Titanium Nitride Hard Mask Removal via Selective Liquid Cleaning
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Solution Overview
Problem
Current methods for removing titanium nitride hard masks during semiconductor fabrication inadequately suppress damage to copper, copper alloys, cobalt, and cobalt alloys, leading to ineffective pattern formation and increased risk of metal wiring damage.
Innovation Solution
A liquid cleaning composition comprising hydrogen peroxide (1-30% by mass), potassium hydroxide (0.01-1% by mass), aminopolymethylene phosphonic acid (0.0001-0.05% by mass), and a compound with a group 13 element (0.00005-0.5% by mass), such as aluminum or gallium salts, is used to effectively remove titanium nitride hard masks while minimizing corrosion of cobalt and copper materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning methods (oxygen plasma ashing, cleaning solutions) are used to remove photoresist and dry etch residue, then the photoresist pattern and residue are removed, but damage occurs to metal wiring materials (copper, cobalt, and their alloys)
Solution Approach 1:
The invention changes the chemical parameters of the cleaning solution by specifying precise concentration ranges for hydrogen peroxide (1-30% by mass), potassium hydroxide (0.01-1% by mass), and aminopolymethylene phosphonic acid (0.0001-0.05% by mass). These parameter adjustments optimize the solution's etching selectivity to remove hard mask while minimizing damage to metal wiring materials.
Solution Approach 2:
The invention uses a composite cleaning solution containing multiple chemical components (hydrogen peroxide, potassium hydroxide, aminopolymethylene phosphonic acid, and a compound with group 13 element) that work synergistically. This composite formulation provides both effective hard mask removal and protection of metal wiring through the combined actions of oxidation, alkaline cleaning, and chelating agents.
2Productivity
If a cleaning composition with high etching power is used to remove titanium nitride hard mask, then the hard mask is effectively removed, but corrosion of cobalt and copper materials increases
Solution Approach 1:
The invention optimizes the concentration parameters of each component to achieve the right balance between etching power and selectivity. The hydrogen peroxide concentration (1-30% by mass) provides oxidation capability for hard mask removal, while the potassium hydroxide (0.01-1% by mass) and aminopolymethylene phosphonic acid (0.0001-0.05% by mass) concentrations are controlled to prevent excessive corrosion of cobalt and copper materials.
Solution Approach 2:
The aminopolymethylene phosphonic acid and compound with group 13 element act as intermediaries that selectively interact with titanium nitride to facilitate its removal while forming protective complexes with cobalt and copper, thereby reducing their corrosion. These intermediary substances mediate between the aggressive oxidizing environment and the sensitive metal wiring materials.
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 the precise removal of titanium nitride hard masks with minimal damage to metal wiring, ensuring high-quality semiconductor device fabrication by maintaining low etch rates for cobalt and copper materials.
Implementation Method 1
a liquid cleaning composition for removing a titanium nitride hard mask while suppressing damage to copper, a copper alloy, cobalt or a cobalt alloy... comprising hydrogen peroxide at 1-30% by mass
Implementation Method 2
aminopolymethylene phosphonic acid at 0.0001-0.05% by mass, a compound having a group 13 element at 0.00005-0.5% by mass
Data Source
AI summary
Liquid cleaning compositions for removing a titanium nitride hard mask while suppressing damage to copper, a copper alloy, cobalt or a cobalt alloy upon fabricating a semiconductor device, a cleaning method using the same, and a method for fabricating a semiconductor device, which comprise hydrogen peroxide at 1-30% by mass, potassium hydroxide at 0.01-1% by mass, aminopolymethylene phosphonic acid at 0.0001-0.05% by mass, a compound having a group 13 element at 0.00005-0.5% by mass, and water.