KR20140037198A - Method and system for inline chemical vapor deposition - Google Patents

Abstract

An inline chemical vapor deposition method and system for manufacturing a device is disclosed. The method includes transporting a web or individual substrate through a deposition chamber having a plurality of deposition modules. A buffer layer, a window layer, and a transparent conductive layer are deposited on the substrate while passing through the first deposition module, the second deposition module, and the third deposition module, respectively. Advantageously, the steps of creating the buffer layer, the window layer, and the transparent conductive layer are performed sequentially in a common vacuum environment of a single deposition chamber, eliminating the use of conventional chemical solution deposition processes to deposit the buffer layer. The method is suitable for the production of different types of devices including various types of solar cells, such as copper indium gallium diselenide solar cells.

Description

METHOD AND SYSTEM FOR INLINE CHEMICAL VAPOR DEPOSITION}

This application is entitled “Inline Chemical Vapor Deposition System” and is a continuation-in-part of US patent application Ser. No. 12 / 767,112, filed April 26, 2010, entitled “Method and System for Inline Chemical Vapor Deposition ”and claims priority to US patent application Ser. No. 13 / 156,465, filed June 9, 2011, which is incorporated herein by reference.

The present invention generally relates to chemical vapor deposition systems and methods. More specifically, the present invention relates to a chemical vapor deposition system for inline processing of web substrates and discrete element substrates.

Chemical vapor deposition (CVD) is a process used to deposit thin films of semiconductors, dielectrics, metals, and the like on the surface of a substrate. In normal CVD techniques, one or more precursor molecules, each in gas phase, are introduced into a process chamber containing a substrate. The reaction of these precursor gases at the surface of the substrate is initiated or enhanced by adding energy. For example, energy can be added by increasing the surface temperature or by exposing the surface to a plasma discharge or ultraviolet (UV) radiation source.

The quality of the film deposited by the CVD reaction taking place in the gaseous state depends heavily on the uniformity of precursor gas flows. Non-uniform gas flow near the substrate surface can yield unsatisfactory film uniformity, and can result in shadowing artifacts due to surface features such as steps and vias. High-volume processing of wafers and other individual substrates and high speed processing of web substrates of a roll-to-roll deposition system are not limited to known systems and methods for CVD processing, and include material utilization. ) And other factors can be expensive to operate.

Atomic layer deposition (ALD) is another technique in which films are deposited on the surface of a substrate. According to the ALD process, a first precursor gas flow is used to react with the surface to create a monolayer. The first precursor gas flow is stopped and then the second precursor gas flow is used to create another monolayer. These two-stage "pulsing" precursor gases are repeated several times until a thin film of a single material of the desired thickness is formed. In other versions of the ALD process, more than two precursor gas flows are used sequentially to produce thin films. The introduction of each precursor gas into the reaction chamber may occur after the introduction of purge gas to ensure that the previous precursor gas is removed, thereby reducing or preventing unwanted deposition byproducts. Despite providing good thickness control, the ALD process of creating alternating monolayers on the surface of the substrate is time intensive and significantly limits throughput.

In one aspect, the invention features an inline chemical vapor deposition method for manufacturing a device. The method includes transporting the substrate through a deposition chamber having a vacuum environment and a first deposition module, a second deposition module, and a third deposition module. During transport of the substrate through the first deposition module a buffer layer is deposited over the substrate. During transportation of the substrate through the second deposition module a window layer is deposited over the buffer layer. A transparent conductive layer is deposited over the window layer during transportation of the substrate through the third deposition module.

In another aspect, the invention features an inline chemical vapor deposition method for manufacturing a device. The method includes transporting a substrate having a metal layer and an absorber layer at a fixed rate through a deposition chamber having a vacuum environment and a first deposition module, a second deposition module, and a third deposition module. Each deposition module includes at least one deposition station having a manifold comprising a first precursor port, a pair of second precursor ports, and a pair of pumping ports. Include. The first precursor port is disposed between the second precursor ports, and the pair of second precursor ports are disposed between the pumping ports. The first precursor port and the pair of second precursor ports are configured to be coupled to the first precursor gas source and the second precursor gas source, respectively. The pumping ports are coupled to the discharge system and configured to discharge the first precursor gas and the second precursor gas. The method includes depositing a buffer layer on the substrate during transport of the substrate through the first deposition module; Depositing a window layer on the buffer layer during transport of the substrate through the second deposition module; And depositing a transparent conductive layer in the window layer during the passive of the substrate through the third deposition module.

In another aspect, the invention features an inline chemical vapor deposition system that includes a deposition chamber, a continuous transport system, and first, second, and third deposition modules. Continuous delivery systems transport the substrate along a path through the deposition chamber. The first, second, and third deposition modules are disposed in the path within the deposition chamber. The first deposition module has at least one deposition station for depositing a buffer layer on the substrate, the second deposition module has at least one deposition station for depositing a window layer on the buffer layer, and the third deposition module is transparent to the window layer. It has at least one deposition station for depositing a transparent conductive layer. Each deposition module includes at least one deposition station having a manifold. Each manifold includes a first precursor port, a pair of second precursor ports, and a pair of pumping ports. The first precursor port is disposed between the second precursor ports, and the pair of second precursor ports are disposed between the pumping ports. The first precursor port and the pair of second precursor ports are configured to be coupled to the first precursor gas source and the second precursor gas source, respectively. The pumping ports are coupled to the discharge system and configured to discharge the first precursor gas and the second precursor gas.

The above and further advantages of the present invention can be better understood by referring to the following description in conjunction with the accompanying drawings, in which like reference characters designate the same structural elements and features in the various drawings. For clarity, all components in all drawings may not be given reference numerals. The drawings are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the invention.
1 illustrates an inline CVD system according to one embodiment of the invention.
2A illustrates a web substrate being transported past a manifold of a deposition station in accordance with one embodiment of the present invention.
2B illustrates a web substrate being transported past a manifold of a deposition station in accordance with another embodiment of the present invention.
2C illustrates a web substrate being transported past a manifold of a deposition station in accordance with another embodiment of the present invention.
3A is a block diagram of the manifolds of the deposition stations of FIG. 1 integrated as a single structure in accordance with an embodiment of the present invention.
FIG. 3B is a top view of the web substrate for the precursor ports and pump ports shown in FIG. 3A.
4A is a front perspective view of an integrated deposition station module in accordance with an embodiment of the present invention.
4B is a rear perspective view of the integrated deposition station module shown in FIG. 4A.
4C is a cross-sectional view of the integrated deposition station module shown in FIG. 4A.
5 illustrates an inline CVD system according to another embodiment of the present invention.
6 illustrates an example of a device structure that may be achieved using an inline CVD method in accordance with embodiments of the present invention.
7 illustrates an inline CVD system according to another embodiment of the present invention.
8 illustrates an inline CVD system according to another embodiment of the present invention.
9 is a flow diagram illustrating an inline CVD method for fabricating a device in accordance with one embodiment of the present invention.

The steps of the methods of the present invention may be performed in any order using the operable results, and two or more steps may be performed simultaneously unless otherwise described. Further, the systems and methods of the present invention may include any one or combination of the described embodiments in an operable manner.

The teachings of the present invention relate to systems and methods for reactive gas state processing, such as CVD, MOCVD, and halide vapor phase epitaxy (HVPE) processes. In conventional semiconductor material reactive gas state processing, semiconductor wafers are mounted to a carrier in a reaction chamber. A gas distribution injector is configured to face the carrier. Typically, the injector includes a gas inlet containing a plurality of gases or a combination thereof. The injector directs the gas or combination of gases to the reaction chamber. Commonly, injectors are showerhead devices arranged in a pattern that allows precursor gases to react as close to each wafer surface as possible to maximize the efficiency of reaction processes and epitaxial growth at the surface. devices).

Some gas distribution injectors include shrouds to help provide laminar gas flow during the CVD process. One or more carrier gases may be used to help generate and maintain the lamina gas flow. Carrier gases do not react with precursor gases or otherwise affect the CVD process. A typical gas distribution injector directs precursor gases from the gas inlet to target regions of the reaction chamber where wafers are processed. For example, in some MOCVD processes, a gas distribution injector introduces a combination of precursor gases, including metal organics and hydrides, into the reaction chamber. A carrier gas such as hydrogen or nitrogen or an inert gas such as argon or helium is introduced through the injector into the chamber to help maintain the lamina flow on the wafer. The precursor gases mix and react in the chamber to form a film on the wafer.

In MOCVD and HVPE processes, wafers are typically kept at a high temperature and precursor gases are typically kept at a low temperature when introduced into the reaction chamber. As the gases flow through the hotter wafer, the temperature of the precursor gases and the available energy for the reaction increase.

One common type of CVD reaction chamber includes a disk shaped wafer carrier. The carrier has pocket or structural features arranged to hold one or more wafers on the top surface of the carrier. During CVD processing, the carrier is rotated about a vertical axis extending perpendicular to the wafer-bearing surface. Rotation of the carrier improves the uniformity of the deposition material. During rotation, precursor gases are introduced into the reaction chamber from the flow suction element above the carrier. The flow gases are preferably passed down through the wafer in a lamina plug flow. As the gases approach the rotating carrier, viscous drag causes the gases to rotate about their axis. As a result, gases at the carrier surface and in the boundary region near the wafer flow outwards along the axis periphery towards the edge of the carrier. The gases flow past the carrier edge and flow down toward one or more outlet ports. Typically, the MOCVD process is performed using a series of different precursor gases and, in some embodiments, different wafer temperatures to deposit a plurality of different layers, each having a different composition, to form a device.

CVD processes such as MOCVD and HVPE are typically limited in processing capacity. Conventional systems and methods for CVD processing are not suitable for supporting high-speed processing of web substrates and high volume processing of wafers and other individual substrates in a roll-to-roll deposition system without useless equipment.

The systems and methods of the present invention are suitable for in-line CVD processing of web substrates and individual substrates. The systems and methods are particularly suitable for high throughput processing in which a single layer is deposited on a substrate, such as in the manufacture of solar cells and flat panel displays. In this exemplary application, zinc oxide is deposited on the substrate to produce solar cells. In another exemplary application, indium tin oxide is deposited on a substrate as part of a manufacturing process for a flat panel display. As used herein, the substrate is a superstrate, i.e. a supporting layer, which is the first layer of the device for receiving incident light. This system offers several advantages over conventional deposition systems. The quality of the deposited film is improved and the cost of the process equipment is reduced. Moreover, operating costs are lower, in part due to more efficient material utilization. For example, the material utilization is significantly greater than the target material utilization in conventional sputtering systems.

1 illustrates an inline CVD system 10 in accordance with an embodiment of the present invention. In-line CVD system 10 includes a web transport system for transporting web substrate 14 through deposition chamber 18 in a continuous manner. The web transport system includes a feed roller 22A and a receiving roller 22B. Feed roller 22A is the source of web substrate 14 to be processed. The receiving roller 22B receives the web substrate 14 after the deposition is completed, and holds the web substrate 14 in the form of a roll. Additional rollers 22C are disposed in the deposition chamber 18 between the feed roller 22A and the receiving roller 22B to accurately control the path of the web substrate 14. The web transport system transports the web substrate 14 at a substantially fixed rate along the path. Optionally, purge gases can be introduced into various chamber locations, or payout chamber 20A and takeup chamber 20B, to keep chamber walls clean from parasitic deposition. have.

Deposition chamber 18 is maintained at low pressure (eg, 1 torr LPCVD process) or atmospheric pressure (eg, APCVD process), as is known. The deposition chamber 18 includes a plurality of deposition stations 26 disposed adjacent to the path of the web substrate 14. Only three deposition stations 26 are shown for clarity in the illustrated embodiment, and it will be appreciated by those skilled in the art that the number of deposition stations 26 may be different. Each deposition station 26 includes a manifold coupled to the precursor gas source 28. Each deposition station 26 provides precursor gases of lamina flow between the manifold and the proximal surface of the web substrate 14 for the precursor gases to react near the web substrate to deposit the film. In some embodiments, one or more of the precursor gases of the lamina flow are operated using RF power or microwave power according to Plasma Enhanced CVD (PECVD) as is known.

Unlike conventional MOCVD reaction chambers, precursor gases are introduced below the substrate 14 in the opposite vertical direction of the flow, ie the gases flow upwards towards the surface to be coated. As a result, unwanted by-products of the reaction of precursor gases do not contaminate or interfere with the deposition process that may occur in the downstream precursor gas flow configuration.

The deposition chamber 18 includes a heater for heating the web substrate 14 during the CVD process. In the illustrated embodiment, a heating module 24, such as a radiant heater, is located proximate the web substrate 14 opposite each of the deposition stations 26 to heat the web substrate 14 to a desired process temperature. In alternative embodiments, one or more heaters are in thermal contact with web substrate 14. Those skilled in the art will appreciate that several different types of heaters may be used to heat the web substrate 14.

The path of the web substrate 14 is configured to pass through the manifold of the deposition station 26 in a series of ways so that a single layer of material of the desired thickness is deposited before the web substrate 14 arrives at the receiving roller 22B. More specifically, a material film is deposited on the web substrate 14 while passing through the first deposition station 26A. The web substrate 14 then passes through a second deposition station 26B and a third deposition station 26C on which the second and third material films are deposited, respectively. Because of this, the thickness of the material layer deposited on the receiving roller 22B is the sum of the thicknesses of the respective films deposited by the deposition station 26. In some embodiments, the deposition temperature, gas state composition, or both deposition temperature and gas state composition at each deposition station 26 varies from deposition station 26 to the resulting film properties such that the first deposition film, The next deposited film and the last deposited film are different.

Deposition chamber 18 may be configured with one or more in-situ measurement devices as it is formed during the CVD process to monitor the deposition layer. In one embodiment, the measurement device is located after each deposition station 26 to characterize the deposition layer.

2A shows web substrate 14 passing from left to right between heater 24 and manifold 30 for one of deposition stations 26 according to one embodiment. Each manifold 30 has a precursor port (port “A”) coupled to the source of the first precursor gas and a pair of precursor ports (port “B1”) coupled to the source of the second precursor gas. Port “B2”). The precursor gas ports are located between two pumping ports (“PUMP1” and “PUMP2”). Pumping ports are coupled to a discharge system for withdrawing precursor gases from the deposition chamber 18. Sources of precursor gases 28 may be located proximate or remotely to the deposition chamber 18. The material to be deposited during the CVD process can be changed by coupling the precursor ports to different precursor gas sources 28. Coupling may be performed manually at each manifold 30. Alternatively, reconstruction of precursor gases may be performed by remote activation of the gas distribution valve. As a specific example, one precursor gas may be a zinc compound and another precursor gas may be oxygen, where the deposited layer is a flat panel display, a light emitting diode (LED), an organic LED (OLED), and a solar cell. Aluminum, boron, indium, fluorine, silver, arsenic, antimony, phosphorus, nitrogen, lithium, magnesium, or gallium-doped zinc oxide materials used in the manufacture. To control bandgap and optical transmission wavelength blocking, adhesion, or other electrical properties, zinc oxide can be alloyed with various concentrations of Mg, Cd, Be, Te, S, and other elements.

During CVD processing, the web transport system moves the web substrate 14 through the deposition station 26 such that the proximal surface 34 of the web substrate 14 is adjacent to the precursor port and the pumping port. As used herein, the spacing between adjacent portions of the web substrate 14 and the ports of the deposition station is small, for example between 0.3 cm and 5 cm. Preferably, the spacing is between 0.5 cm and 1 cm. The first precursor gas flows up from port A and then flows along surface 34 through spaced regions in the substantial lamina flow toward each pumping port. The second precursor gas flows up from precursor port B1 and then flows to the left along surface 34 and mixes with a portion of the first precursor gas flowing to first pumping port PUMP1. Similarly, the second precursor gas flowing upward from precursor port B2 flows to the right along surface 34 and mixes with a portion of the first precursor gas flowing to second pumping port PUMP2.

The precursor gases react with one another in common flow regions before being removed through the pump port (PUMP). As such, there are two regions above the manifold 30 of each deposition station 26 where reactions occur and films are deposited. Increasing the flow rate of precursor gases results in an increase in deposition rate. Web substrate 14 moves continuously such that the entire web surface 34 passes through two regions of each deposition station 26 during the CVD process operation.

Advantageously, the precursor gases are limited to mixing near the surface 34 of the web substrate 14 before the reaction of the precursor gases is discharged to limit the area near the surface 34 and the surface 34 thereof. This prevents the reaction of precursor gases in other regions of the deposition chamber and avoids unwanted deposition and contamination.

An alternative configuration of manifold 40 in accordance with another embodiment of the present invention is shown in FIG. 2B. In this configuration, a first purge port “PURGE1” is provided between port A and port B1 and a second purge port “PURGE2” is provided between port A and port B2. Two additional purge ports “PURGE3” and “PURGE4” are placed on opposite sides of the pump port. Each purge port provides a carrier gas that does not react with the precursor gas. Carrier gas helps to build and maintain a uniform lamina flow of precursor gases. The reaction between the two precursor gases takes place in the region where they are mixed in a similar manner as described above with respect to FIG. 2A.

2C shows the configuration of a manifold 44 in accordance with another embodiment of the present invention. In this configuration, a single forge port “PURGE” is the center port of the manifold 44. The first pair of precursor gas ports A1 and A2 surround the purge port and provide a first precursor gas to the lamina flow. The second pair of precursor gas ports B1 and B2 surround the purge port and the first precursor gas ports A1 and A2 and provide a second precursor gas to the lamina flow.

3A is a block diagram of the manifolds of the deposition stations 26 of FIG. 1 integrated as a unitary structure in accordance with one embodiment of the present invention. Each manifold 30 is configured as described above with respect to FIG. 2A except that adjacent pump ports of adjacent manifolds 30 are combined as a single pump port. FIG. 3B is a top view of the web substrate 14 as it passes over the precursor gas ports and pump ports shown in FIG. 3A. Dotted rectangles indicate the location of the ports under the web substrate 14.

Each precursor port and each pump port has a rectangular shape with a length L slightly larger than the width W of the web substrate 14 such that the deposition layer extends to the edge of the web substrate 14. For each manifold 30, there is one region A + B where two precursor gases are mixed in the lamina flow to the left, and two precursor gases are in the lamina flow to the right. There is a second region A + B to be mixed. As the web substrate 14 moves from left to right, the deposition layer is gradually applied by each region of mixed precursor gases. Preferably, the flow rate of the gases present in each precursor gas port is fixed along the length L of the port, thereby minimizing the change in the ratio of precursor gases within the mixing region of the lamina flow and in the deposition layer. Minimize nonuniformity.

In the illustrated embodiment, each manifold 30 has a “B-A-B” precursor gas port sequence configuration, that is, precursor gas port B is disposed on both sides of a single precursor gas port A. In an alternate embodiment, one or more of the manifolds have an “A-B-A” precursor gas port configuration. In other words, for at least one of the manifolds, the sequence of precursor gases provided to the gas port is “inverted”.

4A and 4B are top and bottom perspective views, respectively, of one embodiment of the integrated deposition station module 50. 4C is a cross-sectional view of module 50. Module 50 includes three deposition stations 26 integrated as a single structure. The manifolds are configured in an arrangement similar to that shown in FIG. 3A, except that each pump port “PUMP” includes three closely spaced narrow slots instead of a single slot.

Each precursor gas port A or B is supplied by a pair of gas channels 54a or 54b respectively at the bottom of the module 50 perpendicular to the length of the ports. A single pump exhaust plenum 58 along the bottom of the module 50 is coupled at each of four locations to three slots of a single pump port. The narrow slots in the pump port allow the pressure gap to be maintained between the outside and inside of the pump outlet plenum 58. As a result, the pumping is uniform along the length of the slots, resulting in an improved lamina flow.

5 illustrates an inline CVD system 80 according to one embodiment of the invention. CVD system 80 includes a continuous substrate transport system for transporting individual substrates 92 through deposition chamber 84. For example, the individual substrates 92 may be a wafer or glass sheet, such as a semiconductor wafer. The CVD system 80 can be used to process semiconductor wafers in the manufacture of solar cells and devices.

Individual substrates 92 are loaded into the substrate transport system at atmospheric pressure. The substrate transport system includes a plurality of rollers that directly support the substrates 92 as they pass through the inline CVD system 80 while maintaining the desired position of each substrate 92 relative to the other substrate 92 and system components. 88). As an alternative, the carriers are held in transporting the substrates 92 with each carrier having one or more openings, each holding one or more substrates, each having a small lid which extends continuously around the opening or has a pin shape in the form of a pin. Used. For example, the carrier may be configured as one or more “picture frames,” wherein the substrate 92 is held in each frame by gravity. The substrates 92 are located on the rollers 88 or on the carriers using one or more known robotic systems or other automated mechanisms. In one embodiment, the rollers 88 are continuously operated in synchronization so that the transport rate of the substrates 92 is fixed throughout the inline CVD system. In another embodiment, the rollers 88 or groups of rollers 88 are controlled independently. For example, the rollers 88 in the load lock chambers 96 described below can be operated continuously or intermittently at one rotation rate, while the rollers in the deposition system are operated at different rotation rates. . The positions of the groups adjacent to the deposition stations 24 and the groups of rollers 88 in the load lock chambers 96 are placed close to each other such that a “hand off” for the next group of rollers 88 is achieved. It happens in a smooth and stable way. In other embodiments, the continuous substrate transport system uses other known mechanisms for controlling the position of the individual substrates 92 through the inline CVD system. For example, the continuous substrate transport system may include one or more controllable lead screw mechanisms.

Preferably, the walls of the deposition chamber 84 are kept clean from parasitic deposition by purge gases introduced at various locations in the chamber 84. Purge gases may also be used to keep the rollers 88 clean during the CVD process.

Individual substrates 92 pass through a first load lock chamber or isolation chamber 96A before entering the deposition chamber 84. The load lock chamber 96A along with the gate valve 98A provides a pressure interface between the atmospheric pressure at which the individual substrates 92 are loaded into the substrate feed mechanism and the vacuum environment of the deposition chamber 84. In one embodiment, load lock chamber 96A maintains a pressure below atmospheric pressure and above a vacuum level of deposition chamber 84. In another embodiment, load lock chamber 96A is coupled to a vacuum pump and a source of purge gas such that the pump and purge cycles can be repeated during CVD processing.

The substrate feed mechanism allows the deposition chamber 184 to pass through each substrate 92 in proximity to the plurality of deposition stations 26 and heaters 24 in a sequential manner similar to that described above for the web substrate 14 of FIG. 1. The individual substrates 92 are transported through. Deposition stations 26 are coupled to precursor gas sources 28 and are configured to provide at least two precursor gases in the lamina flow between each manifold and the surface of the individual substrate 92. Include them. As a result, precursor gases react to deposit a layer on the substrate surface. As an option, the precursor gases can be operated using an RF power source to allow a known PECVD process to be performed. The individual substrates 92 pass through the deposition stations 26 in a sequential manner, so that a layer of material of the desired thickness is deposited until the substrates pass the last deposition station 26C.

After completion of the deposition layer, the processed substrate 92 exits the deposition chamber 84 and enters an output load lock or isolation chamber 96B. Load lock chamber 96B and gate valve 98B perform as a pressure interface between atmospheric pressure at an unloading station and the vacuum environment of deposition chamber 84. In one embodiment, load lock chamber 96B operates at a pressure between atmospheric pressure and the pressure in deposition chamber 84. In another embodiment, load lock chamber 96B is coupled to a vacuum pump and a source of purge gas to allow the pump and purge cycles to be performed during CVD processing. After exiting the load lock chamber 96B, the individual substrates 92 are passed to an unloading station (not shown), which is removed from the continuous substrate feed mechanism using one or more robotic systems or automation mechanisms known herein.

In the above-described system embodiments and other embodiments of the inline CVD system according to the present invention, process parameters such as precursor gas flow rate, substrate temperature and transport rate, pump discharge rate, and deposition chamber pressure may be applied to the deposited material. It can be controlled to define thickness and other features. CVD systems can be suitable for a variety of applications and are suitable for single layer deposition in high throughput environments.

The inline CVD processing method according to one embodiment of the present teachings can be performed using the system of FIG. 1 or 5. The method provides a first flow A of first precursor gas A in a first direction along the surface of the substrate (eg, web substrate 14 or individual substrate 92) and on the surface of the substrate. Providing a second flow A ′ of the first precursor gas in the second direction accordingly. The first flow B of the second precursor gas is provided in a first direction along the surface of the substrate and mixed with the first flow A of the first precursor gas. The second flow B ′ of the second precursor gas is provided in a second direction along the surface of the substrate and mixed with the second flow A ′ of the first precursor gas. The substrate is first exposed to the first mixing flows A and B of the first and second precursor gases and the second mixing flows A 'and B' of the first and second precursor gases. It is transported continuously in a second direction to be exposed.

Preferably, the substrate is delivered at a fixed rate through a CVD process. In some embodiments, the substrate is heated during the deposition process. In other embodiments, the method also includes providing a first flow of carrier gas in a first direction and providing a second flow of carrier gas in a second direction. The carrier gas includes a gas that does not react with the precursor gases and helps maintain a uniform lamina flow of precursor gases over a portion of the surface containing the deposition layer.

The inline CVD method of the present invention, in which materials are deposited onto substrates in an incremental and sequential manner, allows for high throughput of CVD processing web substrates or large capacity output of CVD processing individual substrates. The composition of the film deposited at each deposition station 26 is substantially the same as the films deposited at other deposition stations 26. Various process parameters such as transport rate, precursor gas flow rate, and substrate temperature can be controlled to achieve a high quality deposition layer of the desired thickness.

Another method for inline CVD processing in accordance with embodiments of the present teachings may be performed to fabricate devices such as solar cells having the device structure illustrated in FIG. 6. Device 100 includes substrate 104, which may be a separate substrate or a flexible web substrate. By way of example, the individual substrates may be glass substrates or wafers, and the web substrates may be polyimide or metal foil. The device 100 may include a metal layer 108, such as a molybdenum layer, an absorbing layer 112, such as a copper indium gallium diselenide (CIGS) layer, a buffer layer (or junction partner) 116, a window layer 120, and a transparent conductive layer. Further comprises layer 124. For example, the buffer layer 116 may be a cadmium sulfide (CdS) layer, a zinc sulfide (ZnS) layer, or an indium sulfide (InS) layer, and the window layer 120 may be an intrinsic zinc oxide (ZnO) layer and may be transparent. Conductive layer 124 may be a doped ZnO layer, such as an indium tin oxide layer or an aluminum-doped zinc oxide (AZO) layer, a boron-doped zinc oxide (BZO) layer, or a gallium-doped zinc oxide (GZO) layer.

Using conventional techniques, buffer layer 116 is a thin film layer (eg, 50 nm) typically produced using a chemical solution deposition (CBD) process, thin film ZnO layer 120 (eg, 50 nm) and Transparent conductive layer 124 is deposited using CVD processes. More specifically, the device under manufacture goes from the CBD process to the first CVD process and the second CVD process. These techniques are generally time intensive as the CBD process step and the two CVD process steps are performed independently.

According to embodiments of a CVD method for inline fabrication of a device based on the principles of the present invention, the process steps of creating a buffer layer, a window layer, and a transparent conductive layer are performed sequentially in a common vacuum environment of the deposition chamber. CBD deposition of the buffer layer is unnecessary and three separate layers are deposited without the need to be transported between different chambers. Because of this, there is no need to return to the atmosphere between different CVD deposition processes.

7 illustrates one embodiment of an inline CVD system 128 for the fabrication of solar cell devices for the web substrate 14. Inline CVD system 128 includes similar components as described above for inline CVD system 10 of FIG. 1, but the group of deposition stations 26 used to create a single material layer is a single deposition module 132. Is represented by. For example, each deposition module 132 may be coupled to a source of precursor gases in the precursor gas module 136 to deposit one or more manifolds, such as the manifold of FIGS. 4A-4C, to deposit a particular material layer. It may include. Each deposition module 132 deposits a material layer that is different from the material layers deposited by other deposition modules 132. The heating module 140 is located proximate the web substrate 14 opposite each manifold or manifold group in each deposition module 132 to heat the web substrate 14 to the desired process temperature.

In the illustrated embodiment, the system 128 is configured to manufacture a device similar to the device 100 of FIG. 6. More specifically, the first deposition module 132A is configured to deposit a CdS buffer layer, the second deposition module 132B is configured to deposit an intrinsic ZnO layer, and the third deposition module 132C is configured to deposit an AZO layer. It is composed. The number of manifolds, precursor gas flow rate for the manifold, and web substrate temperature may vary between deposition modules 132 to achieve the desired thickness of each layer deposited by each deposition module 132. For example, the third deposition module 132C is shown to have a greater length than the two first deposition modules 132A and 132B due to the substantially larger thickness of the AZO layer compared to the CdS buffer layer and the intrinsic ZnO layer. .

The system 128 may differ by modifying precursor gases provided to one or more of the deposition modules 132 and modifying other process parameters such as web transport rate, substrate temperature, manifold pump discharge rate, and deposition chamber pressure. It can be reconfigured to produce device structures with material layers. As specific examples, another CIGS solar cell device may be fabricated using a first deposition module 132A configured to deposit a ZnS layer or an InS layer and a third deposition module 132C configured to deposit a GZO layer or a BZO layer. . System 128 may be configured to produce other device layer structures such as a barrier layer (eg, SiO ₂ or Al ₂ O ₃ ) between the substrate and the bag (molybdenum) contacts. This structure on the glass plate substrate prevents uncontrollable sodium flow from the glass. Thereafter, a controlled amount of sodium is produced on top of the barrier layer. System 128 may be suitable for producing structures having ZnO fluoride or tin oxide (SnO ₂ ) as a transparent conductive layer for amorphous silicon.

8 shows an inline CVD system 140 suitable for the fabrication of a solar cell device for individual substrates 92. The inline CVD system 140 includes similar components as described above for the inline CVD system 80 of FIG. 5, but each group of deposition stations 26 depositing a common material is connected to a single deposition module 132. Is represented by. System 140 is configured such that individual substrates 92 contain three layers similar to those deposited on web substrate 14 in system 128 of FIG. 7. The number of manifolds per deposition station 132, the type and flow rate of precursors, substrate temperature, transport rate and other process parameters can be selected such that different material layers and layer thicknesses can be obtained.

Advantageously, the systems 128 and 140 of FIGS. 7 and 8 can both allow devices to be created by continuous CVD deposition processes occurring in a single deposition chamber. As a result, manufacturing time and cost are reduced compared to conventional techniques used to create similar devices.

9 is a flow diagram illustrating one embodiment of an inline CVD method 200 for fabricating a device. 6 and 8, the method 200 includes transporting the substrate 92 (104 in FIG. 6) at a fixed rate through the deposition chamber 84 (step 210). The substrate 92 may include the metal layer 108 and the absorber layer 112 shown in FIG. 6. A buffer layer 116 is deposited on the substrate 92 while passing through the first deposition module 132A (step 220). The window layer 120 is deposited on the buffer layer 116 (step 230), the substrate is transported through the next deposition module 132B, and the transparent conductive layer 124 is deposited on the window layer 120 (step 240). The substrate 92 is transported through the third deposition module 132C. The buffer layer 116, window layer 120, and transparent conductive layer 124 may be any of a variety of materials as described above with respect to fabrication using the inline CVD system of FIGS. 7 and 8.

Although method 200 is described with respect to the processing of individual substrates 92 in accordance with system 140 of FIG. 8, other embodiments of an inline CVD method of fabricating a device in accordance with the principles of the present invention will be appreciated. . For example, a complementary embodiment to the method 200 of FIG. 9 relates to the deposition of devices on a web substrate using, for example, the system 128 of FIG. 7.

While the invention has been shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (34)

An inline chemical vapor deposition method for manufacturing a device,
Transporting a substrate through a deposition chamber having a vacuum environment and a first deposition module, a second deposition module, and a third deposition module;
Depositing a buffer layer on the substrate during transportation of the substrate through the first deposition module;
Depositing a window layer on the buffer layer during transportation of the substrate through the second deposition module; And
Depositing a transparent conductive layer on the window layer during transportation of the substrate through the third deposition module
Inline chemical vapor deposition method comprising a. The method of claim 1,
Each deposition module including at least one deposition station having a manifold having a plurality of ports coupled to a plurality of precursor gas sources. The method of claim 1,
And the substrate is transported through the deposition chamber at a fixed rate. The method of claim 1,
And the substrate comprises a metal layer and an absorbing layer prior to transportation through the first deposition module. 5. The method of claim 4,
And the absorber layer comprises a copper indium gallium diselenide layer. The method of claim 1,
Wherein said substrate is a separate substrate. The method according to claim 6,
Wherein said individual substrate is a glass substrate. The method according to claim 6,
Wherein said individual substrate is a wafer. The method according to claim 6,
The transport of the individual substrates through the deposition chamber includes transporting a plurality of individual substrates through the deposition chamber, wherein at least one of the individual substrates is simultaneously transported through each of the deposition modules. . The method of claim 1,
And the substrate is a web substrate. The method of claim 1,
Gas flows between the first deposition module and the second deposition module and between the second deposition module and the third deposition module to isolate the first deposition module, the second deposition module, and the third deposition module from each other. Inline chemical vapor deposition method further comprising the step. 3. The method of claim 2,
The ports of each manifold include a first precursor port, a pair of second precursor ports, and a pair of pumping ports, the first precursor ports being disposed between the second precursor ports and And the pair of second precursor ports are disposed between the pumping ports, wherein the first precursor port and the pair of second precursor ports are a first precursor gas source and a second precursor gas source. Each of the pumping ports is coupled to an emission system and configured to exhaust the first precursor gas and the second precursor gas. The method of claim 1,
Wherein the buffer layer comprises one of a cadmium sulfide layer, a zinc sulfide layer, and an indium sulfide layer. The method of claim 1,
And the window layer comprises an intrinsic zinc oxide layer. The method of claim 1,
And the transparent conductive layer comprises one of an aluminum-doped zinc oxide layer, a gallium-doped zinc oxide layer, a boron-doped zinc oxide layer, and an indium tin oxide layer. An inline chemical vapor deposition method for manufacturing a device,
Transporting a substrate having a metal layer and an absorbing layer at a fixed rate through a deposition chamber having a vacuum environment and a first deposition module, a second deposition module, and a third deposition module, each of the deposition modules comprising a first precursor port, a At least one deposition station having a pair of second precursor ports, and a manifold comprising a pair of pumping ports, the first precursor ports being disposed between the second precursor ports, A pair of second precursor ports are disposed between the pumping ports, and the first precursor port and the pair of second precursor ports are coupled to a first precursor gas source and a second precursor gas source, respectively. The pumping ports are coupled to a discharge system and configured to discharge the first precursor gas and the second precursor gas;
Depositing a buffer layer on the substrate during transportation of the substrate through the first deposition module;
Depositing a window layer on the buffer layer during transportation of the substrate through the second deposition module; And
Depositing a transparent conductive layer on the window layer during transportation of the substrate through the third deposition module
Including, inline chemical vapor deposition method. 17. The method of claim 16,
And the absorber layer comprises a copper indium gallium diselenide layer. 17. The method of claim 16,
Wherein said substrate is a separate substrate. 19. The method of claim 18,
Wherein said individual substrate is a glass substrate. 19. The method of claim 18,
Wherein said individual substrate is a wafer. 19. The method of claim 18,
The transport of the individual substrates through the deposition chamber includes transporting a plurality of individual substrates through the deposition chamber, wherein at least one of the individual substrates is simultaneously transported through each of the deposition modules. . 17. The method of claim 16,
Wherein the substrate is a web substrate. 17. The method of claim 16,
Wherein the buffer layer comprises one of a cadmium sulfide layer, a zinc sulfide layer, and an indium sulfide layer. 17. The method of claim 16,
And the window layer comprises an intrinsic zinc oxide layer. 17. The method of claim 16,
And the transparent conductive layer comprises one of an aluminum-doped zinc oxide layer, a gallium-doped zinc oxide layer, a boron-doped zinc oxide layer, and an indium tin oxide layer. Inline chemical vapor deposition system,
A deposition chamber;
A continuous transport system for transporting the substrate along a path through the deposition chamber;
A first deposition module disposed in a path within the deposition chamber and having at least one deposition station for depositing a buffer layer on the substrate;
A second deposition module disposed in a path in the deposition chamber and having at least one deposition station for depositing a window layer in the buffer layer; And
A third deposition module disposed in a path within the deposition chamber and having at least one deposition station for depositing a transparent conductive layer on the window layer
/ RTI >
Each of the deposition modules comprises at least one deposition station having a manifold comprising a first precursor port, a pair of second precursor ports, and a pair of pumping ports, wherein the first precursor ports comprise: Disposed between second precursor ports, wherein the pair of second precursor ports are disposed between the pumping ports, and the first precursor port and the pair of second precursor ports are each first free A cursor gas source and a second precursor gas source, wherein the pumping ports are coupled to an emission system and configured to discharge the first precursor gas and the second precursor gas. The method of claim 26,
Wherein said substrate is a separate substrate. 28. The method of claim 27,
Wherein said individual substrate is a glass substrate. 28. The method of claim 27,
Wherein said individual substrate is a wafer. 28. The method of claim 27,
And the continuous delivery system is configured to transport a plurality of individual substrates along the path through the deposition chamber, wherein at least one of the individual substrates is simultaneously transported through each of the deposition modules. The method of claim 26,
And the substrate is a web substrate. The method of claim 26,
And the at least one deposition station of the first deposition module is configured to deposit one of a cadmium sulfide layer, a zinc sulfide layer, and an indium sulfide layer to the substrate. The method of claim 26,
And the at least one deposition station of the second deposition module is configured to deposit an intrinsic zinc oxide layer. The method of claim 26,
The at least one deposition station of the third deposition module is configured to deposit one of an aluminum-doped zinc oxide layer, a gallium-doped zinc oxide layer, a boron-doped zinc oxide layer, and an indium tin oxide layer. Deposition system.

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