Patent Application
20090113684
The present invention generally relates to the construction of vacuum processing chambers used for processing substrates, and more specifically to techniques for uniformly compressed sealing members for slit valve doors with angled corners.
In general, vacuum processing chambers for processing substrates include a substrate transfer opening, commonly known as a slit valve. A slit opening, a tunnel-like passage associated with the slit valve, is used to transfer substrates between a process chamber, also called a reactor chamber, and a transfer chamber. The slit valve opening is commonly sealed at an outside surface of the process chamber body by a blocking plate which moves over the slit valve opening. This blocking plate is a conventional slit valve door. An o-ring is generally attached to the conventional slit valve door to provide a seal.
In a conventional vacuum processing chamber, the slit valve door may have angled corners. When closing such a slit valve door, the angled corners of the slit valve door are aligned by angled corners of the slit valve seat. To provide alignment, the dimensions of the seat are sized smaller, generally by at least about 0.008 inches on each of the two sides used for alignment, than the slit valve door. However, this implementation results in tensile (and shear) stresses. As shown in
When a conventional slit valve door is in the closed position, the o-ring generates particle contaminants at the angled corners of the slit valve door. These particles can contaminate the process chamber and damage substrates. Until now there has been no satisfactory solution to overcome o-ring contaminants for a slit valve door with angled corners, in that conventional vacuum processing chambers are constructed in a configuration that gives rise to particles from o-rings in the process chamber.
The present invention recognizes that the severity of chemical attack on the sealing member is dependent on the level of tensile (or shear) stress on the sealing member. In conventional systems, where high localized stresses are present at the angled corners, the chemical attack is accelerated. Embodiments of the present invention provide techniques for a door system with angled corners for sealing an opening between two chambers in a semiconductor processing system. The slit valve door is sized to apply substantially uniform seal compression to the sealing member when in the closed position. In this way, the stress experienced by the sealing member at the angled corners is substantially reduced, and so is the chemical attack. Consequently, degradation of the sealing member is diminished and particle contamination is decreased.
According to an embodiment of the present invention, the door system for sealing an opening on a plane between two chambers in a semiconductor processing system where the opening has at least one angled corner, includes a door, actuator, and sealing member. The door is moveable in the plane and has at least one angled corner to align the door with the opening. The actuator moves the door to selectively open and close the opening. The sealing member seals the opening when the door is in a closed position. The door is sized to apply substantially uniform seal compression to the sealing member when in the closed position.
According to an another embodiment, a system for sealing an opening on a plane between two chambers in a semiconductor processing system is provided. The system includes a sealing member disposed along a border of the opening and means, moveable in the plane of the opening between an open position and a closed position, for applying a substantially uniform seal compression to the sealing member to seal the opening in the closed position.
According to yet another embodiment, a method of performing a semiconductor manufacturing process in at least one chamber. A substrate is placed in a chamber. A door is provided, as well as a sealing member between the door and an opening of the chamber. The door is moved to close the opening. Substantially uniform sealing pressure is applied to the sealing member.
The foregoing, together with other features, embodiments, advantages of the present invention, will become more apparent when referring to the following specification, claims, and accompanying drawings.
a) and 5(b) are cross-sectional views of the slit valve door according to an embodiment of the present invention in an open and closed position, respectively.
Embodiments of the present invention provide techniques for a door system for sealing an opening between two chambers in a semiconductor processing system and, more particularly, techniques to substantially reduce particle contaminants from a slit valve o-ring with angled corners due localized stresses. The inventors recognize that slit valve o-rings, generally perfluoro elastomers, are chemically attacked more severely when under tensile (or shear) stress by chemical species used during the chamber cleaning process, such as fluorine and nitrogen trifluoride (NF3). Accordingly, the present approach diminishes, or avoids, localized shear stresses by providing uniform compression to the sealing member. Other techniques to reduce particle contaminants resulting from o-ring chemical attack are discussed in U.S. Provisional Patent Application No. 60/576,737, filed Jun. 2, 2004, entitled “Variable Seal Pressure Slit Valve Doors for Semiconductor Manufacturing Equipment” (Attorney docket No. A8822T546), which is incorporated herein by reference for all purposes.
Slit valve 206 has a slit valve door 208 movable in a direction generally parallel to the plane of the slit valve opening 216. Rods 212 connect slit valve door 208 to the pneumatic actuator 210. In order to move rods 212, and thus slit valve door 208, the pneumatic actuator 210 applies or relaxes sealing pressure to rods 212.
Pressurized gas is provided to pneumatic actuator 210 from pressurized gas source 214. The pressure level supplied by the pressurized gas source 214 is at least the maximum pressure level needed by vacuum processing chamber system 200. Pressurized gas source 214 can typically provide gas at about 80 psi to about 90 psi since semiconductor fabrication facilities generally provide pressurized gas lines operating at about 80 psi to about 90 psi.
a) illustrates slit door 208 in an open position to allow substrates to pass between transfer chamber 202 to process chamber 204 through the slit valve opening 216.
b) illustrates slit door 208 in a closed position to seal transfer chamber 202 from process chamber 204. Rods 212, which pass through travel tubes 304, are attached to slit door 208. To close slit door 208, rods 212 are extended by pneumatic actuator 210.
To prove the principle and operation of the present invention, the inventors performed experiments. These experiments were merely examples and should not unduly limit the scope of the inventions defined by the claims herein. One of ordinary skill in the art would recognize many other variations, modifications, and alternatives. Uniformly compressed sealing members for slit valve doors were demonstrated. Slit valve seats providing 0.004 inches and 0.003 inches of compression were machined and tested under conditions simulating a wafer deposition process and a chamber clean process. During the deposition and chamber clean processes, the pressure gradients between the process and transfer chambers were approximately 760 torr and 10 torr, respectively. While monitoring the slit valve doors for leaks, the sealing pressures applied to the slit valve doors were adjusted from 5 psi to 25 psi in increments of 5 psi. The results of the results of these experiments are provided below in Table 1.
As can be seen in Table 1, slit valves configured to provide uniform compression to the sealing member can seal a slit valve opening between two chambers in a semiconductor processing system during deposition processing. Meanwhile, the sealing pressure is uniformly distributed along the entire edge of the slit valve seat, thereby avoiding the localized stresses recognized by the inventors in conventional systems. The inventors have found that the reduction of these localized stresses increases the longevity of sealing members and reduces particle contaminants created by sealing members. In fact, an embodiment of the present invention has extended the lifetime of a sealing member from about 3000 to greater than 12000 wafer cycles.
Although specific embodiments of the invention have been described, various modifications, alterations, alternative constructions, and equivalents are also encompassed within the scope of the invention. The described invention is not restricted to operation within certain chamber processing environments, but is free to operate within a plurality of processing environments. Additionally, although the present invention has been described using a particular series of steps, it should be apparent to those skilled in the art that the scope of the present invention is not limited to the described series of steps.
Further, while the present invention has been described using a particular combination of hardware and software in the form of control logic and programming code and instructions, it should be recognized that other combinations of hardware and software are also within the scope of the present invention. Aspects of the present invention may be implemented only in hardware, or only in software, or using combinations thereof.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
The present application is a Divisional of Ser. No. 11/003,115 filed Dec. 3, 2004, which application claims the benefit of U.S. Provisional Appln. Nos. 60/576,834 and 60/576,737 both filed Jun. 2, 2004; the full disclosures of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60576834 | Jun 2004 | US | |
| 60576737 | Jun 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11003115 | Dec 2004 | US |
| Child | 12253716 | US |
