Multi-Zone Etching Apparatus with Embedded End-Point Detectors

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Solution Overview

Problem

Single-site end-point detectors in etching processing chambers struggle to accurately detect etching rate non-uniformities, especially at larger wafer sizes like 450 mm, leading to inconsistent etching results due to the wafer loading effect.

Innovation Solution

An etching apparatus with multiple end-point detectors embedded in a gas distribution plate, each corresponding to different zones of the semiconductor workpiece, detects the spectral color of the etching plasma to determine etching degrees and end points, allowing for precise control of the etching process by adjusting gas flow rates and radio frequency power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-site end-point detector is used in the etching processing chamber, then the device complexity is reduced, but the measurement precision of etching rate non-uniformities deteriorates

Engineering Contradiction:

Improvedetector configurationVSAvoidetching rate detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The gas distribution plate is divided into multiple zones with separate gas supply channels, and multiple end-point detectors are distributed across different locations in the processing chamber. Each detector monitors etching plasma in its specific zone, enabling spatially-resolved measurement of etching rates across the wafer surface, thus resolving the contradiction between simple device structure and precise measurement capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The detection system transitions from a single-point measurement to multi-dimensional spatial measurement by distributing detectors across the processing chamber. This dimensional expansion allows simultaneous monitoring of etching rates at multiple locations, providing comprehensive measurement precision while maintaining manageable system complexity through modular detector placement

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the wafer size is increased to 450 mm, then the productivity is improved, but the manufacturing precision of etching uniformity deteriorates

Engineering Contradiction:

Improvewafer processing capacityVSAvoidetching uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The gas distribution plate is segmented into multiple zones with independent gas flow control, allowing targeted adjustment of etching conditions in different regions of large wafers. This zoned control enables uniform etching across the entire 450 mm wafer surface by compensating for local variations in plasma distribution and etching rate

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different zones of the gas distribution plate are equipped with independently controllable gas supply channels, enabling local optimization of etching parameters. Each zone can be adjusted to achieve optimal etching uniformity in its specific region, thereby maintaining high manufacturing precision across the entire large wafer surface

Inventive Principle:

Principle #3Local quality

3Measurement precision

If multiple end-point detectors are distributed across different zones, then the measurement precision of etching uniformity is improved, but the device complexity increases

Engineering Contradiction:

Improveetching uniformity detection accuracyVSAvoiddetector system configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple end-point detectors are integrated into a unified detection system with centralized signal processing and control. The detectors share common signal processing electronics and are coordinated through a single control system, which reduces the overall complexity compared to having completely independent detector systems while maintaining high measurement precision across all zones

Inventive Principle:

Principle #5Merging (Combining)

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 solution enables uniform etching across different zones of the semiconductor workpiece, improving etching precision and reducing the wafer loading effect, thereby achieving consistent etching results even at larger wafer sizes.

Implementation Method 1

detects the spectral color of the etching plasma to determine etching degrees and end points

Methodology Applied

Scientific EffectSpectral emission: Luminescence

Implementation Method 2

The gas distribution plate is configured to spurt gas into the processing chamber via a number of exhaust openings

Methodology Applied

Scientific EffectGas flow: Convection

Implementation Method 3

a radio frequency power element configured to provide the first electrode with radio frequency energy

Methodology Applied

Scientific EffectRadio frequency heating: Electromagnetic Induction

Data Source

PatentUS10515813B2Mechanisms for etching apparatus and etching-detection method

Publication Date: 2019.12.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Embodiments of mechanisms of an etching apparatus are provided. The etching apparatus includes a processing chamber. The etching apparatus also includes a gas distribution plate disposed in the processing chamber and comprising a number of exhaust openings. The etching apparatus further includes a number of end-point detectors disposed on the gas distribution plate. The gas distribution plate is configured to spurt gas into the processing chamber via the exhaust openings during a semiconductor process.