3D IC Transmission Line With Shielding Substrate
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Solution Overview
Problem
As semiconductor technology advances and chip package size shrinks, the increasing capacitance between metal layers in CMOS structures compromises the performance of RF devices due to larger distances between metal layers, affecting signal transmission and impedance control.
Innovation Solution
The implementation of a transmission line structure within semiconductor structures, featuring a ground plane and signal line separated by an electrically insulating layer, with a second semiconductor substrate providing enhanced shielding and impedance control, and the use of switches to couple or decouple signal and ground lines for adjustable transmission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If chip package size is shrunk and metal layers are placed closer together, then area is reduced, but capacitance between metal layers increases compromising RF performance
Solution Approach 1:
A dielectric layer is introduced as an intermediary between adjacent metal layers in the transmission line structure. This dielectric layer has a lower dielectric constant than conventional materials, which reduces the capacitance between metal layers while maintaining the compact chip package size. The dielectric layer acts as a mediator that allows close spacing without the harmful capacitive coupling that would otherwise degrade RF performance.
2Area of moving object
If transmission line size is reduced for smaller packages, then area is reduced, but impedance control becomes more difficult
Solution Approach 1:
The dielectric constant of the insulating material is changed to a lower value compared to conventional materials. This parameter change allows the transmission line to maintain proper impedance control even when the physical dimensions are reduced. The adjusted dielectric parameter compensates for the reduced geometry, enabling impedance control in smaller transmission lines without requiring proportionally tighter manufacturing tolerances.
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 configuration allows for improved signal propagation and impedance control, enabling smaller transmission lines to handle higher frequencies while maintaining performance, and allows for adjustable transmission properties by varying the electrical connection between lines.
Implementation Method 1
The signal line and ground line are generally supported and separated by some type of insulating substrate or material, such as a dielectric
Implementation Method 2
a second semiconductor substrate providing enhanced shielding and impedance control
Data Source
AI summary
A semiconductor transmission line substructure and methods of transmitting RF signals are described. The semiconductor transmission line substructure can include a substrate; a first signal line over the substrate; a first ground line over the substrate; and a second semiconductor substrate over the substrate. The first signal line, the first ground line and the second semiconductor substrate are each vertically spaced apart from one another and can be separated from one another by at least one electrically insulating layer.