Photoresist Buffer for Microloading in Semiconductor Etching
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Solution Overview
Problem
The microloading effect in traditional dry etching processes leads to uneven etching depths across dense and isolated regions on semiconductor substrates, resulting from differences in pattern size and density, causing variations in etching characteristics.
Innovation Solution
A method involving the formation of dense and isolated feature patterns on a substrate, followed by the application of a photoresist layer that serves as a buffer during dry etching, ensuring uniform etching by using the mask layer as a mask and controlling the etching process to maintain equal depths across both regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional dry etching process is used, then etching can be performed on the substrate, but uneven etching depths occur in dense and isolated regions due to microloading effect
Solution Approach 1:
A photoresist layer is formed in advance to cover the isolated region before the etching process. This preliminary action prevents the etching gas from directly accessing the isolated region, thereby compensating for the microloading effect that would otherwise cause uneven etching depths between dense and isolated regions
Solution Approach 2:
The photoresist layer acts as an intermediary buffer between the etching gas and the isolated region. By introducing this intermediate layer, the patent achieves uniform etching depths across different pattern densities while maintaining the protective function of the mask layer
2Manufacturing precision
If photoresist layer is added to cover isolated region, then etching depth uniformity is improved, but process complexity increases
Solution Approach 1:
The photoresist layer serves multiple functions: it acts as a protective buffer during etching to compensate for microloading effects, and can also serve as a mask layer for subsequent processing steps. This multi-functionality reduces the need for additional separate process steps despite the added complexity
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 effectively reduces the microloading effect, allowing for uniform etching depths across both dense and isolated regions, thereby improving the accuracy and consistency of the etching process.
Implementation Method 1
a photoresist layer is formed to cover the isolated region. Finally, the substrate and the photoresist layer are etched by taking the dense feature pattern and the isolated feature pattern as a mask
Data Source
AI summary
The present invention provides a method of reducing microloading effect by using a photoresist layer as a buffer. The method includes: providing a substrate defined with a dense region and an isolated region. Then, a dense feature pattern and an isolated feature pattern are formed on the dense region and the isolated region respectively. After that, a photoresist layer is formed to cover the isolated region. Finally, the substrate and the photoresist layer are etched by taking the dense feature pattern and the isolated feature pattern as a mask.