TW201425924A - Method for monitoring the filling properties of a copper electrolyte - Google Patents

Abstract

The present invention concerns a method for monitoring the via filling properties of copper electrolytes. The method comprises the steps of calculating a cathodic current density range and/or the corresponding potential range for a given via geometry, recording a current-voltage diagram in the cathodic current range of the current for at least two different rotation speeds of the rotating disc electrode within the potential range calculated for said given via geometry.

Description

Method for monitoring copper electrolyte filling properties

This invention relates to a method of monitoring the channel filling properties of a copper electrolyte during use.

Electroplating copper from an acid plating bath is a well-known method and is used, for example, in the manufacture of printed circuit boards, IC substrates, and germanium-based microelectronic devices.

Electroplated copper is used to form conductive circuits and contact areas for soldering and bonding operations. Such uses for copper electroplating are generally associated with channel fill, such as through-the-channel (TSV), through glass via (TGV), through ceramic via (TCV), blind microchannel (BMV), and via (TH). Both BMV and TSV are channels with one opening, and TH has openings on both sides of the substrate. The TGV and TCV can be channels with one opening or channels with openings on both sides of the substrate.

Different organic additives (such as brighteners, carriers, and leveling agents) must be added to the acidic copper electrolyte to meet the requirements for filling the channels. Therefore, it is desirable to monitor the concentration of such organic additives and their decomposition products in the copper electrolyte during use of the electroplating bath to ensure stable performance by, for example, supplementing the organic additive or pouring a portion or the entirety of the electroplating bath.

One standard method of monitoring such organic additives is cyclic voltammetry (CVS), which can be used as an in-line process, that is, to continuously provide information about organic additives during the use of a copper electrolyte. However, the accuracy of this method is limited. Especially in the case of the need to use copper to plate more challenging substrate features, such a method fails: according to CVS measurement, the concentration of organic additives The degree is still within the recommended range, but the channel filling properties studied by microscopically examining the cross-section of the recessed structure reveal incomplete filling of the copper or undesirable voids in the recessed structure that is not completely filled.

Other methods known in the prior art are electrochemical measurement techniques that use information obtained by convective-dependent adsorption of such additives on the surface of the electrode: an electrochemical method for monitoring the filling properties of the channel has been developed by T.-H .Tsai and J.-H. Huang describe ("Copper electrodeposition in a through-silicon via evaluated by rotating disc electrode techniques", J. Micromech. Microeng. 20 (2010), pages 1 to 5). The electrochemical measurements shown in Figure 1 were used to simulate the mass transfer environment on the surface of the wafer substrate, at the bottom of the shallow and deep channels, respectively. The geometry of a given channel is not considered and the different current densities present on, for example, the top of the substrate surface and the bottom of the channel. The methods disclosed herein are shown only for copper electrolytes comprising PEG (typical carrier-inhibitor additive) and SPS (typical brightener-accelerator additive) as additives. The electrolytes studied did not contain any leveling agent additives.

A method of analyzing a copper plating solution is disclosed in US 7,820,535 B2. The time-dependent potential change at a cathode current of -0.1 to -20 A/dm ^{2 was} measured, and the obtained data was roughly estimated from the Boltzmann's function. In this method, only one cathode current value is applied. Therefore, the cathode current distribution existing in the case where the substrate has a channel cannot be observed by this method.

Method for evaluating filling performance of copper plating formula by using a constant current method It has been disclosed by W.-P. Dow and Chen-Wei Liu ("Evaluating the filling performance of a copper plating formula using a simple gavanostat method", Journal of the Electrochemical Society 153 (2) C190-C194 (2006). According to this method, only one current value is applied. Therefore, the current distribution existing in the case where the substrate has a channel cannot be observed by this method.

The object of the invention

Accordingly, it is an object of the present invention to provide a method of monitoring the channel filling properties of a copper electrolyte during use of the copper electrolyte, the copper electrolyte being particularly sensitive to leveling agent additives and their respective decomposition products.

This invention relates to a method of monitoring the channel filling properties of a copper electrolyte. The method can be used to monitor channel fill properties during the use of copper electrolytes in the fabrication of, for example, printed circuit boards, IC substrates, and semiconductor-based microelectronic devices. The method can also be used to screen for novel leveling agent additives for copper electrolytes and to control the quality of the leveling agent additives.

The method of monitoring the filling properties of a copper electrolyte comprises the steps of: a) providing a substrate having at least one channel, b) calculating at least one of the openings at the applied cathode current density at the top (3) of the substrate surface. The cathode current density value required to completely fill the channel with the metal in the bottom region (2) of the channel, wherein the required cathode current density value at the bottom of the channel having an opening (2) is calculated by: [in the channel Required cathode current density in the bottom region (2)]= [Predetermined cathode current density applied to the top (3) of the substrate surface] or calculated at the top (3) of the substrate surface at the predetermined cathode current density at the center (5) of the channel having openings on both sides of the substrate The cathode current density required to conformally fill the channel with metal, wherein the required cathode current density at the center (5) of the channel having openings on both sides of the substrate is calculated by: [with openings on both sides of the substrate Cathodic current density at the center of the channel (5)]= [Predetermined cathode current density applied to the top (3) of the substrate surface]

And thereby deriving a range of cathode current densities, wherein the effect of the leveling agent additive of the predetermined copper electrolyte and the corresponding decomposition product on the channel filling property can be obtained, wherein the cathode current density range is selected when the channel is selected from the channel having one opening The cathode current density applied to the surface of the substrate is within a range of cathode current densities calculated on the bottom (2) of the channel, and wherein the cathode current density range is between the substrate and the channel having an opening on both sides of the substrate The cathode current density applied to the top is within the range of cathode current density calculated at the center of the channel (5), c) recorded by linear sweep voltammetry at at least two different rotational speeds of the turntable electrode in a three-electrode configuration Current-voltage curve over the range of cathode currents of the current, And d) by comparing the current-voltage curve recorded in step c) within the range of cathode current densities obtained in step b), recorded in step c) from the range of cathode current densities calculated in step b) Data to obtain the channel filling properties of a given copper electrolyte under a given channel geometry.

The method of the present invention may further comprise the step of: e)1 in the case where the channel is selected from the channel having an opening, the cathode current density determined in step b) is higher at the predetermined potential obtained in step c) The cathode current at the rotational speed is higher than or equal to the cathode current at the lower rotational speed at this potential, supplementing the leveling agent additive, or e) 2 in the case where the channel has an opening on both sides of the substrate, in the step Supplementary leveling agent in the case where the cathode current at a higher potential and the cathode current at a lower speed at a given potential in the range of the cathode current density determined in step c) are different from each other additive.

The method of the present invention utilizes different rotational speeds of the turntable electrodes in a three electrode configuration, as well as cathode current densities applied to the top of the substrate surface and current densities calculated on the bottom of the channel having a particular geometry. Therefore, in the case where the channel has an opening, both the cathode current density on the top surface of the substrate and the calculated cathode current density on the bottom of the channel are used to determine the effect of the leveling agent additive and the respective decomposition products in step b). The areas of the measured data.

For a channel with two openings, such as a through channel, use a substrate table The cathode current on the top of the surface and the calculated cathode current density at the center of the channel with two openings to determine the data in step b) with the effect of the leveling agent additive and the respective decomposition products And other areas.

The method of the present invention utilizes two general principles: the cathode current density during electroplating of copper into a channel (1) having an opening (such as TSV or BMV) is at the bottom of the channel (2) than at the top of the substrate surface (3) ) Be high. The definition of the term "bottom" (2) of the channel (1) and the "top" (3) of the substrate surface in the case of a channel having an opening is shown in Figure 1(a).

For example, a TSV having a depth of 25 μm and a diameter of 5 μm requires 25 minutes to fill at a cathode current density of -0.2 A/dm ² , which also corresponds to the cathode present on the top of the substrate surface (3). Current density (assumed: 100% current efficiency and ignoring potential effects). In the case where the copper deposited on top of the surface of the substrate should have a thickness of 1.2 μm, the required cathode current density at the bottom (2) of the TSV needs to be 20 times higher than at the top (3) of the substrate surface. This value is 20 by using the volume of the TSV completely filled with copper:

Divided by the volume of copper deposited on top of the surface of the substrate (in this example, the deposit has a height of 1.2 μm and a diameter of 5 μm):

Using Faraday's law (Farady's law) and is applied to the top surface of the substrate _surface is _a cathodic current density I -0.2 A / dm ^2:

In the exemplary TSV geometry, the required cathode current density I _TSV at the bottom (2) of the channel is calculated as follows: I _TSV = -0.2 A/dm ² . 20=-4 A/dm ² .

The same method of obtaining the relevant cathode current density or individual cathode current or potential range in the current-voltage curve over the range of cathode currents of the current to evaluate the channel filling properties of the copper electrolyte is applicable to the BMV type channel.

The cathode current density at a BMV (1) with a depth of 80 μm and a diameter of 100 μm and a desired copper layer thickness of 20 μm on the top of the substrate must be at the bottom (2) of the BMV than at the top of the substrate surface (3) The upper average is four times higher to get the full fill of the BMV.

Mass transfer within a channel having an opening, such as BMV or TSV, is only caused by diffusion of additives such as leveling agent additives, while mass transfer on the top of the substrate is primarily caused by convection. Therefore, the absolute cathode current density must be higher at a given potential without convection than in the case of electrolyte convection. Only in this case can the desired channel fill be achieved. Therefore, when the absolute cathode current density without convection at a given potential is lower than or equal to the cathode current density in the case of electrolyte convection at the same potential, it is necessary to add (supplement) a leveling agent to the copper plating bath. Additives to achieve or maintain the desired channel filling properties.

The method of the present invention uses the characteristics described above to simulate different electrolyte convection conditions using different rotational speeds of the turntable electrodes (RDE) in a three electrode configuration. For example, a rotational speed of 0 rpm is similar to no electrolyte convection and a rotational speed of >0 rpm is similar to electrolyte convection. It is worth noting that different electrolyte convection conditions can be simulated with a first rotational speed of, for example, 100 rpm and a second rotational speed of, for example, 1000 rpm, or vice versa.

In order to eliminate the contribution of other bath components (such as copper ions) to the resulting spin-dependent current-potential curve over the range of cathodic currents of the current, only mass transfer of other bath components (such as copper ions) is not observed using these curves. These parts of the relevant contributions are used to evaluate channel fill properties. Calculate the relevant current-potential curve as described above for an exemplary TSV geometry of 25 μm depth, 5 μm diameter and a 1.2 μm thick copper layer on top of the TSV and the applied cathode current density of −0.2 A/dm ² range.

If the channel has openings (such as TH) on both sides of the substrate, there are different conditions because the electrolyte flows through the channel from the front and back sides of the substrate. Thus, when applying the method of the present invention to monitor the filling properties of a copper electrolyte in a channel having openings on both sides of the substrate, the cathode current density measured at at least two different rotational speeds of the turntable electrode in a three-electrode configuration And the cathode current should be matched to a narrow range within a predetermined measurement range to obtain the desired fill. The ratio of the cathode current density at the center of the channel having openings on both sides of the substrate and the top of the corresponding substrate surface was calculated by the same method as in the case of the channel having one opening. The definition of the term "center" (5) is shown in Figure 1(b) for a channel having an opening on both sides of the substrate. Conformal metal filling means electroplating TH with copper, in which the electroplated copper layer is in TH There is a uniform layer thickness.

For example, in the case where the turntable electrode has an effective surface of 7.1 mm ² , the cathode current density of -0.2 A/dm ² (= -0.2.10 ^-2 A/cm ² ) corresponds to a cathode current of about -0.14 mA. And the cathode current density of -4 A/dm ² (= -4.10 ^-2 A/cm ² ) corresponds to a cathode current of about -2.84 mA.

The cathode current range is determined by the method described above with respect to the cathode current values of -0.14 mA and -2.84 mA obtained with RDE having an effective surface of 7.1 mm ² , wherein the current-voltage curve in the range of the cathode current of the current is TSV with a depth of 25 μm and a diameter of 5 μm, a 1.2 μm thick copper layer on top of the TSV, an applied cathode current density of -0.2 A/dm ² and a fill time of 25 minutes to obtain channel filling for a given copper electrolyte Information about the nature.

Deriving a potential value at the bottom of the TSV (1) by a current-voltage curve in a range of cathode currents at -4.10 ^-2 A/cm ² at, for example, 0 rpm; and 2. at, for example, 1000 rpm The potential value at the top of the substrate surface is derived from the current-voltage curve in the range of the cathode current from -0.2.10 ^-2 A/cm ² to obtain the relevant potential range. Therefore, the relevant potential range for this particular channel geometry is in the range of about -0.3 V (compared to Ag/AgCl) to about -0.2 V (compared to Ag/AgCl). This is shown in Figure 2.

The same method of obtaining the relevant cathode current density and corresponding potential range in the current-voltage curve over the range of cathode currents of the current as described above can be applied to any other channel geometry.

Subsequently, a current-voltage curve in the cathode range of the current was recorded by means of linear sweep voltammetry (LSV).

A three-electrode comprising a turntable electrode (RDE) having a copper surface, a reference electrode (e.g., an Ag/AgCl reference electrode), and preferably a counter electrode of a platinum electrode is used in the method of the present invention.

The turntable electrode can be, for example, a copper electrode or a platinum electrode having a copper surface. The platinum electrode can be used after the copper layer is deposited by depositing, for example, a copper electrolyte containing no organic additive onto the entire surface of the electrode.

Subsequently, the three electrode configuration is brought into contact with a copper electrolyte containing a leveling agent additive.

In a preferred embodiment of the invention, the RDE having a copper surface is adjusted in a copper electrolyte comprising a leveling agent additive prior to LSV measurement. The adjustment can be achieved, for example, by applying a current of, for example, -0.4 A/dm ² for 300 seconds at a rotational speed of 0 rpm. Such conditioning steps are optionally selected and depend on the kinetics of the interacting organic additives in the respective copper electrolytes.

The current-voltage curve over the range of cathodic currents of the current in the absence of non-natural electrolyte convection (0 rpm) was measured, followed by a current-voltage curve over the range of cathodic currents controlling the current at convection (>0 rpm). Control convection is regulated by a calibrated turntable electrode (RDE). A copper-electrolyte that affects the filling characteristics of the leveling agent additive and its decomposition products by comparing the current-voltage curves in the current range determined by the process in the process of filling a channel having a certain size by electroplating. An indication of the fill performance.

Therefore, the LSV measurement is performed for at least two different rotational speeds of the RDE. The speed to be applied depends on the equipment used for this purpose. Preferably, one of 0 to 100 rpm and another speed of more than 100 rpm are applied to each other. LSV scan (or vice versa). Preferably, a rotational speed of the turntable electrode in the range of 0 to 100 rpm and a second rotational speed of the turntable electrode of greater than 100 rpm are applied in step c).

The scanning speed is set to a value that produces the required accuracy of the method and the maximum time allowed due to the conditions of use of the copper electrolyte during manufacture. In addition, the scanning speed must allow the leveling agent additive and its decomposition products to be quasi-statically adsorbed on the surface of the RDE. Therefore, the scanning speed in the range of 0.1 to 50 mV/s is preferable for each LSV measurement cycle.

Different data analysis methods can be used in the method of the present invention: the cathode current value obtained by the higher rotation speed or the lower rotation speed is obtained by dividing the data obtained at the higher rotation speed of the RDE by the lower rotation speed of the RDE. The curve obtained by the data. The data obtained from these curves can be further processed to obtain information about the channel filling properties of the copper electrolyte. The value of the area below and above the zero line is numerically integrated over the range of cathode currents depending on the geometry of the channel filled with copper. Absolute and indicative of the channel filling properties of the copper electrolyte under consideration. In the case where the channel is TSV or BMV, the absolute sum is higher and the channel filling is better.

Another method of data analysis involves plotting the data obtained by the method of the present invention as a plot showing the ratio of potential to cathode current (i.e., resistivity) versus potential.

Another data analysis method comprises the steps of: a) selecting a potential value in the LSV map that is within a calculated potential range of a given channel geometry; and b) from the potential value at a second rotational speed rpm 2 The obtained cathode current or cathode current density value minus the value obtained at the first rotational speed rpm 1 Value, where rpm 2 < rpm 1. Such a procedure is suitable, for example, when monitoring copper electrolyte during use in the method of the invention. In the case where the channel to be filled with copper is TSV or BMV, the decreasing curve shows the deterioration of the channel filling property of the given electrolyte, that is, the concentration of the active leveling agent additive is lowered. The stable concentration of the active leveling agent additive is indicated by a curve without slope. The improvement of the data analysis method is applied in Example 5 and is shown in Figure 7, where the ratio of potential to cathode current at different rotational speeds of RDE at -210 mV is subtracted from each other and for processing time (ie, application) Draw at the plating time of the electrolyte. This data analysis method is particularly suitable for indirectly monitoring the level of leveling agent additive during the manufacture of printed circuit boards, metallized semiconductor wafers, and the like during the use of copper electrolytes.

The three-electrode configuration can be prepared for new measurements using the following procedure: rinsing the electrode with water, preferably deionized water, and removing the deposition during LSV scanning by, for example, immersing the RDE in dilute HNO ₃ followed by rinsing with water The copper layer.

The three-electrode configuration can now be used to measure the channel fill properties of another batch of copper electrolyte.

A test protocol in accordance with one embodiment of the present invention is summarized in Table 1, which allows measurement of channel fill properties of different batches of copper electrolyte.

After measuring the completion of one copper electrolyte batch (step 5), the preliminary three electrode configuration is used to measure another copper electrolyte batch (steps 6 through 9 and subsequent steps 1 through 4).

Instance

The invention is further illustrated by the following non-limiting examples.

Experimental configuration and general procedures

A three-electrode configuration consisting of a turntable electrode (RDE) with a copper surface, an Ag/AgCl reference electrode, and a platinum counter electrode was used throughout all experiments. All steps are separated from the counter electrode by a salt bridge from start to finish.

Linear sweep voltammetry (LSV) with a scan speed of 10 mV/s and different rotational speeds of RDE was applied.

The LSV measurements were compared to micrographs of the cross section of the copper filled recessed structure to demonstrate the accuracy of the method of the present invention.

Use the following procedure to study the data derived from the LSV measurements at different RDE speeds: depending on the depth and diameter of the channel to be filled, on the top of the substrate surface The thickness of the desired copper layer and the cathode current density applied to the top of the substrate surface are calculated taking into account the range of cathode currents used to obtain the information required for the channel fill properties of the copper electrolyte under investigation.

Subsequently, LSV measurements were taken at 0 rpm and 1000 rpm of the RDE. The sweep potential range is +0.1 V to -0.6 V at all three speeds (compared to the Ag/AgCl reference electrode).

The overall test protocol used in all examples is summarized in Table 2.

Example 1

The channel filling properties of the acidic copper electrolyte containing the leveling agent additive suitable for channel filling were determined using the test protocol of Table 2.

The data obtained over the range of calculated potentials required for BMV with a given geometry at a first rotational speed of 0 rpm of RDE and a second rotational speed of 1000 rpm of RDE is shown in Figure 3(a).

Here, the absolute cathode current density is lower at 1000 rpm than the absolute cathode current density obtained at 0 rpm of the RDE (i.e., no rotation).

A good correlation between the copper electrolyte characterization obtained by means of LSV and the cross section of the sample studied by optical microscopy was observed (Fig. 3(b)). The photomicrograph shows the fully filled BMV.

Example 2

The channel filling properties of the acidic copper electrolyte containing the leveling agent additive not suitable for channel filling were determined using the test protocol of Table 2.

The data obtained over the range of calculated potentials required for a BMV having a given geometry at a first rotational speed of 0 rpm of RDE and a second rotational speed of 1000 rpm of RDE is shown in Figure 4(a).

Here, the cathode current density at 1000 rpm is higher than the former at or about -0.24 V at a potential of about -0.3 V to about -0.24 V compared to the curve obtained at 0 rpm. Equal to the potential range of -0.21 V.

A good correlation between the copper electrolyte characterization obtained by means of LSV and the cross section of the sample studied by optical microscopy was observed (Fig. 4(b)). Microscopic photo The film shows BMV that is not completely filled.

Example 3

The channel filling properties of the acidic copper electrolyte containing the leveling agent additive suitable for channel filling were determined using the test protocol of Table 2.

The data obtained over the range of calculated potentials required for TSVs of a given geometry at a first rotational speed of 0 rpm of RDE and a second rotational speed of 1000 rpm of RDE is shown in Figure 5(a).

Here, the absolute cathode current density is lower at 1000 rpm than the absolute cathode current density obtained at 0 rpm of the RDE.

A good correlation between the copper electrolyte characterization obtained by means of LSV and the cross section of the sample studied by optical microscopy was observed (Fig. 5(b)). The photomicrograph shows the fully filled TSV.

Example 4

The channel filling properties of the acidic copper electrolyte containing the leveling agent additive not suitable for channel filling were determined using the test protocol of Table 2.

The data obtained over the range of calculated potentials required for TSVs of a given geometry at a first rotational speed of 0 rpm of RDE and a second rotational speed of 1000 rpm of RDE is shown in Figure 6(a).

Here, the absolute cathode current density at 1000 rpm is higher in the potential range of about -0.31 V to -0.25 V than the absolute cathode current density obtained at 0 rpm of RDE. Equal in the range of approximately -0.25 V to -0.21 V.

Characterization of copper electrolyte obtained by means of LSV and observation by optical microscopy A good correlation between the cross sections of the samples studied by the method (Fig. 6(b)). The photomicrograph shows the TSV that is not fully filled.

Example 5

The channel filling properties of the acidic copper electrolyte comprising a leveling agent additive suitable for channel filling were determined during the use of the copper electrolyte. Apply the test plan of Table 2.

Data obtained at a high speed of 1000 rpm from RDE at a potential of -210 mV minus the data obtained at a low rotational speed of 0 rpm of RDE, which is within the calculated potential range required for a TSV of a given geometry (Figure 7a).

The resulting data shows a decrease in the curve, which corresponds to a decrease in channel fill properties of the copper electrolyte during use.

A corresponding photomicrograph of the cross section of the sample is shown in Figure 7b, where TSV filling is insufficient after three weeks of electrolyte use. This preferably corresponds to the drop shown in the curve in Figure 7a.

(1) ‧‧‧ channels

(2) ‧‧‧ bottom

(3) ‧‧‧ top

(4) ‧‧‧ channels

(5) ‧ ‧ Center

Figure 1 shows the definition of the TSV type channel and the terms "bottom of the channel" and "top of the substrate surface" (a); and the definition of the TH channel and the term "center of the channel" and "top of the substrate surface" (b) .

Figure 2 shows the range of data in potentiometric values for the current and voltage curves over the range of cathode currents calculated on the bottom of the TSV and on the top of the substrate surface and the current in the cathode current range providing current information on channel fill properties. The correlation between them.

Figure 3 shows the inclusion of a homogenizer in the case of a BMV to be filled. The current-potential curve of the current of the copper electrolyte of the agent at different rotational speeds of the turntable electrode (a); and the corresponding photomicrograph of the cross section of the copper-filled BMV (b).

Figure 4 shows the current-potential curve (a) in the range of the cathode current of the current obtained by the copper electrolyte containing the leveling agent additive at different rotational speeds of the turntable electrode in the case of the BMV to be filled; and the cross section of the copper filled BMV Corresponding photomicrograph (b).

Figure 5 shows the current-potential curve (a) in the range of the cathode current of the current obtained by the copper electrolyte containing the leveling agent additive at different rotational speeds of the turntable electrode in the case of the TSV to be filled; and the cross section of the copper filled TSV Corresponding photomicrograph (b).

Figure 6 shows the current-potential curve (a) in the range of the cathode current of the current obtained by the copper electrolyte containing the leveling agent additive at different rotational speeds of the turntable electrode in the case of the TSV to be filled; and the cross section of the copper filled TSV Corresponding photomicrograph (b).

Figure 7 shows data from a current-potential curve over the range of cathode currents used to characterize the current obtained during TSV filling during the three week plating time for an acid copper electrolyte, showing two different speeds at RDE at -210 mV The ratio of the lower potential to the cathode current value (quotient) is subtracted from each other and plotted against processing time (a); and the corresponding photomicrograph (b) of the cross section of the copper filled TSV.

Claims (9)

A method of monitoring the filling properties of a copper electrolyte, comprising the steps of: a) providing a substrate having at least one channel, b) calculating on the top (3) of the substrate surface at the applied cathode current density a cathode current density value required to completely fill the channel with a metal at a bottom region (2) of the at least one channel of the opening, wherein the desired cathode current density value at the bottom (2) of the channel having an opening is To calculate: [the required cathode current density in the bottom region (2) of the channel] = [Predetermined cathode current density applied to the top (3) of the substrate surface] or calculate the center of the channel having an opening on both sides of the substrate at a predetermined cathode current density on the top (3) of the substrate surface (5) The cathode current density required to conformally fill the channel with metal, wherein the cathode current density value required at the center (5) of the channel having openings on both sides of the substrate is calculated by: The required cathode current density at the center (5) of the channel with openings on both sides of the substrate]= [predetermined cathode current density applied to the top (3) of the substrate surface] and thereby deriving a range of cathode current densities, wherein the effect of the homogenizer additive of the given copper electrolyte and the corresponding decomposition product on the channel filling properties can be obtained, wherein The cathode current density ranges from the cathode current density applied to the surface of the substrate to the cathode current density calculated on the bottom (2) of the channel, wherein the channel is selected from a channel having an opening. And wherein the cathode current density range is between the current density applied to the top of the substrate and the cathode current calculated at the center (5) of the channel if the channel has an opening on both sides of the substrate Within the density range, c) at least two different rotational speeds for the turntable electrode in the three-electrode configuration, the current-voltage curve in the cathodic current range of the current recorded by linear sweep voltammetry, and d) by comparison in step b The current-voltage curve recorded in step c) within the range of cathode current densities obtained from the cathode current density range as calculated in step b) Information in step c) is recorded, the predetermined properties of the obtained copper electrolyte is filled under a predetermined channel geometry of the channel. The method of claim 1, wherein in the step c), the rotational speed of the turntable electrode is between 0 and 100 rpm and the rotational speed of the turntable electrode is greater than 100 rpm. The method of claim 1, wherein the surface of the turntable electrode is composed of copper. The method of claim 1, wherein the scanning speed in step c) is 0.1 Up to 50 mV. A method of monitoring the filling properties of a copper electrolyte, comprising the steps of: a) providing a substrate having at least one channel, b) calculating on the top (3) of the substrate surface at the applied cathode current density a cathode current density value required to completely fill the channel with a metal at a bottom region (2) of the at least one channel of the opening, wherein the desired cathode current density value at the bottom (2) of the channel having an opening is To calculate: [the required cathode current density in the bottom region (2) of the channel] = [Predetermined cathode current density applied to the top (3) of the substrate surface] or calculate the center of the channel having an opening on both sides of the substrate at a predetermined cathode current density on the top (3) of the substrate surface (5) The cathode current density required to conformally fill the channel with metal, wherein the cathode current density value required at the center (5) of the channel having openings on both sides of the substrate is calculated by: The required cathode current density at the center (5) of the channel with openings on both sides of the substrate]= [predetermined cathode current density applied to the top (3) of the substrate surface] and thereby deriving a range of cathode current densities, wherein the effect of the homogenizer additive of the given copper electrolyte and the corresponding decomposition product on the channel filling properties can be obtained, wherein The cathode current density ranges from the cathode current density applied to the surface of the substrate to the cathode current density calculated on the bottom (2) of the channel, wherein the channel is selected from a channel having an opening. And wherein the cathode current density range is between the current density applied to the top of the substrate and the cathode current calculated at the center (5) of the channel if the channel has an opening on both sides of the substrate Within the density range, c) at least two different rotational speeds for the turntable electrode in the three-electrode configuration, the current-voltage curve in the cathodic current range of the current recorded by linear sweep voltammetry, and d) by comparison in step b The current-voltage curve recorded in step c) within the range of cathode current densities obtained from the cathode current density range as calculated in step b) Obtaining the channel filling properties of the predetermined copper electrolyte under a given channel geometry, and e)1 in the case where the channel is selected from the channel having an opening, in step b) Comprising the absolute cathode current at a higher potential at a given potential obtained in step c) within the range of the cathode current density is greater than or equal to the absolute cathode current at the lower temperature at the potential, A leveling agent additive. The method of claim 5, wherein in the step c), the rotational speed of the turntable electrode is between 0 and 100 rpm and the rotational speed of the turntable electrode is greater than 100 rpm. The method of claim 5, wherein the surface of the turntable electrode is composed of copper. The method of claim 5, wherein the scanning speed in step c) is in the range of 0.1 to 50 mV. The method of claim 1 or 5, comprising the further step of: e) 2 in the case where the channel has an opening on both sides of the substrate, the cathode current density range calculated in step b) is in step c) The homogenizer additive is supplemented in the case where the absolute cathode current at the higher rotational speed at the given potential and the absolute cathode current at the lower rotational speed at the potential are different from each other.