High-Density Plasma Deposition for STI Flake Defect Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shallow trench isolation (STI) processes face challenges in preventing wafer defects, particularly 'flake' defects caused by contaminated or damaged layers, which degrade yield due to large flakes peeling off during STI formation.
Innovation Solution
The method involves forming isolation trenches and filling them with multiple high-density plasma depositions, where the first dielectric layer is deposited at a high-frequency power of approximately 100 to 900 watts, reducing flake defects by ensuring better fill and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple high-density plasma depositions are performed with controlled high-frequency power, then flake defects are reduced and yield is improved, but process complexity and deposition time increase
Solution Approach 1:
The dielectric fill process is divided into multiple separate deposition steps rather than a single continuous deposition. Each deposition step uses controlled high-frequency power (100-900 watts) to deposit a portion of the dielectric material. This segmentation allows better control over the deposition process, preventing flake defects by ensuring uniform material placement and avoiding conditions that cause contamination layers to peel off.
Solution Approach 2:
The process employs periodic deposition cycles with intermittent pauses between deposition steps. During each cycle, high-frequency power is applied for a controlled duration to deposit a specific thickness of dielectric material, then the process pauses before proceeding to the next cycle. This periodic action allows monitoring and control of the deposition quality, preventing flake formation while maintaining process efficiency.
2Manufacturing precision
If multiple high-density plasma depositions are performed, then fill uniformity is improved, but manufacturing time increases
Solution Approach 1:
Each deposition step deposits only a portion of the required dielectric thickness rather than attempting to deposit the full thickness in a single step. The high-frequency power (100-900 watts) is carefully controlled to deposit thin, uniform layers that can be precisely monitored. Multiple partial depositions collectively achieve the required total thickness with superior uniformity compared to a single excessive deposition step.
Solution Approach 2:
The multiple deposition steps are performed in continuous sequence with minimal interruption between steps. The plasma process parameters are maintained consistently across all deposition steps, ensuring continuous useful action in building up the dielectric fill. This continuous approach maintains process efficiency while achieving superior uniformity through the segmented deposition strategy.
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 flake defects, improving yield by ensuring better fill and uniformity in STI regions, even as device sizes shrink, by using multiple high-density plasma depositions with controlled high-frequency power.
Implementation Method 1
multiple high-density plasma depositions to deposit multiple dielectric layers
Implementation Method 2
multiple high-density plasma depositions to deposit multiple dielectric layers over the semiconductor body
Data Source
AI summary
One embodiment of the present invention relates to a method of forming an isolation structure. During this method, an isolation trench is formed within a semiconductor body. After this trench is formed, it is filled by performing multiple high-frequency plasma depositions to deposit multiple dielectric layers over the semiconductor body. A first of the multiple layers is deposited at a high-frequency power of between approximately 100 watts and approximately 900 watts.