Semiconductor Hard Mask Etching for Fine Pattern Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional double patterning technologies for semiconductor manufacturing, such as LELE processes, face challenges with feature damage and etching nonuniformity, leading to low yield and resolution limitations in creating fine patterns beyond photolithographic capabilities.
Innovation Solution
A method involving the sequential formation of target and hard mask layers, with specific etching processes and material selections, including anisotropic etching and the use of patterned organic layers, to create precise patterns in semiconductor structures, enhancing pattern transfer and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LELE processes are used for double patterning, then fine patterns can be fabricated beyond photolithographic resolution limits, but features are easily damaged and yield is low
Solution Approach 1:
The patent divides the patterning process into multiple sequential steps with distinct functions: first forming a mandrel pattern, then using it to define trenches for a second material layer. This segmentation allows each step to be optimized independently, reducing cumulative damage while achieving fine pitch patterns that exceed single lithography resolution limits
Solution Approach 2:
The patent introduces a mandrel structure as an intermediary element that mediates the pattern transfer process. The mandrel serves as a template that defines the trench locations, allowing the second material to be deposited and patterned without direct exposure to the full stress of multiple lithography cycles, thereby protecting feature integrity
2Ease of manufacture
If photolithographic processes are used for fabricating semiconductor features, then manufacturing is straightforward, but resolution is limited
Solution Approach 1:
The patent transitions from a planar single-layer lithography approach to a three-dimensional multi-layer structure. By adding vertical dimensionality with stacked materials (mandrel, trench, second material) and using the mandrel's height and width as independent control parameters, the process achieves fine pitch patterns that cannot be obtained with conventional two-dimensional photolithography alone
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 improves pattern precision, reduces damage, and achieves better etching uniformity, resulting in finer critical dimensions and higher yield with uniform patterns.
Implementation Method 1
etching the exposed portion of the upper hard mask layer to form a first patterned upper hard mask layer comprising at least one recess and at least one remained portion under the recess
Implementation Method 2
etching the first patterned upper hard mask layer to form a second patterned upper hard mask layer having a plurality of apertures exposing a portion of the middle hard mask layer
Implementation Method 3
etching the middle hard mask layer, the lower hard mask layer, and the target layer by using the second patterned upper hard mask layer as a mask to form a patterned target layer
Data Source
AI summary
A method for manufacturing a semiconductor structure includes forming a target layer, a lower hard mask layer, a middle hard mask layer, and an upper hard mask layer in sequence on a substrate. A first mask layer is then formed on the upper hard mask layer. A first patterned upper hard mask layer having at least one recess and at least one remained portion under the recess is formed, wherein the remained portion remains a thickness that is less than a depth of the recess. A patterned organic layer is then formed on the recess. A second patterned upper hard mask layer is form by etching the first patterned upper hard mask layer. A patterned target layer is then formed by etching the middle hard mask layer, the lower hard mask layer, and the target layer by using the second patterned upper hard mask layer as a mask.