George of course is correct! 

You can also calculate the thickness of the intermetallic layer. The equation and constants are in a paper I presented at SMTA on HASL (back when it was all the rage) in 1990.

Best regards
Lee

J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389

----- Original Message ----- 
  From: George Milad<mailto:[log in to unmask]> 
  To: [log in to unmask]<mailto:[log in to unmask]> 
  Sent: Thursday, December 22, 2005 11:17 AM
  Subject: Re: [TN] Intermetalic Layer


  The copper tin intermetallic layer thickness will depend on reflow
  temperature and time at temperature.
  Note: the IMC will grow over time and will not stay fixed.
  We have data that was presented in the Lead free IPC/JEDEC conference showing
  the increase in IMC thickness when the joint is subjected to accelerated age
  testing, ( 150 deg C for up to 1000hours).



  Best regards

  George Milad
  National Accounts Manager for tTchnology
  Uyemura International Corporation
  240 Town Line Rd
  Southigton, CT06489
  860 793 4011 (O)
  516 901 3874 (cell)
  [log in to unmask]<mailto:[log in to unmask]>

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