Polishing pad, process for producing the same and method of polishing therewith

Abstract

Provided is a polishing pad comprising a fiber including organic fiber and a matrix resin holding the fiber, wherein at least the organic fiber is exposed on the work material-side surface thereof at least after dressing. The polishing pad suppresses generation of minute polishing scratches on the work material and allows flat polishing at low load. It in also possible to manage the polishing end point of the work material without generation of polishing scratch with its optical detection system monitoring the polishing state of work material. Thus, for example, it is possible to polish substrates under a small load on the interlayer insulating film and give products superior in flatness in semiconductor device manufacturing processes and thus, the polishing pad according to the invention may be used easily in the next-generation dual damascene method.

Description

TECHNICAL FIELD [0001] The present invention relates to a polishing pad for use in chemical mechanical polishing (CMP), for example, in semiconductor device-manufacturing technologies and for precision polishing in hard disk-manufacturing technologies, a production method thereof, and a polishing method using the polishing pad. BACKGROUND ART [0002] In the current trend toward increase in packaging density of ultralarge-scale integrated circuits, various microfabrication technologies are now under research and development. The design rule is already in the sub-half micron order. One of the technologies under development for satisfying the strict requirements in microfabrication is CMP (chemical mechanical polishing) technology. The technology is effective in completely flattening the layer to be exposed to light, alleviating the load of exposure technology, and stabilizing the production yield at a high level in the processes for manufacturing semiconductor devices, and the polishin...

AI Technical Summary

Benefits of technology

[0080] The polishing pad is produced in a similar manner to the production method described above, and specifically, each molding in cut into a polishing pad in the predetermined shape (e.g., circular shape) corresponding to the polishing table shape of polishing machine, or the molding is processed into a small piece and inserted as an optically transparent window into a hole in other polishing pad lower in light transmission, to give a polishing pad allowing optical detection. In the latter case, it is preferable to prepare a polishing pad lower in light transmission having a hole for insertion of the window also with a resin plate or the like containing an organic fiber, to enhance the advantageous effects of the present invention, but the fiber content is not particularly limited. The window inserted should be in contact with the work material on the pad surface during polishing. It is because, if the window and the work material are significantly separated from each other, the polishing slurry may flow into the space and inhibit optical detection by scattering the transmitted light. The shape of the window is not particularly limited, but the size thereof should be large enough to ensure an optical path allowing proper operation of the photoirradiator / detector sensor system placed in the polishing machine for optical detection, and the window preferably has an area of approximately 0.1 to 10% with respect to the entire of the polishing pad surface.

[0081] Hereinafter, the polishing method by using the polishing pad according to the present invention will be described. The polishing method according to the present invention is a method for polishing a work material's polishing plane by pressing the polishing plane of the work material to the organic fiber-exposed face of any one of the polishing pads according to the present invention described above and sliding the pad and the work material relatively while supplying a polishing slurry between the work material's polishing plane and the polishing pad.

[0082] Examples of the work materials include the substrate carrying a silicon oxide film formed, for example, by the TEOS-plasma CVD method after a device pattern is formed thereon with a silicon nitride film and the Si exposed area is etched in the shallow trench isolation step, and the substrate having an interlayer insulating film having viaholes and wiring trenches formed by dry etching a barrier conductive film that cover the openings and the internal wall completely formed thereon and additionally a Cu film formed thereon in the state without any opening in the damascene method.

[0083] The CMP polishing slurry for use in the polishing method according to the present invention is not specified here, but an example thereof for insulation films is a polishing slurry prepared by dispersing a composition consisting of cerium oxide (ceria) or silicon oxide (silica) particles and a dispersant in a dispersion medium such as water and adding additives additionally. The polishing slurry for metal layers such as of Cu is, for example, a polishing slurry prepared by dispersing abrasive ouch as silica, alumina, ceria, titania, zirconia, or germania, additives, and an anticorrosive in water and adding peroxides additionally. Colloidal silica or alumina particles are particularly favorable as the abrasive. The content of the abrasive particles is preferably 0.1 to 20 wt %. The abrasive particles may be prepared in any way, but the average diameter is preferably 0.01 to 1.0 μm. The abrasive particles having an average diameter of less than 0.01 μm leads to decrease in polishing speed, while that of more than 1.0 μm causes an increased number of scratches.

[0084] The polishing machine is not particularly limited, and, for example, a disk polishing machine or a linear polishing machine may be used. For example, common polishing machines having a holder for holding a work material and a polishing table for attaching a polishing pad that is connected to a variable frequency motor may be used. An example is a polishing machine EP0111, manufactured by Ebara Corporation.

[0085] In particular in the polishing method by using a polishing pad of the third embodiment allowing optical detection of polishing end point, the polishing end point is managed by irradiating a light at a wavelength of 190 to 3,500 nm via the polishing pad onto the polishing plane of the work material and detecting the change in reflectance while polishing the work material's polishing plane by sliding the polishing pad relatively to the work material as described above.

Problems solved by technology

There is a problem of damage (polishing scratch) on the polishing plane by abrasive and polishing waste.

However, the decrease in rigidity often results in decrease in polishing speed and deterioration of the dishing of trench area.

It was difficult to satisfy these properties at the same time.

In particular, the metal, which is more chemically reactive and softer than the interlayer insulating film, often causes defects by polishing scratch and corrosion.

However, increase in the elastic modulus of pad generally leads to increase in pad rigidity and consequently to defects such as polishing scratch.

In addition, recent application of a low-dielectric constant material to the interlayer insulating film is accompanied by deterioration in the mechanical properties of insulation layer and the adhesion with metal and is a factor causing defects during polishing, and thus, there is a need for a polishing system having lower mechanical load demands during polishing.

However, these polishing pads have problems demanding-reduction of polishing scratch during CMP polishing and preservation of polishing speed while optical detection of end point, and in particular in the damascene, as described above it is important to reduce generation of the defects caused by polishing scratch and corrosion.