Shadow frame with sides having a varied profile for improved deposition uniformity

Embodiments of the present disclosure generally relates a shadow frame including two opposing major side frame members adjacent to two opposing minor side frame members coupled together with a corner bracket, wherein the corner bracket includes a corner inlay having legs that extend in directions generally orthogonal to each other.

BACKGROUND

Field

Embodiments of the present disclosure generally relate to a shadow frame for use in a plasma processing chamber.

Description of the Related Art

Modern semiconductor devices require the formation of features, such as OLEDs, transistors, and low-k dielectric films, by depositing and removing multiple layers of conducting, semiconducting and dielectric materials from a glass substrate. Glass substrate processing techniques include plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), etching and the like. Plasma processing is widely used in the production of flat panel devices due to the relatively lower processing temperatures required to deposit a film and good film quality which can result from using plasma processes.

In general, plasma processing involves positioning a substrate on a support member (often referred to as a susceptor or heater) disposed in a vacuum chamber and forming a plasma adjacent to the upper exposed surface of the substrate. The plasma is formed by introducing one or more process gases into the chamber and exciting the gases with an electrical field to cause dissociation of the gases into charged and neutral particles. A plasma may be produced inductively, e.g., using an inductive RF coil, and/or capacitively, e.g., using parallel plate electrodes, or by using microwave energy.

During processing, the edge and backside of the glass substrate as well as the internal chamber components must be protected from deposition. Typically, a deposition masking device, or shadow frame, is placed about the periphery of the substrate to prevent processing gases or plasma from reaching the edge and backside of the substrate and to hold the substrate on a support member during processing. The shadow frame may be positioned in the processing chamber above the support member so that when the support member is moved into a raised processing position, the shadow frame is picked up and contacts an edge portion of the substrate. As a result, the shadow frame covers several millimeters of the periphery of the upper surface of the substrate, thereby preventing backside and edge deposition on portions of the substrate covered by the shadow frame.

With consideration of the benefits of using a shadow frame, there are a number of disadvantages with current shadow frame designs. Prior art shadow frames typically reduces deposition on uncovered edges of the substrate near the edges of the shadow frame as compared to deposition inward of the edges of the substrate. This deposition non-uniformity is more exaggerated at the corners of the substrate.

Thus, there is a need in the art for a shadow frame which provides more deposition on the periphery of a substrate.

SUMMARY

Embodiments of the present disclosure generally relate a shadow frame including two opposing major side frame members adjacent to two opposing minor side frame members coupled together with a corner bracket, wherein the corner bracket includes a corner inlay having legs that extend in directions generally orthogonal to each other.

In another embodiment, a shadow frame is disclosed that includes two opposing major side frame members adjacent to two opposing minor side frame members coupled together with a corner bracket at a coupling interface, wherein each corner bracket includes a corner inlay having legs that extend in directions generally orthogonal to each other, and wherein each corner bracket includes a rounded corner.

In another embodiment, a shadow frame is disclosed that includes two opposing major side frame members adjacent to two opposing minor side frame members coupled together with a corner bracket at a coupling interface comprising a recessed area, wherein each corner bracket includes a rounded corner and a corner inlay having legs that extend in directions generally orthogonal to each other, the corner inlay includes a planar upper surface and a sloped planar surface that is angled from a plane of the planar upper surface, and a notch formed at a center of the recessed area

DETAILED DESCRIPTION

Embodiments of the present disclosure generally relate to a shadow frame for use in a processing chamber. In one or more embodiments described below, a shadow frame is formed as a multi-piece shadow frame body.

The shadow frame enhances amorphous silicon uniformity because of the narrow edge lip and thus, less shadowing of the substrate. The uniform arrangement of the electrically insulating material also assists in amorphous silicon deposition uniformity. Embodiments of the disclosure are more clearly described with reference to the figures below.

FIG. 1is a schematic cross sectional view of an exemplary processing chamber10with a shadow frame according to one embodiment. One example of the process chamber that may be adapted to benefit from the disclosure is a PECVD process chamber, available from AKT America, Inc, a subsidiary of Applied Materials, Inc., located in Santa Clara, Calif. It is contemplated that other plasma processing chambers, including those from other manufacturers, may be adapted to practice the present disclosure.

The processing chamber10comprises a chamber body12and a backing plate14disposed thereon. The chamber body12has a processing region16. The dimensions of the chamber body12and related components of the processing chamber10are not limited and generally are proportionally larger than the size of a substrate29to be processed. Any suitable substrate size may be processed. Examples of suitable substrate sizes include substrate having a surface area of about 5,500 centimeter square or more, such as about 25,000 centimeter square or more, for example about 50,000 centimeter square or more. In one embodiment, a substrate having a surface area of about 100,000 centimeter square or more may be processed.

A gas distribution plate18is mounted to the backing plate14and defines the upper boundary of the processing region16. A plurality of holes20are formed in the gas distribution plate18to allow delivery of processing gases therethrough. A gas source40can deliver a gas to the plenum formed between the gas distribution plate18and the backing plate14so as to evenly distribute the processing gas and thus, uniformly deliver the processing gas through the gas distribution plate18. A power source42is electrically coupled to the gas distribution plate18to create a plasma from the processing gas that flows through the holes20. The substrate support32is almost entirely made of aluminum or another conductive metal to function as a counter-electrode to the gas distribution plate18. The power source42can be any type of power source used in PECVD chambers, such as a RF power source. A shadow frame22is shown disposed on a substrate support32. The shadow frame22includes a shadow frame body24with a frame member26affixed thereto.

The chamber body12also includes a shadow frame support44which is formed annularly around the substrate support32. When the substrate support32is in a lowered position, the shadow frame22is supported by the shadow frame support44.

The substrate support32, also referred to as a susceptor or heater, is disposed in the processing chamber10and is actuated by a motor33. In a raised processing position, the substrate support32, having the substrate29disposed on a substrate supporting surface34thereof, supports the shadow frame body24of the shadow frame22and defines the lower boundary of the processing region16such that the substrate29is positioned in the processing region16. The frame member26both extends over and contacts a portion of the substrate29while the shadow frame body24rests on the substrate supporting surface34.

The substrate29is introduced into and removed from the processing chamber10through an opening36formed in the chamber body12which is selectively sealed by a slit valve mechanism (not shown). Lift pins38are slidably disposed through the substrate support32and can be adapted to hold a substrate at an upper end thereof. The lift pins38can be actuated by lowering the substrate support32using the motor33.

FIG. 2is an isometric view of the substrate support32ofFIG. 1and a shadow frame22according to one embodiment. The shadow frame22includes two opposing major side frame members26adjacent to two opposing minor side frame members28. Each of the major side frame members26are coupled to the minor side frame members28by corner brackets30. Additionally, the substrate support32includes corner inlays50at the interface between a substrate receiving surface52and a peripheral ledge54of the substrate support32. As mentioned above, a body56of the substrate support32is made of aluminum or other electrically conductive material in order to function as a counter-electrode in conjunction with the gas distribution plate18. However, the corner inlays50may be made of a ceramic material that is recessed within a pocket formed in the body56. The corner inlays50may reduce arcing in a case where a substrate is slightly misaligned with the substrate receiving surface52of the substrate support32.

FIG. 3is an enlarged isometric view of the substrate support32and the shadow frame22ofFIG. 2. The corner inlay50is shown in a pocket58formed in the body56of the substrate support32. The corner bracket30is also shown coupling a minor side frame member28with a major side frame member26. The corner bracket30includes a radiused or rounded corner60and a leg62that extends orthogonally from a longitudinal direction of the major side frame member26. In one aspect, the major side frame members26, which include the leg62on opposing ends thereof, have a “C” shape. The corner bracket30also includes a corner inlay64coupled to an inner peripheral edge66,68, of the major side frame member26and the minor side frame member28, respectively. The corner inlay64may be fastened to the major side frame member26using a fastener70. A seam cover72may be included to cover the interface between the major side frame member26, the corner inlay64, and the minor side frame member28. Fasteners70may be utilized to secure the seam cover72to the major side frame member26. All of the corner inlay64, the fasteners70, the major side frame member26, the minor side frame member28, and the seam cover72may be made of a ceramic material.

FIG. 4is an exploded isometric view of the corner bracket30. The major side frame member26includes a recessed area74where the corner inlay64may be placed. As a 90 degree corner may be difficult to form in the recessed area74, a radius or notch76may be provided on an inner edge of the recessed area74. Openings78are included in the recessed area74for the fasteners70shown inFIG. 3.

The corner inlay64includes a body79having a planar surface80transitioning to a tapered or sloped planar surface82. Openings78are formed in the body79for receiving the fasteners70shown inFIG. 3. The body79includes two legs81and83that extend in directions generally orthogonal to each other. The intersection of the sloped planar surface82on each leg81and83includes a radius corner84.

A coupling interface86is utilized to couple the major side frame member26to the minor side frame member28. The coupling interface86includes a plurality of pins88. The pins88are inserted into openings formed in edges of the major side frame member26and the minor side frame member28. Fasteners90may be utilized to secure the pins88in the major side frame member26and the minor side frame member28. The pins88may be a metallic material, such as aluminum. The fasteners90may be made of a ceramic material.

Each of the seam covers72include a first surface92and a recessed second surface94below a plane of the first surface92. The recessed second surface94may be angled to substantially match the angle of the sloped planar surface82of the corner inlay64.

FIG. 5is a side cross sectional view of a frame member95along lines5-5ofFIG. 4. The frame member95may be either of the major side frame member26or the minor side frame member28. An inner peripheral edge96is shown, which may be the inner peripheral edge66,68of the major side frame member26or the minor side frame member28. The inner peripheral edge96includes a planar surface97which is orthogonal to a plane of an upper surface98of the frame member95. The inner peripheral edge96may be referred to as a “bull nose” configuration.

FIG. 6is a side cross sectional view of the corner inlay64along lines6-6ofFIG. 4. The sloped planar surface82includes an angle α from a plane of the planar surface80. The angle α may be about 6 degrees to about 8 degrees, such as about 7 degrees. The sloped planar surface82may be referred to a “knife edge” configuration. A substrate coverage area99is shown inFIG. 6. The substrate coverage area99may be about 7 millimeters, about 5 millimeters, or about 3 millimeters.

Extensive testing was performed utilizing the shadow frame22as described herein. Deposition on the edge of substrates adjacent to the inner peripheral edges66,68of the major side frame member26and the minor side frame member28, and the sloped planar surface82of the corner inlay64showed an increase in thickness profile.