Contact Plug Structure for 3D Memory Contact Resistance
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Solution Overview
Problem
In three-dimensional semiconductor memory devices, the miniaturization of contact diameters leads to increased contact resistance between contacts and conductive layers, which hinders further capacity enhancement and efficiency.
Innovation Solution
The semiconductor memory device employs a contact plug structure with a first member extending in the laminating direction and a second member intersecting the laminating direction, embedded within void portions of the conductive layers, to increase the contact area and reduce resistance variations among conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If contact diameter is reduced for miniaturization, then device capacity is enhanced, but contact resistance increases
Solution Approach 1:
The contact plug structure transitions from a simple vertical contact to a three-dimensional configuration with a second member extending in a direction intersecting the laminating direction. This dimensional expansion increases the contact area with the conductive layer without increasing the vertical height, thereby reducing contact resistance while maintaining miniaturization benefits.
Solution Approach 2:
The contact plug is divided into two functional members: a first member extending in the laminating direction that provides vertical electrical connection, and a second member extending in an intersecting direction that increases lateral contact area with the conductive layer. This segmentation allows each member to optimize its function while collectively reducing contact resistance.
2Length of moving object
If contact diameter is reduced, then device size is miniaturized, but resistance variations among conductive layers increase
Solution Approach 1:
By extending the contact plug in an additional dimension (the second member in the intersecting direction), the contact interface is expanded from a point-like or small circular area to a larger three-dimensional contact zone. This increased contact area averages out local variations in conductive layer properties, reducing resistance variations among different conductive layers.
Solution Approach 2:
The first and second members of the contact plug are merged into a single integrated structure that simultaneously provides vertical connection and lateral contact expansion. This unified structure ensures consistent electrical connection across multiple conductive layers, minimizing resistance variations while maintaining compact dimensions.
Data Source
AI summary
According to an embodiment, a semiconductor memory device includes a plurality of first conductive layers disposed above a substrate in a laminating direction. A stepped wiring area includes a second conductive layer electrically connected to the first conductive layer. The second conductive layer has an end portion as a contact connection portion. A contact plug is connected to the contact connection portion. The contact plug extends in the laminating direction. The contact plug includes a first member and a second member. The first member extends in the laminating direction. The second member extends in a direction intersecting with the laminating direction inside the contact connection portion.