JP2890263B2 - Cleaning method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cleaning method by spraying a liquid.

[Conventional technology]

Originally, there are a shower type and a spray type for washing by a water spray type. As shown in FIG. 28, the shower type discharges water pressurized to ² to 5 kg / cm ² from a hole (341) of a perforated pipe (340) and drops by gravity.
This is a method in which the water droplet of H) is applied to the object to be cleaned (W ₂₀ ) to perform cleaning. The spray type is 15 to 30 kg as shown in Fig. 29
/ cm ² of the pressurized water hit toward the nozzle 150mm to the cleaning object spaced of 250mm ejection i.e. high velocity Kirishizuku the (SP) by (351A~351E) (W ₂₁₎ This is a cleaning method. Needless to say, the latter has a greater cleaning effect.

However, in the above-described conventional water (liquid) washing method, liquid is continuously sprayed onto the surface of the object to be cleaned. That is, the surface to be cleaned is immersed in water. Also in the spray type, their Kirishizuku collect in the cleaning object (W ₂₂₎ on a surface, agglomerated, become liquid layer as seen in FIG. 30 (Ld), to cover the said surface It becomes. Therefore, foreign matter (Zk,
…) Will be buried under the water and spray (S
The droplets sprayed at a high speed by P) or the like, i.e., liquid fine particles, once hit the liquid surface, and as shown in FIG. 31, the speed is reduced, and after passing through the liquid layer with the excess, the target foreign matter is removed. (Zk), so that the force is considerably reduced and the force for peeling off the foreign matter is also reduced.

Another cause is that the velocity of the sprayed liquid fine particles is reduced. That is, the fine particles sprayed on the liquid layer surface are decelerated before hitting the surface to be cleaned. This will be described with reference to FIG.

In the first place, the behavior of the flow after the liquid spray fine particles hit the surface of the object to be cleaned is complicated as shown in FIG. Generally, the spray flow (SP) ejected from the nozzle (371) has a conical shape. That is, when viewed in cross section, the particles are divergent, and the fine particles (Pl, Pm, Pn, Po outward from the center) that hit each part on the cleaning surface are reflected at each reflection angle and bounce off ( Pl ′, Pm ′, Pn ′, P
o '). They are also used for the subsequent projecting fine particles (Pq, P
r, Ps). Then, each of these fine particles changes its direction again and creates another flow. As a whole, as shown in the figure, the flow (SPcr) entrains the surrounding air to become an airflow, and flows outward as a layer (SPcrl) having a certain thickness. And these layers of flow (SPcrl)
Subsequent sprayed fine particles will strike. Here, the airflow layer (SPcrl) acts as a so-called cushion, and the projected fine particles are rebounded or decelerated even after passing through the layer (SPcrl), and are decelerated on the cleaning surface, that is, when they hit foreign matter. The impact force is considerably reduced.

For the above two reasons, it has been found that the cleaning effect is not sufficiently improved only by continuously spraying the liquid.

In recent years, with the rapid development of high technology, perfect cleaning, especially for printed wiring boards, has become a problem. On the same substrate, cutting or drilling during the manufacturing process, chips generated by grooving, or electrolytic substances, electrolytic solutions, residues of processing liquids such as acids and alkalis, especially adheres They are often stuck to recesses and holes, corners of wiring copper foil, and the like. If these are not completely removed, defective soldering, short-circuiting of electric current, defective electrical insulation, etc. may occur during assembly, which may cause serious problems after assembly.

In particular, recently, there has been an increasing tendency to increase the density of the substrate, to reduce the distance between wirings, and to reduce the diameter of through-holes (through-holes). It has become. That is, the conventional cleaning method cannot meet these requirements.

Here, the cleaning effect of the spray method, which is said to be the most effective among the conventional cleaning methods, will be considered.

As described above, in the spray method, the foreign matter is removed by the impact force of the weakened fine particles, and the removing ability is reduced. However, there is still a problem in this removing action. This will be described with reference to the drawings. No.
FIG. 33 is a perspective view of a conventional spray-type cleaning system, and FIG. 34 is a cross-sectional view taken along line “Q”-“Q” in FIG. First, the nozzle (381 b) from pressurized cleaning liquid to be washed (W ₂₄₎ aiming at to be sprayed. The spray droplets or fine particles strike the substrate surface, and cause the foreign substances adhering to the substrate surface to be separated from the substrate surface by the collision force. Next, a large number of fine particles from the subsequent spray gather,
That is, they are aggregated and become liquid. Then, it spreads on the surface of the substrate (W ₂₄ ) and becomes a liquid layer (Ll), which has a thickness of several mm, and is pushed outward by the coagulated water by the subsequent spray and flows outward of the substrate. In addition, the flow includes only the separated foreign matter and flows out of the substrate (W ₂₄ ). Since the substrate is moved in the direction of the arrow ( "F _3"), it is the same as foreign matter on the subsequent substrate surface is being removed or cleaned.

The state in which the foreign matter is removed will be described in more detail step by step. See also FIG. 34, which is a sectional view. The substrate (W ₂₄ ) moves in the “F ₃ ” direction, that is, from right to left in FIG. Since the cleaning action at each moving position is different, these will be described step by step.

First stage: FIG. 34 and an enlarged view of a portion "H" in FIG. 34A
See figure. W ₂₄ is a substrate, Wa is a blind hole or groove, Wb is a through hole, and Wc is a wiring copper foil. This figure shows the processing liquid before spraying, the processing liquid such as an acid solution or an alkaline solution, the electrolytic solution, the residue of the electrolyte (Zl, Zm, Zn,...) Adhere to the substrate. ing.

Second stage: FIG. 34 is an enlarged view of a portion "I" in FIG. 34, see FIG. 35B.
By spraying the cleaning liquid, the fine particles of the cleaning liquid strike the substrate surface, and simultaneously strike residues (hereinafter collectively referred to as foreign matter including cutting powder) attached to the plate surface.
In this case, a spray (SP ₁ b) flow foreign material facing in a direction (SPr) of (Zl, Zm, Zn, Zp , Zq) , with its impact forces are peeled from the substrate (W ₂₄₎ surface, in May be flipped in the air or may move sideways. In addition, foreign matter (Zo, Zr) adhering to the shadow of the corner of the through hole (Wb) or copper foil (Wc) is not directly hit because it is behind the spray flow (SPr). It is still attached.

Third stage: FIG. 34 is an enlarged view of the "J" part in FIG. 34, see FIG. 35C.
The fine particles of the cleaning liquid are aggregated by the subsequent spray, and the liquid becomes a liquid layer (Ll) and covers the surface of the substrate (W ₂₄ ). Then, the fine particles of the spray flow (SPv) are first separated into the liquid layer (Ll)
In this case, since the direct impact force on the foreign objects (Zo, Zr) is reduced, the chance of the foreign objects being separated is reduced.

Fourth stage: Refer to FIG. 35D, which is an enlarged view of the "K" portion in FIG.
The liquid layer (Ll ′) on the substrate (W ₂₄ ) surface becomes thicker and the direct impact force of the spray flow (SPl) further decreases, so that the foreign matter (Zo,
Zr) becomes increasingly difficult to peel off and adheres as it is.

Fifth stage: See FIG. 35E, which is an enlarged view of the "L" part in FIG.
The collision of the spray liquid is over, and although the liquid layer (Ll ") has become slightly thinner, the foreign matter (Zo, Zr) remains as it is.

Sixth step: Even if the cleaning liquid in the liquid layer is removed or dried, the foreign matter is not removed and adheres (see FIG. 35F).
That is, the cleaning was not performed perfectly.

[Problem to be solved]

As described above, the liquid layer formed on the surface of the object to be cleaned by spraying the liquid covers foreign substances adhering to the surface and protects the liquid particles from the subsequent high-speed liquid particles of the spray. This makes it difficult to remove and remove foreign matter.

In addition, in the conventional spray type cleaning method, in particular, foreign matter adhering to the inner surface such as a fine uneven part, for example, a concave groove on a printed wiring board surface, a corner of a copper foil, and a through hole, It was difficult to remove completely.

An object of the present invention is to provide a conventional spray cleaning method,
By applying gas blowing and changing the spraying method, the foreign substances adhering to the hard-to-remove places as described above are completely removed, that is, completely washed.

[Means for solving the problem]

The gist of the present invention is that, after a liquid is once sprayed on a surface to be cleaned, the liquid layer is blown off by blowing a gas against foreign substances which still adhere to the surface and are further covered by the liquid layer. In this method, the exposed foreign matter is repelled by being hit with liquid fine particles in the next spraying, and is removed or washed.

A problem in the above method is the assignment between the liquid spray time and the gas spray time. In this method, it is divided into the following three types.

A. First method The liquid spray is continuously performed for a certain time, and immediately thereafter, the gas is continuously blown.

B. Second Method The liquid spray is performed intermittently (pulsed) for a certain period of time, and immediately thereafter, the gas is continuously or intermittently (pulsed) blown.

C. The third method A liquid spray is applied intermittently (pulse-like) to a certain surface of the object to be cleaned for a certain period of time, and at the same time, a gas is continuously or intermittently applied to the same surface between the intermittent liquids. (Pulse).

 Next, each method will be described in detail.

(1) First Method In this method, first, liquid spraying is performed for a certain surface of an object to be cleaned for a certain time, and then gas spraying is performed individually. The flow system which is frequently used will be described as an example. Please refer to FIG. First, an opening / closing gun for liquid (3) and an opening / closing gun for gas (13) are provided.
The former is connected to a liquid tank (9) via a pump (8) and the like, and the latter is connected to a gas accumulator tank (17). From these guns (3 and 13), one or more liquid airless spray nozzles (1; 1A; 1B,...) And gas nozzles (11; 11A, 11B,.
..), And these nozzles are alternately arranged for liquid and gas and arranged in series above the object to be cleaned (W). The operating parts of the two types of guns (3, 13) are connected to solenoid valves (5, 5) by operating air pipes (4, 14), respectively.
15) to the operating air tanks (16), and their solenoids are connected by switches (1
0,12).

Next, the operation of the above block diagram will be described. The object to be cleaned (W) placed on the disk conveyor (19) is "F"
It moves in the direction. Then, the liquid is first subjected to continuous spraying (“Ls”) to perform primary cleaning. The object to be cleaned, to which foreign matter that has not yet been removed by the cleaning, moves further and is continuously sprayed with gas ("Gs"), and the liquid sprayed on the surface of the object to be cleaned is sprayed with the liquid. The liquid layer or pool is blown off (FIG. 2), and the liquid is removed, that is, in a semi-dry state, and foreign matter (see FIG. 30) embedded in the lower portion of the liquid layer is exposed (FIG. 12). See). The adhered objects to be cleaned subsequently move, again receive a continuous spray of liquid, and are secondarily subjected to direct hits of liquid fine particles. Those which are not yet removed are those in which the tertiary and quaternary liquids and gases are sprayed, i.e., the cleaning and the residual liquid removal are repeated, thereby performing more perfect cleaning.

In the above description, the nozzles are fixedly arranged in a single-row series, but they may be arranged in a double-row series according to the area of the object to be cleaned.

Further, as shown in FIG. 3, the ejector of the liquid (21) in the middle, the moving direction of the ejector gas on both sides of straight line (31A, 31B) of the object to be cleaned as a group (W ₁₎ ( F ₁ ) is provided on a base (24) that slides at right angles to the base, and the base is alternately slid in the left and right directions (T ₁ , T ₂ ),
Each of the ejectors traverses on the moving object (W ₁ ). In this case, one of the gases is always jetted to the front of the jetting course of the cleaning liquid, so that it functions as a so-called defrosting. Therefore, as described above, the cleaning effect by the ejection of the liquid is greater. In this case, the trajectory of the ejection pattern has a zigzag shape (Lc) as shown in FIG. In the above description, one gas ejector (31A, 31B) is installed on each side of one liquid ejector (21), but the number of these ejectors depends on the area of the object to be cleaned. It may be increased accordingly.

There is another method as shown in FIG. Wash ejector liquid (41) and a gas jetting device (51) and the slide base (46) mounted one by one by traversing in a direction perpendicular to the moving direction of the cleaning object (W ₂₎ That is.
Also in this case, it is necessary to cause the liquid ejector (41) to precede and the gas ejector (51) to follow, and as shown in FIG.
As shown in FIG. 6 and FIG. 6B, it is necessary to invert those ejectors. As a result, after the liquid is hit, the liquid is always blown off by spraying the gas, and then the next liquid is hit, so that the cleaning effect can be improved as described above.

It should be noted that a gas ejector that blows in an air knife shape from obliquely above the object to be cleaned can be used to flush the liquid film on the object to be cleaned in one direction.

Here, as for the pump (8) in FIG. 1, it is not always necessary to pressurize the cleaning liquid. For example, if an ejector type is used, the pump becomes unnecessary. However, in order to increase the collision force on the object to be cleaned,
It is desirable to use a pump (gear pump, plunger pump, etc.) for pressurizing the cleaning liquid.

(2) Second method In this method, first, liquid spraying is performed intermittently (pulsedly) on a certain surface of an object to be cleaned, and then gas is continuously or intermittently (pulsedly) sprayed. It is done in. See FIG. In this block diagram, the difference from the first method in the above figure is that the spraying of the liquid and gas is intermittent (pulsed). Therefore, those guns (63, 73) and nozzles (61, 73)
Or and 61A, 61B, ..., 71, or and 71A, 71B, ...) are for intermittent (pulse) use, and their guns (63, 7
3) Operate each solenoid valve (65,75)
Is electrically connected to a pulse controller or timer (70). Note that, for simplification of the structure, the gas may be continuously blown. The rest is almost the same as FIG. 1 in the first method, and the description is omitted.

Before describing the operation of the present method, the operation of the intermittent spray will be described. What is intermittent ejection from the nozzle?
FIG. 8 shows the graph, which can be easily obtained by opening and closing a valve directly connected to the nozzle. In addition, the above-mentioned intermittent is generally constant,
As shown in FIG. 11, it is often used at a relatively high cycle, and rather pulsed ejection or spraying is more appropriate.

As described above, the intermittent ejection is performed by a liquid (cleaning liquid) and a gas (generally air). First, the cleaning action by the pulse spray of the cleaning liquid will be described. First, 9A
See the figure. The figure from the nozzle (61), in which the behavior of the flow when intermittently ejected to spray pattern (SPp) was hit to the object to be cleaned (W ₄₎ on the surface were illustrations of.

The figure shows the moment when the head of the first wave (SPpa) of the pulse spray reaches the surface of the moving object to be cleaned (W ₄ ). Originally, the shape of each of these spray patterns is spherical, and FIG. Following the arrival at the center of the top, ie, the spray pattern (SPpa), the spray pattern (SPpa) reaches the outer periphery in a continuous manner (FIG. 9B). After the hitting of the central part, the arc-shaped sides are still hitting (FIG. 9C), and when these ends, the hitting of the first wave spray pattern (SPpa), that is, the cleaning action by them ends. It is.

Now, the cleaning action of the spray pattern (SPpa) of the first wave will be described.

First stage: See section "B" in FIG. 9A and its enlarged view in FIG. 10A. Washload is a printed circuit board (W _4). The board enters the “F ₂ ” direction, that is, the spray area. In the “B” part in FIG. 9A, the spray (SPp) has not yet been received. Therefore, foreign matter adheres to each part on the substrate (W ₄ ). As an example, it is assumed that a concave portion (Wa), a through hole (Wb), a wiring copper foil (Wc), and the like are provided on the substrate (W ₄ ). It is assumed that foreign substances (Za, Zb,..., Zh) are attached to these parts and the surface of the substrate (W ₄ ).

2nd stage ..... Enlarged view of section "C" in FIG. 9B
As shown in FIG. B, each part on the substrate (W ₄ ) is directly hit by the fine particles of the cleaning liquid. That is, fine particles (Pa) are foreign matter (Za)
And jump off from the substrate (W ₄ ) surface (Z
a ') The other fine particles (Pb) hit directly in the same manner
b) and the other fine particles (Pc, Pd, Pe, ...) repel each foreign matter (Zc, Ze, Zf, ...) (Zc ', Ze', Zf ',
…). However, in the spray direction, the foreign matter (Zd, Zh) adhered behind the concave and convex portions (Wb and Wc) is adhered as it is, avoiding the direct hit.

In the hitting of the above spray pattern (SPpa), the gas flow (SPcr) due to the reflection action in the collision of the fine particles is slightly generated as in the conventional case described above, but the thickness of the intermittent spray pattern (SPpa) is small. Is relatively thin, the thickness of the airflow layer (SPcrl) is small, and it does not give a cushioning effect to the following fine particles unlike the conventional case, so that there is almost no problem. Therefore, the speed of the subsequent fine particles is rarely reduced, and the fine particles can hit the foreign matter with a required impact force and can be removed from the surface of the substrate (W ₄ ).

However, as also seen in the figure, a substrate (W ₄₎ uneven portion on the surface (Wb, Wc) in a spray direction foreign matter adhered to the portion that is behind the (SPr) (Zd, Zh ) Is attached without being hit directly.

Third stage: See FIG. 9B and FIG. 10C, which is an enlarged view of a portion "D" in FIG. 9B. By spraying the first wave in the second stage, the surface of the substrate (W ₄ ) received a small amount of mist and a relatively thin liquid layer (Lf) was generated. However, since these are very thin as compared with conventional ones, foreign substances on the substrate (W ₄ ) surface can be removed by the subsequent high-speed fine particles that are not decelerated as described above.

Further, as described in the second step, the foreign matter (Za ", Zb",..., Zg ") which has been repelled into the air falls again on the surface of the substrate (W ₄ ) to form a liquid layer. Although they go down, they do not directly adhere to the substrate (W ₄ ) due to the liquid layer (Lf),
It flows away with the flow of the liquid layer.

However, the foreign matter (Zd, Zh) that was behind the uneven portion described in the second stage is still attached.

Fourth stage: See FIG. 9C and an enlarged view of the "E" part in FIG. With the movement of the substrate (W ₄ ) in the “F ₂ ” direction, the spray projection direction is reversed (SPl) from the case of the second stage (SPr). Then, the foreign particles (Zd, Zh) adhered to the shadow at the above stage directly hit the fine particles during spraying. And it flies off.

Fifth stage: See FIG. 9C and an enlarged view of the “G” portion in FIG. 10E. In each of the above steps, not only the foreign substances adhering to the substrate (W ₄ ) surface but also all the foreign substances adhering to the uneven portions can be removed. However, the liquid film aggregated by spraying still covers the surface of the substrate, but since these are relatively thin, compared to conventional continuous spray cleaning,
The effect of removing foreign substances is far more effective.

The above describes the cleaning action of the intermittent spray first wave spray pattern (SPpa) in FIG. 9A,
The following second wave spray pattern (SPpb), third wave spray pattern (SPPC), the substrate ... by a similar action (W ₄₎
Wash on the surface. However, although it depends on the ratio between the spray time in these intermittent sprays and the break time, the spray time increases and the thickness of the liquid film formed on the substrate surface also increases. However, when the thickness is less than half of the conventional thickness (1 mm or less), a phenomenon of a remarkable decrease in the foreign substance removing action unlike the conventional case is not observed.

The time distribution of the above-mentioned intermittent spray is various depending on the washing conditions, and several examples are shown in FIG.
In addition, the effective use range is in the range of 1 c / s to 200 c / s as the cycle.

As described above, when the intermittent spray is sprayed on a relatively lightweight thin plate such as a printed wiring board, the board vibrates up and down in resonance with the intermittent motion. This vibration also contributes to the automatic exfoliation of the foreign matter adhering to the substrate. This is a secondary effect, but it can be said to be significant.

The energy applied to the substrate by applying the vibration to the substrate depends on the kinetic energy of the fine particles in the intermittent spray. And its kinetic energy depends on the velocity of the sprayed particles. Therefore, the speed needs to be high to some extent. At the current experimental stage, it is set to 20 m / sec or more. The speed depends on the diameter of the nozzle hole, the ejection pressure, and the distance from the nozzle to the surface of the object to be cleaned. Although it cannot be said unconditionally, the effect is improved in experiments when the distance is 75 mm or less.

Various washing liquids such as nonionic surfactants (glycerin, polyethylene glycol, etc.) are used depending on the purpose, but water is generally most suitable.

As described above, by intermittently spraying the cleaning liquid, the cleaning effect of removing foreign substances can be improved, and the cleaning liquid used can be 50% or less, and sometimes 5%, as compared with the conventional continuous spray. is there. This is also worth mentioning as a derivative effect.

As described above, it has been experimentally demonstrated that the cleaning effect of the intermittent spray of the liquid is greater than that of the continuous spray. But there are still things that are not perfect. That is, as described above, intermittently sprayed droplets of liquid accumulate and agglomerate on the surface to be cleaned, leaving a liquid film or puddle in a much thinner layer than in continuous spraying. Is inevitable (Lf in FIG. 10C and Lf ′ in FIG. 10D). As described above, the presence of these liquid films or the like reduces the speed of the fine particles of the liquid sprayed and projected, reduces the force for repelling foreign substances, and also reduces the cleaning power. That is, during intermittent spraying, it is desirable that these remaining liquid films and the like do not exist.

Therefore, the gist of the second method is that the above-described intermittent spray of the liquid is performed for a certain time, and then the gas is continuously or intermittently sprayed, so that the intermittent spray of the liquid remains on the surface to be cleaned. A liquid film or the like is also blown off, and in a state where it is not present, high-speed fine particles by intermittent spraying of a liquid are directly struck against foreign matter, and the foreign matter is repelled to effectively remove and clean.

FIG. 7 shows an example of a block diagram of the liquid and the gas as described above. Although there are many combinations or arrangement orders, the figure shows a block diagram based on a typical cleaning method in which intermittent sprays of liquid and gas are alternately arranged. The description of the block diagram has been described above, and will not be repeated.

Next, the operation of the above block diagram will be described. The object to be cleaned (W ₄ ) placed on the disk conveyor (79) is “F”
It moves in the direction. The liquid is first subjected to an intermittent spray (“Lsp”) to perform primary cleaning. The details of the operation of the cleaning are as described above, and thus description thereof is omitted. Then move further to intermittent spray of gas (“Gs
p "), the liquid (liquid film or liquid pool) adhering to the surface of the object to be cleaned is blown off by the intermittent spraying of the liquid, and the liquid is removed to be in a semi-dry state. The details of the operation are the same as those described above, and the description thereof will not be repeated, and the object to be cleaned is subsequently moved, again subjected to the intermittent spray of the liquid and subjected to the secondary cleaning, and then again subjected to the intermittent spray of the gas. The next liquid is removed, and if necessary,
The cleaning and the liquid removal are repeated in the order of tertiary, quaternary,.

The latter is more preferable for the timer or the pulse controller. This is because the setting of the cycle (1 c / s to 200 c / s) in milliseconds, that is, the pulse signal can be freely and easily selected.

(3) Third method In the second method, the intermittent ejection of liquid or gas is performed by:
Although each of them is performed separately, in the present method, the intermittent timing is related. That is, a method in which a liquid is intermittently sprayed on a surface of an object to be cleaned, and a gas is continuously or intermittently sprayed between the intervals.

The method will be described with reference to the drawings. See FIG. Intermittent spraying from liquid nozzle (81) (Ls
p) and intermittent spraying from the gas nozzle (91) (Gs
p) and the surface to be cleaned (W ₆ )
5)) and in reaching those wave phases,
They change the phase so that they do not overlap with each other. That is, immediately after a certain wave of liquid is hit, a gas wave is blown to blow off the liquid to make it a non-liquid state. Immediately after that, the next intermittent liquid wave is hit and the surface in the non-liquid state is made. This is to directly peel off and remove the upper foreign matter.

The setting of the intermittent ejection having a correlation between the liquid and the gas can be easily obtained by setting the pulse controller (90). The timings are variously set, and the main ones are shown in FIG.

I. During the suspension time (T) of the liquid spray (Lsp),
Gas blowing (Gsp) is performed for a certain time (T ₁ ) (see the “g” column in the figure).

B. Gas is blown before (t ₁ ) and after (t ₂ ) the liquid spraying time (t) (see the “h” column in the figure).

C. Gas blowing starts at the same time as the liquid blowing time, and the gas blowing is slightly longer than that of the liquid (t ₃ )
(See the "i" column in the figure).

D. Gas blowing is started slightly before the liquid blowing stops (t ₄ ), and the gas blowing ends slightly after the next liquid blowing stops (t _s ) (“j” in the figure). Column).

E. Gas blowing is started slightly before the liquid blowing stops (t ₆ ), and the gas is blown until a little after the start of the next liquid blowing (see the “k” column in the figure).

F. The spraying of the liquid is intermittent, and the spraying of the gas is continuous (see the column "l" in the figure).

The above is an example of the main timing, and other various settings can be made.

As described above, by adjusting the timing of spraying the liquid and the gas and hitting the surface to be cleaned (W ₆ ), the cleaning can be performed with a more compact apparatus than the first and second methods. It is.

Above, we have explained the micro uneven surface,
The cleaning effect is great not only for macro unevenness but also for flat surfaces. This is because, as described above, according to each method of the present invention, the residual liquid on the surface to be cleaned, which is generated by the liquid spray, is removed by the gas spray,
This is because the direct hit rate of the liquid spray on the foreign matter on the surface to be cleaned can be increased.

An example of experimental data based on the apparatus of the third method will be described below.

Experimental example (1) Object to be cleaned Glass epoxy wiring board (with copper plated through holes on both sides) a. Board size 350mm x 500mm b. Board thickness 1.6mm c. Through hole size 0.3 ~ 1.0mmφ (2) Cleaning water Water (3) Substrate transfer speed 2.0m / min (4) Pump used Plunger pump (5) Liquid nozzle Airless spray nozzle (6) Gas nozzle Air gun nozzle (7) Distance between nozzle and object to be cleaned 30mm (8) ) Injection timing of liquid and gas (A. above) Cycle 20c / s Opening time of liquid valve 30ms Opening time of gas valve 15ms (Refer to "g" column in Fig. 16.) The substrate that passed once was observed with a microscope.

Result: A plurality of foreign substances were found in the through-holes before washing, and none of them were found after washing. It was confirmed that the inside of the through hole having a small diameter of 0.3 mmφ was completely and quickly cleaned.

〔Example〕

First Embodiment In each method of the specific invention, a so-called airless spray method in which pressurized liquid is sprayed from a nozzle. However, the present invention is also applicable to two-fluid spray, that is, air spray. The advantages of the air spray are that the equipment cost is reduced due to the simplification of the apparatus, and that the liquid on the surface to be cleaned is quickly removed because the gas is also blown while the liquid is being blown. is there.

Second Embodiment In the first and second methods of the specific invention, the arrangement order of the spraying of the liquid and the gas is alternately performed in a series. Something like See FIG. However, it is assumed that Ls: spraying of liquid, Las: spraying of different liquids other than the above, Gs: spraying of gas, and these are all arranged in a series.

(1) Ls, Ls, Gs, Ls, Ls, Gs, ... ("d" column in Fig. 13) (2) Ls, Las, Gs, Ls, Las, Gs, ... ("d" column in the same diagram) (3) Ls, Gs, Las, Gs, Ls, Gs, Las, Gs, ... ("e" in the above figure)
(4) Ls, Gs, Gs, Ls, Gs, Gs, Ls, Gs, Gs, ... ("f" in the above figure)
(5) Ls, Gs, Gs, Las, Gs, Gs, Ls, Gs, Gs, Las, Gs, Gs, etc. ("f" column in the same figure) Other various combinations can be performed.

Third Embodiment In the third method of the specified invention, the liquid gun nozzle and the gas gun nozzle are different from each other. However, in the present embodiment, an integrated unit, that is, an airless spray nozzle with auxiliary air is used. As shown in FIG. 17, the airless spray nozzle with auxiliary air is one in which an auxiliary air nozzle (121) is attached to the tip of a conventional airless spray nozzle (111).

Originally, the airless spray nozzle does not use air. However, in order to change a spray pattern ejected from the airless spray nozzle, an air nozzle may be attached to the tip of the airless spray nozzle to perform spraying. In this embodiment, the airless spray nozzle with auxiliary air is used in the present invention. However, the auxiliary air nozzle is slightly different from the conventional one. Since the conventional one is for changing the shape of the spray pattern to be ejected as described above, for example, in order to narrow the width of the fan-shaped spray pattern, air is ejected from both sides through two air ejection holes. Because it was
It was general that a plurality of these ejection holes were provided. However, in the present invention, the spray pattern of liquid and gas is the same, not to change the spray pattern, but merely to give a time difference to the time of spraying. It is desirable that an air ejection hole be provided concentrically around the hole around the hole. An example of the structure is shown. Explaining this, the airless spray gun is provided with an open / close valve (114) and an air piston (118) for operating the same. A liquid inlet (115), which is pressurized by a liquid pump and flows in, is provided on a liquid flow path (116) to the opening / closing valve (114). Outlet (11
7) is provided. That is, an on-off valve is provided on the liquid circulation circuit, and the liquid is constantly circulating under a constant pressure regardless of whether the on-off valve is opened or closed. At the downstream part of the outflow path of the on-off valve (114), a spray outlet (123) for necessary liquid is provided.
A concentric circular air ejection hole (124) is provided in the outer periphery of 3). That is, the liquid and the gas are sprayed concentrically and in a conical shape with their timing adjusted. However, the ejection timing of the liquid and the gas is operated by separate solenoid valves.

Next, a block diagram of the present invention employing the airless spray gun nozzle with the auxiliary air is shown in FIG. The block diagram will be described. One or more airless spray guns with auxiliary air (110, 110A, 110B,...) Are arranged in series. For simplicity of description, a system in the case of one of them will be described. The airless spray nozzle (11
A liquid supply pipe (144) is connected to the upper liquid inlet (115) by a pipe, which branches off from the liquid supply pipe (143) (1).
44) It was done. Also, a return pipe (145) thereof is provided. The air cylinder (128) for operating the open / close valve (114) inside the nozzle (111) has a piston (11
8) An inflow port (119) for operating air for operation is provided, and a pipe (132) to the inflow port (119) is connected to a solenoid valve (135) as a collecting pipe (131). The valve is electrically connected to the operating air tank (137), and its solenoid is connected to the pulse controller (140). In the above description, the case of one airless spray gun with auxiliary air (110) has been described. However, when a plurality of gun nozzles of the same type are added to form a plurality, the respective liquid supply pipes (144;
A, 144B,…) and the collecting pipe (143) to connect to the liquid supply system.
In addition, except that each pipe (132; 132A, 132B,...) Of the auxiliary air is connected to the collecting pipe (131) and led to the solenoid valve (135), description thereof is omitted.

The timing at which the liquid and gas are ejected from the airless spray gun nozzle with the auxiliary air can be performed in the same manner as described in the third method (FIG. 16). Although the operation and effect are almost the same, the present embodiment is characterized in that the device is more compact because the liquid and gas gun nozzles are integrated.

Fourth Embodiment There are many types of cleaning liquids of the specific invention, such as water and soluble solutions (alcohol, benzene, etc.), but all of them are simple liquids. However, in this embodiment, the suspension is used as a washing liquid. The reason will be described. originally,
The cleaning action of the liquid spray is such that high-speed liquid particles in the spray collide with foreign matter adhering to the surface of the object to be cleaned, and the foreign matter is repelled by the collision force. However, if the collision force is weak, it cannot be done. You only need to increase the speed of the particles, but there are limits. In that case, the mass of the fine particles is increased, that is, the liquid fine particles may be made into solid fine particles having a larger mass.For that purpose, a suspension containing the solid fine particles may be used as a washing liquid. It is good. It is said that clogging of nozzle holes is likely to occur when a suspension is used.However, clogging also occurs because intermittent jetting increases the initial pressure for each intermittent operation more than in the continuous type. Work can be continued.

Fifth Embodiment In the description of the second and third methods of the specific invention, the object to be cleaned resonates and vibrates due to intermittent spraying, and they also contribute to the detachment of foreign matter as a secondary effect. Said. However, when the resonance occurs as described above, the resonance is difficult in the case of a lightweight thin plate such as a printed wiring board, and in the case of a thicker plate having a larger weight.
Therefore, it is desirable to separately apply vibration from outside. That is, in the present embodiment, the object to be cleaned is vibrated by a separate vibration device during the spraying of the liquid.

An example is shown in FIG. The conveyor shown in the figure shows the case of a multi-disc roller (203a,...). The diaphragm (204) is attached to the common bearing plate (202) of the multi-disk controller (203a, 203b,..., 203e) group in the range of the pulse spray pattern (SPp ₂ ). The disk rollers are vibrated all at once. The object to be cleaned (W ₁₀ ) passing over the disk controller group resonates to promote the cleaning effect.

When wire mesh (Km) is used as the conveyor,
As shown in FIG. 20, a back-up perforated plate (216) is provided on the lower surface of the wire mesh (Km), and a vibrating plate (214) is applied to the lower surface thereof to vibrate them. Vibration is given to the cleaning object (W ₁₁ ).

Sixth Embodiment In each of the above-described embodiments, the liquid is sprayed, that is, atomized, and the fine particles are hit against foreign substances adhering to the surface of the object to be cleaned, and the particles are peeled off. In this embodiment, however, the liquid is discharged from the extrusion gun nozzles (232, 231) at a high speed in a linear (bead) form without spraying the liquid as shown in FIG. , It is intensively hit on the surface of the object to be cleaned, i.e., spot-like, to repel foreign matter, and immediately thereafter, the liquid remaining in the same portion is blown off by intermittent or continuous gas blowing, Without weakening the linear ejection force of the liquid than the subsequent extrusion,
It is to remove and remove, that is, clean by hitting a foreign matter.

Fig. 22 shows a liquid extrusion nozzle (241)
FIG. 9 is a block diagram showing a method of alternately arranging a nozzle and a gas blowing nozzle (251) on a series for cleaning. Regarding the operation of the block diagram, the intermittent spraying of the liquid and the intermittent spraying of the gas in the second method of the specific invention described above are merely replaced by the liquid extrusion nozzle and the gas spraying nozzle in this example. Therefore, the description is omitted. Further, the combination of the arrangement order of the intermittent spraying of the liquid and the gas is as described in the second embodiment.
As in the embodiment, various combinations (FIG. 13) can be applied as needed.

Seventh Embodiment In the above-described FIG. 6 embodiment, the liquid extrusion nozzles and the gas blowing nozzles are alternately arranged in series, but in the present embodiment, the In place of the nozzles for gas and gas, an extrusion nozzle for liquid and a nozzle for spraying gas are juxtaposed, and these are sprayed above the object to be cleaned (FIG. 23) and sprayed by these two types of nozzles. The extension line in the direction is provided so as to be concentrated at one point on the object to be cleaned (W ₁₅ ) (FIG. 24). If necessary, a plurality of combinations of these two types of nozzles are arranged in a series.

The operation of this embodiment is the same as that of the third method except that the intermittent spray for liquid and gas is replaced by intermittent spray for liquid and intermittent spraying for gas, and a description thereof will be omitted. The timing of spraying the liquid and gas is the same as that in the third method (FIG. 16), so refer to the method.

Eighth Embodiment A liquid slit nozzle is used in place of the liquid extrusion nozzle in the seventh embodiment, and a gas blowing slit nozzle is used in place of the gas blowing nozzle. The liquid slit nozzle is 25th
As shown in the figure, a liquid is discharged in a film form and intermittently at a high speed, and the liquid is hit on the surface to be cleaned (W ₁₇ ) to clean the surface at once. Immediately after the above-mentioned striking, as shown in FIG. 26, gas is sprayed intermittently or continuously to blow off the residue of the struck liquid and weaken the force of the subsequent striking of the liquid film. By hitting the foreign matter without repeating and repeating these alternately, the foreign matter adhering to the surface of the object to be cleaned is removed, that is, washed.

Ninth Embodiment As shown in FIG. 27, the liquid slit nozzle and the gas blowing slit nozzle in the eighth embodiment are brought close to each other in parallel, and both are arranged above the object to be cleaned (W ₁₈ ). Further, the extension lines in the spraying direction are provided so as to substantially intersect on the surface of the object to be cleaned (W ₁₈ ) (FIG. 27). To explain the action, the cleaning action by hitting the film intermittently discharged at a high speed,
With the action of blowing off the liquid material remaining on the surface to be cleaned (W ₁₈ ) with gas at the same position during the intermittent intervals, without weakening the force of the subsequent intermittently hitting film, The cleaning is performed effectively. By repeatedly arranging the combination of these two types of nozzles in a series with respect to the moving direction of the object to be cleaned, the cleaning effect can be further enhanced.

The timing of spraying the liquid and gas is also
The method described in the third method is applied, so the method is referred to.

〔effect〕

In the conventional water-washing type cleaning method, only water or another liquid is applied to the surface of the object to be cleaned for cleaning.However, in the present invention, a gas is further blown after the liquid is applied. The liquid remaining on the surface is removed, and then the liquid is again struck to wash the liquid. Direct impact forces are applied to more effectively remove and clean them.

Furthermore, the present invention makes the continuous spraying of the liquid intermittent or pulsating, thereby increasing the chances of direct hits and making the laminar gas flow on the surface to be cleaned caused by spraying thinner, so that the gas flow is reduced. Thus, the reduction of the collision force of the liquid fine particles due to the above is suppressed to a minimum, and the cleaning effect is further improved. Particularly, for articles having fine irregularities, the fine particles directly hit even their fine corners,
Even minute foreign matter is completely removed. In addition, since the above-mentioned operation, that is, the liquid layer and the gas flow are thinned, the effect is improved even in the case of the continuous spray cleaning, even for an article having a rough uneven surface or a surface having a general flat surface. You can do it. Not only that,
Cleaning solution consumption is 50% to achieve the same cleaning effect
Hereinafter, it has been experimentally confirmed that a minimum of 5% was sufficient.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first method of the present invention (hereinafter, unless otherwise specified). FIG. 2 is an enlarged view of the "A" part in the same figure. FIG. 3 is a first method of the present invention. FIG. 4 is an explanatory view of an example of moving an inner gun. FIG. 4 is an explanatory view of a locus of a gun moving on an object to be cleaned.
FIG. 6A and FIG. 6B are illustrations of the reversal of the liquid and gas guns in FIG. 6A and FIG. 6B. FIG. 7 is a second illustration of the present invention. FIG. 8 is a graph showing the opening / closing of a valve performing pulse spraying according to the second method versus time FIG. 9A is a side view of the state of pulse spray 9B
FIG. 9C is an explanatory view of the operation state of spray fine particles when the pulsed spray of the first wave hits the surface to be cleaned. FIG.
FIG. 10A is an explanatory diagram of the operation state of the fine particles at the end of the pulse spray of a wave. FIG. 10A is an enlarged explanatory diagram of the “B” portion on FIG. 9A. FIG.
Fig. 10C is an enlarged explanatory view of the "D" part on Fig. 9B. Fig. 10D is an enlarged explanatory view of the "E" part on Fig. 9C. Fig. 10E is an enlarged explanatory view of the "E" part. FIG. 11 shows three examples of pulsed spray timing. FIG. 12 shows a state in which liquid on the surface to be cleaned is removed and foreign matter is exposed. FIG.
FIG. 14 is an explanatory view of a third method of the present invention. FIG. 15 is a view of the same view as “T” arrow in FIG. FIG. 17 is an explanatory view of the third embodiment. FIG. 18 is a sectional view of the auxiliary air nozzle on the upper diagram. FIG. 19 is a first example of a method of applying vibration to the object to be cleaned (FIG. Fifth Embodiment FIG. 20 is the same as the second embodiment (Fifth Embodiment). FIG. 21 is an explanatory diagram of pulsed ejection by an extrusion nozzle. FIG. 22 is a block diagram of a second method by an extrusion method (FIG. Sixth Embodiment) No.
23 and 24 are explanatory diagrams of the third method by the extrusion method (seventh embodiment). FIG. 25 is an explanatory diagram of the pulsed discharge by the slit nozzle. FIG. 26 is a block diagram of the second method by the slit method. Figure (Eighth Embodiment) FIG. 27 is an explanatory view of a third method by a slit method (ninth embodiment) FIG. 28 is a conventional (hereinafter all referred to as conventional) shower type cleaning method FIG. Spray cleaning method FIG. 30 is an explanatory view of a liquid film generated on the surface to be cleaned in a continuous spray cleaning method.
FIG. 32 is an enlarged view of the upper part of the liquid film part. FIG. 32 is a view for explaining the behavior of fine particles on the surface to be cleaned in the continuous spraying. FIG. 33 is a perspective view of the continuous spraying cleaning method. Q "-" Q "
FIG. 35A is an enlarged explanatory view of the “H” part on FIG. 34. FIG. 35B is an enlarged explanatory view of the “I” part on FIG. 34. FIG. 35C is an “J” on FIG. 34.
FIG. 35D is an enlarged explanatory view of the “K” part on FIG. 34. FIG. 35E is an enlarged explanatory view of the “L” part on FIG. 34.
Enlarged explanatory view of the part in FIG. 35E in a dry state Description of main reference numerals 1,21,41,61,81,201… Liquid spray nozzle 11,31A, 31B, 51,71,91,251,271,301,321… Gas jet nozzle, 121… Auxiliary air spray nozzle, 231,241,261… Extrusion nozzle, 291,311… Slit nozzle, 7
0,90,140,250,300… Pulse controller, 204,214… Diaphragm, W, W ₁ , W ₂ ,…, W ₂₄ … Cleaning object, Ls… Liquid continuous spray wave, Lsp… Liquid pulse spray wave, Za, Zb, Z
c,…, Zr… foreign matter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-117389 (JP, A) JP-A-3-123681 (JP, A) JP-A-63-54982 (JP, A) JP-A-59-1984 160576 (JP, A) JP-A-61-212353 (JP, A) JP-A-63-107786 (JP, U) JP-B-58-35101 (JP, B2) JP-A-4-51507 (JP, Y2) Jikgyo Hei 3-44269 (JP, Y2) Jikgaku Sho 63-35831 (JP, Y2) Japanese Patent Publication No. 44-11797 (JP, B1) Jiggaku Sho 49-44525 (JP, Y1) (58) Fields surveyed (Int.Cl. ⁶ , DB name) H01L 21/304 H05K 3/00-3/46 B08B 1/00-11/04

Claims (3)

(57) [Claims] A liquid and a gas are sprayed from a liquid jet nozzle and a gas jet nozzle independently provided to an object to be cleaned (W) relatively moving between the nozzle and the object to be cleaned. And washing by spraying a liquid, and then blowing off the remaining liquid material sprayed on the surface of the object to be cleaned (W) by spraying a compressed gas to the surface of the object to be cleaned. In the method of spraying the liquid again and repeating these operations as necessary, the distance from the tip of the spray nozzle to the object to be cleaned is 75 mm or less, and the ejection speed of the liquid is 20 m / sec or more. A cleaning method wherein at least a liquid ejection cycle is intermittently ejected at a rate of 1 to 200 c / sec. 2. The cleaning method according to claim 1, wherein the cleaning is performed while at least the liquid spray nozzle traverses in a direction perpendicular to the moving direction of the object to be cleaned. 3. A cleaning method according to claim 1, wherein at least the liquid spray nozzle is constituted by a slit type nozzle.