Displaying items by tag: Watlow Plasmatech GmbH

Semiconductor fabrication creates a number of waste gases, which can be corrosive, pyrophoric and potentially explosive. Often, diluting these gases with nitrogen (N2) is an early step in the abatement process to make sure the gases stay below the lower explosive limit (LEL) or reduce corrosive effects. However, the use of nitrogen can cause condensation and deposits, as well as leak out of the system. Here, Rob Johnston, director of the end user business segment at industrial electric heater manufacturer Watlow, explains how this can be prevented.

Abating hazardous gases

One way to abate hazardous gases in process exhaust streams is to dilute them using a less harmless gas. In semiconductor fabrication, nitrogen gas is often used because it is readily available and effective at diluting more hazardous gases prior to other abatement steps.

A good example of this solution can be seen with potentially explosive gases, such as hydrogenated gases. These gases have an explosive range, a specific range of gas concentrations where explosion is likely to occur. Gas concentrations must be kept below the lower explosive limit (LEL), which is the minimum concentration of gas needed to reach this explosive range. But mixing with nitrogen lowers the ratio, making the gas too lean to pose an explosion risk.

That said, when introducing a new gas into the exhaust stream, condensation can cause issues by creating deposits in the system. This eventually creates clogging, leading to unplanned downtime. The addition of nitrogen poses a dilemma, forcing plants to choose potential line shutdown in order to ensure safety — a trade-off no one wants to make.

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An alternative solution

If adding room-temperature nitrogen into a waste stream causes condensation problems, heating the nitrogen can be a sufficient remedy. However, getting nitrogen to temperature has proven to be a tricky engineering problem.

One of the biggest issues is with nitrogen leaks. Introducing a heater into the system can potentially create another place where nitrogen can leak, meaning that not all the nitrogen gets into the waste stream for abatement. If the leak is severe enough, the hazardous gases will not be diluted enough to ensure safety. This means that a potentially explosive gas might still be well within its explosive range.

There is limited space that can be taken up within an existing an abatement system, which limits the number of components, controllers and wires that can be added to the system, especially in multi-chamber setups.

The no-leak last resort

To overcome these challenges, a compact, no-leak heater design can ensure the reliability of exhaust abatement systems in semiconductor fabrication. For instance, Watlow’s FLUENT® in-line heater is designed to allow movement of a fluid or gas over the heater surface without any loss of the fluid or gas through the outer shell.

A no-leak design not only includes a seamless stainless steel outer protection tube, but it also has the heating elements sitting outside of the fluid flow path. As a result, neither the elements nor the wiring penetrate the gas flow path, mitigating the need to weld components in place and thereby create areas where gas can escape. This design ensures that all nitrogen gas is passed along into the process, preventing any from escaping into the sub-fab.

With no leaks present, the correct mixture of gases can be assured, meaning that semiconductor manufacturers no longer need to trade-off between safety concerns and possible downtime caused by the need to flush clogged exhaust systems.

A first step in the abatement of waste gases in semiconductor fabrication should be dilution with nitrogen gas. However, engineers must consider the issues that can arise and consider opting for a solution that covers all potential issues associated with nitrogen heating. In this case, a design that is modelled around eliminating leakage can prevent clogging and downtime.

For more information about the FLUENT® heater, go to watlow.com

About Watlow:

Watlow is a global industrial technology company that uses its world-class engineering expertise, advanced thermal systems and manufacturing excellence to enrich everyday life. Many of the world’s leading companies leverage our technology in vital applications such as semiconductor processing, environmentally-friendly energy solutions and lifesaving medical and clinical equipment, to name a few. Founded in 1922, Watlow’s culture is driven by our purpose of “Enriching Lives Through Inspired Innovation,” enabling us to deliver high-impact solutions that improve our customers’ competitive advantage.

Published in Oil & Gas

~ How ULTRAMIC heaters support innovative analytical equipment designs ~

Advanced ceramic heaters offer numerous benefits in the design of analytical equipment. Many of the heaters used in industry today are metal sheathed, a long-standing technology that has been available for over 30 years. While such heaters are excellent for a wide variety of complex thermal applications, today’s newer and more advanced analytical equipment requires higher performance and precision. Here, Andy Selvy Chief System Designer at industrial technology company Watlow, explores the benefits of advanced ceramic heaters.

Analytical equipment, such as gas-chromatograph mass spectrometers (GC-MS), is used to determine the presence of trace chemicals, alcohols and hormones and separate complex mixtures in a number of research, industrial and clinical applications. For example, GC-MS detect concentrations of drugs in blood, as well as contaminants in air, water and soil, and can help to develop new pharmaceutical products.

The MS component breaks each separated compound coming from the GC into ionized fragments, which requires a high energy beam of electrons to pass through the sample molecule to produce electrically charged particles or ions.

The equipment requires the ionization of the sample and inert gas, and so a heating element that can reach a precise temperature quickly is a vital component. However, many legacy heating technologies that have exerted their performance and reliability and now must be designed to reflect the smaller, higher throughput analytical equipment that is taking over the market. This means heaters must also be smaller to enable miniaturization and optimize performance.

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Today’s heaters
Modern advanced ceramic heaters can achieve higher performance and precision criteria, while allowing for greater design flexibility and faster time to market.

To appreciate the recent innovation in heating technology, it helps to understand some of the limitations faced by more traditional metal heaters. These heaters must be inserted into another block of metal inside the equipment in order to perform their thermal job. As the heater sheath and the block are made of metal, they cannot meet the ion source and often require additional electrical isolation.

These design tradeoffs require a larger carbon footprint, as well as a more complex assembly procedure. Metal-sheathed heaters also typically require longer heat-up and cool-down times, given that there is more mass in the heater and holder. This results in slower system startup and changes between set points.

Advances in ceramic heater technology overcome many of these issues and offer greater design flexibility and performance. Advanced ceramic heaters allow equipment designers to create room for new components, reduce a machine’s overall footprint, improve accuracy and performance, all while simplifying the manufacturing and assembly process.

The benefits of advanced heaters
To allow for more innovative designs, Watlow has developed ULTRAMIC, an advanced, high-performance ceramic heater. ULTRAMIC advanced ceramic heaters are designed for optimal performance in thermal applications where rapid thermal cycling and more precise control is needed.

ULTRAMIC heaters are constructed from aluminum nitride (AIN) and incorporate a thermally matched, proprietary heating element. AlN is especially suitable for applications requiring a clean, non-contaminating heat source. Additionally, excellent geometric stability ensures consistent part-to-part thermal contact during heating cycles.

These components, used together in the right circumstances, give rise to a number of unique properties including high electrical isolation, with low-leakage current, superior chemical resistance, high thermal conductivity and temperature uniformity across the heater surface, plus high durability.

Today’s analytical equipment has surpassed the innovation of heaters designed 30 years ago. To ensure design innovation is not limited, equipment designers must consider more advanced heaters in their equipment.

Advanced ceramic heaters are smaller, respond faster and can be more resistant to environmental contamination compared to conventional heaters. In particular, Watlow’s ULTRAMIC advanced ceramic heaters can help analytical equipment manufacturers improve product performance and design, as well as accelerate their time to market.

For more information about Watlow’s products, go to www.watlow.com.

About Watlow:
Watlow is a global technology and manufacturing leader that provides world class engineering expertise and innovative thermal products and systems that enable customers to thrive.

Watlow brings its experience to numerous industries, including semiconductor processing, environmental chambers, energy processes, diesel emissions, medical and foodservice equipment.

Since 1922, Watlow has grown in product capability, market experience and global reach. The company holds more than 980 patents and employs 2,000 employees working in nine manufacturing facilities and three technology centers in the United States, Mexico, Europe and Asia. Watlow also has sales offices in 50 countries around the world. The company continues to grow, while the commitment remains the same – to provide its customers with superior products and services for their individual needs.

Published in Chemicals
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