JP2015023069A - Substrate cleaning apparatus and substrate cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate cleaning apparatus and a substrate cleaning method that efficiently remove a contaminant such as a particle attached to a substrate surface.SOLUTION: A substrate cleaning apparatus 1 includes a macromolecule supply unit 3 that supplies a macromolecule having polarity to be attached to a substrate 9 and a contaminant, and a physical cleaning unit 4 that performs non-contact physical cleaning of the substrate 9 to which the macromolecule is attached. The contaminant is adsorbed to the substrate 9 by Van der Waals force or the like. The charged macromolecule is attached to the substrate 9 and the contaminant to allow both of the substrate 9 and the contaminant to be charged to the same polarity, thereby reducing adhesive force between the substrate 9 and the contaminant due to electrostatic repulsive force. Physical cleaning is performed while the adhesive force between the substrate 9 and the contaminant is reduced, thereby allowing the contaminant to be efficiently removed with physical damage suppressed.

Description

  The present invention relates to a substrate cleaning apparatus and a substrate cleaning method for removing foreign substances from the surface of a substrate.

  Manufacturing process of substrates for precision electronic devices such as semiconductor wafers, glass substrates for liquid crystal display devices, glass substrates for PDPs, glass substrates for photomasks, substrates for color filters, substrates for recording disks, substrates for solar cells, substrates for electronic paper, etc. In order to remove foreign substances from the surface of the substrate, various cleaning processes are performed.

  For example, in order to remove particles adhering to the substrate surface, a substrate cleaning method using a chemical solution such as SC-1 solution (mixed solution of ammonia water and hydrogen peroxide solution) is conventionally known. A conventional substrate cleaning method using the SC-1 solution is disclosed in Patent Document 1, for example.

JP 2007-281358 A

  As semiconductor devices have been highly integrated and densified in recent years, patterns formed on the substrate surface have become finer. Thereby, it is necessary to remove finer particles.

  As described in Patent Document 1, in the substrate cleaning method using the conventional SC-1 solution, etching loss of the substrate due to ammonia occurs. For this reason, there is a possibility that a device defect may occur in the miniaturized pattern (paragraph 0006). Further, simply supplying the SC-1 solution to the substrate surface cannot effectively remove particles adhering to the substrate surface from the substrate surface (paragraph 0012, FIG. 1).

  On the other hand, as the particle size decreases, the adhesion between the substrate surface and the particles increases. If fine particles are sufficiently removed only by physical cleaning without using the SC-1 solution, the pattern may be collapsed (paragraph 0005).

  The present invention has been made in view of such circumstances, and provides a substrate cleaning apparatus and a substrate cleaning method for efficiently removing contaminants such as particles adhering to the substrate surface while suppressing damage to the pattern. With the goal.

  In order to solve the above-mentioned problems, a first invention of the present application is a substrate cleaning apparatus for removing contaminants attached to a substrate, and supplying a polymer having polarity, which is attached to the substrate and the contaminants. And a physical cleaning unit that performs non-contact physical cleaning on the substrate to which the polymer is attached.

  According to a second aspect of the present invention, in the substrate cleaning apparatus according to the first aspect, the polymer is an ionic surfactant.

  According to a third aspect of the present invention, in the substrate cleaning apparatus according to the second aspect, the ionic surfactant has a molecular weight of 10,000 or less.

  According to a fourth aspect of the present invention, in the substrate cleaning apparatus according to the third aspect, the ionic surfactant has a molecular weight of 1,200 or less.

  According to a fifth invention of the present application, in the substrate cleaning apparatus according to any one of the second to fourth inventions, the ionic surfactant is a polyethyleneimine (PEI) type, a urethane type, a polycarboxylic acid type, an acrylic resin type, It consists of a thiol-based or silane-based surfactant.

  A sixth invention of the present application is the substrate cleaning apparatus according to any one of the first to fifth inventions, wherein the substrate to which the polymer is attached and the contaminant to which the polymer is attached are pure water or an aqueous solution. Has a repulsive force inside.

  A seventh invention of the present application is the substrate cleaning apparatus according to any one of the first to sixth inventions, wherein the physical cleaning unit sprays the atomized cleaning liquid onto the surface of the substrate; A nozzle moving mechanism that scans the fluid nozzle along the surface of the substrate.

  An eighth invention of the present application is the substrate cleaning apparatus according to any one of the first to sixth inventions, wherein the physical cleaning unit supplies a cleaning liquid to the surface of the substrate, a cleaning liquid supply nozzle, and a surface of the substrate. An ultrasonic generator for applying ultrasonic vibration to the supplied cleaning liquid.

  A ninth invention of the present application is the substrate cleaning apparatus according to any one of the first to eighth inventions, further comprising desorption means for desorbing the polymer from the substrate.

  According to a tenth aspect of the present invention, in the substrate cleaning apparatus according to the ninth aspect, the desorption means is a desorption liquid supply unit that supplies a desorption liquid.

  According to an eleventh aspect of the present invention, in the substrate cleaning apparatus according to the tenth aspect, the desorption liquid is a solution in which ozone is dissolved.

  According to a twelfth aspect of the present invention, in the substrate cleaning apparatus according to the ninth aspect, the desorbing means is a UV ozone cleaning unit.

  In a thirteenth aspect of the present invention, in the substrate cleaning apparatus according to the ninth aspect, the desorption means has a heating mechanism for heating the surface of the substrate.

  According to a fourteenth aspect of the present invention, in the substrate cleaning apparatus according to the thirteenth aspect, the heating mechanism heats the surface of the substrate to 400 ° C. or higher.

  According to a fifteenth aspect of the present invention, in the substrate cleaning apparatus according to the thirteenth aspect or the fourteenth aspect, the detaching unit further includes a pressure reducing mechanism that depressurizes a chamber in which the substrate is housed.

  According to a sixteenth aspect of the present invention, there is provided a substrate cleaning method for removing contaminants attached to a substrate, in which a) a polymer supply step for supplying a polymer having polarity to the substrate to which the contaminants are attached; And a physical cleaning step of performing non-contact physical cleaning on the substrate to which the polymer is adhered after the step a).

  According to a seventeenth aspect of the present invention, in the substrate cleaning method according to the sixteenth aspect, the polymer supplied in the step a) is an ionic surfactant.

  According to an eighteenth aspect of the present invention, in the substrate cleaning method according to the seventeenth aspect, the ionic surfactant has a molecular weight of 10,000 or less.

  According to a nineteenth aspect of the present invention, in the substrate cleaning method according to the eighteenth aspect, the ionic surfactant has a molecular weight of 1,200 or less.

  According to a twentieth aspect of the present invention, in the substrate cleaning method according to any one of the seventeenth aspect to the nineteenth aspect, the ionic surfactant is a cationic surfactant in which a hydrophilic group is positively charged in an aqueous solution. In the step a), a neutral aqueous solution of the polymer is supplied to the substrate, and in the step b), non-contact physical cleaning is performed while contacting an acidic aqueous solution with the substrate surface.

  A twenty-first invention of the present application is the substrate cleaning method according to any one of the seventeenth to nineteenth inventions, wherein the ionic surfactant is an anionic surfactant in which a hydrophilic group is negatively charged in an aqueous solution, In the step a), an acidic aqueous solution of the polymer is supplied to the substrate, and in the step b), a non-contact physical cleaning is performed while a neutral aqueous solution or pure water is brought into contact with the substrate surface. .

  A twenty-second invention of the present application is the substrate cleaning method according to any one of the sixteenth to twenty-first inventions, further comprising: c) a desorption treatment step of desorbing the polymer from the substrate after the step b). Prepare.

  According to the first to twenty-second aspects of the present invention, the charged polymer adheres to the substrate and the contaminant, whereby both the substrate and the contaminant are charged to the same polarity. As a result, electrostatic repulsion is generated between the substrate and the contaminant, and the adhesion between the substrate and the contaminant is reduced. By performing physical cleaning in this state, it is possible to efficiently remove contaminants while suppressing physical damage and suppressing damage to the pattern on the substrate.

  According to the second and sixteenth inventions of the present application, the charged hydrophilic group of the ionic surfactant adheres to the surface of the substrate and the contaminant. Thereby, the charged polymer is likely to adhere to the surface of the substrate and the contaminant.

  According to the third and eighteenth aspects of the present application, the molecular weight of the ionic surfactant is 10,000 or less. On the other hand, when the particle size of the contaminant is 600 nanometers or less, the dispersion effect is high when the molecular weight of the ionic surfactant is 10,000 or less. Thereby, fine contaminants of 600 nanometers or less are more reliably removed.

  According to 4th invention and 19th invention of this application, the molecular weight of an ionic surfactant is 1,200 or less. On the other hand, when the particle diameter of the contaminant is 30 nanometers or less, the dispersion effect is high when the molecular weight of the ionic surfactant is 1,200 or less. As a result, fine contaminants of 30 nanometers or less are more reliably removed.

  According to the sixth invention of the present application, it is possible to suppress the contaminant once peeled off from the substrate from adhering to the substrate again. Thereby, a contaminant can be removed more reliably.

  According to the ninth to fifteenth and twenty-second inventions of the present application, the polymer can be detached from the substrate after removing the contaminant.

According to the twentieth invention of the present application, in step a), the substrate and the contaminant come into contact with a neutral aqueous solution. In the case of SiO ₂ or Si ₃ N ₄ , the zeta potential becomes positive when the pH is about 5 or less, and becomes negative when the pH is about 5 or more. Therefore, in the case of the substrate having the SiO ₂ or Si ₃ N ₄ surface, The zeta potential on the solid surface of the substance becomes negative, and the positively charged hydrophilic group of the cationic surfactant is likely to adhere to the solid surface.

  Thereafter, in step b), the zeta potential of the solid surface is changed to around zero (around pH 5) or plus (less than pH 5) by contacting with an acidic aqueous solution. Thereby, since the surface of the substrate and the contaminant is positively charged, they repel each other due to electrostatic repulsion. When physical cleaning is performed in such a state, contaminants can be efficiently removed while suppressing physical damage.

According to the twenty-first invention of the present application, in step a), the substrate and the contaminant come into contact with the acidic aqueous solution. In the case of SiO ₂ or Si ₃ N ₄ , the zeta potential becomes positive when the pH is about 5 or less, and becomes negative when the pH is about 5 or more. Therefore, in the case of the substrate having the SiO ₂ or Si ₃ N ₄ surface, The zeta potential of the solid surface of the substance becomes positive, and the negatively charged hydrophilic group of the anionic surfactant tends to adhere to the solid surface.

  Thereafter, in step b), the zeta potential of the solid surface is changed to minus (pH 5 or more) by contacting with a neutral aqueous solution or pure water. As a result, the substrate and the surface of the contaminant are negatively charged, and thus repel each other due to electrostatic repulsion. When physical cleaning is performed in such a state, contaminants can be efficiently removed while suppressing physical damage.

It is the longitudinal cross-sectional view which showed the structure of the board | substrate washing | cleaning apparatus. It is a block diagram which shows the main control mechanisms of a board | substrate cleaning apparatus. It is the flowchart which showed the flow of the board | substrate cleaning process. It is the figure which showed typically the mode at the time of discharge of a dispersion liquid. It is the figure which showed the mode at the time of physical cleaning typically. It is the figure which showed typically the mode at the time of discharge of a detachment | desorption liquid. It is the figure which showed typically the mode at the time of the discharge of a dispersion liquid when an anionic surfactant is used. It is the figure which showed typically the mode at the time of physical washing | cleaning at the time of using an anionic surfactant. It is the longitudinal cross-sectional view which showed the structure of the board | substrate cleaning apparatus which concerns on one modification. It is the longitudinal cross-sectional view which showed the structure of the board | substrate cleaning apparatus which concerns on another modification. It is the longitudinal cross-sectional view which showed the structure of the board | substrate cleaning apparatus which concerns on another modification.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<1. Substrate cleaning apparatus according to one embodiment>
FIG. 1 is a longitudinal sectional view showing the configuration of the substrate cleaning apparatus 1. FIG. 2 is a block diagram showing a main control mechanism of the substrate cleaning apparatus 1.

  The substrate cleaning apparatus 1 is an apparatus for cleaning a semiconductor wafer 9 contained therein in a semiconductor manufacturing process. As shown in FIGS. 1 and 2, the substrate cleaning apparatus 1 of the present embodiment includes a holding unit 2, a polymer supply unit 3, a physical cleaning unit 4, a detachment liquid supply unit 5, a drainage collection unit 6, and A control unit 10 is provided.

  The holding unit 2 is a mechanism that holds the semiconductor wafer 9 that is a substantially disk-shaped substrate substantially horizontally. The holding part 2 includes a substantially disk-shaped base part 21, a plurality of chuck pins 22 provided on the upper surface of the base part 21, and a rotation mechanism 23 that rotates the base part 21.

  The plurality of chuck pins 22 are arranged at equiangular intervals on the upper surface in the vicinity of the peripheral edge portion of the base portion 21. The semiconductor wafer 9 is held by the chuck pins 22 with the device region where the pattern is formed facing the upper surface side. Each chuck pin 22 contacts the lower surface and the outer peripheral end surface of the peripheral edge of the semiconductor wafer 9 and supports the semiconductor wafer 9 at a position above the upper surface of the base portion 21 through a gap.

  The holding unit 2 holds the semiconductor wafer 9 so that the approximate center of the semiconductor wafer 9 and the central axis 20 of the rotation mechanism 23 overlap. The rotation mechanism 23 can be realized by a motor, for example. When the rotation mechanism 23 is operated, the base portion 21, the chuck pins 22, and the semiconductor wafer 9 rotate about the central axis 20.

  The polymer supply unit 3 includes a polymer supply nozzle 31, a first pipe 32, a polymer supply source 33, and a first on-off valve 34. The polymer supply nozzle 31 is a nozzle for discharging the dispersion liquid onto the upper surface of the semiconductor wafer 9 held by the holding unit 2. The dispersion contains an ionic surfactant S, which is a polar polymeric surfactant. The polymer supply nozzle 31 is connected to the polymer supply source 33 through a first pipe 32. A first opening / closing valve 34 is inserted in the middle of the path of the first pipe 32. For this reason, when the first on-off valve 34 is opened, the dispersion liquid is supplied from the polymer supply source 33 to the polymer supply nozzle 31 through the first pipe 32. Then, the dispersion liquid is discharged from the polymer supply nozzle 31 onto the upper surface of the semiconductor wafer 9. As a result, the ionic surfactant S contained in the dispersion adheres to the semiconductor wafer 9 and the particles that are contaminants attached to the semiconductor wafer 9. The dispersion supplied from the polymer supply source 33 may be a liquid stock solution of the ionic surfactant S, or may be a liquid or solid aqueous solution of the ionic surfactant S.

  As the ionic surfactant S, for example, a polyimine surfactant such as polyethyleneimine (PEI) or a silane surfactant such as 3-aminopropyltriethoxysilane is used. Further, as the ionic surfactant S, a urethane surfactant, a polycarboxylic acid surfactant, an acrylic resin surfactant, or a thiol surfactant may be used.

  The ionic surfactant S preferably has a molecular weight of 10,000 or less. Then, the dispersion effect is large for particles having a particle diameter of 600 nanometers or less. The ionic surfactant S more preferably has a molecular weight of 1,200 or less. Then, the dispersion effect is large for particles having a particle diameter of 30 nanometers or less.

  For example, as described in the 54th Theoretical and Applied Mechanics Lecture Proceedings p45-48 (Hidehiro Kamiya, 2005), the particle size of a polyethyleneimine (PEI) dispersant having a molecular weight of 300-70,000 is added. The apparent viscosity of different alumina particle slurries is such that for alumina particles having a particle size of submicron, the viscosity becomes minimal at a molecular weight of about 10,000, and for alumina particles having a particle size of 7 to 30 nanometers. Indicates a minimum value of the viscosity of the dispersant having a molecular weight of 1,200.

  Thus, by making the molecular weight of the ionic surfactant S 10,000 or less or 1,200 or less, the adhesion between the semiconductor wafer and the particles can be effectively reduced with respect to finer particles. .

  As the solvent for dissolving the ionic surfactant S, for example, pure water (deionized water, DIW) or carbonated water (CO2 aqueous solution) is used. By using the ionic surfactant S dissolved in various solvents, the pH of the dispersion can be adjusted.

  The physical cleaning unit 4 includes a cleaning nozzle 41, a second pipe 42, a third pipe 43, a cleaning liquid supply source 44, a gas supply source 45, a second on-off valve 46, a third on-off valve 47, and a nozzle moving mechanism 48. The cleaning nozzle 41 is a nozzle for spraying mist-like cleaning liquid droplets onto the upper surface of the semiconductor wafer 9 held by the holding unit 2. The cleaning nozzle 41 is a so-called two-fluid nozzle that generates mist-like cleaning liquid droplets by mixing the cleaning liquid supplied from the cleaning liquid supply source 44 and the gas supplied from the gas supply source. That is, the physical cleaning unit 4 is a so-called two-fluid cleaning device.

  The cleaning nozzle 41 is connected to a cleaning liquid supply source 44 through a second pipe 42. A second opening / closing valve 46 is inserted in the middle of the path of the second pipe 42. Further, the cleaning nozzle 41 is connected to the gas supply source 45 through a third pipe 43. A third on-off valve 47 is interposed in the middle of the path of the third pipe 43. Therefore, when the second on-off valve 46 and the third on-off valve 47 are opened, the cleaning liquid is supplied from the cleaning liquid supply source 44 to the cleaning nozzle 41 through the second pipe 42, and from the gas supply source 45 to the third pipe 43. Gas is supplied through. As a result, a mist-like cleaning liquid droplet is sprayed from the cleaning nozzle 41 onto the upper surface of the semiconductor wafer 9. That is, the physical cleaning unit 4 performs non-contact physical cleaning on the semiconductor wafer 9 by spraying the atomized cleaning liquid onto the upper surface of the semiconductor wafer 9.

  The cleaning nozzle 41 can be moved in the horizontal direction by a nozzle moving mechanism 48. Therefore, the cleaning nozzle 41 can spray the cleaning liquid on the upper surface of the semiconductor wafer 9 while scanning the upper side of the semiconductor wafer 9. As a result, the entire upper surface of the semiconductor wafer 9 can be uniformly physically cleaned.

  For example, pure water or carbonated water is used as the cleaning liquid supplied from the cleaning liquid supply source 44. As the gas supplied from the gas supply source 45, for example, an inert gas such as nitrogen gas, clean air, or carbon dioxide gas is used. The cleaning liquid and the gas are selected in consideration of the type of ionic surfactant S to be attached to the semiconductor wafer 9.

  The desorption liquid supply unit 5 is a desorption unit that desorbs the ionic surfactant S adhering to the upper surface of the semiconductor wafer 9. The detachment liquid supply unit 5 includes a detachment liquid supply nozzle 51, a fourth pipe 52, a detachment liquid supply source 53, and a fourth on-off valve 54. The detachment liquid supply nozzle 51 is a nozzle for discharging the detachment liquid onto the upper surface of the semiconductor wafer 9 held by the holding unit 2. The detachment liquid supply nozzle 51 is connected to the detachment liquid supply source 53 through a fourth pipe 52. A fourth on-off valve 54 is inserted in the middle of the route of the fourth pipe 52. Therefore, when the fourth on-off valve 54 is opened, the desorbed liquid is supplied from the desorbed liquid supply source 53 to the desorbed liquid supply nozzle 51 through the fourth pipe 52. Then, the detachment liquid is discharged from the detachment liquid supply nozzle 51 onto the upper surface of the semiconductor wafer 9. Thereby, the ionic surfactant S adhering to the semiconductor wafer 9 is desorbed. The desorption liquid is, for example, a solution in which ozone is dissolved, that is, ozone water.

  The drainage collecting part 6 is a part for collecting the used dispersion liquid, cleaning liquid, and desorbed liquid. The drainage collection unit 6 includes a cup 61 that annularly surrounds the semiconductor wafer 9 held by the holding unit 2, and a fifth pipe 62 that is connected to the bottom of the cup 61 through a flow path. The dispersion liquid, the cleaning liquid, and the desorption liquid are supplied to the semiconductor wafer 9 and then collected in the cup 61. Thereafter, the dispersion liquid, the cleaning liquid, and the desorbing liquid are discharged to the outside of the substrate cleaning apparatus 1 through the fifth pipe 62, and are subjected to a regeneration process or a disposal process.

  As shown in FIG. 2, the control unit 10 includes the chuck pin 22, the rotation mechanism 23, the first on-off valve 34, the second on-off valve 46, the third on-off valve 47, the nozzle moving mechanism 48, and the fourth on-off valve 54. Various operation mechanisms provided in the substrate cleaning apparatus 1 are controlled. The control unit 10 includes a CPU 101 that performs various arithmetic processes, and a memory 102 that stores various programs and various information. When the CPU 101 executes a predetermined processing program with reference to the memory 102, the cleaning process of the semiconductor wafer 9 in the substrate cleaning apparatus 1 proceeds.

  The holding unit 2, the polymer supply unit 3, the physical cleaning unit 4, the desorbed liquid supply unit 5, and the drainage collecting unit 6 described above are disposed inside the chamber 8 in which the temperature and cleanliness are controlled. The The control unit 10 also controls operations of a shutter mechanism for opening and closing a loading / unloading port provided in the chamber 8 and a transfer mechanism for loading and unloading the semiconductor wafer 9 via the loading / unloading port.

<2. Substrate cleaning process>
Next, a substrate cleaning process using the substrate cleaning apparatus 1 will be described. FIG. 3 is a flowchart showing the flow of the substrate cleaning process in the substrate cleaning apparatus 1. FIG. 4 is a diagram schematically showing a state when the dispersion liquid is discharged. FIG. 5 is a diagram schematically showing a state during physical cleaning. FIG. 6 is a diagram schematically showing a state when discharging the desorbing liquid.

  In this substrate cleaning apparatus 1, a substrate cleaning process is performed for the purpose of removing particles 91 adhering to the surface of the semiconductor wafer 9. In the substrate cleaning apparatus 1, when performing the cleaning process of the semiconductor wafer 9, the control unit 10 controls the operation of each unit in the substrate cleaning apparatus 1. As a result, the following operation proceeds. Hereinafter, the operation of each unit will be described with reference to FIG.

  The substrate cleaning apparatus 1 first carries the semiconductor wafer 9 into the chamber 8 by a predetermined transfer mechanism. At the time of loading, the loading / unloading port of the chamber 8 is opened, and the semiconductor wafer 9 is loaded from the loading / unloading port into the chamber 8. In addition, the plurality of chuck pins 22 of the holding unit 2 are opened outward, and the semiconductor wafer 9 is disposed above the base unit 21. Then, the semiconductor wafer 9 is transferred from the predetermined transport mechanism to the holding unit 2 by closing the plurality of chuck pins 22 inward. The semiconductor wafer 9 is held by the holding unit 2 in a horizontal posture with the device surface facing the upper surface (step S1). When the transfer of the semiconductor wafer 9 is completed, the loading / unloading port of the chamber 8 is closed.

  Next, the substrate cleaning apparatus 1 opens the first on-off valve 34. Thereby, as shown in FIG. 4, the dispersion liquid 30 is discharged from the polymer supply nozzle 31 (step S2). The dispersion liquid 30 is discharged from the polymer supply nozzle 31 toward the approximate center of the upper surface of the semiconductor wafer 9. Further, the rotation of the base portion 21 is started by operating the rotation mechanism 23 simultaneously with the start of the discharge of the dispersion liquid 30 or after the start of the discharge. Thereby, the dispersion liquid is applied to the entire upper surface of the semiconductor wafer 9.

  The ionic surfactant S of this embodiment is a polyethyleneimine (PEI) surfactant having a molecular weight of 1,200. Polyethyleneimine surfactants are cationic (cationic) type surfactants whose hydrophilic groups are positively charged in an aqueous solution. The dispersion 30 is an aqueous solution in which the ionic surfactant S is dissolved in pure water. For this reason, the dispersion 30 is neutral around pH 7. Further, the hydrophilic group of the ionic surfactant S is positively charged.

In the semiconductor wafer 9 of this embodiment, the surface of the device surface is covered with a SiO ₂ film. Further, most of the particles 91 that are contaminants to be removed are SiO ₂ particles. The zeta potential on the surface of SiO ₂ changes in the vicinity of pH 5 as described in, for example, Ultra Clean ULSI Technology (Advanced Electronics Series) p162-164 (Tadahiro Omi, 1995). The zeta potential on the SiO ₂ surface is positive on the acidic side from pH 5, that is, below pH 5, and the zeta potential on the SiO ₂ surface is negative on the alkaline side from pH 5, ie, at pH 5 or higher.

  Therefore, since the dispersion liquid 30 of this embodiment has a pH of around 7, when the dispersion liquid 30 is in contact with the semiconductor wafer 9, the zeta potential on the surfaces of the semiconductor wafer 9 and the particles 91 is negative.

  The semiconductor wafer 9 and the particles 91 are physically adsorbed by van der Waals force or the like. By bringing the dispersion liquid into contact with the entire upper surface of the semiconductor wafer 9, the ionic surfactant S adheres to the surface of the semiconductor wafer 9 and the surface of the particles 91. At this time, as described above, the zeta potentials of the semiconductor wafer 9 and the particles 91 are negative, and the ionic surfactant S is positively charged. For this reason, the ionic surfactant S is attracted to the semiconductor wafer 9 and the particles 91, and the ionic surfactant S efficiently adheres to the surfaces of the semiconductor wafer 9 and the particles 91.

  When the ionic surfactant S adheres to the surfaces of the semiconductor wafer 9 and the particles 91, the surfaces of the semiconductor wafer 9 and the particles 91 are positively charged. When both the semiconductor wafer 9 and the particle 91 are charged to the same polarity, an electrostatic repulsive force acts between the semiconductor wafer 9 and the particle 91. Therefore, the adhesive force between the semiconductor wafer 9 and the particles 91 is reduced. As a result, the particles 91 are peeled off from the semiconductor wafer 9 or are easily peeled off.

  In step S2, the positive charges of the hydrophilic groups of the ionic surfactant S are partially canceled by the negative zeta potential of the semiconductor wafer 9 and the particles 91. However, since the charge amount of the ionic surfactant S adhering to the surfaces of the semiconductor wafer 9 and the particles 91 exceeds the zeta potential, a positive electrostatic repulsive force acts between the semiconductor wafer 9 and the particles 91.

  After the dispersion liquid is supplied to the entire upper surface of the semiconductor wafer 9, the substrate cleaning apparatus 1 closes the first on-off valve 34 and stops the discharge of the dispersion liquid 30 from the polymer supply nozzle 31.

  Subsequently, the substrate cleaning apparatus 1 opens the second on-off valve 46 and the third on-off valve 47. Thereby, as shown in FIG. 5, droplets of the mist-like cleaning liquid 40 are sprayed from the cleaning nozzle 41 onto the upper surface of the semiconductor wafer 9. The cleaning nozzle 41 sprays the cleaning liquid 40 on the upper surface of the semiconductor wafer 9 while scanning the upper side of the semiconductor wafer 9 rotated by the rotating mechanism 23 in the horizontal direction. Thereby, non-contact physical cleaning is performed on the entire upper surface of the semiconductor wafer 9 (step S3).

  The cleaning liquid 40 of this embodiment is carbonated water having a pH of around 5. For this reason, when the cleaning liquid 40 comes into contact with the surfaces of the semiconductor wafer 9 and the particles 91, the zeta potential of the semiconductor wafer 9 and the particles 91 becomes approximately zero. As a result, the zeta potential that cancels the charge of the ionic surfactant S becomes zero, and the electrostatic repulsion between the semiconductor wafer 9 and the particles 91 increases. That is, the repulsive force between the semiconductor wafer 9 and the particles 91 is increased.

  The cleaning liquid 40 may have a pH of 5 or less. As a result, the zeta potentials of the semiconductor wafer 9 and the particles 91 become positive. In this case, since both the zeta potential of the semiconductor wafer 9 and the particle 91 and the charge of the ionic surfactant S are positive, the electrostatic repulsion between the semiconductor wafer 9 and the particle 91 is further increased. That is, the repulsive force between the semiconductor wafer 9 and the particles 91 is further increased.

  In this way, by performing physical cleaning in a state in which a repulsive force is generated between the semiconductor wafer 9 and the particles 91, the pollutant can be obtained without increasing the cleaning time of the physical cleaning or increasing the cleaning power. The removal power can be increased. On the contrary, by sufficiently increasing the repulsive force between the semiconductor wafer 9 and the particles 91, the cleaning time of physical cleaning can be shortened or the cleaning power can be reduced. That is, by suppressing physical damage to a minimum, it is possible to reliably remove the particles 91 that are contaminants while suppressing damage to the pattern on the semiconductor wafer 9.

  As described above, in steps S2 and S3, the semiconductor wafer 9 to which the ionic surfactant S adheres and the particles 91 to which the ionic surfactant S adheres have a repulsive force in pure water or an aqueous solution. doing. As a result, the particles 91 once separated from the semiconductor wafer 9 are prevented from reattaching to the semiconductor wafer 9. Therefore, the particles 91 adhering to the semiconductor wafer 9 can be more reliably removed.

  When spraying of the cleaning liquid 40 is completed on the entire upper surface of the semiconductor wafer 9, the substrate cleaning apparatus 1 closes the second on-off valve 46 and the third on-off valve 47 and stops the discharge of the cleaning liquid 40 from the cleaning nozzle 41. To do.

  Thereafter, the substrate cleaning apparatus 1 opens the fourth on-off valve 54. As a result, as shown in FIG. 6, the detachment liquid 50 is discharged from the detachment liquid supply nozzle 51 onto the upper surface of the semiconductor wafer 9. Since the semiconductor wafer 9 is rotated by the rotation mechanism 23, the desorption liquid 50 is efficiently supplied to the entire upper surface of the semiconductor wafer 9. In the present embodiment, the desorbing liquid 50 is ozone water.

  When the desorbing liquid 50 comes into contact with the surface of the semiconductor wafer 9 to which the ionic surfactant S is adhered, the active oxygen separated from ozone in the desorbing liquid 50 is chemically bonded to the ionic surfactant S. Then, the ionic surfactant S is desorbed from the semiconductor wafer 9 (step S4). At the same time, the ionic surfactant S is decomposed into substances such as carbon dioxide and water.

  When the ionic surfactant S on the upper surface of the semiconductor wafer 9 is desorbed, the substrate cleaning apparatus 1 closes the fourth on-off valve 54 and stops discharging the desorbing liquid 50 from the desorbing liquid supply nozzle 51. . After stopping the discharge of the detaching liquid 50, the substrate cleaning apparatus 1 increases the rotation speed of the rotation mechanism 23, rotates the semiconductor wafer 9 at a high speed for a predetermined time, and performs spin drying. Thereby, the desorbed liquid 50 remaining on the semiconductor wafer 9 is removed by centrifugal force. Note that the drying efficiency may be improved by supplying a dry gas to the surface of the semiconductor wafer 9 during spin drying.

  After the surface of the semiconductor wafer 9 is dried, the substrate cleaning apparatus 1 stops the operation of the rotation mechanism 23 and stops the rotation of the base portion 21 and the semiconductor wafer 9.

  Finally, the substrate cleaning apparatus 1 opens the loading / unloading port of the chamber 8 and unloads the semiconductor wafer 9 to the outside of the chamber 8 by a predetermined transfer mechanism (step S5).

<3. Modification>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

  In the above embodiment, the ionic surfactant is a cationic surfactant, but the present invention is not limited to this. The ionic surfactant may be an anionic (anionic) type surfactant in which a hydrophilic group is negatively charged in an aqueous solution.

  FIG. 7 schematically shows a state when the dispersion liquid is discharged when an anionic surfactant is used as the ionic surfactant Sa in the substrate cleaning process using the substrate cleaning apparatus 1 described above. FIG. FIG. 8 is a diagram schematically showing a state during physical cleaning in the example of FIG.

  In the example of FIG. 7, the ionic surfactant Sa contained in the dispersant is a polycarboxylic acid anionic surfactant having a molecular weight of 10,000 or less. The dispersion 30a is an aqueous solution in which an ionic surfactant Sa is dissolved in carbonated water. For this reason, the dispersion liquid 30a is acidic and has a pH of less than 5. Further, the hydrophilic group of the ionic surfactant Sa is negatively charged.

  On the other hand, since the dispersion liquid 30a is less than pH 5, when the dispersion liquid 30a comes into contact with the semiconductor wafer 9 and the particle 91, the zeta potential of the semiconductor wafer 9 and the particle 91 becomes positive, and the ionic surfactant Sa is Attracted to the particles 91. Therefore, the ionic surfactant Sa adheres efficiently to the surfaces of the semiconductor wafer 9 and the particles 91.

  When the ionic surfactant Sa adheres to the surfaces of the semiconductor wafer 9 and the particles 91, the surfaces of the semiconductor wafer 9 and the particles 91 are negatively charged. When both the semiconductor wafer 9 and the particle 91 are charged to the same polarity, an electrostatic repulsive force acts between the semiconductor wafer 9 and the particle 91. Therefore, the particles 91 are peeled from the semiconductor wafer 9 or are easily peeled off.

  After the dispersion liquid 30a is supplied to the entire upper surface of the semiconductor wafer 9 and the ionic surfactant Sa adheres to the surfaces of the semiconductor wafer 9 and the particles, the cleaning liquid 40a is applied to the upper surface of the semiconductor wafer 9 as shown in FIG. Sprayed and physically cleaned.

  In the example of FIG. 8, the cleaning liquid 40a used for physical cleaning is pure water having a pH of 7. For this reason, when the cleaning liquid 40a comes into contact with the surfaces of the semiconductor wafer 9 and the particles 91, the zeta potential of the semiconductor wafer 9 and the particles 91 turns negative. Thereby, the electrostatic repulsion between the semiconductor wafer 9 and the particles 91 is increased. That is, the repulsive force between the semiconductor wafer 9 and the particles 91 is increased. As the cleaning liquid 40a, a neutral aqueous solution around pH 7 may be used instead of pure water.

  In this way, even if the ionic surfactant is an anionic surfactant, the pollutant can be obtained by performing physical cleaning in a state where a repulsive force is generated between the semiconductor wafer 9 and the particles 91. The removal power can be increased. That is, it is possible to reliably remove the particles 91 that are contaminants while minimizing physical damage and suppressing damage to the pattern on the semiconductor wafer 9.

  FIG. 9 is a longitudinal sectional view showing a configuration of a substrate cleaning apparatus 1b according to a modification. In the example of FIG. 9, the physical cleaning unit 4b is an ultrasonic cleaning device instead of the two-fluid cleaning device. The physical cleaning unit 4b includes a cleaning nozzle 41b, a second pipe 42b, a cleaning liquid supply source 44b, a second on-off valve 46b, and an ultrasonic transducer 49b.

  The cleaning nozzle 41b is a cleaning liquid supply nozzle that is connected to the cleaning liquid supply source 44b through the second pipe 42b. A second opening / closing valve 46b is inserted in the middle of the path of the second pipe 42b. The cleaning nozzle 41b incorporates an ultrasonic transducer 49b that generates ultrasonic vibrations. When the ultrasonic vibrator 49b is driven, ultrasonic vibration is added to the cleaning liquid inside the cleaning nozzle 41b. The ultrasonic vibration may be, for example, a low frequency vibration of 10 kHz to 1 MHz or a high frequency vibration of 1 MHz or more.

  For this reason, when the second on-off valve 46b is opened and the ultrasonic vibrator 49b is driven, the cleaning liquid to which the ultrasonic vibration is added is supplied from the cleaning nozzle 41b to the upper surface of the semiconductor wafer 9b. The particles adhering to the surface of the semiconductor wafer 9b are released from the surface of the semiconductor wafer 9b by the energy of ultrasonic vibration. That is, the physical cleaning unit 4b performs non-contact physical cleaning using ultrasonic vibration on the semiconductor wafer 9b.

  As described above, the physical cleaning unit of the substrate cleaning apparatus of the present invention is a two-fluid cleaning apparatus, an ultrasonic cleaning apparatus, or other cleaning apparatus as long as it is a device that performs non-contact physical cleaning on a semiconductor wafer. Also good.

  FIG. 10 is a longitudinal sectional view showing a configuration of a substrate cleaning apparatus 1c according to another modification. In the example of FIG. 10, the substrate cleaning apparatus 1 c includes a UV ozone cleaning unit 5 c as a desorbing unit instead of the desorbing liquid supply unit.

  The UV ozone cleaning unit 5c performs UV ozone cleaning on the surface of the semiconductor wafer 9c. The UV ozone cleaning unit 5c includes a UV lamp 55c, an oxygen supply pipe 56c, an oxygen supply source 57c, and an oxygen supply opening / closing valve 58c. The UV lamp 55c is disposed above the semiconductor wafer 9c.

  One end of the oxygen supply pipe 56c is connected to the oxygen supply source 57c, and the other end is an oxygen supply port 561c disposed in the chamber 8c. An oxygen supply opening / closing valve 58c is inserted in the middle of the oxygen supply pipe 56c. Therefore, when the oxygen supply opening / closing valve 58c is opened, oxygen is supplied from the oxygen supply port 561c into the chamber 8c. Oxygen supplied into the chamber 8c generates ozone when irradiated with ultraviolet rays. When the oxygen concentration in the chamber 8c is sufficient for performing UV ozone cleaning, the oxygen supply pipe 56c, the oxygen supply source 57c, and the oxygen supply opening / closing valve 58c may be omitted.

  When the UV lamp 55c irradiates the surface of the semiconductor wafer 9c with ultraviolet light, the ionic surfactant attached to the surface of the semiconductor wafer 9c is decomposed, and the ionic surfactant is desorbed from the surface of the semiconductor wafer 9c. At the same time, active oxygen separated from ozone generated by ultraviolet rays chemically binds to the ionic surfactant and decomposes into volatile substances such as carbon dioxide and water. Thus, even if the desorption means is a UV ozone cleaning unit, the ionic surfactant attached to the semiconductor wafer can be removed.

  FIG. 11 is a longitudinal sectional view showing a configuration of a substrate cleaning apparatus 1d according to another modification. In the example of FIG. 11, the substrate cleaning apparatus 1d has a heating mechanism 7d and a pressure reducing mechanism 70d as desorption means instead of the desorption liquid supply unit.

  The heating mechanism 7d includes a heating nozzle 71d, a heating gas supply pipe 72d, a heating gas supply source 73d, a heater 74d, and a heating on-off valve 75d. The heating nozzle 71d is a nozzle for discharging heated heating gas onto the upper surface of the semiconductor wafer 9d. The heating nozzle 71d is connected to a heating gas supply source 73d through a flow path via a heating gas supply pipe 72d. Further, a heater 74d and a heating on-off valve 75d are interposed in the course of the heating gas supply pipe 72d. For example, an inert gas such as nitrogen gas is used as the heating gas.

  The decompression mechanism 70d discharges the atmosphere in the chamber 8d to the outside, and decompresses the inside of the chamber 8d. The decompression mechanism 70d has an exhaust pipe 76d and a decompression pump 77d. One end of the exhaust pipe 76d is connected to the internal space of the chamber 8d, and the other end has an exhaust port 761d. A decompression pump 77d is connected midway along the exhaust pipe 76d. When the decompression pump 77d is driven, the atmosphere inside the chamber 8d is exhausted from the exhaust port 761d through the exhaust pipe 76d. Thereby, the atmosphere in the chamber 8d is decompressed.

  When the heating on-off valve 75d is opened while the inside of the chamber 8d is decompressed, the heating gas heated by the heater 74d is supplied from the heating gas supply source 73d through the heating gas supply pipe 72d to the heating nozzle 71d. Is supplied. Then, the heated heating gas is discharged from the heating nozzle 71d onto the upper surface of the semiconductor wafer 9d. Thereby, the upper surface of the semiconductor wafer 9d is heated. At this time, the heating gas discharged from the heating nozzle 71d is desirably 400 ° C. or higher.

  Substances adhering to the solid surface have the property of sequentially desorbing from those with weak adhesion as the temperature of the solid surface increases. For this reason, when the upper surface of the semiconductor wafer 9d is heated, the ionic surfactant attached to the semiconductor wafer 9d is desorbed. The ionic surfactant desorbed from the surface of the semiconductor wafer 9d and suspended in the atmosphere in the chamber 8d is discharged from the exhaust port 761d together with the atmosphere in the chamber 8d. By desorbing the ionic surfactant while reducing the pressure in the chamber 8d, it is possible to prevent the desorbed ionic surfactant from being reattached. Thus, even if the desorption means is a heating mechanism and a decompression mechanism, the ionic surfactant attached to the semiconductor wafer can be removed.

  As in the example of FIG. 10 and the example of FIG. 11, the substrate cleaning apparatus of the present invention is not limited to the desorbing liquid supply unit, and may be UV as long as the ionic surfactant attached to the semiconductor wafer is desorbed. You may have an ozone washing | cleaning part, a heating mechanism, and another structure.

Further, the present invention is not limited to a semiconductor wafer whose substrate to be cleaned has a SiO ₂ surface. In the above embodiment, since the surface of the semiconductor wafer is SiO ₂ , when the ionic surfactant is a cation type, an aqueous solution having a pH greater than 5 is used for the dispersion and an aqueous solution having a pH of 5 or less is used for the cleaning liquid. . Further, when the ionic surfactant is an anionic type, an aqueous solution having a pH of less than 5 is used for the dispersion, and pure water or an aqueous solution having a pH of more than 5 is used for the cleaning liquid. This is because the zeta potential of SiO ₂ is reversed between positive and negative in the vicinity of pH 5. The dispersion liquid and the cleaning liquid are selected in consideration of the pH dependence of the zeta potential of the substrate to be cleaned.

  In the above-described embodiment or modification, the polymer supply source 33, the cleaning liquid supply sources 44 and 44b, the gas supply source 45, the desorption liquid supply source 53, and the oxygen supply source 57c are part of the substrate cleaning apparatus. However, utility facilities in the factory may be used for these supply sources.

  In addition, the substrate cleaning apparatus of the above-described embodiment or modification performs a semiconductor wafer cleaning process in a single chamber. However, the substrate cleaning apparatus of the present invention includes a plurality of such chambers. These semiconductor wafers may be processed in parallel in a plurality of chambers.

  Further, the above substrate cleaning apparatus is used in the manufacturing process of a semiconductor wafer, but the substrate cleaning apparatus and the substrate cleaning method of the present invention are for a glass substrate for a liquid crystal display device, a glass substrate for a PDP, and a photomask. Other precision electronic device substrates such as a glass substrate, a color filter substrate, a recording disk substrate, and a solar cell substrate may be processed.

  Moreover, about the detailed structure of a board | substrate cleaning apparatus, you may differ from the shape shown by each figure of this application. Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

1, 1b, 1c Substrate cleaning device 2 Holding unit 3 Polymer supply unit 4, 4b Physical cleaning unit 5 Desorbed liquid supply unit 5c Ozone cleaning unit 6 Drained liquid collection unit 7d Heating mechanism 8, 8c, 8d Chamber 9, 9b , 9c, 9d Semiconductor wafer 10 Control unit 30, 30a Dispersion liquid 31 Polymer supply nozzle 40, 40a Cleaning liquid 41, 41b Cleaning nozzle 44, 44b Cleaning liquid supply source 45 Gas supply source 48 Nozzle moving mechanism 49b Ultrasonic vibrator 50 Desorption Liquid 51 Desorption liquid supply nozzle 55c UV lamp 57c Oxygen supply source 70d Depressurization mechanism 71d Heating nozzle 73d Heating gas supply source 74d Heater 91 Particle 561c Oxygen supply port S, Sa Ionic surfactant

Claims (22)

In a substrate cleaning apparatus for removing contaminants attached to a substrate,
A polymer supply unit for supplying a polymer having polarity, which is attached to a substrate and a contaminant;
A physical cleaning unit that performs non-contact physical cleaning on the substrate to which the polymer is attached;
A substrate cleaning apparatus comprising: The substrate cleaning apparatus according to claim 1,
The substrate cleaning apparatus, wherein the polymer is an ionic surfactant. The substrate cleaning apparatus according to claim 2,
The substrate cleaning apparatus, wherein the ionic surfactant has a molecular weight of 10,000 or less. The substrate cleaning apparatus according to claim 3,
The substrate cleaning apparatus, wherein the ionic surfactant has a molecular weight of 1,200 or less. In the substrate cleaning apparatus according to any one of claims 2 to 4,
The ionic surfactant is
Polyethyleneimine (PEI) system,
Urethane,
Polycarboxylic acid,
Acrylic resin,
Thiol,
Or
Silane,
A substrate cleaning apparatus comprising any of the above surfactants. In the substrate cleaning apparatus according to any one of claims 1 to 5,
The substrate cleaning apparatus, wherein the substrate to which the polymer is attached and the contaminant to which the polymer is attached have a repulsive force in pure water or an aqueous solution. In the substrate cleaning apparatus according to any one of claims 1 to 6,
The physical cleaning unit
A two-fluid nozzle that sprays atomized cleaning liquid onto the surface of the substrate;
A nozzle moving mechanism that scans the two-fluid nozzle along the surface of the substrate;
A substrate cleaning apparatus. In the substrate cleaning apparatus according to any one of claims 1 to 6,
The physical cleaning unit
A cleaning liquid supply nozzle for supplying a cleaning liquid to the surface of the substrate;
An ultrasonic generator for applying ultrasonic vibration to the cleaning liquid supplied to the surface of the substrate;
A substrate cleaning apparatus. In the substrate cleaning apparatus according to any one of claims 1 to 8,
A substrate cleaning apparatus further comprising desorption means for desorbing the polymer from the substrate. The substrate cleaning apparatus according to claim 9, wherein
The desorption means is a substrate cleaning apparatus which is a desorption liquid supply unit for supplying a desorption liquid. The substrate cleaning apparatus according to claim 10,
The substrate cleaning apparatus, wherein the desorption liquid is a solution in which ozone is dissolved. The substrate cleaning apparatus according to claim 9, wherein
The desorption means is a substrate cleaning apparatus which is a UV ozone cleaning unit. The substrate cleaning apparatus according to claim 9, wherein
The desorption means is a substrate cleaning apparatus having a heating mechanism for heating the surface of the substrate. The substrate cleaning apparatus according to claim 13,
The heating mechanism is a substrate cleaning apparatus that heats the surface of the substrate to 400 ° C. or higher. The substrate cleaning apparatus according to claim 13 or 14,
The desorption means is a substrate cleaning apparatus further comprising a depressurization mechanism for depressurizing a chamber in which the substrate is housed. In the substrate cleaning method for removing contaminants attached to the substrate,
a) a polymer supplying step for supplying a polymer having polarity to a substrate to which a contaminant is attached;
b) After the step a), a physical cleaning step of performing non-contact physical cleaning on the substrate to which the polymer is attached;
A substrate cleaning method comprising: The substrate cleaning method according to claim 16, wherein
The substrate cleaning method, wherein the polymer supplied in the step a) is an ionic surfactant. The substrate cleaning method according to claim 17,
The substrate cleaning method, wherein the ionic surfactant has a molecular weight of 10,000 or less. The substrate cleaning method according to claim 18, wherein
The substrate cleaning method, wherein the ionic surfactant has a molecular weight of 1,200 or less. In the substrate cleaning method according to any one of claims 17 to 19,
The ionic surfactant is a cationic surfactant whose hydrophilic group is positively charged in an aqueous solution,
Supplying a neutral aqueous solution of the polymer to the substrate in step a);
And,
A substrate cleaning method, wherein in step b), non-contact physical cleaning is performed while contacting an acidic aqueous solution with the substrate surface. In the substrate cleaning method according to any one of claims 17 to 19,
The ionic surfactant is an anionic surfactant whose hydrophilic group is negatively charged in an aqueous solution,
In step a), an acidic aqueous solution of the polymer is supplied to the substrate,
And,
A substrate cleaning method, wherein in step b), non-contact physical cleaning is performed while a neutral aqueous solution or pure water is brought into contact with the substrate surface. The substrate cleaning method according to any one of claims 16 to 21,
c) A substrate cleaning method further comprising a desorption treatment step of desorbing the polymer from the substrate after the step b).

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