JP2003080421A - Electrochemical machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove (clean) an electrically conductive material filmed over or stuck to a bevel part, etc., of a substrate and to machine an outer peripheral part of the substrate by applying electrochemical machining in place of, for example, conventional general etching by electrochemical action. SOLUTION: This electrochemical machining device is furnished with a plurality of electrodes 36 accumulated with an insulating material 34 between them and has an electrode part 32 having a holding part 38 to face against an outer peripheral part of a work W, an ion exchanger 48 arranged on the holding part 38 of the electrode part 32, a liquid supply part 50 to supply liquid to the holding part 38 of the electrode part 32 and an electric source 40 to apply voltage to the electrodes 36 of the electrode part 32 so that the electrodes 36 become different polarities from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic processing apparatus, and particularly to a bevel for processing a conductive material attached to the outer peripheral portion (bevel portion or edge portion) of a substrate such as a semiconductor wafer or removing impurities. The present invention relates to an electrolytic processing device used as a processing device.

[0002]

2. Description of the Related Art In recent years, as a wiring material for forming a circuit on a substrate such as a semiconductor wafer, copper (Cu) having a low electric resistivity and a high electromigration resistance has been used in place of aluminum or an aluminum alloy. It has become noticeable. This kind of copper wiring is generally formed by embedding copper inside the fine recesses provided on the surface of the substrate. As a method of forming this copper wiring, CV
There are methods such as D, sputtering and plating,
In any case, a copper film is formed on almost the entire surface of the substrate, and unnecessary mechanical copper is removed by chemical mechanical polishing (CMP).

FIG. 6 shows an example of manufacturing a copper wiring board W of this type in the order of steps. First, as shown in FIG. 6A, a conductive layer on a semiconductor substrate 1 on which a semiconductor element is formed. 1a
An insulating film 2 such as an oxide film made of SiO ₂ or a Low-K material film is deposited on the above, and a contact hole 3 and a wiring groove 4 are formed inside the insulating film 2 by a lithographic etching technique. A barrier layer 5 made of TaN or the like,
Further, a seed layer 7 is formed thereon as a power feeding layer for electrolytic plating.

Then, as shown in FIG. 6B, the substrate W
By plating the surface of the copper with copper in the contact hole 3 and the groove 4, the copper film 6 is formed on the insulating film 2.
Deposit. Then, the copper film 6 on the insulating film 2 is removed by chemical mechanical polishing (CMP), and the surface of the insulating film 2 and the surface of the copper film 6 filled in the contact hole 3 and the wiring groove 4 are removed. Make them almost the same plane. As a result, FIG.
As shown in (c), the wiring made of the copper film 6 is formed.

Here, the barrier layer 5 is formed so as to cover almost the entire surface of the insulating film 2, and the seed layer 7 is formed so as to cover almost the entire surface of the barrier layer 5. Therefore, the bevel (outer peripheral portion) of the substrate W has a copper film as a seed layer,
In addition, a copper film may be formed on the inner edge (outer peripheral portion) of the bevel and remain unpolished. Copper easily diffuses into an insulating film in a semiconductor manufacturing process such as annealing,
Since the insulating property may be deteriorated or contamination may occur in the subsequent steps such as transportation and treatment, it is necessary to completely remove it. Therefore, it has been proposed to remove the conductive material such as copper deposited or attached to the bevel portion by etching or the like.

Recently, as the miniaturization and precision of all the components of equipment have been advanced and the manufacturing of materials in the sub-micron region has become common, the influence of the processing method itself on the characteristics of the material becomes more and more significant. ing. Under such circumstances, a machining method in which a tool physically destroys a work piece and removes it, as in conventional machining, causes many defects in the work piece due to the machining. , The characteristics of the work piece deteriorate. Therefore, how to perform processing without deteriorating the characteristics of the material becomes a problem.

As a special processing method developed as a means for solving this problem, there are chemical polishing, electrolytic processing, and electrolytic polishing.
These processing methods, in contrast to conventional physical processing,
The removal processing and the like are performed by causing a chemical dissolution reaction. Therefore, defects such as a work-affected layer and dislocations due to plastic deformation do not occur, and the problem that the above-described processing is performed without impairing the characteristics of the material can be achieved.

[0008]

For example, various kinds of chemicals are used to remove the conductive material such as copper deposited or adhered to the bevel portion by the conventional general etching process. Therefore, there is a problem that not only the post-cleaning needs to be sufficiently performed, but also the load for treating the waste liquid is large. Further, in the future, it is expected that the insulating film will also be changed to a Low-K material having a small dielectric constant. In the Low-K material, the strength is weak and the stress due to CMP or the like cannot be endured.
A process that can process the bevel portion and the like without applying stress to the substrate is desired.

[0009] A process of shaving by CMP while plating is being announced, such as chemical mechanical electropolishing, but by adding machining to the plating growth surface,
This also promoted abnormal growth of plating, causing a problem in film quality.

Further, in the above-described electrolytic processing and electrolytic polishing, the workpiece and the electrolytic solution (NaCl, NaNO ₃ , HF, HC) are used.
It is said that processing proceeds by electrochemical interaction with (1, HNO ₃ , aqueous solution of NaOH, etc.). Therefore,
As long as an electrolytic solution containing such an electrolyte is used, it is inevitable that the workpiece is contaminated with the electrolytic solution.

The present invention has been made in view of the above-mentioned circumstances, and the electroconductivity that is applied to the bevel portion or the like of the substrate is subjected to electrolytic processing by electrochemical action, for example, to perform conventional electrolytic etching instead of general etching. To remove (clean) the material,
An object of the present invention is to provide an electrolytic processing apparatus capable of processing the outer peripheral portion of a substrate.

[0012]

According to a first aspect of the present invention, there is provided an electrode portion comprising a plurality of electrodes laminated with an insulator sandwiched therebetween, the electrode portion having a holding portion facing the outer peripheral portion of the workpiece, and the electrode. A voltage is applied to the electrodes of the electrode part and the liquid supply part for supplying a liquid to the holding part of the electrode part, and the electrodes of the electrode part so that the electrodes have alternately different polarities. An electrolytic processing apparatus having a power supply.

FIG. 1 shows the processing principle of the present invention. This is because the processing electrode (for example, cathode) 1 is formed on the surface of the workpiece 10.
4 and the ion exchanger 12b attached to the power feeding electrode (for example, the anode) 16 are brought into contact or close to each other, and the power source 1 is provided between the machining electrode 14 and the power feeding electrode 16.
7 shows a state in which a liquid 18 such as ultrapure water is supplied from the liquid supply unit 19 between the processing electrode 14 and the power supply electrode 16 and the workpiece 10 while applying a voltage via 7.

As a result, the water molecules 20 in the liquid 18 such as ultrapure water are dissociated into hydroxide ions 22 and hydrogen ions 24 by the ion exchangers 12a and 12b. For example, the generated hydroxide ions 22 are By the electric field between the workpiece 10 and the machining electrode 14 and the flow of the liquid 18 such as ultrapure water, the liquid is supplied to the surface of the workpiece 10 facing the machining electrode 14, and the vicinity of the workpiece 10 here. The concentration of the hydroxide ions 22 is increased, and the atoms 10a of the workpiece 10 are reacted with the hydroxide ions 22. The reaction substance 26 generated by the reaction is
The workpiece 10 is dissolved by the liquid 18 such as ultrapure water and flows along the surface of the workpiece 10 by the flow of the liquid 18 such as ultrapure water.
Removed from. As a result, the surface layer of the workpiece 10 is removed.

Here, the ion exchanger may be formed by laminating a plurality of ion exchange materials. in this way,
When the ion exchanger has a multilayer structure of ion exchange materials such as ion exchange fibers and ion exchange membranes, the total ion exchange capacity of the ion exchanger is increased, and for example, when copper removal (polishing) is performed. In addition, by suppressing the generation of oxides, to prevent the oxides from affecting the processing rate, and further by installing an ion exchange material of a soft material such as a porous film or a woven fabric on the outermost surface layer, for example, a copper film It is possible to suppress the occurrence of abnormal processing such as gouging and peeling after processing.

Further, the ion exchanger may have water absorbency. As a result, liquids such as ultrapure water
It can be made to flow inside the ion exchanger.

The invention according to claim 2 is the electrolytic processing apparatus according to claim 1, characterized in that one or both of an anion exchange group and a cation exchange group are provided to the ion exchanger. . With this, by selectively using an ion exchanger to which one of an anion exchange group or a cation exchange group is provided, or by using an ion exchanger to which both are provided, the range of materials to be processed is widened, It is possible to prevent the generation of impurities due to polarity.

According to a third aspect of the present invention, the liquid is pure water, a liquid having an electric conductivity of 500 μS / cm or less, or an electrolytic solution, and the electrolytic processing apparatus according to the first or second aspect. Is. Here, the pure water is, for example, water having an electric conductivity of 10 μS / cm or less. By performing electrolytic processing using pure water in this way, it is possible to perform clean processing that does not leave impurities on the processed surface, and this makes it possible to simplify the cleaning process after electrolytic processing. Specifically, the cleaning step after electrolytic processing may be one step or two steps.

Further, for example, by adding an additive such as a surfactant to pure water or ultrapure water, the electric conductivity is 500 μS /
cm or less, preferably 50 μS / cm, and more preferably 0.1 μS / cm or less, which is a layer having a uniform suppressing action for preventing migration of ions at the interface between the substrate and the ion exchanger. By this, the concentration of ion exchange (melting of metal) can be relaxed and the processing uniformity can be improved.

This additive serves to prevent localized concentration of ions (for example, hydroxide ions (OH ⁻ ions)). In other words, there is an important factor that creates a uniform surface, "the removal processing speed is uniform at each point on the entire processing surface", and a certain electrochemical removal reaction occurs. Under the circumstances, the cause of the difference in the local removal processing speed is considered to be the local concentration of reactive species,
The main cause of the concentration is considered to be a bias in the electrolytic strength between the machining electrode and the power feeding electrode and a bias in the distribution of ions, which are reactive species, near the surface of the workpiece. Therefore, ions (for example, hydroxide ions) are formed between the workpiece and the ion exchanger.
The local concentration of ions can be suppressed by the presence of an additive that prevents the local concentration of the ions.

Examples of the electrolytic solution include NaCl and Na
Neutral salts such as ₂ SO _4, HCl or H ₂ SO ₄ acid such as, further, an alkali such as ammonia may be used, depending on the characteristics of the workpiece may be suitably selected and used.

The invention according to claim 4 is the electrolytic processing apparatus according to claim 3, wherein the pure water is ultrapure water. Here, ultrapure water has an electric conductivity of 0.1 μS.
/ Cm 2 or less of water. As described above, by using ultrapure water, it is possible to carry out a cleaner processing without leaving impurities on the processing surface.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In this example, a substrate is used as a workpiece, and the bevel etching device is used for removing (polishing) copper deposited or adhered to the outer peripheral portion (bevel portion or edge portion) of the substrate. However, it is needless to say that it can be applied not only to the substrate but also to other electrolytic processing.

2 to 4 show an electrolytic processing apparatus applied to the bevel etching apparatus according to the embodiment of the present invention. This bevel etching apparatus (electrolytic processing apparatus) has a pair of rotatable roller chucks 30 for dropping the substrate W from above and holding it vertically, and an electrode section 32 arranged below the roller chucks 30. ing.

The roller chuck 30 has a V-shaped groove on its outer peripheral end face, and the outer peripheral portion of the substrate W is fitted in the groove to hold the substrate W, and the roller chuck 30 is directly connected to the motor and is the same. This roller chuck 3 rotates in synchronization with the direction.
The substrate W is configured to rotate with the rotation of 0.

The electrode portion 32 has a plurality of electrodes 36 connected in series with an insulator 34 sandwiched therebetween. Then, the cathode and the anode of the power source 40 are alternately connected to the electrode 36, so that in this example, the electrode 36 connected to the cathode of the power source 40 becomes the processing electrode 42, and the electrode connected to the anode is the feeding electrode 44. I am trying to become. This is because, for example, in the case of copper, an electrolytic processing action occurs on the cathode side, and depending on the material to be processed, the cathode side may be the power feeding electrode and the anode side may be the processing electrode. That is, when the material to be processed is, for example, copper, molybdenum, or iron, an electrolytic processing action occurs on the cathode side, so the electrode 36 connected to the cathode of the power source 40 becomes the processing electrode 42, and the electrode 36 connected to the anode is It becomes the power feeding electrode 44. On the other hand, in the case of aluminum or silicon, for example, an electrolytic machining action occurs on the anode side, so that the electrode connected to the anode of the electrode can be the machining electrode and the other can be the power feeding electrode.

Further, on the upper surface of the electrode portion 32, the electrode portion 32 extends linearly over the entire length of the electrode portion 32 in the longitudinal direction.
A groove 38 having a U-shaped cross section along the cross-sectional shape of the outer peripheral portion of the substrate W is provided. The inner surface of the groove (holding portion) 38 is integrally covered with an ion exchanger 48 that is bent in a U shape along the inner surface.

Here, the electrode portion 32 is the roller chuck 3
When the substrate W is held at 0, the lowermost end surface of the substrate W is arranged at a position close to or slightly in contact with the surface of the ion exchanger 48 arranged inside the groove 38 of the electrode portion 32. The groove 38 is arranged such that the outer peripheral edge of the substrate W crosses the plurality of stacked electrodes. In this example, the electrode portion 32 is provided with the groove 38 that linearly extends over the plurality of insulators 34 and the electrodes 36. However, this groove is formed along the shape of the outer peripheral portion of the substrate W. Formed in an arc shape,
The ion exchanger arranged inside the groove may be brought into close contact or light contact with the outer peripheral end surface of the substrate W over the entire length in the length direction. In addition, since the bevel portion is usually a portion within a few millimeters from the wafer edge to the inside, it is necessary to “form a portion to be processed” when etching the conductive film in this portion. Although the groove 38 as the holding portion is formed in the electrode portion 32, the groove may be formed by making the flat plates face each other, and the electrode portion is a flat plate and the flatness of the wafer end is formed by utilizing the elasticity of the ion exchange material. You may make it press.

The ion exchanger 48 is made of, for example, a non-woven fabric having anion or cation exchange ability. The cation exchanger preferably carries a strongly acidic cation exchange group (sulfonic acid group),
It may be one carrying a weakly acidic cation exchange group (carboxyl group). The anion exchanger preferably has a strongly basic anion exchange group (quaternary ammonium group), but may have a weakly basic anion exchange group (tertiary or lower amino group).

Here, for example, the non-woven fabric provided with the strong base anion exchange ability has a fiber diameter of 20 to 50 μm and a porosity of about 9
By a so-called radiation graft polymerization method in which 0% polyolefin non-woven fabric is subjected to graft polymerization after γ-ray irradiation,
It is prepared by introducing a graft chain and then aminating the introduced graft chain to introduce a quaternary ammonium group. The capacity of the ion-exchange groups introduced is determined by the amount of graft chains introduced. To carry out the graft polymerization, for example, acrylic acid, styrene, glycidyl methacrylate,
Furthermore, by using monomers such as sodium styrenesulfonate and chloromethylstyrene, and controlling the concentration of these monomers, the reaction temperature and the reaction time, the amount of grafts to be polymerized can be controlled. Therefore, the ratio of the weight after the graft polymerization to the weight of the material before the graft polymerization is called the graft ratio. This graft ratio can be up to 500%, and the ion exchange groups introduced after the graft polymerization are , A maximum of 5 meq / g is possible.

The non-woven fabric provided with the strong acid cation exchange ability is prepared by the same method as the above-mentioned method of imparting the strongly basic anion exchange ability to a non-woven fabric made of polyolefin having a fiber diameter of 20 to 50 μm and a porosity of about 90%. It is produced by introducing a graft chain by a so-called radiation graft polymerization method of irradiating with and then performing a graft polymerization, and then treating the introduced graft chain with, for example, heated sulfuric acid to introduce a sulfonic acid group. Further, a phosphate group can be introduced by treating with heated phosphoric acid. Here, the graft ratio can be up to 500%, and the ion exchange groups introduced after the graft polymerization can be up to 5 meq / g.

Examples of the material of the ion exchanger 48 include polyolefin polymers such as polyethylene and polypropylene, and other organic polymers. In addition to the non-woven fabric, examples of the material form include woven fabric, sheet, porous material, short fiber and the like.

Here, polyethylene or polypropylene generates a radical in the material by irradiating the material with radiation (γ ray and electron beam) first (pre-irradiation), and then reacts with the monomer to perform graft polymerization. be able to. As a result, a graft chain having high uniformity and less impurities can be formed. On the other hand, other organic polymers can be radically polymerized by impregnating a monomer and irradiating (simultaneous irradiation) with radiation (γ ray, electron beam, ultraviolet ray).
In this case, it lacks uniformity but can be applied to most materials.

As described above, the ion exchanger 48 is made of a non-woven fabric having anion exchange ability or cation exchange ability, so that liquids such as pure water or ultrapure water and electrolytic solution move freely inside the non-woven fabric. Therefore, it becomes possible to easily reach an active site having a water splitting catalytic action inside the nonwoven fabric,
Many water molecules are dissociated into hydrogen ions and hydroxide ions. Furthermore, since the hydroxide ions generated by dissociation are efficiently carried to the surface of the processing electrode 42 as the liquid such as pure water or ultrapure water or the electrolyte moves, a high current can be obtained even with a low applied voltage.

If the ion exchanger 48 is made of one having anion exchange ability or cation exchange ability, not only the material to be electroprocessed can be limited, but also the polarity easily causes impurities. . Therefore,
The ion exchanger 48 may be integrally configured by alternately arranging anion exchangers having anion exchange ability and cation exchangers having cation exchange ability. Further, an anion exchanger having anion exchange ability and a cation exchanger having cation exchange ability may be superposed. Further, such a problem can be solved by providing the ion exchanger 48 with exchange groups having both anion exchange ability and cation exchange ability. Examples of such an ion exchanger include an amphoteric ion exchanger in which an anion exchange group and a cation exchange group are present in an arbitrary distribution, and a bipolar ion in which a cation exchange group and an anion exchange group are present in layers. Examples of the exchanger include a mosaic ion exchanger in which a portion having a cation exchange group and a portion having an anion exchange group are arranged in parallel in the thickness direction. An ion exchanger 48 having either anion exchange ability or cation exchange ability is provided.
Needless to say, it may be used properly according to the material to be processed.

Further, the ion exchanger 48 is made of non-woven fabric, woven fabric,
By forming a multilayer structure in which a plurality of ion-exchange materials such as a porous membrane are stacked, the total ion-exchange capacity of the ion-exchanger 48 is increased, and for example, when removing (polishing) copper, an oxide is used. It is possible to suppress the generation of the oxide and prevent the oxide from affecting the processing rate. In other words, if the total ion exchange capacity of the ion exchanger is smaller than the amount of copper ions taken in during the removal process, oxides will be generated on the surface or inside the ion exchanger, affecting the processing rate. Exert. The cause of this is
It is considered that the amount of ion-exchange groups of the ion-exchanger influences and copper ions having a capacity over the capacity become oxides. Therefore, it is possible to suppress the generation of oxides by increasing the total ion exchange capacity of the ion exchanger having a multilayer structure in which a plurality of ion exchange materials are stacked. In any of the above cases, the ion exchanger is regenerated by the ion exchanger regeneration mechanism for discharging the processed products accumulated in the ion exchanger to suppress the accumulation of copper ions and the like in the ion exchanger. Also, the generation of oxides can be suppressed and the processing rate can be stabilized.

Further, the ion exchanger 48 has a multilayer structure,
An ion exchanger (ion exchange material) made of a soft material such as a porous film or a woven cloth may be installed on the outermost surface layer, or the surface of the ion exchanger 48 may be covered with a water-permeable pad. This prevents the ion exchanger 48 from coming into direct contact with the material to be processed, suppresses the generation of fiber scraps due to the sliding of the ion exchanger 48 with the material to be processed, and prevents the ion exchanger 48 itself. The mechanical life can also be improved.

Further, above the electrode portion 32, there is arranged a pure water nozzle 50 as a pure water supply portion which extends toward the substantially central portion of the groove 38 in the longitudinal direction and supplies pure water or ultrapure water. ing. As a result, pure water or ultrapure water is supplied to the inside of the groove 38 of the electrode portion 32, the inside of the groove 38 is filled with pure water or ultrapure water, and is sequentially discharged. Here, pure water has, for example, an electric conductivity of 10 μS.
/ Cm or less, and ultrapure water is, for example, water having an electric conductivity of 0.1 μS / cm or less. A liquid having an electric conductivity of 500 μS / cm or less or an arbitrary electrolytic solution may be used instead of pure water. By supplying a processing liquid during processing, processing instability due to processing products, gas dissolution, etc. can be removed, and uniform and reproducible processing can be obtained.

Here, the processing electrode 42 and the feeding electrode 44
Oxidation or elution is generally a problem due to the electrolytic reaction. For this reason, it is preferable to use carbon, a relatively inert noble metal, a conductive oxide, or a conductive ceramic as the material of the power feeding electrode 44, rather than the metal or metal compound widely used for the electrode. As an electrode using this precious metal as a material, for example, titanium is used as the base electrode material, and platinum or iridium is attached to the surface by plating or coating, and it is sintered at a high temperature and treated to maintain stability and strength. There are some. When the electrode oxidizes, the electrical resistance of the electrode increases and the applied voltage rises.However, by protecting the electrode surface with a material that is difficult to oxidize such as platinum or a conductive oxide such as iridium, It is possible to prevent a decrease in conductivity due to the oxidation of the material.

Next, a processing example by this electrolytic processing apparatus (bevel etching apparatus) will be described. First, for example, a substrate W having a copper film 6 (see FIG. 6) formed on its surface as a conductor film (processed portion) is dropped between a pair of roller chucks 30 and held vertically. At this time, the lowermost end surface of the substrate W comes close to or lightly contacts the surface of the ion exchanger 48 arranged inside the groove 38 of the electrode portion 32.

In this state, the anode and cathode of the power source 40 are alternately connected to the plurality of electrodes 36, and a predetermined voltage is applied between the processing electrode 42 connected to the cathode and the power feeding electrode 44 connected to the anode. At the same time, the substrate W is rotated. at the same time,
Pure water or ultrapure water is supplied from the pure water nozzle 50 to the inside of the groove 38 to fill the inside of the groove 38 with pure water or ultrapure water. As a result, the electrolytic processing of the conductor film (copper film 6) provided on the substrate W is performed by the hydrogen ions or hydroxide ions generated by the ion exchanger 48. By causing pure water or ultrapure water to flow inside the ion exchanger 48, a large amount of hydrogen ions or hydroxide ions are generated and supplied to the surface of the substrate W, thereby improving efficiency. Good electrolytic processing can be performed.

That is, by allowing pure water or ultrapure water to flow inside the ion exchanger 48, sufficient functional groups (a sulfonic acid group in a strongly acidic cation exchange material) that promote the dissociation reaction of water are provided. Water is supplied to increase the dissociation amount of water molecules, and the processing products (including gas) generated by the reaction with hydroxide ions (or OH radicals) are removed by the flow of water to improve processing efficiency. be able to. Therefore, the flow of pure water or ultrapure water is necessary, and it is desirable that the flow of pure water or ultrapure water be uniform and uniform. Further, it is possible to achieve the uniformity and uniformity of removal of the processed product, and thus the uniformity and uniformity of the processing efficiency.

After the electrolytic processing is completed, the power source 40 is disconnected, the supply of pure water or ultrapure water is stopped, and the substrate W
To stop the rotation of. Thereafter, the processed substrate W is received by a transfer robot or the like and transferred to the next step.

In this example, pure water, preferably ultrapure water, is supplied to the ion exchanger 48. By performing electrolytic processing using pure water or ultrapure water that does not contain an electrolyte, it is possible to prevent excess impurities such as electrolyte from adhering to or remaining on the surface of the substrate W. . Furthermore, copper ions dissolved by electrolysis,
Immediately captured by the ion exchanger 48 in the ion exchange reaction, dissolved copper ions or the like may be deposited again on other portions of the substrate W or may be oxidized and become fine particles to contaminate the surface of the substrate W. Absent.

Since ultrapure water has a large specific resistance and it is difficult for current to flow, the electrical resistance is reduced through the ion exchanger 48. However, by combining it with an electrolytic solution, the electrical resistance is further reduced and consumed. Electric power can be reduced. In addition,
In processing with an electrolytic solution, the processed part of the work piece covers a slightly wider range than the electrode part, but with the combination of ultrapure water and an ion exchanger, almost no current flows in ultrapure water,
Only the area where the processing electrode of the workpiece and the ion exchanger are projected is processed.

Further, instead of pure water or ultrapure water, pure water is used.
Alternatively, you may use an electrolyte solution in which an electrolyte is added to ultrapure water.
Yes. By using an electrolytic solution, the electrical resistance is further reduced.
Power consumption can be reduced. As this electrolyte
Is, for example, NaCl or Na _TwoSO_FourNeutral salts such as HC
l and H_TwoSO_FourAcid such as ammonia, and an alkali such as ammonia.
A solution such as liquid can be used.
You can select and use it.

Further, instead of pure water or ultrapure water, a surfactant or the like is added to pure water or ultrapure water so that the electric conductivity is 500 μS / cm or less, preferably 50 μS / cm or less, and more preferably May use a liquid of 0.1 μS / cm or less (specific resistance of 10 MΩ · cm or more). As described above, by adding the surfactant to pure water or ultrapure water, a layer having a uniform suppressing action for preventing the movement of ions is formed at the interface between the substrate W and the ion exchanger 48. It is possible to reduce the concentration of ion exchange (melting of metal) and improve the flatness of the processed surface. Here, the surfactant concentration is preferably 100 ppm or less. If the value of electric conductivity is too high, the current efficiency is lowered and the processing speed is slowed, but it is 500 μS / cm or less, preferably 50
A desired processing speed can be obtained by using a liquid having an electric conductivity of μS / cm or less, and more preferably 0.1 μS / cm or less.

By providing the ion exchanger 48,
We are trying to greatly improve the processing speed. That is,
The ultrapure water electrochemical processing is based on an electrochemical interaction between OH radicals in ultrapure water and a material to be processed. However, the concentration of OH ⁻ ions, which is a reactive species contained in ultrapure water, is as small as 10 ⁻⁷ mol / L at room temperature and atmospheric pressure, so that it is caused by reactions other than the removal processing reaction (such as oxide film formation). The removal processing efficiency may decrease. Therefore, in order to carry out the removal processing reaction with high efficiency, it is necessary to increase OH ⁻ ions. Therefore, as a method of increasing OH ⁻ ions, there is a method of accelerating the dissociation reaction of ultrapure water with a catalyst material, and an effective catalyst material thereof is an ion exchanger. Specifically, the activation energy associated with the dissociation reaction of water molecules is reduced by the interaction between the water molecules and the functional groups in the ion exchanger. Thereby, dissociation of water can be promoted and the processing speed can be improved.

FIG. 5 shows an electrolytic processing apparatus applied to a bevel etching apparatus according to another embodiment of the present invention. The bevel etching apparatus (electrolytic processing apparatus) of this embodiment is
As the electrode portion 32 having a plurality of electrodes 36, one sufficiently longer than the outer circumference of the substrate W is used, and the electrode portion 32 is arranged so as to be inclined, for example, by an angle θ with respect to the horizontal plane. The substrate W is configured to move along the electrode portion 32 while rolling on the ion exchanger 48 provided inside the groove 38 provided in the. Other configurations are the same as the above-mentioned example. According to this example, since the substrate W naturally rotates due to its own weight, the mechanism for holding and rotating the substrate can be omitted, and the configuration can be simplified.

[0050]

As described above, according to the present invention,
While preventing physical damage to the work piece such as the substrate and impairing the characteristics of the work piece, by electrochemical action, for example, electrolytic processing in place of conventional general etching processing is performed, It is possible to remove (clean) the conductive material deposited or adhered to the bevel portion of the substrate or to process the outer peripheral portion of the substrate. Moreover, the substrate can be processed by using only pure water or ultrapure water, which eliminates the deposition of extra impurities such as electrolyte on the surface of the substrate and the residual impurities. Not only can the cleaning process after the removal process be simplified, but the load of waste liquid treatment can be made extremely small.

[Brief description of drawings]

FIG. 1 is a diagram attached to an explanation of the principle of electrolytic processing of the present invention.

FIG. 2 is a schematic diagram showing an outline of an electrolytic processing apparatus (bevel etching apparatus) according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an electrode portion.

FIG. 4 is an enlarged cross-sectional view of an electrode of an electrode section.

FIG. 5 is a schematic diagram showing an outline of an electrolytic processing apparatus (bevel etching apparatus) according to an embodiment of the present invention.

FIG. 6 is a diagram showing an example of forming a copper wiring in the order of steps.

[Explanation of symbols]

30 roller chuck 32 electrodes 34 Insulator 36 electrodes 38 grooves 40 power 42 Processing electrode 44 feeding electrode 48 ion exchanger 50 Pure water nozzle

Front page continuation (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) H01L 21/3213 H01L 21/306 L (72) Inventor Masayuki Kasukawa 11-1 Haneda-Asahicho, Ota-ku, Tokyo Ebara Co., Ltd. (72) Inventor Takayuki Saito 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company Ebara Research Institute (72) Inventor Yasushi Toma 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute (72) Inventor Saku Suzuki 4-2-1 Honfujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute (72) Inventor Kaoru Yamada 4-2-1 Honfujisawa, Kanagawa Formula company EBARA Research Institute (72) Inventor Yuji Makida 4-2-1 Motofujisawa, Fujisawa City, Kanagawa Stock Company EBARA Research Institute (72) Inventor Hozumi Yasuda 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo F term in EBARA CORPORATION (reference) 3C059 AA02 AB01 EA02 EA10 EB08 4M104 BB01 BB02 BB04 BB16 DD64 HH14 HH20 5F033 HH04 HH05 HH06 HH07 HH08 HH11 HH20 QQ08 QQ19 XX03 XX21 5F043 EE07 EE14 EE35 GG10

Claims (4)

[Claims] 1. An electrode part comprising a plurality of electrodes laminated with an insulator sandwiched between them, the electrode part having a holding part facing the outer peripheral part of the workpiece, an ion exchanger arranged in the holding part of the electrode part, An electrolytic processing apparatus comprising: a liquid supply unit that supplies a liquid to the holding unit of the electrode unit; and a power supply that applies a voltage to the electrodes of the electrode unit so that the electrodes have alternating polarities. 2. The electrolytic processing apparatus according to claim 1, wherein one or both of an anion exchange group and a cation exchange group are provided to the ion exchanger. 3. The liquid is pure water and has an electric conductivity of 500.
The electrolytic processing apparatus according to claim 1, wherein the electrolytic processing apparatus is a liquid or an electrolytic solution having a μS / cm or less. 4. The electrolytic processing apparatus according to claim 3, wherein the pure water is ultrapure water.