Memory Stack Stadium Structure With Widened Steps for Reliable Contacts
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Solution Overview
Problem
Conventional microelectronic device fabrication methods for vertical memory arrays result in undesirable defects, diminishing memory device performance, reliability, and durability due to increased feature packing densities and reduced margins for formation errors.
Innovation Solution
The implementation of stadium structures within the stack structure of microelectronic devices, featuring alternating conductive and insulative tiers with widened steps in the upper stadium structure to accommodate larger conductive contact structures, reducing electrical shorting risks and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature packing density is increased to improve memory device integration, then memory device density is improved, but manufacturing precision deteriorates due to reduced margins for formation errors
Solution Approach 1:
The patent divides the contact structure formation process into multiple discrete steps: forming individual contact holes through the insulative material, depositing conductive material in each contact hole, and creating separated contact structures. This segmentation allows each contact structure to be formed with precise control, maintaining manufacturing precision even as overall device density increases through higher packing of these individually-formed contacts.
2Device complexity
If conventional staircase structures are used to provide electrical access, then device complexity is reduced, but reliability deteriorates due to electrical shorting defects
Solution Approach 1:
The patent introduces an intermediate insulative material layer that fills the spaces between adjacent contact structures and extends over the top surfaces. This intermediate layer acts as a mediator that physically separates the conductive contact structures, preventing electrical shorting while still allowing the structure to maintain relatively simple fabrication processes. The insulative material serves as a buffer that eliminates direct contact between adjacent conductive elements.
3Quantity of substance
If feature dimensions are reduced to improve miniaturization, then memory device density is improved, but durability deteriorates due to increased susceptibility to formation errors
Solution Approach 1:
The patent performs preliminary formation of each contact structure individually before assembling the complete device. Contact holes are formed through the insulative material, conductive material is deposited in each hole, and the insulative material is filled between them in advance. This preliminary, step-by-step formation ensures that each miniaturized feature is properly formed with adequate margins, improving durability while maintaining high density through the compact final arrangement.
Data Source
AI summary
A microelectronic device includes a stack structure having tiers each including conductive material vertically neighboring insulative material and conductive contact structures. The stack structure is divided into blocks horizontally extending in parallel in a first direction and separated from one another in a second direction orthogonal to the first direction by insulative slot structures. At least one of the blocks includes a lower stadium structure having steps including edges of some of the tiers, and an upper stadium structure vertically overlying the lower stadium structure and having additional steps including edges of some other of the tiers vertically overlying the some of the tiers. The additional steps have greater tread widths in the first direction than the steps. Conductive contact structures are in contact with the additional steps of the upper stadium structure of the at least one of the blocks. Memory devices and electronic systems are also described.