These crystals are advancing the semiconductor world
To make smarter devices, you need smaller, faster, and more powerful microchips. And to print microchips with tinier, more precise features, you need the purest optical materials — and Corning’s calcium fluoride (CaF₂) crystals are leading the way.
Corning’s calcium fluoride (CaF₂) materials enable smarter devices.
How many microchips have you used today?
Think about all the microchips you’ve relied on today: checking the weather, texting friends, starting your car, asking AI a question, badging into work, and so much more. You’ve probably used far more microchips than you can count.
Every one of those chips, regardless of what device it powers, is manufactured using light. Light enables the intricate patterns and circuits that enable a microchip to function, and the manipulation of light requires highly specialized optical materials.
Corning, with more than a century of expertise in optics and materials science, produces the purest optical components — materials that are essential to the advanced tools used in semiconductor manufacturing.
“When we deliver optical components to our chip-manufacturing customers, it’s the result of a meticulous, precise process,” says Gerald Cox, Senior Staff Scientist in Corning Advanced Optics.
How are microchips made?
To understand Corning’s role in advancing semiconductor technology, let’s explore how microchips are made.
Microchips consist of integrated electronic circuits “etched” onto thin wafers, typically made of silicon. These circuits are formed by depositing many layers of intricate patterns, stacked and aligned with extreme precision. The process used to create these patterned layers is called photolithography.
What is photolithography?
Photolithography involves exposing light-sensitive materials to precisely patterned light. This process uses a photomask, which acts like a stencil where metal lines on the photomask block light where exposure isn’t needed, allowing light to pass through and create the desired pattern on the wafer.
For today’s high-end chip manufacturing, lasers are the light sources of choice. These lasers operate at extremely short wavelengths, delivering concentrated photon energy to enable the precise etching of microscopic features. Few materials can withstand the intense energy of deep ultraviolet (DUV) lasers while maintaining high optical transmission. That’s where calcium fluoride (CaF₂) comes in.
Corning’s CaF₂ crystals are considered the gold standard for DUV applications, providing unmatched durability, optical performance, and reliability.
How are CaF₂ crystals used in photolithography?
Calcium fluoride optical components guide DUV light from the laser source to the wafer during the photolithography process. These components include windows, prisms, lenses, beam splitters, and mirrors, each playing a critical role in directing and shaping light to create the intricate patterns required for semiconductor circuits.
This graphic explains the basic photolithography process:
1. Laser light source: Generates the high-energy light that drives the patterning process.
2. Beam conditioning components: Manipulates and directs the laser beam to ensure optimal performance (e.g., uniform intensity).
3. Photomask: Acts as a stencil to create the patterned layer of the circuit design.
4. Projection lens assembly: Focuses and projects the patterned light onto the wafer surface.
5. Wafer: Receives the exposed pattern, which forms the foundation of the microchip.
Growing crystals for chip making
Corning grows its CaF2 crystals in a small town in upstate New York, where scientists and technicians oversee a manufacturing process where delicate high purity CaF2 raw materials are loaded into furnaces, and single-crystal ingots emerge after careful monitoring and precise control.
Calcium fluoride crystals must meet extremely high standards for DUV optical applications. Corning’s proprietary processes ensure that its CaF₂ materials exhibit exceptional purity, homogeneity, and laser durability. These cylindrical ingots, shown below, are sliced, polished, and finished into high-quality optical components.
“Growing crystals is both a science and an art,” James Wakeland, Laser Optics Product Line Manager, explains. “It requires years of research and expertise to ensure the material can withstand the demanding environments of DUV applications.”
A crystalline CaF₂ ingot, perfected by Corning, will be made into an optical blank and finished optical window.
Durability and performance: What sets Corning apart
DUV laser systems operate under extreme conditions, with high peak pulse energies and short pulse durations—typically lasting just nanoseconds. Optical components must endure billions of pulses over years of operation without degrading. Corning’s CaF₂ materials are engineered to meet these challenges.
“Degrading material, as you can imagine, is a big challenge in the semiconductor industry, where chipmakers want to make chips fast, without having to replace equipment frequently,” Wakeland says. “Corning has actively improved its crystalline materials for more than 25 years to meet the market demands for longer lasting and higher performing optics.”
Corning’s fabrication processes further enhance the performance and durability of its CaF₂ materials. These include surface finishing combined with adding optical and protective coatings, which extend the lifetime of laser optics by several orders of magnitude.
“Our work to decrease laser damage on these critical optical components can greatly enhance the output of our chipmaking customers,” Cox says. “And further, the better chips created, the more technical advances we can make as a society.”
Driving innovation and impact
Constant innovation in optical materials is critical to advancing semiconductor manufacturing. Corning continues to invest in research and development to improve the performance and durability of its CaF₂ products.
“Our advanced optics have a big impact around the world on the technology used in our daily lives,” Cox says. “One advancement can lead to exponential effects.”
Next time you use a smart device, think about the crystals — grown with precision and care—that helped make it possible.