Marco Succi

High Purity Hydrogen: Guidelines to Select the Most Suitable Purification Technology

Hydrogen is a gas widely used in a number of industrial applications. For example, in the electronic industry it is utilized to manufacture highly advanced devices like microprocessors, LEDs (light-emitting diodes) and solar cells. Hydrogen usage will be expanding as it is the main fuel for fuel cell technology and is used to store the excess energy generated by renewable sources such as solar and wind. In these applications the degree of purity of hydrogen is crucial and advanced purification systems are typically used to guarantee the purity. This article will review the types of purification technologies that are currently available to generate high purity hydrogen, starting from an already clean source that is at least 99.9% pure. Other technologies also widely used in gas purification, like PSA (pressure swing adsorption) and polymeric membrane separation, which are more suitable to handle a lower degree of hydrogen purity will not be discussed. This article will review the advantages and disadvantages of adsorbers, getters, cryogenic and palladium purification technologies with guidelines on how to select the most appropriate technology depending on the application and the experimental conditions.

Carbon dioxide gas purification and analytical measurement for leading edge mask and wafer cleaning

High pressure carbon dioxide provides a very effective alternative for cleaning integrated circuits and masks. This great cleaning ability is due to CO2 having the physical characteristics of both a liquid and a gas: like a gas, it diffuses rapidly, has near zero surface tension, very low viscosity and thus penetrates easily into mask features or deep wafer trenches and vias. As a liquid it can be utilized to clean particles and to solvate other chemicals such as alcohols and fluorinated hydrocarbons. This paper covers the analytical tests and characterizations carried out to assess impurity removal from 3.0 N CO2 (beverage grade) for its final utilization in mask cleaning applications.

Carbon dioxide gas purification and analytical measurement for leading edge 193nm lithography

The use of purified carbon dioxide (CO2) has become a reality for leading edge 193 nm immersion lithography scanners. Traditionally, both dry and immersion 193 nm lithographic processes have constantly purged the optics stack with ultrahigh purity compressed dry air (UHPCDA). CO2 has been utilized for a similar purpose as UHPCDA. Airborne molecular contamniation (AMC) purification technologies and analytical measurement methods have been extensively developed to support the Lithography Tool Manufacturers purity requirements. This paper covers the analytical tests and characterizations carried out to assess impurity removal from 3.0 N CO2 (beverage grade) for its final utilization in 193 nm and EUV scanners.

EUV tools: hydrogen gas purification and recovery strategies

The technological challenges that have been overcome to make extreme ultraviolet lithography (EUV) a reality have been enormous1. This vacuum driven technology poses significant purity challenges for the gases employed for purging and cleaning the scanner EUV chamber and source. Hydrogen, nitrogen, argon and ultra-high purity compressed dry air (UHPCDA) are the most common gases utilized at the scanner and source level. Purity requirements are tighter than for previous technology node tools. In addition, specifically for hydrogen, EUV tool users are facing not only gas purity challenges but also the need for safe disposal of the hydrogen at the tool outlet. Recovery, reuse or recycling strategies could mitigate the disposal process and reduce the overall tool cost of operation. This paper will review the types of purification technologies that are currently available to generate high purity hydrogen suitable for EUV applications. Advantages and disadvantages of each purification technology will be presented. Guidelines on how to select the most appropriate technology for each application and experimental conditions will be presented. A discussion of the most common approaches utilized at the facility level to operate EUV tools along with possible hydrogen recovery strategies will also be reported.

Increased yield and tool life by reduction of DUV photo contamination using parts-per-trillion pure purge gases

This paper describes some of the results collected during the study of improved purification materials, qualification of regenerability performances and newly developed ways to detect Acids, Bases and Siloxanes at the sub-ppt levels. Removal validation down to single ppt levels has been demonstrated for several impurities such as: NH3, SO2 and Hexamethyldisiloxane (HMDSO).