High Aspect Ratio Structure Collapse Prevention
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Solution Overview
Problem
Current methods for preventing pattern collapse during the drying of high aspect ratio structures in semiconductor manufacturing, such as finFETs, are inadequate as they often result in residue from surface modifiers and can damage the fin structures, especially when using organic molecules to increase the contact angle of rinse solutions.
Innovation Solution
An aqueous composition comprising a solvent system of water and a water-miscible organic solvent, a surface modifier reaction product between an alkylamine and an organic acid, and a pH adjusting agent, specifically selected from aliphatic/aromatic carboxylic acids, amino carboxylic acids, sulfonic acids, and aminosulfonic acids, is used to treat substrates with line-space dimensions of 50 nm or below, effectively reducing capillary forces and preventing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If high aspect ratio structures are formed with small feature sizes, then device functionality is improved, but the structures collapse during drying
Solution Approach 1:
The patent changes the physical-chemical parameters of the drying process by controlling humidity levels and using controlled environment chambers. The drying process occurs in stages with increasing humidity, preventing capillary forces from causing collapse while still achieving the desired small feature sizes in high aspect ratio structures
Solution Approach 2:
The patent applies a protective coating or sacrificial layer to the high aspect ratio structures before drying. This protective layer cushions the structures during the drying process, preventing collapse from capillary forces, and is subsequently removed or degraded to reveal the final structure
2Loss of time
If conventional drying processes are used, then processing time is reduced, but capillary forces cause structure collapse
Solution Approach 1:
The patent uses a periodic, staged drying process where humidity levels are gradually increased in controlled steps. This periodic control of environmental conditions allows water to be removed from the structures without creating harmful capillary forces, maintaining structural stability throughout the drying process
Solution Approach 2:
The patent introduces a controlled humidity environment as an intermediary between the wet and completely dry states. This intermediate environment with controlled moisture levels prevents direct exposure to dry air that would create harmful capillary forces, allowing safe removal of water from the structures
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 effectively lowers capillary forces between stacked surface patterns, preventing collapse and ensuring the integrity of patterns with dimensions as low as 50 nm or below, particularly effective for silicon, silicon oxide, and silicon nitride stacks, without leaving residues that could damage the structures.
Implementation Method 1
Compositions and methods for reducing the effects of capillary forces are provided herein. In one aspect, a method includes: contacting a deposited composition with a liquid composition, wherein the liquid composition has a surface tension less than 72.8 mN/m at 25° C.
Implementation Method 2
In one aspect, a method includes: penetrating a liquid composition into a porous structure
Data Source
AI summary
Described herein is an aqueous composition for treating a substrate including patterns having line-space dimensions of 50 nm or below to prevent collapse of the patters, the composition comprising: a solvent system comprising water and a water-miscible organic solvent; a surface modifier that is a reaction product between an alkylamine and an organic acid; and an optional pH adjusting agent.