Abstract:
An inexpensive and safe copper removal method in the fabrication of integrated circuits is described. Copper is stripped or removed by a chemical mixture comprising an ammonium salt, an amine, and water. The rate of copper stripping can be controlled by varying the concentration of the ammonium salt component and the amount of water in the mixture. Also a novel chemical mixture for stripping copper and removing copper contamination is provided. The novel chemical mixture for removing or stripping copper comprises an ammonium salt, an amine, and water. For example, the novel chemical mixture may comprise ammonium fluoride, water, and ethylenediamine in a ratio of 1:1:1.
Abstract:
A method of forming a metal plug, comprising the following steps. An etched dielectric layer, over a conductive layer, over a semiconductor structure are provided. The etched dielectric layer having a via hole and an exposed periphery. The etched dielectric layer is treated with at least one alkaline earth element source to form an in-situ metal barrier layer within the dielectric layer exposed periphery. A metal plug is formed within the via hole wherein the in-situ metal barrier layer prevents diffusion of the metal from the metal plug into the dielectric oxide layer.
Abstract:
A method of bonding a bonding element to a metal bonding pad comprises the following steps. A semiconductor structure having an exposed, recessed metal bonding pad within a layer opening is provided. The layer has an upper surface. A conductive cap having a predetermined thickness is formed over the metal bonding pad. A bonding element is bonded to the conductive cap to form an electrical connection with the metal bonding pad.
Abstract:
A method of removing copper contamination from a semiconductor wafer, comprising the following steps. A semiconductor wafer having copper contamination thereon is provided. An oxidizing radical containing downstream plasma is provided from a first source (alternatively halogen (F2, Cl2, or Br2) may be used as on oxidizing agent). A vaporized chelating agent is provided from a second source. The oxidizing radical containing downstream plasma and vaporized chelating agent are mixed to form an oxidizing radical containing downstream plasma/vaporized chelating agent mixture. The mixture is directed to the copper contamination so that the mixture reacts with the copper contamination to form a volatile product. The volatile product is removed from the proximity of the wafer.
Abstract:
A microelectronic device such as a Metal-Oxide-Semiconductor (MOS) transistor is formed on a semiconductor substrate. A tungsten damascene interconnect for the device is formed using an etch stop layer of silicon nitride, silicon oxynitride or silicon oxime having a high silicon content of approximately 40% to 50% by weight. The etch stop layer has high etch selectivity relative to overlying insulator materials such as silicon dioxide, tetraethylorthosilicate (TEOS) glass and borophosphosilicate glass (BPSG). The etch stop layer also has a high index of refraction and is anti-reflective, thereby improving critical dimension control during photolithographic imaging.
Abstract:
A method for forming dual-damascene type conducting interconnects with non-metallic barriers that protect said interconnects from fluorine out-diffusion from surrounding low-k, fluorinated dielectric materials. One embodiment of the method is particularly suited for forming such interconnects in microelectronics fabrications of the sub 0.15 micron generation.
Abstract:
The present invention relates to the formation of a protective intermetallic layer 15 on the surface of damascene metal interconnects 12 during semiconductor fabrication. The intermetallic layer 15 prevents problems associated with formation of an oxide layer on the surface of the interconnect. The intermetallic layer is formed by depositing a metal on the surface of the interconnect that will both reduce any present metal oxide layer and form an intermetallic with the interconnect metal.
Abstract:
A method of fabricating an interconnection level of conductive lines and connecting vias separated by insulation for integrated circuits and substrate carriers for semiconductor devices using a reverse damascene in the formation of the conductive lines and vias. A conductive line pattern is first used to etch completely through the layer to form conductive line openings. The openings are completely filled with a conductive material and planarized so that the surfaces of the conductive material and the insulating layer are coplanar. A via pattern is aligned perpendicular to the conductive lines and the conductive material is etched half way through the conductive lines in other than the areas covered by the via pattern. The openings thus created in the upper portion of the conductive lines are filled with insulating material to complete the dual damascene interconnection level with the conductive lines in the lower portion of the insulating layer and upwardly projecting vias in the upper portion of the layer. In addition, a triple damascene layer is formed by starting with an insulating layer about one-third thicker than normal and by combining the standard dual damascene method with the above described method. The resulting interconnection level structure comprises conductive lines having upwardly and downwardly projecting vias.
Abstract:
A method and system for providing a via structure for a high conductivity metal of a integrated circuit is disclosed. In a first aspect the method and system comprises etching a photoresist material and a dielectric material down to the high conductivity metal to form a via hole. The via hole includes sputtered high conductivity metal on the sidewalls. The method and system further includes providing a via plug material within the via hole. The vial plug material substantially covers a base portion of the high conductivity metal and the sidewalls of the via hole. The via plug material is also capable of gettering or dissolving the high conductivity metal sputtered on the sidewalls of the dielectric material. In a second aspect, a via structure for an integrated circuit is disclosed in accordance with the present invention. The via structure includes a high conductivity metal and a dielectric material surrounding the high conductivity metal. The dielectric material includes sidewalls to form a via hole on tope of the high conductivity metal. The via structure further includes a via plug material covering the high conductivity metal and substantially filling the via hole. The via plug material is also capable of gettering or dissolving the high conductivity metal sputtered on the sidewalls of the via hole. Accordingly, by providing a via plug material within the via hole, the via plug material getters or dissolves the high conductivity metal that reaches the sidewalls of the dielectric layer during the via etch and sputter etch processes and the junction poisoning problems associated therewith are substantially minimized.
Abstract:
It has been discovered that all causes of critical dimension variation, both known and unknown, are compensated by adjusting the time of photoresist etch. Accordingly, a control method employs a control system using photoresist etch time as a manipulated variable in either a feedforward or a feedback control configuration to control critical dimension variation during semiconductor fabrication. By controlling critical dimensions through the adjustment of photoresist etch time, many advantages are achieved including a reduced lot-to-lot variation, an increased yield, and increased speed of the fabricated circuits. In one embodiment these advantages are achieved for polysilicon gate critical dimension control in microprocessor circuits. Polysilicon gate linewidth variability is reduced using a control method using either feedforward and feedback or feedback alone. In some embodiments, feedback control is implemented for controlling critical dimensions using photoresist etch time as a manipulated variable. In an alternative embodiment, critical dimensions are controlled using RF power as a manipulated variable. A run-to-run control technique is used to drive the critical dimensions of integrated circuits to a set specification. In a run-to-run control technique a wafer test or measurement is made and a process control recipe is adjusted based on the result of the test or measurement on a run-by-run basis. The run-to-run control technique is applied to drive the critical dimensions of a polysilicon gate structure to a target specification. The run-to-run control technique is applied to drive the critical dimensions in an integrated circuit to a defined specification using photoresist etch time as a manipulated variable.