Semiconductor Structure Composite Film Etch Stop and Blocking Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in reducing the number of malfunctioning devices per manufactured wafer during the down-scaling of transistors, which requires advanced etching processes to maintain performance and prevent undesirable etching and tunneling effects in metal gate electrode formation.
Innovation Solution
A composite film structure is introduced, comprising etch stop layers resistant to etching and blocking layers with higher bandgaps to prevent unwanted etching and electron tunneling, which are alternately stacked to protect semiconductor features and reduce electrical communication paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If advanced etching processes are used to maintain performance during down-scaling, then transistor performance is improved, but undesirable etching and tunneling effects increase
Solution Approach 1:
A composite film structure comprising an etch stop layer and a blocking layer is introduced as an intermediary between the etching process and the metal gate electrode. The etch stop layer selectively resists etching to protect underlying features, while the blocking layer with higher bandgap prevents electron tunneling, thus resolving the harmful effects while maintaining manufacturing precision
Solution Approach 2:
The patent employs a composite film structure combining two different materials with distinct properties: an etch stop layer material resistant to specific etchants and a blocking layer material with higher bandgap energy. This composite structure simultaneously addresses both etching protection and tunneling prevention, resolving the technical contradiction
2Reliability
If metal gate electrodes are formed using gate last process, then device performance is improved, but the number of malfunctioning devices increases due to processing complexity
Solution Approach 1:
The composite film structure divides the protection function into two separate layers: an etch stop layer for etching protection and a blocking layer for tunneling prevention. This segmentation allows each layer to be optimized for its specific function, simplifying the overall processing while maintaining device performance and reliability
3Object-affected harmful factors
If composite film structure with etch stop layers and blocking layers is used, then undesirable etching and tunneling are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the etch stop layer and blocking layer into a single composite film structure that can be deposited and processed together. This combining approach reduces the number of separate processing steps compared to treating the layers independently, thus reducing manufacturing complexity while effectively preventing both etching and tunneling
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 solution effectively reduces undesirable etching and electron tunneling, leading to improved device yields, increased breakdown voltage, and lower manufacturing costs by using nitrides and oxides in the composite film structure.
Implementation Method 1
blocking layers with higher bandgaps to prevent unwanted etching and electron tunneling
Data Source
AI summary
A semiconductor structure includes a substrate, a gate region, a source/drain region, a composite layer, an ILD layer, a first plug and a second plug. The composite layer includes a first sublayer and a third layer including a first material, and a second sublayer including a second material. The second sublayer is between the first sublayer and the third sublayer. The first plug is through the ILD layer and electrically connected to the gate region. The second plug is through the ILD layer and the composite layer and electrically connected to the source/drain region. The second plug includes a first portion laterally adjoining the first sublayer, a second portion laterally adjoining the second sublayer, and a third portion laterally adjoining the third sublayer. Widths of the first portion and the third portion are smaller than a width of the second portion. The second portion has a substantially curved sidewall profile.