TW201319298A - Vacuum coating apparatus - Google Patents

Abstract

A vacuum coating apparatus and a method for vacuum coating a substrate are disclosed, having an evacuable coating chamber (12), in which there is provided a substrate carrier (28) for holding a substrate (30) to be coated, having an electrode (24) above the substrate carrier (28), having a counter-electrode (32), and having a gas feed (22) having at least one gas outlet opening (26) for feeding process gases in the direction of the substrate (30). A distance (d) between the substrate carrier (28) and the electrode (24) can be altered. Furthermore, at least one flow guiding element is provided between the electrode (24) and the substrate carrier (28), which flow guiding element can be in the form of a frame which extends from the electrode (24) in the direction of the substrate carrier (28) (Figure 1).

Description

Vacuum coating equipment

The present invention relates to a vacuum coating apparatus having an evacuatable coating chamber in which a substrate carrier is provided for holding a substrate to be coated, and having a substrate on the substrate The electrode above the carrier, having an opposite electrode, and having a gas feed member having at least one gas outlet opening for feeding a process gas in the direction of the substrate.

Such a vacuum coating apparatus is known in principle (for example, U.S. Patent No. 6,626,186 B1). They are used in many coating jobs. This can be, for example, a CVD (Chemical Vapor Deposition) method or a PECVD (plasma enhanced chemical vapor deposition) method. In the latter example, the RF voltage is applied between the electrode and the opposite electrode, with the result that a plasma is produced. Such methods are used, for example, in the fabrication of solar cells, for example to apply a nitride coating to passivate the surface of a solar cell.

One problem with this process is the cleaning operation of the process to apply a non-contaminating coating of a certain thickness to the surface of the substrate which is as uniform as possible. The coating result is hereby influenced by several processing parameters, such as the gas composition of the reaction gas, the temperature of the substrate to be coated, the temperature within the coating chamber, between the electrode and the opposite electrode. Distance, applied voltage or frequency, flow profile of the process gas, and other parameters.

Even if the relevant processing parameters are usually automatically controlled, there are still treatments and uneven coatings that deviate in various ways, which can result in returns.

German Patent No. DE 10 2008 026 000 A1 discloses a vacuum coating apparatus in which a first process gas is introduced into the entire width of a surface of a substrate to be coated in the vacuum chamber, a second treatment Gas is introduced into the vacuum chamber in the region of the narrow side of the substrate, and during coating, the process gas is withdrawn from the narrow side of the substrate by suction.

However, this is only concerned with a method of supporting a vacuum with a different process gas, and does not involve that the coating process is supported by an electric field between an electrode and an opposite electrode. The associated vacuum chamber is designed for a continuous process that uses a coating source in the form of a linear magnetron sputtering source.

In view of this, the present invention is directed to the object of revealing a vacuum coating apparatus in which the coating treatment can be carried out more uniformly and with higher stability than the previous design in a manner substantially free of contamination. Furthermore, an improved vacuum coating process is disclosed which uses a voltage between an electrode and an opposite electrode under the feed of process gas, which allows the process to be performed uniformly and stably.

This object can be achieved in accordance with the invention in the example of the type of vacuum coating apparatus mentioned at the outset, since the distance between the substrate carrier and the oppositely disposed electrode can be varied.

The object of the invention is fully achieved in this way.

In view of the conventional vacuum coating method, the distance between the electrode and the opposite electrode is fixedly defined, and in the vacuum coating method according to the present invention, the substrate carrier is interposed ( Holding the substrate thereon) and The distance between the electrodes is changeable. The coating process can be adjusted to different conditions by varying the distance between the substrate carrier (or opposite electrode) and the electrode. Conditions that are altered during many coating cycles can be considered and the coating process that deviates during this time can be stabilized by varying the distance between the electrode and the opposite electrode.

The vacuum coating apparatus according to the present invention is preferably operated in a batch manner. The mode of operation can be, for example, a PECVD method or a CVD method.

In one development of the invention, a lifting device is provided and the substrate carrier can be moved by the lifting device.

Although it is possible in principle to allow the electrode to be vertically adjusted, in an example in which the substrate carrier is adjusted by a lifting device, an advantageous embodiment is particularly constructed in that the vacuum coating apparatus is constructed to have two A plane in which one of the spaces is disposed above another space and the substrate carrier is movable by the lifting device between the two spaces for reaching in batches in this manner Better yield. Preferably, in this example, the upper space is used for coating, and the space below is used as a temporary storage area for the fully coated substrate and with a suitable handling device to allow for increased throughput.

In an advantageous development of the invention, the distance between the electrode and the substrate carrier is automatically adjusted, preferably by a controller in accordance with at least one coating parameter.

In this way, a process in which the distance between the opposite electrode and the electrode is automatically controlled can be achieved.

The object of the present invention can also be applied to a set by a voltage A method for vacuum coating a substrate between an electrode opposite to a substrate and an opposite electrode and having a processing gas fed to the coating chamber, wherein one is between the electrode and the opposite electrode The distance is set, which is preferably automatically set in accordance with at least one processing parameter.

As mentioned above, this method allows the treatment to be more evenly implemented to have a particularly high quality.

In an advantageous development of the method, the process gas is here fed through a plurality of gas outlet openings in the electrode and guided by the at least one flow guide in the direction of the substrate, suction extraction It preferably occurs in the bottom region of the coating chamber.

Therefore, a particularly uniform processing gas supply from above in the direction of the substrate can be allowed to achieve a particularly uniform coating result.

According to another embodiment of the invention, this object is achieved in an example of the type of vacuum coating apparatus mentioned at the outset, wherein at least one flow guide extends between the electrode and the substrate carrier.

In this way, a particularly homogeneous and uniform substrate coating is provided. Since the flow guide is used between the electrode and the substrate carrier, the processing gas fed from above can be guided particularly uniformly in the direction of the substrate. In this way, the lateral escape of the process gases before they pass through the surface of the substrate can be prevented or minimized.

In a preferred development of the invention, the flow guide is in the form of a frame that extends from the electrode in the direction of the substrate carrier.

Here, the at least one gas outlet opening is preferably disposed in a chamber enclosed by the flow guide.

More preferably, a plurality of gas outlet openings are disposed within the electrode.

Due to this, a very uniform and extensive supply of processing gas from above in the direction of the substrate can be ensured, which results in a very high coating quality.

In a more advantageous configuration of the invention, the flow guide is arranged and dimensioned such that a gap of up to 20 mm, preferably up to 10 mm, more preferably up to 6 mm, is maintained at the base Between the material carrier and the flow guide.

In a more advantageous configuration of the invention, the flow guide is arranged and dimensioned such that a gap of about 2 to 20 mm, preferably about 2 to 7 mm, more preferably about 2 to 5 mm, is Maintained between the substrate carrier and the flow guide.

It has been shown that particularly good coating results can be achieved by this gap size.

In detail, in conjunction with automatically setting the distance between the substrate carrier and the electrode, the remaining gap can be set within the defined range of 2 to 20 mm, so that the optimization of the process can be implemented. Was reached.

In a more advantageous configuration of the invention, the substrate carrier is held on a plate, preferably on a graphite plate, which is joined as the opposite electrode.

In view of the conventional vacuum coating apparatus, the substrate carrier itself is usually connected as the opposite electrode, in the manner of the present invention, the homogenization of the electric field between the substrate and the electrode is due to the use of the board And can be reached. As the opposite electrode, not the substrate itself, but the board, which It is preferably constructed as a graphite plate. In this manner, the substrate is encircled within a more homogeneous electric field between the plate (which has been displaced further downward) and the electrode. A particular benefit is obtained when the board is constructed as a graphite sheet because graphite is an excellent heat conductor and this contributes to a uniform temperature distribution.

In a preferred configuration of the invention, the plate or the graphite plate is heated.

Therefore, particularly uniform heating can be achieved, especially when the board is a graphite sheet. However, in a conventional design, the substrate carrier is heated, and the board on which the substrate carrier is held can be completely heated. Therefore, a more uniform temperature can be ensured. Since the graphite sheet is completely heated, although the cycle time for coating is short, rapid homogenization of the substrate temperature can be achieved in this manner.

In this way, a particularly homogeneous and uniform coating can be supported.

It goes without saying that the above features and the features which will be described hereinafter can be used not only in the combination proposed in each example, but also in other combinations or by themselves without departing from the scope of the invention.

In Fig. 1, a vacuum coating apparatus in accordance with the present invention is generally designated by the numeral 10.

The vacuum coating apparatus 10 has a coating chamber 12 that is surrounded in a gastight manner by a bottom 16, a wall 18 and a top 14. The coating chamber 12 has There is an upper space 38 and a lower space 40 below the upper space. A substrate carrier 28 can be retained in the upper space 38 and the lower space 40. The substrate carrier 28 can be introduced into the upper space 38 and withdrawn from the upper space 38 by a handling device 52 through an associated door 48 on the wall 18. In order to be held in the upper space, the associated roller 36 is used here, which can be actuated from outside the coating chamber 12 by means of a vacuum bushing and which can be moved in the wall by axial movement. 18 was lowered.

In the lower space, there is also provided a transport roller 46 for holding a substrate carrier 28 which can be acted upon by the actuated handling device 54 with the door 50 open. It is fed into or withdrawn from the lower space 40 of the coating chamber 12.

A substrate carrier 28 in the coating chamber 12 is placed flat on a plate 32 when the transfer rollers 36 are retracted into the wall 18, preferably constructed of graphite and It can be moved in a vertical direction with the aid of a lifting device 42. The lifting device 42 includes a lifting drive 64 which may, for example, be an electric cylinder with which a piston can be moved in a controlled manner in a vertical direction with the aid of the lifting drive.

The plate 32 of graphite is heatable, and for this purpose a plurality of heating elements 34 (e.g., resistive heating elements) are disposed on the bottom side of the plate, the heating elements 34 being evenly distributed. It is disposed on the entire bottom side of the board 32. According to FIG. 1, a flat substrate 30 is held on the substrate carrier 28, which can be coated in the coating apparatus 10. The board 32 is connected as an opposite electrode.

Above the substrate 30, an associated flat electrode 24 is placed A distance from the substrate carrier 28. A plurality of gas outlet openings 26 are passed through the electrodes 24, and the gas outlet openings 26 extend over the entire surface of the electrode 24 in a manner that is dispersed in a grid. The gas outlet openings 26 are used to feed a process gas for vacuum coating processing that is fed from the outside of the coating chamber 12 through a connected gas feed member 22.

A voltage is applied between the plate 32 and the electrode 24 (not shown), which may be an RF voltage if the PECVD process is to be performed in the coating chamber under vacuum.

During a coating process, the process gas (as indicated by arrow 74) flows uniformly downwardly in the direction of the substrate 30. A flow guide 70 is provided in order to avoid lateral escape of the process gas and to ensure uniform access of the process gas to the surface of the substrate. The flow guide is a circumferentially closed frame that is secured to the bottom side of the electrode 24 and extends downwardly above the substrate carrier 28.

There is a gap s between the lower end of the flow guide or the frame 70 and the substrate carrier 28, which is preferably in the range of about 2 to 20 mm, especially 2 to 5 mm. Preferably, the spacing is varied with the aid of the lifting device 42 in accordance with at least one processing parameter. To this end, the lifting device 42 is controlled by a central controller 60, as indicated by control line 66. A sensor 62 is purely schematically illustrated in the coating chamber 12, and the sensor 62 is coupled to the central controller 60 via a line 68. The sensor can be, for example, a temperature sensor, a pressure sensor, a sensor for detecting a partial pressure of a particular gas, and the like. Not to be rumored is The sensor 28 is only labeled in a purely schematic manner and can be constructed to form any desired sensor, and can provide several different sensors that are coupled to the central controller 60. In any event, the distance between the substrate carrier 28 and the electrode 24 or the gap s between the lower end of the flow guide or frame 70 and the substrate carrier 28 may be at the controller 60. With the help of one of the parameters, it is set to ensure the optimal implementation of the process.

The coating chamber 12 can be evacuated with the aid of a vacuum pump 20. The vacuum pump 20 has a plurality of suction openings 21 which are preferably arranged in a uniformly distributed manner in the bottom region of the coating chamber 12.

By the flow guide or frame 70, an extremely uniform access of the process gas that is fed through the electrode 24 to the surface of the substrate 30 can be ensured.

The graphite plate 32, which is connected as the opposite electrode, is used to homogenize the electric field because contact with the graphite plate 32 is easier than contact with the substrate carrier 28. Furthermore, graphite is a good thermal conductor which ensures a uniform temperature distribution across the entire surface. An extremely uniform temperature profile can thus be produced across the graphite sheet 32 and thus also on the entire substrate carrier 28 and ultimately on the substrate 30, and this results in a fairly homogeneous coating result.

Since the coating chamber 12 is divided into an upper space 38 and a lower space 40, a particularly rapid yield can be ensured in conjunction with the associated handling device and associated handling and dispensing device.

When the coating process at the upper region 38 of the coating chamber 12 is completed, on the upper portion The substrate carrier 28 on which the substrate 30 is placed can be moved into the lower space 40 by the lifting device 42. When the door 48 or 50 is opened, a new substrate carrier on which the substrate to be coated is placed can be introduced by the handling device 52 as indicated by arrow 56. At the same time, the substrate carrier 28 on which the substrate 30 that has been completely coated is placed can be withdrawn from the lower space 40 by the handling device 54 when the door 50 is opened, as indicated by arrow 58. Marked.

Needless to say, in addition to the two separate doors 48, 50 shown in Figure 1, a common, continuous door or cornice can be provided.

The apparatus preferably operates in a batch mode in a cyclic manner.

2 illustrates the basic structure of a vacuum coating installation, which is generally designated by the numeral 80. According to FIG. 2a), the vacuum coating facility 80 comprises three coating units P1, P2, P3 and a maintenance unit M of identical construction, and a handling unit 82, which are arranged around the outside of a dispensing unit 84. The dispensing unit is in the form of a regular pentagon. The coating units P1, P2, P3 and the service unit M are each coupled to the dispensing unit 84 via an associated port or door.

Each of the coating units P1, P2, P3 and the maintenance unit M are formed by the above-described vacuum coating apparatus 10.

In this example, the same coating process is carried out in all of the coating units P1, P2, P3. Due to the parallel operation of the coating units P1, P2, P3, a high yield can be ensured. The throughput of the coating units P1, P2, P3 is designed such that three coating units are sufficient to ensure a nominal production rate. The repair unit M has such a coating sheet The elements P1, P2, and P3 have the same structure and thus serve as a reserve capacity. This means that the coating operation is performed at a nominal yield, while at the same time maintenance work (eg, cleaning work and the like) can be performed in one unit (within repair unit M) without detracting This nominal output rate.

Fig. 2b) shows a different state of the vacuum coating facility 80', in which the unit previously used as the coating unit P3 in the process of Fig. 2a) is now used as the maintenance unit M, and before The maintenance unit M is now operated in this process as the coating unit P3.

Thus, the number of coating units that can be used is the same as the previous number, while at the same time a different unit of the units is now used for maintenance, which is labeled M.

Fig. 2c) shows another state of the vacuum coating facility 80", in which the unit previously used as the coating unit P2 in Fig. 2b) is now used as the maintenance unit M, while the previous maintenance unit is now It is used as the coating unit P2.

Thus, the nominal yield of the entire vacuum coating facility can be achieved at all times, while one of the units is always offline for maintenance purposes. Overall, this design ensures approximately 97% uptime.

10‧‧‧Vacuum coating equipment

12‧‧‧ Coating Room

14‧‧‧ top

16‧‧‧ bottom

18‧‧‧ wall

38‧‧‧Upper space

40‧‧‧Lower space

28‧‧‧Substrate carrier

30‧‧‧Substrate

48‧‧‧

50‧‧‧

52‧‧‧Transportation device

36‧‧‧Transport roller

32‧‧‧ boards

42‧‧‧ lifting device

64‧‧‧ Lifting drive

34‧‧‧ heating elements

24‧‧‧ electrodes

26‧‧‧ gas outlet opening

22‧‧‧ gas delivery parts

70‧‧‧Guide or frame

74‧‧‧ arrow

60‧‧‧Central controller

62‧‧‧ sensor

66‧‧‧Control line

68‧‧‧ lines

21‧‧‧ suction opening

20‧‧‧vacuum pump

56‧‧‧ arrow

80‧‧‧vacuum coating facilities

80’‧‧‧vacuum coating facility

80”‧‧‧vacuum coating facilities

P1‧‧‧ Coating unit

P2‧‧‧ Coating unit

P3‧‧‧ Coating unit

M‧‧‧Maintenance unit

82‧‧‧Handling unit

84‧‧‧Distribution unit

Other features and advantages of the present invention can be obtained from the following description of the preferred exemplary embodiments of the drawings, wherein FIG. 1 shows the present invention in a highly simplified and schematic illustration. A cross-sectional view of a vacuum coating apparatus; and Figures 2a) to 2c) show a schematic illustration of a vacuum coating facility having three coating units, a service unit and a handling unit in a pentagon manner Arranged around a central distribution unit, where different types of use are shown in Figures a) to c).

10‧‧‧Vacuum coating equipment

12‧‧‧ Coating Room

14‧‧‧ top

16‧‧‧ bottom

18‧‧‧ wall

20‧‧‧vacuum pump

21‧‧‧ suction opening

22‧‧‧ gas delivery parts

24‧‧‧ electrodes

26‧‧‧ gas outlet opening

28‧‧‧Substrate carrier

30‧‧‧Substrate

32‧‧‧ boards

34‧‧‧ heating elements

36‧‧‧Transport roller

38‧‧‧Upper space

40‧‧‧Lower space

42‧‧‧ lifting device

46‧‧‧Transport roller

48, 50‧‧‧

52‧‧‧Transportation device

54‧‧‧Transportation device

56‧‧‧ arrow

58,68‧‧‧ lines

60‧‧‧Central controller

62‧‧‧ sensor

64‧‧‧ Lifting drive

66‧‧‧Control line

70‧‧‧Guide or frame

Room 72‧‧

74‧‧‧ arrow

S‧‧‧ gap

D‧‧‧distance

Claims (13)

A vacuum coating apparatus comprising an evacuatable coating chamber (12), wherein a substrate carrier (28) is provided for holding a substrate (30) to be coated, and a substrate is disposed An electrode (24) above the substrate carrier (28), an opposite electrode (32), and a gas feed member (22) having at least one gas outlet opening (26) for feeding the process gas Entering the coating chamber (12) is characterized by a distance (d) between the substrate carrier (28) and the electrode (24) being changeable. A vacuum coating apparatus according to claim 1, wherein a lifting device (42) is provided, and the substrate carrier (28) can be prepared for movement by the lifting device. The vacuum coating apparatus of claim 1 or 2, wherein a distance (d) between the substrate carrier (28) and the electrode (24) is preferably determined by a controller (60). At least one coating parameter is automatically adjusted. A vacuum coating apparatus according to claim 1, wherein at least one flow guide (70) extends between the electrode (24) and the substrate carrier (28). A vacuum coating apparatus according to claim 4, wherein the flow guide (70) is in the form of a frame extending from the electrode (24) in the direction of the substrate carrier (28). A vacuum coating apparatus according to claim 4, wherein the at least one gas outlet opening (26) is disposed in a chamber (72) surrounded by the flow guide (70). Such as the vacuum coating equipment of claim 6 of the patent scope, A gas outlet opening (26) is provided on the electrode (24). A vacuum coating apparatus according to claim 1, wherein the flow guide (70) is provided and dimensioned such that a gap of at most 20 mm, preferably at most 10 mm, more preferably at most 6 mm ( s) is held between the substrate carrier (28) and the flow guide (70). A vacuum coating apparatus according to claim 8, wherein the flow guide (70) is provided and sized to have a size of about 2 to 20 mm, preferably about 2 to 7 mm, more preferably about 2 to A 5 mm gap (s) is held between the substrate carrier (28) and the flow guide (70). A vacuum coating apparatus according to claim 1, wherein the substrate carrier (28) is held on a board (32), preferably on a graphite board, the board being joined to the opposite electrode . A vacuum coating apparatus according to claim 10, wherein the board (32) is heated. A method of vacuum coating a substrate (30) in which a voltage is applied between an electrode (24) disposed opposite the substrate (30) and an opposite electrode (32). The gas is fed from above, and a distance (d) between the electrode (24) and the opposite electrode (32) is preferably varied in accordance with at least one processing parameter. The method of claim 12, wherein the process gas system is fed through the plurality of gas outlet openings (26) in the electrode (24) and is guided to the substrate by at least one flow guide (70) In the direction of (30), suction extraction preferably occurs in the bottom region of the coating chamber (12).