JP2003073846A - Apparatus and method for plating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate plating by adopting a face-up system which easily removes generated hydrogen during plating from a surface to be plated, and furthermore form a more uniform plating film on the surface of a material to be treated. SOLUTION: The plating apparatus comprises a plating tank 14 having an opening in the upper part, for holding a heated plating solution 12, a holding part 16 which is arranged in a location covering up the upper opening part of the plating tank 14, seals the back side and a periphery of the workpiece W to be treated, and holds the workpiece W so as to direct the exposed surface to be plated upward, and a means 52 for immersing the workpiece W held by the holding part 16 into the plating solution 12 in the plating tank 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus and a plating method, and in particular, a fine wiring recess provided on the surface of a substrate such as a semiconductor substrate is filled with a conductor such as copper or silver to form a buried wiring. The present invention relates to an electroless plating apparatus and a plating method used for forming and forming a protective film for protecting the surface of the wiring thus formed.

[0002]

2. Description of the Related Art Electroless plating is a method in which metal ions in a plating solution are chemically reduced to form a plating film on a surface to be plated of a material to be processed without applying electricity from the outside. It is widely used for corrosion- and wear-resistant nickel-phosphorus, nickel-boron plating, and copper plating for printed wiring boards.

As this electroless plating apparatus, a plating tank for holding an electroless plating solution and a plating tank which is arranged above the plating tank and faces a material to be treated such as a substrate downward (face down)
It has a holding part that can be moved up and down and is held by this holding part so that the material to be processed is immersed in the plating solution in the plating tank, or the material to be processed such as the substrate faces up (face-up). ), And a plating solution supply section (nozzle) for supplying the electroless plating solution to the upper surface (surface to be plated) of the material to be processed held by this retention section. A device in which an electroless plating solution is made to flow along the upper surface of a material to be processed is generally known.

With the recent increase in speed and integration of semiconductor chips, as a metal material for forming a wiring circuit on a semiconductor substrate, aluminum or aluminum alloy has been replaced with low electric resistivity and high electromigration resistance. The movement of using copper (Cu) has become remarkable. This kind of copper wiring is generally formed by embedding copper inside the fine recesses provided on the surface of the substrate. As a method of forming this copper wiring, there are techniques such as CVD, sputtering and plating, but plating is common.
In any case, after forming a copper layer on the surface of the substrate, the surface is polished flat by chemical mechanical polishing (CMP).

In this type of wiring, the surface of the wiring is exposed to the outside after being flattened, and when a buried wiring is formed thereon, for example, SiO ₂ in the next step of forming an interlayer insulating film. During surface oxidation during formation and SiO ₂ etching for forming contact holes, there is concern about surface contamination due to etchant of the wiring exposed at the bottom of the contact hole, resist peeling, and copper diffusion in copper wiring. Has been done.

Therefore, the surface of the wiring is selectively coated with a protective film (plating film) made of, for example, a Ni--B alloy film, which has a strong bond with a wiring material such as silver or copper and has a low specific resistance (ρ). It may be possible to cover it by protecting it. Where Ni-B
The alloy film is formed of, for example, copper by subjecting it to electroless plating using an electroless plating solution containing nickel ions, a complexing agent for nickel ions, an alkylamine borane as a reducing agent for nickel ions, or a borohydride compound. Can be selectively formed on the surface of.

[0007]

Electroless plating is applied to a main filling material (Cu) of copper wiring, formation of a seed layer on a barrier metal, or reinforcement of seed (Cu).
Further, the barrier metal itself is formed, and the copper wiring material is formed as a lid material (all are Ni-P, Ni-B, Co-P, Ni-
WP, Ni-Co-P, Co-WP, Co-W-
B) and the like, but in any electroless plating process, the uniformity of the film thickness is required over the entire surface of the material to be treated.

In electroless plating, the material to be treated comes into contact with the electroless plating solution and at the same time the plating metal is deposited on the surface to be plated, and the deposition rate of the plating metal varies depending on the temperature of the plating solution. Therefore, in order to form a plating film with a uniform film thickness on the plated surface of the material to be processed, the temperature of the plating solution is uniform over the entire surface of the surface to be plated from the beginning when the plating solution contacts the material to be processed. Therefore, it is required to keep this temperature constant throughout the entire plating process during contact.

However, the conventional electroless plating apparatus generally holds a material to be processed such as a substrate in close contact with the upper surface or the lower surface of a holding portion containing a heater, and heats the material to be processed through the heater. The surface to be plated of the material to be treated is brought into contact with the electroless plating solution heated to a predetermined temperature. For this reason, due to the unevenness of the material to be processed and the surface roughness of the holding part, an air pool is generated between the material to be processed and the holding part, and this air pool acts as a heat insulating material. There is a large variation in heat conduction between the material to be treated and the holding part, and moreover, a sheet of Teflon (trademark) or the like having poor thermal conductivity is generally attached to the surface of the holding part. There was a problem in temperature uniformity because the temperature on the entire surface of the material to be treated was not uniform.

That is, the rate and film quality of electroless plating are
It largely depends on the temperature of the electroless plating solution, and in order to ensure the uniformity of the film thickness over the entire surface of the material to be treated, the temperature of the plating solution should be within ± 1 ° C over the entire surface of the material to be treated. Control is desired. However, for example, in an electroless plating apparatus that employs a face-down method, the holding member that holds the material to be processed is at room temperature before plating, so at the initial stage of plating, the area where the material to be processed comes into contact with the holding member is locally affected. The conventional electroless plating apparatus has a problem that it is difficult to maintain the predetermined temperature of the plating solution reaching the surface to be plated in the electroless plating apparatus that adopts the face-up method. However, it was difficult to meet this requirement because the temperature of the plating solution that comes into contact with the material to be treated during plating varied by about ± 5 ° C. As described above, the temperature is not uniform on the entire surface of the material to be processed, and there is a problem in temperature uniformity, which is the same in the electrolytic plating apparatus.

Further, in the electroless plating apparatus adopting the face-down system, hydrogen generated during plating is hard to be separated from the surface to be plated, so that not only plating is not possible but also the plating quality depends on the plating flow rate. It has a problem that it is sensitively affected by flow factors such as the number of revolutions of the material to be treated and the number of revolutions of the material to be treated. In addition, in the electroless plating apparatus that adopts the face-up method, the plating quality is determined by the plating solution supply unit There was a problem that it was sensitive to the movement of).

The present invention has been made in view of the above, and employs a face-up system in which hydrogen generated during plating is easily separated from the surface to be plated, and plating is easy, and the surface to be plated of the material to be processed is adopted. It is an object of the present invention to provide a plating apparatus and a plating method capable of easily forming a uniform plating film.

[0013]

According to a first aspect of the present invention, there is provided a plating tank which is opened upward and holds a heated plating solution, and a position which covers an upper end opening of the plating tank and which is to be treated. A holding portion for sealing the back surface and outer peripheral portion of the material to expose the surface to be plated and holding the material to be processed facing upward, and means for immersing the material to be processed held by the holding portion in the plating solution in the plating tank It is a plating apparatus characterized by having. As a result, the so-called face-up method is adopted, and the material to be processed is immersed in the plating solution for plating while the back surface and outer peripheral portion of the material to be processed are sealed, so that hydrogen generated during plating can be easily generated. It is possible to separate from the surface to be plated and perform stable plating.

According to a second aspect of the invention, the holding portion is
It has a stage and a holder that can move up and down relatively, the back surface of the material to be processed is covered with the stage, and the peripheral edge of the plated surface of the material to be processed is sealed with a sealing material provided in the holder to be processed. The plating apparatus according to claim 1, which holds a material.

According to a third aspect of the present invention, the stage has a ring-shaped support frame and a thin-film heat conductor stretched inside the support frame.
It is the described plating apparatus. With this, when the material to be processed is held in the holding part, when the material to be processed is immersed in the plating solution, the heat of the plating solution is conducted from the thermal conductor to the material to be processed held in the holding part and heated. be able to. Here, as the heat conductor, a thin-walled one is used so that the heat conductor follows the irregularities on the back surface of the material to be processed, thereby increasing the contact area and efficiently conducting heat to the material to be processed. By using the fluid having a large heat capacity as the heat source, the material to be treated can be heated more uniformly in a short time.

According to a fourth aspect of the invention, the holding portion is
The preheating position is movable up and down with respect to the plating tank, and the heat conductor is brought into contact with the plating solution in the plating tank to preheat the material to be processed held by the holding portion, and the material to be processed is plated with the material. The plating apparatus according to claim 3, wherein the plating apparatus is immersed in a plating solution in the bath and stopped at a plating position where plating is performed. With this, the holding part holding the material to be processed is stopped at the preheating position, preheated until the temperature of the material to be processed becomes stable, and after the temperature of the material to be processed becomes stable, the holding part is moved to the plating position. By performing plating, it is possible to prevent a delay in local temperature rise in the material to be processed.

According to a fifth aspect of the present invention, in the plating tank, a plating solution is introduced into the plating tank from the bottom of the plating tank.
The plating apparatus according to any one of claims 1 to 4, wherein the plating solution is configured to overflow from the upper portion of the plating tank. As a result, the plating solution in which the concentration of each component and the solution temperature are adjusted can be sequentially introduced into the plating tank and discharged.

According to a sixth aspect of the present invention, an upper opening is provided,
A plating bath that holds the heated plating solution, a holding unit that is placed at a position that covers the upper end opening of the plating bath and that holds the material to be treated by sealing the peripheral edge of the plating target surface, and the holding unit Means for immersing the processed material in a plating solution in the plating tank, a chamber that hermetically surrounds the upper part of the plating tank, and an inert gas introducing means for introducing an inert gas into the chamber. It is a plating apparatus characterized by having. As described above, the inert gas atmosphere can eliminate the influence of the dissolved oxygen concentration of the plating solution on the plated film. This inert gas is N ₂ gas, for example.

According to a seventh aspect of the invention, the material to be treated is held by a holding portion, the material to be treated held by the holding portion is heated by a plating solution held in a plating tank, and the heated material to be treated is held. Is immersed in a plating solution in a plating tank for plating. In the invention according to claim 8, the material to be processed is placed and held upward on the upper surface of the heat conductor,
The plating method according to claim 7, wherein the material to be treated is heated by bringing the thermal conductor into contact with a plating solution in a plating tank.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of copper wiring formation in a semiconductor device in the order of steps. First, as shown in FIG. 1A, SiO ₂ is formed on a conductive layer 1a on a semiconductor substrate 1 on which a semiconductor element is formed. An insulating film 2 is deposited, and a contact hole 3 and a wiring groove 4 are formed in the insulating film 2 by, for example, a lithographic etching technique.
A barrier layer 5 made of TaN or the like is further formed thereon, and a copper seed layer 6 as a power feeding layer for electrolytic plating is further formed thereon by sputtering or the like.

Then, as shown in FIG. 1B, the surface of the semiconductor substrate W is copper-plated to fill the contact holes 3 and the grooves 4 of the semiconductor substrate W with copper, and the insulating film 2 A copper layer 7 is deposited on. Then, the copper layer 7 on the insulating film 2 is removed by chemical mechanical polishing (CMP), and the surface of the copper layer 7 filled in the contact hole 3 and the wiring groove 4 and the surface of the insulating film 2 are removed. Are almost in the same plane. As a result, as shown in FIG. 1C, the insulating film 2
A wiring 8 composed of a copper seed layer 6 and a copper layer 7 is formed inside. Next, for example, electroless Ni-B plating is applied to the surface of the substrate W, and as shown in FIG. 1D, a protective film (plating film) 9 made of a Ni-B alloy film is formed on the exposed surface of the wiring 8. Are selectively formed to protect the wiring 8.

2 and 3 show an electroless plating apparatus according to an embodiment of the present invention. This electroless plating apparatus is used, for example, for forming the barrier layer 5 in FIG. 1, reinforcing the copper seed layer 6, depositing the copper layer 7, and further forming the protective film (plating film) 9. The electroless plating apparatus 10 has a plating tank 14 that opens upward and holds a plating solution 12 therein.
And a substrate holding part 16 arranged at the upper end opening of the plating tank 14 and holding a substrate (material to be processed) W such as a semiconductor wafer with the surface (plating surface) of the substrate W facing upward (face up). have.

The plating tank 14 has a plating solution introduction hole 18 at the center of the bottom of the tank, and the plating solution introduction hole 18 is connected to a plating solution supply pipe 20. The plating solution supply pipe 20 is provided with a heater 22 that heats the plating solution 12 passing through the inside to a predetermined temperature, for example, 60 ° C. An overflow weir 24 is provided above the plating tank 14,
A plating solution discharge passage 26 is formed outside the overflow weir 24. The plating solution discharge path 26 extends through the plating tank 14 in the vertical direction.
Is in communication with.

As a result, the plating solution 12 is introduced into the plating tank 14 from the plating solution supply pipe 20, and is heated to a predetermined temperature by the heater 22 in the process of this introduction.
Then, when the plating 12 in the plating tank 14 reaches a predetermined amount, the plating solution 12 overflows the overflow weir 24 and flows into the plating solution discharge passage 26, and the plating solution discharge hole 28.
Is discharged from the outside. The temperature of the plating solution 12 is, for example, 25 to 90 ° C, preferably about 55 to 85 ° C, more preferably about 60 to 80 ° C.

The substrate holder 16 is mainly composed of a substrate stage 30 and a substrate holder 32. The substrate stage 30 has a substantially cylindrical housing 34 and a ring-shaped support frame 36 connected to the lower end of the housing 34. Further, inside the support frame 36, a thin film heat conductor 38 is provided. The peripheral portion of the heat conductor 38 is attached to the support frame 36 and stretched. On the upper surface of the support frame 36, the support frame 3
When the substrate W is supported by 6, a protrusion 40 having a tapered surface 40a that guides the substrate W on its inner peripheral surface is provided, and the inner diameter of the support frame 36 is the same as that of the substrate W supported by the support frame 36. It is set slightly smaller than the outer diameter. Furthermore, the support frame 3
The upper surface of the heat conducting body 38 and the upper surface of the heat conducting body 38 located on the inner side of the protruding portion 40 of No. 6 are flush with each other. In addition, a through hole 42 penetrating vertically is provided outside the protrusion 40 of the support frame 36.
Is provided.

On the other hand, the substrate holder 32 includes the substrate stage 3
0 has a cylindrical tubular body 44 disposed inside the housing 34, and an inwardly extending ring-shaped pawl portion 46 connected to the lower end of the tubular body 44. When the substrate W is supported by the support frame 36 of the substrate stage 30 on the lower surface, the ring-shaped sealing materials 48a and 48b are concentrically arranged at a position corresponding to the peripheral edge of the substrate W and a position corresponding to the upper surface of the protrusion 40. Installed. Further, at a predetermined position along the height direction of the tubular body 44, a communication hole 50 communicating with the inside and the outside is formed.
Is provided.

Further, a disk-shaped support member 54 which moves up and down and rotates as the motor 52 is driven is provided.
4 are connected, and the substrate holder 32 is attached to the support 54.
An up-and-down moving cylinder 56 for moving up and down is attached. As a result, with the operation of the vertical movement cylinder 56,
The substrate holder 32 vertically moves relative to the substrate stage 30, and the substrate stage 30 and the substrate holder 32 integrally move vertically as the motor 52 is driven.

According to the substrate holder 16, the substrate W is dropped and placed on the upper surface of the support frame 36 of the substrate stage 30 with the substrate holder 32 raised relative to the substrate stage 30. Then, in this state, the substrate holder 32 is lowered relative to the substrate stage 30, so that the peripheral edge portion of the substrate W holding the sealing materials 48a and 48b by the support frame 36 and the upper surface of the protrusion 40 of the support frame 36. It is possible to hold the substrate W by making pressure contact with each other and sealing the outer peripheral portion and the back surface of the substrate W. Then, in this way, the substrate holding unit 1
With the substrate W being held by 6, the substrate holding unit 16 can be moved up and down and rotated via the motor 52.

In this way, when the substrate W is held by the substrate holder 16, the back surface of the substrate W is covered with the heat conductor 38, and the outer peripheral portion of the substrate W is supported by the support frame 36 of the substrate stage 30 and the sealing material 48a. , 48b for sealing. For this reason,
Even if the substrate W held by the substrate holding unit 16 is dipped in the plating solution 12, the back surface and the outer peripheral portion of the substrate W do not come into contact with the plating solution, and therefore, this is not plated.

Moreover, the substrate W held by the substrate holding unit 16
By surrounding the periphery of the cylindrical body 44 with the cylindrical body 44 and providing the communication hole 50 at a predetermined position along the height direction of the cylindrical body 44, the substrate holding portion 16 is lowered while holding the substrate W. When
Until the liquid surface of the plating solution 12 held in the plating tank 14 reaches the communication hole 50, the plating solution 12 is kept in the cylindrical body 44.
Inside of the substrate W, that is, when it reaches the communication hole 50 without flowing into the plated surface (upper surface) of the substrate W, it flows into the inside of the tubular body 44 from the communication hole 50 to cover the substrate W. The plating surface is immersed in the plating solution.

At this time, the support frame 36 of the substrate stage 30 and the heat conductor 38 come into contact with the plating solution 12 in the plating tank 14 before the plating solution 12 flows into the cylindrical body 44 from the communication hole 50. Then, the heat of the plating solution 12 itself heats (preheats) the substrate W and the support frame 36 held by the substrate holding portion 16. Here, as the heat conductor 38, a thin-walled one is used, and the heat conductor 38 easily follows the irregularities on the back surface of the substrate W to increase the contact area and efficiently heat the substrate W. The substrate W can be heated more uniformly in a short time by using a fluid (plating solution) that conducts electricity and has a large heat capacity as a heat source.

When heating (preheating) the substrate W, if necessary, the substrate holding part 16 is moved to the preheating position shown in FIG. 2, that is, the lower surface of the substrate stage 30 is the plating solution 1 in the plating bath 14.
2 and stop the liquid surface of the plating solution 12 at a position located below the communication hole 50 provided in the cylindrical body 44. That is, if the substrate holding unit 16 is lowered to the plating position shown in FIG.
When the substrate W cannot be sufficiently heated, the substrate holding unit 16 is stopped at the preheating position, and the substrate W and the support frame 36 are preheated by the heat of the plating solution 12 itself until the temperature reaches a stable temperature. After the temperature is stabilized, the substrate holding part 16 is lowered to the plating position shown in FIG.

In the electroless plating apparatus of this embodiment, the plating solution 12 heated to a predetermined temperature, for example, 60 ° C. is introduced into the plating tank 14 and the overflow weir 24 is allowed to overwhelm. On the other hand, the substrate holder 16 is replaced with the plating tank 14
The substrate W is inserted into the substrate stage 30 with the substrate holder 32 being relatively raised with respect to the substrate stage 30, and the support frame 36.
Hold on top. Then, the substrate holder 32 is lowered, and the sealing materials 48a and 48b are brought into pressure contact with the peripheral edge of the substrate W held by the support frame 36 and the upper surface of the projection 40 of the support frame 36, respectively, and the outer peripheral portion and the back surface of the substrate W are removed. The substrate W is held by sealing.

While holding the substrate W, the substrate holding portion 16 is lowered. Then, the lower surface of the substrate stage 30 first comes into contact with the plating solution 12 in the plating bath 14, and the substrate W
And the support frame 36 is heated by the heat of the plating solution 12 itself (preheating).
To be done. At this time, if necessary, the substrate holding unit 16 is stopped at the preheating position shown in FIG.
Is preheated (heated) by the heat of the plating solution 12 itself to stabilize the temperature of the substrate W and the support frame 36, and then the substrate holding unit 1
6 is lowered to the plating position shown in FIG.

As a result, the substrate W and the support frame 36 of the substrate holder 32 are preheated to the plating temperature and immersed in the plating solution 12, so that the entire surface of the substrate is uniformly plated at the initial plating stage. It is possible to grow a plating film having a uniform film thickness while maintaining the above condition. At this time, for example, the substrate W may be rotated to make the hydrogen density and the dissolved oxygen concentration on the plated surface uniform.

After the plating process is completed, the substrate holder 16
And the plating solution remaining on the upper surface of the substrate W is removed by suction or the like. Then, the substrate holding unit 16 is conveyed to a cleaning position or the like, and while the substrate W is rotated, a cleaning liquid is ejected from a cleaning liquid nozzle (not shown) toward the plated surface of the substrate W to cool the plated surface. At the same time, the electroless plating reaction is stopped by diluting and washing. Then, the substrate holder 32 is raised relative to the substrate stage 30 to release the holding of the substrate W, and then the substrate after plating is conveyed to the next step by a robot hand or the like.

FIG. 4 shows an electroless plating apparatus according to another embodiment of the present invention. This electroless plating apparatus is obtained by adding the following configuration to the electroless plating apparatus shown in FIGS. 2 and 3. That is, this electroless plating apparatus is used in the plating tank 1
4 has a chamber 60 that hermetically surrounds the upper portion of the chamber 4. The chamber 60 is provided with an inert gas introduction hole 60a for introducing an inert gas such as N ₂ into the inside thereof.

Further, a building bath 61 is provided, and a plating solution supply pipe 20 extending from the building bath 61 to the plating tank 14 is provided with a pump 62 and a filter 63, and a plating solution discharge hole 28 of the plating tank 14 is provided. The building bath 61 is connected by a plating solution return pipe 64. Further, the building bath 61 is provided with a plating solution temperature adjuster 65 for controlling the temperature of the plating solution 12 therein, and is further connected with a plurality of plating solution concentration adjusting tanks 66 for adjusting the concentration of the plating solution. ing.

As a result, when the pump 62 is operated,
The plating solution 12 is circulated between the plating tank 14 and the building bath 61, and the concentration and temperature of each component of the plating solution are adjusted in the building bath 61. According to this example, by introducing an inert gas such as N ₂ gas into the chamber 60 during the plating process, it is possible to eliminate the influence of the dissolved oxygen concentration of the plating solution on the plating film. Further, the plating solution in which the concentration of each component and the solution temperature are adjusted can be sequentially introduced into the plating tank.

FIG. 5 shows the overall structure of a plating processing apparatus for performing a series of plating processing by the electroless plating apparatus 10. This plating apparatus includes a pair of electroless plating apparatuses 10, a load / unload unit 70, for example, a catalyst treatment for applying a Pd catalyst or a plating treatment such as an oxide film removal treatment for removing an oxide film attached to the exposed wiring surface. It has a plating pretreatment device 72 for performing treatment, a temporary placement part 74 capable of rough cleaning, and a post-cleaning device 76, and further transports the substrate W between the load / unload part 70, the post-cleaning device 76 and the temporary placement part 74. A second transfer device 78a that transfers the substrate W between the first transfer device 78a and the electroless plating device 10, the plating pretreatment device 72, and the temporary placement unit 74.
A transport device 78b is provided.

Next, a series of plating processing steps by the plating processing apparatus configured as described above will be described. First, the substrate W held by the loading / unloading unit 70 is taken out by the first transfer device 78 a and placed on the temporary placement unit 74.
The second transfer device 78b transfers this to the pre-plating processing device 72, where pre-plating such as a catalyst applying process using a catalyst such as a PdCl ₂ solution or an oxide film removing process for removing an oxide film attached to the exposed wiring surface. It is processed and then rinsed.

The second transfer device 78b further transfers the substrate W to the electroless plating device 10, where it performs an electroless plating process using a predetermined reducing agent and a predetermined plating solution. Next, the substrate after plating is taken out from the electroless plating device 10 by the second transfer device 78 b and is transferred to the temporary placement part 74. In the temporary placement section 74, the substrate is roughly cleaned. Then, the first transfer device 78a
Carries the substrate to the post-cleaning device 76, and the post-cleaning device 76 performs the final cleaning with a pencil sponge and the spin-drying to dry the load / unload unit 70.
Return to. The substrate is later transferred to a plating device or an oxide film forming device.

FIG. 6 shows the overall structure of a plating processing apparatus for performing a series of plating processing (cover plating processing) for forming the protective film 9 shown in FIG. This plating apparatus has a loading / unloading section 80, a pretreatment section 82, a Pd adhering section 84, a plating pretreatment section 86, an electroless plating apparatus 10 and a cleaning / drying treatment section 88, and a transport path 90. A carrier device 92 is provided which can travel along the substrate and transfers the substrate between them.

Next, a series of plating process (capping process) performed by the plating apparatus configured as described above will be described. First, the substrate W held by the loading / unloading unit 80 is taken out by the transfer device 92, and the pretreatment unit 8
Then, the substrate is subjected to a pretreatment for cleaning the surface of the substrate again, for example. Then, Pd is adhered to the surface of the copper layer 7 (see FIG. 1) by the Pd adhering portion 84 to activate the exposed surface of the copper layer 7, and thereafter, pre-plating treatment such as neutralization is performed by the pre-plating treatment portion 86. Apply processing. Next, it is conveyed to the electroless plating apparatus 10, and here, on the surface of the activated copper layer 7,
For example, selective electroless plating with Co-WP is performed, thereby protecting the exposed surface of the copper layer 7 with a Co-WP film (protective film) 9 as shown in FIG. . Examples of the electroless plating solution include a salt of cobalt and a salt of tungsten, a reducing agent, a complexing agent, a pH buffering agent, and p.
The thing which added the H regulator is mentioned.

The surface exposed after polishing is subjected to, for example, electroless Ni-B plating, and a protective film (plating film) 9 made of a Ni-B alloy film is selectively formed on the exposed surface of the wiring 8. The wiring 8 may be formed to protect the wiring 8.
The thickness of the protective film 9 is 0.1 to 500 nm, preferably 1 to 200 nm, more preferably 10 to 100 n.
It is about m.

The electroless Ni-B plating solution for forming the protective film 9 contains, for example, nickel ions, a complexing agent for nickel ions, an alkylamine borane as a reducing agent for nickel ions, or a borohydride compound, What adjusted pH to 5-12 using TMAH (tetramethylammonium hydroxide) for pH adjustment is used.
Next, the substrate W after the lid plating processing is transported to the cleaning / drying processing unit 88 to be subjected to cleaning / drying processing, and the substrate W after cleaning / drying is loaded / unloaded by the transportation device 92.
Return to the cassette.

In this example, as the lid plating treatment,
Before performing the Co-WP electroless plating treatment, the exposed surface of the copper layer 7 activated by depositing Pd was Co.
An example in which the -WP film is selectively coated is shown, but the present invention is not limited to this. Further, each of the above examples shows an example applied to an electroless plating apparatus, but it goes without saying that it can also be applied to an electrolytic plating apparatus in which a plating current is caused to flow between an anode and a cathode during plating. .

[0048]

As described above, according to the present invention,
By adopting the so-called face-up method and by plating the material to be processed by immersing it in a plating solution with the back surface and outer periphery of the material being sealed, hydrogen generated during plating can be easily removed from the surface to be plated. It is possible to separate and perform stable plating. Moreover, when the material to be treated is immersed in the plating solution, by heating the material to be treated with the heat of the plating solution, the material to be treated can be maintained at a uniform plating temperature over the entire surface from the initial stage of plating. It is possible to grow a plating film having a uniform thickness. Also, by placing the plating tank in an inert gas atmosphere, it is possible to eliminate the influence of the dissolved oxygen concentration of the plating solution on the plating film.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of forming a copper wiring by copper plating in the order of steps.

FIG. 2 is a cross-sectional view showing a state when the substrate holding portion of the electroless plating apparatus according to the embodiment of the present invention is in a preheating position.

FIG. 3 is a cross-sectional view showing a state when the substrate holding portion of the electroless plating apparatus according to the embodiment of the present invention is at the plating position.

FIG. 4 is an overall view showing an electroless plating apparatus according to another embodiment of the present invention.

5 is a plan layout view showing a plating apparatus including the electroless plating apparatus shown in FIGS. 2 and 3. FIG.

FIG. 6 is a plan layout view showing another plating apparatus including the electroless plating apparatus shown in FIGS. 2 and 3.

[Explanation of symbols]

6 Copper seed layer 7 Copper layer 8 wiring 9 Protective film 10 Electroless plating equipment 12 Plating solution 14 Plating tank 16 Substrate holder 22 heater 24 overflow weir 30 substrate stage 32 substrate holder 34 housing 36 Support frame 38 heat conductor 40 Projection 42 through hole 44 Cylindrical body 46 Claw 48a, 48b Seal material 50 communication holes 54 Support 60 chambers 60a Inert gas introduction hole 61 bathtub 64 plating solution return pipe 65 Plating solution temperature controller 66 Tank for plating solution concentration adjustment 70,80 Load / unload section 72 Pretreatment device 74 Temporary storage 76 Post-cleaning device 82 Pre-processing unit 84 Pd adhesion part 86 Plating pretreatment section 88 Washing / drying unit

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Claims (8)

[Claims] 1. A plating tank which opens upward and holds a heated plating solution; and a plating tank which is arranged at a position covering an upper end opening of the plating tank and seals a back surface and an outer peripheral portion of a material to be plated. A plating apparatus comprising: a holding unit that exposes and holds the material to be processed facing upward; and a unit that immerses the material to be processed held by the holding unit in a plating solution in the plating tank. 2. The holding unit has a stage and a holder that are relatively movable up and down, the back surface of the material to be processed is covered with the stage, and the peripheral portion of the plated surface of the material to be processed is the holder. The plating apparatus according to claim 1, wherein the target material is held by sealing with a sealing material provided. 3. The stage includes a ring-shaped support frame,
The plating apparatus according to claim 2, further comprising a thin-film heat conductor stretched inside the support frame. 4. The holding unit is vertically movable with respect to the plating bath, and the thermal conductor is brought into contact with a plating solution in the plating bath to preheat the material to be processed held by the holding unit. The plating apparatus according to claim 3, wherein the preheating position and the processing target material are immersed in the plating solution in the plating tank and stopped at a plating position where plating is performed. 5. The plating bath is configured to introduce a plating liquid into the plating bath from the bottom of the plating bath and to overflow the plating liquid from the top of the plating bath. The plating apparatus according to any one of 1. 6. A plating bath that opens upward and holds a heated plating solution; and a plating bath that is disposed at a position that covers an upper end opening of the plating bath and that seals the peripheral edge of the surface to be plated to hold the material to be treated. A holding part, a means for bringing the material to be processed held by the holding part into contact with the plating solution in the plating tank, a chamber that hermetically surrounds the upper part of the plating tank, and an inert gas in the chamber. A plating apparatus comprising: an inert gas introducing means for introducing. 7. The processing target material is held by a holding part, the processing target material held by the holding part is heated by a plating solution held in a plating tank, and the heated processing target material is plated in the plating tank. A plating method characterized by immersing in and plating. 8. The material to be treated is placed and held upward on the upper surface of the heat conductor, and the heat conductor is heated by contacting the heat conductor with a plating solution in a plating tank. 7. The plating method according to 7.