Tracer-Based Spin Coating Control for Pattern Collapse Prevention

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Solution Overview

Problem

Conventional spin-on processes in semiconductor fabrication suffer from adverse local fluid dynamic effects that affect critical dimensions and pattern collapse on patterned substrates, due to uncontrolled local fluid dynamics during processing.

Innovation Solution

Introduce a tracer into the processing liquid dispensed onto a spinning semiconductor substrate, track its movement to determine localized fluid velocity, and use this information to control operational parameters such as rotational speed, flow rate, and nozzle position to mitigate these adverse effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If processing liquid is dispensed onto a spinning substrate at high flow rate, then coating speed is improved, but local fluid dynamic effects worsen causing pattern collapse

Engineering Contradiction:

Improvecoating speedVSAvoidpattern integrity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system measures localized fluid velocity using a tracer particle tracking system and feeds this information back to the controller, which adjusts operational parameters (rotational speed, flow rate, nozzle position) to maintain optimal fluid dynamics that prevent pattern collapse while preserving coating speed

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes operational parameters (rotational speed, flow rate, nozzle position) based on measured localized fluid velocity to optimize the balance between coating speed and pattern integrity, preventing adverse fluid dynamic effects

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If rotational speed is increased to improve coating uniformity, then coating quality is improved, but fluid velocity increases causing pattern collapse

Engineering Contradiction:

Improvecoating uniformityVSAvoidpattern collapse

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system measures localized fluid velocity and adjusts rotational speed dynamically to maintain optimal values that ensure coating uniformity while preventing pattern collapse caused by excessive fluid velocity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The tracer particle tracking system provides real-time feedback on fluid velocity, enabling the controller to adjust rotational speed to maintain the optimal balance between coating uniformity and pattern integrity

Inventive Principle:

Principle #23Feedback

3Productivity

If flow rate is increased to reduce processing time, then productivity is improved, but localized fluid velocity increases causing adverse effects

Engineering Contradiction:

Improveprocessing speedVSAvoidlocal fluid dynamic effects

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts flow rate based on measured localized fluid velocity to maintain optimal values that preserve productivity while preventing adverse fluid dynamic effects such as pattern collapse

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses tracer particle tracking to provide real-time feedback on fluid velocity, enabling dynamic adjustment of flow rate to optimize the balance between processing speed and pattern integrity

Inventive Principle:

Principle #23Feedback

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

Controls local fluid dynamics to prevent pattern collapse and maintain substrate performance by optimizing spin-on processes based on localized fluid velocity measurements.

Implementation Method 1

The spin chuck 110 and drive mechanism 115 are disposed within an opening in the cup 130. The spin chuck 110 supports and rotates (i.e., spins) the semiconductor substrate W about its central normal axis relative to the cup 130, which is stationary. As the spin chuck 110 rotates, the cup 130 captures and collects a majority of the processing liquid, which is ejected from the surface of the semiconductor substrate W by the centrifugal forces generated during rotation of the spin chuck 110.

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

an optical sensor configured to track movement of the tracer over time as the tracer flows along with the processing liquid at the unknown fluid velocity

Methodology Applied

Scientific EffectOptical detection:

Data Source

PatentUS12424467B2Systems and methods for determining a localized fluid velocity on a spinning substrate by tracking movement of a tracer across the spinning substrate

Publication Date: 2025.09.23 TOKYO ELECTRON LTD

AI summary

Systems and methods are provided to control operational parameter(s) of a spin-on process based on a localized fluid velocity of a processing liquid dispensed onto a surface of a spinning semiconductor substrate. In the present disclosure, a tracer is introduced within, or incorporated onto a surface of, a processing liquid as the processing liquid is dispensed onto the spinning semiconductor substrate. Movement of the tracer is tracked over time, as the tracer flows along with the processing liquid across the spinning substrate surface, to determine a localized fluid velocity of the processing liquid at one or more radial positions on the substrate surface. The localized fluid velocity is then used to control one or more operational parameters of a spin-on process.