Fluoroalkyl Amine Oxide Rinsing Liquid Prevents Microstructure Pattern Collapse
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Solution Overview
Problem
Current techniques fail to effectively suppress pattern collapse in microstructures, particularly those made of silicon oxide, such as semiconductor devices and micromachines, due to miniaturization and increased aspect ratios, despite efforts like using low-surface-tension rinsing liquids and hydrophobization.
Innovation Solution
A processing liquid containing a fluoroalkyl group-containing amine oxide compound and water is used to rinse microstructures, with the fluoroalkyl group adsorbing onto the silicon oxide surface, enhancing hydrophobicity and preventing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the resist pattern is miniaturized to reduce size and increase integration degree, then the device capabilities are improved, but pattern collapse occurs due to surface tension stress during drying
Solution Approach 1:
The invention changes the chemical composition parameters of the rinsing liquid by incorporating a fluorinated surfactant (specifically a fluorinated alkyl ether carboxylic acid or its salt), which has lower surface tension than conventional rinsing liquids. This parameter change in the liquid's surface tension reduces the surface tension stress applied to the miniaturized resist pattern during drying, thereby preventing pattern collapse while enabling continued miniaturization
Solution Approach 2:
The fluorinated surfactant acts as an intermediary substance between the rinsing liquid and the resist pattern. It adsorbs onto the resist pattern surface and forms a protective layer that reduces the direct impact of surface tension forces during drying. This intermediary mechanism allows the rinsing liquid to effectively wash away developer solution without causing pattern collapse in miniaturized structures
2Length of stationary object
If the aspect ratio of the resist pattern is increased to achieve higher device speed and integration, then device performance is improved, but pattern collapse becomes more severe
Solution Approach 1:
The invention changes the surface tension parameter of the rinsing liquid by adding fluorinated surfactant, which has significantly lower surface tension than water or conventional rinsing liquids. This parameter change reduces the capillary pressure and surface tension stress that would otherwise cause collapse of high aspect ratio structures during the drying process
Solution Approach 2:
The fluorinated surfactant is applied in advance during the rinsing step before drying occurs. It pre-coats the resist pattern surface and establishes a low surface tension environment that counteracts the upcoming surface tension stress during drying. This preliminary protective action prevents pattern collapse in high aspect ratio structures before the drying stress is applied
3Ease of manufacture
If conventional rinsing liquids are used to wash away developer solution, then cleaning is achieved, but pattern collapse occurs due to high surface tension stress
Solution Approach 1:
The invention modifies the physical-chemical parameters of the rinsing liquid by incorporating fluorinated surfactant, which reduces the liquid's surface tension from typical values (70-80 mN/m for water-based liquids) to lower values (30-50 mN/m). This parameter change maintains the rinsing liquid's ability to wet and remove developer solution effectively while simultaneously reducing the surface tension stress that causes pattern collapse during drying
Solution Approach 2:
The rinsing liquid is formulated as a composite system combining water or alcohol base with fluorinated surfactant additives. This composite composition integrates the cleaning effectiveness of conventional rinsing liquids with the low surface tension properties of fluorinated compounds, achieving both effective developer removal and pattern collapse prevention
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 proposed solution effectively suppresses pattern collapse in microstructures with high aspect ratios and fine patterns, maintaining structural integrity during the miniaturization process.
Implementation Method 1
the fluoroalkyl group adsorbing onto the silicon oxide surface, enhancing hydrophobicity and preventing pattern collapse
Implementation Method 2
the collapse of the resist pattern is caused by the stress derived by the surface tension of the processing liquid
Data Source
Figure 1~1(f)
AI summary
There are provided a processing liquid for suppressing pattern collapse of a microstructure formed of silicon oxide which includes at least one compound selected from the group consisting of a fluoroalkyl group-containing ammonium halide, a fluoroalkyl group-containing betaine compound and a fluoroalkyl group-containing amine oxide compound, and water; and a method for producing a microstructure formed of silicon oxide using the processing liquid.