JPH0313718Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an automatic absorbance measuring device.

FIG. 1 is a simplified block diagram of a prior art automatic absorbance measuring device. A plating solution 62 used for electroless copper plating is stored in the tank 61 . In order to measure the copper ion concentration in the plating solution 62, a pipe line 63 is inserted into the plating solution 62. A metering pump 64 is interposed in the conduit 63, and a portion of the plating liquid 62 is supplied to the absorbance cell 65 as a test liquid by the metering pump 64.
The absorbance cell 65 is provided with an absorbance detection section 66 . The absorbance detection section 66 measures the absorbance of the test solution colored blue by divalent copper ions. The measured test liquid is discharged from the pipe line 67.

The amount of copper ion is determined from the absorbance value thus measured. When the composition of the plating liquid 62 changes and the hydrogen ion index changes, the coloration of divalent copper ions changes. In reality, changes in the hydrogen ion index of the plating solution 62 in the bath 61 where electroless copper plating is performed ranges as much as ±0.5 of the central value, so it is difficult to accurately quantify copper ions using such prior art techniques. It was difficult to quantify copper ions.

For this reason, in order to adjust the hydrogen ion index of the test solution, a sulfuric acid acidic solution or the like was manually titrated, but this was a complicated process and required a long time to measure the absorbance.

The purpose of the present invention is to solve the problems of the prior art and provide an automatic absorbance measurement device that can perform measurements in a short time and also allows accurate quantification.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system diagram showing the configuration of an automatic absorbance measuring device according to an embodiment of the present invention. The automatic absorbance measuring device 1 includes a test solution collection means 2, a reaction cell 3 to which the test solution is supplied, a hydrogen ion index measurement means 4 provided in the reaction cell 3, and a measurement value of the hydrogen ion index measurement means 4. an adjusting means 6 for adjusting the hydrogen ion index by dropping a sulfuric acid acidic solution 5 according to the conditions; and an absorbance measuring means 7 for measuring the absorbance of the test solution whose hydrogen ion index has been adjusted in the reaction cell 3. including.

The test solution sampling means 2 is provided to collect a certain amount of test solution from a solution to be measured, such as a plating solution 9 in an electroless copper plating tank 8 . The sampling means 2 roughly includes a pipe line 10, a metering pump 11 that is interposed in the pipe line 10 to collect a test liquid, and a quantitative sampler 12 that supplies a fixed amount of test liquid to the reaction cell.
and a supply pipe line 13 for supplying the test liquid from the collector 12 to the reaction cell 3. One end of the pipe line 10 is inserted into the plating liquid 9, and a flexible pipe part 14 is formed in a part of the pipe line 10 between the electroless copper plating tank 8 and the metering pump 11. The supplied cooling water 16 cools the corrugated pipe section 14 . As a result, the plating solution 9 is brought to approximately room temperature. The quantitative sampler 12 consists of a lower tube section 17 serving as a negative electrode with which the other end of the tube 10 is communicated, and an upper tube section 18 above the lower tube section 17. A metering valve 19 is provided at the lower end of the lower pipe portion 17, and a supply pipe line 13 is connected to the metering valve 19. Upper end 69 of lower tube portion 17
is opened near the lower end of the upper tube portion 18, and a lower end of a positive electrode 20 made of a conductive material is disposed corresponding to the upper end 69. The positive electrode 20 is suspended in a plug 21 that is tightly sealed at the upper end of the upper tube portion 18 . A drain pipe 22 is connected to the vicinity of the lower end of the upper pipe portion 18 . A pipe line 23 is provided in the lower pipe part 17.
are set up consecutively. Pure water 25 is supplied to the pipe line 23 via a pump 24 .

The plating liquid 9 is collected into a quantitative sampler 12 by driving a metering pump 11 at predetermined time intervals, for example, every 5 minutes. Since the plating liquid 9 is electrically conductive, when a certain amount is put into the lower tube part 17 of the quantitative sampler 12, it is electrically connected to the positive electrode 20. As a result, the driving of the metering pump 11 is stopped, and a predetermined amount of the plating liquid 9 is collected as a test liquid in the metering sampler 12. This test liquid is supplied to the reaction cell 3 from the supply pipe line 13 with the metering valve 19 opened.

The reaction cell 3 is placed on a stirrer 26 for stirring the inside of the reaction cell 3, and is realized by, for example, a beaker. Inside the reaction cell 3,
A glass electrode 27 of a PH meter (not shown) and a temperature detector 28 consisting of a thermistor or the like are inserted. In the reaction cell 3, a conduit 29, a conduit 30, and a conduit 31 are opened through a lid 32 of the reaction cell 3. A drain pipe 33 is opened near the bottom of the reaction cell 3 . An additive solution 35 for stabilizing the test liquid collected in the reaction cell 3 is fed into the pipe line 29 by driving a metering pump 34 .

In the reaction cell 3, the test liquid collected by the sampling means 2 and the additive solution 35 are stirred and mixed by driving the stirrer 26 to rotate the stirrer piece 44. The hydrogen ion index measuring means 4 includes the PH meter and a temperature detector 28. The hydrogen ion index of the test liquid mixed with the additive solution 35 is measured by the glass electrode 27, and corrected according to the temperature of the test liquid measured by the temperature detector 28.

The hydrogen ion index of plating liquid 9 is, for example, 12.5.
The hydrogen ion index at which the blue coloration of divalent copper ions is stable is 9.5. Depending on the measured hydrogen ion index of the test solution, the sulfuric acid acidic solution 5 is added to set the hydrogen ion index of the test solution in the reaction cell 3 to, for example, 9.5. For this reason, adjustment means 6 for adjusting the hydrogen ion index is provided. The adjusting means 6 generally includes the sulfuric acid acid solution 5 and the pipe line 3.
0, and a metering pump 36 interposed in a conduit 30 for feeding the sulfuric acid acidic solution 5. Metering pump 36
A flow rate measuring section 37 is interposed in the conduit 30 on the upstream side of the flow rate measuring section 37, and a flow rate calibration valve 38 is interposed in the conduit 30 on the upstream side of the flow rate measuring section 37. Flow rate measuring section 37
A branch line 39 is provided in the line 30 between the flow rate calibration valve 38 and the flow rate calibration valve 38 . Therefore, the metering pump 36
is driven, and according to the measured value obtained by the hydrogen ion index measuring means 4, the sulfuric acid acidic solution 5 is introduced into the reaction cell 3 to a predetermined hydrogen ion index, e.g.
It is dripped via line 30 until it reaches 9.5.

The measuring means 7 includes a measuring section 41 for measuring the absorbance of the test solution whose hydrogen ion index has been adjusted in the reaction cell 3, a conduit 42 for supplying the test solution to the measuring section 41, and a conduit 42.
and a metering pump 43 interposed between. Conduit 4
2 has an opening near the bottom of the reaction cell 3 and is immersed in the test liquid. When the metering pump 43 is driven, the test liquid is supplied to the measuring section 41 via the conduit 42 . The measurement section 41 includes an absorbance cell 45 and an absorbance detection section 46. The test liquid is supplied to the absorbance cell 45 , and after the absorbance of the test liquid is measured by the absorbance detector 46 , it is discharged through the drain pipe 47 .

The metering pumps 11, 34, 43 are controlled by a control device (not shown) and are driven in accordance with the time intervals to be measured. This control device drives the metering pump 36 in accordance with the measured value of the hydrogen ion index measuring means. Every time the measurement of the absorbance of the test liquid is completed, the reaction cell 3 is filled with washing water 49 via the pipe line 31 by driving the pump 48 . As a result, the reaction cell 3 is cleaned, and the cleaning water after cleaning is pumped to the drain pipe 3 by driving the pump 50.
3. Further, the collector 12 is washed with the pure water 25.

In addition, in order to calibrate the pH meter of the hydrogen ion index measuring means 4, a branch pipe 51 is connected to the pipe 31 near the reaction cell 3. In the branch pipe 51,
A pump 52 is interposed. On the upstream side of the pump 52, the branch line 51 branches into a pair of lines 53 and 54. A buffer solution 56 with a hydrogen ion index of 7, for example, is supplied to one pipe 53 via a calibration solution valve 55, and a buffer solution 58 with a hydrogen ion index of 9, for example, is supplied to the other pipeline 54 via a calibration solution valve 57. is supplied. Therefore, the pump 52 is driven, the calibration liquid valve 55 is opened, the calibration liquid valve 57 is closed, and the pipe line 5 is
A buffer solution 56 is sent to the reaction cell 3 via 1 and 31. This allows the PH meter to read, for example, PH7.
Calibrated to. Next, the calibration liquid valve 57 is opened, the calibration liquid valve 55 is closed, and the buffer solution 58 is sent to the reaction cell 3 through the pipes 51 and 31, so that the pH meter is calibrated to, for example, PH9.

In this way, absorbance can be measured in a short time without complicated operations, and since the hydrogen ion index is always constant, the amount of divalent copper ions can be determined correctly regardless of the composition of the plating solution 9. .

Although in the embodiments described above, a sulfuric acid acidic solution 5 was used, in other embodiments of the invention a basic solution such as a sodium hydroxide solution may be used.

In the above embodiment, the absorbance of divalent copper ions contained in the plating solution 9 was measured, but in other embodiments of the present invention, the absorbance is not limited to divalent copper ions, and the hydrogen ion index is measured. It may also be carried out in connection with a test liquid whose color changes as the color changes.

As described above, according to the present invention, accurate absorbance measurement can be performed regardless of the hydrogen ion index of the test solution.
Moreover, since the measurement can be carried out in a short time, periodic automatic measurement of absorbance is possible.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the prior art, and FIG. 2 is a system diagram showing the configuration of an embodiment of the present invention. 1... Automatic absorbance measurement device, 2... Collection means,
3... Reaction cell, 4... Hydrogen ion index measuring means, 5... Sulfuric acid acidic solution, 6... Adjustment means, 7...
... Absorbance measuring means, 9... Plating liquid, 10,2
3, 29, 30, 31, 42... pipe, 11, 3
4, 36, 43, 48... metering pump, 12...
Quantitative sampling device, 13... Supply pipe line, 14... Serpentine pipe section, 15, 24, 48, 52... Pump, 22,
47... Drain pipe, 26... Stirrer, 27... Glass electrode, 28... Temperature detector, 45... Absorbance cell, 46... Absorbance detection section.

Claims (1)

[Scope of utility model registration request] A collection means for collecting a certain amount of test solution from the solution to be measured, a reaction cell to which the test solution is supplied from the collection means, a hydrogen ion index measuring means provided in the reaction cell for measuring the hydrogen ion index, an adjusting means for adjusting the hydrogen ion index by dropping an acidic or basic solution according to the measured value of the ion index measuring means; and an absorbance for measuring the absorbance of the test solution whose hydrogen ion index has been adjusted in the reaction cell. 1. An automatic absorbance measuring device comprising: a measuring means.