What Approach Most Accurately Measures and Characterizes 10-nm Or Larger Particles In Semiconductor Water?

By Murayama et al.

Iron Membranes Particles Semiconductors Troubleshooting

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“Killer” particles in ultrapure water (UPW*) are very fine particles that are a cause of low yields. “Killer” particle size is defined based on DRAM (dynamic random access memory) device half-pitch, and the trend is for it to reach 10 nanometers (nm) with the technology cycle of the scaling (1). 

There are two methods for the particle measuring in UPW, one is by a liquid particle counter (LPC), and the other one is by filtration and observation through scanning electron microscopy (SEM). In the text, the authors will refer to them as the LPC and the SEM methods. The LPC method is suitable for monitoring, because the measurement time is short and on-line installation is available. For the SEM method, it is superior for identification of the material characteristics in order to find out a cause of trouble. 

Currently, the microelectronics industry requires particle sizes of 50 nm or more and the lowest determination limit is 20 nm for both methods. Therefore, a new measurement method is necessary for the 10-nm class of the “killer” particle in the next generation of semiconductor devices.

This article presents keys of 10-nm particle measurement by the SEM method such as a newly developed filter membrane, sampling system, and the field test results. 


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