JP2010087338A - Method and apparatus for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently form a Cu wiring structure, by preventing a poisoning defect due to re-adhesion of particles to a wafer in cleaning after Cu-CMP from occurring, which has been a problem. <P>SOLUTION: This method of manufacturing a semiconductor device of a multilayered wiring structure including upper-layer wiring, lower-layer wiring and vias connecting the upper-layer wiring to the lower-layer wiring includes processes of: forming a trench and thereafter forming a conductive film containing copper on the upper surface of a low-permittivity film; forming the lower-layer wiring in the trench by chemically and mechanically polishing the conductive film; cleaning a substrate after the chemical and mechanical polishing; and executing a reduction treatment by ammonium plasma to the upper surface of the low-permittivity film to form a diffusion prevention film thereon. The cleaning process executes two or more stages of cleaning, wherein brush scrub cleaning is executed using an organic acid cleaning chemical in the first stage, and cleaning is executed using an organic alkaline cleaning chemical in the second stage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the manufacture of semiconductor devices, and more particularly to a technique for improving a method for cleaning a wafer after chemical mechanical polishing (CMP).

  As a result of high integration and miniaturization of semiconductor devices (semiconductor devices), the semiconductor devices are made into multi-layer wiring, the introduction of Cu and low dielectric constant (Low-k) materials in the wiring material, and the narrow pitch of the wiring structure Is progressing.

  Hereinafter, as an example, a manufacturing method of a multilayer wiring process (dual damascene process) of Cu wiring will be described. FIG. 13 shows an example of a manufacturing method of a Cu wiring process in a semiconductor device having a multilayer wiring structure after a 90 nm device.

  First, as shown in FIG. 13A, a predetermined depth (for example, 300 nm) is formed on the upper surface of the first low dielectric constant film 1 having a predetermined film thickness (for example, 600 nm) formed on a silicon substrate. ) Is opened. For example, a carbon-containing silicon oxide film (SiOC film) is used as the low dielectric constant film. Next, a first barrier metal film 2 composed of Ta and TaN and a Cu electrode film (also referred to as a Cu seed film, not shown) for electrolytic plating are formed in this order from the lower layer by sputtering. The Further, the Cu film 3 is deposited from the first barrier metal film 2 or the Cu electrode film to a predetermined film thickness (for example, 600 nm) by electrolytic plating.

  Thereafter, the Cu film 3 other than the first trench and the first barrier metal film 2 are removed by Cu-CMP (chemical mechanical polishing for the Cu film), as shown in FIG. Then, the first trench wiring 4 in which Cu is embedded in the first trench is formed.

  Next, as shown in FIG. 13C, a reduction process using ammonia plasma is performed on the first trench wiring 4, and a predetermined film thickness (for example, for example, on the first trench wiring 4) 50 nm) is formed. The first diffusion preventing film 5 is a film for preventing Cu in the first trench wiring 4 from diffusing into a second low dielectric constant film 6 described later, for example, a silicon carbonitride film (SiCN film) is used.

  Further, as shown in FIG. 13D, a second low dielectric constant film 6 having a predetermined film thickness (for example, 600 nm) is formed on the first diffusion preventing film 5. Further, an antireflection film 7 made of an organic material is applied on the second low dielectric constant film 6. When the via hole is formed in the second low dielectric constant film 6, the antireflection film 7 suppresses reflected light from the first trench wiring 4 serving as a base layer in a photolithography process described later, thereby forming a via hole. Prevent defects. Further, a first chemically amplified resist 8 is applied on the antireflection film 7, and photolithography is performed using a predetermined mask, so that the first chemically amplified resist 8 is resolved.

  Next, as shown in FIG. 13E, the second low dielectric constant film 6 is removed from the upper surface of the second low dielectric constant film 6 to the upper surface of the first diffusion prevention film 5 by dry etching. Then, the first via hole 9 is opened.

  Subsequently, as shown in FIG. 13F, a second antireflection film 10 made of an organic material is embedded on the second low dielectric constant film 6 in which the first via hole 9 is opened. Then, the second chemically amplified resist 11 is applied, and the second chemically amplified resist 11 is resolved through a photolithography process using a predetermined mask.

  Next, as shown in FIG. 13G, a first depth having a predetermined depth (for example, 300 nm) is formed on the first via hole 9 formed in the second low dielectric constant film 6 by dry etching. Two trenches 12 are opened.

  Thereafter, as shown in FIG. 13H, the entire surface is etched back, the diffusion preventing film 5 existing on the bottom surface of the first via hole 9 is removed, and the surface of the first trench wiring 4 is exposed.

  Furthermore, as shown in FIG. 13 (i), a second barrier metal film 13 made of Ta and TaN by a sputtering method, a Cu electrode film (Cu seed film, not shown) for electrolytic plating, and Is deposited. Next, the Cu film 14 is embedded in the first via hole 9 and the second trench 12 by electrolytic plating.

  Thereafter, as shown in FIG. 13 (j), the Cu film 14 other than the first via hole 9 and the second trench 12 and the second barrier metal film 13 are removed by Cu-CMP. Two trench wirings 15 are formed.

  By repeating the above manufacturing process, a semiconductor device having a multilayer wiring structure of Cu wiring can be manufactured.

  However, when the manufacturing method is employed, there is a problem that poisoning failure occurs when photolithography is performed. Poisoning failure means that a resolution failure (pattern formation failure) of a chemically amplified resist occurs. Poisoning failure occurs by the following procedure. As described above, after the trench wiring is formed by Cu-CMP, reduction treatment by ammonia plasma is performed on the low dielectric constant film. At this time, the methyl group and the ammonia radical in the low dielectric constant film are combined. An amine (base) is generated on the low dielectric constant film. After the amine is generated, a low dielectric constant film and a via hole are newly formed in order to form a new Cu wiring on the upper layer, a chemically amplified resist is applied, and photolithography is performed. In this case, since the amine remains in the underlayer provided below the chemically amplified resist, the amine diffuses from the underlayer during the photolithography process and enters the chemically amplified resist. The infiltrated amine neutralizes the acid generated in the chemically amplified resist by exposure and weakens the chemical amplification action when forming the resist pattern. As a result, poor resolution (pattern formation failure) of the chemically amplified resist occurs.

  For the purpose of solving the problem, Japanese Patent Application Laid-Open No. 2006-73569 (Patent Document 1) discloses a technique for forming a film containing Si, C, and N by supplying a gas onto a substrate. ing. In this technique, the gas is composed of at least a raw material gas and an inert gas, and a gas containing Si partially bonded to an organic group is used as one of the raw material gases. The film is formed by setting the flow ratio of the gas containing Si and the inert gas to 1: 4.2 or more. According to this configuration, it is possible to suppress the release of amine from the diffusion preventing film (SiCN film) and to suppress the occurrence of poor poisoning.

  On the other hand, when a method for manufacturing a semiconductor device is employed, there is a problem in that the semiconductor device malfunctions and reliability is reduced. The problem occurs in the following procedure.

  In the manufacturing method, Cu-CMP, which is a process for removing unnecessary Cu film and barrier metal film other than Cu wiring, is an indispensable process. Contaminants (hereinafter referred to as particles) such as foreign substances, molecular organic components, slurry residues, mobile ions, and metals adhere to the wafer surface after this Cu-CMP. It is necessary to carry out a cleaning process. However, even if the cleaning process is performed, particles may remain on the wafer surface, and the particles cause a malfunction of the semiconductor device and a decrease in reliability. Therefore, in the wafer cleaning process after Cu-CMP, particles on the wafer are efficiently removed, excessive etching of the oxide film on the wafer surface and microroughness of the Cu wiring (geometry of nanometer size formed on the thin film surface). It is necessary to prevent the target shape).

For example, Japanese Patent Laid-Open No. 11-330023 (Patent Document 2) discloses that after a copper film is formed on the surface of a wafer including an interlayer insulating film, a chemical mechanical polishing process is performed using an abrasive containing an oxidizing agent. The technique about the process of wash | cleaning a thing is disclosed. In this technique, the wafer is cleaned by combining the first-stage particle removal process in an alkali or hydrogen reducing atmosphere and the second-stage process in an acid atmosphere in this order. With this configuration, it is possible to effectively remove and prevent contamination by various metals including adhesion of Cu and W to other than the Cu wiring without damaging the Cu wiring, W plug and barrier metal film. It is said.
JP 2006-73569 A Japanese Patent Laid-Open No. 11-330023

  However, although the technique described in Patent Document 1 can prevent the occurrence of poor poisoning, it must handle a gas composed of a raw material gas and an inert gas, which makes the operation of the manufacturing process complicated and expensive. There is a problem of becoming.

  Furthermore, in the technique described in Patent Document 2, in the cleaning process after Cu-CMP, particles on the Cu wiring may not be completely removed, and poisoning defects may be caused due to particles remaining on the Cu wiring. There is a problem that occurs. As described above, amines that cause poisoning defects are present in and on the low dielectric constant film. Therefore, if a diffusion prevention film is formed on the surface of the Cu wiring with a small amount of particles remaining on the surface, a diffusion prevention film is formed on the particles at the particle portion. Will be formed. In the floating portion of the diffusion prevention film, since the diffusion prevention film is thin, a hole communicating with the low dielectric constant film may be formed in the diffusion prevention film. When such a hole is formed in the diffusion prevention film, the amine present in the low dielectric constant film and on the surface passes through the hole and diffuses and penetrates into the chemically amplified resist, resulting in poor poisoning. .

  Furthermore, in the cleaning process after Cu-CMP, for example, a PVA brush is used. The PVA brush is a cylindrical brush made of a sponge made of polyvinyl alcohol resin and having a cylindrical protrusion disposed on the surface. When this PVA brush is used for wafer cleaning, there is a problem of causing reattachment of particles. In other words, during the cleaning process, when a PVA brush is used, particles existing on the wafer adhere to the PVA brush and are temporarily removed from the Cu wiring. However, after the cleaning process is completed, when the PVA brush is detached from the wafer, the particles attached to the PVA brush reattach to the Cu wiring of the wafer. The reattached particles cause poor poisoning for the reasons described above.

  Therefore, the present invention suppresses poisoning defects by preventing re-adhesion of particles on the Cu wiring in the cleaning process after Cu-CMP, thereby improving the yield of the semiconductor device and the semiconductor manufacturing. An object is to provide an apparatus.

  In order to solve the above-described problems and achieve the object, a manufacturing method of a semiconductor device according to the present invention has a multilayer wiring structure including an upper layer wiring, a lower layer wiring, and a via connecting the upper layer wiring and the lower layer wiring. A manufacturing method of a semiconductor device is provided. In the manufacturing method, a step of forming a trench on the upper surface of the low dielectric constant film formed on the substrate, and a step of forming a conductive film containing copper on the upper surface of the low dielectric constant film after the formation of the trench And a step of chemically and mechanically polishing the conductive film to form a lower layer wiring in the trench. Further, the manufacturing method includes a step of cleaning the substrate after the chemical mechanical polishing, and after the cleaning of the substrate, a reduction treatment with ammonia plasma is performed on the upper surface of the low dielectric constant film, and diffusion is performed thereon. A step of forming a prevention film, a step of forming an interlayer insulation film on the diffusion prevention film, and a step of opening a via hole corresponding to a via in the interlayer insulation film above the lower layer wiring are performed. Next, the manufacturing method includes a step of embedding an antireflection film in the via hole, a step of applying a chemically amplified resist on the upper surface of the antireflection film, and forming a resist pattern corresponding to the trench of the upper wiring by photolithography Including. The cleaning process is performed in at least two stages, the first stage performs brush scrub cleaning using an organic acid cleaning chemical, and the second stage performs cleaning using an organic alkaline cleaning chemical. Is done.

The low dielectric constant film corresponds to, for example, a carbon-containing silicon oxide film (SiOC film). For example, a silicon carbonitride film (SiCN film) corresponds to the diffusion prevention film. The organic acid cleaning chemical is a cleaning chemical prepared using an organic acid. For example, oxalic acid, malonic acid, succinic acid, tartaric acid, malic acid, citric acid and the like can be used. An organic alkali cleaning chemical is a cleaning chemical prepared using an organic alkali obtained by adding a chelating agent to an alkaline cleaning agent. For example, gluconate, EDTA (ethylenediaminetra
Aqueous acid: ethylenediaminetetraacetic acid), HEDTA (N- (2-hydroxyethyl) ethyleneditriotropic acid), aqueous ammonia to which a chelating agent such as phosphonate is added can be used.

  Brush scrub cleaning is cleaning that removes particles adhering to the substrate by providing a pair of rotating brushes so as to contact both surfaces of the substrate and rotating the pair of rotating brushes. For example, brush scrub cleaning is performed while the substrate is maintained in a substantially vertical posture. The substrate may be kept in a substantially horizontal posture.

  The first stage of the cleaning process performs brush scrub cleaning using an organic acid cleaning chemical solution having a pH of 3 to 4, and the second stage of the cleaning process includes organic alkali cleaning having a pH of 9 to 10. It can comprise so that it may wash | clean using a chemical | medical solution.

  The first stage of the cleaning step includes a step of rotating a substrate on which brush scrub cleaning is performed, and a rotation number corresponding to the rotation of the substrate every predetermined period when the substrate starts rotating. A step of detecting and a step of determining whether or not the detected number of rotations is included within a predetermined range are executed. Further, the first stage of the cleaning step may include a step of stopping brush scrub cleaning of the substrate when the detected number of rotations is outside a predetermined range as a result of the determination. For example, in the case of a configuration that measures the number of rotations of the rotating unit that rotates the substrate and the number of rotations corresponding to the rotation of the substrate whose rotation is transmitted by the rotating unit, the predetermined range is the rotation corresponding to the rotation of the substrate. The number is in the range of the number of rotations that is equivalent to the number of rotations of the rotating part.

  On the other hand, in another aspect, the present invention can also provide a semiconductor manufacturing apparatus that performs two-stage cleaning. The semiconductor manufacturing apparatus performs chemical mechanical polishing on a substrate having a conductive film containing copper formed on an upper surface of a low dielectric constant film, and forms a lower layer wiring in which the conductive film is embedded in a trench. A semiconductor manufacturing apparatus including a polishing unit to be formed and a cleaning unit that performs cleaning on the substrate on which the chemical mechanical polishing is performed is assumed. In the semiconductor manufacturing apparatus, the cleaning unit includes a first cleaning unit that performs brush scrub cleaning using an organic acid cleaning chemical, and a second cleaning unit that performs cleaning using an organic alkaline cleaning chemical. can do.

  The first cleaning unit performs brush scrub cleaning using an organic acid cleaning chemical having a pH of 3 to 4, and the second cleaning unit performs cleaning using an organic alkaline cleaning chemical having a pH of 9 to 10. Can be configured to do.

  Further, the first cleaning unit detects a rotation number corresponding to the rotation of the substrate every predetermined period when the rotation unit that rotates the substrate on which brush scrub cleaning is performed and the rotation of the substrate starts. A detection unit; and a determination unit that determines whether or not the detected number of rotations is included in a predetermined range. Furthermore, the first cleaning unit may be configured to include a stop unit that stops brush scrub cleaning of the substrate when the detected number of rotations is outside a predetermined range as a result of the determination. The detection unit may directly measure the number of rotations of the rotating substrate, or may measure the number of rotations of a rotating body that is rotated by the rotation of the substrate.

  According to the semiconductor device manufacturing method of the present invention, the cleaning step performs at least two stages of cleaning, the first stage performs brush scrub cleaning using an organic acid cleaning chemical, and the second stage includes Cleaning is performed using an organic alkali cleaning chemical.

  Thereby, in the first stage, since the cleaning chemical used in the brush scrub cleaning is an organic acid, both the lower wiring containing copper and the particles have a negative potential. Therefore, it is possible to prevent particles from adhering to the lower layer wiring, or particles adhering to the brush from re-adhering to the lower layer wiring. Furthermore, in the second stage, since cleaning is performed using an organic alkali cleaning chemical solution, both the lower layer wiring and the particles have a negative potential, and it is possible to appropriately remove the particles remaining on the lower layer wiring. . Further, since the organic alkali cleaning chemical solution etches the surface of the lower layer wiring, even if particles remain on the surface of the lower layer wiring, the particles can be appropriately removed. As a result, after cleaning, for example, even if reduction treatment or photolithography is performed, it is possible to appropriately prevent poisoning defects caused by particles reattached on the lower layer wiring and to improve the yield of the semiconductor manufacturing apparatus. It becomes possible.

  The first stage of the cleaning process performs brush scrub cleaning using an organic acid cleaning chemical solution having a pH of 3 to 4, and the second stage of the cleaning process includes organic alkali cleaning having a pH of 9 to 10. It can comprise so that it may wash using a chemical | medical solution.

  Thereby, in the first stage, brush scrub cleaning is performed in a state where both the lower-layer wiring containing copper and the particles surely have a negative potential. Further, even in the second stage, cleaning is performed in a state where the lower layer wiring and the particles surely have a negative potential. Therefore, it is possible to minimize the possibility of particles remaining on the lower layer wiring in the cleaning process after Cu-CMP, thereby minimizing the occurrence of poisoning defects and improving the yield of semiconductor manufacturing equipment. It becomes.

  The first stage of the cleaning step includes a step of rotating a substrate on which brush scrub cleaning is performed, and a rotation number corresponding to the rotation of the substrate every predetermined period when the substrate starts rotating. A step of detecting, a step of determining whether or not the detected number of rotations is included in a predetermined range, and a brush on the substrate when the detected number of rotations is not included in the predetermined range as a result of the determination And a step of stopping the scrub cleaning.

  Thereby, in the first stage, it is determined whether or not the brush is uniformly in contact with the substrate, and if the brush is not uniformly in contact with the substrate, the brush scrub cleaning of the substrate is stopped. . Therefore, it becomes possible to reliably prevent the reattachment of particles to the lower layer wiring, which frequently occurs when the brush is not uniformly in contact with the substrate. Furthermore, when the brush is not in uniform contact with the substrate, it is possible to stop performing the brush scrub cleaning on the substrate. As a result, it is possible to appropriately prevent poisoning defects caused by the particles reattached on the lower layer wiring and improve the yield of the semiconductor manufacturing apparatus.

  Of course, the semiconductor manufacturing apparatus according to the present invention has the same effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the present invention is embodied by a method for manufacturing a semiconductor device having a multilayer wiring of Cu wiring on a wafer (substrate). In the manufacturing method, the chemical mechanical polishing is not limited to the first method using a standard polishing pad and floating abrasive grains, but the second method using fixed abrasive grains, or the first method. And an intermediate method between the second method and the second method.

<First embodiment>
FIG. 1 is a schematic configuration diagram showing a Cu-CMP apparatus according to a first embodiment of the present invention. In the following description, the vertical direction in FIG. 1 is referred to as the front-rear direction of the Cu-CMP apparatus 10, and the horizontal direction in FIG.

  As shown in FIG. 1, the Cu-CMP apparatus 10 of this embodiment includes a polishing unit 2 that polishes a wafer and a cleaning unit 3 that cleans the wafer polished by the polishing unit 2. The cleaning unit 3 is provided adjacent to the polishing unit 2, and a wet robot R <b> 2 that carries a wafer between the polishing unit 2 and the cleaning unit 3 is disposed adjacent to the polishing unit 2 and the cleaning unit 3. ing. The wet robot R2 transports the wafer received from the dry robot R1 described later to the polishing unit 2 and transports the wafer subjected to chemical mechanical polishing by the polishing unit 2 to the cleaning unit 3.

  Further, the polishing unit 2, the cleaning unit 3, and a plurality of load port groups (for example, load ports LP 1, LP 2, LP 3, LP 4) are arranged in series with respect to the front-rear direction of the Cu-CMP apparatus 10. Each load port LP 1, LP 2, LP 3, LP 4 is arranged in series with respect to the left-right direction of the Cu-CMP apparatus 10. In the plurality of load ports LP1, LP2, LP3, and LP4, containers such as FOUP (Front Opening Unified Pod) containing a plurality of wafers are detachably loaded and arranged. Further, there is a dry robot R1 that carries a wafer between the wet robot R2 and the plurality of load ports LP1, LP2, LP3, LP4 and between the cleaning unit 3 and the plurality of load ports LP1, LP2, LP3, LP4. , Adjacent to the load ports LP 1, LP 2, LP 3, LP 4, the wet robot R 2 and the cleaning unit 3. The dry robot R1 carries out a predetermined unprocessed wafer from a container installed in the load ports LP1, LP2, LP3, LP4, and transports the unprocessed wafer to the wet robot R2. Further, the dry robot R1 carries out a dried wafer from a drying unit D1 described later, and carries the dried wafer into containers installed in the load ports LP1, LP2, LP3, and LP4.

  In the polishing unit 2, three polishing platens (first layers) are used to polish a metal film (here, an adhesion layer made of TaN, a barrier metal film made of Ta, and a Cu film) deposited on the wafer in stages. A polishing platen P1, a second polishing platen P2, and a third polishing platen P3 are provided). Wafers as workpieces are sequentially transferred and arranged on the three polishing platens and subjected to chemical mechanical polishing. For example, the unprocessed wafer is transferred to the first polishing platen P1, and the Cu film on the wafer is polished to a predetermined depth. Next, the wafer polished to a predetermined depth is transferred to the second polishing platen P2, and the Cu film on the wafer is polished from the polished surface to the upper surface of the barrier metal film. Further, the wafer polished to the upper surface of the barrier metal film is transferred to the third polishing platen P3, and the barrier metal film and the adhesion layer on the wafer are polished. In the third polishing platen P3, in order to completely remove the barrier metal film and the adhesion layer, overpolishing is performed so that the low dielectric constant film under the adhesion layer is exposed.

  In addition to the three polishing platens, the polishing unit 2 is loaded with an unpolished wafer transferred from the wet robot R2 or a polished wafer transferred from the third polishing platen P3. Is provided.

  Wafer transfer between the three polishing platens P1 to P3 and the load / unload unit U1 is performed by heads H1 to H4 (also referred to as carriers) connected to the wafer rotation mechanism unit X1. The wafer rotation mechanism portion X1 is formed of a cross shape having four arms extending radially at an equal angle with respect to the center, and is provided to be rotatable in a horizontal plane with the center of the cross shape as a rotation axis. The rotation axis of the wafer rotation mechanism unit X1 is configured to be perpendicular to the machine floor of the polishing unit 2 installed horizontally. Three polishing platens P <b> 1 to P <b> 3 and a load / unload unit U <b> 1 are disposed on the same circumference around the rotation axis of the wafer rotation mechanism unit X <b> 1. Each of the heads H1 to H4 has a configuration capable of independently performing a lifting operation and a rotation operation in a plane parallel to the polishing platens P1 to P3.

  The cleaning unit 3 includes a plurality of cleaning units that clean the Cu-CMP wafer in stages. The cleaning unit 3 includes a cleaning unit receiving unit CIN, a first cleaning unit C1 that performs brush scrub cleaning using an organic acid cleaning chemical, a second cleaning unit C2 that performs cleaning using an organic alkaline cleaning chemical, and a drying that performs drying. The unit D1 is arranged in series with respect to the left-right direction of the Cu-CMP apparatus 10. Further, the cleaning unit 3 includes a robot R3 provided to be movable along the cleaning unit receiving unit CIN, the first cleaning unit C1, the second cleaning unit C2, and the drying unit D1.

  When the wet robot R2 transports the Cu-CMP wafer to the cleaning unit receiving unit CIN, the robot R3 transfers the wafer stored in the cleaning unit receiving unit CIN to the first cleaning unit C1, the second cleaning unit C2, and the drying unit. Transport in the order of D1.

  The first cleaning unit C1 and the second cleaning unit C2 constitute independent units, perform cleaning using separate cleaning chemicals, and perform two-stage cleaning on the wafer after Cu-CMP. . In the drying unit D1, a drying process is performed on the cleaned wafer (for example, a wafer that has been cleaned by the first cleaning unit C1 and the second cleaning unit C2).

  A control unit 100 is connected to the Cu-CMP apparatus 10, and the control unit 100 controls the polishing unit 2 and the cleaning unit 3 described above.

  FIG. 2 is a diagram illustrating a main configuration of the first cleaning unit C1 in the cleaning unit 3 of the Cu-CMP apparatus 10 according to the first embodiment of the present invention. 2 corresponds to the downward direction in FIG. 1, and the right direction of the first cleaning unit C1 in FIG. 2 corresponds to the right direction in FIG.

  As shown in FIG. 2, the first cleaning unit C1 is a rectangular parallelepiped, the wafer W after Cu-CMP is maintained in a posture substantially perpendicular to the machine floor, and the wafer W is the first cleaning unit C1. The wafer W is configured to be stored from above the first cleaning unit C1 in a state perpendicular to the front surface. Two pulleys (a front pulley P1 and a rear pulley P2) are provided on the front and rear sides of the inside of the first cleaning unit C1 at an interval narrower than the diameter of the wafer W to be stored. The two pulleys P1 and P2 support the wafer W stored from above the first cleaning unit C1 from below. The two pulleys P1 and P2 have the same radius, and the rotation axes P1a and P2a are both orthogonal to the surface of the stored wafer W. In other words, the rotation axes P1a and P2a of the two pulleys P1 and P2 are orthogonal to the right side surface of the first cleaning unit C1. A motor (not shown) is connected to each of the two pulleys P1 and P2, and is configured to rotate, for example, at 50 rpm (revolutions per minute) counterclockwise with respect to the rotation axes P1a and P2a when viewed from the right side. The When the two pulleys P1 and P2 support the wafer W and rotate at 50 rpm counterclockwise with respect to the respective rotation axes P1a and P2a when viewed from the right side, the rotation is transmitted to the wafer W, and the wafer W Is rotated at a predetermined number of rotations counterclockwise when viewed from the right side with respect to the rotation axis Wa parallel to the rotation axes P1a and P2a of the two pulleys P1 and P2. The predetermined rotational speed is determined, for example, by multiplying the ratio of the diameter of the pulley to the diameter of the wafer W by the rotational speed of the pulley. Specifically, assuming that the ratio of the diameter of the pulley to the diameter of the wafer W is 1/10 and the rotation speed of the pulley is 500 rpm, the predetermined rotation speed is 50 rpm.

  In the first cleaning unit C1 according to the first embodiment of the present invention, two pulleys that transmit rotation to the wafer W are provided. However, rotation axes that are parallel to the rotation axes P1a and P2a of the pulleys are provided. The number of pulleys that support the wafer W may be further increased.

  A first PVA brush B1 (left PVA brush) and a second PVA brush B2 (right PVA brush) are provided on the left and right sides of the first cleaning unit C1. The first PVA brush B1 and the second PVA brush B2 can be brought into contact with and separated from both surfaces (front and back surfaces) of the wafer W supported by two pulleys P1 and P2 and substantially perpendicular to the machine floor. Composed. Both ends of the first PVA brush B1 and the second PVA brush B2 are supported by sliders (not shown) that can move in parallel in the left-right direction of the first cleaning unit C1, so that the contact and separation are possible. Yes.

  Each of the first PVA brush B1 and the second PVA brush B2 has a cylindrical shape (roll shape). The first PVA brush B1 is arranged at a position that is parallel to the surface of the wafer W in which the rotation axis B1a of the first PVA brush B1 is housed and is in contact (contact) with the center of the wafer W. . Further, the second PVA brush B2 is located at a position where the rotation axis B2a of the second PVA brush B2 faces the rotation axis B1a of the first PVA brush B1 across the wafer W, with respect to the surface of the wafer W. They are arranged in parallel and at a position where they contact (abut) the center of the wafer W. Therefore, the first PVA brush B1 and the second PVA brush B2 are in a state of just sandwiching the wafer W. Cleaning the wafer with such a pair of rotating brushes is called brush scrub cleaning.

  Of the two PVA brushes B1 and B2, one PVA brush (for example, the first PVA brush B1) is on the surface of the wafer W, and the other PVA brush (for example, the second PVA brush B2) is on the wafer W. Clean the back of the. When the two PVA brushes B1 and B2 clean the wafer W, the rotational speed of the two PVA brushes B1 and B2 is set to 300 rpm, for example. The rotation direction is a direction in which the wafer W substantially perpendicular to the machine floor is swept downward, in other words, a direction in which the wafer W is swept toward the two pulleys P1 and P2.

  In addition, a plurality of cleaning nozzles (pin spot type) are provided on the entire outer periphery of the two PVA brushes B1 and B2 over their entire length in the axial direction. The cleaning nozzle is composed of a cylindrical protrusion. All the cleaning nozzles communicate with the insides of the PVA brushes B1 and B2, and pure water (deionized water, hereinafter referred to as DIW) is supplied (press-fit) into the PVA brushes B1 and B2. Then, the DIW is configured to be ejected (discharged) from the cleaning center of the PVA brushes B1 and B2 from the axial center toward the outer periphery. DIW is supplied by a predetermined pump (not shown) provided on each of the two PVA brushes B1 and B2. The supply amount of DIW is set to, for example, 2500 ml / min per PVA brush. The DIW sprayed from the cleaning nozzle removes particles adhering to the surface of the wafer W or the copper wiring.

  When the cleaning of the wafer W is started, the first PVA brush B1 and the second PVA brush B2 are in contact with the wafer W and are swept out toward the two pulleys P1 and P2, respectively. While rotating, the two pulleys P1 and P2 supporting the wafer W rotate. Therefore, the contact surface of the wafer W with which the first PVA brush B1 and the second PVA brush B2 come into contact is changed as needed by the rotation of the wafer W. Therefore, the first PVA brush B1 and the second PVA brush B2 uniformly clean the entire surface of the wafer W.

  Furthermore, a first spray bar S1 (a left spray bar) having a plurality of nozzles N and a second spray bar are provided at the upper left and right inside the first cleaning unit C1, in other words, above the main surface with respect to the wafer W. The spray bar S2 (right spray bar) is arranged so as to sandwich the wafer W. A cleaning chemical solution (organic acid cleaning chemical solution in the first cleaning unit C1 and organic alkaline cleaning chemical solution in the second cleaning unit C2) prepared for wafer cleaning is applied to the first spray bar S1 and the second spray bar S2. The cleaning chemical solution is supplied by a predetermined cleaning chemical solution pump (not shown), and the supplied cleaning chemical solution is jetted from each nozzle N to both surfaces of the wafer W. For example, five nozzles N are provided for one spray bar. However, the number of nozzles N may be appropriately changed as long as the cleaning chemical liquid can be sprayed (discharged) uniformly on the surface of the wafer W. The Further, the discharge shape of the cleaning chemical liquid discharged from the plurality of nozzles N provided in one spray bar is a fan with respect to the center line of the wafer W so that the cleaning chemical liquid is uniformly discharged onto the surface of the wafer W. Mold shape is adopted. As the discharge shape, a full cone shape, a straight shape, or the like may be adopted as another shape.

  Each of the first spray bar S1 and the second spray bar S2 has a switching valve (not shown) at the supply source to which the cleaning chemical liquid is supplied, and the cleaning chemical liquid and DIW are switched and supplied. It is the composition which becomes. In the first embodiment, by having the switching valve, even with a pair of spray bars (first spray bar S1, second spray bar S2), the cleaning chemical liquid and DIW are switched to perform injection (discharge). Although possible configurations are possible, other configurations may be used. For example, a new pair of spray bars having an axis parallel to the axis of the pair of spray bars may be provided, and the cleaning chemical solution and DIW may be ejected (discharged) from independent spray bars. I do not care.

  In the first embodiment, the orientation of the wafer housed in the first cleaning unit is configured as a substantially vertical direction, but may be configured in a substantially horizontal direction. In that case, a pair of PVA brushes are arranged so as to sandwich a substantially horizontal wafer from above and below. The contact surface between the wafer and the PVA brush is linear regardless of whether the wafer is substantially vertical or substantially horizontal. In order for the PVA brush to uniformly clean the entire wafer surface, the rotation axis of the PVA brush, the surface of the wafer, Are configured to be parallel to each other.

  The control unit 100 described above is connected to the first cleaning unit C1. The control unit 100 rotates the two pulleys P1 and P2, the rotation of the two PVA brushes B1 and B2, the driving of a predetermined pump corresponding to the two PVA brushes B1 and B2, and the first spray bar. Control of the driving of a predetermined cleaning chemical pump corresponding to S1 and the second spray bar S2, switching of the switching valve, and the like is controlled.

  As described above, the main configuration of the first cleaning unit C1 has been described with reference to FIG. 2, but the main configuration of the second cleaning unit C2 is the same as the main configuration of the first cleaning unit C1. However, the main configuration of the second cleaning unit C2 does not include the first PVA brush B1 and the second PVA brush B2.

  Next, in the cleaning process after Cu-CMP, a mechanism in which particles adhering to the PVA brush reattaches to the lower layer wiring of the wafer and causes poisoning failure due to the particles will be described.

  FIG. 3 is a distribution diagram of defects on the wafer surface after performing brush scrub cleaning with a PVA brush and performing photolithography. 3 indicates the direction in which the wafer is taken out from the first cleaning unit C1 after brush scrub cleaning.

  As shown in FIG. 3, it is confirmed that the distribution of defects on the wafer surface forms a single band (hereinafter referred to as a band-shaped pattern formation defect) in a direction perpendicular to the arrow direction in FIG. Is done. Further, it is confirmed that the band-shaped pattern formation defect passes through the center of the wafer.

  Here, the first PVA brush B1 or the second PVA brush B2 installed in the first cleaning unit C1 is the center of the wafer when the wafer after brush scrub cleaning is taken out from the first cleaning unit C1. And is arranged in a direction perpendicular to the arrow direction in FIG. Therefore, when the PVA brush (the first PVA brush B1 or the second PVA brush B2) is detached from the wafer surface, the particles attached to the PVA brush are reattached to the wafer surface. It is estimated to be.

  Next, FIG. 4 shows an image diagram of a typical pattern after performing photolithography. FIG. 4A shows an image corresponding to a wafer having no strip-like pattern formation defect shown in FIG. FIG. 4B shows an image corresponding to the wafer having the band-like pattern formation defect shown in FIG. The arrow direction in FIG. 4 corresponds to the same direction as the arrow in FIG. 3 and indicates the direction in which the wafer from which the PVA brush is detached after brush scrub cleaning is taken out from the first cleaning unit C1.

  As shown in FIG. 4A, when photolithography is performed on a wafer having no strip-like pattern formation defect, a predetermined line pattern L is formed in the direction perpendicular to the arrow direction without causing defects. Is confirmed. On the other hand, as shown in FIG. 4B, when photolithography is performed on a wafer having a band-like pattern formation defect, it should be formed on a via V (a via hole in which an antireflection film is embedded) on the wafer surface. It is confirmed that the line pattern L is not formed and a line formation defect (a region indicated by a dotted line in FIG. 4B) occurs. The occurrence of line formation failure is also referred to as Cu wiring open failure.

  This is because when a band-like pattern formation failure occurs on a wafer, a poisoning failure, that is, a resolution failure of a chemically amplified resist occurs, and the intended line pattern L cannot be formed (the line formation failure occurs). ). As a result, the yield of the wafer is deteriorated.

  Next, the mechanism by which particles adhering to the PVA brush are reattached on the wafer surface will be described.

FIG. 5 is a diagram showing a relationship between a zeta potential corresponding to a member existing in brush scrub cleaning after Cu-CMP and a pH in a cleaning chemical solution in which the member exists. Examples of the member include Cu corresponding to a Cu wiring or a polished Cu film, SiO ₂ corresponding to a polishing abrasive grain of a wafer, and PVA corresponding to an organic component derived from a PVA brush. The zeta potential is measured according to JIS Z 8901, for example. Further, the zeta potential corresponding to the member marked with * indicates a value measured using an organic acid cleaning chemical as the cleaning chemical. The members marked with * correspond to Cu * and SiO ₂ *. The reason for the measurement using the organic acid cleaning chemical solution is that the zeta potential of Cu * and SiO ₂ * to be measured is the zeta of Cu * and SiO ₂ * under the conditions in brush scrub cleaning after Cu-CMP. This is to bring it close to the potential. Further, the change in zeta potential corresponding to the member marked with * is indicated by a broken line in FIG. Further, the zeta potential corresponding to a member not marked with * indicates a value measured using an inorganic cleaning chemical (inorganic acid cleaning chemical or inorganic alkaline cleaning chemical) as the cleaning chemical. Members not marked with * correspond to Cu, SiO ₂ and PVA. A change in zeta potential corresponding to a member not marked with * is indicated by a solid line in FIG.

As shown in FIG. 5, for example, in the acidic region (pH 3 to 4), the zeta potential of Cu * and SiO ₂ * measured with an organic acid cleaning chemical solution and the PVA measured with an inorganic acid cleaning chemical solution It is confirmed that all the zeta potentials are negative potentials. Therefore, when brush scrub cleaning is performed using an organic acid cleaning chemical solution (pH 3 to 4), the organic component derived from the PVA brush and the SiO ₂ or Cu as abrasive grains are immersed in the organic acid cleaning chemical solution due to electrostatic repulsion. It is understood that it does not adhere on the Cu wiring of the formed wafer.

In addition, in the neutral pH range (pH 6-8), although the zeta potential of Cu measured with an inorganic acid cleaning solution or an inorganic alkaline cleaning solution is a positive potential, it is measured with an inorganic acid cleaning solution or an inorganic alkaline cleaning solution. It is confirmed that the zeta potential of SiO ₂ and PVA is a negative potential. Therefore, for example, when brush scrub cleaning is performed using DIW corresponding to a neutral region, the organic components and abrasive grains easily adhere to the Cu wiring of the wafer immersed in DIW due to electrostatic attraction. It is understood.

  In the cleaning process in the conventional first cleaning unit C1, the vicinity of the contact surface between the PVA brush and the wafer is kept almost neutral (pH 6 to 8) by DIW sprayed (discharged) from the inside of the PVA brush. Was composed. Therefore, when the PVA brush is detached from the wafer after the brush scrub cleaning, particles (for example, the organic components and polishing abrasive grains described above) adhering to the PVA brush due to the electrostatic attraction described above are formed on the Cu wiring. It is estimated that it will reattach easily. As a result, as shown in FIG. 3, the reattached particles form a band-like pattern formation defect on the wafer.

Furthermore, in the alkaline region (pH 9 to 10), it is confirmed that all the zeta potentials of Cu, SiO ₂ and PVA measured with the inorganic acid cleaning chemical or the inorganic alkaline cleaning chemical are negative. For this reason, when the wafer is cleaned using an alkaline cleaning chemical (for example, an organic alkaline cleaning chemical having a pH of 9 to 10), the organic components and abrasive grains do not adhere to the Cu wiring of the wafer due to electrostatic repulsion. Is understood.

  Next, a mechanism in which, for example, particles remaining on the Cu wiring cause poisoning failure after Cu-CMP will be described in detail.

  FIG. 6 is a diagram showing a mechanism in which particles on Cu wiring cause poisoning defects and an example of a manufacturing method of a Cu wiring multilayer wiring process (dual damascene process).

  FIG. 6A shows the first low dielectric constant film 601 in which the Cu wiring 603 is formed by the damascene method (corresponding to FIG. 13B). The first low dielectric constant film 601 corresponds to, for example, a carbon-containing silicon oxide film (SiOC film), and the first low dielectric constant film 601 is formed on the wafer. In the Cu wiring 603, a trench having a predetermined depth (for example, 300 nm) is formed in the low dielectric constant film 601 having a predetermined thickness (for example, 600 nm), and a barrier metal film made of TaN is formed in the trench. A film 602 is formed, and a Cu film is embedded on the barrier metal film 602. The Cu wiring 603 is formed through a Cu-CMP process. FIG. 6A shows a state in which particles 604 are reattached on the Cu wiring 603 by brush scrub cleaning after Cu-CMP. Show.

  FIG. 6B shows a state in which the particle 604 is reattached on the Cu wiring 603 and is being reduced by ammonia plasma (corresponding to FIG. 13C). By the reduction treatment, the Cu oxide layer formed on the surface of the Cu wiring 603 is reduced, and minute foreign matters existing on the Cu wiring 603 or the first low dielectric constant film 601 are removed. When the reduction treatment is executed, the methyl group (—CH 3) and the ammonia radical in the first low dielectric constant film 601 are combined to generate an amine 605 (methylamine, ie, a base). Further, when the particles 604 reattached on the Cu wiring 603 are organic foreign matters, the organic foreign matters are combined with ammonia radicals (NH 3 radicals) in the ammonia plasma, so that the basicity different from the amine described above is obtained. The amine which it has may be produced | generated. Therefore, when the reduction process is executed, the amine 605 remains on the executed Cu wiring 603 or the first low dielectric constant film 601.

  Next, FIG. 6C shows a state in which a diffusion prevention film 606 having a predetermined thickness (for example, 50 nm) is formed on the first low dielectric constant film 601 after the reduction treatment (FIG. 6). 13 (c)). The diffusion prevention film 606 corresponds to, for example, a silicon carbonitride film (SiCN film). When the diffusion prevention film 606 is formed on the Cu wiring 603 and the first low dielectric constant film 601 in a state where the particles 604 are attached on the Cu wiring 603, the diffusion prevention film 606a lifted only on the part of the particles 604 is formed. It is formed. It is understood that a hole 606b that connects the first low dielectric constant film 601 and the upper surface of the Cu wiring 603 is formed between the diffusion prevention film 606a and the diffusion prevention film 606 that are lifted only by the particle 604. That is, when the particles 604 adhere on the Cu wiring 603, the diffusion preventing function of the diffusion preventing film 606 is lost. Therefore, the amine 605 remaining on the Cu wiring 603 or the first low dielectric constant film 601 can pass through the hole 606b and be diffused above the diffusion preventing film 606.

  Next, a second low dielectric constant film 607 as an interlayer insulating film is formed on the diffusion prevention film 606 having the hole 606b, and a via hole 608 is opened on the Cu wiring 603 by dry etching (FIG. 13). (Corresponds to (e)). An antireflection film 609 is embedded in the opened via hole 608, and a second chemically amplified resist 610 is applied thereon (corresponding to FIG. 13F).

  FIG. 6D shows a state where the second chemically amplified resist 610 is applied and a photolithography process is performed.

  As shown in FIG. 6D, since a hole 606b is formed between the diffusion prevention film 606a and the diffusion prevention film 606 which are lifted only by the part of the particle 604, it remains on the first low dielectric constant film 601. The amine 605 will pass through the hole 606b. Further, the amine 605 passes through the via hole 608 formed on the Cu wiring 603 and is absorbed (penetrated) into the applied second chemically amplified resist 610. The absorbed amine 605 is neutralized with the acid generated in the second chemically amplified resist 610 by exposure to weaken the chemical amplification action when forming the resist pattern. For this reason, a poor resolution of the chemically amplified resist, that is, a poor poisoning occurs, and as a result, the intended line pattern L cannot be formed on the wafer in photolithography as described with reference to FIG. It becomes.

  Next, using the Cu-CMP apparatus 10 having two cleaning units, the wafer cleaning that appropriately removes particles after brush scrub cleaning that causes poisoning failure and prevents reattachment of particles to the wafer is performed. A method will be described.

  FIG. 7 is a flowchart for illustrating a two-step cleaning procedure for a wafer after Cu-CMP according to the first embodiment.

  First, a plurality of wafers in which a Cu film is embedded in the trench on the first low dielectric constant film are stored in the FOUP, and the FOUP is carried into a load port LP1 in the Cu-CMP apparatus 10, for example. When the FOUP is loaded, as shown in FIG. 1, the control unit 100 of the Cu-CMP apparatus 10 receives a predetermined control signal and drives the dry robot R1 and the wet robot R2 to load the predetermined wafer into the FOUP. To the load / unload unit U1 of the polishing unit 2.

  The predetermined wafer transferred to the load / unload unit U1 is further transferred from the first polishing platen P1 to the third polishing platen P3 via the heads H1 to H4 connected to the wafer rotation mechanism part X1. Each time a predetermined wafer is transferred from the first polishing platen P1 to the third polishing platen P3, the wafer is subjected to CMP. When the polishing of the excess Cu film and the barrier metal film existing on the wafer is completed by Cu-CMP, it is transferred again to the load / unload unit U1 (FIG. 7: S701).

  The Cu-CMP wafer transferred to the load / unload unit U1 is transferred from the polishing unit 2 to the cleaning unit receiving unit CIN of the cleaning unit 3 by the wet robot R2. The wafer after Cu-CMP transferred to the cleaning unit receiving unit CIN is further carried into the first cleaning unit C1 by the robot R3. The loaded wafer is supported by the front pulley P1 and the rear pulley P2 in the first cleaning unit C1, and stored in a state substantially perpendicular to the machine floor (FIG. 7: S702).

  When the wafer after Cu-CMP is stored in the first cleaning unit C1, the control unit 100 performs brush scrub cleaning using an organic acid cleaning chemical (FIG. 7: S703).

  Specifically, the control unit 100 brings the first PVA brush B1 and the second PVA brush B2 provided in the first cleaning unit C1 into contact with the surface of the wafer, respectively, and the first PVA brush B1 The rotation speed of the second PVA brush B2 is set to 300 rpm. Further, the control unit 100 rotates the front pulley P1 and the rear pulley P2 provided in the first cleaning unit C1 at 50 rpm, and rotates the wafer supported by the two pulleys P1 and P2. Then, the wafer is rotated at a predetermined rotational speed. Further, the control unit 100 drives a predetermined cleaning chemical pump, and the first spray bar S1 and the second spray bar S2 provided in the first cleaning unit C1 each have an organic acid cleaning having a pH of 3 to 4. Supply chemicals. The flow rate of the supplied organic acid cleaning chemical is set to 2000 ml / min for each spray bar. In addition, even if DIW is not supplied to the two PVA brushes B1 and B2, or even if DIW is supplied, the pH of the organic acid cleaning chemical that immerses the wafer is supplied at a flow rate that falls within the range of 3 to 4. .

When the above-described conditions are satisfied, as shown in the acidic region of FIG. 5, the state in which the organic acid cleaning chemical solution in the range of pH 3 to 4 is immersed in the wafer surface, that is, the organic component derived from the PVA brush or the SiO 2 which is the abrasive grain. Brush scrub cleaning is performed in a state where particles composed of ₂ or Cu hardly adhere to the Cu wiring. In this state, the PVA brush corresponds to a state in which particles are most easily removed from the Cu wiring. Therefore, when brush scrub cleaning is executed in this state, it is possible to suppress the occurrence of poor poisoning due to particles as shown in FIG. Note that the brush scrub cleaning under the above conditions is continuously executed for 50 seconds, for example.

  After 50 seconds, the control unit 100 removes the two PVA brushes B1 and B2 provided in the first cleaning unit C1 from the wafer surface. When the desorption is performed, the pH of the organic acid cleaning chemical that immerses the wafer and the two PVA brushes B1 and B2 is in the range of 3 to 4, and is in the neutral range (pH 6 to 8). Never fit in.

  After the detachment, the control unit 100 switches the switching valves provided in the first spray bar S1 and the second spray bar S2, for example, so that the first spray bar S1 and the second spray bar are switched. The organic acid cleaning chemical supplied to S2 is changed to DIW, DIW is sprayed onto the wafer at a predetermined flow rate, and DIW cleaning is executed on the wafer. The DIW cleaning is also referred to as DIW rinsing, and the DIW rinsing is continuously executed for 15 seconds (FIG. 7: S704).

  When the DIW rinsing of the wafer is completed, the control unit 100 drives the robot R3 to transport the wafer after DIW rinsing from the first cleaning unit C1 to the second cleaning unit C2. When the wafer after DIW rinsing is supported by the front pulley P1 and the rear pulley P2 in the second cleaning unit C2, and stored in a state substantially perpendicular to the machine floor, the controller 100 performs organic alkali cleaning. The wafer is cleaned using the chemical solution (FIG. 7: S705).

  Specifically, the control unit 100 rotates the front pulley P1 and the rear pulley P2 provided in the second cleaning unit C2 at 50 rpm so that the wafer is supported by the two pulleys P1 and P2. The rotation is transmitted, and the wafer is rotated at a predetermined number of rotations. Further, an organic alkaline cleaning chemical solution having a pH of 9 to 10 is supplied to each of the first spray bar S1 and the second spray bar S2 provided in the second cleaning unit C2. The flow rate of the supplied organic alkali cleaning chemical is set to 1500 ml / min for each spray bar. Since the second cleaning unit C2 is not provided with two PVA brushes B1 and B2, brush scrub cleaning is not performed in the cleaning.

  Assuming that the conditions described above are satisfied, as shown in the alkali region of FIG. 5, an organic alkali cleaning chemical solution having a pH of 9 to 10 immerses the wafer surface, that is, particles are difficult to adhere to the Cu wiring. Cleaning will be performed. This state corresponds to a state in which particles are most easily removed from the Cu wiring. Therefore, when the wafer is cleaned in this state, the occurrence of the poisoning failure due to the above-described particles is surely suppressed. Furthermore, since the organic alkali cleaning chemical solution etches the surface of the Cu wiring, even if particles remain on the Cu wiring, it can be appropriately removed. Note that the cleaning under the conditions is continuously performed for 15 seconds, for example.

  In the initial stage when the organic alkali cleaning chemical solution of pH 9 to 10 is sprayed onto the wafer, the organic alkali cleaning chemical solution is still diluted by DIW after DIW rinsing remaining on the wafer, but the organic alkali cleaning is continued. Since the chemical solution is sprayed onto the wafer, the diluted cleaning chemical solution flows downward, and as a result, the organic alkaline cleaning chemical solution having a pH of 9 to 10 immerses the wafer surface to clean the wafer.

  After 15 seconds, the control unit 100 switches the switching valves provided in the first spray bar S1 and the second spray bar S2 of the second cleaning unit C2 to switch between the first spray bar S1 and the first spray bar S1. The organic alkali cleaning chemical supplied to the second spray bar S2 is changed to DIW, and DIW rinsing of the wafer is executed (FIG. 7: S706). The DIW rinse is executed continuously for 15 seconds, for example.

  When the DIW rinsing is completed, the controller 100 drives the robot R3, conveys the wafer after completion of the DIW rinsing from the second cleaning unit C2 to the drying unit D1, and executes a drying process on the wafer after the DIW rinsing (FIG. 7: S707).

  As a drying method, a spin drying method in which the wafer is rotated at a high speed and dried by centrifugal force may be adopted. A vapor phase IPA (isopropyl alcohol) is sprayed on the wafer and DIW is utilized by utilizing the Marangoni effect. A Marangoni drying method that removes and dries may be adopted. The Marangoni effect is an effect in which a solution flow is generated by a concentration gradient of different solutions. In the Marangoni drying method, the flow of the solution due to the concentration gradient between IPA and DIW is used to reduce and dry DIW remaining on the wafer surface. When a hydrophobic low dielectric constant film is used as an interlayer insulating film as in the first embodiment, the DIW remaining on the wafer surface is dried, so that impurities contained in the DIW are formed on the wafer surface. A watermark that remains and is a mark formed based on the impurities is likely to occur. In order to prevent the occurrence of the watermark, a Marangoni drying method is preferably employed.

  When the drying is completed, the control unit 100 drives the dry robot R1 to carry out the dried wafer from the drying unit D1, carry the dried wafer into the FOUP disposed in the load port LP1, and perform a series of operations for one wafer. The process is completed (FIG. 7: S708).

  The wafers that have been subjected to the cleaning process after Cu-CMP in the above-described procedure are further processed by the processes shown in FIGS. 6B to 6D, that is, the reduction process, the formation process of the diffusion prevention film, 2 low dielectric constant film forming process, via hole forming process by dry etching, antireflection film embedding process, second chemically amplified resist coating process, and photolithography are sequentially performed.

  When the wafer on which photolithography was performed was observed, the defects (strip-shaped pattern formation defects) shown in FIG. 3 were not confirmed. Although several tens of wafers to be observed were observed, the defect was not confirmed for all the wafers. This result shows that the particles adhering to the two PVA brushes B1 and B2 are prevented from re-adhering on the Cu wiring by performing the wafer cleaning method described above. Therefore, it is shown that the occurrence of the poisoning failure caused by the particles can be prevented by executing the above-described two-stage cleaning after Cu-CMP.

  Thus, in the cleaning process after Cu-CMP, the cleaning process performs at least two stages of cleaning, the first stage performs brush scrub cleaning using an organic acid cleaning chemical, and the second stage includes The cleaning is performed using an organic alkali cleaning chemical.

  As a result, in the first stage, since the cleaning chemical used in the brush scrub cleaning is an organic acid, both the Cu wiring and the particles have a negative potential. Therefore, it is possible to prevent particles from adhering to the Cu wiring, or particles adhering to the PVA brush from re-adhering to the Cu wiring. Furthermore, in the second stage, since cleaning is performed using an organic alkali cleaning chemical solution, both the Cu wiring and the particles have a negative potential, and it is possible to appropriately remove the particles remaining on the Cu wiring. . Further, since the organic alkali cleaning chemical solution etches the surface of the Cu wiring, even if particles remain on the surface of the Cu wiring, the particles can be appropriately removed. As a result, after cleaning, for example, even if reduction processing or photolithography is performed, it is possible to appropriately prevent poisoning defects caused by particles reattached on the Cu wiring and improve the yield of the semiconductor manufacturing apparatus. It becomes possible.

  The first stage of the cleaning process performs brush scrub cleaning using an organic acid cleaning chemical solution having a pH of 3 to 4, and the second stage of the cleaning process includes organic alkali cleaning having a pH of 9 to 10. It can comprise so that it may wash | clean using a chemical | medical solution.

  Thereby, in the first stage, the brush scrub cleaning is performed in a state where both the Cu wiring and the particles surely have a negative potential. Further, even in the second stage, cleaning is performed in a state where both the Cu wiring and the particles have a negative potential. Therefore, it is possible to minimize the possibility of particles remaining on the Cu wiring in the cleaning process after Cu-CMP, thereby minimizing the occurrence of poisoning defects and improving the yield of semiconductor manufacturing equipment. It becomes.

<Second Embodiment>
In the first embodiment, at least two stages of cleaning are performed in the cleaning process after Cu-CMP, the first stage is brush scrub cleaning using an organic acid cleaning chemical, and the second stage is organic. A method of manufacturing a semiconductor device that performs cleaning using an alkaline cleaning chemical solution is provided. This manufacturing method has succeeded in preventing particles from adhering to the wafer or particles adhering to the brush from reattaching to the wafer, thereby preventing the occurrence of poisoning defects.

  However, in the first stage, when a contact abnormality occurs in which the two PVA brushes B1 and B2 and the surface of the wafer are not in uniform contact, excessive particles may remain and adhere to the wafer. . The contact abnormality is caused by, for example, warping or twisting of the PVA brush that occurs due to long-term use. When a PVA brush that has been warped or twisted is pressed against the wafer surface, the pressing amount of the pressed portion (contact surface) becomes uneven at both ends of the PVA brush. The pressing amount is an amount pressed toward the wafer W from a state where the PVA brushes B1 and B2 are in contact with the wafer W to a predetermined amount. When the pressing amount is large, the number of particles adhering to the PVA brushes B1 and B2 from the wafer (particles removed by the PVA brush) increases while the particles adhering to the wafer from the PVA brushes B1 and B2 are increased. The number will also increase. For this reason, in the portion of the wafer where the pressing amount is large, particles remain excessively and adhered. When particles adhere to the wafer excessively, even if the manufacturing method according to the first embodiment is adopted, all the particles may not be removed. Since the above-described poisoning failure occurs due to the particles that are not removed, the pressing amount needs to be uniformly maintained in all the pressed portions between the contact surface of the PVA brush and the contact surface of the wafer.

  Therefore, in the second embodiment, a configuration is adopted in which it is detected that the contact (pressing) state of the PVA brush to the wafer is not uniform. The nonuniformity of the contact state (contact abnormality) is determined by whether or not the number of rotations corresponding to the rotation of the wafer is included in a predetermined range. Further, the wafer cleaning process is stopped when the contact state is non-uniform. Hereinafter, the second embodiment will be described in detail.

  FIG. 8 is a schematic configuration diagram showing a Cu-CMP apparatus according to the second embodiment of the present invention. Similar to the first embodiment, the vertical direction in FIG. 8 will be described as the front-rear direction of the Cu-CMP apparatus 10, and the horizontal direction in FIG. 8 will be described as the left-right direction of the Cu-CMP apparatus 10.

  The Cu-CMP apparatus 10 in the second embodiment is different from the Cu-CMP apparatus 10 shown in the first embodiment in that process parameters measured (detected) in the Cu-CMP apparatus 10 are measured. A monitoring tool 200 (Monitoring Tool: MT) acquired every time is communicably connected to the Cu-CMP apparatus 10. Furthermore, a determination unit 201 that determines whether or not the number of rotations corresponding to the rotation of the wafer is included in a predetermined range based on the process parameters acquired by the monitoring tool 200 is connected to the monitoring tool 200. It is.

  The monitoring tool 200 is connected to each part provided in the Cu-CMP apparatus 10 (for example, a motor for the front pulley P1, a detector for detecting the number of rotations of the wafer rotation pulley D described later, etc.). To get. Further, the determination unit 201 transmits the determination result based on the process parameter transmitted from the monitoring tool 200 to the control unit 100 of the Cu-CMP apparatus 10. The said control part 100 performs control of the Cu-CMP apparatus 10 according to the said determination result.

  Next, a method in which the monitoring tool 200 acquires process parameters from, for example, main components of the first cleaning unit C1 of the cleaning unit 3 will be described with reference to FIG. FIG. 9 is a diagram showing a main configuration of the first cleaning unit C1 and the monitoring tool 200 in the cleaning unit 3 of the Cu-CMP apparatus 10 according to the second embodiment of the present invention. 9 corresponds to the downward direction in FIG. 8, and the right direction of the first cleaning unit C1 in FIG. 9 corresponds to the right direction in FIG. The two pulleys P1 and P2 have the same radius, and the rotation axes P1a and P2a are both orthogonal to the surface of the stored wafer W.

  As shown in FIG. 9, two pulleys (front pulley P1 and rear pulley P2) provided before and after the inside of the first cleaning unit C1 are each provided with a motor (not shown). A monitoring tool 200 is connected to these motors. When the control unit 100 drives the motor, the monitoring tool 200 acquires the current values of those motors (corresponding to the rotation speeds of the front pulley P1 and the rear pulley P2) as process parameters. The acquired current value of the motor is converted into the rotation speed of the pulley by a table stored in a predetermined memory and relating the current value and the rotation speed of the pulley.

  In this embodiment, the center of the lower end of the wafer W (or the vicinity of the center of the lower end) is supported between the two pulleys P1 and P2 that support the wafer W substantially perpendicular to the machine floor, and the two pulleys are supported. A wafer rotation pulley D having the same radius as that of P1 and P2 is newly provided. The wafer rotating pulley D is not connected to a motor that drives the pulley. The rotation axis Da of the wafer rotation pulley D is designed to be parallel to the rotation axes P1a and P2a of the two pulleys P1 and P2. Further, the rotation axis Da includes the rotation of the wafer rotation pulley D. A detector (not shown) for detecting the number is provided. Therefore, when the wafer W is rotated by the rotation of the two pulleys P1 and P2, the rotation of the wafer W is transmitted to the wafer rotation pulley D. Then, the wafer rotation pulley D rotates at a rotation speed corresponding to the rotation of the wafer W. When the detector detects the rotation speed of the wafer rotation pulley D, the rotation speed corresponding to the rotation of the wafer W can be detected. Further, since the radius of the wafer rotation pulley D has the same radius as that of the two pulleys P1 and P2, the rotation of the two pulleys P1 and P2 is appropriately transmitted to the wafer W. The number of rotations of the wafer rotation pulley D is equal to the number of rotations of the two pulleys P1 and P2. A monitoring tool 200 is connected to the detector, and the monitoring tool 200 acquires the rotation speed of the wafer rotation pulley D detected by the detector as a process parameter (here, the actual rotation speed of the wafer). To do.

  The first PVA brush B1 (left PVA brush) and the second PVA brush B2 (right PVA brush) provided on the left and right sides of the first cleaning unit C1 are brushes that detect the number of rotations of the brush. A rotation number detector (not shown), a brush motor (not shown) for rotating the brush, a flow rate of DIW supplied to the inside of the PVA brushes B1 and B2 and a brush flow rate for detecting the pressure (discharge pressure) A pressure detector (not shown) is provided. A monitoring tool 200 is connected to the brush rotation number detector, the brush motor, and the brush flow rate pressure detector. When the control unit 100 drives the brush motor and supplies DIW into the PVA brushes B1 and B2 using a predetermined pump, the monitoring tool 200 applies the first PVA brush B1 and the second PVA brush B2. The corresponding process parameters (PVA brush rotation speed, motor current value, DIW flow rate, pressure) are acquired.

  Further, the cleaning chemical liquid (or DIW) is supplied to the first spray bar S1 and the second spray bar S2 disposed on the upper left and right sides inside the first cleaning unit C1, respectively. In addition, each of the spray bars S1 and S2 is provided with a spray bar flow rate pressure detector (not shown) for detecting the flow rate of the supplied cleaning chemical and its pressure (discharge pressure). A monitoring tool is connected to the pressure detector. When the control unit 100 supplies the cleaning chemical liquid (or DIW) to the first spray bar S1 and the second spray bar S2 using a predetermined cleaning chemical liquid pump, the monitoring tool 200 is connected to the first spray bar S1 and the first spray bar S1. Process parameters (flow rate and pressure of cleaning chemical (or DIW)) corresponding to each of the two spray bars S2.

  With the configuration described above, the monitoring tool 200 connected to a plurality of detectors and the like can acquire process parameters detected from the detectors and the like.

  Next, the number of rotations of the front pulley P1 and the rear pulley P2, which can be acquired by the monitoring tool 200, the actual number of rotations of the wafer, and the contact state between the two PVA brushes B1 and B2 and the surface of the wafer W , Contact state) will be described with reference to FIGS.

  FIGS. 10 and 11 are diagrams showing the contact state and the change over time in the actual rotation speed of the wafer when the brush scrub cleaning is performed in the contact state. 10 and 11 correspond to the front-rear direction of the first cleaning unit C1 including the wafer W and the two PVA brushes B1 and B2. Moreover, the arrow direction of FIG. 10, FIG. 11 has shown the front direction of the 1st washing | cleaning unit C1.

  In FIG. 10A, the axes of the two PVA brushes B1 and B2 are held parallel to the surface of the wafer W, respectively, and the two PVA brushes B1 and B2 and the wafer W are in contact with each other. Show. When the PVA brushes B1 and B2 are in contact with the wafer W, the PVA brushes B1 and B2 are pressed toward the wafer W from a state where they are in contact with the wafer W, and the pressed amount ( The PVA brushes B1 and B2 are deformed by the pressing amount). FIG. 10A shows a state where the PVA brushes B1 and B2 are pressed against the wafer W by a predetermined pressing amount when the wafer W does not exist. Note that the solid line wafer W shown in FIG. 10A indicates a position where the wafer W exists.

  As shown in FIG. 10A, the first PVA brush contacts the front surface of the wafer W, the second PVA brush contacts the back surface of the wafer W, and the contact surfaces of the two PVA brushes B1 and B2 are all on the wafer. It is pressed against the entire W contact surface with a pressing amount of 1.0 mm. This state indicates that there is no abnormality in the contact state, or the contact state is uniform.

  FIG. 10B shows the actual rotation of the wafer when the brush scrub cleaning is performed in the contact state of FIG. 10A when the rotation speed of the front pulley P1 and the rear pulley P2 is 50 rpm. The change with time is shown. The change with time of the actual rotational speed of the wafer corresponds to a graph in which the actual rotational speed of the wafer acquired by the monitoring tool 200 is plotted against the cleaning time which is the time from the start of cleaning to the end of cleaning. Note that a predetermined time interval T shown in FIG. 10B indicates a time interval at which brush scrub cleaning is performed (approximately 50 seconds in FIG. 10B).

  FIG. 11A shows a state in which the axes of the two PVA brushes B1 and B2 are inclined with respect to the wafer W, and the two PVA brushes B1 and B2 are in contact with the wafer W. Yes. The inclined state corresponds to, for example, a state in which the axes of the PVA brushes B1 and B2 are inclined at a predetermined angle with respect to the center of the wafer W, and the axes of the two PVA brushes B1 and B2 are respectively on the surface of the wafer W. Corresponds to the state of not parallel.

  As shown in FIG. 11A, the first PVA brush B1 comes into contact with the surface of the wafer W, and one end of the contact surface of the first PVA brush B1, in other words, the contact surface of the first PVA brush B1. The front end is pressed against the contact surface of the wafer W with a pressing amount of 1.5 mm. Also, the other end of the contact surface of the first PVA brush B1, in other words, the rear end of the contact surface of the first PVA brush B1 is pressed against the contact surface of the wafer W with a pressing amount of 0.5 mm. Furthermore, the second PVA brush B2 contacts the back surface of the wafer W, and one end of the contact surface of the second PVA brush B2, in other words, one front end of the contact surface of the second PVA brush B2 is the contact surface of the wafer W. Is pressed against the one end with a pressing amount of 1.5 mm. Further, the other end of the contact surface of the second PVA brush B2 and the rear end of the contact surface of the second PVA brush B2 are pressed against the other end of the contact surface of the wafer W with a pressing amount of 0.5 mm. This state indicates that the contact state is abnormal (contact abnormality) or the contact state is not uniform.

  FIG. 11B shows the actual rotation of the wafer when the brush scrub cleaning is performed in the contact state of FIG. 11A when the rotational speeds of the front pulley P1 and the rear pulley P2 are 50 rpm. The change with time is shown.

  As shown in FIGS. 10A and 10B, when the contact state between the two PVA brushes B1 and B2 and the wafer W is uniform, the actual number of rotations of the wafer acquired by the monitoring tool 200 is It is understood that 50 rpm, that is, the rotation speed of the front pulley P1 and the rear pulley P2 is equivalent.

  On the other hand, as shown in FIGS. 11A and 11B, when the contact state between the two PVA brushes B1 and B2 and the wafer W is not uniform, the actual rotational speed of the wafer is smaller than 50 rpm. It is understood that it is a value. This is because the contact state is uneven, and even if the rotation of the two pulleys P1 and P2 is properly transmitted to the wafer W, the wafer W is excessively pressed from the two PVA brushes B1 and B2. It is because it will rotate with. That is, since the smooth rotation of the wafer W is hindered, a rotational speed smaller than the rotational speeds of the two pulleys P1 and P2 is detected as the actual rotational speed of the wafer corresponding to the rotation of the wafer W. On the other hand, a portion where the wafer W is hardly pressed from the two PVA brushes B1 and B2 may also occur. In this case, since the rotation of the wafer W is further accelerated, a rotation speed larger than the rotation speeds of the two pulleys P1 and P2 is detected as the actual rotation speed of the wafer corresponding to the rotation of the wafer W.

  By utilizing the phenomenon described above, in the second embodiment, a contact abnormality is detected, and reattachment of particles to the wafer caused by the contact abnormality is prevented.

  FIG. 12 is a flowchart for illustrating a procedure of brush scrub cleaning for a wafer after Cu-CMP according to the second embodiment.

  First, a FOUP containing a plurality of wafers in which a Cu film is embedded in a trench on the first low dielectric constant film is carried into, for example, a load port LP1 in the Cu-CMP apparatus 10. When the FOUP is loaded, the control unit 100 of the Cu-CMP apparatus 10 drives the dry robot R1 and the wet robot R2 to load a predetermined wafer from the FOUP to the polishing unit 2 as shown in FIG. Transport to unload unit U1.

  The predetermined wafer transferred to the load / unload unit U1 is transferred from the first polishing platen P1 to the third polishing platen P3, Cu-CMP is performed, and the excess Cu film and barrier metal film existing on the wafer are Is removed (FIG. 12: S1201).

  The wafer after Cu-CMP is transferred to the cleaning unit receiving unit CIN of the cleaning unit 3 by the wet robot R2, and further transferred into the first cleaning unit C1 by the robot R3. The loaded wafer is supported by the front pulley P1 and the rear pulley P2 in the first cleaning unit C1, and stored in a state substantially perpendicular to the machine floor (FIG. 12: S1202).

  When the wafer after Cu-CMP is stored in the first cleaning unit C1, the control unit 100 performs brush scrub cleaning using an organic acid cleaning chemical (FIG. 12: S1203).

  Specifically, the control unit 100 brings the first PVA brush B1 and the second PVA brush B2 provided in the first cleaning unit C1 into contact with the surface of the wafer with a predetermined pressing amount, respectively. The PVA brush B1 and the second PVA brush B2 are rotated at 300 rpm. Further, the control unit 100 rotates the front pulley P1 and the rear pulley P2 provided in the first cleaning unit C1 at 50 rpm, and transmits the rotation to the wafer supported by the two pulleys P1 and P2. Then, the wafer is rotated at a predetermined rotational speed. Furthermore, the control unit 100 supplies an organic acid cleaning chemical solution having a pH of 3 to 4 to the first spray bar S1 and the second spray bar S2 provided in the first cleaning unit C1. The flow rate of the supplied organic acid cleaning chemical is set to 2000 ml / min for each spray bar.

  Here, when the rotation of the two pulleys P1 and P2 and the rotation of the wafer W are started, the monitoring tool 200 is detected by a detector provided in the wafer rotation pulley D every predetermined period (for example, 2 seconds). The actual number of rotations of the wafer is acquired from (FIG. 12: S1204). Further, the monitoring tool 200 acquires the respective rotation speeds (50 rpm) from the current values of the motors of the two pulleys P1 and P2, and monitors whether the rotation speed transmitted to the wafer W is appropriate.

  When the monitoring tool 200 acquires the actual rotation number of the wafer, the monitoring tool 200 transmits the actual rotation number of the wafer to the determination unit 201. The determination unit 201 that has received the actual number of rotations of the wafer determines whether or not the actual number of rotations of the wafer is within a predetermined range (FIG. 12: S1205). The predetermined range is set in advance by a user or a semiconductor manufacturing apparatus connected to the Cu-CMP apparatus 10, and is appropriately changed according to the number of rotations of the two pulleys P1 and P2. For example, if the rotation speeds of the two pulleys P1 and P2 are 50 rpm, the upper limit value of the predetermined range is set to 52 rpm and the lower limit value is set to 48 rpm.

  As a result of the determination, when the actual number of rotations of the wafer is included in the predetermined range, the determination unit 201 confirms that the contact state is uniform (FIG. 12: S1205 YES). Furthermore, the determination unit 201 communicates with the control unit 100 to determine whether or not the time for performing brush scrub cleaning has elapsed after the determination (FIG. 12: S1206). The time corresponds to a predetermined time interval T shown in FIGS. 10B and 11B, and is hereinafter referred to as a brush scrub cleaning time. The brush scrub cleaning time is set to 50 seconds, for example.

  When the brush scrub cleaning time has not elapsed, the determination unit 201 communicates with the monitoring tool 200, and the monitoring tool 200 starts counting the predetermined period again and repeats the same determination as described above (FIG. 12: S1206 NO → S1204).

  When the contact state is uniform, the control unit 100 continues to perform brush scrub cleaning using the organic acid cleaning chemical until the brush scrub cleaning time elapses.

  When the brush scrub cleaning time has elapsed, the control unit 100 completes the brush scrub cleaning, and the two PVA brushes B1 and B2 provided in the first cleaning unit C1 are detached from the wafer surface, respectively (FIG. 12: S1206 YES → S1207). Further, the control unit 100 switches the switching valves provided in the first spray bar S1 and the second spray bar S2 of the first cleaning unit C1, so that the first spray bar S1 and the second spray bar are switched. The organic alkaline cleaning chemical supplied to the bar S2 is changed to DIW, and DIW rinsing of the wafer is executed (FIG. 12: S1208). The DIW rinse is executed continuously for 15 seconds, for example.

  When the DIW rinsing is completed, the control unit 100 drives the robot R3 to convey the wafer after DIW rinsing from the first cleaning unit C1 to the second cleaning unit C2, and cleans the wafer in the second cleaning unit C2. Will be started.

  On the other hand, as a result of determining whether or not the actual rotation speed of the wafer is included in the predetermined range, if the actual rotation speed of the wafer is outside the predetermined range, the determination unit 201 determines that the contact state is uneven. Then, a signal (signal A) for stopping the brush scrubbing cleaning of the wafer W is transmitted to the controller 100 (FIG. 12: S1205 NO). Note that the case where the actual rotation speed of the wafer is outside the predetermined range corresponds to the case where the actual rotation speed of the wafer exceeds the upper limit value or the case where the actual rotation speed of the wafer is less than the lower limit value.

  The control unit 100 that has received the signal A stops the brush scrub cleaning of the wafer W (FIG. 12: S1209). In this stop, the controller 100 detaches the two PVA brushes B1 and B2 from the wafer W, stops their rotation and the rotation of the two pulleys P1 and P2, and stops the organic acid to the two spray bars S1 and S2. This corresponds to stopping the supply of cleaning chemicals.

  Further, the control unit 100 indicates that, for example, a brush scrub cleaning defect has occurred in a personal computer connected to the Cu-CMP apparatus 10 (for example, a manufacturing execution system (MES) corresponds). Display an error message.

  The determination unit 201 further transmits a control signal to the control unit 100 (signal B) for stopping the execution of the brush scrub cleaning of the subsequent wafer (the wafer scheduled for the next brush scrub cleaning). The unit 100 may be configured to transmit a signal (signal C) indicating that the subsequent FOUP (subsequent lot) is not carried into the Cu-CMP apparatus 10. The control unit 100 that has received the signal B stops the transfer of the subsequent wafer, and the control unit 100 that has received the signal C communicates with the manufacturing execution system described above, and stops the subsequent carry-in of the FOUP.

  With the above configuration, it is possible to prevent the reattachment of particles to the wafer, which frequently occurs when the contact state between the two PVA brushes B1 and B2 and the wafer W is not uniform, and to reduce the yield. Can be prevented.

  Further, for example, after the determination unit 201 confirms that the contact state is non-uniform (after the brush scrub cleaning is stopped due to non-uniform contact state), the user can replace the PVA brush with a new one or the PVA brush. When the attachment state is adjusted and the contact state becomes uniform, the first cleaning unit C1 is restored again, and the brush scrubbing cleaning of the wafer W can be performed.

  Thus, the first stage of the cleaning step includes a step of rotating the wafer on which brush scrub cleaning is performed, and a rotation corresponding to the rotation of the wafer every predetermined period when the rotation of the wafer starts. A step of detecting the number, a step of determining whether or not the detected number of rotations is included in a predetermined range, and the wafer having a detected number of rotations not included in the predetermined range as a result of the determination, the wafer And a step of stopping the brush scrub cleaning.

  Thereby, in the first stage, it is determined whether or not the brush is uniformly in contact with the substrate, and if the brush is not uniformly in contact with the wafer, the brush scrub cleaning of the wafer is stopped. . Therefore, it becomes possible to reliably prevent the reattachment of particles to the lower layer wiring, which frequently occurs when the brush is not uniformly in contact with the wafer. Further, when the brush is not in uniform contact with the wafer, it is possible to stop the brush scrub cleaning on the wafer. As a result, it is possible to appropriately prevent the poisoning failure caused by the particles reattached on the Cu wiring and improve the yield of the semiconductor manufacturing apparatus.

  As described above, a semiconductor device manufacturing method and semiconductor manufacturing capable of suppressing the occurrence of poor poisoning and improving the yield by preventing the reattachment of particles to the wafer in brush scrub cleaning after Cu-CMP. It is effective as a device.

It is a schematic block diagram which shows the Cu-CMP apparatus in 1st embodiment. It is a figure which shows the main structures of the 1st washing | cleaning unit C1 among the washing | cleaning parts of the Cu-CMP apparatus in 1st embodiment. It is a distribution map of the defect on the wafer surface after performing photolithography. It is an image figure of the typical pattern after performing photolithography to the wafer which has a strip | belt-shaped pattern formation defect. It is a figure which shows the relationship between the zeta potential corresponding to the member which exists in the brush scrub cleaning after Cu-CMP, and pH in the cleaning chemical | medical solution in which the member exists. It is the figure which linked and showed the mechanism in which the particle on Cu wiring causes poisoning failure, and an example of the manufacturing method of Cu wiring. It is a flowchart for showing the procedure of a two-step cleaning with respect to the wafer after Cu-CMP in 1st embodiment. It is a schematic block diagram which shows the Cu-CMP apparatus in 2nd embodiment. It is a figure which shows the main structure and monitoring tool of 1st washing | cleaning unit C1 among the washing | cleaning parts of the Cu-CMP apparatus in 2nd embodiment. It is the 1st figure which showed the time-dependent change of the actual rotation speed of a wafer when brush scrub cleaning is performed in the contact state between two PVA brushes and the surface of the wafer. It is the 2nd figure which showed the time-dependent change of the actual rotation speed of a wafer when brush scrub cleaning is performed in the contact state of two PVA brushes and the wafer surface. It is a flowchart for showing the procedure of the brush scrub cleaning with respect to the wafer after Cu-CMP in 2nd embodiment. It is a figure which shows an example of the manufacturing method of the multilayer wiring process of Cu wiring in the semiconductor device of a multilayer wiring structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cu-CMP apparatus 100 Control part 2 Polishing part 200 Monitoring tool 201 Judgment part 3 Cleaning part C1 1st cleaning unit C2 2nd cleaning unit

Claims (6)

In a method for manufacturing a semiconductor device including a multilayer wiring structure including an upper layer wiring, a lower layer wiring, and a via connecting the upper layer wiring and the lower layer wiring,
Forming a trench on the upper surface of the low dielectric constant film formed on the substrate;
Forming a conductive film containing copper on the upper surface of the low dielectric constant film after forming the trench;
Chemical mechanical polishing the conductive film to form a lower layer wiring in the trench;
Cleaning the substrate after the chemical mechanical polishing;
A step of performing a reduction treatment with ammonia plasma on the upper surface of the low dielectric constant film after cleaning the substrate, and forming a diffusion prevention film thereon;
Forming an interlayer insulating film on the diffusion barrier film;
Opening a via hole corresponding to a via in the interlayer insulating film above the lower layer wiring;
Embedding an antireflection film in the via hole;
Applying a chemically amplified resist on the upper surface of the antireflection film, and forming a resist pattern corresponding to the trench of the upper wiring by photolithography,
The cleaning step performs at least two stages of cleaning,
The first stage performs brush scrub cleaning using an organic acid cleaning chemical.
The second stage is a method for manufacturing a semiconductor device, wherein cleaning is performed using an organic alkali cleaning chemical. In the first stage of the cleaning step, brush scrub cleaning is performed using an organic acid cleaning chemical having a pH of 3 to 4,
2. The method of manufacturing a semiconductor device according to claim 1, wherein the second stage of the cleaning step is performed using an organic alkaline cleaning chemical solution having a pH of 9 to 10. 3. The first stage of the washing process is
Rotating the substrate on which brush scrub cleaning is performed;
When rotation of the substrate starts, detecting a rotation number corresponding to rotation of the substrate for each predetermined period;
Determining whether or not the detected number of revolutions is included within a predetermined range;
As a result of the determination, if the detected number of rotations is outside a predetermined range, a step of stopping brush scrub cleaning of the substrate;
The method for manufacturing a semiconductor device according to claim 1, wherein: A polishing unit that performs chemical mechanical polishing on a substrate having a conductive film containing copper formed on the upper surface of the low dielectric constant film, and forms a lower layer wiring in which the conductive film is embedded in a trench; In a semiconductor manufacturing apparatus comprising a cleaning unit that performs cleaning on a substrate on which the chemical mechanical polishing has been performed,
The cleaning part is
A first cleaning unit that performs brush scrub cleaning using an organic acid cleaning chemical;
A second cleaning unit that performs cleaning using an organic alkaline cleaning chemical;
A semiconductor manufacturing apparatus comprising: The first cleaning unit performs brush scrub cleaning using an organic acid cleaning chemical having a pH of 3 to 4,
The semiconductor manufacturing apparatus according to claim 4, wherein the second cleaning unit performs cleaning using an organic alkali cleaning chemical solution having a pH of 9 to 10. The first cleaning unit includes a rotating unit that rotates a substrate on which brush scrub cleaning is performed,
When the rotation of the substrate starts, a detection unit that detects the number of rotations corresponding to the rotation of the substrate for each predetermined period;
A determination unit that determines whether or not the detected number of rotations is included in a predetermined range;
As a result of the determination, if the detected number of rotations is outside a predetermined range, a stop unit that stops brush scrub cleaning of the substrate;
The semiconductor manufacturing apparatus according to claim 4, further comprising: