Semiconductor Via Formation Using Selective Etch Plugs
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Solution Overview
Problem
Existing semiconductor arrangements face challenges in forming high aspect ratio via openings efficiently and precisely, particularly due to the etch selectivity differences between dielectric layers and substrates, which can lead to time-consuming and imprecise processes.
Innovation Solution
The formation of semiconductor arrangements involves creating composite structures with plugs in dielectric layers, allowing for the precise placement of metal layers and the formation of via openings through these plugs, which improves the etching profile and enables faster, more precise creation of high aspect ratio via openings by utilizing etch selectivity differences between plug materials and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to form via openings through dielectric layers and substrates, then the process can be completed, but the etching is time-consuming and imprecise due to etch selectivity differences
Solution Approach 1:
The patent applies preliminary action by forming plugs within the dielectric layers before the actual via opening etching process. These plugs are pre-formed structures that extend into the substrate, creating a staged approach where the etching process proceeds through multiple discrete stages rather than attempting to etch the entire high aspect ratio via in one operation. This preliminary structuring enables precise control over the etching path and improves both precision and reduces time.
Solution Approach 2:
The patent segments the via opening formation into multiple stages by introducing intermediate plugs at different depths within the dielectric layers. Instead of etching a single continuous high aspect ratio via, the process divides the path into segments separated by these plugs. Each segment can be etched independently with controlled selectivity, improving overall precision while reducing the time required compared to a single continuous etch.
2Productivity
If high aspect ratio via openings are formed directly without intermediate structures, then the structure is simpler, but the etching becomes imprecise and time-consuming
Solution Approach 1:
The plugs are formed as preliminary structures before the final via etching, enabling the complex high aspect ratio via opening to be created through simpler, staged etching operations. Each plug acts as a pre-formed anchor point that guides the subsequent etching, allowing faster and more precise fabrication compared to attempting to etch the complete via in one operation.
Solution Approach 2:
The plugs serve as intermediary structures between the dielectric layers and the substrate. These intermediate elements facilitate the etching process by providing reference points and selective etching paths, acting as mediators that enable precise control during the formation of high aspect ratio via openings without requiring overly complex multi-layer structures.
3Manufacturing precision
If etching is performed through dielectric layers with standard selectivity, then the process is straightforward, but the via openings lack precise profiles
Solution Approach 1:
The patent applies local quality by creating plugs with specific material properties and geometries at localized positions within the dielectric layers. These plugs have different etch selectivity characteristics compared to the surrounding dielectric material, enabling precise control over the etching path at critical locations. This localized differentiation allows for precise via opening profiles while maintaining overall process simplicity.
Solution Approach 2:
The structure employs composite materials by combining different dielectric layers with plugs of distinct material composition. The plugs are formed from materials with different etch selectivity than the surrounding dielectric layers, creating a composite structure that enables precise etching control. This material differentiation allows the etching process to proceed at different rates through different regions, achieving precise via profiles.
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 method allows for the efficient and precise formation of high aspect ratio via openings, improving the overall fabrication process by reducing time and increasing accuracy compared to traditional methods without plugs.
Implementation Method 1
etching through these plugs, which have different etch selectivity than the dielectric layers
Data Source
AI summary
A semiconductor arrangement and methods of formation are provided. The semiconductor arrangement includes a micro-electro mechanical system (MEMS). A via opening is formed through a substrate, first dielectric layer and a first plug of the MEMS. The first plug comprises a first material, where the first material has an etch selectivity different than an etch selectivity of the first dielectric layer. The different etch selectivity of first plug allows the via opening to be formed relatively quickly and with a relatively high aspect ratio and desired a profile, as compared to forming the via opening without using the first plug.