Electron Beam Testing of Packaging Substrates Without Pad Contact
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Solution Overview
Problem
Existing methods for testing complex packaging substrates, such as panel-level and advanced packaging substrates, face challenges with miniaturization, increased complexity, and topography, leading to difficulties in reliable and efficient detection of defects like shorts, opens, and leakages, especially with mechanical and capacitive detectors.
Innovation Solution
A contactless testing method using electron beams to direct and scan electron beams on packaging substrates, combined with UV radiation, for detecting signal electrons to identify and characterize defects, allowing for precise charging and discharging of surface contact points without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact probes are used to test contact pads, then electrical connection can be established for testing, but the risk of damaging the device under test increases and contacting reliability decreases due to miniaturization
Solution Approach 1:
The patent replaces mechanical contact probes with a non-contact testing method using electron beams and capacitive detectors. The electron beam is directed at the contact pads to induce charge, and the resulting electrical fields are detected capacitively without physical contact, thereby eliminating mechanical damage risks while maintaining testing capability
Solution Approach 2:
The patent introduces electron beams as an intermediary to establish electrical connection for testing. Instead of direct mechanical contact, the electron beam induces charge on the contact pads, creating an electrical field that can be detected capacitively, serving as a non-contact intermediary for electrical testing
2Reliability
If the number of test points increases to handle complex packaging substrates, then more defects can be detected, but throughput decreases
Solution Approach 1:
The patent implements continuous scanning of electron beams across multiple contact pads simultaneously, maintaining continuous testing action rather than sequential point-by-point testing. This allows high-volume defect detection across complex substrates while maintaining high throughput through parallel processing capability
Solution Approach 2:
The testing apparatus is designed with multi-functional capability to handle various contact pad configurations and substrate types universally. The electron beam system can rapidly adapt to different test point arrangements, enabling comprehensive defect detection across complex packaging substrates without requiring specialized equipment for each configuration
3Measurement precision
If mechanical spacing is reduced for capacitive detectors to improve sensitivity, then detection precision improves, but the topography of packaging substrates creates difficulties
Solution Approach 1:
The patent replaces mechanical capacitive detectors requiring close physical spacing with electron beam-based testing. The electron beam can detect electrical fields through vacuum space without mechanical contact, eliminating topography constraints while maintaining high detection precision through electronic field sensing
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 reliable and efficient detection of defects in packaging substrates with high throughput, avoiding damage to small contact pads and overcoming topographical challenges, while maintaining accuracy and speed.
Implementation Method 1
directing at least one electron beam of the at least one electron beam column on at least a first portion of the packaging substrate; directing the at least one electron beam of the at least one electron beam column on at least a second portion of the packaging substrate; detecting signal electrons emitted upon impingement of the at least one electron beam
Implementation Method 2
illuminating at least a third portion of the packaging substrate with UV radiation
Data Source
AI summary
A method for testing a packaging substrate with at least one electron beam column is described, wherein the packaging substrate is a panel level packaging substrate or an advanced packaging substrate. The method includes placing the packaging substrate on a stage in a vacuum chamber; directing at least one electron beam of the at least one electron beam column on at least a first portion of the packaging substrate; directing the at least one electron beam of the at least one electron beam column on at least a second portion of the packaging substrate; detecting signal electrons emitted upon impingement of the at least one electron beam for testing a first device-to-device electrical interconnect path of the packaging substrate; and illuminating at least a third portion of the packaging substrate with UV radiation.