Self-Aligned Contact Vias in Semiconductor Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of top contacts in optoelectronic devices is challenging due to their exposure to light, which complicates the fabrication process and increases costs, especially in terms of photomask usage and layout density.
Innovation Solution
The implementation of self-aligned contact vias formed within enclosures defined by sidewall spacers of neighboring active devices, reducing the need for photomasks and enhancing layout density and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional photolithography methods are used to form top contact vias in optoelectronic devices, then electrical connections can be established, but the exposed top surface requires additional photomasks and reduces layout density
Solution Approach 1:
The sidewall spacers automatically define the contact via locations through their geometric arrangement around active devices, eliminating the need for external photomask guidance. The structure serves its own alignment function, reducing manufacturing complexity.
Solution Approach 2:
Sidewall spacers are formed in advance around active devices before contact via formation. This preliminary structuring pre-establishes the alignment references needed for subsequent via formation, simplifying the overall process.
2Ease of manufacture
If traditional photolithography methods are used to form top contact vias, then electrical connections can be established, but layout density is reduced due to additional photomask steps
Solution Approach 1:
The method uses the device's own sidewall structures to define contact locations, eliminating the need for additional photomask layers. This self-alignment approach increases layout density by removing redundant patterning steps.
3Adaptability or versatility
If the top surface is exposed for light propagation, then optoelectronic function is enabled, but contact via formation becomes more difficult
Solution Approach 1:
The contact via formation is shifted from the problematic top surface plane to the vertical sidewall dimension. By forming vias along the sidewalls defined by spacers, the method avoids the exposure issues of the top surface while maintaining electrical connectivity.
Data Source
AI summary
A semiconductor device includes a substrate, a group of devices, a plurality of sidewall spacers and a contact structure. The group of the devices is arranged over the substrate. The plurality of sidewall spacers are over lateral surfaces of the group of the devices. The sidewall spacers abut one another and cooperatively define an enclosure between the devices. The contact structure is arranged between the devices in the enclosure. The contact structure is electrically connected to one device of the group of the devices.