JPH11279774A - Etching apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the component concn. of an etchant from varying with spray tanks by providing an etching apparatus having the plural spray tanks used by being connected with spray mechanisms for feeding the etchant from the storage tank of the etching apparatus to the nozzles of the spray tanks and reflux pipes for refluxing the etchant from the spray tanks to the storage tank. SOLUTION: This etching apparatus has the plural spray tanks 1 used by being connected, the one storage tank 2, the spray mechanisms 3 for feeding the etchant from the storage tank 2 to the nozzles of the spray tanks 1 and spraying the etchant and the reflux pipes 4 for refluxing the etchant from the spray tanks 1 to the storage tank 2. Since the etchant is refluxed from the plural spray tanks 1 to the one storage tank 2, the concn. of the etchant fed to the nozzles of the spray tanks 1 may be made the same. The etchant refluxed to the storage tank 2 is preferably stirred in order to make the concn. of the etchant fed to the nozzles of the spray tanks 1 further the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an etching apparatus,
In particular, the present invention relates to an etching apparatus used for manufacturing a printed wiring board by performing circuit processing on a copper-clad laminate.

[0002]

2. Description of the Related Art A printed wiring board is manufactured by forming an etching resist on a copper-clad laminate and spraying an etching solution from a nozzle in a spray tank of an etching apparatus to etch copper.

[0003] The conventional etching apparatus is configured so that an etching solution stored in the bottom of a spray tank is fed to a nozzle by a pump and sprayed onto a copper-clad laminate conveyed by a conveyor. The sprayed etchant returns to the bottom of the spray tank and is reused.

[0004] In the etching solution stored at the bottom of the spray tank, the etched copper is accumulated as copper chloride, and the components of the etching solution are also consumed. Therefore, the component concentration of the etching solution is measured, a new etching solution is appropriately replenished, and a part of the etching solution is caused to overflow to keep the component concentration of the etching solution constant.

[0005] Etching may not be completed in a single spray tank, such as when the copper foil of a copper-clad laminate is thick,
In that case, a plurality of spray tanks are connected. When connecting a plurality of spray tanks, the bottom of each spray tank was communicated and the etchant was circulated by a circulation pump so that the component concentration of the etchant in each spray tank and the accumulated amount of copper chloride did not vary. .

[0006]

However, for example, when etching a copper-clad laminate having a copper foil thickness of 70 μm by connecting three spray tanks, half of the first spray tank and half of the second spray tank are used. In order for 30% of the remaining copper to be etched in the third spray tank,
The difference in the fluctuation of the component concentration of the etching solution becomes large depending on the spray tank, and this difference was not always eliminated by the circulation of the etching solution by the circulation pump. If the component concentration of the etching solution is different depending on the spray tank, predetermined etching is not performed and copper to be etched remains, which causes a residual copper defect. SUMMARY OF THE INVENTION It is an object of the present invention to provide an etching apparatus having a plurality of spray tanks used in connection with each other so that the component concentration of an etching solution does not differ between spray tanks.

[0007]

According to the first aspect of the present invention, a plurality of spray tanks 1, a single storage tank 2, and an etching solution are sent from the storage tank 2 to the nozzles of the spray tank 1 for use in connection with each other. The etching apparatus is provided with a spray mechanism 3 for supplying and spraying and a reflux pipe 4 for refluxing the etchant from the spray tank 1 to the storage tank 2 (see FIG. 1).

[0008] Since the etching liquid is returned from the plurality of spray tanks 1 to one storage tank 2, the concentration of the etching liquid supplied to the nozzles of the spray tank 1 can be made equal.

In order to further equalize the concentration of the etching solution sent to the nozzle of the spray tank 1, it is preferable to stir the etching solution refluxed to the storage tank 1. A stirrer may be used to stir the etchant, but since the etchant is corrosive, inspection and maintenance of the stirrer is required. Therefore, it is preferable that the etching solution can be stirred without using a stirring device.

According to a second aspect of the present invention, the storage tank 2 has an oval shape, a longitudinal partition plate 5 is provided at the center thereof, and the discharge direction of the etching liquid refluxed from each spray tank 1 is the same direction. 2. The etching apparatus according to claim 1, wherein the etching apparatus is configured to be along the edge in the longitudinal direction (see FIG. 2).

The storage tank 2 is formed into an elliptical shape, and a longitudinal partition plate 5 is provided at the center thereof so that the direction of discharge of the etching liquid refluxed from each spray tank 1 is the same direction and along the edge in the longitudinal direction. With this configuration, the refluxed etchant flows around the partition plate 5, whereby the etchant is stirred.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. As the spray tank 1, a well-known spray tank can be used, and there is no particular limitation. The spray mechanism 3 includes a pump P for supplying the etching liquid from the storage tank to a nozzle (not shown) in the spray tank 1, a storage tank 2, and a pump P.
And a feed pipe 11 connecting the nozzles.

The etchant sprayed from the nozzle is returned from the spray tank 1 to the storage tank 2 by the return pipe 4. It is preferable that the reflux pipe 4 is attached to the bottom of the spray tank 1 so that reflux is performed by utilizing the head between the bottom of the spray tank 1 and the discharge port 4a because no power is required.

As shown in FIG. 2, it is preferable that the storage tank 2 has an oval shape and a longitudinal partition plate 5 is provided at the center thereof. The dimensions and the like of the storage tank 2 are appropriately selected according to the amount of the etchant to be stored.

As shown in FIG. 1, the discharge port 4a of the reflux pipe 4 is provided along the longitudinal edge of the storage tank 2 and in the same direction, because the flow of the refluxing etchant is generated. preferable.

In order to generate a flow in the refluxing etchant, a drop between the bottom of the spray tank 1 and the discharge port 4a is defined as
The etching liquid is about 10 to 30 cm from the discharge port 4 a at an angle of 10 to 25 degrees with respect to the horizontal plane from the discharge port 4 a.
It is preferable to provide the discharge port 4a so as to discharge at the position of m.

[0017]

EXAMPLE 1 An etching solution of 6 liters per minute was supplied at a pump pressure of 215 kPa from a storage tank having an oval shape and having a longitudinal partition in the middle to each nozzle of a spray tank connected in three tanks. did. Also, the specific gravity etching solution (1.320) is returned to the storage tank from the lower part of each spray tank, the head between the inlet of the reflux pipe and the discharge port is set to 20 cm, and the etching liquid refluxing the discharge port of the reflux pipe is horizontal. Is ejected at an angle of 20 degrees. The storage tank had an oval shape and a longitudinal partition plate was provided at the center. 614m
m square double-sided copper-clad laminate (1.6 mm thick, copper foil thickness 7
0 μm, manufactured by Hitachi Chemical Co., Ltd., MCL-E-67
(Product name) was fed into the spray tank at a conveyor speed of 3 m / min. The etching solution used was 19.0% by weight of ferric chloride and 1 ml / l of 35% hydrochloric acid. When the entire surface of the 100 double-sided copper-clad laminates was etched, no residual copper defect in which copper to be etched remained was generated. After the etching of 100 double-sided copper-clad laminates, the concentration of ferric chloride in the etching solution sprayed into each spray tank was measured. As a result, the concentration of ferric chloride in the first tank was 18.5% by weight. %, The concentration of ferric chloride in the second tank was 19.0% by weight, and the concentration of ferric chloride in the third tank was 19.0% by weight.

COMPARATIVE EXAMPLE The bottom of a spray tank connected to three tanks was communicated with a communication pipe, the etching solution was circulated by a circulation pump, and the etching solution was sent from the lower part of the spray tank to the nozzle of the spray tank without being returned to the storage tank. Except for feeding, 100 sheets of double-sided copper-clad laminates were entirely etched in the same manner as in Example 1. At this time, 10% of residual copper defects in which copper to be etched remains were generated. After the etching was completed, the concentration of ferric chloride in the etching solution sprayed into each spray tank was measured.
5% by weight, the concentration of ferric chloride in the second tank is 18.1% by weight,
The ferric chloride concentration in the third tank was 18.6% by weight.

[0019]

According to the present invention, there is provided an etching apparatus having a plurality of spray tanks connected and used.
The difference in the concentration of the etching solution sent to the spray tank can be eliminated, and the residual copper defect can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an etching apparatus according to one embodiment of the present invention.

FIG. 2 is a perspective view of a storage tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spray tank 2 Storage tank 3 Spray mechanism 4 Reflux pipe 4a Discharge port 5 Partition plate 11 Feed pipe P pump

Claims (2)

[Claims] 1. A plurality of spray tanks used in combination,
An etching apparatus comprising: one storage tank; a spray mechanism for supplying and spraying an etching liquid from the storage tank to a nozzle of the spray tank; and a reflux pipe for returning the etching liquid from the spray tank to the storage tank. 2. A storage tank having an elliptical shape, a longitudinal partition plate provided in the center thereof, and a discharge direction of an etching liquid refluxed from each spray tank being in the same direction and along the edge in the longitudinal direction. The etching apparatus according to claim 1, wherein the etching apparatus comprises: