The Littelfuse Silicon Valley Technology Center takes research and development to the next level

-March 16, 2017

On October 10, 2016 the Littelfuse Silicon Valley Technology Center had its grand opening in Fremont, CA. This new facility combines Littelfuse Materials Development and Advanced Development teams into one facility and was designed to enable collaboration and creativity as well as to incorporate the latest tools and equipment to facilitate development of next-generation products for the industry’s electronics and automotive sectors.

I had the pleasure of visiting with Clifton Tsang, Ph.D, Senior Materials Engineer at this new Technology Center in February and I saw how Littelfuse research and development capabilities will be taken to the next level.



EDN editor Steve T (left) toured the Littelfuse Technology Center with Dr. Clifton Tsang (right).

Materials and processing capabilities

Our first stop was to see how a protective device is born for one or more customers’ special application. As an example case, Dr. Tsang chose a Polymeric Positive Temperature Coefficient (PPTC) device which offers a resettable overcurrent/over-temperature protection alternative to a non-resettable solution.

Littelfuse Polymeric PTCs (PPTCs) are made chiefly of polymer mixed with conductive particles. During an overcurrent event, a PPTC will heat and expand, which in turn causes the conducting particles to break contact and stop the current. The general procedure for resetting the device after an overload has occurred is to remove power and allow the device to cool down. This device can reduce warranty, service and repair costs.

    

Here we see the flow of materials, manufacturing, and test at each step in the creation of a special product such as a PPTC (Image courtesy of Littelfuse).

 

Lab scale mixing/compounding/blending

 

 

This step is the screening process using a mixer. This mixer simulates what the production process would be, but on a laboratory scale for small batch screening. The data acquisition system (DAS) controls melt, torque, and temperature and intensely mixes the chosen raw material like conductive particles, which are an electrically conductive compound.


Plasma chamber


 

The plasma chamber performs surface treatment and etching of the material via electrodes in an Oxygen, Nitrogen, Argon, CF4 atmosphere, or any combination of these gases.


When a gas is placed under a low pressure and then subjected to a high frequency oscillating electromagnetic field, the accelerated ions in the gas will collide with the gas molecules ionizing them and forming plasma. These ionized gas particles contained in the plasma will interact with a solid surface that is placed in such an environment, and thus can remove organic contamination from surfaces. Subsequently the high-energy plasma particles will combine with the surface contaminant and will form carbon dioxide (CO2) or methane (CH4).

The working principle of a plasma chamber


The chamber is also capable of modifying or enhancing the physical and chemical characteristics of surfaces. A chemical reaction will occur between the plasma gas molecules and the surface undergoing treatment.

A sample is placed in the reaction chamber. Low flow rates of process gas at low pressure are then subjected to electromagnetic radiation thus creating plasma, at near ambient temperatures, within the chamber.


 

Here is an example of modifying the surface of a polydimethylsiloxane (PDMS) material in the plasma chamber.

 


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