Selective bonding for forming a microvalve

• US 7,803,281 B2
• Filed: 02/15/2005
• Issued: 09/28/2010
• Est. Priority Date: 03/05/2004
• Status: Active Grant

• Current Assignee: Dunan Microstaq, Inc. (Zhejiang Dun'an Artificial Environment Co., Ltd.)
• Original Assignee: Dunan Microstaq, Inc. (Zhejiang Dun'an Artificial Environment Co., Ltd.)
• Inventors: Davies, Brady Reuben
• Primary Examiner(s): Vinh; Lan
• Application Number:
  US10/590,954
• Publication Number:
  US 20070289941A1
• Time in Patent Office: 2,051 Days
• Field of Search: 216/33, 216/34, 216/35, 216/43, 216/67, 216/79
• US Class Current: 216/33
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/48 using adhesives , i.e. using supplementary joining material; solvent bonding
• CPC Class Codes: B29C 66/004 Preventing sticking together, e.g. of some areas of the parts to be joined
• CPC Class Codes: B29C 66/026 Chemical pre-treatments B29C66/028 takes precedence
• CPC Class Codes: B29C 66/5346 said single elements being substantially flat
• CPC Class Codes: B29C 66/54 Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• CPC Class Codes: B29C 66/543 joining more than two hollow-preforms to form said hollow articles
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/73171 Hydrophilicity
• CPC Class Codes: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: B29L 2031/756 Microarticles, nanoarticles
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

A method for forming a micromachined device is disclosed that includes providing a first silicon layer and a second silicon layer. A coating is provided on a first portion of the first layer. The first layer and the second layer are bonded to each other to form a micromachined device, the coating being effective to prevent the coated first portion of the first layer from bonding to the second layer.

Claims

1. A method of fabricating a micromachined device by selectively bonding a plurality of layers of material, comprising:

a) providing a first layer of material;

b) providing a second layer of material;

c) providing a coating on a first portion of the first layer; and

d) bonding the first layer and the second layer to each other to form a micromachined device, the coating being effective to prevent the coated portion from bonding with the second layer.

2. The method defined in claim 1 wherein the coating material is selected from the group consisting of silicon nitride, silicon carbide, polymer film, fluorocarbon film, and a silicon-ceramic material.

3. The method defined in claim 1 wherein the coating material is silicon nitride.

4. The method defined in claim 1 further comprising, following step a), the step:

a1) thinning the first portion of the first layer to reduce the thickness thereof such that when the coating material is applied to the portion in step c), an upper surface of the coating is substantially flush with an adjacent upper surface of the first layer.

5. The method defined in claim 1, in step d), wherein a fusion bonding process is used to bond the first layer to the second layer.

6. The method defined in claim 1, wherein in step d), a direct bonding process is used to bond the first layer to the second layer.

7. The method defined in claim 1 farther comprising, prior to step c), a step:

c′

) masking a second portion of the first layer wherein the second portion comprises an area of the first layer that is not to be coated by the coating.

8. The method defined in claim 1 wherein the coating is applied with a thickness of 10 Angstroms to 100 micrometers.

9. The method defined in claim 1 wherein the second layer has a plurality of mechanical parts formed in, the mechanical parts being movable relative to a stationary portion of the second layer.

10. The method defined in claim 9 wherein, in step c), the coating is provided on the first layer at a position that corresponds to the position of the mechanical parts formed in the second layer, such that when the first layer is positioned adjacent the second layer, the coating portion is adjacent the mechanical parts.

11. The method defined in claim 10 further comprising, following step d), the steps of:

e) providing a third layer of material;

f) providing a coating on a first portion of the third layer; and

g) bonding the third layer to the second layer, wherein the coating on the third layer is effective to prevent the coated portion from bonding with the second layer.

12. The method defined in claim 11 wherein, in step f), the coating is provided on the third layer at a position that corresponds to the position of the mechanical parts formed on the second layer, such that when the third layer is positioned adjacent the second layer, the coating portion is adjacent the mechanical parts.

13. A method of forming a microvalve comprising:

a) providing a plurality of layers of material, including at least a first layer and a second layer, wherein at least the first layer includes a movable microvalve portion that is movable relative to a stationary portion of the first layer;

b) coating a portion of the second layer;

c) positioning the coated portion of the second layer adjacent to the movable microvalve portion of the first layer; and

d) performing a bonding operation to bond the plurality of layers together, wherein the coating prevents the movable microvalve portion of the first layer from bonding with the coated portion of the second layer while an uncoated portion of the second layer bonds to the stationary portion of the first layer.

14. The method defined in claim 13 wherein the coating material is selected from the group consisting of silicon nitride, silicon carbide, polymer film, fluorocarbon film, and a silicon-ceramic material.

15. The method defined in claim 13 wherein the coating material is silicon nitride.

16. The method defined in claim 13 further comprising, following step a), the step:

a1) thinning the first portion of the second layer to reduce the thickness thereof such that when the coating material is applied to the portion in step b), an upper surface of the coating is substantially flush with an adjacent surface of the second layer.

17. The method defined in claim 13 wherein, in step d), a fusion bonding process is used to bond the first layer to the second layer.

18. The method defined in claim 13 wherein, in a step d), a direct bonding process is used to bond the first layer to the second layer.

19. The method defined in claim 13 further comprising, before step b), a step:

b′

) masking a second portion of the second layer wherein the second portion comprises an area of the second layer that is not to be coated by the coating when the coating is applied to the rest of the second layer in step b).

20. The method defined in claim 13 wherein the coating is applied with a thickness of 10 Angstroms to 100 micrometers.

21. The method defined in claim 13 wherein the plurality of layers includes a third layer of material, and further comprising, following step d), the steps of:

e) providing a coating on a portion of the third layer; and

f) bonding the third layer to the first layer, wherein the coating on the third layer is effective to prevent the movable microvalve portion of the first layer from bonding with the coated portion of the third layer while an uncoated portion of the third layer bonds to the stationary portion of the first layer.

22. The method defined in claim 21, during step e), wherein only a portion of the third layer is coated such that the coating is provided on the third layer at a position that corresponds to the position of the movable microvalve portion of the first layer and a portion of the third layer remains uncoated, and further including, after step e), the step:

e1) positioning the third layer adjacent the first layer such that the coating portion is adjacent the movable microvalve portion of the first layer.

23. A method of selectively bonding a plurality of layers of material to form a micromachined device, comprising:

a) providing a first layer of material;

b) providing a second layer of material;

c) providing a coating on a portion of the first layer of material;

d) etching the first layer of material to form a portion of a micromachined device including a slider portion within the first layer and a fixed portion within the first layer, wherein the slider portion is movable relative to the fixed portion, and the slider portion substantially corresponds to the size and shape of the coated portion; and

e) bonding the first layer and the second layer to each other, the coating being effective to prevent the slider portion of the first layer from bonding with the second layer.

24. The method defined in claim 23 wherein the coating material is selected from the group consisting of silicon nitride, silicon carbide, polymer film, fluorocarbon film, and a silicon-ceramic material.

25. The method defined in claim 23 wherein the coating is applied with a thickness of 10 Angstroms to 100 micrometers.