Spin Coating Nozzle Radial Motion and Speed Control
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Solution Overview
Problem
The existing spin coating methods for semiconductor manufacturing are prone to forming coating mottle due to variations in the discharge state of the resist solution, leading to non-uniform resist films and potential failures in pattern formation during exposure processing.
Innovation Solution
A coating treatment apparatus and method that involves a rotating substrate with a nozzle moving along a radial direction from the central to an eccentric position, controlling rotation speeds to form a solution puddle and ensure the solution droplet from the nozzle fits into the puddle, preventing distortion and achieving uniform coating film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the discharge of resist solution from the nozzle is stopped during high-speed rotation, then the coating process is completed, but a solution droplet drops and forms a coating mottle
Solution Approach 1:
The patent applies preliminary action by decelerating the substrate rotation speed before stopping the resist solution discharge. This preparatory deceleration prevents the formation of solution droplets that would otherwise drop and cause coating mottle, ensuring uniform coating without requiring additional corrective measures.
Solution Approach 2:
The patent applies preliminary anti-action by counteracting the centrifugal force that causes solution droplet formation through controlled deceleration. By reducing the rotation speed before discharge stops, the centrifugal force is reduced, preventing the harmful droplet formation that would occur if discharge stopped during high-speed rotation.
2Manufacturing precision
If the rotation speed of the substrate is decreased to prevent solution droplet formation, then coating uniformity is improved, but the centrifugal force acting on the resist solution is reduced
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the substrate rotation speed during the coating process. The rotation speed is changed from a first speed during discharge to a second, lower speed before discharge stops, and then to a third, higher speed after discharge stops. This dynamic adjustment optimizes both coating uniformity and centrifugal force at different stages of the process.
Solution Approach 2:
The patent applies periodic action through the three-stage rotation speed profile: high speed during discharge, low speed during the transition period before discharge stops, and high speed again after discharge stops. This periodic variation in rotation speed ensures uniform coating while maintaining sufficient centrifugal force when needed.
3Quantity of substance
If a small amount of resist solution is used to reduce cost, then material cost is reduced, but the coating is more sensitive to discharge state variations
Solution Approach 1:
The patent applies parameter changes by modifying the rotation speed parameter at different stages of the coating process. By changing the rotation speed from first to second speed before discharge stops, and then to third speed after discharge stops, the patent ensures uniform coating thickness even when using a small amount of resist solution, making the coating less sensitive to discharge state variations.
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 ensures high uniformity of the coating film by controlling the rotation speeds and nozzle position, preventing the formation of coating mottle and ensuring consistent film thickness across the substrate.
Implementation Method 1
supplying the coating solution onto a central portion of the substrate and rotating the substrate at a first rotation speed to spread the coating solution to a peripheral portion of the substrate by a centrifugal force
Data Source
AI summary
A coating treatment apparatus includes: a rotating and holding part; a nozzle supplying a coating solution; a moving mechanism moving the nozzle; and a control unit that controls the rotating and holding part, the nozzle, and the moving mechanism to supply the coating solution onto a central portion of the substrate and rotate the substrate at a first rotation speed, then move a supply position of the coating solution from a central position toward an eccentric position of the substrate with the substrate being rotated at a second rotation speed lower than the first rotation speed while continuing supply of the coating solution, then stop the supply of the coating solution with the rotation speed of the substrate decreased to a third rotation speed lower than the second rotation speed, and then increase the rotation speed of the substrate to be higher than the third rotation speed.