Offset Stacked IC Die Configuration for High Density Packaging
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Solution Overview
Problem
Current integrated circuit packaging technologies face limitations in die stacking density and structural integrity, particularly in portable electronics, where the need for increased density and miniaturization is driven by demand for smaller, more complex devices.
Innovation Solution
The method involves offset stacking of integrated circuit dies with an interdie layer providing spacing and structural integrity, allowing for a cascaded configuration that increases die density without die protrusion, using a substrate and attach layers like epoxy or adhesive films for attachment and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If same die stacking with all bond pads at one side is used, then staircase stacking is enabled eliminating the need for thick spacers, but the number of die that can be stacked is still restricted by package size causing die protrusion
Solution Approach 1:
The patent applies asymmetry by offsetting alternating dies in the stack relative to each other, creating a staggered configuration where bond pads are distributed across multiple sides rather than concentrated at one side. This asymmetric arrangement allows dies to be stacked higher without protruding from the package boundaries, directly resolving the contradiction between stacking precision and package volume.
Solution Approach 2:
The patent transitions from a single-dimensional stacking approach (all dies aligned on one axis) to a multi-dimensional offset stacking configuration. By alternating offsets in different directions along the stack, the design utilizes multiple spatial dimensions to accommodate more dies within the same package footprint, effectively increasing density without increasing package size.
2Quantity of substance
If more integrated circuits are mounted on a single circuit board, then integrated circuit density increases, but the real estate available for mounting individual integrated circuits becomes limited
Solution Approach 1:
The patent resolves this contradiction by transitioning from two-dimensional planar mounting to three-dimensional stacked mounting with offset configuration. This vertical dimensionality change allows multiple integrated circuits to be mounted in a stacked arrangement rather than spread across the substrate surface, dramatically increasing circuit density without consuming additional substrate area.
Solution Approach 2:
The offset stacked die configuration enables a nested arrangement where multiple dies are positioned at different vertical levels within the same horizontal footprint. This nesting approach allows circuits to be packed more efficiently by utilizing vertical space, thereby increasing the quantity of circuits that can be mounted on a given substrate area.
3Speed
If multi-chip packages are used to increase density and miniaturization, then signal propagation speed improves, but structural integrity and manufacturing yield need improvement
Solution Approach 1:
The patent applies asymmetry in the offset stacking configuration to distribute mechanical stresses more evenly throughout the package structure. By alternating the offset direction of successive dies, the design creates a more balanced load distribution that enhances structural integrity and reduces the risk of failure, thereby improving reliability while maintaining the high-density, fast-signal-propagation benefits of multi-chip packaging.
Data Source
AI summary
A method of manufacture of an integrated circuit package system comprises: providing a first integrated circuit die; attaching a second integrated circuit die over the first integrated circuit die and offset from the first integrated circuit die in substantially one dimension; forming an interdie layer over the second integrated circuit die; attaching a third integrated circuit die over the interdie layer and substantially aligned to the second integrated circuit die; and attaching a fourth integrated circuit die over the third integrated circuit die and offset from the third integrated circuit die in substantially the same magnitude and substantially the opposite direction as the second integrated circuit die to the first integrated circuit die.