Manufacture of an orifice plate for use in gas calibration

Patent metadata

Field	Value
Publication number	US-10737359-B2
Application number	US-201815948910-A
Country	US
Kind code	B2
Filing date	Apr 9, 2018
Priority date	Apr 9, 2018
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

Methods and systems for preparing a hole having an accurately controlled area in an orifice plate for a mass flow controller are provided. Methods involve forming an initial hole in the orifice plate. The initial hole has an opening having an initial area. The orifice plate comprises a material that can react to form a coating on the orifice plate. The coating occupies a greater volume than the material consumed to form the coating. The material of the orifice plate is reacted with a reactant to produce the coating and thereby produce a reduced area hole having an opening with a reduced area that is smaller than the initial area. The reduced area hole is measured. A determined amount of the coating is removed from at least the reduced area hole to produce a final hole in the orifice plate, wherein the reduced area is smaller than an opening area of the final hole.

First claim

What is claimed is:

1. A method for creating a hole in an orifice plate, the method comprising:
forming an initial hole in the orifice plate comprising a material,
wherein the initial hole has an initial area;

reacting the material of the orifice plate with a reactant to produce a coating and thereby produce a reduced area hole having a reduced area that is smaller than the initial area;
measuring the reduced area hole; and
removing a determined amount of the coating from at least the reduced area hole to produce a final hole in the orifice plate, wherein the reduced area is smaller than an area of the final hole,
wherein the coating occupies a greater volume than the material consumed to form the coating.

2. The method of claim 1 , further comprising installing the orifice plate in a gas box for supplying gases to a semiconductor device fabrication reactor.

3. The method of claim 1 , wherein the material of the orifice plate is selected from the group consisting of: silicon, molybdenum, germanium, and tungsten.

4. The method of claim 1 , wherein the material of the orifice plate is silicon and the coating comprises silicon oxide.

5. The method of claim 1 , wherein forming the initial hole in the orifice plate comprises laser drilling the initial hole in the orifice plate.

6. The method of claim 1 , wherein forming the initial hole in the orifice plate comprises mechanically drilling the initial hole in the orifice plate.

7. The method of claim 1 , wherein the initial area is greater than the area of the final hole.

8. The method of claim 1 , wherein reacting the material of the orifice plate with the reactant comprises performing thermal oxidation of the material of the orifice plate.

9. The method of claim 1 , wherein the material is silicon and the coating is thermally grown silicon dioxide.

10. The method of claim 1 , further comprising:
determining the determined amount of the coating using a difference between the reduced area and a specified area of the final hole.

11. The method of claim 1 , wherein the final hole has a diameter of between about 50 micrometers and 1,800 micrometers.

12. The method of claim 1 , wherein the final hole has a target diameter and wherein the final hole is produced with a variance from the target diameter of no more than about 400 Angstroms.

13. The method of claim 1 , wherein the final hole has a variance from a target diameter of no more than about 250 Angstroms.

14. The method of claim 1 , further comprising:
reacting the orifice plate resulting from (d) to produce a new coating and subsequently repeating operations (c) and (d) on the orifice plate to thereby increase the area of the final hole.

15. The method of claim 1 , wherein removing the determined amount of the coating from at least the reduced area hole comprises conducting a wet etch of the coating.

16. The method of claim 15 , wherein the coating comprises silicon oxide and the wet etch comprises contacting the coating with an aqueous hydrofluoric acid solution.

17. The method of claim 1 , further comprising installing the orifice plate in a flow verification device for mass flow controllers.

18. The method of claim 17 , wherein the material of the orifice plate resists chemical reaction with gases passing through the final hole.

19. The method of claim 18 , wherein the gases are selected from a group consisting of: Ar, BCl 3 , C 2 F 6 , C 2 H 4 , C 4 F 8 , C 4 F 6 , CF 4 , CH 2 F 2 , CH 3 F, Cl 2 , CO, CO 2 , COS, H 2 , HBr, He, N 2 , NF 3 , NH 3 , O 2 , SF 6 , SiCl 4 , SiF 4 , SO 2 , Xe and CF 3 I, and combinations thereof.

Assignees

• Lam Res Corp

Inventors

• Smith Dennis

Classifications

• C23C8/16

  using oxygen-containing compounds, e.g. water, carbon dioxide · CPC title

• B23P15/16 Primary

  plates with holes of very small diameter, e.g. for spinning or burner nozzles · CPC title

• B23B35/00

  Methods for boring or drilling, or for working essentially requiring the use of boring or drilling machines; Use of auxiliary equipment in connection with such methods · CPC title

• C23C8/80

  After-treatment · CPC title

• B23K26/382

  by boring · CPC title