Electrostatic Chuck Resin Layer for Low-Temperature Heat Uniformity
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Solution Overview
Problem
The flexibility of the resin layer in electrostatic chucks decreases at low temperatures, leading to destruction and reduced heat transfer characteristics and temperature uniformity due to increased storage elastic modulus and thermal expansion stress.
Innovation Solution
The resin layer is formed with adhesives having a glass transition temperature of −70° C. or lower, maintaining flexibility and suppressing curing, and is designed with a thickness of 0.25 mm or more to relax thermal expansion stress, enhancing thermal conductivity and temperature uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a resin layer is used to bond the base plate and ceramic plate, then thermal conductivity and thermal expansion difference absorption are improved, but at low temperatures (−60°C or lower), the resin layer flexibility decreases and destruction occurs due to increased storage elastic modulus
Solution Approach 1:
The patent changes the key parameter of the adhesive's glass transition temperature to −70°C or lower. This parameter change ensures that at operating temperatures of −60°C or lower, the adhesive remains in a flexible state with low storage elastic modulus, preventing resin layer destruction while maintaining thermal conductivity and thermal expansion absorption capabilities
Solution Approach 2:
The patent uses a composite adhesive system consisting of a base polymer and a plasticizer in specific proportions (plasticizer content of 10-40 parts by weight per 100 parts of base polymer). This composite formulation creates an adhesive with suppressed crystallization and appropriately low glass transition temperature, resolving the contradiction between maintaining flexibility at low temperatures and ensuring bond strength
2Strength
If the resin layer flexibility decreases at low temperatures due to increased storage elastic modulus, then the adhesive appears cured, but this causes the resin layer to be destroyed due to insufficient stress relaxation from thermal expansion differences
Solution Approach 1:
The patent modifies the adhesive's glass transition temperature parameter to −70°C or lower through formulation adjustments (adding plasticizers). This ensures that at low operating temperatures, the adhesive maintains low storage elastic modulus and high flexibility, enabling it to relax thermal expansion stresses between the base plate and ceramic plate without destruction
Solution Approach 2:
The patent designs the adhesive with suppressed crystallization characteristics and appropriately low glass transition temperature before the low-temperature operation begins. This beforehand preparation ensures that when the electrostatic chuck operates at −60°C or lower, the resin layer is already in a flexible state capable of absorbing thermal expansion differences, preventing stress concentration and destruction
3Reliability
If the resin layer is destroyed at low temperatures, then local heat transfer characteristics between the base plate and ceramic plate are reduced, but this also reduces temperature uniformity on the adsorption surface
Solution Approach 1:
The patent changes the adhesive's glass transition temperature to −70°C or lower and suppresses its crystallization behavior. This parameter change ensures that at operating temperatures of −60°C or lower, the adhesive maintains a flexible, amorphous state with good heat transfer characteristics, preventing resin layer destruction and ensuring uniform temperature distribution across the adsorption surface
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 effectively prevents resin layer destruction and maintains high temperature uniformity and thermal conductivity even at low temperatures, ensuring stable operation of the electrostatic chuck.
Implementation Method 1
at least one of the one or more adhesives has a temperature of −70° C. or lower corresponding to an extreme value of a loss tangent in a temperature range of −150° C. to 250° C.
Implementation Method 2
the stress resulting from a difference in thermal expansion between the base plate and the ceramic plate is not sufficiently relaxed by the resin layer
Implementation Method 3
The destruction of the resin layer locally reduces a heat transfer characteristic between the base plate and the ceramic plate via the resin layer
Implementation Method 4
The electrostatic chuck is configured to adsorb the wafer to the ceramic plate by using an electrostatic force when a voltage is applied to the electrode embedded in the ceramic plate
Data Source
AI summary
An electrostatic chuck includes a base plate, a ceramic plate fixed to the base plate and including an electrode embedded in the ceramic plate, and a resin layer bonding the base plate and the ceramic plate and including one or more adhesives. In at least one of the one or more adhesives, a temperature corresponding to an extreme value of a loss tangent in a temperature range of −150° C. to 250° C. is −70° C. or lower.