JP2003277998A - Plating apparatus, and method for controlling plating solution using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating apparatus capable of keeping the constant concentration of the additive to the plating solution through the plating work time, and a plating solution controlling method using the plating apparatus. <P>SOLUTION: The plating apparatus 100 calibrates the plating consumption coefficient per unit treatment number for each predetermined time, and calculates the replenishment amount to the consumption of the additive associated with the plating treatment by the 'periodically calibrated plating consumption coefficient × plating treatment number'. Therefore, the consumption of the additive agrees with the replenishment of the additive. As a result, the concentration of the additive contained in the plating solution 3 is maintained at a constant value. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus for plating a substrate to be plated, and more particularly to a plating apparatus capable of keeping the additive concentration of Cu plating solution constant throughout the plating operation time.

[0002]

2. Description of the Related Art A plating apparatus is required to keep a plating solution component (additive such as an accelerator) contained in a plating solution constant over a long period of time including a plating operation.

Specifically, as an example, the plating apparatus 10
0 is the plating cell 10 and the plating liquid tank 2 as shown in FIG.
0, the plating liquid analyzer 30 and the additive replenishing device 40 are included, and the additive replenishment is performed by the plating liquid analyzer 30 as follows.

First, the additive replenishing device 40 displays the additive concentration measurement results from the plating solution analyzer 30 at predetermined time intervals (3
The time, 6 hours, 12 hours, etc. can be set as appropriate, but as an example, it is set to 3 hours), the deviation from the target concentration of the additive is calculated, and the additive is replenished in the plating solution tank 20. Of course, when the additive concentration measurement result exceeds the target concentration of the additive, the additive is not replenished.

If such periodic centering of the additive concentration in the plating liquid tank 20 is performed on the basis of the actual measurement result, for example, every one minute, the problem of the additive concentration deviation occurs. However, in reality, the actual measurement of the additive concentration requires about 2.5 hours at the shortest, so that the actual measurement is performed at intervals of, for example, 3 hours. Therefore, the calculation of additive concentration for this 3 hours for example, by performing every 5 minutes, were trying to suppress the fluctuation of the additive concentration within between 3:00. For example, the following replenishment of additives was performed within a predetermined time interval calculated by, for example, every 5 minutes.

In the plating liquid analyzer 30, the additive concentration change coefficient Kt (ml / h) per unit time multiplied by the elapsed time irrespective of the plating process, and the unit of the amount of electric charge for plating (proportional to the plating film thickness) Additive concentration change coefficient Kq
(Ml / amp · h), additive target concentration Ct (m
1 / l) is input in advance. Here, as the additive concentration change coefficient Kq per unit plating charge amount, a constant value based on empirical estimation has been used.

The plating solution analyzer performs the calculation shown in the equation (1) every 5 minutes. _{C k = C (k-1} ) - at (Kt × T + Kq × Q ) ··· (1) where, _C k · · · This additive concentration calculation result _{C (k-1)} ··· last addition Agent concentration calculation result (however, additive target concentration when additive is replenished between the previous and present calculations) T ... C _(k-1) C _k Elapsed time from calculation · _{C (k-1)} cumulative plating charge amount _{S k = (Ct-C k} ) × V ··· (2) where, _S k · · · additives target concentration target concentration of the additive concentration from the calculation Amount of additive replenishment necessary for (calculation result) V ... total amount of plating solution in the plating apparatus Additive required to make the additive concentration calculated as described above the additive target concentration replenishing amount _{S k} is, for example, immediately replenishment of carrier is performed if equal to or more than 10 ml, 10 ml In the case of full, next time (after about 5 minutes)
It will wait for the calculation result of.

[0008]

However, as shown in FIG.
As shown in (a) and (b), the amount of carrier consumed by the plating process is proportional to the number of plated plates, not the integrated plating film thickness (∝ integrated plating charge amount). There is also a loose correlation between the integrated plating film thickness in FIG. 3A and the carrier consumption amount. This is because there is a loose correlation between the number of plated plates and the integrated plating film thickness as shown in FIG.

FIG. 6A is a diagram showing the number of plated plates and the carrier replenishment amount in the conventional plating apparatus. In the conventional method, the replenishment amount of the carrier with respect to the consumption by the plating process is calculated by Kq × integrated plating charge amount. 5
When only plating with a constant film thickness such as 50 nm or 3000 nm is performed, accumulated plating charge amount = charge amount per plate ×
Since the relationship of the number of processed sheets is established, the replenishment amount is proportional to the number of processed sheets as shown in the figure. As is clear from FIG. 6 (a),
In the conventional replenishment amount calculation, the replenishment amount greatly differs when the plating film thickness is different even if the number of processed sheets is the same.

On the other hand, as described above, the carrier consumption due to the plating process is proportional to the number of plated plates. If the number of plated plates is the same, the actual consumption will be the same, but in the conventional replenishment amount calculation, if the plating film thickness is different, the amount of replenishment will be different when thin-film plating and larger when thick-film plating. Guide the amount. As a result, naturally, the consumption amount and the replenishment amount do not match and the additive concentration changes.

FIG. 6B shows changes in the number of plated plates and the additive concentration from the target concentration when the conventional replenishment method is used. Conventionally, a certain constant value has been used for Kq based on empirical estimation, but even if this constant value is changed, if the plating of a plurality of plating film thicknesses is performed on the substrate, this concentration change is compensated for. You cannot do it.

In the actual plating lot processing, either one of the thick film plating and the thin film plating is rarely continued, and the thick film plating and the thin film plating are performed with a certain balance. As a result, the effect of increasing the concentration of the thick film plating and the effect of decreasing the concentration of the thin film plating shown in FIG. 6 (b) cancel each other out, so that as shown in FIG. Do not mean. However, biasing to either thick film plating or thin film plating at a certain frequency inevitably occurs in the actual plating phase (on product shipment). In this case, the additive concentration changes as shown in FIG. 6B, and the product is discarded due to deviation of the additive concentration, or shipment is stopped due to inability to perform the plating process.

FIG. 5 shows that the consumption amount of the carrier by the plating process depends on the number of processed plates, not on the integrated plating film thickness, and based on the knowledge that the carrier consumption amount per wafer and the elapsed time from the total amount of plating are exchanged. Is the result of examining. Conventionally, it was thought that the same amount of carriers would be consumed if the same plating treatment was performed. Therefore, a constant value based on empirical estimation has been used for Kq. However, as shown in FIG. 5, the consumption rate of the additive due to the plating process is not constant. The fact that the proportional coefficient corresponding to this consumption rate is constant is also the reason why the consumption amount by plating and the replenishment amount by the conventional method do not match.

As described above, FIG. 5 shows that the carrier consumption amount per unit number of processed sheets changes depending on the time from the total liquid exchange of the plating liquid and the like. In FIG. 3B, the proportional relationship between the carrier consumption amount and the number of sheets (= constant carrier consumption amount per unit number of processed sheets) is shown after a certain period of time has elapsed since the replacement of all plating liquids and a certain period of time. This is because it is internal data. Actually about 110 hours for liquid exchange
This is data for 130 hours. Since the change in the carrier consumption amount per unit number of processed sheets during this time is small, FIG.
The proportional relationship of (b) is obtained.

As described above, in the conventional plating apparatus, it is carried out to complement the centering of the additive concentration by the concentration measurement which can be carried out only about every 3 hours. For example, in the replenishment amount calculation every 5 minutes, the addition by the plating treatment is performed. The calculation of the replenishment amount with respect to the agent consumption has been performed with a constant proportional coefficient x integrated plating film thickness. However, the actual amount consumed by plating was the amount expressed by the coefficient that changes x the number of plated plates. Therefore, within the concentration measurement interval, the additive concentration deviates from the standard, the plating characteristics change, and as a result, a large amount of substrates are discarded and the yield of the substrates is significantly reduced in the plating process. .

An object of the present invention is to provide a plating apparatus capable of keeping the additive concentration of the plating solution constant throughout the plating operation time, and a plating solution management method using the same.

[0017]

The plating apparatus of the present invention comprises:
A plating cell for performing a plating process on a substrate, a plating solution tank having a function of constantly circulating and supplying and collecting a plating solution in the plating cell, and a concentration of an additive contained in the plating solution in the plating solution tank are measured. A plating solution analyzer and, based on the analysis results of the additive concentration of the plating solution analyzer, determine whether or not to replenish the plating solution tank with the additive, and add when it is determined to replenish. A plating apparatus having an additive replenishing device for replenishing a plating solution to the plating solution tank, wherein the plating solution analyzer measures the concentration of the additive contained in the plating solution in the plating solution tank every predetermined time. A value obtained by dividing the consumption amount of the additive by the plating treatment performed within the predetermined time by the number of substrates subjected to the plating treatment is calculated as a plating treatment additive consumption coefficient, and is calculated every monitoring time shorter than the predetermined time. Using the plating additive consumption coefficient, multiply the number of substrates plated in the monitoring time to calculate the plating dependent consumption predicted value of the additive, and add it together with the elapsed time dependent consumption of the additive. Based on the additive concentration at the previous monitoring one time before and the predicted value of the additive consumption, the additive concentration at the current monitoring was calculated, and the value was subtracted from the additive concentration. The additive replenishing device replenishes the plating solution tank with the replenishing amount of the additive when the replenishing amount multiplied by the liquid amount becomes equal to or more than a predetermined critical value.

In the above plating apparatus of the present invention, the elapsed time dependent consumption of the additive is calculated by multiplying the additive concentration change coefficient per unit time having a constant value by the monitoring time.

Further, in the above plating apparatus of the present invention,
The plating solution is a copper plating solution, and the additive is a thiol-based organic additive (accelerator).

Next, the plating solution management method of the present invention is a plating apparatus having a plating cell, a plating solution tank, a plating solution analyzer and an additive replenishing device, in which the substrate is immersed in the plating cell to carry out the plating treatment. The plating solution is constantly circulated in the plating cell to be supplied and collected, the concentration of the additive contained in the plating solution in the plating solution tank is measured by the plating solution analyzer, and the plating solution analyzer is measured by the additive replenishing device. Based on the analysis result of the concentration of the additive, it is determined whether or not the additive is replenished to the plating solution tank, and when it is determined that the additive is replenished, a predetermined amount of the additive is replenished to the plating solution tank. A method of controlling a plating solution, wherein the plating solution analyzer measures the concentration of an additive contained in the plating solution in the plating solution tank at predetermined intervals and is performed within the predetermined time. A value obtained by dividing the consumption amount of the additive by the plating process by the number of plated substrates is calculated as a plating treatment additive consumption coefficient, and the plating treatment additive consumption coefficient is calculated for each monitoring time shorter than the predetermined time. Using the number of substrates plated in the above-mentioned monitoring time, the plating-dependent consumption estimation value of the additive is calculated, and the addition-time estimation consumption value of the additive is calculated to be the additive consumption estimation value. The value obtained by subtracting the additive concentration at the current monitoring from the target concentration of the additive by calculating the additive concentration at the current monitoring based on the additive concentration at the previous monitoring before the previous time and the predicted value of the additive consumption amount. When the replenishment amount multiplied by the plating liquid amount becomes a predetermined critical value or more, the additive replenishing device replenishes the plating liquid tank with the replenishing amount of the additive agent for a monitoring time shorter than the predetermined time. To calculate the plating-dependent consumption estimation value of the additive by multiplying the number of substrates plated in the monitoring time by using the plating-treatment additive consumption coefficient, and combine it with the elapsed-time consumption consumption of the additive. As the additive consumption predicted value, the additive concentration obtained by subtracting the additive consumption predicted value from the additive concentration at the monitor start time is defined as the additive concentration at the monitor end time,
When the replenishment amount obtained by subtracting the additive concentration at the end of the monitor from the target concentration of the additive by the plating solution amount is equal to or higher than a predetermined critical value, the additive replenishing device is added to the plating solution tank. It is characterized in that the additive is replenished in the replenishing amount.

In the method for controlling a plating solution of the present invention, the concentration of the additive contained in the plating solution in the plating solution tank is measured every predetermined time, and the additive by the plating treatment performed within the predetermined time is measured. In the operation of calculating a value obtained by dividing the consumption amount by the number of plated substrates as a plating treatment additive consumption coefficient, the plating treatment additive consumption coefficient is an additive consumption amount per substrate to be plated. ,
One substrate is converted into the number of substrates standardized as one substrate having an area of a certain size.

In the plating solution management method of the present invention, the plating treatment performed by immersing the substrate in the plating apparatus in a plating cell is a plating treatment for plating the substrate with a plating film having a plurality of film thicknesses. Is.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view of a plating apparatus. The plating apparatus 100 mainly includes a plating cell 10, a plating solution tank 20, a plating solution analyzer 30, and an additive replenishing device 40. In the plating cell 10, the substrate 1 is opposed to the anode 2 and immersed in the plating solution 3, and a voltage E is applied between the substrate 1 and the anode 2 to plate Cu ²⁺ in the plating solution 3 on the surface of the substrate 1. At this time, the plating solution contains Cu ²⁺ , SO ^{4 −} , H ⁺ ,
In addition to Cl ⁻ , a thiol-based organic additive is contained at a certain concentration as a plating accelerator. In addition to these, organic polymer additives (inhibitors, polymers), etc. are included, but since the concentration of these additives changes substantially in proportion to time and does not depend on the plating treatment, The problem of the concentration of various additives does not occur.

Next, the plating solution tank 20 circulates the plating solution through the plating solution circulation tube 50 to constantly supply the plating solution to the plating cell 10, and the plating cell 10
Collect the plating solution from. Therefore, the additive concentrations of the plating solution 3 in the plating solution tank 20 and the plating cell are the same.

Next, the plating liquid analyzer 30 is a device for measuring the additive concentration of the plating liquid 3 in the plating liquid tank 20, and the additive replenishing device is based on the data of the additive concentration measured here. 40 is given an instruction as to whether or not the plating solution tank is replenished with the additive, and in the case of replenishment, the replenishment amount is also instructed.

Next, the additive replenishing device 40 follows the instruction from the plating solution analyzer 30 to add the additive to the plating solution tank 20.
When replenishing the plating solution, the plating solution tank 20 is replenished with the replenishment amount of the additive instructed by the plating solution analyzer 30.

The additive replenishing device 40 is a plating liquid analyzer 3
Additive concentration measurement results from 0 to a predetermined time interval (3 hours,
6 hours, 12 hours, etc. can be set appropriately, but as an example, 3 hours is received), the deviation from the target concentration of the additive is calculated, and the additive is replenished to the plating solution tank 20. Of course, if the additive concentration measurement result exceeds the target concentration of the additive, the additive is not replenished. This point is the same as the conventional method.

Now, a method of replenishing the additive, which is a feature of this embodiment, will be described. In the present invention, the calculation formula used for the concentration management by the calculation every 5 minutes, which is complementary to the management by the additive concentration centering by the actual measurement every predetermined time (for example, 3 h), is different. First, the additive replenishing device 40
Receives the additive concentration measurement result from the plating solution analyzer 30 at a predetermined proportional coefficient calibration time interval (3 hours, 6 hours, 12 hours, etc. can be set as appropriate, but is 6 hours as an example). The value obtained by subtracting the amount of additive consumption that is irrelevant to the plating process and that depends on the elapsed time from the decrease of
w (= carrier consumption per plating of one substrate at the time of calibration of the proportional coefficient).

That is, Kw is calculated by the following equation. ΔCLT is the concentration change during the proportional coefficient calibration time (for example, 6 hours), V is the total plating solution amount, SLT is the total additive replenishment amount within the proportional coefficient calibration time, and Kt is the natural additive consumption rate per unit time.
Assuming that the proportional coefficient calibration time is TLT and the number of plating treatments in the proportional coefficient calibration time is WLT, concentration change = (total additive replenishment amount−total additive consumption amount) / plating solution amount, ΔCLT = (SLT− ( Kt x TLT + Kw x WL
T)) / V holds. Therefore, Kw is calculated by the following equation. Kw = (SLT− (ΔCLT × V + Kt × TLT)) /
WLT In this way, unlike the prior art, the proportional coefficient Kw which is calibrated at every predetermined time is obtained.

Using this Kw, the plating solution analyzer 30 calculates the present additive concentration by calculation every 5 minutes in order to complement the control by the additive concentration centering by actual measurement every 3 hours, for example. The formula used to calculate the additive concentration every 5 minutes is the following formula (3) in which Kq × Q in the conventional formula (1) is replaced with Kw × W. C _k = C _(k−1) − (Kt × T + Kw × W) (3) Here, W is the number of substrates plated between the previous calculation and the present calculation, and the number of substrates is The number of substrates having an area of a certain size is converted into a standardized number. For example, if one 6-inch wafer is used,
The number of 8-inch wafers is 1.778.

After obtaining C _k , S _k is calculated by the equation (2) shown in the conventional method. S _k = (Ct−C _k ) × V (2) As a result, for example, when S _{k of the} formula (2) becomes 10 ml or more, the additive replenishing device 40 immediately adds the plating solution to the plating solution tank 20. If the agent is replenished and less than 10 ml,
After about 5 minutes, the additive concentration measurement result C _k of this time is substituted into C _(k−1 ) of the equation (3), and the next calculation of C _k and S _k is performed. The procedure after obtaining C _k by the equation (3) is the same as the conventional method.

As described above, after calibrating at a predetermined proportional coefficient calibration time, Kw is multiplied by the number of plating treatments to obtain the consumption amount by the plating treatment, and if the additive is replenished, only the consumed amount is replenished. And the additive concentration stabilizes. For this reason, the centering interval can be lengthened, the regular maintenance interval of the analyzer and the device life can be extended, and the secondary effects of reducing the amount of analytical chemicals used can also be obtained.

Here, the phenomenon that supports the fact that the additive consumption amount is approximately proportional to the number of plated plates will be described.
As described above, FIG. 3B is a graph showing the dependence of the additive (carrier) consumption amount by the plating process on the number of plated plates (using a substrate of a fixed size).
As is clear from comparison between this graph and the graph of FIG. 3A, the consumption amount of the additive (carrier) is higher than the correlation with the integrated plating charge amount of FIG. It can be seen that the correlation with the number of processed sheets is stronger. Figure 3 (a)
The reason why has a loose correlation is as described above.

Here, this strong correlation is due to the following reason. That is, since the additive is adsorbed on the surface of the substrate at the moment when the substrate is immersed in the plating solution, the additive consumption amount due to the plating treatment of the substrate is mainly determined by the surface area of the substrate and further the number of the plated treatment of the substrate. It FIG. 2 is an enlarged schematic cross-sectional view of a part of the surface of the substrate for schematically explaining the phenomenon using Cu plating as an example.

First, as shown in FIG. 2A, a groove 51 is provided in the substrate 1, and a Cu seed layer 52 is formed in advance by sputtering on the entire surface of the substrate including the groove 51. When this substrate 1 is immersed in the plating solution, as shown in FIG.
The carrier (plating accelerator) 53 is evenly adsorbed on the surface of the Cu seed layer 52.

Next, when Cu plating is started, FIG.
As described above, the inside of the groove 51 is gradually filled with the Cu film 54, and the surface area of the Cu film 54 in the groove becomes small. At this time, the carrier 53 adsorbed on the surface of the Cu seed layer 52 exists on the substrate surface even if the Cu film 54 grows. As a result, the carrier density becomes relatively high inside the groove where the surface area of the Cu film 54 is small. Therefore, the plating in this portion is promoted.

Next, as shown in FIG.
As shown in (c), the carrier density inside the groove is further increased, and the groove is completely filled with the Cu film 54.

As described above, the consumption amount of the additive in the plating process is mainly determined by the surface area of the substrate and further the number of substrates subjected to the plating treatment, and the plating film thickness is the amount of the plating charge regardless of the consumption amount of the additive. It turns out that is decided by.

As described above, according to the plating apparatus of the present invention and the plating liquid management method using the plating apparatus, the carrier consumption amount by the plating treatment is calibrated periodically (for example, every 6 hours) by a coefficient (Kw). ) × the number of plating treatments was used to calculate the additive consumption amount for each monitoring time (for example, 5 minutes), and it was decided to replenish the additive together with the consumption over time. The control by concentration centering by measuring the additive concentration every 3 hours is completely complemented, and it becomes possible to maintain the concentration of the additive contained in the plating solution constant over the operating time, resulting in a large substrate yield. I was able to raise it.

[0040]

As described above, according to the present invention, the consumption of the additive by the plating process is proportional to the number of processed plates, not to the integrated plating film thickness, and the coefficient is not constant but changes. Based on the proportional coefficient (Kw) calibrated for each predetermined time × the number of plated plates, the additive consumption amount is calculated for each monitoring time (for example, 5 minutes), and the consumption is calculated as the time elapses. Since it was decided to replenish the additive, the control by concentration centering by measuring the additive concentration every predetermined time (for example, 3 hours) was completely complemented, and the concentration of the additive contained in the plating solution was kept constant over the operating time. It is possible to maintain. Therefore, by using the plating apparatus according to the present invention, it becomes possible to produce a substrate on which a plating film with a predetermined attachment (embedding property, etc.) is plated over the operating time of the plating apparatus, and the substrate is discarded. It is possible to obtain an effect that the yield of the substrate is not significantly reduced in the plating process.

Further, according to the present invention, since the consumption amount by the plating process and the replenishment amount are the same, the additive concentration is stable. Therefore, the frequency of additive concentration centering due to measurement can be reduced. As a result, the regular maintenance interval of the analyzer and the life of the analyzer are extended, and the secondary effect of reducing the amount of the analytical chemicals used is also obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a plating apparatus used in an embodiment of the present invention.

FIG. 2 is an enlarged schematic cross-sectional view of a part of the surface of the substrate for schematically explaining a phenomenon in which the additive consumption amount due to plating treatment strongly depends on the number of plating treatments.

FIG. 3 is a graph showing the dependence of the additive (carrier) consumption amount by the plating process on the integrated plating charge amount and the dependence on the number of plating processes (using a substrate of a fixed size).

FIG. 4 is a graph showing the relationship between the cumulative amount of plating charges and the number of plating treatments (using a substrate of a fixed size) in the data of FIG.

FIG. 5 is a graph showing the elapsed time dependency of the consumption amount of an additive (carrier) by a 200 nm substrate (one plate is plated.

FIG. 6A shows the relationship between the amount of replenished carrier and the number of plated substrates when the conventional method is used (the plating film thickness is 2
(B) is a graph showing the relationship between the carrier concentration change and the number of plated substrates (calculated value, only two types of plating film thickness) when the conventional method is used. is there.

FIG. 7 is a graph showing the relationship between the carrier concentration change and the number of plated substrates (actual data, plating film thickness is 3 or more) when the conventional method is used.

[Explanation of symbols] 1 substrate 2 anode 10 plating cell 20 plating bath 30 Plating liquid analyzer 40 Additive replenishing device 50 plating solution circulation tube 51 groove 52 Cu seed layer 53 Carrier (plating accelerator) 54 Cu film

Claims (8)

[Claims] 1. A plating cell for plating a substrate, a plating solution tank having a function of constantly circulating and supplying and collecting a plating solution to the plating cell, and an additive contained in the plating solution in the plating solution tank. And a plating solution analyzer for measuring the concentration of the plating solution analyzer, and determines whether or not to replenish the plating solution tank with the additive based on the analysis result for the concentration of the additive of the plating solution analyzer, and determines to replenish. A plating apparatus having an additive replenishing device that replenishes the additive to the plating solution tank when the plating solution analyzer is used, wherein the plating solution analyzer is configured to adjust the concentration of the additive contained in the plating solution in the plating solution tank for a predetermined time. Calculated as the plating treatment additive consumption coefficient, which is calculated by dividing the consumption amount of the additive by the plating treatment performed within the predetermined time by the number of the plated substrates, and is shorter than the predetermined time. Mo The plating-dependent additive consumption coefficient of each additive is multiplied by the number of substrates plated during the monitoring time to calculate the plating-dependent consumption predicted value of the additive, and the elapsed-time-dependent consumption of the additive is calculated. Based on the additive concentration at the previous monitoring one time before and the predicted value of the additive consumption at this time, the additive concentration at the current monitoring is calculated and calculated from the target concentration of the additive. When the replenishment amount obtained by multiplying the value obtained by subtracting the additive concentration at the time of monitoring at this time by the plating liquid amount is equal to or higher than a predetermined critical value, the additive replenishing device causes the plating liquid tank to have the replenishment amount of the additive A plating device characterized by replenishing. 2. The plating apparatus according to claim 1, wherein the elapsed time-dependent consumption amount of the additive is calculated by multiplying an additive concentration change coefficient per unit time having a constant value by the monitoring time. 3. The plating apparatus according to claim 1, wherein the plating solution is a copper plating solution, and the additive is a thiol-based organic additive (accelerator). 4. In a plating apparatus having a plating cell, a plating solution tank, a plating solution analyzer and an additive replenishing device, the substrate is immersed in the plating cell for plating, and the plating solution is constantly circulated in the plating cell by the plating solution tank. Supplied and collected, the concentration of the additive contained in the plating solution in the plating solution tank is measured by the plating solution analyzer, and the analysis result for the concentration of the additive in the plating solution analyzer is received by the additive replenishing device. A method of controlling a plating solution, in which a predetermined amount of additive is replenished in the plating solution tank when it is determined that the additive is replenished in the plating solution tank. In the liquid analyzer, the concentration of the additive contained in the plating solution in the plating solution tank is measured every predetermined time to measure the consumption amount of the additive due to the plating process performed within the predetermined time. A value divided by the number of processed substrates is calculated as the plating treatment additive consumption coefficient, and the plating treatment additive consumption coefficient is used at each monitoring time shorter than the predetermined time to perform plating treatment within the monitoring time. Multiply the number of substrates that have been used to calculate the plating-dependent consumption estimation value of the additive, and add it with the elapsed time-dependent consumption consumption of the additive to obtain the addition agent consumption prediction value And the additive concentration at this time monitoring is calculated based on the above and the additive consumption estimated value, and the replenishment amount is calculated by multiplying the value obtained by subtracting the additive concentration at this monitoring time from the target concentration of the additive by the plating solution amount. When the additive replenishing device replenishes the plating solution tank with the replenishing amount of the additive at a predetermined critical value or more, the additive consumption coefficient of the plating treatment is calculated for each monitoring time shorter than the predetermined time. Then, the estimated plating-dependent consumption amount of the additive is calculated by multiplying the number of substrates plated during the monitoring time, and the estimated consumption amount of the additive is calculated together with the elapsed time-dependent consumption amount of the additive, The additive concentration obtained by subtracting the additive consumption predicted value from the additive concentration at the start time was taken as the additive concentration at the end of the monitoring, and the target concentration of the additive was subtracted from the additive concentration at the end of the monitoring. A method of managing a plating solution, wherein the additive replenishing device replenishes the plating solution tank with the replenishment amount of the additive when the replenishment amount multiplied by the plating solution amount exceeds a predetermined critical value. . 5. The method for managing a plating solution according to claim 4, wherein the elapsed time-dependent consumption amount of the additive is calculated by multiplying an additive concentration change coefficient per unit time having a constant value by the monitoring time. . 6. The concentration of the additive contained in the plating solution in the plating solution tank is measured every predetermined time, and the consumption amount of the additive due to the plating process performed within the predetermined time is measured in the plated substrate. In the operation of calculating a value divided by the number of sheets as a plating treatment additive consumption coefficient, the plating treatment additive consumption coefficient is an additive consumption amount per substrate to be plated, and one substrate is The method for managing a plating solution according to claim 4, wherein the number of substrates having one size area is converted into a standard number. 7. The method for controlling a plating solution according to claim 4, 5 or 6, wherein the plating solution is a copper plating solution, and the additive is a thiol-based organic additive (accelerator). 8. The plating apparatus according to claim 4, wherein the plating process in which the substrate is immersed in a plating cell is a plating process for plating a plating film having a plurality of film thicknesses on the substrate. The method for managing a plating solution according to the item 1.