CMP Retainer Ring Engraving for In-Situ Debris Removal

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Solution Overview

Problem

Conventional Chemical Mechanical Polishing (CMP) processes face issues with wafer scratch defects due to debris and abrasive particles accumulation on the polishing pad, leading to low yields and the need for offline manual removal, which is time-consuming and costly.

Innovation Solution

A CMP system with a retainer ring and conditioning disk featuring engraved regions that dislodge debris and abrasive particles during the polishing process, using vacuum systems to remove them in real-time, thereby conditioning the polishing pad in-situ and reducing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CMP process is used, then polishing can be performed, but wafer scratch defects occur due to debris and abrasive particles accumulation on the polishing pad

Engineering Contradiction:

Improvewafer surface qualityVSAvoiddebris and abrasive particles accumulation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The polishing pad conditions itself during the polishing process through the engraved regions on the retainer ring that dislodge accumulated debris and abrasive particles, eliminating the need for separate conditioning operations or external conditioning disks

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The harmful accumulated debris and abrasive particles are extracted from the polishing pad surface through the engraved regions of the retainer ring, which mechanically dislodge and remove these contaminants during polishing

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If offline manual removal of debris is performed, then polishing pad can be cleaned, but production time is lost and costs increase

Engineering Contradiction:

Improvepolishing pad cleanlinessVSAvoidproduction efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The polishing pad conditioning occurs continuously during the polishing process itself, with the engraved regions constantly dislodging debris as the pad rotates, rather than requiring intermittent offline cleaning stops

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The conditioning function is merged with the polishing operation, combining two previously separate processes (polishing and conditioning) into a single integrated operation that occurs simultaneously

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If external conditioning disks are used, then polishing pad can be conditioned, but device complexity and costs increase

Engineering Contradiction:

Improvepolishing pad conditioningVSAvoidconditioning system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The retainer ring serves multiple functions: it retains the polishing pad in place and simultaneously conditions the pad through its engraved regions, eliminating the need for separate conditioning disks or devices

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The polishing pad conditioning is performed by the retainer ring itself rather than requiring an external conditioning system, making the system self-sufficient and reducing overall complexity

Inventive Principle:

Principle #25Self-service

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 reduces defects caused by debris and abrasive particles, allowing for real-time polishing pad conditioning without the need for external conditioning disks, improving production efficiency and reducing costs.

Implementation Method 1

using vacuum systems to remove them in real-time

Methodology Applied

Scientific EffectVacuum suction: Suction

Implementation Method 2

A CMP system with a retainer ring and conditioning disk featuring engraved regions that dislodge debris and abrasive particles during the polishing process

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS20230278160A1Method and system for performing chemical mechanical polishing

Publication Date: 2023.09.07 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of using a polishing system includes securing a wafer in a carrier head, the carrier head including a housing enclosing the wafer, in which the housing includes a retainer ring recess and a retainer ring positioned in the retainer ring recess, the retainer ring surrounding the wafer, in which the retainer ring includes a main body portion and a bottom portion connected to the main body portion, and a bottom surface of the bottom portion includes at least one first engraved region and a first non-engraved region adjacent to the first engraved region; pressing the wafer against a polishing pad; and moving the carrier head or the polishing pad relative to the other.