JP2007254882A - Electroplating device and electroplating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a plating film of high film quality to a substrate having an electrically conductive layer (seed layer) with a resistivity equal to or above that of copper at a more uniform film thickness over the whole face. <P>SOLUTION: The electroplating device comprises: a sealing material 90 abutted against the peripheral part of the surface in a substrate held by a substrate holding part and sealing the peripheral part; a cathode contact 88 contacted with an electrically conductive layer formed on the surface of the substrate held by the substrate holding part, and energizing the same; and a housing 94 where an anode 98 to be dipped into a plating liquid is stored at the inside, and a porous structural body 110 is arranged at the edge part of an opening opposite to the substrate held by the substrate holding part, so as to dividedly form a plating liquid chamber 100. The plating liquid chamber 100 is divided into a plurality of chambers 154a, 154b with a partition plate 150, the anode 98 is composed of divided anodes 98a, 98b, and the respective divided anodes 98a, 98b are arranged in such a manner that independent plating current is made to flow through the inside of each chamber 154a, 154b in the plating liquid chamber 100. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrolytic plating apparatus and an electrolytic plating method used to form a buried wiring by embedding a metal such as copper in a fine wiring pattern formed on the surface (surface to be plated) of a substrate such as a semiconductor wafer. About.

  In recent years, as a metal material for forming a wiring circuit on a semiconductor substrate, instead of aluminum or an aluminum alloy, a movement of using copper having low electrical resistivity and high electromigration resistance has become prominent. This type of copper wiring is generally formed by embedding copper in a wiring recess provided on the surface of the substrate. As a method of forming this copper wiring, there are methods such as CVD, sputtering, and plating. In any case, copper is formed on almost the entire surface of the substrate, and unnecessary copper is formed by chemical mechanical polishing (CMP). To be removed.

FIG. 22 shows a manufacturing example of this type of copper wiring board W in the order of steps. First, as shown in FIG. 22A, an insulating film (interlayer insulating film) 2 made of SiO ₂ or Low-K material is deposited on a conductive layer 1a on a semiconductor substrate 1 on which a semiconductor element is formed, Inside the insulating film 2, a contact hole 3 and a trench 4 are formed as wiring recesses by lithography and etching techniques. Then, a barrier layer 5 made of TaN or the like is formed thereon, and a seed layer 7 is formed thereon as a power feeding layer for electrolytic plating.

  Then, as shown in FIG. 22B, copper is plated on the surface of the substrate W to fill the contact hole 3 and the trench 4 with copper, and to deposit a copper film 6 on the insulating film 2. Thereafter, the copper film 6, the seed layer 7 and the barrier layer 5 on the insulating film 2 are removed by chemical mechanical polishing (CMP), and the surface of the copper film 6 filled in the contact hole 3 and the trench 4 The surface of the insulating film 2 is substantially flush with the surface. Thereby, as shown in FIG. 22C, a wiring made of the copper film 6 is formed inside the insulating film 2.

  In order to perform electrolytic plating on the surface of the substrate, as shown in FIG. 23, the cathode contact 200 is brought into contact with the outer peripheral portion of the conductive layer such as the seed layer 7 formed on the surface of the substrate W, and the substrate W and the substrate W are contacted. The plating solution 204 is filled between the anode 202 and the anode 202 arranged at the opposite position. Then, a plating film is formed on the conductive layer of the substrate W by applying a plating current from the power source 206 between the cathode contact 200 and the anode 202.

Semiconductor wafers and liquid crystal substrates for LSIs tend to have a large area year by year, and there have been problems associated therewith. In other words, in the case of a large-area substrate W, the electrical resistance (sheet resistance) of the conductive layer such as the seed layer 7 from the cathode contact 200 near the outer periphery of the substrate W to the center of the substrate W increases, and in the plane of the substrate W An electric potential difference arises and a difference arises in the plating speed of each part. FIG. 23 shows an equivalent circuit of a typical electrolytic plating, and the following resistance components exist in the circuit.
R1: Power line resistance and various contact resistances between the power source 206 and the anode 202 R2: Polarization resistance at the anode 202 R3: Resistance of the plating solution 204 R4: Polarization resistance at the cathode contact 200 R5: Resistance of the conductive layer (sheet resistance)
R6: power line resistance and various contact resistances between the cathode contact 200 and the power source 206

  As is clear from FIG. 23, when the resistance R5 of the conductive layer becomes larger than the other electric resistances R1 to R4 and R6, the potential difference generated at both ends of the resistance R5 increases, and accordingly, the difference in the plating current occurs. Arise. For this reason, the growth rate of the plating film decreases at a position far from the cathode contact 200. When the conductive layer is thin, the resistance R5 is further increased, and this phenomenon appears remarkably. This phenomenon is called a terminal effect, which means that the current density is different in the plane of the substrate W, and the characteristics of the plating film itself (the resistivity, purity, embedding characteristics, etc. of the plating film) are uniform in the plane. Don't be.

  As a method for avoiding the above problems, it is conceivable to increase the thickness of the conductive layer or increase the electrical conductivity of the conductive layer. However, the substrate is not only subject to various restrictions in the manufacturing process other than plating. For example, when a thick conductive layer is formed on a fine pattern by a sputtering method, voids are likely to be generated inside the pattern. For this reason, it is not possible to easily increase the thickness of the conductive layer or change the film type of the conductive layer.

  In order to prevent this drawback, the inventor places a high-resistance structure 208 having an electric conductivity smaller than the electric conductivity of the plating solution 204 between the anode 202 and the substrate W as shown in FIG. Proposed. With this configuration, an equivalent circuit as shown in FIG. 24 is obtained, and a resistance Rp by the high-resistance structure 208 is added compared to the equivalent circuit shown in FIG. For this reason, when the resistance Rp due to the high resistance structure 208 becomes a large value, (R2 + R3 + Rp + R4) / (R2 + R3 + Rp + R4 + R5) approaches 1 and is less affected by the resistance R5, that is, the resistance component (sheet resistance) of the conductive layer.

The applicant has proposed to use a divided anode divided into arbitrary shapes as the anode (see Patent Document 1). In addition, when the substrate is placed in the tank, a voltage such that the average cathode current density with respect to the substrate surface (conductive layer) is 1 to 30 mA / cm ² may be applied between the substrate surface (conductive layer) and the anode. Proposed (see Patent Document 2).
JP 2005-213610 A JP 2004-210808 A

  However, with the further miniaturization of semiconductor devices in recent years, the thickness of conductive layers such as seed layers formed on the surface of substrates such as semiconductor wafers has become increasingly thinner, and the electrical properties of the conductive layers have also increased. Resistance (sheet resistance) is also increasing. For this reason, even if a divided anode is used as the anode, it has become difficult to form a plating film having a uniform film thickness over the entire surface of the substrate. In particular, in the current generation of the 65 nm node, even if a plating film having a sufficient thickness in-plane uniformity can be formed, as the next generation of the 45 nm node and further to the next generation of the 32 nm node, the substrate is advanced. It is considered that it is difficult to form a plating film having sufficient in-plane uniformity with a large variation in the film thickness of the plating film formed on the surface.

  Furthermore, if the seed layer is made of, for example, ruthenium in order to cope with the thinning of the seed layer, the resistance of the substrate itself is further increased. Further, due to the high resistance of the seed layer, there is a problem that a good film quality cannot be obtained with a current recipe that has been conventionally used.

  The present invention has been made in view of the above circumstances, and has a more uniform film thickness and good film quality over the entire surface of a substrate having a conductive layer (seed layer) having a resistivity equal to or higher than that of copper. It is an object of the present invention to provide an electrolytic plating apparatus and an electrolytic plating method capable of forming an appropriate plating film.

  According to the first aspect of the present invention, there is provided a substrate holding portion that holds a substrate, a sealing material that contacts a peripheral portion of the substrate surface held by the substrate holding portion and seals the peripheral portion, and is held by the substrate holding portion. A cathode contact for contacting and energizing a conductive layer formed on the surface of the substrate and an anode immersed in a plating solution are housed therein, and a porous structure is provided at an opening end facing the substrate held by the substrate holding portion. And the plating solution chamber is partitioned by a partition plate and the porous structure, and the anode is composed of a plurality of divided anodes, Each of the divided anodes is an electroplating apparatus characterized in that an independent plating current can flow inside each of the plating solution chambers.

  Thus, for example, the current density of the divided anode located on the center side is increased from the periphery only for a certain period of time when the initial plating film is formed on the substrate, and the plating current is prevented from concentrating on the outer periphery of the substrate. The plating current also flows to the center side of the substrate, which reduces the in-plane difference in current density due to the sheet resistance on the substrate surface, even for substrates with higher sheet resistance, and more uniform film thickness The plating film can be reliably formed. Since this is effective for the terminal effect, a plating film having a more uniform film thickness can be obtained. In addition, the electric fields of the divided anodes can be prevented from interfering with each other, and the effect of using the divided anodes can be prevented from diminishing.

The invention according to claim 2 is characterized in that a seal ring is interposed between the porous structure and the partition plate and / or between the partition plate and the housing. Electrolytic plating apparatus.
Thereby, between the porous structure and the partition plate and / or between the partition plate and the housing is sealed with the seal ring, it is possible to reliably prevent current from leaking through the plating solution.

According to a third aspect of the present invention, the anode is composed of a split anode divided concentrically, the split anode located in the center is in a disc shape, and the partition plate is formed in a cylindrical shape, The electroplating apparatus according to claim 1, wherein the electroplating apparatus is disposed so as to surround a periphery of the divided anode located at the center.
As a result, the electric field is prevented from being dispersed, and a specialized current can be passed through the central portion of the substrate facing the disc-shaped divided anode located at the center, thereby reducing the sheet resistance of the conductive layer. Plating can be easily applied to the central portion of the substrate while reducing the influence. The anode may be either a dissolved anode or an insoluble anode.

According to a fourth aspect of the present invention, the diameter of the disk-shaped divided anode and the inner diameter of the partition plate arranged so as to surround the disk-shaped divided anode are 2 / diameter of the substrate diameter. The electroplating apparatus according to claim 3, wherein the electroplating apparatus is 3 or less.
For example, when a plating film is formed on the surface of a wafer having a diameter of 300 mm, the diameter of the disk-shaped divided anode located in the center and the inner diameter of the partition plate surrounding the disk-shaped divided anode are Is preferably 200 mm or less and preferably 60 mm or more.

The distance between each of the divided anodes and the porous structure is preferably set within 10 mm.
By making each divided anode as close as possible to the porous structure, it becomes easy to pass a specialized current to the central portion of the substrate.

The invention according to claim 5 is characterized in that the conductive layer has at least one of Cu, Ru, Ta, TaN, W, WNC, WC, Pt, ITO, Ti, and TiW. 4. The electroplating apparatus according to any one of 4 above.
Such a conductive layer has a resistivity equal to or higher than that of copper, and it is usually difficult to perform plating more uniform than copper.

According to a sixth aspect of the present invention, a plating solution is provided between a conductive layer of a substrate in contact with a cathode contact and a divided anode arranged concentrically at a position facing the conductive layer of the substrate. Fill and place a porous structure in the plating solution, and at the initial stage of plating, a higher current between the cathode contact and the split anode located in the center than between the cathode contact and the other split anode. An electrolytic plating method is characterized in that a current having a density flows.
Thereby, more effective plating can be performed on the terminal effect, and a plating film having a more uniform film thickness can be formed.
The plating initial, current flowing between the divided anode positioned in the cathode contact and the central portion has an average cathode current density in the 40 mA / cm ² or more to the conductive layer of the substrate, it is preferable that 60 mA / cm ² or less .

The initial stage of plating is, for example, within 5000 msec after the start of plating, and preferably from 0 to 3000 msec after the start of plating.
By providing a wide initial plating time, it is possible to obtain excellent embedding properties with respect to various fine electric circuit patterns. Within 5000 msec after the start of plating, a current having an average cathode current density of 40 mA / cm ² or more with respect to the conductive layer of the substrate may be allowed to flow a plurality of times. The substrate can be applied to the plating solution by either hot entry or cold entry.

  The invention according to claim 7 is characterized in that, after the initial stage of plating, a current lower than that in the initial stage of plating is passed between the cathode contact and the divided anode located in the central portion. It is a plating method.

  In the initial stage of plating, a current having a high current density is passed between the cathode contact and the split anode located in the center, and then a second current lower than (normal) the first current is allowed to flow. A plating film with a uniform film thickness can be formed over the entire surface of the substrate, and a plating film of fine crystal particles can be formed from the contact point to the center of the substrate at a distance to form a plating film having a glossy and good quality. A film can be formed over the entire surface. Thereafter, there is no problem even if a current higher than the initial current density is passed.

  The invention according to claim 8 is the electrolytic plating method according to claim 6 or 7, wherein no current flows between the cathode contact and the other divided anode in the initial stage of the plating.

According to the present invention, the anode is composed of a plurality of divided anodes, and a plated film having better in-plane uniformity is obtained by flowing different currents to each divided anode while being insulated from each other. A film can be formed. In addition, by making the current density at the initial stage of film formation as high as 40 mA / cm ² or more, for example, plating having a glossy and good film quality on a substrate having a conductive layer having a resistivity equal to or higher than that of copper is performed. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this example, as shown in FIG. 22, a seed layer having a resistivity equal to or higher than that of copper, for example, any one of Cu, Ru, Ta, TaN, W, WNC, WC, Pt, ITO, Ti, and TiW. An example in which electrolytic copper plating is applied to the surface of a substrate such as a semiconductor wafer having (conductive layer) 7 and copper is embedded in a fine wiring recess provided on the substrate surface to form a wiring made of copper. Show.

  FIG. 1 shows an overall layout of a substrate processing apparatus including an electrolytic plating apparatus according to an embodiment of the present invention. As shown in FIG. 1, this substrate processing apparatus includes two load / unload units 10 that are located in the same facility and house a plurality of substrates W therein, and an electrolytic plating process and an incidental process thereof. Two electroplating apparatuses 12 to be performed, a transfer robot 14 for delivering the substrate W between the load / unload unit 10 and the electroplating apparatus 12, and a plating solution supply facility 18 having a plating solution tank 16 are provided. ing.

  As shown in FIG. 2, the electrolytic plating apparatus 12 includes a substrate processing unit 20 that performs a plating process and an incidental process, and a plating solution tray 22 that stores a plating solution is disposed adjacent to the substrate processing unit 20. Has been. Further, an electrode arm section 30 having an electrode head 28 that is held at the tip of a swing arm 26 that swings about the rotation shaft 24 and moves between the substrate processing section 20 and the plating solution tray 22 is provided. . Further, a pre-coat / recovery arm 32 and a fixed nozzle 34 for injecting a chemical solution such as pure water or ionic water, gas, or the like toward the substrate are disposed on the side of the substrate processing unit 20. In this embodiment, three fixed nozzles 34 are provided, and one of them is used for supplying pure water.

  As shown in FIG. 3, the substrate processing unit 20 includes a substrate holding unit 36 that holds the substrate W with the surface (surface to be plated) facing upward, and a peripheral edge of the substrate holding unit 36 above the substrate holding unit 36. A cathode portion 38 is provided so as to surround the portion. Further, a bottomed substantially cylindrical scattering prevention cup 40 that surrounds the periphery of the substrate holding part 36 and prevents the scattering of various chemicals used during processing is arranged to be movable up and down via an air cylinder (not shown). Has been.

  Here, the substrate holding unit 36 is moved up and down between a lower substrate delivery position A, an upper plating position B, and an intermediate pretreatment / cleaning position C by an air cylinder 44, and a rotary motor (not shown). And it is comprised so that it may rotate integrally with the cathode part 38 with arbitrary acceleration and speed | velocity | rate via a belt. Opposite to the substrate delivery position A, a substrate carry-in / out port (not shown) is provided on the side of the transfer robot 14 on the side of the frame of the electroplating apparatus 12, and when the substrate holding part 36 is raised to the plating position B. The sealing material 90 and cathode contact 88 of the cathode part 38 described below abut on the peripheral edge of the substrate W held by the substrate holding part 36. The upper end of the anti-scattering cup 40 is located below the substrate carry-in / out port, and as shown by the phantom line in FIG.

The plating solution tray 22 is used to wet the following porous structure 110 and the anode 98 of the electrode arm portion 30 with a plating solution when the plating process is not being performed, and can accommodate the porous structure 110. It is set to a size and has a plating solution supply port and a plating solution drain port (not shown). In addition, a photo sensor is attached to the plating solution tray 22 so that the plating solution in the plating solution tray 22 is fully filled, that is, overflow and drainage can be detected.
The electrode arm unit 30 moves up and down via a vertical movement motor and a ball screw, which are not shown, and the electrode head 28 moves between the plating solution tray 22 and the substrate processing unit 20 through a turning motor. Swivel (oscillate).

  As shown in FIG. 4, the precoat / recovery arm 32 is connected to the upper end of a support shaft 58 extending in the vertical direction, pivots (swings) via a rotary actuator 60, and passes through an air cylinder (not shown). Are configured to move up and down. The precoat / collection arm 32 holds a precoat nozzle 64 for discharging a precoat liquid on the free end side, and a plating solution recovery nozzle 66 for collecting a plating liquid on the base end side. The precoat nozzle 64 is connected to a syringe driven by an air cylinder, for example, and the precoat liquid is intermittently discharged from the precoat nozzle 64. The plating solution recovery nozzle 66 is connected to, for example, a cylinder pump or an aspirator, and the plating solution on the substrate is sucked from the plating solution recovery nozzle 66.

  As shown in FIGS. 5 to 7, the substrate holding unit 36 includes a disk-shaped substrate stage 68, and the substrate W is horizontally placed on the upper surface at six locations along the circumferential direction of the peripheral portion of the substrate stage 68. A support arm 70 is erected to be placed and held on the head. A positioning plate 72 is fixed to one upper end of the support arm 70 to be positioned in contact with the end surface of the substrate W, and a substrate is fixed to the upper end of the support arm 70 facing the support arm 70 to which the positioning plate 72 is fixed. A pressing piece 74 is pivotally supported so as to be rotated in contact with the end face of W and press the substrate W against the positioning plate 72 side. In addition, chuck claws 76 that pivot and press the substrate W downward from above are rotatably supported at the upper ends of the other four support arms 70.

  Here, the lower end of the pressing piece 74 and the chuck claw 76 is connected to the upper end of the pressing bar 80 biased downward via the coil spring 78, and the pressing piece 74 and the chuck are moved along with the downward movement of the pressing bar 80. A claw 76 is pivoted inwardly and closed, and a support plate 82 is disposed below the substrate stage 68 so as to abut the lower surface of the pressing rod 80 and push it upward.

  Thereby, when the substrate holding portion 36 is positioned at the substrate delivery position A shown in FIG. 3, the pressing rod 80 contacts the support plate 82 and is pushed upward, so that the pressing piece 74 and the chuck pawl 76 rotate outward. When the substrate stage 68 is raised by moving, the pressing rod 80 is lowered by the elastic force of the coil spring 78, and the pressing piece 74 and the chuck pawl 76 are rotated inward and closed.

  As shown in FIGS. 8 and 9, the cathode portion 38 includes an annular frame 86 fixed to the upper end of a column 84 erected on the peripheral edge of a support plate 82 (see FIG. 7 and the like), and the frame 86. In this example, the cathode contact 88 is divided into six parts and attached to the lower surface, and an annular seal member 90 is attached to the upper surface of the frame 86 so as to cover the upper side of the cathode contact 88. ing. The seal member 90 is configured such that an inner peripheral edge thereof is inclined downward inward and gradually becomes thin, and an inner peripheral end portion hangs downward.

As a result, as shown in FIG. 3, when the substrate holding part 36 rises to the plating position B, the cathode contact 88 is pressed against the peripheral edge of the substrate W held by the substrate holding part 36 and energized, and at the same time, the sealing material The inner peripheral end of 90 is in pressure contact with the upper surface of the peripheral edge of the substrate W, and this is sealed in a watertight manner, so that the plating solution supplied to the upper surface (surface to be plated) of the substrate W oozes out from the end of the substrate W. And preventing the plating solution from contaminating the cathode contact 88.
In this embodiment, the cathode portion 38 cannot move up and down and rotates integrally with the substrate holding portion 36. However, the cathode portion 38 is movable up and down, and the seal material 90 is plated on the substrate W when lowered. You may comprise so that it may press-contact to a surface.

  As shown in FIGS. 10 and 11, the electrode head 28 of the electrode arm portion 30 closes the housing 94 connected to the free end of the swing arm 26 via a ball bearing 92 and the lower end opening of the housing 94. The porous structure 110 is arranged as described above. That is, the housing 94 is formed in a bottomed cup shape that opens downward, and a concave portion 94a is formed on the inner peripheral surface of the lower portion, and a flange that fits the concave portion 94a is formed on the upper portion of the porous structure 110. Each portion 110a is provided, and the porous structure 110 is held in the housing 94 by fitting the flange portion 110a into the concave portion 94a. As a result, a hollow plating solution chamber 100 is defined in the housing 94.

  The plating solution chamber 100 is divided into two concentric chambers 152a and 152b by a partition plate 150 made of a cylindrical insulating material. A seal such as rubber or Teflon (registered trademark) is provided between the upper end surface of the partition plate 150 and the lower surface of the ceiling wall of the housing 94 and between the lower end surface of the partition plate 150 and the upper surface of the porous structure 110. Rings 154a and 154b are interposed. As a result, even if each of the rooms 152a and 152b is filled with a plating solution, current is prevented from flowing from one room 152a to the other room 152b via this plating solution, and each of the rooms 152a and 152b is electrically connected. Are insulated from each other.

The porous structure 110 has a pressure loss (when nitrogen gas is aerated at a linear velocity of 0.01 m / sec with respect to a porous structure having a thickness of 14 mm at room temperature) of 500 kPa or more, preferably 1000 kPa or more. Preferably, it is 1500 kPa or more, or the apparent porosity (according to JIS R 2205) is 19% or less, preferably 15% or less, more preferably 10% or less, and the resistivity is 1.0 × 10 ⁵ Ω · cm or more. Silicon carbide, silicon carbide whose surface is oxidized, alumina, plastic such as a sintered body of polypropylene or polyethylene, or a combination thereof. The thickness of the porous structure 110 is generally about 1 to 20 mm, preferably about 5 to 20 mm, and more preferably about 8 to 15 mm.

In this example, the porous structure 110 is made of silicon carbide (SiC) having a pressure loss of 1500 kPa, an apparent porosity of 10%, and a resistivity of 1.0 × 10 ⁶ Ω · cm. ing. Then, by containing a plating solution in the porous structure 110, that is, the porous structure 110 itself is an insulator, the plating solution is complicatedly introduced into the porous structure 110 and is considerably long in the thickness direction. By making the path follow, the electric conductivity is smaller than the electric conductivity of the plating solution.

Thus, the pressure loss is 500 kPa or more, preferably 1000 kPa or more, more preferably 1500 kPa or more, or the apparent porosity is 19% or less, preferably 15% or less, more preferably 10% or less, and the resistivity is 1. A porous structure 110 made of silicon carbide or the like having a size of 0 × 10 ⁵ Ω · cm or more is disposed in the plating solution chamber 100, and a large resistance is generated by the porous structure 110. Even if the substrate is formed with a thin seed layer 7 (see FIG. 22) having a large electric resistance, the influence of the resistance of the seed layer 7 is negligible, and the surface of the substrate W has a current density due to the electric resistance. The in-plane uniformity of the plating film can be improved by reducing the internal difference.

  In the plating solution chamber 100, an anode 98 having a large number of through-holes 98c penetrating vertically is disposed above the porous structure 110. The anode 98 is composed of two divided anodes, a central disk-shaped anode 98a and a peripheral ring-shaped anode 98b, which are concentrically divided. The disc-shaped anode (divided anode) 98 a is disposed in a room 152 a located in the center of the plating solution chamber 100, and the ring-shaped anode (divided anode) 98 b is a room located around the plating solution chamber 100. It is arranged in 152b.

  In this example, the plating solution chamber 100 is concentrically divided into two chambers 152a and 152b, and the divided anodes 98a and 98b divided into two concentrically are arranged in the respective chambers 152a and 152b. However, the plating solution chamber 100 may be concentrically divided into three or more chambers, and divided anodes that are concentrically divided into three or more may be arranged in each chamber. Further, the plating solution chamber 100 may be divided into rooms of arbitrary shapes, and divided anodes divided into arbitrary shapes may be arranged in the respective rooms.

  Here, the diameter of the disk-like anode 98a and the inner diameter of the partition plate 150 are each 2/3 or less of the diameter of the substrate W and 1/5 or more, for example, a plating film is formed on the surface of a wafer having a diameter of 300 mm. In such a case, it is preferable that the thickness is 200 mm or less and 60 mm or more. As a result, the electric field is prevented from being dispersed, and a current specialized in the central portion of the substrate facing the disc-shaped anode 98a located in the center can be passed, so that the conductive layer (seed layer 7) While the influence of the sheet resistance is eased, the central portion of the substrate can be easily plated.

  Accordingly, in this example, the surface of the seal ring 154b attached to the lower end of the partition plate 150 and the porous structure 110 is 2/3 or less of the diameter of the substrate W and 1/5 or more, for example, a wafer having a diameter of 300 mm. In the case of forming a plating film on the surface of this, they are in contact with each other along a circle of 200 mm or less and 60 mm or more. Of course, the inner diameter of the partition plate 150 and the outer diameter of the disc-shaped anode 98a do not necessarily have to coincide with each other.

  The distance between each divided anode 98a, 98b and the porous structure 110 is preferably within 10 mm. In this manner, by bringing the divided anodes 98a and 98b as close as possible to the porous structure 110, it becomes easy to pass a specialized current, for example, in the central portion of the substrate.

  The housing 94 is provided with plating solution discharge ports 103a and 103b for sucking and discharging the plating solution inside the chambers 152a and 152b of the plating solution chamber 100. The plating solution discharge ports 103a and 103b are provided with plating. It is connected to a plating solution discharge pipe 106 extending from the solution supply equipment 18 (see FIG. 1). Further, a plating solution injection part 104 is provided inside the peripheral wall of the housing 94 and is located on the side of the anode 98 and the porous structure 110 and penetrates vertically. In this example, the plating solution injection part 104 is configured by a tube having a nozzle shape at the lower end, and is connected to a plating solution supply pipe 102 extending from the plating solution supply facility 18 (see FIG. 1).

  In the plating solution injection part 104, when the substrate holding part 36 is at the plating position B (see FIG. 3), the gap between the substrate W held by the substrate holding part 36 and the porous structure 110 is, for example, 0.5 to 3 mm. The electrode head 28 is lowered to a certain level, and in this state, a plating solution is injected into the region between the substrate W and the porous structure 110 from the side of the anode 98 and the porous structure 110. Thus, the lower end nozzle portion opens in a region sandwiched between the sealing material 90 and the porous structure 110. In addition, a rubber shield ring 112 that electrically shields the outer periphery of the porous structure 110 is attached.

  At the time of injecting the plating solution, the plating solution injected from the plating solution injection unit 104 flows in one direction along the surface of the substrate W, and the flow of the plating solution causes a gap between the substrate W and the porous structure 110. The air in the region is pushed outward and discharged to the outside, and this region is filled with the fresh and adjusted plating solution injected from the plating solution injection unit 104 and partitioned by the substrate W and the sealing material 90. Accumulated in the area.

  As described above, by injecting a plating solution into the region between the substrate W and the porous structure 110 from the side of the anode 98 and the porous structure 110, an insulator is provided inside the porous structure 110. Thus, the plating solution can be filled without the need to disturb the electric field distribution, such as an electrolyte supply tube made of the above. Thereby, even in the case of a large-area substrate, the electric field distribution over the entire surface of the substrate is made more uniform, and when the plating solution is injected, the plating solution held by the porous structure 110 is porous. It is possible to prevent leakage from the body 110 and supply a fresh and adjusted plating solution in a region where the substrate W held by the substrate holding part 36 and the porous structure 110 face each other.

Here, in the electroplating apparatus 12, a reaction occurs during liquid filling, and the influence of this reaction makes it impossible for example to embed a plating film, or the characteristics of the plating film partially change. In order to prevent this, it is desirable to inject the plating solution at a linear velocity of 0.1 to 10 m / sec. It is preferable to use a plating solution injection portion 104 having an arbitrary shape that satisfies such requirements.
Here, in order to suppress the production of slime, the anode 98 is composed of copper containing 0.03 to 0.05% phosphorus (phosphorus-containing copper), but an insoluble insoluble anode is used. You may make it do.

  In this example, the disc-shaped anode (divided anode) 98a is electrically connected to the anode of the first plating power source 114a, and the cathode contact 88 is electrically connected to the cathode of the first plating power source 114a. 98b is electrically connected to the anode of the second plating power source 114b, and the cathode contact 88 is electrically connected to the cathode of the second plating power source 114b. As a result, the current flowing between the disc-shaped anode 98a and the cathode contact 88, that is, the center of the seed layer (conductive layer) 7 (see FIG. 22) formed on the surface of the substrate W, the ring-shaped anode 98b and the cathode The current flowing between the contacts 88, that is, the peripheral portion of the seed layer (conductive layer) 7 (see FIG. 22) formed on the surface of the substrate W can be individually adjusted.

  A common plating power source is used to individually adjust the current flowing between the disc-shaped anode 98a and the cathode contact 88 and the current flowing between the ring-shaped anode 98b and the cathode contact 88. May be.

  Then, when the substrate holding portion 36 is at the plating position B (see FIG. 3), the electrode is used until the gap between the substrate W held by the substrate holding portion 36 and the porous structure 110 becomes, for example, about 0.5 to 3 mm. The head 28 is lowered. In this state, the plating solution is injected into the region between the substrate W and the porous structure 110 from the plating solution injection unit 104 and filled with the plating solution, and this plating solution is stored in the region partitioned by the substrate W and the sealing material 90. Plating.

Next, the operation of the substrate processing apparatus provided with the electrolytic plating apparatus 12 of this embodiment will be described.
First, the substrate W before plating processing is taken out from the loading / unloading unit 10 by the transfer robot 14, and one surface is electroplated from the substrate loading / unloading port provided on the side surface of the frame with the surface (surface to be plated) facing upward. It is conveyed inside the device 12. At this time, the substrate holding unit 36 is at the lower substrate delivery position A, and the transport robot 14 lowers the hand after the hand reaches just above the substrate stage 68, thereby supporting the substrate W on the support arm 70. Place on top. Then, the hand of the transfer robot 14 is retreated through the substrate carry-in / out entrance.

  After the removal of the hand of the transfer robot 14 is completed, the anti-scattering cup 40 is raised, and at the same time, the substrate holding part 36 that was in the substrate delivery position A is raised to the pretreatment / cleaning position C. At this time, with this rise, the substrate placed on the support arm 70 is positioned by the positioning plate 72 and the pressing piece 74 and is securely gripped by the chuck claws 76.

  On the other hand, the electrode head 28 of the electrode arm unit 30 is at a normal position on the plating solution tray 22 at this point, and the porous structure 110 or the anode 98 is located in the plating solution tray 22. Simultaneously with the rising of the anti-scattering cup 40, supply of the plating solution to the plating solution tray 22 and the electrode head 28 is started. Then, until the substrate plating process is started, a new plating solution is supplied, and at the same time, the plating solution is sucked through the plating solution discharge pipe 106 to replace the plating solution contained in the porous structure 110 and remove bubbles. Do. When the raising of the scattering prevention cup 40 is completed, the substrate carry-in / out entrance on the side of the frame is closed and closed by the scattering prevention cup 40, and the atmosphere inside and outside the frame is cut off.

  When the anti-scattering cup 40 rises, the precoat process is started. That is, the substrate holding part 36 that has received the substrate W is rotated, and the precoat / collection arm 32 that has been in the retracted position is moved to a position facing the substrate. When the rotational speed of the substrate holding unit 36 reaches a set value, a precoat liquid made of, for example, a surfactant is applied to the surface of the substrate (surface to be plated) from a precoat nozzle 64 provided at the tip of the precoat / collection arm 32. Discharge intermittently. At this time, since the substrate holding part 36 is rotating, the precoat liquid spreads over the entire surface of the substrate W. Next, the precoat / collection arm 32 is returned to the retracted position, the rotational speed of the substrate holding part 36 is increased, and the precoat liquid on the surface to be plated of the substrate W is shaken off and dried by centrifugal force.

  After pre-coating is completed, the process proceeds to plating. First, the substrate holding unit 36 is raised to the plating position B where plating is performed in a state where the rotation is stopped or the rotation speed is reduced to the plating speed. Then, the peripheral portion of the substrate W comes into contact with the cathode contact 88 and can be energized. At the same time, the sealing material 90 is pressed against the upper surface of the peripheral portion of the substrate W, and the peripheral portion of the substrate W is sealed watertight. .

  On the other hand, based on the signal that the precoat process of the loaded substrate W has been completed, the electrode arm unit 30 is swung horizontally from above the plating solution tray 22 so that the electrode head 28 is positioned above the position where the plating process is performed. After that, the electrode head 28 is lowered toward the cathode portion 38. At this time, the porous structure 110 is brought into a position close to about 0.5 mm to 3 mm without contacting the surface of the substrate W. Then, the plating solution is injected from the plating solution injection unit 104 into the region between the substrate W and the porous structure 110 to fill the region with the plating solution.

In this state, as shown in FIG. 13, at the initial stage of plating (t _{1 to} t ₂ ), the conductivity of the central portion of the substrate is between the cathode contact 88 and the disc-shaped anode 98 a located at the central portion. A _first current is supplied from the plating power source 114a so that the average cathode electrode density with respect to the layer (seed layer 7) is A1, and the substrate is interposed between the cathode contact 88 and the ring-shaped anode 98b located on the outer periphery. the average cathode density for conductive layer of the outer peripheral portion (a seed layer 7) of such that the a _2, flows a first current from the plating power source 114b. At this time, the average cathode density at the central portion of the substrate is more of A ₁ is the average cathode density at the substrate peripheral portion is higher than _{A 2 (A 1> A 2} ) so as to.

  This prevents the plating current from concentrating on the outer periphery of the substrate and allows the plating current to flow also to the central portion side of the substrate, thereby enabling the sheet on the surface of the substrate even for a substrate having a higher sheet resistance. By reducing the in-plane difference in current density due to resistance, a plating film having a more uniform film thickness can be reliably formed. In addition, a partition plate 150 is disposed between the divided anodes 98 a and 98 b, between the upper end surface of the partition plate 150 and the lower surface of the ceiling wall of the housing 94, and the lower end surface of the partition plate 150 and the upper surface of the porous structure 110. By interposing seal rings 154a and 154b such as rubber or Teflon (registered trademark) between them, the electric fields of the divided anodes 98a and 98b are prevented from interfering with each other through the plating solution. As a result, it is possible to prevent the effect of using the divided anodes 98a and 98b from fading.

In the middle stage of plating (t _{2 to} t ₃ ), an average cathode for the conductive layer (seed layer 7) in the central portion of the substrate between the cathode contact 88 and the disc-shaped anode 98a located in the central portion. A _second current is passed from the plating power source 114a so that the electrode density becomes A ₃ (= A ₂ ), and the outer periphery of the substrate is between the cathode contact 88 and the ring-shaped anode 98b located on the outer periphery. A _second current is passed from the plating power supply 114b such that the average cathode electrode density for the conductive layer (seed layer 7) continues to be A2. As a result, a plating film is formed on the entire surface of the substrate at a substantially uniform plating rate.

In the late stage of plating (t _{3 to} t ₄ ), between the cathode contact 88 and the disc-shaped anode 98a located at the center, and between the cathode contact 88 and the ring-shaped anode 98b located at the outer periphery. A _third current higher than the second current is supplied from the plating power sources 114a and 114b so that the average cathode electrode density with respect to the conductive layer (seed layer 7) of the substrate is both A ₄ (> A ₂ = A ₃ ). . Thereby, a plating film is formed on the entire surface of the substrate at a substantially uniform higher plating rate.

  As a result, as shown in FIG. 14, a plating film having a uniform film thickness is formed on the surface of the substrate at the initial stage of plating, and the plating film is kept at a uniform plating speed from the middle stage to the latter stage while the film thickness is uniform. By growing it, a plating film having a uniform surface and a target film thickness can be obtained.

Here, the plating initial _(t 1 ~t _2), the average cathode density _{A 1} to the conductive layer of the central portion of the substrate (seed layer 7), 40 mA / cm ² or more at 60 mA / cm ² or less (60> A ₁ > 40 (mA / cm ² )), a high first current is allowed to flow between the cathode contact 88 and the disc-shaped anode 98a located in the center, and during the middle plating period (t _{2 to} t ₃ ). The first cathode electrode density A ₃ with respect to the conductive layer (seed layer 7) in the center of the substrate is 40 mA / cm ² or less, for example, 10 mA / cm ² (A ₃ = 10 mA / cm ² ). It is preferable to pass a second current lower than the current.

As a result, a plated film of fine crystal particles can be formed from the cathode contact 88 to the center of the substrate at a distance, and a plated film having a glossy and good quality can be formed over the entire surface of the substrate. In the later plating period (t _{3 to} t ₄ ) thereafter, there is no problem even if a current higher than the current density at the initial stage of plating is passed.

The initial plating period (t _{1 to} t ₂ ) is, for example, within 5000 msec after the start of plating, and preferably from 0 to 3000 msec after the start of plating. Thus, by providing a range in the initial plating time, excellent embedding properties can be obtained for various fine electric circuit patterns. Within the plating after the start 5000 msec, preferably, after the start of the plating and before lapse 0～3000Msec, a plurality of 60 mA / cm ² or less of the current at an average cathode current density to the conductive layer of the substrate is 40 mA / cm ² or more You may make it flow around.

  In this example, a plating solution is injected into a region between the substrate W and the porous structure 110 to fill the region with the plating solution, and then a voltage is applied between the cathode contact 88 and the anode 98 to perform plating. The so-called cold entry is used, but a plating solution is injected into the region between the substrate W and the porous structure 110 while applying a voltage between the cathode contact 88 and the anode 98. You may employ | adopt what is called hot entry which starts metal plating. Further, at the initial stage of plating, no current may flow between the cathode contact 88 and the ring-shaped anode (divided anode) 98b located in the peripheral portion.

  When the plating process is completed, the electrode arm part 30 is raised and turned to return to the upper part of the plating solution tray 22 and lowered to the normal position. Next, the precoat / recovery arm 32 is moved from the retracted position to a position facing the substrate W and lowered, and the plating solution remaining solution on the substrate W is recovered from the plating solution recovery nozzle 66. After the collection of the residual liquid is completed, the precoat / collection arm 32 is returned to the retracted position, and pure water is discharged from the fixed nozzle 34 for pure water to the central portion of the substrate W in order to rinse the substrate plating surface. At the same time, the substrate holder 36 is rotated at an increased speed to replace the plating solution on the surface of the substrate W with pure water. Thus, by rinsing the substrate W, when the substrate holding part 36 is lowered from the plating position B, the plating solution is prevented from splashing and the cathode contact 88 of the cathode part 38 is prevented from being contaminated.

  After rinsing, the water washing process is started. That is, the substrate holding part 36 is lowered from the plating position B to the pretreatment / cleaning position C, and the substrate holding part 36 and the cathode part 38 are rotated while supplying pure water from the fixed nozzle 34 for pure water, and water washing is performed. To do. At this time, the sealing material 90 and the cathode contact 88 can also be cleaned simultaneously with the substrate W by pure water directly supplied to the cathode portion 38 or pure water scattered from the surface of the substrate W.

  After the water washing is completed, the drying process is started. That is, the supply of pure water from the fixed nozzle 34 is stopped, the rotation speed of the substrate holding part 36 and the cathode part 38 is increased, and the pure water on the substrate surface is shaken off by the centrifugal force and dried. At the same time, the sealing material 90 and the cathode contact 88 are also dried. When the drying process is completed, the rotation of the substrate holding part 36 and the cathode part 38 is stopped, and the substrate holding part 36 is lowered to the substrate delivery position A. Then, the grip of the substrate W by the chuck claws 76 is released, and the substrate W is placed on the upper surface of the support arm 70. At the same time, the splash prevention cup 40 is also lowered.

  Thus, the plating process and all the pre-processing and cleaning / drying processes incidental thereto are completed, and the transfer robot 14 inserts the hand into the lower part of the substrate W from the substrate loading / unloading port and lifts the substrate as it is, thereby holding the substrate. The processed substrate W is received from the unit 36. Then, the transfer robot 14 returns the processed substrate W received from the substrate holding unit 36 to the load / unload unit 10.

In the above example, the porous structure 110 is made of silicon carbide having a pressure loss of 1500 kPa, an apparent porosity of 10%, and a resistivity of 1.0 × 10 ⁶ Ω · cm. For example, the pressure loss is 500 kPa or more, preferably 1000 kPa or more, more preferably 1500 kPa or more, or the apparent porosity is 19% or less, preferably 15% or less, more preferably 10% or less. However, it is preferable to use any one such as silicon carbide adjusted to 1.0 × 10 ⁵ Ω · cm or more, or any one adjusted at least one of bulk specific gravity and water absorption, Plating may be performed by applying a voltage between the anode 98 and the anode 98. As a result, the state of the electric field on the surface of the substrate becomes a desired state, and an electrolytic treatment such as electrolytic plating is performed, so that the treatment state by the electrolytic treatment of the surface of the substrate can be set as a target treatment state. .

  Further, as the porous structure 110, the entire electrical resistance value A (Ω) of the porous structure 110 between the upper and lower surfaces in a state where the inside is filled with a plating solution (electrolytic solution) is a seed layer on the surface of the substrate W. You may use what was adjusted to 0.02 times or more (A / B> = 0.02) with respect to the sheet resistance (electrical resistance) value B ((omega | ohm) / square) of (conductive layer) 7.

FIG. 15 is a graph showing another relationship between the plating current flowing between the cathode contact 88 and the anode 98 and the plating time.
That is, in the initial plating period (t _{5 to} t ₆ ), the average cathode for the conductive layer (seed layer 7) in the central portion of the substrate between the cathode contact 88 and the disc-shaped anode 98a located in the central portion. as the electrode density is a _5, passing a first current from the plating power source 114a, no current flows between the ring-shaped anode 98b located cathode contacts 88 and the outer peripheral portion.

From the middle stage to the later stage (t _{6 to} t ₇ ), the conductive layer (seed layer 7) in the central part of the substrate is interposed between the cathode contact 88 and the disc-shaped anode 98a located in the central part. A second current lower than the first current is supplied from the plating power source 114a so that the average cathode electrode density becomes A ₆ (<A ₅ ). At the same time, the average cathode electrode density with respect to the conductive layer (seed layer 7) on the outer peripheral portion of the substrate is A ₉ (A ₈ <A ₉ <A ₇ ) between the cathode contact 88 and the ring-shaped anode 98b located on the outer peripheral portion. ) so as to, from the plating power source 114b, the plating initial (t 5 _{~t 6)} to lower than the first current to flow between the disk-shaped anode 98a positioned at the center and the cathode contact 88, and the plating medium term In the latter period (t _{7 to} t ₈ ), a current higher than the second current that flows between the cathode contact 88 and the disc-shaped anode 98a located in the center is passed.

  This prevents a plating film from being formed on the peripheral edge of the substrate as much as possible in the initial stage of plating, and also forms a plating film in the central portion of the substrate. Thus, the plating rate of the plating film formed on the peripheral portion becomes equal, and a plating film with better in-plane uniformity can be formed.

Similarly to the above, the plating initial _(t 5 ~t _6), the average cathode density _{A 7} to the conductive layer of the central portion of the substrate (seed layer 7), 40 mA / cm ² or more 60 mA / cm ² or less ( 60> A ₁ > 40 (mA / cm ² )), it is preferable to pass a high first current between the cathode contact 88 and the disc-shaped anode 98a located in the center. In addition, the initial plating period (t _{5 to} t ₇ ) is, for example, within 5000 msec after the start of plating, and preferably from 0 to 3000 msec after the start of plating.

  When a disk-shaped cathode 98a having a diameter of 150 mm is used and a copper film is formed on the surface of a ruthenium film (conductive layer) as a seed layer formed on a 300 mm wafer under the conditions (recipe) shown in FIG. The relationship between the wafer (substrate) position and the film thickness of the copper film is shown by a solid line in FIG. In FIG. 16, for reference, the cathode and ruthenium film made of a single plate are opposed to each other under normal conditions, that is, without using a split cathode, and in the presence of the plating solution, The relationship between the wafer position and the copper film thickness when a copper film is formed on the surface of the ruthenium film by supplying a constant current for a predetermined time is indicated by a broken line.

  From FIG. 16, when copper plating is performed on the surface of the ruthenium film of a 300 mm wafer under normal conditions, a copper film having a thicker peripheral part than the central part is formed by the terminal effect. According to this example, it can be seen that a copper film with high in-plane uniformity can be formed.

  A disc-shaped cathode 98a having a diameter of 150 mm is used, and a surface of a ruthenium film (conductive layer) as a seed layer formed on a 300 mm wafer is disposed between the cathode contact 88 and the ring-shaped anode 98b located on the outer peripheral portion. The wafer (substrate) position and the copper film position when the initial copper plating was performed by flowing the plating current only between the cathode contact 88 and the disc-shaped anode 98a located at the center without passing the plating current. The relationship of the film thickness is shown by (●) in FIG. For reference, except for the seal rings 154a and 154b between the upper end surface of the partition plate 150 and the lower surface of the ceiling wall of the housing 94 and between the lower end surface of the partition plate 150 and the upper surface of the porous structure 110, The relationship between the wafer (substrate) position and the film thickness of the copper film when initial copper plating is performed in the same manner as described above is indicated by (x) in FIG.

  From FIG. 17, seal rings 154a and 154b are interposed between the upper end surface of the partition plate 150 and the lower surface of the ceiling wall of the housing 94, and between the lower end surface of the partition plate 150 and the upper surface of the porous structure 110, Sealing between the upper end surface of the partition plate 150 and the lower surface of the ceiling wall of the housing 94 and between the lower end surface of the partition plate 150 and the upper surface of the porous structure 110 with seal rings 154a and 154b allows the plating solution to flow. It can be seen that by reliably blocking, a copper film can be selectively formed in the central portion of the substrate by the initial plating, whereby the effect of using the divided anodes 98a and 98b can be maximized.

  For example, the upper end surface of the partition plate 150 is brought into pressure contact with the lower surface of the ceiling wall of the housing 94, and the lower end surface of the partition plate 150 and the upper surface of the porous structure 110, respectively. Needless to say, the seal ring is not necessarily required when the gap between the lower surface and the lower end surface of the partition plate 150 and the upper surface of the porous structure 110 can be sealed.

  FIG. 18 is a cross-sectional view during electrolytic plating schematically showing a substrate held by an electrode head and a substrate holding part of another electrolytic plating apparatus. The electrolytic plating apparatus shown in FIG. 18 and the electrolytic plating apparatus 12 shown in FIGS. 2 to 12 described above are different from the electrolytic plating apparatus 12 shown in FIG. 2 to FIG. A disc-shaped anode 98 is disposed, and a plating voltage is applied from the plating power source 114 between the anode 98 and the cathode contact 88, and the plating solution in the plating solution chamber 100 is externally supplied from the plating solution discharge port 103. It is in the point which made it discharge to. Other configurations are substantially the same as those of the electroplating apparatus 12 shown in FIGS.

Using the electrolytic plating apparatus shown in FIG. 18, as shown in FIG. 19A, the average cathode electrode density with respect to the conductive layer (seed layer 7) of the substrate from the initial plating stage to the middle stage (t _{8 to} t ₁₀ ). a ₁₀ is, usually, to take for example _{^{10mA / cm 2 (a 10 =}} 10mA / cm 2), the plating later _(t 10 _{~t 11),} the average cathode to the conductive layer of the substrate (seed layer 7) A ruthenium film is formed by flowing a plating current between the cathode contact 88 and the anode 98 so that the density A ₁₁ is higher than the average cathode electrode density A ₁₀ from the initial stage to the middle stage (A ₁₁ > A ₁₀ ). The surface of the seed layer 7 was plated. At this time, as shown in FIG. 20A, cloudiness (Haze) H was observed at the peripheral portion of the plating film formed on the surface of the ruthenium film.

In contrast, as shown in FIG. 19 (b), the plating initial _(t 8 ~t _9), the average cathode density _{A 12} to the conductive layer of the substrate (seed layer 7), usually, for example, 10 mA / It becomes higher than cm ² , for example, 40 mA / cm ² (A ₁₂ ≧ 40 mA / cm ² ), and between the cathode contact 88 and the anode 98 so as to be a normal plating current from the middle stage of plating to the latter stage (t _{9 to} t ₁₁ ). Plating was applied to the surface of the seed layer 7 made of a ruthenium film by passing a plating current therebetween. At this time, as shown in FIG. 20 (b), it was confirmed that no haze was observed at the peripheral portion of the plating film formed on the surface of the ruthenium film, and a glossy surface over the entire surface was obtained. ing.

Initial plating _(t 8 ~t ₉₎ is, for example, within the plating after the start 5000 msec. Within 5000 msec after the start of plating, a current having an average cathode current density of 40 mA / cm ² or more with respect to the conductive layer of the substrate may be allowed to flow a plurality of times.

  FIG. 21 shows an electroplating apparatus according to another embodiment of the present invention. This electrolytic plating apparatus has a cylindrical housing (plating tank) 602 that opens upward and holds a plating solution 600 therein, and a substrate W such as a semiconductor wafer that is detachably held with the surface facing downward. And a rotatable substrate holding part 604 disposed at a position closing the upper end opening of the housing 602. In this example, the substrate W is in contact with a cathode contact (not shown) provided on the substrate holding portion 604 and energized, and the substrate is held in a state where the peripheral portion is sealed with a sealing material (not shown). Held by the unit 604.

  A porous structure 632 is disposed in the upper end opening of the housing 602, and thereby a plating solution chamber 650 is defined in the housing 602. The plating solution chamber 650 is partitioned into two concentric chambers 654a and 654b by a partition plate 652 made of a cylindrical insulating material. A seal such as rubber or Teflon (registered trademark) is provided between the lower end surface of the partition plate 652 and the upper surface of the bottom wall of the housing 602 and between the upper end surface of the partition plate 652 and the lower surface of the porous structure 632. Rings 656a and 656b are interposed. Note that the housing 602 and the partition plate 652 may be integrated.

  In the plating solution chamber 650, an anode 606 is disposed horizontally below the porous structure 632. The anode 606 is composed of two divided anodes, a central disk-shaped anode 606a and a peripheral ring-shaped anode 606b, which are concentrically divided. The disc-shaped anode (divided anode) 606a is arranged in a room 654a located in the center of the plating solution chamber 650, and the ring-shaped anode (divided anode) 606b is a room located around the plating solution chamber 650. 654b. The anode 606 is made of, for example, a copper plate or an aggregate of copper balls.

  The disc-shaped anode (split anode) 606a is electrically connected to the anode of the first plating power source 658a, and the ring-shaped anode (split anode) 606b is electrically connected to the anode of the second plating power source 658b. , 658b are electrically connected to cathode contacts (not shown) provided on the substrate holding portion 604, respectively.

  The bottom of the housing 602 is provided with a pump 608 therein, and is connected to plating solution supply pipes 610a and 610b that branch into two and supply the plating solution 600 to the chambers 654a and 654b of the plating solution chamber 650, respectively. . A plating solution receiver 612 is disposed outside the housing 602. Further, the plating solution that has flowed into the plating solution receiver 612 is returned to the pump 608 from the plating solution return pipe 614.

As a result, the substrate W is disposed on the upper portion of the housing 602 while being held downward by the substrate holding portion 604 and rotated, and a predetermined voltage is applied between each divided anode 606a, 606b and the conductive layer (seed layer 7) of the substrate W. , While the pump 608 is driven to introduce the plating solution 600 into the housing 602, a plating current is caused to flow between each of the divided anodes 606 a and 606 b and the conductive layer (seed layer) of the substrate W. A plating film is formed on the lower surface of W. At this time, the plating solution 600 overflowing the housing 602 is collected by the plating solution receiver 612 and circulated.
Even in this example, a plating film having a uniform film thickness can be formed on the surface of the substrate by performing the same control as described above.

  Although the embodiments of the present invention have been described so far, it is needless to say that the present invention is not limited to the above-described embodiments, and may be implemented in various forms within the scope of the technical idea. For example, the present invention can be applied not only to a 300 mm wafer but also to a next generation wafer.

It is a top view which shows the whole substrate processing apparatus provided with the electrolytic plating apparatus of embodiment of this invention. It is a top view of the electroplating apparatus shown in FIG. It is an expanded sectional view of the board | substrate holding | maintenance part and cathode part of the electroplating apparatus shown in FIG. It is a front view which shows the precoat and collection | recovery arm of the electroplating apparatus shown in FIG. It is a top view of the board | substrate holding | maintenance part of the electroplating apparatus shown in FIG. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is CC sectional view taken on the line of FIG. It is a top view of the cathode part of the electroplating apparatus shown in FIG. It is the DD sectional view taken on the line of FIG. It is a top view of the electrode arm part of the electroplating apparatus shown in FIG. It is sectional drawing at the time of the electroplating which shows schematically the board | substrate hold | maintained with the electrode head and board | substrate holding part of the electroplating apparatus shown in FIG. It is a top view which shows the anode of the electrolytic plating apparatus shown in FIG. 2 is a graph showing a relationship between a plating current flowing between a cathode contact and an anode and a plating time in the electrolytic plating apparatus shown in FIG. It is a graph which shows typically a mode that a plating film grows when the plating current shown in Drawing 13 is sent. 3 is a graph showing another relationship between the plating current flowing between the cathode contact and the anode and the plating time in the electrolytic plating apparatus shown in FIG. 1. The relationship between the wafer (substrate) position and the copper film thickness when a copper film is formed on the surface of the ruthenium film (conductive layer) under the conditions (recipe) shown in FIG. It is a graph which shows the relationship between the wafer (substrate | substrate) position when forming a copper film on the surface of a film | membrane (conductive layer), and the film thickness of a copper film with a broken line, respectively. The relationship between the wafer (substrate) position and the film thickness of the copper film when the initial copper plating is performed on the surface of the ruthenium film (conductive layer) with the electrolytic plating apparatus shown in FIG. It is a graph which shows the relationship between the wafer (substrate | substrate) position and the film thickness of a copper film when initial copper plating is performed on the surface of a ruthenium film (conductive layer) with an apparatus excluding a seal ring from the apparatus, respectively. . It is sectional drawing at the time of the electroplating which shows schematically the board | substrate hold | maintained with the electrode head and board | substrate holding | maintenance part of the other electroplating apparatus. In the electroplating apparatus shown in FIG. 18, the plating time in the case where the electroplating is performed by flowing a high current at the initial stage of plating (a) and the case where the electroplating is performed without flowing the high current in the initial stage of plating (b). It is a graph which shows the relationship between a plating current. In the electroplating apparatus shown in FIG. 18, the plating film in the case where the electroplating is performed by flowing a high current at the initial stage of plating (a) and the case where the electroplating is performed without flowing the high current in the initial stage of plating (b) It is a figure which shows the surface of this. It is a schematic diagram which shows the electrolytic plating apparatus of other embodiment of this invention. It is a figure which shows the example which forms a copper wiring by plating process in order of a process. It is a figure which shows the conventional electrolytic plating apparatus. It is a figure which shows the basic composition of the electroplating apparatus used for this invention.

Explanation of symbols

6 Copper film 7 Seed layer (conductive layer)
DESCRIPTION OF SYMBOLS 10 Load / unload part 12 Electroplating apparatus 20 Substrate processing part 26 Oscillating arm 28 Electrode head 36,604 Substrate holding part 38 Cathode part 40 Anti-scattering cup 68 Substrate stage 70 Support arm 86 Frame 88 Cathode contact 90 Sealing material 94 , 602 Housing 98, 606 Anode 98a, 606a Discoidal anode (split anode)
98b, 606b Ring-shaped anode (split anode)
100, 650 Plating solution chamber 102 Plating solution supply pipe 103a, 103b Plating solution discharge port 104 Plating solution injection part 106 Plating solution discharge tube 110, 632 Porous structure 112 Shield ring 114a, 114b, 658a, 658b Power supply 150, 652 Partition Plate 152a, 152b, 654a, 654b Chamber 154a, 154b, 656a, 656b Seal ring

Claims (8)

A substrate holder for holding the substrate;
A sealing material that comes into contact with the peripheral portion of the substrate surface held by the substrate holding portion and seals the peripheral portion;
A cathode contact for contacting and energizing a conductive layer formed on the surface of the substrate held by the substrate holding unit;
An anode that is immersed in the plating solution is housed therein, and has a housing in which a plating solution chamber is defined by disposing a porous structure at an opening end facing the substrate held by the substrate holding unit,
The plating solution chamber is partitioned by a partition plate and the porous structure, and the anode is composed of a plurality of divided anodes, and each divided anode is independent inside each chamber of the plating solution chamber. An electroplating apparatus characterized by being arranged so that a plating current can flow.   The electroplating apparatus according to claim 1, wherein a seal ring is interposed between the porous structure and the partition plate and / or between the partition plate and the housing.   The anode is composed of split anodes concentrically divided, the split anode located in the center is a disc shape, and the partition plate is formed in a cylindrical shape and surrounds the inner periphery of the split anode. The electroplating apparatus according to claim 1, wherein the electroplating apparatus is arranged so as to perform.   The diameter of the disk-shaped divided anode and the inner diameter of the partition plate arranged so as to surround the disk-shaped divided anode are 2/3 or less of the diameter of the substrate. The electrolytic plating apparatus according to claim 3.   The electroplating according to any one of claims 1 to 4, wherein the conductive layer includes at least one of Cu, Ru, Ta, TaN, W, WNC, WC, Pt, ITO, Ti, and TiW. apparatus. A plating solution is filled between the conductive layer of the substrate in contact with the cathode contact and the divided anode arranged concentrically at the position facing the conductive layer of the substrate,
Placing a porous structure in the plating solution;
An electroplating method, wherein an electric current having a higher current density is passed between the cathode contact and a divided anode located at a central portion at an initial stage of plating than between the cathode contact and another divided anode.   7. The electrolytic plating method according to claim 6, wherein a current lower than that in the initial stage of plating is caused to flow between the cathode contact and the divided anode located in the central portion after the initial stage of plating.   The electroplating method according to claim 6 or 7, wherein no current flows between the cathode contact and the other divided anode in the initial stage of the plating.

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