Elimination of liquid nitrogen (LN2) rain on test handler in semiconductor industry

• Main Author: Revee, Sharveen
• Format: Thesis
• Language: English; English
• Published: 2021
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/26865/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=121724

Liquid nitrogen is widely used in the manufacturing field as it its ability to maintain temperatures far below the freezing point of water. One of the applications of LN2 in semiconductor industry is to produce cold air to run or soak the device in cold condition also to function as the cooling agent when the handler is ramping down from running hot condition. Unlike the LN2 gas, a heater is used as the total opposite which is to heat the cold air in order to obtain the targeted temperature so that it the temperature doesn’t fall too low. However, while the heater is supplying heat, LN2 will undergo a sudden expansion when contact with the heater in the test site. The expansion of the gas creates a pressure that will block the original flow path. As the LN2 supply will be continues will ramping down, the block will cause the LN2 to forcefully leak out through Z-link joint and onto the parts of the handlers which is the belt of the input and output shuttle, the wire and cables and so on. The objectives of the experiment are to eliminate the LN2 rain without disrupting the overall performance of the machine. Moreover, to achieve a minimal CDA pressure for each zone which can guarantee LN2 mixture independent on control logic. On top of that, to provide a stable LTS CDA pressure before entering LN2 box by combining system and purge CDA supply. The pressure is targeted to be greater than 40psi while the machine is ramping from 175ºC to -55ºC. This study shows the experiment setup whereby engaging the minimum pressure of 40psi as well as the software control system that changes the duty cycle of both heater and LN2 in both zones where the LN2 rain is present and by doing that, managed to eliminate the LN2 rain issue.