[HN Gopher] How Foundries Calculate Die Yield
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       How Foundries Calculate Die Yield
        
       Author : klelatti
       Score  : 22 points
       Date   : 2024-09-15 18:37 UTC (4 hours ago)
        
 (HTM) web link (www.viksnewsletter.com)
 (TXT) w3m dump (www.viksnewsletter.com)
        
       | sevensor wrote:
       | The defect math is interesting, but process uniformity is more of
       | a killer than the author gives it credit for. Fantastic amounts
       | of ingenuity go into showerhead design, chamber design, and
       | minute changes to process conditions, not to mention maintenance
       | practices. We'd like to pretend the pattern and the process are
       | orthogonal, but they're coupled, and you might need to run 5C
       | colder for one product versus another simply because the material
       | exposed by the pattern loads the chamber differently. And how
       | about water spots? Wet processing leaves water spots, just like
       | you might see after washing your dishes. Huge source of defects,
       | and once again pattern dependent. Patterning usually leaves
       | alternating areas of hydrophilic and hydrophobic material, and
       | you have to somehow prevent water from beading up anywhere. Sure,
       | it starts out deionized, but it's got plenty of junk in it after
       | rinsing your wafers off.
        
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       (page generated 2024-09-15 23:00 UTC)