Differences

This shows you the differences between two versions of the page.

--- delayer:lapping [2014/10/12 01:20] – mcmaster
+++ delayer:lapping [2019/06/26 14:18] (current) – [mcmaster notes] mcmaster
@@ Line 1: / Line 1: @@
+[[mcmaster:lapping|JM lapping R&D]]
 {{:tutorial:lapping:sram_top_metal.jpg?300}}  {{:tutorial:lapping:sram_lapped.jpg?300}}
@@ Line 74: / Line 76: @@
 If the surface has damage you may consider using fine grit sandpaper first
+====== Pads ======
+===== Poromeric example =====
+{{gallery>:tutorial:lapping:layers.jpg}}
+Above: typical stackup seen on JM machine consisting of (top to bottom):
+    * MTI 8" Poromeric Polishing Pad (PSA) for final polishing - EQ-PP-8PSA-PC
+    * 8" Mater Plate ( Backing Plate ) for PSA Diamond plate, Sand Paper & Polishing Pad - EQ-MBP-8-2
+    * CrystalMaster 8 master lap (aluminum platen)
+The first, the poromeric pad is the most important.  It is essentially a soft pad to move abrasive around without actually scratching the die.  The next forms a smooth surface on which the poromeric pad rests.  Finally, the master lap is the interface to the machine itself and has ridges to keep backing plate in plate.
+Originally the machine had a steel backed diamond pad directly on the master lap (attached with adhesive, removed with acetone + heatgun).  In this setup the steel backing is much stiffer than the polishing pad and so serves as the backing plate.
+===== Non-PSA =====
+Asked TedPella about how to use non-PSA pads:
+<code>
+Q: Re: Non-PSA lapping films
+How are these intended to be attached?
+I noticed they are lower cost but I don't understand how one would use them.
+Can you point to an example workflow/setup using them?
+A:
+Some polishers have a ring that fits on the disc and holds the  lapping film in place.
+You can also try applying  a thin film of water on the disc under the film.
+If moderate polishing pressure is used this method  is satisfactory.
+For  more aggressive polishing, a spray adhesive can be sprayed on the disc.
+The easiest  solution is to use PSA backed film.
+</code>
 ====== Abrasive (slurry) ======
@@ Line 294: / Line 331: @@
   - Run sample
     - Attach sample holder to jig
+    - Set jig 125 um off of surface
     - Stop machine
     - Quickly but carefully place jig onto pad
@@ Line 451: / Line 489: @@
-====== References ======
+====== mcmaster notes ======
-    * Parallel Lapping of Devices for Deprocessing: [[http://www.southbaytech.com/appnotes/57 Parallel Lapping of Devices for Deprocessing.pdf|http://www.southbaytech.com/appnotes/57 Parallel Lapping of Devices for Deprocessing.pdf]]
+g Al round block
-    * Beck's failure analysis chapter "The Surface-Parallel Planar Microsection" (page 139)
+  * P180 / 80 um used SiC: 140 mm3 / sec @ speed 3
-    * Allied Tech parallel lapping: [[http://jiam.utk.edu/new/PDF/Allied-Parallel-Lapping-Integrated-Circuits.pdf|http://jiam.utk.edu/new/PDF/Allied-Parallel-Lapping-Integrated-Circuits.pdf]]
+    * 460 - 423 = 37 um / min
-    * Allied Tech backside thinning: [[http://jiam.utk.edu/new/PDF/Allied-Backside-Thinning.pdf|http://jiam.utk.edu/new/PDF/Allied-Backside-Thinning.pdf]]
+    * 5.3 x 11.0 mm = 58.3 mm2
-    * [[http://www.southbaytech.com/applist.htm|http://www.southbaytech.com/applist.htm]]
+    * 37 * 4 * 58.3 = 8628.4 mm3 / min
+    * One die fractured after just one minute
+    * Probably too aggressive to use in practice
+  * 30 um new AO: 6.2 mm3 / sec @ speed 3
+    * Same area as above
+    * 1.6 um / min
+    * 1.6 * 4 * 58.3 = 373 mm3 / min
+Removing pads
+  * 300 F optimal
+  * By 350F glue is too soft to come off in one piece
+====== References ======
+  * Parallel Lapping of Devices for Deprocessing: [[http://www.southbaytech.com/appnotes/57 Parallel Lapping of Devices for Deprocessing.pdf|http://www.southbaytech.com/appnotes/57 Parallel Lapping of Devices for Deprocessing.pdf]]
+  * Beck's failure analysis chapter "The Surface-Parallel Planar Microsection" (page 139)
+  * Allied Tech parallel lapping: [[http://jiam.utk.edu/new/PDF/Allied-Parallel-Lapping-Integrated-Circuits.pdf|http://jiam.utk.edu/new/PDF/Allied-Parallel-Lapping-Integrated-Circuits.pdf]]
+  * Allied Tech backside thinning: [[http://jiam.utk.edu/new/PDF/Allied-Backside-Thinning.pdf|http://jiam.utk.edu/new/PDF/Allied-Backside-Thinning.pdf]]
+  * [[http://www.southbaytech.com/applist.htm|http://www.southbaytech.com/applist.htm]]
+  * Cabot Microelectronics "Professor polish" series
+    * [[https://www.youtube.com/watch?v=xQFjcqgGISw|Chemical Mechanical Planarization, CMP Process Fundamentals: Sec 1 - Intro to Chip Manufacturing]]
+    * [[https://www.youtube.com/watch?v=2z4lq-Ms_OU|Chemical Mechanical Planarization, CMP Process Fundamentals: Sec 2 - CMP Tools and Process]]
+    * [[https://www.youtube.com/watch?v=lWvvKGkFDfk|Chemical Mechanical Planarization, CMP Process Fundamentals: Sec 3 - CMP Slurries]]
+    * [[https://www.youtube.com/watch?v=gg0vlNsBWx0|Chemical Mechanical Planarization, CMP Process Fundamentals: Sec 4 - CMP Polishing Pads]]
+    * [[https://www.youtube.com/watch?v=OP6LP7oALTU|Chemical Mechanical Planarization, CMP Process Fundamentals: Sec. 5 & 6 - CMP Challenges & Summary]]
+  * https://www.rawscience.co.uk/pdf/single-die-hands-free-layer-by-layer-mechanical-deprocessing-for-failure-analysis-or-reverse-engineering.pdf
+    * Single Die 'Hands-Free' Layer-by-Layer Mechanical Deprocessing for Failure Analysis or Reverse Engineering
+    * Tony Moor, with support from Gatan (Eli Malyanker, Efrat Raz-Moyal)
+    * Talks about sacrificial dies and other issues
+    * Professional equipment