Semiconductor Memory Sacrificial Film Thickness Variation
Solution Overview
Problem
Conventional semiconductor memory devices face reliability issues due to uniform sacrificial film thickness, which fails to absorb processing variations in both hole and slit formation, leading to insufficient depth and reduced device reliability.
Innovation Solution
A semiconductor memory device design that forms a sacrificial film with both thick and thin portions to accommodate processing variations, where the slit terminates in the thick portion and the hole penetrates the thin portion, using a conductive layer group and memory film structure to ensure electrical connection and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin sacrificial film is used, then the hole can penetrate the sacrificial film more easily, but the slit cannot terminate properly in the sacrificial film
Solution Approach 1:
The sacrificial film is designed with different thicknesses in different regions: a first sacrificial film with greater thickness for slit termination and a second sacrificial film with smaller thickness for hole penetration. This local quality differentiation allows each structure to interact with the sacrificial film at its optimal thickness level, resolving the contradiction between hole penetration and slit termination requirements
2Reliability
If a thick sacrificial film is used, then the slit can terminate properly in the sacrificial film, but the hole cannot penetrate the sacrificial film effectively
Solution Approach 1:
The sacrificial film structure provides locally optimized thickness: the first sacrificial film region offers sufficient thickness for reliable slit termination, while the second sacrificial film region provides reduced thickness that allows effective hole penetration. This spatial variation in film thickness resolves the contradiction by allowing each process to access the appropriate thickness level
3Ease of manufacture
If a uniform sacrificial film thickness is used, then the manufacturing process is simpler, but processing variations cannot be absorbed for both hole and slit formation
Solution Approach 1:
Instead of uniform thickness, the sacrificial film employs local quality variation with at least two different thickness levels. The first sacrificial film has greater thickness to absorb variations in slit formation, while the second sacrificial film has smaller thickness to absorb variations in hole penetration. This approach maintains manufacturing simplicity while significantly improving reliability through localized thickness optimization
Data Source
AI summary
A semiconductor memory device according to an embodiment includes: a semiconductor substrate; an insulating film provided on the semiconductor substrate; a conductive layer group including at least two conductive layers; a stacked body provided on the conductive layer group and including a plurality of films stacked; a memory film provided in a hole, the hole penetrating the stacked body and a part of the conductive layer group; and a slit splitting the stacked body and terminating at a position deeper than a contact portion between the conductive layer group and the memory film. The conductive layer group has a band-shaped part projecting to the stacked body side at a portion of the hole, and a groove part recessed to the semiconductor substrate side at a portion under the slit.