TW201327618A - Vacuum coating apparatus - Google Patents

Abstract

A vacuum coating apparatus is disclosed having an evacuable coating chamber (12), wherein there is provided a substrate carrier (28) for holding a substrate (30) to be coated, having an electrode (24) above the substrate (30) to be coated, and having a counter-electrode (32) wherein the substrate carrier (28) is held on a plate (32) which preferably consists of graphite and which is connected as the counter-electrode.

Description

Vacuum coating equipment

The present invention relates to a vacuum coating apparatus having an evacuatable coating chamber in which a substrate carrier for holding a substrate to be coated is provided, having The electrode above the substrate to be coated has an opposite electrode.

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.

In contrast to the background of the invention, the invention has been developed for the purpose of improving the type of vacuum coating apparatus mentioned at the outset, wherein the coating treatment can be carried out as uniformly as possible and with high stability. Furthermore, an improved vacuum coating method for applying a voltage between an electrode and an opposite electrode under the application of a process gas is proposed which allows the coating process to be carried out as uniformly and stably as possible.

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 substrate carrier is held on a board which is joined as the counter electrode and preferably by Made up of graphite.

The object of the invention can be achieved in this way.

In view of the conventional vacuum coating apparatus, a substrate to be coated (for example, a wafer) is directly placed on a substrate carrier made of carbon fiber (CFC) and connected as an opposite electrode. According to the invention, the substrate carrier is held on a board which is joined as the opposite electrode. Thus, the substrate is held in a more homogeneous electric field because the electric field extends as far as the board. In this way, a more homogeneous coating result can be obtained.

In a preferred development of the invention, the panel is constructed of graphite. Compared to metal substrate carriers, graphite is a better thermal conductor and therefore contributes to a homogeneous temperature distribution and contributes to better coating.

Due to the weight of the board and its large surface area, the board is preferably comprised of a plurality of individual panels.

In a preferred configuration of the invention, the board is heated. In detail, when the board is made of graphite, due to its good thermal conductivity Therefore, a particularly homogeneous temperature distribution can be achieved and a more homogeneous coating result can be achieved.

In view of the conventional apparatus, the substrate carrier is indirectly heated, and the board on which the substrate carrier is held can be heated locally. Therefore, a more uniform temperature can be ensured.

For heating, a plurality of heating elements (e.g., heating elements in the form of resistive heating elements) are preferably disposed beneath the board. The heating elements are preferably spread as evenly as possible over the entire surface of the panel to achieve a particularly homogeneous temperature profile. Each heating element can be independently actuated or adjusted.

A plurality of gas outlet apertures, which are preferably spread as uniformly as possible over the entire surface of the electrode, preferably pass through the electrode.

In a preferred configuration of the invention, a flow guide (which is preferably in the form of a frame) is disposed on the electrode, the flow guide extending in the direction of the substrate carrier.

Due to these structures, a uniform process gas flow in the direction of the substrate can be ensured, with the result that coating can be improved.

According to a further configuration of the invention, the distance between the electrode and the substrate carrier is changeable.

In view of the fact that the distance is fixedly defined in the conventional vacuum coating method, in the vacuum coating method according to the present invention, the substrate carrier (on which the substrate is held) and the electrode are The distance between them can be changed. By varying the distance between the substrate carrier (or opposite electrode) and the electrode, the coating process can be more uniformly constructed and the offset coating process can be It is stabilized by adjusting the distance between the electrode and the opposite electrode.

In this way, an improved implementation of the coating process (by automatically controlling the distance between the electrode and the opposite electrode) can be achieved.

The distance between the electrode and the substrate carrier can preferably be set such that a gap of about 2 to 20 mm, preferably about 2 to 5 mm, is retained in a flow guide and the substrate. Between.

The vacuum coating apparatus according to the present invention preferably operates in a batch mode.

For high throughput purposes, a vacuum coating installation can be coupled to a plurality of coating devices having a common loading unit, wherein at least one of the coating devices can be used for maintenance purposes The operation of the other coating apparatus is detached to become a maintenance unit, wherein the capacity of the remaining coating apparatus is designed such that the nominal capacity of the vacuum coating facility can be achieved without the maintenance unit.

In this way, maintenance work can be carried out in the service unit during a continuous coating process that does not need to be shut down. In this way, an average of about 97% of the uptime can be achieved.

It is possible to simultaneously operate all of the coating equipment belonging to the vacuum coating facility at a reduced capacity to achieve a nominal throughput capacity during normal operation.

Alternatively, a selected one of all of the coating equipment can be deliberately set to fail to shut down, while the remaining coating equipment is operated at a higher throughput capacity to maintain the total nominal production capacity. .

In this way, maintenance work can be performed during a continuous coating process. Implemented within the service unit, the coating facility need not be shut down. In this way, an average of about 97% of the uptime can be achieved.

The object of the present invention can also be achieved by a method for vacuum coating a substrate with a voltage applied between an electrode and an opposite electrode, wherein the substrate is disposed between On the substrate carrier between the electrode and a plate, the plate is preferably constructed of graphite and joined as the opposite electrode.

As already mentioned above, this method allows a more uniform implementation of the treatment 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 on the electrode and guided by the at least one flow guide in the direction of the substrate, suctioned The draw 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.

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 which is airtight The pattern is surrounded by a bottom 16, a wall 18 and a top 14. The coating chamber 12 has 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 disposed at a distance d 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, and is used for detecting A partial pressure sensor for a particular gas, and the like. It goes without saying that the sensor 28 is only indicated in a purely schematic manner and can be constructed to form any desired sensor, and several different sensors connected to the central controller 60 can be provided. . In any event, the distance d 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 With the help of 60, it is set according to one of the processing parameters to ensure 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. 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 loading 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 the same coating The units P1, P2, P3 have the same construction and thus serve as a reserve capacity. This means that the coating process is carried out at a nominal yield, while at the same time maintenance work (for example, cleaning work and the like) can be carried out in one unit (within the maintenance unit M) without derogation 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.

In a different configuration, all of the units P1 to P4 and M can be produced with reduced capacity to be used at the same time. For maintenance, one of the units M is disengaged from the remaining units P1 to P4, and the remaining units P1 to P4 of the units can be operated close to their maximum capacity, thereby being serviced in one unit M. At the same time, it can reach the nominal total Output capacity.

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 a vacuum coating apparatus in accordance with the present invention in a highly simplified and schematic illustration. A cross-sectional view; 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 arranged in a pentagonal manner in a central distribution unit Around, 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‧‧‧ arrow

60‧‧‧Central controller

62‧‧‧ sensor

64‧‧‧ Lifting drive

66‧‧‧Control line

68‧‧‧ lines

70‧‧‧Guide or frame

74‧‧‧ arrow

Claims (14)

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 further comprising An electrode (24) disposed above the substrate (30) to be coated, and an opposite electrode (32), wherein the substrate carrier (28) is held on a board (32), The board is connected as the opposite electrode. A vacuum coating apparatus according to claim 1, wherein the board (32) is made of graphite. A vacuum coating apparatus according to claim 1 or 2, wherein the board (32) is composed of a plurality of individual boards. A vacuum coating apparatus according to claim 1, wherein the board (32) is heated. A vacuum coating apparatus according to claim 4, wherein a plurality of heating elements (34) are disposed under the plate (32). A vacuum coating apparatus according to claim 5, wherein the heating elements (34) are dispersed as uniformly as possible under the surface of the board (32), wherein the heating elements (34) are preferably Can be adjusted independently. A vacuum coating apparatus according to claim 1, wherein a plurality of gas outlet openings (26) for feeding a processing gas pass through the electrode (24). A vacuum coating apparatus according to claim 1, wherein a flow guiding member (70), preferably in the form of a frame, is disposed at the electrode (24) The flow guide (70) extends in the direction of the substrate carrier (28). The vacuum coating apparatus of claim 1, wherein a distance (d) between the substrate carrier (28) and the electrode (24) is changeable during a coating process, such that an approx. A gap of 2 to 15 mm, preferably about 3 to 7 mm, particularly preferably about 4 to 5 mm, is held on the substrate carrier (28) and the flow guide (70) extending from the electrode (24) between. A vacuum coating facility having a plurality of coating apparatus (10) according to any of the preceding claims, coupled to a common loading unit (82), wherein the coating apparatus At least one of (10) may be detached from the operation of the remaining coating apparatus (10) for maintenance purposes to become a maintenance unit (M), wherein the capacity of the remaining coating equipment (10) is It is designed such that the nominal capacity of the vacuum coating facility can be achieved without the maintenance unit (M). A method of vacuum coating a substrate (30), comprising applying a voltage between an electrode (24) and an opposite electrode (32), further comprising feeding a processing gas, wherein the substrate (30) is disposed On a substrate carrier (28) interposed between the electrode (24) and a plate (32), the plate (32) is preferably constructed of graphite and joined as the opposite electrode. The method of claim 11, wherein the process gas system is fed through a plurality of gas outlet openings (26) on 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 portion of the coating chamber (12) area. A method of vacuum coating a substrate (30), comprising providing a vacuum coating facility having a plurality of coating apparatus (10) according to any of the preceding claims, wherein each coating apparatus ( The configuration of 10) is the same and is coupled to a common loading unit (82), wherein one of the coating devices (10) is from the remaining coating device (10) for maintenance purposes. Disengaged to become a maintenance unit (M), wherein the vacuum coating facility has a nominal throughput capacity, and wherein the coating facility is missing one of the coating devices (10) The selected coating apparatus is operated at the nominal throughput rate, and the selected coating equipment in the remaining coating equipment (10) is from the remaining coating equipment for maintenance purposes (10) Disengaged from the operation. The method of claim 13, wherein each of the plurality of coating apparatuses (10) simultaneously has a capacity lower than its nominal production rate during normal operation. Being operated, and for maintenance purposes, a selected coating device of the coating apparatus (10) is detached from the remaining equipment (10), while the remaining coating equipment (10) is normal The capacity during operation is also high enough to operate at a capacity close to its maximum yield capacity.