Semiconductor Patterning with Sacrificial Spacers for Precision Layouts
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Solution Overview
Problem
Current semiconductor manufacturing technologies face challenges in forming patterns on wafers with high precision and complexity, particularly at smaller process nodes, leading to difficulties in matching target patterns and increasing the complexity and cost of the photolithography process.
Innovation Solution
A semiconductor structure and forming method that involves creating mandrel lines, sacrificial spacers, and filling layers to define grooves and trenches, allowing for precise control of groove positions and shapes, and using cutting layers to improve pattern precision and reduce distance between pattern elements, thereby enhancing the flexibility and freedom of layout design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional photolithography methods are used to form patterns on wafers, then the manufacturing process is simpler, but the pattern precision and ability to match target patterns deteriorates at smaller process nodes
Solution Approach 1:
The patterning process is divided into multiple stages: first forming mandrel lines, then using them as templates to create sacrificial spacers, followed by forming trenches and filling layers. This segmentation allows each step to be optimized independently, achieving high pattern precision while managing overall process complexity through systematic breakdown of the manufacturing sequence
Solution Approach 2:
Mandrel lines are formed in advance as sacrificial structures that define the positions of subsequent grooves and trenches. These preliminary structures serve as templates that guide the formation of the final pattern, ensuring high precision in matching target patterns before the actual functional layers are created
2Length of moving object
If the geometric dimension is decreased to increase functional density, then the circuit size is reduced, but the difficulty and complexity in manufacturing increases
Solution Approach 1:
Sacrificial spacers and filling layers are introduced as intermediary structures that facilitate the formation of small-geometry features. These intermediaries allow precise control of groove positions and shapes during the manufacturing process, making it easier to manufacture sub-10nm structures by providing physical templates and support structures that guide material deposition and removal
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional structured formation by creating trenches with controlled depths and shapes, and by forming filling layers that extend vertically. This dimensional transition enables precise control of lateral dimensions through vertical structure geometry, allowing smaller feature sizes to be achieved with maintained manufacturing ease
3Manufacturing precision
If more process steps are added to improve pattern precision, then the pattern transfer accuracy improves, but the process cost increases
Solution Approach 1:
The filling layer serves multiple functions: it provides structural support during trench formation, defines the upper boundary of trenches, and acts as a sacrificial material that can be selectively removed. This multi-functionality reduces the need for separate process steps, thereby controlling process costs while maintaining high pattern transfer accuracy through the versatile role of the filling layer
Data Source
AI summary
A semiconductor structure and a forming method thereof are provided. In one form, a forming method includes: forming separated mandrel lines, where opposite sidewalls of adjacent mandrel lines in a second direction are a first sidewall and a second sidewall; forming a sacrificial spacer on a sidewall of the mandrel line; forming a sacrificial layer on a part of the base between adjacent sacrificial spacers; forming a filling layer on the base; removing the sacrificial layer to form an opening; removing the sacrificial spacer to form a trench; forming a mask spacer on a sidewall of the trench, where the mask spacer is further filled between the sidewall of the mandrel line and the filling layer, and the mask spacer located on the sidewall of the trench forms a first groove; forming a second groove running through the filling layer between the sidewall of the trench and the mask spacer located on the second sidewall; removing the mandrel line to form a third groove, where a cutting layer is formed in at least one of the third groove, the second groove, and the first groove, and the cutting layer cuts the corresponding groove along the first direction; and patterning a target layer below the third groove, the second groove, and the first groove to form a target pattern. The embodiments in the present disclosure improve the pattern precision of the target pattern.