Capacitive Distance Sensing In Semiconductor Processing Tools

• US 20080231291A1
• Filed: 03/26/2008
• Published: 09/25/2008
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: CyberOptics Semiconductor, Inc. (Nordson Corporation)
• Original Assignee: CyberOptics Semiconductor, Inc. (Nordson Corporation)
• Inventors: Gardner, DelRae H., Ramsey, Craig C.
• Granted Patent: US 7,893,697 B2
• Time in Patent Office: Days
• US Class Current: 324/662
• CPC Class Codes: G01B 7/023 for measuring distance between sensor and object G01B7/082 and G01B7/102 take precedence
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

A sensor for sensing a gap between the sensor and an object of interest within a semiconductor processing chamber is provided. The sensor includes a housing, a power source inside the housing, wireless communication circuitry, a controller, measurement circuitry and a plurality of capacitive plate pairs. The controller and wireless communication circuitry are coupled to each other, and to the power source. The plurality of capacitive plate pairs are configured to form capacitors having a capacitance that varies with the gap. Measurement circuitry is coupled to the controller and to the plurality of capacitive plate pairs. The measurement circuitry is configured to measure the capacitance of the capacitive plate pairs and provide indications thereof to the controller. The controller is configured to provide an indication relative to the gap based, at least in part, upon the measured capacitances.

Claims

1. A sensor for sensing a gap between the sensor and an object of interest within a semiconductor processing chamber, the sensor including:

a housing;

a power source disposed within the housing;

wireless communication circuitry coupled to the power source;

a controller coupled to wireless communication circuitry and to the power source;

a plurality of capacitive plate pairs configured to form capacitors having a capacitance that varies with the gap;

measurement circuitry coupled to the controller and to the plurality of capacitive plate pairs, the measurement circuitry being configured to measure the capacitance of the capacitive plate pairs and provide indications thereof to the controller; and

wherein the controller is configured to provide an indication relative to the gap based, at least in part, upon the measured capacitances.

2. The sensor of claim 1, wherein the object of interest is a showerhead within a semiconductor processing chamber.

3. The sensor of claim 1, wherein the indication is an indication of overall gap between the sensor and the object of interest.

4. The sensor of claim 3, wherein the overall gap is based on a function of the measured capacitances.

5. The sensor of claim 4, wherein the function is an average.

6. The sensor of claim 1, wherein the indication is an indication of relative tilt between the sensor and the object of interest.

7. The sensor of claim 6, wherein the indication is also an indication of shape of the gap.

8. The sensor of claim 1, wherein the indication is an indication of shape of the gap.

9. The sensor of claim 1, wherein the plurality of capacitive plate pairs includes at least three capacitive plate pairs.

10. The sensor of claim 1, wherein each capacitive plate is isolated from all other capacitive plates.