How Innovative Changes to the SPM Process Improve Results

The SPM process is a popular wafer cleaning process that involves using a mixture of sulfuric acid and hydrogen peroxide. It quickly removes significant amounts of organic material from the surface of silicon wafers. It is ideal for stripping photoresist and hydroxylates surfaces, making them hydrophilic in preparation for the next process steps.

The SPM process uses a mixture of sulfuric acid and hydrogen peroxide and quickly removes organic material from silicon wafers. However, it is also highly corrosive and unstable. The hydrogen peroxide decays to form water, which reduces the concentration of the mixture and slows down the cleaning process.

In order to keep the process going additional hydrogen peroxide is spiked into the mixture gradually, which brings the concentration back up. As a result, the cleaning process takes place more quickly at higher temperatures, but the hydrogen peroxide decays quickly as well, affecting control accuracy. Spiking the mixture repeatedly will limit its useful life to about one day, so it needs daily replacement. Doing this, however, proves to be quite expensive, resulting in delays for the processing line.

To address this problem, Modutek has developed an innovative strategy, called “Bleed and Feed.” This helps to prolong the useful life of the SPM mixture while controlling mixture temperature and concentration precisely.

In this process, Modutek uses a two-tank system with a “clean” tank and a “dirty” tank. Small programmable amounts are regularly drained from the dirty tank and replaced with mixture from the clean tank. To restore the mixture in both tanks, sulfuric acid is added to the clean tank to replace the amount drained and small amounts of hydrogen peroxide are added to both tanks to maintain the required concentration. This semi-continuous process maintains the concentration of the mixture within narrow limits without spiking and without the increase in temperature that's caused by spiking.

With Modutek's “Bleed and Feed” method, chemical use and disposal is reduced substantially. The wafer cleaning process becomes precise and predictable, encouraging better repeatability and consistent cleaning times that result in better performance. The useful life of the mixture is also extended from one day to a week, so the frequency and cost of replacing it are significantly reduced. The equipment stays running for a longer time since it doesn't have to be shut down as often for changing mixture. Thus, downtime is lower and throughput increases.

Modutek, a leading semiconductor equipment manufacturer, works closely with their customers to develop ways to improve manufacturing process results. Learn more about them by reading the complete article, How Innovative Changes to the SPM Process Improves Results. If you have questions, or would like to discuss your specific need, contact Modutek by email Modutek@modutek.com or call 866-803-1533.

Systems That Support Chemical Delivery and Disposal Requirements

Chemicals that are used by manufacturers and research centers have to stored safely, delivered in precise quantities, and neutralized safely prior to disposal. Chemical delivery systems manage the distribution, use and disposal of chemicals. They have to be designed for reliability and for compliance with local environmental regulations. Whether the chemicals they deal with are hazardous or not, these systems can reduce waste and improve productivity.

Effective chemical delivery systems make sure that the chemicals are tracked from reception through storage to use in the manufacturing process. Low storage volume alarms allow operators place orders to replenish existing supplies to ensure continuous operation. Bulk storage can take place in a separate storage area while smaller quantities can be stored close to the process. Sometimes, chemicals have to be mixed or different chemicals added to the process at different times. Both storage and delivery to the process can be automated to varying degrees. Double containment and leak detection may be required.

When these systems work properly, they ensure that all chemical waste is collected and disposed of safety in accordance with local environmental regulations.

Chemical delivery systems provide the following benefits:

• Better process flow
• Higher output quality
• Improve workplace safety
• Reduced waste

Due to these benefits, chemical delivery systems can improve manufacturing and research facility performance and reduce costs.

Modutek offers a complete line of chemical handling products that support chemical delivery and disposal. Chemical carts are units that can be easily rolled up to a process station to pump used chemicals into the Department of Transportation (DOT)-approved container within the cart. Modutek also offers chemical collection systems from five-gallon carboy DOT-approved containers to larger collection tanks and collection tank farms to support higher-volume requirements. These systems incorporate the use of software controls to monitor chemical disposal levels, leak detection and data logging to keep your facility in continuous operation.

The varied requirements for chemical handling systems that fulfill these functions mean that high customization is necessary. Modutek also designs customized systems – all their software and equipment are engineered and manufactured to meet a customer's specific requirements.

Modutek has the in-house expertise and experience to customize chemical handling systems to meet the requirements customers have. For more details read the complete article, Systems That Support Chemical Delivery and Disposal Requirements. Call Modutek at 866-803-1533 or email modutek@modutek.com if you have questions or would like to schedule a free consultation.