Process for reconditioning semiconductor surface to facilitate bonding

• US 8,956,884 B2
• Filed: 01/26/2011
• Issued: 02/17/2015
• Est. Priority Date: 01/28/2010
• 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: Arunasalam, Parthiban
• Primary Examiner(s): Patel, Reema
• Assistant Examiner(s): GHEYAS, SYED I
• Application Number:
  US13/574,347
• Publication Number:
  US 20120295371A1
• Time in Patent Office: 1,483 Days
• US Class Current: 438/4
• CPC Class Codes: B81C 1/00611 Processes for the planarisation of structures planarising depositions C23C, H01L
• CPC Class Codes: B81C 2201/0121 involving addition of material followed by removal of parts of said material, i.e. subtractive planarization
• CPC Class Codes: B81C 2203/036 Fusion bonding
• CPC Class Codes: H01L 21/02057 Cleaning during device manufacture
• CPC Class Codes: H01L 21/302 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting

Abstract

A non-abrading method to facilitate bonding of semiconductor components, such as silicon wafers, that have micro structural defects in a bonding interface surface. In a preferred method, micro structural defects are removed by forming an oxide layer on the bonding interface surface to a depth below the level of the defect, and then removing the oxide layer to expose a satisfactory surface for bonding, thereby increasing line yield and reducing scrap triggers in fabrication facilities.

Claims

1. A method of reconditioning a surface of a semiconductor device having a micro structural defect, comprising:

a) identifying a micro structural defect in a surface; and

b) utilizing wet chemistry methods to remove material from the surface to a depth below the maximum depth of the micro structural defect.

2. The method of claim 1, where the semiconductor device is made of silicon, and wherein step b) includes the sub-steps:

b1) exposing the surface to liquid nitric acid to grow an oxide layer on the surface; and

b2) removing the oxide layer to reveal a surface substantially free of micro structural defects.

3. The method of claim 2 wherein step b2) includes removing the oxide layer using a wet oxide strip method.

4. A method of reconditioning a surface of a microvalve device, comprising:

a) micromachining a component of a microvalve device from silicon;

b) identifying a micro structural defect in a surface of the component; and

c) utilizing a non-abrading wet chemistry method to remove material from the surface to a depth below the maximum depth of the micro structural defect.

5. The method of claim 4, wherein step c) includes the sub-steps:

c1) applying liquid nitric acid to the surface to grow an oxide layer on the surface below the depth of the micro structural defect; and

c2) removing the oxide layer using a wet oxide strip method to reveal a surface substantially free of micro structural defects.

6. The method of claim 4, Wherein between step b) and step c), the following intermediate steps are performed:

x1) forming a high temperature oxide layer on the surface; and

x2) removing the high temperature oxide layer.

7. A method of fabricating a multi-layer silicon micromachined device, comprising the steps of:

a) micromachining a first layer of a silicon micromachined device, the first layer having a first bonding interface surface;

b) micromachining a second layer of the silicon micromachined device, the second layer having a second bonding interface surface for bonding to the first bonding interface surface;

c) identifying a surface defect in the form of a micro structural defect in at least one of the first bonding interface surface and the second bonding interface surface;

d) utilizing a non-abrading wet chemistry method to remove material from the in at least one of the first bonding interface surface and the second bonding interface surface to a depth below a maximum depth of the micro structural defect and render in at least one of the first bonding interface surface and the second bonding interface surface satisfactory for fusion bonding; and

e) fusion bonding the first bonding interface surface to the second bonding interface surface to join the first layer to the second layer of the multi-layer silicon micromachined device.

8. The method of claim 7, wherein the micromachined device is a silicon microvalve.

9. A method of manufacturing a MEMS device with a moving mechanical component, comprising:

a) micromachining a surface of a component to create a feature, the surface with a feature being a surface of a component part of a MEMS device with a moving mechanical component;

b) identifying a micro structural defect in the surface with a feature;

c) utilizing a non-abrasive wet chemistry method to remove material from the surface to a depth below the maximum depth of the micro structural defect;

d) assembling the component with other components to complete manufacture of the MEMS device with a moving mechanical component.

10. The method of claim 9, wherein the surface was a bond interface surface, and step d) further includes bonding the component to another component of the MEMS device utilizing fusion bonding.

11. The method claim 9, wherein step c) includes utilizing a wet chemistry method to remove material from the surface to a depth below the maximum depth of the micro structural defect.