Abstract:
An apparatus for cleaning a semiconductor wafer edge is provided. The apparatus includes a film with an abrasive layer configured to contact the edge surface of a semiconductor substrate coated with a contaminant residue layer. A first reel having the film wound thereon and a second reel for receiving the film fed from the first reel are included. In one embodiment, a third reel configured to force the abrasive layer of the film against the edge surface of the semiconductor substrate so as to create an area of contact between the abrasive layer and the edge surface of the semiconductor substrate; and a pin that protrudes from to the top surface of the third reel. A system and method for cleaning a semiconductor wafer edge are also provided.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part and claims priority from U.S. patent application Ser. No. 11/172,270 filed on Jun. 29, 2005 now U.S. Pat. No. 7,115,023 and entitled “Process Tape for Cleaning or Processing the Edge of a Semiconductor Wafer,” which is incorporated herein by reference in its entirety for all purposes. 

   BACKGROUND 
   Semiconductor chip fabrication is a complicated process that involves a coordinated series of precise operations. These operations can be broadly characterized to include such steps as layering, patterning, etching, doping, chemical mechanical polishing (CMP), etc. It is well known that during the various steps in these operations, the surfaces, edges, bevels and notches of the semiconductor wafers become contaminated with a layer of residue comprised of particulates, organic materials, metallic impurities, and native oxides. The removal of these contaminants is a priority to semiconductor chip fabricators because the level of contamination on the wafer inversely correlates to the integrated circuit (IC) chip yield for each wafer and the overall reliability of those IC chips. 
   Some examples of operations that may result in unwanted wafer contamination include plasma etching (e.g., electron cyclotron resonance (ECR)) and CMP. During plasma etching, the wafer is placed in a reaction chamber and exposed to charged plasma which physically or chemically removes layers of material off the wafer surface. After the etching process is complete, a post-etch cleaning step follows whereby contaminant residue deposited on the wafer during the etching process is removed. Typically, this involves the application of chemistry to the front and back surfaces of the wafer followed by rinsing and drying. When using the optimal chemistry and tool settings, this post-etch cleaning step significantly removes or reduces the amount of post-etch contaminant residue on the wafer. 
   However, one type of post-etch residue that does not readily lend itself to removal by conventional post-etch chemical-based cleaning methods is organic polymer residue found on the wafer bevel edge, notch, and the portion of the backside of the wafer that overhangs the electrostatic chuck of the etch reactor system. This polymer residue is relatively inert and is not soluble in most known wafer-compatible chemicals. As semiconductor fabricators look towards shrinking the edge exclusion zone of the semiconductor wafer to increase the wafer&#39;s IC chip yield, it is becoming increasingly important to remove this type of residue. 
   Today, mechanical cleaning tools such as brush scrubbers and bevel edge cleaning wheels are used to remove polymer residue from the wafer. One system configuration may include the use of a plurality of rollers to hold and rotate the wafer, a double-sided scrubber that simultaneously scrubs the front and back surfaces of the wafer, and a bevel edge cleaning wheel that cleans the bevel edge of the wafer. Brush scrubbers are mechanically rotating brushes that scrub the top and back surfaces of the wafer to remove the polymer residue. Brush scrubbing is effective at removing the contaminants and certain types of residue on the front and back side of the wafer but is not effective at removing the polymer residue attached to the wafer bevel edge and notch. 
   A bevel edge cleaning wheel cleans the bevel edge of the wafer by using an abrasive wheel that rotates at a different tangential velocity than the wafer to mechanically sheer off the contaminant residue at the point of contact between the wafer bevel edge and the wheel. The difficulty with using a bevel edge cleaning wheel is that it requires an abrasive incorporated into the wheel material, which becomes worn with repeated use and therefore requires frequent replacement. Additionally, contaminant particles that are loaded onto the abrasive wheel during cleaning can become dislodged and end up as defects on the wafer. Likewise, all of the above methods and tools fail to clean the wafer notch. These shortcomings with the current methods and tools may cause greater process downtime for equipment maintenance, reduced fabrication process throughput, and decreased IC chip yield for each wafer. 
   In view of the forgoing, there is a need for a cleaning apparatus that avoids the problems of the prior art by allowing for the cleaning of both the bevel edge and notch of the semiconductor wafer. Further, there is a need for a bevel edge cleaning device that will not require frequent replacement and will not result in residue particles being dislodged onto the wafer during cleaning. 
   SUMMARY 
   Broadly speaking, the present invention fills these needs by providing an improved apparatus for cleaning the bevel edge and notch of the semiconductor wafer. It should be appreciated that the present invention can be implemented in numerous ways, including as a system, an apparatus and a method. Several inventive embodiments of the present invention are described below. 
   In one embodiment, an apparatus for cleaning a semiconductor wafer bevel edge and notch is disclosed. The apparatus includes a film with an abrasive layer configured to contact the edge surface of a semiconductor substrate coated with a contaminant residue layer. A first reel having the film wound thereon and a second reel for receiving the film fed from the first reel are included. In one embodiment, a third reel configured to force the abrasive layer of the film against the edge surface of the semiconductor substrate so as to create an area of contact between the abrasive layer and the edge surface of the semiconductor substrate; and a pin that protrudes from to the top surface of the third reel. 
   In another embodiment, a system for cleaning the bevel edge and notch of a semiconductor substrate is disclosed. The system includes a cassette with a plurality of reels that hold an abrasive film. The cassette is configured to allow the reels to orient and force the abrasive film to contact the bevel edge surface of a semiconductor substrate. The system also has at least one nozzle that applies a solution stored in a reservoir to the substrate during cleaning. The system additionally has a plurality of rollers that are configured to position and impart rotational motion to the substrate. 
   In yet another embodiment, a method is disclosed for cleaning the bevel edge surface and notch of a semiconductor substrate. The semiconductor substrate is rotated and an abrasive film is then forced against the bevel edge surface of the semiconductor substrate. Contemporaneously, a nozzle applies a solution to the interface of the abrasive film and semiconductor substrate to facilitate the removal of contaminant residue from the semiconductor substrate. In one embodiment, the abrasive film is lowered below the substrate to allow a pin to be forced against the substrate edge. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, and like reference numerals designate like structural elements. 
       FIG. 1  shows a cross-section view of a semiconductor wafer that has a layer of contaminant residue deposited on its bevel edge surface. 
       FIG. 2A  depicts a high level schematic diagram of a wafer cleaning system, in accordance with one embodiment of the present invention. 
       FIG. 2B  illustrates a cross sectional view of the abrasive film, in accordance with one embodiment of the present invention. 
       FIG. 2C  shows a side view of the wafer cleaning system, in accordance with one embodiment of the present invention. 
       FIG. 2D  is an enlarged depiction of the interface between the wafer and the abrasive film, in accordance with one embodiment of the present invention. 
       FIG. 2E  shows an enlarged depiction of the contact interface between the wafer and abrasive film in accordance with one embodiment of the present invention. 
       FIG. 2F  depicts a top view of the pin cleaning the wafer notch in accordance with one exemplary embodiment of the present invention. 
       FIG. 2G  shows a side view of the pin cleaning the wafer notch in accordance with one embodiment of the present invention. 
       FIG. 2H  illustrates a top view of an abrasive film cartridge, in accordance with one exemplary embodiment of the present invention. 
       FIG. 3A  depicts a schematic of a wafer cleaning system, in accordance with one embodiment of this invention. 
       FIG. 3B  depicts a side view of the contact interface between the wafer and abrasive film, in accordance with the embodiment shown in  FIG. 3A . 
       FIG. 4  shows a flow chart for a wafer cleaning method, according to one embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   An invention is described for apparatuses, systems, and methods for cleaning a semiconductor substrate. It will be obvious, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention. 
   The embodiments described herein provide apparatuses, systems and methods for cleaning a semiconductor substrate. A semiconductor substrate can be made of any silicon-based material. In one exemplary embodiment, the substrate is a semiconductor wafer, which is a thin slice of semiconductor material, such as a silicon crystal, upon which microcircuits are constructed by diffusion and deposition of various materials. What is disclosed by the embodiments is essentially a semiconductor substrate cleaning system that utilizes shape conforming abrasive film and an abrasive pin to clean contaminant residue off the bevel edge surface and notch of a semiconductor wafer. The terms substrate and wafer are interchangeable as used herein. 
     FIG. 1  shows a cross section view of a semiconductor wafer  101  that has a layer of contaminant residue  102  deposited on its bevel edge surface  103 . The residue  102  is typically comprised of particulates, organic materials, metallic impurities, and/or native oxides that are generated and deposited after various operations in the wafer fabrication process. 
     FIG. 2A  depicts a high level schematic diagram of a wafer cleaning system, in accordance with one embodiment of the present invention. In this particular embodiment, the wafer cleaning system  200  has a set of rollers  202  that are configured to support the wafer  101  and impart rotational velocity to the wafer  101 . In one embodiment, the rollers  202  are cylindrical drive wheels, which have longitudinal surfaces that are optimally shaped or compliant to hold the wafer  101 . Of course, a rotating chuck may also be used to rotate the wafer  101  eliminating the need for the rollers  202  altogether. It should be appreciated that the wafer  101  may be rotated in the same direction as the reels ( 204 ,  208 , and  209 ) or in opposite directions depending on the cleaning requirements of the user. The abrasive film  206  is configured to be wound onto a supply reel  209 , buttressed against one side of a stator reel  208 , and attached to a rewind reel  204 . For this embodiment, the rewind reel  204  is powered by a drive unit that controls the feed rate of the abrasive film  206  at an optimal level for removing the residue off the bevel edge  103 . The stator reel  208  is configured to force the abrasive film  206  against the bevel edge of the wafer  101 . It should be appreciated that when the stator reel  208  applies force to the point of contact between the bevel edge and the abrasive film  206 , enough force is applied to cause the abrasive film to rub the residue off from the bevel edge of the wafer  101  and the nearby edge exclusion zone of the wafer. In one embodiment, the stator reel  208 , supply reel  209  and rewind reel  204  are held in a cassette housing that can be easily replaced during maintenance performed on the wafer cleaning system  200 . Protruding from the center of the top surface of the stator reel  208  is a pin  220  that has a surface coating of abrasive material. It should be appreciated that the abrasive material has a hardness factor that is less than the hardness of the wafer  101  but greater than the hardness of the contaminant residue. 
   Still referring to  FIG. 2A , the cassette housing holding the stator reel  208 , supply reel  209  and rewind reel  204  is configured so that it can be lowered to a position that will allow the pin  220  to contact the wafer notch  203  when necessary. The notch  203  is an area on the bevel edge surface that has been removed for wafer  101  identification purposes. Positioned proximate to the interface between the bevel edge and the abrasive film  206  is a nozzle  210  that delivers chemical solution to the interface to facilitate the removal of contaminant residue from the wafer  101 . One skilled in the art will appreciate that while the delivery of the chemical solution is depicted through nozzle  210 , this is but one exemplary embodiment. That is, nozzle  210  may simply be a drip tube or any other suitable delivery mechanism commercially available. A number of different chemical solutions can be used for this purpose including: NH 4 OH (Ammonium Hydroxide), H 2 O 2  (Hydrogen Peroxide), TMAH (tetramethylammonium hydroxide), HF (hydrogen fluoride), and amine-based solvents or semiaqueous solvents (such as ST250 or ST255 supplied by ATMI). One skilled in the art will appreciate that the range of chemical solutions/reagents available for this application is vast and that the actual chemical solution utilized will depend largely on the particular application and the type of residue being removed. A pump  212  delivers the chemical solution that is stored in the chemical reservoir  216  to the nozzle  210  at a flow rate suitable for the application. It should be appreciated that many different commercially available types of pumps can be utilized to deliver the chemical solution including a peristaltic pump, gear pump, impeller pump, air pump, etc. Of course, air pressure may be used where the reservoir  216  is sealed to eliminate the need for a pump. 
     FIG. 2B  illustrates a cross sectional view of the abrasive film, in accordance with one embodiment of the present invention. In this particular embodiment, the abrasive film  206  is made up of two layers, an abrasive layer  224  and a film backing layer  226 . One skilled in the art will appreciate that while this depiction shows, a abrasive film  206  with two layers, this is but one exemplary embodiment. The abrasive film  206  can be comprised of a single layer, two or more layers, or any other suitable number of layers depending on the requirements of the user and what is commercially available. Where multiple layers are involved, it will be apparent to one skilled in the art that an adhesive may be used in between the multiple layers. 
   Still referring to  FIG. 2B , in this exemplary embodiment, the abrasive layer  224  is made up of a binder material  222  that is embedded with abradants  223 . During a cleaning operation, the stator reel forces the abrasive film  206  and the embedded abradants  223  against the semiconductor wafer. As the wafer is rotated against the abrasive film  206 , the abradants  223  dislodge the contaminant residue from the wafer. A number of different types of abradants can be used for this purpose including: alumina (Al 2 O 3 ), silica (SiO 2 ), silicon (Si), titania (TiO 2 ), ceria (CeO 2 ), silicon nitride (Si 3 N 4 ), etc. However, one skilled in the art will recognize that the abradants can be any suitable material so as long as the material has a hardness factor that is less than the hardness factor of the wafer but greater than the hardness factor of the contaminant residue. One measure of abradant hardness is the Mohs hardness scale, a comparative index of hardness where talc is defined as 1 (least hard) and diamond is defined as 10 (hardest). Using the Mohs scale, the hardness range of the abradant lies between about 3 (the approximate hardness of the contaminant residue layer) and about 7 (the wafer substrate Si, SiO 2 , Si 3 N 4 , etc.). Example abradant hardness values include titanium oxide (5.5–6.5), cerium oxide (6.5), amorphous silicon oxide (6.5–7), and silicon (7). 
   Furthermore, one skilled in the art will appreciate that while the abrasive layer  224  is shown with abradants  223  embedded, this is just one exemplary embodiment. The abrasive layer  224  can be comprised of a single material, without abradants  223  embedded, such as polyurethane, polyvinyl alcohol (PVA), polyurethane-impregnated felt, or any other commercially available material that is suitable for this particular type of application. The film backing layer  226  can be comprised of any single polymer or combination of polymers that can provide sufficient rigidity to the abrasive layer  224 . 
     FIG. 2C  shows a side view of the wafer cleaning system, in accordance with one embodiment of the present invention. Shown in this exemplary embodiment are the motorized rotational drives  252  that are attached to drive belts  256  which are in turn attached to the rollers  202 , the stator reel  208 , and the rewind reel  204 . The rollers  202  support the wafer  101  and are powered by the motorized rotational drives  252  to impart a rotational velocity to the wafer  101 . The controller  254  communicates with the motorized rotational drives  252  to set the rotational velocity for the rollers  202 , stator reel  208  and rewind reel  204 . In this embodiment, the motorized rotational drive  252  attached to the rewind reel  204  drives the rewind reel, which pulls the abrasive film  206  across the stator reel  208  at a set feed rate. The feed rate is selected for optimal removal of the contaminant residue on bevel edge of the wafer  101  and to optimize the lifespan of the stator reel  208 . One skilled in the art will appreciate that while this depiction shows the stator reel  208  and rewind reel  204  as being attached to the motorized rotational drives  252 , any combination of the stator reel  208 , rewind reel  204 , and supply reel (not shown in this depiction) can be attached to a motorized rotational drive  252 . It should also be noted that in some embodiments, the stator reel  208 , rewind reel  204 , and supply reel will be housed in a cassette format to allow for easy removal and change out during maintenance of the wafer cleaning system.  FIG. 2C  represents one exemplary drive system, and it will be apparent to one skilled in the art that other drive systems may be employed with the embodiments described herein. 
     FIG. 2D  is an enlarged depiction of the interface between the wafer and the abrasive film, in accordance with one embodiment of the present invention. In this exemplary embodiment, the stator reel  208  forces the abrasive film  206  against the bevel edge surface of the wafer  101 . The longitudinal surface of the stator reel  208  has a concave shape that conforms to the shape of the bevel edge surface of the wafer  101  allowing the stator reel to accept the wafer  101 . When the wafer  101  is rotated against the abrasive film  206 , the rubbing of the wafer  101  and the abrasive film  206  dislodges the contaminant residue from the bevel edge surface. As one skilled in the art may appreciate, while this depiction shows the abrasive film  206  having full contact with the surface of the stator reel  208 , the abrasive film  206  may be held so that the abrasive film only contacts the stator reel  208  at the top and bottom edges of the stator reel. 
   Still referring to  FIG. 2D , the nozzle is positioned to face the bottom edge surface of the wafer  101  near the interface between the abrasive film  206  and the wafer  101 . In this exemplary embodiment, the nozzle  210  sprays a chemical solution against the bottom edge surface of the wafer  101  proximate to an interface defined by the bevel edge of the wafer  101  and the abrasive film  206 . As one skilled in the art would appreciate, the nozzle  210  set-up in this depiction is but one exemplary embodiment. One or more nozzles  210  can be used and the positioning of the nozzle(s)  210  can be changed depending on the cleaning requirements of the user. For example, in yet another embodiment, a nozzle  210  can be placed facing the bottom bevel edge surface of the wafer  101  and proximate to where the bevel edge surface emerges from contact with the abrasive film  206 . Here, the nozzle can be used to spray a chemical solution such as ultrapure deionized water (DIW) to rinse away contaminant residue dislodged by the rubbing of the abrasive film  206  against the wafer bevel edge. 
     FIG. 2E  shows an enlarged depiction of the contact interface between the wafer and abrasive film in accordance with one embodiment of the present invention. In this particular embodiment, a stator reel  262  has a top surface  264  that has a smaller diameter than the bottom surface  266 . Nozzles  210  face both the top and bottom surface of the wafer  101  proximate to the interface between the wafer  101  and the abrasive film  206 . The longitudinal surface of the stator reel  262  is sloped and curved starting from the top surface  264  continuing down towards the bottom surface  266 . During the operation of this particular embodiment, the stator reel  262  forces the abrasive film  206  against the bottom edge of the wafer  101  resulting in the abrasive film  206  being pressed against the sloped surface of the stator reel  262 . When the wafer  101  is rotated against the abrasive film  206 , the rubbing of the wafer  101  and the abrasive film  206  dislodges the contaminant residue from the bevel edge surface. 
   Still referring to  FIG. 2E , the nozzle  210  facing the top surface of the wafer sprays a chemical solution against the interface between the abrasive film  206  and the wafer  101  to facilitate the removal of the contaminant residue from the wafer  101 . The bottom nozzle  210  sprays a chemical solution against the bottom bevel edge surface of the wafer  101  after the area of contact between rubbing against the abrasive film  206  and the bevel edge of the wafer. This is to remove any dislodged contaminant residue particles remaining on the wafer  101  surface from the cleaning operation. 
     FIG. 2F  depicts a top view of the pin cleaning the wafer notch in accordance with one exemplary embodiment of the present invention. In this particular embodiment, there is a pin  220  with an abrasive surface layer protruding from the top surface of the stator reel  208 . Nozzle  210  is positioned near the interface of the pin  220  and wafer notch  203 . As one who is skilled in the art would appreciate, the abrasive layer of pin  220  may be comprised of a single material or a combination of different materials as discussed above with reference to  FIG. 2B . As mentioned above, the resultant abrasive layer has a hardness factor that is less than the hardness factor of the wafer but greater than the hardness factor of the contaminant residue. 
   Still referring to  FIG. 2F , during the wafer notch  203  cleaning operation, the stator reel  208  is lowered below the rotational plane of the wafer  101  and the pin  220  is forced against the wafer notch  203  by the stator reel  208 . As the pin  220  is rotated, the abrasive layer rubs against the wafer notch  203  surface which dislodges the contaminant residue that is on the surface of the wafer notch  203 . The nozzle  210  sprays a chemical solution on the wafer notch  203  during the notch cleaning operation to facilitate the removal of the contaminant residue. In another exemplary embodiment, the nozzle  210  can spray a chemical solution after the pin  220  is positioned away from the wafer notch  220 , to remove any loose contaminant residue particles. 
     FIG. 2G  shows a side view of the pin cleaning the wafer notch in accordance with one embodiment of the present invention. In this embodiment, the stator reel  208 , rewind reel  204 , and supply reel  209  are lowered relative to the position of the wafer  101  to allow the pin  220  to contact the wafer notch. This can be accomplished using a variety of means including spring-loaded action, mechanical drives or any other suitable mechanism for moving the pin  220  into the proper position for cleaning the wafer notch  203 . A person having ordinary skill in the art will appreciate that while the reels are depicted as having been lowered in relation to the wafer  101 , this is not the only way the pin  220  can be positioned to contact the wafer notch. That is, the wafer  101  may also be raised in relation to the stator reel  208  then pushed against the pin  220  so that the notch is cleaned by the pin  220  as the wafer and pin rotate. 
     FIG. 2H  illustrates a top view of an abrasive film cartridge, in accordance with one exemplary embodiment of the present invention. In this embodiment, the stator reel  208  is positioned in the open corner, the supply reel  209  is positioned in the left corner, and the rewind reel  204  is positioned in the right corner of the cartridge  272 . The cartridge  272  opening enables the abrasive film on the stator reel  208  to come into contact with the bevel edge of a wafer  101  during wafer cleaning. The cartridge  272  is designed to be easily removed and installed to the motorized drives of the wafer cleaning system. The reels are rigidly supported by the cartridge frame  274  using methods that are well known in the art and will not be described in detail herein. 
     FIG. 3A  depicts a schematic of a wafer cleaning system, in accordance with one embodiment of this invention. In this particular embodiment, a supply reel  284  is positioned above the wafer  101  and a rewind reel  282  is positioned below the wafer  101 . Powered rollers  202  impart rotational velocity to the wafer  101 . An abrasive film  206  is held in between the reels and forced against the wafer bevel edge in a substantially orthogonal orientation to the rotational plane of the wafer  101 . A nozzle  210  is positioned proximate to the interface between the wafer bevel edge and the abrasive film  206 . The supply reel  284  and the rewind reel  282  are attached to motorized drive units  302  that control the feed rate of the abrasive film  206  at an optimal level for removing contaminant residue off the bevel edge surface. For example, the feed rate of the abrasive film  206  may be set at a rate wherein the bevel edge is continually exposed to abrasive film having a minimum level of available abradant. Of course, the feed rate of the abrasive film  206  will be dependent on the rotational velocity of the wafer  101 . Of course, only one of the motorized units  302  needs to be engaged during cleaning. The plane of rotation of the supply reel  284  and the rewind reel  282  is orthogonal to that of the plane of rotation of the wafer  101 . One skilled in the art will appreciate that while the abrasive film  206  is depicted here as being forced against the wafer bevel edge surface, this is but one exemplary embodiment. That is, the wafer can just as easily be maneuvered so that its bevel edge surface is forced against the abrasive film  206  held in between the supply reel  284  and rewind reel  282 . 
   Still referring to  FIG. 3A , the nozzle  210  is positioned so that it sprays a chemical solution onto the interface between the wafer bevel edge surface and the abrasive film  206  to facilitate the removal of the contaminant residue. One additional benefit derived from spraying chemical solution against the wafer  101  is that it rinses off contaminant residue dislodged by the friction of the abrasive film  206  against the wafer bevel edge. 
     FIG. 3B  depicts a side view of the contact interface between the wafer and abrasive film, in accordance with the embodiment shown in  FIG. 3A . As shown in this particular embodiment, an abrasive film  206  is held in between a supply reel  284  and a rewind reel  282 . When the reels are drawn towards the center of the wafer  101 , the abrasive film  206  conforms around the bevel edge surface of the wafer  101  and may contact more of the edge exclusion zone. As the wafer  101  rotates, the abrasive film  206  rubs against the bevel edge surface of the wafer  101  dislodging the contaminant residue attached to the wafer bevel edge. During the wafer cleaning operation using this particular embodiment, the abrasive film  206  pre-wound onto the supply reel  284  advances as it is wound onto the rewind reel  282 . The feed rate of the abrasive film  206  is optimized for removing contaminant residue from the wafer bevel edge surface and preventing wear and tear on the reels. Both reels,  282  and  284 , are designed to be easily replaced during routine equipment maintenance. 
     FIG. 4  shows a flow chart for a wafer cleaning method, according to one embodiment of the present invention. An exemplary schematic diagram of the wafer cleaning system utilized in this method is shown in  FIGS. 2A and 2C . The method  400  starts with operation  402 , where the wafer is loaded onto the wafer cleaning system and rotated at a set rotational velocity. The rotational velocity may be imparted using powered rollers in one embodiment. The method  400  then proceeds to operation  404 , where an abrasive film is forced against the bevel edge surface of the wafer  101 . For example, a stator reel may be used to force the abrasive film against the bevel edge. Next, the method  400  moves to operation  406 , where a nozzle applies a chemical solution to the interface between the bevel edge surface of the wafer and the abrasive film to facilitate the removal of the contaminant residue. After operation  406 , the method  400  proceeds to operation  408 , where the abrasive film is lowered to a position below the wafer to allow the pin to contact the wafer notch. As mentioned with reference to  FIG. 2C , a stator reel which guides the abrasive film may be lowered and moved toward a center of the wafer to enable the pin to contact the bevel edge and notch. Finally, during operation  410  the pin is forced against the wafer notch to dislodge the contaminant residue deposited on the notch. Of course, the pin may be rotated. This method  400  is performed, as detailed in the sequence of operations above, on every wafer  101  that is cleaned using this particular embodiment of the present invention. 
   Although a few embodiments of the present invention have been described in detail herein, it should be understood, by those of ordinary skill, that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details provided therein, but may be modified and practiced within the scope of the appended claims.