JP2006122784A - Substrate washing method and substrate washing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate washing method capable of continuously performing the peeling and removal of the pollutant on a substrate from the surface of the substrate and the extrusion of the pollutant to the outside of the substrate using only pure water but not using a chemical liquid of a high concentration without using a plurality of chemical liquid tanks, pin water discharge devices and the like, and a substrate washing apparatus. <P>SOLUTION: The substrate 1 is held to an inclined posture so as to form angle θ1 of inclination with respect to a horizontal surface 2 and pure water in a pressurized state is ejected to the surface 1a to be washed of the substrate 1 from a pure water jet means 3 so as to leave an interval d1 from the surface 1a to be washed to form a liquid film 7 flowing on the surface 1a to be washed in one direction from the upper part to the lower part of the substrate 1 to remove the pollutant on the surface 1a to be washed of the substrate 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate cleaning method and a cleaning apparatus.

  Currently, when manufacturing an electronic device using a semiconductor substrate or the like, the substrate contamination that adheres to the surface of the semiconductor substrate (hereinafter simply referred to as “substrate”) tends to cause malfunction of the electronic device. In addition, it is essential to remove substrate contaminants attached to the surface. Examples of substrate contaminants include fine particles (particles), metal particles, metal compounds, and organic substances. In addition, a wide variety of cleaning methods have been developed and put into practical use in the electronic device manufacturing process, but cleaning using chemicals (hereinafter referred to as “chemical cleaning”) is generally used to remove substrate contaminants as described above. Is. In chemical cleaning, a substrate is immersed in a chemical solution and the substrate contamination on the substrate surface is removed by utilizing a chemical reaction between the active ingredient contained in the chemical solution and the substrate contamination on the substrate surface. As an example, an RCA cleaning method may be used.

  However, as described above, there are several kinds of substrate contaminants, and their chemical reactivity is different. Therefore, it is difficult to remove all substrate contaminants with a single chemical cleaning. Therefore, under the present circumstances, the chemical solution is washed multiple times by changing the chemical solution. In that case, it is necessary to use a plurality of chemical tanks or to replace the chemical liquid in the chemical tank for each cleaning. However, when a plurality of chemical tanks are used, there arises a problem that the cleaning equipment is enlarged and complicated. In addition, since the chemical tank itself needs to be cleaned in order to replace the chemical liquid, there is a problem that the operation becomes complicated and it takes a long time to replace the chemical liquid and clean the chemical tank. In addition, chemicals contain high concentrations of chemical substances that have a large environmental impact, such as ammonium hydroxide, hydrogen peroxide, hydrochloric acid, sulfuric acid, hydrogen fluoride, and ammonium fluoride. Since the amount is also large, equipment for processing used chemicals is required.

  In view of such a current situation, for example, an ultrasonic cleaning means for performing ultrasonic cleaning by applying ultrasonic waves to the liquid while discharging the liquid toward the substrate, and the ultrasonic cleaning means are provided at different positions, High-pressure cleaning means for jetting high-pressure liquid toward the area where the liquid to which ultrasonic waves are applied is present on the substrate, and is discharged from the ultrasonic cleaning means onto the surface to be cleaned and flows along the surface to be cleaned. A substrate cleaning apparatus has been proposed in which a high-pressure cleaning means jets a high-pressure liquid toward an ultrasonically applied liquid, and the ultrasonic cleaning and high-pressure cleaning are performed in combination (for example, a patent) Reference 1). Ultrapure water is used for both the liquid discharged from the ultrasonic cleaning means and the liquid ejected from the high pressure cleaning means. The substrate cleaning apparatus of Patent Document 1 removes fine particles having a relatively large particle size from among fine particles adhering to the substrate surface by using pure water to which physical energy such as ultrasonic waves and pressure is applied without using a chemical solution. Is. However, the area where fine particles on the substrate surface are removed by this substrate cleaning apparatus is mainly limited to a narrow area of “dot” shape or “line” shape where ultrasonic waves act, and all fine particles on the substrate surface Cannot be removed almost completely. Therefore, in order to improve the removal efficiency of fine particles, a plurality of extra devices such as a device that separates fine particles in a region where ultrasonic waves do not act from the substrate surface, a device that discharges fine particles separated from the substrate surface to the outside of the substrate surface, etc. Is required. Furthermore, the substrate cleaning apparatus of Patent Document 1 removes only particles having a relatively large particle size adhering to the substrate surface, and other substrates such as fine particles, metal particles, metal compounds, and organic substances having a small particle size. It does not remove contaminants sufficiently. Therefore, in order to remove substrate contaminants other than particles having a large particle size, it is necessary to carry out chemical cleaning a plurality of times in the same manner as in the past, and the conventional problems have not been solved.

  Another type of substrate cleaning apparatus that cleans a substrate using pure water has been proposed (see, for example, Patent Document 2). FIG. 13 is a side view schematically showing the configuration of the substrate cleaning apparatus 100. FIG. 14 is a side view seen from the direction of arrow 103 for explaining the transport posture of the substrate W in the substrate cleaning apparatus 100. The substrate cleaning apparatus 100 is mainly intended for cleaning a large substrate that is required in accordance with an increase in size of a liquid crystal display, a plasma display, and the like, and the substrate W is placed in a direction indicated by an arrow 103 in the cleaning tank 101. A cleaning roller 104, 105, 106, 107, and 108 for cleaning the substrate W by spraying pure water onto the substrate W; A water flow injection unit 109, 110, 111, 112, 113 that injects a curtain-like water flow to the substrate W from above so as to cross the conveyance path. The cleaning unit 104 is provided on the lower surface side of the substrate W, and includes a cleaning brush 114 that brush-cleans the substrate W, and discharge units 115, 116, and 117 that eject low-pressure pure water. The cleaning unit 105 includes discharge units 118 and 119 that inject low-pressure pure water. The cleaning unit 106 includes discharge units 120 and 121 that inject high-pressure pure water. The cleaning unit 107 includes a discharge unit 122 that jets a mixed fluid of pure water and air (gas), and a discharge unit 123 that jets high-pressure pure water. The cleaning unit 108 includes discharge units 124 and 125 that inject pure water. As shown in FIG. 14, in the substrate cleaning apparatus 100, the substrate W is placed on the transport roller 102 in an inclined posture in which one end with respect to the horizontal line 130 has a larger separation distance than the other end. It is conveyed in the conveying direction of an arrow 103 that is perpendicular to the paper surface of FIG.

  According to the substrate cleaning apparatus 100, in order to place the substrate W on the transport roller 102 and transport it in the direction of the arrow 103 to perform multi-stage cleaning, the water jets 109, 110, 111, and 112 are disposed in the transport path. 113 and cleaning units 104, 105, 106, 107, and 108 are alternately provided, a non-pressurized or pressurized pure water stream is sprayed onto the substrate W, and particulates are removed using physical energy. In the substrate cleaning apparatus 100, the physical energy added to the fine particles is increased by increasing the injection amount of pure water that is a cleaning liquid and the flow rate of pure water on the surface of the substrate W in order to improve the fine particle removal performance. Try to. However, when the flow rate is increased on the surface of the substrate W, a thick pure water liquid film is formed, and this pure water liquid film often inhibits physical energy from being applied to the fine particles on the surface of the substrate W. Therefore, even if the substrate cleaning apparatus 100 is used, it is difficult to obtain a sufficient particle removal effect. In addition, in the substrate cleaning apparatus 100, not only the substrate W but also the discharge units 120 and 121 that eject high-pressure pure water are arranged in an inclined posture so as to be parallel to the substrate W. For this reason, since the pressurized pure water stream sprayed from the discharge units 120 and 121 is sprayed substantially perpendicularly to the surface of the substrate W, the above-described thick pure water liquid film is generated. And its thickness tends to be even greater. Furthermore, since each of the discharge units 120 and 121 has a plurality of discharge holes, it is difficult for one-way flow of pure water constituting the liquid film on the surface of the substrate W to occur, and the liquid flow discharged from each discharge unit Retention on the surface of the substrate W due to collision between each other easily occurs. In that case, re-adhesion of fine particles once peeled off to the substrate W often occurs.

Japanese Patent No. 3323384 Japanese Patent Laid-Open No. 2004-74021

  An object of the present invention is to use fine water, fine powder, metal powder, metal compound, organic matter, and the like, which are substrate contaminants adhering to the substrate surface, using only pure water instead of high-concentration chemical liquid, and a plurality of chemical liquid tanks and pure water discharge devices It is an object to provide a substrate cleaning method and a substrate cleaning apparatus that can continuously remove and remove substrate contaminants from and from the substrate surface without using the substrate.

  The present invention sprays pure water under pressure from a pure water injection position spaced from the surface to be cleaned onto a surface to be cleaned placed at an angle with respect to a horizontal plane, The substrate cleaning method is characterized in that a liquid film that is a one-way flow from the upper part to the lower part on the surface to be cleaned is generated to remove substrate contaminants on the surface to be cleaned.

  The substrate cleaning method of the present invention is characterized in that the substrate contamination is one or more selected from fine particles, metal particles, metal compounds and organic substances.

  Furthermore, the substrate cleaning method of the present invention is characterized in that the angle formed by the substrate with respect to the horizontal plane is not less than 5 degrees and not more than 90 degrees.

  Furthermore, the substrate cleaning method of the present invention is characterized in that the thickness of the liquid film is less than 1 mm.

  Furthermore, the substrate cleaning method of the present invention is characterized in that the distance between the surface to be cleaned of the substrate and the pure water injection position is 1 mm or more and 50 mm or less.

Further, the present invention generates a liquid film that is a unidirectional flow from the upper part to the lower part on the surface to be cleaned on the surface to be cleaned on the surface to be cleaned placed at an angle with respect to the horizontal plane. A substrate cleaning apparatus for removing substrate contaminants adhering to the surface to be cleaned of the substrate,
Substrate holding means for holding the substrate in a posture that makes an angle with respect to a horizontal plane;
Substrate cleaning characterized by comprising pure water spraying means for spraying pure water in a pressurized state onto the surface to be cleaned, which is provided at an interval with respect to the surface to be cleaned held by the substrate holding means Device.

  Furthermore, the substrate cleaning apparatus of the present invention is a nozzle in which the pure water injection means has a plurality of pure water injection holes having a diameter of 200 μm or less, and the pure water injection holes are arranged in a straight line. It is characterized by being.

  Furthermore, the substrate cleaning apparatus of the present invention is characterized in that the pure water injection means is a slit nozzle having an opening gap of 200 μm or less.

  Further, the substrate cleaning apparatus of the present invention is characterized in that it includes a moving means for moving the pure water jetting means up and down along the surface to be cleaned of the substrate.

  According to the present invention, pure water is jetted onto the surface to be cleaned, which is held in an inclined posture so as to form a constant inclination angle with respect to the horizontal plane, at a distance from the surface to be cleaned. On the cleaning surface, it is possible to generate a unidirectional flow from the upper part to the lower part of pure water constituting the liquid film. As a result, substrate contaminants adhering to the substrate surface, such as fine particles, metal particles, metal compounds, and organic substances, can be completely removed. In addition, the substrate contaminants peeled and removed from the substrate surface are immediately removed from the substrate after the removal and removal by pure water flowing in one direction, so that they do not reattach to the substrate surface.

  The substrate cleaning method of the present invention has a strong cleaning power, and does not use several kinds of chemicals as in the prior art, but only pure water, and not only fine particles but also metal particles, metal compounds, organic substances, etc. Can be removed. Therefore, it does not require a plurality of medicine tanks and facilities for processing the medicine after use, and does not require complicated operations such as replacement of medicines in a single medicine tank. Further, it is not necessary to perform multi-stage cleaning using a plurality of pure water discharge devices. Furthermore, the substrate cleaning method of the present invention does not require any special equipment and can be carried out if there is a substrate holding means for holding the substrate in an inclined posture and a pure water injection means for high-pressure injection of pure water onto the substrate. It has the advantage that it can be implemented with simple equipment.

  In the present specification, the fine particles mean organic or inorganic dust generally called particles and having a particle size of 10 μm or less. A metal particle means the fine particle which is a lump containing metal atoms, such as a heavy metal and a noble metal, its ion, etc., for example. The metal compound means an oxide film, a natural oxide film, an oxide, etc. remaining on the substrate surface. The organic substance means wax, oil, resin, photoresist piece and the like.

  Further, according to the present invention, in the substrate cleaning method of the present invention, the liquid film on the surface to be cleaned is removed when the inclined substrate is in the range of 5 to 90 ° with respect to the horizontal plane. The flow of pure water constituting the unidirectional flow from the upper part to the lower part is further stabilized, and the substrate contaminant removal efficiency is improved.

  According to the invention, in the substrate cleaning method of the invention, the angle formed by the substrate with respect to the horizontal plane, the injection pressure and the injection amount of pure water, and the pure water with respect to the substrate so that the thickness of the liquid film is less than 1 mm. By appropriately selecting the injection angle and the like, the substrate contaminant removal efficiency is further improved.

  Further, according to the present invention, in the substrate cleaning method of the present invention, the liquid film 7 on the surface to be cleaned is adjusted by adjusting the distance between the surface to be cleaned and the pure water injection position in the range of 1 to 50 mm. It is easy to generate a one-way flow from the upper part to the lower part of the pure water constituting the substrate, and the substrate contaminants can be stably removed with good reproducibility.

  Moreover, according to this invention, the board | substrate cleaning apparatus for enforcing the board | substrate cleaning method of this invention is provided. The substrate cleaning apparatus requires only two means: a substrate holding means for holding the substrate in an inclined posture and a pure water injection means provided at a distance from the surface to be cleaned of the substrate. Compared to a substrate cleaning device, it has a very simple structure, not only the performance of removing substrate contaminants, but also the amount of pure water used, recoverability of sewage after cleaning, operability, running cost, manufacturing cost, etc. Highly superior in terms. That is, the amount of pure water used is small, the sewage can be almost completely recovered, the operation is simple, and the running cost and the cost for manufacturing the apparatus are low.

  Further, according to the present invention, in the substrate cleaning apparatus of the present invention, a nozzle or an opening gap of 200 μm formed as a plurality of pure water injection holes having a diameter of 200 μm or less is arranged as a pure water injection unit. By using the following slit nozzle, it is possible to easily generate a unidirectional flow from the upper part to the lower part of the pure water constituting the liquid film on the surface to be cleaned of the substrate, thereby increasing the substrate contamination removal efficiency. .

  Further, according to the present invention, in the substrate cleaning apparatus of the present invention, by providing the moving means for moving the pure water jetting means up and down along the surface to be cleaned of the substrate, a general substrate can be used especially for cleaning a large substrate. The removal efficiency equivalent to the removal efficiency of the substrate contaminants in the cleaning is obtained.

  FIG. 1 is a side view for explaining the substrate cleaning method of the present invention. FIG. 2 is a perspective view for explaining the substrate cleaning method of the present invention. The substrate 1 is held in an inclined posture at an inclination angle θ1 with respect to the horizontal plane 2 by a substrate holding means (not shown). Here, the inclination angle θ1 of the substrate 1 is preferably 5 to 90 °, more preferably 75 to 90 °. If the angle is less than 5 ° or exceeds 90 °, a unidirectional flow from the upper part to the lower part of the pure water constituting the liquid film 7 is not sufficiently generated on the surface to be cleaned 1 of the substrate 1, and substrate contamination Removal may be insufficient.

  The pure water injection means 3 is provided facing the surface 1a to be cleaned of the substrate 1 and with a gap d1. The pure water injection means 3 has a pressure-resistant structure (not shown) in its interior, and pure water in a state of being pressurized against the surface to be cleaned 1 a of the substrate 1 (hereinafter referred to as “pressurized pure water”). ), And a pressure-resistant pipe 6 for supplying pressurized pure water to the pressure-resistant nozzle 4, and a pure water pressure supply means (not shown).

Note that it is desirable that the alignment direction of the surface to be cleaned 1a and the injection holes 5 is substantially parallel.
Here, when the alignment direction of the to-be-cleaned surface 1a and the injection hole 5 is substantially parallel, the space | interval d1 is the length of the perpendicular to the to-be-cleaned surface 1a from the injection hole 5, Preferably it is 1-50 mm, More preferably, it is 1-10 mm. If the thickness is less than 1 mm or exceeds 50 mm, the surface 1 to be cleaned of the substrate 1 does not sufficiently generate a unidirectional flow from the upper part to the lower part of the pure water constituting the liquid film 7, thereby removing substrate contaminants. May be insufficient.

  The pure water ejected from the pure water ejecting means 3 preferably has a specific resistance value of 10 MΩcm or more, and particularly preferably 18 MΩcm or more (that is, ultrapure water). Moreover, the pure water can contain the active ingredient of the conventional chemical | medical solution for board | substrate cleanings, such as hydrogen and ammonia, in the range which does not impair the preferable advantage of the board | substrate cleaning method of this invention.

  As the pressure-resistant nozzle 4, a pressure-resistant nozzle that is a circular injection hole 5 having a diameter of 200 μm or more and in which a plurality of injection holes 5 are arranged in a line on a straight line can be used. A pressure-resistant slit nozzle in which the injection holes 5 are formed in a slit shape and the slit opening gap is 200 μm or less can also be used. The pressure-resistant piping 6 is made of a material having pressure resistance and flexibility, and is provided so as to be movable up and down and left and right. The deionized water pressure supply means (not shown) includes, for example, a deionized water storage tank that stores deionized water produced by a deionized water production apparatus, and a pressure supply pipe 6 that supplies the deionized water in the deionized water storage tank while pressurizing the deionized water. And a pressure pump.

  The pure water injection means 3 is supported by a moving means (not shown) so as to be movable up and down along the surface to be cleaned 1a while maintaining the distance d1. In the substrate cleaning method of the present invention, the high pressure region 16 shown in FIG. 6 is present in the liquid flow 7 in the vicinity of the point where the pure water jetted from the pure water jetting means 3 reaches the surface 1a to be cleaned of the substrate 1. appear. The liquid film region 8 below the lower end of the high pressure region 16 (hereinafter referred to as “cleaning execution region 8”) is a region having particularly high cleaning power. By moving the pure water injection means 3 up and down, preferably from the upper part to the lower part, the cleaning execution region 8 can be moved on the surface to be cleaned 1a. Can be washed.

  In order to perform substrate cleaning efficiently, the cleaning execution region 8 is preferably at least 0 to 5 cm, more preferably 0 to 10 cm from the lower end of the high-pressure region 16. For this purpose, various conditions such as the inclination angle θ1 of the substrate 1, the specific resistance value of pure water used as the cleaning liquid, and the jet pressure of pure water onto the surface to be cleaned 1a may be appropriately changed.

  Further, when the pure water ejected from the pure water ejecting means 3 reaches the surface to be cleaned 1a while maintaining a linear trajectory instead of a parabolic shape, an angle θ2 formed by the pure water trajectory and the substrate 1 is formed. Is preferably an acute angle. As a result, when the injected pure water collides with the surface to be cleaned 1a, the thickness of the liquid film 7 formed on the surface to be cleaned 1a is reduced, and the liquid film with a small film thickness that is effective for removing substrate contaminants. 7 is easily formed, and it becomes easier to generate a one-way flow from the upper part to the lower part of the pure water constituting the liquid film 7 on the surface to be cleaned 1a. The thickness of the liquid film 7 will be described later.

  As shown in FIGS. 1 and 2, the surface to be cleaned 1a held in an inclined posture so as to form an angle θ1 with respect to the horizontal plane 2 is spaced from the surface to be cleaned 1a by a distance d1. When ultrapure water is injected from the injection hole 5 of the pressure-resistant nozzle 4 of the pure water injection means 3 disposed, a liquid film 7 is generated on the surface to be cleaned 1a, and the pure water constituting the liquid film 7 is Then, the surface to be cleaned 1a flows in one direction from the top to the bottom, and flows over the surface to be cleaned 1a to peel and remove substrate contaminants (not shown) adhering to the surface to be cleaned 1a.

  FIG. 3 is a cross-sectional view schematically showing the state of the liquid film flow in the cleaning execution region 8. FIG. 4 is a cross-sectional view schematically showing a mechanism for removing fine particles in the cleaning execution region 8. Note that ultrapure water is preferably used as pure water for removing fine particles, and FIG. 4 relates to the removal of fine particles. Therefore, in the description of FIGS. 3 and 4, ultrapure water is used as pure water. Hereinafter, in the same manner, in the explanation regarding the removal of the fine particles, ultrapure water is used.

  In FIG. 3, an arrow means a liquid flow in the liquid film 7 and a length of the arrow means a flow velocity of the liquid flow. The longer the arrow, the higher the flow velocity. Further, the cleaning execution area 8 is further divided into four first to fourth small areas 9, 10, 11 and 12, and a gap having an equal length with respect to the liquid film surface 7a is provided between the small areas. Provide. Further, in the four first to fourth small regions 9, 10, 11, and 12, the lines connecting the vertices of the arrows indicating the liquid flow are defined as first to fourth flow velocity lines 9x, 10x, 11x, and 12x.

  In the cleaning execution region 8, in the first small region 9 that is located immediately below the point where the ultrapure water ejected from the pure water ejecting means 3 arrives, the liquid flow 9 a near the surface to be cleaned 1 a and the thickness direction of the liquid film 7 The liquid flows 9b, 9c, 9d in the central portion of the liquid and the liquid flow 9e near the liquid film surface 7a all have substantially the same flow velocity, and a substantially linear flow velocity line 9x is obtained. Although the liquid flows 9a to 9e flow downward as they are, they receive a shearing force from the surface to be cleaned 1a due to the viscosity of ultrapure water, and the flow velocity is reduced as the surface is closer to the surface to be cleaned 1a. Therefore, in the second small region 10 assumed downstream of the first small region 9 in the liquid film flow direction, the liquid flow 10a flowing near the surface to be cleaned 1a is decelerated, and the liquid flow 10b is slightly increased. Will be slowed down. On the other hand, the other liquid flows 10c, 10d, and 10e located at positions relatively separated from the surface to be cleaned 1a are hardly decelerated, and the second flow velocity line 10x has a parabolic shape.

  Further, in the third small region 11, the tendency of the liquid flow to decelerate due to the shearing force in the vicinity of the surface to be cleaned 1a becomes more prominent, and the liquid flow 11a closest to the surface to be cleaned 1a The liquid flows 11b to 11d are also decelerated according to the distance from the surface to be cleaned 1a, and only the liquid flow 11e in the vicinity of the liquid flow surface 7a is not decelerated. As a result, the third flow velocity line 11x has a parabolic shape with a larger curvature at the curved portion than the second flow velocity line 10x, and a large difference in the flow velocity of the liquid flow may occur depending on the position in the thickness direction of the liquid film 7. I understand.

  In the fourth small region 12 assumed at the lowermost part in the cleaning execution region 8, the liquid flow 12 a closest to the surface to be cleaned 1 a is further decelerated and becomes almost “0”. Although the liquid flows 12b to 12d are also decelerated, the liquid flow 12e flowing through the position farthest away from the surface to be cleaned 1a is hardly decelerated. The obtained fourth flow velocity line 12x has a parabolic shape with a larger curvature, but in the cleaning execution region 8, the liquid flow in the vicinity of the liquid film surface 7a is almost subjected to shearing force due to contact with the surface to be cleaned 1a. And keep approximately the same flow rate. This liquid flow in the vicinity of the liquid film surface 7a is very effective in preventing re-adhesion of substrate contaminants (not shown) that peel off from the surface to be cleaned 1a.

  Of the first to fourth flow velocity lines 9x to 12x obtained in the first to fourth small regions 9 to 12, the liquid flow having the first to third flow velocity lines 9x to 11x adheres to the surface to be cleaned 1a. It is particularly effective for removing contaminants. That is, as shown in FIG. 4, the fine particles 13a adhering to the surface to be cleaned 1a are separated from the surface to be cleaned 1a due to the stress 14 caused by the liquid flows 9a and 9b in the vicinity of the surface to be cleaned 1a, and floated. The fine particles 13b flow around the cleaning surface 1a. The fine particles 13b are further subjected to the stresses of the liquid flows 9b to 9e, particularly the liquid flow 9e, and further float in the liquid film 7 toward the liquid film surface 7a, and become fine particles 13c that flow around the liquid film surface 7a. It is discharged outside the substrate 1.

  Next, in removing the fine particles from the surface to be cleaned 1a of the substrate 1 in the substrate cleaning method of the present invention, the influence of the thickness of the liquid film generated when the ultrapure water is sprayed on the surface to be cleaned 1a on the removal of the fine particles. Will be described with reference to FIGS. FIG. 5 is a cross-sectional view schematically showing the state of the liquid film 15 generated on the surface to be cleaned 1a of the substrate 1 placed on a horizontal plane. FIG. 6 is a cross-sectional view schematically showing the state of the liquid film 7 generated on the surface to be cleaned 1a of the substrate 1 in the substrate cleaning method of the present invention.

  In FIG. 5, the board | substrate 1 is mounted in the horizontal surface which is not shown in figure. When the pressurized ultra-pure water is jetted from the pressure-resistant nozzle 4 of the pure water jetting means arranged at a distance above the surface to be cleaned 1a with respect to the surface to be cleaned 1a of the substrate 1, the surface to be cleaned 1a becomes Since it is horizontal, ultrapure water stays on the surface to be cleaned 1a, and a liquid film 15 having a large film thickness is formed. Although the thickness t1 of the liquid film 15 varies depending on the injection amount, injection pressure, and the like of the ultrapure water, when the ultrapure water is jetted from the pressure-resistant nozzle 4 toward the surface to be cleaned 1a in a linear locus, Grows to 1 mm or more. Further, at and near the point where the ultrapure water reaches the surface to be cleaned 1a, the high pressure region 16 in which the high pressure added to the ultrapure water is maintained almost simultaneously with the arrival of the ultrapure water. Is formed. Since the ultrapure water sprayed thereafter flows so as to bypass the high pressure region 16, the ultrapure water does not reach the surface 1a to be cleaned of the substrate 1 and is near the liquid film surface 15a. A flow (main flow) 17 is generated. As a result, the flow rate of ultrapure water in the vicinity of the surface to be cleaned 1a is substantially “0”, and even if fine particles not shown adhere to the surface to be cleaned 1a, it is difficult to remove from the surface to be cleaned 1a.

  On the other hand, as shown in FIG. 6, in the substrate cleaning method of the present invention, the substrate 1 is held at an angle θ <b> 1 with respect to the horizontal plane 2. As a result, when ultrapure water is discharged onto the surface to be cleaned 1a of the substrate 1, the ultrapure water does not stay on the surface to be cleaned 1a, but is discharged under the substrate 1 mainly under the action of gravity. . For this reason, the thickness t2 of the liquid film 7 formed on the surface 1a to be cleaned of the substrate 1 is significantly thinner than 1 mm. Specifically, the thickness is about 100 to 500 μm. Further, as in the case where the substrate 1 is placed on the horizontal surface 2, in this case as well, there is a high-pressure region at a point where the ultrapure water sprayed from the pressure-resistant nozzle 4 reaches the surface to be cleaned 1 a of the substrate 1 and in the vicinity thereof. 16 is formed. However, since the substrate 1 is tilted and held with respect to the horizontal plane 2, the high-pressure region 16 is relatively small compared to the case of FIG. Accordingly, after the high pressure region 16 is formed, the ultrapure water sprayed toward the surface to be cleaned 1a does not obstruct the high pressure region 16 and does not bypass the high pressure region. A main flow 17 that flows in the vicinity and flows in the vicinity of the surface to be cleaned 1a is generated. Therefore, fine particles (not shown) adhering to the surface to be cleaned 1 a are removed by the main flow 17. Here, since the liquid film thickness t2 mainly depends on the inclination angle θ1 of the substrate 1 with respect to the horizontal plane 2, in order to further improve the effect of removing fine particles adhering to the surface to be cleaned 1a, the inclination angle θ1 is set to 90 °. It is preferable to approach. The closer the inclination angle θ1 is to 90 °, the smaller the liquid film thickness t2 and the fine particles are more likely to be subjected to stress due to the main flow 17. In addition, since the liquid film thickness t2 is extremely small, the main flow 17 is shown as one liquid flow for convenience in FIG. 6, but actually, as shown in FIG. 3, FIG. 4 and FIGS. Divided into liquid streams.

  Next, the case where the substrate contaminant adhering to the surface to be cleaned 1a of the substrate 1 is metal particles will be described with reference to FIGS. FIG. 7 is a cross-sectional view schematically showing a mechanism for removing the metal particles 18 a in the cleaning execution region 8 of the surface 1 a to be cleaned of the substrate 1. In addition, since the subcritical ultrapure water pressurized to the subcritical state is particularly preferable among the pure water for removing the metal particles, the subcritical ultrapure water is used in the description regarding FIG. When subcritical ultrapure water pressurized in the pressure-resistant nozzle 4 is sprayed onto the surface to be cleaned 1a of the substrate 1 held in an inclined posture so as to form an inclination angle θ1 with respect to the horizontal plane 2, the cleaning execution region 8 In the first small region 9 which is the uppermost portion, liquid flows 9a, 9b, 9c, 9d and 9e are generated in the liquid film 7. Although these liquid flows are expressed as five flows for convenience, these liquid flows can be combined and expressed as one liquid flow (main flow), or can be subdivided into six or more liquid flows. Is possible. When the metal particles 18a adhering to the surface to be cleaned 1a are subjected to stress due to the liquid flows 9a and 9b flowing through the vicinity of the surface to be cleaned 1a, the bonds 19 between the metal atoms constituting the metal particles 18a are partially formed. It is cut and eluted into the liquid film 7 as metal particles 18b. The metal particles 18b are further subjected to stress such as the liquid flows 9c, 9d, and 9e, and flow in the liquid film 7 from the central portion in the thickness direction of the liquid film 7 to the liquid film surface 7a like the metal particles 18c. And discharged below the substrate 1. At this time, since most of the metal particles 17c do not flow through the vicinity of the surface to be cleaned 1a, reattachment to the surface to be cleaned 1a is prevented. Thus, in order to remove the metal particles 18a adhering to the surface to be cleaned 1a of the substrate 1, a liquid flow of subcritical ultrapure water that flows in the vicinity of the surface to be cleaned 1a is required. Further, when the thickness of the liquid film 7 is reduced, the liquid flow of subcritical ultrapure water flows through the vicinity of the surface to be cleaned 1a, and the removal performance of the metal particles 18a is improved. In order to reduce the thickness of the liquid film 7, it is preferable to make the inclination angle θ1 of the substrate 1 with respect to the horizontal plane 2 close to 90 °, as described in the explanation with reference to FIG.

  Next, the case where the substrate contaminant adhering to the surface to be cleaned 1a of the substrate 1 is a metal compound will be described with reference to FIGS. FIG. 8 is a cross-sectional view schematically showing a mechanism for removing the metal compound in the cleaning execution region 8 of the surface to be cleaned 1 a of the substrate 1. For the removal of the metal compound, subcritical ultrapure water is preferable as in the case of the metal particles. Therefore, subcritical ultrapure water is also used in the description related to FIG. Even when the metal compound adhering to the surface to be cleaned 1a of the substrate 1 is removed, a liquid flow of subcritical ultrapure water that flows near the surface to be cleaned 1a is required. That is, when subcritical ultrapure water pressurized in the pressure-resistant nozzle 4 is sprayed onto the surface to be cleaned 1 a of the substrate 1 that is tilted and held so as to form the tilt angle θ 1 with respect to the horizontal plane 2, Liquid flows 9a, 9b, 9c, 9d, and 9e are generated. In the same manner as shown in FIG. 7, the metal compound 20a adhering to the surface to be cleaned 1a is cut in the bond 21 between the metal compounds 20a and eluted into the liquid film 7 as the metal compound 20b. It flows through the liquid film 7 from the central part in the thickness direction to the liquid film surface 7 a and is discharged below the substrate 1. Further, it is preferable to reduce the thickness of the liquid film 7 as in the case of the removal of the metal particles 18a shown in FIG. 7, and for this purpose, the inclination angle θ1 of the substrate 1 with respect to the horizontal plane 2 is also set to 90 °. It is better to approach.

  Next, the case where the substrate contaminant that adheres to the surface to be cleaned 1a of the substrate 1 is an organic material will be described with reference to FIGS. FIG. 9 is a cross-sectional view schematically showing a mechanism for removing the organic matter 22a in the cleaning execution region 8 of the surface 1a to be cleaned of the substrate 1. FIG. For the removal of the organic matter 22a, subcritical ultrapure water is preferable as in the case of the removal of the metal particles 18a and the metal compound 20a. Therefore, subcritical ultrapure water is also used in the description related to FIG. The organic matter 22a is removed in the same manner as the metal particles 18a shown in FIG. 7 and the metal compound 20a shown in FIG. That is, when pressurized subcritical ultrapure water is sprayed from the pressure-resistant nozzle 4 onto the surface to be cleaned 1a of the substrate 1 held at an angle θ1, the liquid film 7 of subcritical ultrapure water is applied onto the surface to be cleaned 1a. And the liquid flows 9a, 9b, 9c, 9d and 9e are generated in the liquid film 7. Among these, the liquid flows 9a and 9b flowing especially near the surface to be cleaned 1a give stress to the organic matter 22a adhering to the surface to be cleaned 1a. As a result, the carbon bond 23 in the organic substance 22 a is cut, and the organic substance 22 b that is an organic substance piece is eluted in the liquid film 7. The organic matter 22b is further subjected to stress such as the liquid flow 9c, 9d, 9e, and becomes the organic matter 22c that flows through the central portion of the liquid film 7 in the thickness direction. The organic matter 22c is finally discharged below the substrate 1. In order to increase the removal efficiency of the organic matter 22a, it is effective to reduce the thickness of the liquid film 7 by making the inclination angle θ1 of the substrate 1 with respect to the horizontal plane 2 as close to 90 ° as possible.

  FIG. 10 is a side view schematically showing a configuration of a substrate cleaning apparatus 25 according to another embodiment of the present invention. The substrate cleaning apparatus 25 includes a substrate holding unit (not shown) that tilts and holds the substrate 1 so as to form an inclination angle θ1 with respect to the horizontal plane 2, and a pure water injection unit 26 that sprays pure water onto the surface to be cleaned 1a of the substrate 1. It is comprised including.

  Although the substrate holding means is not shown, for example, a plate member made of metal or synthetic resin on which the substrate 1 is placed, and a plate member support means for supporting the plate member so that the plate member can be angularly displaced with respect to the horizontal plane 2. It is realizable with the apparatus containing these. Furthermore, the plate-like member can be provided with a holder for fixing the substrate 1. The substrate 1 is placed on the surface of the plate-like member, the plate-like member is angularly displaced by the plate-like member supporting means, and the angle formed by the plate-like member with respect to the horizontal plane 2 is appropriately adjusted, whereby the horizontal plane of the substrate 1 is obtained. 2 can be determined.

  The pure water injection means 26 includes a pressure-resistant nozzle 4 that sprays pure water onto the surface to be cleaned 1 a of the substrate 1, an arm 27 that supports the pressure-resistant nozzle 4 so as to be angularly displaceable, and supports the arm 27 and supports the substrate 1. The slider 28 is configured to be movable along a guide 29 arranged in parallel, and includes pure water supply means (not shown). The guide 29 and the slider 28 are realized by, for example, a ball screw that is rotationally driven by a motor and a female screw member that is screwed into the ball screw.

FIG. 11A is a perspective view showing the appearance of the pressure-resistant nozzle 4. FIG. 11B is a plan view schematically showing the configuration of the pure water injection surface 30 in the pressure-resistant nozzle 4. A plurality of circular injection holes 31 are formed in a straight line on the pure water injection surface 30 of the pressure-resistant nozzle 4. The diameter d2 of the circular injection hole 31 is 200 μm or less in order to reduce the thickness of the pure water liquid film 7 formed on the surface 1a to be cleaned of the substrate 1 to less than 1 mm and improve the substrate contaminant removal performance. Preferably, from 10 μm
100 μm is particularly preferable. Moreover, it is preferable that the center space | interval of the adjacent circular injection hole 31, ie, formation pitch d3, satisfy | fills following Formula (1).
2 × d2 ≦ d3 ≦ 3 × d2 (1)

  Specifically, for example, there is a pressure-resistant nozzle in which the diameter d2 of the circular injection holes 31 is 30 μm and the formation pitch d3 of the circular injection holes 31 is 60 μm. When the pure water supplied to the pressure-resistant nozzle is pressurized to 4 MPa, the thickness of the liquid film 7 generated 20 mm downstream from the pure water collision point on the surface to be cleaned 1a of the substrate 1 is as extremely small as 100 to 150 μm. At this time, the ultrapure water flowing over the surface 1a to be cleaned of the substrate 1 has an average speed of 10 m / s or more. However, the numerical value and the formula (1) indicating the configuration of the pressure-resistant nozzle 4 are examples for generating the liquid film 7 on the surface to be cleaned 1a of the substrate 1, and in the present invention, the substrate is formed by the liquid film 7. In removing contaminants, the configuration of the pressure-resistant nozzle 4 is not limited.

  When pure water is sprayed from the pressure-resistant nozzle 4 onto the surface to be cleaned 1a of the substrate 1 held at an inclination angle θ1 with respect to the horizontal plane 2, a pure water liquid film 7 is formed on the surface to be cleaned 1a. .

  FIG. 12A is a perspective view showing the appearance of another embodiment of the pressure-resistant nozzle 32. FIG. 12B is a plan view schematically showing the configuration of the pure water ejection surface 33 in the pressure-resistant nozzle 32. A slit-like injection hole 34 is formed in the pure water injection surface 33 of the pressure-resistant nozzle 32. The gap d4 of the slit-shaped injection hole 34 is 200 μm or less in order to reduce the thickness of the pure water liquid film 7 formed on the surface 1a to be cleaned of the substrate 1 to less than 1 mm and improve the substrate contaminant removal performance. Is preferable, and 10 μm to 100 μm is particularly preferable. Specifically, for example, a pressure-resistant nozzle in which the gap d4 of the slit-like injection hole 34 is 30 μm can be mentioned. When the ultrapure water supplied to the pressure-resistant nozzle is pressurized to 4 MPa, the thickness of the liquid film 7 generated 20 mm downstream from the ultrapure water collision point on the surface to be cleaned 1a of the substrate 1 is as extremely thin as 100 to 150 μm. At this time, the ultrapure water flowing over the surface 1a to be cleaned of the substrate 1 has an average speed of 10 m / s or more. However, the numerical value indicating the configuration of the pressure-resistant nozzle 32 is an example for generating the liquid film 7 on the surface 1a to be cleaned of the substrate 1, and the substrate contaminants are removed by the liquid film 7 in the present invention. In this case, the configuration of the pressure-resistant nozzle 32 is not limited.

  When pure water is sprayed from the pressure-resistant nozzle 32 onto the surface to be cleaned 1a of the substrate 1 held at an inclination angle θ1 with respect to the horizontal plane 2, a pure water liquid film 7 is formed on the surface to be cleaned 1a. .

  Returning to FIG. 10, the arm 27 supports the pressure-resistant nozzle 4 so as to be angularly displaceable. Therefore, the pure water injection angle θ2 of the pressure-resistant nozzle 4 with respect to the surface to be cleaned 1a of the substrate 1 can be adjusted as appropriate. The arm 27 is supported by a slider 28, and the slider 28 is disposed so as to be movable along a guide 29. Since the guide 29 is arranged in parallel to the surface 1a to be processed of the substrate 1, the arm 27 and thus the pressure-resistant nozzle 4 are supported by the slider 28 so as to move up and down in parallel to the surface 1a to be processed of the substrate 1. It will be.

  The pure water supply means includes, for example, a pure water storage tank that stores pure water, a pressure-resistant hose that has one end connected to the pure water storage tank and the other end connected to the pressure-resistant nozzle 4, and pressurizes pure water. And a pressurizing pump for feeding. Of course, the present invention is not limited to this configuration, and a general method for supplying a liquid to the nozzle can be employed.

  According to the substrate cleaning apparatus 25, for example, the surface to be cleaned 1a of the substrate 1 is cleaned as follows. First, the position of the pressure-resistant nozzle 4 is adjusted by moving the slider 28 so that the point where the pure water jetted from the pressure-resistant nozzle 4 reaches the top of the substrate 1 in the vertical direction. Next, injection of pure water 35 pressurized from the pressure-resistant nozzle 4 is started, and a thin liquid film 7 is formed on the surface to be cleaned 1 a of the substrate 1. The liquid flow in the liquid film 7 decelerates toward the lower side of the substrate 1 due to the viscosity of the pure water itself, friction with the surface to be cleaned 1a, and the like, and the film thickness of the liquid film 7 increases accordingly. Then, in the cleaning execution area 8 which is an area from a position directly below the point where the pure water 35 reaches on the surface 1a to be cleaned to several centimeters below, substrate contaminants attached to the surface 1a to be cleaned are removed. Therefore, when the pressure-resistant nozzle 4 is moved downward, the cleaning execution region 8 can be continuously generated downward toward the substrate 1 and the entire substrate 1 can be cleaned. Further, by moving the pressure-resistant nozzle 4 from the upper side to the lower side of the substrate 1, the substrate is peeled from the surface to be cleaned 1 a, and the substrate contaminants eluted in the liquid film 7 are not reattached to the substrate 1. Can be discharged. Finally, when the cleaning execution area 8 reaches the lowest part of the surface 1a to be cleaned of the substrate 1, the injection of pure water by the pressure-resistant nozzle 4 is stopped, and the cleaning of the substrate 1 is completed.

It is a side view for demonstrating the board | substrate cleaning method of this invention. It is a perspective view for demonstrating the board | substrate cleaning method of this invention. It is sectional drawing which shows typically the state of the liquid film in a cleaning execution area | region. It is sectional drawing which shows typically the mechanism in which microparticles | fine-particles are removed in the washing | cleaning execution area | region. It is sectional drawing which shows typically the state of the liquid film which arises on the to-be-cleaned surface of the board | substrate mounted in a horizontal surface. It is sectional drawing which shows typically the state of the liquid film which arises on the to-be-cleaned surface of the board | substrate in the method of this invention. It is sectional drawing which shows typically the mechanism which removes a metal particle by the method of this invention. It is sectional drawing which shows typically the mechanism which removes a metal compound with the method of this invention. It is sectional drawing which shows typically the mechanism which removes organic substance by the method of this invention. It is a side view which shows typically the structure of the board | substrate cleaning apparatus which is another form of implementation of this invention. FIG. 11A is a perspective view showing the appearance of the pressure-resistant nozzle. FIG.11 (b) is a top view which shows typically the structure of the pure water injection surface in a pressure | voltage resistant nozzle. Fig.12 (a) is a perspective view which shows the external appearance of the pressure | voltage resistant nozzle of another form. FIG.12 (b) is a top view which shows typically the structure of the pure water injection surface in the pressure-resistant nozzle of another form. It is a side view which shows typically the structure of the board | substrate cleaning apparatus of a prior art. It is a side view which shows the conveyance attitude | position of the board | substrate in the board | substrate cleaning apparatus of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 1a Surface to be cleaned 2 Horizontal surface 3 Pure water injection means 4, 32 Pressure resistant nozzle 5 Injection hole 6 Pressure resistant piping 7, 15 Liquid film 7a, 15a Liquid film surface 8 Cleaning execution area 9, 10, 11, 12 area 9a, 9b , 9c, 9d, 9e Liquid flow 10a, 10b, 10c, 10d Liquid flow 11a, 11b, 11c, 11d Liquid flow 12a, 12b, 12c, 12d Liquid flow 9x, 10x, 11x, 12x Velocity lines 13a, 13b, 13c Fine particles DESCRIPTION OF SYMBOLS 14 Stress 16 High-pressure area | region 17 Main stream 18a, 18b, 18c Metal particle 19 Metal atom bond 20a, 20b, 20c Metal compound 21 Metal compound bond 22a, 22b, 22c Organic substance 23 Carbon bond 25 Substrate cleaning apparatus 26 Pure water injection means 27 Arm 28 Slider 29 Guide 30, 33 Pure water injection surface 31 Circular injection hole 34 Slit shape Injection hole 35 Pure water

Claims (9)

  Pure water in a pressurized state is sprayed from the pure water injection position spaced from the surface to be cleaned onto the surface to be cleaned placed at an angle with respect to the horizontal plane, A substrate cleaning method comprising: generating a liquid film that is a one-way flow from the upper part to the lower part of the upper part to remove substrate contaminants on the surface to be cleaned.   2. The substrate cleaning method according to claim 1, wherein the substrate contaminant is one or more selected from fine particles, metal particles, metal compounds and organic substances.   3. The substrate cleaning method according to claim 1, wherein an angle formed by the substrate with respect to the horizontal plane is 5 degrees or more and 90 degrees or less.   The substrate cleaning method according to claim 1, wherein the thickness of the liquid film is less than 1 mm.   The substrate cleaning method according to claim 1, wherein a distance between the surface to be cleaned and the pure water injection position is 1 mm or more and 50 mm or less. A substrate is cleaned by generating a liquid film that flows in one direction from the top to the bottom on the surface to be cleaned on the surface to be cleaned placed at an angle with respect to the horizontal plane. A substrate cleaning apparatus for removing substrate contaminants adhering to a surface,
Substrate holding means for holding the substrate in a posture that makes an angle with respect to a horizontal plane;
Substrate cleaning characterized by comprising pure water spraying means for spraying pure water in a pressurized state onto the surface to be cleaned, which is provided at an interval with respect to the surface to be cleaned held by the substrate holding means apparatus.   The pure water injection means is a nozzle having a plurality of pure water injection holes having a diameter of 200 μm or less and formed so that the pure water injection holes are arranged in a straight line. Substrate cleaning device.   7. The substrate cleaning apparatus according to claim 6, wherein the pure water injection means is a slit nozzle having an opening gap of 200 [mu] m or less.   The substrate cleaning apparatus according to claim 6, further comprising a moving unit that moves the pure water injection unit up and down along the surface to be cleaned of the substrate.

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