Conductive Plug Vertical Profile via Etch Stop Layer
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Solution Overview
Problem
As semiconductor devices miniaturize, the increased aspect ratio of contacts during etching leads to difficulties in achieving desired vertical profiles, often resulting in tapered or bowing profiles due to ion bombardment and over-etching.
Innovation Solution
A structure with multiple etching block layers, including a hard mask layer, a vertical liner, and an etch stop layer, is used to maintain a vertical profile of the plug opening, preventing deformation during the etching process by forming a 'horizontal U-shaped' etching block layer around the plug opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the contact is downsized to meet miniaturization requirements, then the device size is reduced, but the aspect ratio of the contact is increased making etching difficult and reducing the process window
Solution Approach 1:
The patent segments the etching block layer into multiple distinct layers (hard mask layer, first dielectric layer, etch stop layer, second dielectric layer) with different materials and properties. Each layer serves a specific function in controlling the etching process, allowing precise management of the high aspect ratio contact etching while maintaining miniaturization.
Solution Approach 2:
The patent applies different materials with specific local properties to different regions of the etching block layer structure. The hard mask layer provides etching resistance at the top, the etch stop layer prevents over-etching at the interface, and the dielectric layers provide structural support. This local differentiation of material properties enables precise control over the etching profile in high aspect ratio contacts.
2Productivity
If conventional etching is performed on high aspect ratio contacts, then the etching process can be completed, but undesired profiles such as tapered and/or bowing profiles are observed instead of desired vertical profiles
Solution Approach 1:
The patent applies preliminary anti-action by forming the etching block layer structure with multiple functional layers before the etching process begins. The hard mask layer, etch stop layer, and dielectric layers are预先 configured to counteract the ion bombardment effects and over-etching that would otherwise cause tapered and bowing profiles, ensuring vertical profile formation throughout the etching process.
Solution Approach 2:
The etch stop layer acts as an intermediary between the upper etching block layers and the underlying contact region. It provides a controlled interface that prevents uncontrolled etching penetration while allowing the etching process to proceed through the high aspect ratio contact, thereby maintaining vertical profiles and preventing over-etching damage.
Data Source
AI summary
Provided is a structure with a conductive plug including a substrate, a first dielectric layer, an etch stop layer, a second dielectric layer, a conductive plug and a liner. The substrate has a conductive region therein. The first dielectric layer, the etch stop layer and the second dielectric layer are sequentially formed on the substrate and have at least one opening therethrough. Besides, the opening has a substantially vertical sidewall. The conductive plug fills in the opening and is electrically connected to the conductive region. The liner surrounds the upper portion of the conductive plug. A method of forming a structure with a conductive plug is further provided.