Semiconductor Pillar V-Shape Etching Cavity Prevention
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Solution Overview
Problem
During the manufacturing of three-dimensional stacked semiconductor memory devices, the formation of pillar portions with embedded films can result in cavities (seams) due to outwardly curved holes or grooves, which compromises the structural integrity and film forming properties of the semiconductor device.
Innovation Solution
The semiconductor device incorporates a pillar portion with a first film composed of silicon and a second film, where the composition rate of the second material (such as germanium) decreases from the upper part to the lower part, allowing for controlled etching and formation of a V-shaped section, preventing cavity formation by ensuring the upper part of the electrically conducting film is removed before embedding the amorphous silicon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a film is embedded in a hole or groove with an outwardly curved middle part, then the pillar portion can be formed, but a cavity (seam) occurs in the pillar portion
Solution Approach 1:
The patent applies preliminary action by forming a V-shaped section at the upper part of the pillar portion before embedding the film material. This V-shaped section is created by selectively removing material to form a tapered structure that prevents cavity formation during subsequent film embedding processes, ensuring the film adheres properly without creating seams or voids.
Solution Approach 2:
The patent changes the geometric parameters of the pillar portion by introducing a V-shaped section with specific angle and depth parameters. This parameter modification alters the surface topology from a simple cylindrical hole to a tapered structure, which fundamentally changes how the film material behaves during embedding and prevents cavity formation.
2Shape
If the hole or groove is curved outward in the middle part, then the pillar portion structure is formed, but the film forming properties deteriorate
Solution Approach 1:
The V-shaped section is formed as a preliminary structure before film deposition. This pre-formed geometric feature ensures that when the film is subsequently deposited, it follows the tapered contour and adheres properly, preventing the formation of cavities or seams that would otherwise occur in a straight-walled hole.
Solution Approach 2:
The patent applies local quality by creating a V-shaped section only at the upper part of the pillar portion where the curvature issue occurs, while the lower part maintains its original structure. This localized geometric modification addresses the specific film forming problem without altering the entire pillar structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the film forming properties of the semiconductor device by preventing cavity formation and improving the structural integrity of the pillar portion, ensuring a seamless integration of films and maintaining the device's performance.
Implementation Method 1
The second material is a material that increases an etching rate of the first material as a composition rate relative to the first material increases
Data Source
AI summary
A semiconductor device according to one embodiment is provided with: a substrate; a stacked body provided on the substrate; and a pillar portion penetrating the stacked body. The pillar portion has a first film including a first material and a second material, and a second film provided on an inner side of the first film. The second material is a material that increases an etching rate of the first material as a composition rate relative to the first material is higher, and the composition rate gradually decreases from an upper part to a lower part of the first film.