Electronic Package Thermal Path for Laser Solder Reflow
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Solution Overview
Problem
The laser-assisted bonding process in semiconductor packaging is limited by insufficient thermal energy penetration through the package layer, leading to non-wetting of solder materials due to the inability of the laser to penetrate through the package layer, causing thermal stress concentration and warpage issues.
Innovation Solution
Embedding action structures, such as pillars, within the package layer to facilitate heat conduction, allowing the laser to penetrate and transfer heat energy to the bonding elements, ensuring effective reflow of solder materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a package layer is used to cover the electronic element, then the electronic element is protected, but the laser cannot penetrate through the package layer, resulting in insufficient thermal energy for the bonding elements
Solution Approach 1:
The patent introduces an action structure (such as a through-via or conductive pillar) as an intermediary component that enables the laser to penetrate through the package layer. This action structure serves as a mediator that transmits thermal energy from the laser to the bonding elements, resolving the contradiction between package layer protection and laser penetration capability
Solution Approach 2:
The patent applies local quality by creating a specific region (action structure) within the package layer that has different optical and thermal properties. This localized structure allows laser penetration and thermal energy transmission at specific locations while maintaining the overall protective function of the package layer
2Reliability
If conventional thermal process is used for bonding, then the entire structure is heated, but thermal stress concentration and warpage occur due to different coefficients of thermal expansion
Solution Approach 1:
The patent applies local quality by concentrating thermal energy delivery to specific locations through the action structures. Instead of heating the entire structure uniformly, the laser energy is focused through the action structures to provide localized heating at the bonding elements, thereby reducing thermal stress concentration and warpage while maintaining bonding effectiveness
Solution Approach 2:
The patent replaces the conventional mechanical/conventional thermal heating system with a laser-based localized heating system. The laser provides precise, controllable thermal energy delivery through the action structures, substituting the non-selective conventional heating method and enabling better control over thermal stress distribution
3Productivity
If laser assisted bonding is used to reduce thermal process time, then productivity improves, but the laser energy cannot reach the bonding elements under the package layer
Solution Approach 1:
The action structure serves as a mediator that enables laser energy to reach the bonding elements. By introducing this intermediary pathway, the laser can effectively deliver thermal energy through the package layer to the bonding elements, maintaining the productivity benefits of laser assisted bonding while solving the penetration problem
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 solution effectively addresses the non-wetting issue of solder materials by enhancing heat transfer, reducing thermal stress, and improving the reliability of the semiconductor package by ensuring proper bonding.
Implementation Method 1
a thermal conduction is formed between the bonding element and the action structure
Implementation Method 2
the laser to penetrate and transfer heat energy to the bonding elements, ensuring effective reflow of solder materials
Data Source
AI summary
An electronic package is provided, in which an electronic element is disposed on an upper side of a circuit structure, a package layer covers the electronic element, and an action structure is embedded in the package layer, so that the action structure is exposed from a surface of the package layer, and then a bonding element is disposed on a lower side of the circuit structure and corresponding to the position of the action structure, so as to form a thermal conduction between the bonding element and the action structure. Therefore, a laser can transfer heat energy to the bonding element via the action structure, so that a solder material on the bonding element can be reflowed.