Dear Mr.Joyce,
The "reflow soldering guidelines for SMT" is a book ? Or it is company's
manue ?
This informaiton is very useful , thank you !


James Wang

> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]]On Behalf Of Koo, Joyce
> Sent: Wednesday, March 08, 2000 10:32 PM
> To: [log in to unmask]
> Subject: Re: [LF] ReRe: [LF] SnCu
>
>
> The maximum reflow temperature post by chip manufactures.
> Following are few
> of examles of recommended soldering temperature for Plastic ICs:
> Intel (Microprocessor): Peak reflow temp. 205 to 225 C, @ 120 to 130 sec.
> Component body temp. Max. 220 C.
> National Semi: Peak reflow temp. max. 235 C@ 20 sec.  Recommended
> 220 C @ 5
> sec.
> Altera (FPGA): "Ideally, the leads should only be subjected to the peak
> temperature (220 C) for approx. 10 sec. to reduce the risk of
> damage to the
> solder and devices.  In addition, the device body temperature
> which may vary
> from the temperature of the leads by as much as 15 C----should not exceed
> 220 C."
>
> -All the infor. are from the manufactures' recommended "reflow soldering
> guidelines for SMT".
>
> Hopefully, this clear up the picture a little....
>                                                   joyce
>
> >>> David Gowlett 03/07 1:11 PM >>>
> Dear Dr. Mathias,
>
> The problem now facing the electronics industry is maximum
> temperature that
> electronic components can survive. I accept that changes to the design of
> circuit boards may help to reduce the degree of overheat.
>
> Can members of this forum provide any information as to the maximum
> temperatures that components can survive?
>
> Regards,
> David
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]]On Behalf Of Dr. Mathias
> Nowottnick
> Sent: 07 March 2000 16:23
> To: [log in to unmask]
> Subject: [LF] ReRe: [LF] SnCu
>
>
> Dear David
> In principle you are right. But sometimes it will be possible to solder
> also below the liquidus temperature. Indeed the amount of solid phase of
> SnCu2 at 235*C will be only in the range of 2% in the melt. You can
> calculate that by the lever rule with the phase diagram for different
> temperatures and compositions. From experience I can confirm, that we
> have soldered successful with a SnCu3 alloy at 240*C. But I like to
> concede, that this must not work for all assemblies.
>
> sincerely
> Mathias Nowottnick
> Group Manager Joining Technology
> Fraunhofer Institute IZM
>
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