Multilayer Etch Stop Structure for Low-Resistance Semiconductor Contacts
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Solution Overview
Problem
Highly integrated semiconductor devices face challenges in achieving high-speed operation due to increased resistance and capacitance in metal lines as they are scaled down, leading to deterioration in operating characteristics.
Innovation Solution
A semiconductor device is designed with a multi-layered etch stop layer comprising different insulating materials, including a metallic nitride layer, a carbon-containing layer, and a nitrogen-free layer, to prevent damage to metal-containing conductive patterns during contact hole formation, thereby reducing resistance and improving electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metal lines are scaled down to achieve high integration, then device integration is improved, but resistance and capacitance in metal lines increase leading to deterioration in operating characteristics
Solution Approach 1:
The etch stop layer is divided into multiple sub-layers with different materials and functions. The first etch stop layer contains a metallic element and provides adhesion and etch stop functionality. The second etch stop layer contains carbon and provides diffusion barrier and etch stop functionality. This segmentation allows each layer to be optimized for specific functions, enabling effective protection of scaled-down metal lines while maintaining high device integration.
2Ease of manufacture
If a single-layer etch stop layer is used, then manufacturing process is simple, but metal-containing conductive patterns are damaged during contact hole formation
Solution Approach 1:
The etch stop structure uses composite materials with the first etch stop layer containing a metallic element (such as titanium, tantalum, or tungsten) and the second etch stop layer containing carbon (such as silicon carbide or amorphous carbon). This composite structure provides both etch stop functionality and protection against damage to metal-containing conductive patterns during contact hole formation, while maintaining manufacturing feasibility through sequential deposition processes.
3Reliability
If etching process is performed to form contact holes, then electrical connection is achieved, but metal-containing conductive patterns are damaged
Solution Approach 1:
The first etch stop layer containing a metallic element acts as an intermediary protective layer between the etching process and the metal-containing conductive patterns. This layer provides etch stop functionality that prevents over-etching from reaching and damaging the underlying conductive patterns, while still allowing the etching process to successfully form contact holes for electrical connection.
Data Source
AI summary
A semiconductor device including a metal pattern on a semiconductor substrate; an etch stop layer covering the metal pattern, the etch stop layer including a sequentially stacked first insulation layer, second insulation layer, and third insulation layer; an interlayer dielectric layer on the etch stop layer; and a contact plug penetrating the interlayer dielectric layer and the etch stop layer, the contact plug being connected to the metal pattern, wherein the first insulation layer includes a first insulating material that contains a metallic element and nitrogen, wherein the second insulation layer includes a second insulating material that contains carbon, and wherein the third insulation layer includes a third insulating material that does not contain a metallic element and carbon.