Differences

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--- equipment:lapping:type [2014/10/12 01:24] – mcmaster
+++ equipment:lapping:type [2015/06/30 16:05] (current) – [Platen] mcmaster
@@ Line 1: / Line 1: @@
+Lapidary machine: more proper name referring to use on rocks.  Tend to be less precise or more like faceting machines
+Cabbing/faceting machine; instead of arm support has a post with a precise angle adjustment and holder.  This might make a good DIY conversion route
 ====== Setup types ======
+There are various ways to mount samples based on what you need to do and how much you are willing to spend.
+===== Parallel polishing =====
+{{:delayer:lapping:sbt_bottom.jpg?300}}
+This site focuses on IC analysis.  Therefore the site focuses on this type
+This type of fixture can be identifed by a surface to affix a sample to.  Typically this is a stainless surface with indentation marks on it to help wax/glue grip better.
+{{:delayer:lapping:sample_triangle_zoom.jpg?300}}
+Above: fixture close-up showing wax grooves
+==== Standard ====
+A piston slips up/down.  The angle at which the piston contacts the platen is not adjustable.
+==== Three point ====
+Like above but the piston angle is adjustable.  This allows more precision and is easier to setup.
+=== Overhead arm ===
+{{alliedhightech:15-2000-gi:multiprep_2014.jpg?300}}
+Above: Allied High Tech 15-2000-GI [http://www.alliedhightech.com/Equipment/multiprep-polishing-system-8|Source]
+A motorized arm is suspended above the platen.
+Example: Allied High Tech 15-2000 MultiPrep System
+Advantages
+    * Less force on platen than side arm design
+    * Easier to control force?
+Disadvantages
+    * Parts are usually machine/manufacturer specific
+    * More limited selection
+=== Side arm ===
+The three point polisher is a stand alone object that can be moved from one machine to another.  The fixture itself is ground and thus must have tungsten carbide or other hard pads on the bottom to ensure long life.  A motorized arm is attached to the machine and turns the fixture via a rubber wheel in contact with the fixture.
+Example fixture: Logitech PP6, South Bay Technology 590
+Example machine: Logitech LP50, South Bay Technology 920
+Advantages
+    * Machine agnostic: can be used on many different lapping machines
+    * Higher precision?
+    * Simpler
+    * Somewhat scalable: larger size generally yields higher precision
+Disadvantages
+    * Fixture itself is lapped: more powerful machine required and degrades fixture over time
+    * Tend to be larger than overhead arms
+    * Larger fixture: larger lapping machine required
+    * Force can be harder to control: typically adjusted by applying weights \\       * Pneumatic versions exist
+===== Perpendicular polshing =====
+Designed to polish a thin slice of material at right angle to high precision.  Use, for example, to see how IC layers stack up.
+===== Sectioning =====
+Makes a highly polished surface to allow looking at, for example, a weld under a SEM or optical microscope to observe grain boundries.  Unlike parallel polishing, these do not have tight control over the angle at which they are polished.
+Typically specimins are mounted in epoxy and then bolted into a tear drop shaped fixture.
+===== Wafer =====
+Used for polishing entire wafers, typically for IC manufacturing.  These machines tends to be very large
+They can typically be identified by having gears and large circular cutouts to hold various size wafers
+===== Cast iron =====
+This isn't a machine so much as a platen that is used manually.  Seen entry below
+===== Faceting =====
+Intended for cutting gemstones (ex: diamonds) into shapes for jewelry
+Faceting machines share much with lapping machines.  However, they trade more movement freedom for lower precision.  I'm unclear if a faceting arm can do reasonable parallel polishing
 ====== Machine ======
@@ Line 16: / Line 111: @@
     * Fixture drive motor: motor to put a controlled spin on lapping fixture
     * Slurry pump: recirculates CMP solution after coming off of the platen
-    * York support: keeps fixture in place so it doesn't spin off
+    * Support arm: turns fixture and keeps in place
     * Slurry reservoir: holds bulk of slurry solution
     * Slurry filter: filters out contamination so it doesn't scratch the sample
@@ Line 26: / Line 121: @@
     * Cast iron
-    * Diamond
+    * Diamond, Al oxide, etc film surface
     * Poromeric pad
-However, cast iron and diamond are too abrasive for IC RE and so only polymeric pads are typically used.
+Cast iron and diamond is generally too abrasive for IC RE.  Poromeric pads are standard issue and some Al oxides look suitable.
-Some machines can take magnetic apds such that one can switch, say, between a diamond and cast iron pad.  As you should really only be using polymeric pads this feature will probably be less useful.
+Some machines can take magnetic pads such that one can switch, say, between a diamond and cast iron pad.  If you are only using poromeric pads this feature will probably be less useful but could be if you are using films.
-{{gallery>:tutorial:lapping:layers.jpg}}
-Above: typical stackup seen on JM machine consisting of (top to bottom):
+==== Cast iron ====
-    * MTI 8" Poromeric Polishing Pad (PSA) for final polishing - EQ-PP-8PSA-PC
+{{:delayer:lapping:cast_iron.jpg?300}}
-    * Two 8" Mater Plate ( Backing Plate ) for PSA Diamond plate, Sand Paper & Polishing Pad - EQ-MBP-8-2
-    * CrystalMaster 8 master lap
-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.
+Above: cast iron lapping 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.
+Cast iron lapping plates are typically used with diamond paste to lap optics and metal surfaces smooth.  They don't seem to be appropriate for use on ICs.  I tried using CMP solution on a cast iron lapping plate and it noticeably corroded it within 10 minutes.
-===== York support =====
+===== Support arm =====
 {{:delayer:lapping:arm2.jpg?300}}
-Above: york support from Logitech lapping machine.  Note the screw on the side to make fine angle adjustments
+Above: from Logitech lapping machine.  Note the screw on the side to make fine angle adjustments
+aka:
+    * Logitech: ?
+    * MTI: york support
+    * South Bay Technology: yoke assembly
 Most machines have a stiff support arm with two rollers on it.  This allows the fixture to rotate along with the machine to evenly lap the sample (planetary motion).  They are usually attached to a sturdy post built into the machine
@@ Line 141: / Line 239: @@
 sive per sample.  It is intended for sectioning where the particular angle sectioned isn't important.  Therefore, its not suitable for parallel polshing.  Additionally, it uses high force and the the mix may need to be hot which can risk damaging specimens.  See for example MTI's compression mounting powder ([[http://mtixtl.com/compressionmountingpowder5lboptionalcolorofblackredgreen.aspx|EQ-HM-Powder5L]]) + sample press [[http://mtixtl.com/mp-300mountingpressformetallographicsamples.aspx|EQ-MP-300]].
-==== Cast iron ====
-{{:delayer:lapping:cast_iron.jpg?300}}
-Above: cast iron plate
-Cast iron lapping plates are typically used with diamond paste to lap optics and metal surfaces smooth.  They don't seem to be appropriate for use on ICs.  I tried using CMP solution on a cast iron lapping plate and it noticeably corroded it within 10 minutes.