MB91645A Series
46
DS07-16911-1E
2.
Precautions for Package Mounting
Package mounting may be either lead insertion type or surface mount type. In either case, for heat resistance
during soldering, you should only mount under FUJITSU MICROELECTRONICS's recommended conditions.
For detailed information about mount conditions, contact your sales representative.
Lead Insertion Type
Mounting of lead insertion type packages onto printed circuit boards may be done by two methods: direct
soldering on the board, or mounting by using a socket.
Direct mounting onto boards normally involves processes for inserting leads into through-holes on the board
and using the flow soldering (wave soldering) method of applying liquid solder.
In this case, the soldering process usually causes leads to be subjected to thermal stress in excess of the
absolute ratings for storage temperature. Mounting processes should conform to recommended mounting con-
ditions.
If socket mounting is used, differences in surface treatment of the socket contacts and IC lead surfaces can lead
to contact deterioration after long periods. For this reason it is recommended that the surface treatment of socket
contacts and IC leads be verified before mounting.
Surface Mount Type
Surface mount packaging has longer and thinner leads than lead-insertion packaging, and therefore leads are
more easily deformed or bent. The use of packages with higher pin counts and narrower pin pitch results in
increased susceptibility to open connections caused by deformed pins, or shorting due to solder bridges.
You must use appropriate mounting techniques. FUJITSU MICROELECTRONICS recommends the solder reflow
method, and has established a ranking of mounting conditions for each product. Users are advised to mount
packages in accordance with FUJITSU MICROELECTRONICS ranking of recommended conditions.
Lead-Free Packaging
Note: When ball grid array (BGA) packages with Sn-Ag-Cu balls are mounted using Sn-Pb eutectic soldering,
junction strength may be reduced under some conditions of use.
Storage of Semiconductor Devices
Because plastic chip packages are formed from plastic resins, exposure to natural environmental conditions will
cause absorption of moisture. During mounting, the application of heat to a package that has absorbed moisture
can cause surfaces to peel, reducing moisture resistance and causing packages to crack. To prevent, do the
following:
(a) Avoid exposure to rapid temperature changes, which cause moisture to condense inside the product. Store
products in locations where temperature changes are slight.
(b) Use dry boxes for product storage. Products should be stored below 70% relative humidity, and at temper-
atures between 5
°C and 30 °C. When you open Dry Package that recommends humidity 40% to 70%
relative humidity.
(c) When necessary, FUJITSU MICROELECTRONICS packages semiconductor devices in highly moisture-
resistant aluminum laminate bags, with a silica gel desiccant. Devices should be sealed in their aluminum
laminate bags for storage.
(d) Avoid storing packages where they are exposed to corrosive gases or high levels of dust.