening in said first protective layer;
- c. etching at least one cavity in said silicon wafer through said opening with at least one etching step other than anisotropic etching and with said cavity having at least part of its formed side walls at an angle larger than the minimum angle between {111} crystallographic planes and the surface of the wafer;
- d. forming a microstructure with deep anisotropic etching;
- e. forming a second protective layer on a side wall and the bottom of said cavity after step c;
- f. removing said second protective layer from the bottom of said cavity;
- and then
- g. conducting step d.
5 more elements
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer, wherein said protective layer contains at least one of the following materials:
- silicon dioxide, silicon nitride, silicon carbide, photoresist, polyimide or metal
- b. forming at least one opening in said first protective layer;
- c. etching at least one cavity in said silicon wafer through said opening with at least one etching step other than anisotropic etching and with said cavity having at least part of its formed side walls at an angle larger than the minimum angle between {111} crystallographic planes and the surface of the wafer;
- d. forming a microstructure with deep anisotropic etching, said microstructure containing at least one through-hole, and wherein said deep anisotropic etching;
- uses an etchant containing at least one of the following etch agents;
- alkali metal hydroxides, tetramethyl-ammonium hydroxide, ethylenediamine, hydrazine, gallic acid;
- and
- is performed in the presence of ultrasonic or megasonic vibrations in the etching solution.
6 more elements
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming at least one opening in said first protective layer;
- c. etching at least one cavity in said silicon wafer through said opening with at least one etching step other than anisotropic etching and with said cavity having at least part of its formed side walls at an angle larger than the minimum angle between {111} crystallographic planes and the surface of the wafer;
- d. forming a microstructure with deep anisotropic etching;
- h. forming a second protective layer on a side wall and bottom of said cavity after stel c.
- i. removing said second protective layer from the bottom of said cavity;
- j. deepening said cavity with an etching step other than anisotropic etching and forming cavity side walls with an angle larger than the minimum angle between {111} planes and the surface of the wafer and then conducting step d.
4 more elements
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming a plurality of openings in said first protective layer;
- c. etching a plurality of cavities in said silicon wafer through said openings with at least one etching step other than anisotropic etching and with said cavities having at least part of their formed side walls at an angle larger than the minimum angle between {111} planes and the surface of said silicon wafer;
- and at least some of said cavities being separated by formed side walls;
- and
- d. forming a microstructure with deep anisotropic etching with at least one of said silicon walls separating adjacent cavities partially etched through to connect at least two of said cavities after said deep anisotropic etching.
3 more elements
Method for fabricating microstructure comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming at least one opening in said first protective layer;
- c. etching at least one cavity in said silicon wafer through said opening with at least one etching step other than anisotropic etching and with said cavity having at least part of its formed side walls at an angle larger than the minimum angle between {111} crystallographic planes and the surface of the wafer;
- d. forming a microstructure with deep anisotropic etching;
- and
- k. an additional step of deposition of a material on the surface of silicon waver;
- said deposition of a material closes the opening in said protective layer.
4 more elements
Method for fabricating microstructures comprising:
- a. forming a first protective layer on a surface of a silicon wafer;
- b. forming a plurality of openings in said first protective layer;
- c. etching a plurality of cavities in said silicon wafer through said openings with at least one etching step other than anisotropic etching and with cavities having at least part of their formed side walls at an angle larger than the minimum angle between planes and the surface of the wafer;
- d. forming a second protective layer on said side walls and on the bottom of said plurality of cavities;
- e. removing said second protective layer from the bottom of at least some cavities;
- f. deepening said plurality of cavities with etching step other than anisotropic with side walls forming with the surface of said silicon wafer an angle larger than the minimum angle between {i11} planes and the surface of the wafer;
- and
- g. forming a microstructure with deep anisotropic etching.
5 more elements
Dependencies are inferred from the claim text.