Multi-plane heater for semiconductor substrate temperature uniformity
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Solution Overview
Problem
Achieving uniform temperature control across semiconductor substrates during plasma processing is challenging due to dynamic heat transfer processes and non-equilibrium phenomena like plasma, leading to non-uniform critical dimension (CD) and processing rate issues.
Innovation Solution
A multi-plane heater system with independently controllable resistance heating elements, arranged in series and parallel configurations, is integrated into the substrate support assembly to create a spatial temperature profile, allowing for precise thermal control and compensation for adverse factors affecting CD uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a small number of heating or cooling elements are used in the electrostatic chuck assembly, then the device complexity is reduced, but the temperature uniformity across the substrate deteriorates
Solution Approach 1:
The heating system is divided into multiple independently controllable heating zones arranged in a grid pattern across the substrate surface. Each zone can be individually controlled to compensate for local heat loss variations, achieving uniform temperature distribution without requiring a single complex heating element
Solution Approach 2:
Different regions of the substrate receive customized heating or cooling based on their specific thermal requirements. The system adjusts the power supplied to each heating zone independently, allowing local optimization of temperature control rather than applying uniform heating across the entire substrate
2Temperature
If multiple independently controlled heating elements are added to achieve uniform temperature control, then the temperature uniformity is improved, but the device complexity increases
Solution Approach 1:
Multiple heating elements are integrated into a single electrostatic chuck assembly structure, sharing common support infrastructure, electrical connections, and control electronics. This merging approach reduces overall system complexity compared to having separate temperature control systems for each heating element
Solution Approach 2:
The heating elements serve multiple functions: they provide thermal control, act as electrical contacts for the electrostatic chuck, and can be individually addressed for precise temperature profiling. This multi-functionality reduces the need for separate components and simplifies the overall system architecture
3Device complexity
If the substrate temperature profile is allowed to be non-uniform, then the device complexity is reduced, but the critical dimension uniformity deteriorates
Solution Approach 1:
The system incorporates temperature sensors that continuously monitor the actual temperature at multiple locations on the substrate. This feedback information is used by the control system to dynamically adjust the power supplied to each heating zone, compensating for deviations from the desired temperature profile and ensuring uniform critical dimensions
Solution Approach 2:
The temperature control system transitions from a static, uniform heating approach to a dynamic, adaptive system that continuously adjusts the power distribution to heating zones based on real-time temperature measurements and process requirements, enabling precise control of critical dimensions
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 system effectively maintains a uniform temperature profile, enhancing CD uniformity and processing consistency across the substrate, thereby improving semiconductor manufacturing yields.
Implementation Method 1
a first resistance heating element vertically offset from a second resistance heating element electrically connected in series to the first heating element
Implementation Method 2
an electrostatic clamping layer including at least one electrostatic clamping electrode configured to electrostatically clamp a semiconductor substrate on a support surface
Data Source
AI summary
A semiconductor substrate support for supporting a semiconductor substrate in a plasma processing chamber includes a multi-plane heater such as a heater array comprising thermal control elements operable to tune a spatial temperature profile on the semiconductor substrate. The multi-plane heater includes at least one pair of vertically offset heating elements connected in series or parallel to control heating output in a heating zone on the substrate support. The thermal control elements can be powered by two or more power supply lines and two or more power return lines wherein each power supply line is connected to at least two of the heater zones and each power return line is connected to at least two of the heater zones.