Resist Buffer Tank Geometry for Continuous Flow Defect Reduction

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Solution Overview

Problem

The existing lithography processes face challenges in maintaining a defect-free photoresist material, particularly due to crystallization defects that occur when the resist material remains stationary in the pump system, leading to non-uniformity in the layout patterns and critical dimension (CD) issues during the fabrication of integrated circuits.

Innovation Solution

A resist pump system is designed to maintain continuous flow and circulation of the resist material from the supply to the dispensing nozzle, utilizing a resist tank structure with a specific geometry and adjustable valves to prevent crystallization, ensuring the material does not stay stationary and is filtered to remove defects, thereby ensuring a steady and laminar flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resist material is kept stationary in the pump system, then the system operation is simplified, but the resist material crystallizes and creates defects

Engineering Contradiction:

Improvedefect-free resist materialVSAvoidpump system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The resist material is kept in continuous circulation through the pump system rather than being stationary. The pump continuously circulates the resist material through the system, ensuring it never stops moving, which prevents crystallization and maintains defect-free resist material throughout the coating process.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system transitions from a static resist material state to a dynamic circulating state. The pump system creates continuous motion of the resist material through controlled flow cycles, making the previously stationary resist material dynamic to prevent crystallization.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the resist material flows continuously through the pump system, then crystallization is prevented, but the flow may become non-uniform causing defects

Engineering Contradiction:

Improvecrystallization preventionVSAvoidflow uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The pump system operates with periodic flow cycles, alternating between different flow rates or directions in a controlled manner. This periodic action maintains continuous motion to prevent crystallization while the controlled variation ensures uniform flow characteristics that avoid defects.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system monitors resist material flow characteristics and adjusts pump operation accordingly. Sensors detect flow uniformity and provide feedback to the control system, which modifies pump parameters to maintain optimal flow conditions that prevent both crystallization and flow-induced defects.

Inventive Principle:

Principle #23Feedback

3Productivity

If the resist material stays in the pump system for extended periods, then batch processing efficiency improves, but defects accumulate over time

Engineering Contradiction:

Improvebatch processing efficiencyVSAvoidresist material quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The resist material undergoes continuous circulation and renewal throughout the batch processing period. The pump system ensures the resist material is constantly moved and refreshed, preventing defect accumulation even during extended processing times, thereby maintaining high productivity with sustained material quality.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system periodically refreshes the resist material by introducing fresh material and removing used material that has been in the system for extended periods. This renewal process prevents defect accumulation while maintaining continuous operation for high productivity batch processing.

Inventive Principle:

Principle #34Discarding and recovering

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 approach significantly reduces the number of defects in the resist material, maintaining the integrity of the photoresist layer and ensuring uniformity in the layout patterns, thus enhancing the yield and quality of integrated circuit fabrication.

Implementation Method 1

utilizing a resist tank structure with a specific geometry and adjustable valves to ensure a steady, laminar flow that avoids crystallization

Methodology Applied

Scientific EffectLaminar flow: Laminar Flow

Implementation Method 2

A resist pump system is designed to maintain continuous flow and circulation of the resist material, preventing it from staying stationary

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11835861B2Resist pump buffer tank and method of resist defect reduction

Publication Date: 2023.12.05 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A resist material dispensing system includes a resist supply and a resist filter connected to the resist supply downstream from the resist supply. The resist material dispensing system includes a resist tank structure connected to the resist filter downstream from the resist filter and a resist pump device connected to the resist tank structure downstream from the resist tank structure. The resist tank structure is vertically arranged so that a resist material flows in a continuous downward flow from where the resist material enters the resist tank structure until the resist material exits the resist tank structure.