Electrostatic Sample Holder Fixing Structure for Thermal Uniformity
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Solution Overview
Problem
Existing sample holders for semiconductor wafers experience non-uniform thermal conductivity and thermal expansion issues due to the bonding of ceramic plates to metal cooling members, leading to inconsistencies in thermal uniformity and potential warping during plasma processing.
Innovation Solution
A sample holder design featuring a ceramic plate with an electrostatic adsorption surface, a base member with through holes, and a fixing mechanism that secures the ceramic plate to the base member inward of its peripheral edge, using a pillar-shaped member and fixing member to ensure close contact and reduce thermal conductivity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic plate is bonded to a metal cooling member, then the sample holder can be cooled during plasma processing, but thermal expansion differences cause non-uniform thermal conductivity and warping
Solution Approach 1:
The fixing mechanism is divided into multiple segments (first fixing member and second fixing member) that independently adjust and apply pressure to different regions of the ceramic plate, allowing localized compensation for thermal expansion differences and non-uniform thermal conductivity
Solution Approach 2:
The fixing members are designed to be adjustable and movable, enabling dynamic pressure application to the ceramic plate during assembly and operation, which compensates for thermal expansion differences between the metal cooling member and ceramic plate, thereby improving thermal uniformity and preventing warping
2Stability of the object's composition
If the ceramic plate is fixed to the cooling member, then the structure is stable, but thermal expansion differences lead to warping during plasma processing
Solution Approach 1:
The fixing members are designed to be adjustable and movable, enabling dynamic pressure application to the ceramic plate during assembly and operation, which compensates for thermal expansion differences between the metal cooling member and ceramic plate, thereby improving thermal uniformity and preventing warping
Solution Approach 2:
The fixing mechanism allows for adjustment of pressure parameters applied to the ceramic plate, enabling optimization of contact pressure to maintain structural stability while compensating for thermal expansion effects during plasma processing
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 design enhances thermal uniformity and reduces warping by minimizing thermal expansion differences between the ceramic plate and metal base, improving the overall thermal consistency and stability of the sample holder during plasma processing.
Implementation Method 1
a first surface on which a sample is to be held by electrostatic adsorption
Data Source
AI summary
The sample holder includes a ceramic plate, a base member, and a fixing mechanism. The ceramic plate includes a first surface and a second surface opposite to the first surface. The base member includes a third surface located on the second surface of the ceramic plate and facing the second surface, a fourth surface located opposite to the third surface, and a through hole located at a position more inward than a peripheral edge of the ceramic plate and passing through the third surface and the fourth surface. The fixing mechanism is located corresponding to the through hole of the base member, and fixes the base member and the ceramic plate.