Achieve Better, Lower-Cost Handling of Chamber Exhaust
New Applied Materials Aeris™ Systems Prevent Material Deposits, Treat Hazardous Chemicals
By Jim L'Heureux, Dustin Ho, Andreas Neuber
Managing chamber effluent has never been more important, given the need to maintain high tool productivity while meeting cost, environmental and safety requirements.
Yet the growing presence of hard-to-treat, potentially hazardous and flammable substances in the effluent is making it more difficult and costly.
These challenges result from the diverse processes, chemistries and materials used in semiconductor manufacturing today. Inadequate treatment can lead to clogged forelines and premature pump failures in the subfab, along with the need for increased preventive and unscheduled tool maintenance,potential exposure of personnel to hazardous materials, or even the risk of fire (figure 1).
Figure 1. Semiconductor processing may result in chamber effluent containing highly reactive chemicals and high levels of particulates. If inadequately managed, these can lead to increased tool downtime, more frequent or unscheduled predictive maintenance, and safety/environmental concerns.
To help manufacturers deal with these increasingly difficult exhaust management challenges, Applied Materials is introducing the Aeris-S and Aeris-Si pre-pump plasma abatement systems.
Intended for use with 200mm and 300mm CVD, ALD and selective removal chambers, these new Aeris systems are designed to cost-effectively manage potentially dangerous chemistries in chamber effluent; reduce the accumulation of conducting or insulating deposits in subfab forelines, valves and pumps; and reduce the possibility of personnel exposure to hazardous substances.
Extensive testing in a variety of manufacturing environments at customer fabs has shown that using an Applied Aeris-S or -Si plasma abatement system can deliver an ROI within one year or less in especially severe environments.
A DIFFERENT WAY TO TREAT CHAMBER EXHAUST
In general, traditional abatement solutions simply attempt to dilute the exhaust gas stream or improve the movement of solids through the exhaust system with brute force, using oversized or redundant pumps and other methods (figure 2). But the performance of these systems is inadequate for many applications. In addition they cannot effectively manage reactive chemistries and are energy-inefficient.
Figure 2. The figure shows commonly used abatement solutions for chamber effluent. They are not optimized for the increasingly difficult exhaust-management challenges of today’s fabs.
In contrast to conventional systems, Applied’s pre-pump Aeris-S and -Si plasma systems actually prevent the accumulation of solids in the foreline and pump from the outset. At the same time, they reduce the amount of potentially dangerous chemicals flowing through the exhaust system. The Aeris systems do this by using plasma and compounds in the effluent itself to convert precipitated solids and by disassociating complex molecules, instead of simply trying to improve the movement of solids and chemicals to end-of-line abatement.
Also, having the Aeris units located upstream of the pump enables them to work with the actual process gas stream. This is a much smaller, more concentrated gas volume that can be treated more effectively than large amounts of post-pump waste gas.
Applied Aeris units have significant capacity and process window advantages, with high total flow rates of 5–100 slm (standard liters per minute) and vacuum pressures of 100 mTorr–5 Torr. They can handle dielectrics, metals and corrosives in chamber effluent with high reliability, have a small physical footprint (or no added footprint at all, in some configurations), and are adaptable for evolving applications.
AERIS-S TREATS “DIRTY” GASES
Applied’s Aeris-S plasma abatement system (figure 3) is an all-purpose solution that can effectively handle high flow rates of even the dirtiest streams of chamber effluent, i.e., those most likely to lead to accumulations of solids, including potentially hazardous materials. It is designed for use with waste gas that may contain:
Figure 3. Two views of the new Applied Materials Aeris-S pre-pump plasma abatement system. It helps semiconductor manufacturers reduce subfab maintenance costs and related tool downtime, while improving subfab and worker safety.
- Unstable molecules such as fluorine, chlorides, metalorganic precursors, etc.
- Results of incomplete reactions in the process chamber such as HCDS, TEMAZ, etc.
- High concentrations of solids such as nitride, TEOS, etc.
For one customer’s HARP XT process, the new Applied Aeris-S system increased pump life from 2 to 12 months, resulting in a 2% improvement in tool uptime. ROI for that specific application is estimated at one year, which does not include wafer scrap and rework costs that otherwise would be incurred because of more frequent unscheduled downs.
AERIS-Si PREVENTS LARGE SIO2 DEPOSITS
The new Applied Aeris-Si plasma abatement system is especially suited for high-flow TEOS processes and other applications that lead to very heavy accumulations of SiO2 in pumps and forelines.
Figure 4. The new Applied Materials Aeris-Si assembly features mechanisms to mitigate heavy accumulations of SiO2 in pumps and forelines.
It adds and integrates a proprietary assembly (figure 4) that contains a particle trap plate and cooling plate to capture and then convert particles into easier-to handle species prior to the pump inlet (figure 5). Operation is triggered by chamber NF3 cleans.
As a result, SiO2 deposition at the pump inlet—a significant existing failure mode—is reduced. For example, used in a TEOS application at one customer facility Applied’s Aeris-Si plasma abatement system led to an improvement in pump life of at least eight months, an estimated tool uptime improvement of >7%, and an ROI of six months or less.
Figure 5. (a) A representation of the new Applied Aeris-Si assembly. (b) During TEOS processing, SiO2 particles in chamber effluent are captured in the Aeris-Si assembly instead of being deposited on the pump. (c) Once the wafer-processing step is complete, the plate is cleaned by introducing NF3 into the assembly as a source of highly reactive fluorine (F) radicals. Activated by the system’s remote plasma source (RPS), they convert the SiO2 into SiF4, thereby removing the SiO2 buildup. A fab’s central scrubber can easily handle SiF4.
EXPANDED ABATEMENT PORTFOLIO
The new Applied Materials Aeris-S and -Si systems add to the company’s existing portfolio of industry-leading subfab solutions. These include the Applied Materials iSystem™ controller and the Aeris™-G pre-pump plasma abatement system.
The Applied iSystem controller is a central monitoring and reporting platform used to optimize and automate subfab resource and safety management. The Aeris-G abatement system is designed to help customers meet increasingly strict emissions regulations and reduce their carbon footprints, while maximizing system uptime and reducing overall costs.
With Applied subfab solutions, customers can achieve meaningfully higher levels of productivity, safety, environmental performance and cost-efficiency in their manufacturing operations.
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