Abstract: Plastic cassettes carrying semiconductor wafers are loaded into and/or unloaded from an extended open drawer. The drawer is retractable to a closed position in a frame where the cassettes may be removed from or returned to the drawer by a programmable elevator. The frame may have several drawers and cassettes may be safely loaded into or unloaded from the open drawer while cassettes are being removed from or returned to a closed drawer.

Abstract: A diffusion furnace and method for processing semiconductor wafers standing on edge wherein the furnace has vertically adjacent electrical resistance heating elements wired in parallel and disposed above the wafers. This arrangement enables the heat input to the furnace by the heating elements to be varied. In a preferred embodiment, the heating elements in the upper section of the tube are connected in one circuit and the heating elements in the lower section of the tube are connected in a second circuit and each circuit is controlled in response to the temperature in that section.

Abstract: A wafer boat transfer tool has an upper fork and a lower fork which may be differently configured for supporting wafer boats in different ways. The same tool may be used to transfer boats in one or more steps from locations where they are supported in one way to other locations where they are supported in the same or a different way. Also, the tool may be used to transfer more than one boat at a time without excessive travel in a direction parallel to the boat loader axis.A versatile wafer designed for use with two different forks of the tool may be utilized with different boat loaders and a common wafer transfer machine and in-process storage nests.

Abstract: A process and apparatus for the low pressure, cold wall, chemical vapor deposition of refractory metals, such as tungsten on a silicon wafer. The silicon wafer is introduced into a loading lock wherein the pressure is reduced to subatmospheric pressure. The silicon wafer is transferred to a deposition chamber where it is heated to an elevated temperature. A refractory metal carbonyl vapor is introduced into the deposition chamber and dissociates to deposit a refractory metal on the silicon wafer. The wafer is transferred to an unloading lock where it is allowed to cool and is then removed.

Abstract: Semiconductor wafers in plastic cassettes are loaded into (and later unloaded from) an input/output station serving a CVD furnace and thereafter the cassettes are non-manually transported by a programmable elevator to and from a flat-finder, a wafer transfer machine (where the wafers are transferred to a boat) and in-process storage. The boats are non-manually transported by a second programmable elevator to and from the wafer transfer machine, in-process boat storage and a boat loader (or process chamber directly). The cassettes can be loaded or unloaded while one or both of the elevators are operating. Up to eight human assisted steps are reduced to only two such steps.

Abstract: Empty wafer cassettes are stored on a transfer stand having one or more storage locations on a post which extends below a wafer comb while the wafers are being processed. Each storage location generally has a cross bar with spaced upward projections for receiving the leg of a cassette.

Abstract: A soft landing cantilever boat loader for loading semiconductor wafer carrying boats into a furnace process tube includes a loading station having one or more loading assemblies, an automatically controlled door associated with each loading assembly for selectively closing an end of the process tube and a microcomputer based control system for controlling and coordinating process operations. The loading assemblies are of a low profile configuration and each include a boat supporting, cantilevered paddle that is mounted by a quick release mechanism on a carriage which is driven along ways by a motor. A motor speed control circuit provides closed loop motor speed using a pulse width modulated motor drive. A door operating mechanism provides movement of the door along two transverse axes to assure tight sealing of the door against the tube.

Abstract: A gas scavenger unit educts gases away from semiconductor wafers as they are withdrawn through a plenum in the scavenger from their processing chamber into the atmosphere. The scavenger has a peripheral wall which generally defines a plenum having two open ends. The one end of the plenum communicates with the processing chamber and the other end communicates with the atmosphere. An exhaust port in the peripheral wall communicates with a house gas exhaust system. The plenum is divided into two chambers by an apertured interior wall. The wafers travel through the first chamber, and the second chamber communicates with the house gas exhaust system. The apertures in the interior wall are disposed about the wafer travel path so that gases from the processing chamber and/or the atmosphere are educted into the house exhaust system without flowing across the wafers.

Abstract: There is a substantial heat loss and drop in temperature in a hot-wall diffusion tube when a batch of wafers at room temperature is loaded into the tube. The temperature of the atmosphere in a zone in the tube is quickly recovered by sensing both the temperature of the tube atmosphere and the temperature of a heating element surrounding the zone with thermocouples, mixing the signals of the thermocouples to produce a ratio average signal and then controlling the heat input to the heating elements in response to the ratio average of the sensed temperature.

Abstract: A soft landing cantilever boat loader for loading semiconductor wafer carrying boats into a furnace process tube includes a loading station having one or more loading assemblies, an automatically controlled door associated with each loading assembly for selectively closing an end of the process tube and a microcomputer based control system for controlling and coordinating process operations. The loading assemblies are of a low profile configuration and each include a boat supporting, cantilevered paddle that is mounted by a quick release mechanism on a carriage which is driven along ways by a motor. A motor speed control circuit provides closed loop motor speed using a pulse width modulated motor drive. A door operating mechanism provides movement of the door along two transverse axes to assure tight sealing of the door against the tube.

Abstract: A soft landing cantilever boat loader for loading semiconductor wafer carrying boats into a furnace process tube includes a loading station having one or more loading assemblies, an automatically controlled door associated with each loading assembly for selectively closing an end of the process tube and a microcomputer based control system for controlling and coordinating process operations. The loading assemblies are of a low profile configuration and each include a boat supporting, cantilevered paddle that is mounted by a quick release mechanism on a carriage which is driven along ways by a motor. A motor speed control circuit provides closed loop motor speed using a pulse width modulated motor drive. A door operating mechanism provides movement of the door along two transverse axes to assure tight sealing of the door against the tube.

Abstract: A soft landing cantilever boat loader for loading semiconductor wafer carrying boats into a furnace process tube includes a loading station having one or more loading assemblies, an automatically controlled door associated with each loading assembly for selectively closing an end of the process tube and a microcomputer based control system for controlling and coordinating process operations. The loading assemblies are of a low profile configuration and each include a boat supporting, cantilevered paddle that is mounted by a quick release mechanism on a carriage which is driven along ways by a motor. A motor speed control circuit provides closed loop motor speed using a pulse width modulated motor drive. A door operating mechanism provides movement of the door along two transverse axes to assure tight sealing of the door against the tube.

Abstract: A process and apparatus for the low pressure, cold wall, chemical vapor deposition of refractory metals, such as tungsten on a silicon wafer. The silicon wafer is introduced into a loading lock wherein the pressure is reduced to subatmospheric pressure. The silicon wafer is transferred to a deposition chamber where it is heated to an elevated temperature. A refractory metal carbonyl vapor is introduced into the deposition chamber and dissociates to deposit a refractory metal on the silicon wafer. The wafer is transferred to an unloading lock where it is allowed to cool and is then removed.

Abstract: A process for chemical vapor deposition of borophosphosilicate glass on a silicon wafer at reduced pressure is disclosed herein. The process includes a step of placing a silicon wafer within a reactor tube. The reactor tube is evacuated to a pressure of less than 500 millitorr and is heated to a temperature of not less than 350.degree. C. and not greater than 500.degree. C. A mixture of silane, phosphine and boron trichloride gases is flowed into the reactor tube so that the mixture contacts the silicon wafer. At the same time, a quantity of oxygen is flowed into the reactor tube so that the oxygen also contacts the silicon wafer and intermixes and reacts with the silane, phosphine and boron trichloride gases to form layers of borophosphosilicate glass on the silicon wafer.