Dry Etching Process for Semiconductor Trench Sidewall Roughness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dry etching processes for manufacturing semiconductor trench structures result in rough sidewalls, affecting the electrical and mechanical properties of semiconductor chips, and complicate the manufacturing process, especially for three-dimensional integrated circuit chips with high aspect ratios.
Innovation Solution
A dry etching process involving multiple etching gas stages with specific compositions and controlled parameters such as pressure, temperature, and power, including first, second, and third etching gases like sulfur hexafluoride, oxygen, helium, nitrogen trifluoride, and hydrobromic acid, to achieve a deep trench with improved sidewall smoothness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional DRIE process is used to manufacture trenches, then deep trench etching can be achieved, but the sidewall of the trench becomes rough
Solution Approach 1:
The etching process is divided into multiple stages with different gas compositions and parameters. The first stage uses CF4/O2/He mixture for initial etching, the second stage uses SF6/C4F8/He mixture for sidewall smoothing, and the third stage uses CF4/CHF3/He mixture for final etching. This segmentation allows each stage to optimize for its specific function, achieving both deep etching and smooth sidewalls.
Solution Approach 2:
The patent employs periodic alternation between etching and smoothing cycles. Within each cycle, etching gas is introduced followed by smoothing gas, creating periodic action that progressively improves sidewall quality while maintaining etching progress. This periodic action is repeated multiple times to achieve the desired sidewall smoothness.
2Productivity
If three-dimensional stacking technique is employed to increase component density, then functional density is improved, but the manufacturing process becomes more complex and yield decreases
Solution Approach 1:
The patent systematically changes multiple process parameters including gas flow rates, pressure, temperature, and power across different etching stages. By optimizing these parameters, the process achieves high aspect ratio trenches with smooth sidewalls, thereby improving yield for three-dimensional stacked devices without requiring overly complex manufacturing steps.
3Manufacturing precision
If multiple etching stages with different gas compositions are used, then sidewall smoothness is improved, but the etching process time increases
Solution Approach 1:
The etching and smoothing operations are performed in continuous sequence without breaking the vacuum chamber or interrupting the process flow. The transition between different gas compositions is seamless, maintaining continuous useful action on the trench structure. This continuity minimizes idle time and maintains process efficiency despite multiple stages.
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
The process enhances the quality and stability of semiconductor trench manufacturing, reducing sidewall roughness and increasing yield by achieving a high aspect ratio trench with precise control over etching parameters.
Implementation Method 1
introducing a first etching gas into the reaction chamber to perform a first etching process
Implementation Method 2
the first etching gas comprising sulfur hexafluoride, oxygen, helium, nitrogen trifluoride and a first organic silicide
Data Source
AI summary
A dry etching process for manufacturing a trench structure of a semiconductor apparatus, including the steps of: step 1, providing a semiconductor substrate, wherein the semiconductor substrate is provided with a patterned photoresist layer and placed in a reaction chamber; step 2, introducing a first etching gas into the reaction chamber to perform a first etching process to form a trench, wherein the first etching gas includes sulfur hexafluoride, oxygen, helium, nitrogen trifluoride, and a first organic silicide; step 3, introducing a second etching gas into the reaction chamber to perform a second etching process to further etch the trench, wherein the second etching gas includes sulfur hexafluoride, oxygen, helium, and a second organic silicide; and step 4, introducing a third etching gas into the reaction chamber to perform a third etching process, wherein the third etching gas includes hydrobromic acid, oxygen, and helium.