Flip-Chip VCSEL Array Alignment on Transparent Substrate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in optical communications networks is to create a larger array of precisely aligned vertical cavity surface emitting lasers (VCSELs) with increased bandwidth capacity, while maintaining low manufacturing costs, as current methods face low yield due to defective semiconductor devices and alignment difficulties when using multiple devices with single or few VCSELs.
Innovation Solution
A flip-chip assembly is developed, comprising a transparent substrate with conductive contact pads and traces, and flip-chips mounted on it, which are precisely aligned with a multi-optical fiber ferrule device using mating features, ensuring accurate alignment of optoelectronic elements with optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a one-dimensional or two-dimensional array of VCSELs is fabricated on a single semiconductor substrate, then the spacing between adjacent VCSELs can be decreased and the number of VCSELs integrated can be increased, but the manufacturing yield becomes relatively low because the device is discarded if even one VCSEL is defective
Solution Approach 1:
The patent divides the VCSEL array into multiple independent semiconductor devices, where each device contains only a subset of the total VCSELs (e.g., one VCSEL per device). This segmentation allows individual devices to be manufactured separately with higher yield, and defective devices can be replaced without affecting the entire array.
Solution Approach 2:
The patent employs a hierarchical structure where multiple small semiconductor devices (containing individual VCSELs or small groups) are integrated onto a single semiconductor substrate. This nested arrangement allows the system to achieve high VCSEL density while maintaining the ability to replace only defective portions rather than the entire array.
2Reliability
If multiple semiconductor devices with single or few VCSELs are used to create a larger array, then manufacturing yield can be improved, but the alignment of VCSELs with their respective optical coupling elements becomes difficult
Solution Approach 1:
The patent incorporates alignment features directly into the semiconductor substrate during the fabrication process, before the actual VCSEL mounting occurs. These pre-formed alignment features guide the precise positioning of individual VCSELs or small arrays, ensuring accurate alignment with optical coupling elements without requiring complex post-fabrication adjustment.
Solution Approach 2:
The patent introduces alignment features as intermediary elements that mediate between the semiconductor devices and the optical coupling elements. These features serve as reference points that facilitate precise alignment during assembly, bridging the gap between the separately manufactured semiconductor devices and the optical components.
3Productivity
If a larger array of VCSELs is created to increase bandwidth capacity, then the bandwidth capacity of the optical communications network can be increased, but the manufacturing costs increase due to low yield
Solution Approach 1:
By segmenting the VCSEL array into multiple replaceable semiconductor devices, the patent enables cost-effective manufacturing through higher individual device yields. Defective devices can be replaced individually rather than requiring replacement of the entire expensive array, significantly reducing manufacturing and operational costs.
Solution Approach 2:
The patent enables selective replacement of only the defective semiconductor devices containing individual VCSELs or small groups, rather than discarding the entire VCSEL array. This approach recovers the value of functional devices and reduces waste, lowering overall manufacturing costs while maintaining high bandwidth capacity.
Data Source
AI summary
A plurality of flip-chips, each having a plurality of optoelectronic elements formed therein, are flip-chip mounted on a top surface of a substrate that is comprised of a material that is transparent to the operating wavelength of the light produced by optoelectronic elements of the flip-chips. The combination of flip-chips comprises an array of precisely-aligned optoelectronic elements. When the substrate comprising the array of optoelectronic elements is mounted on a PCB, electrical contact pads disposed on the bottom and/or top surface of the substrate are in contact with the respective electrical contact pads disposed on the top surface of the PCB to electrically interconnect the PCB with the flip-chips. Mating features on the substrate that have been precisely positioned by semiconductor fabrication steps are disposed for mating with respective mating features of a multi-optical fiber ferrule device that have been precisely formed in the ferrule device at precise locations.