The invention relates generally to the field of reticle processing, and specifically to apparatus used to carry said reticles and methods of using the same.
Reticles must be carried during multi-step chemical treatment processes and must be reliably transferred between different treatment locations in such processes. While reticle carriers exist that have been used to support reticles during processing, they all suffer from one or more disadvantages. For example, some reticle carriers have high chemical drag from a process tank to a rinse tank, thereby increasing the chemical and water consumption. Other reticle carriers do not have good flow dynamics or exhibit large shadowing of sonic energy which is often employed in reticle treatment processes. Some reticle carriers have large reticle contact areas which increases the risk of contamination and can trap chemicals.
Additionally, reticle carriers can be subjected to high temperatures during reticle processing. Existing reticle carriers can experience unwanted deformation and/or creep. Moreover, because of the materials of which some reticle carriers are constructed, the reticle carriers can either contaminate the reticles and/or can not withstand high processing temperatures.
It is therefore, an object of the present invention to provide a reticle carrier that is both durable and resistant to chemicals.
Another object of the present invention to provide a reticle carrier that optimizes load carrying capacity while minimizing the fluid flow obstruction during processing.
Still another object of the present invention to provide a reticle carrier that enhances the drying cycle of reticles.
Yet another object of the present invention to provide a reticle carrier that affords reliable transfer of reticles at high robot speeds.
A further object of the present invention to provide a reticle carrier that reduces reticle contact area to reduce the trapping of contaminates and/or process fluids.
A yet further object of the present invention to provide a reticle carrier that minimizes thermal expansion.
A still further object of the present invention to provide a reticle carrier that reduces chemical drag from one tank to another.
It is also an object of the present invention to provide a reticle carrier that reduces process and rinse cycle times.
Still another object of the present invention to provide a reticle carrier that minimizes sonic energy shadowing and/or that provides for complete sonic energy coverage of reticles positioned therein.
A further object of the present invention to provide a reticle carrier that provides support rods that are removable for easy replacement.
These and other objects are met by the present invention which, in one aspect is an apparatus for carrying reticles comprising: a structural frame carrying at least three holding rods; the rods constructed of a hard inner core material and a chemically resistant outer material.
The frame preferably comprises a substantially flat front panel, a substantially flat back panel opposing the front panel, and two substantially flat side panels connecting the front and back panels. In this embodiment, the front panel, the back panel, and the two side panels are preferably oriented substantially vertical so as to minimize fluid flow obstruction. The top surface of each of the two side panels can be curved or angled to minimize chemical drag.
Similar to the rods, the frame can also be constructed of a hard inner core material and a chemically resistant outer material. The hard inner core material of the frame and the rods can be selected from a variety of materials, such as quartz, ceramic, PEEK, and silicon carbide. The outer material of the frame and the rods can be a fluoropolymer, such as PTFE, PFA, and ECTFE. The apparatus is preferably adapted to withstand a reticle treatment process temperature between 20-180° C.
It is preferred that each rod have a plurality of slots for receiving and supporting reticles in a substantially vertical position. In this embodiment, the rods are oriented in the frame so that the slots on the rods are aligned. The rods can be generally circular or elliptical in cross-section and the slots preferably extend around the entire perimeter of the rods, forming a groove.
In order to minimize contact are between reticles and the apparatus, the slots can be provided with angled walls that contact and support edges of a reticle positioned therein. It is further preferable that the rods comprise at least one bottom holding rod and at least one side holding rod. Most preferably, two bottom holding rods and two side holding rods are supplied. In this embodiment, the slots on the side holding rods will have a ridge located at the bottom of the slots so that when a reticle is loaded therein, the reticle will contact only the angled walls and the ridge. The slots on the bottom holding rod also have angled walls so that when a reticle is position therein, the reticle only contacts the angled walls.
The apparatus is preferably adapted to support a load of 1 to about 10 reticles. The side holding rods are preferably generally circular in cross-section as well as the bottom holding rods. The bottom holding rods are adapted to carry more weight than the side holding rods. The side holding rods are located in a position to guide carried reticles so as to prevent the carried reticles from leaning against each other.
The apparatus also can comprise means for a robotic device to pick the apparatus up at three points, wherein the points are arranged so the apparatus is stable and can be transferred at high robotic speeds. All of the rods preferably comprise a means for locking and unlocking the rods to the frame, and thus, are removable from the frame.
The rods and the frame are preferably designed to minimize shadowing effects on reticles supported in the apparatus and being exposed to megasonic energy. The frame can also comprise means to facilitate proper alignment of the apparatus in a process tank. Finally, the two bottom holding rods can be connected to the frame so that one of the rods is at a lower position than the other rod so that when a reticle is loaded into the apparatus, a top edge of the reticle is at an incline (from side to side).
In another aspect, the invention is a method of processing reticles comprising: providing an apparatus comprising a structural frame carrying at least three holding rods, the rods constructed of a hard inner core material and a chemically resistant outer material; loading at least one reticle into the apparatus; positioning the apparatus and loaded reticles in a process chamber; and performing a first reticle treatment process to the loaded reticles. The method can further comprise performing a second reticle treatment process to the loaded reticles without removing the reticles from the apparatus.
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Moreover, frame 10 is designed so that its mass and surface area is minimized, thus reducing the chemical drag between process tanks and to a rinse tank. Reducing chemical drag from tank to tank, in turn, reduces chemical consumption, enhances rinsing of the reticles 50, conserves water consumption, and significantly reduces cross contamination between tanks, thereby reducing the process and rinse cycle times. Openings 15 are provided in front and back panels 11 and 12 to further contribute to the achievement of these goals.
Additionally, the top surface 16 of side panels 13 and 14 are created so as to be curved. Specifically, the top edge surfaces 16 have cross-sectional profiles that are semi-circular. By not making the top surfaces 16 of side panels 13 and 14 a substantially horizontal flat surface, the amount of fluids that get trapped on these surfaces during removal from chemical baths is further decreased. While the top surfaces 16 are illustrated as being curved, it is possible to achieve this goal by shaping a variety of shapes, such as an apex, a single angle, or other non-concave and/or horizontally flat surfaces. Moreover, any and/or all of the top surfaces present on the frame 10 can be so shaped, including specifically all of the top surfaces of front and back panels 11 and 12.
Rods 20-23 and frame 10 of reticle carrier 100 are constructed of a “hard” inner core material surrounded by a chemically resistant outer material. Suitable “hard” inner core material include carbon fiber, quartz, ceramic, PEEK or silicon carbide. The chemically resistant outer material is preferably a coating of fluoropolymer material, such as for example PTFE, PFA, TFM or ECTFE. However, those skilled in the art will appreciate that other materials can be used. By constructing reticle carrier 100 as such, a metal-free, high temperature apparatus is formed that will withstand thermal cycling with no significant creep deformation. The holding rods 20-23 can support a load of typically 1 to 10 reticles at a process temperature up to 180° C. without experiencing deformation or substantial creep.
Reticle carrier 100 comprises four holding rods 20-23. However, the invention is not so limited and can be constructed with as many holding rods as is needed, so long as a minimum of three rods are used. Holding rods 20-23 are positioned accordingly to support the applied load from the reticles.
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The structural component of reticle carrier 100 is provided by frame 10, which is designed to provide rigidity to reticle carrier 100. The hard inner core material of frame 10 is preferably constructed of quartz to provide the highest possible purity. However, other materials can be selected to provide strength and purity. Also, other shapes could be considered as long as the strength and the fluid flow dynamics are not compromised. All surfaces of frame 10 are over-coated with a high purity fluoropolymer.
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However, in order to avoid water or other chemicals from getting trapped on the top edge/surface of the reticles 50, bottom holding rod 23 is located in frame 10 at a lower position than is bottom holding 22. Thus, when reticles 50 are loaded and supported in reticle carrier 100, the reticles 50 are slightly tilted, allowing water and other chemicals to easily slide off.
The holding rods 20-23 are designed to support a load of typically 1 to 10 reticles 50 (6″×6″×0.25″ in size) at a process temperature up to 180° C. Side holding rods 20, 21 have a generally circular cross-section. However, because most of the load will be resting on bottom holding rods 22, 23, bottom holding rods will be designed so as to have a greater load bearing capacity. For example, the hard inner core material can be made thicker. Alternatively, bottom holding rods 22, 23 can be designed to have an elliptical cross-section having a major and a minor axis. In order to optimize load carrying capacity in this embodiment while minimizing fluid flow obstruction, the major axis of the elliptical cross-section is aligned in the load bearing direction, which in the illustrated case would be vertically for bottom holding rods 22, 23. The maximum initial deflection at room temperature through 180° C. for bottom holding rods 22, 23 is designed to be less than 0.007 inches in the direction of the load.
Regarding the detail of the holding rods 20-23, bottom holding rods 22, 23 comprise a plurality of support slots 60 for receiving and supporting loaded reticles 50. Similarly, side holding rods 20, 21 comprises a plurality of guide slots 61 for guiding and supporting loaded reticles 50. Support slots 60 and guide slots 61 are positioned on bottom holding rods 22, 23 and side holding rods 20, 21 respectively so that the slots 60, 61 are aligned so that they can support a plurality of reticles 50 in a substantially vertical orientation.
The geometries of slots 60, 61 are designed to provide minimum and soft contact (1-3 mm depth) with reticles 50 and will be molded into the fluoropolymer over-molding (i.e. the chemically resistant outer material). While the geometries of support slots 60 are different from guide slots 61, as will be discussed in detail below, both geometries are designed for minimal (line) reticle contact area and are free of pockets that can trap contaminates and/or process fluids. Both geometries also provide optimum liquid drying at the contact areas and allow the reticles 50 to be held only at their edges, thus minimizing the edge exclusion to an absolute minimum. This is a desired feature during reticle manufacturing or servicing as part of the IC (integrated circuits) manufacturing.
When loaded into reticle carrier 100, each reticle 50 is supported with only two points of contact, one at each of the bottom holding rods 22, 23. In addition, each reticle 50 is held by the two side holding rods 20, 21 for stability and to prevent the reticles 50 from moving and touching each other.
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Additionally, semi-circular opening 80, 81 are provided in front panel 11 and back panel 12 of frame 10 respectively. Opening 80, 81 provide a means by which the positioning of reticle carrier 100 can be ensured within a process tank. For example, the process tank can comprise a tube on it bottom that mates with openings 80, 81, thereby ensuring proper processing alignment.
As mentioned above all of the surfaces of the hard inner core material of reticle carrier 100 are over-coated with a high purity fluoropolymer. This combines chemical resistance and purity of the most advanced high performance fluoropolymers with the structural integrity and thermal performance of high temperature polymer composites. Moreover, thermal expansion of reticle carrier 100 is held to an absolute minimum.
Reticle carrier 100 provides a number of advantages over prior art carriers. Holding rods 20-23 are designed with low profile design for minimal reticle contact area and superior process fluid flow are used. Specifically, the design of bottom holding rods 22, 23 provide for optional stiffness with minimal flow restrictions. The open space between the frame 10 and rods 20-23 result in better flow dynamics, which yields better process results. The open space between the frame 10 and rods 20-23 allows for complete sonic energy coverage on the reticles 50. Moreover, the minimized cross-sectional area of the rods 20-23 eliminates any shadowing of the sonic energy. Finally, minimum contact between the rods 20-23 and the reticles 50 reduces or eliminates potential for cross-contamination of tanks by reducing the amount of chemicals or residues retained at the slots 60, 61.
Finally, reticle carrier 100 facilitates consecutive processing of a plurality of reticles 50 in different chemicals and/or rinse fluids without the reticles 50 having to be removed from the carrier 100 because chemical drag is minimized. When processing reticles according to this method, the reticles 50 will be loaded into reticle carrier 100 as illustrated in
While the invention has been described and illustrated in detail herein, various modifications, improvements, and alternative embodiments should become readily apparent to those skilled in this art without departing from the spirit and scope of the invention.
The present application claims the benefit of U.S. Provisional Application 60/500,856, filed Sep. 5, 2003, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60500856 | Sep 2003 | US |