JPH11100684A - Specific gravity measuring instrument for etchant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sp. gr. measuring instrument of an etchant capable of extremely decreasing the errors by air bubble intrusion and/or the errors by a liquid temp. fall and rapidly measuring the sp. gr. of the etchant. SOLUTION: This sp. gr. measuring instrument for the etchant has an inside cylinder 6 which houses a gravimeter and has piping for introducing the etchant to be measured of the sp. gr. at the bottom thereof, an outside cylinder 5 which encloses the outside of this inside cylinder and has the constitution to allow the passage of the etchant and a control valve 2 which collects the etchant to be measured of the sp. gr. in the inside cylinder and is connected to piping 1 for standing the etchant still.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for measuring the specific gravity of an etchant, and more particularly to an apparatus for measuring the specific gravity of an etchant for use in an etching apparatus having a specific gravity control mechanism.

[0002]

2. Description of the Related Art The specific gravity of an etching solution is a major factor influencing the etching performance. For example, ferric chloride is used for etching copper, but if the specific gravity of the etchant changes, the etching rate changes, and the circuit width of the printed circuit board deviates from the control width. Also, in the etching of iron alloys,
As the specific gravity of the etchant decreases, the roughness of the etched surface increases, and as the specific gravity increases, the etching rate decreases. As described above, the measurement of the specific gravity of the etchant is the most important item for managing the etchant.

In order to accurately measure the specific gravity of an etching solution, a measuring device or an etching solution container is placed in a constant temperature bath, air bubbles are removed from the etching solution, and after the temperature reaches a predetermined temperature, a float glass is used. What is necessary is just to measure with a hydrometer or the like. However, this method is not only complicated, but also unsuitable for managing specific gravity, which changes gradually because measurement requires time. The specific gravity measuring device that has been used in production sites and the like is to extract a sample (etching solution) and place it in a cylindrical container having a valve for standing still from a pipe branched from a circulation pump for the etching solution. And the etching solution discharged by overflow is returned to the etching tank through a dedicated pipe.
If the specific gravity of the etchant is measured by this apparatus, the specific gravity can be measured in a short time, but there are the following problems.

[0004]

That is, the etching in the etching apparatus is usually performed by a spray method. For this reason, a large amount of bubbles are contained in the etching solution, and it is necessary to accurately measure the specific gravity as it is. Can not. Although the bubbles can be removed by leaving the etchant still, it is necessary to prolong the standing time in order to obtain an accurate value. The specific gravity could not be measured. That is, the error and / or
Or an error due to a decrease in the liquid temperature could not be avoided.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an etching solution specific gravity measuring apparatus capable of measuring the specific gravity of an etching solution in a short time with a very small error due to air bubble mixing and / or an error due to a decrease in liquid temperature. It is in.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is,
The present invention relates to an inner cylinder containing a hydrometer and having a pipe for introducing an etching solution to be measured for specific gravity at the bottom thereof, and an outer cylinder surrounding the inner cylinder and having a configuration through which the etching solution can flow. And a control valve connected to the pipe for collecting an etching solution to be measured for specific gravity in the inner cylinder and for allowing the etching solution to stand still. Is to do.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus for measuring the specific gravity of an etching solution according to the present invention is characterized in that, when an etching solution to be measured for specific gravity is collected in an inner cylinder and allowed to stand still, the etching solution is kept flowing in an outer cylinder to thereby collect the etching liquid. Bubbles can be removed while maintaining the temperature of the liquid at the etching temperature.

That is, by using the apparatus for measuring the specific gravity of the etching solution of the present invention, the conventional problems can be eliminated at a glance and the specific gravity can be measured with high accuracy. Therefore, the specific gravity of the etchant can be controlled with high accuracy, which contributes to a decrease in the defective rate of the product to be etched.

In the apparatus for measuring the specific gravity of an etching solution according to the present invention, the material of the inner tube and the outer tube may be selected from those having corrosion resistance to the etching solution. Is mentioned.

Next, an apparatus for measuring the specific gravity of an etching solution according to the present invention will be described with reference to FIGS. An outer cylinder (5) is provided so as to surround the outside of the inner cylinder (6). By opening the control valve (2) via the etching solution circulation pump (9), the etching solution is introduced into the inner cylinder (6) through the etching solution introduction pipe (1). The inner cylinder (6) has a hydrometer (7), which floats on the introduced etching solution. When the inner cylinder (6) is filled with the etchant, the control valve (2) is closed, the etchant is allowed to stand for a predetermined time to remove bubbles, and then the specific gravity of the etchant is measured by a hydrometer (7). The upper end of the inner cylinder (6) is positioned at a position slightly higher than the level of the etching solution in the outer cylinder (5). It is preferable to prevent the etchant in () from flowing backward from above.

When the specific gravity measurement is completed, the control valve (2) is opened to allow the etching solution to flow, and the overflowing etching solution is returned to the etcher (11) through the overflow pipe (8). When the specific gravity is measured again, the control valve (2) is closed again to allow the etching solution to stand still, and thereafter, the specific gravity is measured in the same manner.

Here, the etching solution in the inner cylinder (6) need not always be circulated except for the specific gravity measurement time, but should be circulated from the viewpoint of controlling the specific gravity of the etching solution with high accuracy. Is preferred. In the apparatus for measuring the specific gravity of an etching solution according to the present invention, a control valve is also provided on the outer cylinder (5).
The etchant is passed through the etchant introduction pipe (4) via (3). Since the etching solution flowing in the outer tube (5) has the same temperature as the etching solution in the etcher (11), the etching solutions in the inner tube (6) and the inner tube (6) are also maintained at the same temperature. . Therefore, the etching solution in the outer cylinder (5) is flowing at least during the measurement of the specific gravity, and the overflowing etching solution is passed through the overflow pipe (8) to the etcher (1).
Returned to 1). Further, a control valve (10) is provided to control circulation of the etching solution to the etcher (11).

The control valve (3) for controlling the flow of the etching solution into the outer cylinder (5) is not essential. Even if the etching solution is circulated in the outer cylinder (5) only by the hydraulic pressure of the etching solution circulation pump. Although it is good, it is more efficient to install the control valve (3).

[0014]

EXAMPLES Hereinafter, the apparatus for measuring the specific gravity of an etching solution of the present invention will be further described with reference to examples. Example 1 A lead frame (42 alloy) was etched with an etcher having an effective etching length of 1.8 m and a bath capacity of 400 liters. As an etchant, Adeka Kelmika LF-346 and LAD-100 manufactured by Asahi Denka Kogyo Co., Ltd.
Was used as an etching liquid control device. As shown in FIG. 3, the apparatus for measuring the specific gravity of the etchant of FIG. 1 was attached to a pipe branched from the etchant circulation pump of the etching apparatus, and a return pipe (overflow pipe) (8) for the etchant was connected to the etcher.

While the etching of the lead frame was continued, the specific gravity was sequentially measured with a float type hydrometer. The measuring method is as follows. After flowing the etching solution into both the outer cylinder (5) and the inner cylinder (6) for 5 minutes, the control valve (2) at the inlet of the inner cylinder is closed and the etching solution is allowed to stand for 5 minutes. The specific gravity of the etching solution was measured. During this time, the etching liquid was kept flowing through the outer cylinder (5).

Separately, a sample of the etching solution is collected,
The sample was placed in a container in a thermostat and set to a measurement temperature, and then the specific gravity was measured and compared with the value measured above. The results were as shown in Table 1. It is understood that the use of the etching liquid specific gravity measuring apparatus of the present invention facilitates highly accurate specific gravity measurement.

[0017]

[Table 1] * 1: Measured at an etchant temperature of 50 ° C * 2: Measured at a constant temperature bath temperature (measured temperature) of 50 ° C

Example 2 A printed wiring board was etched using the same etcher as in Example 1 except that the etching solution was ferric chloride. The same operation was performed using the same hydrometer as in Example 1. Table 2 shows the results.

[0019]

[Table 2] * 3: Measured at etchant temperature of 45 ° C. * 4: Measured at constant temperature bath temperature (measurement temperature) of 45 ° C. As a result of changing the conveyor speed during etching according to the specific gravity measurement result, no defective product was generated.

Comparative Example 1 The same operation as in Example 2 was performed using the same etcher as in Example 1. However, the apparatus for measuring the specific gravity of the etchant shown in FIG. 2 was used. That is, the apparatus for measuring the specific gravity of an etching solution shown in FIG. 2 includes an etching solution container (6 ′) for allowing the etching solution to stand still, and an etching solution container (6 ′) for measuring the specific gravity of the etching solution. Specific gravity meter
This is a one-cylinder specific gravity measuring device composed of (7 ').
In FIG. 2, (1 ′) denotes an etching solution introduction pipe for introducing the etching solution into the etching solution storage section (6 ′),
(2 ′) is a control valve for controlling the flow of the etchant into the etchant storage section (6 ′), and (8 ′) returns the etchant from the etchant storage section (6 ′) to the etcher. Overflow piping for In this specific gravity apparatus, the specific gravity of the etchant was measured by setting the etching solution to stand still for 1 minute and 5 minutes. The results are as shown in Table 3, which indicates that the measurement accuracy is low.

[0021]

[Table 3] * 5: Measured at an etchant temperature of 45 ° C * 6: Measured at a constant temperature bath temperature (measurement temperature) of 45 ° C

[0022]

The effect of the present invention is to provide an etching solution specific gravity measuring apparatus capable of measuring the specific gravity of an etching solution in a short time with very few errors due to air bubbles and / or errors due to a decrease in liquid temperature. It is in. The use of the apparatus for measuring the specific gravity of an etchant according to the present invention makes it possible to easily and accurately measure the specific gravity of an etchant, thereby contributing to accurate management of the etchant.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an apparatus for measuring the specific gravity of an etching solution according to the present invention.

FIG. 2 is a diagram illustrating a conventional apparatus for measuring the specific gravity of an etching solution.

FIG. 3 is a view showing an embodiment of an etching apparatus to which an apparatus for measuring a specific gravity of an etching solution according to the present invention is attached.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching liquid introduction pipe 2 Control valve 3 Control valve 4 Etching liquid introduction pipe 5 Outer pipe 6 Inner pipe 7 Density meter 8 Overflow pipe 9 Etching liquid circulation pump 10 Control valve 11 Etcher 2 'Control valve 6' Etching liquid storage section 7 ' 8 'overflow pipe

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshikatsu Kubota Asahi Denka Kogyo Co., Ltd., 7-35 Higashiogu, Arakawa-ku, Tokyo

Claims (1)

[Claims] An inner cylinder containing a hydrometer and a pipe for introducing an etching solution for specific gravity measurement into a bottom portion;
An outer cylinder surrounding the outer periphery of the inner cylinder and having a configuration through which an etching solution can pass; and an outer cylinder connected to the pipe for collecting an etching solution to be measured for specific gravity in the inner cylinder and allowing the etching solution to stand still. An apparatus for measuring a specific gravity of an etchant, comprising a control valve.