JP2000345392A - Copper plating method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the local precipitation of metallic copper in a substrate face by relatively simple equipment and process and to facilitate the flattening of a chemical-mechanical polishing stage, after the passage of a stage in which it is brought into contact with a treating soln. contg. one or more kinds of an organic matter and/or a sulfur compd. contained in a plating soln. for one or more times, by bringing it into contact with the plating soln. and executing plating. SOLUTION: The suitable organic matter is a polyether base organic high molecular polymer, and preferably, the concn. of the treating soln. lies in the range of 10 mg/l to 10 g/l, and the molecular weight of 100 to 100000. As the example, polyethyleneglycol, polypropylene glycol, or the like, is cited. The sulfur compd. is expressed by the general formula: X-L-(S)n-L-X. In the formula, L denotes a lower alkyl group, or the like, and X denotes a compd. of H, an SO3M group or a PO3M group (M denotes H, an alkali metal atom, or the like). As the example, N,N-dimethylthiocarbamylpropylsulfonic acid is cited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an electrolytic copper using a copper sulfate solution for performing wiring by filling copper on the surface of a substrate such as a semiconductor wafer having fine wiring grooves formed on the surface. The present invention relates to a copper plating method for depositing metallic copper by a plating method and an apparatus therefor.

[0002]

2. Description of the Related Art In a conventional electrolytic copper plating process of a substrate using a copper sulfate solution, as a pre-plating process, a substrate to be processed is immersed in sulfuric acid or the like and activated by an acid, or the substrate is treated outside a plating bath. Instead of performing the pretreatment described above, in a plating tank, a copper sulfate solution is brought into contact with a substrate having a seed copper layer as a conductive layer, and after a certain non-energizing time (activation time), energizing is performed to deposit metallic copper. I was trying to make it.

[0003]

However, in the conventional method as described above, in the former method, it is necessary to provide a separate tank for this purpose, and there is a problem that equipment and operating costs increase.

On the other hand, in the latter method, when the plating solution is brought into contact with the substrate, the contact state between the plating solution and the seed copper layer formed on the substrate is not always constant. Uneven adsorption and activation unevenness of the precipitation promoting component and the precipitation suppressing component) on the surface of the seed copper layer are likely to occur. In addition, it is susceptible to specific adsorption of components caused by the black film formed on the surface of the dissolving anode disposed opposite to the substrate. As a result, abnormal precipitation of metallic copper locally occurs on the substrate processing surface, which may give a stain-like appearance. As described above, when the copper is not uniformly deposited locally but abnormally, the crystal orientation of the copper and the copper film thickness become non-uniform, and the copper becomes flat in a post-plating chemical mechanical polishing (CMP) step or the like. Polishing becomes difficult.

[0005] As a countermeasure, various measures have been taken such as prolonging the activation processing time or rotating the substrate or moving the plating solution by means of a device called a squeegee to eliminate uneven adsorption and uneven activation. However, the activation treatment for a long time requires a large amount of etching of the seed copper layer as a fine wiring pattern or an ultra-thin electrode layer at the bottom of a hole with a high aspect ratio, so that the seed layer is completely melted, and the metallic copper is melted. In some cases, it is impossible to embed by plating. Other methods also complicate the equipment,
Or it becomes large.

Further, in the conventional copper plating, there is a problem that the thickness of the copper film to be plated differs depending on the location due to the presence of the wiring pattern. This is a phenomenon in which the plating film thickness in the area where fine wiring is densely increased becomes abnormally thicker than that in the area without wiring. The size of the hump, which is the difference, may reach as much as 1 μm. As described above, when a large hump occurs, chemical mechanical polishing (CM) of a copper film in a later process is performed.
In the P) step and the like, it becomes difficult to polish flat, and the yield of copper is reduced due to an increase in the residual film of copper in a dense portion, which leads to deterioration in yield.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention prevents local deposition of metallic copper on a substrate surface with relatively simple equipment and steps, and achieves planarization in a chemical mechanical polishing step performed after a plating process. Can be made easier,
An object of the present invention is to provide a method and an apparatus for copper plating a substrate such that the appearance of the substrate is finished to a mirror gloss.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In a method for copper plating a substrate, the substrate contains one or more organic substances and / or sulfur compounds contained in a plating solution. A copper plating method for a substrate, characterized in that a step of contacting with a plating solution is performed once or more, and then plating is performed by contacting with a plating solution.

Further, there is provided a method of copper plating a substrate, wherein the contact between the substrate and the treatment liquid is performed before and / or during the plating step. Here, the middle of the plating process means the middle of the deposition of the plating film before reaching the target final plating film thickness.

[0010] In such a copper plating method, before plating, the substrate treatment surface is brought into contact with a treatment solution containing one or more organic substances and / or sulfur compounds contained in the plating solution, or After removing the plating solution from the substrate processing surface on the way, the substrate is brought into contact with the processing solution.

As a method of contacting the substrate with the processing solution,
A method of directly immersing a substrate in a tank filled with a processing liquid, a method of spinning the substrate in a horizontal state at a high speed like a spin drier, and a method of dropping the processing liquid, or a method of setting the substrate in a dedicated chamber for immersion and discharging the processing liquid. There is a method of pumping into the chamber. By such a treatment, the organic substance and / or the sulfur compound is thinly coated on the substrate processing surface in advance. By removing excess processing solution preferably from this substrate and performing copper plating by a conventional method, it is possible to prevent the local abnormal deposition of metallic copper on the substrate processing surface and to achieve a mirror-finished appearance. Plating is performed. Further, the size of the hump in the wiring dense portion in the substrate processing surface can be suppressed.

Performing the draining and / or drying treatment of the substrate processing surface after the above-described treatment is performed in order to minimize the amount of the treatment solution brought into the plating solution and to improve the management of the plating solution. However, it is not always necessary because the amount to be coated is usually much smaller than the amount of the plating solution. As a method of draining, besides simply lowering the liquid level or raising it from the liquid,
There are a method in which the substrate is rotated to shake off the liquid as in a spin dryer, a method in which rotation and nitrogen gas blowing are used in combination, and a method in which the substrate is passed through a strong wind region such as an air towel. Further, the above two steps may be continuously performed by one apparatus, and this may be performed by using a device such as a spin cleaning dryer and rotating while spraying liquid. Thereby, it is possible to achieve both liquid contact and liquid drainage.

The draining may be further advanced to a certain dry state. As a result, the amount of the processing solution brought into the plating solution can be further reduced. In this case, it is preferable to set a semi-dry state containing a certain amount of moisture, rather than a completely dried state.

Although the mechanism of action of the present invention has not been sufficiently elucidated, the inventors presume as follows. When the organic substance used in the method of the present invention is contained in a copper plating solution, the organic substance firstly brings about a surface-active action and the second
Is known to have an effect of suppressing the precipitation of copper to increase the throwing power. Also, it has been known that sulfur compounds originally have an effect of increasing the precipitation of copper by being contained in a plating solution, making the crystals of the deposited film dense, and increasing the glossiness of the plated film. ing. The organic substance and / or sulfur compound having such an action is thinly coated on the substrate processing surface in advance and / or during the plating process, thereby uniformly promoting or suppressing copper deposition on the entire substrate, and causing a specific abnormality. The effect of suppressing precipitation appears. This effect is the same even after a certain drying step.

Further, an organic substance or a sulfur compound contained in the plating solution mediates between the substrate and the plating solution to improve the wettability between the plating solution and the substrate processing surface. The same applies to the case where the organic substance or the sulfur compound elutes into the plating solution even after a certain drying step. Therefore, it is considered that the wet state between the surface to be processed of the substrate and the plating solution is improved and uniformed over the entire surface, so that uniform and efficient plating can be performed over the entire surface of the substrate. These effects also lead to an improvement in the embedding property of copper into holes and grooves having a high aspect ratio provided on the substrate.

The organic substance suitable for use in the present invention is a so-called polyether-based organic polymer, which is used for copper plating. According to the experience of the inventors in conducting the test, the concentration in the processing solution was 10 mg /
It is preferable that the molecular weight is 1 to 10 g / l and the molecular weight is in the range of 100 to 100,000. Examples of organic substances include polyethylene glycol, polypropylene glycol, polyvinyl alcohol, ethoxylated naphthol, propoxylated naphthol, ethoxylated phenol, propoxylated phenol, polyoxyethylene polyoxypropylene block polymer, ethoxylated nonylphenol, carboxymethyl cellulose, and polyethylene propylene glycol. Can be used. The treatment liquid containing these organic substances is particularly effective as a substrate pretreatment liquid before plating.

The sulfur compound is represented by the general formula: XL- (S)_n-L-X (wherein L is a lower alkyl group, a lower alkoxy group, water
1 carbon atom which may be substituted with an acid group or a halogen atom
X is a hydrogen atom, SO ₃M group, also
Is PO₃M group (M is a hydrogen atom, an alkali metal atom, or
Represents an amino group). This
Treatment solution containing sulfur compounds such as
The effect of accelerating the precipitation of copper and suppressing the hump is great,
The concentration in the processing solution is 0.1 μmol / l to 70 μmol
/ L is particularly effective.

The contact time between the substrate and the processing solution is basically required only to allow the processing solution to come into contact with the entire surface of the substrate. If the time is too long, the power supply layer (seed layer) is chemically damaged. Is usually selected in the range of 3 to 60 seconds. Furthermore, when the treatment liquid is strongly alkaline, hydrolysis of organic substances and sulfur compounds easily proceeds,
If the acidity is too strong, the copper in the seed layer is easily etched, so the pH of the treatment liquid is preferably in the range of 2 to 9. Further, depending on the type of the apparatus, a substrate in a dried or semi-dried state may be required. At that time, the above-described effect does not change even if the substrate is brought into contact with the processing liquid and then dried.

According to another aspect of the present invention, a step of stopping plating and etching a plating film in the middle of the plating step is performed in one step.
After more times, the plating solution is brought into contact with the plating solution again to perform plating. In the case where etching is performed by temporarily interrupting plating during the plating process, an electrolytic etching method in which a current flows in a direction opposite to that of normal plating or a chemical etching method using sulfuric acid or the like is applied as an etching means. Further, after the etching step, the step of contacting with the treatment liquid may be performed once or more, and then the plating liquid may be contacted again to perform plating.

As the current waveform when performing electrolytic etching, both a direct current waveform and a pulse waveform (a so-called PR pulse) can be applied. The amount of etching is proportional to the amount of applied current (the product of the current and the conduction time), and is usually 1 to 30 mA / cm ² as the current density with respect to the substrate.
About 0.5 to 30 seconds are used. The concentration of sulfuric acid used in the chemical etching is desirably about 0.5 to 30%, and the contact time with sulfuric acid is appropriately about 1 to 30 seconds. Sulfuric acid is originally a chemical that is often added to plating solutions.
It has the advantage that it is easy to handle from the viewpoint of composition management of the plating solution. The thickness of the plating film to be etched is usually 1 nm.
The effect is recognized as above, but about 10 to 50 nm is preferable.

In still another aspect of the present invention, there is provided a copper plating apparatus for a substrate, wherein the substrate is brought into contact with a processing solution containing one or more organic substances and / or sulfur compounds contained in the plating solution; A means for performing plating by contacting with a solution.

Further, in a copper plating apparatus for a substrate, means for bringing the substrate into contact with a treatment solution containing one or more organic substances and / or sulfur compounds contained in the plating solution, and contacting the substrate with the plating solution to carry out plating. And a means for etching a plating film deposited on a substrate processing surface.

In these cases, the processing tank for bringing the substrate into contact with the processing liquid may be provided separately from the plating processing tank, or the same tank may be shared. In the case where the substrates are individually provided, it is preferable to provide a transfer device that can arrange the substrates in close proximity and quickly arrange the substrates. When the same tank is used in common, it is preferable to provide a liquid supply channel that can separately supply the processing solution and the plating solution, and a drain channel for replacing the solution. Further, an apparatus for continuously contacting, draining and / or drying the processing liquid by spraying the processing liquid while rotating the substrate to bring the processing liquid into contact with the substrate and then increasing the number of rotations of the substrate. It may be provided.

In addition to the processing tank and the plating tank, a load and / or unload unit for receiving or unloading a substrate, a transport unit for transporting the substrate, a cleaning unit for cleaning the substrate, a drying unit It is also possible to use a unit that combines units and the like to receive a substrate in a clean state and to carry it out.

[0025]

FIG. 1 is a diagram showing an outline of a plating apparatus according to an embodiment of the present invention. The plating apparatus 1 includes a load unit 4 and an unload unit 5 for receiving or unloading a substrate (not shown), such as a semiconductor wafer, which is a material to be processed, and a wafer cassette (not shown) accommodating the substrate. A transfer arm 8 and a traveling transfer arm 9 for transferring the substrates one by one, a coating tank (processing tank) 2 for applying a processing solution to the substrate surface, a plating tank 3 for performing a plating process, and a substrate. It comprises a rough cleaning unit 6 for cleaning and a rinser / dryer 10. The coating tank 2 and the plating tank 3 may be of a type that simultaneously processes a plurality of substrates or a single-wafer type. Further, a dip type in which a plating solution or a processing solution is constantly held or a type in which supply and discharge are repeated each time may be used. In this apparatus, two transfer arms 8 and 9
The transport arm 8 for handling a clean substrate and the traveling transport arm 9 for transporting the substrate for plating or the above-described surface treatment are selectively used.

A method of performing a plating process in the plating apparatus having such a configuration will be described along a processing flow of one substrate (not shown). First, a cassette containing substrates is mounted on the load unit 4. Next, the transfer arm 8
The substrates are taken out one by one from the substrate cassette and transferred to the load stage 7. The substrate is received by the traveling transfer arm 9 and is mounted on the coating tank 2 containing the treatment liquid 12a containing one or more kinds of organic substances or sulfur compounds contained in the copper plating solution. After the substrate is immersed in the processing solution 12a for a predetermined time to perform pre-processing, the pre-processed substrate is taken out of the coating tank 2 by the traveling transfer arm 9, and the substrate is plated with a plating tank containing the plating solution 13. 3 and electroplated with copper.

Further, if necessary, when the size of the hump is to be suppressed, the energization is stopped in the plating bath 3 before the electrolytic copper plating reaches a desired film thickness, and the copper plating is interrupted. When performing electrolytic etching of the deposited copper plating film, after the copper plating is interrupted, a current amount (a product of the current and the energizing time) for a predetermined film thickness is obtained by applying a current in a current direction opposite to that during the plating. Give and etch.

Thereafter, if necessary, the substrate is taken out of the plating bath 3 by the traveling transfer arm 9, and the coating bath containing the processing solution 12b containing at least one organic substance or sulfur compound contained in the copper plating solution. 2 and a coating process is performed by immersing the substrate in the processing liquid 12b for a predetermined time. In this case, the processing solution 12
When the liquid compositions of a and 12b are the same, one of the tanks can also be used. Thereafter, the traveling transfer arm 9 takes out the coated substrate from the coating tank 2,
The substrate is mounted on the plating bath 3 containing the plating solution 13 and electroplating is performed for the remaining film thickness.

After the plating is completed, the traveling transfer arm 9 takes out the plated substrate from the plating tank 3 and mounts it on the rough cleaning unit 6. Here, the first cleaning of the substrate is performed. Next, the transfer arm 8 cleans the substrate
, And transferred to the rinser / dryer 10 for the second cleaning, and drying is performed continuously. The substrate is transferred from the rinser / dryer 10 to the substrate cassette in the unloading unit 5 by the transfer arm 8, is unloaded as a clean plated substrate, and is transferred to the next process such as CMP. In this apparatus, there are a plurality of coating tanks 2 and plating tanks 3, and the transfer arm 8 and the traveling transfer arm 9 are controlled and programmed so as to continuously and efficiently process the substrate. It is a expensive device.

FIG. 2 is a diagram showing an outline of a plating apparatus according to another embodiment of the present invention. The configuration of the present apparatus is almost the same as that of the plating apparatus shown in FIG. 1, except that the rotary processing unit 11 is used for the processing mechanism. The rotation processing unit 11 includes a holding mechanism for rotating the substrate, and a spray nozzle for spraying the processing liquid on the surface of the substrate, whereby the processing liquid is uniformly dispersed on the substrate surface while rotating the substrate. . Thereafter, the supply of the processing liquid is stopped and the substrate rotation speed is increased, so that the liquid removal and the drying of the substrate can be continuously performed. This makes it possible to uniformly and efficiently coat the processing liquid on the surface of the substrate, dry the processing liquid, and apply good plating.

FIG. 3 is a diagram showing an outline of a plating apparatus according to another embodiment of the present invention. The configuration of this apparatus is almost the same as that of the plating apparatus shown in FIG. 2, except that a single transfer arm 8 has a plurality of processing tanks 3, 10, 11, and a load / loader that shares receiving and unloading of substrate cassettes. An unload unit 14 is provided, and the substrates are transported by the transport arm 8, and are unified so as to save space as a whole. This plating apparatus is similar to the previous embodiment in that good copper plating free from abnormal deposition can be efficiently applied to the substrate surface and the substrate can be delivered as a clean plated substrate.

[0032]

[Embodiment 1] An embodiment of a plating process performed by using the above plating apparatus will be specifically described below. The processing conditions are as follows. (1) Treatment liquid polypropylene glycol (PPG, molecular weight 40
0, a concentration of 10 mg / l and 5 g / l) a mixture (PPG: molecular weight 700, concentration 50) with polyethylene glycol (PEG, molecular weight 20,000, concentration 100 mg / l and 10 g / l)
mg / l, PEG: molecular weight 6000, concentration 50 mg /
l)

(2) Substrate to be Used After a thermal oxide film is formed to a thickness of 100 nm on an 8-inch silicon substrate, a p-SiN film as an etching stopper is
0 nm, and then a TEOS oxide film is formed to a thickness of 600 nm.
Formed. After forming a TaN film 20 nm as a barrier metal for copper wiring on this substrate by reactive sputtering, a 150 nm seed layer for copper plating is continuously formed without breaking vacuum by LTS (long throw sputtering).
It was formed by a method. (3) Processing time: immersing the substrate in the processing liquid for 10 seconds

(4) Drying method Spin dryer (rotation speed 3000 / min × 30 seconds, no nitrogen gas blow) (5) Test results A substrate treated with the above-mentioned treatment liquid having an organic substance and a non-treated substrate (Comparative Example) ) Were plated in a single-wafer dip-type plating tank 3. The plating solution was a copper plating solution based on copper sulfate, and the thickness of the copper plating was 500 nm. The appearance and CMP characteristics at this time were as follows.

[Table 1]

Further, as reference data, the concentration of Cu attached to the back surface of the substrate was measured. According to this, the untreated substrate was 5 × 10 ¹² atm / cm ² , whereas the substrates treated with the treatment liquid were all 5 × 10 ¹¹ atm / cm ^2.
/ Cm ² or less. Thus, it was found that the present invention also has an effect of reducing copper contamination on the back surface of the substrate.

Further, in the above embodiment, the dissolution of the portion of the power supply layer having a very thin copper film thickness was suppressed, and as a result, the effect of accelerating the deposition property of plating was recognized. It is considered that this is because the polymer used in the present invention also acts as an inhibitor for dissolving copper in the power supply layer.

[0037]

Example 2 The results of pre-treating a substrate with a treatment solution containing a sulfur compound contained in a plating solution are shown below. (1) Treatment solution N, N-dimethyldithiocarbamylpropylsulfonic acid, concentration: 30 μmol / l

(2) Substrate to be Used After a thermal oxide film is formed to a thickness of 100 nm on an 8-inch silicon substrate, a p-SiN film as an etching stopper is
0 nm, and then TEOS oxide film is
m was formed. A hole pattern having a diameter of 0.25 μm, an aspect ratio = 4, a diameter of 0.5 μm, and an aspect ratio = 2 was formed in the TEOS oxide film by a usual lithography and oxide film etching process. After forming a TaN film 20 nm as a barrier metal for copper wiring on this substrate by reactive sputtering, a 150 nm seed layer for copper plating is continuously formed by LTS (long throw sputtering) without breaking vacuum. did. Subsequently, by supplying a current through this copper seed layer, when performing copper plating based on copper sulfate on the substrate, the substrate was brought into contact with the treatment liquid before starting the copper plating. When,
A plated product was produced without contact.
The copper plating film thickness was 600 nm, and after plating, the embedded state in the hole was observed by a cross-sectional SEM (scanning electron microscope). (3) Processing time: dipping the substrate in the processing solution for 5 seconds (4) Drying method Spin dryer (rotation speed 2000 / min × 30 seconds, no nitrogen gas blow)

(5) Test Results The results are shown in Table 2. For holes having a diameter of 0.5 μm and an aspect ratio of 2, there was no difference between the hole treated with the sulfur compound solution and the hole not treated with the sulfur compound solution.
In the case of the hole having a thickness of 4 μm and the aspect ratio = 4, the one subjected to the sulfur compound solution treatment was buried without voids, whereas the one without the treatment had voids at the bottom of the hole. . This is probably because the sulfur compound solution treatment promoted the deposition of plated copper at the bottom of the hole.

[Table 2]

[0040]

Example 3 The results of pre-treatment of the substrate with a treatment solution containing both an organic substance and a sulfur compound contained in the plating solution are shown below. (1) Treatment liquid Organic substance: mixture of PPG and PEG (PPG: molecular weight 700, concentration 50 mg / l, PEG: molecular weight 6000,
Concentration: 50 mg / l) Sulfur compound: N, N-dimethyldithiocarbamylpropylsulfonic acid, concentration: 70 μmol / l

(2) Substrate to be Used After a thermal oxide film is formed to a thickness of 100 nm on an 8-inch silicon substrate, a p-SiN film 5 as an etching stopper is formed.
0 nm, and then TEOS oxide film is
m was formed. By a usual lithography and oxide film etching process, a hole pattern having a diameter of φ0.20 μm, an aspect ratio = 5, φ0.30 μm, and an aspect ratio = 4 was formed in the TEOS oxide film. After forming a TaN film 20 nm as a barrier metal for copper wiring on this substrate by reactive sputtering, a 150 nm seed layer for copper plating is continuously formed by LTS (long throw sputtering) without breaking vacuum. did. Subsequently, by supplying a current through this copper seed layer, when performing copper plating based on copper sulfate to the substrate, before starting the copper plating, those that were brought into contact with the treatment liquid, A plated product was produced without contact. The copper plating film thickness was 600 nm, and after plating, the embedded state in the hole was observed by a cross-sectional SEM (scanning electron microscope). (3) Processing time: the substrate was rotated on a spin dryer at a rotation speed of 150
(4) Drying method Spin dryer (rotation speed 2000 / min x 30 seconds, no nitrogen gas blow)

(5) Test Results The results are shown in Table 3. For holes with a diameter of 0.3 μm and an aspect ratio of 4, there was no difference between those treated with an organic substance and a sulfur compound solution and those not treated.
For a hole with φ0.2μm, aspect ratio = 5,
The treated one was buried without voids, whereas the untreated one had voids at the bottom of the hole. This is presumably because the organic compound improved the wettability and the throwing power inside the hole, and the sulfur compound promoted the deposition of plated copper at the bottom of the hole.

[Table 3]

[0043]

Example 4 The results of contacting the surface of the copper plating with a treatment solution containing a sulfur compound contained in the copper plating solution or etching the surface of the plated plating film during the course of copper plating are shown below. (1) Substrate to be used After a thermal oxide film is formed to a thickness of 100 nm on an 8-inch silicon substrate, a p-SiN film as an etching stopper is
0 nm, and then TEOS oxide film is
m was formed. By a usual lithography and oxide film etching process, a groove pattern in which grooves having a width of 0.2 μm and an aspect ratio = 3 were arranged in the TEOS oxide film with a space of 0.2 μm was formed. After forming a TaN film 20 nm as a barrier metal for copper wiring on this substrate by reactive sputtering, a 150 nm seed layer for copper plating is continuously formed by LTS (long throw sputtering) without breaking vacuum. did. Subsequently, by supplying a current through this copper seed layer, copper plating based on copper sulfate is performed on the substrate, and the thickness of the copper plating is set to 500 nm (650 n inclusive of the thickness of the copper seed layer).
m).

(2) Treatment 1 When the copper plating film was deposited to a thickness of 100 nm, the copper plating was stopped, the plating solution was removed from the surface of the copper plating film, and the sulfur compounds (N, N) contained in the copper plating solution were removed. -Dimethyldithiocarbamylpropylsulfonic acid, concentration 5m
g / l = 24 μmol / l) was brought into contact with the surface of the copper plating film, and then the surface of the copper plating film was brought into contact with the copper plating solution again, and the remaining 400 nm was deposited by electrolytic copper plating. .

(3) Treatment 2 When the copper plating film was deposited to a thickness of 100 nm, the copper plating was stopped, and the polarity of the electrode for electroplating was reversed so that the copper film was 10 nm (treatment 2-1) and 20 nm (treatment 2- After applying a current amount corresponding to the etching amount of 2) and 30 nm (processing 2-3), the plating solution was removed from the surface of the copper plating film, and the sulfur compound (N, N-dimethyl) contained in the copper plating solution was removed. The surface of the copper plating film was brought into contact with a treatment solution in which dithiocarbamylpropylsulfonic acid (concentration: 5 mg / l = 24 μmol / l) was dissolved. Thereafter, the surface of the copper plating film was again brought into contact with the copper plating solution, the polarity of the electrode was reversed, and the remaining 400 nm was deposited by electrolytic copper plating.

(4) Treatment 3 When the copper plating film is deposited to a thickness of 100 nm, the copper plating is stopped, and the polarity of the electrode for electroplating is reversed, and the copper film is treated to 10 nm (treatment 3-1) and 30 nm (treatment 3- After applying a current amount corresponding to the etching amount of 2), the polarity of the electrode was reversed again, and the remaining 400 nm was deposited by electrolytic copper plating.

(5) Test Result The shape of the groove buried by the copper plating in the substrate prepared by the above method was observed by a cross-sectional SEM, and the copper plating film thickness on the groove pattern and the copper on the large space adjacent to the groove pattern were observed. Table 4 shows the result of examining the difference from the plating film thickness (hump size). In Table 4, a 1000-nm thick copper plating deposited on the groove pattern is shown as a comparative example.

[Table 4]

As described above, the copper plating surface is brought into contact with the treatment solution containing the sulfur compound contained in the copper plating solution only once during the copper plating, or by etching the plated plating film surface. It can be seen that it is possible to significantly reduce the size of a hump that hinders planarization in a chemical mechanical polishing (CMP) step or the like after the plating step.

In this example, a treatment solution containing a sulfur compound contained in the copper plating solution is used, but a treatment solution containing an organic substance contained in the copper plating solution is used. It is the same even if is used.

As described above, in the above embodiment, an example in which plating is performed using copper is shown. However, the present invention can of course be applied to plating of other metals such as silver and gold. is there.

As described above, according to the present invention,
Since abnormal deposition of copper during copper plating of the substrate can be suppressed, plating can be performed with high uniformity of the film thickness within the substrate processing surface and with suppressed hump size. In addition, it is possible to improve the embedding characteristics of copper in the fine wiring and to form a copper wiring free from defects such as voids. As a result,
Polishing by chemical mechanical polishing in a later step is facilitated, and the yield of LSI manufacturing using copper wiring can be improved. Therefore, the present invention has high utility in the semiconductor manufacturing industry, for example, such that LSI manufacturing costs can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a plating apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing an overall configuration of a plating apparatus according to another embodiment of the present invention.

FIG. 3 is a diagram showing an overall configuration of a plating apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating apparatus 2 Coating tank (processing tank) 3 Plating processing tank 4 Load unit 5 Unload unit 6 Rough cleaning unit 7 Load stage 8 Transfer arm 9 Traveling transfer arm 10 Rinser / Drier 11 Rotation processing unit 12a, 12b Treatment liquid 13 Plating Liquid 14 Load / Unload unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mizuki Nagai 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (72) Inventor Ryoichi Kimizuka 1-1-6 Yoshiyukizaka, Fujisawa, Kanagawa Prefecture Yu Yu Ebara (72) Inventor Tetsuro Matsuda 8th Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside of Toshiba Yokohama Office (72) Inventor Naofumi Kaneko 8th Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa F-term in Toshiba Yokohama Office (reference) 4K023 AA19 BA06 CA01 CB05 CB32 4K024 AA09 AB01 AB06 AB08 BA11 BB11 BB12 CA02 DA10 DB10 FA05 GA16

Claims (12)

[Claims] In a method of copper plating a substrate, a step of contacting the substrate with a treatment solution containing at least one kind of an organic substance and / or a sulfur compound contained in a plating solution is performed at least once, and thereafter, the plating solution is mixed with the plating solution. A copper plating method for a substrate, wherein the plating is performed by contacting. 2. The copper plating method for a substrate according to claim 1, wherein the contact between the substrate and the treatment liquid is performed before and / or during the plating step. 3. The method according to claim 1, wherein the plating is performed after the substrate is brought into contact with the treatment solution, drained and / or dried. 4. The organic substance is a so-called polyether organic polymer, and has a concentration of 10% in the treatment liquid.
The copper plating method for a substrate according to claim 1, wherein the molecular weight is in a range of 100,000 to 100,000 in mg / l to 10 g / l. 5. The sulfur compound has a general formula: XL- (S)_n-L-X (wherein L is a lower alkyl group, a lower alkoxy group, water
1 carbon atom which may be substituted with an acid group or a halogen atom
X is a hydrogen atom, SO ₃M group, also
Is PO₃M group (M is a hydrogen atom, an alkali metal atom, or
Represents an amino group)).
The concentration in the physiological solution is 0.1 μmol / l to 70 μmol / l.
The copper of the substrate according to claim 1, wherein
The way. 6. A contact time between the substrate and the processing solution is 3 to 60.
The method of claim 1, wherein the second is a second. 7. The method further comprises the step of stopping plating and etching the plating film during the plating step, wherein the substrate is brought into contact with the treatment liquid at least once and again with the plating liquid to perform plating. The method for plating copper on a substrate according to claim 1. 8. A method of plating a substrate, comprising: performing plating at least once in the middle of a plating step after stopping plating and etching a plating film, and then performing plating again by contacting with a plating solution. Copper plating method. 9. The method according to claim 7, wherein the etching method is electrolytic etching or chemical etching. 10. In a copper plating apparatus for a substrate, means for bringing the substrate into contact with a treatment solution containing one or more organic substances and / or sulfur compounds contained in the plating solution, and contacting the substrate with the plating solution to perform plating. Performing a copper plating apparatus. 11. A copper plating apparatus for a substrate, comprising: means for bringing the substrate into contact with a treatment solution containing one or more organic substances and / or sulfur compounds contained in the plating solution; and bringing the substrate into contact with the plating solution to carry out plating. And a means for etching a plating film deposited on a substrate processing surface. 12. The copper plating apparatus according to claim 10, further comprising means for draining and / or drying the treatment liquid while rotating the substrate, and then contacting with the plating liquid to perform plating. Or the copper plating apparatus according to 11.