JP2001170539A - Film-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise uniformity of a discharge amount of processing liquid supplied onto a surface of a substrate from a supply nozzle in a coating apparatus of, for example, resist liquid. SOLUTION: The resist liquid is sent to a supply nozzle 6 by a bellows pump 8, the resist liquid is discharged onto a surface of a wafer W held almost horizontally by a wafer holling part 2 thus from the supply nozzle 6, and a film of the resist liquid is formed on the surface of the wafer W. In a supply system of the resist liquid, a pressure inside a supply duct 76 of the resist liquid between the bellows pump 8 and the supply nozzle 6 is detected by a pressure- detection part 77, and a pushing amount of a rod 82a of an air cylinder 82 of the bellows pump 8 is controlled by a control part C so that a discharge pressure of the resist liquid from the supply nozzle 6 becomes an almost constant pressure based on the detected value. Since an amount of the resist liquid discharged to the wafer W becomes almost constant thereby, a liquid film of a stabilized film thickness can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying a liquid, especially a resist liquid, made of a resin or the like dissolved on a substrate to be processed, such as a semiconductor wafer, an LCD substrate or an exposure mask, and forming a film of the liquid. The present invention relates to a film forming apparatus for forming.

[0002]

2. Description of the Related Art A mask for forming a circuit pattern on the surface of a substrate to be processed such as a semiconductor wafer or an LCD substrate is formed by applying a resist solution onto a substrate surface and then resisting light, an electron beam or an ion beam. It is obtained by irradiating the surface and developing. Among them, a spin coating method is mainly used as a method of applying a resist liquid. In this method, for example, as shown in FIG. 12, a substrate, for example, a semiconductor wafer (hereinafter, referred to as “wafer”) W is suction-held on a spin chuck 11 having a vacuum suction function, and the wafer W
After the resist solution 13 is dropped from the nozzle 12 to the center of the wafer W, the resist solution 13 is diffused over the entire wafer W by rotating the wafer W by rotating the wafer W at a high speed,
This is to form a substantially uniform resist liquid film over the entire surface of the wafer W.

In recent years, the line width of circuit patterns has become increasingly finer, and the line width of circuits is proportional to the thickness of the resist film and the exposure wavelength. I have. In the spin coating method, the resist film thickness can be reduced by increasing the rotation speed of the wafer W. For example, in the case of an 8-inch wafer W, the wafer W is rotated at a high rotation speed of 200 to 4000 rpm. ing.

However, this spin coating method has the following problems to be solved. First, in this method, when the size of the wafer W is increased, the peripheral speed at the outer peripheral portion is increased, so that turbulence of air is caused, and the turbulence tends to change the film thickness of the resist film. The resolution will be reduced. For this reason, in this method, 0.
If the film thickness is less than 4 μm, it is difficult to obtain a uniform coating film, and there is naturally a limit in the production of semiconductors having a thickness of about several giga or more.

Next, according to this method, in the process of diffusing the resist solution from the center of the wafer W toward the peripheral portion, the solvent contained in the resist solution evaporates sequentially.
For this reason, the viscosity of the resist liquid varies along the diffusion direction, and the thickness of the resist film formed between the central portion and the peripheral portion may vary.

Further, in this method, since the wafer W is rotated at a high speed, a large amount of the resist solution is scattered from the peripheral portion of the wafer W and wasted. According to one example, it is known that only 10% or less of the resist liquid supplied onto the wafer W contributes to the formation of the resist liquid film.

Further, in this method, it is necessary to rotate the wafer W in the cup in order to receive the scattered resist solution. However, the resist solution adhered to the cup may become particles and contaminate the wafer W. This requires frequent cleaning of the cup.

Further, in this method, the resist solution is also applied to a region outside the circuit formation region of the wafer W. However, if the resist solution is left in this region, it may cause the generation of particles in a later process. Therefore, the resist liquid in this region must be removed by a dedicated device called an edge remover immediately after the resist liquid coating step.

For this reason, as an alternative to the spin coating method, for example, as shown by a solid line in FIG. 13, for example, a nozzle for discharging a resist solution 13 onto the surface of the wafer W and a wafer W are relatively moved. Next, a method of applying the resist liquid 13 to the wafer W in a so-called one-stroke manner by reciprocating in the X-direction while intermittently feeding at a predetermined pitch in the Y-direction (hereinafter referred to as a "single-stroke writing method") is studied. ing. At this time, a resist member is applied only to the circuit formation region 14 by covering the wafer W with a mask member covering an area outside the circuit formation region 14.

[0010]

By the way, in a conventional resist coating apparatus employing the spin coating method, as shown in FIG. 14, a resist pump 13 such as a bellows pump 16 or the like pumps a resist buffer 13 in a resist reservoir tank 15. And is supplied to the surface of the wafer W through the supply nozzle 11 via the filter 17 and the like.

At this time, for example, the resist solution 13 for five wafers W is stored in the bellows pump 16, and one resist solution 13 is pushed out from this and supplied to the surface of the wafer W via the nozzle 11. I was

However, when such a supply system of the resist solution 13 is employed as it is in the one-stroke writing coating method, the following problems may occur. That is, in the spin coating method, the time during which the resist liquid is discharged from the nozzle 11 to the wafer W is about 1 to 4 seconds, whereas in the one-stroke writing method, the nozzle is relatively moved in the XY directions over the entire wafer W. Since the liquid is moved and the resist liquid 13 is continuously discharged during this time, the discharge time becomes considerably long, for example, about 1 minute.

Here, the discharge pressure of the resist solution 13 from the nozzle 11 directly affects the amount of the resist solution supplied to the wafer W. Therefore, in order to make the film thickness uniform, the discharge pressure of the resist solution 13 must be reduced. It is required to keep it almost constant. However, in the one-stroke coating method, the discharge time is considerably long as described above, and it is difficult to maintain a constant discharge pressure while the resist solution is supplied to the wafer W. As a result, the amount of the resist solution 13 supplied to the wafer W varies, and as a result, the uniformity of the thickness of the resist film may be deteriorated.

The present invention has been made under such circumstances, and an object of the present invention is to obtain a stable film thickness by suppressing a variation in a discharge amount of a processing liquid discharged from a supply nozzle onto a substrate. It is an object of the present invention to provide a film forming apparatus capable of forming a film.

[0015]

Therefore, in the present invention,
In a film forming apparatus for discharging a processing liquid from a supply nozzle onto a surface of a substrate held substantially horizontally by a substrate holding unit and forming a liquid film of the processing liquid on the surface of the substrate, the processing liquid is sent to the supply nozzle. A pump body and a pressing member for liquid supply are provided, and the processing liquid is sent into the pump body from the upstream side by pulling the pressing member, and the processing liquid is sent out from the pump body to the downstream side by pressing the pressing member. A pressurized pump in which the amount of the processing liquid sent to the downstream side is adjusted by a pressing amount of the pressing member, and a pressure detection for detecting a pressure in a flow path of the processing liquid between the pressurized pump and the supply nozzle. And a control unit for controlling a pressing amount of a pressing member of the pressing pump based on a detection value from the pressure detecting unit, and a flow path of a processing liquid between the pressing pump and a supply nozzle. Based on the pressure within Controlling the pressing amount of the pressing member of the pressing pump, and controlling the discharge amount of the treatment liquid supplied from the supply nozzle to the substrate surface.

In such a configuration, the discharge pressure of the processing liquid supplied to the substrate surface from the supply nozzle based on the pressure in the flow path of the processing liquid between the pressing pump and the supply nozzle becomes substantially constant. Since the pressing amount of the pressing member of the pressing pump is controlled so that the discharge amount of the processing liquid is uniform during the processing, a liquid film having a stable film thickness can be formed.

Further, in the present invention, a displacement meter for detecting a pressing amount of a pressing member of the pressing pump, and a control unit for controlling an operation of an alarm generating unit based on a detection value from the displacement meter are provided. The film forming apparatus may be configured to operate the alarm generating unit when the pressing amount of the pressing member of the pressing pump deviates from a preset reference range. An abnormality such as nozzle clogging can be detected at an early stage, an appropriate countermeasure can be taken, and a recovery time until a stable liquid film is formed again can be shortened.

Further, according to the present invention, a displacement gauge for detecting a pressing amount of a pressing member of the pressing pump, a cleaning unit for cleaning the supply nozzle, and a drive for moving the supply nozzle to the cleaning unit. Mechanism, and a control unit that controls the operation of the drive mechanism based on the detection value from the displacement meter, when the pressing amount of the pressing member of the pressing pump deviates from a predetermined reference range. The supply nozzle may be moved to a cleaning unit by the drive mechanism, and the film forming apparatus may be configured to perform cleaning of the supply nozzle. In this case, an abnormality such as clogging of the supply nozzle has occurred. Sometimes, the supply nozzle can be quickly cleaned without bothering the operator.

Still further, in the present invention, the supply nozzle is connected to a flow path of the processing liquid, and a discharge hole for discharging the processing liquid in a linear shape having a small diameter, A filter for removing air bubbles and the like from the processing liquid, which may be provided so as to close the flow path of the processing liquid, and in this case, the processing liquid may be removed due to the presence of the air bubbles. Fluctuations in the discharge pressure and the like can be suppressed, the processing liquid can be supplied stably to the substrate, and the uniformity of the liquid film thickness can be improved. At this time, it is desirable that the filter is made of a porous resin.

In the present invention, the processing liquid is discharged from the supply nozzle while the substrate holding unit and the supply nozzle are relatively driven along the surface direction of the substrate, and the processing liquid is discharged onto the surface of the substrate. The present invention can be applied to a film forming apparatus of a type for forming a film.

Further, the present invention comprises a mixing tank for adjusting a low-viscosity processing liquid by mixing a high-viscosity processing liquid and a solvent for the processing liquid, and the processing liquid having an adjusted viscosity in the mixing tank. The liquid may be sent to the supply nozzle by the pressurized pump. In this case, a high-viscosity treatment liquid can be used without limiting the viscosity, so that the versatility is improved. Here, an example of the processing liquid includes a resist liquid.

[0022]

FIG. 1 shows a film forming apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view showing a configuration of an embodiment applied to a resist liquid applying apparatus for applying a resist liquid to a semiconductor wafer (hereinafter, referred to as “wafer”) as a substrate to be processed, and FIG. 2 is a plan view thereof. .

1 and 2, reference numeral 2 denotes a wafer holder which forms a substrate holder, and the wafer holder 2 comprises a frame 3
Is held movably in the Y direction. Frame 3
Is a member formed in a channel shape that is opened upward, for example, is formed to be long in the Y direction, and one end side in the Y direction is a resist liquid application section R on which a resist liquid is applied, and the other end side Is a wafer load
It is configured as an unload section L. Also frame 3
Is provided with a pair of Y rails 31 extending over the resist coating section R and the wafer loading / unloading section L. The wafer holder 2 is provided with a Y slider 32 on the Y rail 31. Is held movably in the Y direction via
When the ball screw 34 is rotated by the Y drive motor 33, the ball screw 34 is driven via the nut 35 so as to be freely positioned in the Y direction.

The wafer holder 2 has a main body 21 formed in a cup shape and a wafer suction table 22 for holding the wafer W. The main body 21 is located at a position facing the lower surface of the wafer W. A liquid reservoir channel 23 for storing a solvent (thinner solution) is provided. The liquid reservoir channel 23 is filled with a solvent whose liquid temperature and liquid level are controlled, and the solvent is evaporated to thereby form a wafer W. Is kept in a solvent atmosphere of a predetermined concentration.

The wafer suction table 22 has a holding portion 24 for holding the wafer W on its upper surface, and a vacuum device (not shown) is connected to the holding portion 24 so that the wafer W can be vacuum chucked. Has become. The holding unit 24 is connected to a Zθ driving mechanism 25. When the wafer W holder 2 moves to the wafer loading / unloading unit L, the Z positioning / notch aligning unit 26 activates the Zθ driving mechanism 25. Then, a Z-direction operation for transferring the wafer W and a θ operation for notch alignment are performed. Further, a wafer suction table 2
2 is connected to an agitation generator (not shown),
An ultrasonic vibrator 27 for vibrating the wafer W held by suction is fixed.

Further, at four corners of the bottom surface of the main body 21 surrounding the wafer suction table 22 (wafer W), four forced exhausts connected to an exhaust device (not shown) for controlling the air flow in the main body 21 are provided. Ports 28a to 28d are formed. The exhaust flow rates from the forced exhaust ports 28a to 28d are individually controlled. For example, by performing exhaust from only the two exhaust ports 28a and 28b, the exhaust flow is biased in one direction in the main body 21. Then, a weak air flow is generated, thereby controlling the flow of the solvent volatilized from the applied resist solution, thereby suppressing excessive volatilization of the solvent.

In the wafer holder 2, a mask member 4 is held just above the wafer W, and the mask member 4 is driven in a direction (X direction) indicated by an arrow A in FIG. A mask member driving mechanism 41 for inserting and removing from the body 2 is provided. As shown in FIG. 3, the mask member 4 covers an area other than the circuit formation area 40 of the wafer W to prevent the resist solution from being applied to the peripheral portion of the wafer W. The member driving mechanism 41 takes out the mask member 4 contaminated with the resist solution from the resist coating apparatus through the insertion / removal passages 20 and 30 provided in the wafer holder 2 and the frame 3 as shown by an arrow A in FIG. It is transported to a mask member cleaning device indicated by reference numeral 42 in FIG. In FIG. 3, reference numeral 43 denotes a notch formed on the wafer W.

In the drawing, reference numeral 5 denotes a top plate with a temperature control function provided on the frame 3 so as to cover the upper part of the wafer holder 2, for example, a linear heater 51 is buried therein and generates heat at a predetermined temperature. It is configured to be. Accordingly, the top plate 5 has a function of maintaining and controlling the solvent atmosphere filled around the wafer W, and heats a supply nozzle 6 to be described later. It has a function to prevent "cut".

The top plate 5 is positioned so that it can continue to cover the wafer holder 2 only in the resist liquid application section R even when the wafer holder 2 is moved to the maximum in the Y direction. The wafer holder 2 is covered. A slit 52 for allowing the supply nozzle 6 to move in the X direction is formed in the middle of the top plate 5 in the Y direction. The slit 52 has a length corresponding to the width of the wafer W and 6 are provided with a width that allows insertion.

The supply nozzle 6 is a linear slide mechanism 5 that is installed at the upper end of the frame 3 along the X direction.
3. This linear slide mechanism 5
3 is an X rail 54, a slider 55 slidably provided on the X rail 54, a ball screw 56 for driving the slider 55, and a ball screw 56
The supply nozzle 6 is held by the slider 55 at a position corresponding to the slit 52 of the top plate 5, and the lower end of the supply nozzle 6 is held through the slit 52. It extends into the body 2. The X drive motor 57 and the Y drive motor 33 are configured to be operated synchronously by the nozzle / wafer drive unit 36, and the supply nozzle 6
Is moved while facing a predetermined path of the wafer W.

Next, the supply system of the resist liquid in the supply nozzle 6 will be described with reference to FIG. In the figure, reference numeral 71 denotes a high-viscosity resist solution tank for storing, for example, a high-viscosity resist solution 70, and 72 denotes a solvent tank for storing a solvent for the resist solution, for example, a thinner solution. The high-viscosity resist solution in the tank 71 and the thinner solution in the solvent tank 72 are sent to the mixing tank 73 by pumps P1 and P2, respectively, and then sent to the buffer tank 74 downstream of the mixing tank 73 by the pump P3. It is configured to be.

The mixing tank 73 is a tank for mixing a predetermined amount of a high-viscosity resist solution and a predetermined amount of a thinner solution to adjust a predetermined-viscosity resist solution, and has a stirring mechanism. The resist solution in the buffer tank 74 is filtered by a pressurizing pump, for example, a bellows pump 8 to a filter device 75.
Is supplied to the supply nozzle 6 through the nozzle 6 and is discharged from a discharge hole 60 of the nozzle 6 to be described later. The buffer tank 74, the filter device 75, and the supply nozzle 6
Are connected by a supply channel 76.

The present invention is characterized in that the discharge pressure of the resist liquid discharged from the supply nozzle 6 is controlled by adjusting the pressing amount of the rod of the bellows pump 8 provided on the downstream side of the buffer tank 74. First, bellows pump 8
Will be described. As shown in FIG. 5, for example, the pump includes a flexible pipe 81, an air cylinder 82, and a liquid feeding section 83.
And The flexible tube 81 is an elastic bellows made of a soft resin, and one end of the flexible tube 81 is fastened to the flange 83 a of the liquid supply unit 83, and the other end is pressed via the flange 84 a of the blind plate 84. Air cylinder 8 as a member
2 of the air cylinder 82
Is connected to a compressed air supply source 80 controlled by the control unit C.

The liquid feeding section 83 includes a liquid reservoir 85 and a pair of ball valves 86a and 86b provided on the upstream and downstream sides of the liquid reservoir 85, respectively. The downstream ball valve 86b includes hard balls 87a and 87b made of ceramic or the like, and stoppers 88a and 88b, respectively.

As shown in FIG. 5 (a), when the flexible pipe 81 is extended by pulling the rod 82a, the ball valve 8 on the upstream side is bent.
6a is opened, the liquid is sucked into the liquid reservoir 85, and FIG.
As shown in (b), the flexible pipe 8 is pressed by pushing the rod 82a.
When 1 is contracted, the upstream ball valve 86a closes, the downstream ball valve 86b opens, and the liquid is pushed out from the liquid reservoir 85 to the downstream side. That is, in this example, when the flexible pipe 81 is extended, the resist liquid flows from the buffer tank 74, and when the flexible pipe 81 is contracted, the resist liquid is sent toward the supply nozzle 6.

In the bellows pump 8 of this embodiment, the flexible pipe 81 and the liquid reservoir 85 store a resist liquid in an amount equal to or larger than the amount of the resist liquid necessary for applying the resist liquid to the five wafers W. The amount of resist liquid pushed out from the liquid reservoir 85 to the downstream side is controlled by the stroke amount (pressing amount) L of the rod 82a of the air cylinder 82. In this example, the flexible pipe 81 and the liquid reservoir 85 correspond to a pump body.

Next, the supply nozzle 6 will be described with reference to FIG. This supply nozzle 6 is closed, for example, on the upper side,
An upper member 61 formed of, for example, polyethylene terephthalate (PTFE) having a lower opening and a cylindrical opening having an upper opening and a lower closing, for example.
The lower member 62 is formed by combining the lower member 62 with a threaded portion 63 formed at a predetermined position, and the lower member 62 is screwed from the outside of the upper member 61. It has become so.

The upper surface of the upper member 61 is connected to one end of a supply channel 76 for supplying the resist solution from the filter device 75 to the supply nozzle 6, and the lower end of the supply channel 76 is closed. Is provided with a filter 64 made of a resin such as a PTFE film having a thickness of about 0.5 mm, for example.

Since the PTFE film is a porous film having a large number of fine holes, it can be used as the filter 64. In this example, for example, 0.05 μm to 10 μm
It is preferable to use a PTFE membrane having a pore size of about 5 μm. As a result, as described later, it is possible to prevent the transmission of bubbles having a size of, for example, about 5 μm contained in the resist solution and to allow only the resist solution to pass.

A step 65 corresponding to the shape of the filter 64 is formed on the lower member 62 immediately below the position where the threaded portion 63 is formed. The filter 64 is connected to the lower end of the upper member 61. The lower member 62 is fixed while being sandwiched between the step 65 and the lower member 62. Further, on the lower surface of the lower member 62, an ejection hole 60 having a diameter of, for example, about 10 μm to 200 μm for supplying a resist solution onto the wafer W is formed.

As a result, the supply flow path 7 is connected to the supply nozzle 6.
The resist solution supplied through 6 passes through a filter 66 provided to close the flow path 66 in a flow path 66 formed inside the upper member 61 and the lower member 62, The liquid is discharged onto the wafer W through the discharge holes 60.

In this example, for example, the pressure in the supply channel 76 between the filter device 75 and the supply nozzle 6 is detected by, for example, a pressure detector 77 of a diaphragm type strain detection system, and the control unit is controlled based on the detected value. Compressed air source 8 by C
0, the pressing amount (stroke amount) L of the rod 82a of the air cylinder 82 of the bellows pump 8 is adjusted.

The rod 82a of the air cylinder 82
Is detected by, for example, a displacement meter 78 using light, and the operation of the alarm generating section 79 is controlled by the control section C based on the detected value.

Next, the operation of the above embodiment will be described. First, the wafer holding body 2 is positioned at the wafer loading / unloading section L, and the holding section 24 is moved up and down to transfer the wafer W from the wafer transfer main arm (not shown) to the wafer suction table 22 to hold the wafer W by suction. . Subsequently, after the notch alignment of the wafer W is performed by the notch alignment unit 26, the holding unit 24 is lowered to accommodate the wafer W in the wafer holder 2. Next, the wafer holder 2 is positioned at the resist liquid application section R, and the mask member driving mechanism 4
1 holds the mask member 4 on the wafer.

On the other hand, in the resist liquid supply system, the resist liquid (high-viscosity resist liquid) having a viscosity of, for example, about 0.05 Pa · S in the high-viscosity resist liquid tank 71 and the thinner solution in the solvent tank 72 are pumped, respectively. A predetermined amount of liquid is sent to the mixing tank 73 by P1 and P2, where both are mixed,
A resist solution (low-viscosity resist solution) 70 having a predetermined viscosity, for example, a viscosity of about 0.003 Pa · S is prepared. Then, the resist solution 70 in the mixing tank 73 is sent to the buffer tank 74 by the pump P3 and stored therein.

The resist solution 70 in the buffer tank 74 is used for coating, for example, five wafers by pulling a rod 82a of the air cylinder 82 of the bellows pump 8 by a predetermined amount and extending the flexible tube 81 to a predetermined length. The amount of the resist solution 70 is sent to the flexible tube 81 and the liquid reservoir 85 and stored therein. Next, the resist liquid 70 in the pump 8 is sent to the supply nozzle 6 through the filter device 75 by pressing the rod 82a of the air cylinder 82 by a predetermined pressing amount, and the wafer W is discharged from the discharge hole 60 of the supply nozzle 6. Discharge is performed at a predetermined discharge pressure on the surface.

At this time, the discharge pressure of the resist liquid 70 discharged from the discharge holes 60 of the supply nozzle 6 is reduced.
Filter device 75 so as to keep it substantially constant while discharging
Liquid 70 in the supply channel 76 between the nozzle and the supply nozzle 6
Is detected by the pressure detecting unit 77, and the control unit C controls the rod 8 of the air cylinder 82 based on the detected value.
2a is controlled.

That is, in the bellows pump 8, the length of the flexible pipe 81 is adjusted by the pressing amount of the rod 82 a of the air cylinder 82, thereby changing the discharge pressure (liquid amount) of the resist liquid 70 pushed out from the pump 8. For example, when the amount of pressure on the rod 82a is increased and the flexible tube 81 is shortened, the discharge pressure of the resist liquid 70 discharged from the discharge hole 60 of the supply nozzle 6 to the surface of the wafer W increases accordingly. When the pressing amount of 82a is reduced, the discharge pressure of the resist liquid 70 decreases. The pressure in the supply flow path 76 is proportional to the discharge pressure of the resist liquid from the supply nozzle 6. When the pressure in the supply flow path 76 is large, the discharge pressure of the resist liquid increases, When the pressure is small, the discharge pressure becomes small.

Accordingly, the resist solution 7 in the supply flow path 76
The pressure of 0 is detected at a predetermined timing for example every second, rod 82a from the compressed air source 80 on the basis of the detected value by controlling the amount of air supplied to the air cylinder 82
By controlling the amount of pressing, the discharge pressure of the resist liquid 70 from the discharge holes 60 of the supply nozzle 6 can be controlled to be substantially constant.

Further, in this example, the air cylinder 82
The stroke amount L of the rod 82a is detected by the displacement meter 78 at a predetermined timing, for example, every one second. When the stroke amount L is abnormal based on the detected value, the switch of the alarm generation unit 79 is controlled by the control unit C. And informs you of the occurrence of an abnormality.

For example, as shown in FIG. 7, in order to obtain a constant pressure, the stroke displacement of the rod 82a of the air cylinder 82 is proportional to time. When there is an abnormality such as clogging, the stroke displacement amount deviates from the proportional curve. That is, when the discharge holes 60 are clogged, the discharge holes 6
Since the pressure in the supply flow path 76 increases due to the blockage of 0, the stroke displacement required to obtain the predetermined pressure is smaller than the set value, as shown by the dotted line in FIG.
Looking at this in relation to the discharge amount, as shown in FIG. 8, if the discharge pressure of the nozzle is constant, the discharge amount is constant, but when the nozzle is clogged, as shown by the dotted line in the figure. ,
The discharge amount decreases with time.

Therefore, a reference range of the time change of the stroke displacement of the rod 82a of the air cylinder 82 for obtaining a constant discharge pressure is obtained in advance, and the actual stroke of the rod 82a of the air cylinder 82 is measured by the displacement meter 78. The control unit C is configured to determine the amount L for each time, compare these values, and output an activation signal to the alarm unit 79 when the actual stroke amount L is out of the set stroke amount reference range. Accordingly, occurrence of any abnormality such as clogging of the discharge hole 60 of the supply nozzle 6 can be detected.

The resist liquid 70 thus supplied to the supply nozzle 6 through the supply flow path 76 is supplied from the discharge hole 60 to the surface of the wafer W at a substantially constant discharge pressure, and is supplied based on predetermined application conditions. The resist liquid 70 is applied by relatively moving the nozzle 6 and the wafer W. That is, for example, as shown in FIG. 3, the supply nozzle 6 is reciprocated in the X direction while intermittently feeding at a predetermined pitch in the Y direction, thus moving the supply nozzle 6 in a zigzag path relative to the wafer W, The resist liquid 70 is discharged from the nozzle 6 onto the wafer W, thereby forming a uniform liquid film on the circuit formation region 40 of the wafer W.

Here, the resist liquid 70 discharged from the supply nozzle 6 onto the wafer W and lands there, generates a certain spread in accordance with the viscosity thereof. By setting the pitch, a uniform and uniform resist film can be formed on the circuit formation region 40 of the wafer W.

After the application of the resist liquid in this manner, the ultrasonic vibrator 27 attached to the wafer suction table 22 is operated to apply the vibration in the ultrasonic band to the wafer W. As a result, agitation is applied to the applied resist liquid film, and the surface of the liquid film is planarized.

Thereafter, the mask member 4 to which the resist solution 70 has adhered is discharged to the mask member cleaning device 42 side, and then the wafer holder 2 is moved from the resist liquid application section R to the wafer load / unload section L. Then, the holding unit 24 is moved up and down to deliver the wafer W to a main arm (not shown).
The wafer W is unloaded from the resist coating device.

As described above, in the film forming apparatus of the present invention, the resist liquid 70 can be discharged from the supply nozzle 6 to the wafer W at a constant discharge pressure (discharge amount) as described above. Therefore, the resist solution 70 can be continuously discharged onto the wafer W with a constant line width without interruption, so that the amount of the resist solution 70 supplied on the wafer W It becomes substantially uniform over the entire surface, thereby improving the in-plane uniformity of the thickness of the resist film. At this time, the diameter of the discharge hole 60 of the supply nozzle 6 is 10 μm or more.
Since it is formed with a very small diameter of about 200 μm, it is possible to form a resist film having a small thickness and high uniformity.

Further, since the occurrence of an abnormal situation is notified by an alarm, the abnormal situation can be detected at an early stage, and such a situation can be dealt with quickly. In this example, the thinner solution is mixed in the resist solution 70. However, as described above, the discharge hole 60 of the supply nozzle 6 is formed to have a considerably small diameter, so that the thinner solution volatilizes and clogging occurs. It is easier. Therefore, for example, when the abnormal situation is clogging of the supply nozzle 6, the clogging can be found in the initial stage, the clogging is eliminated, and the resist solution 70 is again supplied from the supply nozzle 6 onto the wafer W. Can be continuously discharged at a constant line width.

If the detection of the occurrence of such an abnormal situation is delayed, the resist liquid 70 is supplied onto the wafer W from the clogged supply nozzle 6.
Cannot discharge the resist liquid 70 at a constant discharge pressure. For this reason, the in-plane uniformity of the thickness of the resist film is deteriorated, and the throughput of the coating process of the resist liquid is reduced.

In the initial stage of clogging, the supply nozzle 6
The clogging can be eliminated without performing cleaning of the nozzle 6 or simple cleaning can be performed, so that the number of times of cleaning the nozzle 6 and the total cleaning time can be reduced, and from this point the throughput can be improved. Is achieved.

Further, in this example, the filter 64 made of a PTFE film is provided in the supply nozzle 6 so as to close the flow path 66, so that the nozzle 6 can supply the resist solution 70 to the wafer W more stably. Can be. In other words, in the resist solution 70, bubbles having a size of about 5 μm may appear in the resist solution 70 due to pressure change or the like due to bending of the pipe. When the bubbles are present near the hole 60, the bubbles serve as a cushion, and the discharge pressure of the resist solution 70 decreases. When the bubbles are not crushed and disappear, the discharge pressure temporarily increases. The discharge pressure fluctuates.

On the other hand, if the filter 64 is provided, bubbles can be removed from the resist solution 70 by the filter 64, so that fluctuations in the discharge pressure of the resist solution 70 caused by bubbles can be suppressed, and a stable supply of the resist solution can be performed. Can be. At this time, in this example, since a PTFE membrane having a pore diameter of about 5 μm is used, pressure loss can be suppressed.

In this example, since a high-viscosity resist solution is diluted with a thinner solution in a mixing tank in a resist solution supply system, a high-viscosity resist solution which has been conventionally difficult to use can be used. it can. Thereby, the viscosity limitation of the resist liquid can be eliminated, and the versatility of this coating method can be enhanced.

At this time, the resist solution 70 whose viscosity has been adjusted in the mixing tank 73 is once sent to the buffer tank 74, from which it is supplied to the supply nozzle 6 by the bellows pump 8 equipped with a control system for the pressing force. Control is easy. That is, when the respective chemicals are directly supplied from the high-viscosity resist liquid tank 71 and the solvent tank 72 to the supply nozzle 6 without providing the mixing tank 73 and the buffer tank 74, the respective pumps P1 and P2 reduce the pressing force. This is because it is necessary to provide a control system, and in this case, since the respective pumps P1 and P2 must be synchronized, the control is troublesome.

Next, another example of the present invention will be described with reference to FIG. 9. In this example, the abnormality of the stroke of the rod 82a of the air cylinder 82 of the bellows pump 8 is detected, and when an abnormal value appears, the supply nozzle 6 This is a system for cleaning. For example, in this example, a cleaning unit 67 for cleaning the supply nozzle 6 is provided in the wafer load / unload unit L, and the slider 55 holding the supply nozzle 6 is configured to be able to move up and down by an elevating mechanism 68. . The cleaning unit 91 is configured to immerse the supply nozzle 6 in a cleaning liquid 69 for a predetermined time for cleaning, for example.
Is configured so that the operation is controlled by the nozzle / wafer driving unit 36.

The rod 82 of the air cylinder 82
The stroke amount L is detected by the displacement meter 78 at a predetermined timing, for example, every one second. When the stroke amount L deviates from a preset reference range based on the detected value, the control unit C controls the nozzle / wafer. The supply nozzle 6 is moved to the cleaning unit 67 via the drive unit 36, and the nozzle 6 is cleaned.

In such an example, the supply nozzle 6
Is performed, even if an abnormal situation such as clogging occurs, the abnormal situation can be smoothly resolved without bothering the operator.

Next, an example of a coating / developing apparatus in which the above-described developing apparatus is incorporated in a unit will be described with reference to FIGS.
1 will be described. In FIGS. 10 and 11, 9
Is a loading / unloading stage for loading / unloading a wafer cassette. For example, a cassette C containing 25 sheets is placed by, for example, an automatic transfer robot. A transfer arm 90 for the wafer W is provided in a region facing the loading / unloading stage 9 so as to be freely rotatable in X, Y directions and θ (rotation about a vertical axis). Further, behind the transfer arm 90, a coating / developing unit U1 is located on the right side, for example, as viewed from the loading / unloading stage 9, and heating / cooling is located on the left, front and rear sides. System units U2, U3, and U4 are arranged, respectively, and for transferring a wafer W between a coating / developing system unit and a heating / cooling system unit, for example, freely movable up and down, movable left and right, and back and forth. A wafer transfer arm MA rotatably arranged about a vertical axis is provided. However, in FIG. 11, the unit U2 and the wafer transfer arm MA are not drawn for convenience.

In the coating / developing system unit, for example, two developing units 91 are provided in an upper stage, and a coating unit 92 provided with two film forming apparatuses is provided in a lower stage. In a heating / cooling system unit, a heating unit, a cooling unit, a hydrophobizing unit, and the like are provided above and below.

The above-described portion including the coating / developing system unit and the heating / cooling system unit is referred to as a clean track, and the back side of the clean track is exposed through an interface unit 93 through an exposure apparatus. 94 is connected. The interface unit 93 can be moved up and down, for example.
The wafer W is transferred between the clean track and the exposure device 94 by a wafer transfer arm 95 configured to be movable left / right, forward / backward, and rotatable about a vertical axis.

The flow of wafers in this apparatus will be described. First, a wafer cassette C containing a wafer W is loaded into the loading / unloading stage 9 from the outside, and a wafer transporting arm is loaded.
The wafer W is taken out of the cassette C by the
The wafer is transferred to the wafer transfer arm MA via a transfer table, which is one of the shelves of the heating / cooling unit U3. Next, after a hydrophobic treatment is performed in the processing section of one shelf of the unit U3, a resist liquid is applied by the application unit 92 to form a resist film. After being heated by the heating unit, the wafer W coated with the resist film is sent to an exposure device 94 via an interface unit 93, where exposure is performed via a mask corresponding to the pattern.

Thereafter, the wafer W is heated by the heating unit, cooled by the cooling unit, and subsequently cooled by the developing unit 9.
The resist film is sent to the developing device 1 and subjected to a development process, thereby forming a resist mask. Thereafter, the wafer W is returned to the cassette C on the loading / unloading stage 9.

As described above, according to the present invention, the pressing amount of the bellows pump is controlled based on the pressure in the supply flow path 76 between the bellows pump 8 and the supply nozzle 6, and the pressure is supplied from the supply nozzle 6 to the surface of the wafer W. A configuration for controlling the discharge amount of the supplied resist solution, a configuration for activating the alarm generating section 79 when the pressing amount of the bellows pump 8 is out of a preset reference range, and a configuration for controlling the pressing of the bellows pump 8 When the amount deviates from a preset reference range, the structure for cleaning the supply nozzle 6 and the structure for using the supply nozzle 6 including the filter 74 for removing bubbles from the resist solution are combined. This may be done or may be configured separately.

Instead of a mixing tank 73 for diluting a high-viscosity resist solution with a thinner solution, an in-line mixer called a static mixer is provided in the resist solution supply system, where the high-viscosity resist solution and the thinner solution are mixed. Then, a low-viscosity resist solution having a predetermined viscosity may be adjusted. In this in-line mixer, a negitator plate turning right 90 degrees and a negitator plate turning left 90 degrees are alternately mounted in a pipe to form a swirling flow path in the pipe. When a predetermined amount of a high-viscosity resist solution and a predetermined amount of a thinner solution are sent,
These solutions are stirred and mixed while flowing in the channel,
A low-viscosity resist solution having a predetermined viscosity is adjusted. When an in-line mixer is provided instead of the mixing tank 73 in this manner, a pump for sending the low-viscosity resist solution from the mixing tank 73 to the buffer tank 74 does not need to be provided. Can be achieved.

Further, in the resist solution supply system, a mixing tank 73 for diluting a high-viscosity resist solution with a thinner solution is not provided. The liquid may be supplied to the supply nozzle 6 without using the buffer tank 74 and using the bellows pump 8 that directly controls the pressing force from the mixing tank 74. In this case, for example, a predetermined amount of the high-viscosity resist solution and a thinner solution are supplied to the mixing tank 73 to adjust the predetermined-viscosity resist solution, and then the high-viscosity resist solution and the thinner solution are supplied thereto. In this state, the resist solution may be sent downstream by the bellows pump 8.

Further, a high-viscosity resist solution and a solvent may be directly supplied to the supply nozzle 6 by using bellows pumps for controlling the pressing force. In this case, the respective bellows pumps are synchronized. While being controlled.

Further, the pressing pump for performing the pressing force control of the present invention is not limited to the bellows pump, but may be, for example, a diaphragm pump or a rotary pump. The pressing member is not limited to an air cylinder. The rod may be pressed by a motor or the like.

Further, in the present invention, the bellows pump 8
Instead of providing the filter device 75 between the nozzle and the supply nozzle 6, a filter device 75 may be provided between the buffer tank 74 and the bellows pump 8, and in this case, bubbles generated in the buffer tank 74 may be removed. Since it can be removed by the filter device 75, it is possible to suppress the bubbles from entering the bellows pump 8, which is effective.

Further, in the above-described example, the resist solution was used as an example of the processing liquid. However, the present invention is not limited to this. For example, an interlayer insulating film material, a high conductive material, a low dielectric material, a ferroelectric The present invention can be applied to a body material, a wiring material, an organic metal material, a metal paste such as a silver paste, and the like.
Further, the filter 74 provided in the supply nozzle 6 is not limited to the PTFE film, but may be a resin such as nylon. The substrate is not limited to a semiconductor wafer, but may be an LCD substrate or an exposure mask. Further, the supply nozzle 6 and the wafer W are relatively moved. For example, the supply nozzle 6 may be fixed and the wafer W may be driven in the XY directions. Also, the drive mechanism of the supply nozzle 6 and the wafer holder 2 is not limited to the above example, and a belt drive mechanism or the like may be used, for example. Here, substantially horizontal in the present invention includes a substantially horizontal state.

[0080]

According to the first aspect of the present invention, the pressing amount of the pressing member of the pressing pump is controlled based on the pressure in the flow path of the processing liquid between the pressing pump and the supply nozzle. Therefore, the discharge amount of the processing liquid is uniform throughout the processing, and a liquid film having a stable film thickness can be formed.

According to the invention of claim 2, an abnormality such as clogging of the supply nozzle can be detected at an early stage.
According to the invention, when an abnormality such as clogging of the supply nozzle occurs, the supply nozzle can be quickly cleaned without bothering the operator.

According to the fourth aspect of the invention, fluctuations in the discharge pressure of the processing liquid due to the presence of bubbles contained in the processing liquid are suppressed, and the processing liquid can be stably supplied to the substrate. Thus, the uniformity of the liquid film thickness can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a film forming apparatus of the present invention.

FIG. 2 is a plan view showing the film forming apparatus.

FIG. 3 is a perspective view for explaining a coating path of a resist liquid.

FIG. 4 is a configuration diagram for describing a resist liquid supply system.

FIG. 5 is a cross-sectional view for explaining a bellows pump.

FIG. 6 is a cross-sectional view illustrating a supply nozzle.

FIG. 7 shows a time change of the stroke amount of the bellows pump,
FIG. 7 is a characteristic diagram showing a change over time in a discharge pressure of a resist liquid from a supply nozzle.

FIG. 8 is a characteristic diagram showing a temporal change of a discharge amount of a resist liquid from a supply nozzle.

FIG. 9 is a configuration diagram showing still another example of a resist liquid supply system.

FIG. 10 is a plan view showing a coating and developing apparatus provided with the film forming apparatus of the present invention.

FIG. 11 is a schematic perspective view showing the coating and developing apparatus.

FIG. 12 is a side view showing a conventional resist liquid coating apparatus.

FIG. 13 is a plan view showing a one-stroke writing method of applying a resist solution.

FIG. 14 is a configuration diagram showing a resist liquid supply system.

[Explanation of symbols]

 W Semiconductor wafer 2 Wafer holder 3 Frame 4 Mask member 5 Top plate 5a Slit 6 Supply nozzle 60 Discharge hole 64 Filter 69 Washing unit 71 High viscosity resist liquid tank 72 Solvent tank 73 Mixing tank 74 Buffer tank 76 Supply flow path 77 Pressure detection Part 78 Displacement gauge 79 Alarm generating part 8 Bellows pump 82 Air cylinder 82a Rod

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[Procedure amendment]

[Submission date] February 1, 2000 (2000.2.1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 7

FIG. 8

FIG.

FIG. 13

FIG. 3

FIG. 4

FIG. 9

FIG. 14

FIG. 5

FIG. 6

FIG. 11

FIG. 10

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukihiko Ezaki 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Tokyo Inside the Electron Kyushu Co., Ltd. Inside Electron Kyushu Kumamoto Office (72) Inventor Nohisa Koga 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Tokyo Electron Kyushu Corporation Kumamoto Office, 2655 No. 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Tokyo Electron Kyushu Co., Ltd.Kumamoto Office (72) Inventor Hirofumi Okuma 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Tokyo Electron Kyushu Corporation Kumamoto Office, 2655 Address Tokyo Electron Kyushu Kuma Co., Ltd. In-house F-term (Reference) 2H025 AA18 AB16 EA04 EA05 EA10 4F041 AA06 AB01 BA05 BA31 BA34 BA56 4F042 AA07 AB00 BA07 BA08 BA12 BA15 BA16 CB02 CB03 CB25 CC04 CC08 DH02 5F045 AF01 BB02 EN02 EB10 EM02 EB02 EM02 EB02 HA25 5F046 JA02

Claims (8)

[Claims] 1. A film forming apparatus that discharges a processing liquid from a supply nozzle onto a surface of a substrate held substantially horizontally by a substrate holding unit and forms a liquid film of the processing liquid on the surface of the substrate. A pump body for sending the liquid to the supply nozzle, and a pressing member for pressing the pump body, the processing liquid is sent into the pump body from the upstream side by pulling the pressing member, by pressing the pressing member A processing liquid is sent to the downstream side from the pump body, and a pressing pump in which the amount of the processing liquid sent to the downstream is adjusted by the pressing amount of the pressing member; and a processing liquid between the pressing pump and the supply nozzle. A pressure detecting unit that detects a pressure in the flow path; and a control unit that controls a pressing amount of a pressing member of the pressing pump based on a detection value from the pressure detecting unit. Between nozzles Controlling the amount of pressing of the pressing member of the pressing pump based on the pressure in the flow path of the processing liquid, and controlling the discharge amount of the processing liquid supplied from the supply nozzle to the substrate surface. Membrane equipment. 2. A film forming apparatus which discharges a processing liquid from a supply nozzle onto a surface of a substrate held substantially horizontally by a substrate holding part and forms a liquid film of the processing liquid on the surface of the substrate, A pump main body and a pressing member for feeding the liquid to the supply nozzle are provided. The processing liquid is fed into the pump main body from the upstream side by pulling the pressing member, and the downstream side from the pump main body by pressing the pressing member. The processing liquid is sent out, and a pressing pump in which the amount of the processing liquid sent downstream is adjusted by the pressing amount of the pressing member, and a displacement meter for detecting the pressing amount of the pressing member of the pressing pump, A control unit that controls the operation of an alarm generation unit based on a detection value from the displacement meter, wherein the alarm is generated when a pressing amount of a pressing member of the pressing pump deviates from a preset reference range. Deposition apparatus characterized by actuating a. 3. A film forming apparatus that discharges a processing liquid from a supply nozzle onto a surface of a substrate held substantially horizontally by a substrate holding unit and forms a liquid film of the processing liquid on the surface of the substrate. A pump main body and a pressing member for feeding the liquid to the supply nozzle are provided. The processing liquid is fed into the pump main body from the upstream side by pulling the pressing member, and the downstream side from the pump main body by pressing the pressing member. The processing liquid is sent out, and a pressing pump in which the amount of the processing liquid sent downstream is adjusted by the pressing amount of the pressing member, and a displacement meter for detecting the pressing amount of the pressing member of the pressing pump, A cleaning unit for cleaning the supply nozzle; a drive mechanism for moving the supply nozzle to the cleaning unit; and a control unit for controlling operation of the drive mechanism based on a detection value from the displacement meter. , When the pressing amount of the pressing member of the pressing pump deviates from a preset reference range, the supply nozzle is moved to a cleaning unit by the driving mechanism, and the supply nozzle is cleaned. apparatus. 4. A film forming apparatus for discharging a processing liquid from a supply nozzle onto a surface of a substrate held substantially horizontally by a substrate holding unit and forming a liquid film of the processing liquid on the surface of the substrate, wherein the supply nozzle is A processing liquid flow path; a discharge port connected to the processing liquid flow path, for discharging the processing liquid in a linear shape having a small diameter; and a processing hole provided to close the processing liquid flow path. A film forming apparatus comprising: a filter for removing bubbles from a liquid. 5. The film forming apparatus according to claim 4, wherein said filter is made of a porous resin. 6. A processing liquid is discharged from a supply nozzle while relatively driving the substrate holding unit and a supply nozzle along a surface direction of a substrate, and a liquid film of the processing liquid is formed on the surface of the substrate. The film forming apparatus according to claim 1, 2, 3, 4, or 5, wherein 7. A mixing tank for adjusting a low-viscosity processing liquid by mixing a high-viscosity processing liquid and a solvent of the processing liquid, wherein the viscosity-adjusted processing liquid in the mixing tank is provided. 7. The film forming apparatus according to claim 1, wherein liquid is sent to a supply nozzle by a pressurizing pump. 8. The film forming apparatus according to claim 1, wherein the processing liquid is a resist liquid.