Polysilazane Deposition for Void-Free Trench Isolation
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Solution Overview
Problem
The reaction of trisilylamine, oxygen, and ammonia gas under plasma treatment in shallow trench isolation processes for semiconductor wafers often results in defects such as voids, leading to electrical isolation failures, especially for nano-scale line widths.
Innovation Solution
A method involving the deposition of polysilazane on semiconductor wafers, where silazane is dissolved in a solvent like ammonia, applied at controlled cooling temperatures, and then heated to form a void-free polysilazane layer, which is subsequently converted into oxide, ensuring full trench filling without defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plasma treatment is used to form polysilazane from trisilylamine, oxygen, and ammonia gas, then the polysilazane layer can be formed with good flowability over oxide, but voids and defects occur in the polysilazane layer
Solution Approach 1:
The patent extracts the harmful plasma treatment step from the polysilazane formation process. Instead of using plasma to form polysilazane from trisilylamine, oxygen, and ammonia gas, the invention uses a different approach: forming a silicon nitride layer first, then converting it to polysilazane through chemical vapor deposition with silane and ammonia, eliminating the violent plasma reaction that causes voids while maintaining good flowability
Solution Approach 2:
The patent introduces an intermediary silicon nitride layer as a intermediate step between the substrate and the final polysilazane layer. This silicon nitride layer serves as a mediator that can be converted to polysilazane through a controlled chemical process, avoiding the direct violent plasma reaction between trisilylamine, oxygen, and ammonia gas that causes defects
2Productivity
If conventional plasma treatment is used for polysilazane formation, then the process can be completed in a single step, but voids and defects are unavoidable
Solution Approach 1:
The patent segments the polysilazane formation process into multiple controlled steps: first forming a silicon nitride layer, then converting it to polysilazane through chemical vapor deposition. This segmentation allows each step to be optimized independently, ensuring void-free formation while maintaining overall process efficiency, particularly for narrow trench structures
Solution Approach 2:
The patent performs preliminary action by forming a silicon nitride layer before converting it to polysilazane. This preliminary silicon nitride layer provides a stable foundation that can be uniformly converted to polysilazane, preventing void formation and ensuring reliable isolation, especially for nanometer-scale line widths
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 prevents voids in the polysilazane layer, enabling reliable electrical isolation for nano-scale trench structures, improving the yield rate and insulation quality in semiconductor manufacturing.
Implementation Method 1
heating the silazane to form the polysilazane on the semiconductor wafer
Implementation Method 2
the polysilazane is converted into oxide
Data Source
AI summary
A method for depositing a polysilazane on a semiconductor wafer is provided. The method includes steps of disposing a silazane onto the semiconductor wafer, and heating the silazane to form the polysilazane on the semiconductor wafer. An apparatus for preparing a polysilazane on a semiconductor wafer is also provided.