Titanium Layer Etching Composition for Speed-Selectivity Balance
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Solution Overview
Problem
Current etching processes for semiconductor devices face challenges in achieving high etching speed, selectivity, and storage stability for titanium-containing layers while minimizing surface residue, which affects the reliability and integration of semiconductor devices.
Innovation Solution
An etching composition comprising an oxidant, phosphorus-based or chlorine-based inorganic acid, and a nitrogen-containing polymer inhibitor is used, which includes specific repeating units to enhance etching selectivity and control etching rates between different regions of the titanium-containing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching compositions are used to increase etching speed for titanium-containing layers, then etching efficiency is improved, but surface residue increases and storage stability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by specifying precise pH ranges (2-4) and using particular inorganic acids (phosphoric, hydrochloric, or nitric acid within 0.1-10 wt%) to achieve optimal balance between etching speed and storage stability. The oxidant concentration is controlled at 0.1-5 wt% to prevent excessive residue while maintaining effective etching.
Solution Approach 2:
The patent creates a composite etching composition system combining multiple components: inorganic acid, oxidant (hydrogen peroxide, ammonium persulfate, or ammonium persulfate), and specific additives (ammonium fluorosulfonate, ammonium bifluoride, or hydrofluoric acid). This composite approach allows synergistic effects that simultaneously improve etching speed, selectivity, and storage stability while minimizing surface residue.
2Productivity
If etching composition is optimized for high etching speed, then productivity increases, but etching selectivity for adjacent layers deteriorates
Solution Approach 1:
The patent applies local quality by making the etching composition selectively active toward titanium-containing layers while being inert to adjacent layers. This is achieved through controlled pH (2-4) and specific chemical composition that creates different etching rates for different materials, allowing precise patterning without damaging surrounding structures.
Solution Approach 2:
The patent adjusts chemical parameters including pH (2-4), oxidant concentration (0.1-5 wt%), and inorganic acid type/concentration to achieve optimal etching selectivity. These parameter changes ensure that the etching process targets titanium-containing layers specifically while preserving adjacent layers with different material properties.
3Loss of time
If etching composition is designed for fast etching, then processing time decreases, but surface residue on target layer increases
Solution Approach 1:
The patent optimizes the balance between etching speed and residue formation by controlling pH (2-4), oxidant concentration (0.1-5 wt%), and inorganic acid content (0.1-10 wt%). These parameter adjustments ensure complete removal of titanium-containing layers without leaving significant surface residue, eliminating the need for additional cleaning steps.
Solution Approach 2:
The patent ensures continuous effective etching action throughout the process by maintaining optimal chemical conditions that prevent passivation or premature termination. The controlled oxidation and acid dissolution proceed continuously and completely, removing the target layer uniformly without leaving residue that would interrupt the process or require rework.
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 composition provides excellent etching speed and selectivity for titanium-containing layers, improves the efficiency and productivity of the etching process, and ensures minimal surface residue, leading to enhanced semiconductor device performance and reliability.
Implementation Method 1
an oxidant, an inorganic acid, and a selective etching inhibitor
Implementation Method 2
The inorganic acid may include phosphorus-based inorganic acid, chlorine-based inorganic acid, or fluorine-based inorganic acid
Data Source
AI summary
An etching composition for a titanium-containing layer may include an oxidant, an inorganic acid, and a selective etching inhibitor. The inorganic acid may include phosphorus-based inorganic acid, chlorine-based inorganic acid, or fluorine-based inorganic acid, or any combination thereof. The selective etching inhibitor may include a polymer having a nitrogen-containing repeating unit.