JP2006009103A - Electrolytic processing apparatus and method for conditioning contact member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always satisfactorily perform uniform electrolytic processing without exerting adverse influence on working properties and the service life of a contact member. <P>SOLUTION: The subject electrolytic processing apparatus includes; a processing electrode 84 capable of bringing into contact with or closing to a workpiece W; a feeding electrode 86 for feeding electricity to the workpiece; a contact member 40 disposed between the workpiece and at least one of the processing electrode and the feeding electrode and is freely brought into contact with the workpiece; a power source 90 for applying voltage between the processing electrode and the feeding electrode; drive parts 62, 82 for relatively driving the workpiece and one of the processing electrode and the feeding electrode; liquid feeding parts 80a, 94 for feeding a fluid between the workpiece and one of the processing electrode and the feeding electrode; and a conditioning part 50 provided with a conditioner 48 which is brought into contact with the contact face of the contact member with the workpiece and performing the conditioning of the contact face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrolytic processing apparatus used for processing a conductive material formed on the surface of a substrate such as a semiconductor wafer or removing impurities adhering to the surface of the substrate, and the electrolytic processing apparatus. The present invention relates to a method for conditioning a contact member provided.

  In recent years, as a wiring material for forming a circuit on a substrate such as a semiconductor wafer, the movement of using copper (Cu) having low electrical resistivity and high electromigration resistance instead of aluminum or an aluminum alloy has become prominent. . This type of copper wiring is generally formed by embedding copper in a fine recess provided on the surface of the substrate. Methods for forming this copper wiring include chemical vapor deposition (CVD), sputtering, and plating, but in any case, copper is deposited on almost the entire surface of the substrate, and chemical mechanical polishing is performed. Unnecessary copper is removed by (CMP).

FIG. 1A to FIG. 1C show a manufacturing example of this type of copper wiring board W in the order of steps. First, as shown in FIG. 1A, an insulating film 2 such as an oxide film made of SiO ₂ or a low-k material film is deposited on a conductive layer 1a on a semiconductor substrate 1 on which a semiconductor element is formed. Then, the contact hole 3 and the wiring groove 4 are formed by the lithography / etching technique. A barrier film 5 made of TaN or the like is formed thereon, and a seed layer 7 as a power feeding layer for electrolytic plating is formed thereon by sputtering or CVD.

  Then, by copper plating on the surface of the substrate W, the contact hole 3 and the wiring groove 4 of the semiconductor substrate W are filled with copper and a copper film is formed on the insulating film 2 as shown in FIG. 6 is deposited. Thereafter, the copper film 6, the seed layer 7 and the barrier film 5 on the insulating film 2 are removed by chemical mechanical polishing (CMP), and the surface of the copper film 6 filled in the contact hole 3 and the wiring groove 4 The surface of the insulating film 2 is substantially flush with the surface. As a result, a wiring made of the copper film 6 is formed as shown in FIG.

  In recent years, as the miniaturization and high precision have progressed in the components of all devices, and the manufacturing in the sub-micron region has become common, the influence of the processing method itself on the characteristics of the material has been increasing. Under such circumstances, the machining method in which the tool removes the workpiece while physically destroying it, as in conventional machining, because many defects are generated in the workpiece by machining. As a result, the properties of the workpiece are deteriorated. Therefore, it becomes a problem how the processing can be performed without impairing the characteristics of the material.

  Special processing methods developed as means for solving this problem include chemical polishing, electrolytic processing, and electrolytic polishing. In contrast to conventional physical processing, these processing methods perform removal processing and the like by causing a chemical dissolution reaction. Therefore, defects such as work-affected layers and dislocations due to plastic deformation do not occur, and the problem of performing processing without impairing the properties of the above-described materials is achieved.

  For example, the CMP process generally requires a considerably complicated operation, is complicated in control, and has a considerably long processing time. Furthermore, not only is it necessary to sufficiently perform post-cleaning of the substrate after polishing, but there are also problems such as a large load for draining the slurry and cleaning liquid. For this reason, there has been a strong demand to omit CMP itself or reduce this load. In the future, the interlayer insulating film is also expected to change to a low-k material having a low dielectric constant, and the low-k material has low mechanical strength and cannot withstand stress caused by CMP. Therefore, there is a demand for a process that enables planarization without applying stress to the substrate.

  As means for solving such a problem, a contact member (for example, an ion exchanger) is disposed between the electrode and the workpiece, and a liquid having a large electric resistance such as pure water or ultrapure water is used as an electrolytic solution. There has been proposed electrolytic processing that eliminates mechanical stress applied to the workpiece by performing processing and that is easy for post-cleaning (see, for example, Patent Document 1).

  As shown in FIG. 2, an ion exchanger (contact member) 12 a attached to the processing electrode 14 and an ion exchanger (contact member) 12 b attached to the feeding electrode 16 are provided on the surface of the workpiece 10. While being brought into contact or close to each other, a voltage is applied between the processing electrode 14 and the power supply electrode 16 via the power source 17, while the liquid supply unit 19 between the processing electrode 14, the power supply electrode 16 and the workpiece 10 is ultrapure. A processing liquid 18 such as water is supplied to remove the surface layer of the workpiece 10. According to this electrolytic processing, water molecules 20 in the processing 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, generated hydroxide ions. 22 is supplied to the surface of the workpiece 10 facing the machining electrode 14 by the electric field between the workpiece 10 and the machining electrode 14 and the flow of the machining liquid 18 such as ultrapure water. The density of the hydroxide ions 22 in the vicinity of the workpiece 10 is increased, and the atoms 10a of the workpiece 10 and the hydroxide ions 22 are reacted. The reaction material 26 generated by the reaction is dissolved in the processing liquid 18 such as ultrapure water, and the work material 18 such as ultrapure water flows along the surface of the workpiece 10 from the work 10. Removed.

JP 2003-145354 A

  For example, in the electrolytic processing in which electrolytic processing is performed by bringing a contact member made of an ion exchanger into contact with a workpiece, the processing selectively proceeds at or near the contact portion between the contact member and the processing surface of the workpiece. Therefore, in order to always maintain good processing characteristics such as processing rate and in-plane uniformity of processing, the state of contact surface (flatness and surface roughness) of the contact member with the workpiece is always kept constant. It is desirable.

  However, due to variations in the state (flatness and surface roughness) of the contact surface of the contact member with the workpiece before and after replacement, deterioration due to use of the contact surface of the contact member with the workpiece, etc. The state of the contact surface with the workpiece may change. Then, the processing characteristics such as the processing rate of the workpiece to be electrolytically processed in contact with the contact member and the in-plane uniformity of processing change under the influence of the state of the contact surface of the contact member with the workpiece. For example, when the contact area between the workpiece surface of the workpiece and the contact member changes, the voltage applied between the machining electrode and the power supply electrode and the flow between the workpiece and the machining electrode and / or the power supply electrode flow. The distribution of current changes or the amount of fluid inflow changes, which adversely affects machining characteristics and contact member life. In particular, when the contact area is small, current concentrates and flows on the contact surface of the contact member with the workpiece. As a result, processing products adhere to the surface of the contact member or local heat is generated. The contact member melts. Further, when the contact pressure between the workpiece and the contact member changes and becomes high, the surface of the workpiece is damaged and scratches or the like are generated on the surface.

  The present invention has been made in view of the above circumstances, and an electrolytic processing apparatus capable of always performing good and uniform electrolytic processing without adversely affecting the processing characteristics and the life of the contact member, and the electrolytic process. It aims at providing the conditioning method of the contact member with which the processing apparatus is equipped.

  According to a first aspect of the present invention, at least one of a machining electrode that is close to the workpiece, a feeding electrode that feeds power to the workpiece, and the workpiece and the machining electrode or the feeding electrode is provided. A contact member that is arranged and freely contactable with the workpiece, a power source that applies a voltage between the machining electrode and the power supply electrode, and a relative relationship between the workpiece and at least one of the processing electrode or the power supply electrode. A contact portion that contacts the contact surface of the workpiece with the drive portion that moves, a fluid supply portion that supplies fluid to at least one of the workpiece and the processing electrode or the feeding electrode, and An electrolytic processing apparatus having a conditioning unit including a conditioner for conditioning the contact surface.

  Accordingly, the contact surface of the contact member that contacts the workpiece during electrolytic processing is contacted with the workpiece via the conditioner of the conditioning unit so that the flatness and the surface roughness are equal to or less than predetermined values. Can be conditioned.

  According to a second aspect of the present invention, at least one of a machining electrode that is close to the workpiece, a feeding electrode that feeds power to the workpiece, and the workpiece and the machining electrode or the feeding electrode is provided. A contact member that is arranged and freely contactable with the workpiece, a power source that applies a voltage between the machining electrode and the power supply electrode, and a relative relationship between the workpiece and at least one of the processing electrode or the power supply electrode. A drive unit that moves, a fluid supply unit that supplies fluid to at least one of the workpiece and the processing electrode or the feeding electrode, and a contact surface of the contact member with the workpiece. An electrolytic processing apparatus comprising a conditioner for conditioning the contact surface and a holding portion for selectively holding one of the workpieces.

  Thus, by operating the conditioner as if it is electrolytically processed in a state where the conditioner is held by the holding portion that holds the workpiece during electrolytic processing and releases the substrate after electrolytic processing, the contact member Conditioning can be performed with a conditioner in which the contact surface with the workpiece is held by a holding portion.

The invention according to claim 3 is the electrolytic processing apparatus according to claim 1 or 2, wherein the contact member is made of a member including an electrolyte, an insulator, or any combination thereof.
The invention according to claim 4 is the electrolytic processing apparatus according to claim 3, wherein the electrolyte is made of a solid electrolyte.

The invention according to claim 5 is the electrolytic processing apparatus according to claim 4, wherein the solid electrolyte is made of an ion exchanger.
Thus, by using an ion exchanger as a solid electrolyte, the dissociation of water molecules in a liquid such as ultrapure water into hydroxide ions and hydrogen ions is promoted, and the amount of dissociation of water molecules is increased. be able to.
The invention according to claim 6 is characterized in that the contact member is formed of a conductive pad, and is disposed between the workpiece and the processing electrode or the feeding electrode. Or it is the electrolytic processing apparatus of 2.

The invention according to claim 7 is characterized in that at least a portion of the conditioner that contacts the contact surface of the contact member is composed of a polishing body to which abrasive grains are fixed. Electrolytic processing device.
Stable polishing while preventing scratches from occurring on the contact surface of the contact member with the workpiece by forming a hard polishing surface with a polishing body (fixed abrasive) with fixed abrasive grains Speed and high flatness can be obtained. In addition, conditioning can be performed while supplying a polishing liquid that does not contain abrasive grains, pure water, ultrapure water, or a liquid having an electric conductivity of 500 μm or less, whereby the contact member is conditioned simultaneously with electrolytic processing. At the same time, the load of environmental problems can be reduced.

The invention according to claim 8 is characterized in that the flatness of the polishing surface that contacts the contact surface of the contact member of the polishing body is 100 μm or less, and the diameter of the abrasive grains is 5 μm or less. It is an electrolytic processing apparatus of description.
Accordingly, the contact member can be conditioned so that the flatness of the contact surface of the contact member with the workpiece is 100 μm or less and the surface roughness is 5 μm or less.

The invention according to claim 9 is the electrolytic processing apparatus according to any one of claims 1 to 6, wherein the conditioner comprises a polishing pad that performs polishing using loose abrasive grains.
The polishing pad is generally low in rigidity, but the flatness can be increased by using a polishing pad having high rigidity.
The invention according to claim 10 is the electrolytic processing apparatus according to claim 9, wherein the diameter of the loose abrasive grains is 5 μm or less.

The invention according to claim 11 is a method in which a conditioner is brought into contact with a contact surface of the contact member that performs electrolytic processing by contacting the workpiece, and the contact member and the conditioner are in the presence of a liquid. The contact member is conditioned by relatively moving the contact member to condition the contact member.
The invention according to claim 12 is characterized in that conditioning of the contact member is performed at an interval of electrolytic processing after the contact member is installed or replaced, or simultaneously with electrolytic processing of a workpiece. This is a method for conditioning a contact member.

According to a thirteenth aspect of the present invention, the conditioner is held by a holding portion that detachably holds the workpiece, and a contact member that performs electrolytic machining by contacting the workpiece is contacted with the workpiece. A contact member conditioning method, wherein a conditioner is brought into contact and the contact member and the conditioner are relatively moved in the presence of a liquid to condition the contact member.
The invention according to claim 14 is the method for conditioning a contact member according to claim 13, wherein the conditioning of the contact member is performed after the contact member is installed or replaced, or at an interval of electrolytic processing.

  The invention according to claim 15 is characterized in that, by conditioning the contact member, the flatness of the contact surface of the contact member with the workpiece is set to 100 μm or less, and the surface roughness of the contact surface is set to 5 μm or less. It is a conditioning method of the contact member in any one of Claims 11 thru | or 14.

  According to the present invention, the contact surface of the contact member that comes into contact with the workpiece during electrolytic processing is contacted with the workpiece via the conditioner so that the flatness and the surface roughness are not more than predetermined values. Conditioning can be performed, whereby the contact state of the contact member with the surface of the workpiece can be kept constant, and the processing characteristics in electrolytic processing can be stabilized and the life of the contact member can be extended.

Hereinafter, an electrolytic processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a plan view showing a configuration of the substrate processing apparatus including the electrolytic processing apparatus according to the embodiment of the present invention. As shown in FIG. 3, this substrate processing apparatus carries out a cassette containing a substrate W having a copper film 6 as a conductor film (processed part) on the surface, for example, as shown in FIG. A pair of loading / unloading sections 30 serving as loading / unloading sections, a reversing machine 32 for reversing the substrate W, an electrolytic processing apparatus 34, and a cleaning section 39 for cleaning and drying the substrate W after electrolytic processing are provided. . These devices are arranged in series, and a transfer robot 36 as a transfer device that transfers the substrate W between these devices and delivers it is arranged in parallel with these devices. In addition, a monitor unit 38 that monitors a voltage applied between a machining electrode 84 and a power supply electrode 86 (described later) or a current flowing between them during the electrolytic machining by the electrolytic machining apparatus 34 is provided in the load / unload unit 30. Adjacent to each other.

  4 is a longitudinal sectional view schematically showing the electrolytic processing apparatus 34, and FIG. 5 is a plan view of FIG. As shown in FIGS. 4 and 5, the electrolytic processing apparatus 34 includes an electrode part 42 having a contact member 40 attached to the surface thereof, and a substrate holding part 44 detachably holding the substrate W between the electrode part 42 and the electrode part 42. An electrolytic processing unit 46 that performs electrolytic processing on the substrate W, and a conditioning unit 50 that conditions the surface (upper surface) of the contact member 40 with a conditioner 48 are provided.

  In this example, as the electrode part 42, an electrode part having a diameter twice or more as large as the diameter of the substrate W held by the substrate holding part 44 is used, and the substrate holding part 44 and the conditioner 48 are located on both sides of the center of the electrode part 42. In this example, the entire surface of the substrate W is electrolytically processed so that the contact member 40 of the electrode portion 42 can be conditioned at the same time.

  The electrolytic processing unit 46 includes an arm 52 that can move up and down and swing in the horizontal direction, and a substrate holding unit 44 that holds the substrate W by suctioning the surface downward (face-down) at the free end of the arm 52. It is installed vertically. The arm 52 is attached to the upper end of the swing shaft 56 connected to the swing motor 54 and swings in the horizontal direction as the swing motor 54 is driven. The swing shaft 56 is connected to a ball screw 58 extending in the vertical direction, and moves up and down together with the arm 52 as the vertical movement motor 60 connected to the ball screw 58 is driven.

  The substrate holding unit 44 is connected to a rotation motor 62 as a first drive unit that relatively moves the substrate W held by the substrate holding unit 44 and the electrode unit 42. As the rotation motor 62 is driven, the substrate holding unit 44 is connected. Rotates (spins). Further, as described above, the arm 52 can move up and down and swing in the horizontal direction, and the substrate holder 44 can move up and down and swing in the horizontal direction integrally with the arm 52. Yes.

  The conditioning unit 50 is also provided with an arm 64 that can move up and down and swing in the horizontal direction. A support 66 is suspended from the free end of the arm 64, and a conditioner 48 is attached to the lower surface of the support 66. It has been. The arm 64 is attached to the upper end of a swing shaft 70 connected to the swing motor 68 and swings in the horizontal direction as the swing motor 68 is driven. The swinging shaft 70 is connected to a ball screw 72 extending in the vertical direction, and moves up and down together with the arm 64 as the vertical movement motor 74 connected to the ball screw 72 is driven.

  The support 66 is connected to a rotation motor 76 as a drive unit that relatively moves the conditioner 48 attached to the support 66 and the electrode portion 42, and rotates (spins) as the rotation motor 76 is driven. To do. Further, as described above, the arm 64 can move up and down and swing in the horizontal direction, and the support 66 can move up and down and move in the horizontal direction integrally with the arm 64. .

In this example, the conditioner 48 is composed of a polishing body (fixed abrasive grains) in which abrasive grains such as cerium oxide (CeO ₂ ) are fixed in a plate shape using a binder such as phenol resin. Then, this surface (lower surface) is used as a polishing surface 48a, and in the presence of liquid (polishing liquid), the polishing surface 48a is pressed against the contact surface (upper surface) 40a of the contact member 40 with the substrate W with a predetermined pressure. Conditioning is performed by polishing the contact surface 40a of the contact member 40 by causing the conditioner 48 and the contact member 40 to move relative to each other.

  In this way, by forming the conditioner 48 with a polishing body (fixed abrasive grains) to which abrasive grains are fixed, a hard polishing surface 48a can be obtained, whereby the contact surface 40a of the contact member 40 with the substrate W is obtained. It is possible to obtain a high flatness by polishing the contact surface 40a at a stable polishing rate while preventing the surface from being scratched. Moreover, the contact member 40 can be conditioned while supplying a polishing liquid that does not contain abrasive grains, pure water, ultrapure water, or a liquid having an electric conductivity of 500 μm or less. While simultaneously conditioning (polishing) the contact member 40, it is possible to reduce the burden of environmental problems.

  The flatness of the polishing surface 48a of the conditioner (polishing body) 48 that contacts the contact surface 40a of the contact member 40 is preferably 100 μm or less, and the diameter of the fixed abrasive grains is preferably 5 μm or less. Thus, the contact surface 40a of the contact member 40 with the substrate W can be conditioned (polished) by the conditioner 48 so that the flatness is 100 μm or less and the surface roughness is 5 μm or less.

  For example, the conditioner may be constituted by a polishing pad made of a resin material such as nonwoven fabric, sponge, or urethane foam, and polishing (conditioning) may be performed using loose abrasive grains. Such a polishing pad generally has low rigidity, but the flatness can be increased by using a polishing pad having high rigidity. Further, by using loose abrasive grains having a diameter of 5 μm or less, the contact surface 40a of the contact member 40 with the substrate W can be conditioned (polished) so that the surface roughness is 5 μm or less.

  When a polishing pad is used as the conditioner 48, for example, the material of the abrasive grains and the abrasive particle size, the contact pressure of the contact member 40 of the conditioner 48 on the contact surface 40a with the substrate W, the substrate of the contact member 40 of the conditioner 48, and the like. The amount of conditioning (polishing amount) is controlled by the amount of contact with W on the contact surface 40a, the relative movement speed between the conditioner 48 and the contact member 40, and the conditioning time (polishing time).

  The electrode unit 42 includes a disk-shaped table 80 made of an insulator, and a hollow motor 82 that is directly connected to the table 80 and serves as a drive unit that rotates (spins) the table 80. A plurality of fan-shaped machining electrodes 84 and power supply electrodes 86 are alternately embedded on the upper surface of the table 80 so that the surface (upper surface) is exposed. The machining electrodes 84 and the power supply electrodes 86 are formed on the substrate W during electrolytic processing. Is integrally covered with a sheet-like contact member 40 that comes into contact with the surface (lower surface) of the sheet.

  The processing electrode 84 is connected to the cathode of the power source 90 via the slip ring 88, and the power supply electrode 86 is connected to the anode of the power source 90 via the slip ring 88. For example, in the case of processing copper, an electrolytic processing action occurs on the cathode side, so that the electrode connected to the cathode serves as a processing electrode and the electrode connected to the anode serves as a feeding electrode. On the other hand, depending on the processing material, the feeding electrode 86 may be connected to the cathode of the power source 90 and the processing electrode 84 may be connected to the anode of the power source 90. For example, when the material to be processed is, for example, aluminum or silicon, an electrolytic processing action occurs on the anode side. Therefore, the electrode connected to the anode of the power source becomes the processing electrode, and the electrode connected to the cathode becomes the power supply electrode.

  Here, the processing electrode 84 and the feeding electrode 86 generally have a problem of oxidation or elution due to an electrolytic reaction. For this reason, it is preferable to use carbon, a comparatively inactive noble metal, a conductive oxide, or a conductive ceramic rather than the metal and metal compound which are widely used for an electrode as a raw material of an electrode. As an electrode made of this noble metal, for example, titanium is used as the base electrode material, platinum or iridium is attached to the surface by plating or coating, and sintering is performed at a high temperature to maintain stability and strength. Can be mentioned. Ceramic products are generally obtained by heat treatment using inorganic materials as raw materials, and products having various characteristics are made using various nonmetals, metal oxides, carbides and nitrides as raw materials. Some of these are conductive ceramics. When the electrode is oxidized, the electrical resistance value of the electrode increases, leading to an increase in applied voltage. Thus, by protecting the electrode surface with a material that is difficult to oxidize such as platinum or a conductive oxide such as iridium, the electrode is protected. A decrease in conductivity due to oxidation of the material can be prevented.

In this example, the contact member 40 is made of a member having an electrolyte, such as an ion exchanger. In this way, by sandwiching the contact member 40 made of an ion exchanger between the substrate W and the processing electrode 84 and the power supply electrode 86, the processing speed can be greatly improved. That is, ultrapure water electrochemical processing is based on chemical interaction between hydroxide ions in ultrapure water and the material to be processed. However, since the hydroxide ion concentration, which is a reactive species contained in ultrapure water, is as small as 10 ⁻⁷ mol / L at room temperature and pressure, reactions other than removal processing reactions (oxide film formation, etc.) It is conceivable that the removal processing efficiency is reduced by the above. For this reason, in order to perform the removal processing reaction with high efficiency, it is necessary to increase the hydroxide ions. Thus, as a method of increasing hydroxide ions, there is a method of promoting the dissociation reaction of ultrapure water with a catalyst material, and an ion exchanger is an effective catalyst material. Specifically, the activation energy related to the dissociation reaction of water molecules is reduced by the interaction between the functional groups in the ion exchanger and the water molecules. Thereby, dissociation of water is promoted, and the processing speed can be improved.

  Further, in this example, the contact member 40 made of an ion exchanger is brought into contact with the substrate W during the electrolytic processing. In a state where the contact member 40 made of an ion exchanger and the substrate W are close to each other, although depending on the size of the gap, the electric resistance is large to some extent, so that the voltage when trying to give the required current density is large. Become. However, on the other hand, since it is non-contact, it is easy to make a flow of pure water or ultrapure water along the surface of the substrate W, and reaction products on the substrate surface can be removed with high efficiency. On the other hand, when the contact member 40 made of an ion exchanger is brought into contact with the substrate W, the electrical resistance becomes extremely small, the applied voltage can be reduced, and the power consumption can be reduced.

  Further, when the voltage is increased to increase the processing speed and the current density is increased, a discharge may occur when the resistance between the electrode and the substrate (workpiece) is large. When electric discharge occurs, pitching occurs on the surface of the workpiece, and the uniformity and flattening of the processed surface becomes difficult. On the other hand, when the contact member 40 made of an ion exchanger is brought into contact with the substrate W, the electrical resistance is extremely small, so that such discharge can be prevented from occurring.

  In this embodiment, pure water, preferably ultrapure water is supplied to the upper surface of the electrode part 42 through a through hole 80 a provided in the table 80 of the electrode part 42. That is, a through-hole 80a as a liquid supply unit for supplying pure water, preferably ultrapure water, is provided at the center of the table 80. The through hole 80 a is connected to a pure water supply pipe 92 that extends inside the hollow portion of the hollow motor 82. Pure water (ultra-pure water) is supplied to the entire surface of the contact member 40 after being supplied to the upper surface of the electrode portion 42 through the through hole 80a.

  Further, as shown in FIG. 5, a plurality of supply ports are provided above the electrode portion 42, extend along the diameter direction of the electrode portion 42, and pure water, preferably super A pure water nozzle 94 is disposed as a liquid supply unit that supplies pure water. Thereby, pure water, preferably ultrapure water is simultaneously supplied from the vertical direction of the electrode part 42.

  Next, substrate processing (electrolytic processing) using the substrate processing apparatus provided with the electrolytic processing apparatus 34 in this embodiment will be described. First, for example, as shown in FIG. 1B, a cassette containing a substrate W on which a copper film 6 is formed as a conductor film (processed portion) on the surface is set in a load / unload unit 30. A single substrate W is taken out by the transfer robot 36. The transfer robot 36 transfers the taken-out substrate W to the reversing machine 32 as necessary, and reverses the substrate W so that the surface on which the conductive film (copper film 6) is formed faces downward.

  The transport robot 36 receives the inverted substrate W, transports it to the electrolytic processing apparatus 34, and sucks and holds it on the substrate holder 44. Then, the arm 52 of the electrolytic processing unit 46 is moved to move the substrate holding unit 44 holding the substrate W to a processing position above the electrode unit 42. Next, the vertical movement motor 60 is driven to lower the substrate holding portion 44, and the substrate W held by the substrate holding portion 44 is brought into contact with the upper surface of the contact member 40 of the electrode portion 42 with a predetermined pressure.

Contact pressure between the contact member 40 and substrate W, from the viewpoint of low contact ^{pressure, 13.7kPa (140gf / cm 2,} 2.0psi) or less, more preferably 6.86kPa ^(70gf / cm 2, 1.0psi ) Or less, more preferably 3.43 Pa (35 gf / cm ² , 0.5 psi) or less.

In this state, the rotation motor 62 is driven to rotate (rotate) the substrate W integrally with the substrate holding portion 44, and at the same time, the hollow motor 82 is driven to rotate (rotate) the electrode portion 42. As a result, the substrate W and the electrode part 42 are moved relative to each other. At this time, a fluid such as pure water, preferably ultrapure water is applied to the upper surface of the electrode portion 42 through the pure water supply pipe 92 and the through hole 80a provided in the table 80 of the electrode portion 42, and further through the pure water nozzle 94. Supply.
Note that pure water or the like may be supplied to the upper surface of the electrode portion 42 through one of the pure water supply pipe 92 and the through hole 80 a provided in the table 80 of the electrode portion 42 or the pure water nozzle 94. In the conditioning unit 50, pure water or the like may be supplied to the upper surface of the electrode unit 42 through the inside of the support 66 and the conditioner 48.

  Then, a predetermined voltage is applied between the processing electrode 84 and the power supply electrode 86 by the power source 90, and processing is performed by hydrogen ions or hydroxide ions generated by the contact member (ion exchanger) 40 made of a solid electrolyte. In the electrode 84, electrolytic processing of the conductor film (copper film 6) on the surface of the substrate W is performed.

  During the electrolytic processing, the voltage applied between the processing electrode 84 and the power supply electrode 86 or the current flowing therebetween is monitored by the monitor unit 38 to detect the end point (processing end point). That is, when electrolytic processing is performed in the state where the same voltage (current) is applied, a difference occurs in the current (applied voltage) flowing depending on the material. For example, as shown in FIG. 6 (a), when the current that flows when the surface of the substrate W on which the material B and the material A are sequentially formed is subjected to electrolytic processing, the material A is electrolytically processed. While a constant current flows during the process, the current that flows at the time of transition to processing of a different material B changes. Similarly, even if the voltage is applied between the machining electrode 84 and the feeding electrode 86, a constant voltage is applied while the material A is electrolytically processed, as shown in FIG. 6B. However, the voltage applied at the time of shifting to processing of a different material B changes. 6A shows a case where the current is less likely to flow when the material B is electrolytically processed than when the material A is electrolytically processed. FIG. 6B shows the case where the material B is electrolytically processed. Shows an example where the voltage is higher than when the material A is electrolytically processed. Thus, the end point can be reliably detected by monitoring the change in the current or voltage.

  In addition, although the monitor part 38 demonstrated the example which monitors the voltage applied between the process electrode 84 and the electric power feeding electrode 86, or the electric current which flows through this, and detected the process end point, in this monitor part 38, A change in the state of the substrate during processing may be monitored to detect an arbitrarily set processing end point. In this case, the processing end point indicates a point in time when a desired processing amount is reached or a parameter having a correlation with the processing amount reaches an amount corresponding to the desired processing amount for a specified portion of the processing surface. As described above, even during the machining, the machining end point can be arbitrarily set and detected so that the electrolytic machining can be performed in a multistage process.

  For example, detecting changes in frictional force due to differences in the coefficient of friction that occurs when the substrate reaches a different material, or changes in frictional force resulting from removing irregularities when flattening irregularities on the surface of the substrate It is also possible to determine the processing amount and detect the processing end point. In addition, heat generated due to electrical resistance of the work surface and heat generated by collision of ions and water molecules moving in the liquid (pure water) between the work surface and the work surface occurred, for example, deposited on the surface of the substrate. When the copper film is controlled at a constant voltage, the electrolytic processing proceeds, and as the barrier layer and the insulating film are exposed, the electrical resistance increases, the current value decreases, and the amount of heat generation decreases sequentially. Therefore, the processing amount may be determined by detecting the change in the heat generation amount, and the processing end point may be detected. Alternatively, it is also possible to detect a change in the intensity of reflected light due to a difference in reflectance that occurs when a different material is reached, detect the film thickness of the film to be processed on the substrate, and thereby detect the processing end point.

  In addition, an eddy current is generated inside a conductive film such as a copper film, and the eddy current flowing inside the substrate is monitored. For example, a change in frequency or impedance is detected, and the film thickness of the film to be processed on the substrate is determined. It may be detected to detect the processing end point. Further, in the electrolytic machining, the machining rate is determined by the current value flowing between the machining electrode and the feeding electrode, and the machining amount is proportional to the amount of electricity obtained by the product of the current value and the machining time. Therefore, the machining end point may be detected by integrating the amount of electricity obtained by the product of the current value and the machining time, determining that the accumulated value has reached a predetermined value, and determining the machining end point.

  Simultaneously with this electrolytic processing, conditioning by the conditioner 48 of the contact member 40 of the electrode part 42 is performed as needed. That is, the arm 64 of the conditioning unit 50 is moved to move the conditioner 48 attached to the support 66 to the conditioning position above the electrode unit 42. Next, the vertical movement motor 74 is driven, the conditioner 48 is lowered and brought into contact with the contact surface (upper surface) 40a of the contact member 40 of the electrode portion 42 with the substrate W at a predetermined pressure, and simultaneously the rotation motor 76 is driven. Then, the conditioner 48 is rotated (spinned). Thus, the contact surface 40a of the contact member 40 with the substrate W is polished (conditioning) by the conditioner 48 made of a polishing body (fixed abrasive grains) with abrasive grains fixed in the presence of pure water, preferably ultrapure water. I do.

  That is, as described above, pure water, preferably ultrapure water, is supplied to the upper surface of the electrode portion 42. For this reason, the conditioner 48 is brought into contact with the contact surface 40a of the contact member 40 at a predetermined pressure. By relatively moving the contact member 48 and the contact member 40, the contact surface 40a of the contact member 40 with the substrate W can be polished (conditioning) by the conditioner 48.

  Polishing (conditioning) by the conditioner 48 includes contact pressure on the contact surface 40a of the contact member 40 of the conditioner 48, contact amount of the contact member 40 on the contact surface 40a of the conditioner 48, and relative movement between the conditioner 48 and the contact member 40. Can be controlled by speed. The contact pressure and contact amount during conditioning may be arbitrarily changed during conditioning, for example, the contact pressure and contact amount may be reduced during finishing.

Then, after the conditioning is completed, the rotation of the conditioner 48 is stopped, and then the conditioner 48 is raised and the arm 64 is moved to return the conditioner 48 to the original position.
In this example, the contact pressure on the contact surface 40a of the contact member 40 of the conditioner 48 is controlled by the feed amount of the ball screw. However, the conditioner is moved up and down using a cylinder, and the pressure of this cylinder is controlled. May be adjusted to control the contact pressure on the contact surface 40a of the contact member 40, or both may be used in combination.

  After the electrolytic processing is completed, the connection between the processing electrode 84 and the power supply electrode 86 of the power supply 90 is disconnected, the rotation of the substrate holding portion 44 and the electrode portion 42 is stopped, and then the substrate holding portion 44 is raised and the arm 52 is moved. Then, the substrate W is delivered to the transfer robot 36. The transport robot 36 that has received the substrate W transports the substrate W to the reversing machine 32 and reverses it as necessary, transports the substrate W to the cleaning unit 39, performs cleaning and drying, and loads and unloads the dried substrate W. Return to 30 cassettes.

  For example, after the contact member 40 is installed, before the electrolytic processing is performed with the installed contact member 40, after the contact member 40 is replaced, before the electrolytic processing is performed with the contact member 40 after replacement, Alternatively, only the conditioning of the contact member 40 may be performed independently of the electrolytic processing at an interval of the electrolytic processing. In this case, the conditioner 48 is connected to the contact surface 40 a of the contact member 40 while supplying pure water, preferably ultrapure water, to the upper surface of the electrode portion 42 without applying a voltage between the processing electrode 84 and the power supply electrode 86. The conditioner 48 and the contact member 40 are moved relative to each other at a predetermined pressure.

  Here, the pure water supplied to the upper surface of the electrode part 42 during the electrolytic processing (and conditioning) is, for example, water having an electric conductivity (1 atm, converted at 25 ° C., the same applies hereinafter) of 10 μS / cm or less, and is ultrapure. The water is, for example, water having an electric conductivity of 0.1 μS / cm or less. By performing electrolytic processing using pure water or ultrapure water that does not contain an electrolyte in this way, it is possible to prevent the impurities such as the electrolyte from adhering to or remaining on the surface of the substrate W. . Further, since copper ions and the like dissolved by electrolysis are immediately captured by the ion exchange reaction in the contact member 40 made of an ion exchanger, the dissolved copper ions and the like are deposited again on other portions of the substrate W, or oxidized. As a result, the surface of the substrate W is not contaminated.

  In addition, by configuring the conditioner 48 with a polishing body in which the abrasive grains are fixed, the contact member 40 can be conditioned while supplying pure water or ultrapure water, thereby contacting the electrolytic processing of the substrate W. The member 40 can be conditioned at the same time, and the burden of environmental problems can be reduced.

Instead of pure water or ultrapure water, a liquid having an electric conductivity of 500 μS / cm or less, for example, an electrolytic solution obtained by adding an electrolyte to pure water or ultrapure water may be used. By using the electrolytic solution, electric resistance can be reduced and power consumption can be reduced. As this electrolytic solution, for example, a neutral salt such as NaCl or Na ₂ SO ₄ , an acid such as HCl or H ₂ SO ₄ , or an alkali such as ammonia can be used. Depending on the characteristics, it can be appropriately selected and used.

  Furthermore, instead of pure water or ultrapure water, a surfactant or the like is added to pure water or ultrapure water, and the electric conductivity is 500 μS / cm or less, preferably 50 μS / cm or less, more preferably 0. A liquid having a specific resistance of 10 MΩ · cm or less may be used. In this way, by adding a 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 contact member 40. The flatness of the work surface can be improved by reducing the concentration of exchange (dissolution of metal). Here, the surfactant concentration is preferably 100 ppm or less.

  Here, as the contact member (ion exchanger) 40, it is more preferable to use a material excellent in water permeability. By supplying pure water or ultrapure water so as to pass through the contact member 40, sufficient water is supplied to the functional group (sulfonic acid group in the case of a strongly acidic cation exchange material) that promotes the dissociation reaction of water. The amount of dissociation can be increased, and the processing products (including gas) generated by the reaction with hydroxide ions (or OH radicals) can be removed by the flow of water to increase the processing efficiency.

  The ion exchanger which comprises the contact member 40 mentioned above can be comprised with the nonwoven fabric etc. which provided the anion exchange group or the cation exchange group, for example. The cation exchange group preferably has a strong acidic cation exchange group (sulfonic acid group), but may have a weak acidic cation exchange group (carboxyl group). The anion exchange group preferably has a strong basic anion exchange group (quaternary ammonium group), but may have a weak basic anion exchange group (tertiary or lower amino group).

  Here, for example, a nonwoven fabric provided with a strong base anion exchange group is produced by a so-called radiation graft polymerization method in which a polyolefin nonwoven fabric having a fiber diameter of 20 to 50 μm and a porosity of about 90% is irradiated with γ rays and then graft polymerization is performed. The graft chain is introduced, and then the introduced graft chain is aminated to introduce a quaternary ammonium group. The capacity of the ion exchange group to be introduced is determined by the amount of graft chains to be introduced. In order to perform the graft polymerization, for example, using monomers such as acrylic acid, styrene, glycidyl methacrylate, sodium styrenesulfonate, chloromethylstyrene, and the like, by controlling the monomer concentration, reaction temperature, and reaction time, The amount of grafting to be polymerized can be controlled. Therefore, the ratio of the weight after graft polymerization to the weight of the material before 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 nonwoven fabric provided with the strongly acidic cation exchange group was irradiated with γ-rays on a polyolefin nonwoven fabric having a fiber diameter of 20 to 50 μm and a porosity of about 90% in the same manner as the method of providing the strongly basic anion exchange group. The graft chain is introduced by a so-called radiation graft polymerization method in which post-graft polymerization is performed, and then the introduced graft chain is treated with, for example, heated sulfuric acid to introduce a sulfonic acid group. Moreover, a phosphoric acid group can be introduce | transduced if it processes with the heated phosphoric acid. Here, the graft ratio can be 500% at the maximum, and the ion exchange group introduced after the graft polymerization can be 5 meq / g at the maximum.

  In addition, as a material of the raw material of the contact member (ion exchanger) 40, polyolefin-type polymers, such as polyethylene and a polypropylene, or other organic polymers are mentioned. Moreover, as a raw material form, a woven fabric, a sheet | seat, a porous material, a short fiber, etc. other than a nonwoven fabric are mentioned. Here, polyethylene and polypropylene can be subjected to graft polymerization by generating radicals in the material by first irradiating the material with radiation (γ rays and electron beams) (pre-irradiation) and then reacting with the monomer. . Thereby, a graft chain having high uniformity and few impurities can be formed. On the other hand, other organic polymers can be radically polymerized by impregnating the monomer and irradiating (simultaneously irradiating) radiation (γ rays, electron beams, ultraviolet rays). In this case, it is not uniform, but can be applied to most materials.

  In this way, the contact member (ion exchanger) 40 is composed of a nonwoven fabric provided with an anion exchange group or a cation exchange group, so that liquid such as pure water, ultrapure water, or an electrolytic solution can freely move inside the nonwoven fabric. Thus, it becomes possible to easily reach the active point having a water decomposition catalytic action inside the nonwoven fabric, and many water molecules are dissociated into hydrogen ions and hydroxide ions. Furthermore, since the hydroxide ions generated by the dissociation are efficiently carried with the movement of liquid such as pure water, ultrapure water, or electrolytic solution, a high current can be obtained even at a low applied voltage.

  Here, if the contact member (ion exchanger) 40 is composed only of an anion exchange group or a cation exchange group, not only the work material that can be electrolytically processed but also impurities are generated depending on the polarity. It becomes easy. Therefore, an anion exchanger having an anion exchange group and a cation exchanger having a cation exchange group are overlapped, or both the anion exchange group and the cation exchange group are added to the ion exchange group itself. As a result, the range of the material to be processed can be expanded, and impurities can be hardly generated.

  The present invention can be applied to various electrolytic processing apparatuses, and various combinations of processing liquids and contact members can be applied. In addition to the ion exchanger, for example, a member having an electrolyte may be configured with a ceramic impregnated material holding an electrolytic solution therein. Further, as the contact member, an insulator or a conductive pad, or an arbitrary combination of these and a member having an electrolyte may be used.

  According to this example, the contact surface 40a of the contact member 40 that contacts the substrate W at the time of electrolytic processing is applied to the conditioning unit 50 so that the flatness and the surface roughness are not more than predetermined values. By conditioning through the conditioner 48, variations in the state (flatness and surface roughness) of the contact surface 40a of the contact member 40 with the substrate W before and after replacement and use of the contact surface 40a of the contact member 40 with the substrate W are used. It is possible to prevent a change in the state of the contact surface 40a of the contact member 40 with the substrate W due to deterioration accompanying the above. As a result, the contact state of the contact member 40 on the surface of the substrate W can be kept constant, and the processing characteristics in the electrolytic processing can be stabilized and the life of the contact member 40 can be extended.

  FIG. 7 shows an electrolytic processing apparatus according to another embodiment of the present invention. The electrolytic processing apparatus shown in FIG. 7 is different from the electrolytic processing apparatus shown in FIGS. 4 and 5 in that the conditioning unit 50 is omitted and the polishing body is formed in a shape substantially the same as that of the substrate W, for example, with a fixed abrasive. A conditioner 96 is prepared separately so that the substrate holding part 44 can selectively hold the substrate W and the conditioner 96.

  That is, in this example, the substrate W is held by the substrate holding unit 44 and the substrate W held by the substrate holding unit 44 is supplied to the contact member 40 of the electrode unit 42 while supplying pure water or the like to the upper surface of the electrode unit 42. The substrate W and the electrode part 42 are moved relative to each other while being brought into contact with each other. At the same time, electrolytic processing is performed by applying a predetermined voltage between the processing electrode 84 and the feeding electrode 86 by the power supply 90. Then, the conditioner 96 is held by the substrate holding unit 44 and the conditioner 96 held by the substrate holding unit 44 is brought into contact with the contact member 40 of the electrode unit 42 with a predetermined pressure while supplying pure water or the like to the upper surface of the electrode unit 42. In addition, the contact member 40 is conditioned (polished) by relatively moving the substrate W and the electrode portion 42.

  According to this example, conditioning of the contact member 40 cannot be performed simultaneously with the electrolytic processing of the substrate W. For example, after the contact member 40 is installed, before the electrolytic processing is performed with the installed contact member 40, After the contact member 40 is replaced, before the electrolytic processing is performed with the replaced contact member 40, and further, at the interval of the electrolytic processing, only the conditioning of the contact member 40 is performed independently of the electrolytic processing. By omitting the part, the structure can be simplified.

It is a figure which shows one manufacture example of a copper wiring board in order of a process. Based on the principle of electrolytic processing in which a machining electrode and a feeding electrode are brought close to a substrate (workpiece) and a liquid such as pure water is supplied between the machining electrode and the feeding electrode and the substrate (workpiece) to perform electrolytic machining. It is a figure attached to description. It is a top view which shows the structure of the substrate processing apparatus provided with the electrolytic processing apparatus in embodiment of this invention. It is a vertical front view which shows typically the electrolytic processing apparatus shown in FIG. FIG. 5 is a plan view of FIG. 4. (A) is the graph which shows the relationship between the electric current which flows when the surface of the board | substrate which formed the different material into a film is electrolytically processed, and time, (b) is the graph which respectively shows the relationship between the applied voltage and time. . It is a vertical front view which shows typically the electrolytic processing apparatus of other embodiment of this invention.

Explanation of symbols

30 Loading / Unloading Section 32 Reversing Machine 34 Electrolytic Processing Device 38 Monitor Section 39 Cleaning Section 40 Contact Member (Ion Exchanger)
40a Contact surface 42 Electrode unit 44 Substrate holding unit 46 Electrolytic processing unit 48, 96 Conditioner 48a Polishing surface 50 Conditioning unit 52, 64 Arm 54, 68 Oscillating motor 56, 70 Oscillating shaft 58, 72 Ball screw 60, 74 For vertical movement Motors 62, 76 Motor for rotation 66 Support body 80 Table 80a Through hole 82 Hollow motor 84 Processing electrode 86 Feed electrode 90 Power source 92 Pure water supply pipe 94 Pure water nozzle

Claims (15)

A machining electrode that is freely accessible to the workpiece;
A feeding electrode for feeding power to the workpiece;
A contact member that is disposed on at least one of the workpiece and the processing electrode or the power feeding electrode and is freely contactable with the workpiece;
A power source for applying a voltage between the machining electrode and the power supply electrode;
A drive unit that relatively moves the workpiece and at least one of the processing electrode or the feeding electrode;
A fluid supply unit that supplies fluid to at least one of the workpiece and the processing electrode or the power supply electrode;
An electrolytic processing apparatus comprising: a conditioning unit including a conditioner that contacts a contact surface of the contact member with the workpiece to condition the contact surface. A machining electrode that is freely accessible to the workpiece;
A feeding electrode for feeding power to the workpiece;
A contact member that is disposed on at least one of the workpiece and the processing electrode or the power feeding electrode and is freely contactable with the workpiece;
A power source for applying a voltage between the machining electrode and the power supply electrode;
A drive unit that relatively moves the workpiece and at least one of the processing electrode or the feeding electrode;
A fluid supply unit that supplies fluid to at least one of the workpiece and the processing electrode or the power supply electrode;
An electrolytic processing apparatus comprising: a conditioner that contacts a contact surface of the contact member with the workpiece and conditioning the contact surface; and a holding portion that selectively holds one of the workpieces.   The electrolytic processing apparatus according to claim 1, wherein the contact member is formed of a member including an electrolyte, an insulator, or any combination thereof.   The electrolytic processing apparatus according to claim 3, wherein the electrolyte is made of a solid electrolyte.   The electrolytic processing apparatus according to claim 4, wherein the solid electrolyte is made of an ion exchanger.   The electrolytic processing apparatus according to claim 1, wherein the contact member is formed of a conductive pad and is disposed between the workpiece and the processing electrode or the power supply electrode.   The electrolytic processing apparatus according to claim 1, wherein at least a portion of the conditioner that comes into contact with the contact surface of the contact member is made of a polishing body to which abrasive grains are fixed.   The electrolytic processing apparatus according to claim 7, wherein a flatness of a polishing surface that contacts a contact surface of the contact member of the polishing body is 100 μm or less, and a diameter of the abrasive grains is 5 μm or less.   The electrolytic processing apparatus according to claim 1, wherein the conditioner includes a polishing pad that performs polishing using loose abrasive grains.   The electrolytic processing apparatus according to claim 9, wherein a diameter of the loose abrasive is 5 μm or less. A conditioner is brought into contact with the contact surface of the contact member that performs electrolytic machining in contact with the workpiece,
A contact member conditioning method, wherein the contact member is conditioned by relatively moving the contact member and the conditioner in the presence of a liquid.   12. The method for conditioning a contact member according to claim 11, wherein the conditioning of the contact member is performed at an interval of electrolytic processing after the installation or replacement of the contact member or simultaneously with electrolytic processing of the workpiece. Hold the conditioner with a holding part that holds the work piece in a removable manner.
Contacting the conditioner with the contact surface with the workpiece of a contact member that performs electrochemical machining in contact with the workpiece;
A contact member conditioning method, wherein the contact member is conditioned by relatively moving the contact member and the conditioner in the presence of a liquid.   14. The method for conditioning a contact member according to claim 13, wherein the conditioning of the contact member is performed after the contact member is installed or replaced, or at an interval of electrolytic processing.   The conditioning of the contact member reduces the flatness of the contact surface of the contact member with the workpiece to 100 μm or less and the surface roughness of the contact surface to 5 μm or less. A method for conditioning a contact member as described.