3D Semiconductor Stacked Body Alignment via Universal Mask
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Solution Overview
Problem
Conventional methods for increasing the number of stacked layers in three-dimensional semiconductor memory devices are costly and inefficient due to the need for multiple masks and alignment marks for each story, which complicates the alignment and deviation measurement processes.
Innovation Solution
A semiconductor structure body with alternately stacked conductive and insulating layers, where alignment and deviation measurement marks are formed in specific regions using two types of masks alternately for every other story, reducing the number of masks required and simplifying the alignment and deviation measurement processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods are used to increase the number of stacked layers, then storage capacity is improved, but manufacturing cost increases and working efficiency decreases
Solution Approach 1:
The patent applies universality by using a single mask design that serves multiple functions: it forms both the memory cell patterns and the alignment marks for subsequent stories. This multi-functional mask eliminates the need for separate masks for each story, thereby reducing manufacturing cost while maintaining the ability to increase storage capacity through additional stacked layers.
Solution Approach 2:
The patent merges the formation of memory cell patterns and alignment marks into a single photolithography process step. By combining these previously separate operations into one process using a unified mask design, the patent reduces the total number of masks required and simplifies the manufacturing process, thus lowering costs while enabling higher storage capacity.
2Quantity of substance
If conventional methods are used to increase the number of stacked layers, then storage capacity is improved, but working efficiency decreases
Solution Approach 1:
The universal mask design performs multiple functions simultaneously - creating memory cell structures and alignment references for future layers in one step. This eliminates the need for separate alignment mark formation processes for each story, significantly improving working efficiency while enabling increased storage capacity through additional stacked layers.
Solution Approach 2:
The patent performs preliminary action by forming alignment marks for subsequent stories during the current story's fabrication process. This advance preparation of alignment references eliminates the need for separate alignment mark formation steps later, thereby improving working efficiency while supporting the construction of taller stacked bodies for increased storage capacity.
3Manufacturing precision
If masks are prepared for each story for alignment, then alignment precision is maintained, but device complexity increases
Solution Approach 1:
The patent uses a universal mask that maintains alignment precision by incorporating alignment mark patterns designed specifically for this purpose, while eliminating the complexity of preparing separate masks for each story. The single mask design includes both memory cell patterns and alignment marks, simplifying mask management while preserving alignment accuracy.
Solution Approach 2:
The patent merges the functions of memory cell pattern formation and alignment mark creation into a single mask design. This combination reduces the total number of masks from multiple story-specific masks to a single universal mask, thereby reducing device complexity while maintaining the alignment precision needed for multi-story stacked body construction.
4Manufacturing precision
If masks are prepared for each story for alignment, then alignment between stories is achieved, but the number of masks increases
Solution Approach 1:
The universal mask design achieves alignment between stories by incorporating dedicated alignment mark patterns that work for all stories, eliminating the need for multiple story-specific masks. This single mask approach reduces the number of masks from many to one, while maintaining the alignment precision required for successful multi-story stacking.
Solution Approach 2:
The patent combines the alignment functionality for all stories into a single mask design, merging what would have been multiple separate alignment operations into one unified process. This reduces the mask count significantly while preserving the alignment accuracy needed for constructing multi-story stacked bodies with high storage capacity.
Data Source
AI summary
A semiconductor structure body of an embodiment includes a stacked body. In the stacked body, a plurality of conductive layers and a plurality of insulating layers are alternately stacked, and a plurality of through holes penetrating the conductive layers and the insulating layers in the stacking direction are provided. In the interior of the stacked body, in a region corresponding to an identical pair of coordinates in a planar coordinate system intersecting the stacking direction, a plurality of identical alignment marks or deviation measurement marks are formed, with one or more stories each including a predetermined number of conductive layers and a predetermined number of insulating layers interposed therebetween.