Floating Electrical Barrier for Integrated Circuit Dendritic Migration
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Solution Overview
Problem
Dendritic migration between electrodes in integrated circuit packages can lead to short circuit failures due to the migration of species like silver under voltage differential and moisture conditions, particularly in non-hermetic packages.
Innovation Solution
A floating electrical barrier, such as a dam made of nickel, is mounted on the support substrate between the electrodes to prevent metal migration, with a height equal to or greater than the largest dimension of the migratory species and fabricated using screen printing techniques, effectively stopping the migration of silver atoms by requiring a higher energy level for further ionization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-hermetic integrated circuit package is used, then manufacturing cost and ease of manufacture are improved, but dendritic migration occurs leading to short circuit failure
Solution Approach 1:
An electrical barrier is introduced as an intermediary element between the first and second electrodes. This barrier physically interrupts the migration path of dendritic growth caused by silver ion migration under voltage differential, preventing short circuit failure while maintaining the non-hermetic package structure
Solution Approach 2:
The electrical barrier segments the continuous migration path between electrodes into separate regions. By placing the barrier at a strategic location, the potential dendritic bridge is divided into disconnected segments, preventing complete short circuit formation
2Reliability
If the migratory species is removed from electrodes, then dendritic migration is prevented improving reliability, but manufacturing complexity and cost increase
Solution Approach 1:
Rather than removing the migratory species (silver) from the electrodes which would require changing electrode materials, an electrical barrier is placed between the electrodes to intercept and block the silver ion migration path, achieving reliability improvement without modifying the electrode composition
Solution Approach 2:
The electrical barrier is pre-positioned between the electrodes during manufacturing to prevent dendritic migration before it can occur. This preliminary protective measure eliminates the need to alter electrode materials or remove migratory species
3Ease of manufacture
If air cavities are present in non-hermetic packages, then ease of manufacture is improved, but dendritic migration is promoted reducing reliability
Solution Approach 1:
The electrical barrier serves as a mediator that blocks the harmful dendritic migration effect within the air cavity environment. The barrier is positioned to intercept silver ion migration paths that would otherwise utilize the air cavity space to bridge electrodes
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 electrical barrier effectively prevents short circuits by arresting silver dendrites at the barrier, ensuring the electrical characteristics of the electrodes remain unchanged and maintaining circuit functionality.
Implementation Method 1
effectively stopping the migration of silver atoms by requiring a higher energy level for further ionization
Implementation Method 2
a floating electrical barrier, which includes a dam mounted to the support substrate. The dam is located between the first electrode and the second electrode in a position to prevent metal migration
Data Source
AI summary
In a general aspect, an integrated circuit package includes a first electrode and a second electrode on a support substrate. The first electrode and the second electrode are configured to be electrically coupled to a voltage differential. A dendritic migration of a migratory species can develop under the voltage differential and a non-hermetic environment. The dendritic migration is interrupted by a floating electrical barrier mounted onto the support substrate between the first electrode and the second electrode. The electrical barrier includes a dam for preventing the metal migration. The dam has a height approximately equal to or greater than the largest dimension of a single atom of the migratory species. The first electrode and the second electrode can be mounted on the same side of the support substrate, or on two opposite sides of the support substrate.