Semiconductor Contact Structure With Cavity-Filled Dielectric Alignment Relief
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Solution Overview
Problem
The manufacturing of semiconductor structures is time-consuming and costly due to the complexity of forming contact holes, which requires high alignment accuracy and multiple processes, limiting the reduction of contact hole and metal connection line widths.
Innovation Solution
A semiconductor manufacturing method that reduces the number of processes for forming contact holes by creating a patterned dielectric layer with cavity regions, allowing for higher alignment tolerance and smaller contact hole and metal line widths, thereby decreasing the volume and increasing component density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple processes are used to form contact holes with high alignment accuracy, then the connection reliability is improved, but the manufacturing time and cost increase
Solution Approach 1:
The contact hole formation process is segmented into two distinct stages: first forming contact holes through the first dielectric layer to reach the active areas, then forming additional contact holes through the second dielectric layer and cap layer. This segmentation allows each stage to be optimized independently, reducing overall manufacturing time while maintaining connection reliability.
Solution Approach 2:
The first contact holes are formed in advance before the second dielectric layer is deposited. This preliminary action allows the first contact holes to be established with proper alignment to the active areas, and subsequent processing steps build upon this foundation without requiring re-alignment, thereby reducing manufacturing time while preserving reliability.
2Manufacturing precision
If multiple processes are used to form contact holes, then the alignment accuracy is improved, but the process complexity increases
Solution Approach 1:
The patterning process is segmented into two independent stages corresponding to the two dielectric layers. Each patterning step is performed separately with its own mask and etch process, allowing for optimized alignment procedures at each stage without compounding complexity. The first patterning aligns to active areas, while the second patterning aligns to the first contact holes, simplifying the overall alignment strategy.
Solution Approach 2:
The first contact holes and their associated metal connections are formed as a preliminary structure before depositing the second dielectric layer. This preliminary formation establishes a stable reference framework that simplifies subsequent alignment operations, as the second contact holes can be aligned to the already-formed first contact holes rather than requiring direct alignment to underlying active areas through multiple layers.
3Volume of moving object
If contact hole width is reduced to decrease semiconductor volume, then the component density is improved, but the alignment tolerance requirement increases
Solution Approach 1:
The contact hole structure is segmented into first contact holes with larger widths formed in the first dielectric layer, and second contact holes with smaller widths formed in the second dielectric layer. The larger first contact holes provide generous alignment tolerance, while the smaller second contact holes achieve the volume reduction goal. This segmentation allows each contact hole type to be optimized for its specific function without compromise.
Solution Approach 2:
The solution transitions from a single-dimensional approach (uniform contact hole size) to a multi-dimensional approach by introducing vertical layering with different contact hole sizes at different depths. The first contact holes extend through the first dielectric layer with larger dimensions, while second contact holes extend through the second dielectric layer with smaller dimensions, effectively using the vertical dimension to resolve the tension between volume and alignment tolerance.
Data Source
AI summary
A manufacturing method for a semiconductor structure is provided. First active areas, a second active area, and a third active area are formed. A first dielectric layer is formed on the active areas. A patterned region that includes a cavity region and a dielectric region is formed in the first dielectric layer, and the cavity region surrounds the dielectric region. A filling layer is formed in the cavity region. Multiple first contact holes and at least one second contact hole that penetrate the first dielectric layer are formed. Each first contact hole exposes a portion of the corresponding first active area, and the second contact hole replaces the dielectric region and exposes a portion of the second active area. Metal layers are filled in to the first contact holes and the second contact hole.