Redistribution Layer Isolation Structure for Lower High-Frequency Loss
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Solution Overview
Problem
Capacitive coupling between signal and ground redistribution layers in semiconductor integrated circuits increases insertion loss at high frequencies, and process variations such as sagging of polymer layers complicate manufacturing.
Innovation Solution
Incorporating an isolation region between signal and ground redistribution layers, with support structures in the isolation and signal regions to reduce capacitive coupling and stabilize polymer layers, thereby improving insertion loss and reducing process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If signal and ground redistribution layers are placed close together to reduce area, then area is reduced, but capacitive coupling increases causing higher insertion loss at high frequencies
Solution Approach 1:
An isolation region is introduced as an intermediary element between the signal redistribution layer and ground redistribution layer. This isolation region acts as a mediator that reduces capacitive coupling between the signal and ground layers, thereby reducing insertion loss at high frequencies while allowing the overall structure to maintain a compact area.
2Area of stationary object
If polymer layers are made thinner to reduce area, then area is reduced, but process variations such as sagging increase
Solution Approach 1:
The polymer layer structure is segmented by introducing an isolation region that divides the continuous polymer layer into separate regions. This segmentation provides structural support that prevents sagging and reduces process variations, allowing the use of thinner polymer layers without compromising manufacturing precision.
3Loss of energy
If isolation region is added between signal and ground layers to reduce capacitive coupling, then insertion loss is reduced, but device complexity increases
Solution Approach 1:
The isolation region is designed to serve multiple functions simultaneously: it reduces capacitive coupling between signal and ground layers, provides structural support to prevent polymer layer sagging, and can be integrated into existing fabrication processes. This multi-functionality reduces the need for additional separate structures, thereby limiting the increase in device complexity.
4Manufacturing precision
If support structures are added to stabilize polymer layers, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The support function is merged with the isolation region. Instead of adding separate support structures, the isolation region itself is designed to provide structural support to the polymer layers, preventing sagging and reducing process variations. This merging approach provides the necessary support while avoiding the complexity increase that would result from adding separate support structures.
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 reduces capacitive coupling and stabilizes polymer layers, enhancing performance at high frequencies and improving manufacturing consistency.
Implementation Method 1
Capacitive coupling between signal and ground redistribution layers in semiconductor integrated circuits increases insertion loss at high frequencies
Data Source
AI summary
A device includes a semiconductor chip and a redistribution layer (RDL) structure connected to the semiconductor chip. The redistribution layer structure comprises a first region including: a first bump connected to the semiconductor chip; a second bump; and a plurality of first redistribution layers connected between the first bump and the second bump. The RDL structure includes a second region laterally surrounding the first region, the second region including a plurality of second redistribution layers. The RDL structure includes an isolation region laterally separating the plurality of first redistribution layers from the plurality of second redistribution layer. The isolation region includes at least one region that is straight, continuous, extends from an upper surface of the redistribution layer structure to a lower surface of the first redistribution layer structure, and has at least a selected width.