Semiconductor Plug Structure for Ultra-Thick Capacitor Stress Management
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Solution Overview
Problem
Existing plug structures for semiconductor devices are inadequate for ultra-thick capacitors due to limited gap filling capabilities, leading to non-uniform stress and wafer warpage issues, especially in high-voltage applications where thicker interlayer dielectric layers are required.
Innovation Solution
A semiconductor structure with alternately stacked compressive and tensile stress dielectric layers, combined with a conformally formed conductive plug and insulating plug, which reduces the number of process steps and ensures uniform stress, addressing the gap filling limitations and wafer warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thicker interlayer dielectric layers are used in high-voltage devices, then breakdown prevention within metal layers is improved, but gap filling capability deteriorates and wafer warpage increases
Solution Approach 1:
The interlayer dielectric layer is segmented into multiple thin layers (first dielectric layer, second dielectric layer, third dielectric layer) instead of using a single thick layer. This segmentation enables complete gap filling in each thin layer while achieving the required total thickness for breakdown prevention, and allows stress compensation between layers to prevent wafer warpage.
2Reliability
If thicker interlayer dielectric layers are used in high-voltage devices, then breakdown prevention within metal layers is improved, but stress uniformity deteriorates causing wafer warpage
Solution Approach 1:
The stress parameters of different dielectric layers are changed and optimized. The first dielectric layer has compressive stress, the second dielectric layer has tensile stress, and the third dielectric layer has compressive stress. By adjusting the stress parameters (magnitude and direction) of each layer, the patent achieves stress compensation and uniformity, preventing wafer warpage while maintaining the required total thickness for breakdown prevention.
3Ease of manufacture
If conventional plug structures are used, then manufacturing process is simple, but they are inadequate for ultra-thick capacitors due to limited gap filling capabilities
Solution Approach 1:
The plug structure is segmented into multiple components formed in sequence: first conductive plug, first insulating plug, second conductive plug, and second insulating plug. This segmentation allows each component to be formed with optimal process parameters, ensuring complete gap filling in ultra-thick capacitors while maintaining a manageable manufacturing process through modular fabrication steps.
Data Source
AI summary
A semiconductor structure includes a conductive feature on a substrate. A plurality of first dielectric layers are disposed on the conductive feature, and stress directions of at least two of the first dielectric layers are different from one another. A first hole penetrates through the plurality of the first dielectric layers to expose the conductive feature. A first conductive plug conformally covers the first hole and is electrically connected to the conductive feature. A first insulating plug on the first conductive plug fills the first hole.