Conductive Elastomer Probe for Oxide Film Inspection
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Solution Overview
Problem
Conventional methods for inspecting electrical characteristics of semiconductor devices at fine pitches are prone to damage, especially with oxide films, leading to defects and reduced durability due to direct contact and thermal expansion issues with rubber connectors.
Innovation Solution
An electrical characteristics inspection tool featuring a flexible sheet with a through electrode and conductive elastomer, allowing contact without direct probing, enabling inspection even with oxide films through the tunnel effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a probe card is used to directly contact pads or bumps for inspection, then electrical characteristics can be inspected, but the pad surface is scratched and oxide film is removed causing damage to fine-pitch semiconductor devices
Solution Approach 1:
The patent introduces a rubber connector with conductive particles as an intermediary between the inspection probe and the pad/bump. The rubber material provides cushioning to prevent scratching, while the conductive particles enable electrical contact through or through the oxide film without requiring its removal.
Solution Approach 2:
The patent changes the physical parameters of the contact interface by using a compliant rubber material instead of rigid probes. The rubber's elasticity and the conductive particles' properties allow the system to adapt to surface variations and penetrate oxide films without causing mechanical damage to the underlying pad or bump structures.
2Ease of operation
If rubber connectors with conductive particles are used for inspection, then contact can be made, but the conductive particles connect in the in-plane direction making it difficult to apply to fine pitches
Solution Approach 1:
The patent applies local quality by concentrating conductive properties at specific contact points within the rubber connector. The conductive particles are distributed throughout the rubber, but only those at the contact interface with the pad/bump become active, allowing fine-pitch applications while maintaining ease of contact.
3Strength
If a frame is provided to improve durability of rubber connectors, then structural strength is improved, but thermal expansion causes positional deviation leading to inspection failure
Solution Approach 1:
The patent addresses thermal expansion by changing the material parameters of the rubber connector to have low thermal expansion characteristics. This allows the connector to maintain its mechanical strength and durability while minimizing positional deviation during heat cycle tests, thereby maintaining inspection accuracy.
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 tool effectively inspects electrical characteristics without damaging fine-pitch pads or bumps, maintaining durability and reducing defects, as the conductive elastomer breaks through or tunnels through the oxide film, improving inspection reliability and yield.
Implementation Method 1
enabling inspection even with oxide films through the tunnel effect
Implementation Method 2
the conductive elastomer breaks through or tunnels through the oxide film
Data Source
AI summary
An electrical characteristics inspection tool capable of inspecting electrical characteristics even when an oxide film is formed on pads or bumps formed at a fine pitch. The electrical characteristics inspection tool includes: a flexible sheet; a through electrode having a recess that is recessed from one surface of the flexible sheet; and a conductive elastomer disposed in the recess of the through electrode. Electrical characteristics can be inspected even when an oxide film is formed on pads or bumps of an inspection object by bringing the conductive elastomer into contact with the pads or bumps and bringing a probe into contact with the through electrode since the conductive particles in the conductive elastomer break through the oxide film.