Chip Stack Impedance Matching Using Ultra-Low Loss Dielectrics
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Solution Overview
Problem
Current semiconductor chip stacks face limitations in achieving high clock speeds due to signal transmission issues caused by passive component networks with inexact performance tolerances, leading to reduced operational frequencies compared to intrinsic clock speeds of semiconductor die.
Innovation Solution
Integration of ultra-low loss, high energy density dielectric layers and high permeability magnetic materials within the chip stack to resonate at matching clock frequencies, along with impedance matching and frequency filtering networks, to minimize ringing and optimize clock speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If passive component networks are used for impedance matching and signal transmission, then electrical connections between semiconductor die can be established, but inexact performance tolerances cause signal degradation and reduced clock speeds
Solution Approach 1:
The patent extracts and removes traditional passive component networks (resistors, capacitors, inductors) from the signal transmission path. Instead, it uses direct impedance-matched transmission lines formed by ultra-low loss dielectric materials and geometric features that provide inherent impedance control without discrete passive components, eliminating tolerance accumulation and signal degradation
Solution Approach 2:
The patent changes the dielectric material parameters by using ultra-low loss materials with specific permittivity values (e.g., Er=70 for titanium dioxide, Er=200-800 for perovskite electroceramics) and controls grain size below 50nm to achieve femtosecond polarization response times. These parameter changes enable high-frequency operation with minimal signal loss and maintain impedance matching across the transmission path
2Speed
If traditional dielectric materials are used in transmission lines, then manufacturing is simplified, but signal loss increases and operational frequency is limited
Solution Approach 1:
The patent employs composite material structures combining ultra-low loss dielectric materials (such as titanium dioxide with Er=70, or perovskite electroceramics with Er=200-800) with precisely controlled geometric features. This composite approach achieves both low signal loss and high frequency operation by integrating material properties with structural design for optimal transmission line performance
Solution Approach 2:
The patent applies local quality by positioning specific dielectric materials with tailored permittivity values at different locations along the transmission line. Ultra-high permittivity materials (Er=200-800) are used in resonant structures and impedance matching sections, while ultra-low loss materials are used in main transmission paths, optimizing performance at each critical location
3Reliability
If electromagnetic reflections occur at vias, then manufacturing is easier, but signal integrity deteriorates and ringing increases
Solution Approach 1:
The patent applies preliminary action by incorporating geometric features and impedance matching structures at via locations before signal transmission occurs. These pre-designed features control impedance transitions and minimize reflections at via interfaces, preventing signal integrity issues before they arise during operation
Solution Approach 2:
The patent uses geometric features and dielectric structures as intermediary elements between different impedance zones at via locations. These intermediary structures provide gradual impedance transitions, mediating between the transmission line and via structures to minimize reflections and maintain signal integrity
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 effectively extends impedance-matched electrical lengths, mitigates ringing, and brings the operational clock speed of the chip stack closer to the intrinsic clock speed of the semiconductor die, enhancing signal integrity and performance.
Implementation Method 1
ultra-low loss/high energy density dielectric materials in the form of high permeability and high permittivity dielectrics are periodically arranged along the length of said transmission line to cause it to resonate at a frequency that matches the clock speed
Implementation Method 2
geometric features comprising magnetic materials located in the vicinity of a vertical interconnect (via) to minimize electromagnetic reflections at a via
Implementation Method 3
high energy density dielectric layers consisting of a perovskite electroceramic with a grain size of less than 50 nm and having a relative permittivity, Er, in the range of 200≤Er≤800
Implementation Method 4
high permeability magnetic materials within the chip stack to resonate at matching clock frequencies
Data Source
AI summary
The present invention ultra-low loss high energy density dielectric layers having femtosecond (10−15 sec) polarization response times within a chip stack assembly to extend impedance-matched electrical lengths and mitigate ringing within the chip stack to bring the operational clock speed of the stacked system closer to the intrinsic clock speed(s) of the semiconductor die bonded within chip stack.