JP2833939B2 - Pedestal for falling dust measurement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedestal for measuring dust falling, and more particularly to a structure of a pedestal for measuring dust falling in a space having high cleanliness such as a clean room for manufacturing semiconductors and a gap inside the apparatus.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the cleanliness of a clean room, a method of measuring the degree of cleanliness in which a semiconductor wafer is left in a clean room for a certain period of time and the difference in the number of adhering dusts before and after the standing is calculated as falling dust has been used. I have. The conventional pedestal for measuring falling dust on which a semiconductor wafer is mounted for performing this measurement has a substantially quadrangular flat plate shape with an arc-shaped corner as shown by 5 in the top view of FIG. The dust measurement wafer 3 was placed.

[0003]

The above-described conventional pedestal for measuring dust falling is not provided with any countermeasures against static electricity such as using a conductive material. When the wafer is in a charged state, dust with a small particle size, which needs to be measured in order to control the cleanliness required in a clean room, is attracted to the wafer by static electricity and adheres to it, so that accurate measurement values are obtained. It is difficult. Further, depending on the size of the pedestal, the pedestal does not enter when installed in a narrow place, so that the space required for measurement is limited. In addition, since the wafer is flat, there is a problem that the wafer may slide off the pedestal.

[0004]

The pedestal for measuring dust falling according to the present invention takes measures against static electricity by coating the surface of the pedestal with a conductive substance. Further, the outer shape of the pedestal is adjusted to the size of the wafer for measuring dust falling, and a stopper for preventing the wafer for measuring dust falling from sliding down is provided around the outer shape.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a top view of an embodiment of a dust falling measurement pedestal according to the present invention.

The present embodiment comprises a pedestal body 1 and a stopper 2 for preventing slip-down, each of which is made of polyvinyl chloride coated with a conductive substance, and a pedestal for measuring dust falling and a wafer 3 for measuring falling dust. To prevent charging. This allows
The measurement value obtained by the dust fall measurement is about 1/10 of the measured value when the dust fall measurement wafer is charged at 1 KV, and a more accurate value can be obtained.

Further, the pedestal has an approximately octagonal shape and the size is adjusted to the size of the dustfall measurement wafer, so that an occupied area is about as compared with the conventional dustfall measurement pedestal shown in FIG. This is one third, and it is possible to install the device even in a narrow place such as a gap between the devices. Further, stoppers 2 for preventing slipping are provided at equal intervals on the four sides of the pedestal to prevent the falling wafer 3 for dust measurement from slipping.

Another embodiment of the present invention is shown in the top view of FIG. The pedestal main body 4 has a substantially triangular shape, and has a slip-off prevention device 2 at the outer end. As a countermeasure against static electricity, a thin metal wire is stuck on the surface of the pedestal body 4 and the stopper 2 for preventing slip-down. The stoppers 2 for preventing slip-down may not be at equal intervals as long as the respective intervals are shorter than the diameter of the wafer for measuring dust falling.

[0009]

As described above, the present invention eliminates dust adhesion due to static electricity and enables measurement in a narrow place.
There is an effect that the wafer for measuring the falling dust can be reliably mounted.

[Brief description of the drawings]

FIG. 1 is a top view of one embodiment of the present invention.

FIG. 2 is a top view of another embodiment of the present invention.

FIG. 3 is a top view of an example of a conventional pedestal for measuring dust falling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pedestal main body 2 Stopper for prevention of sliding down 3 Wafer for dust fall measurement 4 Pedestal main body 5 Pedestal

Claims (2)

(57) [Claims] 1. A pedestal for measuring a falling dust used for measuring a falling dust in a clean room on which a semiconductor wafer is placed,
A pedestal for measuring falling dust, wherein the pedestal surface is coated with a conductive material. 2. The pedestal for measuring falling dust according to claim 1, wherein an outer shape of the pedestal is adjusted to the size of the wafer, and a stopper for preventing the wafer from sliding down is provided around the pedestal.