IPA Vapor Filtration in Substrate Drying for 20 Nm Defect Control
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Solution Overview
Problem
Existing substrate drying technologies struggle to effectively suppress micro size defects (defects with a size of 20 nm or less) on substrates, particularly in semiconductor manufacturing, due to the presence of hydrophobic Low-k films and residues from CMP polishing, which can lead to water marks and particle-related issues.
Innovation Solution
A substrate drying device and method that utilizes a controlled supply of IPA vapor and rinse liquid, combined with a rotating mechanism, to manage drying gas concentration and flow rate across different areas of the substrate, ensuring the ratio of defect size to filter size is maintained at 4 or more, and stopping liquid supply at the edge to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drying methods are used with hydrophobic Low-k films, then drying can be performed, but water marks and micro size defects easily occur
Solution Approach 1:
The patent changes the physical and chemical parameters of the drying gas by controlling IPA concentration and temperature. The drying gas contains IPA vapor at concentrations of 1-50% by volume, and the substrate temperature is maintained at 40-80°C. These parameter changes modify the surface tension and evaporation characteristics of the rinse liquid, enabling effective drying of hydrophobic Low-k films without causing water marks or micro size defects
Solution Approach 2:
The patent utilizes phase transition of IPA from liquid to vapor. IPA liquid is heated to generate IPA vapor, which then mixes with carrier gas to form the drying gas. The IPA vapor condenses on the substrate surface and subsequently evaporates, controlling the drying process through these phase transitions to prevent defect formation
2Manufacturing precision
If substrate polishing is performed, then surface flatness is improved, but residues and foreign matters remain that cause reliability issues
Solution Approach 1:
The patent extracts and removes residues and foreign matters from the substrate surface through wet cleaning with rinse liquid followed by controlled drying. The drying process with IPA-containing gas extracts remaining water and contaminants from the surface, particularly from hard-to-clean areas, preventing adhesion defects and reliability issues
Solution Approach 2:
The patent uses IPA as an intermediary substance between the rinse liquid and the final dry state. IPA serves as a bridging fluid that mixes with water, reduces surface tension, and facilitates the removal of residues and foreign matters during the transition from wet cleaning to complete drying
3Productivity
If drying gas flow rate is increased to improve drying speed, then productivity increases, but micro size defects are more likely to occur
Solution Approach 1:
The patent optimizes the drying gas flow rate to a specific range that balances drying speed and defect prevention. The flow rate is controlled to provide sufficient drying action while avoiding excessive force that could cause micro size defects. This parameter optimization achieves both high productivity and high quality drying
Solution Approach 2:
The patent employs dynamic control of the drying process by adjusting gas flow rate and IPA concentration based on processing conditions. The system adapts the drying parameters to match the specific requirements of different substrates and contamination levels, maintaining optimal drying speed while preventing defect formation throughout the process
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 suppresses micro size defects by setting the defect size to 20 nm or less and optimizing gas concentration and flow rates, ensuring high-quality drying across the entire substrate surface.
Implementation Method 1
supplying a drying gas including IPA vapor to a substrate to move rinse liquid to an outer peripheral side with a Marangoni force
Implementation Method 2
supplying a drying gas including IPA vapor to a substrate to move rinse liquid to an outer peripheral side with a centrifugal force
Implementation Method 3
supplying a drying gas including IPA vapor to a substrate to dry the substrate
Data Source
AI summary
A substrate drying device is provided that can suppress occurrence of a micro size defect (for example, a defect having a defect size of 20 nm or less). A substrate drying device 1 includes a substrate holding unit 11 which holds a substrate W, a gas generator 60 which generates a drying gas G including at least IPA vapor and for drying the substrate W, and a drying gas nozzle 30 which supplies the drying gas G to the surface WA of the substrate W. A filter 67 for filtering the drying gas G is provided in the gas generator 60. A defect size D allowed in a defect test after the drying of the substrate W is set to 20 nm or less and a ratio D/F of the defect size D and a filter size F of the filter 67 is set to 4 or more.