Technical Information

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Seiko Epson's plastic-molded LSIs are designed and manufactured for trouble-free operation when used under normal operating conditions. All products are subjected to stringent electrical and mechanical testing to ensure reliability.
When working with our products, you should take the following precautions.

Moisture absorption and Reliability

Standard storage conditions and storage periods for IC package

The resin used in plastic packages absorbs moisture over time even stored in room conditions. Where an IC package is done reflow soldering with much moisture absorption, the resin may have a crack or a delamination between the resin and lead frame may happen. Consequently, certain storage conditions should be maintained prior to reflow soldering. The table below shows the allowable storage conditions for plastic packages.
Always store packages in an environment that satisfies these conditions.

Standard storage conditions and storage periods for IC package

List of storage ranks and storage conditions

Storage rank Storage environments after opening the bag
SE1(equivalent to JEDEC MSL2) 30°C, 85%RH or less Within 12 months (1 year)
SE2 (equivalent to JEDEC MSL2a) 30°C, 70%RH or less Within a month
SE3 (equivalent to JEDEC MSL3) 30°C, 70%RH or less Within 168 hours (1 week)
SE4 (equivalent to JEDEC MSL4) 30°C, 70%RH or less Within 72 hours (3 days)
  • Allowable storage duration before opening the bag (sealed moisture proof bag): 12 months in 30-C, 85%RH or less
  • If reflow is to be carried out multiple times, it should be performed within the storage period specified at the corresponding package rank. (Reflow can be performed up to two times)
  • When the storage duration after opening the bag has been exceeded or it has become unknown, carry out mounting after re-baking.
  • Regarding the storage rank of respective products (IC packages), please refer to the PKG profile of Package Lineup.

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Package baking conditions

Packages which exceed the recommended storage conditions should be baked before reflow soldering. This baking process will prevent the resin from cracking during soldering.Meanwhile, baking should be done up to 2-times under the following conditions.

Standard baking conditions for IC packages
Baking temperature Baking hours
125±5°C 20 hours or more and 36 hours or less

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Soldering precautions

When soldering surface mount devices under methods wherein the whole packages get heated such as infrared reflow and air reflow, observe the following conditions. Such soldering may be carried out up to 2-times only. Meanwhile, pay extra attention to the storage conditions since moisture-absorbed plastic packages tend to cause quality problem such as crack.

Infrared reflow, and Air reflow

  • Temperature profile --- The temperature profile (on resin surface) of the reflow furnace should be within the allowable package heat-resistant temperature profile described below.
  • We recommend soldering work to be carried out in the shortest time at the lowest temperature in terms of reducing the thermal stress to packages. Settings of the soldering profile should be performed upon through confirmation that the state of soldering and reliability after soldering are optimized.
  • Regarding the corresponding profile level of respective products (packages), please refer to the PKG profile of Package Lineup. (The following allowable temperature conditions may not apply to some of our products.)

Hand soldering

Hand soldering using a soldering iron should be performed under the following conditions.

  • Maximum temperature of the soldering iron: 350ツーC (within 5 sec per pin)
  • Pay sufficient attention not to let a soldering iron contact any parts other than leads, such as a package body.

Flow soldering

For flow soldering, please contact your Epson sales representative.

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Handling and operating precautions

Storage condition

  • Take care so that packages are not subjected to impact, vibration or water leakage.
  • Do not store and use the product under conditions where moisture condensation may be formed due to rapid changes in temperature. Also, do not put load on products.
  • When storing, avoid dusty locations or locations with corrosive gases.
  • After a long period of storage, check to see that the pins are not discolored, solderability is not degraded, etc., before use.
  • Check moisture-proof bags for tear or wear before use. Also check the silica gel in the bag has not ab-sorbed moisture when the bag is opened.
  • Storage conditions after opening a moisture proof-bag, soldering method and soldering temperature must meet the requirements specified by Epson for respective products.

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Conditions of use environment

  • Precautions for use environment Use the IC in the proper temperature and humidity. The humidity must be 85% or lower (to prevent dew condensation). In the environment where the IC is directly exposed to dust, salt, or acid gas such as SO2, it may cause electrical leakage between leads or corrosion. In order to prevent such problems, apply corrosion-proof coatings to printed circuit boards and ICs.
  • Protection against excessive physical stresses and rapid temperature change Do not expose ICs to excessive mechanical vibration, repetitive shock stress, or rapid temperature changes. These can cause the plastic package resin to crack and/or the bonding wires to break.

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Cautions to be observed when designing

  • Use within the rated ranges
    Use ICs not to exceed the rated ranges of operating voltage, temperature, input/output voltage and current. Devices may sometimes work properly for a short period of time even when used outsie the rated ranges, but their failure ratio may increase. Even within the rated conditions, failure ratio will change depending on the operating temperature and voltage of embedded systems. This must be fully considered when designing systems.
  • Handling of input/output control pins
    When a noise such as spark and electrostatic is given from an input or output terminals, IC may malfunction. Pay sufficient attention in product designing. Electromagnetic interference can cause ICs to operate erratically. Shield all interference sources in equipment that uses ICs.
  • Latch up phenomenons
    Excessive electrical noise occurred to a power or input/output pin can cause ICs to latch up, resulting in device malfunction or damage. If this occurs, turn off the power, isolate the problem, then supply power again.
  • Protection against electrostatic discharge (ESD)
    Although all pins are equipped with an anti-electro static circuit, electro static beyond the capacity may lead to breakage. Take appropriate countermeasures when handling ICs.
  • Avoid using packing and transporting containers made of plastic. Use electrically conductive containers. Also, special care must be taken when handling ICs, by wearing a antistatic wrist strap or taking other possible measures.
  • Use a soldering iron and test circuits without high voltage leakage with grounding.

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Light shading precaution

Exposing semiconductor devices to the light may have a chance to lead to miss function, since the light affects the device characteristics.To prevent IC from miss function, please take into account the following points about substrates and products, packaged with IC.

  • At product design and assembly, please consider the product structure so that IC is shaded in actual use.
  • At testing process, please provide shaded environment for the device under test.
  • Please consider surface, back and side of IC chip, since IC should be shaded entirely.

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Bare chip precautions

General precautions

  • The passivation film applied on bare chip surface is not to protect the chip from external shock but to protect the internal metallization.
  • Moisture and dust in the air and careless handling of products during assembly will lead to defective products. Adequate caution must be exercised for storage environment and chip handling.

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Packing

When bare chips are shipped, they are put in dedicated trays, and the trays are clipped so that chips are properly held in the trays during transportation. Then the trays are packed in antistatic bags. Do not open the bags more than necessary to prevent foreign substances from coming into the bags and falling on the chips inside. Do not leave trays open, either.

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Bare chip storage precautions

  • Allowable storage periods before and after opening the pack are maximum 12 months under the conditions mentioned below.
  • If the bags are opened, assemble the products without much delay in order to prevent the bonding degradation caused by the quality change in the bonding pad surfaces.

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Bare chip storage conditions and storage periods

State Storage conditions Allowable storage period
Before opening Lower than 35°C, 80%RH point 6 months
After opening Lower than 30°C, 80% RH point 30 days
In dry N2 gas with dew point lower than -30°C 6 months

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Bare chip mounting

  • Mounting environment
    Perform bare chip mounting in the clean environment where chip surface is not exposed to contaminated air or substances.
  • Die pick up method
    It is recommended to use a die for picking up a die. Choose die collets that can minimize the contact area on the chip.
  • Mount boards (PCBs, etc.)
    Use boards where no residues such as chemicals are or conductive failure (such as bonding failure) or Al pad corrosion may occur.
  • Pick up tool control
    Clean the pick up tool periodically. Any foreign substance attached to the will lead high rate of continuous failures.
  • Bare chip cleaning
    Do not clean bare chips. If bare chips are cleaned, extreme caution must be exercised about residues on chips.
  • Protection from static electricity
    Use products in the environment where they are not exposed to ESD. When mounting a bare chip, mount it after assembling all other peripheral parts.

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Material

For mold resins, use "semiconductor grade"products. This is recommended to prevent corrosion in bonding pads due to moisture absorption, or the mold resign internal stress due to temperature changes. Similar pre-cautions must be taken for other materials to be used.

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