Semiconductor Package Shielding Structure Against Ion Migration
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Solution Overview
Problem
Ion migration in bonding materials of semiconductor packages, particularly in power amplifiers, leads to electrode damage and reliability issues due to ions combining with charged electrodes, causing short-circuits in high-temperature and high-humidity environments.
Innovation Solution
A package structure with a first shielding structure between the bonding layer and electrodes, and a second shielding structure between the bonding layer and pins, configured to manage electric fields and prevent ion migration by maintaining specific potential differences, using die and substrate grounding elements connected by wires to form barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a bonding material with good thermal conductivity (such as gold-tin alloy or sintered silver) is used to bond the die to the substrate, then heat dissipation is improved, but ion migration occurs in the bonding material under impact of working environment, causing electrode damage and device failure
Solution Approach 1:
A shielding layer is introduced as an intermediary component between the bonding material and the electrode. This shielding layer acts as a mediator that blocks ion migration from the bonding material to the electrode, while allowing the bonding material to maintain its thermal conductivity function. The shielding layer thus resolves the contradiction by providing a protective interface that prevents harmful ion interaction while preserving the thermal management capability of the bonding material.
Solution Approach 2:
The structure is segmented into distinct functional layers: the bonding material layer for thermal conduction, the shielding layer for ion barrier protection, and the electrode layer for electrical function. By dividing the originally integrated structure into separate segments with specialized functions, the patent enables each layer to optimize its specific role without compromising the others, thereby resolving the contradiction between heat dissipation and reliability.
2Reliability
If ions in the bonding material migrate and combine with charged electrodes, then the electrode is damaged causing short-circuit, but adding elements or compounds to the bonding layer to block ion migration may cause blocking failure after long use
Solution Approach 1:
The shielding layer serves as a dedicated intermediary component whose sole function is to block ion migration. By separating this protective function from the bonding material, the bonding layer can maintain its original composition and bonding performance without being degraded by long-term use as an ion barrier. The shielding layer absorbs the degradation stress, preserving the bonding layer's service life while providing reliable electrode protection.
Solution Approach 2:
The ion-blocking function is extracted from the bonding material and implemented as a separate shielding layer. This extraction allows the bonding material to focus on its primary functions of thermal conduction and mechanical bonding, while the shielding layer专门 handles ion barrier protection. This separation prevents the bonding layer from suffering blocking failure over time, as the shielding layer is specifically designed and positioned to handle ion migration challenges.
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 blocks ion migration to electrodes and pins, enhancing the reliability of semiconductor packages by preventing short-circuits and ensuring stable operation in harsh environments.
Implementation Method 1
ions in the bonding material migrate. When the migrating ions combine with a charged electrode, the charged electrode is damaged
Implementation Method 2
a first shielding structure... to prevent the charged particles from migrating to the electrode... can change distribution of electric fields between the bonding layer and the electrode
Data Source
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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. The embodiments of this application provide a packaging solution in which ion migration in a bonding material is suppressed, to protect the electrode in the package structure.