Plasma CVD Layer Formation Across Different-Density Pattern Regions
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Solution Overview
Problem
The plasma CVD method struggles to form uniform layers on substrates with low-density and high-density pattern regions, resulting in thickness variations due to differing material filling rates in recesses, leading to inconsistent layer formation.
Innovation Solution
A method involving sequential plasma formation and etching steps using precursor and carrier gases with high-frequency voltage, where layers are formed and etched to specific heights in low-density and high-density pattern regions, followed by additional layer formation to achieve uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma CVD method is used to form a layer on substrates with different-density pattern regions, then the layer formation process is simple and efficient, but the layer thickness becomes non-uniform due to differing material filling rates in recesses
Solution Approach 1:
The patent divides the layer formation process into multiple sequential steps (first layer formation, first etching, second layer formation) to address different regions separately. This segmentation allows differential treatment of low-density and high-density pattern regions, enabling thickness uniformity across varying substrate geometries while maintaining overall process efficiency.
Solution Approach 2:
The patent applies local quality by performing selective etching where the first layer is etched to different heights in different regions (higher in low-density regions, lower in high-density regions). This localized modification compensates for the non-uniform material filling that occurs during plasma CVD, achieving uniform final layer thickness across different pattern densities.
2Productivity
If a single layer is formed by plasma CVD on both low-density and high-density pattern regions, then the process is simple and fast, but the material filling amount differs causing inconsistent layer heights
Solution Approach 1:
The patent performs a preliminary layer formation step where the first layer is deposited to fill recesses in both low-density and high-density regions. This preliminary action creates an initial structure that is then selectively modified by etching to achieve the final uniform height, separating the filling function from the height-control function.
Solution Approach 2:
Instead of trying to prevent non-uniform filling during deposition, the patent inverts the approach by intentionally allowing non-uniform filling and then using selective etching to remove excess material from specific regions. This reverse strategy transforms a deposition problem into an etching control problem, achieving uniformity more effectively.
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 ensures high thickness uniformity across both pattern regions by adjusting layer formation and etching processes, reducing initial thickness differences and achieving consistent layer heights.
Implementation Method 1
applying a high-frequency voltage to the gases to form plasma
Implementation Method 2
applying a high-frequency voltage to the gases to form plasma
Implementation Method 3
The plasma CVD method is used as a method for forming a layer such as a carbon layer or a SiC layer on the surface of a substrate
Data Source
AI summary
A method for forming a layer on a low-density pattern region having first recesses and a high-density pattern region having second recesses formed on a substrate to be processed, includes a first step of forming a first layer in the first recesses so as to be higher than the first recess top and forming a second layer in the second recesses so as to be higher than the second recess top, an etching step of etching a first layer so as to be higher than the first recess top and of etching a second layer so as to be lower than the second recess top, and a second step of forming a third layer on the first layer and of forming a fourth layer in the second recesses so as to be higher than the second recess top.