Polishing pad process for producing the same and method of polishing

Abstract

According to the present invention, there is provided a polishing pad for polishing the surface of wafers for creating semiconductor integrated circuits, wherein said pad has a high polishing speed, said polishing is uniform, and said pad has a long life. Preferably, the polishing pad of the present invention comprises nonwoven fabric (base matrix) and a nonporous photo-setting resin that fills the space between the nonwoven fabric, and can be produced by impregnating the base matrix with a photo-sensitive resin composition containing at least one selected from the group consisting of a hydrophilic photopolymeric polymer or oligomer, and / or a hydrophilic photopolymeric monomer, and then photo-setting the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a polishing pad for use in the step of planarizing non planar steps on the surface of wafers for creating semiconductor integrated circuits by the chemical mechanical polishing process, a method of producing the pad, and method of polishing using the pad. BACKGROUND ART [0002] Processes for manufacturing semiconductor integrated circuits include the process of creating a conductive film on the surface of wafers and then forming a wiring pattern by photolithography and etching, and the process of forming an interlevel dielectric film on said wiring pattern. Through these processes, there is formed non planar steps consisting of conducting materials and insulating materials on the surface of wafers. In recent years, as miniturization and multi-layering of wiring pattern are in progress for the purpose of attaining higher density of semiconductor integrated circuits, techniques for planarizing non planar steps on the surface of wa...

AI Technical Summary

Benefits of technology

[0018] According to the present invention, there is provided a polishing pad having a higher polishing speed than the conventional polishing pads, higher uniformity in polishing, and that has an extended life (i.e., a polishing pad is provided that simultaneously satisfies the above three requirements). Specifically, there is provided a polishing pad having a high planarizing ability that is suitable for polishing of thick conductor patterns such as the copper wiring pattern or the aluminum wiring pattern of the above-mentioned damascene wiring. According to the present invention, there is provided a method of polishing a wiring pattern comprising copper or aluminum formed on the surface of wafers for creating semiconductor integrated circuits using the above polishing pad. According to the present invention, furthermore, there is provided a method of manufacturing the above polishing pad for use in polishing the surface of wafers for creating semiconductor integrated circuits.

Problems solved by technology

However, since it is difficult to secure uniformity in reaction temperature and uniformity in foaming factor throughout the entire reaction vessel in the production of said polishing pads, it is difficult to produce products that are uniform throughout the polishing pads.

Also since slurry components or products generated during polishing tend to precipitate in the above hemispheric recesses in said pads, they have a drawback of clogging by precipitates in a relatively short period of time.

Thus, they have-problems that long dressing time in a total during polishing is required and that the polishing pad has a short life.

Thus, the polishing pads comprising such polyurethane foams have not always satisfied the above three requirements for the polishing pad (thus, a high polishing speed, abrasion resistance, planarizing ability).

However, the process of producing said polishing pad mainly comprises a drying step and a heat reaction step, and the reaction mixture is at a state in which it tends to aggregate, and thus it is difficult to maintain the composition and physical properties of the polishing pad materials uniformly on microscopic levels.

Furthermore, since it has compressibility derived from the open cell structure, it has a problem of poor planarizing ability.

Furthermore, due to the presence of space between single fibers in felt sheet as continuous air bubbles, polishing crumbles generated in wafer polishing become tangled with said fiber and thus scratches may often appear in the polished product.

Therefore, in the polishing pads in which polyurethane has been impregnated into a polyester felt fiber sheet, satisfactory results have not been obtained in terms of the polishing speed and the planarizing ability.

However, the above polishing pads using a resin having a nonporous structure only have concave-convex on the surface thereof by conditioning treatment etc., and thus they have a problem that they do not have sufficient ability to retain the slurry and have low polishing speeds.

Besides, they have a problem that the life of the polishing pads is short.

However, even if a filler is added to the resin, each filler is independently dispersed in the polishing pad and removed from the polishing surface by polishing, and thus it has little effect of enhancing abrasion resistance of the polishing surface and the extended life of the polishing pad cannot be expected.

Thus, although drawbacks resulting from the production process of a polishing pad using a resin having a closed or open cell structure can be eliminated by the polishing pad using a resin having a nonporous structure, the above three requirements for the polishing pads could not be satisfied at the same time.

Thus, with the polishing pad using a resin having a nonporous structure, uniformity as a whole can be obtained which contributes to the planarizing ability, it was not satisfactory in terms of high polishing speed (ability of transporting and retaining the slurry) or abrasion resistance.

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