KR20130103737A - Gas distribution device for vacuum processing equipment - Google Patents

Abstract

The present invention provides a plurality of positions in which gas (A, B) is directed toward a substrate from a gas inlet (7) connected to a gas source and a plurality of outlet openings (8) to receive a gas (A, B). In a vacuum chamber containing a substrate to be processed in a vacuum treatment comprising a gas distribution system 9 for dispensing into a vacuum chamber, the gas distribution system 9 comprises a first plate 10 and a first plate each having a flat side. 2 plates 5; The first plate 10 represents a plurality of holes 4 forming the outlet opening 8; The second plate 5 represents a plurality of channels 6a, 6b arranged on the flat side, with each hole 4 of the first plate 10 being a channel 6a, 6b of the second plate 5. Arranged at the end, so that the gas A, B can be dispensed into the holes 4 through the respective channels 6a, 6b, the first plate 10 and the second plate 5 have their own flat surfaces. The side chambers are mounted together in direct contact with each other, and each channel 6a, 6b is integrated into at least one common channel 6a, 6b connected to the gas inlet 7, forming a branching arrangement. It is about. The vacuum chamber includes a gas distribution system 9 for improving the quality of the substrates produced, as well as for significantly improving substrate coating homogeneity and reducing manufacturing costs.

Description

GAS DISTRIBUTION DEVICE FOR VACUUM PROCESSING EQUIPMENT}

The invention relates to a vacuum chamber for receiving a substrate to be processed in a vacuum process comprising a gas inlet connected to a gas source for receiving gas and a plurality of gas inlets from the gas inlet toward the vacuum chamber at a plurality of locations facing the substrate. To a gas distribution system for distributing gas to an outlet opening. In particular, the present invention relates to a system for uniformly distributing precursor gas (s) in a low pressure CVD reactor. This gas distribution system can be applied to all chemical vapor deposition reactors to improve local gas flow uniformity and coating homogeneity. The system makes it possible to deliver the reaction precursors independently, for example, without premixing near the substrate surface to reduce parasitic adhesion on the reactor.

Thin film deposition or coating processes are well known in the art. Since then, adhesion uniformity is an important criterion, especially in the manufacture of large area coatings. The layer properties that are realized on a small scale in today's thin film technology need to be extended to large area substrates of such thin film technology. In general, the tighter the specification for integration at small areas, the better the uniformity at large areas needs to be. A typical example is the IC industry, where several thin film layers are coordinated with each other. This adjustment needs to be maintained for the entire wafer, which requires good uniformity of all layers involved in all critical features for the entire substrate.

A similar example is thin film solar cell applications. Battery features that enable high efficiency need to be applied to the entire integrated module. An area with "out of specification" characteristics that will exhibit low efficiency resulting in high resistance in series connections will deteriorate each cell. As a result, areas of poor cell characteristics degrade the overall performance of a complete solar cell module.

In chemical vapor deposition (CVD) processes, temperature uniformity and gas distribution homogeneity are the most important factors. Thus, the most relevant component of a low pressure CVD (LPCVD) reactor is also a 'hot plate', which activates the chemical reaction of precursors on a substrate in a vacuum enclosure that can be pumped to a pressure below atmospheric pressure. Called, the heated substrate carrier and (ii) a gas plenum for distributing the precursor within the reaction chamber. The gas plenum may have a different design, but as shown in FIG. 1, generally a cooling unit 1, a gas shower unit 2, and a piping net for distributing the gas to reduce the parasitic coating on the gas plenum. (piping net) (3)

The tubing 3 usually represents a hole 4 which is easily distributed over its entire length to allow for the injection of gas and / or precursors. The hole 4 can be included in the chamber separately from the actual process space to allow the incoming gas to be easily dispensed even at the location of the hole 4 where the local pressure peak can rise. The shower plate or shower head is a gas shower unit 2 which allows gas to be transferred from the injection chamber to the process space using a distribution through the perforated plate, ie the hole 4.

This distribution of gas or precursor in the plenum using the plumbing net 3 is known in the art but includes the disassembly of all pipes, the check of the overall direction of the pipe at the installation stage, a large number of seal checks between the frame and the pipe, and the like. Requires complex management.

In addition, the flow uniformity obtained in the piping net 3 is significantly limited in the possibility of improving it without poor and very complicated design. In this configuration, the distribution pipe of the tubing net 3 is located behind the cooling / shower plate, the gas shower unit 2, in a separate volume as described above. The precursors may mix within this volume and even partially react. Such parasitic attachment can occur within the gas plenum and can degrade some gas distributor functions as a function of service time. In order to avoid only chemical reaction of the precursor in the gas plenum, two or more independent piping lines must be used that further increase the complexity of the overall distribution system and reduce design freedom.

Accordingly, it is an object of the present invention to overcome the aforementioned difficulties of the prior art, ie to provide an improved uniformity of gas distribution onto a substrate to be processed in a vacuum chamber and thus to improve the coating homogeneity of the substrate. It is to provide a vacuum chamber having a system.

This object is achieved by the independent claim. Advantageous embodiments are described in detail in the dependent claims.

In particular, the object is a vacuum chamber for containing a substrate to be processed in a vacuum process comprising a gas inlet connected to a gas source for receiving gas and a plurality of outlets from the gas inlet toward the vacuum chamber at a plurality of locations facing the substrate. Achieved by a gas distribution system for distributing gas into the opening, the gas distribution system comprising a first plate and a second plate, each plate having a flat side, the first plate having a plurality of holes defining an outlet opening The second plate represents a plurality of channels arranged on the flat side, and the first plate is arranged such that each hole of the first plate is arranged at the end of the channel of the second plate so that gas can be dispensed through the respective channel into the hole. The plate and the second plate are fixed so that the flat sides are in contact with each other, and each channel is merged into at least one common channel connected to the gas inlet, Form an array.

Accordingly, the present invention provides a binary tree represented by a uniform flow distribution of gas, with channels for the delivery, separation and / or distribution of a gas, for example a "low reactive" gas or gas mixture, from the gas inlet to the plurality of outlet openings. It is based on the central idea for providing a second plate, namely a gas distribution plate. As a result, a uniform gas flow is achieved in which a uniform coating of the substrate is achieved. In summary, the vacuum chamber containing the gas distribution system provides a significant improvement in substrate coating homogeneity, thus reducing the manufacturing cost and at the same time improving the quality of the manufactured substrate.

The term "processing" in the sense of the present invention includes any chemical, physical and / or mechanical effect acting on the substrate.

The term "substrate" in the sense of the present invention includes the part, part or workpiece to be treated with the vacuum processing system according to the invention. The substrate is not limited to flat, plate-shaped portions having a rectangular, square or circular shape. Preferably, the substrate is suitable for making thin film solar cells and includes float glass, security glass and / or quartz glass. More preferably, the substrate is provided in essence, most preferably a fully planar substrate having a plane of at least 1 m ² , such as a thin glass plate.

The term "vacuum processing" or "vacuum treatment system" in the sense of the present invention includes at least one enclosure for a substrate to be treated at a pressure below ambient atmospheric pressure.

In the sense of the present invention "CVD", chemical vapor deposition, and the term of that kind encompass well known techniques that allow the deposition of layers on heated substrates. Usually a liquid or gaseous precursor material is supplied to the treatment system, and thermal reaction of the precursor provides adhesion of the layer. Often, DEZ (diethyl zinc) is used as precursor material for the production of TCO layers in vacuum processing systems using low pressure CVD (LPCVD). The term "TCO", which stands for transparent conductive oxide, or TCO layer, is a transparent conductive layer and the terms layer, coating, adhesion and film are CVD, LPCVD, Plasma Enhanced CVD (PECVD) or Physical Vapor Deposition (PVD). It is used interchangeably in the present invention for the film attached in the vacuum treatment.

The term "solar cell" or "photovoltaic cell (PV cell)" in the sense of the present invention refers to an electrical component that can convert light, essentially sunlight, into electrical energy directly by the photovoltaic effect. Include. A first or front electrode, one or more semiconductor thin film PIN junctions, and a second or back electrode, which are generally successively attached to a substrate by a thin film solar cell. Each PIN junction or thin film photoelectric conversion unit includes an i-type layer formed sandwiched between a p-type layer and an n-type layer, where "p" indicates positively doped and "n" indicates negatively doped. The i-type layer, which is a substantially intrinsic semiconductor layer, accounts for most of the thin film PIN junction thickness and photoelectric conversion mainly occurs in this i-type layer. Therefore, it is preferable that a board | substrate is a board | substrate used for thin film photovoltaic cell manufacture.

The term "flat" in the sense of the present invention includes means having a surface that is not rough, that is, does not include grooves or the like. Preferably the term "flat" means that the surface roughness grade of each surface is less than or equal to N9.

The term "gas" in the sense of the present invention means any gas suitable for the provision of a coating in a CVD process, in particular for the formation of a coating necessary for the manufacture of solar cells. Preferably, the first plate is provided with a gas shower plate arranged in a vacuum chamber adjacent the substrate. The second plate is preferably provided as a distribution plate for gas distribution across the surface of the substrate. More preferably, each channel comprises two stages and is provided in a pipe-like or tubular manner for delivering gas from the first stage to the second stage. When the channel is connected to the hole, the gas delivered to the channel is preferably completely dispensed into the hole for supply onto the substrate.

In a further preferred embodiment, the gas distribution system comprises a back plate having a flat side, a second plate representing two opposing flat sides and a channel on two sides, the back plate and the second plate being two of the second plate. The flat sides are fixed to each other so that the flat sides are in direct contact with each other so that gas can be distributed through the channels on the two sides. This means that each side of the second plate is designed to deliver, separate and / or distribute, for example, two different, independent gases that can be mixed in a vacuum chamber for reaction onto the substrate. In this way, it is more preferable that each channel of the two sides of the second plate is integrated side by side into at least one common channel so that gas can be distributed to each channel of each side of the second plate. In other words, the gas distribution system preferably includes two different common channels, each provided on one side of the second plate for supplying gas to the plurality of channels. Preferably the first plate, second plate and / or back plate are arranged parallel to each other.

In another preferred embodiment, the second plate comprises a plurality of second holes such that gas from two channels on two sides of the second plate can be dispensed into the same hole forming a common outlet opening for the gas. This means, for example, that two different gases are mixed in the second plate, for example to be highly reactive, and then directly injected into a vacuum chamber, ie the reaction chamber. For this configuration, no premixing of the gas occurs in the gas plenum provided in the vacuum chamber, which minimizes parasitic adhesion in the gas plenum. As a result, the amount of injected gas used to coat the substrate is thus increased.

In an alternative embodiment, the second plate comprises a plurality of agents each associated with the holes such that gas from the channels on two sides of the second plate can be dispensed into respective holes respectively forming separate outlet openings for each gas. Contains 2 holes. This means that gas mixing according to this embodiment takes place in the gas plenum, which advantageously reduces parasitic adhesion in the channel.

In a particularly preferred embodiment, the end of the at least one channel is positioned adjacent to the other channel such that the gas dispensed from one channel to the other channel is evenly divided between the two ends of the other channel. More preferably, the channels are separated by a binary tree method which forms a branching arrangement between the gas inlet and the gas outlet openings so that the gas dispensed in the branching arrangement is divided evenly across all the outlet openings. In another preferred embodiment, the channel is provided such that the gas path length between the gas inlet and each outlet opening is the same. According to this embodiment, the gas entering the common channel is divided again by a plurality of channels towards a plurality of outlet openings, each having the same gas path length, and at least so as to be preferably uniformly distributed along the substrate surface in the vacuum chamber. One channel is preferably divided into other channels to form a more dendritic gas distribution system. Thus, each embodiment further increases the flow uniformity to improve the coating quality of the substrate.

In another preferred embodiment, the channel is provided in a way that narrows between the common channel and the end of each channel located in the hole and the common channel has a depth of 3 mm or less and a width of 16 mm or less, and the end of the channel arranged in the hole is Each has a depth of 1.5 mm or less and a width of 3 mm or less, and the holes each have a diameter of 2.2 mm or less. Designing a channel having the size described above is a complete substrate to which the channel is to be treated, compared to prior art systems, for example, in a narrowing fashion with a uniform gas path length for thin film solar cells, especially for all outlet openings. When appearing with a very uniform gas distribution on the surface, it is possible to significantly improve the coating quality of the substrate. More preferably, the thickness of the second plate is 15 mm or less, thus reducing manufacturing costs as compared to prior art systems.

In general, the gas flow rate into the channel can have any flow rate. However, it has been found to be particularly advantageous when channels and holes are provided such that the gas flow from the gas inlet to the outlet opening is less than 1 standard liter per minute (slm) per side of the second plate. Designing channels and holes in this way further optimizes coating quality due to improved uniform distribution of precursors, ie gases. Variable of 1% of DEZ flow as gas and 1 ° C. of substrate temperature can result in variations of thickness, 6 nm and 25 nm of coating, respectively.

In another preferred embodiment, the gas distribution system comprises means for cooling the second plate, which means preferably comprises 13 l / min of coolant at 24 ° C. The cooling means not only prevent adhesion on the surface of the second plate that is exposed to the thermal reactor components of the vacuum chamber, but also reduce parasitic adhesion in the gas distribution system, especially when the gases are premixed according to the embodiments described above. .

In general, the channel can be provided by any method known in the art for distributing gas from the gas inlet to the outlet opening, and it is therefore particularly preferred that the channel is provided in the groove. In a similar way, the holes are preferably provided as holes through the first plate, thus allowing for easy manufacture.

These and other aspects of the invention will be apparent from and elucidated with reference to the examples described below.
1 shows a gas distribution system according to the prior art.
2 shows a top view of a binary tree gas distribution system in accordance with a preferred embodiment of the present invention.
3 shows a side view of a binary tree gas distribution system in accordance with a preferred embodiment of the present invention.
4A illustrates gas mixing in a binary tree gas distribution system in accordance with another preferred embodiment of the present invention.
4B illustrates gas mixing in a binary tree gas distribution system in accordance with another embodiment of the present invention.
5A illustrates a side view of a binary tree gas distribution system in accordance with another embodiment of the present invention.
5B illustrates a top view of a binary tree gas distribution system in accordance with another embodiment of the present invention.

In order to uniformly and independently distribute the other precursors to the reaction chamber, ie the vacuum reaction chamber for the treatment of the substrate in a vacuum process, the present invention does not utilize a piping distribution net 3 as shown in FIG. 1 of the prior art. Construct a new design.

In this new design, the gas distribution is controlled using a so-called binary tree gas distribution plate, ie a second plate 5 as shown in the top view of FIG. 2. As shown in FIG. 3, the second plate 5 comprises groove channels 6a, 6b on both sides. Each side is designed for transferring, separating and dispensing one "low reactive" gas A, B or gas mixture from the gas inlet 7 to all outlet openings 8. The groove size of the channels 6a, 6b is such that a smooth pressure change in the binary tree gas distribution system 9 is a separate gas for the other gas at each side of the gas inlet 7, for example the second plate 5. It is selected to be obtained with 1024 outlet openings 8 from the inlet 7.

To reduce manufacturing costs using faster drilling, larger but coarse grooves can be made. As a result, a second plate 5 of 15 mm can be used as the gas distribution plate. In one embodiment, the depth of the groove is between 3 mm at the inlet close to the gas inlet 7 and 1.5 mm at the end of the channels 6a, 6b at the outlet opening 8. At the same time, the width of the channels 6a, 6b is reduced from 16mm to 3mm, so that the diameter of the outlet opening 8 is 2.2mm. The flow of gases A, B used with this configuration of the second plate 5 is about 1 slm per distribution side, ie per side of the second plate 5.

As shown in FIG. 2, at least one gas A, B, which is distributed from one channel 6a, 6b to another channel 6a, 6b, is evenly separated between both ends of the other channel 6a, 6b. Channels 6a and 6b are located adjacent to other channels 6a and 6b. In this way, the gas distribution system 9 forms a binary tree branch arrangement between the gas inlet 7 and all outlet openings 8.

In order to mix two different gases A and B, two different configurations are possible, as shown in FIGS. 4A and 4B. In the first configuration, as shown in FIG. 4A, at the outlet opening 8 in which the gases A, B are provided as holes 4, the first plate 5 is mixed in, and then the reaction chamber ( 11) is injected. In this configuration, no premixing of gases A, B occurs in the reaction chamber 11 which minimizes parasitic adhesion in the gas line or gas plenum, for example plenum. Thus, the actual amounts of the injected gases A and B used for the substrate coating, which is gas utilization, increase. In addition, the gas shower plate, that is, the first plate 10, is water cooled by the cooling means 12. At a cooling rate of 13 l / min at 24 ° C., it not only prevents adhesion on the surface exposed to the thermal reactor components, but also within the gas shower piping 5 in which gases A and B are premixed, ie outlet opening 8. Reduces parasitic adhesions within.

As shown in FIGS. 4A and 4B, each hole, which is the outlet opening 8 of the first plate 10, is arranged at the end of the channels 6a, 6b of the second plate 5, so that gas A The first plate 10 and the second plate 5 are mounted together with the flat sides in direct contact with each other so that B can be dispensed through the respective channels 6a and 6b to the outlet opening 8.

In the second configuration shown in FIG. 4B, the premixing of gases A and B in the gas shower plate, which is the first plate 10, does not occur, but occurs directly in the reaction chamber 11. This configuration minimizes parasitic deposition in the grooves of the channels 6a and 6b.

According to the design of the gas distribution system 9 of the present invention, the gas path length between the gas inlet 7 and each outlet opening 8 is uniform with all other gas paths in the second plate 5 and is thus uniform. As a result of one gas A, B flow distribution. With this uniform gas A, B flow, and also at a uniform substrate temperature, a uniform coating of the substrate can be obtained. For this process, a 1% variation in the DEZ (Diethyl Zinc) flow, a 1 ° C variation in the flow and substrate temperature can result in a variation of about 6 nm and 25 nm of the thickness coating, respectively.

4a and 4b show that channels 6a and 6b on both sides of the second plate 5 are between the second plate 5 and the back plate 14 and between the second plate 5 and the separating plate ( The back plate 14 is shown as well as the separating plate 13 provided between the first plate 10 and the second plate 5 so as to be provided between the 13 plates. The second plate 5 is such that gas A, B from the two channels 6a, 6b on both sides of the second plate 5 can be introduced into the same hole 4 as in FIG. 4a or in FIG. 4b. As described above, a plurality of second holes 15 are included so that gases A and B can be introduced into the respective holes 4 on each side.

In the above-described binary tree gas distribution system 9 according to the invention, it is possible to integrate gases A, B directly from the reactor side, no longer from the top, as indicated by the prior art and by reference numeral 16 in FIG. 5A. . Thus, referring also to FIG. 5B, only one additional groove 17 is required which forms the common channels 6a, 6b. This variant makes it possible to significantly reduce the overall plenum thickness suitable for integration in the stacked arrangement of the reactor, compared to the prior art. Replacing conventional piping with additional grooves 16 for delivering gas A, B to the center of the plate 5 also reduces manufacturing costs.

While the invention has been shown and described in detail in the drawings and foregoing description, these drawings and description are to be considered illustrative and exemplary and not restrictive; The invention is not limited to the described embodiments. Other variations of the embodiments to be disclosed can be understood and influenced by those skilled in the art in practicing the claimed invention from the study of the drawings, the specification and the appended claims. In the claims, the term comprising does not exclude other elements or steps, and the term "one" does not exclude a plurality. Only the fact that certain methods may be cited in different dependent claims does not indicate that a combination of these methods may not be usefully used. All reference signs in the claims should not be construed as limiting the scope.

1 cooling unit
2 gas shower units
3 piping net
4 holes
5 second edition
6a, 6b channel
7 gas inlet
8 Outlet opening
9 gas distribution system
10 first edition
11 reaction chamber
12 Cooling means
13 separator plate
14 backplane
15 second hole
16 reference signal
17 additional grooves

Claims (14)

The gas (A, B) at a plurality of locations toward the substrate from a gas inlet (7) connected to a gas source and a plurality of outlet openings (8) from the gas inlet (7) to receive gas (A, B); A vacuum chamber containing a substrate to be processed in a vacuum treatment comprising a gas distribution system 9 for dispensing into a vacuum chamber,
The gas distribution system 9 comprises a first plate 10 and a second plate 5 each having a flat side;
The first plate (10) represents a plurality of holes (4) forming the outlet opening (8);
The second plate 5 represents a plurality of channels 6a, 6b arranged on the flat side,
Each hole 4 of the first plate 10 is arranged at the end of the channels 6a, 6b of the second plate 5 so that the gas A, B is separated from the respective channels 6a, 6b. The first plate 10 and the second plate 5 are mounted together with their flat sides in direct contact with each other so that they can be dispensed into the holes 4 through
Each of the channels 6a, 6b is integrated into at least one common channel 6a, 6b connected to the gas inlet 7, forming a branching arrangement,
Vacuum chamber.
The method of claim 1,
The gas distribution system 9 comprises a back plate 14 having a flat side, the second plate 5 comprises two opposing flat sides and channels 6a and 6b on the two sides, The back plate 14 and the second plate 5 have a flat side so that the gas A, B can be distributed through the channels 6a, 6b on the two sides of the second plate 5. Mounted together in direct contact with each other,
Vacuum chamber.
The method according to claim 1 or 2,
Each channel 6a of the two sides of the second plate 5 such that the gas A, B can be distributed to respective channels 6a, 6b of each side of the second plate 5. 6b) is integrated into at least one common channel 6a, 6b,
Vacuum chamber.
The method according to claim 2 or 3,
Gases A, B from two channels 6a, 6b on both sides of the second plate 5 form the same holes 4 forming a common outlet opening 8 for the gases A, B. The second plate 5 comprises a plurality of second holes 15 so as to be dispensed with
Vacuum chamber.
The method according to claim 2 or 3,
From the channels 6a, 6b on the two sides of the second plate 5, each of the gases A, B forms an outlet opening 8 separated for each gas A, B for each side. The second plate 5 comprises a plurality of second holes 15 each associated with the hole 4 so that it can be dispensed into the holes 4.
Vacuum chamber.
The method according to any one of claims 1 to 5,
At least one channel (A, B) so that the gas (A, B) distributed from one channel (6a, 6b) to the other (6a, 6b) is evenly distributed between the two ends of the other channel (6a, 6b) The ends of 6a, 6b are located in contact with the other channels 6a, 6b,
Vacuum chamber.
7. The method according to any one of claims 1 to 6,
The channels 6a, 6b are diverged between the gas inlet 7 and the outlet opening 8 so that the gases A, B distributed in the branching arrangement are uniformly distributed over all outlet openings 8. Arranged in a binary tree way to form an array,
Vacuum chamber.
8. The method according to any one of claims 1 to 7,
The channels 6a, 6b are provided such that a gas path length is the same between the gas inlet 7 and each outlet opening 8,
Vacuum chamber.
The method according to any one of claims 1 to 8,
The channels 6a and 6b are provided in a manner narrowed between the common channels 6a and 6b and the ends of respective channels 6a and 6b located in the apertures 4 and the common channels 6a and 6b. 6b) has a depth of 3 mm or less and a width of 16 mm or less, and the ends of the channels 6a, 6b located in the hole 4 have a depth of 1.5 mm or less and a width of 3 mm or less, respectively, 4) each have a diameter of 2.2 mm or less,
Vacuum chamber.
10. The method according to any one of claims 1 to 9,
The thickness of the second plate 5 is 15 mm or less,
Vacuum chamber.
11. The method according to any one of claims 1 to 10,
The channels 6a, 6b and the holes 4 are provided such that the gas flow from the gas inlet 7 to the outlet opening 8 is 1 slm or less per side of the second plate 5. ,
Vacuum chamber.
12. The method according to any one of claims 1 to 11,
The gas distribution system 9 comprises means 12 for cooling the second plate 5,
Vacuum chamber.
13. The method according to any one of claims 1 to 12,
The channels 6a, 6b are provided as grooves,
Vacuum chamber.
The method according to any one of claims 1 to 13,
The hole 4 is provided as a hole passing through the first plate 10,
Vacuum chamber.

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