Sample Table Adsorption Plate Recessed Center Design
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Solution Overview
Problem
Conventional sample tables in semiconductor manufacturing apparatuses face issues with unstable substrate holding due to curved center portions after lapping processes, leading to non-uniform temperature distribution and local hotspots, making precise temperature control difficult.
Innovation Solution
A sample table with an adsorption plate having a recessed contact surface adhered to a supporting substrate with a trapezoidal recess shape, ensuring stable substrate holding and uniform plasma processing even after surface processes like lapping, using a ceramic adsorption plate with a heater and electrostatic electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lapping process is performed to smooth the contact surface of the adsorption plate, then the heat resistance between the contact surface and the substrate is improved, but the contact surface becomes curved with a convex center portion, causing unstable substrate holding and non-uniform temperature distribution
Solution Approach 1:
Instead of making the contact surface convex (as in conventional lapping), the patent inverts the approach by making the contact surface concave with a recessed center portion. This recessed shape counteracts the thermal expansion and heat-induced curvature, maintaining stable substrate contact and uniform temperature distribution across the substrate surface.
Solution Approach 2:
The patent applies different surface characteristics to different regions of the contact surface. The center portion has a recessed shape with specific depth (0.1-10 μm) to address local thermal effects, while the peripheral portion maintains different properties. This localized quality adjustment ensures uniform heat resistance and stable substrate holding across the entire surface.
2Temperature
If the contact surface is made convex at the center to improve heat resistance, then local heat resistance is improved, but the substrate becomes tilted and develops local high temperature portions
Solution Approach 1:
The patent inverts the conventional convex center design by implementing a concave recessed center portion. This inverted geometry compensates for thermal expansion effects during plasma processing, preventing substrate tilt and ensuring uniform temperature distribution across the substrate, thereby achieving both improved heat resistance and temperature uniformity.
Solution Approach 2:
The patent changes the geometric parameter of the contact surface from convex to concave, specifically creating a recessed center portion with controlled depth (0.1-10 μm). This parameter change fundamentally alters the thermal and mechanical interaction between the adsorption plate and substrate, achieving uniform temperature distribution while maintaining good heat resistance.
3Temperature
If a recess portion is formed on the substrate holding surface to create space between the substrate and holding surface, then temperature distribution is improved, but the contact surface curvature problems persist after lapping
Solution Approach 1:
The patent applies a localized recessed structure specifically at the center portion of the contact surface with precisely controlled depth (0.1-10 μm). This local quality modification creates the necessary space for uniform temperature distribution while the recessed geometry inherently resists curvature changes during subsequent lapping processes, maintaining shape stability.
Solution Approach 2:
The recessed center portion is formed in advance during adsorption plate manufacturing, before the substrate is mounted and before any lapping processes occur. This preliminary action pre-establishes the correct geometric configuration that will maintain stability throughout subsequent processing steps, preventing contact surface curvature problems from developing.
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 stabilizes substrate holding and achieves uniform temperature distribution, reducing temperature differences to about 5°C, enabling precise control and uniform plasma processing.
Implementation Method 1
The sample table includes an adsorption plate formed of ceramic, which electrostatically holds the semiconductor wafer
Implementation Method 2
a heater for heating, etc. are buried in the adsorption plate
Implementation Method 3
a microwave plasma processing apparatus that generates plasma in a processing chamber by using microwaves to perform a plasma process on a substrate by using the plasma
Data Source
AI summary
A manufacturing method of sample table is provided. The sample table holds a semiconductor wafer on which a plasma process is to be performed, and the manufacturing method includes: preparing an adsorption plate that has a contact surface on which a lapping process has been performed and surface-contacting the semiconductor wafer, and that adsorbs the semiconductor wafer; and preparing a supporting substrate which has a recess surface to which a noncontact surface of the adsorption plate is adhered, wherein a difference between a depth of an approximate center portion of the recess surface and a depth of a distant portion spaced apart from the approximate center portion is larger than a difference between a thickness of the adsorption plate at a portion contacting the approximate center portion and a thickness of the adsorption plate at a portion contacting the distant portion.