JP2020168609A - Defoaming method and defoaming device - Google Patents

Abstract

To provide a defoaming method that can be used for process of manufacturing a printed wiring board readily and inexpensively, and to provide a defoaming device.SOLUTION: A defoaming method for removing foam floating on a surface of liquid includes the steps of: storing liquid containing foam in a liquid tank; arranging a defoaming mesh horizontally in a position separated upward from the surface of liquid inside the liquid tank; and breaking the foam floating on the surface of liquid when the defoaming mesh comes into contact with the foam.SELECTED DRAWING: Figure 1

Description

The present invention relates to a defoaming method and a defoaming device used in a manufacturing process of a printed wiring board or the like.

The semi-additive method is known as one of the methods for manufacturing a printed wiring board having a fine pitch in recent years. In the semi-additive method, a seed layer is provided on an insulating layer or an insulating substrate by, for example, electroless plating, the seed layer is covered with a plating resist having an open pattern portion, and the seed layer portion exposed from the opening of the plating resist is electrolyzed. This is a method in which a circuit pattern is formed by plating, then the plating resist is removed with a stripping solution, and then the seed layer portion other than the circuit pattern is removed by etching to form a conductor circuit layer having the circuit pattern.

In the manufacturing process of such a printed wiring board, for example, in the washing step of the printed wiring board after removing the plating resist with a stripping solution, the stripping solution adhering to the substrate surface is mixed with the washing water in the washing tank and stirred. This may generate bubbles, which may overflow out of the flush tub. Therefore, it is desirable to provide a defoaming device for removing bubbles in the washing tank.

Patent Document 1 proposes a defoaming device that removes bubbles contained in a liquid such as ink or oil, and this defoaming device has a bag shape that covers the liquid in a liquid container from above the liquid surface to the inside of the liquid. The liquid containing bubbles is supplied into the net from the lower end opening of the net, and the liquid from which the bubbles have been removed is taken out of the liquid container through the net from the bottom of the net, while rising along the inner surface of the net and above the liquid surface. The gas that has broken out of the bubbles is taken out of the liquid container from the top of the net through the net.

Further, Patent Document 2 proposes a defoaming device that sucks and removes bubbles generated from a liquid such as cooling water mixed with a substance having a surface-active effect in a tank for storing the liquid. The foaming device floats on the liquid level of the liquid in the tank, and the bubbles generated on the liquid level of the liquid in the tank are discharged from the suction port located near the liquid level of the impeller driven by the motor in the device. It is removed by suction by rotation.

Japanese Unexamined Patent Publication No. 2006-320800 JP-A-2007-222721

However, the apparatus described in Patent Document 1 only takes out the gas generated from the broken bubbles rising to the liquid surface from the upper part of the net, and does not have a function of positively eliminating the bubbles. Further, the device described in Patent Document 2 sucks and removes bubbles from a suction port located near the liquid surface by the rotation of a motor-driven impeller in the device, which makes the device complicated and expensive.

An object of the present invention is to provide an easy and inexpensive defoaming method and defoaming device that can be used in the manufacturing process of a printed wiring board or the like.

The defoaming method of the present invention
A method of removing bubbles that have floated on the surface of a liquid.
The fact that the liquid containing bubbles is stored in the liquid tank
The defoaming net is placed horizontally at a position above the liquid level in the liquid tank, and
When the bubbles floating on the surface of the liquid come into contact with the defoaming net and break,
Includes.

In the defoaming method of the present invention, preferably, the defoaming net is detachably arranged at a predetermined height position in the liquid tank, or is formed on the foam on the liquid surface of the liquid in the liquid tank. Floating with buoyancy against bubbles.

Further, the defoaming device of the present invention is
A device that removes bubbles that have floated on the surface of a liquid.
A liquid tank that stores liquid containing bubbles,
A defoaming net that is placed horizontally at a position above the liquid level of the liquid in the liquid tank and comes into contact with bubbles floating on the liquid level to break the bubbles.
Is equipped with.

In the defoaming device of the present invention, preferably, the defoaming net is detachably arranged at a predetermined height position in the liquid tank, or is formed on the foam on the liquid surface of the liquid in the liquid tank. Floating with buoyancy against bubbles.

(A) and (b) are perspective views and sectional views which show one Embodiment of the defoaming apparatus of this invention used in one Embodiment of the defoaming method of this invention. (A) and (b) are perspective views and cross-sectional views showing another embodiment of the defoaming apparatus of the present invention used in another embodiment of the defoaming method of the present invention. It is a perspective view which shows one modification of the defoaming apparatus of the other embodiment.

FIG. 1 (a) is a perspective view showing an embodiment of the defoaming device of the present invention used in one embodiment of the defoaming method of the present invention, and FIG. 1 (b) is an extinguishing of the embodiment. It is sectional drawing which shows the foaming apparatus. In the defoaming device of this embodiment, for example, in the manufacturing process of the printed wiring board, for example, in the water washing step of the printed wiring board after removing the plating resist with the stripping liquid, the substrate to which the stripping liquid adheres is immersed on the surface thereof. A recovery water washing tank 1 as a liquid tank for holding the washing water L as a liquid containing bubbles, which is used when washing away the peeling liquid and generates bubbles due to the mixing of the peeling liquid, and a recovery water washing tank 1 thereof. It is equipped with a defoaming net 2 arranged inside.

In the recovery water washing tank 1, washing water L is supplied and stored in the tank via a water supply pipe (not shown), and a substrate (not shown) having, for example, a plating resist stripping solution adhered to the surface is immersed in the washing water L. After repeating the cleaning step of cleaning and removing the stripping solution with washing water L and taking out the substrate after cleaning and removing the stripping solution for a predetermined number of substrates, the inside of the tank is in the tank via a drain pipe (not shown). The wash water L is drained. In this cleaning step, a relatively large amount of bubbles are generated in the cleaning water L mixed with the stripping liquid, and the upper surface BS of the bubbles is normally above the water surface LS and from the water surface LS without the defoaming net 2. It reaches a generally predetermined height, for example, a maximum height of 200 mm above the water surface LS.

The defoaming net 2 is detachably arranged with respect to the recovery water washing tank 1 so that it can be removed so as not to interfere with the immersion and removal of the substrate in the cleaning water in the substrate cleaning step. The defoaming net 2 is provided on a metal net body 2a such as stainless steel and an outer frame of the net body 2a, and is engaged with the upper end edge of the recovery water washing tank 1 at a folded portion at the upper end. It has a plurality of metal plate-shaped hooks 2b such as, etc., and the net body 2a is at a normal position at a predetermined distance upward from the water surface LS of the washing water L in the recovery water washing tank 1, for example, 5 mm. It is located horizontally at a height lower than the upper surface BS of the foam.

The defoaming method of the above embodiment using the defoaming device of this embodiment is a method of removing bubbles floating on the water surface LS of the washing water L, and the washing water L containing the bubbles is collected in the water washing tank 1. The net body 2a of the defoaming net 2 is horizontally arranged at a position separated upward from the water surface LS of the washing water L in the recovery water washing tank 1, and is placed on the water surface LS of the washing water L. It includes that the floating bubbles come into contact with the net body 2a of the defoaming net 2 and break.

Here, the reason why the bubbles come into contact with the net body 2a and break is that the bubbles become stable when the bubble films adjacent to each other have an angle of 120 degrees with each other, whereas the bubbles become stable. It is presumed that the foam film in contact with 2a cannot maintain its 120-degree angle due to adhesion to the main body 2a, and the foam becomes unstable.

Therefore, according to the defoaming method of this embodiment using the defoaming device of this embodiment, bubbles can be easily erased and removed by an inexpensive configuration in the manufacturing process of the printed wiring board.

FIG. 2A is a perspective view showing another embodiment of the defoaming device of the present invention used in another embodiment of the defoaming method of the present invention, and FIG. 2B is a perspective view thereof. It is sectional drawing which shows the defoaming apparatus of embodiment. Similar to the previous embodiment, the defoaming device of this embodiment also has the release liquid adhering to the surface in, for example, in the manufacturing process of the printed wiring board, for example, in the water washing step of the printed wiring board after removing the plating resist with the release liquid. The recovery water washing tank 1 as a liquid tank for retaining the washing water L as a liquid containing bubbles, which is used when the substrate is immersed and the stripping liquid is washed away, and bubbles are generated due to the mixing of the stripping liquid. , A defoaming net 2 arranged in the recovery water washing tank 1 is provided.

Since the recovery water washing tank 1 is not much different from that in the previous embodiment, the defoaming net 2 will be mainly described below. The defoaming net 2 in this embodiment includes, for example, a metal net body 2a such as stainless steel and a plurality of elongated bag-shaped floats 2c made of light resin such as polypropylene provided on the outer frame of the net body 2a. Due to the buoyancy of the float 2c with respect to the foam, the net body 2a is separated from the water surface LS of the washing water L in the recovery water washing tank 1 by a predetermined distance, for example, 5 mm, and is normally located on the upper surface of the foam. It is located horizontally at a height lower than BS. The float 2c may have a frame shape that overlaps the outer side or the lower side of the outer frame of the net body 2a instead of the plurality of bag-shaped floats.

The defoaming method of this embodiment using the defoaming device of this embodiment is a method of removing bubbles floating on the water surface LS of the washing water L, and is the same as the defoaming method of the previous embodiment. The wash water L containing the above is stored in the recovery water washing tank 1, and the net body 2a of the defoaming net 2 is horizontally arranged at a position separated upward from the water surface LS of the washing water L in the recovery water washing tank 1. This includes the fact that the bubbles floating on the water surface LS of the washing water L come into contact with the net body 2a of the defoaming net 2 and break.

Therefore, even by the defoaming method of this embodiment using the defoaming device of this embodiment, bubbles can be easily erased and removed by an inexpensive configuration in the manufacturing process of the printed wiring board.

FIG. 3 is a perspective view showing a modified example of the defoaming net 2 of the defoaming device of the other embodiment. In this modification, the net body 2a of the defoaming net 2 is made of light resin and has buoyancy against bubbles. The resin net body 2a is reinforced with, for example, a metal frame-shaped and brace-shaped reinforcing material 2d such as stainless steel, and the net body 2a is provided with the washing water L in the recovery water washing tank 1 on the reinforcing material 2d. A plurality of metal weights 2e, such as stainless steel, are suspended so as to be separated from the water surface LS of the water surface and float in the foam at a position appropriately submerged from the surface BS of the foam.

Even by the defoaming method of this embodiment using the defoaming device of the above-described embodiment including the defoaming net 2 of this modified example, bubbles can be easily eliminated by an inexpensive configuration in the manufacturing process of the printed wiring board. Can be removed.

Although described above based on the illustrated examples, the defoaming method and defoaming device of the present invention are not limited to the above examples, and can be appropriately changed within the scope of the claims, for example. The defoaming method and defoaming device of the present invention may be used for applications other than the manufacturing process of the printed wiring board and the manufacturing process of the printed wiring board.

Further, the configuration of the defoaming net 2 is not limited to the above example, and other materials and configurations may be used.

1 Recovery water washing tank 2 Defoaming net 2a Net body 2b Hook 2c Float 2d Reinforcing material 2e Weight BS Foam top surface L Washing water LS Water surface

Claims (6)

In a defoaming method that removes bubbles floating on the surface of a liquid
The fact that the liquid containing bubbles is stored in the liquid tank
The defoaming net is placed horizontally at a position above the liquid level in the liquid tank, and
When the bubbles floating on the surface of the liquid come into contact with the defoaming net and break,
Includes. The defoaming method according to claim 1.
The defoaming net is detachably arranged at a predetermined height in the liquid tank. The defoaming method according to claim 1.
The defoaming net floats on bubbles on the liquid surface of the liquid in the liquid tank by buoyancy against the bubbles. In a defoaming device that removes bubbles floating on the surface of a liquid
A liquid tank that stores liquid containing bubbles,
A defoaming net that is placed horizontally at a position above the liquid level of the liquid in the liquid tank and comes into contact with bubbles floating on the liquid level to break the bubbles.
Is equipped with. The defoaming device according to claim 4.
The defoaming net is detachably arranged at a predetermined height in the liquid tank. The defoaming device according to claim 4.
The defoaming net floats on bubbles on the liquid surface of the liquid in the liquid tank by buoyancy against the bubbles.

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