4.1 Storage Environment

1) Temperature and Humidity

Our recommended storage conditions are normal temperature and humidity (5 °C to 35 °C, 40% to 70%). However, the recommended storage conditions differ among our semiconductor devices. Please refer to the corresponding data sheet for more information.
When using a humidifier to maintain humidity as part of ESD protection, please use purified water to prevent rust on terminals. When using tap water, please remove chlorine by boiling or by other means in order to reduce any causes of rust before use.
Most of semiconductor device packages use epoxy-based resins with high moisture-absorbing property. Therefore, the semiconductor devices stored at high humidity may cause deterioration in the characteristics and rust on the terminals. In particular, please note that the semiconductor devices packed in moisture-barrier materials are easily affected by humidity. Under an environment where humidity is at or below 30% to 40%, a rapid and large increase in electrostatic charge generation tends to occur. This may result in permanent damage to our semiconductor devices during unpacking operation.

2) Atmosphere

Please store our semiconductor devices in an environment that generates no toxic gases and less dust.

3) Direct Sunlight and Condensation

Please store our semiconductor devices in a place that avoids direct exposure to sunlight and the occurrence of condensation. In case of direct sunlight exposure, a temperature rise in packing boxes may occur, thus resulting in the deformation of storage containers (e.g., stick magazines, taping materials), or the condensation due to a rapid change in temperature. Please also note that a storage place near the lights that generate heat may cause the same conditions as those by direct sunlight.

4) Stress

The precautions for transportation are required for proper storage considering stress. Please note that mishandling (e.g., placing an outer shipping box upside down, or leaving it tilted) may cause stress improperly applied to our semiconductor devices. Such stress may thus affect the quality of the semiconductor devices packed inside the box, including terminal deformation and package damage. Please also consider avoiding overload due to excessive stacking.

4.2 Long-term Storage

Long-term storage may lead to rust formation on the terminals of our semiconductor devices or deterioration in solderability. For the semiconductor devices stored for a long term (1 year or more), please check the following before use: discoloration or rust formation on the terminals; any quality problems in solderability. For the semiconductor devices expected to be stored for 1 year or more, our recommendation is to take moisture-proof measures such as using airtight containers or vacuum-sealed bags.

4.3 Products Packed in Moisture-barrier Materials

After opening a moisture-barrier bag, please use the semiconductor devices inside within the expiration date (floor life) while storing them in a specified environment (refer to IPC/JEDEC J-STD-033). For moisture-sensitive semiconductor devices like LEDs, please use them within the expiration dates specified in related documents such as a specification. For the semiconductor devices once unpacked and expired, please be sure to perform a dry treatment (e.g., baking) before use.

4.4 Products Packed in Taping Materials

The tapes used for packing our semiconductor devices may change in adhesive strength. Therefore, please use the semiconductor devices packed in taping materials within the expiration date (floor life). After pulling the tapes out of their reels, please wind the tapes back onto the reels before storage. Please do not bend the tapes excessively. For the semiconductor devices (e.g., surface mount components) moisture-proof packed in taping materials, please also see Section 4.3, “Products Packed in Moisture-barrier Materials.”