Patent Application
20130199705
The present specification generally relates to methods of polishing metal surfaces, and more particularly to methods of polishing metal surfaces of barrier doors of gate valves used in semiconductor cluster tools.
In vacuum processing of thin film materials, such as in the manufacture of semiconductor devices, multiple processing modules are typically interfaced to permit transfer of wafers between the interfaced processing modules. The transfer of wafers between interfaced processing modules is typically accomplished with the help of transport modules, which typically move the wafers through slots or ports provided in the adjacent walls of the interfaced processing modules. Transport modules may be used in conjunction with a variety of processing modules, which may include, among others, semiconductor etching systems, material deposition systems, and flat panel display etching systems. The particular arrangement of transport modules and processing modules is frequently referred to as “cluster tool architecture.”
In semiconductor process cluster tool architecture, the pressure within the transport module may be different than the pressure within an adjacent processing module. A gate drive valve may be used to isolate the various modules to: minimize leaks between a transport module that is at a different pressure than a processing module; minimize leaks between modules during pressure varying transitions; or to seal off a processing module from a transport module during processing.
In order to isolate a particular module, a gate valve may include a seal plate and a barrier door that seals off the particular module when engaged by the barrier door. The barrier door may include a vacuum seal that extends about the periphery of the door and a surface finished barrier seal face. The seal plate may include a barrier seal and a vacuum seal face. When the barrier door engages the seal plate in order to isolate the particular module, the vacuum seal of the barrier door may engage the mating vacuum seal face of the seal plate and the barrier seal of the seal plate may engage the mating barrier seal face of the barrier door. The seal plate sealing surfaces may be integrated into the chamber design, thus not requiring a separate seal plate, and the seal surfaces would be the chamber housing surfaces.
The barrier door may be fabricated from a metal, such as aluminum, by a process that involves anodizing the barrier door. Yet, such barrier doors can be prone to microcrack of the anodized surface thereby compromising the electrical and corrosive resistance of the anodized surface.
Accordingly, a need exists for additional methods of preserving the anodized metal surface of gate valve barrier doors.
The method of preserving an anodized finish on a metal surface of a barrier door for a gate valve in a process module is described. According to one embodiment, the method can include bonding a seal to the metal surface, anodizing the metal surface, and then polishing the seal surface. The seal surface is polished by traversing a polishing path along the seal surface with a polishing head maintaining frictional contact with the seal surface. The seal integrity is maintained by bounding the polishing head to skirt the edge of the seal by following the polishing path. By following the polishing path, the polishing head can polish the seal surface immediately adjacent to the seal without touching or damaging the seal.
According to another embodiment, the anodized finished is preserved by applying the high temperatures needed to vulcanizing an elastomer seal to the metal surface of a barrier door before the anodize process. The metal surface is anodized after vulcanization and the seal surface is polished. The seal surface is polished by traversing a polishing path along the seal surface with a polishing head maintaining frictional contact with the seal surface. The seal integrity is maintained by bounding the polishing head to skirt the edge of the seal by following the polishing path and polishing the seal surface immediately adjacent to the seal without touching or damaging the seal.
These and additional features provided by the embodiments described herein will be made more fully understandable in view of the following detailed description, in conjunction with the drawings.
The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
a-c depicts several paths the polishing head can follow along a metal surface, according to one or more embodiments shown and described herein.
In the present disclosure, the process of preserving an anodized metal surface involves curing the seal first, then anodizing the metal surface, and finally polishing the surface. Depending on the type of seal used, the curing process could require vulcanizing the vacuum seal to barrier door which requires high curing temperatures for an extended period of time (e.g., a pre-cure stage at temperatures of about 350° F. to about 370° F. for about five minutes and a final cure at temperatures about 400° F. for about 24 hours). The barrier door is then anodized. The final step of polishing can be accomplished via a computer numerical control (CNC) machine, polishing in an omni-directional direction, and using a polishing head. A method of polishing metal surfaces that require high temperature curing and anodized metal surfaces will be described in more detail herein.
In order to transfer a wafer from the first processing module 106a to the second processing module 106b, for example, a robotic arm within transport module 102 may reach into the first processing module 106a, pick up the wafer to be transported, and move the wafer through a slot or port in the adjacent wall of the first processing module 106a, through an opening in the valve 104a, through the interior of the transport module 102, through an opening in the second valve 104b, and finally through the adjacent wall of the second processing module 106b. While the semiconductor process cluster tool architecture 100 depicted in
The first valve 104a typically functions to isolate the first processing module 106a and the transport module 102 from one another in order to minimize leaks when it is desirable to isolate the modules, e.g., during pressure varying transitions, or to seal off the first processing module 106a from the transport module 102 during processing in the first processing module 106a. Similarly, the second valve 104b typically functions to isolate the second processing module 106b and the transport module 102 from one another in order to minimize leaks when it is desirable to isolate the modules, e.g., during pressure varying transitions, or to seal off the second processing module 106b from the transport module 102 during processing in the second processing module 106b.
Still referring to
The first valve 104a includes a transport module wall 134, a processing module wall 132, a processing module barrier door 110, a transport module door 112, a carrier 114, and a shaft 116, an opening 136P, and an opening 136T. The opening 136P is provided in the processing module wall 132 in order to permit wafers (not shown) to be transferred into and out of the first processing module 106a. Similarly, the opening 136T is provided in the transport module wall 134 in order to permit wafers (not shown) to be transferred into and out of the transport module 102. The opening 136P is generally rectangular in shape and is smaller in each dimension than the generally rectangular shape of the processing module barrier door 110, which is provided for sealing the opening 136P. The opening 136T is also generally rectangular in shape and is smaller in each dimension than the generally rectangular shape of the transport module door 112, which is provided for sealing the opening 136T.
In some embodiments, the corners of the processing module barrier door 110, the transport module door 112, the opening 136P, and the opening 136T are rounded, thus resulting in the “generally rectangular” shape referred to in the preceding paragraph. In other embodiments, the corners of the barrier doors and openings may not be rounded. In still other embodiments, the barrier doors and openings may be formed to have a shape other than rectangular.
a-c depict a top down view of the process module barrier door 110 along with the vacuum seal 120, barrier seal surface 150, and the interior face 160. In
Referring now to
Referring now to
The polishing head can be equipped with a backing pad and grit paper of various abrasiveness and material make-up; a buffing pad and an abrasive compound or abrasive slurry; a router bit; or any other tool or material that is designed to polish a surface. The polishing head can move the abrasive material in a circular motion, an orbital motion, or lock in place.
The polishing head engages the barrier door at the precise pressure required by the combination of the hardness of the metal composition of the barrier door and the type and abrasiveness of the grit to achieve the proper polish on the metal surface or anodize surface.
It should be appreciated that the precision of the CNC machine allows the polishing head to skirt the edge of the vacuum seal by tracing without touching or physically damaging the vacuum seal on the barrier door. A protective film or cover can be placed over the vacuum seal to protect the vacuum seal from the polishing head.
It should be appreciated that the vacuum seal could be a removable o-ring or a bonded seal through vulcanization. The vacuum seal could be made from rubber or fluoroelastomer or perfluoroelastomer or any other elastomer. Furthermore, the process module barrier door can be made of any type of metal to include aluminum, more specifically, type 6061-T6XX aluminum. The embodiments described herein are not limited to the process module barrier door or the processing module. The barrier seal could be made from a chemically inert material, more specifically, PFA. Since chemically inert plastics typically have low relative elastic properties, seals utilizing such materials typically have an inner elastic energizer, more specifically, an elastomeric material such as silicone or Viton, or a metallic spring energizer. When the application of the barrier seal is sensitive to metallic materials, the elastomeric energizer is preferred over the metallic spring energizer. A seal of this type is often referenced as a solidcore PFA encapsulated seal.
It is noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 61/595,719 filed Feb. 7, 2012, entitled “METHOD OF POLISHING A METAL SURFACE OF A BARRIER DOOR OF A GATE VALVE USED IN A SEMICONDUCTOR CLUSTER TOOL ARCHITECTURE.”
| Number | Date | Country | |
|---|---|---|---|
| 61595719 | Feb 2012 | US |
