The technology trend is everything getting smaller, however certain applications require dice extraordinarily thick materials, such as glass, quarts, ceramics, and some silicon. These applications range from making imprint masks, to making heat shields, and substrates that require an unusual or uncommon thickness.
What do we mean by extra thick material? Normally the standard thickness for any given material in the industry is about 0.021 – 0.029?, the extra think materials we try to address here is 0.100 – 0.250? in thickness.
Some challenges of dicing these types of thickness materials:
- Need to consider blade thickness and exposure.
It is likely that when dicing something that is 1/4 of an inch in thickness, a 3 or 4? diameter blade is needed. Also the thickness of the blade needs to be relative to the thickness of the material. The blade needs to be fairly thick in order to accommodate the spindle load that will be generated. A thickness of .020 – .030? is recommended for the blade. Now there are a couple of different techniques that one might use to accomplish this task and they will require different procedures as well as yield different results.
- Consider Multiple Passes
We recommend that when dealing with thicknesses of .060? and over, the dicing be done in multiple passes. This technique requires the blade to make several passes while gradually cutting the whole of the material. In other words the blade makes the first pass at say .015? into the material; on the second pass it knocks out another .015? and so on until the blade reaches beyond the tape and the cut is completed.
The draw backs are this process is very time consuming. Every cut has to be multiplied by the number of passes. And the blade tends to deviate during the first passes because of lack of support.
This can be remedied by using a different scribe blade. Instead of using blades that gives you the entire exposure needed, we recommend using one that has only about .050? of exposure. Scribe .040? into the material and make the trenches for all the cuts that need to be made. Once this process is done, switch to the blade that has the entire exposure and dice in multiple passes over the trenches that were created earlier. The second blade will tend to follow the scribe cut alleviating any waviness.
- Back side chipping
Another issue is that the bottom of the cut or the back side chips. Some of the causes are, improper cut depth, improper RPM or feed rate, and vibrations that occur while the last chunk of material is being knocked off on the last pass. There are no good solution for this problem, however buying choosing the right thickness of the tape could mitigate the problem. It’s better to choose a tape that is sturdy and does not allow for much vibration.
We recommend using a RPM of 15K for 3 and 4? diameter blades. We also recommend 20K for 2? blades and a feed rate of about .02? per second (depending on the specs and material). For glass and quarts we recommend using 325 grit size, for ceramic 270 and for silicon 3000 or larger.
If any questions on selecting the right blades, tapes for your task, please contact Dicing Blades engineer for recommendations.