DRAM Capacitor Hole Patterning for Uniform Etch Depth
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Solution Overview
Problem
The manufacturing process of semiconductor structures, particularly DRAM capacitor holes, faces challenges such as depth differences and size variations due to increased integration levels and reduced feature sizes, leading to issues like insufficient etching and interconnection problems.
Innovation Solution
A method involving a stack formation with sacrificial and supporting layers, followed by the creation of intersecting etching patterns in the first and second mask layers to form capacitor holes, ensuring the bottom of the etching holes is flat and the depths of the capacitor holes are uniform, using techniques like chemical vapor deposition and dry etching to achieve precise patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the integration level of DRAM is continuously improved and the transverse dimension of elements is continuously reduced, then the capacitor has higher aspect ratio and higher density, but the manufacturing process becomes increasingly difficult and depth difference of capacitor holes occurs
Solution Approach 1:
The patent divides the single etching process into two sequential etching steps with different mask patterns. The first etching step forms preliminary holes using a first mask layer, and the second etching step completes the capacitor holes using a second mask layer. This segmentation allows each etching step to be optimized independently, improving depth uniformity while managing process complexity through systematic division of the manufacturing process.
Solution Approach 2:
The first mask layer and first etching step are performed as preliminary actions before the final capacitor hole formation. This preliminary etching creates initial holes that guide the subsequent second etching step, ensuring that the final capacitor holes achieve uniform depth and proper positioning. The preliminary action establishes a foundation that simplifies the final etching operation.
2Length of moving object
If the transverse dimension of elements is continuously reduced, then the capacitor has higher aspect ratio, but phenomena of interconnection of capacitor tubes and insufficient etching are liable to occur
Solution Approach 1:
The etching process is segmented into two distinct steps with different mask patterns. The first etching step creates preliminary holes with controlled depth, and the second etching step completes the holes to the final depth. This segmentation prevents insufficient etching by ensuring each step contributes to the overall etching completeness, while the separated steps reduce the risk of interconnection by providing better control over hole formation at each stage.
Solution Approach 2:
The patent introduces a temporal dimension by performing etching in two sequential steps rather than one simultaneous step. This dimensional change in the process flow allows for better control over the etching depth and uniformity, ensuring complete etching without interconnection even as the capacitor aspect ratio increases due to reduced transverse dimensions.
3Quantity of substance
If the capacitor has higher aspect ratio due to reduced transverse dimension, then the density is higher, but size difference of capacitor tubes and depth difference of capacitor holes are liable to occur
Solution Approach 1:
The manufacturing process is segmented into two etching steps with different mask patterns to achieve uniform capacitor hole dimensions. The first mask layer defines preliminary hole positions, and the second mask layer refines the final hole dimensions. This segmentation allows precise control over both the position and size of capacitor holes, ensuring size uniformity even as integration density increases through reduced transverse dimensions and higher aspect ratios.
Solution Approach 2:
The first mask layer and first etching step serve as preliminary actions that establish the foundation for uniform capacitor hole formation. By pre-defining hole positions and preliminary dimensions, the first step ensures that subsequent processing results in uniform final dimensions. This preliminary action is crucial for maintaining size uniformity when manufacturing high-density DRAM with high aspect ratio capacitors.
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 ensures the formation of capacitor holes with consistent depths and sizes, reducing material accumulation and bulge formation, thereby improving the manufacturing process and preventing interconnection issues in semiconductor structures.
Implementation Method 1
using techniques like chemical vapor deposition and dry etching to achieve precise patterning
Implementation Method 2
using techniques like chemical vapor deposition and dry etching to achieve precise patterning
Data Source
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AI summary
An embodiment of the present application belongs to the technical field of storage device manufacturing, relates to a method for manufacturing a semiconductor structure and a semiconductor structure, which are used to solve the technical problem of depth difference of capacitor holes of the semiconductor structure in the related art. The method for manufacturing a semiconductor structure includes: a first mask layer is formed on a dielectric layer, in which a first etching hole extending along a first direction parallel to the dielectric layer is formed in the first mask layer; a side of the first mask layer away from the dielectric layer is planarized; a second mask layer is formed on the first mask layer, in which a second etching hole extending along a second direction parallel to the dielectric layer is formed in the second mask layer, the first etching hole and the second etching hole constitute an etching hole; and the dielectric layer is etched along the etching hole to form the capacitor hole. A side of the first mask layer away from the dielectric layer is planarized, so that impurity residue on the first mask layer is avoided, the bottom of the second etching hole is flat, and the depths of the capacitor holes are the same when the capacitor hole is formed.