High-Aspect-Ratio Memory Contacts With Dielectric-Lined Staircases
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Solution Overview
Problem
Conventional memory devices with high-aspect-ratio vertical conductive structures face challenges in forming reliable contacts, as they can degrade or damage other structures within the device, leading to unreliable or defective devices.
Innovation Solution
The use of a combination of dielectric structures and dielectric liners during the formation of conductive contacts at staircase structures in memory devices, which helps mitigate these issues by providing improved contact formation and reducing the impact on other device components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-aspect-ratio vertical conductive structures are formed in conventional memory devices, then electrical contact to control gates is achieved, but other vertical conductive structures or structures in the memory device are degraded or damaged
Solution Approach 1:
A dielectric liner is introduced as an intermediary layer between the conductive contact and the staircase structure. This liner prevents direct contact and potential damage to the control gates while still allowing the conductive contact to function. The dielectric liner acts as a protective mediator that enables the high-aspect-ratio contact to be formed without harming adjacent structures.
Solution Approach 2:
The dielectric liner is formed beforehand on the staircase structure before the conductive contact is deposited. This pre-formed protective layer cushions the staircase structure against potential damage during the contact formation process, preventing degradation of the control gates before the harmful interaction can occur.
2Ease of manufacture
If high-aspect-ratio vertical conductive structures are formed, then conductive paths to control gates are established, but device reliability decreases due to structure degradation
Solution Approach 1:
The dielectric liner serves as a protective intermediary that enables the formation of high-aspect-ratio contacts while preventing damage to adjacent structures. This intermediary layer allows manufacturers to achieve the desired conductive paths without sacrificing device reliability, as it prevents the degradation that would otherwise occur during contact formation.
3Reliability
If dielectric liner and dielectric structure are used during conductive contact formation, then damage to adjacent control gates is prevented, but manufacturing process complexity increases
Solution Approach 1:
The dielectric structure is segmented into multiple components: a dielectric liner layer formed on the staircase structure, and a dielectric structure layer formed over the liner. This segmentation allows each layer to serve a specific protective function, with the liner providing direct protection to the control gates and the dielectric structure providing additional protection and structural support. The segmented approach enables reliable contact formation while organizing the manufacturing process into distinct, manageable steps.
Data Source
AI summary
Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes memory cells located on tiers; control gates for the memory cells and located on respective tiers; a dielectric structure over the control gates; a first conductive contact formed in the dielectric structure and contacting a first control gate, the first conductive contact having a first length; and a second conductive contact formed in the dielectric structure and contacting the second control gate, the second conductive contact having a second length unequal to the first length, wherein the second conductive contact includes a first portion and a second portion, the second portion is between the first portion and the second control gate, the first portion including a first region having a first width, the second portion including a second region having a second width, and the second width being greater than the first width.