WO2013180063A1

WO2013180063A1 - Plating device, plating method, and storage medium

Info

Publication number: WO2013180063A1
Application number: PCT/JP2013/064644
Authority: WO
Inventors: 水谷　信崇; 崇田中; 岩下　光秋
Original assignee: 東京エレクトロン株式会社
Priority date: 2012-05-30
Filing date: 2013-05-27
Publication date: 2013-12-05
Also published as: TW201409573A; US20150167174A1; JP2013249495A; KR102052131B1; KR20150016275A

Abstract

A plating method is provided that makes it possible to improve the uniformity of the thickness of a plating layer that is formed on the inner surface of a concave section. The plating method comprises a step in which a substrate having a concave section formed thereon is prepared inside of a casing, and a plating step in which a plating solution is supplied to the substrate and a plating layer having a specific function is formed on the inner surface of the concave section. With regards to the plating step, after the plating solution is supplied to the substrate and the concave section of the substrate is filled with the plating solution that has been supplied thereto, plating solution having a temperature that is higher than that of the aforementioned plating solution is used on the substrate.

Description

Plating processing apparatus, plating processing method, and storage medium

The present invention relates to a plating method, a plating apparatus, and a storage medium that perform plating on a recess formed in a substrate.

Generally, wiring for forming a circuit is formed on a substrate such as a semiconductor wafer or a liquid crystal substrate for forming a semiconductor device. As a method for forming the wiring, a damascene method or the like in which a concave portion such as a via or a trench for embedding a wiring material such as copper is formed in the substrate and the wiring material is embedded in the concave portion is used.

In recent years, attempts have been made to reduce the mounting area of a component or the entire system by mounting a plurality of LSIs on a substrate using a three-dimensional mounting technique. In the three-dimensional mounting technology, for example, a recess (for example, a silicon through electrode (TSV)) in which a wiring material for connecting LSIs is embedded is formed on a substrate (for example, a silicon substrate).

In general, between the inner surface of the concave portion of the substrate and the wiring formed in the concave portion, atoms constituting the wiring material are present in the insulating film (oxide film, PI “polyimide”, etc.) on the inner surface of the concave portion and the substrate on the back side thereof. A barrier film is provided for the purpose of preventing diffusion and improving adhesion. In general, a seed film is provided between the barrier film and the wiring to facilitate embedding of the wiring material.

For example, in Patent Document 1, a barrier film containing ruthenium is formed on the inner surface of the recess by sputtering, then a seed film containing ruthenium and copper is formed on the barrier film by sputtering, and then copper is plated in the recess by plating. A method of embedding in is proposed.

JP 2010-177538 A

In recent years, the development of production technology using TSV has been underway. In this fabrication technique, the height or depth of the recesses in the TSV is several tens to several hundreds of microns rather than the tens to hundreds of nanometers in the conventional pre-process. For this reason, the conventional device creation technique may be diverted, but a different method may be required.

For example, a sputtering method generally used for forming a barrier film or a seed film is a method having a large directivity. For this reason, when the height or depth of the concave portion is large, it is difficult to sufficiently form a barrier film or a seed film up to the lower portion of the concave portion.

In order to solve such problems, it is conceivable to use a plating method such as electrolytic plating or electroless plating. By the way, when the diameter of a recessed part is small and the height or depth of a recessed part is large, the fluidity | liquidity of the plating solution in a recessed part is low. This leads to a non-uniform distribution of the plating solution concentration in the recess at the upper and lower portions of the recess. When the concentration distribution of the plating solution in the recess is non-uniform, it is considered that the thickness and density distribution of the plating layer such as the barrier film and the seed film formed on the inner surface of the recess become non-uniform.

The present invention has been made in consideration of such points, and provides a plating method, a plating apparatus, and a storage medium that can improve the uniformity of the thickness of the plating layer formed on the inner surface of the recess. The purpose is to do.

According to a first aspect of the present invention, in a plating method for performing plating on a recess formed in a substrate, a step of preparing the substrate on which the recess is formed inside a casing; A plating step for forming a plating layer having a specific function on the inner surface of the recess, and the plating step supplies a plating solution to the substrate, and the plating solution is provided in the recess of the substrate. A plating method using a plating solution having a temperature higher than that of the plating solution after the substrate is filled is provided.

According to a second aspect of the present invention, in a plating apparatus for performing plating on a recess formed in a substrate, a substrate holding mechanism that holds the substrate on which the recess is formed, and a plating solution for the substrate A plating mechanism that forms a plating layer having a specific function on the inner surface of the recess, and the plating mechanism supplies a plating solution to the substrate and fills the plating solution in the recess of the substrate. Then, a plating apparatus using a plating solution having a temperature higher than that of the plating solution is provided.

According to a third aspect of the present invention, in a storage medium storing a computer program for executing a plating method for performing plating on a recess formed in a substrate, the plating method includes the recess. A step of preparing the formed substrate, and a plating step of supplying a plating solution to the substrate and forming a plating layer having a specific function on the inner surface of the concave portion, wherein the plating step uses the plating solution as a substrate. A storage medium comprising: a method of using a plating solution having a temperature higher than that of the plating solution after the plating solution is filled in the concave portion of the substrate. The

According to the present invention, the uniformity of the thickness and density distribution of the plating layer formed on the inner surface of the recess can be improved.

FIG. 1 is a side view showing a plating apparatus according to an embodiment of the present invention. 2A and 2B are plan views of the plating apparatus shown in FIG. FIG. 3 is a diagram showing a film-forming plating solution supply mechanism that supplies a high-temperature plating solution to the film-forming unit of the plating mechanism. FIG. 4 is a diagram showing a replacement plating solution supply mechanism for supplying a low temperature plating solution to a replacement unit of the plating mechanism. FIG. 5 is a flowchart showing a plating method. FIG. 6A is a diagram illustrating a process of preparing a substrate having a recess. FIG. 6B is a diagram illustrating a process of supplying a pretreatment liquid to the recess. FIG. 6C is a diagram showing a replacement step of replacing the pretreatment liquid filled in the concave portion of the substrate with a low-temperature plating solution. FIG. 6D is a diagram showing a film forming process for supplying a high-temperature plating solution to the substrate. FIG. 6E is a diagram illustrating a state in which a plating layer is formed on the inner surface of the recess. FIG. 6F is a diagram showing a process of embedding a wiring material in the recess. FIG. 7 is a diagram illustrating a state in which the pretreatment liquid is replaced with a low-temperature plating liquid. FIG. 8 is a diagram illustrating a state in which a plurality of discharge nozzles of the film forming unit supply a plating solution to the substrate. FIG. 9 is a view showing a modification of the plating solution supply mechanism. FIG. 10 is a diagram showing a modification of the replacement unit. FIG. 11 is a diagram showing the relationship between the diffusion time and the diffusion distance when the components of the plating solution diffuse in the replacement step. 12 is a diagram illustrating an example of a plating layer formed in Example 1. FIG. 13 is a diagram illustrating an example of a plating layer formed in Comparative Example 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8. First, the overall configuration of the plating apparatus 20 will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view showing the plating apparatus 20, and FIG. 2 is a plan view showing the plating apparatus 20. In the present embodiment, an example will be described in which the plating apparatus 20 is a single-wafer type apparatus that performs the plating process on the substrate 2 one by one by discharging a plating solution to the substrate 2.

The plating processing apparatus 20 has a substrate holding mechanism 110 that holds and rotates the substrate 2 inside the casing 101, and discharges the plating solution toward the substrate 2 held by the substrate holding mechanism 110, thereby having a specific function. A plating mechanism 30 for forming a plating layer on the inner surface of the concave portion of the substrate; and a plating solution supply mechanism that is connected to the plating mechanism 30 and supplies a plating solution to the plating mechanism 30. Among these, the plating mechanism 30 directs a high-temperature plating solution having a temperature higher than the temperature of the plating solution used in the replacement unit 55 and the replacement unit 55 for discharging the low-temperature plating solution toward the substrate 2. And a film forming unit 35 for discharging. “Low temperature” means that the temperature of the plating solution discharged from the replacement unit 55 is such that the plating reaction does not proceed significantly. For example, the deposition rate of the plating layer formed by the plating solution discharged from the replacement unit 55 is 10% or less compared to the deposition rate of the plating layer 15 finally obtained during the high temperature treatment. It means that Further, “high temperature” means that the temperature of the plating solution discharged from the film forming unit 35 is a temperature at which the plating process can be completed within a realistic processing time.

The plating solution supply mechanism includes a film forming plating solution supply mechanism 71 that supplies a high temperature plating solution to the film forming unit 35 and a replacement plating solution supply mechanism 74 that supplies a low temperature plating solution to the replacement unit 55. Have.

The plating apparatus 20 further includes a pretreatment mechanism 54 that discharges a pretreatment liquid toward the substrate 2. A pretreatment liquid supply mechanism 73 that supplies a pretreatment liquid to the pretreatment mechanism 54 is connected to the pretreatment mechanism 54. The pretreatment liquid is a liquid discharged onto the substrate 2 before discharging the plating liquid onto the substrate 2. As the pretreatment liquid, for example, pure water that has been subjected to deionization treatment, so-called deionized water (DIW) is used.

The plating apparatus 20 may further include a prewetting mechanism 57 that discharges a prewetting liquid toward the substrate 2. A pre-wet liquid supply mechanism 76 that supplies a pre-wet liquid to the pre-wet mechanism 57 is connected to the pre-wet mechanism 57. The pre-wet liquid is a liquid supplied to the substrate 2 in a dry state. By using the pre-wet liquid, for example, the affinity between the substrate 2 and the processing liquid that is subsequently supplied to the substrate 2 can be increased. As the pre-wet liquid, for example, ion water containing CO ₂ ions or the like is used.

The substrate holding mechanism 110 has a first opening 121 and a second opening 126 around the substrate holding mechanism 110. The drainage cup 120 receives a liquid such as a plating solution or a pretreatment liquid scattered from the substrate 2, and an opening for drawing a gas. An exhaust cup 105 having a portion 106 is disposed. The liquid received by the first opening 121 and the second opening 126 of the drainage cup 120 is discharged by the first drainage mechanism 122 and the second drainage mechanism 127. The gas drawn into the opening 106 of the exhaust cup 105 is exhausted by the exhaust mechanism 107. Further, the drainage cup 120 is connected to the lifting mechanism 164, and the lifting mechanism 164 can move the drainage cup 120 up and down. For this reason, by raising and lowering the drainage cup 120 according to the type of liquid splashed from the substrate 2, the path through which the liquid is discharged can be made different according to the type of liquid.

(Substrate holding mechanism)
As shown in FIG. 2, the substrate holding mechanism 110 includes a hollow cylindrical rotating shaft member 111 that extends vertically in the casing 101, a turntable 112 attached to the upper end of the rotating shaft member 111, and a turntable 112. A wafer chuck 113 that supports the substrate 2 and a rotation mechanism 162 that is connected to the rotation shaft member 111 and that rotates the rotation shaft member 111.

Among these, the rotation mechanism 162 is controlled by the control mechanism 160 and rotates the rotation shaft member 111, whereby the substrate 2 supported by the wafer chuck 113 is rotated. In this case, the control mechanism 160 can rotate or stop the rotation shaft member 111 and the wafer chuck 113 by controlling the rotation mechanism 162. Further, the control mechanism 160 can control the rotational speed of the rotating shaft member 111 and the wafer chuck 113 to be increased, decreased, or maintained at a constant value.

(Plating mechanism)
Next, the film forming unit 35 and the replacement unit 55 of the plating mechanism 30 will be described. First, the film forming unit 35 will be described. The film forming unit 35 includes a discharge nozzle 34 that discharges the plating solution toward the substrate 2 and a discharge head 33 provided with the discharge nozzle 34. The discharge head 33 accommodates piping for guiding the plating solution supplied from the plating solution supply mechanism 71 to the discharge nozzle 34, piping for circulating a heat medium for keeping the plating solution warm, and the like. .

The discharge head 33 is configured to be movable in the vertical direction and the horizontal direction. For example, the ejection head 33 is attached to the distal end portion of the arm 32, and the arm 32 can be extended in the vertical direction and is fixed to the support shaft 31 that is rotationally driven by the rotation mechanism 165. By using such a rotating mechanism 165 and the support shaft 31, as shown in FIG. 2A, a discharge position at which the discharge head 33 is discharged when discharging the plating solution toward the substrate 2, and the plating solution It is possible to move between the standby positions that are located when the ink is not discharged.

As shown in FIG. 1, the ejection head 33 may extend to correspond to the length from the center of the substrate 2 to the peripheral edge of the substrate 2, that is, the radius of the substrate 2. In this case, the discharge head 33 may be provided with a plurality of discharge nozzles 34 for discharging the plating solution. In this case, the plating solution can be simultaneously supplied over a wide area of the substrate 2 by positioning the discharge head 33 so that the plurality of discharge nozzles 34 are arranged along the radial direction of the substrate 2 when discharging the plating solution. Although not shown, the discharge nozzle 34 formed in the discharge head 33 may be configured to extend along the radial direction of the substrate 2 and discharge the plating solution to the substrate 2. Also in this case, the plating solution can be supplied simultaneously over a wide area of the substrate 2.

Next, the replacement unit 55 will be described. As shown in FIG. 1, the first replacement unit 55 includes a discharge nozzle 55a that discharges a plating solution toward the substrate 2, and a discharge head 53 provided with the discharge nozzle 55a. The discharge head 53 is configured to be movable in the vertical direction and the horizontal direction. For example, as in the case of the ejection head 33 of the film forming unit 35, the ejection head 53 of the replacement unit 55 is attached to the tip of the arm 52. The arm 52 can be extended in the vertical direction and is fixed to a support shaft 51 that is rotationally driven by a rotation mechanism 166. In this case, as shown in FIG. 2B, the ejection head 53 is horizontally arranged around the support shaft 51 between a position corresponding to the central portion of the substrate 2 and a position corresponding to the peripheral portion of the substrate 2. It is movable.

(Plating solution supply mechanism)
Next, the plating solution supply mechanism 71 and the replacement plating solution supply mechanism 74 of the plating solution supply mechanism for supplying the plating solution to the film formation unit 35 and the replacement unit 55 of the plating mechanism 30 will be described with reference to FIG. I will explain. The film forming plating solution supply mechanism 71 and the replacement plating solution supply mechanism 74 differ only in whether or not a heating unit for heating the plating solution is provided, and the other configurations are the same. Here, the plating solution supply mechanism 71 for film formation will be mainly described.

3, the plating solution supply mechanism 71 has a tank 71b for storing the plating solution 71c and a supply pipe 71a for supplying the plating solution 71c in the tank 71b to the plating mechanism 30. A valve 71d and a pump 71e for adjusting the flow rate of the plating solution 71c are attached to the supply pipe 71a. The tank 71b is provided with a heating unit 71g for heating the plating solution 71c stored in the tank 71b.

(Plating solution)
Next, the plating solution used in this embodiment will be described. The plating solution supplied from the film-forming plating solution supply mechanism 71 to the film-forming unit 35 and the plating solution supplied from the replacement plating-solution supply mechanism 74 to the replacement unit 55 are substantially the same except for the temperature. is there. Hereinafter, the term “plating solution” used when describing the materials and components of the plating solution represents both the plating solution used in the film forming unit 35 and the plating solution used in the replacement unit 55.

The plating solution contains a material corresponding to a plating layer having a specific function formed on the surface of the substrate 2. For example, when the plating layer formed on the substrate 2 by the plating apparatus 20 is a barrier film that prevents the metal material constituting the wiring from penetrating into the insulating film or the inside of the substrate 2, the plating solution is a barrier film. Co (cobalt), W (tungsten), Ta (tantalum), and the like, which are materials for the above, are included. Further, when the plating layer formed on the substrate 2 by the plating apparatus 20 is a seed film for facilitating the embedding of the wiring material, the plating solution contains Cu (copper) or the like used as the wiring material. Yes. In addition, the plating solution may contain complexing agents, reducing agents (compounds containing B (boron), P (phosphorus)), surfactants, etc. Good.

Further, the plating solution may contain an additive capable of affecting the rate of the plating reaction. The additive is appropriately selected according to the material contained in the plating solution. For example, when the plating solution contains Co and W as materials for the barrier film, the plating solution contains bis (3-sulfopropyl) disulfide, so-called SPS, as an additive.

(Pretreatment mechanism and pre-wet mechanism)
Next, the pretreatment mechanism 54 and the pre-wet mechanism 57 will be described. The pretreatment mechanism 54 has a discharge nozzle 54 a that discharges the pretreatment liquid toward the substrate 2. Similarly, the pre-wet mechanism 57 has a discharge nozzle 57 a that discharges a pre-wet liquid toward the substrate 2. As shown in FIG. 1, each

discharge nozzle

54a, 57a may be attached to the above-described discharge head 53 that is movable in the vertical direction and the horizontal direction.

(Pretreatment liquid supply mechanism and pre-wet liquid supply mechanism)
Next, a pretreatment liquid supply mechanism 73 that supplies a pretreatment liquid to the pretreatment mechanism 54 and a prewet liquid supply mechanism 76 that supplies a prewet liquid to the prewet mechanism 57 will be described with reference to FIG. Note that the pretreatment liquid supply mechanism 73 and the pre-wet liquid supply mechanism 76 differ only in the types of stored treatment liquids, and the other configurations are substantially the same. Here, the pretreatment liquid supply mechanism 73 will be mainly described.

As shown in FIG. 4, the pretreatment liquid supply mechanism 73 includes a tank 73b that stores a pretreatment liquid 73c such as DIW, a supply pipe 73a that supplies the pretreatment liquid 73c in the tank 73b to the pretreatment mechanism 54, have. A valve 73d and a pump 73e for adjusting the flow rate of the pretreatment liquid 73c are attached to the supply pipe 73a.

The pretreatment liquid supply mechanism 73 may further include a deaeration unit 73f that removes gas such as dissolved oxygen and dissolved hydrogen in the pretreatment liquid 73c. As shown in FIG. 4, the deaeration unit 73 f may be configured as a gas supply pipe that sends an inert gas such as nitrogen into the pretreatment liquid 73 c stored in the tank 73 b. As a result, the inert gas can be dissolved in the pretreatment liquid 73c, whereby oxygen, hydrogen, or the like already dissolved in the pretreatment liquid 73c can be discharged to the outside. That is, a so-called degassing process can be performed on the pretreatment liquid 73c. The degree of the degassing process by the degassing means 73f is not particularly limited. For example, the degassing process is performed so that the oxygen concentration in the cleaning liquid 73c discharged toward the substrate 2 is 1 ppm or less, preferably 0.5 ppm or less. To be implemented.

The plating apparatus 20 configured as described above is driven and controlled by the control mechanism 160 in accordance with various programs recorded in the storage medium 161 provided in the control mechanism 160, whereby various processes are performed on the substrate 2. Here, the storage medium 161 stores various programs such as various setting data and a plating processing program described later. As the storage medium 161, known media such as a computer-readable memory such as ROM and RAM, and a disk-shaped storage medium such as a hard disk, CD-ROM, DVD-ROM, and flexible disk can be used.

Plating method will now be described operation and effects of the embodiment having such a configuration. Here, a plating method for forming a CoWB barrier film on the inner surface of the recess 12 formed on the substrate 2 by electroless plating will be described. FIG. 5 is a flowchart showing the plating method. 6A to 6F are cross-sectional views showing the state of the substrate 2 in each step of the plating method.

First, the recess 12 for embedding the wiring material is formed in the substrate 2. As a method of forming the concave portion 12 on the substrate 2, a conventionally known method can be appropriately employed. Specifically, for example, a general-purpose technique using fluorine-based or chlorine-based gas can be applied as the dry etching technique. In particular, in order to form a recess 12 having a large aspect ratio (ratio of hole depth to hole diameter), ICP-RIE (Inductively Coupled Plasma Reactive Ion Etching) capable of high-speed deep etching is possible. It is possible to more suitably employ a method employing the technique of ion etching. In particular, a method called a Bosch process in which an etching step using sulfur hexafluoride (SF ₆ ) and a protection step using a Teflon-based gas such as C ₄ F ₈ are repeated can be suitably employed.

The specific shape of the recess 12 is not particularly limited as long as the movement of each component of the plating solution inside the recess 12 is mainly based on diffusion rather than flow. For example, the aspect ratio of the recess 12 is in the range of 5-30. Specifically, when the cross section of the recess is circular, the diameter of the recess 12 is in the range of 0.5 to 20 μm, for example, 8 μm. The height or depth of the recess 12 is in the range of 10 to 250 μm, for example, 100 μm. Thereafter, an insulating film is formed inside the recess 12. As a method of forming the insulating film, for example, a method of forming a silicon oxide film (SiO ₂ ) deposited by a chemical vapor deposition (CVD) method is used.

Next, the substrate 2 is prepared inside the casing 101, and the prewetting mechanism 57 is used to discharge the prewetting liquid 76c toward the substrate 2 (prewetting step S10). Thereby, as shown in FIG. 6A, the surface of the substrate 2, for example, the inner surface 12a of the recess 12 and the upper surface of the substrate 2, can be brought into contact with the pre-wet liquid 76c. Thereby, the affinity between the surface of the substrate 2 and the pretreatment liquid to be supplied to the substrate 2 later can be increased. As the pre-wet liquid 76c, for example, ion water containing CO ₂ ions or the like is used.

Next, the pretreatment liquid 73c is discharged toward the substrate 2 using the pretreatment mechanism 54 (pretreatment step S20). Thereby, as shown in FIG. 6B, the inside of the recess 12 is filled with the pretreatment liquid 73c. As the pretreatment liquid 73c, for example, DIW subjected to a degassing process is used.

Next, using the plating mechanism 30, a plating solution 71c for depositing CoWB is discharged toward the substrate 2 (plating step S21). As shown in FIG. 5, the plating step S21 includes a replacement step S21a for discharging a low-temperature plating solution 74c toward the substrate 2, and a film-forming step S21b for discharging a high-temperature plating solution 71c toward the substrate 2. Contains.

In the replacement step S <b> 21 a, first, the low-temperature plating solution 74 c is supplied to the replacement unit 55 using the replacement plating solution supply mechanism 74. The temperature of the supplied plating solution 74c is a temperature at which the plating reaction does not proceed significantly, and is, for example, room temperature (about 25 ° C.). Next, the plating solution 74 c is discharged toward the substrate 2 from the discharge nozzle 55 a attached to the discharge head 53.

By the way, as described above, the recess 12 formed in the substrate 2 has a large aspect ratio. Moreover, the depth of the recessed part 12 is remarkably large compared with the depth of the conventional recessed part, for example, is 100 micrometers. When supplying the plating solution 74c to such a deep recess 12, each component contained in the plating solution 74c reaches the lower part of the recess 12 mainly based on diffusion in the plating solution. By the way, the diffusion phenomenon is a phenomenon that progresses gradually with time. For this reason, a predetermined time is required for each component of the plating solution 74c to reach the lower part of the recess 12 sufficiently. Therefore, the replacement step S21a for supplying the plating solution 74c to the substrate 2 is continued for a predetermined time so that the pretreatment solution 73c in the recess 12 can be sufficiently replaced with the plating solution 74c.

Hereinafter, an example of a method for determining the duration of the replacement step S21a will be described.

The unsteady state diffusion in the plating solution is generally expressed by Fick's second law shown below.

Here, D is the diffusion coefficient of the component to be diffused, C is the concentration of the component to be diffused, t is time, and x is the distance from the reference position. FIG. 11 shows the result of calculating the relationship between the diffusion time and the diffusion distance when the plating component (component of the material constituting the plating layer) in the plating solution diffuses based on Fick's second law. In FIG. 11, the horizontal axis represents time, and the vertical axis represents the distance from the upper end of the recess 12. In this calculation, when the time t = 0, only the pretreatment liquid 73c is filled in the recess 12, and when the time t = 0, it exists above the upper end of the recess 12. It is assumed that the solution is replaced with the plating solution 74c. Further, it is assumed that the depth of the recess 12 is infinite. In FIG. 11, the solid line or broken line annotated with “x% (x = 50, 65, 80, 88 or 95)” indicates that the concentration of the plating component at the corresponding distance is the plating component at the upper end of the recess 12. Represents the diffusion time required to reach x% of the concentration. For example, the point marked with A in FIG. 11 is the diffusion time required for the concentration of the plating component at a distance of 70 μm from the upper end of the recess 12 to reach 95% of the concentration of the plating component at the upper end of the recess 12. Means 600 seconds.

The duration of the replacement step S21a can be determined based on the relationship shown in FIG. For example, for the recess 12 having a depth of 100 μm, when the concentration of the plating component at the bottom of the recess 12 is required to reach about 90% of the concentration of the plating component of the plating solution 74c supplied to the substrate 2, The duration of the replacement step S21a is set to about 600 seconds. In this way, by continuing the replacement step S21a for a long time, the plating solution 74c can sufficiently reach the bottom of the recess 12. Thereby, the concentration distribution of the plating solution 74c filled in the recess 12 can be made substantially uniform.

In the present embodiment, as described above, the temperature of the plating solution 74c supplied to the substrate 2 in the replacement step S21a is set to a low temperature at which the plating reaction does not proceed significantly. For example, plating is performed so that the deposition rate of the plating layer formed in the replacement step S21a is 10% or less compared to the deposition rate of the thickness of the plating layer 15 finally obtained during the high temperature treatment. The temperature of the liquid 74c is set. For this reason, it is possible to prevent the plating reaction from proceeding significantly before the plating solution 74 reaches the bottom of the recess 12 sufficiently.

Thereafter, a high-temperature plating solution 71c is discharged toward the substrate 2 by using the film forming unit 35 (film forming step S21b). Specifically, first, the plating solution 71 c heated to a high temperature is supplied to the film formation unit 35 using the film formation plating solution supply mechanism 71. The temperature of the supplied plating solution 71c is set so that the plating reaction proceeds at an appropriate speed, and is set to 45 ° C., for example. Next, as shown in FIG. 8, the plating solution 71 c is discharged toward the substrate 2 from the plurality of discharge nozzles 34 arranged so as to be aligned along the radial direction of the substrate 2. Thereby, the plating solution 71c can be simultaneously supplied over a wide area of the substrate 2. Thereby, the temperature distribution of the plating solution 71 c on the substrate 2 can be made substantially uniform regardless of the position on the substrate 2. For example, the temperature of the plating solution 71c reaching the central portion of the substrate 2 and the temperature of the plating solution 71c reaching the peripheral portion of the substrate 2 can be made substantially the same.

Incidentally, when the film forming step S21b is started, as described above, the low temperature plating solution 74c is already filled in the recess 12. In this case, when the high-temperature plating solution 71 c is supplied to the substrate 2, first, the low-temperature plating solution 74 c is above the upper end of the recess 12, that is, above the upper surface 11 a of the insulating layer 11. It is replaced with 71c. Next, the low temperature plating solution 74c filled in the recess 12 is heated by the heat from the high temperature plating solution 71c. Here, in general, the heat conduction speed in the liquid is larger than the diffusion speed of the predetermined component in the liquid. For this reason, the low-temperature plating solution 74c in the recess 12 is rapidly heated to become a high-temperature plating solution 71c. That is, the hot plating solution 71c can be quickly filled in the recess 12. The plating solution 74c and the plating solution 71c are assigned the same reference numerals, but are substantially the same except for the temperature as described above. Therefore, by heating the low temperature plating solution 74c, the low temperature plating solution 74c can be replaced with or changed by the high temperature plating solution 71c.

When the inside of the recess 12 is filled with the high-temperature plating solution 71c, the plating layer 15 is formed on the inner surface 12a of the recess 12 as shown in FIG. 6E. Here, as described above, the high-temperature plating solution 71 c in the recess 12 is obtained by heating the low-temperature plating solution 74 c having a substantially uniform concentration distribution in the recess 12. For this reason, according to the present embodiment, the concentration distribution of the plating solution 71c in the recess 12 can be made uniform as compared with the case where the replacement step is not performed in advance. Thus, the plating reaction in the film forming step S21b can be started using the plating solution 71c having a substantially uniform concentration regardless of the position of the recess 12. Thereby, the uniformity of the thickness and density distribution of the plating layer 15 formed on the inner surface 12a of the recess 12 can be improved.

Thereafter, rinse treatment steps S32 and S40 for discharging a rinsing liquid toward the substrate 2, a post-cleaning step S33 for discharging a post-cleaning liquid toward the substrate 2, and a drying step S41 for drying the substrate 2 with air, IPA or the like The subsequent process is performed. In this way, the substrate 2 having a barrier film made of the plating layer 15 on the surface can be obtained.

Thereafter, as shown in FIG. 6F, a seed film 16 may be formed on the barrier film made of the plating layer 15. In addition, a wiring 17 containing a metal material such as copper may be formed in the recess 12 covered with the seed film 16. Although the method for forming the seed film 16 and the wiring 17 is not particularly limited, for example, an electroless plating method can be used. At this time, as in the case of forming the barrier film made of the plating layer 15, a two-step plating process using two types of plating solutions having different temperatures may be performed.

According to the present embodiment, as described above, the plating step S21 includes the replacement step S21a using the low temperature plating solution 74c and the film forming step 21b using the high temperature plating solution 71c. By carrying out the plating process in two stages in this way, when the plating reaction in the high-temperature plating solution 71 c is advanced, the concentration distribution of the plating solution 71 c in the recess 12 is substantially the same regardless of the position in the recess 12. It can be made uniform. Thereby, the uniformity of the thickness and density distribution of the plating layer 15 formed in the recessed part 12 can be improved.

Also, according to the present embodiment, as described above, DIW that has been subjected to degassing treatment is used as the pretreatment liquid 73c supplied to the substrate 2 in the pretreatment step S20. For this reason, it can prevent that the bubble resulting from the dissolved gas in the pretreatment liquid 73c is formed on the surface of the substrate 2 such as the inner surface 12a of the recess 12. Thereby, it is possible to prevent the plating reaction on the surface of the substrate 2 from being hindered by bubbles, and thus the plating layer 15 can be uniformly formed on the surface of the substrate 2.

Further, according to the present embodiment, as described above, ion water containing CO ₂ ions or the like is used as the pre-wet liquid supplied to the substrate 2 in the pre-wet process S10. For this reason, compared with the case where electrically neutral process liquids, such as DIW, are first supplied to the board | substrate 2, it can suppress that discharge arises in the case of a plating process.

Further, according to the present embodiment, as described above, the plating solution 71 c is discharged to the substrate 2 from the plurality of discharge nozzles 34 that are arranged along the radial direction of the substrate 2. For this reason, the temperature distribution of the plating solution 71 c on the substrate 2 can be made substantially uniform regardless of the position on the substrate 2. Thereby, the thickness of the plating layer 15 formed on the substrate 2 can be made uniform regardless of the position on the substrate 2.

In the replacement step S21a according to the present embodiment, as shown in FIG. 7, while the discharge head 53 is moving in the direction along the arrow S, from the discharge nozzle 55a attached to the discharge head 53, A low temperature plating solution 74 c may be discharged toward the substrate 2. In this case, a speed component corresponding to the moving speed of the discharge head 53 is added to the speed component of the discharged plating solution 74c. For this reason, the force by which the plating solution 74c pushes the pretreatment solution 73c along the direction S can be increased. Further, an impact force based on the kinetic energy of the plating solution 74c can be directly applied to the pretreatment solution 73c filled in each recess 12. By these things, the efficiency which replaces the pretreatment liquid 73c with the plating liquid 74c can be improved.
Note that the direction along the arrow S is parallel to the direction from the center of the substrate 2 toward the peripheral edge of the substrate 2, for example.

Further, in the present embodiment, an example in which the heating unit 71g for heating the plating solution 71c supplied to the plating mechanism 30 is provided in the tank 71b is shown. However, the form for heating the plating solution 71c is not limited to this. For example, the heating unit 71g may be provided in the supply pipe 71a instead of the tank 71b.

In the present embodiment, a tank 71b for supplying the high-temperature plating solution 71c to the film forming unit 35 and a tank 74b for supplying the low-temperature plating solution 74c to the replacement unit 55 are separately prepared. showed that. However, the invention is not limited to this, and a tank for supplying the high-temperature plating solution 71c to the film forming unit 35 and a tank for supplying the low-temperature plating solution 74c to the replacement unit 55 are shared. Also good. For example, as shown in FIG. 9, a tank 74b that stores a low-temperature plating solution 74c can be used as a common tank. In this case, as shown in FIG. 9, the supply pipe 71 a of the plating solution supply mechanism 71 for film formation is provided with a heating unit 71 g for heating the plating solution. Accordingly, the high temperature plating solution 71 c can be supplied to the film forming unit 35 and the low temperature plating solution 74 c can be supplied to the replacement unit 55 while using one tank.

In some cases, the plating solution heated by the heating unit 71g may be required to return to the tank 74b again without being supplied to the substrate 2. In this case, although not shown, a return pipe for returning the high-temperature plating solution to the tank 74b may be further provided. Further, a cooling unit for cooling the plating solution may be attached to the return pipe. Thereby, the plating solution returned to a low temperature can be returned to the tank 74b. The cooling unit attached to the return pipe and the heating unit 71g attached to the supply pipe 71a may be configured as an integral heat exchanger.

Further, in the present embodiment, an example is shown in which the discharge nozzle 34 that discharges the high-temperature plating solution 71c and the discharge nozzle 55a that discharges the low-temperature plating solution 74c are separately prepared. However, the present invention is not limited to this, and the discharge nozzle that discharges the high-temperature plating solution 71c and the discharge nozzle that discharges the low-temperature plating solution 74c may be shared.

Also, in the film forming step S21b of the present embodiment, an example in which the low temperature plating solution 74c already filled in the recess 12 is heated by supplying the high temperature plating solution 71c to the substrate 2 has been shown. However, the method for using the high-temperature plating solution for the substrate 2 is not limited to this. For example, by heating the substrate 2 or the turntable 112, the low temperature plating solution 74c filled in the recess 12 of the substrate 2 may be heated, thereby obtaining the high temperature plating solution 71c. At this time, the method for heating the substrate 2 is not particularly limited, and various methods can be used. For example, as illustrated in FIG. 10, the film forming unit 35 may further include a substrate heating unit 36 that heats the substrate 2. As the substrate heating unit, a lamp heater 36 that irradiates light toward the substrate 2 and thereby heats the substrate 2 may be used. The substrate heating unit 36 may be configured to circulate a heat medium such as warm water below the substrate 2 and thereby heat the substrate 2. When the substrate 2 is heated from below, the plating solution filled in the recess 12 is heated from the lower side of the recess 12. Heating the plating solution from the lower side of the recess 12 in this way is considered advantageous when a type of plating solution that preferentially forms a plating layer on the upper portion of the recess 12 is used. This is because, by heating the plating solution from the lower side of the recess 12, the plating reaction can be started first in the lower portion of the recess 12, and thereby the thickness of the plating layer formed in the lower portion of the recess 12 and the recess 12. This is because the difference between the thickness of the plating layer formed on the upper part of the metal layer can be reduced.

In the present embodiment, an example in which a barrier film made of the plating layer 15 is formed directly on the inner surface 12a of the recess 12 formed in the insulating layer 11 is shown. However, the present invention is not limited to this, and other layers may be interposed between the inner surface 12a of the recess 12 and the barrier film. For example, a catalyst layer for promoting the plating reaction may be interposed between the inner surface 12a of the recess 12 and the barrier film. The material which comprises a catalyst layer is suitably selected according to the material which comprises a plating layer. For example, when the plating layer is CoWB, Pd (palladium) can be used as a material constituting the catalyst layer. Further, an adhesion layer for improving the adhesion between the inner surface 12a of the recess 12 and the catalyst layer may be further provided. The adhesion layer can be formed, for example, by performing a SAM treatment using a coupling agent such as a silane coupling agent. An insulating film such as TEOS or PI (polyimide) may be formed on the inner surface 12 a of the recess 12.

Further, in the present embodiment, an example is shown in which the plating apparatus 20 is a single-wafer type apparatus that performs the plating process on the substrate 2 one by one by discharging a plating solution to the substrate 2. However, the plating apparatus to which the technical idea of the present invention can be applied is not limited to a single wafer type apparatus. For example, the plating apparatus according to the embodiment of the present invention may be a so-called dip type apparatus that can collectively perform the plating process on the plurality of substrates 2. In the dip type apparatus, the plating solution is supplied to the substrate 2 by putting the substrate 2 into the plating tank in which the plating solution is stored. Other configurations are substantially the same as those of the single-wafer plating apparatus 20 described above, and thus detailed description thereof is omitted.

In addition, although several modifications with respect to each embodiment mentioned above have been demonstrated, naturally, it is also possible to apply a combination of a plurality of modifications appropriately.

Example 1
An example in which the CoWB plating layer 15 is formed on the inner surface 12a of the recess 12 of the insulating layer 11 of the substrate 2 using the above-described plating apparatus 20 will be described.

First, a substrate 2 including an insulating layer 11 in which a recess 12 was formed was prepared. The diameter of the recess 12 was 8 μm, and the depth of the recess 12 was 100 μm.

Next, a pre-wet process S10 was performed, and then a pre-process S20 for discharging a pre-treatment liquid toward the substrate 2 was performed. Thereby, the pretreatment liquid was filled in the recess 12. As the pretreatment liquid, DIW subjected to degassing treatment was used.

Next, a plating step S21 for forming the plating layer 15 on the inner surface 12a of the recess 12 was performed. Specifically, first, a replacement step S21a for discharging a plating solution at 25 ° C. toward the substrate 2 was performed for 20 minutes. Next, a film forming step S21b for discharging a plating solution at 65 ° C. toward the substrate 2 was performed for 5 minutes. The concentration of SPS contained in each plating solution was 5 ppm. Thereafter, appropriate post-processes such as the rinse treatment process S32 were performed.

The plating layer formed by the plating step S21 was observed. Specifically, the plating layer formed in the upper part and the lower part (bottom part) of the recessed part 12 was observed. The results are shown in FIG.

(Comparative Example 1)
A CoWB plating layer was formed on the inner surface 12a of the recess 12 of the insulating layer 11 of the substrate 2 in the same manner as in Example 1 except that the replacement step S21a was not performed. That is, in Comparative Example 1, only the step of discharging a plating solution at 65 ° C. toward the substrate 2 over 5 minutes was performed as the plating step. Moreover, the formed plating layer was observed. The results are shown in FIG.

As shown in FIG. 13, in Comparative Example 1, many places where the plating layer was not formed on the inner wall 12 a of the recess 12 were confirmed. On the other hand, as shown in FIG. 12, in Example 1, the plating layer could be uniformly formed on the inner wall 12 a of the recess 12 in both the upper portion and the lower portion of the recess 12. In Example 1, each component of the plating solution can be sufficiently diffused in the concave portion 12 by performing the substitution step prior to the film forming step. As a result, the inner surface 12a of the concave portion 12 can be uniformly distributed. It can be considered that the plating layer could be formed.

2 Substrate 12 Recessed portion 15 Plating layer 20 Plating treatment device 30 Plating mechanism 101 Casing 110 Substrate holding mechanism

Claims

In the plating method for performing plating on the recesses formed on the substrate,
Preparing the substrate with the recesses formed inside the casing;
A plating step of supplying a plating solution to the substrate and forming a plating layer having a specific function on the inner surface of the recess, and
The plating process is a plating method in which a plating solution is supplied to the substrate, and after filling the plating solution in the concave portion of the substrate, a plating solution having a temperature higher than that of the plating solution is used for the substrate.
A pretreatment step of supplying a pretreatment liquid to the substrate;
In the plating step, a plating solution is supplied to the substrate, and the pretreatment liquid filled in the concave portion of the substrate is replaced with the plating solution. After the replacement step, the plating solution is supplied to the substrate. Forming a plating layer by supplying the
The plating method according to claim 1, wherein the temperature of the plating solution used in the replacement step is lower than the temperature of the plating solution used in the film formation step.
The plating process method according to claim 2, wherein the film forming step includes a step of supplying a plating solution heated to a temperature higher than a temperature of the plating solution used in the replacement step to the substrate.
3. The plating method according to claim 2, wherein the film forming step includes a step of heating the plating solution supplied to the substrate to a temperature higher than the temperature of the plating solution used in the replacement step.
The plating method according to any one of claims 2 to 4, wherein the pretreatment liquid is made of deionized water that has been degassed.
The plating method according to claim 5, further comprising a pre-wetting step that is performed before the pretreatment step and supplies ion water containing ions to the substrate.
In the film forming step, the plating solution is discharged to the substrate from a plurality of discharge nozzles arranged along the radial direction of the substrate or from a discharge nozzle extending along the radial direction of the substrate. The plating method according to any one of 2 to 6.
In a plating apparatus that performs a plating process on a recess formed in a substrate,
A substrate holding mechanism for holding the substrate on which the recess is formed;
A plating mechanism for supplying a plating solution to the substrate and forming a plating layer having a specific function on the inner surface of the recess, and
The said plating mechanism is a plating processing apparatus which supplies a plating solution with respect to a board | substrate and uses the plating solution of temperature higher than the said plating solution with respect to a board | substrate after filling the plating solution in the said recessed part.
A pretreatment mechanism for supplying a pretreatment liquid to the substrate;
The plating mechanism includes a replacement unit that supplies the substrate with a plating solution that replaces the pretreatment liquid filled in the concave portion of the substrate, and the replacement unit that supplies the plating solution to the substrate, And a film forming unit for supplying a plating solution
The plating apparatus according to claim 8, wherein the temperature of the plating solution used in the replacement unit is lower than the temperature of the plating solution used in the film forming unit.
The plating apparatus according to claim 9, wherein the film forming unit is configured to supply a plating solution heated to a temperature higher than a temperature of the plating solution used in the replacement unit to the substrate.
The plating apparatus according to claim 9, wherein the film forming unit is configured to heat the plating solution supplied to the substrate to a temperature higher than the temperature of the plating solution used in the replacement unit.
The plating apparatus according to any one of claims 9 to 11, wherein the pretreatment liquid is made of degassed deionized water.
The plating apparatus according to claim 12, further comprising a pre-wet mechanism for supplying ion water containing ions to the substrate before supplying the pretreatment liquid to the substrate.
The film forming unit is arranged along the radial direction of the substrate and includes a plurality of discharge nozzles for discharging the plating solution to the substrate, or extends along the radial direction of the substrate, and the plating solution is supplied to the substrate. The plating apparatus as described in any one of Claims 9 thru | or 13 containing the discharge nozzle which discharges.
In a storage medium storing a computer program for executing a plating method for performing plating on a recess formed in a substrate,
The plating method is:
Preparing the substrate with the recesses formed inside the casing;
A plating step of supplying a plating solution to the substrate and forming a plating layer having a specific function on the inner surface of the recess, and
The plating step comprises a method of supplying a plating solution to the substrate and filling the concave portion of the substrate with the plating solution, and then using a plating solution having a temperature higher than the plating solution on the substrate. A storage medium characterized by the above.