Gradient SiBN Etch Stop Layer for Semiconductor Precision
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Solution Overview
Problem
The semiconductor industry faces challenges in maintaining process margins due to reduced overlay margins for preventing bridging of patterns among layers during fabrication, particularly in the etching process, where existing etch stop layers do not effectively control the etch profile.
Innovation Solution
A semiconductor structure is developed with an etch stop layer composed of Silicon (Si), Nitrogen (N), and Boron (B) elements, formed using Plasma Enhanced Chemical Vapor Deposition (PECVD), where the concentration of these elements varies along the thickness to improve the etch profile, with a SiBN compound layer and a top SiN compound layer, enhancing anisotropic etching and uniform bottom recess profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etch stop layer is used, then the etching process can proceed, but the etch profile is poor and process margins are reduced
Solution Approach 1:
The etch stop layer employs a gradient concentration profile where Boron content varies through the layer thickness. The concentration of B is highest at the interface with the underlying layer and decreases toward the top, creating locally optimized etch resistance and profile control at different depths within the layer
Solution Approach 2:
The etch stop layer is formed as a composite structure containing multiple elements (Si, N, B) in varying concentrations. This composite material approach allows simultaneous optimization of etch selectivity, anisotropy, and stopping power by combining the beneficial properties of different elements in a gradient distribution
2Manufacturing precision
If overlay margin is reduced to accommodate smaller critical dimensions, then minimum critical dimension decreases, but bridging of patterns among layers increases
Solution Approach 1:
The gradient etch stop layer is designed to preemptively prevent etch profile degradation and pattern bridging by establishing optimal etch resistance gradients before the etching process begins. The pre-configured concentration profile ensures that the etch front encounters progressively varying resistance that maintains clean, controlled etching throughout the process
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 etch stop layer with gradient concentration of Si, N, and B elements effectively improves the etch profile, providing larger process margins and preventing bridging issues, thereby enhancing the precision and reliability of semiconductor device fabrication.
Implementation Method 1
formed using Plasma Enhanced Chemical Vapor Deposition (PECVD)
Data Source
AI summary
A semiconductor structure is disclosed. The semiconductor structure includes a base layer and an etch stop layer having a plurality of elements and in physical contact with the base layer. The etch stop layer have a Boron (B) element configured to improve the etch profile of the etch stop layer.