Molybdenum Etching Solution With PEI for Uniform Recessing
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Solution Overview
Problem
Existing etching solutions for molybdenum in semiconductor manufacturing often result in uneven etching rates, leading to top-bottom differences in recessing amounts, which can cause device problems and reduce yield.
Innovation Solution
A chemical solution comprising a mixed acid with an inorganic acid, oxidizing agent, carboxylic acid, and water, combined with polyethyleneimine (PEI) at concentrations between 0.05 wt % and 10 wt %, is used for etching molybdenum layers in semiconductor devices, reducing the etching rate and minimizing top-bottom differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing etching solutions are used for molybdenum, then etching process can be completed, but uneven etching rates occur leading to top-bottom differences in recessing amounts
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by adding polyethyleneimine (PEI) at concentrations of 0.05-10 wt%, and adjusts the ratios of inorganic acid (40-80 wt%), oxidizing agent (1-10 wt%), and carboxylic acid (10-50 wt%). These parameter changes reduce the etching rate and minimize top-bottom differences in recessing amounts, achieving more uniform etching across the molybdenum layer.
Solution Approach 2:
The patent creates a composite etching solution system combining multiple chemical components: inorganic acid (phosphoric acid, sulfuric acid, or nitric acid), oxidizing agent (hydrogen peroxide, potassium permanganate, or ammonium persulfate), carboxylic acid (acetic acid, propionic acid, or butyric acid), and polyethyleneimine. This composite formulation works synergistically to achieve uniform etching rates and high device yield.
2Productivity
If higher etching rate is achieved, then productivity increases, but top-bottom differences in recessing amounts increase
Solution Approach 1:
The patent optimizes the concentration of polyethyleneimine (0.05-10 wt%) to control the etching rate. By adjusting this parameter, the solution achieves a balanced etching rate that maintains productivity while ensuring uniform recessing across the entire molybdenum layer, eliminating top-bottom differences.
Solution Approach 2:
Polyethyleneimine acts as an intermediary substance in the etching solution that mediates between the aggressive etching components (inorganic acid and oxidizing agent) and the molybdenum layer. It provides controlled interaction, ensuring uniform etching progression from top to bottom while maintaining efficient material removal.
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 use of the chemical solution with PEI significantly reduces the top-bottom difference in recessing amounts, improving the yield of semiconductor devices by ensuring more uniform etching of molybdenum layers.
Implementation Method 1
a chemical solution comprises a mixed acid including an inorganic acid, an oxidizing agent, a carboxylic acid, and water; and polyethyleneimine
Implementation Method 2
a mixed acid including an inorganic acid, an oxidizing agent, a carboxylic acid, and water
Data Source
AI summary
According to one embodiment, a chemical solution comprises a mixed acid including an inorganic acid, an oxidizing agent, a carboxylic acid, and water; and polyethyleneimine of a concentration in the chemical solution in a range of 0.05 wt % to 10 wt %.