Method for obtaining and controlling elevated temperature within a device contactor to prevent heatsinking at device test.
Original Publication Date: 2002-Oct-18
Included in the Prior Art Database: 2003-Jun-21
A process to be used to control the device temperature during elevated electrical test is discussed. The primary objective of this process is to eliminate the heat sink path that normally exists from the device, through the contact elements of the test contactor and into the Device Interface Board (DIB) and electrical Test system With the current design of most automated module handler systems (see figure), the modules 12 to be tested at elevated temperatures (temperatures above room temperature) are held in a heat chamber 11 prior to being placed in the test contactor 13 for electrical testing. The handler heat chamber 11 is set to the required test temperature and it is assumed that once the device inside the module package 12 is at the required temperature that it will remain at that temperature during test. Of all the automated handler systems evaluated, none of them are able to maintain the device at the correct test temperature during electrical test. When the handler inserts the module12 into the test contactor 13, there is an immediate heat transfer from the device 12 through the contactor contact elements 14, through the DIB 15, through the Dib/Test System contact elements 16 and into the Test system 17. This problem is due to the fact that the electrical path for each device pad is also a heat path. Even on handler systems that have direct air forced at the module side of the contactor 13, the other end of the test contactor (DIB Test System) will be at some temperature value between the handler chamber and room temperature. The solution to eliminating heat transfer from the device into the contactor, DIB and Test system is to eliminate the temperature difference. A modification to the test contactor was used to obtain these results. A hole is drilled into the side of the test contactor 13 which extends into the chamber that holds the contactor contact elements 14. Then an air fitting 18 is installed into the hole which will allow heated air to be forced into the contactor cavity. The temperature that is forced into the chamber must be of sufficient force or temperature to eliminate the thermal path. In our studies it was found that with our product being tested at 87 degrees C, we would drop internal temperatures of the device between 15 and 20 degrees C when the module 12 was placed into the test contactor 13 by the handler. With the modified contactor we were able to force a higher temperature air into the contactor and totally eliminate the device internal temperature drop when inserted into the test contactor.