BGA Processors

[Philippine Mango]

with intel's LGA 775 processors it makes you wonder "why can't they make a BGA processor"? That way they wouldn't have to have pins and would be less likely to break. Is there a minimum to it's size or something?

 

[PrinceXizor]

Sure thing...let me run my newly purchased processor through my surface mount machine using x-ray to properly line-up 700 solder balls with the appropriate pads on the motherboard.

Unless...you meant something different? Processors are socketed for easy installation and removal.

P-X

 

[Peter]

BGA processors are good for soldering directly onto the mainboard, which really isn't an option for the end user.

 

[Philippine Mango]

Well I remember some where they discussed BGA type processors where they would have "little solder balls" on the processor and just have an opposite end on the board or vise versa like with LGA 775, little balls on the board and connections on the bottom of the processor. It would be much more difficult to damage/rip off one of them if they are on the processor.

 

[BEL6772]

BGA processors are possible ... there's no 'can't' about it. They don't do it becaue their customers don't want it.

 

[kpb]

They do make BGA processors. They come pre soddered onto the mb with things like the VIA eden processors. You can't buy an intel like that because they want to be interchangable and not permanantely attached to the MB for upgrades, variety of speeds etc.

 

[Philippine Mango]

Well it was discussed that it would be of a BGA type.

 

[PottedMeat]

like this?BGA Socket

only ~$500

LGA maybe the best of both worlds - shorter interconnects (from BGA) and swapability -may not be a word (inexpensive and hard to screw up)

 

[Peter]

Those BGA sockets are for prototyping. Intel, AMD and VIA do supply BGA form factor processors, and have done so for a long time - they're for the embedded, extremely small form factor, slimline notebook, and ruggedized computer market. You can't ever upgrade your processors in those, ever.

 

[canadageek]

yeah, but a bga cpu on a socket made up of hemispheres makes sense in that one would have to try HARD to bend or break the contacts

 

[Peter]

And try a lot harder to get proper contact. How'd you deal with surface planarity/warping? That's already difficult enough when getting 700 to 1100 balls to melt down properly - if you're trying to mate hemispheres without any spring element whatsoever, you're not going to make proper contact.

 

[bobsmith1492]

You could attatch small heaters on the motherboard that melts the solder slightly on each 'pin' in order to make contact. Practical? No. Necessary for ball contacts?? Probably.

In the same line though, how do the new pentiums do it? Don't they have a similar setup where the motherboard pins simply hit the processor straight-on? They should have simlilar problems I'd think.

 

[PrinceXizor]

While I've never seen the new Pentium chipsets up close, it seems from the pics that there is a mechanical connection....i.e. it might not be much, but there is still a protrusion mating to cavity type of situation going on. Much different than hemispherical solder balls joining to a flat surface (that could be not flat as Peter mentioned already). Your standard BGA machine has some type of x-ray facility so that you can verify alignment of your BGA chips. They are not cheap, which is why my company hasn't transitioned to BGA chips yet for our controllers (though we're just about being forced to by chip mfg).

Certainly, not a consumer/end-user or even system builder option.

P-X

 

[Peter]

Originally posted by: bobsmith1492
You could attatch small heaters on the motherboard that melts the solder slightly on each 'pin' in order to make contact. Practical? No. Necessary for ball contacts?? Probably.

In the same line though, how do the new pentiums do it? Don't they have a similar setup where the motherboard pins simply hit the processor straight-on? They should have simlilar problems I'd think.

You don't have the faintest idea about how much heat it takes to solder up properly, do you? And how closely together soldering temperature and dead-chip temperature are?

BGA is not for DIY. End of story.

 

[bobsmith1492]

Yes, actually I do; I'm actually an electrical engineer. It was a joke Pete - chill out!

 

[Peter]

'kay ... you were too close to the spirit of the original question though

 

[bobsmith1492]

Eh, it's all good....