[SI-LIST] Re: Current capacity of a Solder Ball
- From: Moses Chan <mchan@xxxxxxxxxxx>
- To: omism@xxxxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Wed, 05 Feb 2003 15:33:08 -0800
Hi All,
I agree with Ozgur and Pat. The current capacity is really governed by the
trace dimensions, or what ever bottleneck a VDD plane is experiencing. When
I asked the question a few months back I was comparing the capacity of the
ball against a solder bump.
I never did use the figures for the balls, as someone rightly pointed out,
it'll melt the substrate.
Regards,
Moses Chan
At 03:35 PM 2/5/03 -0700, Ozgur Misman wrote:
>Hi All,
>I certainly agree with some of the authors that the current carrying
>capability of a solderball can not be solely determined by considering the
>solderball as a seperate entity.
>The current capacity could mainly be influenced by the quality and the
>metallurgy of the Solderball/ soderballpad interface.
>My question would be whether the ball falls off before it melts?
>By the way, I have not come across any technical paper on this issue,
>although I have been looking for it for some time.
>If anybody has any reference that points out to measured data. PLease
>forward a copy to me , I would be very interested.
>Regards,
>Ozgur Misman
>
>
>
>
>
>
>Aubrey_Sparkman@xxxxxxxx@freelists.org on 02/05/2003 02:39:48 PM
>
>Please respond to Aubrey_Sparkman@xxxxxxxx
>
>Sent by: si-list-bounce@xxxxxxxxxxxxx
>
>
>
>To: weirsp@xxxxxxxxxx, mchan@xxxxxxxxxxx, BSchieck@xxxxxxxxxx,
> si-list@xxxxxxxxxxxxx
>cc:
>
>
>Subject: [SI-LIST] Re: Current capacity of a Solder Ball
>
>
>
>Steve,
>Let's assume that all your numbers are correct. I had the same conclusion
>several years ago at a previous company. We both missed the main point of
>Pat's email: You need to re-think what the limiting factor is. It's not
>immediately obvious.
>
>Aubrey Sparkman
>Signal Integrity
>Aubrey_Sparkman@xxxxxxxx
>(512) 723-3592
>
>
> > -----Original Message-----
> > From: steve weir [mailto:weirsp@xxxxxxxxxx]
> > Sent: Wednesday, February 05, 2003 3:07 PM
> > To: mchan@xxxxxxxxxxx; BSchieck@xxxxxxxxxx; si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Re: Current capacity of a Solder Ball
> >
> >
> >
> > Moses, and Brian, that current number seems low by orders of
> > magnitude. First, the electrical resistance is way off. For the
> > resistivity value shown which seems about right at 8X Cu, and
> > a rectangular
> > section 0.2mm X 0.2mm X 0.6mm yields about 0.002 ohms.
> >
> > Similarly, the thermal resistance value of 41,000 C/W for a
> > metallic object
> > 24 thousandths thick cannot be right. Take a small glob of
> > solder the size
> > of a BGA ball on the bench and connect it to a 10V supply and
> > a 100 ohm
> > resistor. There is no way, that blob will get warm, much
> > less melt. It
> > will take multiple amperes to melt the foil leading to or
> > away from the
> > ball, and the foil will fail long before the ball.
> >
> > Regards,
> >
> >
> > Steve.
> >
> > At 11:32 AM 2/5/2003 -0800, Moses Chan wrote:
> >
> > >Hi Brian,
> > >
> > >I asked the same question to the list a few months back and got the
> > >following answer, below:
> > >
> > >Solder Ball (63Sn/37Pb) 0.0006 m
> > >Ambient Temp. 34 Deg. C
> > >Melting Temp. 189 Deg. C
> > >Thermal Conductivity 50 W/m-C
> > >Electrical Resistivity 0.000000145 ohm-m
> > >Thermal Resistance 41026.51161 C/W
> > >DC Electrical Resistance 0.297442209 ohm
> > >Total Resistance 0.297442209 ohm
> > >Power to Melt 0.003778045 W
> > >Current to Melt 0.112702164 Amps
> > >
> > >
> > >Moses Chan
> > >Vitesse Semiconductor
> > >Camarillo, California
> > >
> > >At 11:13 AM 2/5/03 -0800, Brian Schieck wrote:
> > >
> > > >Does any one know what the current carrying capacity of a
> > solder ball is?
> > > >How is the capacity determined?
> > > >Is the capacity derated to account for temperature and voids?
> > > >
> > > >
> > > >for a 60 mil solder ball.
> > > >
> > > >Brian Schieck
> > > >NVidia Corporation
> > > >2701 San Tomas Expressway MS B22-221
> > > >Santa Clara, California 95050
> > > >Direct Phone # (408) 486-2697
> > > >Corp Phone # (408) 486-2000 x62697
> > > >Local Fax # (408) 486-8078
> > > >Corp Fax # (408) 486-2200
> > > >
> > > >Email bschieck@xxxxxxxxxx
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