Silicon Carbide Wafer Developing Film Thickness Control
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Solution Overview
Problem
Existing methods for manufacturing semiconductor devices, such as those described in Japanese Patent No. 3708433 (2005), do not adequately reduce microbubbles during the developing solution process, leading to pattern defects, particularly in the production of silicon carbide semiconductor devices where wafer costs are high and yield improvements are critical.
Innovation Solution
A method involving a developing solution immersing process where the film thickness of the developing solution is initially set to more than 6 μm and then reduced to 6 μm or less, utilizing a spin chuck or blade to defoam microbubbles, thereby minimizing their adherence to the photoresist film and reducing pattern defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the developing solution is dropped on the semiconductor substrate, then the photoresist film is developed, but microbubbles are generated and adhere to the photoresist film surface causing pattern defects
Solution Approach 1:
The patent applies preliminary action by rotating the semiconductor substrate at high speed (1000-3000 rpm) before dropping the developing solution to pre-remove air bubbles from the photoresist film surface. This preliminary bubble removal prevents microbubbles from adhering during the subsequent developing process, thereby improving pattern quality without compromising development effectiveness
Solution Approach 2:
The patent employs periodic action through a multi-stage rotation process: high-speed rotation (1000-3000 rpm) before dropping developing solution, followed by reduced-speed rotation (300-1000 rpm) during development, and finally high-speed rotation again to remove excess solution. This periodic variation in rotation speed optimizes both bubble removal and pattern development while minimizing microbubble adhesion
2Productivity
If the developing solution is pressurized with nitrogen or air to drop the solution, then the developing solution is delivered effectively, but the dissolved nitrogen foams and generates microbubbles
Solution Approach 1:
The patent applies parameter changes by controlling the pressure of the developing solution delivery system to maintain it at or below atmospheric pressure during the dropping process. This parameter adjustment prevents nitrogen from coming out of solution as foam, thereby eliminating microbubble generation while maintaining effective developing solution delivery to the photoresist film
Solution Approach 2:
The patent uses an inert atmosphere approach by controlling the delivery pressure to prevent nitrogen gas from being introduced into the developing solution. By maintaining pressure conditions that prevent gas dissolution and subsequent foaming, the system avoids generating harmful microbubbles while preserving productive solution delivery
3Productivity
If the semiconductor substrate is rotated at high speed to disperse the rinse solution, then the substrate is dried effectively, but the rinse solution may not adequately stop the development process
Solution Approach 1:
The patent employs periodic action by implementing a multi-stage rotation protocol: high-speed rotation (1000-3000 rpm) before developing to remove bubbles, moderate rotation (300-1000 rpm) during developing to maintain solution contact, and finally high-speed rotation again after development to remove excess rinse solution and dry the substrate. This periodic variation ensures both complete development stopping and effective drying
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that the development stopping function is continuously effective throughout the process. The substrate rotation speed is carefully controlled to maintain adequate rinse solution contact time for complete development stopping, while subsequent high-speed rotation efficiently removes excess solution for drying, thus achieving both reliability and productivity
Data Source
AI summary
A method for manufacturing a semiconductor device includes a photolithography process having steps of a developing solution immersing process. The steps of the developing solution immersing process includes step (a) of dropping a developing solution on a silicon carbide semiconductor substrate and forming a developing solution film so as to have a film thickness of more than 6 μm and step (b) of reducing the film thickness of the developing solution film to 6 μm or less.