Die preparation is one step of the process that is used in semiconductor fabrication. During die preparation, it is necessary to properly mount and dice wafers. While there are several methods that can be used to mount wafers, using dicing tape is very common. Dicing tape is beneficial as it holds the die in place throughout the entire process. It is important to select the correct type of tape when mounting wafers in order to achieve the best results.
Types of Dicing Tapes
Standard tapes and UV release tapes are the two main categories of dicing tapes. Tapes may also come in different thicknesses and have different levels of adhesion. All characteristics of dicing tapes may have an effect on the way that the material is held and diced during processing.
Standard dicing tapes are generally blue in color and do not have a backing film. Standard tapes may vary widely in thicknesses, ranging from 80 microns to 130 microns. The adhesion level of standard tapes is measured in g/mm, with larger gram amounts making for stickier tapes. Standard tape is best for use in dicing wafers of standard thicknesses that are being diced into large pieces, as the pieces can usually be taken of the tape relatively easily.
UV Release Tapes
As implied by the name, UV release tapes do not allow materials to be released from the tape easily unless the tape is exposed to UV light. UV release tapes are usually clear and come in a large variety of thicknesses. The adhesiveness of the tapes may vary and may affect how easily the material is released from the tape even after UV exposure. UV release tape may be beneficial when dicing thicker wafers, as the pieces will be more likely to stay adhered to the tape throughout the entire process of dicing, whereas thicker pieces may come of when standard tape is used. If the adhesion level is high, UV release tape may not be ideal for thinner wafers or more fragile materials, as these materials may be difficult to remove after dicing and breakage may occur.
Thickness of Tape
The thickness of the dicing tape is critical because it affects whether or not the appropriate cut depth can be achieved. When selecting tape thickness, the material thickness, material type, cut depth, blade thickness, and desired final die size should all be considered. Taking all of these factors into consideration when choosing dicing tape thickness and type can help to prevent breakage, waste, and frustration.
Curing Time Consideration
Most dicing tapes of any type or thickness will need time to cure prior to dicing. Four hours is the standard amount of time to allow the wafer to set on the tape in order to allow the wafer to properly adhere to the tape. If curing time is not allotted during the project, the wafer or die may come off of the tape, causing damage to the product.