Leadframe-Based Interposer for Stacked Die Packages
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Solution Overview
Problem
Conventional methods of stacking microelectronic die packages are challenging, expensive, and prone to misalignment, requiring precise alignment and inspection of individual leads, which is difficult to standardize due to varying die and package sizes.
Innovation Solution
The use of exposed metal leads as a framework for interconnecting die packages, where connectors selectively wet to the leads but not the casing, allowing for reliable lead-to-lead interconnections without the need for precise alignment, and enabling standardized package sizes to accommodate differently sized dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods of stacking microelectronic die packages are used with precise alignment and inspection of individual leads, then reliable electrical coupling is achieved, but the manufacturing process becomes challenging, expensive, and difficult to standardize
Solution Approach 1:
The patent introduces an interposer substrate as an intermediary component between stacked die packages. The interposer provides a standardized platform with pre-configured connection structures (such as ball grids or pad arrays) that simplify the interconnection process. Instead of directly aligning and inspecting individual leads between dies, the interposer mediates the connection, providing mechanical support and electrical pathways that reduce manufacturing complexity while maintaining coupling reliability.
Solution Approach 2:
The interposer substrate serves multiple functions simultaneously: it provides mechanical support for stacking, establishes electrical connections between dies, enables standardized packaging dimensions, and facilitates heat dissipation. This multi-functional approach allows different sized dies to be stacked on a common platform, standardizing the packaging process while maintaining reliable electrical coupling across various configurations.
2Manufacturing precision
If precise alignment and inspection of individual leads are required for stacking, then reliable interconnections are achieved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The interposer substrate acts as a mediator that provides a standardized reference plane and pre-configured connection structures. This eliminates the need for complex real-time alignment and inspection systems for individual leads, as the interposer's standardized geometry and connection patterns simplify the stacking process to more tolerant alignment requirements while maintaining manufacturing precision through the interposer's structured design.
Solution Approach 2:
The patent changes the geometric parameters of the packaging system by introducing standardized interposer dimensions and connection patterns. This parameter standardization allows for more relaxed alignment tolerances during stacking, reducing the complexity of alignment and inspection systems while maintaining sufficient manufacturing precision through the interposer's structured geometry and standardized interface configurations.
3Ease of manufacture
If standardized package sizes are used to accommodate differently sized dies, then manufacturing is simplified, but the package dimensions must accommodate the largest die in the stack
Solution Approach 1:
The interposer substrate provides a universal standardized platform that can accommodate dies of varying sizes through its multi-functional design. The interposer's standardized dimensions and connection patterns allow different sized dies to be mounted on the same platform, simplifying manufacturing and inventory management. The interposer effectively bridges the size mismatch between smaller dies and the larger standardized package footprint, enabling standardization without requiring the package area to be exactly matched to each individual die size.
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 approach simplifies the stacking process, reduces alignment requirements, and allows for reliable electrical coupling of die packages, enabling efficient and standardized packaging of variously sized dies in a compact form.
Implementation Method 1
connectors selectively wet to the leads but not the casing, allowing for reliable lead-to-lead interconnections
Data Source
AI summary
Microelectronic die packages, stacked systems of die packages, and methods of manufacturing thereof are disclosed herein. In one embodiment, a method of manufacturing a microelectronic device includes stacking a first die package having a first dielectric casing on top of a second die package having a second dielectric casing, aligning first metal leads at a lateral surface of the first casing with second metal leads at a second lateral surface of the second casing, and forming metal solder connectors that couple individual first leads to individual second leads. In another embodiment, the method of manufacturing the microelectronic device may further include forming the connectors by applying metal solder to a portion of the first lateral surface, to a portion of the second lateral surface, and across a gap between the first die package and the second die package so that the connectors are formed by the metal solder wetting to the individual first leads and the individual second leads.