Semiconductor Device Contact Hole Alignment via Conductive Layer Extensions
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Solution Overview
Problem
As semiconductor devices become more densely integrated and smaller in size, the reduced thickness and distance between conductive layers make it difficult to form contact holes accurately, leading to electrical leakage due to misalignment.
Innovation Solution
A semiconductor device structure and manufacturing method where contact holes are formed between overlapping portions of conductive layers, ensuring precise alignment and preventing electrical leakage by maintaining the contact hole within the correct overlapping regions, with conductive layers having specific shapes and extensions to facilitate accurate etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of conductive layers or the distance between conductive layers is reduced to increase integration density, then the integration density and storage capacity are improved, but the difficulty of forming contact holes accurately increases and electrical leakage occurs due to misalignment
Solution Approach 1:
The patent applies preliminary action by forming extension portions on conductive layers before contact hole formation. These extension portions protrude beyond the main body of the conductive layers and serve as pre-positioned alignment guides. During subsequent processing steps, the contact holes are formed by aligning with these extension portions, which ensures accurate positioning even when layer thicknesses are reduced for higher integration density. This preliminary structural preparation prevents misalignment and electrical leakage while maintaining the benefits of reduced layer dimensions.
2Length of stationary object
If the thickness of conductive layers is reduced to improve integration, then the device size and distance between layers are improved, but the formation of contact holes becomes more difficult and misalignment occurs
Solution Approach 1:
The patent introduces extension portions as intermediary structures that mediate between the reduced-thickness conductive layers and the contact hole formation process. These extension portions act as intermediate alignment references that are easier to locate and align with than the thin conductive layers themselves. By providing these intermediary structural features, the patent makes contact hole formation easier and more reliable even when the distance between conductive layers is reduced for higher integration.
3Productivity
If contact holes are formed in reduced-thickness structures, then the integration density is improved, but electrical leakage occurs due to misalignment with conductive layers
Solution Approach 1:
The extension portions are formed in advance as preliminary alignment structures that guide contact hole positioning. This preliminary action ensures that contact holes are accurately positioned to connect only the intended conductive layers, preventing misalignment and electrical leakage. The extension portions serve as pre-established reference features that maintain reliability even in high-density integrated structures where misalignment risks are elevated.
Solution Approach 2:
The patent converts the potential harm of reduced layer thickness (which makes alignment more difficult and increases leakage risk) into a benefit by using the extension portions as positive alignment features. Instead of trying to directly align with the thin conductive layers, the extension portions provide robust, easily locatable reference structures that actually improve alignment accuracy. The reduced thickness challenge is transformed into an opportunity to use extension portions as precise positioning guides, thereby preventing leakage while maintaining high integration density.
Data Source
AI summary
A semiconductor device capable of reducing electrical leakage generated when a contact hole is misaligned and a manufacturing method thereof is disclosed. The semiconductor device includes three conductive layers with various and different portions overlapping each other. The conductive layers are separated by insulating layers and connected by contact holes formed in the insulating layers between the overlapping potions. Thus, electric leakage, caused by misalignment when forming the contact hole to electrically connect the conductive layers to each other, can be prevented.