Browse Prior Art Database

Polishing Pad Wear Detection

IP.com Disclosure Number: IPCOM000131998D
Publication Date: 2005-Nov-28
Document File: 2 page(s) / 12K

Publishing Venue

The IP.com Prior Art Database

Abstract

Polishing equipment is becoming more sophisticated due to the rising demands of such applications as silicon wafer polishing for integrated circuits and other applications. A common variety of polishing equipment consists of a polishing head holding the item to be polished, a polishing media, and a platen on which the polishing media is mounted. Some of these machines use a multilayer polishing media with one or more sub pads below the top polishing media. Some of them also utilize a polishing slurry applied to the polishing media for enhanced removal of the target material. Many of the polishing machines now incorporate various forms of on-line analysis of the material being polished or the polishing media. Often this inspection employs electromagnetic radiation including simple visual analysis. A signal is aimed at, along, or through the polishing media, sometimes through a window or opening in the media. The return or reflected signal is analyzed to determine characteristics such as the end point of the polishing, the end-of-life of the polishing media, and the presence of the polishing media on the platen. Since this process is carried out while the material is being polished, any improvements that can enhance the discrimination of the signal would be welcomed. For applications where a window or opening is used, it is important for the edges of the signal to be clearly defined to avoid edge noise. For applications where a reflected signal is used, an increased contrast between the polishing media and the platen is also helpful. In both cases, modification of the polishing media is often difficult due to the other demands placed upon the media. One possible solution is to modify the typical adhesive constructions used to bond the polishing media to the platen or sub pad. Pigmenting the adhesive, however, may alter the adhesion levels or introduce an undesirable, extractable material when in the polishing environment. An alternative is to modify the film carrier layer of a double-coated tape. Typically, a double coated tape having an adhesive layer on each side of a film carrier is used to attach the polishing media to the platen. For applications that require a lighter appearance, the standard clear polyester (typically 5% haze) can be changed to a higher haze polyester (typically 17% or more). The higher haze may appear white or lighter colored with specific adhesives. Alternatively, a lightly colored polyester, achieved through the incorporation of pigments or dyes in the polyester may be employed to achieve a similar effect. For applications that require a darker appearance, the replacement could be the higher haze polyester or a darker colored polyester depending upon which works best in combination with the specific adhesive. In either case, changing the appearance by altering the polyester may enhance the capability of the measurement systems in the polishing tools without affecting either the polishing process or the adhesive bonds.

This text was extracted from a Microsoft Word document.
This is the abbreviated version, containing approximately 52% of the total text.

Polishing Pad Wear Detection 

            Polishing equipment is becoming more sophisticated due to the rising demands of such applications as silicon wafer polishing for integrated circuits and other applications.  A common variety of polishing equipment consists of a polishing head holding the item to be polished, a polishing media, and a platen on which the polishing media is mounted.  Some of these machines use a multilayer polishing media with one or more sub pads below the top polishing media.  Some of them also utilize a polishing slurry applied to the polishing media for enhanced removal of the target material. 

Many of the polishing machines now incorporate various forms of on-line analysis of the material being polished or the polishing media.  Often this inspection employs electromagnetic radiation including simple visual analysis.  A signal is aimed at, along, or through the polishing media, sometimes through a window or opening in the media.  The return or reflected signal is analyzed to determine characteristics such as the end point of the polishing, the end-of-life of the polishing media, and the presence of the polishing media on the platen.

            Since this process is carried out while the material is being polished, any improvements that can enhance the discrimination of the signal would be welcomed.  For applications where a window or opening is used, it is important for the edges of the signal to be clearly defined to avoid edge noise.  For applications where a reflected signal is used, an increased contrast between the pol...