Photolithography Stripping Solution pH Control for SiO2 Corrosion
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Solution Overview
Problem
Existing stripping solutions for photolithography are insufficient in anticorrosion properties on SiO2 and various metal materials, and tend to corrode SiO2 films during the semiconductor manufacturing process.
Innovation Solution
A stripping solution containing hydrofluoric acid and a specific basic compound, with a pH adjusted to a range of not more than 6.0 or 8.5, effectively strips residual photoresist and etching materials while providing excellent anticorrosion properties on SiO2 and metals, using a combination of hydrofluoric acid, a basic compound, water, and optional pH adjusters and organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stripping solutions (hydrofluoric acid with ammonia or 1,8-diazabicyclo[5.4.0]undecene-7) are used to effectively strip residual photoresist and etching materials, then stripping performance is improved, but anticorrosion properties on SiO2 and metal materials deteriorate
Solution Approach 1:
The patent changes the pH parameter of the stripping solution to a basic range (pH 9-14) to resolve the contradiction. This pH adjustment fundamentally alters the chemical environment, enabling the solution to strip photoresist and etching materials effectively while simultaneously preventing corrosion of SiO2 and metal materials. The basic pH creates conditions where the stripping agents can function without being corrosive to the underlying structures.
Solution Approach 2:
The patent employs a composite chemical formulation containing multiple components: hydrofluoric acid (0.01-5 wt%), a basic compound (1-50 wt%), and a chelating agent (0.1-10 wt%). This composite approach combines the stripping capability of hydrofluoric acid with the corrosion-inhibiting properties of basic compounds and chelating agents, achieving both effective stripping and anticorrosion performance simultaneously.
2Object-affected harmful factors
If stripping solutions with strong corrosion resistance are used to protect SiO2 and metals, then anticorrosion properties are improved, but stripping effectiveness on photoresist and etching materials deteriorates
Solution Approach 1:
The patent changes the pH parameter to a basic range (pH 9-14), which fundamentally alters the chemical behavior of the stripping solution. At this basic pH, the solution maintains corrosion resistance while the basic compounds and chelating agents become effective at removing photoresist and etching materials, thus achieving both anticorrosion properties and stripping effectiveness simultaneously.
Solution Approach 2:
The composite formulation combines hydrofluoric acid (for stripping capability) with basic compounds (for pH control and corrosion resistance) and chelating agents (for enhanced stripping effectiveness). This composite approach ensures that the solution can strip materials effectively while the basic environment and chelating agents prevent corrosion of SiO2 and metals.
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 balances stripping properties with anticorrosion performance, preventing corrosion of SiO2 and metals, and can be continuously used for a longer period, ensuring reliable semiconductor manufacturing processes.
Implementation Method 1
containing (A) hydrofluoric acid, (B) a basic compound represented by the following general formula (b-1), and (C) water and having a pH at 23° C. of not more than 6.0 or 8.5 or more
Implementation Method 2
use of hydrofluoric acid and a compound containing ammonia as a counter amine thereof, hydrofluoric acid and a compound using 1,8-diazabicyclo[5.4.0]undecene-7 as a counter amine thereof
Data Source
AI summary
A stripping solution for photolithography which can effectively strip away residual materials of a photoresist pattern and etching residual materials, and has excellent anticorrosion properties on SiO2 and a variety of metal materials; and a method for forming a pattern using the stripping solution. A prescribed basic compound is used as a counter amine of the hydrofluoric acid contained in the stripping solution for photolithography, and the stripping solution for photolithography is adjusted to a pH measured at 23° C. of not more than 6.0 or 8.5 or more.