SUBSTRATE PROCESSING METHOD, SUBSTRATE PROCESSING APPARATUS, AND STORAGE MEDIUM

Abstract

A substrate processing method according to an embodiment of the present invention includes a preparation step, a removal step, and a metal layer formation step. In the preparation step, a substrate (W) in which a first metal layer is formed on a front face (Wa) is prepared. In the removal step, at least a portion of a first metal layer formed on a peripheral edge part (Wc) of the substrate (W) is removed. In the metal layer formation step, a second metal layer is deposited on the front surface (Wa) of the substate (W) using the first metal layer as a catalyst, after the removal step.

Description

[Technical field]

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a storage medium. [Background technology]

[0002] Conventionally, a known method for forming multilayer wiring on a semiconductor wafer substrate involves performing an electroless plating process using a copper seed layer formed inside a via as a catalyst to fill the inside of the via with copper wiring (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-102448 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for improving the uniformity of the film thickness of a plating layer formed on a substrate. [Means for solving the problem]

[0005] A substrate processing method according to an embodiment of the present disclosure includes a preparation step, a removal step, and a metal layer formation step. The preparation step prepares a substrate having a first metal layer formed on a front surface thereof. The removal step removes at least a portion of the first metal layer formed on a peripheral portion of the substrate. The metal layer formation step, after the removal step, deposits a second metal layer on the front surface of the substrate using the first metal layer as a catalyst. Effect of the Invention

[0006] According to the present disclosure, it is possible to improve the uniformity of the film thickness of a plating layer formed on a substrate. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a configuration of a substrate processing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the configuration of the plating processing unit according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing the configuration of a seed layer removal unit according to the embodiment. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing an example of a state of a peripheral edge portion of a substrate before the substrate processing according to the embodiment. [Diagram 5] FIG. 5 is a diagram for explaining the removal process according to the embodiment. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing an example of a state of a peripheral edge portion of a substrate after a removal process according to an embodiment. [Figure 7] FIG. 7 is a diagram for explaining the rinsing process according to the embodiment. [Figure 8] FIG. 8 is a diagram for explaining the drying process according to the embodiment. [Figure 9] FIG. 9 is a diagram showing the film thickness distribution of the plating layer in the example and the reference example. [Figure 10] FIG. 10 is a flowchart showing a processing procedure in the substrate processing according to the embodiment. [Figure 11] FIG. 11 is a flowchart showing a processing procedure in the plating process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, with reference to the attached drawings, embodiments of the substrate processing method, substrate processing apparatus, and storage medium disclosed in the present application will be described in detail. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, and the like may differ from reality. Furthermore, there may be parts in which the dimensional relationship and ratio differ between the drawings.

[0009] Conventionally, a known method for forming multilayer wiring on a semiconductor wafer as a substrate is to perform electroless plating using a copper seed layer formed inside a via as a catalyst, thereby filling the inside of the via with copper wiring.

[0010] On the other hand, in the conventional technology, the seed layer is formed non-uniformly on the substrate, which leads to non-uniform supply of electrons required for deposition of the plating layer, and this may adversely affect the uniformity of the thickness of the plating layer. Such a problem may occur particularly in the peripheral portion of the substrate where the seed layer is easily formed non-uniformly.

[0011] Therefore, there is a need for a technology that can overcome the above-mentioned problems and improve the uniformity of the thickness of the plating layer formed on the substrate.

[0012] <Outline of substrate processing equipment> First, a schematic configuration of a substrate processing apparatus 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of the substrate processing apparatus 1 according to an embodiment. In the following, to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined, and the positive direction of the Z-axis is defined as the vertical upward direction.

[0013] 1, the substrate processing apparatus 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0014] The loading / unloading station 2 includes a carrier mounting table 11 and a transport section 12. On the carrier mounting table 11, a plurality of carriers C are mounted, each of which horizontally accommodates a plurality of substrates, in this embodiment, semiconductor wafers (hereinafter also referred to as substrates W).

[0015] A plurality of load ports are arranged on the carrier placement table 11 adjacent to the transfer section 12, and one carrier C is placed on each of the plurality of load ports.

[0016] The transfer section 12 is provided adjacent to the carrier mounting table 11, and includes therein a substrate transfer device 13 and a transfer section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds the substrate W. The substrate transfer device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the substrate W between the carrier C and the transfer section 14 using the wafer holding mechanism.

[0017] The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15 and a plurality of plating sections 5. The plating sections 5 are an example of a metal layer forming section. The plurality of plating sections 5 are arranged side by side on both sides of the transport section 15. The configuration of the plating sections 5 will be described later.

[0018] The transfer section 15 includes a substrate transfer device 17 therein. The substrate transfer device 17 includes a wafer holding mechanism that holds the substrate W. The substrate transfer device 17 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the substrate W between the delivery section 14 and the plating processing section 5 using the wafer holding mechanism.

[0019] The substrate processing apparatus 1 also includes a control device 9. The control device 9 is, for example, a computer, and includes a control unit 91 and a storage unit 92. The storage unit 92 stores programs for controlling various processes executed in the substrate processing apparatus 1. The control unit 91 controls the operation of the substrate processing apparatus 1 by reading out and executing the programs stored in the storage unit 92.

[0020] Incidentally, such a program may be recorded in a computer-readable storage medium and installed in the storage unit 92 of the control device 9 from the storage medium.

[0021] Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnet optical disks (MO), and memory cards.

[0022] In the substrate processing apparatus 1 configured as described above, first, the substrate transport device 13 in the loading / unloading station 2 removes the substrate W from the carrier C placed on the carrier placement table 11, and places the removed substrate W on the transfer section 14.

[0023] The substrate W placed on the transfer section 14 is removed from the transfer section 14 by the substrate transport device 17 of the processing station 3, transported to the plating processing section 5, and processed by the plating processing section 5.

[0024] For example, a barrier layer M0 (see FIG. 4) and a seed layer M1 (see FIG. 4) are laminated on the surface of the substrate W, and the plating processing unit 5 performs a plating layer formation process on the surface of the seed layer M1 by electroless plating. The seed layer M1 is an example of a first metal layer, and the plating layer is an example of a second metal layer.

[0025] The substrate W processed by the plating processing section 5 is carried out from the plating processing section 5 by the substrate transport device 17 and placed on the delivery section 14. Then, the processed substrate W placed on the delivery section 14 is returned to the carrier C of the carrier mounting table 11 by the substrate transport device 13.

[0026] <Overview of Plating Department> Next, a schematic configuration of the plating processing section 5 will be described with reference to Fig. 2. Fig. 2 is a diagram showing the configuration of the plating processing section 5 according to an embodiment. The plating processing section 5 is configured, for example, as a single-wafer processing unit that processes substrates W one by one.

[0027] The plating processing section 5 is configured to perform liquid processing including electroless plating processing. The plating processing section 5 includes a chamber 51, a substrate holding section 52 arranged in the chamber 51 and horizontally holding the substrate W, and a plating solution supply section 53 that supplies a plating solution L1 to a front surface (upper surface) Wa (see FIG. 3) of the substrate W held by the substrate holding section 52.

[0028] In this embodiment, the substrate holding portion 52 has a chuck member 521 that vacuum-sucks the back surface (lower surface) Wb (see FIG. 3) of the substrate W. This chuck member 521 is of a so-called vacuum chuck type.

[0029] A rotary motor 523 (rotation drive unit) is connected to the substrate holding unit 52 via a rotary shaft 522. When the rotary motor 523 is driven, the substrate holding unit 52 rotates together with the substrate W. The rotary motor 523 is supported by a base 524 fixed to the chamber 51. Note that no heat source such as a heater is provided inside the substrate holding unit 52.

[0030] The plating solution supply unit 53 has a plating solution nozzle 531 that discharges (supplies) the plating solution L1 onto the substrate W held by the substrate holding unit 52, and a plating solution supply source 532 that supplies the plating solution L1 to the plating solution nozzle 531. Of these, the plating solution supply source 532 is configured to supply the plating solution L1, which has been heated or temperature-controlled to a predetermined temperature, to the plating solution nozzle 531 via a plating solution pipe 533.

[0031] The temperature of the plating solution L1 when it is discharged from the plating solution nozzle 531 is, for example, 55° C. or more and 75° C. or less, and more preferably 60° C. or more and 70° C. or less. The plating solution nozzle 531 is held by a nozzle arm 56 and configured to be movable.

[0032] The plating solution L1 is a plating solution for autocatalytic (reducing) electroless plating. The plating solution L1 contains, for example, metal ions and a reducing agent. The metal ions contained in the plating solution L1 include, for example, cobalt (Co) ions, nickel (Ni) ions, tungsten (W) ions, copper (Cu) ions, palladium (Pd) ions, gold (Au) ions, and ruthenium (Ru) ions.

[0033] The reducing agent contained in the plating solution L1 is hypophosphorous acid, dimethylamine borane, glyoxylic acid, etc. Examples of the plating layer formed by the plating process using the plating solution L1 include CoWB, CoB, CoWP, CoWBP, NiWB, NiB, NiWP, NiWBP, Cu, Pd, Ru, etc.

[0034] The plating layer may be formed as a single layer or may be formed as two or more layers. When the plating layer has a two-layer structure, it may have a layer configuration such as CoWB / CoB or Pd / CoB in order from the seed layer M1 (see FIG. 4).

[0035] The plating processing unit 5 further includes a cleaning liquid supply unit 54 that supplies a cleaning liquid L2 to the surface of the substrate W held by the substrate holding unit 52, and a rinsing liquid supply unit 55 that supplies a rinsing liquid L3 to the surface of the substrate W.

[0036] The cleaning liquid supply unit 54 supplies the cleaning liquid L2 to the substrate W held and rotated by the substrate holding unit 52, and performs a pre-cleaning process on the seed layer M1 formed on the substrate W. The cleaning liquid supply unit 54 has a cleaning liquid nozzle 541 that ejects the cleaning liquid L2 onto the substrate W held by the substrate holding unit 52, and a cleaning liquid supply source 542 that supplies the cleaning liquid L2 to the cleaning liquid nozzle 541.

[0037] Of these, the cleaning liquid supply source 542 is configured to supply the cleaning liquid L2, which is heated or temperature-controlled to a predetermined temperature as described below, to the cleaning liquid nozzle 541 via the cleaning liquid piping 543. The cleaning liquid nozzle 541 is held by a nozzle arm 56 and is movable together with the plating liquid nozzle 531.

[0038] The cleaning solution L2 may be a dicarboxylic acid or a tricarboxylic acid. The dicarboxylic acid may be, for example, an organic acid such as malic acid, succinic acid, malonic acid, oxalic acid, glutaric acid, adipic acid, or tartaric acid. The tricarboxylic acid may be, for example, an organic acid such as citric acid.

[0039] The rinsing liquid supply unit 55 has a rinsing liquid nozzle 551 that discharges the rinsing liquid L3 onto the substrate W held by the substrate holder 52, and a rinsing liquid supply source 552 that supplies the rinsing liquid nozzle 551 with the rinsing liquid L3.

[0040] Of these, the rinsing liquid nozzle 551 is held by a nozzle arm 56 and is movable together with the plating liquid nozzle 531 and the cleaning liquid nozzle 541. The rinsing liquid supply source 552 is configured to supply the rinsing liquid L3 to the rinsing liquid nozzle 551 through a rinsing liquid pipe 553. For example, DIW or the like can be used as the rinsing liquid L3.

[0041] A nozzle moving mechanism (not shown) is connected to the nozzle arm 56 that holds the above-mentioned plating solution nozzle 531, cleaning solution nozzle 541, and rinsing solution nozzle 551. This nozzle moving mechanism moves the nozzle arm 56 in the horizontal and vertical directions.

[0042] More specifically, the nozzle movement mechanism enables the nozzle arm 56 to move between a discharge position where the processing liquid (plating liquid L1, cleaning liquid L2 or rinsing liquid L3) is discharged onto the substrate W and a retracted position retracted from the discharge position.

[0043] Among these, the discharge position is not particularly limited as long as the processing liquid can be supplied to any position on the surface of the substrate W. For example, it is preferable to discharge the processing liquid to a position at the center of the substrate W.

[0044] The discharge position of the nozzle arm 56 may be different when supplying the plating liquid L1, when supplying the cleaning liquid L2, and when supplying the rinsing liquid L3 to the substrate W. The retracted position is a position in the chamber 51 that does not overlap with the substrate W when viewed from above and is away from the discharge position. When the nozzle arm 56 is positioned at the retracted position, interference between the moving cover body 6 and the nozzle arm 56 is avoided.

[0045] A cup 571 is provided around the substrate holder 52. This cup 571 is formed in a ring shape when viewed from above, and receives the processing liquid splashed from the substrate W when the substrate W is rotated, and guides it to the drain duct 581.

[0046] An atmosphere blocking cover 572 is provided on the outer periphery of the cup 571 to prevent the atmosphere around the substrate W from diffusing into the chamber 51. The atmosphere blocking cover 572 is formed in a cylindrical shape extending in the vertical direction and has an open upper end. A lid body 6, which will be described later, can be inserted into the atmosphere blocking cover 572 from above.

[0047] In the embodiment, the substrate W held by the substrate holding portion 52 is covered by a lid 6. The lid 6 has a ceiling portion 61 and a side wall portion 62 extending downward from the ceiling portion 61.

[0048] The ceiling portion 61 includes a first ceiling plate 611 and a second ceiling plate 612 provided on the first ceiling plate 611. A heater 63 is interposed between the first ceiling plate 611 and the second ceiling plate 612. The first ceiling plate 611 and the second ceiling plate 612 are configured to seal the heater 63 and prevent the heater 63 from coming into contact with a processing liquid such as the plating liquid L1.

[0049] More specifically, a seal ring 613 is provided on the outer periphery of the heater 63, and the heater 63 is sealed by this seal ring 613. The first ceiling plate 611 and the second ceiling plate 612 are preferably resistant to corrosion by processing liquids such as the plating liquid L1, and may be made of, for example, an aluminum alloy. To further improve corrosion resistance, the first ceiling plate 611, the second ceiling plate 612 and the side wall portion 62 may be coated with Teflon (registered trademark).

[0050] A lid body moving mechanism 7 is connected to the lid body 6 via a lid body arm 71. The lid body moving mechanism 7 moves the lid body 6 horizontally and vertically. More specifically, the lid body moving mechanism 7 has a rotation motor 72 that moves the lid body 6 horizontally, and a cylinder 73 that moves the lid body 6 vertically.

[0051] Of these, the rotation motor 72 is attached on a support plate 74 that is provided so as to be movable up and down relative to the cylinder 73. As an alternative to the cylinder 73, an actuator (not shown) including a motor and a ball screw may be used.

[0052] The swivel motor 72 of the lid body moving mechanism 7 moves the lid body 6 between an upper position located above the substrate W held by the substrate holding part 52 and a retracted position retracted from the upper position. Of these, the upper position is a position facing the substrate W held by the substrate holding part 52 with a relatively large gap therebetween, and is a position overlapping the substrate W when viewed from above.

[0053] The retracted position is a position within the chamber 51 that does not overlap with the substrate W when viewed from above. When the lid body 6 is positioned at the retracted position, the moving nozzle arm 56 is prevented from interfering with the lid body 6. The rotation axis of the swing motor 72 extends in the vertical direction, and the lid body 6 is capable of swinging in the horizontal direction between the upper position and the retracted position.

[0054] The cylinder 73 of the lid moving mechanism 7 moves the lid 6 up and down to adjust the distance between the substrate W to which the plating solution L1 has been supplied and the first ceiling plate 611 of the ceiling section 61. More specifically, the cylinder 73 positions the lid 6 at a lower position (the position indicated by the solid line in FIG. 2) and an upper position (the position indicated by the two-dot chain line in FIG. 2).

[0055] In this embodiment, when the heater 63 is driven and the lid body 6 is positioned at the above-mentioned lower position, the plating solution L1 on the substrate holder 52 or the substrate W is heated.

[0056] The ceiling 61 and side wall 62 of the lid 6 are covered by a lid cover 64. This lid cover 64 is placed on the second ceiling plate 612 of the lid 6 via supports 65. That is, a plurality of supports 65 protruding upward from the upper surface of the second ceiling plate 612 are provided on the second ceiling plate 612, and the lid cover 64 is placed on the supports 65.

[0057] The lid cover 64 is movable horizontally and vertically together with the lid 6. In order to prevent heat from escaping from within the lid 6 to the surroundings, the lid cover 64 preferably has higher thermal insulation properties than the ceiling 61 and the side wall 62. For example, the lid cover 64 is preferably made of a resin material, and it is even more preferable that the resin material has heat resistance.

[0058] Thus, in this embodiment, the lid body 6 equipped with the heater 63 and the lid body cover 64 are integrally provided, and the cover unit 10 that covers the substrate holding portion 52 or the substrate W when positioned in the lower position is formed by the lid body 6 and the lid body cover 64.

[0059] A fan filter unit 59 that supplies clean air to the periphery of the lid 6 is provided at the top of the chamber 51. The fan filter unit 59 supplies air to the inside of the chamber 51 (particularly, the inside of the atmosphere blocking cover 572), and the supplied air flows toward the exhaust pipe 81.

[0060] A downflow of the air flowing downward is formed around the lid 6, and the gas evaporated from the processing liquid such as the plating liquid L1 flows toward the exhaust pipe 81 by this downflow. In this way, the gas evaporated from the processing liquid is prevented from rising and diffusing into the chamber 51.

[0061] The gas supplied from the fan filter unit 59 described above is exhausted by the exhaust mechanism 8.

[0062] <Configuration of seed layer removal section> The plating processing unit 5 according to the embodiment further includes a seed layer removal unit 4 that removes a part of the seed layer M1 (see FIG. 4) formed on the front surface Wa of the substrate W. The configuration of this seed layer removal unit 4 will now be described with reference to FIG. 3. FIG. 3 is a diagram showing the configuration of the seed layer removal unit 4 according to the embodiment.

[0063] 3, the seed layer removal unit 4 has a first nozzle 41, a second nozzle 42, a removing liquid supply unit 43, and a rinsing liquid supply unit 44. The first nozzle 41 and the second nozzle 42 are examples of a removing liquid ejection unit.

[0064] The first nozzle 41 is disposed below the substrate W held by the chuck member 521, and ejects the processing liquid toward the back surface Wb of the substrate W. In the embodiment, the first nozzle 41 ejects the processing liquid in a direction inclined radially outwardly of the substrate W, relative to a position on the inside of the peripheral edge Wc of the substrate W.

[0065] The second nozzle 42 is disposed below the substrate W held by the chuck member 521, and ejects the processing liquid toward the back surface Wb of the substrate W. In the embodiment, the second nozzle 42 ejects the processing liquid toward the peripheral portion Wc of the substrate W in a direction inclined radially outwardly of the substrate W.

[0066] The removing liquid supply unit 43 supplies a removing liquid L4 (see FIG. 5) to the first nozzle 41 and the second nozzle 42. The removing liquid L4 is a chemical liquid capable of removing the seed layer M1 formed on the front surface Wa of the substrate W.

[0067] Examples of the removal liquid L4 that can be used include SPM (a mixture of sulfuric acid and hydrogen peroxide), a mixture of an organic acid and hydrogen peroxide, FPM (a mixture of hydrofluoric acid and hydrogen peroxide), and APM (a mixture of ammonia water and hydrogen peroxide).

[0068] The removing liquid supply unit 43 has a removing liquid supply source 43a, a valve 43b, and a flow rate regulator 43c. The removing liquid supply source 43a supplies the removing liquid L4 to the first nozzle 41 and the second nozzle 42 through the valve 43b and the flow rate regulator 43c. The flow rate regulator 43c adjusts the flow rate of the removing liquid L4 supplied to the first nozzle 41 and the second nozzle 42.

[0069] The rinsing liquid supply unit 44 supplies a rinsing liquid L3 (see FIG. 7) to the first nozzle 41. The rinsing liquid supply unit 44 includes a rinsing liquid supply source 44a, a valve 44b, and a flow rate regulator 44c.

[0070] The rinsing liquid supply source 44a supplies the rinsing liquid L3 to the first nozzle 41 through a valve 44b and a flow rate regulator 44c. The flow rate regulator 44c regulates the flow rate of the rinsing liquid L3 supplied to the first nozzle 41.

[0071] <Embodiment> Next, details of the substrate processing according to the embodiment will be described with reference to Figures 4 to 9. Figure 4 is an enlarged cross-sectional view showing an example of a state of a peripheral edge portion Wc of a substrate W before the substrate processing according to the embodiment.

[0072] 4, elements (not shown) have already been formed on the substrate W. Various processes for forming a plating layer on the substrate W in a wiring formation process (so-called BEOL (Back End of Line)) after the formation of such elements will be described below.

[0073] 4, a barrier layer M0 and a seed layer M1 are laminated on the entire front surface Wa of the substrate W, including the peripheral edge portion Wc. Then, the substrate W with the barrier layer M0 and the seed layer M1 laminated on the front surface Wa is carried into the above-mentioned plating processing unit 5, where a given electroless plating process is performed.

[0074] The barrier layer M0 has a function of suppressing the diffusion of atoms contained in the seed layer M1 and the plating layer into the substrate W made of silicon or the like. For example, Ta or TaN can be used as the barrier layer M0. Note that, although the example of FIG. 4 shows an example in which the barrier layer M0 is a single layer, the present disclosure is not limited to such an example, and the barrier layer M0 may have a multi-layer structure.

[0075] The seed layer M1 functions as a catalyst when a plating layer is deposited and formed on the surface of the substrate W. The seed layer M1 may be made of, for example, a metal such as copper, cobalt, tungsten, ruthenium, or nickel, or an alloy containing one of these elements as a main component.

[0076] The seed layer M1 is formed on the front surface Wa of the substrate W by a dry process such as a CVD (Chemical Vapor Deposition) method or a PVD (Physical Vapor Deposition) method.

[0077] As a result, since it is difficult to uniform the process conditions at the peripheral portion Wc of the substrate W compared to other portions, the thickness of the seed layer M1 becomes uneven, and for example, as shown in FIG. 4, the seed layer M1 may become so thick that it protrudes from the bevel portion of the substrate W toward the outer periphery.

[0078] 4, if a plating layer is formed on the front surface Wa by electroless plating, the plating layer may become thicker in the peripheral portion Wc because more electrons are supplied from the seed layer M1 to the peripheral portion Wc than in other portions. In other words, if a plating layer is formed on the front surface Wa by electroless plating on the substrate W in the state shown in FIG. 4, the uniformity of the plating layer thickness may be adversely affected.

[0079] Therefore, in the embodiment, before the electroless plating process, a removal process is performed to remove a part of the seed layer M1 in the plating processor 5. Fig. 5 is a view for explaining the removal process according to the embodiment.

[0080] 5, in the substrate processing method according to the embodiment, first, the control unit 91 (see FIG. 1) controls the substrate holding unit 52 to rotate the substrate W at a predetermined rotation speed. Furthermore, the control unit 91 controls the seed layer removal unit 4 to eject the removing liquid L4 from the first nozzle 41 and the second nozzle 42 onto the back surface Wb of the substrate W.

[0081] As a result, the control unit 91 uses the removing liquid L4 to remove the seed layer M1 formed on the front surface Wa side of the peripheral portion Wc of the substrate W. This removal process removes the seed layer M1 that has been unevenly attached to the bevel portion and the like of the substrate W, as shown in Fig. 6. Fig. 6 is an enlarged cross-sectional view showing an example of the state of the peripheral portion Wc of the substrate W after the removal process according to the embodiment.

[0082] That is, in the embodiment, the uniformity of the film thickness of the seed layer M1 formed on the front surface Wa of the substrate W can be improved by the removal process.

[0083] In the embodiment, the uniformity of the thickness of the plating layer formed in the electroless plating process described below can be improved by improving the uniformity of the thickness of the seed layer M1 formed on the front surface Wa of the substrate W. This is because, by improving the uniformity of the thickness of the seed layer M1, the amount of electrons supplied from the seed layer M1 can be made approximately uniform over the entire substrate W including the peripheral edge portion Wc.

[0084] That is, in the embodiment, by performing a removal process for removing a portion of the seed layer M1 prior to the electroless plating process, it is possible to improve the uniformity of the film thickness of the plating layer.

[0085] In the embodiment, the seed layer M1 formed on the front surface Wa side of the peripheral portion Wc of the substrate W may be removed by discharging the removing liquid L4 onto the back surface Wb of the substrate W. This makes it possible to prevent the seed layer M1 on the front surface Wa, which is necessary for the electroless plating process, from being removed, and to efficiently remove unnecessary seed layer M1 attached to the bevel portion of the substrate W.

[0086] Therefore, according to the embodiment, the uniformity of the film thickness of the plating layer formed on the substrate W can be further improved.

[0087] Furthermore, in the embodiment, in addition to the first nozzle 41, the second nozzle 42 may be used to eject the removal liquid L4 directly onto the peripheral portion Wc of the substrate W. This makes it possible to accurately remove the unnecessary seed layer M1 adhering to the bevel portion and the like of the substrate W. Therefore, according to the embodiment, the uniformity of the film thickness of the plating layer formed on the substrate W can be further improved.

[0088] 5 shows an example in which the removing liquid L4 is discharged onto the back surface Wb of the substrate W to remove a part of the seed layer M1, but the present disclosure is not limited to such an example. For example, the removing liquid L4 may be discharged onto the peripheral portion Wc of the substrate W from the front surface Wa side of the substrate W to remove at least a part of the seed layer M1 formed on the peripheral portion Wc.

[0089] Furthermore, a processing unit (not shown) different from the plating processing unit 5 may be used to perform a dry etching process on the peripheral portion Wc of the substrate W to remove at least a portion of the seed layer M1 formed on the peripheral portion Wc.

[0090] On the other hand, in the embodiment, by performing the removal process and the electroless plating process in the same processing unit (plating processing unit 5), it is possible to eliminate the time required to transport the substrate W between different processing units, thereby shortening the overall processing time for the substrate W.

[0091] The various processes after the removal process will be described below. In this embodiment, the removal process is followed by a rinse process for washing away the removing liquid L4. FIG. 7 is a diagram for explaining the rinse process according to this embodiment.

[0092] 7, the control unit 91 (see FIG. 1) controls the substrate holding unit 52 to rotate the substrate W at a predetermined rotation speed, and controls the seed layer removal unit 4 to eject the rinsing liquid L3 from the first nozzle 41 onto the rear surface Wb of the substrate W. As a result, the control unit 91 uses the rinsing liquid L3 to wash away the removing liquid L4 adhering to the rear surface Wb of the substrate W.

[0093] Next, the control unit 91 (see FIG. 1) controls the substrate holder 52 to rotate the substrate W at a predetermined rotation speed, as shown in FIG. 8, thereby performing a drying process on the substrate W. As a result, the rinsing liquid L3 adhering to the substrate W is removed.

[0094] In the embodiment, by performing a rinsing process and a drying process after the removal process, the removal liquid L4 can be removed from the substrate W, and therefore it is possible to prevent the necessary seed layer M1 from being removed by the removal liquid L4 remaining on the substrate W. Therefore, according to the embodiment, a good plating layer can be formed in the electroless plating process.

[0095] In addition, in the embodiment, an inert gas may be discharged onto the front surface Wa of the substrate W during the removal process, rinsing process, and drying process described above. This can prevent the seed layer M1 from being oxidized before the electroless plating process. Therefore, according to the embodiment, a good plating layer can be formed in the electroless plating process.

[0096] Next, the substrate W held by the substrate holder 52 is subjected to a cleaning process. In this case, first, the rotation motor 523 is driven to rotate the substrate W at a predetermined rotation speed. Next, the nozzle arm 56, which has been positioned at the retracted position (the position indicated by the solid line in FIG. 2), moves to a discharge position above the center of the substrate W.

[0097] Next, the cleaning liquid L2 is supplied from the cleaning liquid nozzle 541 to the rotating substrate W to clean the front surface Wa of the substrate W. As a result, any deposits or the like attached to the substrate W are removed from the substrate W. The cleaning liquid L2 supplied to the substrate W is discharged to the drain duct 581.

[0098] Next, the cleaned substrate W is rinsed. In this case, the rinsing liquid L3 is supplied from the rinsing liquid nozzle 551 to the rotating substrate W, and the front surface Wa of the substrate W is rinsed. This washes away the cleaning liquid L2 remaining on the substrate W. The rinsing liquid L3 supplied to the substrate W is discharged to the drain duct 581.

[0099] Next, plating solution L1 is supplied and piled on the rinsed substrate W. In this case, first, the rotation speed of the substrate W is reduced to be lower than the rotation speed during the rinsing process. For example, the rotation speed of the substrate W may be set to 50 to 150 rpm. This allows the plating layer formed on the substrate W to be uniform. Note that the rotation of the substrate W may be stopped.

[0100] Next, the plating liquid L1 is discharged from the plating liquid nozzle 531 onto the surface of the substrate W. The discharged plating liquid L1 remains on the surface of the substrate W due to surface tension, and the plating liquid L1 is piled up on the front surface Wa of the substrate W, forming a layer of the plating liquid L1 (so-called a puddle).

[0101] A part of the plating solution L1 flows out from the surface of the substrate W and is discharged from the drain duct 581. After a predetermined amount of the plating solution L1 is discharged from the plating solution nozzle 531, the discharge of the plating solution L1 is stopped. Thereafter, the nozzle arm 56, which was positioned at the discharge position, is positioned at the retracted position.

[0102] Next, the plating solution L1 piled on the substrate W is heated. First, the substrate W is covered with the lid 6. In this case, the rotation motor 72 of the lid moving mechanism 7 is driven to rotate the lid 6 in the horizontal direction and position it at the upper position (the position indicated by the two-dot chain line in FIG. 2).

[0103] Next, the cylinder 73 of the lid moving mechanism 7 is driven, and the lid 6 located at the upper position is lowered to the processing position. As a result, the distance between the plating solution L1 on the substrate W and the first ceiling plate 611 of the lid 6 becomes a given distance, and the side wall 62 of the lid 6 is positioned on the outer periphery of the substrate W.

[0104] In this embodiment, the lower end of the side wall portion 62 of the lid 6 is positioned lower than the lower surface of the substrate W. In this manner, the substrate W is covered by the lid 6, and the space around the substrate W is closed.

[0105] Next, a heating process is performed. Specifically, the heater 63 is turned on to heat the plating solution L1 piled on the substrate W. The set temperature of the heater 63 is fixed at a constant target temperature throughout the heating process, for example. When the temperature of the plating solution L1 rises to a temperature at which the components precipitate, the components of the plating solution L1 precipitate on the surface of the seed layer M1, forming a plating layer.

[0106] Next, a lid retraction process is performed. In the lid retraction process, the lid moving mechanism 7 is driven to position the lid 6 at the retracted position. In this case, first, the cylinder 73 of the lid moving mechanism 7 is driven to raise the lid 6 to the upper position. Then, the swivel motor 72 of the lid moving mechanism 7 is driven to swivel the lid 6 positioned at the upper position in the horizontal direction to position it at the retracted position.

[0107] Next, the substrate W is subjected to a rinsing process. In this case, the rotation speed of the substrate W is first increased to be higher than the rotation speed during the plating process. For example, the substrate W is rotated at the same rotation speed as that used for the rinsing process on the front surface Wa before the plating process.

[0108] Next, the rinsing liquid nozzle 551, which has been positioned at the retreated position, moves to the discharge position. Next, the rinsing liquid L3 is supplied from the rinsing liquid nozzle 551 to the rotating substrate W, thereby cleaning the surface of the substrate W. As a result, the plating liquid L1 remaining on the substrate W is washed away.

[0109] Next, the rinsed substrate W is subjected to a drying process. In this case, for example, the rotation speed of the substrate W is increased to be higher than the rotation speed of the immediately preceding rinse process, and the substrate W is rotated at a high speed. As a result, the rinsing liquid L3 remaining on the substrate W is shaken off, and the substrate W is dried.

[0110] When the drying process is completed, the substrate W is removed from the plating processing section 5 by the substrate transport device 17 and transported to the delivery section 14. The substrate W transported to the delivery section 14 is then removed from the delivery section 14 by the substrate transport device 13 and stored in the carrier C. This completes a series of substrate processing steps for one substrate W.

[0111] Fig. 9 is a diagram showing the film thickness distribution of the plating layer in the example and the reference example. In the reference example shown in Fig. 9, the plating layer is formed under the same conditions as the example, except that the above-mentioned removal treatment is not performed.

[0112] 9 shows the film thickness distribution when the measurement point is gradually moved from the inner circumference to the outer circumference, with measurement point 25 corresponding to a position 1.5 (mm) inward from the edge of substrate W, and measurement point 49 corresponding to the position of the edge of substrate W. Furthermore, in the graph of FIG. 9, measurement point 37 corresponds to the position of the notch of substrate W.

[0113] As shown in FIG. 9, in the embodiment and the reference example, the film thickness of the plating layer from the inner circumference to the peripheral edge portion Wc hardly varies, showing good uniformity.

[0114] However, in the reference example, it can be seen that the plating layer thickness at the peripheral portion Wc is largely varied in the direction of increasing in thickness compared to the inner peripheral portion. Note that the variation in the plating layer thickness over the entire substrate W in the reference example was about 2.6(%).

[0115] On the other hand, in the example in which the seed layer M1 was removed prior to the electroless plating process, the uniformity of the plating layer thickness at the peripheral portion Wc was improved compared to the reference example, as shown in Fig. 9. The variation in the plating layer thickness across the entire substrate W in the example was approximately 1.8(%).

[0116] In the embodiments described above, the plating layer is formed by electroless plating, but the present disclosure is not limited to such an example, and the plating layer may be formed by electrolytic plating. Even when the plating layer is formed by electrolytic plating, if the thickness of the seed layer M1 varies, the supply of electrons from the outside varies, which may adversely affect the uniformity of the thickness of the plating layer, as in the above embodiment.

[0117] Therefore, by performing a removal process to remove a portion of the seed layer M1 in the peripheral portion Wc before the electrolytic plating process, the uniformity of the film thickness of the plating layer formed on the substrate W can be improved.

[0118] The substrate processing apparatus 1 according to the embodiment includes a substrate holding unit 52, a removing solution discharge unit (first nozzle 41, second nozzle 42), a metal layer forming unit (plating unit 5), and a control unit 91. The substrate holding unit 52 holds the substrate W rotatably. The removing solution discharge unit (first nozzle 41, second nozzle 42) discharges a removing solution L4 capable of removing a first metal layer (seed layer M1) onto the back surface Wb of the substrate W. The metal layer forming unit (plating unit 5) forms a second metal layer (plating layer) on the front surface Wa of the substrate W. The control unit 91 controls each unit. The control unit 91 holds the substrate W having the first metal layer (seed layer M1) formed on the front surface Wa by the substrate holding unit 52. The control unit 91 uses the removing solution discharge unit (first nozzle 41, second nozzle 42) to remove at least a part of the first metal layer (seed layer M1) formed on the peripheral portion Wc of the substrate W. Furthermore, the control unit 91 causes the metal layer forming unit (plating processing unit 5) to deposit a second metal layer (plating layer) on the front surface Wa of the substrate W using the first metal layer (seed layer M1) as a catalyst. This makes it possible to improve the uniformity of the film thickness of the plating layer formed on the substrate W.

[0119] <Substrate processing details> Next, the substrate processing performed by the substrate processing apparatus 1 according to the embodiment will be described in detail with reference to Figures 10 and 11. Figure 10 is a flowchart showing the procedure of the substrate processing according to the embodiment.

[0120] First, the control unit 91 controls the substrate transport devices 13, 17 to transport the substrate W from the carrier C to the inside of the plating processing unit 5, and prepares the substrate W by holding the substrate W with the substrate holding unit 52 (step S101).

[0121] Next, the control unit 91 performs a removal process on the substrate W (step S102). In this case, first, the rotation motor 523 is driven to rotate the substrate W at a predetermined rotation speed. Next, the removal liquid L4 is discharged from the first nozzle 41 and the second nozzle 42 onto the rotating substrate W, and is supplied to the back surface Wb of the substrate W.

[0122] This removes at least a portion of the seed layer M1 formed on the peripheral portion Wc of the substrate W. The removing liquid L4 supplied to the substrate W is discharged to the drain duct 581.

[0123] Next, the control unit 91 performs a rinsing process on the substrate W (step S103). In this case, first, the rotation motor 523 is driven to rotate the substrate W at a predetermined rotation speed. Next, the rinsing liquid L3 is discharged from the first nozzle 41 onto the rotating substrate W and supplied to the back surface Wb of the substrate W.

[0124] This washes away the removing liquid L4 adhering to the back surface Wb of the substrate W. The rinsing liquid L3 supplied to the substrate W is discharged to the drain duct 581.

[0125] Next, the control unit 91 performs a drying process on the substrate W (step S104). In this case, for example, the control unit 91 increases the rotation speed of the substrate W to be higher than the rotation speed of the rinsing process (step S103) to rotate the substrate W at a high speed. As a result, the rinsing liquid L3 remaining on the surface of the substrate W is shaken off, and the substrate W is dried.

[0126] Next, the control unit 91 performs a plating process on the substrate W (step S105). For example, a plating layer is formed on the front surface Wa of the substrate W by precipitating the plating layer using the seed layer M1 formed on the front surface Wa of the substrate W as a catalyst. Details of the plating process will be described later.

[0127] When the plating process is completed, the substrate W is removed from the plating processing section 5 by the substrate transport device 17 and transported to the delivery section 14. The substrate W transported to the delivery section 14 is then removed from the delivery section 14 by the substrate transport device 13 and stored in the carrier C. This completes a series of substrate processing steps for one substrate W.

[0128] 11 is a flowchart showing a processing procedure in a plating process according to an embodiment. First, the control unit 91 performs a cleaning process on the substrate W (step S201). In this case, the rotation motor 523 is driven to rotate the substrate W at a predetermined rotation speed. Next, the nozzle arm 57, which has been positioned at the retreated position, moves to a discharge position above the center of the substrate W.

[0129] Next, the cleaning liquid L2 is supplied from the cleaning liquid nozzle 541 to the rotating substrate W to clean the surface of the substrate W. As a result, any deposits or the like attached to the substrate W are removed from the substrate W. The cleaning liquid L2 supplied to the substrate W is discharged to the drain duct 581.

[0130] Next, the control unit 91 performs a rinsing process on the substrate W (step S202). In this case, the rinsing liquid L3 is supplied from the rinsing liquid nozzle 551 to the rotating substrate W, and the surface of the substrate W is rinsed. This washes away the cleaning liquid L2 remaining on the substrate W. The rinsing liquid L3 supplied to the substrate W is discharged to the drain duct 581.

[0131] Next, the control unit 91 supplies the plating liquid L1 onto the substrate W, thereby piling the plating liquid L1 on the substrate W (step S203). That is, the control unit 91 forms a puddle of the plating liquid L1 on the substrate W.

[0132] Next, the control unit 91 covers the substrate W with the lid 6 (step S204). As a result, the space around the substrate W is closed by the lid 6.

[0133] Next, the control unit 91 heats the puddle of the plating solution L1 formed on the substrate W (step S205). Specifically, the control unit 91 operates the heater 63 to heat the plating solution L1 puddled on the substrate W.

[0134] Then, the control unit 91 performs a lid retraction process to retract the lid 6 from the vicinity of the substrate W (step S206). Specifically, the control unit 91 operates the lid moving mechanism 7 to move the lid 6 from the vicinity of the substrate W to a given retracted position.

[0135] Next, the control unit 91 performs a rinsing process on the substrate W (step S207). In this case, first, the cover 6 is retracted from above the substrate W. Next, the rotation motor 523 is driven to rotate the substrate W at a predetermined rotation speed.

[0136] Then, the rinsing liquid L3 is supplied from the rinsing liquid nozzle 551 to the rotating substrate W, thereby rinsing the surface of the substrate W. This washes away the plating liquid L1 remaining on the substrate W. The rinsing liquid L3 supplied to the substrate W is discharged to the drain duct 581.

[0137] Next, the rinsed substrate W is dried (step S208). In this case, for example, the rotation speed of the substrate W is increased to be higher than the rotation speed of the rinse process (step S107) to rotate the substrate W at a high speed. As a result, the rinsing liquid L3 remaining on the substrate W is shaken off and the substrate W is dried. This completes a series of plating processes for one substrate W.

[0138] The substrate processing method according to the embodiment includes a preparation step (step S101), a removal step (step S102), and a metal layer formation step (step S105). The preparation step (step S101) prepares a substrate W having a first metal layer (seed layer M1) formed on its front surface Wa. The removal step (step S102) removes at least a part of the first metal layer (seed layer M1) formed on the peripheral portion Wc of the substrate W. The metal layer formation step (step S105), after the removal step (step S102), deposits a second metal layer (plating layer) on the front surface Wa of the substrate W using the first metal layer (seed layer M1) as a catalyst. This can improve the uniformity of the film thickness of the plating layer formed on the substrate W.

[0139] Moreover, in the substrate processing method according to the embodiment, the removal step (step S102) is performed by discharging a removal solution L4 capable of removing the first metal layer (seed layer M1) onto the back surface Wb of the substrate W. This can further improve the uniformity of the film thickness of the plating layer formed on the substrate W.

[0140] In the substrate processing method according to the embodiment, the remover L4 is an aqueous solution containing at least one selected from sulfuric acid, hydrofluoric acid, an organic acid, and ammonia, and hydrogen peroxide, thereby making it possible to efficiently remove the seed layer M1 unevenly attached to the bevel portion of the substrate W.

[0141] Moreover, the substrate processing method according to the embodiment further includes a rinsing step (step S103) and a drying step (step S104). In the rinsing step (step S103), after the removing step (step S102), a rinsing liquid L3 is discharged onto the back surface Wb of the substrate W to clean the substrate W. In the drying step (step S104), after the rinsing step (step S103), the substrate W is dried. This allows a good plating layer to be formed in the plating process.

[0142] In the substrate processing method according to the embodiment, an inert gas is discharged onto the front surface Wa of the substrate W during the removing step (step S102), the rinsing step (step S103), and the drying step (step S104). This allows a good plating layer to be formed in the plating process.

[0143] In the substrate processing method according to the embodiment, the first metal layer (seed layer M1) is mainly composed of one element selected from copper, cobalt, tungsten, ruthenium, and nickel, which allows various plating layers to be formed by electroless plating.

[0144] In the substrate processing method according to the embodiment, the second metal layer (plating layer) is mainly composed of one element selected from copper, cobalt, ruthenium, and nickel, which allows wiring and the like to be efficiently formed on the substrate W by using various plating layers.

[0145] In the substrate processing method according to the embodiment, the removing step (step S102) and the metal layer forming step (step S105) are performed in the same processing unit, thereby making it possible to reduce the overall processing time for the substrate W.

[0146] In the substrate processing method according to the embodiment, the removing step (step S102) and the metal layer forming step (step S105) are performed in different processing units. This can improve the uniformity of the film thickness of the plating layer formed on the substrate W.

[0147] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0148] The disclosed embodiments should be considered to be illustrative and not restrictive in all respects. Indeed, the above-described embodiments may be embodied in various forms. In addition, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0149] 1. Substrate processing equipment (example of plating processing equipment) 4. Seed layer removal section 5. Plating section (an example of a metal layer forming section) 41 First nozzle (an example of a removal liquid ejection portion) 42 Second nozzle (an example of a removal liquid ejection part) 52 Board holding part 91 Control Unit L3 Rinse solution L4 Removal Solution M1 seed layer (an example of the first metal layer) W substrate Wa Front Wb back side Wc Periphery

Claims

1. a preparation step of preparing a substrate having a first metal layer formed on a front surface thereof; a removing step of discharging a removing liquid capable of removing the first metal layer onto a rear surface of the substrate to remove at least a portion of the first metal layer formed on a peripheral portion of the substrate; a rinsing step of discharging a rinsing liquid onto a rear surface of the substrate to clean the substrate after the removing step; a drying step of drying the substrate after the rinsing step; a metal layer forming step of depositing a second metal layer on the front surface of the substrate using the first metal layer as a catalyst after the drying step; Including, The removing step includes discharging the removing liquid from a first nozzle that discharges liquid on the rear surface of the substrate toward the inner side of the peripheral portion and a second nozzle that discharges liquid on the rear surface of the substrate toward the peripheral portion, The rinsing step includes discharging the rinsing liquid from the first nozzle. A method for processing a substrate.

2. The remover is an aqueous solution containing hydrogen peroxide and at least one selected from the group consisting of sulfuric acid, hydrofluoric acid, an organic acid, and ammonia. The method for processing a substrate according to claim 1 .

3. An inert gas is discharged onto the front surface side of the substrate during the removing step, the rinsing step, and the drying step. The substrate processing method according to claim 1 .

4. The first metal layer is mainly composed of one element selected from the group consisting of copper, cobalt, tungsten, ruthenium, and nickel. The substrate processing method according to claim 1 .

5. The second metal layer is mainly composed of one element selected from the group consisting of copper, cobalt, ruthenium, and nickel. The substrate processing method according to claim 1 .

6. The removing step and the metal layer forming step are performed in the same processing unit among a plurality of processing units provided in one substrate processing system. The substrate processing method according to claim 1 .

7. The removing step and the metal layer forming step are performed in different processing units among a plurality of processing units provided in one substrate processing system. The substrate processing method according to claim 1 .

8. a substrate holder that rotatably holds the substrate; a first nozzle that ejects liquid onto a rear surface of the substrate inward from a peripheral edge of the substrate; a second nozzle that ejects liquid onto the peripheral portion of the rear surface of the substrate; a metal layer forming section for forming a second metal layer on the front surface of the substrate; A control unit for controlling each unit; Equipped with The control unit is The substrate having a first metal layer formed on a front surface thereof is held by the substrate holding portion; a removing liquid capable of removing the first metal layer is discharged from the first nozzle and the second nozzle to remove at least a portion of the first metal layer formed on the peripheral portion of the substrate; A rinse liquid is discharged from the first nozzle to clean the substrate; Rotating the substrate holder to dry the substrate; Using the metal layer forming unit, a second metal layer is deposited on the front surface of the substrate using the first metal layer as a catalyst. Substrate processing equipment.

9. A computer-readable storage medium storing a program for operating on a computer and controlling a substrate processing apparatus, The program, when executed, causes a computer to control the substrate processing apparatus so as to perform the substrate processing method according to claim 1 or 2. storage medium.

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