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Moisture sensitive Devices

Ashok Dhawan

#7564

Moisture sensitive Devices | 8 February, 2000

I have three questions on moisture sensitive devices:

1. What is general practice on incoming / receiving inspection of moisture sensitive devices- which boils down to mostly FPDs and BGAs ? Traditionally, FPD packs were opened only at time of use but IPC STD 033 appears to be allowing all ( does not state clearly ) as resort to room temp desiccation as long as the exposure time is limited to max 8 hours. 2. New std IPC J-STD-033 states MBB with property WVTR as 0.002 while J-STD-786A specifies it as 0.020. When contacted MBB suppliers, they mostly states 0.020 in their spec sheet- can any one clarify ? I am also contacting IPC to check ? 3. As a user, what is general recommendation to reseal bags with ordinary bag sealer or vacuum sealer ? Why we need vacuum in any case. If it is moisture, wht not add extra desiccant to take care of moisture from entrapped air and unbaked carriers. IPC std does not address this query ?

Ashok

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#7565

Re: Moisture sensitive Devices | 9 February, 2000

Ashok: I have three answers to your questions on moisture sensitive devices:

1. What is general practice on incoming / receiving inspection of moisture sensitive devices- which boils down to mostly FPDs and BGAs ? Traditionally, FPD packs were opened only at time of use but IPC STD 033 appears to be allowing all ( does not state clearly ) as resort to room temp desiccation as long as the exposure time is limited to max 8 hours.

What no TSOPs or PQFPs? Opening at time of use can�t hurt, correct?

2. New std IPC J-STD-033 states MBB with property WVTR as 0.002 while J-STD-786A specifies it as 0.020. When contacted MBB suppliers, they mostly states 0.020 in their spec sheet- can any one clarify ? I am also contacting IPC to check ?

Nope. Talking to higher beings never hurts.

3. As a user, what is general recommendation to reseal bags with ordinary bag sealer or vacuum sealer ? Why we need vacuum in any case. If it is moisture, wht not add extra desiccant to take care of moisture from entrapped air and unbaked carriers. IPC std does not address this query ?

Pulling a vacuum could damage components, go widda bag sealer. Desiccant is difficult to control.

My2�

Dave F

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