Etching Composition for Selective Ni and NiPt Metal Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in selectively etching metals like Ni or NiPt without damaging adjacent materials, as existing compositions often corrode or oxidize surrounding structures, especially as feature sizes decrease, making it difficult to determine the appropriate etching composition for specific device structures.
Innovation Solution
The use of aqueous metal etching compositions containing sulfonic acids, halide anions, and nitrate or nitrosyl ions, optimized to maintain a strongly acidic environment for effective etching of Ni or NiPt films while minimizing oxidation of adjacent materials like NiPtSi, with specific ratios of sulfonic acids, halides, and nitrates to control the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching compositions are used to etch metal films, then etching can be performed, but adjacent materials such as aluminum and nickel platinum silicides are corroded or oxidized
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by using a buffered solution with controlled pH (maintained between 2-10 using buffer components like ammonium fluoride and hydrofluoric acid) and specific concentration ratios of etching agents. This parameter control allows selective etching of metal films while minimizing damage to adjacent materials through optimized chemical environment
Solution Approach 2:
The etching composition is a composite formulation containing multiple components: buffered solution (ammonium fluoride, hydrofluoric acid), complexing agents (ammonia, ammonium hydroxide), and specific additives. This composite composition works synergistically to achieve selective etching while protecting adjacent structures through the combined effects of its constituents
2Productivity
If existing etching compositions are used, then metal etching can proceed, but it is difficult to determine the appropriate composition for specific device structures with varying materials
Solution Approach 1:
The buffered etching composition is designed with universal applicability to etch multiple types of metal films (aluminum, copper, tungsten, nickel, platinum, and their alloys) while simultaneously protecting various adjacent materials (silicon dioxide, silicon nitride, polysilicon). The multi-functional formulation eliminates the need for different compositions for different device structures
3Length of moving object
If feature dimensions are reduced in integrated circuits, then device density increases, but the importance of minimizing damage to adjacent materials increases
Solution Approach 1:
The etching composition exhibits local quality by selectively reacting with specific metal films while leaving adjacent materials unaffected. The buffered solution with pH 2-10 and specific complexing agents creates a chemically selective environment that targets only the intended metal film for etching, providing localized chemical action precisely where needed while preserving surrounding structures
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 described etching compositions effectively etch Ni or NiPt films with minimal damage to adjacent materials, achieving high etch rates and low corrosion of aluminum and oxidation of NiPtSi, thus ensuring precise and reliable semiconductor manufacturing.
Implementation Method 1
aqueous metal etching compositions containing sulfonic acids, halide anions, and nitrate or nitrosyl ions, optimized to maintain a strongly acidic environment for effective etching of Ni or NiPt films
Implementation Method 2
achieving high etch rates and low corrosion of aluminum and oxidation of NiPtSi
Data Source
Figure 1
AI summary
This disclosure relates to an etching composition containing at least one sulfonic acid, at least one compound containing a halide anion, the halide being chloride or bromide, at least one compound containing a nitrate or nitrosyl ion, and water. The at least one sulfonic acid can be from about 25% by weight to about 95% by weight of the composition. The halide anion can be chloride or bromide, and can be from about 0.01% by weight to about 0.5% by weight of the composition. The nitrate or nitrosyl ion can be from about 0.1% by weight to about 20% by weight of the composition. The water can be at least about 3% by weight of the composition.