Process and apparatus for the plasma coating of workpieces with spectral evaluation of the process parameters

• US 20060051520A1
• Filed: 08/30/2005
• Published: 03/09/2006
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Behle, Stephan, Klein, Juergen, Luettringhaus-Henkel, Andreas, Eimann, Peter
• Granted Patent: US 8,397,667 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/515 using pulsed discharges
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01J 37/32972 Spectral analysis

Abstract

The invention provides a process for coating workpieces by plasma-induced chemical vapor deposition, in which a process gas is introduced into a coating chamber and a plasma is ignited by electromagnetic energy in at least one region of the coating chamber which adjoins the workpiece and in which the process gas is present, wherein the coating operation is monitored on the basis of at least one measured spectral parameter of the plasma, and the workpiece is removed in the event of a deviation from a desired range for the parameter.

Claims

1. A process for coating workpieces by plasma-induced chemical vapor deposition, comprising:

introducing a process gas into a coating chamber;

igniting a plasma by electromagnetic energy in at least one region of the coating chamber, the at least one region adjoining a workpiece, and the process gas being present in the at least one region;

monitoring at least one measured spectral parameter of the plasma; and

removing the workpiece in the event of a deviation from a desired range for the at least one measured spectral parameter.

2. The process as claimed in claim 1, wherein monitoring the at least one measured spectral parameter determines whether a leak is present.

3. The process as claimed in claim 1, wherein the workpiece is a container.

4. The process as claimed in claim 3, wherein introducing the process gas comprises introducing the process gas into an interior of the container, and wherein igniting the plasma comprises igniting the plasma in the interior.

5. The process as claimed in claim 3, wherein monitoring the at least one measured spectral parameter comprises monitoring the at least one measured spectral parameter to determine whether the container has a leak.

6. The process as claimed in claim 1, wherein the at least one measured spectral parameter is an intensity of an emission line or an absorption line of nitrogen.

7. The process as claimed in claim 1, wherein introducing the process gas comprises introducing a process gas with a silicon-containing component to deposit a silicon oxide layer.

8. The process as claimed in claim 1, wherein introducing the process gas further comprises depositing a bonding layer, and wherein introducing the process gas comprises depositing a barrier layer on the bonding layer by plasma-induced chemical vapor deposition.

9. The process as claimed in claim 1, wherein igniting the plasma comprises igniting the plasma by pulsed electromagnetic energy introduced into the coating chamber to generate a pulsed plasma.

10. The process as claimed in claim 9, wherein monitoring at least one measured spectral parameter comprises measuring a time profile of an emission of light of an emission line of a constituent of the process gas during a pulse.

11. The process as claimed in claim 10, wherein the process gas is a process gas with a silicon-containing component, and wherein monitoring at least one measured spectral parameter comprises measuring a time profile of an SiO emission line.

12. The process as claimed in claim 10, wherein measuring a time profile comprises counting plasma pulses on a basis of an intensity of an emission line of the plasma.

13. The process as claimed in claim 12, wherein removing the workpiece comprises removing the workpiece if a number of plasma pulses per unit time drops below a threshold value.

14. The process as claimed in claim 12, wherein counting the plasma pulses further comprises counting a number of electromagnetic pulses and comparing a number of plasma pulses with the number of electromagnetic pulses, and wherein removing the workpiece comprises removing the workpiece if a deviation between the number of plasma pulses and the number of electromagnetic pulses exceeds a threshold value.

15. The process as claimed in claim 12, wherein monitoring at least one measured spectral parameter comprises counting a predetermined number of pulses on a basis of an intensity of an emission line.

16. The process as claimed in claim 1, wherein monitoring the at least one measured spectral parameter comprises measuring an intensity of an absorption line.

17. The process as claimed in claim 1, wherein monitoring at least one measured spectral parameter comprises measuring at least one spectral parameter of an absorption spectrum or an emission spectrum of a process waste gas.

18. The process as claimed in claim 1, further comprising controlling at least one further parameter using the at least one measured spectral parameter.

19. The process as claimed in claim 18, wherein the at least one measured spectral parameter or the at least one further parameter is selected from the group consisting of

a composition of the process gas,

a pressure of the process gas,

a power of the electromagnetic energy,

a pulse duration of the electromagnetic energy, and

a duty cycle of the electromagnetic energy.

20. An apparatus for coating workpieces by plasma-induced chemical vapor deposition, comprising:

a coating chamber;

a device for introducing a process gas;

a device for introducing electromagnetic energy into the coating chamber;

a measuring device for measuring at least one spectral parameter of a plasma generated in the process gas by the electromagnetic energy,

a monitoring device to compare the at least one spectral parameter with a desired range, and

a device for removing the workpiece if the at least one spectral parameter deviates from the desired range.

21. The apparatus as claimed in claim 20, wherein the apparatus is usable to internally coat a container.

22. The apparatus as claimed in claim 21, wherein the monitoring device determines whether the container has a leak on the basis of a measurement of the at least one spectral parameter.

23. The apparatus as claimed in claim 20, wherein the measuring device measures an intensity of an emission line or an absorption line of nitrogen.

24. The apparatus as claimed in claim 20, wherein the device for introducing electromagnetic energy comprises a device for supplying pulsed electromagnetic energy.

25. The apparatus as claimed in claim 24, wherein the measuring device measures a time profile of a light emission of an emission line of a constituent of the process gas.

26. The apparatus as claimed in claim 24, wherein the measuring device measures a time profile of an SiO emission line.

27. The apparatus as claimed in claim 24, wherein the measuring device counts plasma pulses on a basis of an intensity of an emission line of the plasma.

28. The apparatus as claimed in claim 27, wherein the monitoring device determines a number of plasma pulses per unit time.

29. The apparatus as claimed in claim 27, wherein the monitoring device compares a number of plasma pulses with a number of electromagnetic pulses.

30. The apparatus as claimed in claim 20, wherein the measuring device measures an intensity of an absorption line.

31. The apparatus as claimed in claim 20, wherein the measuring device measures at least one spectral parameter of an absorption spectrum or an emission spectrum of a process waste gas.

32. The apparatus as claimed in claim 20, further comprising a control device for controlling at least one further parameter using the at least one measured spectral parameter.

33. The apparatus as claimed in claim 32, wherein the at least one measured spectral parameter or the at least one further parameters is selected from the group consisting of

a composition of the process gas,

a pressure of the process gas,

a power of the electromagnetic energy,

a pulse duration of the electromagnetic energy, and

a duty cycle of the electromagnetic energy.

34. A batch of coated workpieces comprising:

at least one workpiece having a coating applied thereto by a plasma-induced chemical vapor deposition process that comprises introducing a process gas into a coating chamber, igniting a plasma by electromagnetic energy in at least one region of the coating chamber, monitoring at least one measured spectral parameter of the plasma, and removing the at least one workpiece in the event of a deviation from a desired range for the at least one measured spectral parameter,

wherein the at least one region adjoins the at least one workpiece, and

wherein the process gas is present in the at least one region.

35. The batch of coated workpieces as claimed in claim 34, wherein the at least one workpiece is a plurality of coated plastic bottles.

36. The batch of coated workpieces as claimed in claim 35, wherein the plurality of coated plastic bottles have a leak rate which is reduced by 90% compared to an uncoated batch of plastic bottles.

37. The batch of coated workpieces as claimed in claim 34, wherein the coating has a variation in a layer thickness between the batch of coated workpieces that is less than or equal to 5%.

38. The batch of coated workpieces as claimed in claim 35, wherein the coated plastic bottles have a leak rate which is reduced by 95% compared to an uncoated batch of plastic bottles.