Wafer Bonding Strength Measurement via Crack and Water Mist Detection

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Solution Overview

Problem

Current methods for measuring wafer bonding strength in low-temperature direct bonding technology are destructive, leading to high wafer scrap rates and accuracy issues due to the use of blade insertion methods.

Innovation Solution

A non-destructive method involving pressure and tension application to create a crack in the bonded wafers, followed by water mist penetration and measurement using infrared or ultrasonic detection to calculate bonding strength without damaging the wafers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If blade insertion method is used to measure bonding strength, then measurement can be performed, but wafer is damaged and scrap rate increases

Engineering Contradiction:

Improvebonding strength measurementVSAvoidwafer damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical blade insertion system with an optical measurement system. Instead of using a physical blade to create and measure cracks, the invention uses optical fields (laser or other light sources) to detect crack propagation and measure bonding strength, thereby eliminating mechanical damage to the wafer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an optical field as an intermediary between the measurement objective and the wafer. The optical field interacts with the crack to provide measurement information without physically contacting or damaging the wafer, serving as a non-contact mediator for the measurement process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If blade insertion method is used, then bonding strength can be measured, but measurement accuracy decreases due to blade thickness and insertion speed variations

Engineering Contradiction:

Improvebonding strength measurementVSAvoidmeasurement consistency

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent eliminates the mechanical blade system entirely and replaces it with an optical measurement system. This substitution removes the sources of variability associated with blade thickness, material properties, and insertion speed, providing consistent and repeatable measurements without mechanical intervention.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If destructive measurement methods are used, then bonding strength can be assessed, but wafer cost increases due to high scrap rate

Engineering Contradiction:

Improvebonding strength assessmentVSAvoidwafer scrap

Core Design Contradiction:

Measurement precisionVSLoss of substance

Solution Approach 1:

The patent uses optical fields instead of mechanical blade insertion to measure bonding strength. This non-contact optical method allows measurement without creating irreversible damage, enabling the wafer to remain usable after measurement and thereby reducing scrap and associated costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical measurement system allows the wafer to serve itself for measurement purposes without requiring destructive intervention. The wafer's own optical properties and crack behavior are utilized for measurement, eliminating the need for external mechanical tools that cause damage.

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

Accurately measures bonding strength without destroying the wafers, reducing scrap rates and measurement errors, and providing cost-effective results.

Implementation Method 1

said first wafer is fixed to the surface of the working platform by vacuum adsorption, that is, pores are distributed on the surface of the working platform, and said first wafer is adsorbed on the surface of the working platform by forming a vacuum or negative pressure at the pores

Methodology Applied

Scientific EffectVacuum adsorption: Vacuum

Implementation Method 2

spraying water mist into the crack to allow the water mist to penetrate into the crack

Methodology Applied

Scientific EffectFluid spray: Fluid Spray

Implementation Method 3

measuring the size of the crack and calculating the bonding strength of the wafer... the size of the crack is measured by infrared detection or ultrasonic detection

Methodology Applied

Scientific EffectInfrared detection: Infrared Radiation

Implementation Method 4

measuring the size of the crack and calculating the bonding strength of the wafer... the size of the crack is measured by infrared detection or ultrasonic detection

Methodology Applied

Scientific EffectUltrasonic detection: Ultrasound

Data Source

PatentUS20260043726A1Method for non-destructive measurement of wafer bonding strength

Publication Date: 2026.02.12 DONGGUAN ATTACH POINT INTELLIGENT EQUIP CO LTD

AI summary

The method for non-destructively measuring the bonding strength of wafers comprises the following steps: Step 1: placing two wafers that have been bonded on a working platform, wherein the first wafer located at the bottom is fixed to the surface of the working platform; Step 2: applying pressure and tension to the second wafer located at the top at different regions thereof at the same time; Step 3: a crack is generated between the second wafer and the first wafer under the pressure and tension; Step 4: after the crack is formed, spraying water mist into the crack to allow the water mist to penetrate into the crack; Step 5: measuring the size of the crack and calculating the bonding strength of the wafer according to the following formula: γ=3Et3y2/32L4.