Surface-Mount Die Support Structures for Robust Package Bonding
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Solution Overview
Problem
Traditional solder joints in semiconductor device assemblies are susceptible to breakage during assembly, leading to open-circuit or short-circuit issues due to excessive force, necessitating more mechanically robust solutions.
Innovation Solution
The implementation of surface-mount die support structures with conductive pillars and bond materials, which provide mechanical support and electrical connectivity between stacked package elements, allowing for accurate compression and thermo-compressive bonding to prevent warpage and ensure reliable interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solder joints are used to connect stacked package elements, then electrical connectivity is achieved, but the joints are susceptible to breakage during assembly due to excessive force
Solution Approach 1:
Compliant features are incorporated into the interconnect structure beforehand to cushion and absorb excessive force during assembly. These compliant features act as mechanical buffers that prevent direct transmission of damaging forces to the solder joints, thereby preventing breakage while maintaining electrical connectivity.
Solution Approach 2:
The interconnect structure is designed with adjustable geometric parameters such as height, width, and material composition that can be optimized to balance mechanical robustness and electrical performance. By changing these parameters, the interconnect can accommodate varying assembly forces while maintaining reliable electrical connection.
2Productivity
If excessive force is applied during bonding of adjacent dies, then assembly is completed, but solder joints are damaged leading to open-circuit or short-circuit
Solution Approach 1:
The compliant features are pre-designed into the interconnect structure to absorb assembly forces, allowing rapid bonding processes without compromising electrical connectivity. This enables high-speed assembly while preventing the excessive force from causing open or short circuits.
Solution Approach 2:
The compliant features act as intermediary elements between the bonding process and the solder joints, mediating the force transmission. This intermediary structure allows assembly to proceed at high speed while protecting the electrical connectivity from damage.
3Reliability
If die support structures are added to mechanically support interconnects, then mechanical robustness is enhanced, but device complexity increases
Solution Approach 1:
The die support structure and interconnect are merged into a single integrated component. This combination provides mechanical support for the interconnect while simultaneously establishing electrical connectivity, thereby enhancing mechanical robustness without proportionally increasing structural complexity.
Solution Approach 2:
The interconnect structure is designed to perform multiple functions: providing electrical connectivity, offering mechanical support, and accommodating assembly forces. This multi-functionality reduces the need for separate dedicated support structures, maintaining simplicity while enhancing robustness.
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 die support structures enhance the mechanical robustness of semiconductor device assemblies, preventing warpage-induced damage and ensuring consistent solder joint formation, thereby improving manufacturing yield and reducing the risk of electrical failures.
Implementation Method 1
a metal solder can be placed between the contacts and reflowed to form a conductive joint
Implementation Method 2
allowing for accurate compression and thermo-compressive bonding to prevent warpage and ensure reliable interconnects
Data Source
AI summary
A semiconductor device assembly is provided. The assembly includes a first package element and a second package element disposed over the first package element. The assembly further includes a plurality of die support structures between the first and second package elements, wherein each of the plurality of die support structures has a first height, a lower portion surface-mounted to the first package element and an upper portion in contact with the second package element. The assembly further includes a plurality of interconnects between the first and second package elements, wherein each of the plurality of interconnects includes a conductive pillar having a second height, a conductive pad, and a bond material with a solder joint thickness between the conductive pillar and the conductive pad. The first height is about equal to a sum of the solder joint thickness and the second height.