Interfacial Bonding Test Structures for 3D Semiconductor Packages
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Solution Overview
Problem
Semiconductor packages face challenges such as warpage, cracking, and delamination due to thermal expansion mismatch between components, which affect the integrity of solder connections and overall package performance, particularly in high-performance computing applications.
Innovation Solution
The use of reinforcement structures, including stiffener rings and underfill materials, to stabilize the package substrate and mitigate thermal stresses, combined with interfacial bonding test structures for evaluating bonding energies using a four-point bending test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chips are stacked in 3-dimensional devices to improve integration density, then integration density and bandwidth are improved, but mechanical issues such as warpage, cracking, and delamination occur due to thermal expansion mismatch
Solution Approach 1:
The patent applies preliminary action by forming test structures and reinforcement features (such as stiffener rings and underfill materials) during the fabrication process before the actual thermal stress conditions occur. This allows bonding energies to be determined in advance, enabling selection of bonding parameters that will prevent warpage, cracking, and delamination when the device operates under thermal stress.
Solution Approach 2:
The patent utilizes parameter changes by measuring bonding energies under controlled conditions and using this data to optimize bonding parameters (such as temperature, pressure, and time) for the stacking process. By changing and optimizing these parameters based on measured bonding characteristics, the patent achieves reliable mechanical bonding while maintaining high integration density in 3-dimensional devices.
2Reliability
If bonding parameters are optimized to improve interfacial bonding strength, then bonding reliability is improved, but the complexity of the fabrication process increases
Solution Approach 1:
The patent applies self-service by incorporating test structures that automatically provide bonding energy measurements during the fabrication process itself. These test structures require additional processing steps, but they enable the system to self-determine optimal bonding parameters without external intervention or complex additional testing equipment, thereby reducing overall process complexity while improving bonding reliability.
3Reliability
If test structures are added to determine bonding energies, then bonding reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies merging by combining the test structures with the actual device fabrication process. The test structures are formed using the same deposition and patterning steps as the device structures, and the bonding process that joins device components also joins test structures. This integration allows bonding energies to be determined without adding separate manufacturing steps, thereby maintaining manufacturing simplicity while improving bonding reliability.
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
Enhances co-planarity of solder connections, reduces mechanical distortions, and improves the reliability of semiconductor packages by predicting and managing thermal stresses, thereby ensuring stable interfacial bonding.
Implementation Method 1
The sandwich structure may be placed in a four-point bending apparatus and subjected to bending moments. An interfacial bonding energy may be determined based on a critical force that generates steady-state interfacial crack propagation.
Implementation Method 2
An interfacial bonding energy may be determined based on a critical force that generates steady-state interfacial crack propagation.
Implementation Method 3
there are many challenges related to fabricating and operating 3-dimensional devices such as mechanical issues related to thermal expansion mismatch between package components leading to warpage, cracking, delamination, etc.
Implementation Method 4
mechanical issues related to thermal expansion mismatch between package components leading to warpage, cracking, delamination, etc.
Data Source
AI summary
An embodiment interfacial bonding test structure may include a first substrate having a first planar surface, a second substrate having a second planar surface that is parallel to the first planar surface, a first semiconductor die, and a second semiconductor die, each semiconductor die bonded between the first substrate and the second substrate thereby forming a sandwich structure. The first semiconductor die and the second semiconductor die may be bonded to the first surface with a first adhesive and may be bonded to the second surface with a second adhesive. The first semiconductor die and the second semiconductor die may be displaced from one another by a first separation along a direction parallel to the first planar surface and the second planar surface. The second substrate may include a notch having an area that overlaps with an area of the first separation in a plan view.