Abstract: VHF/UHF power having a frequency of about 40 MHz or higher is applied across generally radial elements of an antenna and the phase of a standing wave component of the voltage in the generally radial elements is adjusted to provide relatively uniform density of a high density plasma across an area of at least the size of a semiconductor wafer being processed. Capacitive coupling of power to the plasma enhances the hot tail distribution of electron energies which is associated with low levels of gas cracking and the production of radicals such as fluorine which are not material-selective in semiconductor processing operations such as oxide etching. Accordingly, material-selectivity of processes may be maintained while the high density plasma accelerates the process to significantly improve tool throughput.

Abstract: An apparatus and method of producing a negative ion plasma for use in manufacturing of microelectronic devices, particularly etching of microelectronic patterns in semiconductor wafers. A negative ion plasma is produced from a hot electron plasma formed by a RF or UHF plasma source. The negative ion plasma includes positive ions, negative ions and relatively cold electrons, such electrons having an effective electron temperature or average energies less than that for maintaining the plasma. The fields producing the hot plasma are isolated from the negative ion plasma in a cold plasma region by a magnetic filter. The magnetic filter confines the plasmas to provide plasma uniformity at a work piece being etched by the negative ion plasma. The magnetic filter further prevents hot electrons originating in the hot electron plasma from diffusing into the negative ion plasma, while allowing positive ions and cold electrons to diffuse from the hot plasma to the negative ion plasma.

Abstract: An apparatus and method for producing a cold electron plasma for etching a work piece. An electromagnetic wave is generated at a first frequency to produce a plasma in a hot plasma region of the etching chamber, the plasma having positive ions, cold electrons, and hot electrons. A plurality of magnetic coils are disposed about the perimeter of the etching chamber for generating a rotating magnetic field with an electron cyclotron resonance at a second frequency. The rotating magnetic field has a magnetic potential such that the rotating magnetic field: (i) allows the positive ions and the cold electrons to diffuse from the plasma through the rotating magnetic field to produce the cold electron plasma in a cold plasma region over the work piece, and (ii) inhibits the hot electrons from the plasma from diffusing through the rotating magnetic field to the cold electron plasma.

Abstract: Uniformity of plasma density and potential are increased by reducing plasma confinement through use of a non-uniform, graded magnetic field by asymmetric energization of electromagnets with a waveform including harmonics of a fundamental frequency. The magnetic field strength or intensity decreases in the direction of ExB drift of energetic electrons within the plasma which tends to cause additional ionization in the plasma and a gradient of plasma density and potential. Thus, increase in ionization due to ExB drift is balanced by reduction of plasma confinement. Uniformity of average exposure to the plasma is further increased by rotation of the magnetic field. Uniformity of plasma potential or wafer bias is further improved by modulation of the radio frequency (RF) power used to form the plasma in synchronism with decreases in the magnetic field during switching for magnetic field rotation.

Abstract: Apparatus controls a wafer potential in a plasma system when the plasma is off to keep the wafer slightly negative at all times in order to reduce and eliminate the collection of charged particles on the wafer. The apparatus allows the wafer bias to be reduced to a small negative voltage and then holds that voltage. This greatly reduces the net positive flux to the wafer. A diode and a programmed power supply hold a minimum negative voltage on the back of the wafer electrode when the plasma density is decaying to zero.

Abstract: An electrostatic chuck is disclosed that is resistant to the formation of vacuum arcs between the back of the wafer being processed and the body of the chuck. A guard ring surrounds the chuck and floats close to the self-bias potential induced by the plasma on the wafer. The voltage between the wafer and the closest electrode is thereby capacitively divided by the guard ring.

Abstract: Apparatus controls a wafer potential in a plasma system when the plasma is off to keep the wafer slightly negative at all times in order to reduce and eliminate the collection of charged particles on the wafer. The apparatus allows the wafer bias to be reduced to a small negative voltage and then holds that voltage. This greatly reduces the net positive flux to the wafer. A diode and a programmed power supply hold a minimum negative voltage on the back of the wafer electrode when the plasma density is decaying to zero.

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. An alternate embodiment further 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 conductive guard ring at the self-bias potential, thereby defining an equipotential area between the closest electrode and the wafer.

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: 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: 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: 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 dry processing apparatus for plasma etching or deposition includes a chamber for plasma processing having an external wall for housing a work piece with a surface to be plasma processed. A source of an induction field is located outside the chamber on its opposite side from the work piece. A radio frequency induction field applied to the chamber generates a plasma. The plasma is confined within the external wall in the chamber by magnetic dipoles providing a surface magnetic field for confining the plasma. The surface magnetic field is confined to the space adjacent to the external wall. An R.F. generator provides an R.F. generated bias to the work piece. The chamber is lined with a material inert to a plasma or noncontaminating to the work piece, and the induction source in the form of a spiral or involute shaped induction coil is located on the exterior of the liner material on the opposite side of the chamber from the work piece.

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.