JP2007332445A - Electroless plating method and electroless plating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroless plating method which can form a protective film with a uniform thickness on the surface of wires by completely removing an anticorrosive agent and/or a metal complex from the surface of a substrate, prior to catalyst-imparting treatment and/or an electroless plating step. <P>SOLUTION: The electroless plating method comprises the steps of: preparing a substrate having embedded wiring formed in the inner part; making a washing member contact with the surface or both sides of the substrate in a wet state; making the washing member supply cleaning fluid onto the surface or both sides of the substrate while relatively moving them to pre-wash the substrate; making the catalyst-imparting liquid contact with the surface of the pre-washed substrate to impart a catalyst onto the surface of the wiring; and then making an electroless plating solution contact with the surface of the substrate to form the protective film selectively on the surface of the wiring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electroless plating method and an electroless plating apparatus, and more particularly to an exposed surface of an embedded wiring configured by embedding copper or the like as a wiring material (conductor) in a wiring recess provided on the surface of a substrate such as a semiconductor wafer. The present invention relates to an electroless plating method and an electroless plating apparatus used to selectively form a protective film for protecting an exposed surface of the wiring. The electroless plating method and electroless plating apparatus of the present invention are also applied to, for example, a magnetic film manufacturing process of MRAM and a flat panel manufacturing process.

  As a wiring formation process of a semiconductor substrate, a process (so-called damascene process) in which a metal (conductor) is buried in a wiring recess such as a trench or a via hole is being used. This is a process in which aluminum, in recent years copper or silver, is buried in trenches or via holes previously formed in the interlayer insulating film by plating, and then the excess metal is removed by chemical mechanical polishing (CMP) and planarized. Technology.

In recent years, with the acceleration of high speed and miniaturization of semiconductor devices, the damascene process (wiring embedding) of copper wiring / low dielectric constant interlayer insulating film material (Low-K) instead of aluminum has become more and more important. . Furthermore, it is indispensable to increase the electromigration (EM) resistance of the copper wiring in order to increase the reliability of the device. As one of the countermeasures, a remarkable effect has been demonstrated in order to improve the resistance of EM by selectively forming a cobalt (Co) alloy film on the copper wiring. In addition, if the formed cobalt film can sufficiently play a role of preventing diffusion of copper or oxygen (O ₂ ), it is possible to omit a cap layer of an insulating material having a high dielectric constant used in a conventional process. It can be expected to further reduce the effective dielectric constant between the wiring layers. Regarding the method of film formation, the electroless plating method has a unique property that can be selectively formed only on the metal with respect to the surface where the metal and the insulating material are mixed, so a cobalt alloy thin film is formed on the copper wiring. It is considered to be the most suitable method. From the above, the technology for forming a cobalt alloy film by electroless plating (electroless cap plating) is considered to be the most promising new process in the construction of next-generation highly reliable copper wiring.

  FIG. 24A shows a conventional copper damascene wiring structure. Usually, the adhesion between the copper wiring 513 and the adjacent insulating cap layer 514 made of, for example, SiN, SiC, or SiCN is lower than that of metals, and therefore the movement of atoms at the interface is caused in the wiring 513 or the wiring 513. And the barrier metal layer 515 surrounding it tend to be more active. When the current density flowing in the wiring 513 increases with the miniaturization of the wiring 513, it is most likely to become the path of atom movement along the boundary between the copper wiring 513 and the insulating cap layer 514, and the interface is defective due to EM (void of voids). The probability of becoming a formation) is high.

As one countermeasure, it has been proposed to introduce a new alloy thin film 516 between the copper wiring 513 and the insulating cap layer 514 as shown in FIG. This alloy thin film 516 is called a cap metal. The cap metal 516 has excellent adhesiveness with each of the copper wiring 513 and the insulating cap layer 514, and the introduction of the cap metal 516 greatly improves the EM resistance of the copper wiring 513. Further, if the cap metal 516 has sufficient resistance to copper and oxygen (O ₂ ) diffusion, as shown in FIG. 24C, the cap metal 516 is protected instead of the insulating cap layer 514 currently used. The film 517 can be used. In general, since the insulating cap layer 514 has a high dielectric constant, it is possible to reduce the charge capacity (C) between the wiring layers by not stacking the insulating cap layer 514, and to increase the signal transmission speed by suppressing the RC delay of the circuit. Contribute to. Furthermore, noise can be reduced and heat generation can be reduced.

  In general, in order to selectively form the protective film 517 on the surface of the wiring 513, first, as shown in FIG. 25A, the surface of the wiring 513 in the insulating film 518 is exposed by CMP. At this time, a copper oxide film 519a is formed on the surface of the wiring 513, and a residue 519b may remain on the insulating film 518 in some cases. Therefore, as shown in FIG. 25B, the surface is cleaned to remove the copper oxide film 519a and the residue 519b, and then, as shown in FIG. The catalyst (nucleus) 521 is provided. Then, for example, electroless CoWP plating is performed on the surface, and a protective film 517 made of a CoWP alloy is selectively formed on the surface of the wiring 513 as shown in FIG. At this time, a metal residue 523 may remain on the surface of the protective film 517 or the insulating film 518.

Therefore, as shown in FIG. 25E, cleaning after plating is performed to remove the metal residue 523 remaining on the surface of the protective film 517 and the insulating film 518, and then the surface is cleaned with pure water and dried. Thus, as shown in FIG. 25F, a protective film 517 having a stabilized surface is obtained.
Depending on the characteristics and purpose of the object to be plated, special processing steps may be added or deleted during certain steps. Hereinafter, some basic processing steps will be described.

  Unlike the electroplating used for copper damascene wiring, electroless plating does not use external electron supply, but reduces the metal ions by simply immersing the plating object in a plating solution containing metal ions. It is a method of depositing as a film. In order to reduce metal ions, a reducing agent component for releasing electrons is essential in addition to metal ions in the plating solution. A basic chemical reaction formula for depositing a CoWP (cobalt, tungsten, phosphorus) alloy film in a plating solution system using hypophosphite as a reducing agent is shown below.

Oxidation reaction of hypophosphite ion H ₂ PO ₂ ⁻ + OH → H ₂ PO ₃ ⁻ + H + e ⁻
Cobalt ion reduction reaction Co ₂ + 2H ₂ PO ₂ ⁻ + OH ⁻ → Co + H ₂ PO ₃ ⁻ + H ₂
Phosphorus ion reduction reaction H ₂ PO ₂ ⁻ + e ⁻ → P ↓ + 2OH ⁻
・ Reduction reaction of tungsten ions WO ₂ ²⁺ + 6H ₂ PO ₂ ⁻ + 4H ₂ O → W + 6H ₂ PO ₃ ⁻ + 3H ₂ + 2H ⁺
・ Hydrogen generation reaction H ⁺ + e ⁻ + H → H ₂ ↑

As described above, electrons are released by the oxidation reaction of the hypophosphite of the reducing agent, and cobalt, phosphorus, and tungsten ions acquire the electrons on the reaction surface and perform a eutectoid reaction to form an alloy film. Along with the eutectoid reaction, a reduction reaction of hydrogen usually proceeds.
A typical reducing agent in the plating solution is organic dimethylamine borane (DMAB) in addition to the hypophosphite described above. Plating solutions that use DMAB as a reducing agent behave differently than hypophosphite plating solutions.

In electroless plating, the initial coating surface must have sufficient catalytic activity for the oxidizing reaction of the reducing agent in order to initiate deposition. Since copper exhibits a very low catalytic activity for the hypophosphite anodic oxidation reaction, in principle, a plating reaction cannot occur. Therefore, it is common to use Pd having high catalytic activity in order to deposit a cobalt alloy on the copper surface. That is, before starting the plating reaction, a catalyst treatment with a pretreatment liquid containing Pd ions on the coating surface is required. The catalyst treatment is a substitution reaction, and the reaction formula is as follows.
Cu → Cu ²⁺ + e ⁻
Pd ²⁺ + e ⁻ → Pd

Normally, Pd does not cause a substitution reaction on the surface of a low-K material such as SiO ₂ or SiOC, which is an insulating material, and therefore, an electroless plating reaction occurs only on a copper wiring, so-called selective film formation process. become.

  As described above, the electroless plating using the Pd catalyst is a selective film formation in principle, but in fact, as shown in FIG. 25A, on the (interlayer) insulating film 518 after the CMP process. In some cases, a slurry residue 519b remains, a copper oxide film 519a is formed on the wiring 513, and impurities such as a watermark remain. When a Pd substitution reaction or a plating reaction occurs on the impurities, abnormal precipitates between the wirings cause not only wiring leakage but also an increase in surface defects. Therefore, performing an appropriate surface cleaning process before or after the plating process is an indispensable means for improving the process performance.

In copper wiring, the surface of the wiring is exposed to the outside after planarization, and when forming a buried wiring on this, for example, surface oxidation during SiO ₂ formation in the interlayer insulating film forming process in the next step In addition, there is a concern about surface contamination due to etchant of the wiring exposed at the bottom of the via hole, resist peeling, or the like during SiO ₂ etching for forming the via hole.

  For this reason, as described above, the bonding with a wiring material such as copper or silver is strong and the specific resistance (ρ) is low, for example, Co (cobalt) or Co alloy layer obtained by electroless plating, Ni (nickel) It has been proposed to protect the wiring by selectively covering the surface of the wiring with a Ni alloy layer.

26A to 26D show an example of forming a copper wiring in a semiconductor device in the order of steps. First, as shown in FIG. 26A, an insulating film (interlayer insulating film) such as an oxide film made of SiO ₂ or a Low-K material film is formed on the conductive layer 1a on the semiconductor substrate 1 on which the semiconductor element is formed. ) 2 is deposited, and via holes 3 and wiring grooves 4 as fine concave portions for wiring are formed in the insulating film 2 by, for example, lithography / etching technique, and a barrier layer 5 made of TaN or the like is formed thereon, and A seed layer 6 as a power feeding layer for electrolytic plating is formed thereon by sputtering or the like.

  Then, as shown in FIG. 26 (b), copper is plated on the surface of the substrate W to fill the via holes 3 and the wiring grooves 4 of the substrate W with copper, and the copper layer 7 is formed on the insulating film 2. Deposit. Thereafter, the barrier layer 5, the seed layer 6 and the copper layer 7 on the insulating film 2 are removed by chemical mechanical polishing (CMP) or the like, and the surface of the copper layer 7 filled in the via hole 3 and the wiring groove 4 The surface of the insulating film 2 is substantially flush with the surface. Thereby, as shown in FIG. 26C, a wiring (copper wiring) 8 composed of the seed layer 6 and the copper layer 7 is formed inside the insulating film 2.

  Next, as shown in FIG. 26 (d), the surface of the substrate W is subjected to electroless plating, and a protective film 9 made of Co alloy, Ni alloy or the like is selectively formed on the exposed surface of the wiring 8, Thus, the surface of the wiring 8 is covered and protected by the protective film 9.

A process of selectively forming a protective film (lid material) 9 made of, for example, a CoWP alloy film on the surface of the (copper) wiring 8 by general electroless plating will be described with reference to FIG. First, a substrate W (see FIG. 26C) such as a semiconductor wafer in which the wiring 8 is exposed by performing a planarization process such as CMP is prepared. The substrate W is immersed in, for example, room temperature dilute sulfuric acid or dilute hydrochloric acid for about 1 minute to remove impurities such as a metal oxide film and a CMP residue such as copper on the surface of the insulating film 2, thereby pre-cleaning the substrate W I do. Then, after cleaning (rinsing) the surface of the substrate W with pure water or the like, for example, the substrate W is immersed in a PdCl ₂ / HCl or PdSO ₄ / H ₂ SO ₄ mixed solution at room temperature for about 1 minute, thereby Pd as a catalyst is attached to the surface of 8 to activate the exposed surface of the wiring 8.

  Next, after cleaning (rinsing) the surface of the substrate W with pure water or the like, for example, the substrate W is immersed in a CoWP plating solution having a liquid temperature of 80 ° C. for about 120 seconds to activate the surface of the activated wiring 8. Selective electroless plating is performed, and then the surface of the substrate W is washed (rinsed) with pure water or the like. As a result, as shown in FIG. 26D, the protective film 9 made of a CoWP alloy film is selectively formed on the exposed surface of the wiring 8 to protect the wiring 8.

  For wiring (copper wiring) formed by applying CMP (Chemical Mechanical Polishing) to the surface of the substrate and planarizing the surface, anticorrosion such as BTA (benzotriazole) is used until it is processed in the next film formation process. It is widely used to protect the wiring surface from corrosion with an agent. A portion of this anticorrosive agent binds to the wiring metal to form a metal complex, thereby preventing the wiring from corrosion. In this case, it is necessary to completely remove the anticorrosive and / or the metal complex from the surface of the substrate immediately before the next film forming step. When the next film-forming process forms a barrier layer of an insulating material on the surface of the substrate by CVD, the anticorrosive agent and / or the metal complex on the surface of the substrate is removed by dry processing such as plasma cleaning or UV irradiation performed as a pretreatment. Can be removed.

  However, in the case of electroless plating in which the next film formation process selectively forms a protective film on the exposed surface of the wiring, the processing liquid is sprayed toward the surface of the substrate or the substrate is immersed in the processing liquid. In the pre-cleaning (pretreatment) for cleaning the substrate, the adhesion of the anticorrosive agent and / or the metal complex to the wiring surface is generally strong, and thus the anticorrosive agent and / or the metal complex on the wiring surface may not be sufficiently removed. As a result, an anticorrosive and / or a metal complex remains on a part of the cleaned wiring surface, which hinders the catalyst application treatment and / or the electroless plating treatment in the next step, and causes the wiring surface to be removed by electroless plating. The film thickness of the protective film formed on the film becomes non-uniform.

  In addition, when performing pre-cleaning (pre-processing) of the substrate by spraying the processing liquid toward the surface of the substrate, it is generally performed to spray the processing liquid from a large number of spray nozzles in order to effectively clean the entire surface of the substrate. It has been broken. For this reason, the amount of processing liquid (chemical solution) used in one processing increases, which is disadvantageous in terms of cost. On the other hand, when the substrate is immersed in the processing solution to perform pre-cleaning (pre-processing) of the substrate, the processing solution is generally reused while being circulated, so that impurities mixed in the processing solution are regenerated on the surface of the substrate. Adhesion may reduce cleaning efficiency. In addition, the time required for the cleaning process is generally longer.

  The present invention has been made in view of the above circumstances, and prior to the catalyst application treatment and / or electroless plating, the anticorrosive agent and / or metal complex is completely removed from the surface of the substrate so that the surface of the wiring is uniform. An object of the present invention is to provide an electroless plating method and an electroless plating apparatus capable of forming a protective film having a thickness.

  According to the first aspect of the present invention, a substrate having an embedded wiring formed therein is prepared, the cleaning member is brought into contact with the surface or both surfaces of the wet substrate, and both the surfaces are moved relative to each other while moving the two relative to each other. In the electroless plating method, the pretreatment liquid is supplied to the substrate, and then the substrate surface is brought into contact with the electroless plating liquid to selectively form a protective film on the surface of the wiring. is there.

  According to the present invention, a protective film is directly formed on the wiring surface without applying a catalyst, or the substrate surface is washed and the catalyst is applied to the wiring surface simultaneously using one pretreatment liquid. When a protective film is to be formed later on the wiring surface, the substrate is subjected to pretreatment that combines the chemical action by the pretreatment liquid and the mechanical action by the cleaning member (scrub cleaning) prior to film formation by electroless plating. The anticorrosive and / or metal complex remaining on the surface of the metal can be completely removed. In addition, pretreatment over the entire surface of the substrate can be performed by bringing the cleaning member into contact with the surface of the substrate and relatively moving both of them.

The invention according to claim 2 is characterized in that the surface of the substrate after the pretreatment is rinsed with pure water, and the surface of the substrate is brought into contact with an electroless plating solution before the surface of the substrate is completely dried. The electroless plating method according to claim 1.
As a result, it is possible to suppress the formation of an oxide film on the surface of the wiring or the formation of a watermark between the pretreatment and the start of electroless plating, and to prevent defects in the protective film (plating film). Its purpose is to prevent it from occurring.

  According to a third aspect of the present invention, a substrate having an embedded wiring formed therein is prepared, the cleaning member is brought into contact with the surface or both surfaces of the wet substrate, and both the surfaces are moved while relatively moving both. The substrate is pre-cleaned by supplying a cleaning solution to the substrate, and the surface of the substrate after the pre-cleaning is brought into contact with the catalyst applying solution to apply the catalyst to the surface of the wiring. Then, the electroless plating method is characterized in that a protective film is selectively formed on the surface of the wiring.

  According to this invention, when the protective film is formed after applying the catalyst to the wiring surface, the chemical action by the cleaning liquid and the mechanical action by the cleaning member are combined prior to the process of applying the catalyst to the wiring surface. The anti-corrosion agent and / or metal complex remaining on the surface of the substrate by the pre-cleaning is completely removed, the catalyst is uniformly applied to the wiring surface, and the protective film is in a state where there is no anti-corrosion agent and / or metal complex on the wiring surface. Can be formed.

The invention according to claim 4 is characterized in that the surface of the substrate after the pre-cleaning is rinsed with pure water, and the surface of the substrate is brought into contact with the catalyst applying liquid before the surface of the substrate is completely dried. Item 4. The electroless plating method according to Item 3.
This prevents the formation of an oxide film on the wiring surface or the formation of a watermark between the pre-cleaning process and the start of the catalyst application process, thereby uniformly applying the catalyst to the wiring surface. Then, it is possible to prevent a defect from occurring in the protective film (plating film) formed by subsequent electroless plating.

  In the invention according to claim 5, the cleaning member is brought into contact with the surface or both surfaces of the wet substrate, and the pretreatment is performed by supplying the pretreatment liquid to the surface or both surfaces of the substrate while relatively moving both of them. An electroless plating apparatus comprising: a pretreatment unit; and an electroless plating unit that selectively forms a protective film on a surface of a wiring by bringing a surface of a substrate into contact with an electroless plating solution.

  According to the sixth aspect of the present invention, the cleaning member is brought into contact with the surface or both surfaces of the wet substrate, and the substrate is pre-cleaned by supplying a cleaning liquid to the surface or both surfaces of the substrate while relatively moving both of them. A pre-cleaning unit, a catalyst-applying unit that contacts the surface of the substrate after pre-cleaning with the catalyst-applying solution, and a catalyst on the surface of the wiring, and a surface of the substrate that contacts the electroless plating solution to protect the surface of the wiring An electroless plating apparatus having an electroless plating unit that selectively forms a film.

The invention described in claim 7 further includes a cleaning unit for cleaning the substrate by immersing the substrate in the cleaning liquid or spraying the cleaning liquid toward the substrate. Electrolytic plating apparatus.
Thereby, the multi-step process which combined the pre-processing unit and the washing | cleaning unit or the pre-cleaning unit and the washing | cleaning unit can be performed, and the cleaning effect of a board | substrate can be improved more.

The invention according to claim 8 is the electroless plating apparatus according to any one of claims 5 to 7, wherein the cleaning member is made of polyvinyl alcohol or a fluororesin material having a porous continuous pore structure. .
Polyvinyl alcohol (PVA) having a porous continuous pore structure is excellent in hygroscopicity and chemical resistance and is widely used as a roll sponge, and is used as a cleaning member for cleaning the surface by contacting the surface of the substrate. Thus, the residue remaining on the surface of the substrate can be easily removed without damaging the surface of the substrate.

A ninth aspect of the present invention is the electroless plating apparatus according to any one of the fifth to eighth aspects, wherein the cleaning member is a roll brush having a rotation shaft at the center.
Thus, the cleaning efficiency of the surface of the substrate can be improved by cleaning the surface of the substrate by rotating the roll brush in contact with the surface of the substrate.

  According to the present invention, the anti-corrosion agent and / or the metal remaining on the surface of the substrate including the surface of the wiring by performing the pre-treatment etc. by combining the chemical action by the chemical solution and the mechanical action by the cleaning member (scrub cleaning). A protective film having a uniform film thickness can be formed on the wiring surface by effectively removing the complex, and then performing a catalyst application treatment and / or electroless plating. In addition, uniform pretreatment and precleaning over the entire surface of the substrate can be performed in a short time of, for example, about 5 to 60 seconds while suppressing the amount of the chemical used to 1 liter or less, for example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following example, as shown in FIG. 26 (d), the exposed surface of the wiring 8 is selectively covered with a protective film (covering material) 9 made of a CoWP alloy or the like, and the wiring 8 is covered with the protective film 9. An example of protection is shown.

  FIG. 1 is a plan layout view of an electroless plating apparatus according to an embodiment of the present invention. As shown in FIG. 1, the electroless plating apparatus is provided with a load / unload unit 11 for mounting and storing a substrate cassette containing a substrate W such as a semiconductor wafer having a wiring 8 formed on the surface thereof. Then, inside the rectangular apparatus frame 12 provided with the exhaust system, a pre-cleaning unit 14 for pre-cleaning the surface of the substrate, and a catalyst application liquid is brought into contact with the surface of the substrate after pre-cleaning, so that the surface of the wiring 8 For example, a catalyst applying unit 15 for applying a catalyst such as Pd is disposed.

  Inside the apparatus frame 12, the selectivity of the two electroless plating units 16 for performing electroless plating on the surface of the substrate and the protective film (alloy film) 9 formed on the surface of the wiring 8 by electroless plating is improved. Therefore, a post-cleaning unit 18 for performing post-cleaning (post-processing) of the substrate, a drying unit 20 for drying the post-cleaned substrate, and a temporary table 22 are disposed. Further, in the apparatus frame 12, a first substrate transfer robot 24 for transferring the substrate W between the substrate cassette mounted on the load / unload unit 11 and the temporary table 22, the temporary table 22 and each unit 14. , 15, 16, 18, and 20 are disposed so as to be able to travel, respectively.

  Next, details of each unit provided in the electroless plating apparatus shown in FIG. 1 will be described below. The pre-cleaning unit 14 is a unit that removes the anticorrosive agent and / or metal complex remaining on the surface of the substrate W including the surface of the wiring prior to the catalyst application treatment. This is a unit that removes particles and unwanted materials on the substrate surface after electroless plating. In this example, the pre-cleaning unit 14 and the post-cleaning unit 18 have the same configuration except for the processing liquid to be used. Therefore, only the pre-cleaning unit 14 will be described here, and the description of the post-cleaning unit 18 will be given. Omitted.

  As shown in FIGS. 2 and 3, the pre-cleaning unit 14 supplies a cleaning liquid to a plurality of rollers 30 that sandwich the outer periphery of the substrate W and holds the substrate W, and the surface of the substrate W held by the roller 30. There are provided a cleaning liquid nozzle 32 and a pure water nozzle 34 for supplying pure water, a cleaning liquid nozzle 36 for supplying a cleaning liquid to the back surface of the substrate W held by the roller 30, and a pure water nozzle 38 for supplying pure water. Yes.

A cylindrical cleaning member 42 having a rotating shaft 40 at the center and positioned on the front surface side of the substrate W held by the roller 30 is positioned at the back surface side of the substrate and having a rotating shaft 44 at the center. The members 46 are arranged so as to move in the vertical direction and come into contact with the substrate W, respectively. Both the cleaning members 42 and 46 are constituted by, for example, a roll brush made of a roll sponge made of polyvinyl alcohol (PVA) having a porous continuous pore structure. As described above, the surface of the substrate is cleaned by forming the cleaning members (roll brushes) 42 and 46 with a roll sponge made of polyvinyl alcohol (PVA) having a porous continuous pore structure excellent in hygroscopicity and chemical resistance. By bringing the members 42 and 46 into contact with each other and relatively moving them, the residue remaining on the surface of the substrate can be easily removed without damaging the surface of the substrate. In addition, the cleaning members 42 and 46 are roll-shaped brushes having the rotation shafts 40 and 44 in the center, and the surface of the substrate is cleaned by rotating the roll-shaped brush while contacting the surface of the substrate to clean the surface of the substrate. Cleaning efficiency can be improved.
The cleaning member may be a fluororesin material.

  According to the pre-cleaning unit 14, the substrate W is held by the plurality of rollers 30 with the surface (surface to be processed) facing upward, and the substrate W is rotated at a predetermined rotation speed, for example, 110 rpm via the rollers 30. Meanwhile, pure water is dropped from the pure water nozzle 34 onto the surface (upper surface) of the substrate W to wet the entire surface of the substrate W with pure water. Next, the cleaning member (roll brush) 42 disposed above the substrate W is lowered while being rotated at a predetermined rotation speed, for example, 100 rpm, and brought into contact with the surface of the substrate W. Then, at the same time as the cleaning member (roll brush) 42 contacts the surface of the substrate W, the cleaning liquid is supplied to the surface of the substrate W from the cleaning liquid nozzle 32 disposed above the substrate W. Thus, when a protective film is formed after the catalyst is applied to the wiring surface, the chemical action by the cleaning liquid and the mechanical action (scrub cleaning) by the cleaning member 42 are performed prior to the process of applying the catalyst to the wiring surface. The anticorrosive agent and / or metal complex remaining on the surface of the substrate W by the combined pre-cleaning can be completely removed.

  In parallel with the pre-cleaning of the front surface (upper surface) of the substrate, pre-cleaning of the back surface (lower surface) of the substrate is performed as necessary. That is, pure water is supplied from the pure water nozzle 38 to the back surface (lower surface) of the substrate W, and the cleaning member (roll brush) 46 disposed below the substrate W is rotated at a predetermined rotation speed, for example, 100 rpm. Raised and brought into contact with the back surface of the substrate W. Then, at the same time that the cleaning member (roll brush) 46 contacts the back surface of the substrate W, the cleaning liquid is supplied to the surface of the substrate W from the cleaning liquid nozzle 36 disposed below the substrate W, whereby the cleaning liquid is chemically treated with the cleaning liquid. The back surface of the substrate W is cleaned by pre-cleaning that combines the action and the mechanical action of the cleaning member 46.

Then, after cleaning the surface of the substrate for a predetermined time, for example, 30 seconds, the cleaning member 42 is raised and separated from the surface of the substrate W, the supply of the cleaning liquid from the cleaning liquid nozzle 32 is stopped, and then the pure water nozzle 34 Pure water is supplied to the surface of the substrate W to rinse the surface of the substrate W with pure water.
Similarly, after the back surface of the substrate W is cleaned for a predetermined time, the cleaning member 46 is lowered and separated from the back surface of the substrate W, and the supply of the cleaning liquid from the cleaning liquid nozzle 36 is stopped. Pure water is supplied from the water nozzle 38 to the back surface of the substrate W, and the back surface of the substrate W is rinsed with pure water.

Note that only the pure water nozzle 38 may be disposed on the back side of the substrate so that only the pure water is rinsed on the back side of the substrate, or when the cleaning liquid does not wrap around the back side of the substrate. The rinsing with pure water on the back surface of the substrate may be omitted.
In this example, the pre-cleaning unit 14 is provided with a sponge 48 that rotates while contacting the edge (outer peripheral portion) of the substrate W, and the sponge 48 is applied to the edge of the substrate W to scrub and clean it. It has become.

  4 to 6, the catalyst applying unit 15 includes a fixed frame 52 attached to the upper portion of the frame 50 and a moving frame 54 that moves up and down relatively with respect to the fixed frame 52. As shown in FIG. 7, a processing head 60 having a bottomed cylindrical housing portion 56 opened downward and a substrate holder 58 is suspended and supported by the moving frame 54. In other words, the head rotating servo motor 62 is attached to the moving frame 54, and the housing portion 56 of the processing head 60 is connected to the lower end of the output shaft (hollow shaft) 64 that extends below the servo motor 62.

  As shown in FIG. 7, a vertical shaft 68 that rotates integrally with the output shaft 64 is inserted into the output shaft 64 via a spline 66, and a ball joint 70 is attached to the lower end of the vertical shaft 68. The substrate holder 58 of the processing head 60 is connected through the via. The substrate holder 58 is located inside the housing portion 56. The upper end of the vertical shaft 68 is connected to a fixed ring elevating cylinder 74 fixed to the moving frame 54 via a bearing 72 and a bracket. As a result, the vertical shaft 68 moves up and down independently of the output shaft 64 in accordance with the operation of the lifting cylinder 74.

  As shown in FIGS. 4 to 6, the fixed frame 52 is attached with a linear guide 76 that extends in the vertical direction and serves as a guide for raising and lowering the moving frame 54, and the head raising and lowering cylinder (not shown) is operated. Thus, the moving frame 54 moves up and down using the linear guide 76 as a guide.

  As shown in FIG. 7, the peripheral wall of the housing portion 56 of the processing head 60 is provided with a substrate insertion window 56a for inserting the substrate W therein. Further, as shown in FIGS. 8 and 9, a peripheral portion is sandwiched between a main frame 80 made of, for example, polyether ether ketone and a guide frame 82, at the lower portion of the housing portion 56 of the processing head 60. 84 is arranged. The seal ring 84 abuts on the peripheral edge of the lower surface of the substrate W and seals it.

  A substrate fixing ring 86 is fixed to the periphery of the lower surface of the substrate holder 58, and a cylindrical pusher 90 is attached to the substrate fixing ring through the elastic force of a spring 88 disposed inside the substrate fixing ring 86 of the substrate holder 58. Projects downward from the lower surface of 86. Further, a bendable cylindrical bellows plate 92 made of, for example, Teflon (registered trademark) is hermetically sealed between the upper surface of the substrate holder 58 and the upper wall portion of the housing portion 56. Yes. Further, the substrate holder 58 is provided with a covering plate 94 that covers the upper surface of the substrate held by the substrate holder 58.

  Accordingly, the substrate W is inserted into the housing portion 56 from the substrate insertion window 56a with the substrate holder 58 raised. Then, the substrate W is guided by a tapered surface 82 a provided on the inner peripheral surface of the guide frame 82, positioned, and placed at a predetermined position on the upper surface of the seal ring 84. In this state, the substrate holder 58 is lowered, and the pusher 90 of the substrate fixing ring 86 is brought into contact with the upper surface of the substrate W. Then, by further lowering the substrate holder 58, the substrate W is pressed downward by the elastic force of the spring 88, and is thereby brought into pressure contact with the peripheral portion of the surface (lower surface) of the substrate W by the seal ring 84, While sealing, the substrate W is sandwiched and held between the housing portion 56 and the substrate holder 58.

  In this way, when the head rotating servomotor 62 is driven while the substrate W is held by the substrate holder 58, the output shaft 64 and the vertical shaft 68 inserted into the output shaft 64 are connected via the spline 66. The housing portion 56 and the substrate holder 58 are also rotated integrally.

  A processing tank 100 (see FIG. 10) having an outer tank 100a and an inner tank 100b, which is located below the processing head 60 and opens upward having an inner diameter slightly larger than the outer diameter of the processing head 60, is provided. Yes. A pair of leg portions 104 attached to the lid 102 is rotatably supported on the outer peripheral portion of the inner tank 100b. Further, as shown in FIGS. 4 to 6, a crank 106 is integrally connected to the leg 104, and a free end of the crank 106 is rotatably connected to a rod 110 of a lid moving cylinder 108. Yes. Accordingly, the lid body 102 is configured to move between a processing position covering the upper end opening of the inner tank 100b and a side retracted position in accordance with the operation of the lid body moving cylinder 108. . The surface (upper surface) of the lid 102 is provided with a nozzle plate 112 having a large number of injection nozzles 112a for injecting pure water outward (upward), for example.

  Further, as shown in FIG. 10, the first processing liquid supplied from the first processing liquid tank 120 as the first processing liquid pump 122 is driven is directed upward in the inner tank 100 b of the processing tank 100. The nozzle plate 124 having a plurality of spray nozzles 124a for spraying is disposed in a state where the spray nozzles 124a are more evenly distributed over the entire cross section of the inner tank 100b. A drain pipe 126 for discharging the first processing liquid (drainage) to the outside is connected to the bottom surface of the inner tank 100b. A three-way valve 128 is provided in the middle of the drain pipe 126, and the first treatment liquid (drainage liquid) is provided as necessary via a return pipe 130 connected to one outlet port of the three-way valve 128. ) Can be returned to the first treatment liquid tank 120 for reuse.

  The nozzle plate 112 provided on the surface (upper surface) of the lid 102 is connected to the second processing liquid supply source 132. Thereby, the second processing liquid is sprayed from the spray nozzle 112a toward the surface of the substrate. A drain pipe 127 is also connected to the bottom surface of the outer tub 100a.

  As a result, the processing head 60 holding the substrate is lowered, and the upper end opening of the inner tank 100b of the processing tank 100 is covered with the processing head 60, and in this state, the inside of the inner tank 100b of the processing tank 100 is covered. By spraying the first processing liquid from the spray nozzle 124a of the arranged nozzle plate 124 toward the substrate W, the first processing liquid is sprayed uniformly over the entire lower surface (processing surface) of the substrate W, and The first processing liquid is discharged from the drain pipe 126 to the outside while preventing the first processing liquid from scattering to the outside.

  Further, the processing head 60 is raised, and the upper end opening of the inner tank 100b of the processing tank 100 is closed with the lid 102, and is disposed on the upper surface of the lid 102 toward the substrate W held by the processing head 60. By spraying the second processing liquid from the spray nozzle 112a of the nozzle plate 112, the second processing liquid is sprayed uniformly over the entire lower surface (processing surface) of the substrate W. Since the second treatment liquid passes between the outer tank 100a and the inner tank 100b and is discharged through the drain pipe 127, the second treatment liquid is prevented from flowing into the inner tank 100b and becomes the first treatment liquid. Mixing is prevented.

  According to the catalyst application unit 15, as shown in FIG. 4, the substrate W is inserted and held in the state where the processing head 60 is raised, and then, as shown in FIG. 60 is moved down to be positioned so as to cover the upper end opening of the inner tank 100b of the processing tank 100. Then, while the processing head 60 is rotated and the substrate W held by the processing head 60 is rotated, the first processing is performed from the injection nozzle 124a of the nozzle plate 124 disposed inside the inner tank 100b as shown in FIG. By spraying the liquid toward the substrate W, the first processing liquid is sprayed uniformly over the entire surface of the substrate W. Then, the processing head 60 is raised and stopped at a predetermined position, and as shown in FIG. 6, the lid 102 that has been in the retracted position is moved to a position that covers the upper end opening of the inner tank 100 b of the processing tank 100. In this state, the second processing liquid is ejected from the ejection nozzle 112 a of the nozzle plate 112 disposed on the upper surface of the lid 102 toward the substrate W held and rotated by the processing head 60. Thereby, the process by the 1st process liquid and the 2nd process liquid of the board | substrate W can be performed, keeping two liquids not mixing.

  The electroless plating unit 16 is shown in FIGS. The electroless plating unit 16 includes a plating tank 200 (see FIGS. 15 and 17) and a substrate head 204 that is disposed above the plating tank 200 and holds the substrate W in a detachable manner.

  As shown in detail in FIG. 11, the substrate head 204 includes a housing portion 230 and a head portion 232, and the head portion 232 mainly includes a suction head 234 and a substrate receiver 236 that surrounds the suction head 234. It is configured. The housing portion 230 houses a substrate rotation motor 238 and a substrate receiving drive cylinder 240. The upper end of the output shaft (hollow shaft) 242 of the substrate rotation motor 238 is at the rotary joint 244, and the lower end is at the lower end. The rods of the substrate receiving drive cylinder 240 are connected to the suction head 234 of the head unit 232, respectively, and are connected to the substrate receiver 236 of the head unit 232. A stopper 246 that mechanically restricts the rise of the substrate receiver 236 is provided inside the housing portion 230.

  Here, a spline structure is adopted between the suction head 234 and the substrate receiver 236, and the substrate receiver 236 moves up and down relative to the suction head 234 in accordance with the operation of the substrate receiver driving cylinder 240. When the output shaft 242 is rotated by driving the rotation motor 238, the suction head 234 and the substrate receiver 236 are configured to rotate integrally with the rotation of the output shaft 242.

As shown in detail in FIG. 12 to FIG. 14, an adsorption ring 250 that adsorbs and holds the substrate W with the lower surface serving as a sealing surface is attached to the periphery of the lower surface of the adsorption head 234 via a pressing ring 251. A concave portion 250 a provided continuously in the circumferential direction on the lower surface of the nozzle and a vacuum line 252 extending in the suction head 234 communicate with each other through a communication hole 250 b provided in the suction ring 250. Thus, the substrate W is sucked and held by evacuating the concave portion 250a. Thus, by holding the substrate W by evacuating it with a small width (in the radial direction), By minimizing the influence (deflection, etc.) on the substrate W due to the vacuum and immersing the adsorption ring 250 in the electroless plating solution, not only the surface (lower surface) but also the edge of the substrate W are all electroless. It becomes possible to immerse in the plating solution. The substrate W is released by supplying N ₂ to the vacuum line 252.

  On the other hand, the substrate receiver 236 is formed in a bottomed cylindrical shape that opens downward, a peripheral wall is provided with a substrate insertion window 236a for inserting the substrate W therein, and a disc protruding inward at the lower end. A claw portion 254 is provided. Further, a projection piece 256 having a taper surface 256 a serving as a guide for the substrate W on the inner peripheral surface is provided on the upper portion of the claw portion 254.

  As a result, as shown in FIG. 12, the substrate W is inserted into the substrate receiver 236 from the substrate insertion window 236a with the substrate receiver 236 lowered. Then, the substrate W is guided by the tapered surface 256 a of the protruding piece 256, positioned, and placed and held at a predetermined position on the upper surface of the claw portion 254. In this state, the substrate receiver 236 is raised, and the upper surface of the substrate W placed and held on the claw portion 254 of the substrate receiver 236 is brought into contact with the suction ring 250 of the suction head 234 as shown in FIG. Next, the concave portion 250 a of the suction ring 250 is evacuated through the vacuum line 252, and the substrate W is sucked and held while the peripheral portion of the upper surface of the substrate W is sealed to the lower surface of the suction ring 250. Then, when performing the electroless plating process, as shown in FIG. 14, the substrate receiver 236 is lowered several millimeters, the substrate W is separated from the claw portion 254, and the state is held by suction holding only by the suction ring 250. Thereby, it can prevent that the peripheral part of the surface (lower surface) of the board | substrate W stops being plated by presence of the nail | claw part 254. FIG.

  FIG. 15 shows the details of the plating tank 200. The plating tank 200 is connected to a plating solution supply pipe 308 (see FIG. 17) at the bottom, and a plating solution recovery groove 260 is provided in the peripheral wall portion. Two rectifying plates 262 and 264 for stabilizing the flow of the electroless plating solution flowing upward are disposed inside the plating tank 200, and further introduced into the plating tank 200 at the bottom. A temperature measuring device 266 that measures the temperature of the electroless plating solution is installed. Moreover, the pH is 6 in the inside of the plating tank 200 located slightly above the liquid surface of the electroless plating solution held in the plating tank 200 on the outer peripheral surface of the peripheral wall of the plating tank 200 and slightly obliquely upward in the diameter direction. An injection nozzle 268 for injecting a stop liquid composed of a neutral liquid of -7.5, for example, pure water, is installed. As a result, after the electroless plating is completed, the substrate W held by the head unit 232 is pulled up slightly above the liquid surface of the electroless plating solution and stopped temporarily. In this state, pure water is supplied from the spray nozzle 268 toward the substrate W. (Stopping liquid) is sprayed to immediately cool the substrate W, thereby preventing the electroless plating from proceeding with the electroless plating solution remaining on the substrate W.

  Further, the upper end opening of the plating tank 200 is closed when the plating process is not performed at the time of idling or the like, so that the upper end opening of the plating tank 200 is closed and wasteful evaporation and heat dissipation of the plating solution in the plating tank 200 is performed. A plating tank cover 270 to be prevented is installed so as to be openable and closable.

  As shown in FIG. 17, the plating tank 200 extends from the plating solution storage tank 302 at the bottom, and is connected to a plating solution supply pipe 308 provided with a plating solution supply pump 304, a filter 305, and a three-way valve 306 in the middle. Yes. Further, the plating solution recovery groove 260 of the plating tank 200 is connected to a plating solution recovery pipe extending from the plating solution storage tank 302. Thus, during the plating process, the electroless plating solution is supplied into the plating tank 200 from the bottom, and the electroless plating solution overflowing the plating tank 200 is transferred from the plating solution recovery groove 260 to the plating solution storage tank 302. By collecting, the electroless plating solution can be circulated. A plating solution return pipe 312 that returns to the plating solution storage tank 302 is connected to one outlet port of the three-way valve 306. Thus, the electroless plating solution can be circulated even when waiting for plating.

  In particular, in this example, by controlling the plating solution supply pump 304, the flow rate of the electroless plating solution that circulates during the plating standby and the plating process can be individually set. That is, the circulation flow rate of the electroless plating solution during plating standby is, for example, 2 to 20 L / min, and the circulation flow rate of the electroless plating solution during plating is set, for example, to 0 to 10 L / min. This ensures a large circulation flow rate of the electroless plating solution during plating standby, keeps the temperature of the plating bath in the cell constant, and reduces the circulation flow rate of the electroless plating solution during the plating process. A protective film (plating film) having a uniform thickness can be formed.

  In the vicinity of the bottom of the plating tank 200, the temperature of the electroless plating solution introduced into the plating tank 200 is measured, and the temperature measurement for controlling the heater 316 and the flow meter 318 described below based on the measurement result. A vessel 266 is provided.

  In this example, the temperature is raised using a separate heater 316, the water passed through the flow meter 318 is used as a heat medium, and the heat exchanger 320 is installed in the electroless plating solution in the plating solution storage tank 302. Then, a heating device 322 for indirectly heating the plating solution and a stirring pump 324 for circulating and stirring the electroless plating solution in the plating solution storage tank 302 are provided. This is because, in electroless plating, the electroless plating solution may be used at a high temperature (about 80 ° C.), and this is to cope with this. According to this method, the in-line heating method is used. Compared to the above, it is possible to prevent unnecessary substances and the like from being mixed into a very delicate electroless plating solution.

  According to this example, when the electroless plating solution is plated in contact with the substrate W, the solution temperature is set so that the temperature of the substrate W is 70 to 90 ° C., and the variation range of the solution temperature is ± It is controlled to be within 2 ° C.

  The electroless plating unit 16 includes a plating solution extraction unit 330 that extracts the electroless plating solution in the plating solution storage tank 302, and the composition of the plating solution that the extracted electroless plating unit 16 has, for example, an absorptiometric method. , A plating solution composition analysis unit 332 for analyzing by titration, electrochemical measurement, or the like is provided. The plating solution composition analysis unit 332 measures the cobalt ion concentration by, for example, absorbance analysis, ion chromatography analysis, capillary electrophoresis analysis, or chelate titration analysis of the plating solution.

  The higher the temperature of the electroless plating solution is, the higher the plating speed becomes. If the temperature is too low, the plating reaction does not occur. Therefore, it is generally 60 to 95 ° C, preferably 65 to 85 ° C, and preferably 70 to 85 ° C. More preferably, it is 75 ° C. Basically, it is desirable not to lower the temperature once it is raised, regardless of whether or not plating is actually performed, and it is desirable to keep it at 55 ° C. or higher.

  FIG. 16 shows the details of the cleaning tank 202 attached to the side of the plating tank 200. A plurality of injection nozzles 280 for injecting a rinse liquid such as pure water upward are attached to the nozzle plate 282 at the bottom of the cleaning tank 202, and the nozzle plate 282 is arranged at the upper end of the nozzle vertical axis 284. It is connected to. Further, the nozzle vertical shaft 284 moves up and down by changing the screwing position of the nozzle position adjusting screw 287 and the nut 288 screwed to the screw 287, whereby the jet nozzle 280 and the jet nozzle 280 are moved. The distance from the substrate W arranged above can be adjusted optimally.

  Further, a cleaning liquid such as pure water is sprayed into the cleaning tank 202 at a position slightly above the diametrical direction, slightly above the spray nozzle 280 on the outer peripheral surface of the peripheral wall of the cleaning tank 202, and the head of the substrate head 204. A head cleaning nozzle 286 for spraying the cleaning liquid on at least a portion in contact with the plating solution of the part 232 is installed.

  In this cleaning tank 202, the substrate W held by the head portion 232 of the substrate head 204 is disposed at a predetermined position in the cleaning tank 202, and a cleaning liquid (rinsing liquid) such as pure water is sprayed from the spray nozzle 280. Then, the substrate W is cleaned (rinsed). At this time, a cleaning liquid such as pure water is simultaneously ejected from the head cleaning nozzle 286, and a portion of the head portion 232 of the substrate head 204 that is in contact with at least the electroless plating solution. By washing with the washing solution, it is possible to prevent the deposits from accumulating in the portion immersed in the electroless plating solution.

In the electroless plating unit 16, the substrate W is adsorbed and held by the head portion 232 of the substrate head 204 at the position where the substrate head 204 is lifted as described above, and the electroless plating solution in the plating tank 200. Keep circulating.
When performing the plating process, the plating tank cover 270 of the plating tank 200 is opened, the substrate head 204 is lowered while rotating, and the substrate W held by the head portion 232 is immersed in the electroless plating solution in the plating tank 200. .

  Then, after immersing the substrate W in the plating solution for a predetermined time, the substrate head 204 is raised, the substrate W is pulled up from the electroless plating solution in the plating tank 200, and if necessary, as described above, the substrate The substrate W is immediately cooled by spraying pure water (stopping liquid) from the spray nozzle 268 toward W, and the substrate head 204 is further lifted to pull the substrate W up to a position above the plating tank 200. Stop rotation.

  Next, the substrate head 204 is moved to a position directly above the cleaning tank 202 while the substrate W is sucked and held by the head portion 232 of the substrate head 204. Then, while rotating the substrate head 204, the substrate head 204 is lowered to a predetermined position in the cleaning tank 202, and a cleaning liquid (rinsing liquid) such as pure water is sprayed from the spray nozzle 280 to clean (rinse) the substrate W. A cleaning liquid such as pure water is sprayed from the cleaning nozzle 286, and at least a portion of the head portion 232 of the substrate head 204 that comes into contact with the electroless plating solution is cleaned with the cleaning liquid.

  After the cleaning of the substrate W is completed, the rotation of the substrate head 204 is stopped, the substrate head 204 is raised, the substrate W is pulled up to a position above the cleaning tank 202, and the substrate head 204 is further moved to the second substrate transport robot 26. The substrate W is transferred to the second substrate transfer robot 26 and transferred to the next process.

  FIG. 18 shows the drying unit 20. The drying unit 20 is a unit that first performs chemical cleaning and pure water cleaning, and then completely drys the cleaned substrate W by rotating the spindle, and includes a clamp mechanism 420 that grips the edge portion of the substrate W. A substrate stage 422 and a substrate attaching / detaching lifting plate 424 for opening and closing the clamp mechanism 420 are provided. The substrate stage 422 is connected to the upper end of a spindle 428 that rotates at a high speed as the spindle rotation motor 426 is driven.

Further, a mega jet nozzle 430 that is located on the upper surface side of the substrate W gripped by the clamp mechanism 420 and that supplies pure water with enhanced cleaning effect by transmitting ultrasonic waves when passing through a special nozzle by an ultrasonic oscillator; A rotatable pencil-type cleaning sponge 432 is attached and arranged on the free end side of the swivel arm 434. Accordingly, the cleaning sponge 432 is supplied to the surface of the substrate W while supplying the pure water from the mega jet nozzle 430 toward the cleaning sponge 432 while rotating the swivel arm 434 while holding the substrate W by the clamp mechanism 420 and rotating it. The surface of the substrate W is cleaned by rubbing. A cleaning nozzle (not shown) for supplying pure water is also provided on the back surface side of the substrate W, and the back surface of the substrate W is simultaneously cleaned with pure water sprayed from the cleaning nozzle.
The substrate W thus cleaned is spin-dried by rotating the spindle 428 at a high speed.

Further, a cleaning cup 436 is provided that surrounds the periphery of the substrate W gripped by the clamp mechanism 420 and prevents the processing liquid from being scattered. The cleaning cup 436 moves up and down in accordance with the operation of the cleaning cup lifting and lowering cylinder 438. It has become.
The drying unit 20 may also be equipped with a cavitation function using cavitation.

Next, a series of processes (electroless plating process) by this electroless plating apparatus will be described with reference to FIG.
First, the substrate W having the wiring 8 formed on the surface thereof is stored in the load / unload unit 11 with the surface of the substrate W facing upward (face up), and one substrate W is transferred to the first substrate. The robot 24 takes it out and transports it to the temporary table 22 and places it on the temporary table 22. The substrate W placed on the temporary table 22 is transferred to the pre-cleaning unit 14 by the second substrate transfer robot 26.

  The pre-cleaning unit 14 holds the substrate W face up and performs pre-cleaning on the surface of the substrate W by combining the chemical action by the cleaning liquid and the mechanical action by the cleaning member (scrubbing). The remaining anticorrosive and / or metal complex is completely removed. In this example, in order to remove an anticorrosive agent such as BTA (benzotriazole) and / or a metal complex, an organic solution having a pH of 3 or more (pH> 3) containing ethylenediaminediacetic acid (EDTA) in an aqueous solution of citric acid is used as a cleaning solution. Use an acid solution.

  In other words, the cleaning member (roll brush) 42 is brought into contact with the surface of the rotating substrate W wetted with pure water while rotating, and the cleaning member (roll brush) 42 contacts the surface of the substrate W. At the same time, from the cleaning liquid nozzle 32 disposed above the substrate W, an organic acid solution having a pH of 3 or more (pH> 3) containing ethylenediaminediacetic acid (EDTA) in an aqueous citric acid solution is applied to the surface of the substrate W. Supply a cleaning solution. Thereby, the anticorrosive agent and / or metal complex remaining on the surface of the substrate W is completely removed by the pre-cleaning that combines the chemical action by the cleaning liquid and the mechanical action by the cleaning member 42. In parallel with the pre-cleaning of the front surface (upper surface) of the substrate, pre-cleaning of the back surface (lower surface) of the substrate is performed as necessary.

  Then, after performing the above-described treatment for a predetermined time, for example, 30 seconds, the surface of the substrate W is rinsed with pure water supplied from the pure water nozzle 38, and the back surface of the substrate W is similarly purified as necessary. Rinse with pure water supplied from the water nozzle 38.

  Next, the substrate after pre-cleaning is transported to the catalyst application unit 15, the substrate W is held face down by the substrate holder 58 of the catalyst application unit 15, and, for example, a Pd catalyst application liquid is brought into contact with the surface of the substrate. A catalyst is applied to the surface of the wiring 8. That is, as shown in FIG. 6, the processing head 60 is positioned at a position covering the upper end opening of the inner tank 100 b, and the spray nozzle 112 a of the nozzle plate 112 disposed in the inner tank 100 b is placed in the first processing liquid tank 120. The first processing liquid is ejected toward the substrate W. For example, a Pd catalyst application liquid is used as the first treatment liquid, and thereby a catalyst is applied to the surface of the wiring 8. As the catalyst metal, any of platinum group elements, cobalt, and nickel can be used, but Pd is preferably used as the catalyst from the viewpoint of reaction rate and ease of control.

  At this time, it is preferable that the surface of the substrate after the pre-cleaning is rinsed with pure water, and the surface of the substrate is brought into contact with the catalyst applying liquid before the surface of the substrate is completely dried. This prevents the formation of an oxide film on the wiring surface or the formation of a watermark between the pre-cleaning process and the start of the catalyst application process, thereby uniformly applying the catalyst to the wiring surface. Then, it is possible to prevent a defect from occurring in the protective film (plating film) formed by subsequent electroless plating.

  After applying a catalyst such as Pd to the surface of the wiring 8 by the catalyst applying unit 15, the surface of the substrate is washed (rinsed) with pure water. That is, the substrate holder 58 holding the substrate W is raised to above the inner tank 100b, the upper part of the inner tank 100b is covered with the lid body 102, and then the second from the injection nozzle 112a of the nozzle plate 112 provided on the lid body 102. The processing liquid is ejected toward the substrate W. As the second treatment liquid, preferably degassed pure water is used, and thereby the surface of the substrate W is cleaned (rinsed) with pure water.

  Next, the substrate W after the catalyst application treatment is transported to the electroless plating unit 16. In the electroless plating unit 16, the substrate head 204 holding the substrate W face down is lowered, and the substrate W is immersed in the electroless plating solution in the plating tank 200, whereby electroless plating (electroless CoWP lid) Plating). That is, for example, selective electroless plating (electroless CoWP lid plating) is performed on the surface of the wiring 8 activated by immersing the substrate W in a CoWP plating solution having a liquid temperature of 80 ° C. for about 120 seconds, for example. Apply.

  Then, after pulling up the substrate W from the surface of the plating solution, a plating stop solution such as pure water is ejected from the injection nozzle 268 toward the substrate W, thereby replacing the plating solution on the surface of the substrate W with the stop solution. To stop the electroless plating. Next, the substrate head 204 holding the substrate W is positioned at a predetermined position in the cleaning tank 202, and pure water is ejected from the spray nozzle 280 of the nozzle plate 282 in the cleaning tank 202 toward the substrate W. W is washed (rinsed), and at the same time, pure water is jetted from the head washing nozzle 286 to the head part 232 to wash the head part 232. Thus, the protective film 9 made of a CoWP alloy film is selectively formed on the surface of the wiring 8 to protect the wiring 8.

  Next, the substrate W after the electroless plating process is transported to the post-cleaning unit 18 by the second substrate transport robot 26, where the selectivity of the protective film (metal film) 9 formed on the surface of the substrate W is increased. Apply post-plating treatment (post-cleaning) to improve and increase yield. In other words, a post-plating processing solution (chemical solution) is supplied to the surface of the substrate W while applying a physical force by, for example, roll scrub cleaning or pencil cleaning to the surface of the substrate W, whereby an insulating film (interlayer insulating film) 2 to completely remove plating residues such as metal fine particles remaining on the metal plate, thereby improving the selectivity of plating.

Then, the substrate W after the post-plating treatment is transported to the drying unit 20 by the second substrate transport robot 26, where rinsing is performed as necessary, and then the substrate W is rotated at a high speed and spin-dried. .
The substrate W after the spin drying is placed on the temporary table 22 by the second substrate transport robot 26, and the substrate placed on the temporary table 22 is loaded / unloaded by the first substrate transport robot 24. Return to the substrate cassette mounted on.

  According to this example, when a protective film is formed after applying a catalyst to the wiring surface, the chemical action by the cleaning liquid and the mechanical action by the cleaning member are combined prior to the process of applying the catalyst to the wiring surface. In addition, the anti-corrosion agent and / or metal complex remaining on the surface of the substrate is completely removed by pre-cleaning to provide a uniform catalyst on the wiring surface, and protection is provided in the absence of the anti-corrosion agent and / or metal complex on the wiring surface. A film can be formed.

  FIG. 20 is a plan layout view of an electroless plating apparatus according to another embodiment of the present invention. The example shown in FIG. 20 is different from the example shown in FIG. 1 in that a cleaning unit 14a and a pretreatment unit 15a are provided in the apparatus frame 12 instead of the precleaning unit 14 and the catalyst application unit 15 shown in FIG. It is at the point where it was placed. The cleaning unit 14a has the same configuration as the catalyst application unit 15 shown in FIG. 1 except that the processing liquid used is different. The preprocessing unit 15a differs only in the processing liquid used, as shown in FIG. 14 is the same configuration.

  In this example, after the substrate surface is cleaned by the cleaning unit 14a, the substrate is pre-processed by the pre-processing unit 15a, that is, the substrate surface is cleaned and the catalyst is applied to the wiring surface at the same time. A protective film on the surface of the wiring is selectively formed by the plating unit 16.

  That is, as shown in FIG. 21, a substrate W is taken out from the substrate cassette that is stored in the loading / unloading unit 11 and transferred to the temporary placement table 22 by the first substrate transfer robot 24. Place on the table 22. The substrate W placed on the temporary table 22 is transported to the cleaning unit 14 a by the second substrate transport robot 26.

  In this cleaning unit 14a, the cleaning liquid is used in place of the first processing liquid (catalyst applying liquid) in the catalyst applying unit 15 described above, and the cleaning liquid is sprayed toward the surface of the substrate held face down, so that the surface of the substrate Then, the surface of the cleaned substrate W is rinsed with pure water. And the board | substrate after washing | cleaning is conveyed to the pre-processing unit 15a.

  In this pretreatment unit 15a, a pretreatment liquid containing a catalyst (catalyst imparting and washing liquid) is used instead of the washing liquid in the aforementioned precleaning unit 14, and the surface of the substrate W held face-up is chemically treated with the pretreatment liquid. Cleaning and catalyst application treatment that combines mechanical action and mechanical action by the cleaning member (scrub cleaning) are simultaneously performed to completely remove the anticorrosive agent and / or metal complex remaining on the surface of the substrate, and at the same time, the surface of the wiring The catalyst is added to

In other words, the cleaning member (roll brush) 42 (see FIG. 3) is brought into contact with the surface of the rotating substrate W wetted with pure water while the cleaning member (roll brush) 42 is rotated. Simultaneously with contact with the surface of W, a pretreatment liquid (catalyst application / cleaning liquid) is supplied to the surface of the substrate W from a cleaning liquid nozzle 32 (see FIG. 3) disposed above the substrate W.
And after performing the said process for predetermined time, for example, 30 seconds, the surface of the board | substrate W is rinsed with a pure water, and the back surface of the board | substrate W is similarly rinsed with a pure water as needed.

  At this time, it is preferable to rinse the surface of the substrate after cleaning with pure water and bring the surface of the substrate into contact with the pretreatment liquid before the surface of the substrate is completely dried. This prevents the formation of an oxide film on the wiring surface or the formation of a watermark between the cleaning process and the start of the pretreatment, and uniformly applies the catalyst to the wiring surface. It is possible to prevent a defect from occurring in the protective film (plating film) formed by electroless plating.

Next, the substrate after the pretreatment is transported to the electroless plating unit 16 where selective electroless plating is performed on the surface of the wiring 8. The subsequent processing is the same as in the above example.
In this way, the multi-step process combining the cleaning unit 14a and the pre-processing unit 15a can be performed to further enhance the substrate cleaning effect.

  According to this example, when a protective film is formed on the wiring surface after the substrate surface is cleaned and the catalyst is applied to the wiring surface at the same time using one pretreatment liquid, electroless plating is used. Prior to film formation, the anticorrosive and / or metal complex remaining on the surface of the substrate can be completely removed by pretreatment that combines the chemical action of the pretreatment liquid and the mechanical action of the cleaning member. In addition, pretreatment over the entire surface of the substrate can be performed by bringing the cleaning member into contact with the surface of the substrate and relatively moving both of them.

  Depending on the type of alloy film that forms the protective film selectively formed on the surface of the wiring, there is a type in which the protective film (alloy film) can be directly formed on the surface of the substrate without applying a catalyst. When such an alloy film is used as a protective film, as the pretreatment liquid of the pretreatment unit 15a shown in FIG. 20, for example, an ethylenediaminediacetic acid solution in an aqueous solution of citric acid, as in the case of the precleaning unit 14 described above. A cleaning solution comprising an organic acid solution containing (EDTA) and having a pH of 3 or more (pH> 3) is used. Then, as shown in FIG. 22, the substrate W taken out from the substrate cassette mounted on the load / unload unit 11 and transported to the temporary placement table 22 is transported to the pretreatment unit 15a. Anti-corrosion agent remaining on the surface of the substrate by pre-cleaning the surface of the substrate W by combining the chemical action of the pretreatment liquid (cleaning liquid) and the mechanical action of the cleaning member (scrubbing). And / or metal complexes and the like are completely removed. Then, the surface of the substrate W is rinsed with pure water, and the back surface of the substrate W is similarly rinsed with pure water as necessary, and then transferred to the electroless plating unit 16 where the surface of the wiring 8 is selected. A typical electroless plating may be applied. The subsequent processing is the same as in the above example.

Even in this case, the substrate may be pre-processed (cleaned) by the pre-processing unit 15a after the substrate is cleaned by the cleaning unit 14a.
Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

  In the above example, while supplying the cleaning liquid (pretreatment liquid) to the surface or both surfaces of the substrate W, while rotating the roll-shaped cleaning members 42 and 46 around the rotation shafts 40 and 44 in the same direction, The surface is brought into contact with the surface or both surfaces of the substrate W to perform pre-cleaning (pre-processing) of the substrate W. While supplying the cleaning liquid (pre-processing solution) to the surface or both surfaces of the substrate, the swing arm The substrate may be pre-cleaned (pre-processed) by bringing a rotatable cleaning member attached to the tip of the substrate into contact with the substrate rotating in the horizontal direction. In addition, a rotatable cleaning member attached to the tip of the swing arm is brought into contact with a substrate that rotates in a horizontal direction, and a liquid having ultrasonic vibrations is sprayed toward the surface of the substrate to pre-clean the substrate. (Pre-processing) may be performed. Furthermore, the front surface or both surfaces of the substrate may be polished with a buff or the like to perform pre-cleaning (pre-processing) of the substrate.

Example 1
The sample was pre-cleaned using the pre-cleaning unit 14 shown in FIG. 1, and the cleaning effect was examined. First, a 300 mm copper blanket wafer was prepared as a sample by uniformly forming a 1000 nm copper film on the surface by electrolytic plating, leaving the copper film 500 nm, and polishing it by CMP. Benzotriazole (BTA) remains on the copper surface of the sample after CMP.

  Then, the surface to be treated (surface) was faced upward, the sample was held by the roller 30 of the pre-cleaning unit 14, and the entire surface of the sample was wetted with pure water for 5 seconds while rotating the sample at 110 rpm. Then, the cleaning member (roll brush) 42 was brought into contact with the surface of the sample while rotating at 100 rpm. At the same time as the cleaning member 42 comes into contact with the surface of the sample, a cleaning liquid made of an organic acid solution having a pH of 3 or more (pH> 3) containing ethylenediaminediacetic acid (EDTA) in an aqueous citric acid solution is extracted from the cleaning liquid nozzle 32. The sample was supplied to the surface, and the sample was cleaned (pre-cleaned) for 30 seconds. Thereafter, the sample was separated from the roller 30, and immediately the surface of the sample was rinsed with pure water for 15 seconds.

(Comparative Example 1)
A sample similar to that in Example 1 was prepared, and the sample was washed by a so-called spray method. That is, the sample is set in a spray-type cleaning unit with the surface to be processed (surface) facing down, and the sample is horizontally rotated at 20 rpm, and the aqueous solution of citric acid is supplied from a plurality of spray nozzles arranged below the sample. A cleaning liquid composed of an organic acid solution containing ethylenediaminediacetic acid (EDTA) having a pH of 3 or more (pH> 3) was sprayed toward the entire surface of the sample, and the sample was cleaned (pre-cleaning) for 30 seconds. . Thereafter, the entire surface of the sample was rinsed with pure water for 15 seconds.

(Comparative Example 2)
A sample similar to that in Example 1 was prepared, and the sample was washed by a so-called dipping method. In other words, the surface to be treated (surface) is facing downward, the sample is set in an immersion type cleaning unit, and the pH of the aqueous citric acid solution containing ethylenediaminediacetic acid (EDTA) is 3 or more while rotating the sample horizontally at 20 rpm. The sample was immersed in a cleaning solution composed of an organic acid solution (pH> 3), and the sample was cleaned (pre-cleaning) for 60 seconds. Thereafter, the sample was pulled up from the cleaning solution, and its surface was rinsed with pure water for 15 seconds.

この表１から、実施例１によれは、比較例１及び２に比較して、１枚の試料に対して使用される洗浄液（薬液）が少なくて済むことが判る。 Table 1 summarizes the processing conditions in Example 1 and Comparative Examples 1 and 2.

From Table 1, it can be seen that, according to Example 1, less cleaning liquid (chemical solution) is used for one sample as compared with Comparative Examples 1 and 2.

  Chips were cut out from the samples after the treatment in Example 1 and Comparative Examples 1 and 2, respectively, and subjected to X-ray photoelectron spectroscopy (XPS) analysis. Table 2 shows the relative values of the N element and O element detected by this analysis.

Ｎ元素及びＯ元素は、それぞれＢＴＡの残留量および金属酸化物に比例すると考えられる。この表２から、実施例１は、比較例１及び２に比較して、防食材であるＢＴＡまたはＣｕ−ＢＴＡ錯体および金属酸化物の除去に有効であることが判る。

N element and O element are considered to be proportional to the residual amount of BTA and the metal oxide, respectively. From Table 2, it can be seen that Example 1 is more effective in removing BTA or Cu-BTA complexes and metal oxides as anticorrosive materials than Comparative Examples 1 and 2.

(Example 2)
A 300 mmφ pattern wafer in which the exposed surface of the copper wiring was formed by CMP was prepared as a sample. Benzotriazole (BTA) remains on the surface of the copper wiring after CMP.
The surface of this sample was washed (pre-washed) in the same manner as in Example 1 and rinsed with pure water. Next, the sample after the pre-cleaning is carried into an electroless plating unit, and the sample is immersed in an electroless plating solution having a pH of 8 or more (pH> 8) containing inorganic salts of Co and W and DMAB, and copper A protective film was formed on the surface of the wiring. After elapse of a predetermined time, the sample was pulled up from the electroless plating solution, and immediately the entire surface of the sample was rinsed with pure water for 5 seconds. Thereafter, the sample was washed and dried.

(Comparative Example 3)
A sample similar to that in Example 2 was prepared, and the surface of this sample was washed (pre-washed) in the same manner as in Comparative Example 1 and rinsed with pure water. Then, a protective film was formed on the surface of the wiring of the sample after this cleaning (after pre-cleaning) in the same manner as in Example 2, and was dried after cleaning.

(Comparative Example 4)
A sample similar to that in Example 2 was prepared, and the surface of this sample was washed (pre-cleaned) in the same manner as in Comparative Example 2 and rinsed with pure water. Then, a protective film was formed on the surface of the wiring of the sample after this cleaning (after pre-cleaning) in the same manner as in Example 2, and was dried after cleaning.

  The film thickness at a representative location of the protective film (Co alloy film) formed on the copper wiring according to Example 2 and Comparative Examples 3 and 4 was measured by an optical thin film measuring instrument. Table 3 shows the average value and non-uniformity (3σ) of the thickness of the protective film obtained from the measurement results.

表３から、実施例２にあっては、比較例３及び４に比較して、配線上に形成した保護膜の面内均一性が良いことが判る。

From Table 3, it can be seen that in Example 2, the in-plane uniformity of the protective film formed on the wiring is better than in Comparative Examples 3 and 4.

(Example 3)
A sample similar to that in Example 2 was prepared, and the surface of the sample was washed (pre-washed) in the same manner as in Example 1 and rinsed with pure water. Next, the sample was carried into the catalyst processing unit, and the sample was immersed in a catalyst application liquid composed of an aqueous sulfuric acid solution containing PdSO _{4 and having} a pH of 2 or less (pH <2), and the sample was pulled up from the catalyst application liquid after a predetermined time. . Then, the sample surface was immediately rinsed with pure water for 10 seconds. Thereafter, the sample is carried into an electroless plating unit, and the sample is immersed in an electroless plating solution having a pH of 8 or more (pH> 8) containing inorganic salts of Co and W and hypophosphite. A protective film was formed on the surface. After elapse of a predetermined time, the sample was pulled up from the electroless plating solution, and immediately the entire surface of the sample was rinsed with pure water for 5 seconds. Thereafter, the sample was washed and dried.

(Comparative Example 5)
A sample similar to that in Example 2 was prepared, and the surface of the sample was washed (pre-washed) in the same manner as in Comparative Example 1 and rinsed with pure water. Then, a protective film was formed on the surface of the wiring of the sample after this cleaning (after pre-cleaning) in the same manner as in Example 3, and was dried after cleaning.

(Comparative Example 6)
A sample similar to that in Example 2 was prepared, and the surface of the sample was washed (pre-washed) in the same manner as in Comparative Example 2 and rinsed with pure water. Then, a protective film was formed on the surface of the wiring of the sample after this cleaning (after pre-cleaning) in the same manner as in Example 3, and was dried after cleaning.

  The film thickness at the representative location of the protective film (Co alloy film) formed on the copper wiring in Example 3 and Comparative Examples 5 and 6 was measured with an optical thin film measuring instrument. Table 4 shows the average value and non-uniformity (3σ) of the thickness of the protective film obtained from this measurement result.

表３から、実施例３にあっては、比較例５及び６に比較して、配線上に形成した保護膜の面内均一性が良いことが判る。

From Table 3, it can be seen that in Example 3, the in-plane uniformity of the protective film formed on the wiring is better than in Comparative Examples 5 and 6.

  Next, the leakage current of the wiring processed in Example 3 and Comparative Examples 5 and 6 was measured. The distribution is shown in FIG. This figure also shows the leakage current distribution in the wiring of the sample that is not treated as a reference. Here, the device performance is required not to shift in the direction in which the leakage current increases. As shown in FIG. 23, in Example 3, compared with Comparative Examples 5 and 6, the leakage current in the wiring on which the protective film is formed is closest to the leakage current in the wiring that has not been processed. Thereby, according to Example 3, it can be seen that impurities remaining on the surface of the sample can be effectively removed, and the lowest value of the leakage of the wiring after plating can be obtained.

1 is a plan layout view showing an electroless plating apparatus according to an embodiment of the present invention. It is a top view of the pre-cleaning unit of the electroless-plating apparatus shown in FIG. It is a schematic sectional drawing of the pre-cleaning unit of the electroless-plating apparatus shown in FIG. It is the front view which abbreviate | omitted the outer tank at the time of board | substrate delivery of the catalyst provision unit of the electroless-plating apparatus shown in FIG. It is the front view which abbreviate | omitted the outer tank at the time of the process by the 1st process liquid of the catalyst provision unit of the electroless-plating apparatus shown in FIG. It is the front view which abbreviate | omitted the outer tank at the time of the process by the 2nd process liquid of the catalyst provision unit of the electroless-plating apparatus shown in FIG. It is sectional drawing which shows the process head at the time of board | substrate delivery of the catalyst provision unit of the electroless-plating apparatus shown in FIG. It is the A section enlarged view of FIG. FIG. 9 is a view corresponding to FIG. 8 when the substrate of the catalyst application unit of the electroless plating apparatus shown in FIG. 1 is fixed. It is a systematic diagram of the catalyst provision unit of the electroless-plating apparatus shown in FIG. It is sectional drawing which shows the board | substrate head at the time of board | substrate delivery of the electroless-plating unit of the electroless-plating apparatus shown in FIG. It is the B section enlarged view of FIG. FIG. 13 is a view corresponding to FIG. 12 showing the substrate head when the substrate of the electroless plating unit of the electroless plating apparatus shown in FIG. 1 is fixed. FIG. 13 is a view corresponding to FIG. 12 showing the substrate head during the plating process of the electroless plating unit of the electroless plating apparatus shown in FIG. 1. It is a partially cut front view which shows a plating tank when the plating tank cover of the electroless plating unit of the electroless plating apparatus shown in FIG. 1 is closed. It is sectional drawing which shows the washing tank of the electroless-plating unit of the electroless-plating apparatus shown in FIG. It is a systematic diagram of the electroless plating unit of the electroless plating apparatus shown in FIG. It is a vertical front view which shows the drying unit of the electroless-plating apparatus shown in FIG. It is a flowchart which shows the process in the electroless-plating apparatus shown in FIG. It is a plane | planar arrangement | positioning figure which shows the electroless-plating apparatus of other embodiment of this invention. It is a flowchart which shows the process in the electroless-plating apparatus shown in FIG. It is a flowchart which shows the other process in the electroless-plating apparatus shown in FIG. 6 is a graph showing a leakage current distribution of wirings in Example 3 and Comparative Examples 5 and 6. It is a figure which shows the conventional copper damascene wiring structure. It is a figure which shows the example of forming a protective film selectively on the surface of wiring by electroless plating in order of a process. It is a figure which shows the copper wiring formation example in a semiconductor device in order of a process. It is a flowchart which shows the process of forming a protective film selectively on the surface of the conventional wiring.

Explanation of symbols

8 Wiring 9 Protective film 11 Load / unload unit 12 Device frame 14 Pre-cleaning unit 14a Cleaning unit 15 Catalyst applying unit 15a Pre-processing unit 16 Electroless plating unit 18 Post-cleaning unit 20 Drying unit 30 Rollers 32, 36 Cleaning liquid nozzle 34 , 38 Nozzle for pure water 40 Rotating shaft 40, 44 Rotating shaft 42, 46 Cleaning member 48 Sponge 58 Substrate holder 60 Processing head 84 Seal ring 86 Substrate fixing ring 92 Bellows plate 94 Coating plate 100 Processing tank 102 Cover body 200 Plating tank 202 Cleaning tank 204 Substrate head 230 Housing portion 232 Head portion 234 Suction head

Claims (9)

Prepare a board with embedded wiring inside,
The cleaning member is brought into contact with the surface or both sides of the wet substrate, and the pretreatment is performed by supplying a pretreatment liquid to the surface or both sides of the substrate while relatively moving both.
An electroless plating method comprising selectively forming a protective film on a surface of a wiring by bringing the surface of the substrate into contact with an electroless plating solution.   2. The electroless plating method according to claim 1, wherein the surface of the substrate after the pretreatment is rinsed with pure water, and the surface of the substrate is brought into contact with an electroless plating solution before the surface of the substrate is completely dried. . Prepare a board with embedded wiring inside,
The cleaning member is brought into contact with the surface or both surfaces of the wet substrate, and the substrate is pre-cleaned by supplying a cleaning liquid to the surface or both surfaces of the substrate while relatively moving both of them.
The surface of the substrate after pre-cleaning is brought into contact with the catalyst application liquid to apply the catalyst to the surface of the wiring, and then,
An electroless plating method comprising selectively forming a protective film on a surface of a wiring by bringing the surface of the substrate into contact with an electroless plating solution.   The electroless plating method according to claim 3, wherein the surface of the substrate after the pre-cleaning is rinsed with pure water, and the surface of the substrate is brought into contact with a catalyst applying liquid before the surface of the substrate is completely dried. A pretreatment unit that performs pretreatment by supplying a pretreatment liquid to the surface or both surfaces of the substrate while bringing the cleaning member into contact with the surface or both surfaces of the wet substrate and relatively moving both;
An electroless plating apparatus comprising an electroless plating unit that selectively forms a protective film on a surface of a wiring by bringing the surface of the substrate into contact with an electroless plating solution. A pre-cleaning unit that precleans the substrate by supplying a cleaning liquid to the surface or both surfaces of the substrate while bringing the cleaning member into contact with the surface or both surfaces of the wet substrate and relatively moving both;
A catalyst application unit that applies the catalyst to the surface of the wiring by bringing the surface of the substrate after pre-cleaning into contact with the catalyst application liquid;
An electroless plating apparatus comprising an electroless plating unit that selectively forms a protective film on a surface of a wiring by bringing the surface of the substrate into contact with an electroless plating solution.   The electroless plating apparatus according to claim 5, further comprising a cleaning unit that immerses the substrate in a cleaning solution or sprays the cleaning solution toward the substrate to clean the substrate.   The electroless plating apparatus according to any one of claims 5 to 7, wherein the cleaning member is made of polyvinyl alcohol having a porous continuous pore structure or a fluororesin material.   The electroless plating apparatus according to claim 5, wherein the cleaning member is a roll-shaped brush having a rotation shaft at the center.

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