Clueless newbie question -- what has changed to make moistur

[William H. Maddox III]

Plastic packages have been used for years, but it is only very recently
that I've heard of moisture absorption becoming big issue. Clearly, with
such dramatic effects on reliability, it can't be that we just were ignorant
of a long-standing problem. What is it about these parts that causes the
moisture sensitivity, or why has it become such an issue recently?

--Bill

 

[Gregory C. Read]

The plastic packages used in through hole technology were never subjected to
the extreme temperatures of surface mounting. When a small amount of
moisture is absorbed and then heated during surface mounting, the package
can fracture or even explode when the moisture turns to steam.

--
Greg
readgc.invalid@hotmail.com.invalid
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"William H. Maddox III" <NOSPAMmaddox@NOSPAMtransmetaDOTCOM> wrote in
message news:1084578360.741900@palladium.transmeta.com...

Plastic packages have been used for years, but it is only very recently
that I've heard of moisture absorption becoming big issue. Clearly, with
such dramatic effects on reliability, it can't be that we just were
ignorant
of a long-standing problem. What is it about these parts that causes the
moisture sensitivity, or why has it become such an issue recently?

--Bill

 

[john jakson]

"William H. Maddox III" <NOSPAMmaddox@NOSPAMtransmetaDOTCOM> wrote in message news:<1084578360.741900@palladium.transmeta.com>...

Plastic packages have been used for years, but it is only very recently
that I've heard of moisture absorption becoming big issue. Clearly, with
such dramatic effects on reliability, it can't be that we just were ignorant
of a long-standing problem. What is it about these parts that causes the
moisture sensitivity, or why has it become such an issue recently?

--Bill

Actually its been an issue ever since plastic has been used atleast as
far back as I know 25yrs+. ofcourse the plastics are not your typical
"plastic" but are engineered to have the kinds of properties needed to
house ICs. They need to resist moisture, need to be strong enough, and
mustn't contain too much radioactive material, that was the big one
that cought DRAM folks off gaurd 20yrs ago when the US found out how
much better Japan was at packaging.

Theres far more to it than that, google chip packaging etc to find
more

regards

johnjakson_usa_com