Ion-Implanted Cladding for Deep Via Etching in 3D Memory
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Solution Overview
Problem
Current methods for forming three-dimensional memory devices face challenges in creating deep via openings with precise control and high etch resistance, leading to inefficiencies in the formation of complex semiconductor structures.
Innovation Solution
A method involving the formation of an alternating stack of material layers, followed by the use of a composite hard mask and non-conformal cladding liner, where ions are implanted to enhance etch resistance, allowing for anisotropic etching processes that vertically extend via openings with improved precision and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional etching methods are used to form deep via openings, then via depth can be achieved, but etch resistance and precision control deteriorate
Solution Approach 1:
The patent employs a composite hard mask structure consisting of multiple material layers (e.g., silicon nitride, silicon oxide, carbon-based materials) with different etch resistance properties. This composite approach allows the mask to provide sufficient etch resistance for deep via formation while maintaining precise pattern transfer control throughout the etching process.
Solution Approach 2:
The hard mask is divided into multiple segmented layers, each with optimized thickness and material composition. This segmentation enables differential etch resistance at various depths, allowing precise control of the etching process while achieving the required via depth.
2Length of stationary object
If conventional etching methods are used to form deep via openings, then via depth can be achieved, but precision control deteriorates
Solution Approach 1:
The patent performs preliminary actions by forming a detailed multi-layer hard mask structure before the actual deep via etching. This pre-formed composite mask system is designed to maintain its structural integrity and pattern definition throughout the deep etching process, ensuring precision control is preserved from the beginning of the etch operation.
Solution Approach 2:
The patent utilizes parameter changes in the mask layer composition and thickness to optimize etch selectivity and control. By adjusting the material parameters and layer dimensions of the composite hard mask, the process achieves both deep via formation and precise dimensional control.
3Device complexity
If simple mask structures are used, then process complexity is reduced, but etch resistance is insufficient for deep vias
Solution Approach 1:
The patent implements a composite hard mask structure with multiple material layers including silicon nitride, silicon oxide, and carbon-based materials. Each layer contributes specific etch resistance properties, collectively providing sufficient protection during deep via etching while maintaining a manageable process complexity through standardized deposition techniques.
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 enables the formation of complex semiconductor structures with precise deep via openings, enhancing the fabrication of three-dimensional memory devices by improving etch resistance and reducing structural irregularities.
Implementation Method 1
The non-conformal cladding liner provides a higher etch resistance relative to the lower portions of the alternating stack after the step of implanting ions than before the step of implanting ions
Implementation Method 2
implanting ions of dopant atoms into the non-conformal cladding line
Implementation Method 3
performing a second anisotropic etch process that etches unmasked lower portions of the alternating stack selective to the etch mask material layer and the non-conformal cladding liner
Data Source
AI summary
A method includes forming an alternating stack of first material layers and second material layers, forming an etch mask material layer containing an opening over the alternating stack, forming a non-conformal cladding liner over the etch mask material layer, where the non-conformal cladding liner includes a horizontally extending portion that overlies a horizontal top surface of the etch mask material layer and a vertically extending portion contacting a sidewall of the opening in the etch mask material layer, implanting ions of dopant atoms into the non-conformal cladding line, and performing an second anisotropic etch process that etches an unmasked portion of the alternating stack selective to the etch mask material layer and the non-conformal cladding liner. The non-conformal cladding liner provides a higher etch resistance relative to the unmasked portion of the alternating stack after the step of implanting ions than before the step of implanting ions.