CMP Ion Removal Using Capacitive Deionization Modules

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Solution Overview

Problem

The semiconductor industry faces challenges in reducing ion deposition during chemical mechanical planarization (CMP) processes, which leads to defects such as humps on the surface of semiconductor devices, affecting device performance and yield.

Innovation Solution

Incorporating capacitive deionization modules (CDMs) into the CMP system to remove ions from solutions used in the CMP process, including flow-by and flow-through configurations, operating in constant voltage or constant current modes, to prevent ion deposition on substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CMP process is used, then planarization is achieved, but ion deposition occurs causing surface defects

Engineering Contradiction:

Improvesurface flatnessVSAvoidion deposition

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The capacitive deionization module removes ions from the CMP slurry before the slurry contacts the substrate surface. This preliminary ion removal prevents ion deposition and subsequent hump formation, allowing the CMP process to achieve both planarization and defect-free surfaces.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The capacitive deionization module acts as an intermediary between the CMP slurry and the substrate. It selectively removes harmful ions from the slurry while allowing the beneficial polishing particles and chemicals to remain, thus mediating the interaction to prevent harmful ion deposition while maintaining effective planarization.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If ion removal is implemented during CMP, then ion deposition is reduced, but process complexity increases

Engineering Contradiction:

Improveion depositionVSAvoidCMP system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces mechanical ion removal methods with an electrical field-based capacitive deionization approach. The capacitor plates create an electrical field that selectively attracts and removes ions from the slurry without requiring complex mechanical filtration or chemical treatment systems, thus reducing overall process complexity while effectively preventing ion deposition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 use of CDMs in the CMP system effectively reduces ion deposition, enhancing semiconductor device performance and yield by preventing defects like humps, thereby improving the overall manufacturing process.

Implementation Method 1

Incorporating capacitive deionization modules (CDMs) into the CMP system to remove ions from solutions used in the CMP process

Methodology Applied

Scientific EffectCapacitive deionization: Capacitance

Data Source

PatentUS11984323B2CMP system and method of use

Publication Date: 2024.05.14 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A chemical mechanical planarization (CMP) system including a capacitive deionization module (CDM) for removing ions from a solution and a method for using the same are disclosed. In an embodiment, an apparatus includes a planarization unit for planarizing a wafer; a cleaning unit for cleaning the wafer; a wafer transportation unit for transporting the wafer between the planarization unit and the cleaning unit; and a capacitive deionization module for removing ions from a solution used in at least one of the planarization unit or the cleaning unit.