Slurry Feed System Surface Tension Control for CMP Yield

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The surface tension of the slurry in chemical mechanical planarization (CMP) processes in semiconductor fabrication facilities is critical, and excessive surface tension leads to pit defects on silicon wafers, necessitating effective monitoring and control to maintain optimal CMP yields.

Innovation Solution

A slurry feed system that includes a surface tension meter coupled to the slurry supply loop, a programmable logic controller to adjust the slurry feed pump rate based on measured surface tension, and redundant supply loops to ensure consistent slurry quality and prevent defects, with features like mixing and recirculation loops to maintain uniform composition and prevent foam formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If slurry is supplied to CMP station without surface tension control, then CMP process can proceed, but pit defects occur on silicon wafers

Engineering Contradiction:

ImproveCMP yieldVSAvoidpit defects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system employs a surface tension meter to continuously monitor slurry surface tension and provides feedback to a programmable logic controller. The controller automatically adjusts the slurry feed pump rate based on this feedback, maintaining surface tension within the optimal range of 20-30 dynes/cm to prevent pit defects and ensure high CMP yield.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the flow rate parameter of slurry supply based on measured surface tension values. When surface tension exceeds the optimal range, the system increases flow rate to dilute the slurry and reduce surface tension, thereby preventing defect formation while maintaining process reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If slurry feed rate is increased to maintain flow, then surface tension control becomes difficult, but if feed rate is decreased, then CMP productivity drops

Engineering Contradiction:

Improvesurface tension controlVSAvoidCMP throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the slurry feed rate based on real-time surface tension measurements rather than operating at a fixed rate. The programmable logic controller continuously modulates the pump speed to maintain surface tension within the optimal range, allowing the system to adapt to changing conditions while maintaining both quality and productivity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the flow rate parameter dynamically in response to surface tension measurements. By adjusting this critical parameter based on feedback, the system maintains optimal surface tension control without sacrificing CMP throughput, as the adjustments are made only when necessary to maintain quality parameters.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If slurry is stored without recirculation, then system is simpler, but slurry composition becomes non-uniform and foam forms

Engineering Contradiction:

Improveslurry system structureVSAvoidslurry uniformity

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The system implements continuous recirculation of slurry through the storage tank, ensuring that the slurry composition remains uniform and foam is prevented throughout operation. This continuous motion prevents settling and maintains consistency without requiring complex additional components beyond the recirculation pump and piping.

Inventive Principle:

Principle #20Continuity of useful action

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 system effectively monitors and controls surface tension, preventing defects by adjusting flow rates and ensuring consistent slurry quality, thereby enhancing CMP process yields and maintaining optimal surface tension within acceptable ranges.

Implementation Method 1

the surface tension of the slurry in chemical mechanical planarization (CMP) processes in semiconductor fabrication facilities is critical

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Implementation Method 2

features like mixing and recirculation loops to maintain uniform composition

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

recirculation loops to maintain uniform composition and prevent foam formation

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS10814455B2Slurry feed system and method of providing slurry to chemical mechanical planarization station

Publication Date: 2020.10.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Disclosed herein is a method of providing slurry to a chemical mechanical planarization (CMP) station. The method includes the operations of: mixing slurry, water and a chemical to form dilute slurry; measuring a surface tension of the dilute slurry; supplying the dilute slurry to a CMP station through piping; and modulating a flow rate of the dilute slurry in the piping in accordance with the measured surface tension.