Patent Application
20080200105
1. Field of the Invention
The present invention relates to a carrier film for mounting a polishing workpiece and a method for making the same, and more particularly, to a carrier film for mounting a polishing workpiece and a method for making the same which are used in the chemical mechanical polishing (CMP) process.
2. Description of the Related Art
Polishing generally refers to a wear control for a preliminary coarse surface in the process of chemical mechanical polishing, which makes the slurry containing fine particles evenly dispersed on the upper surface of a polishing pad, and at the same time places a polishing workpiece against the polishing pad and then rubs the polishing workpiece repeatedly with a regular motion. The polishing workpiece may be objects such as a semiconductor, a storage medium substrate, an integrated circuit, an LCD flat-panel glass, an optical glass and a photoelectric panel. During the polishing process, a carrier film must be used for carrying and mounting the polishing workpiece, and the quality of the carrier film directly influences the polishing effect of the polishing workpiece.
The operation mode of the polishing device 1 is as follows. First, the polishing workpiece 13 is mounted on the carrier film 12, and then both the upper and lower base plates 14 and 11 are rotated and the upper base plate 14 is simultaneously moved downward, such that the polishing pad 15 contacts the surface of the polishing workpiece 13, and a polishing operation for the polishing workpiece 13 may be performed by continuously supplementing the slurry 16 and using the effect of the polishing pad 15.
A second type of the conventional carrier film is developed and shown in
The objective of the present invention is to provide a carrier film for mounting a polishing workpiece. The carrier film comprises a surface substrate and a buffer substrate. The surface substrate comprises holes, and the material of the surface substrate comprises elastomer. The buffer substrate comprises holes, and the material of the buffer substrate comprises the elastomer. The surface substrate and the buffer substrate are adhered with adhesive comprising the elastomer. When polishing, the carrier film provides a good buffer property to conduct and release down force applied on the polishing workpiece.
Another objective of the present invention is to provide a method for making the carrier film for mounting a polishing workpiece. The method of the present invention comprises the following steps:
In order to obtain a carrier film for mounting a polishing workpiece that has a satisfactory buffer effect, the invention provides a novel carrier film.
The carrier film comprises a surface substrate and a buffer substrate. The surface substrate comprises holes, and the material of the surface substrate comprises elastomer. The buffer substrate comprises holes, and the material of the buffer substrate comprises the elastomer. The surface substrate and the buffer substrate are adhered with adhesive comprising the elastomer.
The surface substrate according to the invention comprises two surfaces, preferably having a first suede-like surface for mounting the polishing workpiece. The suede-like surface provides more friction and is designed to mount the polishing workpiece more securely. The second surface of the surface substrate preferably comprises a first flat surface for being adhered to the buffer substrate. The first flat surface provides a good interface to be adhered to the buffer substrate with adhesive comprising the elastomer.
In order to provide a better buffer effect, the thickness of the surface substrate is preferably between 0.05 mm to 5.00 mm. The thickness range provides an optimum buffer effect avoiding the existence of a solid bottom as observed in the conventional carrier film.
In one preferred embodiment of the invention, the buffer substrate has a second flat surface. If the second flat surface is located on an upper surface of the buffer substrate, it helps to secure the buffer substrate to the surface substrate through the adhesive comprising the elastomer. On the other hand, if the second flat surface is located on a lower surface of the buffer substrate, it helps to secure the buffer substrate and also the whole carrier film to a lower base plate of a polishing device.
The holes of the surface substrate and buffer substrate are continuous or discontinuous. The holes enable air to be distributed into the substrates and the air cooperates with the elastomer of the substrates to provide a flexible structure for releasing and conducting down forces occurring in the polishing process. The continuous holes as used herein refer to holes that connect to each other. On the other hand, the discontinuous holes as used herein refer to holes that are independent and not connected to other holes. The diameter of the holes is preferably from 0.001 μm to 1000 μm.
The invention is characterized in that the materials of the surface substrate and the buffer substrate are the same, namely, the elastomer, and the adhesive comprising the elastomer is used for adhering the surface substrate and the buffer substrate. As used herein, the term “elastomer,” also known as “elastic polymer,” refers to a type of polymer that exhibits rubber-like qualities. When polishing, the elastomer serves as a good buffer property to conduct and release down force applied on the polishing workpiece. In one preferred embodiment of the invention, the elastomer is foam resin. As used herein, the term “foam resin” refers to a material containing thermoplastic resin and thermodecomposing foaming agent. Preferably, the elastomer includes at least one of polyurethane (PU), polypropylene (PP), polyethylene (PE) or polyvinyl chloride (PVC); more preferably, it includes polyurethane.
In one preferred embodiment of the invention, the adhesive comprising the elastomer for adhering the surface substrate and the buffer substrate is adhesive selected from the group consisting of single-part adhesive, two-part adhesive and wet solidification adhesive. The adhesive is able to penetrate into the surfaces of the surface substrate and buffer substrate and to adhere these two substrates tightly. Furthermore, the elastomer in the adhesive has the same hardness rate and contraction rate as the surface substrate and buffer substrate, so that the conduction and release of down force occurring in the polishing process are both improved. The single-part adhesive refers to adhesive comprising high-molecule-weight elastomer served as adhesive. The two-part adhesive refers to adhesive comprising two components that interact or cross-link with each other to achieve the adherence effect. The two-part adhesive preferably comprises the elastomer and polyisocyanate. The wet solidification adhesive, also known as moisture curable adhesive, refers to adhesive where the elastomer's units cross-link to each other depending on the moisture in the air. The thickness of the adhesive for adhering the surface substrate and the buffer substrate is preferably less than 1 μm. The thin adhesive provides an excellent interface between the surface substrate and buffer substrate. In another aspect, the stress of the adhesive for adhering the surface substrate and the buffer substrate is from 5 kg/cm2 to 500 kg/cm2.
The adhesive for adhering the surface substrate and the buffer substrate can be applied in several manners. In one preferred embodiment of the invention, the elastomer for adhering the surface substrate and the buffer substrate is formed as a plurality of adhesive bumps, an adhesive film or a plurality of adhesive spots. The adhesive is not only able to adhere these two substrates, but also able to provide a proper buffer effect.
The invention also provides a method for making a carrier film for mounting a polishing workpiece, comprising the following steps of:
The manner of adhering the surface substrate and the buffer substrate varies according to the form of the adhesive. The adhesive for adhering the surface substrate and the buffer substrate is preferably applied on at least one surface of the surface substrate and the buffer substrate by coating, spraying or scraping.
In one preferred embodiment of the invention, coating the adhesive is performed with a wheel with 10 meshes to 800 meshes. The adhesive is applied on at least one surface of the surface substrate and the buffer substrate by the wheel and formed as adhesive bumps, thus avoiding excess adhesive.
In one preferred embodiment of the invention, spraying the adhesive is performed with a nozzle with a hole number between 1 and 10,000, and the hole size is between 1 μm to 1000 μm. The adhesive is applied on at least one surface of the surface substrate and the buffer substrate by the nozzle to form an adhesive thin film or spots, thus avoiding excess adhesive.
In one preferred embodiment of the invention, scraping the adhesive is performed with a blade. The adhesive is applied on at least one surface of the surface substrate and the buffer substrate by the blade to form an adhesive thin film, thus avoiding excess adhesive.
After applying the adhesive, the surface substrate and the buffer substrate are adhered. The surface substrate and the buffer substrate are preferably adhered at a pressure from 0 kg/cm2 to 10 kg/cm2. In another aspect, the surface substrate and the buffer substrate are adhered at a temperature from 0° C. to 300° C.
If necessary, the step (b) according to the invention further comprises a curing step. In some cases, the adhesive needs the curing step to solidify and form the bonding. The condition and manner of the curing step varies according to the adhesive used.
The following Examples are given for the purpose of illustration only and are not intended to limit the scope of the present invention.
Surface Substrate: Polyurethane (as elastomer) in dimethylformamide (as solvent) was coated on releasing paper and then put into a curing solution comprising water to mold the elastomer and form a surface substrate comprising holes.
Surface Processing: The surface substrate was subjected to a polishing process to form a suede-like surface.
Buffer Substrate: Polyurethane (as elastomer) in dimethylformamide (as solvent) was coated on releasing paper and then put into a curing solution comprising water to mold the elastomer and form a buffer substrate comprising holes.
Adhering: After removing the releasing paper from the surface substrate and buffer substrate, the surface of the buffer substrate was coated with two-part polyurethane adhesive with a wheel with 150 meshes. The buffer substrate was dried and attached to the surface substrate at 65° C. and 6.0 kg/cm2. The substrates were then cured at 45° C. for 48 hours to form the carrier film.
The carrier film was observed under a transmission electron microscope and shown in
While several embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention may not be limited to the particular forms as illustrated, and that all modifications which maintain the spirit and scope of the present invention are within the scope as defined in the appended claims.
