The present invention relates to wet processing techniques for substrates. More particularly, this invention relates to wet processing systems and methods utilizing a rotating splash shield.
One type tool, or system, commonly used in the processing of substrates (e.g., semiconductor substrates) is spin rinse and dry (SRD) modules. SRD modules typically dispense processing fluids (e.g., cleaning solutions, rinsing solutions, deionized water, etc.) onto the substrate and remove the processing fluids and dry the substrate via spinning. A problem often associated these systems is the splashing of the processing fluids off various portions of the system, back onto the substrate, causing contamination of the substrate.
During the rotation of the substrate, there are two major forces acting on the processing liquid as it spun off the substrate: a centrifugal force and a tangential force. The centrifugal force pulls the liquid toward the edge of substrate, and the tangential force is at tangent angle to the edge of substrate. Both of these forces are dependent on the speed, or rate, of the rotation of the substrate. Generally, the higher the speed of rotation, the more likely it is that at least some of the liquid will splash back onto the substrate due to the increased kinetic energy of the liquid as it is spun off the substrate.
Additionally, some of the liquid may be splashed onto the ceiling of the module. Although the liquid on the ceiling may not initially be a problem, over time, the liquid may accumulate and/or deposit material on the ceiling. The liquid and/or material may eventually fall onto the substrate being process, which causes further contamination.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The drawings are not to scale and the relative dimensions of various elements in the drawings are depicted schematically and not necessarily to scale.
The techniques of the present invention can readily be understood by considering the following detailed description in conjunction with the accompanying drawings, in which:
A detailed description of one or more embodiments is provided below along with accompanying figures. The detailed description is provided in connection with such embodiments, but is not limited to any particular example. The scope is limited only by the claims, and numerous alternatives, modifications, and equivalents are encompassed. Numerous specific details are set forth in the following description in order to provide a thorough understanding. These details are provided for the purpose of example and the described techniques may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the embodiments has not been described in detail to avoid unnecessarily obscuring the description.
The term “horizontal” as used herein will be understood to be defined as a plane parallel to the plane or surface of the substrate, regardless of the orientation of the substrate. The term “vertical” will refer to a direction perpendicular to the horizontal as previously defined. Terms such as “above”, “below”, “bottom”, “top”, “side” (e.g. sidewall), “higher”, “lower”, “upper”, “over”, and “under”, are defined with respect to the horizontal plane. The term “on” means there is direct contact between the elements. The term “above” will allow for intervening elements.
Embodiments described herein provide substrate processing systems and methods related to, for example, dispensing processing fluids, such as cleaning and/or rinsing solutions, onto substrates and removing the fluids/drying the substrates via spinning (e.g., spin rinse and dry (SRD) systems).
In some embodiments, splashing and/or contamination caused by splashing may be reduced by utilizing a splash shield that rotates with the substrate. The use of a splash shield that rotates with the substrate may eliminate the tangential component of the force applied to the liquid as it is spun off the substrate. Thus, when the liquid hits the rotating splash shield, less splash back may occur because the liquid impacts the splash shield with less kinetic energy than would be the case of the splash shield was not rotating (i.e., because both the substrate and the splash shield are rotating at the same rotational speed, reducing the relative velocity to of the liquid to near zero).
The upper edge of the splash shield may extend above the upper surface of the substrate and have a profile that extends towards the center of the substrate. This portion of the splash shield may be at a small angle (e.g., 1-30 degrees) to the upper surface of the substrate to further reduce the likelihood that any liquid will splash back onto the substrate (e.g., because the liquid being spun off will contact this surface at a small angle, as opposed to 90 degrees). The bottom edge of the splash shield may extend below the bottom surface of the substrate to reduce the likelihood that any liquid flowing off the splash shield will contact the substrate. The bottom edge of the splash shield may have profiled surface that is at an angle of, for example, between 1 and 90 degrees to guide the liquid flow that is spinning off the splash shield.
In some embodiments, the splash shield rests on the substrate support (or chuck) in such a way that when the substrate support is rotated, the splash shield also rotates (e.g., the splash shield has grooves that mate with portions of the substrate support). In such embodiments, the splash shield may be simply lifted off the substrate support to remove it (e.g., to transport the substrate to/from the chamber). Further, the splash shield may have pins (or other members) that extend toward the walls of the chamber, or more particularly, the lid. In turn, the lid may have a corresponding structure (e.g., a ring) that may be used to lift the splash shield off the substrate support (e.g., when the lid is removed). However, it should be noted that in some embodiments, the splash shield may be permanently connected to (e.g., integral with) the substrate support.
Although not specifically shown, in some embodiments the system 100 (and/or the base 102 and the lid 104) is substantially circular in shape (i.e., when viewed from the top or bottom). Also, in some embodiments, the base 102 includes one or more outlets for draining processing fluids.
Within the processing chamber 106, a substrate support (or substrate support assembly) 108, a splash shield 110, and a nozzle 112 are provided. In some embodiments, the substrate support 108 is configured to support a substrate 118 and includes a chuck 114 and a support shaft 116.
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In some embodiments, the chuck 114 and the splash shield 110 are made of a plastic or polymer, such as polytetrafluoroethylene (PTFE). However, other chemically inert materials, such as ceramics and some metals, may be used depending on the processing liquids utilized.
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In some embodiments, the splash shield 110 is shaped such that the inner surface 136 of the splash shield 110 at the upper portion 132 (and/or end) thereof is at an angle 148 to the upper surface 144 of the substrate 118. In other words, as the upper portion 132 of the splash shield 110 extends towards the central portion of the substrate 118, the height of the inner surface 136 of the splash shield 110 above the upper surface 144 of the substrate 118 increases. In some embodiments, the angle 148 is between about 1 degree and about 30 degrees, preferably between about 5 degrees and about 15 degrees. In some embodiments, the upper portion 132 of the splash shield 110 does not extend to a position directly above the substrate 118 (i.e., there is a gap between the lateral position of the upper end of the splash shield 110 and the outer edge of the substrate 118).
In some embodiments, the lower end 134 of the splash shield 110 is profiled as shown such that the bottom surface thereof is at an angle 149 to the upper surface 144 of the substrate 118. In some embodiments, the angle 149 is between about 1 degree and about 90 degrees, such as between about 20 degrees and about 60 degrees.
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Although not specifically shown, the nozzle 112 may be in fluid communication with one or more processing fluid sources configured to provide processing fluids, such as liquids (e.g., cleaning solutions, rinsing solutions, deionized water, etc.), to the nozzle 112. Further, the system 100 may include a control sub-system (or controller) having, for example, a processor and a memory, which is in operable communication with the other components shown in
With the substrate placed on the chuck 114 and the splash shield 110 positioned on the shield supports 124, a processing liquid may be dispensed from the nozzle 112 onto the substrate 118. After at least some of the processing liquid is dispensed onto the substrate 118, the chuck 114, and thus the substrate 118, may be rotated by the drive mechanism 130 (e.g., about the axis 131). In some embodiments, the rotation of the chuck 114 causes rotation of the splash shield 110 (e.g., about the axis 131).
The rotation of the chuck 114, and the splash shield 110, may occur while the processing liquid is being dispensed. In some embodiments, the rotation of the chuck 114 and/or the substrate 118 continues after the cessation of the dispensing of the processing liquid. That is, the rotation of the chuck 114/substrate 118 may continue for some time, such as between about 10 seconds and about 5 minutes, after the dispensing of the processing liquid has been ceased. In some embodiments, the substrate 118 is rotated at any rate between 0 revolutions per minute (rpm) and about 2500 rpm, such as about 1200 rpm, for any duration (e.g., between about 5 seconds and about 5 minutes).
Thus, in some embodiments, rotation of the splash shield 110 is caused by the rotation of the chuck 114, which is driven by the drive mechanism 130. However, in other embodiments, a separate actuator may be provided for the splash shield 110 so that the splash shield 110 may be rotated in a manner independent of (e.g., in a different direction and/or at a different speed/rate than) the chuck 114 and/or the substrate 118.
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Additionally, due to the size and shape of the splash shield 110, particularly the profile of the inner surface 136 of the splash shield 110, the odds of any splash back/contamination are further reduced. Specifically, because the upper portion 132 of the splash shield 110 extends inwards, towards the center portion of the substrate 118, and/or the angle 148 between the inner surface 136 of the splash shield 110 at the upper portion 132 of the splash shield 110 and the upper surface 144 of the substrate 110, processing liquid that impacts the inner surface 136 of the splash shield 110 at the upper portion 132 thereof is gradually deflected by and flows down the inner surface 136, as opposed to splashing off the splash shield 110 (i.e., and perhaps back onto the substrate 118). Such a flow of the processing liquid is indicated by the arrows in
This effect may be enhanced by minimizing the lateral spacing between the inner surface 136 of the splash shield 110 and the substrate 118. That is, in some embodiments, the lateral spacing between the splash shield 110 and the substrate 118 combined with the rate at which the substrate 118 is rotated is such that the processing liquid impacts the splash shield 110 before the stream of flow of the processing liquid off the upper surface 144 of the substrate 118 is broken (i.e., a substantially constant stream of processing liquid flows off the substrate 118 into the splash shield 110, as opposed to the processing liquid breaking apart into individual portions/drops).
Additionally, shape, profile, and position of the splash shield, particularly the inner surface 136 on the upper portion 132, may prevent any of the processing from splashing upwards onto the ceiling of the processing chamber 106 (i.e., the top portion of the lid 104), which may otherwise lead to additional contamination. Furthermore, because the lower portion 134 (or end) of the splash shield 110 is at a height below that of the lower surface 146 of the substrate 110, processing liquid flowing off the lower portion 134 of the splash shield 110 is unlikely to impact the lower surface 146 of the substrate 118. The angle 149 at the bottom end 134 of the splash shield 110 may further assist in guiding the liquid flowing off the splash shield 110 away from the lower surface 146 of the substrate 118.
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After the lid 104 and the splash shield 110 are removed, the substrate 118 may be lifted off the chuck 114 and replaced by a subsequent substrate to be processed in a manner similar that described above. When the lid 104 is placed back onto the base 102, the splash shield 110 may also be positioned back onto, and aligned with, the chuck 114 in the manner described above.
However, it should be noted that in some embodiments, the splash shield 110 may be permanently connected to the chuck 114 such that it can not be lifted off the chuck 114. For example, the splash shield 110 may be formed as an integral piece of the chuck 114 (e.g., the splash shield and the chuck 114 may be made from a single piece of material). In such embodiments, the splash shield 110 may be appropriately sized and shaped so that the substrate 118 may be placed onto and removed from the chuck 114 through the opening in the splash shield 110.
At block 1204, a splash shield is positioned at least one side of the substrate. In some embodiments, the splash shield extends around a periphery of the substrate. The splash shield may have an upper portion that extends to a height greater than (i.e., above) an upper surface of the substrate and a lower portion that extends to a height less than (i.e., below) a lower surface of the substrate. The splash shield may be shaped such that the upper portion thereof extends towards a central portion of the substrate. In some embodiments, an inner surface of the splash shield at the upper portion thereof is at an angle to the upper surface of the substrate. The angle may be between about 5 degrees and about 30 degrees (e.g., between about 5 degrees and about 15 degrees).
In some embodiments, the splash shield is supported by a substrate support on which the substrate is placed. The splash shield may mate with the substrate support such that when the substrate support (and/or the substrate) is rotated, the splash shield also rotates. In some embodiments, the splash shield may be lifted off of the substrate support.
At block 1206, a processing liquid (e.g., a cleaning or rinsing solution) is dispensed onto the substrate (e.g., the upper surface of the substrate). At block 1208, the substrate is rotated after at least some of the processing liquid is dispensed onto the substrate. The rotation of the substrate may occur while the processing liquid is being dispensed onto the substrate. In some embodiments, the rotation of the substrate continues after the cessation of the dispensing of the processing liquid. In some embodiments, the substrate is rotated at between about 0 rpm and about 2500 rpm, such as about 1200 rpm. In some embodiments, the substrate is rotated about a central portion (e.g., axis) thereof.
At block 1210, the splash shield is rotated while the substrate is rotated. In some embodiments, the splash shield is rotated in the same direction and at the same rate as the substrate. The rotation of the splash shield may (also) occur while the processing liquid is being dispensed onto the substrate.
Thus, in some embodiments, substrate processing systems are provided. The processing systems include a fluid dispenser configured to dispense a processing fluid. A substrate support configured to support and rotate a substrate is also included. The substrate support is disposed such that the processing fluid dispensed by the fluid dispenser flows onto the substrate. A splash shield is positioned on at least one side of the substrate support and configured to rotate with the substrate. The splash shield has an upper portion extending above an upper surface of the substrate and a lower portion extending below a lower surface of the substrate.
In some embodiments, substrate processing systems are provided. The processing systems include a fluid dispenser configured to dispense a processing fluid. A substrate support configured to support and rotate a substrate about an axis is also included. The substrate support is disposed below the fluid dispenser such that the processing fluid dispensed by the fluid dispenser flows onto the substrate. A splash shield is arranged about a periphery of the substrate. The splash shield has an upper portion extending above an upper surface of the substrate and a lower portion extending below a lower surface of the substrate. The splash shield is coupled to the substrate support such that the rotation of the substrate about the axis causes rotation of the splash shield about the axis and causes the processing fluid dispensed onto the substrate to flow towards the splash shield.
In some embodiments, methods for processing a substrate are provided. A substrate having an upper surface and a lower surface is provided. A splash shield is positioned on at least one side of the substrate. The splash shield has an upper portion extending above the upper surface of the substrate and a lower portion extending below the lower surface of the substrate. A processing liquid is dispended onto the upper surface of the substrate. The substrate is rotated after at least some of the processing liquid is dispensed onto the upper surface of the substrate. During the rotating of the substrate, the splash shield is rotated.
Although the foregoing examples have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed examples are illustrative and not restrictive.