DISCO Technical Review Aug. 2018

Investigation of particles in the dicing saw usage environment
Sales Engineering dept.
Abstract
Particle measurement was performed in the area surrounding the dicing saw installed inside the class10000 clean room on the normal floor. Eight points in the front, back, left, and right of the machine weremeasured three times at heights of 30 to 100 cm. The particle measurement results for both dicing saws
met the criteria. No significant increases in particles were observed in areas where increases in particles
were expected to occur. It may be able to operate as a class 10000 clean room even on the normal floor if
managed appropriately.

1. Introduction

However, in Japan, a country subject toIn the past, the level of cleanliness required ofearthquakes, there have been cases in the pastclean rooms used in the semiconductor assembly

where grated flooring has become dislodged andprocess was not high in comparison to the level ofthe equipment has fallen over during an

cleanliness required in front-end processes.

earthquake because the optimal grated flooring

However, with advances in devices and thinner

was not selected and the optimal methods towafers in recent years, there are cases of using

secure the equipment were not performed,

clean room environments and structures that meet

resulting in injury, a large amount of downtime,

front-end process standards for the thinning andand costly expenses for repairs and restoration.

singulation processes that are directly after theBecause the standard level of cleanliness in thefront-end process, and even some cases of grated

assembly process is Class 10,000 (Class 7 in ISO

flooring(1) being adopted to increase the laminarstandards, see Fig. 2), even normal flooring isflow and reduce the number of particles.

thought to be able to sufficiently achieve a levelof environment that does not affect the process.
In this study, we measured the number ofparticles that are generated in a Class 10,000
clean room in which dicing saws (hereinafter“dicers”) operate and which adopts normalflooring.

Fig. 1. Grated flooring

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DISCO Technical Review Aug. 2018

Fig. 2. Clean room category

2-3． Measuring Method

2. Method of Experiment
The particles in the dicer operating

Measurements were performed for a duration

environment were measured using the methodof one minute using an airborne particle

described below.

counter. Each point was measured three times
at intervals of one minute.

2-1. Measuring Environment

A total of eight points were measured: points

The measurements were performed in a Class

approx. 10 cm from the front, back, left, and10,000 clean room environment used in aright of the dicers at heights of 30 cm and 100

package assembly factory in Japan. The flooring

cm. Refer to Fig. 4 for details. At eachconsisted of both grated flooring and normal

measurement point, a particle size of 0.5 µm orflooring, and there was a down-flow of clean air

higher was measured at a conversion volume ofthrough ceiling filters. The normal flooring in

28.3 L, in accordance with ISO 14644-1(3). The

the clean room is cleaned once a day with anmeasurements were performed while the dicers

adhesive roller and a dry mop.

where being used in fully-automatic operation.

2-2. Equipment
More than ten 300 mm fully-automatic dicers
are installed on the normal flooring. Two of thedicers were selected for this experiment. The
positions of the measured dicers are shown in
Fig. 3.

Fig. 3. Placement of measuring equipment

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DISCO Technical Review Aug. 2018

4. Discussion
The level of cleanliness with the dicers inoperation was within the criteria of a Class
10,000 clean room.
Based on the results of this experiment, we haveconfirmed that if appropriate cleaning is being
performed, there is no extreme increase in theamount of particles in a Class 10,000 level

Fig. 4. Places measured on equipment

environment, even if the dicers are installed on
normal flooring. Regarding point B (processing
3. Measurement Resultssection), where it was easy for particles to be

The total number of particles in each set ofgenerated, because there were no large quantities

three measurements are shown in Fig. 5. Aof particles indicated for either dicer 1 or dicer 2,quantity of 30,000 particles or lower can be said

we have clarified that it would be effective toto meet the criteria of Class 10,000. For bothinstall a duct which forces the particles from thedicer 1 and dicer 2, the accumulative quantity ofprocessing section toward the exhaust port.

particles for three measurements was less thanThe reason we think that the quantity of

30,000 in all of the locations. A large amount ofparticles measured at point A was high is because

particles were observed at point A (front ofpoint A is next to the aisle where many people

equipment) at a height of 100 cm for bothpass through, and also because it is on the front

dicers. In particular, point B (processing section

side of the equipment, which is where the user

where dicing is performed) had a particularly

operates the equipment. We also think thathigh amount of particles for both dicers.

Fig. 5. Total of three measurements around dicers on normal flooring

3DISCO Technical Review Aug. 2018verifying the dependability according tochanges over time and the type of equipment
shall further clarify whether it is possible to use
normal flooring.

References(1) “SEMI and SEAJ Collection of Examples ofIndividual Accidents: Guidance in Practical
Application”, August 21, 2018
http://www.seaj.or.jp/publication/safety/tebiki.pdf(2) Shiro Hara 2006, “The World of Local Clean
Environments”, Industrial Research Committee(3) ISO 14644-1:2015

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Appendix
The area around the UV irradiation equipment
and inspection equipment installed on the grated
flooring in the same clean room was measured
as a reference. Please refer to Fig. 6.
There are other various factors in addition to theflooring composition that are suspected to havegenerated the particles.

Fig. 6. Total of three measurements around equipment on grated

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