Intermittent Developing Solution Supply for Wafer Processing
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Solution Overview
Problem
Conventional developing methods, such as the stationary puddle scheme, face challenges with resist processing due to hydrophobic properties leading to pullback phenomena, resulting in incomplete development and high solution consumption, while the puddleless scheme requires longer developing times and increased solution usage, especially for low-dissolving resist materials or fine patterns.
Innovation Solution
A developing apparatus and method that involves intermittently supplying developing solution to the center of a rotating substrate, with controlled rotation rates and nozzle movement to prevent drying, ensuring efficient resist dissolution and even coating, thereby reducing solution consumption and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of developing solution is supplied to cover the entire wafer surface, then complete development is achieved, but solution consumption increases
Solution Approach 1:
The developing solution supply is performed intermittently rather than continuously. The supply is divided into multiple stages: initial supply to start development, intermediate supply to maintain development, and final supply to complete development. This periodic action reduces overall solution consumption while ensuring complete development at each stage.
Solution Approach 2:
The wafer rotation speed is dynamically adjusted during the developing process. Higher rotation speeds are used initially to distribute solution quickly, then reduced to maintain an optimal liquid film for continued development. This dynamic control optimizes solution distribution and reduces consumption.
2Loss of substance
If the stationary puddle scheme is used to reduce solution consumption, then solution usage decreases, but pullback phenomenon occurs causing incomplete development
Solution Approach 1:
Multiple intermittent supply stages prevent the liquid film from becoming too thin and causing pullback. By replenishing solution at controlled intervals, the liquid film maintains sufficient thickness for complete development without excessive solution accumulation.
Solution Approach 2:
The developing process maintains continuous useful action through intermittent supply. The wafer continues to rotate and the development process continues uninterrupted, with solution replenished at optimal moments to maintain the liquid film without breaking the development continuity.
3Productivity
If the puddleless scheme with continuous solution supply is used, then development efficiency improves, but solution consumption increases for low-dissolving resist materials
Solution Approach 1:
The continuous supply is replaced with periodic intermittent supply tailored to low-dissolving resist materials. Longer intervals between supply stages allow sufficient time for dissolution, reducing overall solution consumption while maintaining development efficiency for challenging resist types.
Solution Approach 2:
Processing parameters including rotation speed, supply amount, and interval timing are optimized specifically for low-dissolving resist materials. These parameter adjustments ensure efficient development of difficult-to-dissolve patterns while minimizing solution usage.
4Manufacturing precision
If the wafer rotation speed is increased to improve solution distribution, then coating uniformity improves, but solution consumption increases
Solution Approach 1:
Rotation speed is dynamically controlled at different stages: higher speeds during initial supply for rapid distribution, then reduced speeds during intermediate stages to maintain uniform liquid film with lower solution consumption. This dynamic adjustment achieves uniform coating without excessive solution usage.
Solution Approach 2:
The rotation speed varies periodically with the intermittent supply stages. Each supply stage is accompanied by optimized rotation speed control, creating a periodic pattern of high-speed distribution followed by lower-speed maintenance, achieving uniformity efficiently.
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 approach accelerates the developing process, reduces solution consumption, and prevents dry spots, maintaining efficiency across various resist materials and pattern types without the need for excessive solution usage.
Implementation Method 1
by the rotation of the wafer (centrifugal force), the dissolved components of the resist can be removed together with the developing solution during the development
Implementation Method 2
a pullback phenomenon, i.e., drops of solution on wafer W pulling at each other by surface tension, occurs if the amount of developing solution accumulated on wafer W is too small
Implementation Method 3
the dissolved components of the resist can be removed together with the developing solution during the development
Data Source
AI summary
A developing apparatus, a developing processing method, a developing processing program, and a computer readable recording medium recording the program, which can reduce the consumption amount of the developing solution and the developing processing time irrespective of the type of resist materials or the shape of resist patterns, are provided. A step of horizontally holding a substrate and rotating the substrate around a vertical axis at a prescribed rotation rate, and a step of intermittently supplying a developing solution to a center of the substrate from a discharge port of a developing solution nozzle arranged opposing to the surface of the substrate are executed. In the step of intermittently supplying the developing solution to the center of the substrate, an intermittence time and a substrate rotation rate in the intermittence time are set to prevent the developing solution supplied to the substrate from drying.