Cold Liquid Polishing Control for CMP Rate Management

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Solution Overview

Problem

Chemical mechanical polishing processes face challenges in controlling the polishing rate, particularly in transitioning from a high polishing rate in the bulk removal step to a low polishing rate in the clearing step, due to 'polishing rate momentum' and inefficiencies in existing cooling methods.

Innovation Solution

The implementation of a temperature control system that uses cold liquid DI water to rapidly reduce the polishing rate by spraying or flowing coolant directly onto the polishing pad, allowing for precise control of the polishing rate and eliminating the need for high-volume fluid usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cooling methods are used to reduce polishing rate, then polishing rate control is achieved, but large volumes of coolant fluid are consumed

Engineering Contradiction:

Improvepolishing rate controlVSAvoidcoolant fluid consumption

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The invention changes the temperature parameter of the coolant fluid from ambient temperature to sub-ambient temperature (cold coolant fluid). This parameter change enables rapid polishing rate reduction without requiring large volumes of coolant, thus resolving the contradiction between polishing rate control and coolant consumption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the conventional mechanical cooling method (large volume fluid flow) with a thermal cooling method (cold fluid at lower temperature). This substitution achieves the same cooling effect with significantly reduced fluid volume, addressing both polishing rate control and coolant conservation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If polishing rate is reduced from bulk removal to clearing step, then manufacturing precision is improved, but polishing rate momentum causes difficulty in control

Engineering Contradiction:

Improveclearing step precisionVSAvoidpolishing rate control

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention applies preliminary cooling action before transitioning to the clearing step. By reducing the polishing pad temperature in advance, the system counteracts the polishing rate momentum that would otherwise carry over into the clearing step, enabling precise control and high manufacturing precision

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system performs preliminary temperature reduction of the polishing pad before the clearing step begins. This preliminary action ensures that when the clearing step starts, the polishing rate is already reduced to the appropriate level, eliminating control difficulties caused by momentum

Inventive Principle:

Principle #10Preliminary action

3Productivity

If multiple sequential polishing steps are performed on the same platen, then productivity is increased, but polishing rate control between steps becomes difficult

Engineering Contradiction:

ImprovethroughputVSAvoidpolishing rate control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention uses temperature as a controllable parameter to reset the polishing rate between sequential steps. By adjusting the coolant temperature, the system can rapidly change the polishing rate to match the requirements of different polishing steps, enabling both high productivity and precise control on the same platen

Inventive Principle:

Principle #35Parameter changes

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 enables rapid and accurate control of the polishing rate, reducing the risk of dishing and erosion, conserving coolant fluid, and increasing throughput by allowing multiple sequential polishing steps on the same platen.

Implementation Method 1

spraying an aerosolized coolant liquid directly onto the polishing pad... flowing a stream of coolant liquid directly onto the polishing pad... to reduce a temperature of the polishing pad

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS20250114909A1Cold liquid polishing control

Publication Date: 2025.04.10 APPLIED MATERIALS INC

AI summary

A chemical mechanical polishing apparatus includes a platen to hold a polishing pad, a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process, a polishing liquid dispenser having a polishing liquid port positioned over the platen to deliver polishing liquid onto the polishing pad, a temperature control system including coolant liquid fluid reservoirs for containing coolant fluids, a thermal controller configured to control the temperature of the coolant fluid within the coolant fluid reservoirs, and a first dispenser having openings in fluid connection with the coolant fluid reservoirs, the openings positioned configured to spray an aerosolized coolant liquid directly onto the polishing pad, and a second dispenser having a coolant port in fluid connection with the coolant fluid reservoirs, the coolant port positioned over the platen and configured to flow a stream of coolant liquid directly onto the polishing pad.