DEVICE AND METHOD FOR COATING CONTAINERS

Description

[0001] The invention relates to a device for coating containers having the features of the preamble of claim 1. Furthermore, the invention relates to a method for coating containers having the features of the preamble of claim 6.

[0002] Such a device and method are known, for example, from US 2018 / 0363141 A1. A provided process gas is introduced into a process chamber designed as a plasma chamber, in which a container to be coated is located. This plasma-like process gas located in the process chamber is ignited and thus deposited on the container. To ignite the plasma-like process gas, a solid-state generator is used - in contrast to the magnetrons typically used. The energy required for ignition of the solid-state generator is introduced into the process chamber via an antenna that projects into the process chamber and is connected to the solid-state generator via a coaxial cable. The solid-state generator is controlled by a controller that receives the required data from a sensor arranged in the process chamber.Within the process chamber there is a microwave-permeable quartz cylinder that surrounds the container to be coated and shields it liquid-tight from the space in which the antenna of the solid-state generator is located.

[0003] WO 03 / 100125 A1 discloses arranging a plurality of plasma chambers on a rotating wheel. This supports a high production rate of containers per unit of time. Furthermore, double or multiple chambers can also be used as plasma chambers.

[0004] An object of the present invention is to provide an apparatus and a method for coating containers in which a simplified construction of the apparatus is used.

[0005] This object is achieved for the generic device and for the generic method by the characterizing features of the respective independent claim. Advantageous developments of the device and method according to the invention are recited in the dependent claims.

[0006] Because the invention provides a microwave generator in the form of a solid-state generator instead of a magnetron, which ignites and maintains the plasma in the plasma chamber, improved plasma deposition on the inner wall of the vessel is achieved, resulting in improved reliability and process control. The fact that there is no sensor in the plasma chamber to control the microwave generator and no monitor diode to detect the current power simplifies the design and control of the microwave generator.

[0007] Solid-state generators and their use in plasma generation are described, for example, in Louis Latrasse et al.: "2.45-GHz microwave plasma sources using solid-state microwave generators. Collisional-type plasma source", JOURNAL OF MICROWAVE POWER AND ELECTROMAGNETIC ENERGY, Vol. 51, No. 1, January 2, 2017 (2017-01-02), pages 43-58, XP055564796, US ISSN: 0832-7823, DOI: 10.1080 / 08327823.2017.1293589.

[0008] According to the invention, the at least one microwave generator is directly connected to the at least one plasma chamber via a quartz disk arranged at the point of introduction. This eliminates the need for a component, usually a waveguide, compared to the use of a magnetron, and furthermore, an isolauncher for coupling the magnetron is no longer required.

[0009] Advantageously, the inlet location can be located in the process gas line inlet area, on the surface of the at least one plasma chamber opposite this area, and / or in a side area of ​​the at least one plasma chamber. These locations are particularly suitable for ensuring proper functionality.

[0010] Advantageously, the inlet location can be located in the process gas line inlet area, axially opposite a gas lance outlet. This allows the gas lance to be used as an antenna, eliminating the need for coupling via a complex quartz glass. Furthermore, targeted excitation of desired modes is possible by changing the length of the gas lance.

[0011] Advantageously, the device can comprise a cooling device integrated into a reactor block, wherein the solid-state amplifier of the at least one solid-state generator is detachably connected to the reactor block. This eliminates the need to work on the cooling circuit when replacing the solid-state amplifier.

[0012] Advantageously, exactly one solid-state amplifier and / or exactly one control unit and / or exactly one signal generator and / or exactly one power supply can be present. This allows components to be saved in devices with multiple plasma chambers.

[0013] Because the plasma is generated in the method according to the invention without sensor detection of the input energy quantity and without control of the microwave generator, sensors in the plasma chamber for detecting the input energy quantity can be dispensed with, which leads to a simplification of the coating device. A further simplification of the coating device is achieved by not controlling the microwave generator depending on the field configuration.

[0014] Advantageously, the method can be carried out in a device according to the invention. This results in the advantages stated above for the respective embodiments of the device according to the invention.

[0015] Advantageously, the field configuration within the plasma chamber can be influenced by synchronized control of at least two microwave generators connected to the plasma chamber. This allows the field configuration within the plasma chamber to be influenced and, for example, field inhomogeneities to be compensated.

[0016] It is understood that the features and embodiments explained above and below are not only disclosed in the respective combinations specified, but are also to be considered as belonging to the disclosure in isolation and in other combinations.

[0017] The invention will be explained in more detail below using a preferred embodiment with reference to the drawings. The drawings show: Figure 1 is a schematic diagram of a first embodiment of a device which has a waveguide in a manner not according to the invention; Figure 1a is a schematic diagram as Figure 1with details, wherein a waveguide is provided in a manner not according to the invention, Figure 2a schematic diagram of a second embodiment of a device according to the invention, Figure 2aa schematic diagram such as Figure 2 with details, Figure 3 a schematic diagram of a third embodiment of a device according to the invention, Figure 3a a schematic diagram as Figure 3 with details, Figure 4 is a schematic block diagram of a preferred embodiment of a device according to the invention, Figure 4a is a schematic block diagram as Figure 4 , Figure 5 is a schematic block diagram of a further preferred embodiment of a device according to the invention, which has a waveguide in a manner not according to the invention, and Figure 5a is a schematic block diagram as Figure 5 with details.

[0018] In the Figures 1, 1a , 2, 2a , 3 and 3aThree embodiments are shown schematically to explain the invention, in which a plasma station 15 (see Figures 4, 4a ) has exactly one plasma chamber 8 with exactly one treatment station for a container 9, which has a container interior 11, with associated device features. However, the invention also covers devices with more than one plasma chamber 8 and also plasma chambers 8 that have more than one treatment station. If there are several plasma chambers 8, they are usually arranged on a rotating (not shown) plasma wheel, as is known, for example, from the above-mentioned WO 2017 / 102280 A2. However, the invention is not limited to a rotating plasma wheel, but in particular includes all rotating or non-rotating coating machines that have one or more process steps with fixed process gas mixtures and continuous process gas consumption.

[0019] In the first embodiment of the Figure 1 the container 9 to be coated is already arranged in its receiving device in a reactor chamber 10 of the plasma chamber 8 and a gas lance 12 is introduced into the container interior 11 from below through the opening of the container 9.

[0020] The containers 9 to be coated are fed to the plasma station 15 using known devices and following known methods. The plasma chamber 8 has a vacuum line 14 connected to a vacuum unit (not shown) that reduces the pressure in the reactor chamber 10 in order to draw a process gas provided by a process gas generator (not shown) into the container 9 via a process gas line (not shown) that opens into the lower end of the gas lance 12. This process gas is used to coat the inner wall of the container 9. The coating is also carried out using known methods. The difference from the previously known methods lies in the use of an alternative microwave generator 1 in the form of a solid-state generator 1.Although such solid-state generators 1 have recently been used in principle according to the above-mentioned prior art, the invention dispenses with device parts compared to the known devices and methods, as will be explained further below.

[0021] In the plasma chamber 8, the container 9 is inserted and positioned in a gas-tight and / or airtight manner in the reactor chamber 10. A chamber base 23 has a vacuum line 14. This opens into the plasma chamber 8 from below or, depending on the position of the gas lance 12, also establishes a gas-permeable connection to the container interior 11. In particular, it can be provided that when the gas lance 12 is retracted into the container interior 11, the container interior 11 is insulated, i.e., sealed, from the reactor chamber 10, whereas when the gas lance 12 is lowered, a gas-permeable connection is created between the container interior 11 and the reactor chamber 10. Additional vacuum lines (not shown) and at least one ventilation line (not shown) can also be connected.The gas lance 12 can be coupled via the (central) process gas line to further process gas lines (not shown), via which different process gas compositions can be supplied to the container interior 11 by means of the gas lance 12.

[0022] A typical treatment process at the plasma station 15 is briefly explained below using the example of a coating process: First, the container 9 is transported to the plasma wheel using an input wheel (not shown), and with a sleeve-like chamber wall pushed up, the container 9 is inserted into the corresponding plasma chamber 8. After completion of the insertion process, the respective chamber wall at this plasma station 15 is lowered into its sealed position, and initially, an evacuation of both the reactor chamber 10 and the container interior 11 is carried out simultaneously.

[0023] After sufficient evacuation of the reactor chamber 10, the gas lance 12 is retracted into the vessel interior 11, and by moving a sealing element, the vessel interior 11 is sealed from the reactor chamber 10. The pressure in the vessel interior 11 can then be further reduced. Once a sufficiently low negative pressure has been reached, process gas is introduced via the gas lance 12 into the vessel interior 11 of the vessel 9 at the corresponding plasma station 15. After sufficient process gas has been supplied, the microwave generator 1 ignites the plasma in the vessel interior 11. To facilitate ignition, an ignition aid 13 is provided in the chamber base 23. The ignition aid 13 projects into the vacuum line 14 opposite the gas lance 12.In particular, it can be provided that with the aid of the plasma both an adhesion promoter on the surface of the container interior 11 and the actual barrier and protective layer are deposited.

[0024] The microwave generator 1 is a solid-state generator 1 - the design of which is described in more detail below in connection with the Figures 4 and 5described - is used, which is connected to the reactor chamber 10 of the plasma chamber 8 via a waveguide 5 not provided according to the invention and whose opening into the reactor chamber 10 is sealed gas-tight by a quartz disk 7. An optical emission spectroscope 6 is arranged within the waveguide 5, with which the process is monitored and it is ensured that the pulses emitted by the solid-state generator 1 can also be detected in the plasma. The intensity of the pulses is detected and a summation of all pulse intensities is carried out. This results in an evaluation basis which serves as a comparison to a target value defined in a recipe. This can be used to detect, for example, incorrect gas compositions and pressures. The optical emission spectroscope 6 is only used for monitoring, but not for control.

[0025] According to the invention, in contrast to the prior art, no sensors for controlling the solid-state generator 1 are present on and in the reactor chamber 8. The control of the solid-state generator 1 is described in more detail below in connection with the Figures 4 and 5 described.

[0026] After completion of the plasma treatment, the container interior 11 is ventilated to atmospheric pressure. Simultaneously, the gas lance 12 can be lowered from the container interior 11. After sufficient ventilation of the container interior 11 and the plasma chamber 8, preferably to atmospheric pressure or ambient pressure, the chamber wall is raised again. The coated container 9 is then removed or transferred to a discharge wheel (not shown).

[0027] In Figure 1a are some details of the first embodiment of the Figure 1 In principle, all the above-mentioned Figure 1statements also apply to Figure 1a . In addition, the following details can be seen.

[0028] The gas lance 12 is funnel-shaped at its upper end to prevent clogging with deposits. The neck of the container 9 forms a gas-tight seal with the vacuum line 14, so that the ignition aid 13 is connected to the interior 11 of the container 9 via the vacuum line 14 into which it extends, and can thus more effectively ignite the plasma located in the interior 11 of the container. The quartz disk 7 closes an opening of the plasma chamber 8 and does not flush with the inner wall of the plasma chamber 8, but rather recesses slightly. The optical emission spectroscope 6, which is arranged within the waveguide 5 (not provided according to the invention), is enclosed by an antenna element 25, through which energy is introduced into the plasma to enable ignition.

[0029] The second embodiment, which is shown in Figure 2 shown, differs from the first embodiment of the Figure 1 in that the solid-state generator 1, 1' is not connected to the reactor chamber 8 via a waveguide 5, but is mounted directly on the wall of the plasma chamber 8. In Figure 2 Two positions are shown in which the solid-state generator 1, 1' can be arranged. In its first position, the solid-state generator 1 couples its energy into the reactor chamber 10 at the same location as in the first embodiment of the Figure 1 , namely on the upper surface opposite the gas lance 12. Here, too, a quartz disk 7 for the gas-tight sealing of the solid-state generator 1 from the reactor chamber 10 and an optical emission spectroscope 7 are present.

[0030] Alternatively or additionally, another solid-state generator 1' can be attached to the plasma chamber 8. This is arranged on the side wall of the plasma chamber 8 and couples its energy into the reactor chamber 10 via another quartz disc 7'.

[0031] If two solid-state generators 1, 1' are used, the field constellation within the reactor chamber 10 can be influenced by a suitable synchronous control of these two solid-state generators 1, 1' in such a way that the best possible deposition result of the process gas on the surface of the vessel interior 11 is achieved.

[0032] In Figure 2a are some details of the second embodiment of the Figure 2 In principle, all the above-mentioned Figure 2 statements also apply to Figure 2a . In addition, the following details can be seen.

[0033] The gas lance 12 is funnel-shaped at its upper end to prevent it from becoming clogged with deposits. The neck of the container 9 forms a gas-tight seal with the vacuum line 14, so that the ignition aid 13 is connected to the interior 11 of the container 9 via the vacuum line 14, into which it extends, and can thus more effectively ignite the plasma located in the interior 11 of the container. The quartz disk 7 in the alternative closes an opening of the plasma chamber 8 and does not fit flush with the inner wall of the plasma chamber 8, but rather recesses slightly. The optical emission spectroscope 6 is arranged behind the quartz disk 7, as viewed from the reactor chamber 10. In the upper region of the plasma chamber 8, an antenna element 25, which is assigned to a connected solid-state generator 1, projects into the reactor chamber 10.In the alternative arrangement of the solid-state generator 1' on the left of the plasma chamber 8 - instead of the alternative in which the solid-state generator 1 is arranged on top of the plasma chamber 8 - the antenna element 25' connected to it (shown in dashed lines) projects into the reactor chamber 10 instead of the antenna element 25 shown above, through which energy is introduced into the plasma in order to enable ignition.

[0034] The third embodiment of the Figure 3 is the one who Figure 2very similar. It differs essentially in that a single solid-state generator 1" is arranged below the chamber base 23. It feeds its energy not directly via the wall of the plasma chamber 8 into its reactor chamber 10, but via the vacuum line 14, with a quartz disk 7" ensuring a gas-tight seal to this and thus also to the reactor chamber 10. In terms of its orientation, the quartz disk 7" lies axially opposite the outlet of the gas lance 12 and - as in the other embodiments - an optical emission spectroscope is present in the area of ​​the quartz disk 7".

[0035] In Figure 3a are some details of the third embodiment of the Figure 3 In principle, all the above-mentioned Figure 3 statements also apply to Figure 2a . In addition, the following details can be seen.

[0036] The gas lance 12 is funnel-shaped at its upper end to prevent clogging with deposits. The neck of the container 9 forms a gas-tight seal with the vacuum line 14, so that the ignition aid 13 is connected to the interior 11 of the container 9 via the vacuum line 14 into which it extends, and can thus more effectively ignite the plasma contained in the interior 11 of the container. The quartz disk 7 in the side wall of the plasma chamber 8 is not flush with its interior wall, but rather recesses slightly. The optical emission spectroscope 6 is arranged behind the quartz disk 7, as viewed from the reactor chamber 10. In the lower area of ​​the vacuum line 14, the antenna element 25, which is associated with a solid-state generator 1" connected thereto, projects into an anteroom communicating with the interior 11 of the container 9. The lower end of the gas lance 12 is, unlike in the Figures 1, 1a , 2 and 2aformed, since the solid-state generator 1" blocks the linear continuation of the gas lance 12 and the vacuum line 14. It can be seen that the gas lance 12 is connected to a horizontally running process gas supply line 26. Parallel to this, a vacuum connection 27 running underneath and connected to the vacuum line 14 is provided, which serves to establish the process gas pressure. Via this connection, gas is discharged from the reactor chamber 10 before coating, and after the coating of the container 9 has been completed, the gas still present in the reactor chamber is discharged.

[0037] Figure 4 shows a schematic representation of how the solid-state generator 1 is basically constructed and connected to the reactor chamber 10.

[0038] The solid-state generator 1 has an RF amplifier 2 (also referred to as solid-state amplifier 2), which receives an input power P in from a signal generator 3, which is specified via control signals arriving from the left. By means of the RF amplifier 2, which is fed by a power supply 4 with a gain factor G (Vs) depending on the supply voltage of the transistors, this input power P in is amplified and thus fed as output power P out into the reactor space 10 of the plasma chamber 10, which is located in the plasma station 15, in order to ignite the plasma present there, as described above. Figure 1 described. By changing the voltage, the output power of solid-state generator 1 can be controlled.

[0039] In Figure 4a is an abstract representation of the schematic block diagram of the Figure 4 , in which the text elements are also omitted. Thus, all the above-mentioned Figure 4statements also apply to Figure 4a The leftmost line carries the control signals; between signal generator 3 and RF amplifier 2, the input power P in is amplified, and between RF amplifier 2, the output power P out is fed into reactor chamber 10; furthermore, RF amplifier 2 is fed by power supply 4 with a gain factor G.

[0040] In Figure 5 Another schematic embodiment of a solid-state generator 1 is shown. This is connected to the waveguide 5, which is not provided according to the invention, via a connecting flange 16. The waveguide 5 is sealed gas-tight with the reactor chamber 10 via the quartz disc 7.

[0041] The solid-state generator 1 has a solid-state amplifier 2, which has three main transistors 22 on each side (there may be more or fewer depending on the desired power), which receive their input power from a power supply 4. The power supply 4 receives its control signal from an input transistor 21, which serves as a preamplifier.

[0042] The input transistor 21 of the solid-state generator 1 is powered by a signal generator 3, which supplies the input power for the solid-state generator 1 and is not a component thereof. The signal generator 3 is in turn connected to an external power supply 4'. Alternatively, the signal generator 3 can also be a component of the solid-state generator 1 and be powered by an external power supply.

[0043] The output signal of the solid-state amplifier 2 reaches a circulator 18, which provides the energy required to ignite and maintain the plasma in the reactor chamber 10. The circulator 18 transmits the energy via the coupling into the reactor chamber 10. In the illustrated embodiment, the energy input 19 occurs via the waveguide 5; however, this can also be achieved using other antenna concepts. The power is directed in the circulator 18. To control the energy input 19, the solid-state generator 1 has an incoming and an outgoing sensor connection 19, which are connected to a corresponding sensor, for example in the form of a monitor diode (which has no connection to the plasma chamber 8).What is important in connection with the invention is that, in contrast to the prior art, for example the above-mentioned US 2018 / 0363141 A1, no sensor is used to detect conditions within the reactor chamber 10, and the solid-state amplifier 1 also does not receive any information about the current power of the energy input 19 from the reactor chamber 10. Rather, the incoming power (wave) is detected by the sensor connection 17 shown above, and the returning power (wave) is detected by the sensor connection 17 shown below. The sensor connections 17 only monitor whether the desired power is coming out of the circulator 18. To absorb the wrongly directed power from the circulator 18, an absorption element is provided, which can be designed, for example, as a water bag or resistor.

[0044] The following are specifications regarding the components used and their characteristics. These are merely examples and do not limit the invention in any way.

[0045] The main transistors 22 are LD MOS rectifiers with a power output of 250-330 W (possibly mirrored, so that a total of six such main transistors 22 are present), and the input transistor 21 has a power output of 20-150 W, ideally 25-100 W. The internal power supply 4 must be variable and has a voltage of 40-60 V DC, whereas the external power supply 4' has a voltage of only 5-12 V. The circulator 18 delivers a power of approximately 2 kW over the range of 1-5 kW, ideally 1.5-4 kW, into the reactor chamber 10. The external power supply 4' supplies a voltage of 5-12 V. The signal generator 3 is a VCO or PLL operating at its natural frequency, with an RF switch for pulsing, for example an excited quartz crystal. It has a power in the range of 0.5-15 mW, in particular approximately 1 mW.

[0046] In Figure 5aSome details of the connection of the solid-state generator 1 with the plasma chamber 8 can be seen, which have minor modifications compared to the embodiment shown in Figure 5. In principle, all statements made above regarding Figure 5 also apply to Figure 5a .

[0047] The following changes have been made: The connection flange 16 of the solid-state generator 1 is connected to a connection of the waveguide 5, which is not provided according to the invention; this is attached at its other end via another connection to the plasma chamber 8. In addition, the quartz disc 7 of the Figure 5 which is not necessary since no optical measurement via an optical emission spectroscope 6, as in the embodiments of the Figures 1, 1a , 2, 2a , 3 and 3aThe distance between the connection flange and the housing of the solid-state generator 1 does not result in any technical changes. The arrow representing the energy input 19 was also pointed out as shown in Figure 5 omitted; the energy input 19 is the same as in Figure 5 executed.

[0048] The invention has been described above using exemplary embodiments. It is understood that numerous changes and modifications are possible without departing from the inventive concept underlying the invention. The invention is defined by the claims.

Claims

1. Device for coating containers (9) by means of a plasma method, comprising at least one plasma station (15) that comprises at least one plasma chamber (8) with at least one treatment station with a container holder, in which at least one container (9) with a container interior (11) can be used and positioned at the treatment station, wherein the respective plasma chamber (8) comprises a vacuum line (14) connected to a vacuum unit, by means of which it can be at least partially evacuated, wherein the respective plasma chamber (8) comprises a gas lance (12) which can be inserted into the container interior (11), wherein the gas lance (12) is connected to a process-gas line, via which a process gas provided by a process gas generator enters the container interior (11) for its coating, wherein the respective plasma chamber (8) is connected to at least one microwave generator (1, 1', 1") and the microwave generator (1, 1', 1") comprises a control unit, a signal generator (3) and a power supply (4, 4'), the at least one microwave generator (1, 1', 1") is a solid-state generator comprising a solid-state amplifier (2), characterized in that, in the at least one plasma chamber (8), there is no sensor for controlling the microwave generator (1, 1', 1") and no monitor diode for sensing its current power level, wherein the at least one microwave generator (1, 1', 1") is directly connected to at least one plasma chamber (8) by means of a quartz disc (7, 7', 7") arranged at the point of introduction.

2. The device according to Claim 1, wherein the point of introduction is located in the region of the process-gas line's introduction, on the surface of at least one plasma chamber (8) opposite this region and / or in a lateral region of at least one plasma chamber (8).

3. The device according to claim 2, wherein the point of introduction is located in the region of the process-gas line's introduction in the axial direction opposite to an outlet of the gas lance (12).

4. The device according to any one of the Claims 1 to 3 comprising a cooling device integrated in a reactor block, wherein the solid-state amplifier (2) of at least one solid-state generator (1, 1', 1") is connected to the reactor block in a detachable manner.

5. The device according to any one of the Claims 1 to 4, wherein exactly one solid-state amplifier (2) and / or exactly one control unit and / or exactly one signal generator (3) and / or one power supply (4) is / are present.

6. A method for coating containers (9) in a device for coating containers (9) by means of a plasma process, comprising the following process steps: - inserting and positioning of a container (9) with a container interior (11) at a treatment station of a plasma chamber (8) of a plasma station (15), - at least partially evacuating the respective plasma chamber (8) in order to aspire a process gas provided by a process gas generator into the container (9), - coating of the tank interior (11) by means of plasma treatment, - producing plasma from the process gas by means of a microwave generator (1, 1', 1") in the form of a solid-state generator, characterized in that - the generation of the plasma takes place without sensor detection of the input amount of energy in the plasma chamber (8) and no control of the microwave generator (1, 1', 1") is carried out depending on the field constellation, wherein the at least one microwave generator (1, 1', 1") is directly connected to at least one plasma chamber (8) by means of a quartz disc (7, 7', 7") arranged at the point of introduction.

7. The method of claim 6, wherein it is carried out in an device according to any one of the Claims 1 to 5.

8. The method according to any one of the Claims 6 or 7, wherein the field constellation within the plasma chamber (8) is influenced by the synchronized control of at least two microwave generators (1, 1', 1") connected to the plasma chamber (8).