Substrate Processing Temperature Correction for Resist Pattern Uniformity
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Solution Overview
Problem
In photolithography processing, heaters embedded in thermal plates can lead to non-uniform heating, resulting in resist patterns that are not formed in predetermined dimensions across a semiconductor wafer, due to fixed heater patterns that cannot be corrected to a uniform temperature.
Innovation Solution
A substrate processing method that involves measuring the dimensions of resist patterns, correcting thermal processing temperatures, classifying dimension distributions into linear and nonlinear components, and adjusting exposure conditions for each region based on the linear component to ensure uniform resist pattern formation across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heaters are fixed to a thermal plate in a predetermined pattern, then the thermal plate can be adjusted to a predetermined temperature by adjusting the heater temperature, but there might be a region where the thermal plate could not be corrected to a predetermined temperature, resulting in non-uniform heating
Solution Approach 1:
The thermal plate is divided into multiple heating regions, each with an independently controllable heater. This segmentation allows different regions to be heated to different temperatures, enabling correction of non-uniform temperature distribution across the plate while maintaining overall temperature control.
Solution Approach 2:
Different regions of the thermal plate are assigned different heating characteristics based on their specific thermal requirements. By making the heater temperature adjustable for each region, the system achieves local temperature optimization, ensuring that each area reaches the predetermined temperature uniformly.
2Manufacturing precision
If the heating temperature of PEB processing is corrected based on dimension measurement, then the dimension of the resist pattern can be made appropriate, but the correction cannot be applied uniformly across all regions due to fixed heater patterns
Solution Approach 1:
The heater temperature settings are made dynamic and adjustable for each heating region based on measured dimension data. This allows the system to adapt the temperature correction to the specific needs of each region, transforming a static, uniform heating approach into a dynamic, region-specific correction strategy.
Solution Approach 2:
The system measures the dimension of resist patterns and uses this feedback information to adjust the heater temperature for each region. This closed-loop control enables continuous optimization of temperature distribution to achieve uniform resist pattern dimensions across the entire thermal plate.
3Ease of operation
If a single heater temperature is applied to the entire thermal plate, then the system is simple to operate, but regions with different thermal characteristics cannot be corrected to predetermined temperature
Solution Approach 1:
The thermal plate is divided into multiple heating regions, each with an independently controllable heater. This segmentation allows different regions to be heated to different temperatures, enabling correction of non-uniform temperature distribution across the plate while maintaining overall temperature control.
Solution Approach 2:
Different regions of the thermal plate are assigned different heating characteristics based on their specific thermal requirements. By making the heater temperature adjustable for each region, the system achieves local temperature optimization, ensuring that each area reaches the predetermined temperature uniformly.
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 method allows for the formation of resist patterns in predetermined dimensions by correcting thermal processing temperatures and exposure conditions, ensuring uniformity and reproducibility even in non-uniform regions, thereby improving the accuracy of resist pattern formation on semiconductor wafers.
Implementation Method 1
a heater generating heat by power feeding is embedded in the thermal plate, so that the thermal plate is adjusted to a predetermined temperature by adjusting the temperature of the heater
Implementation Method 2
the thermal plate is adjusted to a predetermined temperature by adjusting the temperature of the heater
Data Source
AI summary
A processing temperature of thermal processing is corrected based on measurement of a first dimension of a resist pattern on a substrate from a previously obtained relation between a dimension of a resist pattern and a temperature of thermal processing, a second dimension of the resist pattern after thermal processing is performed at the corrected processing temperature is measured, a distribution within the substrate of the second dimension is classified into a linear component expressed by an approximated curved surface and a nonlinear component, a processing condition of exposure processing is corrected based on the linear component from a previously obtained relation between a dimension of a resist pattern and a processing condition of exposure processing, and thermal processing at the processing temperature corrected in a temperature correcting step and exposure processing under the processing condition corrected in an exposure condition correcting step are performed to form a predetermined pattern.