Photoresist Spin Coating With Rapid Braking for Pattern Coverage
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Solution Overview
Problem
The uniformity of photoresist coating in semiconductor manufacturing is compromised when applied to wafers with complex patterns, leading to incomplete coverage and reduced yield, especially for patterns with special shapes like continuous right-angled wires.
Innovation Solution
A photoresist coating method involving a spin coater that starts with a low rotation speed, increases to a high speed, and includes multiple rapid braking phases to rapidly drop and then return to high speed, creating a wave-like motion to ensure complete coverage across obstacles without increasing photoresist amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist is coated using conventional spin coating method, then the coating process is simple, but the photoresist cannot completely cover the whole wafer when the surface has special shapes
Solution Approach 1:
The patent applies dynamics by varying the rotation speed of the spin coater during the coating process. The rotation speed is changed from a first rotation speed to a second rotation speed, creating dynamic motion that enables photoresist to flow into and cover recessed areas of complex patterns, thereby improving coating uniformity without increasing process complexity
Solution Approach 2:
The patent employs periodic action through multiple rapid braking operations during spin coating. The spin coater performs repeated braking cycles, creating periodic motion that helps photoresist penetrate and cover the entire wafer surface, including areas with special shapes, while maintaining a relatively simple coating process
2Manufacturing precision
If photoresist injecting amount is increased to cover complex patterns, then coverage may improve, but the photoresist amount increases and yield is still affected
Solution Approach 1:
By dynamically adjusting rotation speed during spin coating, the patent enables complete photoresist coverage of complex patterns without increasing the photoresist injecting amount. The variable speed motion ensures photoresist reaches all areas, including recessed regions, while maintaining efficient material usage and improving yield
3Productivity
If conventional spin coating is used on wafers with special shapes, then the process is fast, but photoresist gets stuck in pattern obstructions and coverage is incomplete
Solution Approach 1:
The patent maintains high productivity by performing multiple rapid braking operations during spin coating. These periodic braking actions create motion that helps photoresist overcome pattern obstructions and reach recessed areas, ensuring complete coverage while keeping the overall process fast and efficient
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 method ensures uniform photoresist coating across complex patterns, improving yield by preventing photoresist from getting stuck in pattern obstructions and maintaining complete coverage without additional photoresist, thus enhancing the semiconductor manufacturing process.
Implementation Method 1
turning on the photoresist spin coater to make the photoresist spin coater rotate to a first rotation speed, increasing the first rotation speed to a second rotation speed
Implementation Method 2
performing multiple rapid braking in the process of maintaining the second rotation speed, so that the second rotation speed instantly drops to a third rotation speed
Data Source
AI summary
The invention provides a photoresist coating method, which comprises the following steps: providing a wafer with a pattern on the wafer, placing the wafer on a spinner, injecting a photoresist on a central region of the wafer from a nozzle, and carrying out a spin coating step, the spin coating step comprises: turning on the spinner to rotate the spinner to a first rotation speed, and raising the first rotation speed to a second rotation speed, and performing a plurality of brakes during the process of maintaining the second rotation speed, so that the second rotation speed instantly drops to a third rotation speed, and then rises to the second rotation speed again.