JP2010264341A - Dust collecting apparatus and dust analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize manufacturing conditions and washing conditions by efficiently and surely removing dust stuck to the surface of a workpiece, by evaluating cleanliness of the workpiece with high sensitivity and high accuracy by collecting and analyzing the removed dust, and by applying the result to a washing process in a manufacturing site. <P>SOLUTION: Under a decompressed environment by a decompressing chamber 1, a gas or a mixture of a gas and a minute liquid is sprayed to the surface of a product 11 to separate and remove dust 12 stuck to the surface. Using a pump 10, the separated and removed dust 12 is collected on a dust collecting filter 8 and then, the dust 12 stuck to the dust collecting filter 8 is observed and analyzed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dust collecting apparatus and a dust analyzing method for peeling and removing minute dust adhering to various minute mechanical parts such as a magnetic disk device and a minute lens.

In recent years, many products such as semiconductors and magnetic disk devices have been miniaturized, and high cleanliness is also required in the cleaning process. Therefore, a method of quantitatively evaluating the cleanliness of the washed product is regarded as important.
When assessing cleanliness, observing the surface of the product directly is the most reliable method. However, there are various shapes and surface states of products, and there is no device for efficiently observing them. Even if a commercially available observation apparatus is used, it takes a very long time for evaluation, and it is difficult to apply it to the manufacturing site of the product.

  As described above, since it is difficult to directly evaluate the cleanliness of the product surface, an indirect method in which dust remaining on the product is once peeled off and recovered and observed is realistic. This is called the LPC method, and this method is generally used. The LPC method is a method in which a product is cleaned using an ultrasonic cleaning machine, and the number of dusts separated in pure water is measured with an in-liquid particle counter.

JP 2003-225625 A JP 2007-294938 A

  However, the LPC method is a partial measurement method that measures only about 2% of pure water. For this reason, it is difficult to detect dust for parts with high cleanliness, and there is a problem that the quantitativeness of the numerical value is questioned. Moreover, since it takes a long time to measure the total amount, it is not realistic and a new evaluation method is desired.

  As an elemental technique for the LPC method, a method of peeling dust on the product surface in air is known. As a typical method, there is an air blowing method in which high-pressure air is blown onto a product. Among the air blow methods, there is a method called an air knife method. As shown in FIG. 1, the air knife method is a method in which high-pressure air is blown from the nozzle 102 onto the surface of the product 101 in a line shape, and the separated dust 103 is sucked by the suction unit 104.

  The appearance of the air layer on the product surface is shown in FIG. This air layer is composed of a boundary layer formed on the outermost surface of the product due to the viscosity of air, and a transition layer and a turbulent layer on the boundary layer. The boundary layer is a region where the velocity of the fluid is lower than that of the turbulent layer or the transition layer due to the influence of viscosity. For this reason, even if air is blown, the airflow speed gradually decreases and it is difficult to reach the outermost surface of the product. In the air blow method or the air knife method, there is a problem that the boundary layer cannot be broken and the dust cannot be peeled off because the air does not reach the minute dust on the surface. In the air blow method or the air knife method, large dust of the order of several tens of μm (for example, 70 μm or more) can be peeled off, but it is difficult to remove dust of the order of several μm or less due to the influence of the above-described air viscosity.

  In order to break this boundary layer, an ultrasonic air method has also been proposed. In the ultrasonic air method, as shown in FIG. 3, high pressure air that is vibrated ultrasonically from the air discharge unit 112 is blown onto the surface of the product 111, and the dust 113 is vibrated and peeled off from the surface of the product 111. In this method, the suction unit 114 sucks 113. However, since the ultrasonic air method is effective only in the vicinity of the air discharge portion, it is an effective method mainly for a plane. Therefore, when the object has a complicated shape, there is a problem that it is difficult to remove dust deposited in the recess.

  In addition, the methods of Patent Documents 1 and 2 have been proposed. In patent document 1, while conveying the board | substrate or sheet | seat etc. which are to-be-cleaned objects, the air containing a positive ion is sprayed with respect to the one surface, the adhering dust or the contaminating fine particle is peeled off, and the surface where the said air was sprayed A dust removal method for neutralizing by neutralizing the water is disclosed. Patent Document 2 discloses a cleaning method in which a substance in the surface of a workpiece and the inside of a processing hole is removed by blowing a vortex air flow. However, even in the methods of Patent Documents 1 and 2, the boundary layer cannot be broken for the same reason as described above, and it is difficult to remove minute dust.

As described above, there is no dust collection method that can remove dust in the order of several μm in general in a dry environment, and there is no dust analysis method using this method. .
The present invention has been made in view of the above problems, and can efficiently and surely peel off dust adhering to the surface of the object, and collect and analyze the peeled off dust to clean the object. An object of the present invention is to provide a dust collection device and a dust analysis method that can optimize the manufacturing conditions and the cleaning conditions by applying to the cleaning process at the manufacturing site. .

  An aspect of the dust collecting apparatus includes a chamber, a holding mechanism that holds an object in the chamber, a nozzle that is provided in the chamber and blows a gas or a mixture of a gas and a liquid on the object, and the chamber. A first exhaust mechanism for connecting and exhausting the interior of the chamber; and a dust collecting filter connected to the chamber and collecting dust in the chamber.

  In one embodiment of the dust analysis method, an object is held in a holding mechanism in a chamber, the inside of the chamber is exhausted, and a gas or a mixture of gas and liquid is sprayed on the object by a nozzle provided in the chamber. The dust separated from the object is collected in a dust collection filter connected to the chamber, and the dust attached to the dust collection filter is analyzed.

  According to the above aspects, dust attached to the surface of an object can be efficiently and surely separated, and the cleanliness of the object is evaluated with high sensitivity and high accuracy by collecting and analyzing the separated dust. This makes it possible to optimize the manufacturing conditions and cleaning conditions when applied to the cleaning process at the manufacturing site.

It is a schematic diagram for demonstrating the air knife method. It is a schematic diagram which shows the mode of the air layer on the product surface. It is a schematic diagram for demonstrating the ultrasonic air method. It is a mimetic diagram showing a schematic structure of a dust collecting device by a 1st embodiment. It is a flowchart which shows the dust analysis method by 1st Embodiment in order of a step. It is a characteristic view which shows the result of having evaluated the wind pressure of the gas from the noise which reaches | attains a product. It is a schematic diagram which shows schematic structure of the dust collection apparatus by the modification 1 of 1st Embodiment. It is a schematic diagram which shows schematic structure of the dust collection apparatus by the modification 2 of 1st Embodiment. It is a schematic diagram which shows schematic structure of the dust collection apparatus by the modification 3 of 1st Embodiment. It is a schematic diagram which shows schematic structure of the dust collection apparatus by the modification 4 of 1st Embodiment. It is a characteristic view which shows the change of the wind pressure of the gas at the time of performing a pulse drive. It is a schematic diagram which shows schematic structure of the dust collection apparatus by 2nd Embodiment. It is a flowchart which shows the dust analysis method by 2nd Embodiment in order of a step. It is a schematic diagram which shows schematic structure of the dust collection apparatus by the modification of 2nd Embodiment.

  Hereinafter, specific embodiments will be described in detail with reference to the drawings.

(First embodiment)
First, the configuration of the dust collecting apparatus according to the first embodiment will be described.
FIG. 4 is a schematic diagram showing a schematic configuration of the dust collecting apparatus according to the first embodiment.

  In this dust collecting apparatus, 1 is a decompression chamber having an internal volume of about 5 L, for example. Reference numeral 2 denotes a holding mechanism that holds the product 11 as an object in the decompression chamber 1. Reference numeral 3 denotes a nozzle that is provided in the decompression chamber 1 and blows a predetermined gas (gas) on the surface of the product 11, for example, an inner diameter of about 4 mm. 4 is a valve that opens and closes to introduce gas into the nozzle 3. 5 is a filter for filtering the gas introduced into the nozzle 3, and is, for example, a hollow fiber filter having a filtration performance of about 0.1 μm. A first exhaust mechanism is configured by including the valve 6 and the pump 7. The valve 6 opens and closes the exhaust for vacuum sealing in the decompression chamber 1. The pump 7 is, for example, a diaphragm type exhaust pump. A dust collection filter 8 is connected to the decompression chamber 1 and collects dust 12 in the decompression chamber 1. A second exhaust mechanism is configured including the valve 9 and the pump 10. The valve 9 opens and closes to exhaust gas containing dust in the decompression chamber 1. The pump 10 is, for example, a diaphragm type exhaust pump. The dust collection filter 8 is a membrane filter having a hole diameter corresponding to the dust to be evaluated, and is provided between the decompression chamber 1 and the valve 9.

Next, a dust analysis method including a dust collection method according to the first embodiment will be described.
FIG. 5A is a flowchart showing the dust analysis method according to the first embodiment in the order of steps.

First, the product 11 is installed in the holding mechanism 2 in the decompression chamber 1 opened to atmospheric pressure (step S1).
Subsequently, the valve 4 is closed, the valve 6 is opened, and the pump 7 is operated to evacuate the decompression chamber 1 and decompress (step S2). After reducing the pressure to a predetermined pressure, for example, about 1 × 10 ² Pa, the valve 6 is closed and the pump 7 is stopped.

Subsequently, the valve 4 is opened, and gas is blown from the nozzle 3 to the surface of the product 11 (step S3).
The gas used is, for example, nitrogen gas, the pressure of the gas ejected from the nozzle 3 is about 0.1 MPa, and the gas flow rate is about 70 L / min. By introducing the gas for 5 to 6 seconds, the pressure in the decompression chamber 1 becomes atmospheric. Thereafter, the valve 4 is closed.

Subsequently, the valve 9 is opened, the pump 10 is operated, and the gas in the decompression chamber 1 is exhausted (step S4).
At this time, the exhausted gas contains the dust 12 adhering to the surface of the product 11 and is filtered by the dust collection filter 8 provided between the decompression chamber 1 and the valve 9. All dust 12 is collected. The gas filtration by the dust collection filter 8 can be performed in an extremely short time (a few orders of magnitude shorter than the case of liquid filtration) compared to the case of liquid filtration.
The dust collection method of this embodiment is comprised by said step S1-S4.

Subsequently, the dust collection filter 8 is removed, and the dust 12 attached to the dust collection filter 8 is observed and analyzed (step S5). After removing the dust collecting filter 8, the decompression chamber 1 leaks from the valve 6 to open the inside of the decompression chamber 1 to the atmosphere, and the product 11 is taken out.
The dust 12 adhering to the dust collection filter 8 is observed and analyzed using a predetermined evaluation system. As an evaluation system, for example, an optical microscope, an image pickup device such as a CCD, an image processing device or the like is used. Using an optical microscope and an imaging device, the dust collection filter 8 is automatically photographed by step and repeat. Using the image processing device, for example, a binarization process is performed on the captured image to divide image (pixel) information based on a predetermined threshold into binary values of 1 and 0, for example. Thereby, the dust is recognized and extracted, and the size and the number of dust are evaluated. Depending on the contents of the evaluation, in addition to the optical microscope, an evaluation using an electron microscope or an elemental analyzer can also be performed.

  In the present embodiment, considering that the evaluation criteria differ depending on the product to be evaluated and the dust, for example, as shown in FIG. 5B, the above steps S2 to S4 are repeated a predetermined number of times (steps). S6) may be used. After performing steps S2 to S4 a predetermined number of times, the above step S5 is executed. Thereby, reliable dust collection and evaluation according to a product and dust are attained.

Here, the pressure in the decompression chamber in the dust collection apparatus and the dust analysis method described above will be described.
In the present embodiment, the nozzle shape is selected and the gas flow rate is set so that the force applied per unit area of the product surface is basically increased. These conditions also depend on the size of the product. When the product is large, it is necessary to select each condition so that a corresponding gas spray area can be obtained.

One of the most important matters in this embodiment is the pressure in the decompression chamber. Basically, the effect of accelerating the separation of dust under a reduced pressure environment appears from a region slightly lowered from the atmospheric pressure, and can be clearly seen, for example, on the order of 10 ⁴ Pa.

FIG. 6 is a characteristic diagram showing the results of evaluating the wind pressure of the gas reaching the product surface.
Here, the relationship between the pressure in the decompression chamber and the gas wind pressure is shown in each case where the pressure of the gas ejected from the nozzle is 0.1 MPa, 0.2 MPa, and 0.3 MPa. According to the result of FIG. 6, just by reducing the pressure in the decompression chamber by one digit from the atmospheric pressure (about 10 ⁵ Pa), the wind pressure increases several times, and the effect can be clearly confirmed. Under the reduced pressure environment, the mean free path of gas molecules increases in inverse proportion to the pressure. Therefore, the collision probability between the gas molecules is small, and the speed of the gas molecules increases due to the pressure difference. There is a tendency for the wind pressure to saturate when the pressure in the decompression chamber is around 10 ³ Pa or less, but this is thought to be due to the fact that it is outside the viscous flow region and reaches an intermediate region where it is difficult to be affected by gas molecules. . As described above, it was confirmed that the wind pressure of the gas reaching the product surface is increased by the reduced pressure in the reduced pressure chamber.

As shown in FIG. 2, when gas flows on the surface of the object, a layer called a boundary layer that is generated by viscosity is formed. Although it depends on the conditions, it is considered that a boundary layer having a thickness of the order of 10 μm to several tens of μm is usually formed under atmospheric pressure. The thickness of the boundary layer changes depending on the viscous force of the gas, and tends to become thinner as the viscous force becomes smaller. Under a high pressure including atmospheric pressure, the viscous force is substantially constant, but in the region of 10 ² Pa or less, the viscous force decreases in proportion to the pressure. That is, under the pressure of 10 ² Pa or less, the thickness of the boundary layer is effectively reduced.

The above-mentioned consideration on the wind pressure shows a macro characteristic regarding the gas, and exhibits a sufficient effect even in a slight reduced pressure environment. In addition, the consideration regarding the influence of the boundary layer described later shows microscopic characteristics, and the effect appears at 10 ² Pa or less.
Therefore, the selection of the pressure condition in the decompression chamber depends on the size and specific gravity of the dust, the adhesion state, and the gas blowing conditions, but the decompression that exerts the maximum effect on the efficient dust removal on the product surface. The pressure in the chamber is 10 ² Pa or less.

In the present embodiment, utilizing the fact that the gas molecule density is diluted on the product surface in a reduced pressure environment as compared with the atmospheric state, the pressure in the reduced pressure chamber is set to 10 ² Pa or less, and gas is supplied from the nozzle to the product surface. Spray. Under a pressure of 10 ² Pa or less, the viscous force decreases in proportion to the pressure, so that the boundary layer is equivalently thinned, and the gas ejected from the nozzle can efficiently reach the product surface. For this reason, fine dust of, for example, several μm or less attached to the product surface is easily and reliably peeled off.

  Further, since the mean free path of gas molecules increases in inverse proportion to the pressure under a reduced pressure environment, the collision probability between the gas molecules is small, and the speed of the gas molecules increases due to the pressure difference. Therefore, the separation distance between the nozzle and the product surface can be secured large (for example, about several mm to several tens of mm), and even when the product surface has a complicated shape, sufficient peeling effect of dust attached to the product surface can be achieved. A high cleaning effect on the product surface can be achieved.

  As described above, according to the present embodiment, the dust 12 attached to the surface of the product 11 can be efficiently and surely separated, and the surface of the product 11 can be cleaned by collecting and analyzing the separated dust 12. It is possible to evaluate the degree of sensitivity with high sensitivity and high accuracy, and optimization of manufacturing conditions and cleaning conditions can be realized by applying to the cleaning process at the manufacturing site.

Hereinafter, various modifications of the present embodiment will be described.
In addition, in the dust collecting apparatus of various modifications, about the structural member similar to what was shown by FIG. 4, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

(Modification 1)
FIG. 7 is a schematic diagram illustrating a schematic configuration of the dust collecting apparatus according to the first modification of the first embodiment. In FIG. 7, the illustration of the valve 6 and the pump 7, the dust collection filter 8, the valve 9 and the pump 10 is omitted for convenience.
In this example, a plurality of (four in the illustrated example) products 11 are installed side by side in a holding mechanism 13 provided in place of the holding mechanism 2 in the decompression chamber 1. Corresponding to each product 11, a plurality of (four in the illustrated example) nozzles 14 are provided in place of the nozzles 3 in FIG. As in the first embodiment, with the inside of the decompression chamber 1 decompressed, the valve 4 is opened, and the gas filtered through the filter 5 is sprayed from the nozzles 14 onto the surface of each product 11 to adhere to the surface. Remove dust.

  In the manufacturing site, a plurality of products 11 may be processed as one batch, and how many dusts remain in one batch may be used as an evaluation index. This embodiment corresponds to such a case. Of course, when the opening of the nozzle 14 is large with respect to the dimension of the product 11, the number of nozzles can be reduced with respect to the number of products. On the other hand, when evaluating a large product, a plurality of nozzles 14 can be arranged for one product 11. In this example, the filter 5 and the valve 4 are provided on one pipe, and the plurality of nozzles 14 are arranged by branching on the downstream side. However, the present invention is not limited to this configuration. For example, a filter and a valve can be arranged for each of a plurality of branched nozzles. It is also possible to form each nozzle completely independent of the gas supply source.

(Modification 2)
FIG. 8 is a schematic diagram illustrating a schematic configuration of the dust collecting apparatus according to the second modification of the first embodiment. In FIG. 8, the filter 5, the valve 6 and the pump 7, the dust collection filter 8, the valve 9 and the pump 10 are omitted for convenience.
In this example, the holding mechanism 2 is provided with a rotation mechanism 15 for the product 11. The rotation mechanism 15 is a stage mechanism that can change the direction of the product 11 with respect to the nozzle 3 in the direction of the arrow shown in the figure. The effective thickness of the boundary layer can be changed by changing the surface of the product 11 with respect to the gas blowing direction by the rotation mechanism 15. In addition, this is particularly effective for products whose surface is not flat. In this example, the case where only the mechanism that can freely rotate in one direction is incorporated in the holding mechanism 2 as the rotating mechanism 15 is shown. However, a rotating mechanism in a plurality of directions, an XY stage mechanism, etc. Various movable mechanisms can be incorporated depending on the purpose.

(Modification 3)
FIG. 9 is a schematic diagram illustrating a schematic configuration of a dust collecting apparatus according to Modification 3 of the first embodiment. In FIG. 9, the filter 5, the valve 6 and the pump 7, the dust collection filter 8, the valve 9 and the pump 10 are omitted for convenience.
In this example, the holding mechanism 2 is provided with a vibrator 16 that is a vibration mechanism of the product 11, and a discharge needle 17 that is a gas static elimination mechanism is provided in the nozzle 3.

  The vibrator 16 vibrates the product 11 installed in the holding mechanism 2. The vibrator 16 is provided with a signal generator (not shown) for controlling the vibration, and the vibrator 16 can generate vibration from a low frequency region to an ultrahigh frequency (ultrasonic wave) region. Further, instead of or in addition to generating continuous vibration in the vibrator 16, for example, impact vibration using a pulse signal in which one pulse is on the order of several ms is generated in the vibrator 16, and the product 11 of the dust 12. Desorption from the surface can also be promoted.

  The discharge needle 17 is a so-called ionizer. By incorporating the discharge needle 17 into the nozzle 3, the charge balance of the gas sprayed on the product 11 is neutralized to remove static electricity. Thereby, detachment | desorption from the surface of the product 11 of the dust 12 is accelerated | stimulated. An AC high-voltage power supply (not shown) connected to the discharge needle 17 is provided outside the decompression chamber 1, and the discharge needle 17 is driven by a high-frequency AC method.

In this example, although the case where both the vibration excitation mechanism and the static elimination mechanism are provided is illustrated, only one of them may be provided.
Further, as a method for promoting the detachment of the dust 12 from the surface of the product 11, it is also effective to heat the product 11 by providing a halogen lamp or the like in the decompression chamber 1.

(Modification 4)
FIG. 10 is a schematic diagram illustrating a schematic configuration of a dust collecting apparatus according to Modification 4 of the first embodiment. In FIG. 10, the illustration of the valve 6 and the pump 7, the dust collection filter 8, the valve 9 and the pump 10 is omitted for convenience.
In the present example, a pulse driving unit 18 that pulse-drives gas ejection from the nozzle 3 is provided. A pulse drive unit 18 is connected to the valve 4 and pulse-drives opening and closing of the valve 4. Thereby, detachment | desorption from the surface of the product 11 of the dust 12 is accelerated | stimulated.

FIG. 11 is a characteristic diagram showing changes in the wind pressure of the gas that reaches the product surface when pulse driving is performed.
Here, the result when the valve 4 is pulse-driven five times per second is illustrated. At the moment when the valve 4 is opened, the pressure of the gas ejected from the nozzle tends to overshoot. In this example, by utilizing this characteristic, a gas wind pressure about twice the gas wind pressure in a steady state is instantaneously obtained. Therefore, a high peeling effect of the dust 12 from the surface of the product 11 can be obtained without changing the pressure of the gas ejected from the nozzle 3.

In addition, the above-described modified examples 1 to 4 can also be configured by selecting two or more modified examples from these and combining them appropriately.
Specifically, the following embodiments can be adopted.

As a modified example 1 + 2, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2, a plurality of nozzles 14 in place of the nozzle 3, and a rotating mechanism 15.
As a modified example 1 + 3, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2 and a plurality of nozzles 14 in place of the nozzle 3, and a vibrator 16 serving as an excitation mechanism, and One or both of the discharge needles 17 serving as a static elimination mechanism are provided.
As a modified example 1 + 4, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2, a plurality of nozzles 14 in place of the nozzle 3, and a pulse driving unit 18.
As a modified example 2 + 3, the dust collecting apparatus of FIG. 4 is provided with a rotation mechanism 15 and one or both of a vibrator 16 as an excitation mechanism and a discharge needle 17 as a charge removal mechanism.
As a modified example 2 + 4, a rotation mechanism 15 and a pulse driving unit 18 are provided in the dust collecting apparatus of FIG.
As a modified example 3 + 4, the dust collecting apparatus of FIG. 4 is provided with one or both of the vibrator 16 as the vibration mechanism and the discharge needle 17 as the static elimination mechanism, and the pulse driving unit 18.
As a modified example 1 + 2 + 3, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2, a plurality of nozzles 14 in place of the nozzle 3, a rotation mechanism 15, and an excitation mechanism. One or both of the vibrator 16 and the discharge needle 17 which is a static elimination mechanism are provided.
As a modified example 1 + 2 + 4, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2, a plurality of nozzles 14 in place of the nozzle 3, a rotation mechanism 15, and a pulse driving unit. 18 is provided.
As a modified example 1 + 3 + 4, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2 and a plurality of nozzles 14 in place of the nozzle 3. One or both of the discharge needles 17 that are mechanisms are provided, and a pulse driving unit 18 is provided.
As a modified example 2 + 3 + 4, the dust collecting apparatus of FIG. 4 is provided with a rotation mechanism 15, one or both of a vibrator 16 as an excitation mechanism and a discharge needle 17 as a static elimination mechanism, and a pulse driving unit 18.
As a modified example 1 + 2 + 3 + 4, the dust collecting apparatus of FIG. 4 is provided with a holding mechanism 13 provided in place of the holding mechanism 2, a plurality of nozzles 14 in place of the nozzle 3, a rotation mechanism 15, and a vibration mechanism. One or both of the vibrator 16 and the discharge needle 17 which is a static elimination mechanism are provided, and the pulse driving unit 18 is provided.

(Second Embodiment)
Next, a second embodiment will be described. In the present embodiment, a dust collecting device is configured in substantially the same manner as in the first embodiment described above, and dust collecting and dust analysis are performed in substantially the same manner, but the first is that a small amount of liquid is contained in the gas ejected from the nozzle. This is different from the first embodiment.
In addition, in the dust collecting apparatus of this embodiment, about the structural member similar to what was shown by FIG. 4, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

FIG. 12 is a schematic diagram showing a schematic configuration of the dust collecting apparatus according to the second embodiment.
In addition to the apparatus configuration of FIG. 4 of the first embodiment, this dust collecting apparatus includes a nozzle 21 for introducing liquid into the nozzle 3 and a valve 22 for opening and closing for introducing liquid into the nozzle 21. I have. By opening the valve 22 together with the valve 4, the liquid is introduced into the nozzle 21, and a gas (hereinafter referred to as a mixture) containing the liquid is ejected from the nozzle 4 and installed in the holding mechanism 2 in the decompression chamber 1. The mixture is sprayed on the surface of the product 11.

Next, a dust analysis method including a dust collection method according to the second embodiment will be described.
FIG. 13A is a flowchart showing the dust analysis method according to the second embodiment in order of steps.

First, steps S11 and S12 similar to steps S1 and S2 in FIG.
Subsequently, both the valve 4 and the valve 22 are opened, and the mixture is sprayed from the nozzle 3 onto the surface of the product 11 (step S13).
The gas used for the mixture is, for example, nitrogen gas, the pressure of the gas ejected from the nozzle 3 is about 0.1 MPa, and the gas flow rate is about 70 L / min. The liquid used for the mixture is, for example, pure water, and pure water is introduced at a rate of about 0.1 cc with respect to the flow rate of 1 L of nitrogen gas. In the case of pure water, when the ratio exceeds 1% of the mixture, the liquid does not volatilize and accumulates in the dust collecting filter 8 and the dust collecting ability is significantly reduced. Accordingly, the pure water content of the mixture is preferably 1% or less, and more preferably 0.5% or less. Even if the pure water content is 0.1%, the effect of removing the dust 12 on the surface of the product 11 is increased. The specific resistance of pure water is preferably 1 MΩ · cm or less. When ultrapure water is used, it is desirable to adjust the specific resistance by adding CO ₂ gas or the like to nitrogen gas. Thereby, charging of ultrapure water can be prevented.

  As the liquid used for the mixture, it is also effective to use alcohol such as isopropyl alcohol or ethyl alcohol instead of pure water. These have boiling points of about 82 ° C. and about 78 ° C., respectively, which are lower than water and high in volatility. Therefore, it is more advantageous when mixing with gas than with pure water. In addition to these liquids, liquids having higher volatility or lower boiling points than water may be used.

When the mixture is introduced for 5 to 6 seconds, the pressure in the decompression chamber 1 becomes an atmospheric state. Thereafter, both the valve 4 and the valve 22 are closed.
Thereafter, steps S14 and S15 similar to steps S4 and S5 in FIG.

  In the present embodiment, in the same manner as in the first embodiment, considering that the evaluation criteria differ depending on the product to be evaluated and the dust, for example, as shown in FIG. S14 may be repeated a predetermined number of times (step S16). After performing steps S12 to S14 a predetermined number of times, the above step S15 is executed. Thereby, reliable dust collection and evaluation according to a product and dust are attained.

In this embodiment, when gas is sprayed at a high spray pressure, a small amount of liquid contained in the mixture is struck against the surface of the product 11 while being dispersed. Since liquid particles having a mass larger than that of gas molecules collide with the surface of the product 11, the ability to repel dust 12 adhering to the surface is several times larger than that of gas molecules, and the ability to peel off dust 12 is greatly increased. To increase.
Moreover, the liquid is easily vaporized after colliding with the surface of the product 11 by making the content of the liquid gas into a minute amount that is easy to vaporize or using a liquid that easily volatilizes such as alcohol. Therefore, no liquid remains in the decompression chamber 1, and the vacuum exhaust of the decompression chamber 1 and the recovery of the separated dust 12 are not affected.

  As described above, according to the present embodiment, the dust 12 adhering to the surface of the product 11 can be more efficiently and surely removed, and the separated dust 12 is collected and analyzed, so that the surface of the product 11 is recovered. It becomes possible to evaluate the cleanliness with high sensitivity and high accuracy, and optimization of manufacturing conditions and cleaning conditions is realized by applying to the cleaning process at the manufacturing site.

(Modification)
Hereinafter, modifications of the present embodiment will be described.
Note that in the dust collecting apparatus of the modification, the same components as those shown in FIG.

  FIG. 14 is a schematic diagram illustrating a schematic configuration of a dust collecting apparatus according to a modification of the second embodiment. In FIG. 14, for the sake of convenience, the state in the decompression chamber 1 (holding mechanism 2 and the like), nozzle 3 and valve 4, filter 5, nozzle 21 and valve 22, valve 6 and pump 7, dust collection filter 8, valve 9 and pump 10 are shown. Illustration is omitted.

  In this example, a heater 23 which is a heating mechanism is provided between the decompression chamber 1 and the dust collection filter 8. When the mixture is sprayed on the surface of the product 11 to remove dust from the surface, the liquid vaporized in the mixture may be liquefied again in the vacuum chamber 1. In this example, by heating the inside of the decompression chamber 1 using the heater 23, vaporization of the liquid in the mixture can be promoted, and condensation can also be prevented.

Note that Modifications 1 to 4 of the first embodiment can also be applied to the configuration of FIG. 13 of the present embodiment or the configuration of FIG. 14 of the modification.
In addition, the first to fourth modifications of the first embodiment are appropriately combined by selecting two or more modifications from these, and the configuration of FIG. 13 of the present embodiment or the configuration of FIG. 14 of the modification is used. Each can also be applied.

  Hereinafter, various aspects will be collectively described as additional notes.

(Appendix 1) a chamber;
A holding mechanism for holding an object in the chamber;
A nozzle provided in the chamber and spraying a gas or a mixture of gas and liquid on the object;
A first exhaust mechanism connected to the chamber and exhausting the chamber;
A dust collecting device comprising: a dust collecting filter connected to the chamber and collecting dust in the chamber.
(Supplementary note 2) Further comprising a second exhaust mechanism connected to the chamber and exhausting the inside of the chamber,
The dust collecting apparatus according to claim 1, wherein the dust collecting filter is provided between the chamber and the second exhaust mechanism.
(Additional remark 3) The said gas is nitrogen gas, The dust collection apparatus of Additional remark 1 or 2 characterized by the above-mentioned.
(Appendix 4) The dust collecting apparatus according to any one of appendices 1 to 3, wherein the liquid is water, a liquid having higher volatility than water, or a liquid having a lower boiling point than water.
(Additional remark 5) The said holding | maintenance mechanism has a movable mechanism which makes the direction of the said target object with respect to the said nozzle variable, The dust collection apparatus of any one of Additional remarks 1-4 characterized by the above-mentioned.
(Appendix 6) The dust collecting apparatus according to any one of appendices (1) to (5), wherein the holding mechanism includes an excitation mechanism that vibrates the object.
(Supplementary note 7) The dust collecting apparatus according to any one of supplementary notes 1 to 6, further comprising a static elimination mechanism that removes static electricity from the gas or the mixture.
(Supplementary note 8) The dust collecting apparatus according to any one of supplementary notes 1 to 7, further comprising a heating mechanism between the chamber and the filter.
(Supplementary note 9) The dust collecting apparatus according to any one of supplementary notes 1 to 8, further comprising a drive mechanism that pulse-drives ejection of the gas or the mixture from the nozzle.
(Appendix 10) Hold the object in the holding mechanism in the chamber,
Evacuating the chamber;
The nozzle provided in the chamber sprays a gas or a mixture of gas and liquid onto the object,
Dust separated from the object is collected in a dust collecting filter connected to the chamber,
Analyzing the dust adhering to the dust collection filter;

  According to the present case, dust attached to the surface of the object can be efficiently and reliably peeled off, and by collecting and analyzing the peeled dust, the cleanliness of the object can be evaluated with high sensitivity and high accuracy. It is possible to optimize the manufacturing conditions and cleaning conditions by applying it to the cleaning process at the manufacturing site.

DESCRIPTION OF SYMBOLS 1 Pressure reduction chambers 2, 13 Holding mechanism 3, 14, 21 Nozzle 4, 6, 9, 22 Valve 5 Filter 7, 10 Pump 8 Dust collection filter 11 Product 12 Dust 15 Rotating mechanism 16 Vibrator 17 Discharge needle 18 Pulse drive part 23 Heater

Claims (6)

A chamber;
A holding mechanism for holding an object in the chamber;
A nozzle provided in the chamber and spraying a gas or a mixture of gas and liquid on the object;
A first exhaust mechanism connected to the chamber and exhausting the chamber;
A dust collecting device comprising: a dust collecting filter connected to the chamber and collecting dust in the chamber. A second exhaust mechanism connected to the chamber and exhausting the interior of the chamber;
The dust collection device according to claim 1, wherein the dust collection filter is provided between the chamber and the second exhaust mechanism.   The dust collecting apparatus according to claim 1, wherein the holding mechanism includes an excitation mechanism that vibrates the object.   The dust collecting apparatus according to claim 1, further comprising a static elimination mechanism that removes static electricity from the gas or the mixture.   The dust collecting apparatus according to any one of claims 1 to 4, further comprising a drive mechanism that pulse-drives ejection of the gas or the mixture from the nozzle. Hold the object in the holding mechanism in the chamber,
Evacuating the chamber;
The nozzle provided in the chamber sprays a gas or a mixture of gas and liquid onto the object,
Dust separated from the object is collected in a dust collecting filter connected to the chamber,
Analyzing the dust adhering to the dust collection filter;

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