Metallographic Lapping Film InformationDiamond, Silicon Carbide and Alumina Lapping Films
The applications for lapping films range from polishing semiconductor dies, fiber optics, optical components, ceramic capacitors, computer hard drive read-write heads, ceramic seals, etc. The main characteristic of lapping films is that they produce very flat surfaces, especially across materials with a wide range in hardness.
Lapping films consist of a polyester backing (typically 3 mils) on which the abrasive is rigidly fixed with an epoxy binder. The most common abrasives used for lapping films include diamond, silicon carbide, alumina and to a lesser extent ceria.
Diamond lapping films are precision coated abrasives using precisely graded diamond. A very flexible adhesive bonding agent is used which tenaciously hold the abrasive particles to the backing. This provides a tough, durable, tear-resistant abrasive plastic film which is waterproof and resistant to many solvents.
Diamond lapping films provide less polishing relief than intermediate rough polishing cloths and provide a fixed diamond grinding mode. Diamond lapping films are exceptional abrasives for preparing microelectronic materials for SEM and TEM analysis.
Silicon carbide lapping films are bonded or coated abrasive films of SiC designed so that the abrasive will have a large number of cutting points (negative abrasive rank angle). This is achieved by aligning the abrasive particles approximately normal to the backing. Note that coated abrasives are not quite coplanar, thus SiC papers produce the maximum efficiency (cut rate, stock removal and minimal damage) because new abrasive is exposed as the old abrasive breaks down.
Alumina lapping films consist of an aluminum oxide, which is a naturally occurring material (Bauxite). It exits in either the softer gamma (mohs 8) or harder alpha (mohs 9, 2000 HV) phase. Alumina abrasives are used primarily as a final polishing abrasive because of its high hardness and durability
Recommended Procedures (Lapping Films)
For plain backed diamond lapping films
- Wet the flat lap plate with water or a water/ surfactant solution
- Place the plain backed lapping film on the surface
- Roll out or press out any entraped air bubbles
- Apply necessary lubricant
- Begin polishing with lower force to avoid tearing film
- Clean specimen and film for final 10-15 seconds of polishing cycle
- Clean and dry specimens
- Place the PSA backed lapping film on the surface
- Apply necessary lubricant
- Begin polishing with lower force to avoid tearing film
- Clean specimen and film for final 10-15 seconds of polishing cycle
- Clean and dry specimens
Trouble Shooting for Lapping Films Polishing
| Symptom | Cause | Action |
|---|---|---|
| Coarse scratching | -Swarf build-up on the lapping film | -Use a lubricant with an appropriate surfactant |
| Tearing of pad | -Sharp specimen edges |
-Reduce intitial applied load so that the specimen edge does not cut the film. Gradually increase pressure during the lapping operation. -Dispense lubricant more frequently |
| Excessive relief or edge rounding |
-PSA backing providing too much flexibility (resiliency) -Lapping backing plate surface is not flat |
-Use a plain backed diamond lapping film -Use a flat lapping surface |
Diamond Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) |
Catalog Number (PSA backed) |
Color Code |
|---|---|---|---|---|
| 0.10 um Diamond Lapping Film | Up to 12-inches | DA-01 | DAA-01 |  |
| 0.25 um Diamond Lapping Film | Up to 12-inches | DA-025 | DAA-025 |  |
| 0.50 um Diamond Lapping Film | Up to 12-inches | DA-052 | DAA-05 | |
| 1 um Diamond Lapping Film | Up to 12-inches | DA-1 | DAA-1 |  |
| 3 um Diamond Lapping Film | Up to 12-inches | DA-3 | DAA-3 |  |
| 6 um Diamond Lapping Film | Up to 12-inches | DA-6 | DAA-6 |  |
| 9 um Diamond Lapping Film | Up to 12-inches | DA-9 | DAA-9 |  |
| 15 um Diamond Lapping Film | Up to 12-inches | DA-15 | DAA-15 |  |
| 30 um Diamond Lapping Film | Up to 12-inches | DA-30 | DAA-30 |  |
Diamond Lapping Film Lubricants
| Description | Quanitiy (oz) | Catalog Number |
|---|---|---|
| 32 oz Diamond Lapping Film Lube | 32 | LFL-032 |
| 1 gallon Diamond Lapping Film Lube | 128 | LFL-128 |
Silicon Carbide Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) |
Catalog Number (PSA backed) |
|---|---|---|---|
| 1.0 um silicon carbide | Up to 12-inches | SIC-001PB-3 | SIC-001PSA-3 |
| 3.0 um silicon carbide | Up to 12-inches | SIC-003PB-3 | SIC-003PSA-3 |
| 5.0 um silicon carbide | Up to 12-inches | SIC-005PB-3 | SIC-005PSA-3 |
| 9.0 um silicon carbide | Up to 12-inches | SIC-009PB-3 | SIC-009PSA-3 |
| 12 um silicon carbide | Up to 12-inches | SIC-012PB-3 | SIC-012PSA-3 |
| 20 um silicon carbide | Up to 12-inches | SIC-020PB-3 | SIC-020PSA-3 |
| 30 um silicon carbide | Up to 12-inches | SIC-030PB-3 | SIC-030PSA-3 |
Alumina Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) |
Catalog Number (PSA backed) |
Color Code |
|---|---|---|---|---|
| 0.05 um alumina (ALO) | Up to 12-inches | ALO-105PB-3 | ALO-105PSA-3 |  |
| 0.30 um alumina (ALO) | Up to 12-inches | ALO-103PB-3 | ALO-103PSA-3 |  |
| 1.0 um alumina (ALO) | Up to 12-inches | ALO-001PB-3 | ALO-001PSA-3 |  |
| 3.0 um alumina (ALO) | Up to 12-inches | ALO-003PB-3 | ALO-003PSA-3 |  |
| 5.0 um alumina (ALO) | Up to 12-inches | ALO-005PB-3 | ALO-005PSA-3 |  |
| 9.0 um alumina (ALO) | Up to 12-inches | ALO-009PB-3 | ALO-009PSA-3 |  |
| 12 um alumina (ALO) | Up to 12-inches | ALO-012PB-3 | ALO-012PSA-3 |  |
| 15 um alumina (ALO) | Up to 12-inches | ALO-015PB-3 | ALO-015PSA-3 |  |
| 30 um alumina (ALO) | Up to 12-inches | ALO-030PB-3 | ALO-030PSA-3 | |
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