Cooled Showerhead Assembly for In-Situ Post-Bake Substrate Cooling
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Solution Overview
Problem
The existing methods for cooling substrates after exposure to high temperatures in photolithography processes are inefficient, leading to prolonged reaction times and potential premature reactions of the resist resin when substrates are transferred outside the process chamber.
Innovation Solution
A method and apparatus for in-situ cooling of substrates using a process chamber with a cooled showerhead assembly and a substrate lifting device to rapidly cool the substrate from 400°C to 70°C within 30 seconds by controlling the distance and proximity to a cooled plate, utilizing gas flow and thermo-electric cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate is moved to a remote location for cooling after post-exposure bake, then the substrate can be cooled down, but the cooling time is prolonged and the resist resin may react prematurely
Solution Approach 1:
The cooling function is merged with the existing process chamber by integrating a cooled plate into the chamber structure. This allows the substrate to be cooled in-situ without being transferred to a separate cooling location, thereby reducing cooling time and preventing premature resist resin reactions.
Solution Approach 2:
A cooled plate is pre-positioned within the process chamber before the substrate is placed on the heated substrate support. This preliminary arrangement of the cooling mechanism ensures that cooling can immediately commence once the substrate is positioned, minimizing the time required to cool the substrate from high temperature.
2Loss of time
If the substrate is cooled rapidly in-situ, then the cooling time is reduced and resist resin reaction is prevented, but the device complexity increases
Solution Approach 1:
The cooled plate within the showerhead assembly serves multiple functions: it acts as a cooling mechanism for the substrate and simultaneously functions as part of the existing process chamber structure. This multi-functionality reduces the need for separate dedicated cooling equipment, thereby limiting the increase in device complexity.
3Device complexity
If the substrate is kept close to the heated substrate support during cooling, then the chamber structure is simpler, but the cooling efficiency is reduced
Solution Approach 1:
The substrate support is designed to be movable, allowing dynamic adjustment of the substrate's position relative to the cooled plate. During cooling, the substrate support moves to position the substrate in close proximity to the cooled plate for efficient heat transfer. This dynamic positioning enables high cooling efficiency while maintaining a relatively simple chamber structure that does not require complex mechanical adjustments.
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 method enables rapid cooling of substrates in-situ, reducing the time required to cool the substrate and minimizing the risk of premature reactions, thereby improving exposure resolution and film integrity.
Implementation Method 1
The substrate is cooled until the substrate is less than about 70 degrees Celsius by the cooled plate of the showerhead
Implementation Method 2
utilizing gas flow and thermo-electric cooling
Implementation Method 3
utilizing gas flow and thermo-electric cooling
Data Source
AI summary
A method and apparatus for performing post-exposure bake cooling operations is described herein. The method begins by post exposure baking a substrate disposed on heated substrate support in a process chamber, the process chamber having a showerhead. The heated substrate support is moved to increase a distance between the heated substrate support and a cooled plate of the showerhead. The substrate is separated from the heated substrate support using a substrate lifting device. The substrate is moved into a close proximity to the cooled showerhead. The substrate is cooled until the substrate is less than about 70 degrees Celsius. The substrate is spaced away from the cooled showerhead using the substrate lifting device and aligning the substrate with a substrate transfer passage of the processing chamber for removal by a robot.