Stacked IC Package Protective Cap for Gap-Fill Stress Relief
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Solution Overview
Problem
The semiconductor industry faces challenges in integrating semiconductor dies with smaller footprints and higher reliability due to the need for creative packaging techniques that protect gap-filling dielectrics from mechanical and thermal stress.
Innovation Solution
A die structure is developed with multiple tiers of integrated circuit dies, featuring gap-filling dielectrics between tiers, and protective caps made of ductile materials that absorb stress, reducing the risk of cracks and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If gap-filling dielectrics are used between tiers of integrated circuit dies, then the integration density and compactness are improved, but the mechanical and thermal stress resistance deteriorates
Solution Approach 1:
A protective cap made of ductile material is introduced as an intermediary layer between the gap-filling dielectric and the external environment. This cap absorbs mechanical and thermal stress, preventing it from transferring to the dielectric and causing cracks. The cap serves as a stress buffer that protects the vulnerable dielectric while maintaining the compact stacked structure.
Solution Approach 2:
The protective cap is formed over the gap-filling dielectric before subsequent processing steps. This cap acts as a cushioning layer that preemptively protects the dielectric from stress during assembly, operation, and thermal cycling. The ductile material deforms elastically to absorb stress peaks before they can damage the dielectric.
2Productivity
If multiple tiers of integrated circuit dies are stacked, then the productivity and integration density are improved, but the manufacturing complexity increases
Solution Approach 1:
The protective cap is formed over the gap-filling dielectric before the second tier of dies is attached. This preliminary protective measure ensures that the dielectric is already protected when subsequent dies and interconnect structures are added, preventing stress damage during the assembly process and reducing the need for complex post-assembly repairs or rework.
Solution Approach 2:
The protective cap is formed within the device region, nested between the tiers of dies and the overlying structures. This nested configuration provides protection without increasing the overall footprint or requiring additional external components, maintaining the compact integrated structure while adding the necessary protective function.
3Reliability
If protective caps are added to protect gap-filling dielectrics, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The protective cap is formed using the same dielectric material as the gap-filling dielectric, creating a homogeneous structure. This eliminates the need for additional material interfaces and reduces structural complexity while maintaining the protective function. The continuous dielectric layer provides stress protection without introducing heterogeneous materials that would complicate the device architecture.
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 increases the reliability of the die structure by protecting gap-filling dielectrics from stress, allowing for smaller and more reliable integration of semiconductor dies.
Implementation Method 1
The protective cap is formed of a ductile material that protects the gap-filling dielectric during processing by absorbing stress
Data Source
AI summary
Integrated circuit packages and methods of forming the same are provided. In an embodiment, a device includes: a first integrated circuit die; a second integrated circuit die; a gap-fill dielectric between a first sidewall of the first integrated circuit die and a second sidewall of the second integrated circuit die; a protective cap overlapping the gap-fill dielectric, the first sidewall of the first integrated circuit die, and the second sidewall of the second integrated circuit die; and an isolation layer around the protective cap, the isolation layer disposed on the first integrated circuit die and the second integrated circuit die.