Memory Structure Spacer Conductive Layer Contact Process Window
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Solution Overview
Problem
As semiconductor device dimensions shrink, the process window for forming contacts connected to select gates in non-volatile memory structures decreases, making it difficult to accurately connect contacts to the select gate of the spacer form.
Innovation Solution
A memory structure is designed with a stacked gate structure that includes a control gate, a first spacer conductive layer with merged and non-merged spacer portions, where the merged spacer portion has a larger line width, allowing for a larger process window when connecting contacts to the merged spacer portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If semiconductor device dimensions are shrunk to increase integration density, then device capacity and miniaturization are improved, but the process window for contact formation decreases making accurate connection difficult
Solution Approach 1:
The spacer conductive layer is divided into two distinct portions: a merged spacer portion with larger line width and a non-merged spacer portion with smaller line width. This segmentation allows the contact to connect to the wider merged portion which provides a larger process window, while the narrower non-merged portion maintains the overall miniaturization benefits for other device regions.
Solution Approach 2:
Different regions of the spacer conductive layer are given different line widths to serve different functions. The merged spacer portion has a larger line width specifically at the contact connection region to provide manufacturing tolerance, while other regions maintain smaller dimensions for device density. This local variation in geometric quality resolves the contradiction between miniaturization and manufacturability.
2Device complexity
If contact is connected to the slope of the select gate of spacer form, then device structure is simplified, but the process window for contact formation becomes very small
Solution Approach 1:
The spacer conductive layer is segmented into a merged portion and a non-merged portion. The merged portion creates a broader connection area that is less sensitive to alignment variations during contact formation, thereby increasing the process window while maintaining the overall simplified spacer-based contact structure.
Solution Approach 2:
Instead of relying solely on the lateral slope geometry for contact connection, the invention introduces a vertical dimension variation by merging the spacer portions. This creates a three-dimensional structure where the contact can connect to a wider region at a specific height, adding a dimensional degree of freedom that enlarges the process window.
Data Source
AI summary
A memory structure including a substrate, at least one stacked gate structure, a first spacer conductive layer, and a first contact is provided. The stacked gate structure is located on the substrate and includes a control gate. The control gate extends in a first direction. The first spacer conductive layer is located on one sidewall of the control gate and is electrically insulated from the control gate. The first spacer conductive layer includes a first merged spacer portion and a first non-merged spacer portion. A line width of the first merged spacer portion is greater than a line width of the first non-merged spacer portion. The first contact is connected to the first merged spacer portion. The memory structure can have a larger process window of contact.