Resorcinol-Based Stripper Solutions for Semiconductor Metal Conservation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stripper solutions for semiconductor devices, particularly those containing metals like copper and tungsten, suffer from metal loss due to corrosion during the removal of resist and etch residues, which is unacceptable for sub-micron components, and existing corrosion inhibitors have drawbacks such as residual adhesion, toxicity, and disposal issues.
Innovation Solution
A stripper solution containing resorcinol or its derivatives, which reduces metal etch rates by incorporating a copper salt and optionally an amine, maintaining a metal conservation factor (MCF) between 0 and 1, ensuring minimal metal loss and easy rinsability without toxicity or biodegradability concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strongly alkaline stripper solutions are used to remove resist residues, then stripping efficiency is improved, but metal loss through corrosion increases
Solution Approach 1:
A corrosion inhibitor is introduced as an intermediary substance that mediates between the alkaline stripper solution and the metal components. The inhibitor forms protective films on metal surfaces, preventing direct contact and corrosion while allowing the stripper to effectively remove resist residues. This resolves the contradiction by enabling both efficient stripping and metal conservation simultaneously.
Solution Approach 2:
The pH parameter of the stripper solution is modified by adding corrosion inhibitors that can buffer the alkalinity or form protective complexes. This parameter change allows the solution to maintain sufficient alkalinity for effective stripping while reducing the corrosive attack on metal components, thus resolving the contradiction between stripping efficiency and metal loss.
2Reliability
If corrosion inhibitors are added to reduce metal loss, then metal integrity is improved, but solution complexity and disposal difficulty increase
Solution Approach 1:
The patent employs corrosion inhibitors that are consumed or depleted during the stripping process, particularly in heated dry organic stripping compositions. These inhibitors serve their protective function temporarily and are then disposed of with the spent stripper solution, eliminating the need for complex recovery systems and reducing overall solution complexity while maintaining metal integrity.
Solution Approach 2:
The corrosion inhibitor is discarded along with the spent stripper solution after completing its protective function. This approach simplifies the system by not requiring complex inhibitor recovery or regeneration equipment, while still achieving the goal of protecting metal components during the stripping process.
3Speed
If heated dry organic stripping compositions are used, then stripping speed is improved, but corrosion rate increases due to dissolved oxygen
Solution Approach 1:
The patent converts the harmful effect of dissolved oxygen in heated dry organic stripping compositions into a beneficial outcome by adding corrosion inhibitors that specifically target and neutralize oxygen-induced corrosion. The inhibitors form protective films that prevent oxygen from attacking metal surfaces, allowing the heated dry organic composition to maintain its high stripping speed while eliminating the corrosion problem.
Solution Approach 2:
A corrosion inhibitor acts as an intermediary between the heated dry organic stripping composition and the metal components. It interferes with the cathodic reaction caused by dissolved oxygen, preventing corrosion while allowing the stripping process to proceed at high speed. This mediator enables both fast stripping and corrosion protection simultaneously.
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 effectively reduces metal etch rates, maintains metal integrity, and is environmentally friendly, allowing for efficient removal of resist and etch residues without damaging semiconductor components or increasing toxicity, as demonstrated by reduced copper and TiW etch rates in various stripper formulations.
Implementation Method 1
stripper solutions containing a resorcinol and/or a resorcinol derivative... reduced metal etch rates... incorporating a copper salt... maintains a metal conservation factor (MCF) between 0 and 1
Implementation Method 2
removal of resist and etch residues with chemical stripper solutions... quickly remove resist residues and materials at moderate to low temperatures
Implementation Method 3
remove resist residues and materials... have a substantial capacity for the dissolved resist and/or post etch residue
Data Source
AI summary
Resist stripping agents useful for fabricating circuits and/or forming electrodes on semiconductor devices for semiconductor integrated circuits and/or liquid crystals with reduced metal and metal alloy etch rates (particularly copper etch rates and TiW etch rates), are provided with methods for their use. The preferred stripping agents contain low concentrations of resorcinol or a resorcinol derivative, with or without an added copper salt, and with or without an added amine to improve solubility of the copper salt. Further provided are integrated circuit devices and electronic interconnect structures prepared according to these methods.