ST will begin mass production of silicon photonics devices next year

STMicro expects to develop the world's first silicon photonics device
by mid-2014.
STMicro obtained a production license for silicon photonics technology from Luxtera in March 2012 and began work on a 300mm (12-inch) CMOS wafer line
for silicon photonic devices.

Flavio Benetti, General Manager of STMicro's Hybrid Process Division, said: "We believe STMicro is the only company
that produces 12-inch devices.
"

STMicro has been working with Luxtera for a long time and has now signed a production agreement
.
STMicro has long supplied optical component manufacturers with CMOS and BiCMOS integrated chips, but will produce integrated chips and optoelectronic circuits
respectively in the future.
"We have the right to
produce our own products.
" Benetti said
.

The reason why STMicro has such interest in silicon photonics technology is the increase in data rates, and STMicro customers want more advanced solutions
for 100 Gig and 400 Gig.

"It is clear that conventional electronic circuits at 100 Gig and 400 Gig have limits
in speed, range and energy consumption.
" "So we conducted a thorough market survey and found silicon as one of
the viable solutions.
" "

STMicro is now looking at the short-range interconnect technology used in its data centers and needs to have its 300mm production line running
at full capacity.
STMicro hopes to offer a foundry service to other companies in the future, but the project will not be part of
its near-term operational strategy.
Benetti added: "Foundry services may be included in the long-term plan, but we will not be bringing the technology to market
as a wafer foundry.
"

Optoelectronic circuits will be produced using 65nm lithography, which balances production costs with the functional accuracy
of the device.
Test chips have already been produced
.
Benetti said: "This is the first time we have introduced an optical process into a CMOS production line, and we are very satisfied
with the results.
"

One of the challenges of silicon photonics technology is how to introduce and export light into and out of the circuit.

"If you have a device like a raster coupler, you understand that the shape and accuracy of the raster coupler is the basis of optocoupling technology," Benetti said, "If you use 90nm CMOS, the production cost is relatively low, but 65nm technology can find a good balance between production cost and technical performance
.
" As a solution, STMicro uses copper pillars to link photonic devices and electronic integrated circuits in
a 3D structure.

Separating electronic chips from photonic chips can not only improve performance and save costs
compared to fabricating a photoelectric monolithic circuit.
After separation, the photoelectric circuit can focus on the optoelectronic function, and the overall device can also use a few masks or add processing layers
.
Whether using CMOS or BiCMOS, we can provide more supporting chips for customers to choose
.
Moreover, some of STMicro's regular customers can now reuse their electronic integrated circuits
.
Benetti concludes by adding, "Customers can upgrade electronic circuits without even touching the photonic circuit
.
"

There are already manufacturers who skip the optical module manufacturer and buy and use this silicon device
directly.
This new technology may simplify the traditional optical industry supply chain
.

Benetti also highlighted silicon photonic circuit design tools
used in the production process.

STMicro's test chips were done using electronic design automation (EDA) tools, but the challenges were not all solved
.
One is how to realize the industrialization process
of introducing and exporting light into circuits.
Benetti said: "Coupling optoelectronics into fiber attachments still requires a high degree of improvement to achieve, so we are working fiber attachments and packaging technologies
.
With the help of optical fiber, we are in an era of high-speed and precise development, and we can do a lot more
.
"