Microdevice Test Electrodes for Hidden Contact Inspection

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Solution Overview

Problem

Existing microdevice inspection processes face challenges in accessing hidden contacts on microdevices, which hinders effective defect identification and performance analysis.

Innovation Solution

The method involves forming test electrodes to access both hidden and accessible contacts on microdevices, including vertical, flip chip, and lateral microdevices, by creating openings in dielectric layers and forming electrodes outside the microdevice.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If microdevice contacts are covered by dielectric layers for protection, then device reliability is improved, but access to hidden contacts for inspection becomes difficult

Engineering Contradiction:

Improvedevice reliabilityVSAvoidaccess to hidden contacts

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The dielectric layer is segmented by forming localized openings (via holes) that expose specific contact regions. This segmentation allows inspection electrodes to access hidden contacts while the remaining dielectric coverage maintains protection and reliability of other device regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Test electrodes are introduced as intermediary elements that bridge the inspection system and hidden contacts. These electrodes are formed through openings in the dielectric layer, enabling electrical access to hidden contacts without compromising the protective dielectric structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If openings are formed in dielectric layers to access hidden contacts, then inspection capability is improved, but device structure becomes more complex

Engineering Contradiction:

Improveinspection capabilityVSAvoiddevice structure

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The openings in the dielectric layer and the test electrodes are formed during the initial device fabrication process, before final packaging. This preliminary action integrates the inspection access structure into the manufacturing flow, avoiding additional post-processing steps and reducing overall structural complexity.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If multiple contacts are made accessible for comprehensive inspection, then measurement precision is improved, but manufacturing process becomes more complex

Engineering Contradiction:

Improvemeasurement precisionVSAvoidmanufacturing process

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The test electrode structure is designed with multi-functionality to handle various contact types (hidden and accessible contacts) through a unified approach. The same opening formation and electrode deposition process can access multiple different contacts, reducing the need for separate specialized structures for each contact type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250157861A1Cartridge for inspection

Publication Date: 2025.05.15 VUEREAL INC

AI summary

The present invention relates to the inspection process which includes providing access to the microdevice contacts, measuring the microdevice and analyzing the data to identify defects or performance of the micro device. The invention also relates to the forming of test electrodes on microdevices. The test electrodes may be connected to hidden contacts. The type of microdevices may be vertical, lateral or a flip chip.