High Aspect Ratio Opening Formation Without Sacrificial Fill
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Solution Overview
Problem
The existing methods for creating high aspect ratio structures in integrated circuit devices require sacrificial fillings in lower openings, increasing complexity and cost, as they need to be removed through top openings.
Innovation Solution
A method involving a substrate with a first layer and a cover layer, where a second layer is deposited on top to form a second opening that connects with the first opening without the need for a sacrificial filling, using a non-conformal deposition process and anisotropic etching to achieve high aspect ratio openings with a smooth transition section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If two openings are arranged on top of each other to increase depth while maintaining width, then high aspect ratio structure is achieved, but sacrificial filling is required in lower openings which increases complexity and cost
Solution Approach 1:
The patent removes the sacrificial filling requirement entirely by using a single continuous opening design. The cover layer is patterned to create one unified opening that extends through the dielectric layer, eliminating the need to deposit and remove sacrificial materials that would be required in multi-opening stacked designs.
Solution Approach 2:
The opening is divided into multiple sections with different widths along its depth. The opening has a wider upper section and a narrower lower section, allowing the upper portion to accommodate wider conductive structures while the lower portion achieves greater depth. This segmentation enables high aspect ratio without requiring sacrificial fillings.
2Stability of the object's composition
If sacrificial filling is used in lower openings, then structural support is provided during manufacturing, but additional manufacturing steps are required to remove the filling through top openings
Solution Approach 1:
The single opening design is self-supporting throughout the manufacturing process. The opening walls provide mutual support without requiring additional sacrificial materials. The design inherently maintains structural integrity during fabrication without needing separate support elements that would later require removal.
3Device complexity
If a single opening is used without sacrificial filling, then manufacturing complexity is reduced, but maintaining structural integrity at high aspect ratios becomes challenging
Solution Approach 1:
The opening has different geometric properties at different locations. The upper section has a larger width providing structural stability and access, while the lower section narrows to achieve high aspect ratio. This local variation in dimensions allows the structure to maintain integrity throughout its length while achieving the desired depth-to-width ratio.
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 allows for the formation of high aspect ratio openings without the need for sacrificial fillings, reducing complexity and cost, and provides a smooth transition section between the first and second openings, enhancing the structural integrity of the integrated circuit device.
Implementation Method 1
A cover layer is deposited on the first layer and coating a sidewall portion of the first opening
Implementation Method 2
using a non-conformal deposition process and anisotropic etching to achieve high aspect ratio openings with a smooth transition section
Data Source
AI summary
An integrated circuit device includes a substrate with a first layer situated on the substrate. The first layer defines a first opening with a cover layer deposited on the first layer and coating a sidewall portion of the first opening. A second layer is situated on the cover layer. The second layer defines a second opening extending through the second layer and through the cover layer to connect the first and second openings.