Abstract: Methods and apparatus having a gradient spacing created between a substrate support assembly and a gas distribution plate for depositing a silicon film for solar cell applications are provided. In one embodiment, an apparatus for depositing films for solar cell applications may include a processing chamber, a substrate support disposed in the processing chamber and configured to support a quadrilateral substrate thereon, and a gas distribution plate disposed in the processing chamber above the substrate support, wherein a bottom surface of the gas distribution plate has a perimeter that includes edges and corners, and wherein the corners of the gas distribution plate are closer to the substrate support than the edges of the gas distribution plate.

Abstract: Embodiments of the present invention provide methods for depositing a nitrogen-containing material on large-sized substrates disposed in a processing chamber. In one embodiment, a method includes processing a batch of substrates within a processing chamber to deposit a nitrogen-containing material on a substrate from the batch of substrates, and performing a seasoning process at predetermined intervals during processing the batch of substrates to deposit a conductive seasoning layer over a surface of a chamber component disposed in the processing chamber. The chamber component may include a gas distribution plate fabricated from a bare aluminum without anodizing. In one example, the conductive seasoning layer may include amorphous silicon, doped amorphous silicon, doped silicon, doped polysilicon, doped silicon carbide, or the like.

Abstract: A method and apparatus for forming a thin film transistor is provided. A gate dielectric layer is formed, which may be a bilayer, the first layer deposited at a low rate and the second deposited at a high rate. In some embodiments, the first dielectric layer is a silicon rich silicon nitride layer. An active layer is formed, which may also be a bilayer, the first active layer deposited at a low rate and the second at a high rate. The thin film transistors described herein have superior mobility and stability under stress.

Abstract: Embodiments of the invention generally provide a mixing block for mixing precursors and/or cleaning agent which has the advantage of maintaining the temperature and improving the mixing effect of the precursors, cleaning agent or the mixture thereof to eliminate the substrate-to-substrate variation, thereby providing improved process uniformity.

Abstract: Embodiments of a gas diffuser plate for distributing gas in a processing chamber are provided. The gas distribution plate includes a diffuser plate having an upstream side and a downstream side, and a plurality of gas passages passing between the upstream and downstream sides of the diffuser plate. The gas passages include hollow cathode cavities at the downstream side to enhance plasma ionization. The depths, the diameters, the surface area and density of hollow cathode cavities of the gas passages that extend to the downstream end can be gradually increased from the center to the edge of the diffuser plate to improve the film thickness and property uniformity across the substrate. The increasing diameters, depths and surface areas from the center to the edge of the diffuser plate can be created by bending the diffuser plate toward downstream side, followed by machining out the convex downstream side. Bending the diffuser plate can be accomplished by a thermal process or a vacuum process.

Abstract: An apparatus and method for supporting a substantial center portion of a gas distribution plate is disclosed. At least one support member is capable of engaging and disengaging the diffuser with a mating connection without prohibiting flow of a gas or gases through the diffuser and is designed to provide vertical suspension to a diffuser that is supported at its perimeter, or capable of supporting the diffuser without a perimeter support. In one aspect, the at least one support member is a portion of a gas delivery conduit and in another embodiment is a plurality of support members separated from the gas delivery conduit. The at least one support member is capable of translating vertical lift, or vertical compression to a center area of the diffuser. A method and apparatus for controlling gas flow from the gas delivery conduit to the gas distribution plate is also disclosed.

Abstract: Embodiments of a gas distribution plate for distributing gas in a processing chamber are provided. In one embodiment, a gas distribution assembly for a plasma processing chamber comprises a diffuser plate with gas passages passing between its upstream and downstream sides and hollow cathode cavities at the downstream side of the gas passages. The downstream side of the diffuser plate has a curvature to improve the thickness uniformity and film property uniformity of thin films deposited by PECVD, particularly SiN and amorphous silicon films. The curvature is preferably described by an arc of a circle or ellipse, the apex thereof located at the center point of the diffuser plate. In one aspect, the hollow cathode cavity volume density, surface area density, or the cavity density of the diffuser increases from the center of the diffuser to the outer edge. Methods for manufacturing such a diffuser plate are also provided.

Abstract: A method for preventing particle contamination within a processing chamber is disclosed. Preheating the substrate within the processing chamber may cause a thermophoresis effect so that particles within the chamber that are not adhered to a surface may not come to rest on the substrate. One method to increase the substrate temperature is to plasma load the substrate. Plasma loading comprises providing an inert gas plasma to the substrate to heat the substrate. Another method to increase the substrate temperature is high pressure loading the substrate. High pressure loading comprises heating the substrate while increasing the chamber pressure to between about 1 Torr and about 10 Torr. By rapidly increasing the substrate temperature within the processing chamber prior to substrate processing, particle contamination is less likely to occur.

Abstract: Methods for forming a microcrystalline silicon layer in a thin film transistor structure are provided. In one embodiment, a method for forming a microcrystalline silicon layer includes providing a substrate in a processing chamber, supplying a first gas mixture having a hydrogen containing gas to a silicon containing gas flow rate ratio greater than about 200:1 into the processing chamber, maintaining a first process pressure greater than about 6 Torr in the processing chamber to deposit a first microcrystalline silicon containing layer in presence of a plasma formed from the first gas mixture, supplying a second gas mixture into the processing chamber, and maintaining a second process pressure less than about 5 Torr in the processing chamber to deposit a second microcrystalline silicon containing layer in presence of a plasma formed from the second gas mixture.

Abstract: Embodiments of a gas diffuser plate for distributing gas in a processing chamber are provided. The gas distribution plate includes a diffuser plate having an upstream side and a downstream side, and a plurality of gas passages passing between the upstream and downstream sides of the diffuser plate. The gas passages include hollow cathode cavities at the downstream side to enhance plasma ionization. The depths, the diameters, the surface area and density of hollow cathode cavities of the gas passages that extend to the downstream end can be gradually increased from the center to the edge of the diffuser plate to improve the film thickness and property uniformity across the substrate. The increasing diameters, depths and surface areas from the center to the edge of the diffuser plate can be created by bending the diffuser plate toward downstream side, followed by machining out the convex downstream side. Bending the diffuser plate can be accomplished by a thermal process or a vacuum process.

Abstract: Abnormal conditions within an RF-powered plasma process chamber are detected by detecting whether the frequency of a variable-frequency RF power supply moves outside established lower and upper limits. In a first aspect, a first pair of lower and upper limits are established as a function of the frequency of the power supply sampled after a new process step begins or after a sample control signal changes state. In a second aspect, a second pair of lower and upper limits are not adapted to the frequency of the power supply. Both aspects preferably are used together to detect different occurrences of abnormal conditions.

Abstract: A multistage amplifying circuit includes a first amplifying circuit that either samples a first analog voltage input or amplifies a difference between the first analog voltage and a first digital voltage converted from the first analog voltage, in response to a control signal. A second amplifying circuit either samples a second analog voltage input or amplifies a difference between the second analog voltage and a second digital voltage converted from the second analog voltage, in response to the control signal. A common amplifier receives output voltages of the first amplifying circuit and the second amplifying circuit and either resets the output voltage of the first amplifying circuit and determines an output voltage by using the second amplifying circuit, or resets the output voltage of the second amplifying circuit and determines an output voltage by using the first amplifying circuit, in response to the control signal.

Abstract: The present invention generally relates to a method for flexible process condition monitoring. In a process that utilizes RF power, the RF power may be applied at different levels during different points in the process. Software may be programmed to facilitate the monitoring of the different points in the process so that the acceptable deviation range of the RF power for each point in the process may be set to different values. For example, one phase of the process may permit a greater range of RF power deviation while a second phase may be much more particular and permit very little deviation. By programming software to permit each phase of the process to be uniquely monitored, a more precise RF process may be obtained.

Abstract: Embodiments disclosed herein generally relate to a PECVD apparatus. When the RF power source is coupled to the electrode at multiple locations, the current and voltage may be different at the multiple locations. In order to ensure that both the current and voltage are substantially identical at the multiple locations, an RF bridge assembly may be coupled between the multiple locations at a location just before connection to the electrode. The RF bridge assembly substantially equalizes the voltage distribution and current distribution between multiple locations. Therefore, a substantially identical current and voltage is applied to the electrode at the multiple locations.

Abstract: An electrical ground (36) of an RF impedance matching network (33) is connected to a connection area (50) on the grounded chamber cover (18) of a plasma chamber. The connection area is offset away from the center of the chamber cover toward a workpiece passageway (20). Alternatively, an RF power supply (30) has an electrically grounded output (32) that is connected to a connection area (52) on the chamber cover having such offset. Alternatively, an RF transmission line (37) has an electrically grounded conductor (39) that is connected between a grounded output of an RF power supply and a connection area (52) on the chamber cover having such offset.

Abstract: An ?-SiNx:H gate dielectric film deposited over a substrate surface having a surface area larger than 100 cm×100 cm, wherein said ?-SiNx:H gate dielectric film exhibits a film thickness which varies by less than about 20% over said surface area, a film density which varies by less than about 17% over said surface area, and wherein said film exhibits a Si—H bonded structure content of less than about 15 atomic % over said surface area.

Abstract: Abnormal conditions within an RF-powered plasma process chamber are detected by detecting whether the frequency of a variable-frequency RF power supply moves outside established lower and upper limits. In a first aspect, a first pair of lower and upper limits are established as a function of the frequency of the power supply sampled after a new process step begins or after a sample control signal changes state. In a second aspect, a second pair of lower and upper limits are not adapted to the frequency of the power supply. Both aspects preferably are used together to detect different occurrences of abnormal conditions.

Abstract: A multistage amplifying circuit includes a first amplifying circuit that either samples a first analog voltage input or amplifies a difference between the first analog voltage and a first digital voltage converted from the first analog voltage, in response to a control signal. A second amplifying circuit either samples a second analog voltage input or amplifies a difference between the second analog voltage and a second digital voltage converted from the second analog voltage, in response to the control signal. A common amplifier receives output voltages of the first amplifying circuit and the second amplifying circuit and either resets the output voltage of the first amplifying circuit and determines an output voltage by using the second amplifying circuit, or resets the output voltage of the second amplifying circuit and determines an output voltage by using the first amplifying circuit, in response to the control signal.

Abstract: We have discovered that adding H2 to a precursor gas composition including SiH4, NH3, and N2 is effective at improving the wet etch rate and the wet etch rate uniformity across the substrate surface of a-SiNx:H films which are deposited on a substrate by PECVD. Wet etch rate is an indication of film density. Typically, the lower the wet etch rate, the denser the film. The addition of H2 to the SiH4/NH3/N2 precursor gas composition did not significantly increase the variation in deposited film thickness across the surface of the substrate. The uniformity of the film across the substrate enables the production of flat panel displays having surface areas of 25,000 cm2 and larger.

Abstract: Embodiments of the disclosure generally provide a method and apparatus for processing a substrate in a vacuum process chamber. In one embodiment a vacuum process chamber is provided that includes a chamber body and lid disposed on the chamber body. A blocker plate is coupled to the lid and bounds a staging plenum therewith. A gas distribution plate is coupled to the lid. The gas distribution plate separates a main plenum defined between the gas distribution plate and the blocker plate from a process volume defined within the chamber body. The gas distribution plate and the blocker plate define a spacing gradient therebetween which influences mixing of gases within the main plenum.