Methods of and apparatuses for measuring electrical parameters of a plasma process

• US 7,960,670 B2
• Filed: 11/16/2005
• Issued: 06/14/2011
• Est. Priority Date: 05/03/2005
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Beers, Andrew, Freed, Mason L., MacDonald, Paul D., Mundt, Randall S., Spanos, Costas J.
• Primary Examiner(s): Paschall; Mark H
• Application Number:
  US11/281,238
• Publication Number:
  US 20060249729A1
• Time in Patent Office: 2,036 Days
• Field of Search: 219/121.4, 219/121.41, 219/121.43, 219/121.54, 219/121.59
• US Class Current: 219/121.54
• CPC Class Codes: G01K 7/25 for modifying the output characteristic, e.g. linearising
• CPC Class Codes: G01N 27/60 by investigating electrostatic variables , e.g. electrographic flaw testing G01N27/007 takes precedence
• CPC Class Codes: G01N 33/0004 Gaseous mixtures, e.g. polluted air gaseous biological material G01N33/497; exhaust gas of internal combustion engines G01M15/102
• CPC Class Codes: G01R 15/24 using light-modulating devices
• CPC Class Codes: G01R 29/12 Measuring electrostatic fields or voltage-potential
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A sensor apparatus for measuring a plasma process parameter for processing a workpiece. The sensor apparatus includes a base, an information processor supported on or in the base, and at least one sensor supported on or in the base. The at least one sensor includes at least one sensing element configured for measuring an electrical property of a plasma and at least one transducer coupled to the at least one sensing element. The transducer is configured so as to receive a signal from the sensing element and converting the signal into a second signal for input to the information processor.

Claims

1. A sensor apparatus for measuring a plasma process parameter for processing a workpiece, the sensor apparatus comprising:

a base;

an information processor supported on or in the base;

a capacitive sensor supported on or in the base and coupled to the information processor, the sensor having a capacitive sensing element configured so as to provide an output that represents a plasma process parameter measurement, wherein the capacitive sensor is configured to measure an electrical property of a plasma without making direct electrical connection to the plasma, wherein the capacitive sensor includes a transducer coupled to the sensing element, the transducer being configured so as to receive a signal from the sensing element and converting the signal into a second signal for input to the information processor.

2. The sensor apparatus of claim 1 wherein the base comprises a silicon wafer with a diameter of between 100 mm and 450 mm and the sensor apparatus has a thickness of 0.3 mm to 10 mm.

3. The sensor apparatus of claim 1 wherein the base comprises a lithography mask substrate that comprises silica or quartz.

4. The sensor apparatus of claim 1 wherein the base comprises a flat panel display substrate that comprises silica, quartz, glass, or polymer.

5. The sensor apparatus of claim 1 wherein the base comprises a substantially whole semiconductor wafer, a substantially whole flat panel display substrate, or a substantially whole lithography mask.

6. The sensor apparatus of claim 1 comprising a plurality of capacitive sensors having capacitive sensing elements arranged such that the plane of the capacitive sensing elements are substantially parallel with the surface of the base.

7. The sensor apparatus of claim 1 comprising a plurality of capacitive sensors having capacitive sensing elements arranged such that the plane of the capacitive sensing elements are substantially parallel with the surface of the base and the capacitive sensing elements have an area of 0.1 cm² to 10 cm².

8. The apparatus of claim 1 comprising a plurality of capacitive sensors having capacitive sensing elements arranged such that the plane of the capacitive sensing elements are substantially parallel with the surface of the base and the capacitive sensing elements comprising a dielectric polymer having a thickness of 1 micrometer to 100 micrometers.

9. The apparatus of claim 1 comprising a plurality of capacitive sensors having capacitive sensing elements arranged such that the plane of the capacitive sensing elements are substantially parallel with the surface of the base and the capacitive sensing elements comprising a dielectric polymer selected from the group consisting of polyimide, polyester, and polyoly-para-xylylene;

the dielectric polymer having a thickness of 1 micrometer to 100 micrometers.

10. The sensor apparatus of claim 1 wherein the transducer comprises a diode rectification circuit.

11. The sensor apparatus of claim 1 wherein the transducer comprises a diode rectification circuit comprising a semiconductor junction diode for rectifying an applied radio frequency voltage or current and a low pass filter so as to produce a DC voltage or current proportional to the applied RF voltage or current.

12. The sensor apparatus of claim 1, wherein the transducer comprises a power detection circuit that includes:

a resistive load having a resistance between 1 ohm and 1000000 ohms and

a temperature measuring device disposed so as to measure the temperature of the resistive load.

13. The sensor apparatus of claim 1, wherein the transducer comprises a power detection circuit that includes:

a resistive load having a resistance between 1 ohm and 1000000 ohms and

a thermistor or a thermocouple disposed so as to measure the temperature of the resistive load.

14. The sensor apparatus of claim 1, wherein the transducer comprises an optical transducer.

15. The sensor apparatus of claim 1, wherein the transducer comprises an optical transducer comprising a light emitting device configured so as to provide light emissions proportional to the signal from the sensing element and an optical detector configured so as to measure the light emissions from the light emitting device.

16. The sensor apparatus of claim 1, further comprising

a diode rectification transducer coupled to the capacitive sensing element, the transducer being configured so as to receive a signal from the capacitive sensing element and converting the signal into a second signal for input to the information processor.

17. The sensor apparatus of claim 16, wherein the transducer comprises a diode rectification circuit comprising a semiconductor junction diode for rectifying an applied radio frequency voltage or current and a low pass filter so as to produce a DC voltage or current proportional to the applied RF voltage or current.

18. The sensor apparatus of claim 1 wherein the plasma process parameter is radio frequency (RF) field, plasma potential, ion flux, electromagnetic flux such as light, or any process parameter that is affected by the plasma used for the process.