Etched Interconnect Geometry for Lower High-Frequency Insertion Loss
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Solution Overview
Problem
Existing interconnect structures formed by chemical etching exhibit varying insertion loss in signal transmission, particularly at high frequencies, due to etching solution residue causing undercut areas with uncontrollable etch angles and lengths.
Innovation Solution
The interconnect structure is formed on a substrate using chemical etching, with undercut areas created on both sides of the interconnect due to etching solution residue. The etch angle and etch length in these undercut areas are controlled to minimize the insertion loss during signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical etching process is used to form interconnect, then interconnect structure is created, but etching solution residue causes undercut areas with high insertion loss
Solution Approach 1:
The patent applies parameter changes by modifying the etching process parameters including using a two-stage etching approach with different etchants, controlling etching time and temperature, and adjusting photoresist thickness to minimize undercut formation while maintaining etching effectiveness. This resolves the contradiction by optimizing etching parameters to reduce insertion loss without sacrificing manufacturability
Solution Approach 2:
The patent implements preliminary action through pre-etching treatments and photoresist optimization before the main etching process. By preparing the substrate and photoresist in advance with specific surface treatments and thickness control, the process prevents excessive undercut formation from the outset, thereby reducing insertion loss while maintaining efficient interconnect formation
2Manufacturing precision
If undercut areas are formed due to etching solution residue, then etch angle and etch length vary, but insertion loss increases
Solution Approach 1:
The patent implements feedback control through iterative process optimization where etching parameters are adjusted based on measured undercut dimensions and insertion loss performance. By monitoring the relationship between etch angle, etch length, and signal transmission quality, the process is refined to achieve optimal parameters that minimize energy loss while maintaining manufacturing precision
Solution Approach 2:
The patent applies partial action by using a two-stage etching process where the first stage creates initial undercut control and the second stage completes the etching with refined parameters. This staged approach allows precise control of etch angle and etch length, preventing excessive undercut formation that would increase insertion loss
3Productivity
If conventional etching process is used, then manufacturing is simple, but high-frequency signal transmission is hindered by high insertion loss
Solution Approach 1:
The patent maintains manufacturing efficiency by using conventional chemical etching equipment and processes, but improves signal transmission speed by optimizing etching parameters to reduce insertion loss. The two-stage etching process with controlled parameters achieves both high productivity and enhanced high-frequency signal transmission capability
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
By controlling the etch angle and etch length, the insertion loss of the interconnect is significantly reduced, thereby enhancing the high-frequency/high-speed signal transmission efficiency.
Implementation Method 1
The interconnect is formed on the substrate by chemical etching process
Data Source
AI summary
An interconnect structure for insertion loss reduction in signal transmission and a method thereof are disclosed. In an embodiment, an interconnect is formed on a substrate by chemical etching process, and when the interconnect is protected by photoresist in chemical etching process, the etching direction of etching solution is not oriented, so undercut areas are respectively formed on both sides of a bottom of the interconnect at contact of the interconnect and the substrate because of etching solution residue after the etching process. An included angle formed in the undercut area between the interconnect and the substrate is defined as an etch angle, and a length of the portion, exposing in the undercut area, of the substrate is defined as an etch length. Controlling sizes of the etch angle and the etch length can reduce an insertion loss in signal transmission.