Semiconductor Via Formation Using Dual Damascene Mask Overlap
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Solution Overview
Problem
The challenge in manufacturing semiconductor devices is to form vias that are small enough to align with transmission lines accurately, as existing methods face difficulties in achieving precise alignment and forming vias that are sufficiently small.
Innovation Solution
The solution involves using a dual damascene process where a via mask and a trench mask overlap in an intersection region, allowing for the formation of a via opening that is dimensioned by this intersection region, and filling both the trench and via opening in a single conductor deposition operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional via formation methods are used, then the manufacturing process is simple, but the via size cannot be sufficiently small and alignment precision is poor
Solution Approach 1:
The via formation process is segmented into multiple lithography and etching steps. First, a via mask is formed and a first etch creates a via opening. Then, a trench mask is formed and a second etch creates a trench. This segmentation allows independent optimization of via size and alignment precision without compromising process simplicity
Solution Approach 2:
The via opening is formed in advance before the trench formation. The via mask and first etch step prepare the via opening preliminarily, establishing a precise alignment reference before the trench mask and second etch step create the trench. This preliminary action ensures that the final conductor structure achieves both small via size and high alignment precision
2Productivity
If separate filling operations are used for trench and via, then the process is simpler to control, but productivity is reduced due to multiple deposition steps
Solution Approach 1:
The trench filling and via filling operations are merged into a single conductor deposition step. The conductor material is deposited simultaneously to fill both the trench and the via opening, eliminating the need for separate deposition processes. This merging significantly improves productivity while the underlying segmented etching process maintains controllability
Solution Approach 2:
The conductor structure formed is composite in nature, filling both the trench and via opening in a single operation. This composite filling approach allows the deposition process to handle multiple structures simultaneously, improving efficiency without requiring complex separate deposition sequences
Data Source
AI summary
Apparatus and methods are disclosed, including transistors, semiconductor devices and systems. Example semiconductor devices and methods include a first transmission line and a second transmission line located over one another. A via is shown connecting the first transmission line and a second transmission line wherein a first side of the via and a side of the second transmission line are coplanar. A via is also shown connecting the first transmission line and a second transmission line wherein the second transmission line tapers downward from a line width to a via width.