Semiconductor Etch Selectivity via Isotropic Plasma Bonding Modification
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in achieving high etch selectivity and controlling the profile of deposition films on stepped structures with high aspect ratios, particularly in three-dimensional semiconductor devices, where traditional methods often require lithography and struggle to pattern films effectively without directional plasma.
Innovation Solution
A substrate processing method involving alternating plasma treatments in different atmospheres to form and modify the bonding structure of deposition films, allowing for isotropic etching without lithography, where a first operation with low-directional plasma ions forms a conformal film and a second operation with directional plasma ions changes the film's bonding structure, enabling selective etching and profile control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional lithography and directional plasma etching are used, then pattern precision is improved, but device complexity and process steps increase
Solution Approach 1:
The invention extracts and removes the lithography step from the traditional manufacturing process by using selective isotropic etching to directly pattern the deposition film, thereby simplifying the overall process while maintaining pattern precision
Solution Approach 2:
The invention changes the plasma etching parameters from directional (anisotropic) to isotropic conditions, and controls pressure and gas composition to achieve selective etching that patterns the film without requiring lithography, thus reducing process complexity
2Productivity
If isotropic etching is performed on a deposition film, then lithography steps are reduced, but etch selectivity between different film regions deteriorates
Solution Approach 1:
The invention applies preliminary plasma treatment to modify the bonding structure of the deposition film before isotropic etching, creating regions with different etch resistance that enable selective etching while maintaining process efficiency
Solution Approach 2:
The invention changes pressure and gas composition parameters during plasma treatment to control the bonding structure modification, enabling selective etching with isotropic conditions by creating chemical differences between film regions
3Shape
If plasma ions have directionality to control film profile, then film shape control is improved, but etch selectivity between top/bottom and side surfaces deteriorates
Solution Approach 1:
The invention inverts the conventional approach by using isotropic (non-directional) plasma etching combined with preliminary bonding structure modification to achieve selective etching, rather than relying on directional plasma to control shape, thus improving etch selectivity
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 method enhances etch selectivity and allows for precise control of film profiles on stepped structures, improving the patterning process by selectively removing films from top and bottom surfaces while maintaining them on side surfaces, thus avoiding the need for additional photolithography steps.
Implementation Method 1
a first operation for forming a film on a stepped structure having a top surface, a bottom surface, and a side surface connecting the top surface and the bottom surface, wherein a first atmosphere is set to reduce a mean free path of plasma ions and to cause the plasma ions to have no directionality
Implementation Method 2
a second operation for changing a bonding structure of a portion of the film, wherein a second atmosphere is set to cause the plasma ions to have directionality, wherein during the second operation, the bonding structure of the portion of the film may be weakened by an ion bombardment effect of the plasma ions
Implementation Method 3
performing isotropic etching on a film formed by performing the group cycle a plurality of times
Data Source
AI summary
A substrate processing method with an improved etch selectivity includes: a first operation for forming a film on a stepped structure having a top surface, a bottom surface, and a side surface connecting the top surface and the bottom surface, wherein a first atmosphere is set to reduce a mean free path of plasma ions and to cause the plasma ions to have no directionality; and a second operation for changing a bonding structure of a portion of the film, wherein a second atmosphere is set to cause the plasma ions to have directionality, wherein the first operation is repeated a plurality of times, the second operation is performed for a predetermined time period, the first operation and the second operation form a group cycle, and the group cycle is repeated by a plurality of times.