JP2004068151A - Plating method of substrate and plating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a defect in a plating film caused by the adsorption of bubbles on the surface to be plated. <P>SOLUTION: The bubbles 105 which are adsorbed on the surface of a copper seed film 104 being the surface to be plated of a substrate 101 are removed by rotating the substrate 101 at a high speed in a plating solution 106. Thereafter, a copper plating film 107 is grown on the copper seed film 104 by rotating the substrate 101 at a low speed in the plating solution 106. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a plating method and a plating apparatus for a substrate, and more particularly to a technique for forming a wiring or the like by an electrolytic plating method.

Conventionally, aluminum has been mainly used as a wiring material of an LSI formed on a semiconductor substrate made of silicon. However, in recent years, as the integration and speed of semiconductor integrated circuits have increased, copper, which has lower resistance than aluminum and high electromigration (EM) resistance, has attracted attention as a wiring material. As a method for forming a copper film, for example, there is an electrolytic plating method as described in Patent Document 1.

Hereinafter, a conventional substrate plating method using an electrolytic plating method will be described with reference to the drawings.

FIGS. 10 (a) to 10 (c) are schematic views showing each step of a conventional substrate plating method.

First, as shown in FIG. 10A, while circulating the plating solution 10, the substrate 11 held in a horizontal state by the substrate holding mechanism 12 is immersed in the plating solution 10, and then a control device (not shown) is used. Then, the substrate 11 is rotated together with the substrate holding mechanism 12 at a rotation speed of 30 rpm. The substrate holding mechanism 12 is provided with an electrode 13 in contact with the plating surface of the substrate 11 and a seal 14 in contact with the plating surface so as to protect the electrode 13 from the plating solution 10.

At this time, as shown in FIGS. 10A and 10B, a bubble 15 having a size of about several tens μm stays below the surface to be plated of the rotating substrate 11, while FIG. As shown in c), the rotation of the substrate 11 and the upward flow 10a of the plating solution 10 cause the bubbles 15 to be expelled from the surface of the substrate 11 to be plated to the outside of the substrate holding mechanism 12. Here, the expulsion of the bubble 15 is completed within one second. Whether or not the expelling of the bubbles 15 has been completed is confirmed by examining a change in the resistance value by a minute current applied when the semiconductor substrate 11 is immersed in the plating solution 10.
JP 2001-316869 A

By the way, when the semiconductor substrate is brought into contact with the plating solution, minute bubbles having a size of about several μm or less are adsorbed on the surface to be plated such as the surface of the seed Cu film. However, according to the conventional plating method and plating apparatus, it is not possible to remove these minute bubbles, so that there is a problem that plating growth is hindered at the bubble-adsorbed portion on the plating target surface during subsequent plating growth.

FIGS. 11 (a), (b), FIGS. 12 (a), (b) and FIGS. 13 (a) to 13 (c) are diagrams for explaining problems in the conventional substrate plating method.

Specifically, as shown in FIG. 11A, after sequentially depositing an interlayer insulating film 22, a TaN barrier film 23, and a Cu seed film 24 on a substrate 21, the substrate 21 is placed on a Cu seed, which is a surface to be plated. When the film 24 is immersed in the plating solution 26 with the surface of the film 24 facing downward, bubbles 25 are adsorbed on the surface of the Cu seed film 24. When plating is performed in this state, the plating film 27 is formed with the air bubbles 25 adsorbed on the surface of the Cu seed film 24, and finally, as shown in FIG. A concave defect (concave type defect) 28 and a void 29 are generated.

Further, as shown in FIG. 12A, when particles 30 are adhered on the Cu seed film 24 at the time when the interlayer insulating film 22, the TaN barrier film 23 and the Cu seed film 24 are deposited on the substrate 21, Causes the following problems. That is, when the substrate 21 is brought into contact with the plating solution 26, the particles 30 serve as nuclei and the bubbles 25 are adsorbed on the surface of the Cu seed film 24. As a result, as shown in FIG. As shown in (), a concave defect 28 and a void 29 occur in the plating film 27.

These defects, specifically, the concave defects 28 and the voids 29 are, for example, wiring portions made of the plating film 27 buried in the insulating film 22 or contact portions made of the plating film 27 buried in holes reaching the lower wiring. And the like, a decrease in reliability such as deterioration of electromigration resistance occurs.

In addition, in the conventional substrate plating method, there may be a problem as shown in FIGS.

As shown in FIG. 13A, a first interlayer insulating film 52 is formed on a substrate 51, and the first interlayer insulating film 52 has a lower layer composed of a TaN barrier film 53 and a Cu plating film 54. Wiring is embedded. Here, in the Cu plating film 54, a dent is formed due to the above-described concave defect or the like. As a result, when the SiN film 55 and the second interlayer insulating film 56 are formed on the first interlayer insulating film 52 including the lower wiring, the surface of the second interlayer insulating film 56 is formed due to the above-mentioned depression. In some cases, the depression 57 may occur.

(4) When such a depression 57 is formed in a region where a wide wiring (upper-layer wiring) is formed, a serious failure is unlikely to occur in a portion where the depression 57 is formed. However, when the depression 57 is transferred to a region other than the upper wiring formation region in the second interlayer insulating film 56, the pattern is formed at the time of lithography for forming the upper wiring groove due to the concave shape of the depression 57. Failure may occur. Alternatively, as shown in FIG. 13B, the following problem occurs when the upper layer wiring 58 including the TaN barrier film 58a and the Cu plating film 58b is embedded in the second interlayer insulating film 56. That is, when the wiring material is polished, the TaN film 59a and the Cu film 59b which are not polished are also buried in the depression 57, thereby causing a short circuit between the wirings in the upper wiring 58, as shown in FIG. Conductive portion 59 is formed. FIG. 13 (c) is a plan view corresponding to FIG. 13 (b). In other words, FIG. 13B is a cross-sectional view taken along line BB ′ of FIG. 13C.

In view of the above, it is an object of the present invention to prevent a defect from occurring in a plating film due to adsorption of bubbles on a surface to be plated.

In order to achieve the above object, the first substrate plating method according to the present invention is based on the premise that a plating process is performed on a substrate by immersing the substrate in a plating solution with the surface to be plated facing downward. Removing the air bubbles adsorbed on the substrate by rotating the substrate at a first rotation speed in the plating solution; and performing the first rotation in the plating solution after the step of removing the air bubbles. Performing a plating process on the substrate by rotating the substrate at a second rotation speed lower than the speed.

According to the first substrate plating method, since the substrate is rotated at a high speed in the plating solution before the plating process is started, most of the air bubbles adsorbed on the substrate can be removed. For this reason, it is possible to avoid the formation of concave defects and voids in the plating film due to the adsorption of bubbles.

Further, the second substrate plating method according to the present invention is based on the premise that the substrate is plated in a plating solution by plating the substrate by immersing the substrate in a plating solution with the surface to be plated facing downward. Before the process, a step of improving the wettability of the surface to be plated is provided.

According to the second substrate plating method, the number of bubbles adsorbed to the substrate when the substrate is immersed in the plating solution is greatly reduced in order to improve the wettability of the substrate to be plated before the substrate is immersed in the plating solution. it can. For this reason, it is possible to avoid the formation of concave defects and voids in the plating film due to the adsorption of bubbles.

According to the present invention, air bubbles are generated in the substrate in order to rotate the substrate at a high speed in the plating solution before starting the plating process, or to improve the wettability of the surface to be plated of the substrate before immersing the substrate in the plating solution. The plating process can be performed on the substrate in a state where the substrate is not adsorbed. Therefore, it is possible to avoid the formation of concave defects and voids in the plating film. For example, when the plating film is a conductive film for wiring, an electronic device that is less likely to cause a short circuit between wirings and has high reliability. Can be manufactured.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings, taking as an example the case of forming a wiring plating film made of Cu, which is a wiring material exhibiting the best effects of the present invention.

It should be noted that the substrate plating methods according to the first to fourth embodiments are characterized in that bubbles 105 generated on the surface of the Cu seed film 104 which is the surface to be plated when the substrate 101 is brought into contact with the plating solution 106 are removed. (See FIGS. 1 and 4 to 6). Here, in the method of each embodiment, the plating solution 106 flows along the surface to be plated by the rotation of the substrate 101, so that the bubbles 105 removed from the surface to be plated are flushed to the peripheral portion of the substrate 101. Therefore, in the substrate plating apparatus used in the method of each embodiment, as described later in detail, the contact angle of the seal 210b of the substrate holding mechanism 210 with the surface to be plated of the substrate 209 exceeds 90 ° (more preferably, 120 °). (The angle is not less than 150 °). In this way, it is possible to prevent air bubbles from staying in the portion of the seal 210b that is in contact with the substrate 209 (see FIG. 8).

(1st Embodiment)
Hereinafter, a substrate plating method according to a first embodiment of the present invention will be described with reference to the drawings.

FIGS. 1A to 1E are cross-sectional views showing each step of the substrate plating method according to the first embodiment. In FIGS. 1A to 1E, the main surface of the substrate on which the wiring and the like are formed is shown in a face-down state.

First, as shown in FIG. 1A, an interlayer insulating film 102, a TaN barrier film 103, and a Cu seed film 104 are sequentially deposited on a substrate 101.

Next, as shown in FIG. 1B, the substrate 101 is held by a substrate holding mechanism (not shown), and the substrate 101 is brought into contact with the plating solution 106 face down using the mechanism. At this time, the bubbles 105 are adsorbed on the surface of the Cu seed film 104 which is the surface to be plated. Here, the bubble 105 is a microscopic particle having a size of about several μm to about 10 μm or less, which is generated due to the effect of oxidation or organic contamination on the surface of the Cu seed film 104 or particles attached to the Cu seed film 104 itself. It is a bubble. That is, the bubble 105 is not a bubble having a size of about several tens μm or more, which is generated due to stirring of the plating tank. In FIG. 1B, the bubbles 105 are shown in an enlarged manner for easy understanding.

Thereafter, as shown in FIG. 1C, while the surface of the Cu seed film 104 is immersed in the plating solution 106, the substrate 101 held by the substrate holding mechanism is rotated at a high speed, whereby bubbles 105 are removed from the Cu seed film. It is desorbed from the surface of the film 104. Here, when the bubble 105 is not removed, that is, when plating growth is continued while the bubble 105 is adsorbed on the substrate 101, plating growth does not occur at the portion of the Cu seed film 104 where the bubble 105 is attached, so that a concave defect or Voids and the like occur (see FIGS. 11A and 11B or FIGS. 12A and 12B).

Specifically, in this embodiment, in order to prevent the occurrence of these defects, the substrate 101 is rotated at a rotation speed (rotation speed) of, for example, 100 rpm or more and 500 rpm or less (more preferably 100 rpm or more and 200 rpm or less). Is rotated, for example, for about 1 to 20 seconds. Since the normal rotation speed of the substrate in the subsequent plating growth step is 10 to 100 rpm (more preferably, not less than 10 rpm and not more than 60 rpm), the substrate in the step (wafer high-speed rotation bubble removal step) shown in FIG. The rotation speed is considerably higher than the normal substrate rotation speed. In the present embodiment, the bubbles 105 can be reliably removed from the substrate 101 by the wafer high-speed rotation bubble removal step.

Subsequently, as shown in FIG. 1D, while the surface of the Cu seed film 104 is immersed in the plating solution 106, the rotation speed of the substrate 101 held by the substrate holding mechanism is reduced to, for example, about 10 to 60 rpm. . At this time, since the bubbles 105 are not present on the surface of the Cu seed film 104, the plating process can be performed on the substrate 101 without generating a concave defect or the like. That is, the highly reliable Cu plating film 107 can be gradually grown on the Cu seed film 104. FIG. 1E shows a state in which the plating growth of the Cu plating film 107 has been completely performed.

As described above, according to the first embodiment, since the substrate 101 is rotated at a high speed in the plating solution 106 before the plating process is started, most of the air bubbles 105 adsorbed on the substrate 101 can be removed. . For this reason, it is possible to avoid the formation of concave defects and voids in the Cu plating film 107 due to the adsorption of the bubbles 105, and it is possible to manufacture a highly reliable electronic device in which short-circuiting between wirings does not easily occur.

Here, a method for forming a Cu wiring having a dual damascene structure according to the method of the present embodiment will be described with reference to FIGS. In FIGS. 2A to 2C, the main surface of the substrate on which the wiring and the like are formed is shown in a face-down state.

First, as shown in FIG. 2A, a first interlayer insulating film 152 is formed on a substrate 151, and a lower wiring 153 composed of a TaN barrier film 153a and a Cu film 153b is formed on the first interlayer insulating film 152. Embed Subsequently, after a second interlayer insulating film 154 is formed on each of the lower wiring 153 and the first interlayer insulating film 152, a hole reaching the lower wiring 153 and a hole for the upper wiring are formed in the second interlayer insulating film 154. A recess consisting of a groove is formed. Thereafter, a TaN barrier film 155 and a Cu seed film 156 are sequentially deposited on the second interlayer insulating film 154 including the concave portion so that the concave portion is partially filled.

Next, as shown in FIG. 2B, after the substrate 151 is immersed face down in a plating solution (not shown), the substrate 151 is subjected to a wafer high-speed rotation bubble removal step of the present embodiment. The plating process is performed on the substrate 151 while reducing the rotation speed of the substrate 151. As a result, a highly reliable Cu plating film 157 can be formed so that the concave portion is completely filled on the Cu seed film 156.

Next, as shown in FIG. 2C, the Cu plating film 157, the Cu seed film 156, and the TaN barrier film 155 outside the concave portion are removed by, for example, a CMP method, thereby electrically connecting the lower wiring 153 to the lower wiring 153. Is formed.

FIG. 3 shows a comparative example in which the wafer high-speed rotation bubble removal step of the present embodiment is not performed in the step shown in FIG. 2B.

As shown in FIG. 3, when the wafer high-speed rotation bubble removal step is not performed, when the substrate 151 is immersed in the plating solution face down, bubbles 158 are adsorbed on the surface of the Cu seed film 156 and remain in that state. The plating growth of the Cu plating film 157 is performed. As a result, for example, the plating growth of the Cu plating film 157 is completed while the concave portion is covered with the bubbles 158, and a serious problem occurs in the dual damascene structure.

In the first embodiment, after the substrate 101 was brought into contact with the plating solution 106, the substrate 101 was rotated to remove the bubbles 105. However, instead of this, the substrate 101 is rotated at a speed higher than the rotation speed in the plating process shown in FIG. 1D, for example, at the same rotation speed as the bubble removal process (wafer high-speed rotation bubble removal step). Alternatively, the substrate 101 may be brought into contact with the plating solution 106.

In addition, in the first embodiment, when performing the bubble removing step, it is preferable that the plating solution 106 is convected (circulated). By doing so, the bubbles 105 can be more reliably flushed from the surface of the substrate 101.

In the first embodiment, when performing the bubble removing step, it is preferable to apply ultrasonic vibration to the plating solution 106. By doing so, the bubbles 105 can be more reliably flushed from the surface of the substrate 101.

In the first embodiment, it is not necessary to apply a voltage (plating current) to the Cu seed film 104 in the bubble removing step. However, during the bubble removing step, the thin Cu seed film 104 (particularly, formed in the concave portion) is used. In order to prevent the (part) from being dissolved in the plating solution 106, the bubble removing step may be performed while applying a weak voltage to the substrate 101. At this time, it is desirable that the magnitude of the voltage applied to the substrate 101 is such that the plating current density on the substrate 101 is in the range of 0.1 to 5.0 mA / cm ² . The normal plating current density of the substrate during the plating process is about 10 mA / cm ² or more.

In addition, in the first embodiment, the substrate 101 was brought into contact with the plating solution 106, and subsequently, a bubble removing step by high-speed substrate rotation was performed. However, when the high-speed substrate rotation causes a problem in embedding the plating film in the fine opening (for example, the concave portion having the smallest diameter among the concave portions present on the surface to be plated), after the substrate 101 is brought into contact with the plating solution 106, Alternatively, the plating film may be buried in the fine openings, and then a bubble removing step may be performed. By doing so, it is possible to achieve both the embedding of the plating film into the fine openings such as the minute holes and the removal of bubbles. At this time, the thickness of the plating film necessary for embedding the fine opening is 0.08 μm or less, for example, assuming that the opening diameter of the fine opening is 0.16 μm. Further, it is preferable that the thickness of the plating film necessary for filling the fine opening is 20% or less of the final thickness (target thickness) of the plating film at the time of completion of the plating growth. Further, the substrate rotation speed at the time of embedding the fine opening is lower than the substrate rotation speed in the bubble removal step (wafer high-speed rotation bubble removal step), for example, the substrate rotation speed in the plating step shown in FIG. Preferably, the number of substrate rotations is approximately the same as the number.

In addition, the first embodiment is directed to a case where a wiring plating film made of Cu is formed. However, it goes without saying that the present embodiment can be applied to a case where a plating film made of another material is formed for another use.

(Second embodiment)
Hereinafter, a substrate plating method according to a second embodiment of the present invention will be described with reference to the drawings.

FIGS. 4A to 4E are cross-sectional views showing each step of the substrate plating method according to the second embodiment. In FIGS. 4A to 4E, the main surface of the substrate on which the wiring and the like are formed is shown in a face-down state.

First, as shown in FIG. 4A, an interlayer insulating film 102, a TaN barrier film 103, and a Cu seed film 104 are sequentially deposited on a substrate 101.

Thereafter, in the present embodiment, while holding the substrate 101 face down in a substrate holding mechanism (not shown), the pure water spray nozzle 111 applies a pure water shower to the surface of the Cu seed film 104 that is the surface to be plated. Inject 112.

By the way, if no special treatment is performed after the deposition of the Cu seed film 104 as in a normal plating process, the surface of the Cu seed film 104 may be oxidized or may be affected by organic contamination from the substrate cassette or the surrounding atmosphere. As a result, the wettability of the surface of the Cu seed film 104 with the plating solution 106 (see FIG. 4C) is deteriorated. On the other hand, in the present embodiment, before the substrate 101 is immersed in the plating solution 106, the surface of the Cu seed layer 104 is wetted in advance with pure water 113 (see FIG. 4B). Surface wettability can be improved.

Specifically, as shown in FIG. 4B, the surface of the Cu seed film 104 is wet by spraying pure water 113 on the surface of the Cu seed film 104, and as a result, the substrate 101 is plated with the plating solution 106. The number of bubbles 105 (see FIG. 4C) adsorbed on the surface of the Cu seed film 104 when immersed in the substrate is reduced.

However, when the pure water 113 is sprayed on the surface of the Cu seed film 104, relatively large bubbles 114 are generated in the pure water 113 attached to the surface of the Cu seed film 104. That is, in the present embodiment, although the total number of bubbles adsorbed on the surface of the Cu seed film 104 is reduced when the substrate 101 is immersed in the plating solution 106, the bubbles 114 having a size exceeding several μm at this time are reduced. May remain on the surface of the Cu seed film 104 in some cases.

Then, next, as shown in FIG. 4C, the substrate 101 is brought into contact with the plating solution 106 face down using the substrate holding mechanism, and then, as shown in FIG. Is rotated at high speed. As a result, by the centrifugal force generated by the rotation of the substrate 101, the minute bubbles 105 generated when the substrate 101 is brought into contact with the plating solution 106 can be detached from the surface of the Cu seed film 104, and the Cu seed film 104 can be removed. Large bubbles 114 generated when pure water 113 is sprayed on the surface of 104 can also be removed. In FIGS. 4B and 4C, the bubbles 105 and 114 are enlarged for easy understanding.

Here, in the process shown in FIG. 4D (wafer high-speed rotation bubble removal step), the substrate 101 is rotated at a rotation speed (rotation speed) of, for example, 100 rpm or more and 500 rpm or less (more preferably 100 rpm or more and 200 rpm or less). For example, it is rotated for about 1 to 20 seconds. Since the normal substrate rotation speed in the subsequent plating growth step is 10 to 100 rpm (more preferably, 10 rpm or more and 60 rpm or less), the substrate rotation speed in the wafer high-speed rotation bubble removal step is equal to the normal substrate rotation speed. It is much faster than that.

Subsequently, while the surface of the Cu seed film 104 is immersed in the plating solution 106, the rotation speed of the substrate 101 held by the substrate holding mechanism is reduced to, for example, about 10 to 60 rpm, thereby performing a plating growth (plating process) step. Is carried out. At this time, since the bubbles 105 and the bubbles 114 are detached from the surface of the Cu seed film 104 by the wafer high-speed rotation bubble removal step, the plating process on the substrate 101 can be performed without generating a concave defect or the like. Can be. That is, the highly reliable Cu plating film 107 can be gradually grown on the Cu seed film 104. FIG. 4E shows a state where the plating growth of the Cu plating film 107 is completely performed.

As described above, according to the second embodiment, before the substrate 101 is immersed in the plating solution 106, the surface of the Cu seed film 104, which is the plating target surface of the substrate 101, is improved in wettability. The number of bubbles 105 adsorbed on the substrate 101 when the substrate 101 is immersed in the plating solution 106 can be greatly reduced. Further, since the substrate 101 is rotated at a high speed in the plating solution 106 before the plating process is started, most of the bubbles 105 and 114 adsorbed on the substrate 101 can be removed. Therefore, it is possible to avoid the formation of a concave defect or a void in the Cu plating film 107 due to the adsorption of the bubbles 105 and 114, and to manufacture a highly reliable electronic device in which a short circuit between wirings does not easily occur. it can.

In the second embodiment, after the substrate 101 was brought into contact with the plating solution 106, the substrate 101 was rotated to remove the bubbles 105 and 114. However, instead of this, while rotating the substrate 101 at a speed higher than the rotation speed in the plating process, for example, at the same rotation speed as the bubble removal process (wafer high-speed rotation bubble removal step), the substrate 101 is plated with the plating solution 106. May be in contact with the liquid.

In the second embodiment, when performing the bubble removing step, it is preferable that the plating solution 106 be convected (circulated). By doing so, the bubbles 105 and 114 can be more reliably flushed from the surface of the substrate 101.

In the second embodiment, when performing the bubble removing step, it is preferable to apply ultrasonic vibration to the plating solution 106. By doing so, the bubbles 105 and 114 can be more reliably flushed from the surface of the substrate 101.

In the second embodiment, it is not necessary to apply a voltage (plating current) to the Cu seed film 104 in the bubble removing step. However, during the bubble removing step, the thin Cu seed film 104 (particularly, formed in the concave portion) is used. In order to prevent the (part) from being dissolved in the plating solution 106, the bubble removing step may be performed while applying a weak voltage to the substrate 101. At this time, it is desirable that the magnitude of the voltage applied to the substrate 101 is such that the plating current density on the substrate 101 is in the range of 0.1 to 5.0 mA / cm ² . The normal plating current density of the substrate during the plating process is about 10 mA / cm ² or more.

Further, in the second embodiment, before the substrate 101 is immersed in the plating solution 106, the pure water jet nozzle 111 is used to improve the wettability of the surface to be plated of the substrate 101 (the surface of the Cu seed film 104). Pure water 113 was supplied to the surface to be plated. However, instead of this, another liquid may be supplied to the surface to be plated using another supply mechanism.

In addition, in the second embodiment, the substrate 101 was brought into contact with the plating solution 106, and subsequently, a bubble removing step by high-speed substrate rotation was performed. However, when the high-speed substrate rotation causes a problem in embedding the plating film in the fine opening (for example, the concave portion having the smallest diameter among the concave portions present on the surface to be plated), after the substrate 101 is brought into contact with the plating solution 106, Alternatively, the plating film may be buried in the fine openings, and then a bubble removing step may be performed. By doing so, it is possible to achieve both the embedding of the plating film into the fine openings such as the minute holes and the removal of bubbles. At this time, the thickness of the plating film necessary for embedding the fine opening is 0.08 μm or less, for example, assuming that the opening diameter of the fine opening is 0.16 μm. Further, it is preferable that the thickness of the plating film necessary for filling the fine opening is 20% or less of the final thickness (target thickness) of the plating film at the time of completion of the plating growth. Also, the substrate rotation speed at the time of embedding the fine opening is lower than the substrate rotation speed in the bubble removal step (wafer high-speed rotation bubble removal step), for example, the same substrate rotation speed as the substrate rotation speed in the plating process. It is preferably a number.

In the second embodiment, the bubble removing step shown in FIG. 4D may be omitted.

In the second embodiment, the case where a wiring plating film made of Cu is formed is intended. However, it goes without saying that the present embodiment can be applied to a case where a plating film made of another material is formed for another use.

(Third embodiment)
Hereinafter, a substrate plating method according to a third embodiment of the present invention will be described with reference to the drawings.

FIGS. 5A to 5E are cross-sectional views showing each step of the substrate plating method according to the third embodiment. In FIGS. 5A to 5E, the main surface of the substrate on which the wiring and the like are formed is shown in a face-down state.

First, as shown in FIG. 5A, an interlayer insulating film 102, a TaN barrier film 103, and a Cu seed film 104 are sequentially deposited on a substrate 101. At this time, particles 115 such as Cu generated during the deposition of the Cu seed film 104 adhere to the surface of the Cu seed film 104. When the substrate 101 is immersed in a plating solution in a state where the particles 115 are present on the surface of the Cu seed film 104, bubbles are generated with the particles 115 as nuclei, thereby causing defects in the plating film.

Therefore, as a feature of the present embodiment, after the Cu seed film 104 is deposited, the substrate 101 is held face down in a substrate holding mechanism (not shown), and the surface of the Cu seed film 104, which is the plating surface, is Then, an ultrasonic vibration applying pure water shower 117 is injected from the ultrasonic vibration applying pure water injection nozzle 116. The ultrasonic vibration applied pure water shower 117 is sprayed over the entire surface of the substrate 101. As a result, as shown in FIG. 5B, the particles 115 attached to the surface of the Cu seed film 104 can be removed. Therefore, when the substrate 101 is immersed in the plating solution, the generation of air bubbles with the particles 115 as nuclei can be suppressed, so that a situation in which a concave defect, a void, or the like is formed in the plating film can be avoided.

In the step shown in FIG. 5A, the particles 115 are removed by applying ultrasonic vibration to the surface of the Cu seed film 104, which is the surface to be plated, and at the same time, pure water is sprayed on the surface of the Cu seed film 104. Thereby, the wettability of the surface with the plating solution is also improved. As a result, when the substrate 101 is immersed in the plating solution, the number of minute bubbles adsorbed on the surface of the Cu seed film 104 is further reduced. However, when cleaning the surface of the Cu seed film 104 with the pure water to which the ultrasonic vibration is applied, relatively large bubbles may adhere to the surface.

Then, as shown in FIG. 5C, the surface of the Cu seed film 104 of the substrate 101 held face down by the substrate holding mechanism is brought into contact with the plating solution 106, and then, as shown in FIG. As shown in d), the substrate 101 held by the mechanism is rotated at high speed. As a result, the microbubbles 105 generated when the substrate 101 is brought into contact with the plating solution 106 can be detached from the surface of the Cu seed film 104 by the centrifugal force generated by the rotation of the substrate 101, and the ultrasonic vibration Large bubbles generated when pure water to which is applied is sprayed onto the surface of the Cu seed film 104 can be removed. In FIG. 5C, the bubbles 105 are shown in an enlarged manner for easy understanding.

Here, in the step (wafer high-speed rotation bubble removal step) shown in FIG. 5D, the substrate 101 is rotated at a rotation speed (rotation speed) of, for example, 100 rpm or more and 500 rpm or less (more preferably 100 rpm or more and 200 rpm or less). For example, it is rotated for about 1 to 20 seconds. Since the normal substrate rotation speed in the subsequent plating growth step is 10 to 100 rpm (more preferably, 10 rpm or more and 60 rpm or less), the substrate rotation speed in the wafer high-speed rotation bubble removal step is equal to the normal substrate rotation speed. It is much faster than that.

Subsequently, while the surface of the Cu seed film 104 is immersed in the plating solution 106, the rotation speed of the substrate 101 held by the substrate holding mechanism is reduced to, for example, about 10 to 60 rpm, and then an electric field is applied to the plating solution 106. A plating growth (plating process) step is performed according to a normal plating method. At this time, since the bubbles 105 and the like are desorbed from the surface of the Cu seed film 104 by the wafer high-speed rotation bubble removal step, the plating process on the substrate 101 can be performed without generating a concave defect or a void. it can. That is, the highly reliable Cu plating film 107 can be gradually grown on the Cu seed film 104. FIG. 5E shows a state in which the plating growth of the Cu plating film 107 has been completed.

As described above, according to the third embodiment, before immersing the substrate 101 in the plating solution 106, the particles 115 attached to the surface of the Cu seed film 104, which is the surface to be plated of the substrate 101, are removed. In addition, the number of bubbles adsorbed on the substrate 101 when the substrate 101 is immersed in the plating solution 106 can be greatly reduced in order to improve the wettability of the surface. Further, since the substrate 101 is rotated at a high speed in the plating solution 106 before the plating process is started, most of the air bubbles adsorbed on the substrate 101 can be removed. For this reason, it is possible to avoid the formation of concave defects and voids in the Cu plating film 107 due to the adsorption of bubbles, and it is possible to manufacture a highly reliable electronic device in which a short circuit between wirings does not easily occur.

In the third embodiment, after the substrate 101 was brought into contact with the plating solution 106, the substrate 101 was rotated to remove bubbles. However, instead of this, while rotating the substrate 101 at a speed higher than the rotation speed in the plating process, for example, at the same rotation speed as the bubble removal process (wafer high-speed rotation bubble removal step), the substrate 101 is plated with the plating solution 106. May be in contact with the liquid.

In the third embodiment, when performing the air bubble removing step, it is preferable that the plating solution 106 be convected (circulated). By doing so, bubbles can be more reliably flushed from the surface of the substrate 101.

In the third embodiment, when performing the bubble removing step, it is preferable to apply ultrasonic vibration to the plating solution 106. By doing so, bubbles can be more reliably flushed from the surface of the substrate 101.

In the third embodiment, it is not necessary to apply a voltage (plating current) to the Cu seed film 104 in the bubble removing step. However, during the bubble removing step, the thin Cu seed film 104 (particularly, formed in the concave portion) is used. In order to prevent the (part) from being dissolved in the plating solution 106, the bubble removing step may be performed while applying a weak voltage to the substrate 101. At this time, it is desirable that the magnitude of the voltage applied to the substrate 101 is such that the plating current density on the substrate 101 is in the range of 0.1 to 5.0 mA / cm ² . The normal plating current density of the substrate during the plating process is about 10 mA / cm ² or more.

Further, in the third embodiment, before the substrate 101 is immersed in the plating solution 106, the surface of the Cu seed film 104, which is the surface to be plated, is removed in order to remove particles 115 attached to the surface. Ultrasonic vibration was applied. However, in the present embodiment, the method for removing the particles 115 is not particularly limited. Although pure water is supplied to the surface to be plated in order to improve the wettability of the surface to be plated, another liquid may be supplied to the surface to be plated instead. At this time, ultrasonic vibration may be applied to the other liquid.

Also, in the third embodiment, the substrate 101 was brought into contact with the plating solution 106, and subsequently, a bubble removing step by high-speed substrate rotation was performed. However, when the high-speed substrate rotation causes a problem in embedding the plating film in the fine opening (for example, the concave portion having the smallest diameter among the concave portions present on the surface to be plated), after the substrate 101 is brought into contact with the plating solution 106, Alternatively, the plating film may be buried in the fine openings, and then a bubble removing step may be performed. By doing so, it is possible to achieve both the embedding of the plating film into the fine openings such as the minute holes and the removal of bubbles. At this time, the thickness of the plating film necessary for embedding the fine opening is 0.08 μm or less, for example, assuming that the opening diameter of the fine opening is 0.16 μm. Further, it is preferable that the thickness of the plating film necessary for filling the fine opening is 20% or less of the final thickness (target thickness) of the plating film at the time of completion of the plating growth. Also, the substrate rotation speed at the time of embedding the fine opening is lower than the substrate rotation speed in the bubble removal step (wafer high-speed rotation bubble removal step), for example, the same substrate rotation speed as the substrate rotation speed in the plating process. It is preferably a number.

(5) In the third embodiment, the bubble removing step shown in FIG. 5D may be omitted.

In addition, the third embodiment is directed to a case where a wiring plating film made of Cu is formed. However, it goes without saying that the present embodiment can be applied to a case where a plating film made of another material is formed for another use.

(Fourth embodiment)
Hereinafter, a substrate plating method according to a fourth embodiment of the present invention will be described with reference to the drawings.

6 (a) to 6 (e) are cross-sectional views showing each step of the substrate plating method according to the fourth embodiment. In FIGS. 6A to 6E, the main surface of the substrate on which the wiring and the like are formed is shown in a face-down state.

First, as shown in FIG. 6A, an interlayer insulating film 102, a TaN barrier film 103, and a Cu seed film 104 are sequentially deposited on a substrate 101.

Next, as shown in FIG. 6B, the substrate 101 is held by a substrate holding mechanism (not shown), and the substrate 101 is brought into contact with the plating solution 106 face down using the mechanism. At this time, the bubbles 105 are adsorbed on the surface of the Cu seed film 104 which is the surface to be plated. The plating solution 106 is stored in a plating bath (not shown) to which an ultrasonic vibration generator 118 is attached.

Then, as shown in FIG. 6C, ultrasonic vibration is applied to the plating solution 106 by the ultrasonic vibration generator 118 while the surface of the Cu seed film 104 is immersed in the plating solution 106. The step (bubble removing step) shown in FIG. 6C is a feature of the present embodiment, whereby the bubbles 105 adsorbed on the surface of the Cu seed film 104 can be removed. At this time, the bubbles 105 are removed by performing the same wafer high-speed rotation bubble removal step as in the first to third embodiments, that is, by rotating the substrate 101 held by the substrate holding mechanism at a high speed. The effect can be further improved. 6 (b) and 6 (c), the bubble 105 is shown in an enlarged manner for easy understanding.

Next, as shown in FIG. 6D, a normal plating process is performed on the substrate 101, so that a Cu plating film 107 is gradually grown on the Cu seed film 104. FIG. 6E shows a state in which the plating growth of the Cu plating film 107 has been completed.

As described above, according to the fourth embodiment, the ultrasonic vibration is applied to the plating solution 106 in which the substrate 101 is immersed before the plating process is started, so that the small bubbles 105 attached to the substrate 101 are removed. can do. For this reason, it is possible to avoid the formation of concave defects and voids in the Cu plating film 107 due to the adsorption of the bubbles 105, and it is possible to manufacture a highly reliable electronic device in which short-circuiting between wirings does not easily occur.

In the fourth embodiment, when performing the air bubble removing step, it is preferable that the plating solution 106 be convected (circulated). By doing so, bubbles can be more reliably flushed from the surface of the substrate 101.

In the fourth embodiment, when an electrode containing Cu as a main component is used as the anode electrode attached to the plating bath in which the plating solution 106 is stored, by applying ultrasonic vibration to the plating solution 106, Particles may be generated from the anode electrode. In order to prevent this, it is preferable to use a material that does not substantially dissolve in the plating solution 106, for example, platinum or the like, as the material of the anode electrode. However, in this case, it is necessary to separately supply a Cu component to the plating solution 106 in order to compensate for a decrease in the Cu concentration in the plating solution 106 due to the Cu plating process.

Further, in the fourth embodiment, before the substrate 101 is brought into contact with the plating solution 106, for example, pure water is supplied to the surface of the Cu seed film 104, which is the surface to be plated, as in the second embodiment, Thereby, it is preferable to improve the wettability of the surface to be plated. At this time, similarly to the third embodiment, it is more preferable to remove the particles adhering to the surface to be plated by supplying ultrasonic vibration to pure water, for example. It should be noted that even the large bubbles generated when pure water is sprayed on the surface of the Cu seed film 104, the small bubbles adhering to the surface of the Cu seed film 104 by using the ultrasonic vibration generator 118 of the present embodiment. 105 can be removed.

In the fourth embodiment, it is not necessary to apply a voltage to each electrode in the bubble removing step by applying ultrasonic waves. In other words, it is not necessary to apply a voltage (plating current) to the Cu seed film 104. However, in order to prevent the thin Cu seed film 104 from being dissolved in the plating solution 106 during the bubble removing step, the bubble removing step may be performed while applying a weak voltage to the substrate 101. At this time, it is desirable that the magnitude of the voltage applied to the substrate 101 is such that the plating current density on the substrate 101 is in the range of 0.1 to 5.0 mA / cm ² . The normal plating current density of the substrate during the plating process is about 10 mA / cm ² or more.

In addition, in the fourth embodiment, the substrate 101 was brought into contact with the plating solution 106, and subsequently, a bubble removing step by applying ultrasonic waves was performed. However, if the ultrasonic vibration causes a problem in embedding the plating film in the fine opening (for example, at least the concave portion having the smallest diameter among the concave portions present on the surface to be plated), after the substrate 101 is brought into contact with the plating solution 106, Alternatively, the plating film may be buried in the fine openings, and then a bubble removing step may be performed. By doing so, it is possible to achieve both the embedding of the plating film into the fine openings such as the minute holes and the removal of bubbles. At this time, the thickness of the plating film necessary for embedding the fine opening is 0.08 μm or less, for example, assuming that the opening diameter of the fine opening is 0.16 μm. Further, it is preferable that the thickness of the plating film necessary for filling the fine opening is 20% or less of the final thickness (target thickness) of the plating film at the time of completion of the plating growth.

(4) In the fourth embodiment, the case where a wiring plating film made of Cu is formed is intended. However, it goes without saying that the present embodiment can be applied to a case where a plating film made of another material is formed for another use.

(Fifth embodiment)
Hereinafter, a substrate plating apparatus according to a fifth embodiment of the present invention will be described with reference to the drawings.

FIGS. 7A and 7B are schematic diagrams illustrating a configuration of a substrate plating apparatus according to a fifth embodiment, in which FIG. 7A illustrates a state before the substrate is immersed in a plating solution, and FIG. () Shows a state after the substrate is immersed in the plating solution.

The plating apparatus of the present embodiment has a plating solution tank 201 for storing a plating solution 200 as shown in FIGS. 7A and 7B. The plating solution 200 is sent from a plating solution tank 201 to a plating bath 204 via a pump 202 and a filter 203.

ア ノ ー ド In the plating bath 204, an anode electrode 205 and a rectifying plate 206 are provided. As one of the features of the present embodiment, an ultrasonic vibration generator 207 for applying ultrasonic vibration to the plating solution 200 is provided in the plating bath 204. Further, a plating solution recovery tank 208 is provided outside the plating bath 204, whereby the plating solution 200 overflowing from the plating bath 204 can be returned to the plating solution tank 201 and used repeatedly. That is, the plating apparatus of the present embodiment has a plating solution circulation mechanism for circulating the plating solution 200 between the plating solution tank 201 and the plating bath 204.

A substrate holding mechanism 210 is provided above the plating bath 204 for holding the substrate 209 and immersing the substrate 209 in the plating solution 200 stored in the plating bath 204 so that the surface to be plated faces downward. The substrate holding mechanism 210 can rotate while holding the substrate 209.

FIG. 8 is an enlarged view of a portion supporting the substrate 209 in the substrate holding mechanism 210. As shown in FIG. 8, the substrate holding mechanism 210 includes a cathode electrode 210a in contact with the plating surface of the substrate 209 and a seal 210b in contact with the plating surface of the substrate 209 so as to protect the cathode electrode 210a from the plating solution 200. Is provided. That is, as shown in FIG. 7B, in a state where the substrate 209 is immersed in the plating solution 200 stored in the plating bath 204, the substrate 209 is placed between the anode electrode 205 and the cathode electrode 210a, that is, between the anode electrode 205 and the substrate 209. By applying a voltage between the substrate and the surface to be plated (for example, the surface of a Cu seed layer), plating can be performed. As one of the features of the present embodiment, the portion of the seal 210b that supports the substrate 209 is not in a positional relationship perpendicular to the plating surface of the substrate 209, but in an inclined positional relationship. In other words, the contact angle of the seal 210b with the surface to be plated of the substrate 209 is larger than 90 ° when viewed from the center side of the substrate 209, and preferably in the range of 120 ° or more and 150 ° or less.

As shown in FIG. 7A, the plating apparatus of the present embodiment is characterized in that pure water or the like to which ultrasonic vibration is applied to the surface to be plated of the substrate 209 outside the plating bath 204 is used. An ultrasonic vibration applying cleaning liquid nozzle 211A capable of supplying a cleaning liquid is provided. Here, instead of the nozzle 211A to which ultrasonic vibration can be applied, a cleaning liquid nozzle 211B that can supply a cleaning liquid in a normal state may be provided. Further, a cleaning waste liquid recovery tank 212 for recovering used cleaning liquid is provided outside the plating bath 204 (exactly outside the plating liquid recovery tank 208). In FIG. 7B showing the state after the substrate 209 is immersed in the plating solution 200, the nozzle 211A or 211B and the cleaning waste liquid collecting tank 212 are omitted.

Hereinafter, effects produced by the features of the present embodiment will be described.

In the present embodiment, an ultrasonic vibration generator 207 for applying ultrasonic vibration to the plating solution 200 is provided in the plating bath 204. Thereby, when the substrate 209 held by the substrate holding mechanism 210 is immersed in the plating solution 200 stored in the plating bath 204, minute air bubbles having a size of several μm or less adsorbed on the substrate 209 are easily removed. be able to.

In the present embodiment, as shown in FIG. 8, the contact angle of the seal 210b with the plating surface of the substrate 209 is larger than 90 °. By the way, as in the conventional structure shown in FIG. 9, the contact angle of the seal 210b with the surface to be plated of the substrate 209 is 90 °, in other words, the portion of the seal 210b supporting the substrate 209 is the surface of the substrate 209 to be plated. The following problem arises when it is in contact with the vertical. That is, when removing the air bubbles attached to the surface of the substrate 209, for example, a part of the air bubbles that have been washed away by the plating solution 200 accumulates at the corner formed by the contact between the seal 210 b and the substrate 209. As a result, bubbles cannot be sufficiently removed from the surface of the substrate 209 to be plated. On the other hand, in the present embodiment, as shown in FIG. 8, the contact angle of the seal 210b with the surface to be plated of the substrate 209 is larger than 90 °, and the contact portion between the seal 210b and the substrate 209 has a gentle bottom. Has an expanded shape. Therefore, by rotation of the substrate holding mechanism 210 described in the first to third embodiments, convection of the plating solution 200 in the plating bath 204, or application of ultrasonic vibration to the plating solution 200 described in the fourth embodiment, Bubbles blown out of the surface to be plated of the substrate 209 do not accumulate in the contact portion (corner) between the seal 210b and the substrate 209 as in the related art. As a result, bubbles can be easily removed from the surface of the substrate 209 to be plated.

In the present embodiment, before the substrate 209 is immersed in the plating solution 200 stored in the plating bath 204, for example, pure water (or pure water to which ultrasonic vibration is applied) is applied to the surface to be plated of the substrate 209. A nozzle 211A or 211B for supplying water) is provided. For this reason, the wettability of the surface to be plated of the substrate 209 can be improved, or particles adhering to the surface to be plated can be removed, so that when the substrate 209 is immersed in the plating solution 200, it is adsorbed to the substrate 209. The number of generated bubbles can be greatly reduced.

Hereinafter, the operation of the plating apparatus of the present embodiment when performing the plating method according to the first to fourth embodiments will be described with reference to FIGS. 7 (a) and 7 (b).

First, the substrate 209 is mounted on the substrate holding mechanism 210. After that, in the case of the first or fourth embodiment, the substrate 209 is directly contacted with the plating solution 200 stored in the plating bath 204 by using the substrate holding mechanism 210, and the second embodiment or the third embodiment is used. In this case, after performing a pretreatment described later on the substrate 209, the substrate 209 is brought into contact with the plating solution 200 as in the first or fourth embodiment. For this pretreatment, an apparatus provided with a mechanism (for example, a cleaning liquid nozzle or the like) capable of spraying a liquid to the substrate 209 is used. Thereafter, the substrate 209 is rotated using the substrate holding mechanism 210 and a voltage is applied to the substrate 209, thereby forming a plating film. In the case of the first embodiment, before applying a voltage for the plating process, the substrate 209 is rotated in the plating solution 200 using the substrate holding mechanism 210 at a rotation speed higher than the rotation speed during the plating process. Rotate with. In the case of the fourth embodiment, the ultrasonic vibration generator 207 is used while rotating the substrate 209 using the substrate holding mechanism 210 in the plating solution 200 before applying the voltage for the plating process. Then, ultrasonic vibration is applied to the plating solution 200 stored in the plating bath 204.

Here, the pre-processing in the second or third embodiment will be described.

In the second embodiment, for example, pure water or the like is sprayed onto the substrate 209 using the cleaning liquid nozzle 211B before the substrate 209 is brought into contact with the plating solution 200. In the third embodiment, for example, pure water or the like to which ultrasonic vibration is applied is sprayed onto the substrate 209 by using the ultrasonic vibration applying cleaning liquid nozzle 211A. Thereby, in each of the embodiments, the effect that the wettability of the surface to be plated of the substrate 209 can be improved is obtained, and in the third embodiment, the substrate 209 is further brought into contact with the plating solution 200. Particles attached to the surface of the substrate 209, which serve as nuclei for bubble generation, can be removed. In the second or third embodiment, when the substrate 209 is rotated or moved up and down using the substrate holding mechanism 210 at the time of cleaning using the nozzle 211A or 211B, the cleaning effect is further improved. be able to. Further, when air bubbles adhere to the surface of the substrate 209 due to the injection of the cleaning solution such as pure water, the substrate 209 is rapidly moved in the plating solution 200 stored in the plating bath 204 before the plating process is started. By rotating, air bubbles can be removed.

As described above, according to the plating apparatus of the present embodiment, plating is performed on the substrate 209 after removing the air bubbles adsorbed on the surface of the substrate 209 or in a state where no air bubbles are attached to the surface of the substrate 209. Processing can be performed. For this reason, it is possible to prevent the formation of concave defects and voids in the plating film due to the adsorption of bubbles, so that a uniform plating film can be obtained. Therefore, for example, when the plating film is a conductive film for wiring, it is possible to manufacture an electronic device that hardly causes a short circuit between wirings and has high reliability.

In this embodiment, as in the fourth embodiment, when an electrode containing Cu as a main component is used as the anode electrode 205 attached to the plating bath 204 in which the plating solution 200 is stored, the plating solution There is a possibility that particles may be generated from the anode electrode 205 by applying the ultrasonic vibration to 200. In order to prevent this, it is preferable to use a material that does not substantially dissolve in the plating solution 200, for example, platinum or the like, as the material of the anode electrode 205. However, in this case, it is necessary to separately supply a Cu component to the plating solution 200 in order to compensate for a decrease in the Cu concentration in the plating solution 200 due to the Cu plating process.

Also, in the present embodiment, the nozzle 211A or 211B is used to supply a liquid such as pure water to the surface to be plated of the substrate 209, but such a liquid supply mechanism is not particularly limited.

In this embodiment, the case where a wiring plating film made of Cu is formed is intended. However, it goes without saying that the present embodiment can be applied to a case where a plating film made of another material is formed for another use.

As described above, the plating method and the plating apparatus according to the present invention have an effect that a concave defect or a void can be prevented from being formed in a plating film. Especially useful for

FIGS. 3A to 3E are cross-sectional views illustrating respective steps of a substrate plating method according to the first embodiment of the present invention. FIGS. 3A to 3C are cross-sectional views showing steps of a method for forming a Cu wiring having a dual damascene structure using the substrate plating method according to the first embodiment of the present invention. FIG. 3 is a view showing a state in which a bubble removing step of the substrate plating method according to the first embodiment of the present invention is not performed in the step shown in FIG. (A)-(e) is sectional drawing which shows each process of the board | substrate plating method which concerns on 2nd Embodiment of this invention. (A)-(e) is sectional drawing which shows each process of the board | substrate plating method which concerns on 3rd Embodiment of this invention. (A)-(e) is sectional drawing which shows each process of the board | substrate plating method which concerns on 4th Embodiment of this invention. (A) And (b) is a schematic diagram which shows the structure of the board | substrate plating apparatus which concerns on 5th Embodiment of this invention. It is an enlarged drawing of a portion which supports a substrate in a substrate holding mechanism of a substrate plating device concerning a 5th embodiment of the present invention. FIG. 13 is an enlarged view of a case where a portion supporting a substrate in a substrate holding mechanism of a substrate plating apparatus according to a fifth embodiment of the present invention has a conventional configuration. (A)-(c) is a schematic diagram which shows each process of the conventional board | substrate plating method. (A) And (b) is a figure for demonstrating the problem in the conventional board | substrate plating method. (A) And (b) is a figure for demonstrating the problem in the conventional board | substrate plating method. (A)-(c) is a figure for demonstrating the problem in the conventional board | substrate plating method.

Explanation of reference numerals

REFERENCE SIGNS LIST 101 substrate 102 interlayer insulating film 103 TaN barrier film 104 Cu seed film 105 bubble 106 plating solution 107 Cu plating film 111 pure water spray nozzle 112 pure water shower 113 pure water 114 bubbles in pure water 115 particles 116 ultrasonic pure water Injection nozzle 117 Ultrasonic vibration application pure water shower 118 Ultrasonic vibration generator 151 Substrate 152 First interlayer insulating film 153 Lower wiring 153a TaN barrier film 153b Cu film 154 Second interlayer insulating film 155 TaN barrier film 156 Cu seed film 157 Cu plating film 158 Bubbles 200 Plating solution 201 Plating solution tank 202 Pump 203 Filter 204 Plating bath 205 Anode electrode 206 Rectifier plate 207 Ultrasonic vibration generator 208 Plating solution recovery tank 20 9 Substrate 210 Substrate holding mechanism 210a Cathode electrode 210b Seal 211A Ultrasonic vibration applied cleaning liquid nozzle 211B Cleaning liquid nozzle 212 Cleaning waste liquid recovery tank

Claims (30)

A plating method for performing a plating process on the substrate by immersing the substrate in a plating solution with the surface to be plated facing downward,
Removing the air bubbles adsorbed on the substrate by rotating the substrate at a first rotation speed in the plating solution;
Performing a plating process on the substrate by rotating the substrate at a second rotation speed lower than the first rotation speed in the plating solution after the removing the bubbles. A substrate plating method, comprising: The method according to claim 1, wherein the first rotation speed is not less than 100 rpm and not more than 200 rpm. The substrate plating method according to claim 1, wherein the second rotation speed is not less than 10 rpm and not more than 60 rpm. The current density applied to the substrate in the step of removing the bubbles is smaller than the current density applied to the substrate in a step of performing a plating process on the substrate. Substrate plating method. Prior to the step of removing the air bubbles, the method further comprises a step of forming a seed layer on the substrate on the side to be plated,
The substrate plating method according to claim 1, wherein the step of removing the bubbles includes a step of preventing dissolution of the seed layer in the plating solution. The substrate plating method according to claim 1, wherein the size of the bubble is 10 µm or less. In the plating solution, the substrate is held by a substrate holding mechanism having an electrode in contact with the surface to be plated and a seal in contact with the surface to be plated so as to protect the electrode from the plating solution,
The substrate plating method according to claim 1, wherein a contact angle of the seal with the plating surface is equal to or greater than 120 ° and equal to or less than 150 °. The method according to claim 1, wherein the step of removing the air bubbles includes a step of applying ultrasonic vibration to the plating solution. Prior to the step of removing the bubbles, the method further comprises a step of performing plating treatment on the substrate in the plating solution until at least a concave portion having a minimum diameter among the concave portions provided on the surface to be plated is filled. The substrate plating method according to claim 1, wherein: 10. The substrate plating method according to claim 9, wherein a thickness of the plating film necessary for filling the concave portion having the minimum diameter is 20% or less of a target thickness of the plating film. Prior to the step of removing the bubbles, the substrate is placed in the plating solution while rotating the substrate at the first rotation speed or at a third rotation speed higher than the second rotation speed. The substrate plating method according to claim 1, further comprising a dipping step. A plating method for performing a plating process on the substrate by immersing the substrate in a plating solution with the surface to be plated facing downward,
A method for plating a substrate, comprising a step of improving the wettability of the surface to be plated before immersing the substrate in the plating solution. The substrate plating method according to claim 12, wherein the step of improving the wettability includes a step of supplying a liquid to the surface to be plated. 14. The substrate plating method according to claim 13, wherein the step of improving the wettability includes a step of removing particles attached to the surface to be plated. 15. The substrate plating method according to claim 14, wherein the step of removing the particles includes a step of applying ultrasonic vibration to the surface to be plated. The substrate plating method according to claim 14, wherein the step of removing the particles includes a step of supplying a liquid to which ultrasonic vibration is applied to the surface to be plated. After the step of improving the wettability,
By rotating the substrate at a first rotation speed in the plating solution, after removing the air bubbles adsorbed on the substrate, the substrate in the plating solution is rotated at a speed lower than the first rotation speed. 13. The method according to claim 12, further comprising: performing a plating process on the substrate by rotating the substrate at a second rotation speed. A plating bath for storing a plating solution,
A first electrode installed in the plating bath;
A substrate holding mechanism for holding a substrate to be plated;
A second electrode provided on the substrate holding mechanism and in contact with a surface to be plated of the substrate;
A seal installed on the substrate holding mechanism and in contact with the plating target surface so as to protect the second electrode from the plating solution;
A substrate plating apparatus, comprising: a liquid supply mechanism that supplies a liquid to which ultrasonic vibration is applied to the surface to be plated outside the plating bath. 19. The substrate plating apparatus according to claim 18, further comprising a plating solution circulation mechanism for circulating the plating solution stored in the plating bath. 20. The substrate plating apparatus according to claim 18, wherein the substrate holding mechanism rotates while holding the substrate. 19. The substrate plating apparatus according to claim 18, wherein the first electrode is made of a material that does not dissolve in the plating solution. 19. The apparatus according to claim 18, wherein the first electrode is made of platinum. 20. The substrate plating apparatus according to claim 18, wherein a contact angle of the seal with the plating surface is equal to or greater than 120 ° and equal to or less than 150 °. A plating bath for storing a plating solution,
A first electrode installed in the plating bath;
A substrate holding mechanism for holding a substrate to be plated;
A second electrode provided on the substrate holding mechanism and in contact with a surface to be plated of the substrate;
A seal installed on the substrate holding mechanism and in contact with the plating target surface so as to protect the second electrode from the plating solution;
A substrate plating apparatus comprising: an ultrasonic vibration applying mechanism that is installed in the plating bath and applies ultrasonic vibration to the plating solution stored in the plating bath. 25. The substrate plating apparatus according to claim 24, further comprising a liquid supply mechanism that supplies a liquid to the surface to be plated outside the plating bath. 25. The substrate plating apparatus according to claim 24, further comprising a plating solution circulation mechanism for circulating the plating solution stored in the plating bath. 25. The substrate plating apparatus according to claim 24, wherein the substrate holding mechanism rotates while holding the substrate. 25. The substrate plating apparatus according to claim 24, wherein the first electrode is made of a material that does not dissolve in the plating solution. 25. The substrate plating apparatus according to claim 24, wherein the first electrode is made of platinum. 25. The substrate plating apparatus according to claim 24, wherein the contact angle of the seal with the surface to be plated is 120 ° or more and 150 ° or less.

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