Electrostatic Chuck Insulating Film for Voltage and Temperature
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Solution Overview
Problem
Existing electrostatic chucks with ceramic porous bodies in the gas feed channel face challenges in achieving high insulation breakdown voltage and maintaining wafer temperature uniformity, leading to issues like hot spots and cold spots during substrate processing.
Innovation Solution
Incorporating a ceramic insulating film denser than the porous body within the gas feed channel, which bites into the porous body, enhances insulation breakdown voltage and ensures uniform temperature distribution by preventing peeling and sealing of the film, thus maintaining stable cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic porous body is provided in the gas feed channel to improve insulation performance, then insulation breakdown voltage is enhanced, but heat transfer coefficient decreases causing temperature non-uniformity
Solution Approach 1:
The patent applies local quality by providing the ceramic insulating film only at specific locations where discharge is likely to occur (at the inlet and outlet of the gas feed channel), rather than making the entire gas feed channel structure dense. This localized approach enhances insulation where needed while maintaining the porous structure's heat transfer performance in other regions.
Solution Approach 2:
The patent uses composite materials by combining the ceramic porous body (for heat transfer) with the ceramic insulating film (for discharge prevention). This composite structure allows the system to simultaneously achieve both high heat transfer coefficient and high insulation breakdown voltage, resolving the contradiction between thermal performance and electrical insulation.
2Reliability
If a ceramic porous body is used in the gas feed channel, then discharge is prevented, but heat transfer from the base plate to the ceramic dielectric substrate decreases
Solution Approach 1:
The ceramic insulating film is applied locally only at the inlet and outlet portions of the gas feed channel where electrical discharge is most likely to occur. The majority of the gas feed channel structure remains as ceramic porous body, preserving its high heat transfer coefficient and minimizing energy loss while still achieving discharge prevention at critical locations.
Solution Approach 2:
The ceramic insulating film acts as an intermediary element that provides electrical insulation without significantly impeding thermal transfer. By positioning it strategically at channel entrances and exits, it prevents discharge while allowing the underlying porous structure to maintain efficient heat transfer from the base plate.
3Ease of manufacture
If the ceramic insulating film is not densely bonded to the porous body, then manufacturing is easier, but peeling and sealing occur reducing insulation performance
Solution Approach 1:
The patent applies preliminary action by forming the ceramic insulating film so that it protrudes into the ceramic porous body before final assembly. This protrusion creates mechanical interlocking that prevents peeling during operation, ensuring long-term reliability without requiring complex bonding processes. The film is prepared in advance with this geometric feature that self-secures it to the porous body.
Solution Approach 2:
The patent solves the bonding problem by transitioning from a two-dimensional surface bonding approach to a three-dimensional interlocking approach. The ceramic insulating film protrudes into the porous body, creating anchoring points throughout the volume rather than relying solely on surface adhesion. This dimensional change ensures robust mechanical bonding while maintaining manufacturing simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly increases insulation breakdown voltage and achieves high wafer temperature uniformity by preventing hot spots and cold spots, ensuring reliable and efficient substrate processing.
Implementation Method 1
an insulator plug including a ceramic porous body provided in the gas feed channel and a ceramic insulating film provided between the ceramic porous body and the gas feed channel
Implementation Method 2
a ceramic porous body provided in the gas feed channel
Implementation Method 3
an inert gas such as He is passed between the front surface of the ceramic dielectric substrate and the back surface of the clamped target substrate to control the temperature of the clamped target substrate
Implementation Method 4
An electrostatic clamping force is applied to the incorporated electrode. Thus, the electrostatic chuck clamps a substrate such as a silicon wafer by electrostatic force
Data Source
AI summary
According to an aspect of an embodiment of the invention, there is provided an electrostatic chuck including: a ceramic dielectric substrate including a first major surface for mounting a clamped target, a second major surface on opposite side from the first major surface, and a through hole provided from the second major surface to the first major surface; a metallic base plate supporting the ceramic dielectric substrate and including a gas feed channel communicating with the through hole; and an insulator plug including a ceramic porous body provided in the gas feed channel and a ceramic insulating film provided between the ceramic porous body and the gas feed channel and being denser than the ceramic porous body, the ceramic insulating film biting into the ceramic porous body from a surface of the ceramic porous body.