JP2006225715A - Plating apparatus and plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating apparatus which has a comparatively simple structure but surely forms a metallic film even in a via hole etc. having a high aspect ratio and a deep depth without forming a void in the inner part. <P>SOLUTION: This plating apparatus comprises: a first plating tank 170a for holding a first plating solution and an anode immersed in the solution; a second plating tank 170b for holding a second plating solution having a lower concentration of the metal than in the first plating solution and an anode immersed in the second plating solution; and a holder 160 which can freely move in the path between the first plating tank 170a and the second plating tank 170b, and holds a material to be plated while passing an electric current to the material. The plating method includes sequentially repeating the first step of plating the material held by the holder 160 while contacting it with the first plating solution in the first plating tank 170a, and the second step of plating the material while contacting the material with the second plating solution in the second plating tank 170b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a plating apparatus and a plating method for plating, for example, the surface (surface to be plated) of a substrate, and in particular, copper, silver or the like in a wiring recess such as a fine trench or a via hole provided on the surface of a semiconductor wafer or the like. The present invention relates to a plating apparatus and a plating method used to form a buried wiring by embedding a conductor (wiring material).
The plating apparatus and plating method of the present invention have, for example, a large number of via plugs penetrating vertically inside and are also used for embedding vias when manufacturing interposers or spacers used for so-called three-dimensional mounting of semiconductor chips and the like. Is done.

  In recent years, as a metal material for forming a wiring circuit on a semiconductor substrate, a movement of using copper (Cu) having a low electrical resistivity and a high electromigration resistance instead of aluminum or an aluminum alloy has become prominent. This type of copper wiring is generally formed by embedding copper in a fine 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. 1 shows an example of a conventional electroplating apparatus employing a so-called dip method. The electroplating apparatus includes a plating tank 12a for holding a plating solution therein, and a vertically movable substrate for holding the substrate W in a detachable manner by sealing the periphery of the substrate W in a watertight manner and exposing the surface (surface to be plated). It has a holder 14a. Inside the plating tank 12a, the anode 24 is held vertically by the anode holder 26, and when the substrate W held by the substrate holder 14a is placed at a position facing the anode 24, the anode 24 and the substrate are arranged. An adjustment plate (regulation plate) 28 made of a dielectric material having a central hole 28a is arranged so as to be positioned between W and W.

  As a result, the anode 24, the substrate W, and the adjusting plate 28 are immersed in the plating solution in the plating tank 12a. At the same time, the anode 24 is connected to the anode of the plating power source 32 via the conductive wire 30a and the substrate is connected via the conductive wire 30b. By connecting W to the cathode of the plating power source 32, the metal ions in the plating solution receive electrons from the surface of the substrate W due to the potential difference between the substrate W and the anode 24, and the metal is deposited on the substrate W. A film is formed.

  According to this plating apparatus, the adjusting plate 28 having the central hole 28a is disposed between the anode 24 and the substrate W disposed at a position facing the anode 24, and the adjusting plate 28 is used in the plating tank 12a. By adjusting the potential distribution, the film thickness distribution of the metal film formed on the surface of the substrate W can be adjusted to some extent.

  In a conventional plating apparatus, a material to be plated such as a substrate is generally immersed in a plating solution having the same composition for a predetermined time to form a plating film on the surface of the material to be plated (surface to be plated). For this reason, it is possible to prevent defects such as voids from being generated inside a via hole having a high aspect ratio and a depth of about 10 to 20 μm and a depth of about 70 to 150 μm provided on the surface of the substrate. However, it has been generally difficult to reliably embed the metal film by plating.

  For example, if a metal film is embedded in a via hole having a high aspect ratio of 1 or more and a deep depth by plating, the plating solution cannot reach the bottom of the via hole, and the plating solution near the opening end of the via hole Metal concentration increases. In this state, as shown in FIG. 2, when plating is performed on the surface of the seed layer 44 covering the insulating film 42 provided with the via hole 40 inside, supply of metal ions in the via hole 40 is insufficient, Plating deposition is prioritized in the vicinity of the opening end of the via hole 40 and the opening end is closed with a metal film (plating film) 46, and a void 48 is generated inside the metal film 46 embedded in the via hole 40. End up.

  In electroplating, the plating rate can be increased by increasing the current density during plating. However, simply increasing the current density causes plating burns, plating defects, passivation of the anode surface, and the like, causing plating defects.

  The present invention has been made in view of the above circumstances, and it has a relatively simple configuration, and has a high aspect ratio, and even in a deep via hole or the like, the metal film can be reliably generated without generating voids therein. An object of the present invention is to provide a plating apparatus and a plating method that can be embedded in a metal.

  The invention according to claim 1 includes a first plating tank for holding the first plating solution by immersing the anode in the first plating solution, and a second plating solution having a metal concentration lower than that of the first plating solution. It is possible to move between the second plating tank for immersing and holding the anode in the second plating solution, and between the first plating tank and the second plating tank, so that the material to be plated can be energized. A holder for holding and contacting the first plating solution in the first plating tank and the second plating solution in the second plating tank, respectively, and the material to be plated held by the holder in the first plating tank The plating is characterized in that the first plating treatment performed in contact with the first plating solution and the second plating treatment performed in contact with the second plating solution in the second plating tank are repeated as one cycle. Device.

  For example, as shown in FIG. 3A, when the first plating solution 50a is brought into contact with the surface of the insulating film 42 in which the via hole 40 covered with the seed layer 44 is provided, the first plating solution 50a becomes the via hole 40. Get inside. Then, after the first plating process is performed in this state, the surface of the insulating film 42 is brought into contact with the second plating solution 50b having a metal concentration lower than that of the first plating solution 50a. As shown in (b), the second plating solution 50b having a low metal concentration gradually diffuses into the first plating solution 50a in the via hole 40, whereby the metal concentration of the plating solution located inside the via hole 40 is as follows. It becomes relatively higher than the plating solution in the vicinity of the opening end of the via hole 40. By performing the second plating process in this state, the peripheral wall of the via hole 40 is prevented from being rate-controlled with respect to the vicinity of the opening end portion of the via hole 40 while eliminating the shortage of supply of metal ions inside the via hole 40. A plating film having a uniform film thickness can be formed. For this reason, the first plating process and the second plating process are defined as one cycle. By repeating this cycle, as shown in FIG. 3C, a metal film having no voids inside the via hole 40 (plating) Film) 46 can be embedded.

  According to a second aspect of the present invention, the first plating solution is a copper sulfate plating solution having a copper sulfate pentahydrate concentration of 190 to 250 g / L, and the second plating solution is copper sulfate / 5 water. The plating apparatus according to claim 1, wherein the concentration of the sum is a copper sulfate plating solution having a concentration of 50 to 180 g / L.

  According to a third aspect of the present invention, the first plating treatment is performed by bringing the material to be plated into contact with the first plating solution and applying a voltage between the material to be plated and the anode immersed in the first plating solution. And a material to be plated is brought into contact with a second plating solution having a metal concentration lower than that of the first plating solution, and a voltage is applied between the material to be plated and the anode immersed in the second plating solution. The plating method is characterized in that the second plating treatment is set as one cycle and the cycle is repeated.

  According to a fourth aspect of the present invention, the first plating solution is a copper sulfate plating solution having a copper sulfate pentahydrate concentration of 190 to 250 g / L, and the second plating solution is copper sulfate / 5 water. 4. The plating method according to claim 3, wherein the concentration of the sum is a copper sulfate plating solution having a concentration of 50 to 180 g / L.

  According to the present invention, a metal film (plating film) is prevented from preferentially precipitating at the opening end of a via hole or the like, and even if the via hole has a high aspect ratio and a deep embedding depth, The film can be reliably embedded without generating voids inside.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiment, an example in which a substrate such as a semiconductor wafer is used as a material to be plated will be described.
FIG. 4 shows an overall layout diagram of the plating processing equipment provided with the plating apparatus in the embodiment of the present invention. This plating processing equipment is configured to automatically and continuously perform all steps of substrate pre-treatment, plating treatment and post-plating treatment. The interior of the apparatus frame 110 to which the exterior panel is attached is a partition plate. 112 is divided into a plating space 116 for performing the plating process on the substrate and the substrate to which the plating solution adheres, and a clean space 114 for performing other processes, that is, a process not directly related to the plating solution.

  Two substrate holders 160 (see FIG. 5) are arranged in parallel in the partition portion partitioned by the partition plate 112 that partitions the plating space 116 and the clean space 114, and the substrate holder 160 is placed between the substrate holders 160. A substrate detachment table 162 is provided as a substrate delivery unit for detachment. The clean space 114 is connected to a load / unload port 120 on which a substrate cassette containing substrates is placed and mounted, and the apparatus frame 110 is provided with an operation panel 121.

  Inside the clean space 114, an aligner 122 for aligning the orientation flat or notch of the substrate in a predetermined direction, two cleaning / drying devices 124 for cleaning the substrate after plating and rotating it at high speed for spin drying, Pre-treatment of the substrate, in this example, spraying pure water toward the surface of the substrate (surface to be plated) to clean the substrate surface with pure water and also wet with pure water to improve hydrophilicity The pre-processing device 126 that performs is arranged at the four corners. Further, these processing devices, that is, the aligner 122, the cleaning / drying device 124, and the pre-processing device 126 are positioned substantially at the center, and the processing devices 122, 124, 126, the substrate detachment table 162, and the load A first transfer robot 128 that transfers and transfers the substrate to and from the substrate cassette mounted on the unload port 120 is disposed.

  The aligner 122, the cleaning / drying device 124, and the pretreatment device 126 arranged in the clean space 114 hold and process the substrate in a horizontal posture with the surface facing upward. The first transfer robot 128 holds the substrate in a horizontal posture with the surface facing upward, and transfers and transfers the substrate.

  In the plating space 116, in order from the partition plate 112 side, a stocker 164 for storing and temporarily placing the substrate holder 160, for example, an oxide film having a high electrical resistance on the surface of the seed layer formed on the surface of the substrate is sulfuric acid, hydrochloric acid, or the like. An activation processing device 166 for etching and removing with a chemical solution, a first water washing device 168a for washing the surface of the substrate with pure water, a first plating device 170a for performing a first plating treatment with the first plating solution, and a first plating device with a second plating solution. A second plating apparatus 170b that performs two plating processes, a second water washing apparatus 168b, and a blow apparatus 172 that drains the substrate after the plating process are arranged in this order. Two second transfer robots 174 a and 174 b are disposed along the rails 176 so as to be located on the side of these devices. The one second transfer robot 174 a transfers the substrate holder 160 between the substrate attaching / detaching table 162 and the stocker 164. The other second transfer robot 174b includes a substrate holder 164, an activation processing device 166, a first water washing device 168a, a first plating device 170a, a second plating device 170b, a second water washing device 168b, and a blow device 172. 160 is conveyed.

  As shown in FIG. 5, the second transfer robots 174 a and 174 b include a body 178 extending in the vertical direction, and an arm 180 that can move up and down along the body 178 and can rotate about the axis. The arm 180 is provided with two substrate holder holding portions 182 that detachably hold the substrate holder 160 in parallel. The substrate holder 160 is configured to detachably hold the substrate W with the surface exposed and the peripheral edge sealed.

  The stocker 164, the activation processing device 166, the rinsing devices 168 a and 168 b, and the plating devices 170 a and 170 b hook the protrusions 160 a that protrude outwardly provided at both ends of the substrate holder 160 to the upper end portion, and Support in a state suspended in the vertical direction. The activation processing apparatus 166 includes two activation processing tanks 183 that hold a chemical solution therein, and as shown in FIG. 5, the second transfer that holds the substrate holder 160 loaded with the substrate W in a vertical state. The arm 180 of the robot 174b is lowered, and the substrate holder 160 is hooked on the upper end portion of the activation treatment tank 183 and supported by being suspended, so that the substrate holder 160 and the substrate W are immersed in the chemical solution in the activation treatment tank 183. An activation process is performed.

  Similarly, each of the water washing apparatuses 168a and 168b includes two washing tanks 184a and 184b each holding pure water therein, and the first plating apparatus 170a includes the first plating solution 50a (FIG. 3A). Etc.) and the second plating apparatus 170b includes a plurality of second plating tanks 186b each holding a second plating solution 50b (see FIG. 3B). Is provided. Then, in the same manner as described above, the substrate holder 160 and the substrate W are immersed in pure water in these washing tanks 184a and 184b or in the plating solutions 50a and 50b in the plating tanks 186a and 186b, so that washing treatment and plating treatment are performed. Configured to be done. The blower 172 lowers the arm 180 of the second transfer robot 174b that holds the substrate holder 160 with the substrate W mounted thereon in a vertical state, and blows air or an inert gas onto the substrate W mounted on the substrate holder 160. Thus, the substrate is blown.

  As the second plating solution 50b, a plating solution having a metal concentration lower than that of the first plating solution 50a is used. For example, when copper plating is performed, as the first plating solution 50a, for example, a copper sulfate plating solution (high concentration bath) having the following composition has a copper concentration higher than that of the first plating solution 50a as the second plating solution 50b. A low, for example, copper sulfate plating solution (low concentration bath) having the following composition is used.

Composition of first plating solution (high concentration bath) Copper sulfate pentahydrate: 190-250 g / L
Sulfuric acid: 10-200 g / L
Chlorine: 30-80 mg / L
Additive: Optional
Composition of second plating solution (low concentration bath) Copper sulfate pentahydrate: 50 to 180 g / L
Sulfuric acid: 10-200 g / L
Chlorine: 30-80 mg / L
Additive: Optional

The first plating apparatus 170a and the first plating tank 186a, and the second plating apparatus 170b and the second plating tank 186b have the same configuration except for the plating solution used. Here, the first plating apparatus 170a and the first plating tank 186a will be described.
As shown in FIG. 6, each first plating tank 186 a of the first plating apparatus 170 a has a fixed amount of the first plating solution 50 a (in each second plating tank 186 b of the second plating apparatus 170 b, 2 is configured to hold the plating solution 50b), and the substrate W is held in the first plating solution 50a with the substrate holder 160 sealed in a watertight manner to expose the surface (surface to be plated). To be arranged.

  On the side of the first plating tank 186a, there is provided an overflow tank 202 for flowing the first plating solution 50a overflowing the upper end of the overflow weir 200 of the first plating tank 186a. A discharge line 204 is connected. A circulation pump 208, a flow rate regulator 210, and a filter 212 are interposed inside a plating solution circulation line 206 that connects the plating solution discharge line 204 and the plating solution supply line 218. As a result, the first plating solution 50a supplied into the first plating tank 186a as the circulation pump 208 is driven fills the inside of the first plating tank 186a, and then overflows from the overflow weir 200 and overflows. It flows into the tank 202 and returns to the circulation pump 208 for circulation. Moreover, the flow rate of the first plating solution 50 a flowing along the plating solution circulation line 206 is adjusted by the flow rate regulator 210.

  Inside the first plating tank 186a, a disc-shaped anode 214 along the shape of the substrate W is held by an anode holder 216 and installed vertically. The anode 214 is immersed in the first plating solution 50a when the first plating bath 186a is filled with the first plating solution 50a, and is held by the substrate holder 160 to be in a predetermined position in the first plating bath 186a. It faces the substrate W arranged on the surface.

  Further, a ring connected to the plating solution supply line 218 is located in the first plating tank 186a between the anode 214 and the substrate holder 160 disposed at a predetermined position in the first plating tank 186a. The nozzle piping 220 is arranged. The nozzle pipe 220 is formed in a ring shape along the outer shape of the substrate W, and a plurality of plating solution spray nozzles 222 are arranged at a predetermined pitch at a predetermined position along the circumferential direction of the nozzle pipe 220. Is provided. As a result, the first plating solution 50a circulating as the circulation pump 208 is driven as described above is sprayed from the plating solution spray nozzle 222 and supplied into the first plating tank 186a.

  In this example, the nozzle pipe 220 has an opening 224a inside, and is fixed to a rectangular flat plate-like fixing plate 224 that partitions the inside of the first plating tank 186a into the anode side and the substrate side via a stopper 226. . The size of the opening 224a is set to be approximately the same as or slightly smaller than the inner diameter of the nozzle pipe 220, and the nozzle pipe 220 is located on the substrate side of the fixed plate 224 so as to surround the periphery of the opening 224a. Has been placed. Then, the plating solution spray nozzle 222 is configured so that the first plating solution 50a sprayed from the plating solution spray nozzle 222 is held by the substrate holder 160 and is disposed at a predetermined position in the first plating tank 186a. It is arranged in the direction of merging at the merging point P substantially before the center.

  As a result, the first plating solution 50a is injected from the plating solution injection nozzle 222 provided in the ring-shaped nozzle pipe 220, and is supplied and circulated into the first plating tank 186a. At this time, the first plating solution 50a is sprayed from the plating solution spray nozzle 222 toward the surface (surface to be plated) of the substrate W, and a strong jet of the first plating solution 50a is applied to the entire surface of the substrate W. It is possible to increase the plating rate without deteriorating the plating film quality by efficiently supplying the ions in the first plating solution 50a to the surface of the substrate W while suppressing the disturbance of the uniformity of the potential distribution. Moreover, the surface of the substrate W is adjusted by adjusting the flow rate and direction of the first plating solution 50a sprayed from the plating solution spray nozzle 222 so that the flow of the first plating solution 50a in the vicinity of the surface of the substrate W becomes more uniform. It is possible to improve the uniformity of the thickness of the plating film formed on the substrate.

  In particular, it is preferable that the first plating solution 50a sprayed from the plating solution spray nozzle 222 joins at a confluence point P approximately before the center of the surface of the substrate W. Thereby, the flow of the merged first plating solution 50a becomes a flow perpendicular to the center of the surface of the substrate W, and then the direction is changed to a flow that spreads outward along the surface of the substrate W. The flow after the first plating solution 50a collides with the surface of the substrate W is prevented from interfering with the discharge flow of the first plating solution 50a, and a constant continuous flow of the first plating solution 50a is formed. be able to.

  The nozzle pipe 220, the plating solution injection nozzle 222, and the fixing plate 224 are preferably made of a dielectric made of, for example, PVC, PP, PEEK, PES, HT-PVC, PFA, PTFE, or other resin materials. . Thereby, it is possible to prevent the electric field distribution in the first plating tank 186a from being disturbed by these existences.

  Furthermore, the inside of the first plating tank 186a is partitioned by the fixing plate 224 provided with the opening 224a, and the first plating solution 50a overflows from the overflow tank 202 after passing through the opening 224a. The potential distribution over the entire area of W can be made more uniform.

  The first plating apparatus 170a is provided with a plating power source 230 in which the anode is connected to the anode 214 via the conductor 228a and the cathode is connected to the substrate W via the conductor 228b during plating. The plating power source 230 is connected to the control unit 250, and is configured to change a voltage applied between the anode 214 and the substrate W during plating based on a signal from the control unit 250. The same applies to the second plating apparatus 170b.

  According to the first plating apparatus 170a, first, the first plating solution 50a is filled in the first plating tank 186a. Then, the substrate holder 160 holding the substrate W is lowered, and the substrate W is disposed at a predetermined position immersed in the first plating solution 50a in the first plating tank 186a. In this state, the circulation pump 208 is driven to inject the first plating solution 50a from the plating solution injection nozzle 222 toward the surface of the substrate W and supply the first plating solution 50a into the first plating tank 186a. Circulate. Then, the plating power source 230 is controlled by a signal from the control unit 250 and the voltage applied between the anode 214 and the substrate W is adjusted, so that a metal is deposited on the surface of the substrate W to form a metal film.

  At this time, as described above, by plating the first plating solution 50a from the plating solution spray nozzle 222 toward the surface (surface to be plated) of the substrate W and applying a strong jet of the first plating solution 50a, plating is performed. The plating rate can be increased without deteriorating the film quality. Moreover, the uniformity of the thickness of the plating film formed on the surface of the substrate W can be improved by adjusting the flow of the first plating solution 50a near the surface of the substrate W to be more uniform.

A series of plating processes for forming the copper wiring by the plating apparatus constructed as described above will be described with further reference to FIG. First, as shown in FIG. 7A, an insulating film 2 such as an oxide film made of SiO ₂ or a low-k material film is deposited on a conductive layer 1a on a semiconductor substrate 1 on which a semiconductor element is formed, Via holes 3 and trenches 4 are formed as recesses for wiring inside the insulating film 2 by lithography / etching technique, and a barrier layer 5 made of Ta, TaN, TiN, WN, SiTiN, CoWP, CoWB or the like is formed thereon. Further, a substrate W on which a seed layer (conductive layer) 7 is formed as a power feeding layer for electrolytic plating is prepared. Then, this substrate W is accommodated in a substrate cassette with its surface (surface to be plated) facing up, and this substrate cassette is mounted on the load / unload port 120.

  One substrate W is taken out from the substrate cassette mounted on the load / unload port 120 by the first transfer robot 128 and placed on the aligner 122 so that the orientation flat, notch, etc. are aligned in a predetermined direction. The substrate W whose direction is adjusted by the aligner 122 is transferred to the pretreatment apparatus 126 by the first transfer robot 128. Then, in this pretreatment device 126, pretreatment using pure water (pretreatment with water washing) is performed on the pretreatment liquid. On the other hand, the substrate holder 160 stored in the vertical position in the stocker 164 is taken out by the second transfer robot 174a, and the substrate holder 160 is rotated 90.degree. And placed in parallel on the substrate attachment / detachment table 162.

  Then, the substrate W that has been subjected to the above-described pretreatment (pretreatment with water washing) is mounted on the substrate holder 160 placed on the substrate detachment table 162 with its peripheral edge sealed. Then, the two substrate holders 160 loaded with the substrate W are simultaneously gripped by the second transport robot 174a, lifted, transported to the stocker 164, and rotated 90 ° to bring the substrate holder 160 into a vertical state. Thereafter, it is lowered, and the two substrate holders 160 are suspended and held (temporarily placed) on the stocker 164. This is repeated sequentially, and the substrate is sequentially mounted on the substrate holder 160 housed in the stocker 164, and is suspended and temporarily held (temporarily placed) at a predetermined position of the stocker 164.

  On the other hand, in the second transfer robot 174b, two substrate holders 160, which are mounted with substrates and temporarily placed on the stocker 164, are simultaneously gripped and raised, and then transferred to the activation processing device 166 to be activated. The substrate is immersed in a chemical solution such as sulfuric acid or hydrochloric acid placed in 183 to etch the oxide film having a large electrical resistance on the surface of the seed layer, thereby exposing a clean metal surface. Further, the substrate holder 160 mounted with the substrate is transported to the first water washing device 168a in the same manner as described above, and the surface of the substrate is washed with pure water placed in the water washing tank 184a.

  In the same manner as described above, the substrate holder 160 mounted with the substrate that has been washed with water is transferred to the first plating apparatus 170a, and the first plating solution 50a in the first plating tank 186a is immersed in the first plating solution 50a. A first plating solution (high concentration bath) 50a is applied to the surface of the substrate W by being supported by being suspended in the plating tank 186a and applying a voltage between the substrate W and the anode 214 in the first plating tank 186a. Apply processing. Then, after performing the first plating process for a predetermined time, the substrate holder 160 on which the substrate is mounted is pulled up from the first plating solution 50a in the first plating tank 186a and conveyed to the second plating apparatus 170b. Then, the substrate holder 160 is suspended and supported in the second plating tank 186b while the substrate is immersed in the second plating solution 50b in the second plating tank 186b, and the substrate W and the anode 214 in the second plating tank 186b A voltage is applied between the surfaces of the substrate W and the second plating treatment with the second plating solution (low concentration bath) 50b having a lower copper concentration than the first plating solution (high concentration bath) 50a.

The first plating process using the first plating solution 50a of the first plating apparatus 170a and the second plating process using the second plating solution 50b of the second plating apparatus 170b are set as one cycle, and this cycle is repeated a predetermined number of times to perform the plating process. To complete.
For example, when copper is buried in a trench having a width of 20 μm, the first plating treatment with the first plating solution 50a having the above-described composition of the first plating apparatus 170a and the second composition having the above-described composition of the second plating apparatus 170b are performed. When a copper film (plating film) having a thickness of 1 μm can be obtained by one cycle of the second plating process using the two plating solutions 50b, this cycle is repeated 10 times.

  By this one-cycle plating process, a second plating process is performed in which the copper concentration of the plating solution located inside the via hole 3 or the trench 4 is relatively higher than the plating solution near the opening end of the via hole 3 or the trench 4. be able to. As a result, the shortage of supply of copper ions inside the via hole 3 or the trench 4 is solved, and the peripheral wall of the via hole 3 or the trench 4 is prevented from becoming the reaction rate controlling near the opening end portion of the via hole 3 or the trench 4. A plating film (copper film) having a uniform film thickness can be formed. Then, by repeating this cycle a predetermined number of times, as shown in FIG. 7B, a copper film (plating film) 6 having no voids can be embedded in the via hole 3 and the trench 4.

  After the end of the plating process, the substrate holder 160 is pulled up from the second plating solution 50b in the second plating tank 186a of the second plating apparatus 170b, and is transported to the second water washing apparatus 168b in the same manner as described above, and this water washing tank 184b. The surface of the substrate is washed with pure water by immersing it in pure water. Thereafter, the substrate holder 160 mounted with the substrate is transported to the blower 172 in the same manner as described above, and here, an inert gas or air is blown toward the substrate to adhere the plating solution attached to the substrate holder 160. Remove water drops. Thereafter, the substrate holder 160 with the substrate mounted thereon is returned to a predetermined position of the stocker 164 and held in the same manner as described above.

The second transfer robot 174b sequentially repeats the above operations, and returns the substrate holder 160, on which the plated substrate is mounted, to the predetermined position of the stocker 164 in a suspended manner.
On the other hand, in the second transfer robot 174a, the two substrate holders 160 to which the plated substrate is mounted and returned to the stocker 164 are simultaneously grasped and placed on the substrate detachment table 162 in the same manner as described above. .

  Then, the first transfer robot 128 disposed in the clean space 114 takes out the substrate from the substrate holder 160 placed on the substrate attachment / detachment table 162 and transfers it to one of the cleaning / drying devices 124. Then, the substrate held horizontally with the cleaning / drying device 124 is cleaned with pure water or the like, spin-dried by high-speed rotation, and then loaded / removed by the first transfer robot 128. Returning to the substrate cassette mounted on the unload port 120, a series of plating processes is completed. Thereby, as shown in FIG. 7B, a substrate W is obtained in which the via hole 3 and the trench 4 are filled with copper and the copper film 6 is deposited on the insulating film 2.

  The substrate W spin-dried as described above is then transferred to a chemical mechanical polishing (CMP) apparatus, and the copper film 6 and seeds on the insulating film 2 are seeded by chemical mechanical polishing (CMP). The layer 7 and the barrier layer 5 are removed so that the surface of the copper film 6 filled in the via hole 3 and the trench 4 and the surface of the insulating film 2 are substantially flush with each other. Thereby, as shown in FIG. 7C, a wiring made of the copper film 6 is formed.

Next, with reference to FIG. 8, an example of manufacturing an interposer or spacer having a plurality of copper via plugs penetrating vertically inside and below will be described. As shown in FIG. 8A, an insulating film 512 made of SiO ₂ or the like is deposited on the surface of a substrate 510 made of silicon or the like, and a plurality of via holes 514 opened upward are formed therein by, for example, lithography / etching technology. A formed substrate W is prepared. The diameter d of the via hole 514 is, for example, 10 to 20 μm, and the depth h is, for example, 70 to 150 μm. Then, as shown in FIG. 8B, a barrier layer 516 made of TaN or the like is formed on the surface of the substrate W, and a (copper) seed layer 518 as a power feeding layer for electroplating is formed on the surface of the barrier layer 516 by sputtering or the like. Form.

  Then, in the same manner as described above, the first plating process with the first plating solution 50a of the first plating apparatus 170a and the second plating process with the second plating solution 50b of the second plating apparatus 170b are performed on the surface of the substrate W as one. As shown in FIG. 8C, copper (plating film) is filled in the via hole 514 of the substrate W and copper is formed on the surface of the insulating film 512 by performing a plating process that repeats this cycle a predetermined number of times. A film 520 is deposited.

  Thereafter, as shown in FIG. 8D, the excess copper film 520, seed layer 518 and barrier layer 516 on the insulating film 512 are removed by chemical mechanical polishing (CMP) or the like, and at the same time, in the via hole 514. The back side of the substrate 510 is polished and removed until the bottom surface of the copper filled in is exposed to the outside. Thus, an interposer or spacer having a plurality of via plugs 522 made of copper penetrating vertically is completed.

  By performing copper plating using the plating apparatus of the present invention, for example, even in a via hole having a high aspect ratio and a deep depth of about 10 to 20 μm in diameter d and about 70 to 150 μm in depth h, It has been confirmed that copper (plating film) can be embedded without defects such as voids in about 5 hours.

  According to this example, the second transfer robots 174a and 174b in which the delivery of the substrate in the plating space 116 is arranged in the plating space 116, the delivery of the substrate in the clean space 114 is arranged in the clean space 114. Each of the first transfer robots 128 improves the cleanliness around the substrate in the plating processing facility that continuously performs all the plating steps of substrate pretreatment, plating treatment and post-plating treatment, and plating treatment. It is possible to improve the throughput as the facility and further reduce the load on the incidental facility of the plating processing facility, thereby further downsizing the plating processing facility.

  In this example, a plating apparatus having a large number of plating tanks 186a and 186b can be obtained by using a plating apparatus having a small footprint as the plating apparatuses 170a and 170b for performing the plating process. While reducing the size, it is possible to further reduce the load on facilities attached to the factory. Note that one of the two cleaning / drying devices 124 installed in FIG. 4 may be replaced with a pretreatment device.

It is a schematic perspective view which shows an example of the conventional plating apparatus. It is a figure which shows the outline | summary of the embedding state of the metal film when plating with the conventional plating apparatus. (A) shows a state in which the first plating solution is brought into contact with the insulating film surface, and (b) shows a state immediately after being brought into contact with the second plating solution after bringing the first plating solution into contact with the insulating film surface. (C) is a figure which shows the state after embedding by this invention, respectively. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall layout diagram of a plating processing facility provided with a plating apparatus according to an embodiment of the present invention. FIG. 5 is a schematic diagram of a transfer robot provided in the plating space of the plating processing facility shown in FIG. 4. It is a schematic sectional drawing of the plating apparatus with which the plating processing equipment shown in FIG. 4 is equipped. It is a figure which shows one manufacture example of the copper wiring board W in order of a process. It is a figure which shows the manufacture example of the interposer or spacer which has a via plug which consists of several copper penetrated up and down inside in order of a process.

Explanation of symbols

50a, 50b Plating solution 110 Device frame 112 Partition plate 114 Clean space 116 Plating space 120 Load / unload port 122 Aligner 124 Cleaning / drying device 126 Pretreatment device 128 Transfer robot 160 Substrate holder 162 Substrate attachment / detachment table 164 Stocker 166 Activation processing Apparatus 168a, 168b Washing apparatus 170a, 170b Plating apparatus 172 Blow apparatus 174a, 174b Transfer robot 180 Arm 182 Substrate holder holding part 183 Activation treatment tank 184a, 184b Washing tank 186a, 186b Plating tank 202 Overflow tank 204 Plating solution discharge line 206 Plating solution circulation line 208 Circulation pump 210 Flow rate regulator 214 Anode 216 Anode holder 218 Plating solution supply line 220 Nozzle piping 222 Plating solution injection nose 224 fixing plate 230 plating power source 250 control unit

Claims (4)

A first plating bath for holding the first plating solution by immersing the anode in the first plating solution;
A second plating bath for holding a second plating solution having a metal concentration lower than that of the first plating solution by immersing the anode in the second plating solution;
The first plating bath and the second plating in the first plating bath are movable between the first plating bath and the second plating bath, and hold the material to be plated so that current can be passed through the material to be plated. Having holders that are in contact with the second plating solution in the tank,
A first plating process performed by bringing the material to be plated held by the holder into contact with the first plating solution in the first plating tank, and a second plating performed by contacting the material to be plated in the second plating tank. A plating apparatus characterized in that the treatment is repeated as one cycle and the cycle is repeated.   The first plating solution is a copper sulfate plating solution having a copper sulfate pentahydrate concentration of 190 to 250 g / L, and the second plating solution is a copper sulfate pentahydrate concentration of 50 to 180 g / L. The plating apparatus according to claim 1, wherein the plating apparatus is a copper sulfate plating solution of L.   A first plating treatment in which a material to be plated is brought into contact with a first plating solution, and a voltage is applied between the material to be plated and the anode immersed in the first plating solution; A second plating treatment is performed in one cycle by contacting a second plating solution having a metal concentration lower than that of the plating solution and applying a voltage between the material to be plated and the anode immersed in the second plating solution. A plating method characterized by repeating the cycle.   The first plating solution is a copper sulfate plating solution having a copper sulfate pentahydrate concentration of 190 to 250 g / L, and the second plating solution is a copper sulfate pentahydrate concentration of 50 to 180 g / L. The plating method according to claim 3, wherein the plating solution is a copper sulfate plating solution of L.

Images