3D Memory Stack Column Layout for Step Contact Support
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Solution Overview
Problem
In semiconductor memory devices, the formation of columnar portions using insulating materials can lead to unevenness in the top surface during manufacturing, causing focus errors in lithography and patterning issues due to thermal contraction, and may result in insufficient withstand voltage when nitride layers are involved.
Innovation Solution
The arrangement of columnar portions with different densities and positions relative to contacts and plate-like contacts, using a combination of insulating and semiconductor layers with high Young's modulus, supports the stacked body and prevents subduction while maintaining electrical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If columnar portions are formed using insulating materials to support the stacked body, then the stacked body is supported and subduction is prevented, but unevenness occurs on the top surface causing focus errors in lithography
Solution Approach 1:
The patent applies local quality by forming columnar portions with different structures in different regions: insulating material columnar portions in regions without plate-like contacts, and semiconductor layer columnar portions in regions with plate-like contacts. This localized differentiation resolves the contradiction by providing appropriate support characteristics in each region while maintaining surface flatness through the specific structural design of each columnar portion type.
Solution Approach 2:
The patent uses composite materials by combining insulating materials and semiconductor layers to form different types of columnar portions. The insulating material columnar portions provide mechanical support without causing electrical issues, while the semiconductor layer columnar portions provide both mechanical support and electrical functionality. This composite approach resolves the contradiction between support strength and manufacturing precision.
2Strength
If columnar portions are arranged densely to support the stacked body, then support effectiveness is improved, but thermal contraction causes patterning issues
Solution Approach 1:
The patent applies local quality by differentiating the arrangement and structure of columnar portions based on local requirements: denser insulating material columnar portions in regions without plate-like contacts for maximum support, and appropriately spaced semiconductor layer columnar portions in regions with plate-like contacts to balance support and thermal management. This localized differentiation resolves the contradiction between support effectiveness and patterning reliability.
3Reliability
If nitride layers are used in columnar portions for insulation, then electrical insulation is improved, but withstand voltage becomes insufficient due to thermal contraction
Solution Approach 1:
The patent extracts the nitride layer from the columnar portion structure and replaces it with insulating materials that do not suffer from thermal contraction issues. This extraction resolves the contradiction by removing the harmful thermal contraction effect while maintaining the essential insulation function through alternative materials that provide both insulation and adequate withstand voltage.
Solution Approach 2:
The patent changes the material parameter from nitride layer to insulating materials with different thermal and electrical properties. The insulating materials are selected to have low thermal expansion coefficients and high breakdown voltages, thereby changing the physical parameters to simultaneously achieve good insulation performance and high withstand voltage capability, resolving the contradiction.
4Productivity
If columnar portions are positioned to overlap with contacts for high-density arrangement, then space utilization is improved, but contact risk increases
Solution Approach 1:
The patent applies local quality by differentiating the positioning strategy for different types of columnar portions: insulating material columnar portions are positioned to overlap with contact regions to maximize space utilization without affecting electrical performance, while semiconductor layer columnar portions are positioned to avoid direct overlap with contacts to maintain electrical integrity. This localized positioning strategy resolves the contradiction between space utilization and contact 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 allows for high-density arrangement of columnar portions to support the stacked body, prevent subduction, and maintain electrical performance by positioning them at high contact risk areas and using materials with high Young's modulus to prevent voltage issues.
Implementation Method 1
using a combination of insulating and semiconductor layers with high Young's modulus, supports the stacked body and prevents subduction
Data Source
AI summary
A semiconductor memory device of an embodiment includes: a stacked body including conductive layers stacked apart from each other and having a step portion where the conductive layers are processed in a step-like shape; contacts arranged in the step portion at least on one line in a first direction intersecting with a stacking direction of the stacked body and respectively connected with the conductive layers. A plurality of columnar portions includes first columnar portions having a layer structure different from that of a pillar, and second columnar portions having a same layer structure as that of the pillar. The first columnar portions are arranged on an array at least partially overlapping an array position of the contacts in the first direction. The second columnar portions are arranged on an array away from the array position of the contacts in a second direction intersecting with the stacking direction and the first direction.