Intel® Pentium® 4 - Little Black Hole on top?

David Maynard wrote:
 > To let the air and potentially excess goo out when they
 > slap the lid on the package.

And to vent warp plasma?
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

"Wayne Youngman" wrote in message

 > Hi,
 >
 > having just installed my first P4, there is something I wasn't sure of.
 > What is that little black hole on the upper surface of the CPU?. I was
 > worried about getting any AS/3 into it when I was applying the thermal
goo.
 > . .
 >
 > thanks,

A short way down the page:

<a rel="nofollow" style='text-decoration: none;' href="http://tech-report.com/reviews/2001q1/pentium4/index3.x" target="_blank">http://tech-report.com/reviews/2001q1/pentium4/index3.x</a>

Quixote
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

"David Maynard" wrote
 > To let the air and potentially excess goo out when they slap the lid on
the
 > package.


Hi,
you got me there? care to elaborate?
--
Wayne ][
<Sign on door reads: Please Do No Disturb! Pentium 4 assembly in progress!>
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

Intel puts it there to let the smoke out ;-0
--
Tally Ho!
Ed,
Maryland, USA
"Wayne Youngman" wrote in message

 > Hi,
 >
 > having just installed my first P4, there is something I wasn't sure of.
 > What is that little black hole on the upper surface of the CPU?. I was
 > worried about getting any AS/3 into it when I was applying the thermal
goo.
 > . .
 >
 > thanks,
 > --
 > Wayne ][
 > <Sign on door reads: Please Do No Disturb! Pentium 4 assembly in
progress!>
 >
 >
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

Fishface wrote:
 > David Maynard wrote:
 >
  >>To let the air and potentially excess goo out when they
  >>slap the lid on the package.
 >
 >
 > And to vent warp plasma?

Of course. And a dern good thing too because there aren't many things worse
than warp plasma buildup under your heat spreader.
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

Underneath the cap is usually quite a large splodge of material that
Intel use for both (obvious) conductivity & adhesion to stick it on.

Future caps will probably be different, using an interesting idea
where standoffs are used which ironically reduces hotspots:
o A heatspreader itself has to be well machined to contact the core
---- suffers the same touches-at-3-points as a heatsink to spreader
o Despite this you get hotspots regularly re spreader to core
o Solution is to use 4 or 9 standoffs between spreader & core
---- the standoffs have a thinner layer of adhesive than a spreader
---- gaps between the standoffs have thicker adhesive conversely

Ironically it reduces hot-spots quite considerably, beyond 9 standoffs
the benefit deteriorates rapidly as you tend towards a heatspreader.

It's a cheaper solution than another alternative to hotspots solved by
"wasting" silicon space. For example hot areas in the middle of a die
can conduct heat thro the substrate in 4 directions, those hot areas on
the edge can only conduct in 2 directions - a solution posted is to use
bare silicon (eg, 1mm) to drastically mitigate the W/mm^2 problem.
Sounds easy, but on a wafer you're wasting real-estate and so the
standoff solution might be engineered with the die thermal profile.

So in the future that heatspreader may get even more important.
--
Dorothy Bradbury
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top? 

See, it's like building a ship in a bottle. First you get the CPU package,
then you assemble the transistors and conductors with tiny tweezers through
the hole. That's why going to smaller feature sizes make CPU's cheaper!

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."

"Wayne Youngman" wrote in message

 > Hi,
 >
 > having just installed my first P4, there is something I wasn't sure of.
 > What is that little black hole on the upper surface of the CPU?. I was
 > worried about getting any AS/3 into it when I was applying the thermal
goo.
 > . .
 >
 > thanks,
 > --
 > Wayne ][
 > <Sign on door reads: Please Do No Disturb! Pentium 4 assembly in
progress!>
 >
 >
 >> Stay informed about: Intel® Pentium® 4 - Little Black Hole on top?