Staircase Semiconductor Stacked Body Insulating Film
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Solution Overview
Problem
In semiconductor memory devices with three-dimensional structures, the increase in the number of stacked electrode films leads to poor reliability due to contact punch-through issues in shallow holes, causing short circuits and misalignment of contact holes in the staircase-shaped end parts of the stacked body.
Innovation Solution
The semiconductor device incorporates an insulating film 50 with an inclination extending along the staircase-shaped end part of the stacked body, which functions as a film to stop etching and prevent punch-through, ensuring reliable contact formation by maintaining a consistent etching selection ratio and preventing misalignment of contact holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked electrode films is increased to achieve higher integration, then the memory capacity is improved, but contact punch-through occurs in shallow holes causing poor reliability
Solution Approach 1:
The patent divides the end part of the stacked body into multiple terraces at different heights, with each terrace corresponding to a specific electrode film. This segmentation allows contacts to be formed at different vertical positions, preventing punch-through by ensuring that contacts to upper electrode films do not extend too deeply and cause short circuits to lower electrode films.
Solution Approach 2:
The patent introduces a vertical height dimension to the end part structure by creating a staircase configuration with multiple terraces at different heights. This dimensional change allows the contact holes to be naturally depth-limited by the terrace structure, solving the punch-through problem without requiring additional process steps or materials.
2Ease of manufacture
If the end part is processed into a staircase shape to enable contact formation, then electrode extraction is facilitated, but contact holes may misalign or punch through causing short circuits
Solution Approach 1:
The staircase structure with terraces is formed beforehand before contact hole formation. This preliminary action creates pre-defined stopping points at each terrace level, which guide the etching process and ensure that contact holes automatically stop at the correct depth without requiring complex control mechanisms, thereby preventing misalignment and punch-through.
Solution Approach 2:
The terrace structure acts as an intermediary element between the stacked body and the contact holes. It provides a physical reference level that mediates the etching process, ensuring that contact holes are formed at the correct depth and position without requiring additional alignment marks or complex process control.
Data Source
AI summary
According to an embodiment, a semiconductor device includes a substrate, a stacked body, a first insulating film, a second insulating film and a plurality of contacts. The stacked body is provided on the substrate and includes a plurality of electrode films stacked with spacing from each other. An end part of the stacked body is shaped like a staircase in which a terrace is formed in each of the plurality of electrode films. The first insulating film is provided on the end part. The second insulating film is provided on the first insulating film and located along the end part. At least part of the second insulating film extends with inclination. The plurality of contacts extends in a stacking direction of the plurality of electrode films in the first insulating film and the second insulating film and is located on the terraces of the plurality of electrode films.