Spin Chuck Temperature Zoning for Uniform Photoresist Coating
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Solution Overview
Problem
The thickness gradient of photoresist solution on a semiconductor substrate during coating leads to errors in pattern transcription, particularly in the initial stage, which affects subsequent stages.
Innovation Solution
A spin coater with independent temperature control mechanisms for the edge and central regions of the substrate, utilizing thermoelectric elements and transfer members to regulate temperature distribution, controlled by a main controller based on thickness measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photoresist solution is coated on a rotating substrate using centrifugal force, then the photoresist spreads from central portion to edge portion, but a thickness gradient is formed causing pattern transcription errors
Solution Approach 1:
The spin chuck is divided into a first region (central area) and a second region (edge area) with different temperature control characteristics. The first region has higher thermal capacity to maintain stable temperature, while the second region has lower thermal capacity. This local differentiation allows targeted temperature management to compensate for centrifugal force effects and achieve uniform photoresist thickness.
Solution Approach 2:
The system changes the temperature parameter in different regions of the spin chuck during the coating process. By controlling the temperature distribution across the first and second regions, the viscosity and flow characteristics of the photoresist solution are modified locally, compensating for the thickness gradient caused by centrifugal force and achieving uniform coating thickness.
2Device complexity
If temperature is controlled in a single region of the spin chuck, then simple control structure is maintained, but thickness gradient of photoresist cannot be effectively reduced
Solution Approach 1:
The temperature control system is segmented into multiple independent control zones corresponding to different regions of the spin chuck. Each region (first region and second region) has its own temperature control characteristics, allowing differentiated thermal management to address the thickness gradient problem while maintaining a relatively simple overall structure.
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 solution reduces the thickness gradient of the photoresist, ensuring a uniform coating thickness and minimizing pattern transcription errors.
Implementation Method 1
The four first thermoelectric elements may be configured receive a first power from the four first non-contact type power supply devices, respectively, and may be configured to generate a hot air or a cold air
Implementation Method 2
The four first transfer members may be configured to transfer the hot air or the cold air to the edge region of the spin chuck
Implementation Method 3
The photoresist solution on the central portion of the upper surface of the semiconductor substrate may spread to an edge portion of the upper surface of the semiconductor substrate by a centrifugal force of the rotating semiconductor substrate
Data Source
AI summary
A spin coater may include a spin chuck, a nozzle, a first temperature controller and a second temperature controller. The spin chuck may be configured make contact with a central portion of a lower surface of a substrate and may be configured to rotate the substrate when photoresist is on the substrate. The nozzle may be arranged over a central portion of the spin chuck and configured to provide a central portion of an upper surface of the substrate with photoresist. The first temperature controller may be configured to control a temperature in a first region of the spin chuck. The second temperature controller may be configured to control a temperature in a second region of the spin chuck.