Abstract: A process for forming trenches on a surface of a semiconductor substrate by dry etching using a gas mixture. The gas mixture comprises; (1) an etchant gas comprising at least bromine which etches the semiconductor surface to form trenches, (2) a cleaning gas comprising a halogen which evaporates residue formed by the etching, and (3) a reactive gas, e.g. N.sub.2, capable of reacting with material formed during the etching and capable of controlling the inclination of the trenches.

Abstract: Silicon dioxide on a substrate is directionally etched using a hydrogen halide plasma which is created within an etch chamber. The method selectively etches silicon dioxide relative to polysilicon and silicon nitride. A substrate and the combination of NH.sub.3 and NF.sub.3 gases or the combination of CF.sub.4 and O.sub.2 gases mixed with H.sub.2 and N.sub.2 gases are located within an etch chamber. An electrical field is created within the etch chamber causing the gas mixture to form a plasma. The negative charge at the bottom of the chamber attracts the positively charged plasma, thereby etching the substrate in the downward direction. The result is an anisotropic product. The method is also shown to be effective in non-selectively etching thermal and deposited oxides, resulting in a similar etch rate for the different types of oxides.

Abstract: A method for heating or cooling a semiconductor wafer in semiconductor processing apparatus is described which comprises directing into contact with a surface of the wafer at least a portion of one or more components of the process gas to transfer heat between the wafer and a wafer support positioned in the apparatus adjacent to the wafer. Method and apparatus are also described for controlling the total flow of process gas through the apparatus and for monitoring the pressure in said apparatus to maintain the desired pressure therein.

Abstract: A method and apparatus is provided for controlled spray etching, in which panels, such as printed circuit boards are delivered through an etching chamber, to have a spray etchant sprayed generally on upper and lower surfaces of the panel. The spray is controlled such that a reduced amount of etchant is provided on the perimeter surface portions of the panel, relative to the central surface portions of the panel, transversely of the path of travel of the panels through the etching chamber. The spray may be varied in amount, preferably by varying the pressure at different locations transversely of the chamber; the spray longitudinally through the chamber, may vary, to spray leading and trailing surface portions of the panels a lesser amount than central portions of the panels, measured longitudinally. The control of the spray of leading and trailing surface portions of the panels may be facilitated by one or more sensors that control an intermittent discharge of spray etchant near the inlet to the etch chamber.