Surface Temperature of Ceramic Package and Seam Joining Condition

Micro-Parallel Seam Joining and Development of Joining Equipment (2nd Report)

Abstract

It is required, as an indispensable condition, to secure the specified hermeticity as well as to restrain temperature rise at the minimum and prevent deterioration of an element inside the package from thermal effect during hermetic sealing process of a ceramic package for which high reliability is demanded. For this reason, Thermal Video System, which is able to detect JR thermal image in real-time, was used in this experiment to observe progressive change in surface temperature distribution of a ceramic package during Micro Parallel Seam joining process. Also, the relationships between various seam joining conditions and surface temperatures obtained were studied, and some conditions were established to restrain package temperature rise while maintaining her meticity of 10^-8 atm cm³/s which is defined as the criteria for acceptance/reject of seam joining quality.
The results obtained are as follows.
(1) Package surface temperature distributions were first shown so that two high temperature areas (hot spots) appeared in the vicinity of left and right roller electrodes immediately upon start of current flow, and temperature continued to rise toward the center of lid thereafter as isothermal ring expanded from those hot spots which were to be the center. Such status continued for approximately 70% of total joining time and finally the center of lid reached the highest temperature.
(2) In order to restrain package temperature rise;
(a) Roller electrode with a greater taper angle should be used.
(b) As for seam joining conditions, electrode force and current should be selected as small as possible and joining speed faster within the range that specified herrneticity can be maintained.
(c) Lid with plating tends to cause temperature rise, especially when plating material, of which melting point is lower than that of lid material itself, used.
(3) Also, voltage between roller electrodes, current, resistance and contact width between the lid and roller electrode were discussed in relation to temperature rise of ceramic package.