Method and device for the internal plasma treatment of hollow bodies

• US 20090155490A1
• Filed: 08/24/2006
• Published: 06/18/2009
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Hormes, Robert, Lohmeyer, Manfred, Bicker, Matthias
• Granted Patent: US 8,747,962 B2
• Time in Patent Office: Days
• US Class Current: 427/576
• CPC Class Codes: C23C 16/006 characterized by the colour of the layer
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: G10K 1/064 Operating or striking mechanisms therefor
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32394 Treating interior parts of workpieces

Abstract

The invention relates to a method for the plasma treatment of workpieces, particularly workpieces in the form of hollow bodies, in which a treatment zone in a reactor chamber is at least partially evacuated, a process gas is introduced into the treatment zone, particularly into the cavity of the workpiece, and a plasma is ignited by means of injected electromagnetic energy in the process gas introduced into the treatment zone, wherein the process gas flows through the treatment zone between opposite ends of the zone during the plasma treatment.

Claims

1. A method for the plasma treatment of at least one workpiece in the form of a hollow body, the method comprising:

at least partially evacuating a treatment zone in a reactor chamber;

introducing a process gas into the treatment zone; and

igniting a plasma is ignited by means of injected electromagnetic energy in the process gas introduced into the treatment zone,

wherein the process gas flows through the treatment zone between opposite ends of the zone during the plasma treatment, and wherein the workpiece comprises a first cylindrical or quasi-cylindrical surface and a cylindrical or quasi-cylindrical appendage with a smaller diameter and a shorter length and a second cylindrical or quasi-cylindrical surface, the diameter and the height of the appendage being less than the maximum diameter and the height by at least 20%.

3. The method as claimed in claim 1, wherein the plasma treatment is carried out exclusively on the inside of the hollow body.

4. The method as claimed in claim 1, wherein the plasma treatment is carried out exclusively on the outside of the hollow body.

5. The method as claimed in claim 1, wherein the plasma treatment is carried out both on the inside and on the outside of the hollow body, and wherein the plasma treatments on the inside and the outside of the hollow body are different or affect the surfaces in different ways.

6. The method as claimed in claim 1, wherein the workpiece

i) is shaped cylindrically or quasi-cylindrically and has a maximum external diameter of between 1 mm and 50 mm, or

ii) has a maximum internal diameter of between 1 mm and 50 mm, and a wall thickness of from 0.2 mm to 10 mm, or

iii) wherein the workpiece comprises a second cylindrical or quasi-cylindrical appendage with a smaller diameter and a shorter length, which has a narrow, cannula-like internal diameter of between 0.01 and 15 mm, or

iv) has a volume in the range of 0.1-100 ml.

7. The method as claimed in claim 1, wherein the workpiece is shaped cylindrically or quasi-cylindrically with a first cylindrical or quasi-cylindrical surface and comprises a cylindrical or quasi-cylindrical appendage with a second cylindrical or quasi-cylindrical surface, at least one thin layer with a layer thickness D1 being applied on the first cylindrical or quasi-cylindrical surface and the layer being applied with a thickness D2 on the second quasi-cylindrical surface, the relation 0.2≦

D2/D1≦

5 being satisfied for the ratio of the thicknesses D1 and D2.

8. The method as claimed in claim 1, wherein the process gas is put into the treatment zone through at least one cannula, the internal opening diameter of which is between 0.1 and 5.0 mm, and the wall thickness of which is between 0.05 mm and 3.0 mm.

9. The method as claimed in claim 1, wherein the workpiece is evacuated through an opening at a first end and the process gas is introduced through another opening at a second end of the workpiece, which lies opposite the first end, and wherein electromagnetic energy is input in the axial direction.

10. The method as claimed in claim 1, wherein syringe bodies are plasma-treated internally.

11. The method as claimed in claim 10, wherein the cavity of the syringe is evacuated through its plunger opening.

12. The method as claimed in claim 10, wherein the process gas is delivered through the Luer cone of the syringe body.

13. The method as claimed in claim 10, wherein the process gas is delivered through the plunger opening of the syringe body.

14. The method as claimed in claim 1, wherein the plasma treatment comprises at least one of the steps plasma coating, plasma activation, plasma pretreatment, plasma cleaning, plasma immersion, plasma modification, plasma sterilization.

16. The method as claimed in claim 1, wherein the plasma treatment is used to deposit at least one layer which

i) has a barrier effect against gases, or

ii) has a barrier effect against constituents from the workpiece, or wherein

iii) a barrier layer with a chemical barrier effect, or

iv) a scratch protection layer is deposited, or

v) a UV-reflecting or UV-absorbing layer is deposited, or

vi) a coloring layer is deposited, or

vii) a mirroring or blooming layer is deposited.

17. The method as claimed in claim 1, wherein a plastic surface of the workpiece, which contains at least one of the following materials, is treated:

polycyclic hydrocarbons, polycarbonates, polyethylene terephthalate (PET) or PETG, polystyrene, polyethylene, polypropylene and oriented polypropylene (o-PP), or biaxially oriented polypropylene (BOPP), polymethyl methacrylate, PES, polyethylene naphthalate (PEN), SAN, polymers containing fluorine, EVOH, polyamide, PVC, PVDC, PMMI, PA, ABS, MABS, PMP, PES, PSI.

18. The method as claimed in claim 1, wherein a glass, glass-ceramic or ceramic workpiece is plasma-treated.

19. The method as claimed in claim 1, wherein the electromagnetic energy is injected into the cavity by means of electrodes.

20. The method as claimed in claim 1, wherein an axisymmetric flow of the process gas through the cavity of the workpiece is produced, and wherein electromagnetic energy is input in the axial direction.

21. The method as claimed in claim 1, wherein at least one zone of a reactor chamber is at least partially evacuated, a process gas is introduced into the zone and a plasma is generated by means of injected electromagnetic energy in the vicinity of at least a part of the surface of the workpiece in the process gas being introduced, the plasma being ignited by excitation of gas in a space of the device separate from the reactor chamber while the electromagnetic energy for generating the plasma is injected into the process gas being introduced.

22. The method as claimed in claim 21, wherein the plasma is ignited by excitation of gas in a space separate from the reactor chamber while the electromagnetic energy for generating the plasma is injected into the process gas being introduced, and energetic species or radiation are formed during the excitation and the ignition of the plasma is assisted by them.

23. The method as claimed in claim 21, wherein the plasma is ignited in the environment by means of a glow discharge in the separate space, and wherein the glow discharge is ignited by one of the following parameters:

i) a high voltage in the range of 0.1 kV-100 kV

ii) an alternating current with a frequency of 0.2 kHz-100 MHz,

iii) an rms alternating current in the range of 0.01 mA-2A.

24. The method as claimed in claim 1, wherein the electromagnetic energy is delivered through a coaxial cable and process gas is delivered through the inner conductor of the coaxial cable.

25. The method as claimed in claim 1, wherein the electromagnetic energy is injected through a coaxial cable and the treatment zone is evacuated through the coaxial cable.

26. The method as claimed in claim 1, wherein a functional layer is deposited by means of plasma deposition on pharmaceutical packaging.

27. The method as claimed in claim 1, wherein a layer, which contains at least one of the substances SiO_x, SiO_xC_y, SiO_xN_y, SiN_y, TiO_x, Al_xO_yN_z, Al_xN_z, Al_xO_y, C_xH_y, C_xF_y, TiN_x, is deposited by the plasma treatment.

28. The method as claimed in claim 1, wherein a cavity of a workpiece to be treated is filled at least partially with a filler body and the temperature distribution on the workpiece is thereby rendered more uniform during and after the plasma treatment.

2. (canceled)

15. (canceled)

29. A device for the plasma treatment of at least one workpiece in the form of a hollow body, the device comprising:

a reactor chamber,

a treatment zone in the reactor chamber,

an instrument for at least partially evacuating the treatment zone in the reactor chamber,

an instrument for injecting electromagnetic energy into the treatment zone in order to generate a plasma and

an instrument for introducing process gas into the treatment zone,

wherein the instrument for introducing process gas and the instrument for evacuating the treatment zone are arranged so that the process gas flows through the treatment zone between opposite ends of the zone during operation, and wherein the workpiece comprises a first cylindrical or quasi-cylindrical surface and a cylindrical or quasi-cylindrical appendage with a smaller diameter and a shorter length and a second cylindrical or quasi-cylindrical surface, the diameter and the height of the appendage being less than the maximum diameter and the height by at least 20%.

31. The device as claimed in claim 29, wherein the instrument for introducing process gas into the treatment zone comprises at least one cannula, the opening diameter of which is between 0.1 and 5.0 mm and the wall thickness of which is between 0.05 mm and 3.0 mm.

32. The device as claimed in claim 29, wherein the instrument for introducing process gas comprises an instrument for introducing the process gas through a further opening as a second end of the workpiece, which lies opposite the first end.

33. The device as claimed in claim 29 adapted for the internal plasma treatment of syringe bodies.

34. The device as claimed in claim 33, which comprises a connection instrument to connect an evacuation instrument, for at least partially evacuating the cavity of the syringe body, onto the plunger opening of the syringe.

35. The device as claimed in claim 33, which comprises an instrument for introducing the process gas through the Luer cone of the syringe body.

36. The device as claimed in claim 29, which comprises at least one local shield that encloses the workpiece and locally shields zones of the cavity of the workpiece against injected electromagnetic energy.

37. The device as claimed in claim 29, adapted for the external coating of workpieces, having an instrument for at least partially evacuating the surroundings of a workpiece in the reactor chamber.

38. The device as claimed in claim 29, which comprises reactors movable along a transport path, a delivery position for delivering the workpieces to the reactors, an extraction position for extracting the workpieces from the reactors, and an instrument for plasma treatment between the delivery and extraction positions having an instrument for injecting electromagnetic energy into the cavity.

39. The device as claimed in claim 38, wherein the plurality of coating locations respectively comprise separate energy sources for providing electromagnetic energy, as well as separate antechambers which are connected to the coating zones and to a common vacuum generation instrument, and instruments for exciting the process gas, which are respectively connected to separate second energy sources, are respectively arranged in the antechambers.

40. The device as claimed in claim 29, which comprises a shield for the electromagnetic energy to decouple the feed line of the reactor chamber to the evacuation instrument.

41. The device as claimed in claim 29, which comprises an antechamber before the reactor space, the evacuation instrument being connected to the antechamber.

42. The device as claimed in claim 29, having a reactor chamber for receiving a workpiece to be coated, an instrument for at least partially evacuating at least one zone of the reactor chamber, an instrument for injecting electromagnetic energy into the reactor chamber as well as a space separate from the reactor chamber, and an instrument for igniting the plasma in the reactor chamber, the ignition instrument comprising an instrument for exciting gas in the space separate from the reactor chamber.

43. The device as claimed in claim 42, wherein the ignition instrument comprises an instrument for generating a glow discharge in the space separate from the reactor chamber.

44. The device as claimed in claim 43, which comprises a optical monitoring instrument for the glow discharge.

45. The device as claimed in claim 29, wherein the instrument for injecting electromagnetic energy into the reactor chamber comprises a coaxial cable, the coaxial cable comprising an axially extending channel through which the process gas can be delivered.

46. The device as claimed in claim 29, wherein the instrument for injecting electromagnetic energy into the reactor chamber comprises a coaxial cable, the treatment zone being evacuable through the coaxial cable.

47. The device as claimed in claim 46, wherein an ignition instrument is provided for generating a glow discharge in the channel through the inner conductor of the coaxial cable.

48. The device as claimed in claim 29, which comprises a filler body that at least partially fills a cavity of a workpiece.

49. The device as claimed in claim 48, wherein the filler body absorbs or reflects high-frequency electromagnetic energy.

50. The device as claimed in claim 48, wherein the filler body prevents ignition of a plasma in the immediate vicinity of the filled zone.

51. The device as claimed in claim 46, wherein the filler body is integrated into a coaxial inner conductor.

30. (canceled)