Shielded Die Bonding Structure for Ion Migration Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion migration in bonding materials used in communications devices, such as power amplifiers, leads to electrode damage and reliability issues due to the high-temperature and high-humidity environments, where ions combine with charged electrodes causing short-circuits.
Innovation Solution
A package structure with a shielding structure that alters the electric field distribution between the bonding layer and the electrode, preventing charged particles from migrating to the electrode by connecting the shielding structure to a zero or specific potential, thereby blocking ion migration without adding elements or compounds to the bonding material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a material with good thermal conductivity (such as gold-tin alloy or sintered silver) is used as bonding material, then heat dissipation is improved, but ion migration occurs causing electrode damage and reliability degradation
Solution Approach 1:
A shielding layer is introduced as an intermediary structure between the bonding material and the electrode. This shielding layer mediates the interaction by blocking ion migration paths while maintaining thermal conductivity through the bonding material. The shielding layer acts as a protective barrier that prevents direct contact between migrating ions and the electrode, thus resolving the contradiction between heat dissipation and electrode reliability
Solution Approach 2:
The structure is segmented into distinct functional layers: the bonding material layer for thermal management, the shielding layer for ion migration prevention, and the electrode layer for electrical function. This segmentation allows each layer to optimize its specific function without interfering with others, enabling simultaneous achievement of good heat dissipation and electrode protection
2Reliability
If elements or compounds are added to the bonding material to block ion migration, then electrode protection is improved, but the bonding material complexity increases and may cause blocking failure over time
Solution Approach 1:
Instead of modifying the bonding material composition, the patent segments the structure by introducing a separate shielding layer. This keeps the bonding material simple and unchanged while providing ion migration blocking functionality through the dedicated shielding layer, thus avoiding the complexity and long-term reliability issues of modified bonding materials
Solution Approach 2:
The shielding layer serves as an intermediary structure that provides ion migration blocking without requiring modification of the bonding material. This separate intermediary approach maintains the simplicity and proven performance of the original bonding material while adding the necessary protection function
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
Effectively suppresses ion migration, enhancing the reliability of communications devices by protecting the electrodes from damage and reducing the risk of short-circuits, while maintaining a simpler and cost-effective manufacturing process compared to mainstream methods.
Implementation Method 1
the first shielding structure can change distribution of electric fields between the bonding layer and the electrode, and block migration of the charged particles from a root
Implementation Method 2
charged particles are disposed in the bonding layer... ions in the bonding material migrate. When the migrating ions combine with a charged electrode, the charged electrode is damaged
Data Source
AI summary
Embodiments of this application disclose a package structure and a communications device to which the package structure is applied. The package structure includes a substrate, a die, and a bonding layer configured to bond the die to the substrate. Charged particles are disposed in the bonding layer. An electrode is disposed on a surface of the die away from the bonding layer. A potential of the electrode is opposite to that of the charged particle. The package structure further includes a first shielding structure. A potential of the substrate is zero. The first shielding structure is located on an outer surface of the die and is located between the bonding layer and the electrode, to prevent the charged particles from migrating to the electrode.