Stacked Semiconductor Package Wiring to Minimize Signal Stubs
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Solution Overview
Problem
In semiconductor packages, longer wires connected between upper structure semiconductor chips and the substrate can act as stubs, causing signal attenuation and resonant frequency nulls, which deteriorate signal quality and reduce eye margin.
Innovation Solution
The semiconductor package connects semiconductor chips in the upper structure directly to each other via wire bonding instead of connecting them to the substrate, thereby reducing the length of wires and minimizing the likelihood of stub formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor chips in the upper structure are connected to the substrate by wire bonding, then electrical connection is achieved, but wire length increases causing stub formation and signal quality deterioration
Solution Approach 1:
The patent transitions from a two-dimensional connection architecture (all chips connecting to substrate) to a three-dimensional stacked architecture where upper chips connect directly to each other vertically. This dimensional change reduces wire length by eliminating the need for wires to extend from upper chips all the way to the substrate, thereby reducing stub formation and improving signal quality
2Reliability
If wire bonding is used for connecting upper structure chips to substrate, then electrical connection is established, but signal attenuation and resonant frequency nulls occur
Solution Approach 1:
The patent extracts the problematic long wires that cause signal attenuation and stub formation from the connection architecture. By removing the intermediate substrate connection layer for upper chips and implementing direct chip-to-chip bonding, the harmful long wire segments are eliminated, thereby reducing signal attenuation and resonant frequency nulls
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 reduces the probability of wires acting as stubs, leading to improved signal characteristics, enhanced eye margin, and better signal quality for semiconductor chips.
Implementation Method 1
connecting some of connection pads of the substrate and some of data pads of the first semiconductor chip by wire bonding; connecting the connection pads of the substrate and data pads of the second semiconductor chip by wire bonding; and connecting some of the data pads of the second semiconductor chip and some of data pads of the third semiconductor chip by wire bonding
Data Source
AI summary
A semiconductor package includes: a substrate including a plurality of connection pads; a first semiconductor chip on the substrate and including a plurality of first data pads on an upper surface thereof; a second semiconductor chip on the first semiconductor chip and including a plurality of second data pads on an upper surface thereof; a third semiconductor chip on the second semiconductor chip and including a plurality of third data pads on an upper surface thereof; and a plurality of connection members for connecting some of the plurality of connection pads and some of the plurality of first data pads, connecting the plurality of connection pads and the plurality of second data pads, and connecting some of the plurality of second data pads and some of the plurality of third data pads.