Etching Depth Measurement via Mass Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing ion beam etching apparatuses face challenges in accurately measuring etching depth due to particle accumulation on the polarization window, leading to reduced accuracy and difficulty in long-term stable measurement.

Innovation Solution

An etching depth measuring device that uses a chamber with an introduction port for active species, a mass detecting element to receive and detect substances generated during etching, and an energy adjusting section to control the ion beam's energy, allowing for real-time etching depth calculation without laser interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser beam is used to measure etching depth through polarization window, then continuous measurement is possible, but particles accumulate on the polarization window blocking the laser beam and reducing measurement accuracy

Engineering Contradiction:

Improveetching depth measurement accuracyVSAvoidlong-term stable measurement

Core Design Contradiction:

Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The invention extracts the measurement function from the main etching chamber by introducing a separate member to be processed into a dedicated measurement chamber. This separation removes the source of particle contamination from the measurement path, allowing continuous laser-based polarization measurement without window fouling. The member to be processed is transferred between etching and measurement chambers, enabling independent operation of measurement that doesn't suffer from particles generated during etching.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a member to be processed as an intermediary medium to transfer etching depth information. Instead of measuring particles directly from the object, the method etches a reference member with known properties and measures its depth change through polarization. This intermediary approach allows indirect measurement that avoids direct exposure to the harsh etching environment while maintaining measurement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If correlation between etching time and etching depth is used to predict depth, then measurement is simple, but accuracy is insufficient for precise control

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidetching depth accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces the indirect time-correlation method with direct optical measurement using laser polarization. Instead of inferring depth from etching duration and rate assumptions, the system directly measures the physical depth change by detecting polarization state changes of laser light reflected from the member surface. This substitution provides real-time, accurate depth measurement while maintaining operational simplicity through automated detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the same ion beam is used for both etching the object and measurement, then the system is simple, but measurement accuracy deteriorates due to particle accumulation

Engineering Contradiction:

Improvesystem structureVSAvoidetching depth measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The invention segments the ion beam system into separate functional zones: a main etching chamber for processing the object and a separate measurement chamber for depth measurement. The ion beam is introduced independently into each chamber, allowing the measurement chamber to operate without particle contamination from the object etching process. This spatial segmentation enables both functions to operate simultaneously with high precision without mutual interference.

Inventive Principle:

Principle #1Segmentation

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

Enables stable and accurate long-term measurement of etching depth by correlating detected mass with etching depth, avoiding the limitations of particle accumulation and improving measurement precision compared to conventional methods.

Implementation Method 1

a mass detecting element which receives a substance generated from the member to be processed and detects mass of the received substance

Methodology Applied

Scientific EffectMass spectrometry:

Implementation Method 2

the mass detecting element comprise a member in which the resonance frequency changes in response to a change in the mass of the received substance

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

etching the object to be processed by using active species present in a plasma

Methodology Applied

Scientific EffectPlasma etching: Plasma

Data Source

PatentUS7794563B2Etching depth measuring device, etching apparatus, and etching depth measuring method

Publication Date: 2010.09.14 TDK CORP

AI summary

An etching depth measuring device for measuring the etching depth of an object to be processed, when etching the object to be processed by using active species present in a plasma, the etching depth measuring device comprising: a chamber in which is formed an introduction port for introducing a part of the active species; a member to be processed which is housed in the chamber and etched by the part of the active species; and a mass detecting element which receives a substance generated from the member to be processed and detects the mass of the received substance.