JPH1150269A - Effective component measuring instrument for chemically dissolving liquid of copper or copper alloy and measuring method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously control the oxidizing agent concn. in a chemically dissolving liquid by continuously recognizing the concn. of an oxidizing agent (hydrogen peroxide in the case of a sulfuric acid + hydrogen peroxide system) of various kinds of the chemically dissolving liquid of copper or copper alloy. SOLUTION: The measuring instrument formed by electrically connecting an anode electrode 1 consisting of Cu or Cu alloy and a cathode electrode 2 consisting of a conductive material (Pt, Au, Ag, graphite, stainless steel) of the potential nobler than the potential of the anode electrode in the chemically dissolving liquid of the copper or copper alloy and installing an ammeter 4 therebetween is used. The anode electrode and the cathode electrode are immersed into the chemical dissolving liquid of the copper or copper alloy and the oxidizing agent concn. in the dissolving liquid is recognized with the current value (which indicates the value corresponding to the oxidizing agent concn.) flowing between both electrodes as a management index. The management of the oxidizing agent concn. in the chemical dissolving liquid is executed by properly feeding the oxidizing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for in-situ measurement of an active ingredient in a liquid when copper or a copper alloy is chemically dissolved.

[0002]

2. Description of the Related Art Copper and copper alloys have high electrical conductivity.
Widely used in the field of electronic materials. In the process of manufacturing these copper and copper alloy materials and the process of assembling electronic components, the surface is often subjected to a chemical dissolution treatment. For example, in a material manufacturing process, a chemical dissolution treatment such as chemical polishing or chemical etching may be performed to remove a thick oxide film generated by annealing or to remove polishing burrs after surface buffing or the like. In addition, in an electronic component assembling process, a chemical dissolution treatment such as chemical polishing or chemical etching may be performed as a surface adjustment before plating.

The chemical dissolving solution used here is sulfuric acid + hydrogen peroxide, sulfuric acid + peroxide, nitric acid, nitric acid + sulfuric acid,
Acids containing oxidizing agents such as nitric acid + phosphoric acid, sulfuric acid + hydrogen peroxide + fluoride, sulfuric acid + peroxide + fluoride, and additives such as surfactants and decomposition inhibitors as necessary Solution is used. When chemically dissolving copper and copper alloys, an oxidizing agent such as hydrogen peroxide or peroxide becomes an active ingredient, and therefore, the chemical dissolution rate changes depending on the concentration of these active ingredients, and these are contained. If not, copper hardly dissolves (however, nitric acid itself becomes an oxidizing agent).

[0004] Conventionally, as a method for quantifying and replenishing the effective component of the chemical solution of copper or copper alloy, a method of empirically replenishing the active component according to the treated area without particularly quantifying the effective component, A method of quantitatively sampling the liquid and quantitatively determining the active ingredient by instrumental analysis, and replenishing the liquid accordingly.
As in JP-A-2004474, a method has been devised in which an active ingredient is replenished using the immersion potential of a substance to be dissolved in a chemical solution or the same composition material as the substance to be dissolved as a control index.

[0005]

However, in the method of replenishing the active ingredient in accordance with the treatment area, it is difficult to make the replenishment continuous, so that it is difficult to keep the chemical dissolution rate constant, and therefore the chemical dissolution amount is also low. I don't know exactly. In the method of periodically sampling the liquid and quantifying and replenishing the active ingredient by instrumental analysis, the measured value of the active ingredient is accurate, but the analysis takes time, so a time lag always occurs from sampling to replenishment, and chemical dissolution occurs. It is difficult to keep the speed constant.
In the method disclosed in JP-A-6-240474, the active ingredient can be continuously replenished without causing a time lag. However, the stirring of the liquid or the immersion potential of the substance to be dissolved is used as a control index. In this case, there is a problem that the flow of the substance to be dissolved affects the measured value, and the application is limited to a case where a chemical dissolution solution of sulfuric acid + hydrogen peroxide is used.

Accordingly, the present invention is to continuously grasp the active ingredient concentration of various chemical solutions of copper or copper alloy, and to be able to continuously manage the active ingredient concentration in the chemical solution.
The purpose is to obtain a constant chemical dissolution rate.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various studies on the above-mentioned objects, and as a result, it has been found that one kind of Cu or Cu alloy is used as an anode electrode and a conductive material having a potential higher than that of the anode. When one kind of substance is used as a cathode electrode, these are electrically connected, and only the electrode portion is immersed in the chemical solution, the electric current flowing between the anode electrode and the cathode electrode is changed in the chemical solution. Was found to correspond to the concentration of the active ingredient. The present invention has been made based on this finding.

That is, the apparatus for measuring the effective component of a chemical solution of copper or a copper alloy according to the present invention comprises an anode electrode made of Cu or a Cu alloy, and a chemical solution of copper or a copper alloy that is higher than the anode electrode. A cathode electrode made of a conductive substance having a noble potential in a liquid is electrically connected, and an ammeter is provided between the cathode electrodes. Pt, C (graphite), Au, Ag, stainless steel, and the like can be given as examples of the conductive material constituting the cathode electrode. The distance between the anode and the cathode is preferably 2 mm to 10 m, and the area ratio between the anode and the cathode (the area of the anode / the area of the cathode) is preferably in the range of 0.0025 to 400.

The method for measuring the effective component of a chemical solution of copper or a copper alloy according to the present invention uses the above-described measuring apparatus in which an anode electrode and a cathode electrode are electrically connected and an ammeter is installed between the anode electrode and the cathode electrode. The electrode and the cathode electrode are immersed in a chemical solution of copper or a copper alloy, and the concentration of the active ingredient in the chemical solution is detected using the value of the current flowing therebetween as an index. According to this method, the concentration of the active ingredient in the chemical solution can be continuously managed, for example, by replenishing the active ingredient appropriately using the current value between the electrodes as a management index.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One type of Cu or Cu alloy is used as an anode electrode, and one type of conductive material having a higher potential than that is used as a cathode electrode. When immersed in a typical solution, a current flows between the anode electrode and the cathode electrode. The current flowing at this time is due to the potential difference between the anode electrode and the cathode electrode, which causes the anode electrode to gradually dissolve in the chemical dissolving solution and release electrons, and a reaction corresponding to the amount of electrons occurs on the cathode electrode surface. Occurs and the current value corresponds to the concentration of the active ingredient in the chemical lysis solution.

[0011] The reaction on the cathode electrode is consumed by the reduction of the active ingredient in the chemical solution. Therefore, the cathode electrode is Cu or Cu
It is sufficient that the potential is higher in the chemical solution than in the alloy. For example, Pt, C, Au, Ag, and stainless steel can be used. Note that the electrode itself only needs to be a predetermined conductive material in the liquid contact portion. For example, a conductive material obtained by plating a conductive material with Pt plating, Au plating, or Ag plating can be used as the cathode electrode.

It is not necessary that the cathode electrode and the anode electrode are always disposed close to each other, but if the distance is longer than 10 m, the value of the current flowing between the electrodes may fluctuate.
It is better to install at a distance of 0 m or less. If the distance is shorter than 2 mm, the liquid may stagnate between the electrodes,
2mm because the true value of the active ingredient may not be measured
It is better to separate them. If the area ratio (anode electrode area / cathode electrode area) of the liquid contact portion between the cathode electrode and the anode electrode is less than 0.0025 or more than 400, the current value may fluctuate.
25-400 is preferred.

In the present invention, Cu or C is used as the anode electrode.
Because u alloy is used, even if it is dissolved in copper or a chemical solution of copper alloy, it is contaminant, especially when the anode electrode is Cu or Cu alloy consisting of the same components as the copper alloy to be melted. Will not be. In addition, if there is no problem even if it dissolves in the liquid, Cu alloy containing different components and metals other than Cu or Cu alloy (for example, Zn, Fe,
Sn, Ni, alloys thereof, etc.) can be used as the anode electrode.

FIG. 1 shows an example of a measuring apparatus according to the present invention, in which an anode electrode 1 made of Cu or a Cu alloy is used.
And a cathode electrode 2 made of, for example, Pt having a higher potential than the cathode electrode 2 is electrically connected. An ammeter 4 is provided between the cathode electrode 2 and the signal of the ammeter 4 is supplied to the XY recorder 6 via the voltage converter 5. It is to be recorded. Reference numeral 3 denotes a fixing jig for fixing the electrodes, which is made of an insulating material. Further, it is also possible to connect an ammeter to a personal computer, link the active ingredient replenishing device through the personal computer, and perform the automatic operation thereof.

[0015]

Next, an example will be described in which the measurement device according to the present invention is used and the current value measured by the ammeter corresponds to the concentration of the active ingredient in the chemical solution. Copper alloy (Cu
-0.1Fe-0.03P) after melting and casting, hot rolling,
The copper alloy plate was manufactured by a manufacturing process on a mass production scale including cold rolling and annealing, and in a chemical etching process after annealing, a copper alloy plate was etched using a sulfuric acid-hydrogen peroxide-based etchant. At this time, only the anode electrode and the cathode electrode of the measuring apparatus shown in FIG. The anode electrode is oxygen-free copper (area:
2 cm ² ), the cathode electrode was composed of Pt (area: 1 cm ² ), and the distance L between both electrodes was 65 mm. At the same time, the concentration of hydrogen peroxide as an active ingredient was analyzed at any time by titration. These results are shown in FIG.

Referring to FIG. 2, the concentration of hydrogen peroxide in the etching solution is increased by the first replenishment of hydrogen peroxide, gradually decreased with time, and increased again by the second replenishment. And gradually declines over time. On the other hand, the current value of the measuring device shows a change just corresponding to the above change in the concentration of hydrogen peroxide analyzed as needed. As described above, since the current value of this measuring device corresponds to the hydrogen peroxide concentration, the hydrogen peroxide concentration in the etching solution can be measured using the current value as an index without analyzing the hydrogen peroxide concentration itself. The concentration of hydrogen peroxide in the etching solution can be controlled by, for example, replenishing hydrogen peroxide appropriately using the current value as a control index.

The current value of the measuring apparatus according to the present invention is not limited to the above sulfuric acid-hydrogen peroxide-based etchant, but may be any other chemical dissolution solution of copper or copper alloy. It corresponds to the concentration of the active ingredient (oxidizing agent) in it. Therefore, the concentration of the active ingredient in the chemical solution can be continuously grasped using the current value as an index, and the concentration of the active ingredient can be controlled using the current value as a control index.

[0018]

According to the present invention, the concentration of an active ingredient in a chemical solution of copper or a copper alloy is continuously grasped using a simple device and its current value is used as an index, and the concentration is continuously measured. Can be managed. Therefore, it is possible to keep the chemical dissolution rate of the substance to be dissolved within a certain range at all times. Further, there is an advantage that it can be widely applied to various chemical solutions of copper or copper alloy.

[Brief description of the drawings]

FIG. 1 is a schematic view of an active ingredient measuring device according to the present invention.

FIG. 2 is a graph showing the correspondence between the concentration of hydrogen peroxide in an etching solution and the current value of an effective component measuring device.

[Explanation of symbols]

 1 Anode electrode 2 Cathode electrode

Claims (5)

[Claims] An anode electrode made of Cu or a Cu alloy is electrically connected to a cathode electrode made of a conductive material having a potential higher in a solution of a chemical solution of copper or a copper alloy than the anode electrode. An active ingredient measuring device for a chemical solution of copper or a copper alloy, wherein an ammeter is installed in the meantime. 2. The conductive material constituting the cathode electrode is one selected from Pt, C (graphite), Au, Ag, and stainless steel.
An apparatus for measuring an effective component of a chemical solution of copper or a copper alloy described in the above item. 3. The method according to claim 1, wherein the distance between the anode electrode and the cathode electrode is 2 mm to 10 m, and the ratio of the anode electrode area to the cathode electrode area (anode electrode area / cathode electrode area) is 0.0025 to 400. 3. An apparatus for measuring an effective component of a chemical solution of copper or copper alloy according to claim 1 or 2. 4. An electrical connection is made between an anode electrode made of Cu or a Cu alloy and a cathode electrode made of a conductive substance having a higher potential in a solution of a chemical solution of copper or a copper alloy than the anode electrode. The anode and cathode electrodes are immersed in a chemical solution of copper or copper alloy using a measuring device with an ammeter between them, and the concentration of the active ingredient in the chemical solution is determined by using the current value flowing between them as an index. A method for measuring the effective component of a chemical solution of copper or a copper alloy, comprising measuring the content of copper. 5. An electrical connection is made between an anode electrode made of Cu or a Cu alloy and a cathode electrode made of a conductive substance having a potential higher in a solution of a chemical solution of copper or a copper alloy than the anode electrode. The anode and cathode electrodes are immersed in a chemical solution of copper or a copper alloy using a measuring device with an ammeter between them, and the current flowing between them is used as a control index to determine the effective components in the chemical solution. A method for controlling an effective component of a chemical solution of copper or a copper alloy, wherein the concentration is controlled.