Cooling Plate Temperature Control for Heat Treatment Uniformity
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Solution Overview
Problem
Conventional heat treatment apparatuses face challenges in maintaining uniform cooling temperatures for substrates, leading to variations in resist film thickness and pattern quality due to inadequate cooling mechanisms, which result in increased treatment time and maintenance complexity.
Innovation Solution
A heat treatment apparatus with a hot plate and cooling plate, where a control unit adjusts the heating mechanism to maintain a temperature difference of 10°C between successive substrates, allowing the cooling plate to be heated or cooled using a gas-based cooling mechanism, eliminating the need for bulky cooling systems like Peltier elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling mechanism such as Peltier elements or cooling pipes is provided inside or under the cooling plate, then the cooling capability is improved, but the apparatus becomes bulky and maintenance work becomes complicated
Solution Approach 1:
The invention extracts the cooling mechanism from the cooling plate structure, eliminating Peltier elements and cooling pipes. Instead, the cooling plate is designed to be cooled by contact with a cooled substrate, transferring heat from the substrate to the plate through direct thermal contact. This simplifies the apparatus structure while maintaining cooling capability.
Solution Approach 2:
The cooling plate utilizes the substrate itself as the cooling source. The substrate, after being cooled by the plate, is then used to cool the plate in preparation for the next substrate. This self-service mechanism eliminates the need for external active cooling systems, reducing apparatus complexity.
2Device complexity
If the cooling mechanism is not provided, then the apparatus structure is simplified, but the cooling plate temperature gradually increases with successive wafers, reducing cooling capability and causing temperature variation
Solution Approach 1:
The invention applies preliminary cooling action by cooling the cooling plate before each substrate is placed on it. The control unit monitors the plate temperature and activates cooling (through substrate contact or external cooling means) to maintain the plate at an appropriate temperature before the next heat treatment cycle, ensuring consistent cooling performance across multiple wafers.
Solution Approach 2:
The invention implements feedback control by using a temperature sensor to continuously monitor the cooling plate temperature and a control unit to adjust cooling operations accordingly. When the plate temperature exceeds a predetermined threshold, the control unit activates cooling mechanisms to maintain temperature uniformity, ensuring consistent cooling capability for successive substrates.
3Device complexity
If the cooling capability of the cooling plate is insufficient, then the apparatus structure is simpler, but the temperature of the cooling plate and substrate gradually increases, causing variation in resist film thickness and pattern
Solution Approach 1:
The control unit uses temperature sensor feedback to monitor both the cooling plate and substrate temperatures. When temperature rises exceed predetermined thresholds, the control unit activates cooling operations to maintain temperatures within ranges that ensure uniform resist film thickness and pattern quality across all processed wafers.
Solution Approach 2:
The system performs preliminary cooling of the cooling plate before each substrate processing cycle to ensure the plate is at the optimal temperature for achieving uniform cooling. This preliminary action prevents temperature drift that would otherwise cause variations in resist film properties.
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 consistent cooling temperatures among substrates, reducing variations in heat treatment and allowing for higher throughput without the need for complex cooling systems, thereby improving the uniformity of resist film thickness and pattern quality.
Implementation Method 1
a cooling plate for cooling the substrate
Implementation Method 2
a heating mechanism for heating the cooling plate
Data Source
AI summary
An experiment is conducted in advance, for finding a temperature of a cooling plate attained as a result of balancing between a temperature of a substrate after heat treatment and a temperature of the cooling plate at the time of cooling of the substrate. Then, before heat treatment of a first substrate, the cooling plate is moved to a position above a hot plate, the cooling plate is heated to that temperature, and thereafter heat treatment of the substrate is started.