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bonding:removal [2020/04/30 22:33] – [Gold bond wire: amalgam] mcmasterbonding:removal [2020/10/25 06:06] (current) mcmaster
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   * Gold wire: use mercury or shear   * Gold wire: use mercury or shear
   * Copper wire: moderate strength nitric acid (say 50%)   * Copper wire: moderate strength nitric acid (say 50%)
 +
 +2020-10-24: I've had good luck with swab method. It might see more use moving forward
  
  
 ====== Mechanical methods ====== ====== Mechanical methods ======
 +
 +===== Swab =====
 +
 +I've had good luck removing bond wires using optical cleaning swabs. They are soft and don't damage the die surface, but bond wires tend to get caught on them. This allows bond wires to be quickly pushed off without scratching the die. In theory the gold could scratch the surface, but as long as light pressure is used they shouldn't be able to press in
  
 ===== Ultrasound ===== ===== Ultrasound =====
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 ===== Gold I/NaI  ===== ===== Gold I/NaI  =====
  
-https://twitter.com/lukeweston/status/1253256917457137664?s=20+TLDR: not recommended. Eats aluminum 
 +  * Details w/ references: https://twitter.com/johndmcmaster/status/1256773931807043585
  
-Mix+https://twitter.com/lukeweston/status/1253256917457137664?s=20
   * 2.5 g I   * 2.5 g I
   * 10 g NaI   * 10 g NaI
   * 100 mL H2O   * 100 mL H2O
  
 +https://www.inrf.uci.edu/wordpress/wp-content/uploads/sop-wet-gold-etch-using-potassium.pdf
 +  * 0.5 – 1 um/min at room temperature
 +  * mix
 +    * 1 g I2 (solid)
 +    * 4 g KI (solid)
 +    * 40 ml DI water 
 +  * glass or poly bottle
 +
 +
 +https://www.sigmaaldrich.com/catalog/product/aldrich/651818?lang=en&region=US
 +  * Etch rate of 28 angstrom/sec @ 25 °C.
 +  * Synonym: Antistrumin, Potassium monoiodide
 +
 +http://engineering.tufts.edu/microfab/documents/sop_goldetch.pdf
 +  * Has temp etch curve
 +  * 30C: 400 um / min
 +  * 45C: 800 um / min
 +  * 60C: 1500 um / min
  
 ===== Gold NaCN ===== ===== Gold NaCN =====
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 Move to PTFE watch glass + heatgun from solder pot Move to PTFE watch glass + heatgun from solder pot
 +
 +Notes
 +  * teflon melting point 620F (327C)
 +  * 770F heatgun => 415F blob?
 +  * 2020-05-04: 770F => 441F measured
 +  * 60/40 melts around 190C => 374F
  
 ===== Gold lead ===== ===== Gold lead =====
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 Worked okay, but seems to slightly wet SiO2, leading to a lot of hard to remove metallic residue. Worked okay, but seems to slightly wet SiO2, leading to a lot of hard to remove metallic residue.
  
-2020-04-30+2020-04-23 
 +  * https://twitter.com/lukeweston/status/1253256917457137664?s=20
   * Tried fluxing, much better. But not better than solder   * Tried fluxing, much better. But not better than solder
   * Above older picture though looks like it might be more gentle, possibly ok for rebonding   * Above older picture though looks like it might be more gentle, possibly ok for rebonding
bonding/removal.1588286017.txt.gz · Last modified: 2020/04/30 22:33 by mcmaster