JP2004260106A - Method and apparatus for treating substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture semiconductor devices or the like at a high yield while maintaining reproducibility within a substrate such as a semiconductor wafer or the like and among the substrates. <P>SOLUTION: The method to be provided comprises a step of making a pretreatment for plating on the substrate prior to selectively forming a protective film on the bottom face and the side faces or on the exposed surface of an buried interconnect formed on the surface of the substrate, a step of selectively forming the protective film on the bottom face and the side faces, or on the exposed surface of the interconnect by carrying out electroless plating on the surface of the pretreated substrate, a step of making a post-treatment for enhancing the selectivity on the protective film as needed, and a step of drying the substrate. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a substrate processing method and a substrate processing apparatus, and more particularly to a bottom surface of an embedded wiring formed by embedding a conductor such as copper or silver in a fine recess for wiring provided on the surface of a substrate such as a semiconductor wafer. And a conductive film having a function of preventing thermal diffusion of the wiring material into the interlayer insulating film or a function of improving the adhesion between the wiring and the interlayer insulating film, a magnetic film covering the wiring, or the like, on the side surface or the exposed surface. The present invention relates to a substrate processing method and a substrate processing apparatus used for forming a protective film by electroless plating.
[0002]
[Prior art]
As a wiring forming process of a semiconductor device, a process (so-called damascene process) in which a metal (conductor) is embedded in a wiring groove and a contact hole is being used. This is because a metal such as aluminum, recently copper or silver is buried in a wiring groove or a contact hole previously formed in an interlayer insulating film, and then excess metal is removed by chemical mechanical polishing (CMP) to planarize the metal. Process technology.
[0003]
Conventionally, in the case of this type of wiring, for example, copper wiring using copper as a wiring material, in order to improve reliability, thermal diffusion of wiring (copper) to an interlayer insulating film is prevented and electromigration resistance is improved. Film is formed on the bottom and side surfaces of the wiring for preventing the wiring (copper) from being oxidized in an oxidizing atmosphere when a semiconductor device having a multilayer wiring structure is formed by laminating an insulating film (oxide film) thereafter. For this purpose, a method such as forming an antioxidant film is employed. Conventionally, a metal such as tantalum, titanium or tungsten or a nitride thereof has been generally adopted as a barrier film of this type, and a nitride of silicon or the like has been generally adopted as an antioxidant film.
[0004]
An alternative to this is to prevent thermal diffusion, electromigration and oxidation of the wiring by recently selectively covering the bottom and side surfaces or the exposed surface of the buried wiring with a wiring protective film made of cobalt alloy, nickel alloy, etc. It is considered to be. In a nonvolatile magnetic memory, in order to suppress an increase in write current due to miniaturization, it is considered that the periphery of the recording wiring is covered with a magnetic film such as a cobalt alloy or a nickel alloy. This cobalt alloy, nickel alloy, or the like is obtained by, for example, electroless plating.
[0005]
Here, for example, as shown in FIG. 1, SiO deposited on the surface of a substrate W such as a semiconductor wafer ₂ A fine concave portion 4 for wiring is formed inside an insulating film 2 made of, for example, and a barrier layer 6 made of TaN or the like is formed on the surface. Then, for example, copper plating is performed to form a copper film on the surface of the substrate W. A film 8 is formed and buried in the recess 4, and thereafter, the surface of the substrate W is subjected to CMP (chemical mechanical polishing) to be flattened, thereby forming a wiring 8 made of a copper film inside the insulating film 2. In the case where the wiring 8 is protected by selectively forming a wiring protection film (cover material) 9 made of a Co—WP alloy film, which is obtained by, for example, electroless plating, on the surface of the wiring (copper film) 8. think of.
[0006]
The step of selectively forming the wiring protection film (cover material) 9 made of such a Co-WP alloy film on the surface of the wiring 8 by general electroless plating will be described. First, a CMP treatment is performed. The substrate W such as a semiconductor wafer or the like is immersed in, for example, normal temperature diluted sulfuric acid for about 1 minute to remove a CMP residue such as copper remaining on the surface of the insulating film 2. Then, after cleaning the surface of the substrate W with a cleaning liquid such as pure water, for example, PdCl ₂ The substrate W is immersed for about one minute in the / HCl mixed solution, whereby Pd as a catalyst is attached to the surface of the wiring 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, the activated wiring is immersed in, for example, a Co-WP plating solution having a liquid temperature of 80 ° C. for about 120 seconds to activate the wiring. The surface of the substrate 8 is selectively electrolessly plated, and then the surface of the substrate W is cleaned with a cleaning liquid such as pure water. As a result, the wiring protection film 9 made of a Co-WP alloy film is selectively formed on the exposed surface of the wiring 8 to protect the wiring 8.
[0007]
[Problems to be solved by the invention]
By the way, when forming a wiring protection film made of a Co-WP alloy film by electroless plating, as described above, pretreatment, plating and post-treatment with various chemicals, and treatment such as rinsing between them are performed. In these processes, the substrate surface comes into contact with liquids of various conditions. In addition, various materials such as an oxide film, a barrier film, a wiring material, and a catalyst coexist on the substrate surface itself, and various surface states can be assumed if the processing conditions in the previous process are included.
[0008]
In the presence of the diversity on the liquid side and the diversity on the substrate side, a protective film (plating film) is selectively and selectively formed on the bottom and side surfaces of the wiring formed on the surface of the substrate or on the exposed surface. It must be formed in a state where the thickness uniformity in the plane is enhanced, and satisfy the desired requirements of improving the reliability of wiring.
[0009]
For this purpose, it is necessary not only to optimize the respective processes but also to optimize the processes before and after, and to assemble the process and the apparatus so that the conditions can be maintained reliably. In the past, however, the mere provision of a plating film to improve reliability, or the conditions of plating solutions for that purpose, had been studied. At the present time, no proposal has been made regarding the operation of.
[0010]
The present invention has been made in view of the above circumstances, and has a reproducibility within a substrate surface of a semiconductor wafer or the like and between substrates, and enables a semiconductor device or the like to be manufactured with a high yield and a substrate processing apparatus. The purpose is to provide.
[0011]
[Means for Solving the Problems]
The invention according to claim 1, when selectively forming a protective film on the bottom surface and the side surface of the embedded wiring formed on the surface of the substrate, or on the exposed surface, performing a plating pretreatment on the substrate, A substrate processing method, wherein the surface of the substrate is subjected to electroless plating to selectively form the protective film on the bottom and side surfaces of the wiring or on the exposed surface, and the processed substrate is dried. is there.
[0012]
As a result, a series of processes for forming a protective film by electroless plating on the bottom and side surfaces of the embedded wiring formed on the surface of the substrate or on the exposed surface can be continuously performed, and the substrate is finished to a dry state. In addition, not only can it be transported to the next step as it is, but also the deterioration of the protective film (plating film) before the next step can be suppressed.
[0013]
According to a second aspect of the present invention, there is provided the substrate processing method according to the first aspect, wherein the substrate to be subjected to the plating pretreatment is supplied in a dry state.
The invention according to claim 3 is characterized in that the substrate after the electroless plating is subjected to a post-treatment for improving the selectivity of the protective film, and thereafter, the substrate is dried. 3. The substrate processing method according to 1 or 2. Thereby, the selectivity of the protective film (plating film) can be improved and the yield can be increased.
[0014]
According to a fourth aspect of the present invention, in the plating pretreatment, a step of cleaning the surface of the substrate, and applying a catalyst to the surface of the substrate to be plated on the substrate after the cleaning to activate the surface of the substrate to be plated 4. The substrate processing method according to claim 1, further comprising:
In general, the result of electroless plating largely depends on the state of the base. The surface of the substrate varies depending on the conditions of the previous process, such as an oxide film being formed on the wiring film, a metal component remaining on the interlayer insulating film, or an anticorrosive being strongly adsorbed. For this reason, by performing appropriate cleaning and activation treatments as plating pretreatment, it is necessary to clean the entire substrate surface and initialize and activate the base surface to be plated, thereby performing reproducible plating. Can be.
[0015]
In the invention according to claim 5, when selectively forming the protective film on the exposed surface of the wiring, prior to the step of cleaning the substrate surface, oxidation of the wiring metal by an oxidizing agent and mechanical polishing by an abrasive are performed. Either chemical mechanical polishing to planarize by removal, electrochemical polishing to planarize by anodic oxidation and special electrolyte, or combined electrochemical polishing to planarize by anodic oxidation and abrasive grains. 5. The method according to claim 4, wherein the exposed surface is planarized.
[0016]
The invention according to claim 6 is the substrate processing method according to claim 4 or 5, wherein the cleaning of the substrate surface is performed by subjecting the substrate to plasma processing under reduced pressure or normal pressure atmosphere. .
Since the plasma treatment physically treats the surface, it can be cleaned regardless of the type of film present on the substrate surface.
The invention according to claim 7 is the substrate processing method according to any one of claims 4 to 6, wherein the activation treatment of the base surface to be plated is performed by light irradiation, a CVD method, or a PVD method. .
[0017]
The invention according to claim 8, wherein the cleaning treatment of the substrate surface is performed by adding a chelating agent to an inorganic acid having a pH of 2 or less, an acid having a chelating ability of pH 5 or less, or an acid having a pH of 5 or less. By contacting the substrate surface with a chemical solution consisting of an alkaline solution capable of removing an anticorrosive for wiring or an alkaline solution of amino acids, and thereafter, rinsing the cleaned substrate surface with a rinse solution. The substrate processing method according to claim 4, wherein
[0018]
Examples of the inorganic acid having a pH of 2 or less include hydrofluoric acid, sulfuric acid, and hydrochloric acid. Examples of the acid having a chelating ability having a pH of 5 or less include formic acid, acetic acid, oxalic acid, tartaric acid, citric acid, maleic acid and salicylic acid. Examples of the chelating agent to be added to an acid having a pH of 5 or less include halides, carboxylic acids, dicarboxylic acids, oxycarboxylic acids, and water-soluble salts thereof. By performing a cleaning treatment using these, it is possible to remove the CMP residue made of copper or the like remaining on the insulating film and the oxide on the surface of the plating base, thereby improving the plating selectivity and the adhesion to the base. it can. An anticorrosion agent generally used in the CMP process is usually an inhibitor of deposition of a plating film. However, an alkaline solution having an ability to remove the anticorrosion agent attached to the wiring, for example, tetramethylammonium hydroxide (TMAH) is used. By using, such an anticorrosive can be effectively removed. Note that the same effects as those of the above-mentioned acids can be realized by an alkaline solution of an amino acid such as glycine, cysteine, and methionine.
[0019]
The invention according to claim 9 is the substrate processing method according to claim 8, wherein the rinsing liquid is any one of pure water, hydrogen gas-dissolved water, and electrolytic cathode water.
By rinsing the substrate surface with a rinsing liquid after the cleaning, it is possible to prevent the chemical used for the cleaning from remaining on the substrate surface and hindering the next activation step. As the rinsing liquid, ultrapure water is generally used. However, depending on the material composition of the surface of the base to be plated, even if ultrapure water is used, the wiring material may corrode due to a local battery action or the like. In such a case, the rinsing liquid does not contain impurities such as hydrogen gas dissolved water obtained by dissolving hydrogen gas in ultrapure water or electrolytic cathode water obtained by diaphragm-type electrolysis of ultrapure water, and It is desirable to use water with high reducing power. In addition, since the chemical used for cleaning may have some corrosiveness with respect to the wiring material and the like, it is desirable to shorten the time between the cleaning processing and the rinsing processing as much as possible.
[0020]
In the invention according to claim 10, the application of the catalyst to the surface of the substrate to be plated is performed by bringing the surface of the substrate to be plated into contact with a chemical solution containing palladium, and thereafter, the substrate surface after the application of the catalyst is rinsed with a rinsing liquid. The substrate processing method according to any one of claims 4 to 9, wherein a rinsing process is performed.
[0021]
By providing a catalyst to the surface of the base to be plated, the selectivity of electroless plating can be increased. As the catalyst metal, there are various substances, but it is preferable to use palladium in terms of the reaction rate and ease of control. As a method of applying the catalyst, there are a case where the entire substrate is immersed in the catalyst solution and a case where the catalyst solution is sprayed toward the surface of the substrate by spraying or the like. You can choose. In general, when forming a thin film, the spray method is superior in reproducibility and the like. As in the case of the cleaning treatment, if the catalyst solution remains on the substrate surface, there is a possibility that corrosion of the wiring material and the like and the plating process may be adversely affected. Is desirably as short as possible.
[0022]
The invention according to claim 11 is characterized in that the rinsing liquid is pure water, hydrogen gas-dissolved water, electrolytic cathode water, or an aqueous solution of a component constituting a plating solution used for electroless plating. 11. The substrate processing method according to item 10.
As the rinsing liquid, as in the case of the cleaning treatment, any of pure water, hydrogen gas-dissolved water, and electrolytic cathode water can be used, but in order to familiarize the substrate prior to the next plating step. For example, it is also possible to use an aqueous solution of a component constituting the electroless plating solution such as a reducing agent.
[0023]
According to a twelfth aspect of the present invention, when the catalyst is applied to the surface of the base to be plated, the concentration of the palladium catalyst on the surface of the base to be plated after the catalyst is applied is 1 cm. ² 12. The substrate processing method according to claim 4, wherein the amount is 0.4 to 8 μg per unit.
In order to form a uniform and continuous electroless plating film over the entire substrate, the amount of catalyst applied to the surface of the underlying substrate to be plated must be more than a certain level. ² It has been experimentally confirmed by the present inventors that this requirement can be satisfied if at least 0.4 μg of palladium is provided per palladium. Also, it is known that when a certain amount of palladium is applied, corrosion of the underlayer occurs, and the resistance value of the entire wiring is increased. ² It has been experimentally confirmed by the inventors that such a tendency becomes remarkable when 8 μg or more of palladium is applied per unit.
[0024]
The invention according to claim 13 is characterized in that the amount of the chemical solution used for the pretreatment is measured, the composition in the pretreatment solution is analyzed, and the insufficient components in the pretreatment solution are replenished. A substrate processing method according to any one of claims 4 to 12.
Since palladium solutions and the like are relatively expensive, it is conceivable to recycle these pretreatment solutions.In such a case, however, the concentration of each component must be controlled since the effective components decrease with the treatment. preferable.
[0025]
The invention according to claim 14 is the substrate processing method according to any one of claims 1 to 13, wherein a deposition rate of the protective film by the electroless plating is set to 10 to 200 ° / min. .
The plating rate is directly linked to productivity and cannot be reduced too much. On the other hand, if it is too fast, uniformity and reproducibility cannot be secured. In general, a film thickness of about several tens to several hundreds of degrees is required for the protective film for protecting the wiring. In this case, it is desirable to set the film formation rate to 10 to 200 degrees per minute. The plating rate can be controlled by both the plating solution composition conditions such as pH and the reaction conditions such as reaction temperature.
[0026]
The invention according to claim 15 is characterized in that the formation of the protective film by the electroless plating is performed by bringing the substrate into contact with a plating solution having a pH of 7 to 10, containing an alkali metal, and containing no ammonia. The substrate processing method according to any one of claims 1 to 14, wherein the method is performed.
[0027]
Generally, in electroless plating, the plating solution is heated to control the reaction.If ammonium ions are contained in the heated plating solution, ammonia is likely to volatilize, so that the plating solution composition must be maintained stably. Becomes difficult. Therefore, it is difficult to maintain the reproducibility of the plating rate, the composition of the plating film, and the like for a long period of time. Such an adverse effect can be prevented by using an alkali metal salt instead of an ammonium salt as a component of the plating solution so that ammonium ions are not contained in the plating solution.
[0028]
The invention according to claim 16 is the substrate processing method according to claim 15, wherein the plating solution contains tungsten at a concentration of at least 1.5 g / l or more.
Among the nickel alloys and cobalt alloys, those which realize the above-mentioned protective effect are desired to contain a certain amount of tungsten in the alloy film. For this purpose, a certain amount or more of tungsten must be contained in the electroless plating solution. By setting the amount to at least 1.5 g / l or more, the amount of tungsten in the alloy is effectively controlled. be able to.
[0029]
The invention according to claim 17 is the substrate processing method according to any one of claims 1 to 16, wherein the protective film is an alloy film containing three elements of cobalt, tungsten, and phosphorus.
Among nickel alloys or cobalt alloys, alloy films containing the three elements of cobalt, tungsten, and phosphorus are advantageous in forming thin films because the film formation rate is relatively slow, and the plating solution is relatively stable and the film composition is controlled. Is not only easy, but also its reproducibility can be easily ensured.
[0030]
The invention according to claim 18 is characterized in that the average composition of the alloy film is in a range of 75 to 90 atm% of cobalt, 1 to 10 atm% of tungsten, and 5 to 25 atm% of phosphorus. Is the way.
In the composition of an alloy film containing three elements of cobalt, tungsten, and phosphorus, there is a trade-off relationship between the contents of tungsten and phosphorus, and the plating rate is extremely reduced as the amount of tungsten increases. Therefore, the minimum tungsten composition for realizing the protective effect is 1 atm% or more, and the maximum composition from the viewpoint of plating rate is 10 atm% or less. Accordingly, the phosphorus composition is 5 to 25 atm% and the cobalt composition is 75 to 90 atm. %.
[0031]
The invention according to claim 19 is characterized in that the amount of the plating solution is measured, the composition of the plating solution is analyzed, and the insufficient component in the plating solution is supplied. Or a substrate processing method described in
Each component in the plating solution is consumed by the film formation, and separately, the reducing agent decomposes with time. In addition, since the plating solution is heated and used, a composition change occurs due to evaporation of moisture and the like. Further, some liquid is taken out of the system during the treatment. Therefore, by analyzing the pH and the composition of each component in the plating solution and maintaining them in a certain range, the reproducibility of the film composition can be maintained.
[0032]
The invention according to claim 20 is the substrate processing method according to any one of claims 15 to 19, wherein the dissolved oxygen concentration in the plating solution is measured to control the dissolved oxygen concentration to be constant. is there.
Although the detailed mechanism is not known, according to the experimental results of the inventors, the reproducibility of the plating reaction deteriorates unless the dissolved oxygen in the plating solution falls within a certain range. Therefore, the stability of the plating reaction can be maintained by measuring and controlling the dissolved oxygen concentration in the plating solution.
[0033]
The invention according to claim 21 is that, after the electroless plating treatment, the substrate is pulled up from the plating solution, and a stop solution made of a neutral solution having a pH of 6 to 7.5 is brought into contact with the substrate surface to stop the plating reaction. The substrate processing method according to any one of claims 1 to 20, wherein:
This makes it possible to quickly stop the plating reaction immediately after lifting the substrate from the plating solution, thereby preventing the plating film from being unevenly plated. This processing time is preferably, for example, 1 to 5 seconds.
[0034]
The invention according to claim 22 is the substrate processing method according to claim 21, wherein the stop solution is pure water, hydrogen gas-dissolved water, or electrolytic cathode water.
As described above, depending on the material composition of the surface, the wiring material may be corroded due to local battery action, etc., and in such a case, the plating is stopped with ultrapure water having a reducing property. Adverse effects can be avoided.
[0035]
The invention according to claim 23 is characterized in that the post-processing of the substrate includes rubbing the surface of the cleaning member against the surface to be processed of the substrate while rotating the cylindrical cleaning member around an axis. A substrate processing method according to any one of claims 3 to 22.
Thereby, plating residues such as metal fine particles on the interlayer insulating film can be reliably removed, and the selectivity of electroless plating can be further improved.
[0036]
The invention according to claim 24 is characterized in that the post-processing of the substrate includes flattening the surface to be processed by any one of chemical mechanical polishing, electrochemical polishing or composite electrochemical polishing. A substrate processing method according to any one of claims 3 to 23.
Thereby, plating residues such as metal fine particles on the interlayer insulating film can be reliably removed, and the selectivity of electroless plating can be further improved. Further, since the surface to be plated can be flattened, the processing in the next step becomes easy.
[0037]
The invention according to claim 25 is characterized in that a chemical solution containing one or more of a surfactant, an organic alkali and a chelating agent is used for the post-treatment of the substrate. A substrate processing method according to any one of the above.
By using these chemicals, the selectivity of electroless plating can be more efficiently improved. The surfactant is preferably a nonionic one, the organic alkali is preferably a quaternary ammonium or an amine, and the chelating agent is preferably an organic acid such as ethylenediamine or citric acid.
[0038]
The invention according to claim 26 is characterized in that after the post-treatment of the substrate, the substrate is rinsed with pure water, hydrogen gas-dissolved water or electrolytic cathode water, and then the substrate is dried. The substrate processing method according to any one of the above.
As described above, depending on the material composition of the surface, the wiring material may be corroded due to local battery action or the like, but in such a case, rinsing with ultrapure water having reducing properties can be used. The evil can be avoided.
[0039]
The invention according to claim 27 is characterized in that when performing a drying process for bringing the substrate into a dry state, the humidity of the atmosphere around the substrate is controlled using dry air or a dry inert gas. 27. The substrate processing method according to any one of 1 to 26.
When drying is performed in a normal atmosphere, the moisture on the substrate is scattered in the atmosphere and the humidity increases, and although the drying process is performed, a large amount of moisture is adsorbed on the substrate surface. This may cause new problems such as oxidation of the wiring portion. In addition, problems such as generation of water marks due to mist back in the spin dryer are also assumed. Therefore, such adverse effects can be avoided by controlling the atmospheric humidity during drying using dry air or dry nitrogen.
[0040]
The invention according to claim 28 is the substrate processing method according to any one of claims 1 to 27, wherein the dried substrate is subjected to a heat treatment for modifying the protective film.
Thereby, the barrier property of the protective film (plating film) formed on the exposed surface of the wiring, the adhesion to the wiring, and the like can be improved. Further, by performing a heat treatment before the next step, it is possible to minimize the thermal deformation and the like of the protective film (plating film) formed on the exposed surface of the wiring.
[0041]
The invention according to claim 29 is the substrate processing method according to any one of claims 1 to 28, wherein the temperature of the heat treatment is 120 to 450 ° C.
The temperature required for the modification of the protective film is preferably at least 120 ° C. in consideration of the reality of the processing time and not more than 450 ° C. in consideration of the heat resistance of the material constituting the device. .
[0042]
The invention according to claim 30 is the substrate processing method according to any one of claims 1 to 29, wherein the thickness of the protective film formed on the surface of the base to be plated is measured.
This measures the thickness of the protective film formed on the exposed surface of the wiring, and adjusts the processing time of the plating process on the next substrate, for example, according to the change in the film thickness, thereby forming the film on the exposed surface of the wiring. The thickness of the protective film to be formed can be controlled to be constant.
[0043]
An invention according to claim 31 is a substrate processing apparatus for selectively forming a protective film on the bottom surface and side surface of an embedded wiring formed on a surface of a substrate or on an exposed surface, wherein a pre-plating treatment is performed on the substrate surface. A pretreatment unit, an electroless plating unit for applying electroless plating to the surface of the substrate after the pretreatment, and selectively forming the protective film on the bottom and side surfaces of the wiring or on the exposed surface; and the electroless plating. A substrate processing apparatus comprising a drying unit for drying a processed substrate.
As a result, a series of processes for forming a protective film on the bottom and side surfaces of the embedded wiring formed on the surface of the substrate or the exposed surface by electroless plating can be continuously performed in one apparatus, and furthermore, in a dry state. Since the substrate is finished up to that point, it can be transported to the next process as it is.
[0044]
The invention according to claim 32 is characterized in that a post-processing unit is provided between the electroless plating unit and the drying unit for performing a post-processing for improving the selectivity of the protective film formed on the substrate surface. A substrate processing apparatus according to claim 31.
This makes the whole process more compact than when each processing step is performed by a separate apparatus (processing section), does not require a large installation space, can reduce the initial cost and running cost of the apparatus, and can shorten the processing time. A protective film (plating film) with enhanced selectivity can be formed in a short time.
[0045]
The invention according to claim 33, wherein the pretreatment unit is used for treating the substrate surface with a chemical solution, removing the chemical solution from the substrate surface, applying a catalyst to the substrate surface, and applying the catalyst. 33. The substrate processing apparatus according to claim 31, further comprising a second pretreatment unit that removes the removed chemical solution from the substrate surface.
The surface condition of the substrate put into the processing apparatus depends on the pre-process, but the surface cleaning and initialization by appropriate chemical treatment in the first pre-processing unit and the activity by the application of catalyst in the second pre-processing unit By performing the chemical treatment, the plating treatment can be performed without depending on the previous process.
[0046]
The substrate processing apparatus according to any one of claims 31 to 33, wherein the pretreatment unit is configured to spray a chemical solution onto the substrate by spraying. It is.
A dipping method and a spraying method can be considered as a method for applying the catalyst, but the spraying method is superior in terms of reliability and the like.
[0047]
According to a thirty-fifth aspect of the present invention, the pre-treatment unit measures the amount of the pre-treatment solution held by the pre-treatment unit, analyzes the composition of the pre-treatment solution, and replenishes the insufficient components in the pre-treatment solution. The substrate processing apparatus according to any one of claims 31 to 34, further comprising a liquid management unit.
Methods for analyzing the composition of the pretreatment liquid include electrode method, titration method, electrochemical measurement, etc. The thin film plating can be realized with good reproducibility by controlling the amount and composition of the pretreatment liquid by replenishing the pretreatment liquid storage tank.
[0048]
In the invention according to claim 36, the electroless plating unit includes a plating tank, a plating solution circulation system and a plating solution storage tank, and the plating solution circulation system can be individually set at the time of plating standby and at the time of plating treatment. The plating solution can be circulated between the plating tank and the plating solution storage tank at a flow rate, and the circulation flow rate of the plating solution during the plating standby is 2 to 20 L / min, and the circulation flow rate of the plating solution during the plating process is zero. The substrate processing apparatus according to any one of claims 31 to 35, wherein the rate is 10 L / min to 10 L / min.
As a result, a large circulation flow rate of the plating solution is secured during the standby time of the plating, and the temperature of the plating bath in the cell is maintained at a constant temperature. A protective film (plating film) can be formed.
[0049]
The invention according to claim 37, wherein the plating solution management unit that measures the amount of the plating solution held by the electroless plating unit, analyzes the composition in the plating solution, and replenishes the insufficient components in the plating solution. The substrate processing apparatus according to any one of claims 31 to 36, comprising:
Methods for analyzing the composition of the plating solution include absorption spectrophotometry, titration, electrochemical measurement, and electrophoresis.The results of these analyzes are processed by signal processing to determine the insufficient components in the plating solution from the replenishment tank. By supplying the plating solution to the plating solution storage tank using a pump or the like and thereby controlling the amount and composition of the plating solution, thin film plating can be realized with good reproducibility.
[0050]
The invention according to claim 38, wherein the plating solution management unit has a dissolved oxygen concentration meter for measuring dissolved oxygen in the plating solution held by the electroless plating unit, and the plating solution is instructed by the dissolved oxygen concentration meter. 38. The substrate processing apparatus according to claim 37, wherein the concentration of dissolved oxygen is controlled to be constant.
As a method for measuring the dissolved oxygen concentration in the plating solution, there are electrochemical methods and the like, and by controlling the dissolved oxygen concentration in the plating solution to a constant value by degassing, blowing nitrogen, or the like, the plating reaction can be performed with good reproducibility. Can be realized.
[0051]
The invention according to claim 39, wherein the post-processing unit uses at least one of a roll scrub cleaning method, a pencil cleaning method, and an etching back method using an etching solution. 38. A substrate processing apparatus according to any one of 38.
Thus, by applying a physical force to the substrate surface after the plating process, or by contacting a chemical solution having an etching force, the residue on the interlayer insulating film is completely removed, and the yield of the semiconductor device and the like is reduced. Can be improved.
[0052]
The invention according to claim 40 is characterized in that the post-processing unit uses at least one of a chemical mechanical polishing unit, an electrochemical polishing unit, and a composite electrochemical polishing unit. 40. A substrate processing apparatus according to any one of Items 31 to 39.
Thus, by applying a physical force to the substrate surface after the plating process, the residue on the interlayer insulating film can be completely removed, and the yield of semiconductor devices and the like can be improved. Further, the surface of the substrate after the plating process can be flattened, and the subsequent substrate processing becomes easy.
[0053]
The invention according to claim 41 is the substrate processing apparatus according to any one of claims 31 to 40, wherein the drying unit comprises a spin dryer.
As a result, the substrate after the post-processing can be dried quickly, so that the productivity of the apparatus can be increased.
[0054]
The invention according to claim 42, wherein the drying unit has a dry air unit for supplying dry air to the drying unit or a dry inert gas unit for supplying dry inert gas to the drying unit. A substrate processing apparatus according to any one of the above.
This makes it possible to thoroughly dry the substrate after the post-processing, and to avoid problems such as oxidation of the wiring portion due to adsorbed moisture and generation of water marks due to mist back.
[0055]
43. The substrate according to claim 31, further comprising a heat treatment unit for performing a heat treatment for modifying the protective film on the substrate dried by the drying unit. Processing device.
As a result, a series of steps up to the improvement of the barrier property of the protective film formed on the surface wiring to be plated on the surface of the substrate and the adhesion to the wiring can be efficiently realized by one apparatus.
[0056]
The invention according to claim 44, further comprising a film thickness measuring unit for measuring the film thickness of the protective film formed on the surface of the base to be plated, wherein the substrate processing apparatus according to any one of claims 31 to 43, It is.
As the film thickness measuring unit, there are an optical type, an AFM, an EDX, and the like. By processing the signal, for example, the processing time of the plating process for the next substrate can be adjusted. The thickness of the protective film formed on the surface of the base to be plated can be controlled to be constant.
[0057]
The invention according to claim 45 is characterized by having a device for dissolving hydrogen gas in ultrapure water or a device for electrolyzing ultrapure water, which supplies hydrogen gas-dissolved water or electrolytic cathode water to each unit. A substrate processing apparatus according to any one of claims 31 to 44.
[0058]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a plan layout view of the substrate processing apparatus according to the embodiment of the present invention. As shown in FIG. 1, the substrate processing apparatus includes a substrate cassette 10 containing a substrate W (see FIG. 1, the same applies hereinafter) in which a wiring 8 made of copper or the like is formed in a wiring recess 4 formed on the surface. And a loading / unloading unit 12 for placing and housing the. Then, at a position along one long side of the rectangular housing 16 provided with the exhaust system, a pre-plating treatment of the substrate W, that is, a first pre-treatment unit 18 for cleaning the surface of the substrate W, A second pretreatment unit 20 for applying a catalyst to the exposed surface of the wiring 8 to activate the same, an electroless plating unit 22 for performing electroless plating on the surface of the substrate W (the surface to be processed), and wiring by the electroless plating. A post-processing unit 24 for performing post-processing of the substrate W for improving the selectivity of the protective film 9 (see FIG. 1, the same applies hereinafter) formed on the surface of the substrate 8 is arranged in series.
[0059]
Further, at a position along the other long side of the housing 16, a drying unit 26 for drying the post-processed substrate W, a heat treatment unit 28 for performing heat treatment (annealing) on the dried substrate W, and a surface of the wiring 8. A film thickness measuring unit 30 for measuring the film thickness of the formed protective film 9 is arranged in series. Further, a transfer robot 34 that can freely move along the rail 32 in parallel with the long side of the housing 16 and transfers substrates between these units and the substrate cassette 10 mounted on the load / unload unit 12 is provided. , Are arranged at positions sandwiched between the units arranged linearly.
[0060]
Next, a series of electroless plating processes performed by the substrate processing apparatus will be described with reference to FIG. In this example, as shown in FIG. 1, a case will be described in which a wiring protection film (cover material) 9 made of a Co—WP alloy film is selectively formed to protect the wiring 8.
[0061]
First, one substrate W is loaded from the substrate cassette 10 mounted on the load / unload unit 12 by storing the substrate W having the wiring 8 formed on the surface and drying the substrate W with the surface of the substrate W facing upward (face-up). It is taken out by the transfer robot 34 and transferred to the first pretreatment unit 18. In the first pretreatment unit 18, the substrate W is held face down, and a cleaning process (chemical solution cleaning) is performed on the surface of the substrate W as a plating pretreatment. That is, for example, when the liquid temperature is 25 ° C. and the dilution H ₂ SO ₄ Is sprayed toward the surface of the substrate W to remove CMP residues such as copper remaining on the surface of the insulating film 2 (see FIG. 1) and oxides on the wiring film. Rinse (clean) the cleaning easy liquid remaining on the surface with a rinsing liquid such as pure water.
[0062]
Chemicals used here include inorganic acids such as hydrofluoric acid, sulfuric acid and hydrochloric acid having a pH of 2 or less, and acids having a chelating ability of pH 5 or less such as formic acid, acetic acid, oxalic acid, tartaric acid, citric acid, maleic acid and salicylic acid. And an acid having a pH of 5 or less to which a chelating agent such as a halide, a carboxylic acid, a dicarboxylic acid, an oxycarboxylic acid, or a water-soluble salt thereof is added. By performing a cleaning treatment using these chemicals, the CMP residue composed of copper or the like remaining on the insulating film and the oxide on the surface of the plating base are removed, and the selectivity of the plating and the adhesion to the base are improved. be able to. An anticorrosion agent generally used in the CMP process is usually an inhibitor of the deposition of the plating film. However, an alkali chemical having an ability to remove the anticorrosion agent attached to the wiring, for example, tetramethylammonium hydroxide (TMAH) is used. By using, such an anticorrosive can be effectively removed. Note that the same effects as those of the above-mentioned acids can be realized by an alkaline solution of an amino acid such as glycine, cysteine, and methionine.
[0063]
By rinsing (cleaning) the surface of the substrate W with a rinsing liquid after cleaning, it is possible to prevent the chemical used for cleaning from remaining on the surface of the substrate W and hinder the next activation step. As this rinsing liquid that can be prevented, ultrapure water is generally used, but depending on the material composition of the surface of the base to be plated, even if ultrapure water is used, the wiring material corrodes due to local battery action and the like. Sometimes. In such a case, the rinsing liquid does not contain impurities such as hydrogen gas dissolved water obtained by dissolving hydrogen gas in ultrapure water or electrolytic cathode water obtained by diaphragm-type electrolysis of ultrapure water, and It is desirable to use water with high reducing power. Further, since the chemical used for the cleaning treatment may have some corrosiveness to the wiring material and the like, the time between the cleaning treatment and the rinsing treatment is preferably as short as possible.
[0064]
In this example, an example is shown in which the surface of the wiring 8 is cleaned (pre-plating) using a chemical solution, but the cleaning of the surface of the wiring 8 is performed under reduced pressure or normal pressure. The plasma treatment may be performed on the substrate in an atmosphere.
[0065]
Next, the substrate W after the cleaning process and the rinsing process is transported to the second pre-processing unit 20 by the transport robot 34, where the substrate W is held face down, and a catalyst application process is performed on the surface. That is, for example, when the liquid temperature is 25 ° C. and PdCl ₂ / HCl is sprayed toward the surface of the substrate W, thereby causing Pd as a catalyst to adhere to the surface of the wiring 8, that is, forming a Pd nucleus as a catalyst nucleus (seed) on the surface of the wiring 8. Then, the exposed surface of the surface wiring of the wiring 8 is activated, and thereafter, the catalyst solution remaining on the surface of the substrate W is rinsed (cleaned) with a rinsing liquid such as pure water.
[0066]
As this chemical solution (catalyst chemical solution), an inorganic or organic acid solution containing Pd is used. If the Pd content in the catalyst solution is too small, the catalyst density on the surface of the base to be plated becomes low, and plating cannot be performed. If too long, a defect such as pitching is caused on the wiring 8.
[0067]
In order to form a uniform and continuous electroless plating film over the entire substrate, the amount of catalyst applied to the surface of the underlying substrate to be plated must be more than a certain level. ² It has been experimentally confirmed that this requirement can be met if palladium is applied in an amount of 0.4 μg or more. Further, it is known that when Pd is applied over a certain amount, erosion of the base proceeds, and the resistance value of the base increases. Base surface 1cm ² It has been experimentally confirmed that such a tendency becomes remarkable when palladium is applied in an amount of 8 μg or more.
[0068]
As described above, by applying the catalyst to the surface of the substrate W, the selectivity of the electroless plating can be improved. Here, there are various substances as the catalyst metal, but Pd is preferably used in view of the reaction rate and the ease of control. As a method of applying the catalyst, there are a case where the entire substrate is immersed in the catalyst solution and a case where the catalyst solution is sprayed toward the surface of the substrate by spraying or the like. You can choose. In general, when forming a thin film, the spray method is superior in reproducibility and the like.
[0069]
Since a palladium solution or the like is relatively expensive, it is conceivable to use these pretreatment liquids in a circulating manner. Since the processing liquid is taken out, it is preferable to control the concentration and amount of each component.
For this reason, it is preferable to provide a pretreatment liquid management unit (not shown) for analyzing the composition of the pretreatment liquid and adding a shortage. Specifically, since the chemical used for cleaning is mainly composed of an acid or an alkali, the pH is measured, for example, and a decrease is supplied from a difference from a predetermined value. Can supply the reduced amount. For the catalyst solution, for example, in the case of an acidic palladium solution, the amount of acid can be measured by pH, and the amount of palladium can be measured by titration or turbidimetry, and a reduced amount can be supplied in the same manner. .
[0070]
Further, in order to improve the selectivity, it is necessary to remove residual Pd on the interlayer insulating film 2 and the wiring 8, and a pure water rinse is generally used. As in the case of the cleaning treatment, if the catalyst solution remains on the substrate surface, there is a possibility that corrosion of the wiring material and the like and the plating process may be adversely affected. Is desirably as short as possible. As the rinsing liquid, as in the case of the cleaning treatment, any of pure water, hydrogen gas-dissolved water, and electrolytic cathode water can be used, but in order to familiarize the substrate prior to the next plating step. Alternatively, an aqueous solution of a component constituting the electroless plating solution can be used.
[0071]
Although this example shows an example in which the activation process based on the adhesion of Pd on the surface of the wiring 8 is performed by using a chemical solution, the activation process is performed by light irradiation, a CVD method, or a PVD method. It may be.
[0072]
Then, the substrate W provided with the catalyst and rinsed is transferred to the electroless plating unit 22 by the transfer robot 34, where the substrate W is held face down, and the surface is subjected to electroless plating. That is, for example, the substrate W is immersed in, for example, about 120 seconds in a Co-WP plating solution having a liquid temperature of 80 ° C., and selectively electroless plating (electroless Co (WP lid plating) to selectively form the wiring protective film (lid material) 9. The composition of the plating solution is, for example, as follows.
[0073]
・ CoSO ₄ ・ 7H ₂ O: 14 g / L
・ Na ₃ C ₆ H ₅ O ₇ ・ 2H ₂ O: 70 g / L
・ H ₃ BO ₃ ： 40g / L
・ Na ₂ WO ₄ ・ 2H ₂ O: 12 g / L
・ NaH ₂ PO ₂ ・ H ₂ O: 21 g / L
-PH: 9.5
[0074]
Here, it is preferable to use a plating solution having a pH of 7 to 10, containing a sodium element, and not containing an ammonium ion. Generally, in electroless plating, the plating solution is heated to control the reaction.If ammonium ions are contained in the heated plating solution, ammonia is likely to volatilize, so that the plating solution composition must be maintained stably. Becomes difficult. Therefore, it is difficult to maintain the reproducibility of the plating rate, the composition of the plating film, and the like for a long period of time. Such an adverse effect can be prevented by using, for example, an alkali metal salt instead of an ammonium salt as a component of the plating solution so that ammonium ions are not contained in the plating solution.
[0075]
Here, it is preferable that the deposition rate of the protective film 9 by electroless plating is 10 to 200 ° per minute. The plating rate is directly linked to productivity and cannot be reduced too much. On the other hand, if it is too fast, uniformity and reproducibility cannot be secured. In general, the protective film 9 is often required to have a film thickness of about several tens to several hundreds of degrees. The plating rate can be controlled by both the plating solution composition conditions such as pH and the reaction conditions such as reaction temperature.
[0076]
It is preferable to use a plating solution whose composition contains W at a concentration of at least 1.5 g / l or more. Among Ni alloys or Co alloys, those that realize the function as the protective film 9 are desired to contain a certain amount of W in the alloy film. For this purpose, the plating solution must contain a certain amount or more of W, but by controlling the amount to at least 1.5 g / l, it is necessary to effectively control the amount of W in the alloy. Can be.
[0077]
Here, each component in the plating solution is consumed by the film formation, and the reducing agent in the plating solution decomposes with time. In addition, since the plating solution is heated and used, a composition change occurs due to evaporation of moisture and the like. For this reason, it is preferable to measure the amount of the plating solution, analyze the pH of the plating solution and the composition of each component in the plating solution, and maintain a certain range by replenishing the insufficient components in the plating solution, Thereby, reproducibility of the film composition can be maintained.
[0078]
Although the detailed mechanism is not known, according to the results of the experiment, the reproducibility of the plating reaction deteriorates unless the dissolved oxygen in the plating solution falls within a certain range. For this reason, it is preferable to measure the dissolved oxygen concentration in the plating solution and control the dissolved oxygen concentration to be constant, whereby the stability of the plating reaction can be maintained.
[0079]
A plating solution management unit (not shown) equipped with an analytical instrument and a plating component replenishment mechanism necessary for managing the plating solution as described above can also be provided.
When the pretreatment solution or the plating solution is repeatedly used, certain components are accumulated due to carry-in from outside or decomposition of the plating solution itself, which may lead to reproducibility of plating and deterioration of film quality. By adding a mechanism for selectively removing such a specific component, it is possible to extend the liquid life and improve reproducibility.
[0080]
Note that, as in this example, it is preferable that the protective film 9 be formed of an alloy film containing three elements of Co, W, and P. This is because, among Ni alloys or Co alloys, alloy films containing the three elements of Co, W and P are advantageous in forming a thin film since the film formation rate is relatively slow, and the plating solution is relatively difficult. In addition to being stable and easy to control the film composition, reproducibility can be easily ensured.
[0081]
As described above, when the protective film 9 is composed of an alloy film containing three elements of Co, W and P, the average composition of the protective film (alloy film) 9 is Co: 75 to 90 atm%, W: 1 to 1 10 atm%, P: preferably in the range of 5 to 25 atm%. In the composition of the alloy film containing three elements of Co, W and P, there is a trade-off relationship between the contents of W and P, and when the amount of W increases, the plating rate decreases extremely. Therefore, the minimum W composition for realizing the protective effect is 1 atm% or more, and the maximum composition from the viewpoint of plating rate is 10 atm% or less. Accordingly, the P composition is 5 to 25 atm% and the Co composition is 75 to 90 atm. %.
[0082]
Then, after lifting the substrate W from the plating solution, a stop solution made of a neutral solution having a pH of 6 to 7.5 is brought into contact with the surface of the substrate W to stop the electroless plating process. This makes it possible to stop the plating reaction immediately after the substrate W is pulled up from the plating solution, thereby preventing the plating film from being unevenly plated. This processing time is preferably, for example, 1 to 5 seconds. Examples of the stop solution include pure water, hydrogen gas-dissolved water, and electrolytic cathode water. As described above, depending on the material composition of the surface, the wiring material may be corroded due to local battery action, etc., and in such a case, the plating is stopped with ultrapure water having a reducing property. Adverse effects can be avoided.
Thereafter, the plating solution remaining on the surface of the substrate is rinsed (cleaned) with a rinse solution such as pure water. Thus, the wiring protection film 9 made of a Co-WP alloy film is selectively formed on the surface of the wiring 8 to protect the wiring 8.
[0083]
Next, the substrate W after the electroless plating is transported to the post-processing unit 24 by the transport robot 34, where the selectivity of the protective film (plating film) 9 formed on the surface of the substrate W is improved. Substrate post-processing is performed to increase the yield. In other words, a chemical solution containing one or more of a surfactant, an organic alkali, and a chelating agent is applied to the surface of the substrate W while applying physical force such as roll scrub cleaning or pencil cleaning to the surface of the substrate W. By this, the plating residue such as metal fine particles on the interlayer insulating film 2 is completely removed, and the selectivity of plating is improved. By using these chemicals, the selectivity of electroless plating can be more efficiently improved. The surfactant is preferably a nonionic one, the organic alkali is preferably a quaternary ammonium or an amine, and the chelating agent is preferably an ethylenediamine.
[0084]
When the chemical solution is used as described above, the chemical solution remaining on the surface of the substrate W is rinsed (cleaned) with a rinse solution such as pure water. Examples of the rinsing liquid include pure water, hydrogen gas-dissolved water, and electrolytic cathode water. As described above, depending on the material composition of the surface, the wiring material may be corroded due to local battery action or the like, but in such a case, rinsing with ultrapure water having reducing properties can be used. The evil can be avoided.
[0085]
In addition to the above-described cleaning using physical force such as roll scrub cleaning or pencil cleaning, cleaning using a complexing agent, uniform etching back using an etchant, and the like, and any combination of these may be used for interlayer insulation. The residue on the film may be completely removed.
[0086]
Then, the substrate W after the post-processing is transported to the drying unit 26 by the transport robot 34, where a rinsing process is performed as necessary. Thereafter, the substrate W is rotated at a high speed and spin-dried.
[0087]
Thus, a series of processes for forming the protective film 9 on the exposed surface of the embedded wiring 8 formed on the surface of the substrate W by electroless plating can be continuously performed, and the substrate is finished to a dry state. Not only can it be transported to the next step, but also the deterioration of the protective film (plating film) 9 before the next step can be suppressed.
[0088]
When performing the drying process (spin drying) for bringing the substrate W into a dry state, it is preferable to control the humidity of the atmosphere around the substrate by using dry air or dry inert gas. When drying is performed in a normal atmosphere, moisture on the substrate is scattered in the atmosphere and the humidity increases, and although the drying process is performed, a large amount of moisture is adsorbed on the substrate surface. The moisture may cause new problems such as oxidation of the wiring portion. In addition, problems such as generation of water marks due to mist back in the spin dryer are also assumed. Therefore, such adverse effects can be avoided by controlling the atmospheric humidity during drying using dry air or dry nitrogen.
[0089]
The substrate W after the spin drying is transferred by the transfer robot 34 to the heat treatment unit 28, where the post-processed substrate W is subjected to a heat treatment (annealing) for modifying the protective film 9. The temperature required for reforming the protective film 9 is at least 120 ° C. in consideration of the reality of the processing time, and may not exceed 450 ° C. in consideration of the heat resistance of the material constituting the device. desirable. For this reason, the temperature of this heat treatment (annealing) is, for example, 120 to 450 ° C. By performing the heat treatment on the substrate W in this manner, the barrier property of the protective film (plating film) formed on the exposed surface of the wiring and the adhesion to the wiring can be improved.
[0090]
Next, the substrate W after the heat treatment is transported by the transport robot 34 to a film thickness measuring unit 30 of, for example, an optical type, AFM, EDX, etc., and the wiring protective film formed on the surface of the wiring 8 by the film thickness measuring unit 30. 9 is measured, and the substrate W after the film thickness measurement is returned to the substrate cassette 10 mounted on the load / unload unit 12 by the transfer robot 34.
[0091]
Then, the measurement result of off-line measurement of the thickness of the protective film 9 formed on the exposed surface of the wiring 8 is fed back before the electroless plating treatment, whereby, according to the variation of this film thickness, for example, The processing time of the plating process for the substrate is adjusted. As described above, the film thickness of the protective film 9 formed on the exposed surface of the wiring 8 is measured, and for example, the processing time of the plating process for the next substrate is adjusted in accordance with the change in the film thickness, so that the wiring 8 The thickness of the protective film 9 formed on the exposed surface can be controlled to be constant.
[0092]
When selectively forming the protective film 9 on the exposed surface of the wiring 8, prior to the step of cleaning the exposed surface of the wiring 8, one of chemical mechanical polishing, electrochemical polishing, and composite electrochemical polishing is performed. Thus, the exposed surface of the wiring 8 is preferably flattened, whereby the protective film 9 can be further flattened.
[0093]
Next, details of various units provided in the substrate processing apparatus shown in FIG. 2 will be described below.
The first pre-processing unit 18 and the second pre-processing unit 20 are of the same configuration and adopt a two-liquid separation method of preventing mixing of different liquids, except that the processing liquids (chemical liquids) used are different. The peripheral edge of the lower surface, which is the processing surface (front surface) of the substrate W conveyed by the above, is sealed, and the rear surface side is pressed to fix the substrate W.
[0094]
As shown in FIGS. 4 to 7, the processing units 18 and 20 include a fixed frame 52 attached to an upper portion of a frame 50, and a moving frame 54 that moves up and down relatively to the fixed frame 52. A processing head 60 having a cylindrical housing part 56 having a bottom and opened downward and a substrate holder 58 is suspended and supported by the moving frame 54. That is, the head rotating servomotor 62 is attached to the moving frame 54, and the housing 56 of the processing head 60 is connected to the lower end of the output shaft (hollow shaft) 64 extending below the servomotor 62.
[0095]
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 a lower end of the vertical shaft 68. The substrate holder 58 of the processing head 60 is connected through the intermediary of the processing head 60. The substrate holder 58 is located inside the housing portion 56. The upper end of the vertical shaft 68 is connected via a bearing 72 and a bracket to a fixed ring elevating cylinder 74 fixed to the moving frame 54. Thus, the vertical shaft 68 moves up and down independently of the output shaft 64 with the operation of the lifting cylinder 74.
[0096]
A linear guide 76 is attached to the fixed frame 52 and extends vertically to guide the moving frame 54 up and down. The moving frame 54 is moved along with the operation of a head elevating cylinder (not shown). The ascending and descending is carried out by using 76 as a guide.
[0097]
On the peripheral wall of the housing portion 56 of the processing head 60, a substrate insertion window 56a into which the substrate W is inserted is provided. As shown in FIGS. 8 and 9, a peripheral portion is sandwiched between a main frame 80 made of, for example, PEEK and a guide frame 82 made of, for example, polyethylene, under the housing portion 56 of the processing head 60. A seal ring 84a is provided. The seal ring 84a comes into contact with the peripheral portion of the lower surface of the substrate W and seals the peripheral portion.
[0098]
On the other hand, a substrate fixing ring 86 is fixed to the peripheral edge of the lower surface of the substrate holder 58, and a cylindrical pusher 90 is pressed by the elastic force of a spring 88 disposed inside the substrate fixing ring 86 of the substrate holder 58. It projects downward from the lower surface of the fixing ring 86. Further, between the upper surface of the substrate holder 58 and the upper wall portion of the housing portion 56, a bendable cylindrical bellows plate 92 made of, for example, Teflon (registered trademark) and bendable, which hermetically seals the inside, is disposed. I have.
[0099]
Thus, the substrate W is inserted into the housing portion 56 through the substrate insertion window 56a with the substrate holder 58 raised. Then, the substrate W is guided by the tapered surface 82a provided on the inner peripheral surface of the guide frame 82, positioned and mounted at a predetermined position on the upper surface of the seal ring 84a. 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. By further lowering the substrate holder 58, the substrate W is pressed downward by the elastic force of the spring 88, whereby the substrate W is pressed against the peripheral portion of the surface (lower surface) of the substrate W by the seal ring 84a, and the substrate W is sealed. Then, the substrate W is held between the housing portion 56 and the substrate holder 58 while being held therebetween.
[0100]
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 inside the output shaft 64 form the spline 66. The housing unit 56 and the substrate holder 58 also rotate integrally.
[0101]
A processing tank 100 having an outer tank 100a and an inner tank 100b which is located below the processing head 60 and has an inner diameter slightly larger than the outer diameter of the processing head 60 and is open upward is provided. A pair of legs 104 attached to the lid 102 is rotatably supported on the outer periphery of the processing tank 100. Further, 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 cylinder 108 for moving the lid. Thereby, with the operation of the lid moving cylinder 108, the lid 102 is configured to move between the processing position covering the upper end opening of the processing tank 100 and the side retract position. . On the surface (upper surface) of the lid 102, a nozzle plate 112 having a large number of injection nozzles 112a for injecting, for example, electrolytic ionized water having a reducing power outward (upward) is provided as described below. I have.
[0102]
Further, as shown in FIG. 10, inside the inner tank 100 b of the processing tank 100, a plurality of injection nozzles 124 a for injecting the chemical supplied from the chemical tank 120 along with the driving of the chemical pump 122 upward are formed. The nozzle plate 124 is disposed in a state where the injection nozzles 124a are more evenly distributed over the entire cross section of the inner tank 100b. A drain pipe 126 for discharging a chemical solution (drained liquid) to the outside is connected to the bottom surface of the inner tank 100b. A three-way valve 128 is interposed in the middle of the drain pipe 126, and this chemical solution (drain liquid) is supplied as necessary through a return pipe 130 connected to one outlet port of the three-way valve 128. It can be returned to the tank 120 and reused. Further, in this example, the nozzle plate 112 provided on the surface (upper surface) of the lid 102 is connected to a rinse liquid supply source 132 that supplies a rinse liquid such as pure water. A drain pipe 127 is also connected to the bottom of the outer tub 100a.
[0103]
As a result, the processing head 60 holding the substrate is lowered to cover the opening at the upper end of the processing bath 100 with the processing head 60, and in this state, the nozzle plate disposed inside the inner bath 100b of the processing bath 100 By spraying the chemical toward the substrate W from the injection nozzle 124a of 124, the chemical is uniformly sprayed over the entire lower surface (processed surface) of the substrate W, and while preventing the chemical from scattering outside. Can be discharged from the drain pipe 126 to the outside. Further, the processing head 60 is raised, and the upper end opening of the processing tank 100 is closed with the lid 102, and the nozzle plate 112 is disposed on the upper surface of the lid 102 toward the substrate W held by the processing head 60. By rinsing the rinsing liquid from the injection nozzle 112a, rinsing processing (cleaning processing) of the chemical liquid remaining on the substrate surface is performed, and the rinsing liquid passes between the outer tank 100a and the inner tank 100b, and flows through the drain pipe 127. Since it is discharged through the inner tank 100b, it is prevented from flowing into the inside of the inner tank 100b, so that the rinsing liquid does not mix with the chemical liquid.
[0104]
According to the pre-processing units 18 and 20, the substrate W is inserted and held therein with the processing head 60 raised, as shown in FIG. 4, and thereafter, as shown in FIG. The processing head 60 is lowered to a position covering the upper end opening of the processing tank 100. Then, by rotating the processing head 60 and rotating the substrate W held by the processing head 60, a chemical solution is sprayed toward the substrate W from the spray nozzle 124a of the nozzle plate 124 disposed inside the processing bath 100. The chemical solution is uniformly sprayed over the entire surface of the substrate W. Further, the processing head 60 is raised and stopped at a predetermined position, and the lid 102 at the retreat position is moved to a position covering the upper end opening of the processing tank 100 as shown in FIG. Then, in this state, the rinsing liquid is ejected from the ejection nozzles 112a of the nozzle plate 112 arranged on the upper surface of the lid 102 toward the substrate W held and rotated by the processing head 60. Thereby, the processing of the substrate W with the chemical liquid and the rinsing processing with the rinsing liquid can be performed while the two liquids are not mixed.
[0105]
By adjusting the lowering position of the processing head 60 and adjusting the distance between the substrate W held by the processing head 60 and the nozzle plate 124, the chemical liquid ejected from the ejection nozzle 124 a of the nozzle plate 124 And the injection pressure can be arbitrarily adjusted. Here, when a pretreatment liquid such as a chemical is circulated and used, the effective component decreases with the treatment, and the pretreatment liquid (chemical) is taken out by adhering to the substrate. It is preferable to provide a pretreatment liquid management unit (not shown) for analyzing the water content and adding a shortage. Specifically, since the chemical used for cleaning is mainly composed of an acid or an alkali, the pH is measured, for example, and a decrease is supplied from a difference from a predetermined value. Can supply the reduced amount. For the catalyst solution, for example, in the case of an acidic palladium solution, the amount of acid can be measured by pH, and the amount of palladium can be measured by titration or turbidimetry, and a reduced amount can be supplied in the same manner. .
[0106]
The electroless plating unit 22 is shown in FIGS. The electroless plating unit 22 includes a plating tank 200 (see FIG. 17) and a substrate head 204 that is disposed above the plating tank 200 and detachably holds the substrate W.
[0107]
As shown in detail in FIG. 11, the substrate head 204 has a housing part 230 and a head part 232, and the head part 232 mainly includes a suction head 234 and a substrate receiver 236 surrounding the periphery of the suction head 234. Is configured. A substrate rotation motor 238 and a substrate receiving drive cylinder 240 are housed inside the housing portion 230. The upper end of the output shaft (hollow shaft) 242 of the substrate rotation motor 238 is connected to the rotary joint 244, and the lower end is connected to the rotary joint 244. The rod of the substrate receiving drive cylinder 240 is connected to the suction head 234 of the head 232, and the substrate receiving 236 of the head 232. Further, a stopper 246 for mechanically restricting the elevation of the board receiver 236 is provided inside the housing portion 230.
[0108]
Here, a similar spline structure is employed between the suction head 234 and the substrate receiver 236, and the substrate receiver 236 moves up and down relatively with the suction head 234 with the operation of the substrate receiving drive cylinder 240. When the output shaft 242 is rotated by the driving of the substrate rotation motor 238, the suction head 234 and the substrate receiver 236 are integrally rotated with the rotation of the output shaft 242.
[0109]
As shown in detail in FIGS. 12 to 14, a suction ring 250 for holding the substrate W by suction is attached to a lower peripheral edge portion of the suction head 234 via a press ring 251. The concave portion 250a provided continuously on the lower surface of the suction ring 250 and the vacuum line 252 extending inside the suction head 234 communicate with each other via a communication hole 250b provided in the suction ring 250. Thus, the substrate W is sucked and held by evacuating the concave portion 250a. In this manner, the substrate W is held by being evacuated to a small width (in the radial direction) in a circular shape. By minimizing the effect of the vacuum on the substrate W (such as bending) and immersing the suction ring 250 in a plating solution (processing solution), not only the surface (lower surface) of the substrate W but also the edges It can be immersed in the plating solution. The release of the substrate W is performed by connecting the vacuum line 252 with N ₂ Is supplied.
[0110]
On the other hand, the substrate receiver 236 is formed in a cylindrical shape with a bottom and opened downward, a peripheral wall of which is provided with a substrate insertion window 236a for inserting the substrate W therein, and a disk protruding inward at a lower end. A claw portion 254 is provided. Further, a projection 256 having a tapered surface 256a on the inner peripheral surface serving as a guide for the substrate W is provided on an upper portion of the claw portion 254.
[0111]
Thus, 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 256a of the protruding piece 256, positioned 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 250a of the suction ring 250 is evacuated through the vacuum line 252, thereby holding the substrate W by suction while sealing the peripheral edge of the upper surface of the substrate W to the lower surface of the suction ring 250. Then, when performing the plating process, as shown in FIG. 14, the substrate receiver 236 is lowered by several mm, the substrate W is separated from the claw portion 254, and the substrate W is sucked and held by the suction ring 250 only. Thus, it is possible to prevent the peripheral edge of the surface (lower surface) of the substrate W from being no longer plated due to the presence of the claw portion 254.
[0112]
FIG. 15 shows details of the plating tank 200. The plating tank 200 has a bottom connected to a plating solution supply pipe 308 (see FIG. 17), and a plating solution recovery groove 260 provided in a peripheral wall portion. Inside the plating tank 200, two rectifying plates 262, 264 for stabilizing the flow of the plating liquid flowing upward therethrough are arranged, and further, at the bottom, the plating liquid introduced into the plating tank 200. A temperature measuring device 266 for measuring the temperature of the liquid is provided. Further, the pH of the plating bath 200 is set slightly above the level of the plating solution held in the plating bath 200 on the outer peripheral surface of the peripheral wall of the plating bath 200, and slightly upward in the diameter direction. An injection nozzle 268 for injecting a stop solution composed of a neutral liquid, for example, pure water, is provided. Thus, after the plating is completed, the substrate W held by the head unit 232 is pulled up slightly above the level of the plating solution and temporarily stopped, and in this state, pure water (stop solution) is sprayed from the injection nozzle 268 toward the substrate W. To immediately cool the substrate W, thereby preventing the plating solution remaining on the substrate W from progressing the plating.
[0113]
Furthermore, when the plating process such as idling is not performed on the upper opening of the plating tank 200, the upper opening of the plating tank 200 is closed to prevent unnecessary evaporation of the plating solution from the plating tank 200. A plating tank cover 270 is provided to be freely opened and closed.
[0114]
As shown in FIG. 17, the plating tank 200 extends from a 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 and a three-way valve 306 on the way. Thereby, during the plating process, the plating solution is supplied from the bottom into the plating tank 200 and the overflowing plating solution is collected from the plating solution collecting groove 260 into the plating solution storage tank 302, so that the plating solution is Can be circulated. A plating solution return pipe 312 returning to the plating solution storage tank 302 is connected to one outlet port of the three-way valve 306. Thereby, the plating solution can be circulated even during the standby time of the plating, thereby forming a plating solution circulation system. As described above, by constantly circulating the plating solution in the plating solution storage tank 302 through the plating solution circulation system, the rate of decrease in the concentration of the plating solution is reduced as compared with the case where the plating solution is simply stored, The number of substrates W that can be processed can be increased.
[0115]
In particular, in this example, by controlling the plating solution supply pump 304, the flow rate of the plating solution circulating during the plating standby and during the plating process can be individually set. That is, the circulating flow rate of the plating solution at the time of the plating standby is, for example, 2 to 20 L / min, and the circulating flow rate of the plating solution at the time of the plating treatment is set at, for example, 0 to 10 L / min. As a result, a large circulation flow rate of the plating solution is secured during the standby time of the plating, and the temperature of the plating bath in the cell is maintained at a constant temperature. A protective film (plating film) can be formed.
[0116]
A temperature measuring device 266 provided near the bottom of the plating tank 200 measures the temperature of the plating solution introduced into the plating tank 200 and, based on the measurement result, a heater 316 and a flow meter 318 described below. Control.
[0117]
That is, in this example, the heat exchanger 320 is installed in the plating solution in the plating solution storage tank 302 by using water that has been heated using a separate heater 316 and passed through the flow meter 318 as a heat medium. A heating device 322 for indirectly heating the plating solution and a stirring pump 324 for circulating and stirring the plating solution in the plating solution storage tank 302 are provided. This is because the plating solution may be used at a high temperature (approximately 80 ° C.) in plating, which is used to cope with this. According to this method, the plating solution is much more expensive than the in-line heating method. It is possible to prevent unwanted substances and the like from being mixed into the delicate plating solution.
[0118]
FIG. 16 shows the details of the cleaning tank 202 attached to the side of the plating tank 200. A plurality of spray nozzles 280 for spraying a rinsing liquid such as pure water upward are attached to a nozzle plate 282 at the bottom of the cleaning tank 202, and the nozzle plate 282 is provided at the upper end of a nozzle vertical shaft 284. It is connected to. Further, the nozzle vertical shaft 284 moves up and down by changing the screw position of the screw 287 for adjusting the nozzle position and the nut 288 screwed with the screw 287, whereby the ejection nozzle 280 and the ejection nozzle 280 are moved. The distance to the substrate W arranged above can be adjusted optimally.
[0119]
Further, the cleaning liquid such as pure water is sprayed toward the inside of the cleaning tank 202 in a direction slightly obliquely downward in the diametric direction, being located above the spray nozzle 280 on the outer peripheral surface of the peripheral wall of the cleaning tank 202, and A head cleaning nozzle 286 that sprays a cleaning liquid on at least a portion of the part 232 that is in contact with the plating liquid is provided.
[0120]
In the cleaning tank 202, the substrate W held by the head portion 232 of the substrate head 204 is arranged at a predetermined position in the cleaning tank 202, and a cleaning liquid (rinse liquid) such as pure water is injected from an injection nozzle 280. At this time, a cleaning liquid such as pure water is simultaneously jetted from the head cleaning nozzle 286 to clean at least a portion of the head portion 232 of the substrate head 204 which comes into contact with the plating solution. By cleaning with a cleaning solution, it is possible to prevent deposits from accumulating in portions immersed in the plating solution.
[0121]
In the electroless plating unit 22, the substrate W is sucked and held by the head portion 232 of the substrate head 204 at the position where the substrate head 204 is raised, and the plating solution in the plating tank 200 is circulated as described above. Let it be.
[0122]
Then, 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 unit 232 is immersed in the plating solution in the plating tank 200.
[0123]
Then, after the substrate W is immersed in the plating solution for a predetermined time, the substrate head 204 is raised, and the substrate W is pulled up from the plating solution in the plating tank 200. If necessary, the substrate W is placed on the substrate W as described above. The substrate W is immediately cooled by spraying pure water (stop liquid) from the spray nozzle 268 toward the nozzle, and further, the substrate head 204 is lifted to raise the substrate W to a position above the plating tank 200, and the rotation of the substrate head 204 is stopped. Stop.
[0124]
Next, the substrate head 204 is moved to a position immediately above the cleaning tank 202 while holding the substrate W by the head unit 232 of the substrate head 204 by suction. Then, the substrate W is lowered to a predetermined position in the cleaning tank 202 while rotating the substrate head 204, and a cleaning liquid (rinse liquid) such as pure water is injected from the injection nozzle 280 to wash (rinse) the substrate W. A cleaning liquid such as pure water is sprayed from the cleaning nozzle 286 to clean at least a portion of the head portion 232 of the substrate head 204 that comes into contact with the plating liquid with the cleaning liquid.
[0125]
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 transferred to the transfer robot. The substrate W is transferred to the transfer robot 34 and transferred to the next process.
[0126]
As shown in FIG. 17, the electroplating unit 22 measures the amount of the plating solution held by the electroless plating unit 22 and, for example, absorbs the plating solution by an absorptiometric method, a titration method, an electrochemical measurement, or the like. A plating solution management unit 330 for analyzing the composition and replenishing the insufficient components in the plating solution is provided. A signal processing is performed on these analysis results to supply a deficient component in the plating solution from a replenishing tank (not shown) to the plating solution storage tank 302 using a metering pump or the like so as to manage the amount and composition of the plating solution. Accordingly, thin-film plating can be realized with good reproducibility.
[0127]
The plating solution management unit 330 has a dissolved oxygen concentration meter 332 for measuring the dissolved oxygen of the plating solution held by the electroless plating unit 22 by, for example, an electrochemical method. According to the instruction, the concentration of dissolved oxygen in the plating solution can be controlled to a constant level by, for example, degassing, blowing nitrogen, or the like. As described above, by controlling the concentration of dissolved oxygen in the plating solution to be constant, the plating reaction can be realized with good reproducibility.
When the plating solution is repeatedly used, a specific component may be accumulated by being brought in from the outside or decomposing by itself, which may lead to deterioration in reproducibility of plating and film quality. By adding a mechanism for selectively removing such a specific component, it is possible to extend the liquid life and improve reproducibility.
[0128]
18 and 19 show a post-processing / drying unit 400 in which the post-processing unit 24 and the drying unit 26 shown in FIG. That is, the post-processing / drying unit 400 is a unit that first performs chemical cleaning (post-processing) and pure water cleaning (rinsing), and then completely drys the cleaned substrate W by rotating the spindle. A substrate stage 422 having a clamp mechanism 420 for gripping the W edge portion, and a substrate mounting / dismounting elevating plate 424 for opening and closing the clamp mechanism 420 are provided.
[0129]
The substrate stage 422 is connected to an upper end of a spindle 426 that rotates at a high speed in response to driving of a spindle rotation motor (not shown). A cleaning cup 428 for preventing the processing liquid from scattering is arranged around the substrate W gripped by the clamp mechanism 420, and the cleaning cup 428 moves up and down with the operation of a cylinder (not shown). ing.
[0130]
The post-processing / drying unit 400 includes a chemical liquid nozzle 430 that supplies a processing liquid to the surface of the substrate W gripped by the clamp mechanism 420, and a plurality of pure water nozzles 432 that supply pure water to the back surface of the substrate W. And a rotatable pencil-type cleaning sponge 434 disposed above the substrate W gripped by the clamp mechanism 420. The cleaning sponge 434 is attached to a free end of a swing arm 436 that can swing horizontally. A clean air inlet 438 for introducing clean air into the unit is provided above the post-processing / drying unit 400.
[0131]
In the post-processing / drying unit 400 having such a configuration, the processing liquid is supplied from the chemical liquid nozzle 430 to the cleaning sponge 434 while the substrate W is gripped and rotated by the clamp mechanism 420 and the rotation arm 436 is rotated. Then, by rubbing the cleaning sponge 434 on the surface of the substrate W, post-processing of the surface of the substrate W is performed. Then, pure water is supplied to the back surface of the substrate W from the nozzle 432 for pure water, and the back surface of the substrate W is also washed (rinsed) with the pure water injected from the nozzle 432 for pure water. The substrate W thus cleaned is spin-dried by rotating the spindle 426 at high speed.
[0132]
Although not shown, it is preferable to use a drying unit provided with a dry air unit for supplying dry air to the inside of the drying unit and supplying the dry air to the drying unit during spin drying of the substrate. . This makes it possible to thoroughly dry the substrate and avoid problems such as oxidation of the wiring portion due to adsorbed moisture and generation of a water mark due to mist back.
When using hydrogen gas-dissolved water or electrolytic cathode water as the rinsing liquid, each unit is provided with a device for dissolving hydrogen gas in ultrapure water or a device for electrolyzing ultrapure water. Hydrogen dissolved water or electrolytic cathode water can be supplied to the substrate from the apparatus.
[0133]
Here, in this example, an example is shown in which a Co-WP alloy film is used as the wiring protection film 9, but a wiring protection film made of Co-P, Ni-P or Ni-WP is used. You may make it. Although an example using copper as the wiring material is shown, a copper alloy, silver, a silver alloy, gold, a gold alloy, or the like may be used in addition to copper.
Further, in this example, the protective film 9 is formed on the surface of the buried wiring 8 formed on the substrate. A conductive film (protective film) having a function of preventing diffusion into the substrate may be formed in the same manner as described above.
[0134]
In forming the protective film (plating film) 9 described above, high precision is required for the film thickness, film quality, and selectivity. Therefore, it is necessary to control the time between each process step, which is realized. In order to do so, it is effective to perform all the process steps in the same apparatus, but this substrate processing apparatus can meet this demand.
[0135]
Further, if the chemical solution or the plating solution remains on the surface of the substrate after the chemical solution treatment or the plating treatment, the film forming state such as the in-plane uniformity of the protective film (plating film) and the electrical characteristics of the wiring is adversely affected. For this purpose, chemical solution treatment and pure water rinsing treatment are performed in the same unit to quickly remove the chemical solution and plating solution remaining on the surface of the substrate, thereby reducing the footprint of the device and increasing the yield of semiconductor devices and the like. Can be manufactured.
[0136]
Here, by employing the chemical treatment or the rinsing treatment of the jetting method, the fresh liquid can be always more uniformly dispersed and supplied to the substrate surface, and the treatment time can be reduced. In addition, by adjusting the position of the injection point, the uniformity of the in-plane processing of the protective film can be easily improved. Note that, for example, when a mild treatment is required on the substrate surface, it is a matter of course that an immersion method may be adopted.
[0137]
Since the ejection angle of the liquid from the ejection nozzle is limited, the ejection from one ejection nozzle can cover only a limited range. If the injection distance is too short, a large number of injection nozzles are required to inject a chemical or the like toward the entire surface of the substrate. On the other hand, if the injection distance is too long, an excessive pressurizing device is required, and the height of the entire plating apparatus is increased. For this reason, the number of injection nozzles used in one process is, for example, 1 to 25, and the distance from the injection nozzle to the substrate is preferably, for example, about 10 to 150 mm. Further, the flow rate of a chemical solution or the like injected from one injection nozzle is preferably 0.2 to 1.2 L / min, and the injection pressure is preferably about 10 to 100 kPa.
[0138]
【The invention's effect】
As described above, according to the present invention, it is possible to continuously perform a series of processes for forming a protective film by electroless plating on the bottom surface and side surfaces of the embedded wiring formed on the surface of the substrate, or on the exposed surface. Moreover, since the substrate is finished to a dry state, not only can it be transported to the next step as it is, but also the deterioration of the protective film (plating film) until the next step can be suppressed. This makes it possible to manufacture a semiconductor device or the like with high reproducibility within a substrate surface of a semiconductor wafer or the like and between substrates.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state in which a wiring protection film is formed by electroless plating.
FIG. 2 is a plan layout view of the substrate processing apparatus according to the embodiment of the present invention.
FIG. 3 is a process flow chart in the substrate processing apparatus shown in FIG.
FIG. 4 is a front view of the pre-processing unit when the substrate is delivered.
FIG. 5 is a front view of the pretreatment unit during chemical solution treatment.
FIG. 6 is a front view of the pre-processing unit during rinsing.
FIG. 7 is a cross-sectional view showing the processing head when the pre-processing unit delivers the substrate.
FIG. 8 is an enlarged view of a portion A in FIG. 7;
FIG. 9 is a diagram corresponding to FIG. 8 when the substrate of the pretreatment unit is fixed.
FIG. 10 is a system diagram of a preprocessing unit.
FIG. 11 is a cross-sectional view showing the substrate head when the substrate is delivered in the electroless plating unit.
FIG. 12 is an enlarged view of a portion B in FIG. 11;
FIG. 13 is a diagram corresponding to FIG. 12, showing the substrate head when the substrate is fixed to the electroless plating unit.
FIG. 14 is a diagram corresponding to FIG. 12, showing the substrate head during plating processing of the electroless plating unit.
FIG. 15 is a partially cutaway front view showing the plating tank when the plating tank cover of the electroless plating unit is closed.
FIG. 16 is a sectional view showing a cleaning tank of the electroless plating unit.
FIG. 17 is a system diagram of an electroless plating unit.
FIG. 18 is a vertical sectional front view showing a post-processing / drying unit.
FIG. 19 is a plan view showing a post-processing / drying unit.
[Explanation of symbols]
8 Wiring
9 Protective film
12 Load / Unload unit
18,20 Pretreatment unit
22 Electroless plating unit
24 Post-processing unit
26 Drying unit
28 Heat treatment unit
30 Film thickness measurement unit
34 Transfer Robot
56 Housing
58 Substrate holder
60 processing head
74 Lifting cylinder
80 Mainframe
84a Seal ring
86 Board fixing ring
100 processing tank
102 Lid
112 nozzle plate
112a injection nozzle
120 Chemical tank
122 Chemical pump
124 nozzle plate
124a injection nozzle
126 drain pipe
128 Three-way valve
132 Rinse liquid supply source
200 plating bath
202 Cleaning tank
204 substrate head
230 Housing
232 Head
234 Suction head
250 Suction ring
254 claws
260 Plating solution recovery groove
268 injection nozzle
280 injection nozzle
282 nozzle plate
286 Head cleaning nozzle
302 liquid supply tank
304 liquid supply pump
306 Three-way valve
308 Plating solution supply pipe
316 heater
318 flow meter
320 heat exchanger
322 heating device
324 stirring pump
330 liquid management unit
332 dissolved oxygen concentration meter
400 Post-processing / drying unit
420 Clamp mechanism
422 Substrate Stage
424 Elevating plate for attaching / detaching board
426 spindle
428 cleaning cup
430 chemical liquid nozzle
432 Nozzle for pure water
434 Cleaning sponge
436 swivel arm

Claims (45)

When selectively forming a protective film on the bottom and side surfaces of the embedded wiring formed on the surface of the substrate, or on the exposed surface,
Performing a pre-plating treatment on the substrate,
Electroless plating is performed on the surface of the substrate after the pretreatment to selectively form the protective film on the bottom and side surfaces of the wiring, or on the exposed surface,
A substrate processing method, wherein the processed substrate is dried. 2. The substrate processing method according to claim 1, wherein the substrate to be subjected to the plating pretreatment is put in a dry state. 3. The method according to claim 1, wherein the substrate after the electroless plating is subjected to a post-treatment for improving the selectivity of the protective film, and thereafter, the substrate is dried. The plating pretreatment is characterized by comprising a step of cleaning the surface of the substrate, and a step of activating the surface of the substrate to be plated by applying a catalyst to the surface of the substrate to be plated on the cleaned substrate. The substrate processing method according to claim 1, wherein: When selectively forming the protective film on the exposed surface of the wiring, prior to the step of cleaning the substrate surface, the wiring is exposed by any of chemical mechanical polishing, electrochemical polishing, or composite electrochemical polishing. 5. The method according to claim 4, wherein the surface is flattened. 6. The substrate processing method according to claim 4, wherein said substrate surface cleaning treatment is performed by subjecting the substrate to plasma processing under reduced pressure or normal pressure atmosphere. 7. The substrate processing method according to claim 4, wherein the activation treatment of the base surface to be plated is performed by light irradiation, a CVD method, or a PVD method. The cleaning treatment of the substrate surface is performed by using an inorganic acid having a pH of 2 or less, an acid having a chelating ability of a pH of 5 or less, a solution obtained by adding a chelating agent to an acid having a pH of 5 or less, or an alkali capable of removing a corrosion inhibitor for wiring. 5. The substrate processing according to claim 4, wherein the cleaning is performed by bringing the substrate surface into contact with a solution or a chemical solution comprising an alkaline solution of an amino acid, and thereafter, the substrate surface after the cleaning is rinsed with a rinsing liquid. Method. 9. The substrate processing method according to claim 8, wherein the rinsing liquid is one of pure water, hydrogen gas-dissolved water, and electrolytic cathode water. The application of the catalyst to the surface of the substrate to be plated is performed by bringing the surface of the substrate to be plated into contact with a chemical solution containing palladium, and thereafter, the substrate surface after the application of the catalyst is rinsed with a rinsing liquid. The substrate processing method according to claim 4. The substrate processing method according to claim 10, wherein the rinsing liquid is pure water, hydrogen gas-dissolved water, electrolytic cathode water, or an aqueous solution of a component constituting a plating solution used for electroless plating. The method according to any one of claims 4 to 11, wherein when applying a catalyst to the surface of the substrate to be plated, the concentration of the palladium catalyst on the surface of the substrate to be plated after applying the catalyst is set to 0.4 to 8 µg per 1 cm ^2. The substrate processing method described in the above. 13. The method according to claim 4, wherein the amount of the chemical used in the pretreatment is measured, the composition of the pretreatment is analyzed, and a component that is insufficient in the pretreatment is supplied. The substrate processing method described in the above. 14. The substrate processing method according to claim 1, wherein a deposition rate of the protective film by the electroless plating is set to 10 to 200 [deg.] Per minute. The film formation of the protective film by the electroless plating is performed by bringing the substrate into contact with a plating solution having a pH of 7 to 10 and containing an alkali metal and not containing ammonia. 15. The substrate processing method according to any one of claims to 14. 16. The substrate processing method according to claim 15, wherein the plating solution contains tungsten having a concentration of at least 1.5 g / l or more. 17. The substrate processing method according to claim 1, wherein the protective film is an alloy film containing three elements of cobalt, tungsten, and phosphorus. 18. The substrate processing method according to claim 17, wherein an average composition of the alloy film is in a range of 75 to 90 atm% of cobalt, 1 to 10 atm% of tungsten, and 5 to 25 atm% of phosphorus. 19. The substrate processing method according to claim 15, wherein the amount of the plating solution is measured, the composition of the plating solution is analyzed, and the insufficient components in the plating solution are supplied. 20. The substrate processing method according to claim 15, wherein the dissolved oxygen concentration in the plating solution is measured to control the dissolved oxygen concentration to be constant. The method according to claim 1, wherein after the electroless plating, the substrate is pulled up from the plating solution, and a plating solution is stopped by bringing a stop solution consisting of a neutral solution having a pH of 6 to 7.5 into contact with the substrate surface. 20. The substrate processing method according to any one of 20. 22. The substrate processing method according to claim 21, wherein the stop solution is pure water, hydrogen gas-dissolved water, or electrolytic cathode water. 23. The method according to claim 3, wherein the post-processing of the substrate includes rubbing a surface of the cleaning member against a surface to be processed of the substrate while rotating the cylindrical cleaning member around an axis. The substrate processing method described in the above. 24. The substrate according to claim 3, wherein the post-processing of the substrate includes planarizing a surface to be processed by any one of chemical mechanical polishing, electrochemical polishing, and composite electrochemical polishing. 3. The substrate processing method according to 1. 25. The substrate processing method according to claim 3, wherein a chemical solution containing one or more of a surfactant, an organic alkali, and a chelating agent is used in the post-processing of the substrate. 26. The substrate processing method according to claim 3, wherein after the post-processing of the substrate, the substrate is rinsed with pure water, hydrogen gas-dissolved water, or electrolytic cathode water, and then the substrate is dried. . The humidity of an atmosphere around the substrate is controlled by using dry air or dry inert gas when performing a drying process for putting the substrate into a dry state, according to any one of claims 1 to 26. Substrate processing method. 28. The substrate processing method according to claim 1, wherein a heat treatment for modifying the protective film is performed on the dried substrate. 29. The substrate processing method according to claim 28, wherein the temperature of the heat treatment is 120 to 450C. 30. The substrate processing method according to claim 1, wherein the thickness of the protective film formed on the surface of the base to be plated is measured. A substrate processing apparatus for selectively forming a protective film on the bottom and side surfaces of the embedded wiring formed on the surface of the substrate, or on the exposed surface,
A pretreatment unit for performing plating pretreatment on the substrate surface,
An electroless plating unit that performs electroless plating on the surface of the substrate after the pretreatment and selectively forms the protective film on the bottom and side surfaces of the wiring, or on the exposed surface,
A substrate processing apparatus, comprising: a drying unit for drying the substrate after the electroless plating. 32. The substrate processing apparatus according to claim 31, further comprising a post-processing unit that performs post-processing between the electroless plating unit and the drying unit to improve selectivity of the protective film formed on the substrate surface. The pretreatment unit treats the substrate surface with a chemical solution, removes the chemical solution from the substrate surface, applies a catalyst to the substrate surface, and removes the chemical solution used for the catalyst application from the substrate surface. 33. The substrate processing apparatus according to claim 31, further comprising a second preprocessing unit. The substrate processing apparatus according to any one of claims 31 to 33, wherein the pretreatment unit is configured to spray a chemical solution onto the substrate by spraying. It has a pretreatment liquid management unit that measures the amount of the pretreatment liquid held by the pretreatment unit, analyzes the composition in the pretreatment liquid, and replenishes the insufficient components in the pretreatment liquid. The substrate processing apparatus according to any one of claims 31 to 34. The electroless plating unit includes a plating tank, a plating solution circulating system, and a plating solution storage tank. The plating solution can be circulated between the plating solution storage tanks, and the circulating flow rate of the plating solution during plating standby is 2 to 20 L / min, and the circulating flow rate of the plating solution during plating treatment is 0 to 10 L / min. The substrate processing apparatus according to any one of claims 31 to 35. A plating solution management unit for measuring the amount of the plating solution held by the electroless plating unit, analyzing the composition in the plating solution, and replenishing the insufficient components in the plating solution. 37. The substrate processing apparatus according to any one of 31 to 36. The plating solution management unit has a dissolved oxygen concentration meter that measures dissolved oxygen in the plating solution held by the electroless plating unit, and controls the dissolved oxygen concentration of the plating solution to be constant according to the instruction of the dissolved oxygen concentration meter. The substrate processing apparatus according to claim 37, wherein: The substrate processing according to any one of claims 31 to 38, wherein the post-processing unit uses at least one of a roll scrub cleaning method, a pencil cleaning method, and an etching back method using an etchant. apparatus. 40. The post-processing unit according to claim 31, wherein at least one of a chemical mechanical polishing unit, an electrochemical polishing unit, and a composite electrochemical polishing unit is used. Substrate processing equipment. The substrate processing apparatus according to any one of claims 31 to 40, wherein the drying unit comprises a spin dryer. The substrate processing apparatus according to any one of claims 31 to 41, wherein the drying unit includes a dry air unit that supplies dry air to the drying unit or a dry inert gas unit that supplies a dry inert gas. . 43. The substrate processing apparatus according to claim 31, further comprising a heat treatment unit for performing a heat treatment for modifying the protective film on the substrate dried by the drying unit. The substrate processing apparatus according to any one of claims 31 to 43, further comprising a film thickness measuring unit for measuring a film thickness of the protective film formed on the surface of the base to be plated. 45. An apparatus for dissolving a hydrogen gas in ultrapure water or an apparatus for electrolyzing ultrapure water for supplying hydrogen gas-dissolved water or electrolytic cathode water to each unit. A substrate processing apparatus according to any one of the above.

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