3D Memory Source Structure Using Variable-Thickness Sacrificial Layers
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Solution Overview
Problem
The existing three-dimensional non-volatile memory elements face challenges in achieving a stable structure and improved reliability, particularly due to the complexity of their manufacturing processes.
Innovation Solution
A semiconductor device is manufactured using a method that involves forming a first sacrificial layer with varying thickness portions, creating a stack of alternating material layers, forming channel and slit structures, and removing the sacrificial layer to form openings for connecting source layers to the channel structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional non-volatile memory elements are designed with vertically stacked memory cells to increase integration density, then storage capacity is improved, but manufacturing process complexity increases
Solution Approach 1:
A sacrificial layer is formed in advance at the source region before forming the channel structure and stack. This preliminary placement of the sacrificial layer simplifies subsequent manufacturing steps by pre-defining the source region boundaries and enabling easier formation of source contacts through later removal of the sacrificial material.
Solution Approach 2:
The sacrificial layer acts as an intermediary element that facilitates the manufacturing process. It is temporarily introduced to define the source region, enable channel structure formation, and is subsequently removed to create source contacts. This intermediary approach simplifies the overall manufacturing complexity by breaking down complex steps into manageable sequential operations.
2Manufacturing precision
If the sacrificial layer is formed with uniform thickness, then manufacturing precision is improved, but the ability to control source region geometry and enable proper channel connection is worsened
Solution Approach 1:
The sacrificial layer is designed with different thicknesses in different regions: a first thickness in the first source region and a second thickness (greater than the first) in the second source region. This local variation in thickness enables different functional requirements to be met in different areas, such as controlling source contact geometry and ensuring proper channel connection while maintaining manufacturing precision through controlled deposition processes.
Data Source
AI summary
A method of manufacturing a semiconductor device according to an embodiment of the present disclosure may include forming a first sacrificial layer including a first portion and a second portion having a thickness thicker than a thickness of the first portion, forming a stack including first material layers and second material layers alternating with each other on the first sacrificial layer, forming a channel structure passing through the stack and extending to the first portion, forming a slit passing through the stack and extending to the second portion, removing the first sacrificial layer through the slit to form a first opening, and forming a second source layer connected to the channel structure in the first opening.