Dicing Solutions

Selecting the right dicing tape is crucial for the dicing process.  The right or wrong decision can make or brake  a project.  As you may be aware there are so many different choices, there is bound to be a tape for almost every application.  The important thing is to know the different characteristics of a particular tape and how it can be beneficial or counter effective for what you are doing.  There are two main categories when it comes to dicing tapes: Standard or UV release.  Most tapes are PVC based films and the adhesives that they utilize are acrylic.

Standard tapes: These tapes are usually blue in color and they do not have a backing film.  Which means that as you peel the tape the adhesive is exposed.  These tapes come in different thicknesses, from 80 microns to 130 microns, as well as different tackiness levels.  The adhesion level is measured in g/mm; the larger the number of grams, the tackier the tape is.  Mainly the difference between these tapes and the UV release tapes is that standard tapes do not need to be exposed to UV light in order to release the part.  This can be beneficial and not, depending on the application.  For example if you have a silicon wafer which is very thick and it is diced into very small pieces on standard tape there is a high probability of the pieces coming off the tape during the dicing process (disaster).  On the other hand if you have a wafer which is standard thickness and it is to be diced into relatively large pieces, it can be easily diced on blue tape and the pieces can be taken off the tape without a problem  and without UV exposure.  The type of material also needs to be taken in consideration since some materials are not so easy to adhere to.

UV release tapes: These tapes are usually clear in color and they come in many different thicknesses as well.  UV release tapes have a backing film which needs to be peeled off the tape before applying it to the material.  They also vary in tackiness before and after exposure to UV light.  This is important because in the event that you have a very thin wafer which needs to be diced into relatively small pieces, but the g/mm is high even after the exposure, you will still have problems picking those fragile pieces off .  Generally the UV release tapes are good when you want a strong adhesion during dicing but an easy release once exposed.

The thickness of the tape you choose  is very important because you want to make sure the appropriate cut depth can be achieved.  Making sure of this will alleviate all sort of problems in the final product.  How can you determine the right tape for you ?  The guidelines are: material, material thickness, desired cut depth, blade thickness, and final die size.  When you take in consideration these aspects it will help you to determine the right tape for your specific application.

An important thing to remember is that most of the tapes, whether they are standard or UV release tapes, need a curing time.  This means that they need to sit for some time ( at least 4 hrs ) before dicing.  This allows the adhesive to fully grasp, if you will, the material that needs dicing.  In countless occasions I have heard people complain that their parts are coming off the tape when they mount the wafer and start dicing right away.  Another thing that causes this is air bubbles that remain in between the part and the tape.

This subject is very difficult to cover and it definitely requires some homework from the user point of view.  I recommend talking to your provider of dicing tapes so that you may discuss the different options available to you and from there decide on the best one.

On another entry I will discuss another popular mounting technique which is the use of thermal bonding agents other wise known as crystal bond.

This entry was posted on Saturday, September 11th, 2010 at 1:08 am and is filed under Techniques and methods. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.