Azimuthally Tunable Multi-Zone Electrostatic Chuck for Temperature Uniformity
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Solution Overview
Problem
In semiconductor manufacturing, achieving uniform temperature control across substrates using electrostatic chucks is challenging due to non-homogeneous chuck construction and conventional cooling plate designs, leading to local hot and cold spots and non-uniform processing results.
Innovation Solution
A substrate support assembly with spatially tunable heaters allows for discrete lateral and azimuthal tuning of the temperature profile, enabling the correction of critical dimension variations by compensating for chamber non-uniformities, such as temperature, flow conductance, and electrical fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling plates with edge to center temperature control are used, then the substrate support assembly can be manufactured with simple structure, but local hot and cold spots cannot be controlled resulting in non-uniform temperature distribution
Solution Approach 1:
The heating system is divided into multiple independently controllable heater zones (e.g., first through fourth heaters in different radial regions, and first through fourth azimuthal heaters in different angular positions). Each heater can be controlled separately to compensate for local temperature variations, transforming a uniform heating problem into a distributed control system that eliminates hot and cold spots while maintaining overall temperature uniformity within ±0.3°C
Solution Approach 2:
Different regions of the substrate support assembly are provided with tailored heating control. The spatially tunable heaters enable discrete lateral and azimuthal tuning of the temperature profile, allowing each local region to be optimized for its specific thermal requirements based on the deviation profile from metrology data, thereby achieving uniform temperature distribution across the entire substrate surface
2Manufacturing precision
If spatially tunable heaters are used to eliminate local hot and cold spots, then temperature uniformity can be maintained within ±0.3 degrees Celsius, but the device complexity increases due to independent control of hundreds of heaters
Solution Approach 1:
The system incorporates a feedback loop where metrology equipment measures the substrate or chuck temperature distribution, generates a deviation profile from the target temperature, and uses this information to adjust the power supplied to each spatially tunable heater. This closed-loop control automatically compensates for temperature variations and maintains critical dimension uniformity without requiring manual intervention or complex manual calibration
Solution Approach 2:
The control system dynamically adjusts the electrical power parameters (voltage, current, or PWM duty cycle) supplied to each heater based on the deviation profile. By changing these electrical parameters in response to measured temperature variations, the system achieves precise temperature control and manufacturing precision while keeping the control architecture manageable through automated parameter adjustment
3Productivity
If conventional cooling plates are used, then the system can operate with simple heat transfer schemes, but temperature profile varies from substrate to substrate during production runtime
Solution Approach 1:
The system performs preliminary temperature mapping and deviation profile determination for each substrate or chuck, then pre-adjusts the heater power distribution before processing begins. This preliminary action compensates for expected temperature variations due to substrate positioning or chamber conditions, ensuring consistent temperature profiles across multiple substrates during production runtime without requiring reconfiguration between runs
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 solution effectively eliminates local hot and cold spots, achieving precise temperature control and uniform processing results by independently controlling hundreds of spatially tunable heaters, maintaining temperature uniformity to within ±0.3 degrees Celsius.
Implementation Method 1
an electrostatic chuck having a chucking electrode, a dielectric body, and a plurality of heaters embedded within the dielectric body
Implementation Method 2
a plurality of spatially tunable heaters embedded within the dielectric body at respective discrete locations
Data Source
AI summary
Implementations described herein provide a method for processing a substrate on a substrate support assembly which enables both lateral and azimuthal tuning of the heat transfer between an electrostatic chuck and a substrate. The method includes processing a first substrate using a first temperature profile on a substrate support assembly having primary heaters and spatially tunable heaters. A deviation profile is determined from a result of processing the first substrate. The spatially tunable heaters are controlled in response to the deviation profile to enable discrete lateral and azimuthal tuning of local hot or cold spots on the substrate support assembly in forming a second temperature profile. A second substrate is then processed using the second temperature profile.