Method of wet etching vias and articles formed thereby
View Patent ↗A method for forming smooth walled, prismatically-profiled through-wafer vias and articles formed through the method. An etch stop material is provided on a wafer, which may be a <110> silicon wafer. A mask material is provided on the etch stop material and patterned in such a way as to lead to the formation of vias that have at least one pair of opposing side walls that run parallel to a <111> plane in the wafer. A wet etchant, such as potassium hydroxide, is used to etch vias in the wafer. The use of a wet etchant leads to the formation of smooth side walls. This method allows an aspect ratio of height versus width of the vias of greater than 75 to 1.
1. A method for forming prismatically-profiled through-wafer vias, comprising:
applying an etch stop material to a wafer comprised of silicon;
masking the etch stop material;
patterning openings in the etch stop material, wherein said patterning is such that at least two opposing edges of the openings run parallel to a <111> plane within the wafer; and
applying wet etchant to the openings to form prismatically-profiled through-wafer vias.
2. The method of claim 1 , wherein the etch stop material comprises silicon nitride.
3. The method of claim 1 , wherein the etch stop material comprises silicon carbide.
4. The method of claim 1 , wherein said masking comprises providing a shadow mask.
5. The method of claim 1 , wherein said masking comprises providing a layer of photo-resist material on the etch stop material.
6. The method of claim 5 , wherein said patterning comprises developing a portion of the photo-resist material.
7. The method of claim 1 , wherein said patterning comprises lasing openings in the etch stop material.
8. The method of claim 1 , wherein the wet etchant comprises potassium hydroxide.
9. The method of claim 8 , wherein said applying wet etchant comprises dipping the wafer in the potassium hydroxide.
10. The method of claim 1 , wherein said applying wet etchant comprises forming the prismatically-profiled through-wafer vias having smooth side walls and an aspect ratio of height to width of greater than 75 to 1 and less than about 250 to 1.
11. A method for forming prismatically-profiled through-wafer vias, comprising:
applying an etch stop material to a silicon wafer;
masking the etch stop material;
patterning openings in the etch stop material, wherein said patterning is such that at least two opposing edges of the openings run parallel to a <111> plane within the wafer; and
applying a wet etchant comprising potassium hydroxide to the openings to form prismatically-profiled through-wafer vias.
12. The method of claim 11 , wherein the etch stop material comprises silicon nitride.
13. The method of claim 11 , wherein the etch stop material comprises silicon carbide.
14. The method of claim 11 , wherein said masking comprises providing a shadow mask.
15. The method of claim 11 , wherein said masking comprises providing a layer of photo-resist material on the etch stop material.
16. The method of claim 15 , wherein said patterning comprises developing a portion of the photo-resist material.
17. The method of claim 11 , wherein said patterning comprises lasing openings in the etch stop material.
18. The method of claim 11 , wherein said applying wet etchant comprises dipping the wafer in the potassium hydroxide.
19. The method of claim 11 , wherein said applying wet etchant comprises forming the prismatically-profiled through-wafer vias having smooth side walls and an aspect ratio of height to width of greater than 75 to 1 and less than about 250 to 1.