Method and device for in situ stress measurement within a thin film upon its deposition on a substrate

• US 5,745,240 A
• Filed: 06/03/1996
• Issued: 04/28/1998
• Est. Priority Date: 05/11/1994
• Status: Expired due to Fees

• Current Assignee: Essilor International Compagnie Generale D Optique (Essilor International SA)
• Original Assignee: Essilor International Compagnie Generale D Optique (Essilor International SA)
• Inventors: Nouvelot, Luc, Frakso, Fatima, Bosmans, Richard
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US08/652,535
• Time in Patent Office: 694 Days
• Field of Search: 356/72, 356/73, 356/381, 356/382, 356/355, 356/357, 356/345, 356/445, 250/560, 156/601, 156/612, 156/626, 156/627, 118/50, 118/50.1, 118/620-640
• US Class Current: 356/632
• CPC Class Codes: C23C 14/54 Controlling or regulating the coating process
• CPC Class Codes: G01L 1/24 by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
• CPC Class Codes: G01L 5/0047 measuring forces due to residual stresses
• CPC Class Codes: G01L 5/008 Force sensors integrated in an article or a dummy workpiece

Abstract

In situ stress measurement is carried out within a thin film upon its deposition on a substrate. The substrate is supported on a rotatable collective holder having a plurality of sites therefor and the thin film is deposited in the course of rotation of the collective holder. An individual holder is provided for carrying a test sample at one of a plurality of sites on the collective holder. A sensor is adapted to measure deformation of the test sample, thereby to determine the stress within the film deposited along the test sample and hence the stress within the film deposited on the substrate.

Claims

1. In a method for the deposition of a thin film on substrates in a processing chamber, the substrates being supported on a rotatable collective holder having a plurality of sites therefor and the thin film being deposited in the course of rotation of the collective holder, further comprising the steps of:

providing an individual holder for carrying a test sample at one of the plurality of sites on the collective holder, and at least part of a sensor adapted to measure deformation of the test sample; and

measuring with the sensor deformation of the thin film deposited on the test sample so as to determine the stress within the film deposited on the test sample and thereby the stress within the film deposited on the substrates.

2. Device for in situ determination of stresses within a thin film deposited on substrates in the course of deposition inside a processing chamber, the device comprising a rotatable collective holder having a plurality of sites for receiving substrates for the deposition of thin film thereon, said rotatable collective holder having a site receiving an individual holder for carrying a test sample on which the thin film is also adapted to be deposited, and said individual holder carrying at least part of a sensor for measuring deformation of the test sample in situ.

3. Device according to claim 2 wherein said sensor is an optical sensor.

4. Device according to claim 3 wherein said individual holder also carries an output portion of a light source for directing a light beam on to the test sample, and said optical sensor is disposed on said at least part of said sensor for detecting displacement of the light beam reflected by the test sample.

5. Device according to claim 4 wherein said light source has an emitter part located outside said processing chamber, said light source output portion comprising a transmission portion connecting said emitter part to said individual holder.

6. Device according to claim 4 wherein the entire said light source is carried by said individual holder, electrical conductor connecting said light source to an electrical power supply disposed outside said processing chamber.

7. Device according to claim 2, wherein said sensor is an electrical sensor.

8. Device according to claim 7 wherein said at least part of said sensor comprises an electrode, said electrode defining with said test sample a differential capacitor, said sensor further comprising capacitance measuring means connected between said electrodes and said test sample.

9. Device according to claim 8 wherein said electrode is adjustably mounted in position on said individual holder for adjusting the distance between said electrode and said test sample.

10. Device according to claim 2 wherein said sensor is a mechanical sensor.

11. Device according to claim 10 wherein said at least part of said sensor comprises a feeler spring-biased against said test sample, said sensor further comprising a measurement head responsive to force applied by said at least part of said sensor to said test sample.

12. Device according to claim 11 wherein said at least part of said sensor is disposed at an end of an elastically deformable blade member carried by said measurement head.

13. Device according to claim 2 wherein said measurement head is adjustably mounted in position on said individual holder for adjusting initial force applied by said at least part of said sensor to said test sample.

14. Device according to claim 2 wherein an XY table carries said at least part of said sensor on said individual holder.

15. Device according to claim 2 wherein the entire said sensor is disposed inside said processing chamber and carried by said individual holder.

16. Device according to claim 2 wherein said test sample comprises a blade member rigidly attached cantilever-fashion at one end to said individual holder and having a free end remote therefrom.

17. Device according to claim 2 wherein said test sample comprises a disk, said individual holder including a shoulder, said disk bearing through gravity alone on said shoulder.

18. Device according to claim 2 wherein said individual holder has a bottom surface, said test sample being disposed below said bottom surface.

19. Device according to claim 2 wherein the entire said sensor is carried by said individual holder, radio transmission means being provided between said sensor and a receiver disposed outside said processing chamber.

20. Device according to claim 19 wherein said radio transmission means includes a transmitter carried by said collective holder, electrical conductors connecting said transmitter to said sensor, a transmit antenna also carried by said collective holder, electrical conductors also connecting said transmit antenna to said transmitter, a receive antenna carried by said processing chamber, electrical conductors connecting said receive antenna to said receiver, the last mentioned electrical conductors extending sealingly through said processing chamber.

21. Device according to claim 19 wherein said transmit antenna is defined by an electrical wire extending circumferentially around a rotation axis of said collective holder and along a great circle thereon, said receive antenna being disposed above said great circle.

22. Device according to claim 19 wherein a processor unit is provided on an input side of said radio transmission means for converting microcurrent(s) of said sensor into a voltage.

23. Device according to claim 22 wherein said processing unit and said transmitter are both disposed in a common sealed casing carried by said collective holder.

24. Device according to claim 22 wherein said sealed casing also contains batteries for supplying power to said radio transmission means.