Abstract: At atmosphere X and an atmosphere Y, which may be an oxidizing atmosphere, are used in a process wherein silicon wafers are processed in a processing chamber, which is pressurized sequentially with a purging atmosphere, with the atmosphere X, and with the atmosphere Y displacing the atmosphere X excpet for a residual portion remaining with the atmosphere X and diminishing in concentration with time. As the atmosphere X has a molecular weight approximating the molecular weight of the atmosphere Y, stratification is minimized. If the atmosphere Y is steam, the atmosphere X may be a premixture of helium and oxyen.

Abstract: A gas flow control system in which several constituent gases are mixed and the mixture delivered through controlled injectors to a processing zone. Mass flow controllers control the injector flows with one of the controllers being a master and the other being slaved to provide a selected percentage of the flow through the master controller. The gas mix is regulated by a mass flow controller on one of the constituents and a flow meter on the other, the flow meter producing an error signal which is used to readjust the total flow through the injectors by control of the master injector flow controller.

Abstract: Apparatus for thermal oxidation of silicon wafers at high pressures of a type wherein a reactor of a refractory material is disposed within a pressure vessel, and wherein a margin of a wafer portal of the reactor and a closure of the refractory material have congruent surfaces enabling a hermetic seal to be effected, an improvement is disclosed wherein the closure is mounted within a pressure-vessel head used to close an access portal of the pressure vessel by means of gimbals, whereby a hermetic seal can be effected at said surfaces despite misalignments.

Abstract: For a vacuum pump, as used to maintain a partial vacuum in a diffusion furnace for chemical vapor deposition in intermittent runs wherein oil for the vacuum pump becomes contaminated by particulates, an apparatus for removal of particulates from oil for the vacuum pump comprises a settling tank, which is connected to receive oil from the vacuum pump, an oil pump, which is arranged to pump oil from the settling tank, means for filtering particulates from oil pumped from the settling tank, a plurality of oil valves, which are arranged to control flow of oil from the vacuum pump, through the settling tank, through the filtering means, and into the vacuum pump, means for operating the oil pump and opening the oil valves for timed intervals wherein oil flows from the vacuum pump, through the settling tank, through the filtering means, and to the vacuum pump, and means for coordinating the intervals with the runs so that each interval is initiated approximately when a run is terminated.

Abstract: A gas flow control valve having the means of adjusting the tension of the spring to the plunger through which the electromagnetic actuating coil moves the plunger from the valve seat in proportion to the required flow by an externally accessible adjustment means.