KR-20260066025-A - Substrate support apparatus for cryogenic etching comprising an integrated magnetic chiller plate

Abstract

The present invention relates to a substrate support device for cryogenic etching comprising an integrated magnetic chiller plate. It comprises an integrated magnetic chiller plate in which a magnetic member and a cooling member are integrated within a single member instead of a conventional multilayer mechanical assembly structure, and an electrostatic chuck that is uniformly adhered to the surface without contact by the magnetic force of the magnetic chiller plate. According to the present invention, magnetic attraction acts uniformly across the entire surface of the member, thereby actively eliminating the physical gap between the electrostatic chuck and the magnetic chiller plate, which minimizes interfacial thermal resistance and improves the temperature uniformity of the wafer. Furthermore, by dividing and arranging the electromagnet coils into multiple independent regions, the problem of yield reduction in the outer periphery is resolved by actively compensating for the lifting phenomenon that frequently occurs in the outer periphery of the electrostatic chuck. Additionally, maintenance and replacement of the electrostatic chuck are easy because the magnetic attraction is immediately dissipated simply by cutting off the current.

Inventors

• 안범주

Assignees

• 안범주

Dates

Publication Date

20260512

Application Date

20260423

Claims (2)

1. A substrate support device for a semiconductor etching process comprising: a magnetic chiller plate having a refrigerant circulation channel formed therein and formed integrally such that the material itself is made of a magnetic material or a means for generating magnetic force is embedded therein; and an electrostatic chuck disposed on the upper portion of the magnetic chiller plate and physically adhering to the surface of the plate by receiving downward attraction from the magnetic force generated by the plate, thereby eliminating a physical gap between the plate and the electrostatic chuck and optimizing the heat conduction path in a vacuum environment.
2. A substrate support device for cryogenic etching according to claim 1, characterized in that no adhesive, bonding resin, solder, brazing material, O-ring, or mechanical fastener is interposed at the interface between the electrostatic chuck and the magnetic chiller plate, and the electrostatic chuck forms a non-bonding bonding structure that is maintained on the upper surface of the magnetic chiller plate solely by the magnetic force.

Description

Substrate support apparatus for cryogenic etching comprising an integrated magnetic chiller plate The present invention relates to a substrate support device for a semiconductor etching process, and more specifically, to a substrate support device for cryogenic etching comprising an integrated magnetic chiller plate that optimizes the heat conduction path by actively eliminating the physical gap between an electrostatic chuck and a chiller plate in a vacuum environment through magnetic attraction. As semiconductor devices become more miniaturized, the importance of high aspect ratio etching processes is increasing, and these processes require cryogenic environments ranging from -80°C to -200°C. While cryogenic etching processes have the advantage of securing a vertical etching profile by suppressing chemical reactions on the sidewalls to be etched, they simultaneously impose strict thermal management requirements to rapidly and uniformly remove the massive heat generated inside the chamber from the wafer. Conventional substrate support devices for semiconductor etching processes have generally adopted a multilayer mechanical assembly structure in which an electrostatic chuck, a base plate, and a chiller plate are stacked. The electrostatic chuck is a component that adsorbs and fixes a wafer by electrostatic force, the base plate is a component that mediates structural support and RF coupling between the electrostatic chuck and the chiller plate, and the chiller plate performs the function of absorbing heat from the wafer adsorbed by the electrostatic chuck by circulating liquid nitrogen or a low-temperature refrigerant through a refrigerant circulation channel formed inside it. In conventional multilayer laminated structures, various bonding methods have been adopted to ensure thermal bonding between components. The most common method involves chemically bonding components by interposing a bonding layer, such as indium solder, silicone resin, or acrylic resin, at the interface between them. Other known methods include mechanically compressing components with multiple bolts, applying pressure with springs, or combining low-temperature brazing with electron beam welding. However, conventional bonding methods exhibit the following inherent limitations in cryogenic environments. First, in the case of bonding layer methods, the modulus of the bonding resin increases rapidly and brittleness develops at temperatures below -60°C, leading to frequent delamination, cracking, and particle formation in the bonding layer. In the case of indium solder, its relatively low melting point of 156°C makes it difficult to be compatible with high-temperature bake-out processes, and cracking occurs because it cannot withstand stress concentration caused by differential thermal expansion at cryogenic temperatures. Second, in the case of bolt fastening methods, point pressure is concentrated in the area where the fastener is located, reducing the uniformity of compression across the entire surface, and the fastener's through hole forms RF leakage paths or gas leakage paths, impairing process stability. Third, in the case of spring-pressure methods, a reliability degradation mode occurs during cryogenic cycling in which the applied pressure decreases over time due to stress relaxation and frictional wear of the spring. Fourth, in the case of brazing or welding methods, the bond is permanent, making maintenance or replacement of the electrostatic chuck difficult, and the high-temperature treatment of the bonding process causes bending deformation of the component. The limitations of these conventional technologies cause minute gaps or thickness variations, particularly at the interface between the electrostatic chuck and the chiller plate. This forms hot and cold spots at different locations on the surface of the electrostatic chuck, thereby degrading the temperature uniformity of the wafer. This reduced temperature uniformity directly and adversely affects the etching rate and the surface uniformity of the etching profile, ultimately resulting in a decrease in semiconductor device yield. In particular, the frequent lifting of the electrostatic chuck in the outer periphery of the wafer leaves the issue of yield reduction in this region as an unresolved challenge for the global semiconductor etching equipment industry. In addition, non-magnetic aluminum or aluminum alloys have been almost exclusively adopted as materials for chiller plates in the past. This is because aluminum possesses excellent thermal conductivity and processability, while simultaneously exhibiting low eddy current losses due to the application of RF bias current. In the field of conventional technology, the adoption of magnetic materials as materials for chiller plates has been virtually avoided due to the perception that magnetic metals have significantly lower thermal conductivity and higher eddy current losses compared to aluminum. Furthermore, there have been