Plasma Heater Zone Segmentation for Temperature Uniformity
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Solution Overview
Problem
Existing plasma processing apparatuses with heater zones experience temperature distribution unevenness, leading to non-uniform etching rates and shapes, particularly at the boundary between center and edge zones, resulting in degraded etching characteristics.
Innovation Solution
The apparatus divides the heater into multiple zones, allowing for separate temperature control of each zone, with correction for temperature interference from adjacent zones, and uses a control device to adjust and optimize the heater temperatures based on sensor data to achieve uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is divided into two zones (center and edge), then temperature control is improved for each zone, but temperature distribution unevenness remains within each zone, degrading etching uniformity
Solution Approach 1:
The heater is divided into multiple zones (center zone, first intermediate zone, second intermediate zone, and edge zone) instead of the conventional two zones. This further segmentation allows for more precise temperature control in each sub-zone, eliminating temperature distribution unevenness that persisted in the two-zone configuration and improving overall etching uniformity.
Solution Approach 2:
Different temperature control strategies are applied to different heater zones based on their specific thermal characteristics and etching requirements. Each zone can be independently controlled to achieve optimal local temperature, which directly improves etching uniformity across the entire wafer surface.
2Device complexity
If the heater area in each zone is large, then the heater structure is simpler, but temperature distribution unevenness is created within the same zone
Solution Approach 1:
The heater is segmented into multiple smaller zones with progressively smaller areas from center to edge. This segmentation creates a gradient structure where each zone has appropriate heating capacity for its location, achieving uniform temperature distribution while maintaining reasonable structural complexity.
Solution Approach 2:
The heater zones are designed with asymmetric area distribution, where the center zone has the largest area and the edge zone has the smallest area. This asymmetric design compensates for the different thermal requirements at different radial positions, achieving uniform temperature control across the wafer.
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
This approach ensures in-plane uniformity of the wafer temperature, reducing CD deviations and improving etching uniformity across the wafer surface by precise temperature control.
Implementation Method 1
an electrostatic chuck that is arranged on the mounting table and is configured to electrostatically attract the workpiece by applying a voltage to a chuck electrode
Implementation Method 2
a heater that is arranged within or near the electrostatic chuck and is divided into a plurality of heater zones
Data Source
AI summary
A method is provided for controlling a temperature of a heater arranged in a plasma processing apparatus that converts a gas into plasma using a high frequency power and performs a plasma process on a workpiece with the plasma. The plasma processing apparatus includes a processing chamber that can be depressurized, a mounting table that is arranged within the processing chamber, an electrostatic chuck that is arranged on the mounting table and electrostatically attracts the workpiece, and a heater that is arranged within or near the electrostatic chuck and is divided into a plurality of heater zones. The method includes adjusting a control temperature of the heater with respect to each of the heater zones, and correcting a temperature interference from an adjacent heater zone of each of the heater zones with respect to a setting temperature of each of the heater zones upon adjusting the control temperature.