Abstract: A method wherein a thermal gradient over a substrate enhances Chemical Vapor Deposition (CVD) at low pressures. An upper heat source is positioned above the substrate and a lower heat source is positioned below the substrate. The upper and lower heat sources are operated to raise the substrate temperature to 400-700° and cause a heat gradient of 100-200° C. between the upper and lower heat sources. This heat gradient causes an increase in the deposition rate for a given reactant gas flow rate and chamber pressure. The preferred parameters for implementation of the present invention for poly crystalline silicon deposition include the temperature of the upper heat source 100-200° C. above the lower heat source, a substrate temperature in the range of 400-700° C., a reactant gas pressure between 250 and 1000 mTorr, and a gas flow rate of 200-800 sccm. The substrate is rotated, with 5 RPM being a typical rate.

Abstract: A chemical vapor deposition reactor including a wafer boat with a vertical stack of horizontally oriented susceptors serving as thermal plates and each having pins extending upward for suspending a wafer between a pair of susceptors. Reactant gas injector and exhaust apparatus are positioned to concentrate a forceful supply of reactant gas across each wafer at a speed in excess of 10 cm/sec. The pressure is held in the range of 0.1 to 5,000 mTorr. The forceful gas flow avoids gas depletion effects, thinning the boundary layer and resulting in faster delivery of reactants to substrate surfaces, resulting in surface rate reaction limited operation. A plurality of individually controllable heaters are spaced vertically around the sides of the boat. Temperature sensors monitor the temperature along the boat height and provide input to a controller for adjusting the heater drive to optimize the temperature uniformity.

Abstract: A method for high rate silicon nitride deposition at low pressures, including a method of operating a CVD reactor providing a novel combination of wafer temperature, gas flow and chamber pressure resulting in both rapid deposition and a uniform, smooth film surface. According to the method, a wafer is placed in a vacuum chamber wherein a reactant gas flow of silane and ammonia is directed in parallel with the wafer surface via a plurality of temperature controlled gas injectors, the gas being confined to a narrow region above the wafer. The gas is injected at a high velocity, causing the deposition rate to be limited only by the rate of delivery of unreacted gas to the wafer surface and the rate of removal of reaction byproducts. The high velocity gas stream passing across the wafer has the effect of thinning the layer adjacent the wafer surface containing reaction by-products, known as the “boundary layer,” resulting in faster delivery of the desired reactant gas to the wafer surface.

Abstract: A method wherein a thermal gradient over a substrate enhances Chemical Vapor Deposition (CVD) at low pressures. An upper heat source is positioned above the substrate and a lower heat source is positioned below the substrate. The upper and lower heat sources are operated to raise the substrate temperature to 400-700° and cause a heat gradient of 100-200° C. between the upper and lower heat sources. This heat gradient causes an increase in the deposition rate for a given reactant gas flow rate and chamber pressure. The preferred parameters for implementation of the present invention for poly crystalline silicon deposition include the temperature of the upper heat source 100-200° C. above the lower heat source, a substrate temperature in the range of 400-700° C., a reactant gas pressure between 250 and 1000 mTorr, and a gas flow rate of 200-800 sccm. The substrate is rotated, with 5 RPM being a typical rate.

Abstract: A semiconductor wafer or flat panel display process chamber for thermally driven, chemical vapor deposition, and/or plasma enhanced chemical vapor deposition processes includes a chamber for loading/unloading the substrate to be processed, and another chamber for processing. The substrate is heated with multiple zone radiant heaters arranged around the processing chamber to provide uniform heating. Process gases are injected into and exhausted in a cross flow fashion. The chamber may be used for plasma processing. Shield plates prevent deposition of reactant species on chamber walls, and also serve to diffuse heat uniformly the chamber.

Abstract: A multiwafer chemical vapor deposition (CVD) reactor providing improved material deposition uniformity through use of improved gas injection and exhaust apparatus. The reactor includes a wafer boat for supporting a vertical stack of wafers, spaced apart for passage of a reactant gas. A preferred embodiment of the gas injector is in the form of a vertically oriented body having at a first end a gas inlet, and extending inward from a wall of the reactor towards the wafer boat, terminating in a widened injector outlet. The injector body and outlet extend vertically a distance approximating the height of the wafer boat, and the outlet is widened to provide an improved flow of gas across the wafer. A face of the injector outlet contains a plurality of gas ejecting holes, arranged to provide a uniform supply of reactant gas over each wafer surface.

Abstract: A method and apparatus for improved CVD process results uses tunable temperature controlled gas injectors. The design is suited to single wafer and multiple wafer CVD process chambers.

Abstract: A plasma enhanced chemical vapor deposition (PECVD) system having an upper chamber for performing a plasma enhanced process, and a lower chamber having an access port for loading and unloading wafers to and from a wafer boat. The system includes apparatus for moving the wafer boat from the upper chamber to the lower chamber. The wafer boat includes susceptors for suspending wafers horizontally, spaced apart in a vertical stack. An RF plate is positioned in the boat above each wafer for generating an enhanced plasma. An RF connection is provided which allows RF energy to be transmitted to the RF plates while the wafer boat is rotated. Apparatus for automatic wafer loading and unloading is provided, including apparatus for lifting each wafer from its supporting susceptor and a robotic arm for unloading and loading the wafers.

Abstract: A method for high rate silicon nitride deposition at low pressures, including a method of operating a CVD reactor providing a novel combination of wafer temperature, gas flow and chamber pressure resulting in both rapid deposition and a uniform, smooth film surface. According to the method, a wafer is placed in a vacuum chamber wherein a reactant gas flow of silane and ammonia is directed in parallel with the wafer surface via a plurality of temperature controlled gas injectors, the gas being confined to a narrow region above the wafer. The gas is injected at a high velocity, causing the deposition rate to be limited only by the rate of delivery of unreacted gas to the wafer surface and the rate of removal of reaction byproducts. The high velocity gas stream passing across the wafer has the effect of thinning the layer adjacent the wafer surface containing reaction by-products, known as the “boundary layer,” resulting in faster delivery of the desired reactant gas to the wafer surface.

Abstract: A plasma enhanced chemical vapor deposition (PECVD) system having an upper chamber for performing a plasma enhanced process, and a lower chamber having an access port for loading and unloading wafers to and from a wafer boat. The system includes apparatus for moving the wafer boat from the upper chamber to the lower chamber. The wafer boat includes susceptors for suspending wafers horizontally, spaced apart in a vertical stack. An RF plate is positioned in the boat above each wafer for generating an enhanced plasma. An RF connection is provided which allows RF energy to be transmitted to the RF plates while the wafer boat is rotated. Apparatus for automatic wafer loading and unloading is provided, including apparatus for lifting each wafer from its supporting susceptor and a robotic arm for unloading and loading the wafers.

Abstract: A method for high rate silicon deposition at low pressures, including a method of operating a CVD reactor having a high degree of temperature and gas flow uniformity, the method of operation providing a novel combination of wafer temperature, gas flow and chamber pressure. According to the method, a substrate is placed in a vacuum chamber wherein a reactant gas is provided at a high velocity in parallel with the substrate via a plurality of temperature controlled gas injectors providing a condition wherein the deposition rate is only limited by the rate of delivery of unreacted gas to the substrate surface and the rate of removal of reaction byproducts. The novel combination of process conditions moves the reaction at the wafer surface into the regime where the deposition rate exceeds the crystallization rate, resulting in very small crystal growth and therefore a very smooth polysilicon film with a surface roughness on the order of 5-7 nm for films 2500 angstroms thick.

Abstract: High rate silicon dioxide deposition at low pressures, including a method of depositing silicon dioxide providing a high rate of deposition at a low process chamber pressure, yielding a film with excellent uniformity and with an absence of moisture inclusion and gas phase nucleation. According to the method, a wafer is placed in a reaction chamber wherein a reactant gas flow of silane and oxygen is directed in parallel with the wafer via a plurality of temperature-controlled gas injectors, and confined to a narrow region above the wafer. The gas is injected at a high velocity resulting in the deposition rate being limited only by the rate of delivery of unreacted gas to the wafer surface and the rate of removal of by-products. The high velocity gas stream passing across the wafer has the effect of thinning the layer adjacent the wafer surface containing reaction by-products, known as the “boundary layer,” which results in faster delivery of the desired reactant gas to the wafer surface.

Abstract: A CVD reactor includes a vacuum chamber having first and second thermal plates disposed therein and two independently-controlled multiple-zone heat sources disposed around the exterior thereof. The first heat source has three zones and the second heat source has two zones. A wafer to be processed is positioned below the first thermal plate and immediately above the second thermal plate, thereby being indirectly heated from above by the first heat source via the first thermal plate and indirectly heated from below by the first zone of the second heat source via the second thermal plate. A thermal ring plate which laterally surrounds the edge of the wafer absorbs heat energy emitted from the second zone of the second heat source and heats the outer edge of the wafer.

Abstract: Changes in the state of a chemical reactant, particularly a resin used for purifying gases, are measured by directing a beam of light through the reactant and detecting changes in the light transmissivity of the reactant as the reactant goes from a first state to a second state.

Abstract: An apparatus is provided for obtaining very high quality films by chemical vapor deposition in situations where the deposition is mass transport limited. In accordance with the preferred embodiments, there is provided a vacuum housing which is actively cooled to a temperature below which deposition occurs, while at the same time the wafers are being heated to cause deposition at the wafer surfaces. Also provided are mixing chamber systems to ensure that reactant gases are well mixed and distributed evenly over each wafer surface. Mass transport control is further enhanced by providing an exhaust manifold which scavenges reactant gases from locations distributed throughout the system to achieve an even exhaust. Also provided is a method for depositing silicon-rich tungsten silicides using the above apparatus.

Abstract: A composite film is provided which has a first layer of WSi.sub.x, where x is greater than 2, over which is disposed a second layer of a tungsten complex consisting substantially of tungsten with a small amount of silicon therein, typically less than 5%. Both layers are deposited in situ in a cold wall chemical vapor deposition chamber at a substrate temperature of between 500.degree. and 550.degree. C.. Before initiating the deposition process for these first and second layers, the substrate onto which they are to be deposited is first plasma etched with NF.sub.3 as the reactant gas, then with H.sub.2 as the reactant gas, both steps being performed at approximately 100 to 200 volts self-bias. WSi.sub.

Abstract: In a chemical vapor deposition apparatus for coating semiconductor wafers, the wafer is held face down in the reaction chamber. A radiant heat source above the wafer and outside the reaction chamber. The wafer is held on a ring chuck by means of a retractable clamp heats the wafer from its backside to a temperature in excess of 1000.degree. C. rapidly. The radiant heat source includes cylindrical lamps placed in a radial pattern to improve heating uniformity. In the selective tungsten process the temperature of the wafer is raised from ambient to about 600.degree. C. while flowing process gases. At the upper temperature range the heating source can be rapidly cycled on and off to improve the uniformity of coating.

Abstract: A composite film is provided which has a first layer of WSi.sub.x, where x is greater than 2, over which is disposed a second layer of a tungsten complex consisting substantially of tungsten with a small amount of silicon therein, typically less than 5%. Both layers are deposited in situ in a cold wall chemical vapor deposition chamber at a substrate temperature of between 500.degree. and 550.degree. C. Before initiating the deposition process for these first and second layers, the substrate onto which they are to be deposited is first plasma etched with NF.sub.3 as the reactant gas, then with H.sub.2 as the reactant gas, both steps being performed at approximately 100 to 200 volts self-bias. WSi.sub.

Abstract: An apparatus is provided for obtaining very high quality films by chemical vapor deposition in situations where the deposition is mass transport limited. In accordance with the preferred embodiments, there is provided a vacuum housing which is actively cooled to a temperature below which deposition occurs, while at the same time the wafers are being heated to cause deposition at the wafer surfaces. Also provided are mixing chamber systems to ensure that reactant gases are well mixed and distributed evenly over each wafer surface. Mass transport control is further enhanced by provided an exhaust manifold which scavenges reactant gases from locations distributed throughout the system to achieve an even exhaust. Also provided is a method for depositing silicon-rich tungsten silicides using the above apparatus.

Abstract: A CVD reactor includes a vacuum chamber having first and second thermal plates disposed therein and two independently-controlled multiple-zone heat sources disposed around the exterior thereof. The first heat source has three zones and the second heat source has two zones. A wafer to be processed is positioned below the first thermal plate and immediately above the second thermal plate, thereby being indirectly heated from above by the first heat source via the first thermal plate and indirectly heated from below by the first zone of the second heat source via the second thermal plate. A thermal ring plate which laterally surrounds the edge of the wafer absorbs heat energy emitted from the second zone of the second heat source and heats the outer edge of the wafer.