Phenyl-Modified Silicone for Plasma Etching Focus Rings
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Solution Overview
Problem
Conventional thermally conductive members used in semiconductor etching processes degrade in plasma environments due to radical generation and high temperatures, leading to increased thermal resistance and reduced cooling performance.
Innovation Solution
A thermally conductive silicone composition comprising a phenyl-modified organopolysiloxane, phenyl-modified organohydrogenpolysiloxane, and a hydrosilylation catalyst, with a thermally conductive filler and heat stabilizer, which maintains flexibility at low temperatures and provides plasma environmental degradation resistance, ensuring stable adhesion and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thermally conductive member is used in high-powered plasma etching, then thermal conductivity is achieved, but the member degrades due to radical generation and high temperatures, leading to increased thermal resistance
Solution Approach 1:
The patent uses a composite material consisting of phenyl-modified organopolysiloxane, phenyl-modified organohydrogenpolysiloxane, and hydrosilylation catalyst. The phenyl groups provide radical resistance against plasma degradation, while the silicone backbone maintains thermal conductivity. This composite structure resolves the contradiction by combining materials with complementary properties: plasma resistance from phenyl groups and thermal conduction from the silicone matrix.
Solution Approach 2:
The patent modifies the chemical structure of the polysiloxane by introducing phenyl groups at specific positions. This parameter change (adding phenyl substitution) transforms the material properties to simultaneously achieve plasma environmental degradation resistance and maintain thermal conductivity, preventing the increase in thermal resistance that would normally occur during plasma exposure.
2Temperature
If the mounting table temperature is lowered to cool the focus ring, then cooling performance improves, but adhesion between the mounting table and thermally conductive member decreases due to hardening
Solution Approach 1:
The patent modifies the glass transition temperature and mechanical properties of the thermally conductive member by incorporating phenyl-modified polysiloxane structures. This parameter change enables the material to maintain flexibility and adhesion strength at low temperatures where conventional materials would harden and lose bonding capability, thus resolving the contradiction between cooling performance and adhesion.
3Productivity
If high-powered plasma is used for etching, then etching depth and quality improve, but temperature rise of the focus ring increases due to heat transfer
Solution Approach 1:
The patent employs a composite thermally conductive member with phenyl-modified organopolysiloxane and organohydrogenpolysiloxane that provides enhanced thermal conductivity while maintaining plasma resistance. This composite material efficiently conducts heat away from the focus ring during high-powered plasma etching, preventing excessive temperature rise while enabling high etching quality and productivity.
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 composition achieves stable thermal conductivity and adhesion, suppressing temperature rise of the focus ring during high-powered plasma etching, enhancing semiconductor etching quality and productivity by maintaining flexibility and preventing degradation in harsh environments.
Implementation Method 1
a thermally conductive silicone composition comprising a silicone resin component and a thermally conductive filler (C), the silicone resin component comprising an organopolysiloxane (A) having alkenyl groups at least at both ends, an organohydrogenpolysiloxane (B) having at least one hydrogen atom bonded to a silicon atom in one molecule, and a hydrosilylation catalyst (D)
Implementation Method 2
arranging the thermally conductive member 5 between the mounting table 2 and the focus ring 3 to transfer heat of the focus ring 3 to the mounting table 2 through the thermally conductive member 5
Implementation Method 3
when the thermally conductive member is mounted on the mounting table in such an arrangement that part of the thermally conductive member is exposed to plasma environment that is a vacuum and high-temperature environment, radical generation due to plasma exposure advances deterioration of a silicone gel used as the thermally conductive member
Data Source
AI summary
A thermally conductive silicone composition includes a silicone resin component and a thermally conductive filler (C), the silicone resin component comprising an organopolysiloxane (A) having alkenyl groups at least at both ends, an organohydrogenpolysiloxane (B) having at least one hydrogen atom bonded to a silicon atom in one molecule, and a hydrosilylation catalyst (D). The organopolysiloxane (A) is a phenyl-modified organopolysiloxane having at least one phenyl group in a molecule. The organohydrogenpolysiloxane (B) is a phenyl-modified organohydrogenpolysiloxane having at least one phenyl group in a molecule. A blending ratio of the thermally conductive filler (C) is 200 to 1500 parts by weight based on 100 parts by weight of the silicone resin component. A hardness of a cured product of the thermally conductive silicone composition is 70 or less in terms of Asker C hardness (in accordance with JIS K6249).