KR20110103333A - The sensing method of the alien substance of the back side and the sensing apparatus of the alien substance of the back side and coating apparatus - Google Patents

Abstract

[Problem] Accurate and reliable detection of harmful back surface foreign matter which may damage the upper surface of the substrate by slit nozzle in the floating spinless coating method.
[Resolution] The resist coating device is provided with a back surface foreign matter detection device 50, which is harmful (i.e., may damage the slit nozzle 14 by rubbing the top surface of the substrate G). ) Can be detected more reliably on the upstream side of the substrate conveyance direction (X direction) than the slit nozzle 14. Then, in response to the alarm signal WS generated when the back surface foreign matter detection device 50 detects such a harmful back surface foreign material Q, the main control part 52 passes through the nozzle elevating mechanism 36 to the slit nozzle 14. By immediately moving up), the slit nozzle 14 can move the increased portion G _Q of the substrate G away (sliding contact or collision can be avoided), thereby preventing damage to the slit nozzle 14. do.

Description

The back surface foreign matter detection method and the back surface foreign matter detection device and coating device {THE SENSING METHOD OF THE ALIEN SUBSTANCE OF THE BACK SIDE AND THE SENSING APPARATUS OF THE ALIEN SUBSTANCE OF THE BACK SIDE AND COATING APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for applying a processing liquid to a substrate to be processed on a floating stage, and more particularly, to a back foreign matter detection method and a back foreign matter detection apparatus for detecting undesirable foreign matter adhering to the back surface of a substrate.

In the photolithography process in the manufacturing process of a flat panel display (FPD) such as an LCD, a spinless coating a resist liquid on a substrate to be processed (such as a glass substrate) using an elongated slit nozzle having a slit-shaped discharge port. The coating method of is frequently used.

As one form of such a spinless coating method, a substrate floating mechanism is assembled to a stage for supporting a substrate, the substrate is floated in the air on this floating stage, and conveyed in one horizontal direction (stage longitudinal direction), and the predetermined value during conveyance A floating method in which the resist liquid is applied from one end to the other on the substrate by discharging the resist liquid in a band form from the slit nozzle disposed above the stage at the position toward the substrate passing directly below. This is known.

In this floating spinless coating method, in order to uniformly form a coating film of a resist liquid on a substrate at a predetermined film thickness, a minute gap of about 100 μm is usually formed between the discharge port of the slit nozzle and the substrate. It is required to remain at or near the set point.

In order to satisfy this requirement, a resist coating apparatus employing a floating spinless coating method is provided with a plurality of blowout outlets for ejecting a gas of high pressure or positive pressure, for example air, at a predetermined density in substantially the entire area of the floating stage. In addition, a suction port for suctioning air at negative pressure is mixed in the jet port in the coating area set as the area immediately before and after the slit nozzle on the floating stage. In this application area, the pressure of the vertical upward pressure applied from the jet port and the vertical downward pressure applied from the suction port are balanced with respect to the substrate passing therethrough, thereby precisely controlling the floating pressure applied to the substrate. The floating height of the board | substrate is made to match a set value (usually 50 micrometers or less) (for example, patent document 1).

Japanese Patent Laid-Open No. 2007-190483

In the spinless coating method of the above-mentioned floating method, as in the other spinless coating method, foreign matters may be attached to the substrate immediately before the coating treatment, and the foreign material or the upper surface of the substrate may be attached to the tip (discharge port) of the slit nozzle. If rubbed, the slit nozzle may be damaged. If the discharge port of the slit nozzle is damaged at all, the strip-shaped discharge flow becomes nonuniform, which leads directly to the decrease in the film quality of the coating film. Since the slit nozzle is very expensive and the parts can not be easily replaced at low cost, early detection of foreign matter adhering to the substrate is an important problem.

As a foreign material on a board | substrate, there exist two types of the surface foreign material adhering to the surface (upper surface) of a board | substrate, and the back surface foreign material adhering to the back surface (lower surface) of a board | substrate. Among them, the surface foreign matter is harmful from the size of the light shielding portion or the light receiving amount reduction of the light beam (ie, may be directly rubbed into the slit nozzle, and may be damaged by using an optical sensor that traverses the light beam to rub the upper surface of the substrate). Foreign matter can be detected easily. Therefore, it was possible to cope with the conventional foreign matter detection device.

However, the foreign matter on the back surface is troublesome in the spinless coating method of the floating method. In other words, in the spinless coating method in which the substrate is placed on the stage and fixed by adsorption, the increase in thickness of the substrate due to the back surface foreign matter is the same as that of the surface foreign matter, so that the light-shielding portion or the light-receiving amount reduction of the light beam as described above is reduced. Contrary to the predetermined threshold, it is possible to easily detect foreign matters (that is, a risk of damaging the upper surface of the substrate by the slit nozzle).

By the way, in the floatless coating method of the floating method, since the noise component caused by the shaking of the substrate due to the floating conveyance of the substrate or the vibration of the surroundings is mixed in the SN ratio near the output signal of the optical sensor, the light beam is shielded from light. By the technique of the prior art that contrasts the amount of light or the amount of received light reduction to a predetermined threshold, it is impossible to accurately extract (detect) the harmful back surface foreign matter (which may damage the upper surface of the substrate by the slit nozzle).

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, and it is possible to accurately and reliably detect harmful back foreign matters that may be damaged by rubbing an upper surface of a substrate to an elongated nozzle in a floating spinless coating method. Provided is a back foreign matter detection method, a back foreign matter detection device and a coating device using the same.

According to the method for detecting a foreign object on the back surface of the present invention, a nozzle having an elongated shape disposed above the floating area and conveying the substrate to be processed so as to pass through the floating area formed by mixing a plurality of jets and a plurality of suction ports at a predetermined floating height. A coating apparatus for supplying a processing liquid onto the substrate passing from below to form a coating film of the processing liquid, wherein the back surface foreign matter that is harmful to the long nozzle is attached to the rear surface of the substrate. A back foreign matter detection method for detecting at a position on the upstream side of the substrate conveyance direction rather than a nozzle, wherein the substrate passes through the floating region between the light transmitting portion and the light receiving portion disposed opposite to both sides with the floating stage interposed therebetween. A light beam traversing an upper surface and traversing horizontally is transmitted to indicate a light receiving amount of the light beam from the light receiving portion. Based on the first step of acquiring the received light quantity signal and the profile of the waveform of the light beam received amount being inverted on the time axis based on the received light quantity signal, a predetermined target is displayed in the waveform of the light beam received amount. When detecting the profile of the inversion type of the magnitude | size exceeding the reference size of, it has a 2nd process of generating the warning signal which detected the said harmful back surface foreign material.

The apparatus for detecting foreign objects on the back surface of the present invention conveys a substrate to be processed so as to pass through a floating area formed by mixing a plurality of ejection openings and a plurality of suction openings to a predetermined floating height, and has an elongated nozzle disposed above the floating area. A coating apparatus for supplying a processing liquid toward the substrate passing from below to forming a coating film of the processing liquid on the substrate, wherein the back surface foreign matter is harmful to the elongated nozzle by adhering to the rear surface of the substrate. A back surface foreign matter detection device for detecting a light at a position upstream of a substrate conveyance direction than the elongated nozzle, comprising: a light transmitting portion and a light receiving portion disposed opposite to both sides with the floating stage interposed therebetween, The light beam passing horizontally across the upper surface of the substrate passing therethrough is transmitted between the light transmitting portion and the light receiving portion ( Iii) a profile in which the waveform of the light beam received amount is inversely distributed on the time axis based on an optical sensor that outputs a received amount signal indicating the received amount of the light beam from the light receiving unit, and the received amount signal output from the light sensor Is a monitoring target, and has a signal processing unit for generating an alarm signal indicating that the harmful back surface foreign material has been detected when a profile of an inverted type having a size exceeding a predetermined reference size is detected in the waveform of the light beam received amount.

According to the back foreign matter detection method or the back foreign matter detection apparatus of the present invention, since the waveform of the light beam received amount obtained from the optical sensor is subjected to the inverted type profile on the time axis, it is not affected by the noise component included in the received amount signal. Therefore, it is possible to accurately determine whether or not the foreign material that is the cause of the inverted profile is a foreign material that is harmful to the nozzle of the elongated shape (that is, there is a risk of damaging the upper surface of the substrate by the nozzle of the elongated shape). .

An applicator according to the present invention conveys a floating stage having a first floating region formed by mixing a plurality of jets and a plurality of suction ports, and the substrate floating in the air on the floating stage to pass through the first floating region. A processing liquid supply unit having a conveying mechanism to be formed, an elongated nozzle disposed above the first floating region, and supplying a processing liquid from the elongated nozzle onto the substrate passing through the first floating region; The back foreign material of the present invention for attaching to the back surface of the substrate passing through the first floating region at the position upstream of the elongated nozzle in the substrate conveyance direction and detecting a harmful foreign matter with respect to the elongate nozzle. It has a detection device.

According to the back surface foreign matter detection method or the back surface foreign matter detection apparatus of the present invention, the harmful back surface which may be damaged by rubbing the upper surface of the substrate by the long nozzle in the floating-type spinless coating method by the configuration and action as described above. Foreign matter can be detected with good accuracy.

Further, according to the coating apparatus of the present invention, by providing the back surface detecting apparatus of the present invention, it is possible not only to reliably prevent the damage of the elongated nozzle, but also to avoid unnecessary interruption of the coating treatment operation due to the back surface foreign matter. Therefore, maintenance cost can be reduced and coating processing efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic plan view showing the main configuration of a resist coating apparatus to which the back foreign matter detection method or the back foreign matter detection apparatus of the present invention can be applied.
Fig. 2 is a front view schematically showing a coating operation operation in the resist coating apparatus.
FIG. 3 is a view for explaining a scene when the foreign matter becomes a problem in the resist coating apparatus. FIG.
FIG. 4 is a view for explaining a scene when the foreign matter becomes a problem in the resist coating apparatus.
5 is a view for explaining the operation of the back surface foreign matter detection device in the resist coating device.
6 is a block diagram showing the configuration of the back foreign matter detection apparatus according to the embodiment.
It is a side view which shows the arrangement structure of the optical sensor in the back foreign material detection apparatus of embodiment.
Fig. 8 is a partially enlarged front view showing the thickness increase of the substrate due to the foreign matter on the back and the action of the optical sensor.
9 is a diagram showing waveforms of light beam received amounts obtained by the optical sensor.
Fig. 10 is a diagram showing the action of the A / D converter in the back surface foreign matter detection device.
Fig. 11 is a block diagram showing the structure of an arithmetic unit in the signal processing unit of the back surface foreign matter detection device.
12 is a view for explaining the operation of the sample value extraction unit included in the calculation unit of the signal processing unit.
FIG. 13 is a view for explaining the operation of the decrease calculator and the adder included in the calculator.
14 is a view showing the operation (application example) of the signal processing unit.
15 is a block diagram showing a configuration of a signal processing unit in a modification.
Fig. 16 is a diagram showing the operation (application example) of the signal processing unit according to the modification.
It is explanatory drawing of the height positioning of a light beam.
18 is an explanatory view of the height positioning of the light beam.
19 is an explanatory diagram of a light receiving state of a light receiving unit of a light beam.

EMBODIMENT OF THE INVENTION Preferred embodiment of this invention is described below with reference to an accompanying drawing.

1, the main structure of the resist coating apparatus which can apply the back surface foreign material detection method or back surface foreign material detection apparatus of this invention is shown.

This resist coating apparatus adopts the floating type spinless coating method, and as shown in FIG. 1, the floating stage which floats the to-be-processed board | substrate, for example, glass substrate G for FPD in the air by gas pressure. (10), the conveyance mechanism 12 which conveys the board | substrate G floating in the air on this floating stage 10 to the floating stage longitudinal direction (X direction), and the board | substrate which conveys the floating stage 10 image ( The slit nozzle 14 which supplies a resist liquid to the upper surface of G) is provided.

The upper surface of the floating stage 10 is partitioned into three regions along the substrate conveyance direction (X direction), that is, the carry-in region M _IN , the application region M _COT, and the carry-out region M _OUT . Among these, many ejection openings 16 are formed in predetermined | prescribed density in the loading area | region _MIN and carrying out area | region M _OUT , and many injection nozzles 16 and the suction port 18 are mixed in predetermined | prescribed density in the application | coating area | region M _COT. It is formed.

The substrate to bring the give-and-take from the import region M _IN is, the substrate (G) before coating with pyeongryu (平流) carried by the external device of the front sorter mechanism (not shown), or a transport robot (not shown) An import unit (not shown) is provided. The board | substrate carrying out for carrying _out the application | coating-processed board | substrate G to carrying out of flat flow by the sorter mechanism (not shown) by the sorter mechanism (not shown), or sending and receiving to the transfer robot (not shown) to the export area M _OUT . A part (not shown) is installed.

In the application region M _COT , the slit nozzle 14 is provided to move upward and downward on the stage, and the nozzle refresh unit 24 which refreshes the slit nozzle 14 during the coating process is the substrate conveyance direction (X). It is installed so that horizontal movement is possible in parallel with the direction.

As shown in FIG. 1, the conveyance mechanism 12 reciprocates along a pair of guide rails 26A and 26B extending in the X direction with the floating stage 10 interposed therebetween, and these guide rails 26A and 26B. A pair of movable sliders 28 and a substrate holding member (not shown) such as a suction pad provided on the slider 28 to detachably hold both ends of the substrate G on the floating stage 10. By moving the slider 28 in the substrate conveyance direction (X direction) by a straight moving mechanism (not shown), the substrate is moved from the loading area M _IN to the unloading area M _OUT through the application area M _COT on the floating stage 10. It is comprised so that floating of (G) may be carried.

The slit nozzle 14 traverses the upper side of the floating stage 10 in the horizontal direction (Y direction) orthogonal to the substrate conveyance direction, and has a slit shape with respect to the upper surface (the to-be-processed surface) of the substrate G passing underneath it. The resist liquid R is discharged in a band shape from the discharge port of the filter. In addition, the slit nozzle 14 includes, for example, a ball screw mechanism, a guide member, etc. attached to the door-shaped frame 30 provided with the floating stage 10 in parallel with the slit nozzle 14 (in the Y direction). The nozzle lifting mechanism 36 included is configured to be movable (up and down) in the vertical direction (Z direction) integrally with the nozzle support member 38 for supporting the nozzle 14. In addition, the slit nozzle 14 is connected to the resist supply mechanism 40 (FIG. 2, FIG. 5) comprised with a resist liquid container, a liquid feed pump, etc. via the resist supply pipe 42. As shown in FIG.

Here, the resist coating operation | movement in this resist coating apparatus is demonstrated. First, a substrate (G) from the front end substrate processing apparatus (not shown) is imported into imported region M _IN injury stage 10 through the sorter mechanism or a transfer robot, the slider there was listened 28 is a substrate (G G) and receive. On the floating stage 10, the substrate G floats in the air by the pressure (lift) of the air injected from the jet hole 16.

In this way, when the board | substrate G is conveyed in the board | substrate conveyance direction (X direction) by the conveyance mechanism 12, floating up horizontally on the floating stage 10, and passes through the application | coating area | region M _COT of a stage center part, a slit nozzle The resist 14 discharges the resist liquid R in a band shape at a predetermined flow rate toward the substrate G so that the film thickness is uniform from the front end side to the rear end side of the substrate G as shown in FIG. 2. Coating film RM of liquid is formed.

When the rear end of the substrate G passes under the slit nozzle 14, a resist coating film RM is formed on one surface of the substrate. Subsequently, the board | substrate G is subsequently conveyed by the slider 28 on the floating stage 10, and is a unit of a rear end via a sorter mechanism or a conveying robot from the carrying out area M _OUT set at the rear end of the floating stage 10. FIG. Sent to (not city).

As shown in FIG. 2, the floating heights H _IN and H _OUT for carrying in and out of the carry-in area M _IN and the carry-out area M _OUT of the floating stage 10 do not require particularly high precision. What is necessary is just to hold | maintain in the range of 250-350 micrometers.

In contrast, the coating area M _COT of the floating stage 10 is a place where the resist liquid R is supplied from the upper slit nozzle 14 when the substrate G passes through it. FH H _COT in the coating region M _COT is, define a coating gap (K) (e.g. 100㎛) between the slit nozzle 14, the bottom (discharge port) and a substrate upper surface (front and back surfaces features) of.

This coating gap K is an important parameter that influences the film thickness and resist consumption of the resist coating surface RM, and needs to be kept constant with high precision. For this reason, in order to float the board | substrate G to a desired floating height H _COT , on the upper surface of the application | coating area | region M _COT , the blowing port 16 which blows out compressed air of high pressure or positive pressure, and the suction port 18 which inhales air by a negative pressure ) Are installed in combination (FIG. 1). Then, the vertical upward force by the high pressure air is applied from the jet port 16 to the portion passing through the coating area M _COT of the substrate G, and the vertical downward force is caused by the negative pressure suction force from the suction port 18. By controlling the balance of bidirectional forces that resist each other, the floating height H _COT in the coating area M _{COT is maintained} at a high precision around the set value (for example, 40 µm).

On the other hand, the size of the coating area M _COT in the substrate conveyance direction (X direction) should just be enough to be able to stably form the narrow coating gap K as mentioned above directly under the slit nozzle 14, Usually, it may be smaller than the size of the substrate G, for example, about 1/3 to 1/4.

Here, with reference to FIGS. 2-4, the scene which the foreign matter adhering to the back surface of the board | substrate G in this resist coating apparatus becomes a problem is demonstrated.

For example, a levitation stage 10, the foreign object (Q) on the back surface of a conveyed substrate (G) is attached to, the foreign object (Q) the size H _Q in the vertical direction brought region M _IN flying height H _IN of Consider a case lower than (250 to 350 mu m) and higher than the floating height H _COT (40 mu m) of the application area M _COT .

As it is shown in Fig. 2, when the foreign object (Q) is as long as the import region M _IN, the substrate (G) is any influence from the foreign object (Q) as it is also conveyed without being injured. However, as shown in FIG. 3, when this back surface foreign material Q enters the application | coating area | region M _COT , it will fit between the back surface of the board | substrate G and the top surface of the floating stage 10, and accordingly, the top surface of the board | substrate G will be The back surface is increased at the point G _Q to which the foreign matter Q is attached. The magnitude | size (rising part) of this increase part G _Q is corresponded to the difference H _Q -H _COT of the size H _Q of the height direction of the back surface foreign material _Q, and the floating height H _COT (40 micrometers). Therefore, when this difference H _Q -H _COT is the size more than application | coating gap K (100 micrometers), ie, when the size H _Q of the height direction of the back surface foreign material _Q is 140 micrometers or more, a back foreign material ( When Q) passes directly under the slit nozzle 14, the increased portion G _Q of the substrate G is rubbed over the discharge port of the slit nozzle 14 from above. As a result, the discharge port of the slit nozzle 14 is damaged, and the slit nozzle 14 cannot be used with a considerable probability.

In this embodiment, as shown in FIG. 5, by providing the back surface foreign matter detection apparatus 50 of this invention, as mentioned later, the above-mentioned harmful (namely, the upper surface of the board | substrate G in the slit nozzle 14). It is possible to reliably detect the foreign matter Q at the upstream side of the substrate conveyance direction (X direction) rather than the slit nozzle 14. Then, in response to the alarm signal WS generated when the back surface foreign matter detection device 50 detects such a harmful back surface foreign material Q, the main control part 52 passes through the nozzle elevating mechanism 36 to the slit nozzle 14. By immediately moving up), the slit nozzle 14 can move the increased portion G _Q of the substrate G out of the way (sliding contact or collision can be avoided), thereby preventing damage to the slit nozzle 14. do.

On the other hand, in response to the alarm signal WS, it is preferable that the main controller 52 controls the resist supply mechanism 40 to stop the resist discharge operation of the slit nozzle 14, and the transfer mechanism 12 May be controlled to stop the conveyance of the substrate G once.

In addition, in this embodiment, as will be described later, the harmless back surface foreign matter Q is substantially harmless (ie, there is no fear of rubbing the upper surface of the substrate G on the slit nozzle 14). As for the back surface foreign matter q, the back surface foreign matter detection device 50 does not generate the said alarm signal WS. As a result, the situation of unnecessarily interrupting the application processing operation being performed is avoided, and the fall of the apparatus operation rate due to the back surface foreign matter is avoided to the maximum.

5-16, the structure and operation | movement of the back surface foreign matter detection apparatus 50 in one Embodiment of this invention are demonstrated in detail.

As shown to FIG. 5 and FIG. 6, the back surface foreign matter detection apparatus 50 in this embodiment includes the optical sensor 54 arrange | positioned upstream of the slit nozzle 14 in a board | substrate conveyance direction (X direction), The signal processing part 56 which detects the harmful back surface foreign material Q adhering to the board | substrate G based on the light reception amount signal AS output from this optical sensor 54 by predetermined signal process is provided.

The optical sensor 54 has a light transmitting unit 58 and a light receiving unit 60. As shown in FIG. 5 and FIG. 7, the light transmitting part 58 and the light receiving part 60 provide a suitable distance (for example, 60 to 80 mm) from the slit nozzle 14 to the upstream side of the substrate conveyance direction (X direction). It is arranged so as to oppose both sides of the floating stage 10 (application area M _COT ).

Although one LD (semiconductor laser) may be sufficient as the light transmission part 58, Preferably, it consists of a two-dimensional LD array which arrange | positions many LD in the vertical-and-horizontal matrix shape, and the drive current from a light emission drive circuit (not shown) is carried out. When light is supplied, light is emitted and the light beam LB having a beam cross-sectional size of 1 mm in length and 5 mm in width is emitted, for example. At this time, the lower end portion of the light beam LB emitted from the light-transmitting portion 58 is disconnected from one side surface of the substrate G, so that only the beam portion which horizontally propagates a space higher than the upper surface of the substrate G is present. You may set or adjust the height position of a beam optical path so that the light receiving surface of this light receiving part 60 may be reached.

The light receiving unit 60 is composed of a two-dimensional CCD (Charge-Coupled Device) formed by arranging a plurality of light receiving cells in a vertical and horizontal matrix shape in all light receiving regions of a predetermined size (e.g., 1 mm long and 5 mm wide), and have a constant cycle. In the period of, photoelectric conversion of the received light for each light receiving cell is performed to generate a signal charge or an analog light receiving amount signal AS indicating the light receiving amount AE, and the light receiving amount signal AS is continuously converted in time series by a predetermined transmission method. To output

As shown in FIG. 8, when the harmful back surface foreign material Q (or harmless back surface foreign material q) passes through the optical sensor 54, by the increase part G _Q (G _q ) of the board | substrate G. The light-shielding portion of the light beam LB increases, that is, the light-receiving amount of the light beam LB in the light-receiving unit 60 decreases, and the waveform of the light-receiving amount AE is shown in FIG. A profile AE _Q (AE _q ) of the mortar shape is shown.

In FIG. 6, the signal processing unit 56 has an analog-to-digital (A / D) converter 62, a light receiving amount data memory 64, an arithmetic processing unit 66, a setting unit 68, and an output unit 70. have. Among these, the light-receiving amount data memory 64, the arithmetic processing part 66, the setting part 68, and the output part 70 are comprised by a microcomputer, for example.

As illustrated in FIG. 10, the A / D converter 62 converts the received light amount signal AS from the optical sensor 54 (light receiving unit 60) at a predetermined period Δt (for example, 1.5 msec), Namely, the received light amount data is converted into A0, A1, A2, .... The light reception amount data memory 64 temporarily stores the light reception amount data? A0, A1, A2, ... outputted from the A / D converter 62 in an overwrite manner by a minute (a certain amount of data) up to a certain time from the present time. .

As shown in FIG. 11, the calculation unit 66 includes a sample value extraction unit 72, a decrease calculation unit 74, an integration unit 76, and a determination unit 78.

12, the operation of the sample value extracting unit 72 will be described. In the drawings, [1], [2], [3], and [4] represent extraction points. The sample value extracting unit 72 includes a plurality (n), for example, four light receiving amount data Ai-3p, of a predetermined time interval (p * Δt), among the light receiving amount data stored in the light receiving amount data memory 64. Ai-2p, Ai-p, Ai) is extracted. For example, if p = 10, immediately after the received light amount data A30 is stored in the received light amount data memory 64, the sample value extracting unit 72 will receive the received light amount data A30 and ten (10Δt minutes) ahead of it. The light-receiving amount data A20, the light-receiving amount data A10 for ten (10Δt minutes) earlier than that, and the light-receiving amount data A0 for ten (10Δt minutes) earlier than that are simultaneously extracted.

Then, if the next received light amount data A31 of the received light amount data A30 is stored in the received light amount data memory 64, immediately after that, the sample value extracting unit 72 performs the four received light amount data at intervals of a predetermined time (10? T minutes) in the same manner as described above. (A1, A11, A21, A31) are extracted. Then, when the received light amount data A32 of the received light amount data A31 is stored in the light received amount data memory 64, immediately after that, the sample value extracting unit 72 also receives four light received amounts at intervals of a predetermined time (10Δt minutes) in the same manner as described above. Data A2, A12, A22, and A32 are extracted.

On the other hand, the number n (preferably 3 or more) of the extraction points used by the sample value extraction part 72 and the space | interval p are given from the determination part 68 (FIG. 6).

13, the operation of the decrease calculator 74 will be described. The decrease calculating unit 74 receives light receiving amount decreases δi-3p and δi-2p for the four light receiving amount data Ai-3p, Ai-2p, Ai-p, Ai extracted by the sample value extracting unit 72, respectively. , δi-p, δi) is obtained. Here, delta i-3p = N-Ai-3p, delta i-2p = N-Ai-2p, delta i-p = Ai-p, delta i = N _AE -Ai, and N _AE is a light receiving amount reference value. Therefore, for example, the received light amount reductions (δ0, δ10, δ20, δ30) obtained at time t30 are δ0 = N _AE -A0, δ10 = N _AE -A10, δ20 = N _AE -A20, δ30 = N _AE -A30 .

The light receiving amount reference value N _AE is preferably a value of the light beam light receiving amount obtained from the light receiving unit 60 when the first portion of the substrate G passes through the optical sensor 54 in the substrate conveyance direction (X direction), or The value of the light beam received amount obtained by the light receiving unit 60 at a predetermined time (for example, 10 msec) before the most temporally older one of the four extraction points [1], [2], [3], and [4]. Is set to a value of 100%.

The decrease calculation unit 74 normalizes the light receiving amount data A2, A12, A22, and A32 to% display, and obtains the light receiving amount decreasing amounts δ0, δ10, δ20, and δ30 by% display. Thus, for example, when (A2, A12, A22, A32) = (100, 98, 95, 97), (δ0, δ10, δ20, δ30) = (0, 2, 5, 3).

The integrating unit 76 multiplies the four light receiving amount reductions δi-3p, δi-2p, δi-p, δi outputted collectively or in one frame (FL) from the decrease calculating unit 74 (乘). V) and outputs the calculation result Ii. For example, when (δ0, δ10, δ20, δ30) output from the decrement calculating unit 74 is (0, 2, 5, 3), a multiplication of 0 * 2 * 5 * 3 is made, and as a result of the calculation , Ii = 0 is output.

The determination unit 78 compares the calculation result I _i output from the integration unit 76 with the determination threshold I _s from the setting unit 68 (FIG. 6), and determines their magnitude relationship, and I _i ≤ I _{At s} , the determination output signal W is, for example, a logic value L. At I _i > I _s , the determination output signal W is, for example, a logic value H. When the determination output signal W of the logic value H is output from the determination unit 78, the alarm signal WS is output from the output unit 70 (FIG. 6).

As described above, in the signal processing unit 56, the sample value extraction unit 72 and the decrease calculation unit 74, for example, set a plurality (n) of predetermined intervals (p * Δt) on the time axis. For example, at the four extraction points [1], [2], [3], and [4], the decreases (δi-3p, δi-2p, δi-p,) of the light beam received amount (AE) with respect to the predetermined light receiving amount reference value N _AE A first operation to find delta i) is performed. The amount of received light reductions (δi-3p, δi-2p, δi-p, δi) obtained by the integration unit 76 from the plurality of extraction points [1], [2], [3], and [4], respectively. A second operation of multiplying is performed. Finally, the plate in the state 78, the integrated value I _i of the received light intensity decrease as compared to a predetermined threshold value I _S, integrated value I _i is time exceeds the threshold value I _S, outputs the determination result of the logical value H W A third operation is made.

Here, the determination unit 78 outputs the determination result W of the logic value H. In this case, the foreign material detecting device 50 has an inverted profile whose magnitude exceeds the reference size in the waveform of the light beam received amount AE. It means that it is determined to be included.

Here, the time width T _S from the beginning [1] to the end [4] of the extraction points [1], [2], [3], and [4], and the threshold value I _s are the heights of the harmful foreign matter Q. Reference size (diameter size D _Q , received amount decrease peak value δ _Q of the inverted profile, which appears in the waveform of the received light amount AE when the size H _Q in the direction is a lower limit (that is, the sum of the floating height H _COT and the coating gap K). ) Is set to an optimal or appropriate value.

For example, the thickness T _G of the substrate (G) 700㎛, the flying height H _COT 40㎛, the coating gap (K) is the case of 100㎛, if the size H in the vertical direction _Q is 140㎛ harmful foreign substances (Q ) Is attached to the rear surface of the substrate G, the increase portion G _Q of the substrate G becomes the height of the discharge port of the slit nozzle 14. At this time, the diameter size of the inverted profile shown in the waveform of the light receiving amount AE is 70 μm, and the light receiving amount decreasing peak value δ _Q is 7%. These values (70 micrometers, 7%) are obtained by experiment.

On the other hand, since the substrate conveyance speed v is constant, the time axis t in the waveform of the received light amount signal AS or the received light amount AE can be replaced by the X axis in the substrate conveyance direction in a constant proportional relationship (X = vt).

Therefore, in theory, most harmful back surface foreign substances Q can be detected, for example, when facing the threshold of 5%-7%. However, in reality, the received light amount signal AS output from the optical sensor 54 is mostly mixed with a noise component at an SN ratio close to 1 due to shaking of the substrate G in the floating conveyance or vibration of the optical sensor 54 itself. Therefore, such a judgment method is not valid.

Thus, in this embodiment, the amount of light received decreases δi-3p and δi− of one frame FL obtained from the plurality of n extraction points [1], [2], [3], and [4] as described above, respectively. 2p, delta i-p, delta i) are multiplied (or added), and the size of the inverse type profile is calculated based on the calculation result (integrated value) I _i .

In this method, the total time width T _s of the extraction point is suitably smaller (preferably 1 / 2D _Q <DT _S <D _Q ) than the diameter size D _Q (70 μm) of the reference (lower limit) in terms of distance DT _S. Important, for example, DT _S = 60 μm. Accordingly, it is possible to determine that the diameter size is smaller than DT _s among the inverted profile, so that the integrated value I _i always takes a value of zero or its vicinity, so that it is not the foreign matter Q if it is harmful. In addition, among the inverted profile, the diameter size is larger than T _S , so that the size of the inverted profile is reflected in the integrated value I _i , so that the threshold value I _s of the appropriate value reliably discriminates the foreign material Q if it is harmful. can do.

For example, when the minimum harmful back surface foreign material _Q whose size H _Q of the height direction is 140 micrometers is affixed to the back surface of the board | substrate G as mentioned above, FIG.14 (a) shows the waveform of the light reception amount AE. When the inverse profile as shown in Fig. 7 appears, the integrated value I _i is 1 * 4.5 * 6 * 2.5 = 67.5. The integrated value I _i is an attribute value inherent to the inverse profile, which is hardly influenced by the noise component. Therefore, by setting the threshold value I _s to, for example, 60, it is possible to accurately and surely determine that the back surface foreign material is a harmful back surface foreign material Q.

In addition, when the harmful back surface foreign material _Q whose size H _Q of the height direction is 190 micrometers is affixed on the back surface of the board | substrate G, the waveform of the light reception amount AE is shown in FIG. 14 (b). The profile appears. In this case, the integrated value I _i is in 8.5 * 9 * 5 * 2 = 675, was much more than the threshold value I _S (60), can also be reliably determined to be harmful if the foreign object (Q).

In addition, in the case where the substantially harmless back surface foreign material q having a size H _Q in the height direction is attached to the back surface of the substrate G, the waveform of the received light amount AE is inverted as shown in Fig. 14C. Type profile appears. In this case, the integrated value I _i is 0 * 1 * 3 * 0.2 = 0, and it can be clearly determined that this foreign material is not a foreign material Q if it is a harmful object.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation or a change are possible within the range of the technical idea.

For example, as shown in FIG. 15, the calculating part 66 of the signal processing part 56 can be comprised by the sample value extraction part 72, the pattern comparison part 80, and the determination part 82. As shown in FIG. Here, as shown in FIG. 16, the pattern comparison unit 80 has an inversion having a reference size (reference diameter size D _Q , reference light reception decrease peak value δ _Q ) or a smaller size than that on the waveform of the light beam light reception amount on the time axis. Reduction of the amount of received light of the inverse type profile (δi-4p, δi-3p, δi-2p, δi-p) with the model pattern MP of the type profile as a normal and plural places (for example, 5 places) [1] to [5]. , δ i) and the model pattern MP are compared, and the magnitude relationship is output as two values of +/-. In addition, data of the model pattern MP is given from the setting unit 68 (Fig. 6).

For example, when the smallest harmful back surface foreign material _Q whose size H _Q of the height direction is 140 micrometers is affixed to the back surface of the board | substrate G, it will become like FIG.16 (a), and compares [1]- In all of [5], the decrease in the amount of received light (δi-4p, δi-3p, δi-2p, δi-p, δi) of the inverse profile was greater than the model pattern MP, so that the (+, + A comparison result of (+, +, +) yields an output. In this case, since the comparison result outputs are all +, the determination part 82 outputs the determination result W of the logic value H that the foreign material Q was detected if it was harmful.

In addition, when the harmful back surface foreign material _Q whose size H _Q of the height direction is 190 micrometers is affixed on the back surface of the board | substrate G, it becomes like FIG.16 (b), and also compares [1]-[ 5], the reduction in the amount of received light (δi-4p, δi-3p, δi-2p, δi-p, δi) of the inverted profile exceeds the model pattern MP, so that from the pattern comparison section 80, (+, +, The comparison result output of +, +, + is obtained, and the determination part 82 outputs the determination result W of the logic value H that the foreign material Q was detected if it was harmful.

However, in the case where the foreign matter q having a substantially harmless back surface q having a size H _Q in the height direction is adhered to the back surface of the substrate G is as shown in Fig. 16C, the comparison points [4] and [ 5, the received amount decrease of the inverted profile (δi-4p, δi-3p) is higher than the model pattern MP, but in the comparison points [1], [2], [3], the received amount decreased in the inverted profile (δi-2p) , δ i -P, δ i) are below the model pattern MP. In this case, the comparison result output of (+, +,-,-,-) is obtained from the pattern comparison part 80. FIG. Thereby, since the part of the comparison result output is "-", the determination part 82 outputs the determination result W of the logic value L which is not the foreign material Q when it is harmful.

On the other hand, the lower end portion of the light beam LB emitted from the light transmitting portion 58 is disconnected from one side surface of the substrate G, so that only the beam portion that horizontally propagates the space higher than the upper surface of the substrate G receives the light receiving portion ( Although the height position of the beam optical path may be set or adjusted so as to reach the light receiving surface at 60), the reason will be described next.

As setting of the height position of the optical path of the light beam LB, the following three things can be considered. First, as shown in FIG. 17, the case where it sets so that the upper surface of the board | substrate G and the lower end of the light beam LB may correspond may be set. In this case, for example, when the substrate G even sinks even a little, a gap is formed between the upper surface of the substrate G and the lower end of the light beam LB, so that foreign substances on the harmful surface of the substrate G can be detected with high accuracy. Since it may not be possible, it is not preferable as a setting.

Second, as shown in FIG. 18, when the board | substrate G is arrange | positioned in the light beam LB, ie, the side surface of the board | substrate G is arrange | positioned all in the light beam LB. In this case, the light beam LB also passes between the lower surface of the substrate and the floating stage 10. A light receiving state of the light receiving unit 60 will be described with reference to FIG. 19. The light receiving unit 60 detects at two values (white and black). The bag is a region where the light beam LB has reached, and the areas are set to S1 and S2. Black is an area | region where the light beam LB was not able to receive. Moreover, (DELTA) S is an area | region where the foreign material was pinched | interposed between the back surface (lower surface) of the board | substrate and the floating stage 10, the surface (upper surface) of the board | substrate G became thick, and the light beam LB was not able to receive. Let ΔS be. The light receiving part 60 sends the detection result of the light beam LB to the calculating part 66, and calculates following Formula using area S1, S2, (DELTA) S.

R (%) = {(S1 + S2-ΔS) / (S1 + S2)} × 100... ①

For simplicity and simplicity, the foreign material detection on the back surface of the substrate is performed using the above R value. Since the light beam LB exists between the lower surface of the substrate and the floating stage 10, for example, the foreign material on the back surface of the substrate is present. Even in this case, since the change in the R value becomes small, it is not preferable as the setting of the light beam LB.

Third, as shown in FIG. 7, as described above, the lower end of the light beam LB cuts off from one side of the substrate G, and the beam propagates horizontally through the space higher than the upper surface of the substrate G. It is a case where only a part is set to reach the light receiving surface of the light receiving part 60. In this case, it is the most preferable setting because the calculated value of the above equation (1) is very different due to a slight change in ΔS.

In addition, in embodiment mentioned above, it demonstrated using the slit nozzle 14. As shown in FIG. However, instead of the slit nozzle 14 having the slit for discharging the coating liquid on the lower surface of the nozzle, for example, a long nozzle having a plurality of fine discharge holes formed on the lower surface of the nozzle may be used. Can be obtained.

As the processing liquid in the coating apparatus of the present invention, in addition to the resist liquid, for example, a coating liquid such as an interlayer insulating material, a dielectric material, a wiring material, and the like can be used, and various chemical liquids, a developing solution, a rinse liquid, and the like are also possible. The substrate to be treated in the present invention is not limited to an LCD substrate, and other flat panel display substrates, semiconductor wafers, CD substrates, photomasks, printed substrates, and the like can also be used.

The back foreign matter detection method and the back foreign matter detection device of the present invention can be suitably applied to a coating apparatus of a flat flow method, but can also be applied to other types of substrate processing apparatuses employing a flat flow method.

10: injury stage
12: conveying mechanism
14: slit nozzle
16: spout
18: suction port
40: resist supply mechanism
50: back side foreign matter detection device
52: light sensor
54: signal processing unit

Claims (30)

The substrate to be processed is conveyed so as to pass through the floating region provided with a plurality of ejection openings and a plurality of suction openings at a predetermined floating height, and passes therethrough from an elongated nozzle disposed above the floating region. A coating apparatus for supplying a processing liquid onto the substrate to form a coating film of the processing liquid, wherein the back surface foreign matter that is harmful to the long nozzle by being attached to the back surface of the substrate is formed in the long shape. As a back foreign matter detection method for detecting at a position on the upstream side of the substrate conveyance direction from a nozzle,
A light beam passing horizontally across the upper surface of the substrate passing through the floating region is transmitted between a light transmitting portion and a light receiving portion disposed opposite to both sides with the floating stage interposed therebetween. (Iii) a first step of acquiring a light receiving amount signal indicating a light receiving amount of the light beam from the light receiving unit;
Based on the light reception amount signal, a profile whose waveform of the light beam light reception amount is inverted on the time axis is monitored, and an inversion of a magnitude exceeding a predetermined reference size in the waveform of the light beam light reception amount And a second step of generating an alarm signal indicating that the harmful back surface foreign material has been detected when the mold profile is detected. The method of claim 1,
The said reference size is a back foreign matter detection method containing the peak value of the light reception amount of a reference | standard in a height direction, and the diameter size of the reference | standard in a horizontal direction. The method of claim 2,
The light receiving amount reduction peak value of the reference and the diameter size of the reference are set based on the experimental value, depending on the thickness of the substrate, the floating height and the coating gap between the elongated nozzle and the substrate. The method of claim 1,
The back surface foreign material detection method which sets the lower limit of the magnitude | size of the height direction as the said harmful back surface foreign material based on the value which added the said floating height and the said coating gap. The method of claim 1,
The second step,
A third step of obtaining a decrease of the light beam received amount with respect to a predetermined light received amount reference value at a plurality of extraction points set at predetermined intervals on a time axis;
A fourth step of integrating the received amount of light reduction respectively obtained from the plurality of extraction points;
A fifth step of comparing the integrated value of the received light amount reduction with a predetermined threshold and determining that an inverted profile of a size exceeding the reference size is included in the waveform of the light beam received amount when the integrated value exceeds the threshold; Back foreign matter detection method comprising. The method of claim 5,
The foreign material detecting method for back surface foreign matter in which the decrease of the light beam received amount is calculated by a percentage display in the third step, and the integration of the reduced light received amount is multiplied in the fourth step. The method according to claim 5 or 6,
And the light receiving amount reference value is a value of the light beam light receiving amount obtained by the light receiving portion when the head portion of the substrate has passed through the light transmitting portion and the light receiving portion in the substrate conveyance direction. The method according to claim 5 or 6,
And the light receiving amount reference value is a value of the light beam light receiving amount obtained by the light receiving unit a predetermined time before the oldest time in the plurality of extraction points. The method according to claim 5 or 6,
And a time width from the beginning to the end of the plurality of extraction points is smaller than the diameter size of the reference and larger than half of the diameter size of the reference. The method according to claim 5 or 6,
A back foreign matter detection method for forming three or more of the plurality of extraction points. The method according to any one of claims 1 to 6,
In the second step, a model pattern of an inverted profile having a reference size or a size smaller than that of the waveform of the light beam received amount on a time axis is defined as a regular value, and the magnitude exceeds the model pattern in a plurality of places. If an inversion profile of is found, it is determined that it is an inversion profile of a size exceeding the reference size. The substrate to be processed is passed through a floating area formed by mixing a plurality of ejection openings and a plurality of suction openings to a predetermined floating height, and the substrate passing below the elongated nozzle disposed above the floating area. A coating apparatus for supplying a processing liquid toward the substrate to form a coating film of the processing liquid on the substrate, wherein the back surface foreign matter that is attached to the rear surface of the substrate and is harmful to the elongated nozzle is conveyed to the substrate rather than the elongated nozzle. A back foreign matter detection device for detecting at a position on the upstream side in a direction,
It has a light transmitting portion and a light receiving portion disposed opposite to both sides with the floating stage therebetween,
An optical sensor that transmits a light beam that crosses the upper surface of the substrate passing through the floating region and crosses horizontally between the light transmitting portion and the light receiving portion, and outputs a light receiving amount signal indicating a light receiving amount of the light beam from the light receiving portion Wow,
Based on the received light quantity signal output from the optical sensor, a profile whose waveform of the light beam received amount is inverted on the time axis is monitored, and an inverted type having a size exceeding a predetermined reference size in the waveform of the light beam received amount The back surface foreign matter detection device which has a signal processing part which generate | occur | produces the alarm signal that the said harmful back surface foreign material was detected when a profile was detected. The method of claim 12,
And the reference size includes a reference light receiving amount decrease peak value in the height direction and a reference diameter size in the lateral direction. The method of claim 13,
The signal processing unit is a back surface foreign material using the reference light receiving amount reduction peak value and the diameter size of the reference set based on an experimental value depending on the thickness of the substrate, the floating height, and the coating gap between the elongated nozzle and the substrate. Detection device. The method of claim 12,
The back surface foreign matter detection apparatus which sets the lower limit of the height direction size as the said harmful back surface foreign material based on the value which added the said floating height and the said coating gap. The method of claim 12,
The signal processing unit,
A first calculating unit for obtaining a decrease of the light beam received amount with respect to a predetermined light received amount reference value at a plurality of extraction points set at predetermined intervals on a time axis;
A second calculating unit for integrating the received amount of light reduction respectively obtained from the plurality of extraction points;
A third calculation unit for comparing the integrated value of the received amount of light reduction with a predetermined threshold and determining that an inverted profile of a size exceeding the reference size is included in the waveform of the light beam received amount when the integrated value exceeds the threshold; Back foreign matter detection device comprising. The method of claim 16,
And said first calculating section obtains the decrease of said light beam received amount as a percentage display, and said second calculating section multiplies the integration of said reduced amount of received light by multiplication. The method according to claim 16 or 17,
The light receiving amount reference value is a back surface foreign matter detection device that is a value of a light beam light receiving amount obtained at the light receiving portion when the head portion of the substrate passes through the light transmitting portion and the light receiving portion in the substrate conveyance direction. The method according to claim 16 or 17,
And the light receiving amount reference value is a value of a light beam light receiving amount obtained by the light receiving unit a predetermined time before the oldest time in the plurality of extraction points. The method according to claim 16 or 17,
And a time width from the beginning to the end of the plurality of extraction points is smaller than the diameter size of the reference and larger than half of the diameter size of the reference. The method according to claim 16 or 17,
A back surface foreign matter detection device for forming three or more of said plurality of extraction points. The method according to any one of claims 12 to 15,
The signal processing unit normalizes the model pattern of the inversion type profile having the reference size or a smaller size to the waveform of the light beam received amount on the time axis as a normal, and the inverse type profile having a size exceeding the model pattern in a plurality of places is normalized. If found, it has a computing part for determining that it is an inverse profile of a size exceeding the reference size. A floating stage having a first floating area formed by mixing a plurality of jets and a plurality of suction holes,
A conveying mechanism for holding the substrate floating in the air on the floating stage to pass the first floating region;
A processing liquid supply part having an elongated nozzle disposed above the first floating area, and supplying a processing liquid from the elongated nozzle onto the substrate passing through the first floating area;
Claim 12 to Claim 12 for attaching to the back surface of the said board | substrate which passes through a said 1st floating area | region at the position of an upstream rather than the said elongate nozzle in a board | substrate conveyance direction, and detecting a harmful back surface foreign material with respect to the said elongate nozzle. The coating apparatus which has a back surface foreign matter detection apparatus in any one of Claims 17. The method of claim 23, wherein
And an elevating mechanism for elevating and moving the elongated nozzle, wherein the elongated nozzle is moved up and down through the elevating mechanism in response to the alarm signal generated from the back surface foreign matter detecting device. The method of claim 23 or 24,
And a coating apparatus discharging operation from the processing liquid supply unit in response to the alarm signal generated from the back surface foreign matter detecting device. The method of claim 23 or 24,
An application device for stopping a substrate conveyance operation in the conveyance mechanism in response to the alarm signal generated from the back surface foreign matter detection device. The method of claim 23 or 24,
And said floating stage has a second floating region in which a plurality of ejection openings for floating said substrate are formed on an upstream side of said first floating region in the substrate conveying direction. The method of claim 27,
A coating apparatus is provided in the second floating region, the carrying-in portion for carrying in the substrate. The method of claim 23 or 24,
And said floating stage has a third floating region in which a plurality of ejection openings for floating said substrate are formed on the downstream side of said first floating region in the substrate conveyance direction. The method of claim 29,
A coating apparatus is provided in the said 3rd floating area | region for carrying out the said board | substrate for carrying out the said board | substrate.

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