Abstract: An electrostatic chuck is made by a method in which the component parts are machined, then anodized to provide a hard insulating surface, and then assembled in a fixture, to provide a planar surface for wafer support that retains superior insulating properties; gas may be fed from the rim only, diffusing within interstices between the clamping surface and the wafer and maintaining a desired pressure by flowing radially through an impedance determined by the average spacing between clamping surface and wafer, thereby providing uniform pressure across the clamping surface without the use of elastomeric seals.

Abstract: A method and apparatus for reducing particulates in a plasma tool using steady state flows includes a device, operatively coupled to a housing in which an object to be processed is positioned, for generating a plasma flow adjacent the object toward a pumping aperture. A pumping mechanism pumps a medium adjacent the object. The medium supports the plasma and entrains particulates in the plasma away from the object and out the pumping aperture. Magnetic fields, produced by multipole magnets forming a ring cusp, are preferably used to produce the plasma flow which is directed radially away from the object to be processed. In a second embodiment, an array of magnets which form a line cusp is provided to produce an opening through which plasma will flow.

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: An electrostatic chuck has its electrodes biased with respect to the self-bias potential induced by the plasma on the wafer, thereby providing improved resistance to breakdown in spite of variation of the wafer potential during processing, further suppressing the formation of vacuum arcs between the back of the wafer being processed and the body of the chuck by the interposition of a conductive guard ring at the self-bias potential, thereby defining an equipotential area between the closest electrode and the wafer.

Abstract: An electrostatic chuck suppresses the formation of vacuum arcs between the back of the wafer being processed and the body of the chuck by the interposition of a guard ring that floats close to the self-bias potential induced by the plasma on the wafer, thereby capacitively dividing the voltage between the wafer and the closest electrode.

Abstract: An electrostatic chuck and method of manufacture of the chuck in which the component parts are machined, then partially anodized to provide a hard insulating surface on surfaces that are not in contact with the wafer, and then assembled, after which the top surface abutting the workpiece is machined and a correction radius is cut to suppress discharges between the electrodes.

Abstract: Apparatus and methods for plasma processing involving the gettering of particles having a high charge to mass ratio away from a semiconductor wafer are disclosed. In one aspect of the invention, magnets are used to produce a magnetic field which is transverse to an electric field to draw the negative particles away from the wafer to prevent the formation of a sheath which can trap the particles. In a second aspect of the invention, a power source is connected to the wafer electrode to maintain a negative charge on the wafer, thereby preventing negative particles from being drawn to the wafer surface when the plasma is turned off. In other embodiments of the invention, a low density plasma source is used to produce a large plasma sheath which permits particles to cross a chamber to be gettered. A low density plasma discharge followed by a pulse to a higher density is used to overcome the negative effect of an insulating layer between the wafer and the wafer electrode.

Abstract: A canopy assembly for use at fast food restaurants or the like and beneath which vehicles normally drive. An over-height impact bar is carried by a frame of the canopy assembly and when struck, first energizes an alarm and then travels over a first lost motion distance enabling a driver to react to the alarm and stop the vehicle before it strikes the canopy. Should the driver not stop, the impact bar travels a second lost motion distance to cause a latch to be unlatched and permit the assembly to be swung by the oncoming vehicle clear of its path of movement.

Abstract: A hydraulic flow control valve assembly comprises an inlet port for input fluid flow from a pump, a first outlet port for output fluid flow to a power steering unit, a second-outlet port for output fluid flow to an accumulator of a braking system, and an excess flow port for output fluid flow to other services or a tank. A flow control valve controls the fluid flow from the inlet port to the outlet ports and the excess flow port, and a load sensing port communicates a load-dependent pressure signal from the power steering unit to the valve so as to provide priority fluid flow to the power steering unit. A pilot valve is provided for cutting off the load-dependent pressure signal when the pressure within the accumulator falls below a predetermined value so as to provide for fluid flow from the valve to the accumulator, and in addition a pressure difference sensing arrangement communicates the pressure difference across a restrictor to the valve so as to provide fluid flow to the accumulator.

Abstract: Apparatus for plasma processing involving the gettering of particles having a high charge to mass ratio away from a semiconductor wafer are disclosed. In one aspect of the invention, magnets are used to produce a magnetic field which is transverse to an electric field to draw the negative particles away from the wafer to prevent the formation of a sheath which can trap the particles. In a second aspect of the invention, a power source is connected to the wafer electrode to maintain a negative charge on the wafer, thereby preventing negative particles from being drawn to the wafer surface when the plasma is turned off. In other embodiments of the invention, a low density plasma source is used to produce a large plasma sheath which permits particles to cross a chamber to be gettered. A low density plasma discharge followed by a pulse to a higher density is used to overcome the negative effect of an insulating layer between the wafer and the wafer electrode.

Abstract: A CHF.sub.3 -based RIE etching process is disclosed using a nitrogen additive to provide high selectivity of SiO.sub.2 or PSG to Al.sub.2 O.sub.3, low chamfering of a photoresist mask, and low RIE lag. The process uses a pressure in the range of about 200-1,000 mTorr, and an appropriate RF bias power, selected based on the size of the substrate being etched. The substrate mounting pedestal is preferably maintained at a temperature of about 0.degree. C. Nitrogen can be provided from a nitrogen-containing molecule, or as N.sub.2. He gas can be added to the gas mixture to enhance the RIE lag-reducing effect of the nitrogen.

Abstract: An optimized helical resonator which increases the plasma density for efficient processing of semiconductor wafers is characterized by a low inductance and, hence, a low Q. A first embodiment uses either a distributed or lumped capacitance to reduce the value of .omega.L to less than about 200 Ohms. A second embodiment uses a flat spiral coil having a low value of .omega.L and resonant as a 1/4 or 1/2 wave resonator. A third embodiment combines features of the first two embodiments using both spiral and solenoid coils as the helical resonator.

Abstract: An electrostatic chuck for semiconductor wafers comprised of a multilayered ceramic, including a back-side-metal layer pattern adjacent the upper wafer receiving surface for generating an electrostatic force. Intermediate via layers connect the pattern to a back-side-metal layer at the bottom of the chuck to which power leads can be connected. A number of small passages, extending from the bottom of the chuck to its upper surface, allow helium heat transfer without the need for surface grooves.

Abstract: A cylindrical plasma reaction chamber is equipped with a pair of axially separated solenoid coils and a multipole magnet structure extending between the coil pair. An axially-directed magnetic field and a transverse cusp field are respectively provided by the coils and the magnet. A working gas is contained within the chamber and is excited by applied microwave energy. The strengths of the two magnetic fields and the microwave frequency value are selected to produce a substantially closed electron cyclotron resonance (ECR) zone of proper size. This ECR zone is located axially between the solenoid fields. Baffling is used to separate the closed plasma ECR zone from the workpiece region of the chamber. A semiconductor wafer is positioned within the workpiece region to intercept most plasma particles which follow the axially directed magnetic lines passing through the ECR zone. Few of the particles from the closed ECR zone travel to destinations other than the wafer.

Abstract: A sputter deposition system includes a hollow, cylindrical sputter target 14 disposed between an end sputter target 12 and a substrate 19, all of which are contained in a vacuum chamber 20. A plurality of magnets 24 are disposed outside the chamber 24 to create intense, plasma regions 48 near the interior surface of the cylindrical target 14 and thereby causing ionization of sputtered neutrals. Rf power is inductively coupled into the chamber 24 through rf coil 16 to sustain the plasma and substrate 19 is electrically biased to control ion directionality and energy.