JP5108909B2 - Backside foreign matter detection method, backside foreign matter detection device, and coating device - Google Patents

Description

  The present invention relates to a coating apparatus that applies a processing liquid to a substrate to be processed on a floating stage, and more particularly, to a backside foreign matter detection method and a backside foreign matter detection device for detecting undesirable foreign matter adhering to the backside of a substrate.

  In a photolithography process in a manufacturing process of a flat panel display (FPD) such as an LCD, a resist solution is applied onto a substrate to be processed (such as a glass substrate) using a long slit nozzle having a slit-like discharge port. A spinless coating method is often used.

  As one form of such a spinless coating method, a substrate floating mechanism is incorporated in the stage for supporting the substrate, and the substrate is floated in the air on this floating stage and conveyed in one horizontal direction (stage longitudinal direction). There is a levitation method in which the resist solution is applied from one end to the other end on the substrate by discharging the resist solution in a strip shape toward the substrate that passes directly below the slit nozzle installed above the stage at a predetermined position in the middle. Are known.

  In such a levitation-type spinless coating method, in order to uniformly form a resist solution coating film on a substrate with a set film thickness, a small gap of usually about 100 μm provided between the discharge port of the slit nozzle and the substrate is used. Is accurately maintained at or near the setpoint.

  In order to satisfy this requirement, a resist coating apparatus that employs a levitation-type spinless coating method simply provides a large number of jet nozzles for jetting high-pressure or positive-pressure gas, such as air, at a predetermined density over substantially the entire surface of the levitation stage. Rather, a suction port for sucking air at a negative pressure is mixed in the ejection port in the application region set as the area immediately below and before and behind the slit nozzle on the floating stage. In the application region, the floating pressure applied to the substrate is finely balanced by balancing the vertical upward pressure applied from the jet port and the vertical downward pressure applied from the suction port with respect to the substrate passing therethrough. The flying height of the substrate is adjusted to a set value (usually 50 μm or less) (for example, Patent Document 1).

JP2007-190483A

  In the above-described spin-less spin coating method, as with other spinless coating methods, foreign matter may adhere to the substrate immediately before being subjected to the coating process, and foreign matter may be present at the tip (discharge port) of the slit nozzle. Or, when the upper surface of the substrate is rubbed, the slit nozzle may be damaged. If even a slight damage is made to the discharge port of the slit nozzle, the belt-like discharge flow becomes non-uniform, which directly leads to the deterioration of the film quality of the coating film. Since the slit nozzle is very expensive and it is not possible to easily replace the parts at a low cost, early detection of foreign matters adhering to the substrate is an important issue.

  There are two types of foreign matter on the substrate: front foreign matter that adheres to the front surface (upper surface) of the substrate and back foreign matter that adheres to the rear surface (lower surface) of the substrate. Among these, the surface foreign matter is harmful from the size of the light beam that is blocked or reduced by using the optical sensor that crosses the light beam so as to give up the upper surface of the substrate (that is, by directly rubbing the slit nozzle). It can easily detect foreign objects that may cause scratches. Therefore, it can be handled by a conventional foreign object detection device.

  However, the backside foreign matter is troublesome in the floating spinless coating method. In other words, if the spinless coating method uses a substrate placed on a stage and is fixed by suction, the rise of the substrate due to the foreign material on the back surface is regarded as a foreign material on the surface, and the light beam is blocked or the received light amount is reduced as described above. Can be easily detected for harmful foreign matters (that is, there is a possibility of scratching the slit nozzle by rubbing the upper surface of the substrate).

  However, in the spinless coating method of the floating system, noise components due to the shaking of the substrate due to the floating transportation of the substrate and the surrounding vibration are mixed in the output signal of the optical sensor with an S / N ratio close to 1, so Accurate extraction (detection) of harmful backside foreign matter (which may cause scratches by rubbing the top surface of the substrate against the slit nozzle), depending on the prior art technique of reducing the amount of received light to a predetermined threshold I can't.

  The present invention solves the above-described problems of the prior art, and accurately removes harmful backside foreign matters that may be scratched by rubbing the top surface of the substrate against the slit nozzle in the floating spinless coating method. Provided are a backside foreign matter detection method, a backside foreign matter detection device, and a coating apparatus using the backside foreign matter detection method capable of reliably detecting.

The first back surface foreign matter detection method that put the aspect of the present invention is to be processed to pass through the floating region of the floating stage in which a number of ejection ports and a plurality of suction ports arranged in a mixed manner at a predetermined floating height In a coating apparatus for transporting a substrate and supplying a processing liquid onto the substrate passing below a slit nozzle disposed above the floating region to form a coating film of the processing liquid, on the back surface of the substrate A backside foreign matter detection method for detecting a backside foreign matter that is attached and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, on both sides of the levitation stage Between the light projecting unit and the light receiving unit disposed to face each other, a light beam horizontally passing across the upper surface of the substrate passing through the floating region is transmitted and received, and the light beam is received from the light receiving unit. Receiving quantity A first step of obtaining a quantity signal, on the basis of the received light amount signal, a profile waveform of the light receiving amount of the light beam is inverted chevron on the time axis to be monitored, the light receiving amount of the waveform of the light beam upon detecting a magnitude inverted chevron profile that exceeds a predetermined reference size in, it has a second step of generating an alarm signal indicative of the detection of the harmful backside foreign matter, the reference size, The reference light reception amount decrease peak value in the height direction and the reference diameter size in the horizontal direction are included.
The backside foreign matter detection apparatus according to the first aspect of the present invention provides a substrate to be processed so as to pass at a predetermined flying height through a floating region of a floating stage provided with a large number of ejection ports and a large number of suction ports. In a coating apparatus for transporting and supplying a processing liquid toward the substrate passing under a slit nozzle disposed above the floating region, and forming a coating film of the processing liquid on the substrate, A backside foreign matter detection device for detecting a backside foreign matter adhering to the backside of a substrate and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, sandwiching the floating stage And having a light projecting portion and a light receiving portion arranged to face both sides of the light projecting portion and the light receiving portion. Sent and received between The light sensor outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit, and the received light amount waveform of the light beam is a time axis based on the received light amount signal output from the light sensor. The above-mentioned profile having an inverted chevron is monitored, and when the inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform of the received light amount of the light beam, the harmful backside foreign matter is detected. The reference size includes a reference received light amount decrease peak value in the height direction and a reference diameter size in the horizontal direction.
The Oite the back surface foreign substance detecting method or backside foreign matter detecting device of the first aspect, the profile received light amount of the waveform of the light beams obtained from the optical sensor is inverted chevron on the time axis to be monitored, the light beam It is detrimental when detecting an inverted chevron profile with a size exceeding the specified reference size including the reference received light amount decrease peak value in the height direction and the reference diameter size in the horizontal direction in the received light amount waveform. An alarm signal indicating that a foreign object on the back surface has been detected is generated. As a result, the backside foreign material that is the basis of the inverted chevron profile is harmful to the slit nozzle without being affected by the noise component included in the received light amount signal (that is, the upper surface of the substrate is rubbed against the slit nozzle). It is possible to accurately determine whether or not the foreign object is likely to be damaged.

According to a second aspect of the present invention, there is provided a backside foreign object detection method in which a substrate to be processed is passed at a predetermined flying height through a floating area of a floating stage provided with a large number of jet outlets and a large number of suction ports. In a coating apparatus that forms a coating film of the processing liquid by supplying a processing liquid onto the substrate that is transported and passes below a slit nozzle that is disposed above the floating region, and adheres to the back surface of the substrate. A foreign matter detection method for detecting a foreign matter that is harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, facing both sides of the levitation stage. Between the light projecting unit and the light receiving unit arranged in a horizontal direction, the light beam horizontally passing across the upper surface of the substrate passing through the floating region is transmitted and received, and the amount of light beam received from the light receiving unit is Receiving A first step of acquiring a quantity signal, and a profile of the light receiving quantity of the light beam, which is an inverted mountain shape on the time axis, based on the received light quantity signal, and monitoring the received light quantity waveform of the light beam A second step of generating an alarm signal indicating that the harmful backside foreign object has been detected when an inverted chevron profile having a size exceeding a predetermined reference size is detected, and the flying height and the The lower limit value of the size in the height direction as the harmful backside foreign matter is set on the basis of a value obtained by adding the application gap between the slit nozzle and the substrate.
The backside foreign object detection device according to the second aspect of the present invention provides a substrate to be processed so as to pass through a floating region of a floating stage provided with a large number of jet ports and a large number of suction ports at a predetermined flying height. In a coating apparatus for transporting and supplying a processing liquid toward the substrate passing under a slit nozzle disposed above the floating region, and forming a coating film of the processing liquid on the substrate, A backside foreign matter detection device for detecting a backside foreign matter adhering to the backside of a substrate and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, sandwiching the floating stage And having a light projecting portion and a light receiving portion arranged to face both sides of the light projecting portion and the light receiving portion. Sent and received between The light sensor outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit, and the received light amount waveform of the light beam is a time axis based on the received light amount signal output from the light sensor. The above-mentioned profile having an inverted chevron is monitored, and when the inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform of the received light amount of the light beam, the harmful backside foreign matter is detected. A signal processing unit that generates an alarm signal, and the height as the harmful backside foreign matter on the basis of a value obtained by adding the flying height and the coating gap between the slit nozzle and the substrate. The lower limit value of the direction size is set.
In the backside foreign object detection method or backside foreign object detection device according to the second aspect, a profile in which the waveform of the light reception amount of the light beam obtained from the optical sensor is inverted on the time axis is monitored, and the amount of light reception of the beam is monitored. When an inverted chevron profile having a size exceeding a predetermined reference size is detected in the waveform, an alarm signal indicating that a harmful backside foreign object has been detected is generated. Here, the lower limit of the size in the height direction as a harmful backside foreign material is set based on a value obtained by adding the flying height of the substrate on the flying stage and the coating gap. As a result, the backside foreign material that is the basis of the inverted chevron profile is harmful to the slit nozzle without being affected by the noise component included in the received light amount signal (that is, the upper surface of the substrate is rubbed against the slit nozzle). It is possible to accurately determine whether or not the foreign object is likely to be damaged.

According to a third aspect of the present invention, there is provided a backside foreign object detection method in which a substrate to be processed is passed through a floating area of a floating stage provided with a large number of jet outlets and a large number of suction ports at a predetermined flying height. In a coating apparatus that forms a coating film of the processing liquid by supplying a processing liquid onto the substrate that is transported and passes below a slit nozzle that is disposed above the floating region, and adheres to the back surface of the substrate. A foreign matter detection method for detecting a foreign matter that is harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, facing both sides of the levitation stage. Between the light projecting unit and the light receiving unit arranged in a horizontal direction, the light beam horizontally passing across the upper surface of the substrate passing through the floating region is transmitted and received, and the amount of light beam received from the light receiving unit is Receiving A first step of acquiring a quantity signal, and a profile of the light receiving quantity of the light beam, which is an inverted mountain shape on the time axis, based on the received light quantity signal, and monitoring the received light quantity waveform of the light beam A second step of generating an alarm signal indicating that the harmful backside foreign matter has been detected when an inverted chevron profile having a size exceeding a predetermined reference size is detected. Is a third step of obtaining a decrease in the received light amount of the light beam with respect to a predetermined received light amount reference value at a plurality of extraction points set at predetermined intervals on the time axis, and from the plurality of extracted points A fourth step of integrating the obtained received light amount decrease, and comparing the integrated value of the received light amount decrease with a predetermined threshold, and when the integrated value exceeds the threshold, The reference size in the waveform of the received light amount of the light beam Than including the size of the fifth step determines that contains inverted chevron profile.
The backside foreign object detection device according to the third aspect of the present invention is configured to pass the substrate to be processed so as to pass through a floating area of a floating stage provided with a large number of jet ports and a large number of suction ports in a mixed manner. In a coating apparatus for transporting and supplying a processing liquid toward the substrate passing under a slit nozzle disposed above the floating region, and forming a coating film of the processing liquid on the substrate, A backside foreign matter detection device for detecting a backside foreign matter adhering to the backside of a substrate and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, sandwiching the floating stage And having a light projecting portion and a light receiving portion arranged to face both sides of the light projecting portion and the light receiving portion. Sent and received between The light sensor outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit, and the received light amount waveform of the light beam is a time axis based on the received light amount signal output from the light sensor. The above-mentioned profile having an inverted chevron is monitored, and when the inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform of the received light amount of the light beam, the harmful backside foreign matter is detected. A signal processing unit that generates an alarm signal, and the signal processing unit receives the light beam with respect to a predetermined received light amount reference value at a plurality of extraction points set at predetermined intervals on a time axis. A first calculation unit for obtaining a decrease in the amount of light; a second calculation unit for integrating the decrease in the amount of received light obtained from each of the plurality of extraction points; and an integrated value for the decrease in the amount of received light. Compared to the value There when it exceeds the threshold value, and a said light beam 3 determines that the magnitude of inverted chevron profile of exceeding the reference size in a received light amount of the waveform is included in the calculation unit.
In the backside foreign object detection method or the backside foreign object detection device according to the third aspect, the light reception amount of the light beam is targeted for monitoring a profile in which the waveform of the light reception amount of the light beam obtained from the optical sensor is inverted on the time axis. When an inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform, an alarm signal indicating that a harmful backside foreign object has been detected is generated. Specifically, a decrease in the amount of received light beam with respect to a predetermined light reception amount reference value is obtained at a plurality of extraction points set at predetermined intervals on the time axis, and obtained from each of the plurality of extraction points. Accumulate the decrease in received light amount. Then, the integrated value for the decrease in received light amount is compared with a predetermined threshold value, and when the integrated value exceeds the threshold value, the inverse of the size exceeding the reference size in the received light amount waveform of the light beam. It is determined that the Yamagata profile is included. As a result, the backside foreign material that is the basis of the inverted chevron profile is harmful to the slit nozzle without being affected by the noise component included in the received light amount signal (that is, the upper surface of the substrate is rubbed against the slit nozzle). It is possible to accurately determine whether or not the foreign object is likely to be damaged.
According to a fourth aspect of the present invention, there is provided a backside foreign object detection method in which a substrate to be processed is passed through a floating area of a floating stage provided with a large number of jet outlets and a large number of suction ports in a mixed manner. In a coating apparatus that forms a coating film of the processing liquid by supplying a processing liquid onto the substrate that is transported and passes below a slit nozzle that is disposed above the floating region, and adheres to the back surface of the substrate. A foreign matter detection method for detecting a foreign matter that is harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, facing both sides of the levitation stage. Between the light projecting unit and the light receiving unit arranged in a horizontal direction, the light beam horizontally passing across the upper surface of the substrate passing through the floating region is transmitted and received, and the amount of light beam received from the light receiving unit is Receiving A first step of acquiring a quantity signal, and a profile of the light receiving quantity of the light beam, which is an inverted mountain shape on the time axis, based on the received light quantity signal, and monitoring the received light quantity waveform of the light beam A second step of generating an alarm signal indicating that the harmful backside foreign matter has been detected when an inverted chevron profile having a size exceeding a predetermined reference size is detected. The model pattern of the inverted chevron profile having the reference size or a size slightly smaller than the reference size is applied as a ruler to the received light amount waveform of the light beam on the time axis, and a predetermined pattern on the time axis within the model pattern. If an inverted chevron profile with a size exceeding the model pattern is found at a plurality of comparative points set at intervals, it is an inverse of the size exceeding the reference size. Determined to be in the form profile.
According to a fourth aspect of the present invention, there is provided a backside foreign object detection device that allows a substrate to be processed to pass through a floating region of a floating stage provided with a mixture of a large number of ejection ports and a large number of suction ports at a predetermined flying height. In a coating apparatus for transporting and supplying a processing liquid toward the substrate passing under a slit nozzle disposed above the floating region, and forming a coating film of the processing liquid on the substrate, A backside foreign matter detection device for detecting a backside foreign matter adhering to the backside of a substrate and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction, sandwiching the floating stage And having a light projecting portion and a light receiving portion arranged to face both sides of the light projecting portion and the light receiving portion. Sent and received between The light sensor outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit, and the received light amount waveform of the light beam is a time axis based on the received light amount signal output from the light sensor. The above-mentioned profile having an inverted chevron is monitored, and when the inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform of the received light amount of the light beam, the harmful backside foreign matter is detected. A signal processing unit that generates an alarm signal of the above-mentioned, and the signal processing unit has a model of an inverted chevron profile having a size of the reference size or one size smaller than the reference size in the waveform of the amount of received light beam on the time axis By applying a pattern as a ruler, upside-down mountains with a size larger than the model pattern at a plurality of comparison points set at predetermined intervals on the time axis in the model pattern If you find the profile, which has a determining operation unit to be inverted chevron profile of magnitude greater than the reference size.
In the backside foreign matter detection method or the backside foreign matter detection device according to the fourth aspect, a profile in which the waveform of the light reception amount of the light beam obtained from the optical sensor is inverted upside down on the time axis is monitored, and the light reception amount of the light beam When an inverted chevron profile with a size exceeding a predetermined reference size is detected in the waveform, an alarm signal indicating that a harmful backside foreign object has been detected is generated. Specifically, a model pattern of an inverted chevron profile having a reference size or a size slightly smaller than the reference size is applied as a ruler to the received light amount waveform on the time axis, and a predetermined pattern on the time axis within the model pattern. If an inverted chevron profile having a size exceeding the model pattern is found at a plurality of comparison points set at intervals, it is determined that the inverted chevron profile has a size exceeding the reference size. As a result, the backside foreign material that is the basis of the inverted chevron profile is harmful to the slit nozzle without being affected by the noise component included in the received light amount signal (that is, the upper surface of the substrate is rubbed against the slit nozzle). It is possible to accurately determine whether or not the foreign object is likely to be damaged.

  The coating apparatus according to the present invention includes a levitation stage having a first levitation region provided with a mixture of a large number of ejection openings and a large number of suction ports, and the substrate floating in the air on the levitation stage. The slit nozzle is provided on the substrate passing through the first floating region, and having a transport mechanism for transporting the first floating region and a slit nozzle disposed above the first floating region. A treatment liquid supply unit for supplying a treatment liquid, and a substrate upstream of the slit nozzle in the substrate transport direction, attached to the back surface of the substrate passing through the first floating region, and It has the backside foreign matter detection device of the present invention for detecting harmful backside foreign matter.

  According to the backside foreign matter detection method or the backside foreign matter detection device of the present invention, the above-described configuration and operation are harmful because there is a risk of scratching the slit nozzle by rubbing the top surface of the substrate in the spin-less spin coating method. It is possible to accurately detect the backside foreign matter with high accuracy.

  In addition, according to the coating apparatus of the present invention, by providing the back surface detection apparatus of the present invention, it is possible not only to reliably prevent the slit nozzle from being damaged, but also unnecessary interruption of the coating processing operation caused by the back surface foreign matter. Therefore, the maintenance cost can be reduced and the coating processing efficiency can be improved.

It is a schematic plan view showing a main configuration of a resist coating apparatus to which the backside foreign matter detection method or backside foreign matter detection device of the present invention can be applied. It is a front view which shows typically the coating treatment operation | movement in the said resist coating device. It is a figure for demonstrating the leaf surface when a back surface foreign material becomes a problem in the said resist coating device. It is a figure for demonstrating the leaf surface when a back surface foreign material becomes a problem in the said resist coating device. It is a figure for demonstrating the effect | action of the back surface foreign material detection apparatus in the said resist coating apparatus. It is a block diagram which shows the structure of the back surface foreign material detection apparatus in embodiment. It is a side view which shows the arrangement configuration of the optical sensor in the back surface foreign material detection apparatus of embodiment. It is a partial enlarged front view which shows the rise of the board | substrate by a back surface foreign material, and the effect | action of the said optical sensor. It is a figure which shows the waveform of the light beam received light quantity obtained in the said optical sensor. It is a figure which shows the effect | action of the A / D converter in the said back surface foreign material detection apparatus. It is a block diagram which shows the structure of the calculating part in the signal processing part of the said back surface foreign material detection apparatus. It is a figure for demonstrating the effect | action of the sample value extraction part contained in the calculating part of the said signal processing part. It is a figure for demonstrating the effect | action of the reduction | decrease calculating part contained in the calculating part of the said signal processing part, and an integrating | accumulating part. It is a figure which shows the effect | action (application example) of the said signal processing part. It is a block diagram which shows the structure of the signal processing part in one modification. It is a figure which shows the effect | action (application example) of the signal processing part by the said modification.

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

  FIG. 1 shows the main configuration of a resist coating apparatus to which the backside foreign matter detection method or backside foreign matter detection apparatus of the present invention can be applied.

  This resist coating apparatus employs a levitation spinless coating method, and as shown in FIG. 1, a levitation stage 10 that floats a substrate to be processed, such as a glass substrate G for FPD, in the air by gas pressure, and the levitation A transport mechanism 12 for transporting the substrate G floating in the air on the stage 10 in the longitudinal direction (X direction) of the floating stage; a slit nozzle 14 for supplying a resist solution to the upper surface of the substrate G transported on the floating stage 10; It has.

The upper surface of the levitation stage 10 is divided into three regions, that is, a carry-in region M _IN , a coating region M _COT, and a carry-out region M _OUT along the substrate transfer direction (X direction). Among these, only a large number of jet nozzles 16 are provided in the carry-in area M _IN and the carry-out area M _OUT with a predetermined density, and many jet _nozzles 16 and suction ports 18 are provided with a predetermined density in the coating area M _COT. It is provided in a mixed manner.

Into the carry-in area _MIN , a substrate G for carrying the substrate G before the coating treatment from the external device in the previous stage by a flat flow by a sorter mechanism (not shown) or by delivery from a transfer robot (not shown) A portion (not shown) is provided. In the carry-out area M _OUT , the substrate G that has been subjected to the coating process is carried out to a subsequent external device by a flat flow by a sorter mechanism (not shown) or by delivery to a transfer robot (not shown). A substrate carry-out unit (not shown) is provided.

In the coating region M _COT , the slit nozzle 14 is provided above the stage so as to be movable up and down, and a nozzle refresh unit 24 that refreshes the slit nozzle 14 between coating processes is parallel to the substrate transport direction (X direction). It is provided to be movable.

As shown in FIG. 1, the transport mechanism 12 includes a pair of guide rails 26 </ b> A and 26 </ b> B that extend in the X direction with the levitation stage 10 interposed therebetween, and a pair of sliders 28 that can reciprocate along the guide rails 26 </ b> A and 26 </ b> B. And a substrate holding member (not shown) such as a suction pad provided on the slider 28 so as to detachably hold both side ends of the substrate G on the floating stage 10, and a linear movement mechanism (not shown). The slider G is moved in the substrate transport direction (X direction) to float and transport the substrate G from the loading area M _IN through the coating area M _COT to the unloading area M _OUT on the floating stage 10. It is configured.

  The slit nozzle 14 traverses the top of the levitation stage 10 in the horizontal direction (Y direction) orthogonal to the substrate transport direction, and passes from directly below the upper surface (processing surface) of the substrate G from a slit-like discharge port. The resist solution R is discharged in a strip shape. Further, the slit nozzle 14 is provided by a nozzle elevating mechanism 36 including, for example, a ball screw mechanism or a guide member, which is attached to a portal frame 30 installed across the floating stage 10 in parallel (in the Y direction) with the slit nozzle 14. The nozzle support member 38 that supports the nozzle 14 is configured to be movable (lifted / lowered) in the vertical direction (Z direction) integrally. The slit nozzle 14 is connected via a resist supply pipe 42 to a resist supply mechanism 40 (FIGS. 2 and 5) including a resist solution container and a liquid feed pump.

Here, the resist coating operation in this resist coating apparatus will be described. First, the substrate G from the front of the substrate processing apparatus (not shown) is loaded into loading area M _IN of floating stage 10 through the sorter mechanism or transport robot, where a slider 28 which has been waiting while holding the substrate G receive. On the levitation stage 10, the substrate G floats in the air by the pressure (lift) of air ejected from the ejection holes 16.

In this way, the substrate G is transported in the substrate transport direction (X direction) by the transport mechanism 12 while horizontally floating on the floating stage 10, and the slit nozzle 14 is applied to the substrate G when passing through the coating region _MCOT at the center of the stage. By discharging the resist solution R in a strip shape at a predetermined flow rate, a resist film coating RM having a uniform film thickness is formed from the front end side to the rear end side of the substrate G as shown in FIG. Go.

When the rear end of the substrate G passes under the slit nozzle 14, a resist coating film RM is formed on the entire surface of the substrate. Subsequently, the substrate G is then levitated and conveyed on the levitating stage 10 by the slider 28, and a rear stage unit (not shown) from the unloading area M _OUT set at the rear end of the levitating stage 10 via a sorter mechanism or a conveying robot. ).

As shown in FIG. 2, the flying heights H _IN and H _OUT for loading and unloading in the carry-in area M _IN and the carry-out area M _OUT of the levitation stage 10 do not require particularly high accuracy, for example, in the range of 250 to 350 μm. It only has to be kept inside.

On the other hand, the coating area M _COT of the levitation stage 10 is a place where the resist solution R is supplied from the upper slit nozzle 14 when the substrate G passes therethrough. Flying height H _COT in the coating region M _COT defines a coating gap K between the lower end of the slit nozzle 14 (discharge port) and the substrate upper surface (surface to be processed) (e.g. 100 [mu] m).

The coating gap K is an important parameter that affects the film thickness of the resist coating film RM and the resist consumption, and needs to be kept constant with high accuracy. Therefore, on the upper surface of the stage in the coating region M _COT , there are a jet port 16 for jetting high-pressure or positive-pressure compressed air and a suction port 18 for sucking air with negative pressure in order to float the substrate G at a desired flying height H _COT. Are mixed (FIG. 1). Then, a vertical upward force due to high-pressure air is applied from the jet port 16 to the portion passing through the coating region _MCOT of the substrate G, and simultaneously a vertical downward force due to a negative pressure suction force is applied from the suction port 18. Thus, by controlling the balance of the opposing forces, the flying height H _COT in the coating region M _COT is maintained near the set value (for example, 40 μm) with high accuracy.

Note that the size of the coating region M _COT in the substrate transport direction (X direction) is sufficient if it has a margin enough to stably form the narrow coating gap K as described above immediately below the slit nozzle 14. The size may be smaller than the size, for example, about 1/3 to 1/4.

  Here, with reference to FIGS. 2 to 4, a description will be given of a scene in which foreign matter adhering to the back surface of the substrate G becomes a problem in this resist coating apparatus.

As an example, though the foreign matter Q is attached to the rear surface of the loaded wafer G in floating stage 10, from the flying height H _IN size H _Q in the height direction of the foreign matter Q is carried region M _IN (250~350μm) _Is smaller than the flying height H _COT (40 μm) of the coating area M _COT .

As shown in FIG. 2, while the rear surface foreign matter Q is in carrying region M _IN, the substrate G is directly levitation transportation without receiving any influence from the foreign matter Q. However, as shown in FIG. 3, when this back surface foreign substance Q enters the coating region M _COT , it is sandwiched between the back surface of the substrate G and the top surface of the levitation stage 10, whereby the top surface of the substrate G adheres to the back surface foreign material Q. It rises in and are point G _Q. The size of the rise G _Q (the amount of increase) corresponds to the difference (H _Q −H _COT ) between the height direction size H _Q of the backside foreign material _Q and the flying height H _COT (40 μm). Accordingly, when the difference (H _Q −H _COT ) is greater than or equal to the coating gap K (100 μm), that is, when the size H _Q in the height direction of the back surface foreign material _Q is 140 μm or more, the back surface foreign material Q Swells immediately above the slit nozzle 14, the raised portion G _Q of the substrate G rubs the discharge port of the slit nozzle 14 above it. As a result, the discharge port of the slit nozzle 14 is damaged, and the slit nozzle 14 becomes unusable with a considerable probability.

In this embodiment, as shown in FIG. 5, by providing the back surface foreign object detection device 50 of the present invention, as described later, the above harmful (that is, the slit nozzle 14 rubs the upper surface of the substrate G). It is possible to reliably detect the backside foreign material Q (which may cause scratches) upstream of the slit nozzle 14 in the substrate transport direction (X direction). Then, in response to an alarm signal WS generated when the backside foreign object detection device 50 detects such a harmful backside foreign substance Q, the main control unit 52 immediately moves the slit nozzle 14 up and down through the nozzle lifting mechanism 36. Accordingly, the slit nozzle 14 dodge raised portion G _Q of the substrate G (avoid sliding or collision) that can damage the slit nozzle 14 is prevented.

  In response to the alarm signal WS, the main controller 52 preferably controls the resist supply mechanism 40 to stop the resist discharge operation of the slit nozzle 14, and further controls the transport mechanism 12 to control the substrate G. You may stop conveyance of once.

  Further, in this embodiment, as will be described later, the backside foreign material q having a smaller size in the height direction than the harmful backside foreign material Q (that is, no risk of rubbing the upper surface of the substrate G against the slit nozzle 14). In contrast, the backside foreign object detection device 50 does not generate the alarm signal WS. As a result, a situation in which the coating treatment operation being performed is interrupted unnecessarily is avoided, and a reduction in the apparatus operating rate due to the foreign matter on the back surface is avoided as much as possible.

  Hereinafter, the configuration and operation of the backside foreign object detection device 50 according to an embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIGS. 5 and 6, the back surface foreign object detection device 50 in this embodiment includes an optical sensor 54 disposed on the upstream side of the slit nozzle 14 in the substrate transport direction (X direction), and an output from the optical sensor 54. And a signal processing unit 56 for detecting harmful backside foreign matter Q adhering to the substrate G by predetermined signal processing based on the received light amount signal AS.

The optical sensor 54 includes a light projecting unit 58 and a light receiving unit 60. As shown in FIGS. 5 and 7, the light projecting unit 58 and the light receiving unit 60 are separated from the slit nozzle 14 by an appropriate distance (for example, 60 to 80 mm) upstream in the substrate transport direction (X direction). They are arranged opposite to both sides of (application region M _COT ).

  The light projecting unit 58 may be a single LD (semiconductor laser), but is preferably a two-dimensional LD array in which a large number of LDs are arranged in a vertical and horizontal matrix, and a drive current from a light emission drive circuit (not shown). For example, and emits a light beam LB having a beam cross-sectional size of 1 mm in length and 5 mm in width. At this time, the lower end portion of the light beam LB emitted from the light projecting unit 58 is cut off on one side surface of the substrate G, and only the beam portion that propagates horizontally in a space higher than the upper surface of the substrate G is the light receiving unit 60. The height position of the beam optical path may be set or adjusted so as to reach the light receiving surface.

  The light receiving unit 60 is composed of a two-dimensional CCD (Charge-Coupled Device) in which a large number of light receiving cells are arranged in a vertical and horizontal matrix within a total light receiving area of a certain size (for example, 1 mm in length and 5 mm in width). In a cycle, the light received in each light receiving cell is photoelectrically converted to generate a signal charge or analog light reception signal AS representing the light reception amount AE, and the light reception signal AS is serialized in time series by a predetermined transfer method. To output.

As shown in FIG. 8, when the harmful backside foreign matter Q (or harmless backside foreign matter q) passes through the optical sensor 54, the light shielding portion of the light beam LB is increased by the raised portion _GQ ( _Gq ) of the substrate G, That is, the light receiving amount of the light beam LB in the light receiving unit 60 decreases, and an inverted mountain-shaped (mortar-shaped) profile AE _Q (AE _q ) appears in the waveform of the light receiving amount AE as shown in FIG.

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

  As shown in FIG. 10, the A / D converter 62 converts the received light amount signal AS from the optical sensor 54 (light receiving unit 60) into a digital signal, that is, received light amount data... A0 with a predetermined period Δt (for example, 1.5 msec). , A1, A2,. The received light amount data memory 64 temporarily overwrites the received light amount data output from the A / D converter 62 by a part (a constant data amount) from the present time to a predetermined time before (A0, A1, A2,...). To store.

  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.

  The operation of the sample value extraction unit 72 will be described with reference to FIG. In the figure, [1], [2], [3], and [4] represent extraction points. The sample value extraction unit 72 selects a plurality of (n), for example, four received light amount data (Ai-3p, A) at a predetermined time (p * Δt) from the received light amount data stored in the received light amount data memory 64. Ai-2p, Ai-p, Ai) are 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 10 (10Δt minutes) before that. The received light amount data A20, the received light amount data A10 for 10 (10Δt) before and the received light amount data A0 for 10 (10 Δt) before that are extracted simultaneously.

  When the received light amount data A31 next to 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 is set to four pieces every predetermined time (10 Δt minutes) in the same manner as described above. The received light amount data (A1, A11, A21, A31) is extracted. When the received light amount data A32 next to the received light amount data A31 is stored in the received light amount data memory 64, the sample value extraction unit 72 immediately after that, in the same manner as described above, every 4 time intervals (10 Δt minutes). The received light amount data (A2, A12, A22, A32) are extracted.

Note that the number n (preferably 3 or more) of extraction points and the interval p used in the sample value extraction unit 72 are given from the setting unit 68 (FIG. 6).

The operation of the decrease calculation unit 74 will be described with reference to FIG. The decrease calculation unit 74 performs the received light amount decrease (δi-3p, δi−) for the four received light amount data (Ai-3p, Ai-2p, Ai-p, Ai) extracted by the sample value extraction unit 72, respectively. 2p, δi-p, δi). Here, a _{δi-3p = N AE -Ai-} 3p, δi-2p = N AE -Ai-2p, δi-p = N AE -Ai-p, δi = N AE -Ai, N AE light receiving amount This is the reference value. Thus, for example, time received light amount decrease obtained by t30 (δ0, δ10, δ20, δ30) _{is, δ0 = N AE -A0, δ10} = N AE -A10, δ20 = N AE -A20, δ30 = N AE -A30 It is.

The received light amount reference value N _AE is preferably a value of the received light beam amount obtained by the light receiving unit 60 when the leading portion of the substrate G passes through the optical sensor 54 in the substrate transport direction (X direction). Light obtained by the light receiving unit 60 at a fixed time (for example, 10 msec) before [4], which is the oldest among the four extraction points [1], [2], [3], and [4]. It corresponds to the value of the amount of received light and is set to 100%.

The decrease calculation unit 74 normalizes the received light amount data (A 0 , A 10 , A 20 , A 30 ) in% display and obtains the received light amount decrease (δ 0, δ 10, δ 20, δ 30) in% display. Therefore, for example, when (A 0 , A 10 , A 20 , A 30 ) = (100, 98, 95, 97), (δ 0, δ 10, δ 20 , δ 30 ) = (0, 2, 5, 3) Become.

  The accumulating unit 76 multiplies four received light amount reductions (δi−3p, δi−2p, δi−p, δi) output from the decrease calculation unit 74 collectively or in one frame (frame) FL. The operation result Ii is output. For example, when (δ0, δ10, δ20, δ30) output from the decrease calculation unit 74 is (0, 2, 5, 3), multiplication of 0 * 2 * 5 * 3 is performed, and the calculation result is Ii = 0 is output.

The determination unit 78 compares the calculation result I _i output from the integration unit 76 with the determination threshold value I _S from the setting unit 68 (FIG. 6), determines the magnitude relationship between them, and I _i ≦ I _S For example, the determination output signal W is set to the logical value L, and when I _i > I _S , the determination output signal W is set to the logical value H, for example. When a determination output signal W having a logical value H is output from the determination unit 78, an alarm signal WS is output from the output unit 70 (FIG. 6).

As described above, in the signal processing unit 56, a plurality (n) of, for example, four (4), for example, set by the sample value extraction unit 72 and the decrease calculation unit 74 with a predetermined interval (p * Δt) on the time axis. number of extraction points [1], [2], [3], [4] the decrease in the light beam received light amount AE for a given amount of received light reference value N _AE in (δi-3p, δi-2p , δi-p, A first calculation for obtaining δi) is performed. Then, the integration unit 76 reduces the received light amount (δi-3p, δi-2p, δi-p, δi) respectively obtained from the plurality of extraction points [1], [2], [3], [4]. ) Is performed. Finally, the determination unit 78 compares the integrated value I _i corresponding to the decrease in the amount of received light with a predetermined threshold value I _S, and when the integrated value I _i exceeds the threshold value I _S , the logical value H A third calculation for obtaining the determination result W is performed.

  Here, the fact that the determination unit 78 outputs the determination result W of the logical value H means that the reverse foreign object detection device 50 includes an inverted chevron profile whose size exceeds the reference size in the waveform of the light beam received light amount AE. Means that it is determined that

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 The reference size (diameter size D _Q , received light size) of the inverted chevron profile that appears in the waveform of the received light amount AE when the size H _{Q in the} height direction is the lower limit value (that is, the value obtained by adding the flying height H _COT and the coating gap K) The optimum or moderate value is set according to the amount decrease peak value δ _Q ).

For example, the thickness T _G of the substrate G is 700 .mu.m, the flying height H _COT is 40 [mu] m, if the coating gap K is 100 [mu] m, the size H _Q in height direction adverse backside foreign matter Q of 140μm adhered to the back surface of the substrate G If so, the raised 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 chevron profile appearing in the waveform of the received light amount AE is 70 μm, and the received light amount decrease peak value δ _Q is 7%. These values (70 μm, 7%) are obtained from experiments.

  Since the substrate transport 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 with the X axis in the substrate transport direction with a constant proportional relationship (X = vt).

  Therefore, theoretically, if a threshold value of, for example, 5% to 7% is applied, most harmful backside foreign matter Q should be detectable. However, in actuality, the received light amount signal AS output from the optical sensor 54 is mixed with a noise component with a signal-to-noise ratio close to 1 due to the fluctuation of the substrate G being floated and the vibration of the optical sensor 54 itself. Such a determination method is not effective.

Therefore, in this embodiment, the received light amount decrease amount (δi−3p) of one frame FL obtained from the plurality (n) of extraction points [1], [2], [3], [4] as described above. , Δi-2p, δi-p, δi) are multiplied (or added), and the magnitude of the inverted chevron profile is measured by the calculation result (integrated value) I _i .

In this method, the total time width T _S of the extraction points is moderately smaller (preferably 1 / 2D _Q <DT _S <D _Q ) than the reference (lower limit) diameter size D _Q (70 μm) in the distance conversion DT _S. Is important, for example, DT _S = 60 μm. As a result, among the inverted chevron profiles, those whose diameter size is smaller than DT _S always have the integrated value I _{i at} or near zero, so that it can be determined that it is not the harmful backside foreign material Q. . Also, of the inverted chevron profile, what is greater than D T _S diameter size, the magnitude of the inverted chevron profile is reflected in the integrated value I _i, harmful by the threshold value I _S moderate values It can be reliably determined that the foreign object Q is the back surface.

For example, when the minimum toxic backside foreign matter Q in the height direction size H _Q as described above 140μm is attached to the rear surface of the substrate G, the waveform of the received light amount AE as shown in FIG. 14 (a) When the inverted chevron profile appears, the integrated value I _i is 1 * 4.5 * 6 * 2.5 = 67.5. The integrated value I _i is an attribute value unique to the inverted chevron profile that is hardly affected by the noise component. Therefore, by setting the threshold value _IS to 60, for example, it is possible to accurately and surely determine that the backside foreign matter is the harmful backside foreign matter Q.

Incidentally, if the size H _Q in the height direction harmful backside foreign matter Q of 190μm is attached to the rear surface of the substrate G, appears inverted chevron profile as shown in FIG. 14 (b) the waveform of the received light amount AE . In this case, the integrated value I _i is 8.5 * 9 * 5 * 2 = 675, which is well above the threshold value I _S (60). Can do.

Further, when a substantially harmless back surface foreign substance q having a height size H _Q of 100 μm is attached to the back surface of the substrate G, the waveform of the received light amount AE has an inverted chevron profile as shown in FIG. Appears. In this case, the integrated value I _i is 0 * 1 * 3 * 0.2 = 0, and it can be clearly determined that the backside foreign matter is not the harmful backside foreign matter Q.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the technical idea.

For example, as shown in FIG. 15, the calculation unit 66 of the signal processing unit 56 can be configured by a sample value extraction unit 72, a pattern comparison unit 80, and a determination unit 82. Here, as shown in FIG. 16, the pattern comparison unit 80 has a reference size (reference diameter size DQ, reference received light amount decrease peak value δ _Q ) or slightly smaller than the waveform of the received light beam amount on the time axis. The model pattern MP of the inverted chevron profile having the size is applied as a ruler, and the received light amount decrease amount (δi-4p, δi-3p, δi-) at the plural chevron profiles (for example, five locations) [1] to [5] 2p, δi-p, δi) and the model pattern MP are compared, and the magnitude relationship is output as a binary value of +/−. The data of the model pattern MP is given from the setting unit 68 (FIG. 6).

For example, when the minimum harmful back foreign material Q having a height size H _Q of 140 μm is attached to the back surface of the substrate G, it becomes as shown in FIG. 16 (a), and the comparison points [1] to [5] , The amount of decrease in received light amount (δi-4p, δi-3p, δi-2p, δi-p, δi) of the inverted chevron profile exceeds the model pattern MP, so that the pattern comparison unit 80 (+, +, +, +, +) Comparison result output is obtained. In this case, since all the comparison result outputs are +, the determination unit 82 outputs a determination result W of a logical value H indicating that the harmful backside foreign matter Q has been detected.

Further, when a harmful back foreign material Q having a size H _Q of 190 μm in the height direction adheres to the back surface of the substrate G, it becomes as shown in FIG. 16 (b), and again comparison points [1] to [5] , The amount of decrease in received light amount (δi-4p, δi-3p, δi-2p, δi-p, δi) of the inverted chevron profile exceeds the model pattern MP, so that the pattern comparison unit 80 (+, +, +, +, +) Comparison result output is obtained, and the determination unit 82 outputs a determination result W of a logical value H indicating that the harmful backside foreign matter Q is detected.

However, when a substantially harmless back surface foreign material q having a size H _Q of 100 μm in the height direction adheres to the back surface of the substrate G, it becomes as shown in FIG. ], The amount of light received by the inverted chevron profile (δi-4p, δi-3p) exceeds the model pattern MP, but at the comparison points [1], [2], and [3], the amount of light received by the inverted chevron profile is reduced. Minutes (δi−2p, δi-p, δi) are below the model pattern MP. In this case, the comparison result output of (+, +, −, −, −) is obtained from the pattern comparison unit 80. Accordingly, the determination unit 82 outputs the determination result W of the logical value L indicating that it is not the harmful backside foreign material Q because a part of the comparison result output is “−”.

  As the treatment 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, and a wiring material can be used, and various chemical liquids, developer liquids, rinse liquids, and the like are also possible. . The substrate to be processed 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 are also possible. The backside foreign matter detection method and backside foreign matter detection apparatus of the present invention can be suitably applied to a flat-flow type coating apparatus, but can also be applied to other types of substrate processing apparatuses that adopt a flat-flow type.

DESCRIPTION OF SYMBOLS 10 Floating stage 12 Conveyance mechanism 14 Slit nozzle 16 Jet outlet 18 Suction port 40 Resist supply mechanism 50 Back surface foreign material detection apparatus 5 4 Optical sensor 5 6 Signal processing part

Claims (30)

A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for forming a coating film of the processing liquid by supplying a processing liquid onto the substrate that passes further below, the backside foreign matter attached to the back surface of the substrate and harmful to the slit nozzle A backside foreign matter detection method for detecting at a position upstream of the slit nozzle in the substrate transport direction,
Between the light projecting unit and the light receiving unit arranged to face both sides of the levitation stage, a light beam horizontally passing across the upper surface of the substrate passing through the levitation region is transmitted and received, A first step of obtaining a received light amount signal representing a received light amount of the light beam from the light receiving unit;
On the basis of the received light amount signal, a profile waveform of the light receiving amount of the light beam is inverted chevron on the time axis to be monitored, the size exceeding a predetermined reference size in amount of light received waveform of the light beam of when detecting the inverted chevron profile, it has a second step of generating an alarm signal indicative of the detection of the harmful backside foreign matter,
The backside foreign matter detection method , wherein the reference size includes a reference received light amount decrease peak value in a height direction and a reference diameter size in a horizontal direction .   The reference light reception amount decrease peak value and the reference diameter size depend on the thickness of the substrate, the flying height, and the coating gap between the slit nozzle and the substrate, and are set based on experimental values. The backside foreign matter detection method according to claim 1. A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for forming a coating film of the processing liquid by supplying a processing liquid onto the substrate that passes further below, the backside foreign matter attached to the back surface of the substrate and harmful to the slit nozzle A backside foreign matter detection method for detecting at a position upstream of the slit nozzle in the substrate transport direction,
Between the light projecting unit and the light receiving unit arranged to face both sides of the levitation stage, a light beam horizontally passing across the upper surface of the substrate passing through the levitation region is transmitted and received, A first step of obtaining a received light amount signal representing a received light amount of the light beam from the light receiving unit;
On the basis of the received light amount signal, a profile waveform of the light receiving amount of the light beam is inverted chevron on the time axis to be monitored, the size exceeding a predetermined reference size in amount of light received waveform of the light beam of when detecting the inverted chevron profile, it has a second step of generating an alarm signal indicative of the detection of the harmful backside foreign matter,
A backside foreign matter detection method for setting a lower limit value of the size in the height direction as the harmful backside foreign matter based on a value obtained by adding the flying height and a coating gap between the slit nozzle and the substrate. . A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for forming a coating film of the processing liquid by supplying a processing liquid onto the substrate that passes further below, the backside foreign matter attached to the back surface of the substrate and harmful to the slit nozzle A backside foreign matter detection method for detecting at a position upstream of the slit nozzle in the substrate transport direction,
Between the light projecting unit and the light receiving unit arranged to face both sides of the levitation stage, a light beam horizontally passing across the upper surface of the substrate passing through the levitation region is transmitted and received, A first step of obtaining a received light amount signal representing a received light amount of the light beam from the light receiving unit;
On the basis of the received light amount signal, a profile waveform of the light receiving amount of the light beam is inverted chevron on the time axis to be monitored, the size exceeding a predetermined reference size in amount of light received waveform of the light beam of when detecting the inverted chevron profile, it has a second step of generating an alarm signal indicative of the detection of the harmful backside foreign matter,
The second step includes
A third step of obtaining a decrease in the received light amount of the light beam with respect to a predetermined received light amount reference value at a plurality of extraction points set at predetermined intervals on the time axis;
A fourth step of integrating the received light amount decrease obtained from each of the plurality of extraction points;
The integrated value of the decrease in the amount of received light is compared with a predetermined threshold value, and when the integrated value exceeds the threshold value, the received light amount waveform of the light beam is larger than the reference size. A fifth step of determining that the inverted chevron profile is included;
A method for detecting foreign matter on the back surface. 5. The backside foreign matter detection method according to claim 4 , wherein, in the third step, a decrease in the received light amount of the light beam is obtained by percentage display, and in the fourth step, the integration of the decrease in the received light amount is performed by multiplication. The received light quantity reference value is the value of the amount of light received obtained light beam by the light receiving portion when the head portion of the substrate in the substrate conveying direction has passed through the light projecting unit and the light receiving unit, according to claim 4 Or the back surface foreign material detection method of Claim 5 . The received light quantity reference value, which is a value of said received light amount of the most time-old light beam obtained by the light receiving portion before a predetermined time than among a plurality of sampled points, claim 4 or claim 5. The backside foreign matter detection method according to 5. The backside foreign matter detection method according to any one of claims 4 to 7, wherein the reference size includes a reference received light amount decrease peak value in a height direction and a reference diameter size in a horizontal direction. The backside foreign object detection method according to claim 8 , wherein a time width from the beginning to the end of the plurality of extraction points is smaller than the reference diameter size and larger than half of the reference diameter size. The backside foreign matter detection method according to any one of claims 4 to 9, wherein the plurality of extraction points are provided at three or more locations. A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for forming a coating film of the processing liquid by supplying a processing liquid onto the substrate that passes further below, the backside foreign matter attached to the back surface of the substrate and harmful to the slit nozzle A backside foreign matter detection method for detecting at a position upstream of the slit nozzle in the substrate transport direction,
Between the light projecting unit and the light receiving unit arranged to face both sides of the levitation stage, a light beam horizontally passing across the upper surface of the substrate passing through the levitation region is transmitted and received, A first step of obtaining a received light amount signal representing a received light amount of the light beam from the light receiving unit;
On the basis of the received light amount signal, a profile waveform of the light receiving amount of the light beam is inverted chevron on the time axis to be monitored, the size exceeding a predetermined reference size in amount of light received waveform of the light beam of when detecting the inverted chevron profile, it has a second step of generating an alarm signal indicative of the detection of the harmful backside foreign matter,
In the second step, a model pattern of an inverted chevron profile having the reference size or a size slightly smaller than the reference size is applied to the waveform of the received light amount of the light beam on the time axis as a ruler. If an inverted chevron profile having a size exceeding the model pattern is found at a plurality of comparison points set at predetermined intervals on the axis, it is determined that the inverted chevron profile has a size exceeding the reference size. Backside foreign object detection method. A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for supplying a treatment liquid toward the substrate passing further below and forming a coating film of the treatment liquid on the substrate, the adhesion to the back surface of the substrate and the slit nozzle A backside foreign matter detection device for detecting harmful backside foreign matter at a position upstream of the slit nozzle in the substrate transport direction,
A light projecting unit and a light receiving unit disposed opposite to each other on both sides of the levitation stage, and a light beam traversing horizontally across the upper surface of the substrate passing through the levitation region; An optical sensor that transmits and receives light to and from the light receiving unit, and outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit;
Based on the received light amount signal output from the optical sensor, a profile in which the waveform of the received light amount of the light beam has an inverted mountain shape on the time axis is monitored, and a predetermined amount of the received light amount waveform of the light beam is set as a monitoring target. of when detecting the magnitude inverted chevron profile of exceeding the reference size, it has a signal processing unit for generating an alarm signal indicative of the detection of the harmful backside foreign matter,
The backside foreign matter detection device, wherein the reference size includes a reference received light amount decrease peak value in a height direction and a reference diameter size in a horizontal direction. The signal processing unit is configured to set the reference received light amount decrease peak value and the reference that are set based on experimental values depending on the thickness of the substrate, the flying height, and a coating gap between the slit nozzle and the substrate. The backside foreign object detection device according to claim 12 , wherein a diameter size of 10 mm is used. A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for supplying a treatment liquid toward the substrate passing further below and forming a coating film of the treatment liquid on the substrate, the adhesion to the back surface of the substrate and the slit nozzle A backside foreign matter detection device for detecting harmful backside foreign matter at a position upstream of the slit nozzle in the substrate transport direction,
A light projecting unit and a light receiving unit disposed opposite to each other on both sides of the levitation stage, and a light beam traversing horizontally across the upper surface of the substrate passing through the levitation region; An optical sensor that transmits and receives light to and from the light receiving unit, and outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit;
Based on the received light amount signal output from the optical sensor, a profile in which the waveform of the received light amount of the light beam has an inverted mountain shape on the time axis is monitored, and a predetermined amount of the received light amount waveform of the light beam is set as a monitoring target. of when detecting the magnitude inverted chevron profile of exceeding the reference size, it has a signal processing unit for generating an alarm signal indicative of the detection of the harmful backside foreign matter,
A backside foreign matter detection device in which a lower limit value of the size in the height direction as the harmful backside foreign matter is set on the basis of a value obtained by adding the flying height and a coating gap between the slit nozzle and the substrate. . A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for supplying a treatment liquid toward the substrate passing further below and forming a coating film of the treatment liquid on the substrate, the adhesion to the back surface of the substrate and the slit nozzle A backside foreign matter detection device for detecting harmful backside foreign matter at a position upstream of the slit nozzle in the substrate transport direction,
A light projecting unit and a light receiving unit disposed opposite to each other on both sides of the levitation stage, and a light beam traversing horizontally across the upper surface of the substrate passing through the levitation region; An optical sensor that transmits and receives light to and from the light receiving unit, and outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit;
Based on the received light amount signal output from the optical sensor, a profile in which the waveform of the received light amount of the light beam has an inverted mountain shape on the time axis is monitored, and a predetermined amount of the received light amount waveform of the light beam is set as a monitoring target. of when detecting the magnitude inverted chevron profile of exceeding the reference size, it has a signal processing unit for generating an alarm signal indicative of the detection of the harmful backside foreign matter,
The signal processing unit
A first calculation unit for obtaining a decrease in the received light amount of the light beam with respect to a predetermined received light amount reference value at a plurality of extraction points set at predetermined intervals on the time axis;
A second calculation unit that integrates a decrease in received light amount respectively obtained from the plurality of extraction points;
The integrated value of the decrease in the amount of received light is compared with a predetermined threshold value, and when the integrated value exceeds the threshold value, the received light amount waveform of the light beam is larger than the reference size. A third calculation unit that determines that the inverted chevron profile is included;
A backside foreign object detection device including: The backside foreign object detection according to claim 15 , wherein the first calculation unit obtains a decrease in the received light amount of the light beam as a percentage display, and the second calculation unit performs multiplication by multiplying the decrease in the received light amount. apparatus. The received light quantity reference value is the value of the amount of light received obtained light beam by the light receiving portion when the head portion of the substrate in the substrate conveying direction has passed through the light projecting unit and the light receiving unit, according to claim 15 Or the back surface foreign material detection apparatus of Claim 16 . The received light quantity reference value, which is a value of said received light amount of the most time-old light beam obtained by the light receiving portion before a predetermined time than among a plurality of sampled points, claim 15 or claim 16. A backside foreign matter detection device according to 16 . The backside foreign object detection device according to any one of claims 15 to 18, wherein the reference size includes a reference light reception amount decrease peak value in a height direction and a reference diameter size in a horizontal direction. The backside foreign object detection device according to claim 19 , wherein a time width from the beginning to the end of the plurality of extraction points is smaller than the reference diameter size and larger than half of the reference diameter size. The back surface foreign matter detection device according to any one of claims 15 to 20, wherein the plurality of extraction points are provided at three or more locations. A slit nozzle that conveys a substrate to be processed so as to pass through a floating region of a floating stage provided with a mixture of a large number of jet nozzles and a large number of suction ports at a predetermined flying height, and is disposed above the floating region. In a coating apparatus for supplying a treatment liquid toward the substrate passing further below and forming a coating film of the treatment liquid on the substrate, the adhesion to the back surface of the substrate and the slit nozzle A backside foreign matter detection device for detecting harmful backside foreign matter at a position upstream of the slit nozzle in the substrate transport direction,
A light projecting unit and a light receiving unit disposed opposite to each other on both sides of the levitation stage, and a light beam traversing horizontally across the upper surface of the substrate passing through the levitation region; An optical sensor that transmits and receives light to and from the light receiving unit, and outputs a received light amount signal representing the received light amount of the light beam from the light receiving unit;
Based on the received light amount signal output from the optical sensor, a profile in which the waveform of the received light amount of the light beam has an inverted mountain shape on the time axis is monitored, and a predetermined amount of the received light amount waveform of the light beam is set as a monitoring target. of when detecting the magnitude inverted chevron profile of exceeding the reference size, it has a signal processing unit for generating an alarm signal indicative of the detection of the harmful backside foreign matter,
Wherein the signal processing unit, by applying a model pattern of inverted chevron profile with the reference size or smaller size slightly than the amount of light received waveform of the light beam as a ruler on the time axis, a time axis in said model pattern If an inverted chevron profile with a size larger than the model pattern is found at a plurality of comparison points set at predetermined intervals above, an arithmetic unit that determines that the inverted chevron profile has a size exceeding the reference size A backside foreign matter detection device having: A levitation stage having a first levitation region provided with a mixture of a large number of jet outlets and a large number of suction ports;
A transport mechanism that holds the substrate floating in the air on the levitation stage and transports the substrate so as to pass through the first levitation region;
A treatment liquid supply unit that has a slit nozzle disposed above the first floating region, and supplies a treatment liquid from the slit nozzle onto the substrate that passes through the first floating region;
Claims for detecting a foreign substance that is attached to the back surface of the substrate passing through the first floating region and harmful to the slit nozzle at a position upstream of the slit nozzle in the substrate transport direction. The coating apparatus which has a back surface foreign material detection apparatus as described in any one of 12-22.   24. The apparatus according to claim 23, further comprising an elevating mechanism for moving the slit nozzle up and down, wherein the slit nozzle is moved up and down through the elevating mechanism in response to the alarm signal generated from the backside foreign object detection device. Coating device.   The coating apparatus according to claim 23 or 24, wherein a processing liquid discharge operation in the processing liquid supply unit is stopped in response to the alarm signal generated from the backside foreign matter detection apparatus.   The coating apparatus according to any one of claims 23 to 25, wherein a substrate transport operation in the transport mechanism is stopped in response to the alarm signal generated by the back surface foreign matter detection device.   27. The levitation stage has a second levitation region provided with a plurality of jetting ports for suspending the substrate upstream of the first levitation region in the substrate transport direction. The coating apparatus as described in.   28. The coating apparatus according to claim 27, wherein a loading unit for loading the substrate is provided in the second floating region.   The said levitation | floating stage has a 3rd levitation | floating area | region which provided many jet nozzles for floating the said board | substrate in the downstream of the said 1st levitation | floating area in a board | substrate conveyance direction. The coating apparatus as described in.   30. The coating apparatus according to claim 29, wherein an unloading unit for unloading the substrate is provided in the third floating region.

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