Pressure-Sensitive Adhesive Tape for
Water Jet-Guided Laser Dicing Process

1.

INTRODUCTIONAs semiconductor devices improve in packing density inthese years, the size increase and thickness decrease ofwafers is proceeding worldwide, requiring also improvements of tapes for semiconductor use in terms of function
and performance. Thus in the wafer dicing process wherea blade-cut method is generally applied using a dicer or aslicer, it is anticipated that "chipping" of wafers becomes
more likely to occur when silicon wafer substrates of small
thickness undergo dicing.
Laser µJet Dicing is drawing attention as a new dicing
method that can suppress chipping. Figure 1 shows theprinciple of Laser µJet Dicing in which a water jet several
tens of µm in diameter is used to guide a laser beam todice the wafer. This technology, owned by Synova ofSwitzerland, is expected to significantly reduce chipping
compared to the conventional blade-cut dicing.
In terms of adhesive tapes for wafer dicing, whereas
ultraviolet curing (UV) tapes of UC series could be used inblade-cut dicing, these have to be improved in performance so as to be applicable to Laser µJet Dicing. This
report describes the features of Laser µJet Dicing together
with the detailed performance of pressure-sensitive adhesive tape developed at this time for this technology.

2.

FEATURES OF LASER µJET DICING

Laser µJet Dicing can cut wafers in a non-contact manner.
Because of this, the method is expected to offer the following advantages when applied to the dicing of thin
wafers.
1) It can drastically reduce the mechanical stress on thework, suppressing occurrence of chipping or microcracking.
2) Cutting speed can be significantly increased.
3) It prevents breakage of wafers likely to be induced byblade-cutting, thus eliminating problems of quality
degradation. Moreover, the exchange, adjustment etc.
of blades becomes unnecessary.
4) Scribe lines can be made narrower.
5) Because water jet is used as a guide, it cools off theheat in wafers generated during dicing, reducing thermal loads. In addition it suppresses occurrence ofcontamination, thus facilitating subsequent cleansing

50 µ m approx.
Laser µJet
Laser beamWork to be cut(Wafer)
Laser µJet

Work to be cut(Wafer)

Adhesive tape for
Laser µJet Dicing
Adhesive tape for Laser µJet Dicing
Dicing frame
Vacuum chuck table

Figure 1

Principle of Laser µJet Dicing.

work.
6) Because the laser light source can be moved in thex- and y-directions, cutting along a curved line is feasible.

3.

PERFORMANCE OF ADHESIVE TAPE
FOR LASER µJET DICINGIn Laser µJet Dicing the water jet several tens of µm indiameter used for guiding the laser beam impinges upon
the work. Therefore, an adhesive tape for dicing isrequired to allow the water jet to pass through from thescribe line to the rear surface of the tape, i.e., the substrate film of the tape has to be provided with micro
through-pores. The developed adhesive tape is made ofsuch materials as with the following characteristics.
1) Not to be damaged when irradiated by a laser beam.
2) The tape has to be pervious to water.
3) To eliminate chipping during dicing.
4) Not to give forth fibrous elements during cutting.
5) To suppress transfer of adhesives on to the rear surface of the chip at pick-up.
6) The tape has to be uniformly expandable.
The adhesive tape for Laser µJet Dicing is designed
using an adhesive that is based on a UV-curable adhesive, realizing a strong adhesion holding the work during
dicing together with easy peeling when irradiated with UV
after dicing. Table 1 shows the adhesive strength of the1

Table 1

Adhesive strength of adhesive tape for Laser µJet
Dicing.

Product FS-1006

FS-1006

FS-1063

FS-1076

Before UV

2.20

1.85

2.80

After UV

0.41

0.50

0.39

Before UV

1.071.03

1.63

After UV

0.21

0.190.12

on SUS
Adhesive force(N/25 mm)

on Si

Note 1: The figures represent typical values, not guaranteed values.
Note 2: Measuring conditions for adhesive force are as follows.
Test surface: SUS304 surface polished with #280 or Si wafer with mirror surface
Peeling angle: 90°
Peeling speed: 50 mm/min
UV irradiation: 1000 mJ/cm2

tape, demonstrating a significant decrease in adhesion
force after UV irradiation. Photo 1 shows that the chippingon the rear surface of a wafer has disappeared by Laserµ Jet Dicing using the developed tape, resulting in asmoothly cut surface.

4.

IN CONCLUSION

We intend to develop hereafter innovative adhesive tapes
best suited for Laser µJet Dicing, focusing on upgrading offunctions such as expandability. For detailed information,please refer to the following.
For more information, please contact:Development Group, AT Products Department,
Industrial Products Division.
TEL: +81-463-24-8334
FAX: +81-463-24-8338
Polymer Engineering Center, Ecology and Energy
Laboratory
TEL: +81-463-24-8436
FAX: +81-463-24-9867

Photo 1

2

Appearance of back-chipping.

Furukawa Review, No. 22

2002