Semiconductor Archives - EFFECT Photonics

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January 10, 2024

From the Lab Boutique to High Volume Production: How to Scale Up Photonics Manufacturing

Photonics, the science and technology of generating, detecting, and manipulating light, has witnessed remarkable progress…

Photonics, the science and technology of generating, detecting, and manipulating light, has witnessed remarkable progress in recent years. From cutting-edge research in academic labs to breakthrough innovations in startups, photonics is poised to revolutionize various industries, from telecommunications to healthcare. However, despite its tremendous potential, the transition from boutique lab-scale production to high-volume manufacturing remains a significant challenge.

To overcome this hurdle, the photonics industry must draw lessons from the successful scaling of electronics manufacturing. By adopting key strategies and practices that have propelled the electronics industry into the realm of mass production, photonics can pave the way for widespread adoption and integration into our everyday lives.

Learning from Electronics Packaging

A key way to improve photonics manufacturing is to learn from electronics packaging, assembly, and testing methods that are already well-known and standardized. After all, building a new special production line is much more expensive than modifying an existing production flow.

One electronic technique essential to transfer into photonics is ball-grid array (BGA) packaging. BGA-style packaging has grown popular among electronics manufacturers over the last few decades. It places the chip connections under the chip package, allowing more efficient use of space in circuit boards, a smaller package size, and better soldering.

Figure 1: Top, bottom, and side views of a ball-grid array (BGA) style package.

Another critical technique to move into photonics is flip-chip bonding. This process is where solder bumps are deposited on the chip in the final fabrication step. The chip is flipped over and aligned with a circuit board for easier soldering.

Figure 2: Simplified steps of the flip chip bonding process.

These might be novel technologies for photonics developers who have started implementing them in the last five or ten years. However, the electronics industry embraced these technologies 20 or 30 years ago. Making these techniques more widespread will make a massive difference in photonics’ ability to scale up and become as available as electronics.

Adopting BGA-style packaging and flip-chip bonding techniques will make it easier for PICs to survive this soldering process. There is ongoing research and development worldwide, including at EFFECT Photonics, to transfer more electronics packaging methods into photonics. PICs that can handle being soldered to circuit boards allow the industry to build optical subassemblies that are more accessible to the open market and can go into trains, cars, or airplanes.

Supply Chain Optimization

Electronics manufacturers have honed the art of supply chain management to achieve cost-effective and efficient production processes. This includes strategies like just-in-time inventory management, lean manufacturing principles, and global sourcing. In contrast, the photonics industry often faces challenges related to specialized materials and components, resulting in longer lead times and higher costs.

Photonics manufacturers can learn from electronics by implementing supply chain optimization strategies. This involves diversifying sources, streamlining production workflows, and leveraging economies of scale. By fostering strategic partnerships with suppliers and embracing advanced inventory management systems, the photonics industry can overcome the hurdles that have hindered its growth.

Figure 3: Key locations of EFFECT Photonics’ global supply chain. This includes our offices but also some locations where manufacturing is outsourced. We don’t mention the locations of our off-the-shelf component suppliers.

The Advantages of Moving to a Fabless Model

Increasing the volume of photonics manufacturing is a big challenge. Some photonic chip developers manufacture their chips in-house within their fabrication facilities. This approach has some substantial advantages, giving component manufacturers complete control over their production process.

Figure 4: Simplified value chain diagram of a vertically-integrated optical transceiver developer. The developer handles the PIC design, manufacturing, and packaging.

However, if a vertically-integrated chip developer wants to scale up in volume, they must make a hefty capital expenditure (CAPEX) in more equipment and personnel. They must develop new fabrication processes as well as develop and train personnel. Fabs are not only expensive to build but to operate. Unless they can be kept at nearly full utilization, operating expenses (OPEX) also drain the facility owners’ finances.

Especially in the case of an optical transceiver market that is not as big as that of consumer electronics, it’s hard not to wonder whether that initial investment is cost-effective. For example, LightCounting estimates that 55 million optical transceivers were sold in 2021, while the International Data Corporation estimates that 1.4 billion smartphones were sold in 2021. The latter figure is 25 times larger than that of the transceiver market.

Electronics manufacturing experienced a similar problem during their 70s and 80s boom, with smaller chip start-ups facing almost insurmountable barriers to market entry because of the massive CAPEX required. Furthermore, the large-scale electronics manufacturing foundries had excess production capacity that drained their OPEX. The large-scale foundries ended up selling that excess capacity to the smaller chip developers, who became fabless. In this scenario, everyone ended up winning. The foundries serviced multiple companies and could run their facilities at total capacity, while the fabless companies could outsource manufacturing and reduce their expenditures.

This fabless model, with companies designing and selling the chips but outsourcing the manufacturing, could also be the way to go for photonics. The troubles of scaling up for photonics developers are outsourced and (from the perspective of the fabless company) become as simple as putting a purchase order in place. Furthermore, the fabless model allows photonics developers to concentrate their R&D resources on the end market. This might be the most straightforward way for photonics to move into million-scale volumes.

Takeaways

Scaling up photonics manufacturing from boutique labs to high-volume production is a pivotal step in realizing the full potential of this transformative technology. By taking a page from the electronics industry’s playbook, focusing on standardization, optimizing the supply chain, and embracing automation, the photonics industry can overcome the challenges that have impeded its growth. With concerted efforts and strategic investments, the future of photonics looks poised for a paradigm shift, bringing us closer to a world illuminated by the power of light.

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Tags: automation, BGA packaging, EFFECT Photonics, electronics, Fabless model, Flip-chip bonding, Global sourcing, innovation, Integrated circuits, Integrated Photonics, Just-in-time inventory, Lean manufacturing, Manufacturing, Optical transceiver, Photonics, PICs (Photonic Integrated Circuits), R&D, Scaling up, Semiconductor, Standardization, supply chain

The Fabrication Process Inside a Photonic Foundry

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May 24, 2023

The Fabrication Process Inside a Photonic Foundry

Photonics is one of the enabling technologies of the future. Light is the fastest information…

Photonics is one of the enabling technologies of the future. Light is the fastest information carrier in the universe and can transmit this information while dissipating less heat and energy than electrical signals. Thus, photonics can dramatically increase the speed, reach, and flexibility of communication networks and cope with the ever-growing demand for more data. And it will do so at a lower energy cost, decreasing the Internet’s carbon footprint. Meanwhile, fast and efficient photonic signals have massive potential for sensing and imaging applications in medical devices, automotive LIDAR, agricultural and food diagnostics, and more.

Given its importance, we should discuss the fabrication processes inside photonic semiconductor foundries.

Manufacturing semiconductor chips for photonics and electronics is one of the most complex procedures in the world. For example, back in his university days, EFFECT Photonics co-founder Boudewijn Docter described a fabrication process with 243 steps!

Yuqing Jiao, Associate Professor at the Eindhoven University of Technology (TU/e), explains the fabrication process in a few basic, simplified steps:

Grow or deposit your chip material
Print a pattern on the material
Etch the printed pattern into your material
Do some cleaning and extra surface preparation
Go back to step 1 and repeat as needed

Real life is, of course, a lot more complicated and will require cycling through these steps tens of times, leading to processes with more than 200 total steps. Let’s go through these basic steps in a bit more detail.

Figure 1: Basic steps of a semiconductor fabrication process that are repeated in a single fabrication cycle. An entire wafer manufacturing process requires tens of these cycles.

1. Layer Epitaxy and Deposition: Different chip elements require different semiconductor material layers. These layers can be grown on the semiconductor wafer via a process called epitaxy or deposited via other methods, such as physical or chemical vapor deposition.

Figure 2: Simplified example of PIC elements and their required material layers. Source: Smit et al. (2014)

2. Lithography (i.e., printing): There are a few lithography methods, but the one used for high-volume chip fabrication is projection optical lithography. The semiconductor wafer is coated with aphotosensitive polymer film called a photoresist. Meanwhile, the design layout pattern is transferred to an opaque material called a mask. The optical lithography system projects the mask pattern onto the photoresist. The exposed photoresist is then developed (like photographic film) to complete the pattern printing.

Figure 3: Comparison of different optical lithography approaches. Contact and proximity printing keeps the mask in contact with or close to the sample. Projection printing keeps the mask further away and is initially more expensive, but it is the technology of choice for high-volume manufacturing. Source: J. Shen, University of Waterloo Ph.D. Thesis (2018)

3. Etching: Having “printed” the pattern on the photoresist, it is time to remove (or etch) parts of the semiconductor material to transfer the pattern from the resist into the wafer. Etching techniques can be broadly classified into two categories.

Dry Etching: These processes remove material by bombarding it with ions. Typically, these ions come from a plasma of reactive gases like oxygen, boron, chlorine, etc. This approach is often used to etch a material anisotropically (i.e., in a specific direction).
Wet Etching: These processes involve the removal of material using a liquid reactant. The material to be etched is immersed in the solution, which will dissolve the targeted material layers. This solution usually consists of an acid, such as hydrofluoric acid (HFl), to etch silicon. Wet etching is typically used for etching a material isotropically (i.e., in all directions).

Figure 4: Example of what a semiconductor wafer with resist (red color) on top of it looks like before and after an etching step.

4. Cleaning and Surface Preparation: After etching, a series of steps will clean and prepare the surface before the next cycle.

Passivation: Adding layers of dielectric material (such as silica) to “passivate” the chip and make it more tolerant to environmental effects.
Planarization: Making the surface flat in preparation for future lithography and etching steps.
Metallization: Depositing metal components and films on the wafer. This might be done for future lithography and etching steps or, in the end, to add electrical contacts to the chip.

Figure 5 summarizes how an InP photonic device looks after the steps of layer epitaxy, etching, dielectric deposition and planarization, and metallization.

Figure 5: Cross-section of a semiconductor wafer structure after (a) epitaxial growth, (b) etching, (c) passivation and planarization, (d) metallization.

After this fabrication process ends, the processed wafers are shipped worldwide to be tested and packaged into photonic devices. This is an expensive process we discussed in one of our previous articles.

Takeaways

The process of making photonic integrated circuits is incredibly long and complex, and the steps we described in this article are a mere simplification of the entire process. It requires tremendous knowledge in chip design, fabrication, and testing from experts in different fields worldwide. EFFECT Photonics was founded by people who fabricated these chips themselves, understood the process intimately and developed the connections and network to develop cutting-edge PICs at scale.

Tags: Agricultural, Carbon Footprint, Chip Material, Cleaning, Communication Networks, Deposition, Energy Cost, Epitaxy, Etching, Fabrication Process, Food Diagnostics, Integrated Photonics, LIDAR, Lithography, Manufacturing, Medical Devices, Metallization, Photonic Foundry, Photonics, Semiconductor, Sensing and Imaging, Surface Preparation

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Telecom/Datacom

Emerging Industries

DSP & FEC

Ultra Pure Light Sources

Ecosystems

Pluggable Modules – Direct Detect

Pluggable Modules – Coherent

Sub-Assemblies

ASICs

View All

Insights

Press Releases

In the News

Events

Careers

Knowledge Center

Company Info

Contact Us