Notched Gate Electrode Layout for DI Region Alignment
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Solution Overview
Problem
The challenge in integrated circuit manufacturing is the difficulty in accurately aligning gate electrodes with Device Isolation (DI) regions, leading to potential leakage currents between source and drain regions due to the imprecision in overlaying these components.
Innovation Solution
The formation of notches in the gate electrode layer, which serve as alignment marks, allows for improved overlay accuracy during the manufacturing process by using these notches to guide subsequent process steps, such as implantation of DI regions and patterning of gate electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Device Isolation regions are formed by implantation to replace Shallow Trench Isolation regions, then surface damage is reduced, but alignment accuracy between gate electrodes and DI regions deteriorates
Solution Approach 1:
Alignment marks are formed on the substrate before the implantation process. These pre-formed marks serve as reference features that guide the subsequent formation of DI regions and gate electrodes, ensuring accurate alignment without requiring the implantation process itself to create alignment features.
Solution Approach 2:
Alignment marks act as an intermediary element between the substrate and the implantation process. These marks provide a visual or detectable reference that mediates the alignment between different manufacturing steps, allowing precise positioning of DI regions relative to gate electrodes without direct dependency on implantation precision alone.
2Device complexity
If gate electrodes are misaligned to DI regions due to overlay difficulties, then manufacturing complexity is reduced, but device performance deteriorates due to leakage currents
Solution Approach 1:
Alignment marks are created in advance to guide the formation of gate electrodes and DI regions. This preliminary structuring enables precise alignment during subsequent manufacturing steps, ensuring proper separation between source and drain regions while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The alignment marks serve as an intermediary reference system that facilitates accurate overlay between gate electrodes and DI regions. This intermediary structure enables manufacturers to achieve high alignment precision without significantly increasing process complexity, thereby preventing leakage currents and maintaining device reliability.
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 approach enhances the accuracy of component alignment in integrated circuit manufacturing, reduces surface damage, and effectively eliminates source-to-drain leakage, thereby improving the performance and capacity of image sensor chips.
Implementation Method 1
The DI regions are formed by implanting an impurity to portions of a substrate
Data Source
AI summary
A device includes a semiconductor substrate, a gate dielectric over the semiconductor substrate, and a gate electrode over the gate dielectric. The gate electrode has a first portion having a first thickness, and a second portion having a second thickness smaller than the first thickness. The device further includes a source/drain region on a side of the gate electrode with the source/drain region extending into the semiconductor substrate, and a device isolation region. The device isolation region has a part having a sidewall contacting a second sidewall of the source/drain region to form an interface. The interface is overlapped by a joining line of the firs portion and the second portion of the gate electrode.