JP5865073B2 - Substrate processing apparatus and substrate processing method - Google Patents

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for processing a substrate.

  Conventionally, in a manufacturing process of a semiconductor substrate (hereinafter simply referred to as “substrate”), various processes are performed on a substrate having an insulating film such as an oxide film using a substrate processing apparatus. For example, a cleaning process is performed to remove particles and the like attached on the surface of the substrate by supplying a cleaning liquid to the surface of the substrate.

  In Patent Document 1, a liquid such as deionized water (DIW) is supplied to the surface of the substrate, the liquid is cooled with a cooling gas, frozen, and then thawed and removed with a rinse liquid. A technique for cleaning the surface is disclosed. Patent Document 2 discloses a technique in which deionized water cooled to room temperature is supplied to the surface of the substrate and frozen with a cooling gas in the above-described freeze cleaning. Patent Document 2 describes that the cooling temperature of deionized water is preferably lower than 10 ° C., and considering the heat insulation structure of the pipe, the capacity of the heat exchanger, etc., it is preferably set to about 2 ° C. Yes.

JP 2008-71875 A JP 2009-254965 A

  By the way, in the substrate processing apparatus that performs freeze cleaning as described above, as a cooling gas for freezing the liquid film on the substrate, nitrogen gas that has been cooled to about −190 ° C. through a pipe passing through the liquid nitrogen, or the like. Is used. In order to introduce such a cooling gas into the chamber where the substrate is processed, a high-performance heat insulation facility is required, which increases the manufacturing cost of the apparatus. However, if the performance of the heat insulation equipment is lowered, the temperature of the cooling gas increases, and the time required for freezing the liquid film becomes longer.

  The present invention has been made in view of the above problems, and aims to suppress the cooling cost required for freezing the liquid film and shorten the time required for freezing the liquid film.

The invention according to claim 1 is a substrate processing apparatus for processing a substrate, wherein the chamber, a substrate holding portion for holding the substrate with the main surface facing upward in the chamber, and the main of the substrate. A liquid supply unit for supplying a supercooled liquid supercooled to a temperature lower than the freezing point on the surface, and rotating the substrate supplied with the supercooled liquid around an axis perpendicular to the main surface, A substrate rotation mechanism that forms a liquid film made of the supercooled liquid on a main surface, and a freezing unit that cools and freezes the liquid film.

  The invention according to claim 2 is the substrate processing apparatus according to claim 1, wherein the temperature of the main surface is adjusted by supplying the supercooling liquid from the liquid supply unit to the main surface of the substrate. After the temperature is lower than the freezing point of the supercooled liquid, the liquid film is formed by the substrate rotation mechanism.

  A third aspect of the present invention is the substrate processing apparatus according to the first or second aspect, wherein a cooling unit that cools the other main surface of the rotating substrate when the liquid film is formed. Further prepare.

  A fourth aspect of the present invention is the substrate processing apparatus according to the third aspect, wherein the cooling unit supplies the supercooled liquid to the other main surface.

  A fifth aspect of the present invention is the substrate processing apparatus according to any one of the first to fourth aspects, wherein the supercooling liquid is pure water.

  A sixth aspect of the present invention is the substrate processing apparatus according to any one of the first to fifth aspects, wherein a heated thawing liquid is supplied to the frozen film which is the frozen liquid film, and the frozen film is supplied. The apparatus further includes a frozen film removing unit that removes.

The invention according to claim 7 is a substrate processing method for processing a substrate, wherein a) a temperature lower than a freezing point on the main surface of the substrate held in a state where one main surface faces upward in the chamber. Supplying a supercooled liquid supercooled to b), and b) rotating the substrate about an axis perpendicular to the main surface to form a liquid film made of the supercooled liquid on the main surface. And c) a step of cooling and freezing the liquid film.

  In the present invention, the cooling cost required for freezing the liquid film can be suppressed. In addition, the time required for freezing the liquid film can be shortened.

It is a figure which shows the structure of the substrate processing apparatus which concerns on one embodiment. It is a figure which shows the flow of a process of a board | substrate.

  FIG. 1 is a diagram showing a configuration of a substrate processing apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the substrate processing apparatus 1 is a single-wafer type apparatus that processes semiconductor substrates 9 (hereinafter simply referred to as “substrates 9”) one by one. In the substrate processing apparatus 1, a freeze cleaning process is performed to remove particles and the like from the substrate 9 by forming a frozen film on the substrate 9 and removing the frozen film.

  The substrate processing apparatus 1 includes a substrate holding unit 2, a cup unit 21, a first liquid supply unit 31, a second liquid supply unit 32, a freezing unit 4, a substrate rotating mechanism 5, and a heating liquid supply unit 6. The chamber 7 and the control unit 8 are provided. The control unit 8 controls the configuration of the first liquid supply unit 31, the second liquid supply unit 32, the freezing unit 4, the substrate rotation mechanism 5, the heating liquid supply unit 6, and the like. The substrate holding unit 2 holds the substrate 9 in a state where one main surface 91 (hereinafter referred to as “upper surface 91”) of the substrate 9 is directed upward in the chamber 7. A circuit pattern or the like is formed on the upper surface 91 of the substrate 9. The cup unit 21 surrounds the substrate 9 and the substrate holding unit 2 in the chamber 7. The substrate rotating mechanism 5 rotates the substrate 9 together with the substrate holder 2 in a horizontal plane around a rotation axis that passes through the center of the substrate 9 and is perpendicular to the upper surface 91 of the substrate 9.

  The first liquid supply unit 31 supplies a supercooled liquid, which is a liquid supercooled to a temperature lower than the freezing point, to the upper surface 91 of the substrate 9. Supercooling refers to a state in which the state of a phase change of a substance does not change even at a temperature that should be changed or less. In the present embodiment, the supercooling is pure water that is supercooled from the first liquid supply unit 31 toward the center of the upper surface 91 of the substrate 9 to a temperature lower than 0 ° C. (for example, about −5 ° C.). Water is discharged. The same as the supercooled water supplied from the first liquid supply unit 31 toward the center of the other main surface 92 (hereinafter referred to as “lower surface 92”) of the substrate 9 from the second liquid supply unit 32. Supercooled liquid is discharged. As the supercooled liquid, it is preferable to use deionized water (DIW).

The freezing unit 4 supplies a cooling gas toward the upper surface 91 of the substrate 9. The cooling gas is a gas cooled to a temperature lower than the freezing point of the cooling liquid supplied from the first liquid supply unit 31. The freezing unit 4 includes a cooling gas nozzle 41 that discharges cooling gas, and a nozzle rotation mechanism 42 that rotates the cooling gas nozzle 41 horizontally around a rotation shaft 421. The nozzle rotation mechanism 42 includes an arm 422 that extends in the horizontal direction from the rotation shaft 421 and to which the cooling gas nozzle 41 is attached. As the cooling gas, cooled nitrogen (N ₂ ) gas is used. The temperature of the cooling gas is preferably −100 ° C. to −20 ° C., and in the present embodiment, it is about −50 ° C.

  The heating liquid supply unit 6 supplies a heating liquid, which is a heated liquid, to the central portion of the upper surface 91 of the substrate 9. In FIG. 1, for convenience of illustration, the heating liquid supply unit 6 is drawn above the first liquid supply unit 31, but in actuality, the first liquid supply unit 31 is retracted from above the substrate 9 to the outside. Thus, the heating liquid supply unit 6 moves upward from the outside of the substrate 9. Further, when the first liquid supply unit 31 is positioned above the substrate 9, the heating liquid supply unit 6 retreats from the upper side of the substrate 9 to the outside. As the heating liquid, pure water (preferably deionized water) heated to a temperature higher than room temperature is used. The temperature of the heating liquid is preferably 50 ° C. to 90 ° C., and about 80 ° C. in the present embodiment.

  FIG. 2 is a diagram illustrating a processing flow of the substrate 9 in the substrate processing apparatus 1. In the substrate processing apparatus 1, first, the substrate 9 is carried into the chamber 7 and held by the substrate holding unit 2, and the rotation of the substrate 9 by the substrate rotation mechanism 5 is started under the control of the control unit 8 (step S <b> 11). . The rotation speed of the board | substrate 9 is 300 rpm-900 rpm, for example, and is 400 rpm in this Embodiment.

  Subsequently, the first liquid supply unit 31 and the second liquid supply unit 32 are controlled by the control unit 8, and the supply of the supercooling liquid from the first liquid supply unit 31 to the upper surface 91 of the substrate 9 is started. Supply of the supercooling liquid from the unit 32 to the lower surface 92 of the substrate 9 is started (steps S12 and S13). The supercooling liquid supplied to the upper surface 91 and the lower surface 92 of the substrate 9 spreads over the entire surface of the upper surface 91 and the lower surface 92 from the central portion of the substrate 9 toward the outer edge portion by the rotation of the substrate 9, and Spatter from the outside. The supercooled liquid splashed from the substrate 9 is received by the cup portion 21 and collected.

  In the substrate processing apparatus 1, the supply of the supercooling liquid from the first liquid supply unit 31 and the second liquid supply unit 32 is continued for a predetermined time. Then, the substrate 9 is cooled until at least the temperature of the upper surface 91 of the substrate 9 becomes lower than 0 ° C. (that is, the freezing point of the supercooled liquid) (step S14). More preferably, the supply of the supercooling liquid to the upper surface 91 and the lower surface 92 of the substrate 9 is continued until the temperature of the entire substrate 9 becomes lower than 0 ° C. In the following description, the cooling of the substrate 9 in step S14 is referred to as “preliminary cooling”. In the present embodiment, the entire substrate 9 is cooled to about −1 ° C. by preliminary cooling.

  Thereafter, the number of rotations of the substrate 9 by the substrate rotation mechanism 5 decreases, and the number of rotations is changed to a value smaller than that at the time of preliminary cooling of the substrate 9 by the supercooling liquid. The rotation speed of the board | substrate 9 is 50 rpm-300 rpm, for example, and is 80 rpm in this Embodiment. Subsequently, the supply of the supercooling liquid from the first liquid supply unit 31 to the upper surface 91 of the substrate 9 is stopped (step S15). In the substrate processing apparatus 1, on the upper surface 91 of the substrate 9 that rotates at a low speed, a part of the supercooled liquid remaining on the upper surface 91 is scattered from the central portion of the substrate 9 toward the edge and from the substrate 9 to the outside. To do. Then, a thin liquid film of supercooled liquid is formed on the upper surface 91 of the substrate 9 (step S16). The thickness of the liquid film is approximately uniform over the entire upper surface 91 of the substrate 9 and is about 50 μm in the present embodiment. Note that the thickness of the liquid film is not necessarily uniform.

  In the substrate processing apparatus 1, even when a liquid film is formed on the upper surface 91 of the substrate 9, the second liquid supply unit 32 continuously supplies the supercooling liquid to the lower surface 92 of the rotating substrate 9, The lower surface 92 of the substrate 9 is cooled. In other words, the second liquid supply unit 32 is a cooling unit that cools the lower surface 92 of the substrate 9 even during the formation of the liquid film.

  When the formation of the liquid film is completed, the supply of the supercooled liquid from the second liquid supply unit 32 is stopped (step S17). Subsequently, the control of the control unit 8 starts the rotation of the cooling gas nozzle 41 by the nozzle rotation mechanism 42 of the freezing unit 4, and the cooling gas nozzle 41 repeats reciprocating movement between the center portion and the edge of the substrate 9. Then, a cooling gas is supplied from a cooling gas supply source provided outside the substrate processing apparatus 1 to the cooling gas nozzle 41 and supplied from the cooling gas nozzle 41 toward the upper surface 91 of the rotating substrate 9. Thereby, the cooling gas is supplied over the entire upper surface 91 of the substrate 9, and the liquid film on the upper surface 91 is cooled and frozen (step S18). Hereinafter, the frozen liquid film is also referred to as “frozen film”. In the substrate processing apparatus 1, the cooling gas is supplied from the cooling gas nozzle 41 stopped above the central portion of the substrate 9, and the cooling gas spreads from the central portion of the substrate 9 to the outer edge portion by the rotation of the substrate 9. Thus, a frozen film may be formed.

  On the substrate 9, the supercooled liquid that has entered between the substrate 9 and the particles and the like freezes (solidifies) and increases in volume, so that the particles and the like are lifted from the substrate 9 by a minute distance. As a result, the adhesion force between the particles and the substrate 9 is reduced, and the particles and the like are detached from the substrate 9. In addition, when the supercooled liquid freezes, particles or the like attached to the substrate 9 are peeled off from the substrate 9 by increasing the volume in a direction parallel to the upper surface 91 of the substrate 9.

  When the formation of the frozen film is completed, the supply of the cooling gas from the freezing unit 4 is stopped, and the cooling gas nozzle 41 moves from the upper side of the substrate 9 to the outside. Subsequently, the number of rotations of the substrate 9 by the substrate rotation mechanism 5 is increased, and the number of rotations is changed to a value larger than that at the time of forming the frozen film. The rotation speed of the board | substrate 9 is 1500 rpm-2500 rpm, for example, and is 2000 rpm in this Embodiment.

  Next, the heating liquid supply unit 6 is controlled by the control unit 8, and the heating liquid is supplied from the heating liquid supply unit 6 toward the upper surface 91 of the substrate 9. The heating liquid spreads over the entire upper surface 91 from the center of the substrate 9 toward the outer edge by the rotation of the substrate 9. As a result, the frozen film on the upper surface 91 is rapidly thawed (that is, liquefied) and scattered from the edge of the substrate 9 to the outside together with the heating liquid (step S19). Particles and the like adhering to the upper surface 91 of the substrate 9 are removed from the substrate 9 together with the liquid scattered from the substrate 9. The liquid scattered from the top of the substrate 9 to the outside is received by the cup portion 21 and collected. In the substrate processing apparatus 1, the heating liquid supply unit 6 serves as a frozen film removing unit that removes the frozen film by supplying a heating liquid that is a thawing liquid to the frozen film on the substrate 9.

  When the removal of the frozen film is completed, a rinsing liquid (for example, room-temperature deionized water) is supplied onto the upper surface 91 of the substrate 9 from a rinsing liquid supply unit (not shown), and the substrate 9 is rinsed (step S20). . The rotation speed of the substrate 9 during the rinsing process is preferably 300 rpm to 1000 rpm, and in this embodiment, 800 rpm. Thereafter, the rotational speed of the substrate 9 is changed to 1500 rpm to 3000 rpm (2000 rpm in the present embodiment), and a drying process for removing the rinse liquid on the substrate 9 is performed by the rotation of the substrate 9 (step S21). When the drying process of the substrate 9 is completed, the rotation of the substrate 9 by the substrate rotation mechanism 5 is stopped (step S22).

  As described above, in the substrate processing apparatus 1, a liquid film is formed on the upper surface 91 by the supercooled liquid supplied to the upper surface 91 of the substrate 9, and the liquid film is cooled by the cooling gas from the freezing unit 4. As a result, a frozen membrane is formed. The temperature of the liquid film formed by the supercooled liquid is lower than the freezing point of the liquid (pure water) and is in a state where freezing is likely to occur compared to pure water having a temperature higher than the freezing point. For this reason, when it is cooled by the freezing unit 4, the time required for freezing the liquid film (that is, the phase change time during which the liquid changes to a solid) can be shortened. Moreover, the removal rate of particles and the like can be improved by shortening the phase change time.

  In the substrate processing apparatus 1, the liquid film can be quickly frozen even when the temperature of the cooling gas from the freezing unit 4 is increased, compared to the case where the liquid film is formed with pure water having a temperature higher than the freezing point. For this reason, heat insulation equipment, such as piping which supplies cooling gas from a cooling gas supply source to cooling gas nozzle 41, can be simplified. As a result, the cooling cost required for freezing the liquid film by the freezing unit 4 can be suppressed. The phase change time becomes shorter as the supercooling width, which is the difference between the temperature of the supercooled liquid film and the freezing point, is larger.

  In the substrate processing apparatus 1, as described above, the supercooling liquid is supplied from the first liquid supply unit 31 and the second liquid supply unit 32 to the upper surface 91 and the lower surface 92 of the substrate 9, and the temperature of the substrate 9 is reduced to that of the supercooling liquid. After the temperature becomes lower than the freezing point, a liquid film is formed on the substrate 9. For this reason, it is suppressed that a liquid film absorbs the heat | fever of the board | substrate 9 and the temperature of a liquid film rises. As a result, the time required for freezing the liquid film can be further shortened. Moreover, the cooling cost required for freezing the liquid film can be further suppressed.

  In the substrate processing apparatus 1, when the liquid film is formed, the lower surface 92 of the substrate 9 is cooled by the second liquid supply unit 32, which is a cooling unit, and therefore the temperature of the substrate 9 and the liquid film rise during the liquid film formation. Is further suppressed. Thereby, the time required for freezing the liquid film can be further shortened. Moreover, the cooling cost required for freezing the liquid film can be further suppressed. As described above, the liquid supplied from the second liquid supply unit 32 to the lower surface 92 is the same liquid as the supercooled liquid supplied from the first liquid supply unit 31 to the upper surface 91. For this reason, the structure of the substrate processing apparatus 1 can be simplified, for example, by sharing a part of the piping of the first liquid supply unit 31 and the second liquid supply unit 32. Further, the liquids supplied to the upper surface 91 and the lower surface 92 of the substrate 9 can be collected together and reused in the processing of the substrate processing apparatus 1.

  As described above, since the frozen film on the substrate 9 is formed of pure water having a relatively large volume expansion coefficient, the adhesion force of particles or the like to the substrate 9 compared to the case where the frozen film is formed with another liquid. Can be further reduced. As a result, the removal rate of particles and the like from the substrate 9 can be improved. Further, by supplying the heating liquid and removing the frozen film from the substrate 9, particles and the like attached to the substrate 9 can be efficiently removed together with the frozen film. In the substrate processing apparatus 1, the heating liquid is a liquid similar to the supercooled liquid supplied from the first liquid supply unit 31 and the second liquid supply unit 32, so that the liquid splashes from the substrate 9 when the frozen film is thawed. Can also be recovered and reused.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, a liquid other than pure water (for example, hydrogen water, carbonated water, SC1 (ammonia hydrogen peroxide solution), tertiary butanol (TBA)) is supercooled from the first liquid supply unit 31 to the upper surface 91 of the substrate 9. A frozen film may be formed by supplying a supercooled liquid and freezing the liquid film of the supercooled liquid.

  In the freezing of the liquid film by the freezing unit 4, a cooling gas (for example, oxygen, air, ozone, argon) other than nitrogen having a temperature lower than the freezing point of the liquid forming the liquid film is supplied to the upper surface 91 of the substrate 9. May be performed. The freezing of the liquid film may be performed by supplying a cooling gas or liquid having a temperature lower than the freezing point of the liquid forming the liquid film to the lower surface 92 of the substrate 9.

  In the above embodiment, before the liquid film is formed on the upper surface 91 of the substrate 9 and when the liquid film is formed, the second liquid supply unit 32 that is a cooling unit is applied to the lower surface 92 of the substrate 9. The lower surface 92 is cooled by supplying a supercooled liquid of pure water, but the lower surface 92 may be cooled by supplying a supercooled liquid in which a liquid other than pure water is supercooled. . In addition, the lower surface 92 of the substrate 9 is cooled by a liquid that is not supercooled at a temperature lower than room temperature (more preferably, a liquid at a temperature lower than the freezing point of the liquid that forms a liquid film on the upper surface 91 of the substrate 9). May be performed by being supplied to the lower surface 92, or may be performed by supplying a gas having a temperature lower than room temperature. In the heating liquid supply unit 6, various liquids other than pure water may be heated to a temperature higher than room temperature as a thawing liquid and supplied to the upper surface 91 of the substrate 9. Also, a liquid at room temperature or lower may be used as the thawing liquid.

  In the substrate processing apparatus 1, the cooling of the lower surface 92 of the substrate 9 by the cooling unit may be omitted if the temperature rise of the liquid film during the liquid film formation is within an allowable range. If the temperature rise caused by the liquid film absorbing the heat of the substrate 9 is within an allowable range, the preliminary cooling of the substrate 9 in step S14 may be omitted. In this case, there is a possibility that the temperature of the liquid film when the freezing process by the freezing unit 4 is started becomes higher than the freezing point, but a liquid higher than the freezing point is supplied to the upper surface 91 of the substrate 9 to form a liquid film. Compared to the case, the time required for freezing the liquid film can be shortened, and the cooling cost required for freezing the liquid film by the freezing unit 4 can be suppressed.

  The substrate processed by the substrate processing apparatus 1 is a glass substrate for photomask, a glass substrate for liquid crystal display, a glass substrate for plasma display, a substrate for FED (Field Emission Display), a substrate for optical disk, a substrate for magnetic disk, a magneto-optical disk. It may be a substrate for use.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 2 Substrate holding part 4 Freezing part 5 Substrate rotating mechanism 6 Heating liquid supply part 7 Chamber 9 Substrate 31 First liquid supply part 32 Second liquid supply part 91 Upper surface 92 Lower surface S11-S22 Step

Claims (7)

A substrate processing apparatus for processing a substrate,
A chamber;
A substrate holding part for holding the substrate with the main surface facing upward in the chamber;
A liquid supply unit that supplies a supercooled liquid that is supercooled to a temperature lower than a freezing point on the main surface of the substrate;
A substrate rotating mechanism for forming a liquid film made of the supercooling liquid on the main surface by rotating the substrate supplied with the supercooling liquid around an axis perpendicular to the main surface;
A freezing part for cooling and freezing the liquid film;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 1,
By supplying the supercooling liquid from the liquid supply unit to the main surface of the substrate, the temperature of the main surface is set to a temperature lower than the freezing point of the supercooling liquid, and then the liquid film by the substrate rotating mechanism The substrate processing apparatus is formed. The substrate processing apparatus according to claim 1, wherein:
The substrate processing apparatus further comprising a cooling unit that cools the other main surface of the rotating substrate when the liquid film is formed. The substrate processing apparatus according to claim 3, wherein
The substrate processing apparatus, wherein the cooling unit supplies the supercooled liquid to the other main surface. The substrate processing apparatus according to claim 1, wherein:
The substrate processing apparatus, wherein the supercooling liquid is pure water. A substrate processing apparatus according to any one of claims 1 to 5,
A substrate processing apparatus, further comprising: a frozen film removing unit that supplies a heated thawing liquid to a frozen film that is the frozen liquid film and removes the frozen film. A substrate processing method for processing a substrate, comprising:
a) supplying a supercooled liquid subcooled to a temperature lower than the freezing point to the main surface of the substrate held in a state where one main surface faces upward in the chamber;
b) forming a liquid film composed of the supercooled liquid on the main surface by rotating the substrate about an axis perpendicular to the main surface;
c) cooling and freezing the liquid film;
A substrate processing method comprising:

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