Dual-Layer Solder Joint Structure for Stable Chip Bonding
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Solution Overview
Problem
The challenge lies in achieving stable bonding between electronic components in electronic devices without compromising their performance, as high-temperature solders cause warping and low-temperature solders result in low strength intermetallic compounds, leading to unreliable bonding.
Innovation Solution
A dual-layer soldering approach using a high-temperature solder layer bonded to one component and a low-temperature solder layer bonded through atomic diffusion to the other, forming strong intermetallic compounds on the bonding interface, while avoiding the formation of intermetallic compounds during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature solder is used for bonding, then bonding strength is improved, but electronic components are warped and performance is changed
Solution Approach 1:
The bonding structure is segmented into three distinct layers: a first solder layer bonded to the first electronic component, a second solder layer bonded to the second electronic component, and an intermediate layer between them. This segmentation allows each layer to serve specific functions - the first and second solder layers provide strong bonding to their respective components, while the intermediate layer facilitates bonding between them at lower temperatures, thus resolving the contradiction between bonding strength and component stability.
Solution Approach 2:
The intermediate layer acts as a mediator between the first and second solder layers. It enables the bonding of two electronic components that would otherwise require high-temperature soldering by providing a lower-temperature bonding interface. This intermediary layer transfers and distributes bonding forces, allowing strong overall bonding while maintaining lower temperatures at the component interfaces, thereby preventing warping and performance changes.
2Reliability
If low-temperature solder is used for bonding, then component warping is avoided, but bonding strength is reduced due to high brittleness and low elongation rate
Solution Approach 1:
The bonding structure is divided into multiple functional layers where the first and second solder layers use low-temperature materials bonded to their respective electronic components, avoiding warping. The intermediate layer provides the necessary mechanical strength and ductility. This segmentation allows low-temperature soldering at component interfaces while maintaining overall bonding strength through the intermediate layer.
Solution Approach 2:
The bonding structure employs a composite material system consisting of different solder materials with complementary properties. The first and second solder layers use low-temperature, low-brittleness materials for gentle bonding to components. The intermediate layer uses materials with appropriate mechanical properties to compensate for the brittleness of low-temperature solders, creating a composite structure that achieves both low-temperature bonding and high overall strength.
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
This method enhances the stability and reliability of the bonding between electronic components, reducing the risk of warping and deformation, and improving the overall performance and durability of the electronic assembly.
Implementation Method 1
a material constituting the low-temperature solder layer is partially the same as that constituting the high-temperature solder layer, so that the low-temperature solder layer is bonded to the high-temperature solder layer through atomic diffusion
Data Source
Figure 1~2a
Figure 2b~3b
Figure 4~6a
AI summary
This application relates to the field of electronic technologies, and provides an electronic assembly and an electronic device, to resolve low stability of bonding between electronic components. The electronic assembly includes: a first electronic component, where a first active surface of the first electronic component has at least one first solder pad; a second electronic component, where a second active surface of the second electronic component has at least one second solder pad, and the second active surface faces the first active surface; and at least one first soldering portion, where one first soldering portion is located between one first solder pad and one second solder pad, and the first soldering portion is bonded to the first solder pad and the second solder pad on both sides of the first soldering portion. The first soldering portion includes a high-temperature solder layer and a low-temperature solder layer. The high-temperature solder layer is disposed close to the first solder pad and is bonded to the first solder pad. The low-temperature solder layer is disposed close to the second solder pad and is bonded to the second solder pad. A melting point of the low-temperature solder layer is lower than that of the high-temperature solder layer, and a material constituting the low-temperature solder layer is partially the same as that constituting the high-temperature solder layer.