Semiconductor Memory Device Dummy Plugs for Optical Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reliability of three-dimensional semiconductor memory devices is compromised as the number of stack layers increases, leading to reduced integration and performance.
Innovation Solution
A semiconductor memory device design featuring a stack body with lower, upper, and intermediate conductive patterns, along with contact plugs and dummy plugs, which alleviates the issue of optical distortion during photolithography, ensuring stable connections and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stack layers of memory cells is increased to improve the degree of integration, then the degree of integration is improved, but the reliability of the three-dimensional semiconductor memory device is reduced
Solution Approach 1:
The patent introduces dummy plugs (first dummy plugs and second dummy plugs) that are formed in advance alongside the contact plugs. These dummy plugs serve as preliminary structures that compensate for optical distortion effects during the photolithography process, ensuring that the actual contact plugs maintain their intended dimensions and positions even when stack layers are increased for higher integration.
Solution Approach 2:
The dummy plugs act as intermediary elements that absorb the harmful optical distortion effects. By placing these dummy structures adjacent to the contact plugs, they serve as mediators that protect the contact plugs from dimensional variations caused by optical distortion, thereby maintaining connection reliability despite increased stack layer counts.
2Quantity of substance
If the number of stack layers is increased, then the degree of integration is improved, but manufacturing precision is reduced due to optical distortion
Solution Approach 1:
The patent converts the harmful optical distortion effect into a beneficial outcome by strategically placing dummy plugs in regions where optical distortion occurs. These dummy structures experience the distortion themselves, allowing the actual contact plugs to maintain their precise dimensions and positions. The harmful optical distortion is thus transformed into a controlled effect that does not compromise manufacturing precision.
Solution Approach 2:
The dummy plugs are created as copies or replicas of the contact plug structures. By forming these duplicate structures alongside the actual contact plugs, the patent creates reference structures that experience the same optical distortion, thereby enabling the contact plugs to maintain their intended geometric properties despite the distortion effects during photolithography.
3Reliability
If contact plugs are formed to connect conductive patterns, then connections are established, but optical distortion during photolithography causes connection defects
Solution Approach 1:
The dummy plugs are formed in advance as preliminary structures during the same photolithography process that forms the contact plugs. These preliminary dummy structures are positioned adjacent to the contact plugs and serve as reference elements that compensate for optical distortion, ensuring that the contact plugs achieve their intended dimensions and positions for reliable connections.
Solution Approach 2:
The dummy plugs serve as intermediary reference structures that protect the contact plugs from optical distortion effects. By positioning these dummy plugs adjacent to the contact plugs, they act as mediators that absorb the distortion effects, allowing the contact plugs to maintain their precise geometric properties and ensure defect-free connections between conductive patterns.
Data Source
AI summary
A semiconductor memory device according to the present technology includes a stack body including a lower conductive pattern and an upper conductive pattern stacked apart from each other in a first direction, and at least one intermediate conductive pattern disposed between the lower conductive pattern and the upper conductive pattern, a contact plug connected to the lower conductive pattern and extending in the first direction, and at least one lower dummy plug overlapping the lower conductive pattern.