JP2005146343A - Measuring method for concentration of additive, and plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily measure the concentration of a nitrogen-containing additive in a plating liquid with high precision without previously measuring the concentration of the other additive, particularly, to perform the measurement and/control in the concentration of a nitrogen-containing additive in a plating liquid so as to impart satisfactory filling properties in damascene and via filling. <P>SOLUTION: Regarding the method, in a plating liquid comprising a sulfur based additive and/or a high polymer based additive and a nitrogen-containing additive, the concentration of the nitrogen-containing additive is measured by cyclic voltammetry without measuring the concentration of the sulfur based additive and/or high polymer additive. In this case, regarding the plating standard liquid containing the additive in a known concentration, a rotary electrode is rotated at different two rotating speeds to obtain measured values, a calibration curve is prepared by the difference in the characteristics values and/or ratios in the measured values and the concentration of the additive in the plating standard liquid to obtain a characteristic value regarding the plating liquid in which the concentration of the additive is unknown, and the concentration of the additive in the plating liquid is decided from the characteristic value of the plating liquid with the calibration curve as the standard. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for measuring the concentration of an additive in a plating solution, and more particularly to a method for measuring the concentration of a nitrogen-containing compound-based additive in a plating solution containing a plurality of additives by cyclic voltammetry. The present invention also relates to a plating method suitable for forming a metal wiring by filling a plating on a concave portion on a substrate surface such as via filling.

  Various additives are contained in the copper sulfate plating solution used for damascene, via filling, etc. at the time of semiconductor manufacture. In these plating solutions, the concentration control of the additive is regarded as important. Additives contained in such plating solutions are roughly classified into three types. That is, a suppressor made of a high molecular compound (also called a polymer, a wetter or a carrier), a brightener made of a sulfur compound (also called an accelerator or an additive), and a nitrogen-containing compound (particularly, a quaternary which becomes a cation in a solution) Three kinds of levelers made of an ammonium compound). Among these additives, Brightner has a plating accelerating action, and suppressors and levelers have a plating inhibiting action. Therefore, using this difference in action, CVS (Cyclic) is a kind of cyclic voltammetry method. There has been proposed a method for measuring an additive concentration by a Voltammetry Stripping method.

  In the CVS method, the working electrode (rotating electrode), reference electrode, and counter electrode are immersed in a measurement solution containing an additive, and the rotating electrode (generally a Pt electrode) is rotated at an arbitrary constant speed while the potential is set between a predetermined potential. From the voltammogram showing the change in the current value shown when the plating film is deposited on the rotating electrode by sweeping at a predetermined speed and peeled (dissolved), the peel peak area Ar (Area Rotating) It is known as a method of obtaining a value and making this a value corresponding to the additive concentration, and determining the concentration based on a calibration curve measured in advance by a similar method (Non-patent Document 1: “Surface Technology”, No. 54). Vol. 4, No. 4, pp. 278-280). In the measurement solution, the Ar value increases as the additive having the plating promoting action increases, and the Ar value decreases as the additive having the plating inhibiting action increases.

  The additive concentration measurement using the CVS method is based on this principle. The Ar value measured by the plating accelerating action is the value corresponding to the Brightener concentration, and the Ar value measured by the plating inhibiting action is used. The concentration can be determined as a value corresponding to the suppressor and leveler concentrations. In the actual measurement of the plating solution, only the concentration of a specific additive is measured without being influenced by additives other than the additive to be measured.

  In this case, since the leveler concentration is considerably lower than the suppressor concentration, the value measured by the plating suppression action is generally handled as a value corresponding to the suppressor concentration for convenience. Accordingly, it is possible to measure the Brightner concentration and the suppressor concentration by setting the Ar value measured by the plating accelerating action as a value corresponding to the Brightner concentration and the Ar value measured by the plating inhibiting action as a value corresponding to the suppressor concentration.

  Here, the problem is the leveler concentration. Since the leveler has a low concentration and a low response, the Ar value is small, and it is greatly affected by the brightener and suppressor. In other words, the measured Ar value is a value obtained as a result of interference between the brightening, suppressor, and leveler plating accelerating action and plating suppressing action, so even if the leveler concentration in the measurement liquid is the same, the brightener When the concentration and the suppressor concentration are different, the obtained Ar value changes greatly. For this reason, it has been difficult to measure the leveler concentration with high accuracy by cyclic voltammetry. On the other hand, as a method for measuring the leveler concentration without being influenced by the concentration of these brighteners and suppressors, Japanese Patent Publication No. 60-19455 (Patent Document 1) and Japanese Patent Publication No. 8-20417 (Patent Document 2). ), Japanese Patent No. 3130112 (Patent Document 3), Japanese Patent Application Laid-Open No. 2002-195983 (Patent Document 4), Japanese Patent Application Laid-Open No. 2001-73183 (Patent Document 5), and a cyclic voltammetry CV (Cyclic Voltammetry). ) Method, CPV (Cyclic Pulse Voltammetry) method, CVS method, and CPVS (Cyclic Pulse Voltammetry Stripping) method. However, these methods require the creation of a calibration curve formula for determining the Brightner concentration and suppressor concentration.Besides measuring the leveler concentration, the Brightner concentration and suppressor concentration are determined in advance. It has to be kept and the work is complicated.

  “Surface Technology”, Vol. 54, No. 4, p. In 278-280 (Non-Patent Document 1), as a method that does not require measurement of Brightner concentration or suppressor concentration, there is an RC method that eliminates the influence of these two components using a solution saturated with Brightner or suppressor. It has been introduced. However, this method requires time and effort for the saturation treatment, and depending on the type of additive, additives other than the leveler, i.e., both the suppressor and the brightener may not be saturated. Cannot measure the leveler concentration.

  By the way, as a method for forming a metal wiring on a printed circuit board or a wafer substrate, a method of filling copper plating into recesses such as via holes and trenches formed on the substrate surface, such as damascene and via filling, is employed. When using copper plating solution such as copper sulfate plating solution in damascene or via filling, if the via filling is taken as an example, the leveler hardly acts on the thick diffusion layer such as the bottom of the via inside the via hole. Thus, the plating accelerator acts predominately to promote the plating, and the leveler acts on the thin diffusion layer such as the outside of the via hole. Therefore, the plating inhibitor acts predominately to suppress the plating. Via holes can be filled efficiently by the action of this leveler (see Non-Patent Document 2). This is because there is a difference in the progress of plating between the thick diffusion layer and the thin diffusion layer due to the presence of the leveler. It means to occur. For this reason, the leveler concentration management in the copper plating solution is important. However, even when the leveler concentration is controlled using the above-described measurement method, there may be a case where stable hole filling properties cannot be obtained stably.

  In addition, the use of an additive having a plating accelerating action or a plating inhibitory action is also carried out in a plating solution other than a copper plating solution, and the same operation can be performed when measuring this plating solution by cyclic voltammetry. It may be complicated or it may be difficult to specify the additive concentration with high accuracy.

Japanese Patent Publication No. 60-19455 Japanese Patent Publication No. 8-20417 Japanese Patent No. 3130112 JP 2002-195983 A JP 2001-73183 A Hideto Otani, “Analysis of Electrolytic Copper Plating Solution Using CVS Analyzer”, Surface Technology, Surface Technology Association of Japan, 2003, Vol. 54, No. 4, p. 278-280 Takufumi Matsunami, 3 others, “Culphate plating additive for via filling”, METEC 2003 (10th Microelectronics Symposium) Proceedings, Japan Institute of Electronics Packaging, 2000, p39-42

  The present invention has been made in order to solve the above-mentioned problems, and has an additive concentration, particularly an additive concentration such as a nitrogen-containing compound-based additive in a plating solution having a plurality of additives. Another object of the present invention is to provide a method for measuring the concentration of a leveler contained in a copper plating solution such as a copper sulfate electroplating solution used for via filling or the like with high accuracy by cyclic voltammetry. It is another object of the present invention to provide a plating method capable of stably filling a plating when filling a concave portion on a substrate surface such as via filling to form a metal wiring.

  In the present invention, when measuring the leveler concentration in a copper sulfate plating solution by cyclic voltammetry, the leveler-containing plating standard solution having a known concentration is measured by rotating the rotating electrode at two different rotation speeds α and β. The basic idea is that the values a and b are obtained, the difference between the measured values a and b is used as a characteristic value for the leveler concentration, and the relational expression between the characteristic value and the leveler concentration is used as a calibration curve.

  The measured value (the amount of electricity, the peak value of the current amount or the plating amount) measured by the cyclic voltammetry method is the value obtained as a result of the interference of the plating promoting action and the plating inhibiting action of the brightener, suppressor and leveler ( Brighter action + suppressor action + leveler action), of which the action of the brightener and suppressor is constant regardless of the rotational speed. From this, the present inventor measured the measured value by changing the number of rotations of the rotating electrode, and a value obtained by using the difference in the effect of the leveler on the plating progress derived therefrom, that is, at two different numbers of rotations. It was considered that the leveler concentration can be measured by using the difference between the measured values as the characteristic value, eliminating the influence of the action of the brightener and the suppressor.

  In addition, when plating in damascene or via filling, it is particularly important to balance the progress of plating at the bottom of the via and the progress of plating on the substrate surface, and the leveler concentration in the plating solution can achieve this balance of the progress of plating. Have been adjusted so that. For example, if the leveler concentration in the plating solution is lower than the initially set concentration, even if the progress of plating at the bottom of the via where the leveler action is small does not change, the plating progress on the substrate surface where the leveler action is large is fast. As a result, the progress of plating around the opening of the via hole is accelerated, and as a result, voids or the like are generated, and there is a possibility that satisfactory filling cannot be performed. Thus, in the plating solution used for damascene or via filling, it is important to adjust the leveler concentration so that the action of the leveler on the via bottom and the substrate surface is balanced. By the way, in the cyclic voltammetry method, it is possible to adjust the thickness of the diffusion layer on the electrode surface by changing the rotation speed of the rotating electrode. If the rotation is high, the diffusion layer is thin (the effect of the leveler is large). If the rotation is low, the diffusion layer becomes thick (a pseudo state where the action of the leveler is small). That is, if the rotation is high, a pseudo state of the progress of plating on the surface of the substrate can be created, and if the rotation is low, a pseudo state of the progress of plating on the bottom of the via can be created. Therefore, the present inventor uses the ratio obtained by dividing the measured value at the high rotation and the measured value at the low rotation by the measured value at the high rotation, thereby proceeding the plating on the surface of the substrate (the effect of the leveler). 1 can be used as a relative value for the plating progress (leveler effect) at the bottom of the via, and by measuring the leveler concentration in the plating solution using the difference in the ratio as a characteristic value, Based on the relationship between the level of plating and the balance of plating progress between via holes and trenches, the leveler concentration can be measured and managed with high accuracy.

  Based on the above idea, the present inventor plated the characteristic value using the difference in the measured value (the amount of electricity, the peak value of the current amount or the plating amount) when the rotational speed of the rotating electrode is changed in the cyclic voltammetry method. Cyclic voltammetry is the result of extensive research, considering that the concentration of additives in the plating solution can be measured easily and with high accuracy by using it as a calibration curve for determining the concentration of additives in the solution. , Measured values a and b (measured values A and B) respectively measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at two different rotational speeds α and β. The characteristic value of the additive is used as a characteristic value of the additive, the characteristic value is obtained for a plating standard solution containing the additive at a known concentration, and a calibration curve is obtained by the characteristic value and the additive concentration that gives the characteristic value. make The characteristic value of the plating solution whose additive concentration is unknown is obtained, and the concentration of the nitrogen-containing additive in the plating solution is determined with high accuracy based on the calibration curve from the characteristic value of the plating solution whose additive concentration is unknown. It was found that the measurement can be performed easily.

  Further, the measured values a and b (measured values A and B) measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at two different rotational speeds α and β. If the value using the difference in ratio to a (measured value A) or measured value b (measured value B) is the above characteristic value, particularly in damascene and via filling, good fillability can be given. It has been found that the additive concentration in the plating solution can be measured and managed, and the present invention has been made.

That is, the present invention provides the following additive concentration measuring method and plating method.
Claim 1:
The concentration of the nitrogen-containing additive in the plating solution containing the sulfur-based additive and / or the polymer-based additive and the nitrogen-containing additive without measuring the concentration of the sulfur-based additive and the polymer additive. Is measured by cyclic voltammetry,
For each of one or more plating standard solutions containing the additive at a known concentration, the measured values a and b are determined by rotating the rotating electrode at two different rotational speeds α and β,
Create a calibration curve by the characteristic value using the difference and / or ratio of the measured values a and b and the additive concentration of the plating standard solution,
Determination of the additive concentration of the plating solution, wherein the characteristic value is determined for the plating solution having an unknown additive concentration, and the additive concentration of the plating solution is determined based on the calibration curve from the characteristic value of the plating solution. Method.
Claim 2:
The characteristic values are the following (I) to (VI)
(I) Measured value a (Measured value A) −Measured value b (Measured value B)
(II) Measured value b (Measured value B) −Measured value a (Measured value A)
(III) 1-Measured value a (Measured value A) / Measured value b (Measured value B)
(IV) 1-Measured value b (Measured value B) / Measured value a (Measured value A)
(V) Measured value a (Measured value A) / Measured value b (Measured value B) -1
(VI) Measured value b (Measured value B) / Measured value a (Measured value A) -1
The additive concentration measuring method according to claim 1, wherein the value is obtained using any one of the following.
Claim 3:
The method for measuring an additive concentration according to claim 1 or 2, wherein the plating solution is a copper plating solution containing a leveler as the nitrogen-containing additive.
Claim 4:
A plating solution in which the concentration is determined by measuring the additive concentration by the method for measuring an additive concentration according to any one of claims 1 to 3 is used to fill holes or grooves in the substrate with plating. Plating method.

The present invention eliminates the effects of sulfur-based additives and polymer-based additives that affect the progress of plating by using the difference in values measured by changing the number of rotations of the rotating electrode, and contains nitrogen. Is to measure the concentration of additives,
[1] It has the feature of being hardly affected by other additives, and the additive containing nitrogen in the plating solution, particularly the leveler concentration in the copper sulfate plating solution, with high accuracy and other additives. The concentration can be easily measured without measuring in advance.

In addition, the present invention contains nitrogen by utilizing the difference in the promotion / suppression effect of the plating progress of the additive containing nitrogen due to the difference in the thickness of the plating diffusion layer caused by changing the rotation speed of the rotating electrode. Is to measure the additive concentration,
[2] It has a feature that a measurement result reflecting the hole filling property in actual plating can be obtained, and nitrogen in the plating solution can be provided particularly in damascene, via filling, etc. It is possible to measure and manage the concentration of additives containing.

The present invention will be described in detail below.
The method for measuring the concentration of the additive according to the present invention is the method of measuring the concentration of the sulfur additive and the polymer additive in a plating solution containing a sulfur additive and / or a polymer additive and a nitrogen-containing additive. A method of measuring the concentration of the nitrogen-containing additive by cyclic voltammetry without measuring the rotating electrode for each of one or more plating standard solutions containing the additive at a known concentration. Measured values a and b are obtained by rotating at different two rotational speeds α and β, respectively, and calibration is performed based on the characteristic value using the difference and / or ratio between the measured values a and b and the additive concentration of the plating standard solution. A line is prepared, the characteristic value is determined for the plating solution whose additive concentration is unknown, and the additive concentration of the plating solution is determined from the characteristic value of the plating solution with reference to the calibration curve.

  More specifically, between a rotating electrode and a counter electrode immersed in a plating solution containing a sulfur-based additive and / or a polymer-based additive and an additive containing nitrogen (nitrogen-containing additive). Addition of the above sulfur-based additive and polymer system by cyclic voltammetry to deposit plating on the rotating electrode by sweeping the voltage while rotating the rotating electrode, or to dissolve and peel the plating deposited on the rotating electrode. It is a method of measuring the concentration of nitrogen-containing additive in the plating solution without measuring the concentration of the agent, and preparing one or more plating standard solutions containing the nitrogen-containing additive at a known concentration, Measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at different two rotation speeds, when plating is deposited on the rotating electrode or on the rotating electrode. A value using the peak value of the amount of electricity or current required to dissolve and peel the deposited plating or the difference and / or ratio of the amount of plating deposited on the rotating electrode is the characteristic value of the nitrogen-containing additive, and the plating Obtain the above characteristic value for the standard solution, create a calibration curve with this characteristic value and the concentration of the nitrogen-containing additive that gives it, determine the above characteristic value for the plating solution whose nitrogen-containing additive concentration is unknown, The concentration of the nitrogen-containing additive in the plating solution is determined based on the above calibration curve from the characteristic value of the plating solution whose additive concentration is unknown.

  In the present invention, the plating solution contains a nitrogen-containing additive. In particular, it contains a sulfur-based additive and / or a polymer-based additive and a nitrogen-containing additive. Here, the sulfur-based additive, polymer-based additive, and nitrogen-containing additive are used for plating solution basic composition components (water-soluble metal salt, base acid, complexing agent), pH adjustment and pH buffering. In addition to the additive to be added, the additive is added to improve the film properties of the deposited plating film, which is a sulfur compound, a polymer compound, or a nitrogen-containing compound. For example, in a copper sulfate plating solution, a bright additive is used as a sulfur additive, a suppressor is used as a polymer additive, and a leveler is used as a nitrogen-containing compound. In the nickel plating solution, the sulfur-based additive and the polymer additive include primary or secondary brighteners, and the nitrogen-containing additive includes the above primary or secondary brighteners, and various coating films. Examples include quaternary ammonium salts added to obtain characteristics. These sulfur-based additives, polymer-based additives, and nitrogen-containing additives have an action of promoting or suppressing plating deposition, and the present invention determines the concentration of nitrogen-containing additives using cyclic voltammetry. In particular, the effects of sulfur-based additives and polymer-based additives are affected, and this is particularly effective for plating solutions in which the nitrogen-containing additive concentration cannot be accurately measured by conventional methods.

  The nitrogen-containing additive is a compound containing nitrogen as a constituent element, and other than the above basic composition components, and is not particularly limited as long as it is added mainly for purposes other than pH adjustment and pH buffering. In the conventional method by cyclic voltammetry, the measured value largely fluctuates, for example, a quaternary ammonium salt.

  In the cyclic voltammetry used in the present invention, plating is deposited on the rotating electrode by sweeping the voltage while rotating the rotating electrode between the rotating electrode immersed in the plating solution and the counter electrode, or this rotating electrode. This is a technique for dissolving and peeling the plating deposited on the surface, and measuring the amount of electricity and current required (generated) at this time to evaluate the deposition / dissolution peeling behavior of the plating solution.

  For cyclic voltammetry, the CV (Cyclic Voltammetry) method for only the plating deposition region, CVS (Cyclic Voltammetry Stripping) for the plating stripping region and / or the plating stripping region. There are methods, and any of these methods can be adopted in the present invention. Further, a CPV (Cyclic Pulse Voltammetry) method and a CPVS (Cyclic Pulse Voltammetry Stripping) method of measuring the voltage by pulse sweeping are also possible.

  In the present invention, in order to measure the nitrogen-containing additive concentration in the plating solution, the characteristic value (k) relating to the nitrogen-containing additive concentration is used. This characteristic value (k) is derived from cyclic voltammetry based on various measured values measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at a predetermined number of rotations. It is a value representing the effect of the progress of plating, specifically, the peak value of the amount of electricity or current required when depositing the plating on the rotating electrode or dissolving and peeling the plating deposited on the rotating electrode, or After measuring the amount of plating deposited on the rotating electrode at two different rotational speeds α and β, the effect of the nitrogen-containing additive on the progress of plating at the above-mentioned two rotational speeds α and β (high and low rotational speeds) It is a value representing the difference between

In the present invention, as such a characteristic value,
[1] Respective measured values a and b (measured values A and B) measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at two different rotational speeds α and β. Or a value obtained by adding / subtracting / dividing by an arbitrary number or mathematical expression, or [2] When the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at two different rotation speeds α and β Or the difference in the ratio of each measured value a and b (measured value A and B) to measured value a (measured value A) or measured value b (measured value B), or any number or formula The value obtained by adding / subtracting / dividing with can be applied.

The above characteristic values are obtained for both the plating standard solution and the plating solution whose nitrogen-containing additive concentration is unknown. Specifically, when the plating standard solution is measured by cyclic voltammetry, a measurement value a at the rotation number α of the rotating electrode and a measurement value b at the rotation number β are obtained, and from these measurement values a and b, [1] Difference between measured value a and measured value b,
[2] Difference in ratio of the measured value a and the measured value b to the measured value a or the measured value b,
[3] A value using the above [1] and [2] as an index is obtained, and this obtained value is used as a characteristic value of the additive concentration of the plating standard solution. Similarly, when measuring the plating solution whose nitrogen-containing additive concentration is unknown by cyclic voltammetry, the measured values A and B at the same rotation electrode rotation speeds α and β as in the case of the plating standard solution are obtained. From the measured values A and B, [1 ′] the difference between the measured value A and the measured value B,
[2 ′] A difference in ratio of the measured value A and the measured value B to the measured value A or the measured value B,
[3 ′] A value using [1 ′] and [2 ′] as an index is obtained, and the obtained value is used as a characteristic value of the additive concentration of the plating solution.

  Here, the characteristic value of the plating standard solution is any one of the above [1] to [3]. [1] The difference between the measured value a and the measured value b is the following formula (1) or (2 ). This formula (1) or (2) eliminates the influence of the sulfur-based additive and the polymer-based additive as described above, without measuring the concentration of the sulfur-based additive and the polymer-based additive in advance, It is intended to measure the concentration of nitrogen-containing additives.

Measured value a-measured value b (1)
Measured value b-measured value a (2)

  [2] The difference in the ratio of the measurement value a and the measurement value b to the measurement value a or the measurement value b refers to a value represented by any one of (3) to (6) below. Equations (3) to (6) are obtained by using ratios such as measurement value a / measurement value a, measurement value b / measurement value a, measurement value a / measurement value b, measurement value b / measurement value b. It is intended to estimate the concentration of nitrogen-containing additive based on the relative comparison of plating progress inside and outside trenches and via holes in damascene and via filling. Furthermore, by utilizing the difference in the ratio, the plating progress of the nitrogen-containing additive can be performed without measuring the concentrations of the sulfur-based additive and the polymer-based additive in advance as in the above formulas (1) and (2). The concentration of the nitrogen-containing additive is to be estimated from the relationship between the effect on the concentration and the concentration of the nitrogen-containing additive. For example, in the following formula (3), when the rotational speeds α and β when the measurement values a and b are measured are α> β, the plating progress outside the via hole is set to 1, and the relative difference in the plating progress from the inside of the via hole is 1 As an action of the nitrogen-containing additive. Therefore, in the case of α <β, the following formulas (4) to (6) can also be used depending on combinations such as the case where the plating progress inside the via hole is set to 1 and the relative difference in plating progress from the outside of the via hole is seen.

1-Measured value b / Measured value a (3)
1-Measured value a / Measured value b (4)
Measurement value b / measurement value a-1 (5)
Measured value a / Measured value b-1 (6)

  [3] The values using [1] and [2] as indexes are values obtained by adding, subtracting, and dividing the values of [1] and [2] by an arbitrary number or mathematical expression. This means that a value obtained by appropriately adding, subtracting, and dividing the values obtained from the formulas (1) to (6) is set as the characteristic value within a range not detracting from the intention of the formulas [1] to [6]. In addition, there is no particular limitation when there is one type of plating standard solution, but when there are two or more types of plating standard solutions, the same number or the same mathematical expression is used for all the plating standard solutions, and the same addition, subtraction, multiplication and division are performed. is there.

The characteristic value of the plating solution in which the nitrogen-containing additive is unknown is any one of the above [1 ′] to [3 ′], and the difference between the above [1 ′] measured value A and measured value B is as follows. The value represented by the formula (1 ′) or (2 ′).
Measured value A-measured value B (1 ')
Measured value B-measured value A (2 ')

[2 ′] The difference in the ratio of the measured value A and the measured value B to either the measured value A or the measured value B refers to a value represented by any of the following (3 ′) to (6 ′). .
1-Measured value B / Measured value A (3 ')
1-Measured value A / Measured value B (4 ')
Measurement value B / measurement value A-1 (5 ')
Measured value A / Measured value B-1 (6 ′)

  [3 '] The value using [1'] and [2 '] as an index means a value obtained by adding, subtracting, and dividing the values of [1'] and [2 '] by an arbitrary number or mathematical expression. Here, the arbitrary number means the same number as the arbitrary number used when determining the characteristic value of the plating standard solution, and the arbitrary numerical expression is an arbitrary numerical expression used when determining the characteristic value of the plating standard solution Means the same formula. Further, “addition / subtraction / division” means performing the same addition / subtraction / division as the addition / subtraction / division used in the plating standard solution.

  As specific examples, the measured values at two different rotation speeds (high rotation speed and low rotation speed) are used, and the above equations (1) to (6) (the above equations (1 ′) to (6 ′)). The value obtained by substituting it into an equation using any one of () is the characteristic value (k). The formula for calculating the characteristic value (k) (expression expressing the difference in the effect on the plating progress by the nitrogen-containing additive) is the effect of the effect on the plating progress by the nitrogen-containing additive based on the measured values measured at the different rotational speeds. There is no particular limitation as long as the difference is utilized, and it can be appropriately determined according to the plating solution to be measured. For example, when the value of [1] ([1 ′] is a characteristic value, the following equation (7), and when the value of [2] ([2 ′]) is a characteristic value, the following equation (8) When the value of [3] ([3 ′]) is used as a characteristic value, an equation such as the following equation (9) can be given.

k = Av ₁ −Av ₂ (7)
k = (Av ₁ −Av ₂ ) / Av ₂ (8)
_{k = (1-Av 1 /} Av 2) / (R 2 -R 1) ... (9)
(In the formula, Av ₁ and Av ₂ were deposited on the rotating electrode or the peak value of the amount of electricity or current required for depositing the plating on the rotating electrode or dissolving and peeling the plating deposited on the rotating electrode. The amount of plating, Av ₁ is the value with the smaller number of revolutions, Av ₂ is the value with the larger number of revolutions, R ₁ is the number of revolutions with the smaller number of revolutions, and R ₂ is the number of revolutions. ).

  Thus, by using the above characteristic values, it is possible to determine the concentration of the nitrogen-containing additive while eliminating the influence of sulfur-based additives and polymer-based additives such as brighteners and suppressors in the copper plating solution. The concentration of the nitrogen-containing additive can be determined without measuring the concentration of the sulfur-based additive or the polymer-based additive. Furthermore, since the concentration of the nitrogen-containing additive can be determined by the difference in the effect of the nitrogen-containing additive on the plating progress, if the nitrogen-containing additive concentration is measured by this method, good filling in damascene and via filling is possible. It is possible to prepare a plating solution capable of stably obtaining the properties.

  Here, when the plating is deposited on the rotating electrode or when the plating deposited on the rotating electrode is dissolved and peeled, the electric quantity required is the peak area of the voltammogram indicating the change in the amount of current measured by cyclic voltammetry. The peak value of the current amount is the peak value (maximum value or minimum value) of the electric quantity indicated by the voltammogram. The plating amount deposited on the rotating electrode is the mass of the plating deposited on the rotating electrode by cyclic voltammetry.

  In the case of a measurement method that targets both the plating deposition region and the plating peeling region, such as the CVS method and the CPVS method, the amount of electricity, the peak value of the current amount, or the amount of plating in both regions is targeted. On the other hand, in the case of a measurement method that targets only the plating deposition region, such as the CV method or the CPV method, only the electric amount, the peak value of the current amount, or the plating amount of the plating deposition region is targeted.

Next, a method for measuring the nitrogen-containing additive concentration of a plating solution whose nitrogen-containing additive concentration is unknown using this characteristic value will be described.
As an apparatus used in the method of the present invention, a conventionally known apparatus commercially available as a cyclic voltammetry measuring apparatus can be used.

  In the present invention, in order to determine the nitrogen-containing additive concentration of the plating solution whose nitrogen-containing additive concentration is unknown, first, a calibration curve is created. This calibration curve is prepared by preparing one or more plating standard solutions containing a nitrogen-containing additive at a known concentration, obtaining the above characteristic values for this plating standard solution, and giving this characteristic value and nitrogen-containing addition A calibration curve is created according to the agent concentration. Next, a characteristic value is obtained for the plating solution whose nitrogen additive concentration is unknown, and the additive concentration in the plating solution is determined based on the calibration curve from this characteristic value.

  The plating standard solution only needs to contain at least a nitrogen-containing additive at a known concentration. Usually, components other than the nitrogen-containing additive are also known concentrations, and the concentration of the nitrogen-containing additive is unknown. It is preferable to have the same composition and concentration as the plating solution (hereinafter sometimes abbreviated as the test plating solution). For example, when the test plating solution is a copper sulfate plating solution containing copper sulfate, sulfuric acid, hydrochloric acid, brightener (sulfur-based additive), suppressor (polymer-based additive), and leveler (nitrogen-containing additive) It is preferable to use a plating standard solution containing components other than the leveler in the same composition and concentration as the test plating solution. By doing so, the leveler (nitrogen-containing additive) concentration can be measured with high accuracy. In the method of the present invention, since it is possible to measure without the influence of the action of a sulfur-based additive such as Brightner or a polymer-based additive such as a suppressor, other than the nitrogen-containing additive in the plating standard solution Even if the composition and concentration of the components are not the same as the plating solution to be tested, and when multiple plating standard solutions are used, the composition and concentration of the components other than the nitrogen-containing additive in each plating standard solution must be the same. However, the concentration of the test plating solution can be measured sufficiently.

  As a specific example of measurement, copper sulfate, sulfuric acid, hydrochloric acid, brightener, suppressor, and a plating solution containing a leveler that is a nitrogen-containing additive are used as the test plating solution. A plating standard solution A is prepared in which a toner and a suppressor are contained at the same concentration as the test plating solution, and a leveler is contained at an arbitrary concentration. For this plating standard solution A, Ar (exfoliation peak Area (electric quantity)) is measured and the measured value is substituted into the above equation (8) to obtain the characteristic value. Next, a plating standard solution B that differs only in the leveler concentration from the plating standard solution A is prepared, and each Ar is measured at the same rotational speed as that measured for the plating standard solution A, and the measured values are similarly expressed by the above formula (8 ) To obtain the characteristic value. Furthermore, if necessary, a standard plating solution C, D,... Whose leveler concentration is different from other plating standard solutions is prepared, and the characteristic values are obtained in the same manner. From the respective characteristic values and leveler concentrations of the obtained plating standard solutions A, B, C, D,..., A calibration curve is obtained by calculating a relational expression between these characteristic values and the leveler concentration by a method as described later. And At this time, as a leveler concentration (nitrogen-containing additive concentration) of the plating standard solution to be prepared, at least from the viewpoint of preventing trouble when actually plating using the test plating solution, at least the test plating solution It is preferable to select three concentrations: a concentration within the nitrogen-containing additive management concentration range, a concentration exceeding the range, and a concentration below the range when actually performing plating using Pt.

  When measuring the plating standard solution by cyclic voltammetry, in order to measure with higher accuracy, it is preferable to measure at a low rotation first and then at a high rotation. This is because the sulfur-based additive in the plating standard solution may be adsorbed on the surface of the rotating electrode and the measurement accuracy may deteriorate. Alternatively, the measurement may be carried out after diluting the plating standard solution or saturating the brightener or suppressor. When using the CV method or the CPV method, it is preferable to measure the following plating standard solution after measuring the plating standard solution and then peeling the plating on the electrode and washing the electrode. Furthermore, it is preferable to measure at the standard plating temperature when actually plating.

  Next, a calibration curve is prepared by the characteristic value obtained by the above method and the concentration of the nitrogen-containing additive that gives the characteristic value. The characteristic value of one plating standard solution having a known nitrogen-containing additive concentration is obtained, and the calibration is performed. The linear equation can be a linear function passing through the origin, but in order to obtain a higher accuracy calibration curve equation, two or more, preferably about 3 to 5 types of nitrogen containing different nitrogen-containing additive concentrations are contained. Characteristic values are determined using plating standard solutions with known additive concentrations, and a calibration curve formula between the characteristic values and the nitrogen-containing additive concentration that gives this characteristic value is first-order by regression calculation using the least squares method. It is preferable to determine by approximating a function, a quadratic function, or the like. In particular, the characteristic values are obtained using a plating standard solution having a known concentration of 3 or more, preferably 3 to 5 nitrogen-containing additives having different nitrogen-containing additive concentrations. It is preferable to determine a calibration curve equation between the nitrogen-containing additive concentrations that gives an approximation to a quadratic function by regression calculation using the method of least squares. In this case, the nitrogen-containing additive concentration used together with the characteristic value to obtain the calibration curve is how much more or less than a certain reference concentration, even if the actual concentration of the nitrogen-containing additive in the plating standard solution is used. May be used.

  Further, the rotational speeds α and β when rotating the rotating electrode are not particularly limited, but from 200 to 3000 rpm, particularly from 500 to 2500 rpm, depending on the type and concentration of each component in the plating solution, Furthermore, assuming the aspect ratio of via holes and trenches when actually used with a plating solution, the number of rotations can be appropriately selected and measured.

  Finally, the nitrogen-containing additive concentration of the plating solution whose nitrogen-containing additive concentration is unknown is the same as the plating standard solution, the above characteristic values are obtained for the plating solution whose nitrogen-containing additive concentration is unknown, and the method described above Substituting the characteristic value of the plating solution whose nitrogen-containing additive concentration is unknown into the calibration curve equation determined by (1) can be obtained. At this time, when the plating solution whose nitrogen-containing additive concentration is unknown is measured by cyclic voltammetry, the rotation speed of the rotating electrode for obtaining the measurement value A and the measurement value B is the same as that for measuring the plating standard solution. Let α and β be. Further, when the characteristic value k) is obtained using an equation corresponding to the equation used in the plating standard solution (for example, when the characteristic value of the plating standard solution is obtained by the above equation (3), the above equation (3) Using '), determine the characteristic value of the plating solution whose nitrogen-containing additive concentration is unknown. Furthermore, the measurement conditions such as the solution temperature at the time of measurement are preferably the same as the plating standard solution.

  The measurement method of the present invention includes, for example, a quaternary ammonium compound that becomes a cation in a solution called a leveler, which is added in a trace amount to a copper plating solution containing a copper salt such as copper sulfate, an inorganic acid such as sulfuric acid, and a chloride ion. It is suitable for measuring the concentration of nitrogen-containing additives such as In particular, it is suitable for measuring the concentration of a leveler in a copper plating solution containing a sulfur-based additive called brightener and / or a polymeric additive called suppressor together with the leveler in the copper plating solution.

  A plating method using a plating solution in which the concentration of a nitrogen-containing additive is adjusted by the measurement method of the present invention is suitable as a method for forming a metal wiring by filling a plating on a concave portion of a substrate surface such as damascene or via filling. . In this case, the nitrogen-containing additive concentration is measured by the measurement method described above, and the nitrogen-containing additive concentration in the plating solution is adjusted to a concentration specified in advance in the actual plating based on the measured value, and then the adjustment is performed. What is necessary is just to plate by immersing a base material in the subsequent plating solution. In particular, a copper plating solution containing a brightener and / or a suppressor and a leveler has a plating accelerator acting preferentially because the leveler hardly acts in a thick diffusion layer such as the inside of a via hole. This is characterized in that the plating is suppressed by the action of the leveler in a portion where the diffusion layer is thin like the outside of the via hole. Therefore, in this case, if the number of revolutions is appropriately adjusted in the cyclic voltammetry used in the measurement method of the present invention, the amount of electricity, the peak value of the current amount, or the value of the plating amount measured when the rotating electrode is rotated at a high speed can be obtained. The value corresponding to the thin state of the diffusion layer, such as the outside of the via hole, and the amount of electricity, the peak value of the current amount, or the amount of plating measured when the rotating electrode is set to low rotation are diffused as in the inside of the via hole. Since it can be obtained as a value corresponding to the thick state of the layer, it is possible to manage the plating by creating an actual plating progress state in a pseudo manner, and to realize a stable filling property.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to the following Example.

[Example 1]
Additive-free plating solution (hereinafter referred to as plating solution), Brightner solution A (compound represented by the following formula (10)), suppressor solution A (PEG), and leveler A (polyalkylpolyamine derivative) in the plating solution Standard solutions 1-1 to 1-3 shown in Table 1 were prepared by mixing a plating solution with a predetermined concentration added or a plating solution not added with a leveler.

Next, the Ar value [mC] of each standard solution at the rotational speeds of 2500 rpm and 1500 rpm of the rotating electrode was obtained by a CVS measuring device manufactured by ECI Technology, USA, and the obtained Ar values were used. The following formula (11)
_{(1-Ar 1500rpm / Ar 2500rpm} ) / (2500-1500) ... (11)
The k value is calculated by the following equation, and the relational equation between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a linear function by regression calculation, and the following calibration curve formula (12 )
y = (− 1.694 × 10 ⁵ ) x (12)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 998)),
Following formula (13)
Ar _2500rpm -Ar _1500rpm (13)
The k value is calculated by the following equation, and the relational expression between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a linear function by regression calculation, and the following calibration curve formula (14 )
y = −1166.941x (14)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 997.)
Was calculated respectively.

  Next, for plating solutions 1-4 and 1-5 with known leveler concentrations shown in Table 1, as in the case of the standard solution, the Ar value [mC of each plating solution at 2500 rpm and 1500 rpm of the rotating electrode. The k value was calculated by the above equation (11) using the obtained Ar value, and this was substituted into the calibration curve equation (12) to determine the leveler concentration. Further, the k value was calculated by the above equation (13), and this was substituted into the calibration curve equation (14) to obtain the leveler concentration.

  As a result, as shown in Table 1, the error is within ± 15% so that there is no risk of trouble in actual plating due to the influence of the measurement error, and the brightener and suppressor of the plating solution are not affected. Without saturation processing, the plating solution has a higher accuracy than the prior art, with an error range within ± 5% according to equations (11) and (12), and within an error range within ± 11% according to equations (13) and (14). The leveler concentration in the medium could be measured.

[Example 2]
The plating solution, the brightener solution B (compound represented by the following formula (15)), the suppressor solution A (PEG), and the plating solution or leveler in which the leveler B (polyamide derivative) is added to the plating solution at a predetermined concentration are added. Standard solutions for preparing a calibration curve 2-1 to 2-3 shown in Table 2 were prepared by mixing a non-plating solution.

Next, the Ar value [mC] (area of the peeled area, the same applies hereinafter) of each standard solution at the rotation speed of the rotating electrode of 2000 rpm and 500 rpm was determined by a CVS measuring apparatus manufactured by ECI Technology, USA, and the obtained each Using the Ar value at the rotational speed, the following formula (16)
(1-Ar _{500 rpm} / Ar _{2000 rpm} ) / (2000-500) (16)
The k value is calculated by the following equation, and the relational expression between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a linear function by regression calculation, and the following calibration curve formula (17 )
y = (− 4.803 × 10 ⁴ ) x (17)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 997.)
Was calculated.

  Next, for the plating solutions 2-4 to 2-10 with known leveler concentrations shown in Table 3, as in the case of the standard solution, the Ar value [mC of each plating solution at the rotational speed of the rotating electrode of 2000 rpm and 500 rpm] The k value was calculated by the above equation (16) using the obtained Ar value, and this was substituted into the calibration curve equation (17) to determine the leveler concentration.

  As a result, as shown in Table 3, the error is within ± 15%, which does not cause a problem in actual plating due to the influence of the measurement error, and the brightener and suppressor of the plating solution are not affected. It was possible to measure the leveler concentration in the plating solution with higher accuracy than the conventional case where the error range was within ± 8% without performing saturation treatment.

[Example 3]
Plating solution, Brightener solution C (compound represented by the following formula (18)), suppressor solution A, and plating solution in which leveler C (polyamine derivative) is added to the plating solution at a predetermined concentration, or a plating solution in which no leveler is added The standard solutions for preparing a calibration curve shown in Table 4 were prepared.

Next, after diluting the prepared standard solutions 3-1 to 3-5 with the plating stock solution to 1/2, each standard solution at the rotational speed of the rotating electrode of 2000 rpm and 500 rpm was measured with a CVS measuring device manufactured by ECI Technology, USA. The Ar value [mC] was determined, and using the obtained Ar value at each rotation number, the following formula (16)
(1-Ar _{500 rpm} / Ar _{2000 rpm} ) / (2000-500) (16)
The k value is calculated by the following equation, and the relational equation between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a quadratic function by regression calculation, and the following calibration curve formula (19 )
y = (6.215 × 10 ⁷ ) x ² − (3.640 × 10 ⁴ ) x (19)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 999),
Following formula (20)
1-Ar _500rpm / Ar _2000rpm (20)
The k value is calculated by the following equation, and the relational equation between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a quadratic function by regression calculation, and the following calibration curve formula (21 )
y = 27.624x ² −24.270x (21)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 999.)
Was calculated, and a calibration curve (FIG. 1) was prepared.

  Next, as for the plating solutions 3-6 to 3-12 with known leveler concentrations shown in Table 5, as in the case of the standard solution, the Ar value [mC of each plating solution at a rotational speed of the rotating electrode of 2000 rpm and 500 rpm] The k value was calculated by the above equation (16) using the obtained Ar value, and this was substituted into the calibration curve equation (19) to determine the leveler concentration. Further, the k value was calculated by the above equation (20), and this was substituted into the calibration curve equation (21) to obtain the leveler concentration.

  As a result, as shown in Table 5, the error is within ± 15%, which does not cause a problem in actual plating due to the influence of the measurement error, and the brightness of the brightener or suppressor with respect to the plating solution It was possible to measure the leveler concentration in the plating solution with higher accuracy than the conventional case where the error range was within ± 6% without performing saturation treatment.

[Example 4]
Table 6 shows a mixture of a plating solution, a brightener solution A, a suppressor solution A, and a plating solution in which leveler D (quaternary alkylamine) is added at a predetermined concentration to the plating solution or a plating solution in which no leveler is added. Standard solutions for preparing a calibration curve 4-1 to 4-3 were prepared.

Next, the Ar value [mC] of each standard solution at the rotation speeds of 2500 rpm and 1000 rpm of the rotating electrode was obtained by a CVS measuring device manufactured by ECI Technology, USA, and the obtained Ar values were used. The following formula (22)
(1-Ar _{1000 rpm} / Ar _{2500 rpm} ) / (2500-1000) (22)
The k value is calculated by the following equation, and the relational expression between the k value obtained with each standard solution and the leveler concentration giving the k value is approximated by a linear function by regression calculation, and the following calibration curve formula (23 )
y = (− 1.181 × 10 ⁵ ) x (23)
(Where x is the k value and y is the leveler concentration [mL / L]. The approximation is approximated as an expression passing through the origin (y intercept = 0). At this time, the correlation coefficient R ² is 0. 990.)
Was calculated.

  Next, for the plating solutions 4-4 and 4-5 with known leveler concentrations shown in Table 6, as in the case of the standard solution, the Ar value [mC of each plating solution at 2500 rpm and 1000 rpm of the rotating electrode is used. The k value was calculated by the above equation (22) using the obtained Ar value, and this was substituted into the calibration curve equation (23) to determine the leveler concentration.

  As a result, as shown in Table 6, the error is within ± 15%, which does not cause a problem in actual plating due to the influence of the measurement error, and the brightener and suppressor are not used for the plating solution. It was possible to measure the leveler concentration in the plating solution with a higher accuracy than the conventional case where the error range was within ± 3% without performing saturation treatment.

[Comparative Example 1]
Standard solution for preparing calibration curve shown in Table 7 by mixing plating solution, brightener solution A, suppressor solution A, plating solution with leveler A added to plating solution or plating solution without leveler added to plating solution R-1 to R-4 were prepared.

Next, the Ar value [mC] of each standard solution was obtained at a rotational electrode rotation speed of 2500 rpm using a CVS measuring device manufactured by ECI Technology, USA, and the relational expression with the leveler concentration giving the Ar value was calculated by regression calculation. The following calibration curve formula for leveler concentration by approximation of the next function (24)
y = −1.27z + 11.47 (24)
(In the formula, z is an Ar value, and y is a leveler concentration [mL / L]. The correlation coefficient R ^{2 at} this time was 0.993.)
Was calculated.

  Next, for the plating solutions R-5 to R-8 with known leveler concentrations shown in Table 8, the Ar value [mC] of each plating solution is obtained at a rotational speed of 2500 rpm of the rotating electrode, as in the case of the standard solution. The leveler concentration was determined by substituting the obtained Ar value into the calibration curve equation (24).

  As a result, as shown in Table 8, there are cases where the error exceeds ± 15% which does not cause a problem in actual plating due to the influence of the measurement error, and the results are more varied than the examples. became.

[Examples 5 and 6, Comparative Example 2]
Using the standard solution used in Example 1, in each Example and Comparative Example, as shown below, a calibration curve was obtained by regression calculation to create a calibration curve.
Example 5: A calibration curve is generated by approximation of a linear function using the k value calculated by the above equation (13). Example 6: A calibration curve is approximated by a quadratic function approximation by using the k value calculated by the above equation (20). Comparative Example 2: Create a calibration curve by linear function approximation using Ar value with the same method as Comparative Example 1

  Next, a plating solution containing unknown concentrations of Brightner A, Suppressor A, and Leveler A was prepared, and k values were obtained for this plating solution in the same manner as the corresponding calibration curve was prepared (Examples 5 and 6). ) Or the Ar value itself (Comparative Example 2), substituting these into the respective calibration curve formulas to measure the leveler concentration, and based on this measured value, the prescribed leveler concentration for performing actual plating The deficiency was added to the plating solution so that the plating solution used in each Example or Comparative Example was prepared.

  Next, a base material having a via hole with a hole diameter of 120 μm and a depth of 55 μm is immersed in the plating solution with the adjusted leveler concentration, and via filling is performed under each condition so that the film thickness of the base material surface becomes 15 μm. Copper plating was applied. The state of the via hole after plating is the difference in film height between the surface of the base material and the via opening by a laser microscope from the surface (value of h shown in FIG. 2. In FIG. 2, 1 is the base material, 2 Shows the copper plating film.) Table 9 shows the results of the evaluation and the presence or absence of voids by cross-sectional observation.

  From the results of Table 9, if the leveler concentration of the plating solution is adjusted by measuring the leveler concentration using the k value, the leveler action of the plating solution can be brought into an ideal state by a simple method. Further, the difference in film height is equal to or less than the plating film thickness on the surface of the base material, and the fillability of the plating solution can be easily ensured. In particular, the difference in the ratio of Ar to a predetermined value, that is, plating on the rotating electrode, each measured when the voltage is swept between the rotating electrode and the counter electrode while rotating the rotating electrode at two different rotation speeds. Of the two kinds of rotation speeds of the peak value of the amount of electricity or current required for dissolving or peeling the plating deposited on the rotating electrode or the amount of plating deposited on the rotating electrode. The ratio to the measured value at the time of several times or low speed, or the ratio to the product of the measured value at the time of high speed or low speed of the two kinds of speeds and the difference between the two kinds of speeds. By making the difference between the ratios of the above two rotation speeds k value, it is possible to obtain more excellent hole filling performance in actual plating without measuring the concentration of brightener or suppressor in advance. I understand that I can do it. This is because the difference in the action of the leveler in the diffusion layer represented by the difference in the ratio of Ar to the predetermined value described above is noted, and a result reflecting the state of the action is obtained. It is possible to prepare a plating solution in which the balance of plating growth between the outside and the inside is adjusted with high accuracy.

4 is a calibration curve in Example 3. It is a figure explaining the difference in the film | membrane height in a base-material surface part and a via opening part.

Explanation of symbols

1 Base material 2 Copper plating film

Claims (4)

The concentration of the nitrogen-containing additive in the plating solution containing the sulfur-based additive and / or the polymer-based additive and the nitrogen-containing additive without measuring the concentration of the sulfur-based additive and the polymer additive. Is measured by cyclic voltammetry,
For each of one or more plating standard solutions containing the additive at a known concentration, the measured values a and b are determined by rotating the rotating electrode at two different rotational speeds α and β,
Create a calibration curve by the characteristic value using the difference and / or ratio of the measured values a and b and the additive concentration of the plating standard solution,
Determination of the additive concentration of the plating solution, wherein the characteristic value is determined for the plating solution having an unknown additive concentration, and the additive concentration of the plating solution is determined based on the calibration curve from the characteristic value of the plating solution. Method. The characteristic values are the following (I) to (VI)
(I) Measured value a (Measured value A) −Measured value b (Measured value B)
(II) Measured value b (Measured value B) −Measured value a (Measured value A)
(III) 1-Measured value a (Measured value A) / Measured value b (Measured value B)
(IV) 1-Measured value b (Measured value B) / Measured value a (Measured value A)
(V) Measured value a (Measured value A) / Measured value b (Measured value B) -1
(VI) Measured value b (Measured value B) / Measured value a (Measured value A) -1
The additive concentration measuring method according to claim 1, wherein the value is obtained using any one of the following.   The method for measuring an additive concentration according to claim 1 or 2, wherein the plating solution is a copper plating solution containing a leveler as the nitrogen-containing additive.   A plating solution in which the concentration is determined by measuring the additive concentration by the method for measuring an additive concentration according to any one of claims 1 to 3 is used to fill holes or grooves in the substrate with plating. Plating method.

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