Reevaluating the Toxicity of Semiconductor Manufacturing

April 13, 2021 by Tyler Charboneau

The safety of semiconductor manufacturing employees is a top priority. Still, these facilities handle toxic materials that can pose a hazard to human health.

When it comes to producing critical electronics, it's crucial to consider costs beyond monetary investment. Worker safety is essential in manufacturing. Unfortunately, many microelectronics manufacturing processes involve toxic chemical elements that can pose health hazards.


Semiconductor manufacturing processes with corresponding toxic chemicals

Semiconductor manufacturing processes with corresponding toxic chemicals. Image used courtesy of EPA

What risks exist, and how are personnel working to mitigate them?


Understanding Potential Dangers

Semiconductor facilities utilize multiple liquids and solvents—acidic, alkaline, or otherwise—that can be as hard on human physiology as they are on the materials they treat. 

Aside from being caustic, many commonly-used chemicals are known human carcinogens. Some examples that can carry high risk are toluene, acetone, methylene chloride, xylene, chloroform, and isopropyl alcohol. Others—like glycol ethers—may even cause reproductive harm.

Often, workers can accidentally absorb these substances through direct skin contact; however, direct contact isn't the only way to be affected. Inhalation of harmful gaseous byproducts like ozone, carbon monoxide, and phosgene can also cause numerous health issues, including skin irritation, eye damage, headaches, and digestion issues, among many others. 

Fabricators establish safety procedures to minimize risks—in accordance with guidelines from OSHA, the CDC, ANSI, and SESHA. These safety standards often include personal protective equipment (PPE). 


Material Hazards

Metals are undeniably crucial in semiconductor production. Cadmium, tellurium, gallium, mercury, and arsenic are cornerstone elements within specific chips. These elements are chiefly present within chemical compounds like mercury cadmium telluride or gallium arsenide. These compounds are favorable within semiconductors thanks to their electrical properties.


Semiconductor manufacturing employees wearing personal protection equipment

Semiconductor manufacturing employees wearing personal protection equipment. Image used courtesy of the Semiconductor Industry Association

However, each poses a fundamental hazard to human health during acute or repeated exposure.

It is important to note that these metals can exist in different forms—whether they're solids, powders, or liquids. OSHA and other agencies define workplace exposure limits to these elements, while workers and floor engineers wear PPE to help restrict exposure. 


Are Silicon Chips Hazardous After Manufacturing?

Even the small, metallic particles used during semiconductor production don't just disappear. These compounds can remain in finished semiconductor products, like solar panels. There's concern that these harmful nanoparticles may be released or leach into other materials during handling—thus contacting the skin or inadvertently entering the body. 


Diagram showing the displacement of nanoparticles within the body and the possible effects.

Diagram showing the displacement of nanoparticles within the body and the possible effects. Image used courtesy of Chao Zeng

One way to help circumvent potential hazards is to move away from the toxic materials altogether. 


Exploring Safer Alternatives

Since there are so many potential risks, there's a push to move away from periodic heavy metals toward organic compounds. Engineering researchers are proposing less toxic (or non-toxic) semiconductor materials, which function similarly to the currently-used materials. However, viability will depend on the application at hand. 

One promising semiconductor compound is Ca3SiO—comprised of calcium, silicon, and oxygen. Compounds like these are considered oxysilicides, which have previously been unable to emit infrared radiation. This limitation helped bring our existing toxic semiconductors into prominence. Thankfully, new research from Japan's National Institute for Materials Science and the Tokyo Institute of Technology has led to a breakthrough in direct transition semiconductor design. 

These emerging chips may help power fiber-optic communications, night vision devices, and solar panels. The small bandgap characteristic of these chips will provide significant performance advantages moving forward. This characteristic is critical for absorbing, emitting, and detecting longer IR wavelengths. Another benefit is in thin-film applications, including those involving LEDs. 


The Ecological Benefits of Non-toxic Semiconductor Materials

These compounds are far less toxic during manufacturing and thankfully pose minimum risks during handling—as one might experience during assembly or repair. There's also an added ecological benefit. 

For every one person of the 7.8 billion people on Earth, each is producing 16 pounds of e-waste a year. Let's not forget commercial electronics and notably massive quantities of decommissioned solar panels. Instead of depositing vast amounts of heavy metals that could leach into groundwater or soils, we can discard eco-friendlier organic compounds. 


A high-level graphic showing the e-waste statistics from 2019.

E-waste statistics from 2019. Image used courtesy of Forti et al. and Global E-waste Monitor

These non-toxic alternatives won't be commercially viable for some time. Toxic compounds are still in use because of their exceptional conductive properties, which may be challenging to top without copious research.