SiGe Selective Etching Solution for Stable Semiconductor Manufacturing
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Solution Overview
Problem
Existing etching solutions for SiGe compounds in semiconductor manufacturing often result in etching stops and unintentional etching of Si layers, leading to unstable transistor characteristics and reduced yield, due to the complexity and inefficiency of current methods.
Innovation Solution
An etching solution comprising hydrofluoric acid, nitric acid, and water, with specific concentration ranges (0.002-1.0% for hydrofluoric acid, 10-55% for nitric acid, and up to 40% for water), which selectively etches SiGe compounds while preventing etching stops and improving etching rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fluorine nitric acid solution is used for selective etching of SiGe layer, then high etching ratio for SiGe is achieved, but etching stops occur after prolonged etching time
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by adding acetic acid and adjusting the concentrations of hydrofluoric acid, nitric acid, and water. This parameter change enables the solution to maintain stable etching performance over extended periods without etching stops, resolving the contradiction between selectivity and duration.
2Productivity
If conventional etching solution is used for prolonged etching, then complete SiGe removal is achieved, but unintentional Si layer etching occurs
Solution Approach 1:
The patent optimizes the concentration parameters of hydrofluoric acid (0.002-1.0%), nitric acid (10-55%), and acetic acid (5-40%) to achieve a balanced etching rate. This parameter optimization allows prolonged etching to remove complete SiGe layers while maintaining control and preventing unintentional Si layer etching.
3Reliability
If multiple etching steps with water washing are implemented, then etching stop problem is solved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the water washing steps from the etching process by formulating a single etching solution that inherently prevents etching stops through the addition of acetic acid. This eliminates the need for repeated immersion and washing operations, reducing process complexity while maintaining reliability.
Solution Approach 2:
The patent combines multiple functions into a single etching solution formulation that provides both selective etching capability and prevention of etching stops. The merged solution eliminates the need for separate etching and washing steps, simplifying the overall process while maintaining stability.
4Loss of time
If conventional etching solution is used, then short etching time is required, but etching stops occur and yield deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by incorporating acetic acid and optimizing the ratios of other components. This enables prolonged etching times to be used effectively, improving yield by allowing complete SiGe removal without etching stops while maintaining reasonable process efficiency.
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 solution enables stable and selective etching of SiGe compounds, suppressing etching stops and improving etching uniformity, thereby enhancing manufacturing efficiency and reducing costs by allowing longer etching times without complex process steps.
Implementation Method 1
an etching solution containing hydrofluoric acid (DHF) and nitric acid has a high etching ratio for a SiGe compound with respect to Si, SiO2, and the like
Implementation Method 2
an etching solution containing hydrofluoric acid (DHF) and nitric acid has a high etching ratio for a SiGe compound
Data Source
AI summary
An etching solution for selectively performing an etching process on a compound represented by General Formula Si1-xGex, in which x is more than 0 and less than 1, with respect to Si, Ge, and oxides thereof, the etching solution including hydrofluoric acid, nitric acid, and water, in which a content ratio of the hydrofluoric acid in the entire etching solution is 0.002% by mass or more and 1.0% by mass or less, a content ratio of the nitric acid in the entire etching solution is 10% by mass or more, and a content ratio of the water in the entire etching solution is 40% by mass or less.