Liquid-Contact Nozzle Developing Method for Resist CD Uniformity
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Solution Overview
Problem
Conventional developing methods, such as the stationary and rotary developing methods, face challenges in achieving uniform critical dimension (CD) distribution in resist patterns due to convection issues and non-uniform developer flow, leading to longer processing times and inconsistencies.
Innovation Solution
A developing method utilizing a liquid-contact nozzle that supplies a developer to a rotating substrate, moving from the center toward the periphery, and a controlled boundary movement to terminate the developer reaction, combined with varying substrate rotational speeds and gas or liquid assistance to manage developer flow and drying, ensuring uniform CD distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stationary developing method is used, then the developer can react with the resist film, but the developing time becomes long due to lack of convection
Solution Approach 1:
The invention transitions from a stationary developing method to a dynamic method where the substrate rotates during development. This rotation creates convection currents in the developer solution, enhancing mass transport and reaction efficiency between the developer and resist film, thereby reducing developing time while maintaining reaction completeness.
Solution Approach 2:
The invention introduces a gas blowing mechanism that directs gas flow onto the developer solution during development. This pneumatic action generates convection and improves developer circulation over the resist film surface, accelerating the development reaction without compromising pattern fidelity.
2Productivity
If a rotary developing method is used, then the developing time is reduced, but the CD uniformity deteriorates due to non-uniform developer flow
Solution Approach 1:
The invention employs a gas blowing mechanism that creates localized convection patterns in the developer solution. By directing gas flow strategically, it ensures uniform developer distribution and circulation across different regions of the resist film, compensating for the non-uniform flow caused by substrate rotation and maintaining consistent CD throughout the pattern.
Solution Approach 2:
The invention implements a controlled gas blowing system that can be adjusted to optimize developer circulation. The gas flow rate and direction are controlled to maintain uniform developer coverage during rotation, providing a feedback mechanism that balances the centrifugal effects and ensures consistent development across the entire substrate surface.
3Speed
If the substrate rotates during development, then convection is enhanced, but the developer flow becomes non-uniform
Solution Approach 1:
The invention uses a gas blowing mechanism to counterbalance the non-uniform flow patterns caused by substrate rotation. The directed gas flow creates controlled convection currents that supplement the rotational convection, ensuring uniform developer circulation and preventing localized depletion or accumulation of developer solution.
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
This method significantly reduces the non-uniformity of CD distribution by controlling developer movement and reaction time, resulting in a more uniform resist pattern with improved processing efficiency.
Implementation Method 1
a developer is supplied onto a rotating substrate... The developer is ejected toward the substrate from an ejection orifice of a nozzle while moving the nozzle in the radial direction of the substrate... A liquid film of the developer is formed on a resist film by the action of centrifugal force due to the rotation of the substrate
Implementation Method 2
varying substrate rotational speeds and gas or liquid assistance to manage developer flow and drying
Data Source
AI summary
A developing method for forming a resist film having a high uniformity of CD distribution. After exposure of a resist film on a substrate surface to form a resist pattern, the method includes sequential steps of: (A) supplying a developer to the rotating substrate; (B) reacting the resist film with the developer; and (C) removing the developer from the surface of the resist film to terminate the reaction of the resist film with the developer. In step (A), a liquid-contact nozzle, having an ejection orifice for the developer and a lower surface extending laterally from the ejection orifice and disposed opposite the resist film, is used. In step (C), the boundary between a reaction-terminated area of the surface of the resist film, and an in-progress reaction area of the surface of the resist film, is moved from the center toward the periphery of the resist film.