Bevel edge plasma chamber with top and bottom edge electrodes

#The present invention relates in general to substrate manufacturing technologies and in particular to apparatus and methods for the removal etch byproducts from a bevel edge of a substrate.

#In the processing of a substrate, e.g., a semiconductor substrate (or wafer) or a glass panel such as one used in flat panel display manufacturing, plasma is often employed. During substrate processing, the substrate (or wafer) is divided into a plurality of dies of square or rectangular shapes. Each of the plurality of dies will become an integrated circuit. The substrate is then processed in a series of steps in which materials are selectively removed (or etched) and deposited. Control of the transistor gate critical dimension (CD) on the order of a few nanometers is a top priority, as each nanometer deviation from the target gate length may translate directly into the operational speed and/or operability of these devices.

#Typically, a substrate is coated with a thin film of hardened emulsion (such as a photoresist mask) prior to etching. Areas of the hardened emulsion are then selectively removed, causing parts of the underlying layer to become exposed. The substrate is then placed on a substrate support structure in a plasma processing chamber. An appropriate set of plasma gases is then introduced into the chamber and a plasma is generated to etch exposed areas of the substrate.

#The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, and like reference numerals designate like structural elements.

#FIG. 1A shows a schematic diagram of a substrate etching system with a pair of top and bottom edge electrodes, in accordance with one embodiment of the present invention.

#FIG. 1A-1 shows another embodiment replacing resistor 152, in accordance with an embodiment of the present invention.

#Several exemplary embodiments for improved structures and mechanisms to remove etch byproducts, dielectric films and metal films near the substrate bevel edge, and chamber interior to avoid polymer byproduct and film accumulation and to improve process yield. It will be apparent to those skilled in the art that the present invention may be practiced without some or all of the specific details set forth herein.

#FIG. 1A shows a chamber 100 for cleaning a bevel edge, in accordance with one embodiment of the present invention. Chamber 100 has a substrate support 140 with a substrate 150 on top. The substrate support 140 is an electrode, which is powered by a RF (radio frequency) power source 123. The substrate support can also be called lower electrode 140. In another embodiment, the substrate support 140 is an electrostatic chuck. Opposing the lower electrode 140 is an insulator plate 163. In one embodiment, there is a gas feed 161 coupled to the center of the insulator plate 163 to provide process gas. The substrate support can also be RF powered or grounded. The substrate 150 has a bevel edge 117 that includes a top and a bottom surface of the edge of the substrate, as shown in region B of FIG. 1A and enlarged region B in FIG. 1B. In FIG. 1B, bevel edge 117 is highlighted as a bold solid line and curve.

#Surrounding the edge of lower electrode 140, there is a bottom edge electrode 120, made of conductive materials, such as aluminum (Al), anodized aluminum, silicon (Si), and silicon carbide (SiC). If the material is aluminum or anodized aluminum, the aluminum can be coated with a layer of yttrium oxide (Y2O3) to protect aluminum from being corroded by the etching chemistry. Corroded aluminum can flake off and cause particle problems. Between the lower electrode 140 and the bottom edge electrode 120, there is a bottom dielectric ring 121 electrically separating the lower electrode 140 and the bottom edge electrode 120. In one embodiment, substrate 150 is not in contact with the bottom edge electrode 120. Beyond the bottom edge electrode 120, there is another bottom insulating ring 125, which extends the surface of the bottom edge electrode 120 facing substrate 150. The bottom dielectric ring 121 and the bottom insulating ring 125 can be made of insulating materials, such as ceramic or alumina (Al2O3). The bottom edge electrode 120 is electrically and physically coupled to a lower focus ring 124.