JP2002353180A - Cleaning method - Google Patents

Abstract

(57) [Problem] To provide a cleaning method capable of satisfactorily cleaning a rotating object in a cleaning container. SOLUTION: A cleaning container 1 to which a cleaning fluid in a supercritical state is supplied is provided, and a holder 9 accommodating an object to be cleaned 8 is provided in the cleaning container 1, and the holder 9 is rotatable and has a supercritical state. The cleaning fluid in the state passes through the holder 9. Side wall 4 of cleaning container 1
Baffle plate 15a that blocks the flow of the cleaning fluid
And 15b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning an object to be cleaned (a variety of mechanical parts, a silicon wafer, etc.) having a contaminant adhered to a surface thereof, using a cleaning fluid, particularly a supercritical cleaning fluid.

[0002]

2. Description of the Related Art In the manufacture of electronic parts, optical parts, precision machine parts, and the like, dust, oils and fats such as cutting oil and polishing oil, water, metal powder, ceramic particles, polymer chemistry, and the like adhered in the manufacturing process. A precision cleaning process for cleaning and removing contaminants such as substances is provided.

[0003] The cleaning method adopted in the conventional precision cleaning process is a dipping method in which pure water, a chemical solution or an organic solvent is used as a cleaning agent, and the object to be cleaned is immersed in the cleaning agent, and a combination of immersion and ultrasonic waves is used. And a steam cleaning method of cleaning with a vapor obtained by evaporating a cleaning agent.

However, in the cleaning method using a cleaning agent,
When cleaning an object to be cleaned having minute holes or grooves that are difficult for liquid to penetrate, or an object to be cleaned having a complicated shape, contaminants easily remain in the inside thereof, and it is difficult to obtain an excellent cleaning effect. . In the past, chlorofluorocarbon and trichloroethylene were often used as cleaning liquids, but these have become a major social problem in terms of environmental destruction such as destruction of the ozone layer, and their use is being abolished.

[0005] Under such circumstances, a cleaning method using a supercritical fluid such as carbon dioxide as a cleaning agent has recently been proposed. Supercritical fluids have a very high diffusion coefficient compared to liquids, have a very low viscosity, and can easily penetrate into fine pores and grooves, making them suitable for cleaning objects with complicated shapes. Because.

[0006] For example, a cleaning apparatus as shown in FIG. 10 is known. In FIG. 10A, a cylindrical container 31 is provided.
Has a top wall 32, a bottom wall 33, and a side wall 34, and a rotating shaft 37 is rotated by a magnetic clutch 36 driven by a motor 35, and a holder 39 holding an object to be cleaned 38 is attached to the rotating shaft 37. It rotates with the rotation shaft 37. The cleaning fluid is discharged from the supply port 40 immediately below the bottom wall 33 through the suction port 41 of the hollow rotary shaft 37 into the container from the discharge port 42, and the cleaning fluid after cleaning the object 38 is provided on the side wall 34. It is discharged out of the container from the discharged outlet 43.

[0007] In the cleaning apparatus in which the object to be cleaned rotates, the flow of the cleaning fluid is important. That is, in order to improve the cleaning effect, the holder 39 for holding the object 38
This is because the difference between the rotation speed of the cleaning fluid and the speed of the cleaning fluid greatly affects the cleaning effect. That is, when the relative speed of the holder 39 to the cleaning fluid in the container 31 is higher, the flow of the cleaning fluid is disturbed, and the cleaning fluid easily enters the concave portion on the surface of the object to be cleaned, and the cleaning effect is improved. However, in the apparatus shown in FIG. 10, since there is no object in the container 31 that disturbs the flow of the cleaning fluid, the cleaning fluid in the container 31 flows following the holder 39 at a speed slightly lower than the speed of the holder 39. . That is, since the cleaning fluid layer that flows in a laminar flow regularly is formed on the surface of the cleaning target 38, cleaning of the cleaning target 38 by the cleaning fluid becomes insufficient, and the cleaning cannot be performed well.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to clean a rotating object in a cleaning container well. To provide a cleaning method.

[0009]

In order to achieve the above-mentioned object, the present invention provides a cleaning container comprising:
The relative speed of the holder for holding the object to be cleaned with respect to the cleaning fluid is increased by rotating the object to be cleaned and performing cleaning while blocking the flow of the cleaning fluid with the baffle plate mounted in the cleaning container. Since the flow of the cleaning fluid is disturbed by the velocity gradient, sufficient contact between the cleaning fluid and the object to be cleaned is ensured, and the cleaning effect is improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the cleaning method of the present invention comprises:
In a method of cleaning an object to be cleaned by a cleaning fluid introduced into the cleaning container while rotating the object to be cleaned held by a holder in the cleaning container, a flow of the cleaning fluid is blocked by a baffle plate mounted in the cleaning container. It is characterized by washing while stopping.

In order to enhance the cleaning effect, the baffle is preferably mounted on at least one of the side walls, the bottom wall or the top wall of the cleaning vessel. In addition, the baffle plate is attached to the inner surface of the side wall of the cleaning container so as to be perpendicular to the rotation axis for rotating the object to be cleaned. This is more preferable because it can promptly supply, and can improve the overall cleaning ability.

According to the cleaning method of the present invention, the cleaning fluid that comes into contact with the baffle plate is blocked and, as shown in FIG. On the surface of the baffle plate 24, various speed gradients are formed as shown by examples 26 and 27, and the cleaning fluid is sufficiently mixed by the speed gradient that changes in a complicated manner, and dirt on the surface of the object to be cleaned is scraped out. Thus, it can be cleaned well. In the velocity gradients 26 and 27, the magnitude of the velocity U (x) at each portion along the inward direction (Y axis) of the washing container from the surface of the baffle plate 24 is zero on the surface of the baffle plate 24 and goes inward. And gradually increase. After reaching the maximum velocity Umax, the fluid in the inner part 28 is laminar and the fluid velocity is a constant value Umax. The speed change from zero speed to the maximum value Umax is steeper in the speed gradient 26 than in the speed gradient 27. That is,
The velocity gradient of the fluid in the turbulence 25 changes in a complicated manner on the surface of the baffle plate 24 in accordance with the uneven shape of the turbulence 25.

If the cleaning fluid is a supercritical fluid, it can be suitably used for cleaning ultra-precision electronic parts and optical parts.

Examples of the cleaning medium usable in the cleaning method of the present invention include fluids such as ethane, propane, butane, ammonia, nitrous oxide and carbon dioxide. It is preferable to use carbon dioxide as the cleaning medium from the viewpoint of safety for workers and the environment. If necessary, a cleaning aid (for example, an organic solvent such as IPA) can be added. The cleaning conditions using the cleaning medium as a supercritical fluid are not particularly limited as long as the pressure and the temperature are within a range for maintaining the supercritical state of each cleaning medium. When using carbon dioxide as the cleaning fluid, the pressure is preferably 30 to 4
The pressure is 0 MPa, and the temperature is preferably 60 to 120 ° C.

Examples of the object to be cleaned to which the cleaning method of the present invention can be suitably used include electronic parts, optical parts or precision machine parts, and porous parts made of glass, ceramic, synthetic resin or metal. Can be

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing one embodiment of a cleaning apparatus used in the cleaning method of the present invention. In FIG. 1A, a cylindrical container 1 includes a top wall 2, a bottom wall 3, and a side wall 4, and a rotating shaft 7 is rotated by a magnetic clutch 6 driven by a motor 5, so that an object to be cleaned 8 is appropriately cleaned. The holding tool 9 held and fixed by the pressing means is attached to the rotating shaft 7 and rotates together with the rotating shaft 7. The cleaning fluid is supplied to the supply port 1 directly below the bottom wall 3.
From 0 through the suction port 11 of the hollow rotary shaft 7, a large number of discharge ports 12 are discharged into the container, and the cleaning fluid after cleaning the object to be cleaned 8 is discharged out of the container through the discharge port 13 provided in the side wall 4. Is done.

Baffle plates 15a and 15b are vertically mounted on the inner side surface of the side wall 4 via a support 14. FIG. 1B is a cross-sectional view taken along the line AA in FIG. Note that support is not necessarily required to attach the baffle plate to the container, and the baffle plate may be directly attached to the inner wall surface of the container as shown in FIGS. 16 is a bearing.

According to the cleaning apparatus configured as described above, the cleaning fluid (for example, carbon dioxide) is compressed to a pressure equal to or higher than the critical pressure (preferably 30 to 40 MPa) by a compressor (not shown). The temperature is raised to a critical temperature or higher (preferably 60 to 120 ° C.) by a heater (not shown) on the downstream side of the machine to generate a supercritical carbon dioxide fluid, and the valve 17 is opened by opening the valve 17. 10, suction port 11 and discharge port 1
2, a supercritical carbon dioxide fluid is introduced into the cleaning vessel 1. Next, when the motor 5 is started to drive the magnetic clutch 6 and the rotating shaft 7 is rotated by the magnetic force of the magnetic clutch 6, the holder 9 is also rotated integrally with the rotating shaft 7. When the rotation speed of the motor 5 is gradually increased and the holder 9 is rotated at high speed, the supercritical carbon dioxide fluid discharged into the cleaning container 1 from the plurality of discharge ports 12 causes Sprayed evenly between. Since the baffle plates 15a and 15b are attached to the inner surface of the side wall 4 via the support 14, the flow of the cleaning fluid along the inner peripheral surface of the container is blocked, and the relative speed of the holder 9 with respect to the cleaning fluid is reduced. Becomes larger. Thus, the irregular velocity gradient of the cleaning fluid generated on the surfaces of the baffles 15a, 15b (U in FIG. 9).
Since the flow of the cleaning fluid is disturbed by (x), contaminants attached to the cleaning object 8 are removed in a scraping manner and dissolved in the supercritical carbon dioxide fluid. In particular, when the object to be cleaned 8 is a porous substance, the cleaning fluid easily enters the pores due to the disturbed flow, and the cleaning fluid is replaced smoothly, so that the cleaning effect is remarkable.

The washed supercritical carbon dioxide fluid is pushed radially outward from the center of the container 1 by the centrifugal force generated by the rotating holder 9, and the outlet 13 and the valve provided on the side wall 4 are provided. It is discharged out of the container through 18.

As described above, the irregular flow of the cleaning fluid generated by the baffle plate does not cause uneven cleaning,
Good cleaning can always be performed with a clean cleaning fluid.

FIG. 2 is a perspective view of the holder 9, 9a is a detachable support shaft, 9b is a shelf for mounting the object to be cleaned and holding and fixing the object to be cleaned by an appropriate pressing means. is there.

FIG. 3 shows another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 3A, the inner surfaces of the top wall 2 and the bottom wall 3 are obstructed respectively. Board 19,
20a and 20b are attached. FIG. 3B is a cross-sectional view taken along the line BB of FIG. 3A, and FIG.
It is CC sectional view taken on the line CC of FIG.

FIG. 4 shows still another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 4 (a), the inner surfaces of the top wall 2, the bottom wall 3 and the side wall 4 are provided. Are baffles 19, 20a and 20b and 21a and 2 respectively.
1b is attached. FIG. 4A is a side view including a cross section taken along line D-D of FIG. 4B, and FIG.
4 (c) is a sectional view taken along the line EE of FIG.
It is arrow sectional drawing.

FIG. 5 shows still another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 5 (a), the holder is composed of an upper holder 22a and a lower holder 22b.
Consisting of parts. On the inner side surface of the side wall 4, baffle plates 23a and 23b are protruded so as to be orthogonal to the rotation shaft 7. 5A is a side view including a cross section taken along the line GG of FIG. 5B, and FIG. 5B is a cross-sectional view taken along the line HH of FIG. 5A.

FIG. 6 shows still another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 6 (a), the holder is composed of an upper holder 22a and a lower holder 22b.
Consisting of parts. Baffle plates 23a and 23b project from the inner surface of the side wall 4 so as to be orthogonal to the rotating shaft 7. Further, the baffle plate 21
a and 21b are attached. FIG. 6B shows FIG.
FIG. 3A is a sectional view taken along the line II of FIG.

FIG. 7 shows still another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 7 (a), the holder is composed of an upper holder 22a and a lower holder 22b.
Consisting of parts. Baffle plates 19, 20a and 20b are attached to the inner surfaces of the top wall 2 and the bottom wall 3, respectively. Further, baffle plates 23a and 23b project from the inner surface of the side wall 4 so as to be orthogonal to the rotation shaft 7.
7A is a side view including a cross section taken along the line JJ of FIG. 7C, FIG. 7B is a cross-sectional view taken along the line KK of FIG.
7C is a cross-sectional view taken along the line LL of FIG. 7A, and FIG. 7D is a cross-sectional view taken along the line MM of FIG. 7A.

FIG. 8 shows still another embodiment of the cleaning apparatus used in the cleaning method of the present invention. As shown in FIG. 8 (a), the holder is an upper holder 22a and a lower holder 22b.
Consisting of parts. Baffle plates 19, 20a and 20b are attached to the inner surfaces of the top wall 2 and the bottom wall 3, respectively. Further, baffle plates 23a and 23b are provided on the inner side surface of the side wall 4 so as to be orthogonal to the rotation shaft 7,
Further, baffle plates 21a and 21b are attached to the inner side surface of the side wall 4 in a vertical direction. FIG. 8A shows FIG. 8C.
8B is a side view including a cross section taken along the line NN of FIG. 8, and FIG.
8A is a cross-sectional view taken along arrow PP, FIG. 8C is a cross-sectional view taken along arrow QQ in FIG. 8A, and FIG. 8D is a cross-sectional view taken along arrow RR in FIG. FIG.

[0028]

Since the present invention is constructed as described above, the object to be cleaned is held against the cleaning fluid by performing the cleaning while blocking the flow of the cleaning fluid with the baffle plate provided in the cleaning container. Since the relative speed of the holder to be cleaned increases and the flow of the cleaning fluid is disturbed, sufficient contact between the cleaning fluid and the object to be cleaned is secured, and the cleaning effect is improved.

In particular, the method according to claim 4 can be suitably used for cleaning ultra-precision electronic parts and optical parts.

[Brief description of the drawings]

FIG. 1 (a) is a side view including a cross section showing an embodiment of a cleaning apparatus used in the cleaning method of the present invention, and FIG. 1 (b) is a cross-sectional view taken along the line AA of FIG. 1 (a). It is.

FIG. 2 is a perspective view of one embodiment of a holder.

3 (a) is a side view including a cross section showing another embodiment of the cleaning apparatus used in the cleaning method of the present invention, and FIG. 3 (b) is a cross section taken along line BB of FIG. 3 (a). FIG. 3 (c) shows FIG.
It is CC sectional view taken on the line CC of (a).

4 shows a further embodiment of the cleaning apparatus of the present invention, FIG. 4 (a) is a side view including a cross section taken along line D-D of FIG. 4 (b), and FIG. 4 (b) is FIG. 4A is a sectional view taken along the line EE in FIG.
FIG. 4C is a sectional view taken along the line FF in FIG.

5 shows a further embodiment of the cleaning device of the present invention, FIG. 5 (a) is a side view including a cross section taken along line GG of FIG. 5 (b), and FIG. FIG. 6 is a sectional view taken along the line HH in FIG.

FIG. 6 (a) is a side view including a cross section showing a further embodiment of the cleaning apparatus of the present invention, and FIG. 6 (b) is FIG. 6 (a).
2 is a sectional view taken along the line II of FIG.

7A and 7B show still another embodiment of the cleaning apparatus of the present invention. FIG. 7A is a side view including a cross section taken along line JJ of FIG. 7C. 7 (a) is a sectional view taken along the line KK, FIG. 7 (c) is a sectional view taken along the line LL in FIG. 7 (a), and FIG. 7 (d) is a line MM in FIG. 7 (a). FIG.

8 shows a further embodiment of the cleaning apparatus of the present invention, FIG. 8 (a) is a side view including a cross section taken along the line NN of FIG. 8 (c), and FIG. 8 (a) is a cross-sectional view taken along arrow PP, FIG. 8 (c) is a cross-sectional view taken along arrow QQ in FIG. 8 (a), and FIG. 8 (d) is an RR arrow in FIG. 8 (a). FIG.

FIG. 9 is a diagram schematically showing a turbulent flow generated on the baffle plate surface and a velocity distribution of the cleaning fluid from the baffle plate surface to the inside.

FIG. 10A is a side view including a cross section of a conventional cleaning apparatus, and FIG. 10B is a plan view thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Washing container 2 ... Top wall 3 ... Bottom wall 4 ... Side wall 5 ... Motor 6 ... Magnetic clutch 7 ... Rotating shaft 8 ... Washed object 9,22a, 22b ... Holder 15a, 15b, 19,20a, 20b, 21a , 21
b, 23a, 23b, 24 ... baffle plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyuki Sora 2-274, Obatani-cho Kohata, Nishi-ku, Kobe-shi, Hyogo (72) Inventor Mamoru Miyagawa 7-13-21, Uozakiminami-cho, Higashinada-ku, Hyogo Kaoru Muraoka 1-16-10 Kokubo Akashi, Hyogo Prefecture Ansel Mo 502 Akashi 502 F-term (reference) 3B201 AA03 AA46 AB33 AB44 AB47 BB02 BB87 BB91

Claims (4)

[Claims] 1. A method for cleaning an object to be cleaned by a cleaning fluid introduced into the cleaning container while rotating the object to be cleaned held by a holder in the cleaning container, wherein the cleaning object is cleaned by a baffle plate attached to the cleaning container. A cleaning method characterized by performing cleaning while blocking a flow of a fluid. 2. The cleaning method according to claim 1, wherein the baffle is attached to at least one inner surface of a side wall, a bottom wall, or a top wall of the cleaning container. 3. A baffle plate is provided on an inner surface of a side wall of the cleaning container.
The cleaning method according to claim 1, wherein the cleaning method is mounted so as to be orthogonal to a rotation axis for rotating the object to be cleaned. 4. The cleaning fluid according to claim 1, wherein the cleaning fluid is a supercritical fluid.
4. The cleaning method according to 2 or 3.