3D Semiconductor Interposer Cavity for Pin Density and Thermal Management
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Solution Overview
Problem
Current 3D semiconductor packages face limitations in reducing form factor and increasing circuit density due to pin count constraints and thermal management issues, particularly with packaging-on-packaging (PoP) techniques and interposer-based solutions.
Innovation Solution
A 3D semiconductor package design utilizing an interposer with a cavity in the substrate allows for smaller conductive bumps and enhanced thermal management through a thermal pad, enabling higher pin counts and reduced package size, while using through substrate vias and redistribution lines for electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If packaging-on-packaging (PoP) techniques are used to stack dies, then form factor is reduced, but the ability to decrease form factor further is limited and pin count to substrate is constrained
Solution Approach 1:
The patent introduces a cavity dimension in the substrate that allows conductive bumps to extend vertically into the substrate depth, effectively adding a third dimension (Z-axis) to the bump structure. This enables more bumps to be packed in the same footprint area, increasing pin count without increasing package footprint.
Solution Approach 2:
The conductive bumps are nested within cavities formed in the substrate, similar to nested dolls. This nesting allows the bumps to be positioned deeper in the substrate, enabling higher density interconnects and increasing the effective pin count to the substrate while maintaining the same package form factor.
2Reliability
If conventional interposer designs are used, then electrical connections are established, but thermal dissipation is insufficient leading to increased operating temperature
Solution Approach 1:
The patent introduces a thermal pad as an intermediary component positioned between the stacked dies and the substrate. This thermal pad acts as a heat transfer mediator, conducting heat away from the dies more effectively than conventional designs, thereby reducing operating temperature while maintaining electrical connection integrity.
Solution Approach 2:
The patent changes the thermal conductivity parameter of the interface between the dies and substrate by introducing a thermal pad with high thermal conductivity. This parameter change enables more efficient heat dissipation, reducing the operating temperature of the stacked dies while preserving the electrical connection functionality.
3Strength
If larger conductive bumps are used, then electrical connections are more robust, but the number of bumps that can be packed is reduced
Solution Approach 1:
By utilizing the vertical dimension through substrate cavities, the patent allows conductive bumps to be positioned at different depths within the substrate. This enables multiple bumps to be stacked vertically within the same footprint area, increasing the number of bumps that can be packed while maintaining adequate connection strength for each individual bump.
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 design achieves a thinner package form factor, increased pin count, and improved thermal dissipation, reducing stress and operating temperature, thereby enhancing the performance and efficiency of semiconductor devices.
Implementation Method 1
Conductive bumps on the interposer electrically couple the interposer to a substrate
Implementation Method 2
The substrate may comprise a heat conductive pad to aid in the dissipation of the heat from the second die
Data Source
AI summary
A 3D semiconductor package using an interposer is provided. In an embodiment, an interposer is provided having a first die electrically coupled to a first side of the interposer and a second die electrically coupled to a second side of the interposer. The interposer is electrically coupled to an underlying substrate, such as a packaging substrate, a high-density interconnect, a printed circuit board, or the like. The substrate has a cavity such that the second die is positioned within the cavity. The use of a cavity may allow smaller conductive bumps to be used, thereby allowing a higher number of conductive bumps to be used. A heat sink may be placed within the cavity to aid in the dissipation of the heat from the second die.