Wafer Inspection Bridge Module Shortens Test Loop Path

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Solution Overview

Problem

Conventional wafer probing systems experience signal distortion and inaccuracy due to long conduction paths in test loops, especially when using short-pulse, high-current signals, leading to inspection inaccuracies and failures.

Innovation Solution

A wafer inspection system comprising a susceptor device, a probe card, and a bridge module that creates a shorter test loop by coupling the probe card's conducting portion directly to transmission units positioned adjacent to the wafer placement area, reducing the path length and enhancing signal accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cable is used to connect the probe card and the carrier, then the test loop is established, but the conduction path becomes long causing signal distortion and waveform deformation

Engineering Contradiction:

Improvetest signal qualityVSAvoidconduction path length

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The invention extracts and eliminates the cable from the test loop, replacing it with direct contact between the probe card's conducting portion and the carrier. This removes the harmful element (cable) that causes signal distortion while maintaining the essential function of electrical connection.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the probe card's conducting portion directly with the carrier by bringing them into contact, eliminating the intermediate cable connection. This integration shortens the conduction path and improves signal integrity by combining previously separate components into a unified electrical pathway.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If the conduction path is lengthened to accommodate cable connections, then the test loop can be established, but the induction effect increases causing severe waveform distortion

Engineering Contradiction:

Improvetest loop establishmentVSAvoidinduction effect

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful induction effect into a benefit by minimizing the conduction path length. By eliminating the cable and using direct contact, the path is shortened to the minimum necessary length, thereby reducing induction effects and waveform distortion while maintaining test loop functionality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a long cable path is used for connection, then the test loop is formed, but the material effects on signal transmission increase leading to inspection inaccuracy

Engineering Contradiction:

Improveinspection accuracyVSAvoidsignal degradation

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention extracts and removes the cable from the signal path, eliminating the material that causes signal degradation. By using direct contact between the probe card's conducting portion and the carrier, the harmful material intermediary is removed, preserving signal integrity and improving inspection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution effectively shortens the test loop path, reduces waveform distortion, and improves the accuracy of wafer inspections by ensuring precise signal transmission and reception through the bridge module and conductive layers.

Implementation Method 1

a test signal outputted by the probe card passes through the wafer under test, propagates from the bottom surface thereof to the susceptor unit, and returns to the probe card via at least one of the transmission units and the conducting portion, thereby forming a test loop

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11609261B2Wafer inspection system and wafer inspection equipment thereof

Publication Date: 2023.03.21 CHROMA ATE INC

AI summary

A wafer inspection system and a wafer inspection equipment thereof are provided. The wafer inspection system includes a susceptor device, probe card, and bridge module. The susceptor device includes a susceptor unit for placing a wafer under test. The probe card includes a probing portion and conducting portion. The conducting portion is disposed at the periphery of the probing portion and has a contact surface. The bridge module includes transmission units extended upward, positioned adjacent to a wafer placement area, and coupled to the susceptor unit. When the probing portion comes into contact with a testing point of the wafer, the contact surface of the conducting portion gets coupled to the transmission units to transmit a test signal to the probe card via the transmission units and conducting portion and thus form a test loop. Thus, the test loop path can be shortened and the accuracy of signal transmission and inspection can be enhanced.