JP2012200679A - Substrate cleaning device and substrate cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for easily cleaning a substrate using a small amount of cleaning liquid.SOLUTION: After a cleaning liquid A is supplied from a cleaning nozzle 2 to an upper surface of a substrate G moving horizontally in a horizontal attitude, the substrate G passes between magnetic field producing members 3, 4 provided on a downstream side from the cleaning nozzle 2 on a movement path of the substrate G. The cleaning liquid A supplied to the upper surface of the substrate G is diamagnetic, so that the cleaning liquid is blocked by operation of a strong magnetic field formed between the magnetic field forming members 3, 4. Consequently, the cleaning liquid A is removed by draining the upper surface of the substrate G.

Description

  The present invention relates to the technical field of cleaning a substrate with a cleaning liquid.

  In recent years, glass substrates (FPD substrates) for FPDs (flat panel displays) have become larger (for example, several m × several meters), making it difficult to apply spin cleaning methods like semiconductor wafers. Yes. On the other hand, in the horizontal cleaning in which the cleaning liquid is sprayed from the nozzle to the FPD substrate being transported horizontally, the stagnation (stagnation) of the cleaning liquid occurs on the substrate, the replacement efficiency of the sprayed cleaning liquid is low, and the amount of cleaning liquid used is low. There are problems such as increasing. In the horizontal cleaning, in order to overcome the above-mentioned drawbacks, for example, a so-called air knife that blows an air flow from the nozzle to the substrate may be used together, but a large amount of air is required, and the cleaning liquid is isopropyl alcohol or the like. In this case, since the mist of the chemical solution is taken into the air, it is not a preferable method from the viewpoint of environmental pollution. Further, the cleaning liquid on the surface of the substrate is volatilized by the air knife, and the cleaning liquid may have a stain residue or foreign matter may be fixed.

  Also known is a method of cleaning the FPD substrate in an inclined state. This method prevents the staying of the cleaning liquid, prevents re-attachment of foreign matter to the substrate and the remaining stain of the cleaning liquid, reduces the amount of cleaning liquid used, and rinse time. There are advantages such as shortening. On the other hand, since the inclined cleaning must be transported at an inclination, the transport mechanism becomes complicated and the manufacturing cost increases. In addition, the inclined cleaning has a problem that the substrate jumps at the time of transition between parallel conveyance and inclined conveyance. Further, since gravity is used for draining the cleaning liquid, the cleaning liquid is accelerated only by 1 G (gravity acceleration) at the maximum, so that the liquid moving force is insufficient as compared with the spin cleaning method.

  Patent Document 1 discloses a technique for leveling a coating film by the Moses effect and making the film thickness uniform by scanning a magnetic field generated by an electromagnet from the upper side of a substrate coated with a coating agent on the surface. However, it is not applied to the cleaning of the substrate as in the present invention, and the problem is different.

JP-A-10-137666

  The present invention has been made under such a background, and an object of the present invention is to provide a technique for simply cleaning a substrate while keeping the amount of cleaning liquid small.

The substrate cleaning apparatus of the present invention is
A magnetic field forming member for forming a magnetic field;
A moving mechanism for moving the substrate made of a non-magnetic material relative to the magnetic field forming member so as to pass the magnetic field relatively along the surface of the substrate;
A cleaning liquid supply unit for supplying a cleaning liquid to the surface of the substrate on the upstream side of the magnetic field forming member in the movement path of the substrate relative to the magnetic field;
When the substrate relatively passes through the magnetic field, the cleaning liquid is pushed back with respect to the relative traveling direction of the substrate by the magnetic field gradient, and is removed from the substrate.

The substrate cleaning method of the present invention comprises:
Forming a magnetic field with a magnetic field forming member;
A step of moving a substrate made of a non-magnetic material relative to the magnetic field forming member in order to pass the magnetic field relatively along the surface of the substrate;
Supplying a cleaning liquid to the surface of the substrate on the upstream side of the magnetic field forming member in the path of movement of the substrate relative to the magnetic field, and
When the substrate relatively passes through the magnetic field, the cleaning liquid is pushed back with respect to the relative traveling direction of the substrate by the magnetic field gradient, and is removed from the substrate.

  In the present invention, a magnetic field gradient is formed, and this is used to press the cleaning liquid along the surface of the substrate and remove it from the substrate. Therefore, it is possible to clean the substrate while reducing contamination to the surrounding environment with a small amount of cleaning liquid with a simple apparatus configuration as compared with the prior art.

It is a vertical side view which shows the substrate cleaning apparatus in this embodiment. It is a top view which shows the said board | substrate cleaning apparatus. It is a perspective view which shows the external appearance of the said board | substrate cleaning apparatus. It is a perspective view which shows the inside of the said board | substrate cleaning apparatus. It is a perspective view which shows the magnetic field formation member in the said board | substrate cleaning apparatus. It is an effect | action figure explaining the washing | cleaning process in this embodiment. It is a top view which shows the 1st modification of the board | substrate cleaning apparatus in this embodiment. It is a vertical side view which shows the said 1st modification. It is a vertical side view which shows the 2nd modification of the board | substrate cleaning apparatus in this embodiment. It is a vertical side view which shows the 3rd modification of the substrate cleaning apparatus in this embodiment. It is a side view which shows the experimental apparatus in a present Example. It is a perspective view which shows the magnetic field formation member in a present Example. It is a scatter diagram which shows the relationship between the amount of liquids in a present Example, and the magnitude | size of the clearance gap between magnetic field formation members.

  As an embodiment of the substrate cleaning apparatus of the present invention, an apparatus for cleaning a square glass substrate G which is an FPD substrate will be described. First, the structure of the substrate cleaning apparatus will be described with reference to FIGS. Reference numeral 1 denotes a housing, and a substrate G carrying-in port 11 and a substrate G carrying-out port 12 are provided on one side wall of the housing 1, and these can be opened and closed by shutters 13 and 14, respectively. ing. In the housing 1, a plurality of transport rollers 15 and guide rollers 16 extending horizontally in the left-right direction (Y direction) are arranged in the front-rear direction (X direction) to form a movement path 17 for the substrate G. Yes. The transport roller 15 is a drive roller that is rotationally driven by a motor that is a rotation mechanism and horizontally transports the substrate G placed thereon, and the guide roller 16 is a driven roller that guides the substrate G. The separation interval between the transport roller 15 and the transport roller 15 is set to be shorter than the length of one side along the movement path 17 of the substrate G. In this example, in order to perform stable transport, the length of the one side is set. On the other hand, a plurality of conveying rollers 15 are arranged. In addition, the number of guide rollers 16 to be installed is convenient because of space limitations.

  The length of the movement path 17 is set to be larger than twice the one side of the substrate G. When the traveling direction of the substrate G is the front side, the rear region corresponds to the carry-in region corresponding to the carry-in port 11, The area on the front side is a carry-out area corresponding to the carry-out port 12. Below each of the carry-in area and the carry-out area, a transfer arm 7 (see FIG. 3), which is a transfer mechanism for the substrate G provided outside the substrate cleaning apparatus, and a transfer roller 15 and a guide in the carry-in area and the carry-out area. Elevating pins 22 and 23 for mediating delivery of the substrate G to and from the roller 16 are provided. The lift pins 22 and 23 are provided at positions that do not interfere with the transfer arm 7 when the substrate G is transferred.

  A cleaning nozzle 2 extending in the width direction of the substrate G is provided slightly upstream (upstream) from the central portion in the front-rear direction of the moving path 17, and the width direction of the substrate G from the lower discharge port ( A cleaning liquid, for example, a chemical solution such as pure water or isopropyl alcohol can be supplied to the whole (width direction in the movement path 17). This discharge port is configured by arranging slits or small-diameter pores extending in the Y direction at many intervals in the Y direction. Further, on the downstream side of the cleaning nozzle 2 in the movement path 17 (the front side in the movement path 17), as shown in FIG. 4, it extends horizontally in the width direction of the movement path 17 (extends perpendicularly to the movement path 17). Square magnetic field forming members 3 and 4 are provided to face each other so as to sandwich the moving path 17 in the vertical direction. Of these, the magnetic field forming member 3 located above the moving path 17 extends in the Y direction between two rectangular magnets, for example, permanent magnets 31 and 32, each extending in parallel with the Y direction, as shown in FIG. It is configured as a structure sandwiching a core member 33 that is a rectangular magnetic body. The permanent magnets 31 and 32 are configured such that both magnetic poles are aligned in the moving direction of the substrate G, and N poles that are the same magnetic poles, for example, face each other with the core member 33 therebetween.

  On the other hand, as shown in FIG. 5, the magnetic field forming member 4 located below the movement path 17 sandwiches a core member 43 that is a rectangular magnetic body between two rectangular magnets, for example, permanent magnets 41 and 42. The outer appearance is the same as that of the magnetic field forming member 3 on the upper side, but the permanent magnets 41 and 42 are arranged opposite to the magnetic field forming member 3 in terms of the arrangement of both magnetic poles. Yes. That is, in this example, the south poles of the permanent magnets 41 and 42 are configured to face each other with the core member 43 interposed therebetween. With this configuration, a strong magnetic field is formed between the magnetic field forming members 3 and 4. As a material of the permanent magnets 31, 32, 41, 42, for example, neodymium or the like is used, and as the core members 33, 43, a metal such as iron having a high saturation magnetic flux density is used. The size (gap between magnets) L of these magnetic field forming members 3 and 4 is, for example, 2 mm to 5 mm. Further, a drainage port 18 for discharging the cleaning liquid used for cleaning the substrate G to the outside of the casing 1 is provided at the bottom of the casing 1. Further, reference numeral 8 in FIG. 1 denotes a control unit that controls the supply of the cleaning liquid, the elevation pins 22 and 23 and the conveyance roller 15.

  Next, the effect | action in this embodiment is demonstrated using FIG. First, as shown in FIG. 3, the substrate G is transported into the housing 1 by the transport arm 7 from the outside through the transport port 11 where the shutter 13 is opened, and then the lift pins are transported by the transport roller 15 and the guide roller 16. 1 or between the guide rollers 16 and 16, and is placed on the conveyance roller 15 and the guide roller 16 side by side as shown by a solid line in FIG. Is done.

  Next, the cleaning liquid A is discharged by the cleaning nozzle 2 and the transport roller 15 is driven. The substrate G is pushed forward by the transport roller 15 and moves forward while being guided by the guide roller 16, and the cleaning liquid A is sequentially supplied from the front end side. As shown in FIG. And part of it spreads toward the rear end side of the substrate G. When the substrate G passes through the area sandwiched between the magnetic field forming members 3 and 4, the cleaning liquid A also passes through the area between the magnetic field forming members 3 and 4 due to the advance of the cleaning liquid A and the discharge force of the liquid from the cleaning nozzle 2. However, since the cleaning liquid A is diamagnetic, it is repelled and pushed back by the strong magnetic field formed by the magnetic field forming members 3 and 4. That is, a large magnetic field gradient is formed in which the magnetic field gradually increases from the upstream side of the region in the moving path 17 toward the region, and the cleaning liquid A tries to move to the weak magnetic field side along the magnetic field gradient. Therefore, as shown in FIG. 6 (b), the forward movement of the cleaning liquid A is prevented at a position where the force that the cleaning liquid A moves forward and the force that is pushed back are balanced. Therefore, when the substrate G is advanced in a state where the cleaning liquid A is continuously discharged from the cleaning nozzle 2, the cleaning liquid A spreads downstream from the cleaning nozzle 2 from both left and right edges, depending on the moving speed. Spill down. Further, most of the cleaning liquid A spreading upstream from the cleaning nozzle 2 flows down from the rear end side of the substrate G (FIG. 6C). When the substrate G passes under the cleaning nozzle 2 in this way, the cleaning liquid A comes into contact with the entire surface of the substrate G to perform the cleaning process, and the cleaning liquid A on the substrate G has the rear ends at the magnetic field forming members 3, 4. When it has passed between the two, it is pushed rearward and removed from the substrate G, thus cleaning and draining are performed (FIG. 6D). The cleaning liquid A spilled from the substrate G to the bottom of the housing 1 is drained and processed through the drainage port 18 to the drainage treatment system 19 outside the substrate cleaning apparatus. The substrate G which has been cleaned and drained and is transported to the carry-out area by the transport roller 15 and the guide roller 16 is transferred to the transport arm 7 via the lift pins 23, and is transferred to the outside of the substrate cleaning apparatus via the transport outlet 12. It is carried out to.

  In the above-described embodiment, after supplying the cleaning liquid A to the substrate G, the cleaning liquid A passes through the substrate G using a magnetic field gradient between a locally formed strong magnetic field and the surroundings. Thus, the cleaning liquid A is removed by draining the liquid on the surface of the substrate G. Accordingly, since it is not necessary to incline the substrate G as in the case of the inclined cleaning, the mechanism of the substrate cleaning apparatus can be simplified and the manufacturing cost can be reduced, and the substrate G at the time of changing the attitude between the inclined attitude and the horizontal attitude can be reduced. The problem of splashing is eliminated. In addition, when using an air knife that is used in combination with horizontal cleaning, the liquid is removed while volatilizing it, and thus there is a problem such as a stain residue of the cleaning liquid A as described above. Since it is removed from the surface of the substrate G by applying pressure, there is no such problem. Further, since it is not necessary to exhaust a large amount of air containing the cleaning liquid A, it is excellent in terms of reducing environmental pollution.

  In the above-described embodiment, the magnetic field forming members 3 and 4 are provided so that the longitudinal direction is horizontally orthogonal to the moving direction of the substrate G. However, as shown in FIGS. 3a and 4a are provided with rotation shafts 37a and 47a that are rotatable around the vertical axis at the center in the longitudinal direction of each of them, and the magnetic field forming members 3a and 4a are respectively rotated by the motors 36a and 46a via the rotation shafts 37a and 47a. You may comprise so that it can rotate in a horizontal direction. In this case, the direction of the magnetic field forming members 3a and 4a with respect to the traveling direction of the substrate G can be adjusted, and the direction of the magnetic field forming members 3a and 4a is orthogonal to the traveling direction of the substrate G as in the previous embodiment. It can be set so as to extend (in the width direction of the substrate G), or can be set so as to cross obliquely with respect to the traveling direction of the substrate G as shown in FIG. When set obliquely, for example, when the direction of the magnetic field forming members 3a, 4a is set so that the left end side is the back side when viewed from the upstream side in the moving direction of the substrate G, the passage is blocked by a strong magnetic field. Since the cleaning liquid A is directed toward the left end side of the substrate G along the magnetic field forming members 3a and 4a, a liquid flow is formed in one direction. Is removed. 7 and 8, the conveyance roller 15 and the guide roller 16 are not shown.

  In the above-described embodiment, the cleaning is performed while the cleaning nozzle 2 and the magnetic field forming members 3 and 4 are fixed and the substrate G is moved. However, as illustrated in FIG. You may wash | clean by moving the battlefield nozzle 2b and the magnetic field formation member 3b along the linear guide rail 5 made. Further, cleaning may be performed while moving both the substrate G, the cleaning nozzle 2 and the magnetic field forming members 3 and 4. In FIG. 9, the lifting pins that transfer the substrate G between the transfer arm 7 and the substrate holding member 51 are not shown.

  Another embodiment of the present invention will be described with reference to FIG. A plate-like base 9 is horizontally provided in a housing (not shown) of the substrate cleaning apparatus in this embodiment. A plurality of support members 91 are vertically provided on the upper surface of the base 9, and a placement portion 92 for placing the substrate G is provided on the upper end thereof. The support member 91 and the mounting portion 92 are provided at positions that do not interfere with the transport arm that transports the substrate G into the substrate cleaning apparatus when the substrate G is delivered. As will be described later, the mounting portion 92 at the end of the base 9 that is lowered when tilted with respect to the horizontal axis (left side in FIG. 10) has a locking member 93 having an L-shaped longitudinal section. Even if the base 9 is tilted, the substrate G placed on the placement portion 92 is configured not to slide down. The base 9 is provided with a not-shown tilting mechanism such as a motor via a tilting shaft 94 extending in the horizontal direction.

  A cleaning nozzle 2d is provided at a position above the substrate G placed on the mounting table 92. The length of the base 9 (perpendicular to the inclined axis 94 and mounted) by a guide rail and a moving mechanism (not shown). In a direction parallel to the substrate G to be formed). A magnetic field forming member 3d is provided above the substrate G and can be moved in the length direction of the base 9 by a guide rail or a moving mechanism (not shown). The guide mechanism of the cleaning nozzle 2d can be tilted in accordance with the tilt of the substrate G from the horizontal position. The detailed configuration of the cleaning nozzle 2d and the magnetic field forming member 3d is the same as that of the cleaning nozzle 2 and the magnetic field forming member 3 in the first embodiment described above.

Then, the effect | action in this embodiment is demonstrated. First, in a state where the base 9 is in a horizontal posture, the substrate G is carried in from the outside of the substrate cleaning apparatus by the transfer arm and placed on the placement unit 92. Then, the cleaning liquid A is supplied to the entire surface of the substrate G by, for example, moving the cleaning nozzle 2 d while discharging the cleaning liquid A from the cleaning nozzle 2 d and scanning the entire surface of the substrate G. The cleaning nozzle 2d may be moved from the bottom to the top in accordance with the inclination of the substrate G. Thereafter, the base 9 is tilted by the tilt mechanism (not shown), so that the cleaning liquid A supplied to the surface of the substrate G naturally flows down due to the action of gravity and falls from the substrate G. At this time, a part of the cleaning liquid A remains on the surface of the substrate G. Subsequently, the magnetic field forming member 3d is moved from the top to the bottom in the tilt direction of the base 9 so as to scan the entire surface of the substrate G. At this time, the cleaning liquid A remaining on the substrate G by being pressed by the magnetic field gradient formed by the magnetic field forming member 3d is drained. Here, the magnetic field forming member 3d may reciprocate a plurality of times until the cleaning liquid A is completely drained. Thereafter, the base 9 is returned to the horizontal position by the tilt mechanism, and the substrate G that has been cleaned is carried out of the apparatus by the transfer arm.
In this embodiment, since the vertical component of the gravity of the cleaning liquid A is added according to the inclination as the moving force of the cleaning liquid A, there is an advantage that the liquid draining performance of the cleaning liquid A is improved as compared with the first embodiment described above.

In the first embodiment described above, the magnetic field forming members 3 and 4 longer than the width of the substrate G are fixed and washed so as to extend over the entire width of the substrate G. However, the magnetic field formation shorter than the width of the substrate G is formed. Cleaning is performed by scanning the entire surface of the substrate G by moving the substrate G relative to the magnetic field forming member many times while shifting the magnetic field forming member in the width direction of the substrate G using the member. May be.
In the first embodiment described above, the magnetic field forming members 3 and 4 are provided on both the upper and lower sides of the moving path 17, but may be provided on only one of the upper and lower sides.
In the above-described embodiment, the draining of the cleaning liquid is described. However, the present invention is not limited to this, and may be used, for example, for removing or applying a chemical liquid.
In the above-described embodiment, a permanent magnet is used as the magnet. However, the present invention is not limited to this, and an electromagnet may be used, for example.

  Below, the evaluation test of this invention was done using the experimental apparatus shown in FIG. Specifically, an experiment was conducted to confirm whether or not the liquid droplets moved by moving the magnetic field forming member. In FIG. 11, 6 is a moving surface forming member made of silicon and having a thickness of 0.75 mm, and 3 c and 4 c are magnetic field forming members respectively disposed on both surfaces of the moving surface forming member 6. As shown in FIG. 12, the magnetic field forming member 3c is configured so as to surround a quadrangular prism core member 33c having a square cross section with four permanent magnets 31c, 32c, 34c, and 35c. The material of the core member 33c is iron, and one side of the square of the cross section is 10 mm. The permanent magnets 31c, 32c, 34c, and 35c are made of neodymium and arranged so that the outside is an N pole, and one side of the magnetic field forming member 3c is 50 mm. The magnetic field forming member 4c is configured by the core member 43c and the four permanent magnets 41c, 42c, 44c, and 45c in the same manner as the magnetic field forming member 3c, but the direction of the magnetic poles of the permanent magnets 41c, 42c, 44c, and 45c is as follows. It arrange | positions so that an outer side may become a south pole. Then, the gap (inter-magnet gap) L between the magnetic field forming members 3c and 4c and the appropriate amount of liquid were changed, and it was visually confirmed whether or not the droplet 61 moved with the movement of the magnetic field forming members 3c and 4c. The droplet 61 having a diameter of 5 mm to 10 mm corresponds to an appropriate liquid amount of 20 μl to 100 μl.

  This result is shown in FIG. In the figure, the vertical axis indicates the gap between the magnets, the horizontal axis indicates the appropriate amount of liquid, the ▪ indicates the droplet 61 moved by the movement of the magnetic field forming members 3c and 4c, and the □ indicates the droplet 61 that has not moved. As a result, it was recognized that the droplet 61 moved on the surface of the moving surface forming member 6 with the movement of the magnetic field forming members 3c and 4c. Further, it is understood that when the droplet amount is small, in order to move the droplet 61, it is necessary to reduce the gap L between the magnetic field forming members 3c and 4c to increase the magnetic flux density. In other words, this means that the larger the appropriate amount of liquid, the easier it is to move the liquid. The reason is that the greater the appropriate amount of liquid, the smaller the resistance to movement of the droplet due to the specific surface tension. From this, it is presumed that the cleaning liquid can be drained also in the present invention having a larger liquid volume than the present embodiment.

A Cleaning liquid G Substrate 1 Housing 2 Cleaning nozzle 3 Upper magnetic field forming member 4 Lower magnetic field forming members 31, 32, 41, 42
Permanent magnets 33, 43
Core member

Claims (4)

A magnetic field forming member for forming a magnetic field;
A moving mechanism for moving the substrate made of a non-magnetic material relative to the magnetic field forming member so as to pass the magnetic field relatively along the surface of the substrate;
A cleaning liquid supply unit for supplying a cleaning liquid to the surface of the substrate on the upstream side of the magnetic field forming member in the movement path of the substrate relative to the magnetic field;
The substrate cleaning apparatus, wherein when the substrate relatively passes through the magnetic field, the cleaning liquid is pushed back with respect to the relative traveling direction of the substrate by a magnetic field gradient and removed from the substrate.   The substrate cleaning apparatus according to claim 1, wherein the moving mechanism is configured to transport the substrate horizontally. The magnetic field forming member is configured to extend over the entire width direction of the substrate,
The substrate cleaning apparatus according to claim 1, wherein the moving mechanism is configured to move the substrate so as to intersect a direction in which the magnetic field forming member extends. Forming a magnetic field with a magnetic field forming member;
A step of moving a substrate made of a non-magnetic material relative to the magnetic field forming member in order to pass the magnetic field relatively along the surface of the substrate;
Supplying a cleaning liquid to the surface of the substrate on the upstream side of the magnetic field forming member in the path of movement of the substrate relative to the magnetic field, and
The substrate cleaning method, wherein when the substrate relatively passes through the magnetic field, the cleaning liquid is pushed back with respect to the relative traveling direction of the substrate by a magnetic field gradient and removed from the substrate.

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