Substrate Coating Transfer Control for Uniform Film Evaporation
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Solution Overview
Problem
The existing substrate treating processes face issues with non-uniform evaporation rates of treating liquids due to non-uniform air flow, leading to thickness uniformity and critical dimension (CD) precision problems in the lithography process.
Innovation Solution
A substrate treating apparatus and method that includes controlled rotational velocities during coating and edge bead removal processes, with specific rotational velocities for different steps to enhance liquid film thickness uniformity and CD precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the substrate waits in a stop state in the treating chamber, then the transfer robot can prepare for the next transfer operation, but the non-uniform descending air flow causes evaporation rate differences of treating liquid across different positions of the substrate
Solution Approach 1:
The substrate is made to rotate at a first rotational velocity during the waiting period instead of remaining stationary. This dynamic motion compensates for the non-uniform descending air flow by continuously changing the position of different substrate areas relative to the air flow, thereby maintaining uniform evaporation rate and film thickness across the substrate surface.
2Productivity
If a strong air flow is supplied to an area of the substrate, then the treating liquid is quickly removed from that area, but the evaporation rate becomes excessively large causing non-uniform film thickness
Solution Approach 1:
By rotating the substrate during the waiting period, the system dynamically redistributes the exposure of different substrate areas to the descending air flow. This prevents any single area from being continuously exposed to strong air flow, thereby controlling the evaporation rate and maintaining uniform film thickness while still allowing efficient treating liquid removal.
3Manufacturing precision
If the substrate rotates at a high rotational velocity, then the film thickness uniformity is improved, but the transfer operation becomes more difficult to execute precisely
Solution Approach 1:
The substrate rotational velocity is set to a specific first rotational velocity that is optimized to compensate for air flow non-uniformity without being excessively high. This parameter optimization achieves sufficient film thickness uniformity while maintaining ease of transfer operation. The controller precisely controls the substrate to stop at the transfer position, ensuring accurate transfer execution.
4Manufacturing precision
If the substrate rotates during the coating process, then the treating liquid is uniformly distributed across the substrate, but the evaporation rate increases due to exposure to descending air flow
Solution Approach 1:
The substrate rotation is implemented as a periodic action with different rotational velocities for different process stages. During coating, the substrate rotates to ensure uniform liquid distribution. During the waiting period, it continues rotating at a first rotational velocity to maintain uniformity while minimizing evaporation. This periodic control of rotation velocity optimizes both uniformity and evaporation control.
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 apparatus and method effectively suppress differences in evaporation rates across the substrate, enhancing thickness uniformity and CD precision by controlling rotational velocities and air flow distribution.
Implementation Method 1
the controller controls the substrate for which the coating process is terminated in the first unit to rotate at a first rotational velocity until the substrate is transferred by the transfer unit
Implementation Method 2
there is an evaporation rate difference of a treating liquid for each position of the substrate due to the non-uniform descending air flow
Data Source
AI summary
Disclosed is an apparatus for treating a substrate, which includes: a first unit configured to perform a coating process of forming a film on a substrate; a transfer unit including a transfer robot transferring a substrate for which the coating process is terminated; and a controller controlling the first unit and the transfer unit, in which the controller controls the substrate for which the coating process is terminated in the first unit to rotate at a first rotational velocity until the substrate is transferred by the transfer unit.