Gases find a range of applications in the electronics industry, taking on roles as reagents in chip manufacture that encompass deposition, etching, lithography, ion implantation and maintaining a totally clean fabrication environment. According to figures released by Techcet Group, electronic gas sales grew by a modest 3.2 percent in 2012 to $3.1 billion, relatively slower than the 15 percent increase seen in 2011 (see table, below).

Of all electronic gases sales, specialty gases took the lead, growing 5.0 percent to $2.1 billion, while bulk gas sales to electronics customers remained flat at $1.1 billion. The positive trend in electronic specialty gases is expected to continue through 2013, leading to total electronic gas sales in the region of $3.5 billion worldwide.

For bulk gases in electronics applications, Air Products and Air Liquide share the market lead with 28 percent share each. In specialty gases, Air Products has a comfortable seven-point lead over Air Liquide, though each has more than a 20 percent share. Praxair, Linde, TNSC, and Korean-headquartered OCI round out the other global market share leaders.

A notable acquisition
A key development in the electronic gases sector is the recent Air Liquide acquisition of Voltaix. Founded in 1986, Voltaix is an important US manufacturer of materials used in the production of semiconductor devices and advanced solar cells, with expertise and global stewardship in silicon, germanium, and boron chemistries. It operates manufacturing facilities in Branchburg (New Jersey), High Springs (Florida) and Portland (Pennsylvania) and in South Korea in Sejong-si. The company has 185 employees.

Air Liquide cited synergy between Voltaix’s technology and its own expertise in offering advanced precursors for semiconductor manufacturing. The gas major hopes that the deal will yield synergies in molecule discovery and scale-up.

A key development in the electronic gases sector is the recent Air Liquide acquisition of Voltaix…

Michael J. Graff, senior vice-president Americas and a member of Air Liquide’s Executive Committee commented, “Air Liquide and Voltaix share a culture of innovation. Joining the resources and expertise of our two companies will expand our product offering for semiconductor manufacturers around the world. Our continuous innovation on new molecules allows us to timely meet the growing consumer demand for increasingly powerful flat screens, tablets and smartphones.”

Specialty electronic gases expert Eugene Ngai, of Chemically Speaking LLC, points out that Voltaix is the only major producer of many of the upcoming high margin electronic specialty gases that are critical in the production of advanced memory, logic or PV devices. These include disilane, trymethylboron, germane and the liquid trisilylamine, in addition to many other products currently in development.

“Voltaix’s ability to work closely with the end-user and its time to market with a new or improved product is key to their reputation and success,” says Ngai. “I can only hope that the Air Liquide organization does not strangle the smaller company’s ability to innovate and lead the market, as Air Products did with the Solkatronic Chemicals acquisition in 1998.” (Ngai says as a former VP of Solkatronic when it was purchased by Air Products, he witnessed Solkatronic’s integration and the subsequent demise of many products). Ngai offers this example to make a point about specialty gas manufacturers: “Large corporations have a difficult time developing products for niche markets, the $50-100 K/year product gets lost in the $10-100 million/year products that are typical in billion dollar companies,” he explains.

On a related topic, China is now offering tax incentives for users in the PV and LED markets to source from local suppliers. “This will start to shift some of the market away from the multinationals,” Ngai predicts.

Cleaning up
Semiconductor manufacturers use gases to clean deposits off the process chamber walls. Until recently, this has predominantly been achieved using nitrogen trifluoride (NF3), although NF3 requires expensive plasma to break it apart for it to then be useful as a reactor cleaner.

Increasingly, companies are thought to be considering using fluorine (F2) because it delivers better cleaning performance, without contributing to global warming. But this highly-reactive gas is capable of burning even the stainless steel tubing conveying it. “To control this, some users are using F2 generators which add complexity to the operation,” says Ngai. “F2, however, provides a faster clean, which is critical to reactor uptime. 20 percent F2 mixtures in ISO modules are a good compromise. These have been routinely used by automotive gas tank suppliers to fluorinate plastic gas tanks.”

Even NF3 is considered more environmentally friendly than sulfur hexafluoride (which has 20,000 times the global warming potential of carbon dioxide) or perfluorocarbons like hexafluoroethane for chemical vapor deposition (CVD) applications. But NF3’s true environmental impact (which is undoubtedly orders of magnitude greater, molecule for molecule, than carbon dioxide) is still poorly understood. It is certain that perfluorocarbons and NF3 are emitted to the atmosphere as a result of the electronics and PV industries. Emissions can be limited with modern abatement technology. These concerns are a large factor in moves towards using fluorine gas instead, which is also less expensive.

Cooler customers
Techset Group’s data suggests that manufacturers adding new device structures at 22nm and below will provide some new growth opportunities for the specialty gases market. But many of these emerging applications will turn to liquid chemical precursors for high volume manufacturing, as manufacturers look to cooler process conditions.

According to Linde, trends towards lower temperature silicon deposition require new Si deposition materials such as hexachlorodisilane (HCDS). Some of these materials are not gases at room temperature and pressure, but are vaporized and delivered as a gas in the process.

“Low temperature Si deposition materials such as disilane, trisilylamine, and hexachlorodisilane allow other materials to be used in fabricating a device that would not be possible at higher temperatures,” says Ngai. “This is crucial for many of the advanced devices. The challenge for the user is that the more complex Si molecules have a greater tendency to form reactive siloxanes, which become a problem downstream of the reactor.”

In terms of gas volumes, other moves in the industry towards 450mm wafers will likely provide an increase in gas and chemical consumption. But one thing is certain with high-tech electronics manufacturers: the technology never stands still. Even with our continued thirst for ever more high-tech gadgets, the next few years will likely see specialty gases markets growing at modest, single digit rates.

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