摘要:
In a two-step etching process for making tapered contact openings in a dieletric, a thin layer of a material is interposed to serve as an adhesive between the dielectric and a photoresist layer the thin layer of material is chosen to remain essentially intact during undercut partial etching of the dielectric. As a result of enhanced adhesion, the photoresist layer remains more accurately positioned for subsequent anisotropic etching across the remainder of the thickness of the dielectric.
摘要:
A magnetic field enhanced plasma etch reactor system and method of operation is disclosed. In the system and operation, modulated sinusoidal currents are generated and applied 90.degree. out of phase to opposing pairs of series connected electromagnets to produce a modified rotating magnetic field parallel to a substrate processed in the system. The modification of the rotating magnetic field, in turn, results in an improvement in the uniformity of the etch pattern over the upper surface of the substrate.
摘要:
The invention improves etch uniformity across a silicon wafer surface in an RF plasma etch reactor. In a first aspect of the invention, etch uniformity is enhanced by reducing the etchant species (e.g., Chlorine) ion and radical densities near the wafer edge periphery without a concomitant reduction over the wafer center, by diluting the etchant (Chlorine) with a diluent gas which practically does not etch Silicon (e.g., Hydrogen Bromide) near the wafer edge periphery. In a second aspect of the invention, etch rate uniformity is enhanced by more rapidly disassociating Chlorine molecules over the center of the wafer to increase the local etch rate, without a concomitant hastening of Chlorine dissociation near the wafer periphery, by the introduction of an inert gas over the wafer center. In a third aspect of the invention, etch rate uniformity is enhanced by forcing gas flow from the gas distribution plate downward toward the wafer center to provide a greater concentration of Chlorine ions over the wafer center, by reducing the effective diameter of the chamber between the gas distribution plate and the wafer to approximately the diameter of the wafer. In a fourth aspect of the invention, etch rate uniformity is enhanced by reducing RF power near the wafer edge periphery, by reducing the RF pedestal to a diameter substantially less than that of the wafer.
摘要:
In one aspect, the invention is embodied in a plasma reactor for processing a semiconductor wafer, the reactor having a pedestal focus ring surrounding the periphery of the wafer for reducing the process etch rate near the wafer periphery, and plural openings through the pedestal focus ring which permit passage therethrough of particulate contamination, thereby reducing accumulation of particulate contamination near the wafer periphery. In another aspect, in order to reduce corrosive wear of the chamber walls, a removable gas distribution focus ring shields the side walls of the plasma reactor from reactive gases associated with processing of the semiconductor wafer.
摘要:
In a method of fabricating semiconductor integrated circuits, the effects of mobile ion contamination in a dielectric layer which has been subjected to a source of mobile ion contamination, e.g., reactive ion etching, is substantially eliminated by removing substantially only the topmost portion of the dielectric layer, e.g., 10-15 nm of an 800 nm layer, promptly after performing the step which produced the source of contamination.
摘要:
A plasma etch process is described for simultaneously removing photoresist and etch residues, such as silicon oxide residues, remaining on a substrate from a prior polysilicon and/or polycide etch. The process comprises: (a) generating radicals in a plasma generator upstream of an etch chamber, from an etch gas mixture comprising (i) oxygen, water vapor, or a mixture of same; and (ii) one or more fluorine-containing etchant gases; and (b) then contacting the substrate containing the photoresist and residues from the previous polysilicon/polycide etch with the generated radicals in the etch chamber to remove both the photoresist and the etch residues during the same etch step.
摘要:
The addition of a gaseous source of hydrogen radicals, such as hydrogen, ammonia or methane to oxide RIE etching chemistries, in amounts of from about 5 to about 20 percent by volume of the total gas flow, will increase the oxide etch rate while suppressing the polysilicon etch rate. This effect is more pronounced at lower wafer temperatures. This new process chemistry increases the oxide etch rate to greater than 5000 .ANG./min., improves the selectivity to polysilicon to greater than 25:1 and improves the selectivity to photoresist to greater than 6:1, without having a significant detrimental effect on the profile angle, the RIE lag and the etch rate uniformity. Selectivities of 50:1 have been achieved with less than 15% RIE lag using the chemistry CHF.sub.3, Ar, CF.sub.4 and NH.sub.3, with NH.sub.3 constituting 10 percent by volume of the gas flow.
摘要:
The invention improves etch uniformity across a silcon wafer surface in an RF plasma etch reactor. In a first aspect of the invention, etch uniformity is enhanced by reducing the etchant species (e.g., Chlorine) ion and radical densities near the wafer edge periphery without a concomitant reduction over the wafer center, by diluting the etchant (Chlorine) with a diluent gas which practically does not etch Silicon (e.g., Hydrogen Bromide) near the wafer edge periphery. In a second aspect of the invention, etch rate uniformity is enhanced by more rapidly disassociating Chlorine molecules over the center of the wafer to increase the local etch rate, without a concomitant hastening of Chlorine dissociation near the wafer periphery, by the introduction of an inert gas over the wafer center. In a third aspect of the invention, etch rate uniformity is enhanced by forcing gas flow from the gas distribution plate downward toward the wafer center to provide a greater concentration of Chlorine ions over the wafer center, by reducing the effective diameter of the chamber between the gas distribution plate and the wafer to approximately the diameter of the wafer. In a fourth aspect of the invention, etch rate uniformity is enhanced by reducing RF power near the wafer edge periphery, by reducing the RF pedestal to a diameter substantially less than that of the wafer.
摘要:
Particles are repelled from the upper face of a wafer in a plasma chamber by inducing positive or negative charges on the substrate without generating a gas plasma above the substrate. The charges are induced in the substrate by bringing a conductive sheet carrying a DC voltage close to the underside of the substrate. The particle repelling effect may be enhanced by inducing alternating positive and negative charges in the substrate. This can be done by switching the polarity of the DC voltage applied to the conductive sheet, or alternatively by moving an actuator to repetitively ground and isolate the substrate from the chamber.
摘要:
An integrated circuit is made by a technique that provides a planar dielectric over gate, source, and drain regions without over-etching of the gate contact region, In the inventive process, the contact windows are etched in the conformal dielectric prior to the planarization step, so that the etch thickness is the same for the gate as for the source/drain windows. Then, a sacrificial planarizing polymer (e.g., a photoresist) is deposited to cover the conformal dielectric and fill the etched windows. Finally, a planarizing etch-back is performed, and the polymer is removed from the contact windows. A planarized dielectric is achieved without excessive etching of the gate windows.