Capacitive distance sensing in semiconductor processing tools

• US 7,893,697 B2
• Filed: 03/26/2008
• Issued: 02/22/2011
• Est. Priority Date: 02/21/2006
• Status: Expired due to Fees

• Current Assignee: CyberOptics Semiconductor, Inc. (Nordson Corporation)
• Original Assignee: CyberOptics Semiconductor, Inc. (Nordson Corporation)
• Inventors: Gardner, DelRae H., Ramsey, Craig C.
• Primary Examiner(s): Dole; Timothy J
• Application Number:
  US12/055,758
• Publication Number:
  US 20080231291A1
• Time in Patent Office: 1,063 Days
• Field of Search: 324/661, 324/662
• 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 shape of a gap between the sensor while resting on a platen and a showerhead 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 plates, each forming a capacitor with the showerhead having a capacitance that varies with the gap;

measurement circuitry coupled to the controller and to the plurality of capacitive plates, the measurement circuitry measuring a capacitance relative to each capacitive plate and provide indications thereof to the controller;

wherein the controller provides an indication relative to the shape of the gap based, at least in part, upon the measured capacitances; and

wherein at least one capacitive plate is used to measure two different capacitances while resting on the platen.

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

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

4. The sensor of claim 1, wherein the plurality of capacitive plates includes at least three capacitive plates disposed equally about a periphery of the sensor.

5. The sensor of claim 4, wherein the plurality of capacitive plates further includes at least three capacitive plates disposed proximate a center of the sensor.

6. The sensor of claim 5, wherein all capacitive plates have the same area.

7. The sensor of claim 1, wherein the capacitive plates are arranged symmetrically on the surface of the sensor.

8. The sensor of claim 7, wherein all capacitive plates have the same area.

9. The sensor of claim 8, wherein the plurality of capacitive plates include nineteen capacitive plates.

10. The sensor of claim 1, wherein the shape is domed.

11. The sensor of claim 1, wherein the shape is dished.