JP2003145017A - Coating method and coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method and a coating apparatus in which a coating film such as a resist film is formed with high film thickness precision and film thickness uniformity. SOLUTION: The coating apparatus is equipped with a substrate holding member 51 for holding a substrate W to be processed nearly horizontal, a motor 52 for rotating the substrate holding member 51, a coating liquid discharge nozzle 90 for supplying a coating liquid to the center of the substrate W to be processed, a pump 97 for discharging the coating liquid from the nozzle 90, a valve 94 provided in the pipe line 91, a valve opening detection means 94a for detecting a signal showing that the valve 94 is opened and a control means 100 for starting to drive the motor 52 based on the detection signal inputted to the valve opening detection means 94a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating processing method and a coating processing apparatus for coating a substrate such as a semiconductor wafer with a coating liquid such as a resist.

[0002]

2. Description of the Related Art For example, in a semiconductor device manufacturing process, a resist solution is supplied to the surface of a semiconductor wafer (hereinafter simply referred to as a "wafer") to form a resist film, and a predetermined resist is applied to the resist-coated wafer. The resist pattern is formed as a mask for forming a predetermined pattern by a so-called photolithography technique in which the exposure pattern formed on the resist film of the wafer is developed after performing the exposure process corresponding to the pattern. In the resist coating process of the above steps, the spin coating method is often used as a method for uniformly coating the resist liquid on the wafer surface.

FIG. 13 shows an outline of this spin coating method. For example, in a state where the wafer W is fixedly held by vacuum adsorption by the spin chuck 141, while rotating the wafer W together with the spin chuck 141 by a rotation driving unit (not shown), the surface of the wafer W is removed from the resist nozzle 142 arranged above the wafer W. A resist solution is dropped in the center. The dropped resist solution spreads outward in the radial direction of the wafer W due to the centrifugal force, and a resist film is formed on the entire surface of the wafer W. After that, the dropping of the resist solution is stopped, the rotation of the wafer is continued, and the excess resist solution on the surface of the wafer W is shaken off to adjust the film thickness and dry it.

By the way, in order to form a resist pattern with high accuracy, it is necessary to form a resist film with a uniform film thickness over the entire surface of the wafer. In addition, it is important to strictly control the resist drop time and the timing between the resist drop and the wafer rotation.

Conventionally, the film thickness and the film thickness distribution of the resist film are managed by controlling them by software of the apparatus.

[0006]

However, the actual timing of discharging the resist solution is not always the same as the timing managed by software, and therefore the control may be slightly deviated from the optimum condition. is there. In recent years, semiconductor devices have become more and more miniaturized, and the demand for resist film thickness accuracy and film thickness uniformity has become extremely high. There is a possibility that accuracy and film thickness uniformity may deviate from the required range.

The present invention has been made in view of the above circumstances, and provides a coating processing method and a coating processing apparatus capable of forming a coating film such as a resist film with high film thickness accuracy and film thickness uniformity. The purpose is to

[0008]

In order to solve the above-mentioned problems, in the first aspect of the present invention, the coating liquid is discharged to substantially the center of the substrate to be processed and the substrate to be processed is rotated to treat the coating liquid. A coating treatment method for forming a coating film by spreading it radially outward of a substrate, wherein a valve provided in a pipe for supplying the coating liquid to a coating liquid discharge nozzle is opened when the coating liquid is discharged. And a coating process is controlled based on the detected signal.

According to a second aspect of the present invention, the coating liquid is discharged to approximately the center of the substrate to be processed and the substrate to be processed is rotated to spread the coating liquid radially outward of the substrate to be processed to form a coating film. And a step of sending a drive signal to a pump for discharging the coating liquid from the coating liquid discharge nozzle, and sending an open signal to a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle. A coating method comprising: detecting a signal indicating that the valve has been opened; and rotating the substrate to be processed based on the signal indicating that the valve has been opened. I will provide a.

According to a third aspect of the present invention, the coating liquid is discharged to the approximate center of the substrate to be processed and the substrate to be processed is rotated to spread the coating liquid radially outward of the substrate to be processed to form a coating film. And a step of sending a drive signal to a pump for discharging the coating liquid from the coating liquid discharge nozzle, and sending an open signal to a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle. A step of detecting a signal indicating that the valve has been opened, a step of starting rotation of the substrate to be processed based on the signal indicating that the valve has been opened, and a step of opening the valve. And a step of controlling the discharge end time of the coating liquid based on the signal shown.

According to a fourth aspect of the present invention, the coating liquid is discharged to approximately the center of the substrate to be processed and the substrate to be processed is rotated to spread the coating liquid radially outward of the substrate to be processed to form a coating film. Which is a coating processing apparatus for holding a substrate to be processed substantially horizontally, a motor for rotating the substrate holding member, and a coating liquid at a substantially center of the substrate to be processed held by the substrate holding member. A coating liquid discharge nozzle for supplying the liquid, a pump for discharging the coating liquid from the coating liquid discharge nozzle, a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle, and the valve being opened. Coating device comprising: an open detection means for detecting a signal indicating that the application signal is detected; and a control means for receiving the detection signal of the open detection means and starting driving of the motor based on the detection signal. processing To provide a location.

According to a fifth aspect of the present invention, the coating liquid is discharged to substantially the center of the substrate to be processed and the substrate to be processed is rotated to spread the coating liquid radially outward of the substrate to be processed to form a coating film. Which is a coating processing apparatus for holding a substrate to be processed substantially horizontally, a motor for rotating the substrate holding member, and a coating liquid at a substantially center of the substrate to be processed held by the substrate holding member. A coating liquid discharge nozzle for supplying the liquid, a pump for discharging the coating liquid from the coating liquid discharge nozzle, a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle, and the valve being opened. Open detection means for detecting a signal indicating that, the detection signal of the open detection means is input, based on the detection signal, the drive of the motor is started, and the discharge end time of the coating liquid and the motor Providing a coating apparatus characterized by a control means for controlling the stop point of the movement.

According to the present invention, when the coating liquid is discharged, a signal indicating that the valve provided in the pipe for supplying the coating liquid to the coating liquid discharge nozzle is opened is detected, and the signal is detected based on the signal. Since the coating process is controlled, various conditions can be controlled after grasping the time when the coating liquid is actually discharged, and a coating film such as a resist film can be formed with high film thickness accuracy and film thickness uniformity. it can.

That is, when the coating liquid such as the resist liquid is discharged, the valve provided in the nozzle is operated, but the air operation valve normally used as such a valve is at the time when the open signal is input. Since the time from the opening to the actual open state is not constant and varies depending on individual valve differences and installation conditions, even if the coating liquid discharge timing is strictly controlled by software, the actual coating liquid discharge timing There may be a shift. Therefore, in the present invention, by detecting a signal indicating that the valve is actually opened, the timing of discharging the coating liquid can be controlled with high accuracy, and the coating film can be formed with high film thickness accuracy and film thickness uniformity. can do.

Specifically, as in the second and fourth aspects, a signal indicating that the valve has been opened is detected, and the substrate to be processed is controlled to rotate based on the signal. As a result, it is possible to prevent inconveniences such as the rotation speed of the substrate to be processed being too high at the time when the coating liquid is ejected, which causes a film thickness variation.

Further, as in the third and fifth aspects, by further controlling the discharge end time of the coating liquid based on the signal indicating that the valve has been opened, the actual coating liquid can be obtained. The ejection time can be made constant, and the film thickness accuracy and film thickness uniformity of the coating film can be further improved.

In this case, when controlling the discharge end time of the coating liquid, from the time when the opening signal is sent to the valve and the valve is actually opened to the time when the signal indicating the opening is detected. It is preferable to control the time when the driving of the pump is stopped and the time when the valve is closed based on the delay time. Thereby, the film thickness can be controlled with higher accuracy. At this time, the drive stop time of the pump can be controlled based on the coating liquid discharge rate and the delay time grasped when the coating process is performed on the conventional substrate to be processed. As a result, the pump can be easily controlled. Further, it is possible to control so that the rotation of the substrate to be processed is reduced (that is, the motor is stopped) after a preset time has elapsed after the signal indicating that the valve has been opened is detected, or the valve is closed. It is also possible to detect a signal indicating that and to control the rotation of the substrate to be processed to be reduced based on the signal.

Further, in the present invention, as the signal indicating that the valve is opened, the signal detected when the coating process is performed on the conventional substrate to be processed can be used. This makes it possible to adjust the rotation speed of the substrate to be processed when the coating liquid is discharged.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic plan view showing a resist coating / developing processing system equipped with a resist coating processing unit for carrying out the coating processing method of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a rear view thereof.

The resist coating and developing system 1 is
A cassette station 10, which is a transfer station,
A processing station 11 having a plurality of processing units;
An interface unit 12 for transferring the wafer W between the processing station 11 and an exposure device (not shown) provided adjacent to the processing station 11.

In the cassette station 10, a plurality of wafers W to be processed are loaded into the wafer cassette CR in units of, for example, 25 wafers, and loaded into or unloaded from another system. Wafer cassette CR and processing station 1
This is for carrying the wafer W to and from 1.

In this cassette station 10, as shown in FIG. 1, a mounting table 2 on which a cassette C is mounted.
A plurality of (four in the figure) positioning protrusions 20a are formed on the substrate 0 along the X direction in the figure, and the wafer cassettes CR are aligned at the positions of the protrusions 20a with the respective wafer entrances and exits facing the processing station 11 side. It can be placed on. In the wafer cassette CR, the wafers W are arranged in the vertical direction (Z direction). The cassette station 10 also has a wafer transfer mechanism 21 located between the mounting table 20 and the processing station 11. The wafer transfer mechanism 21 has a wafer transfer arm 21a that is movable in the cassette arrangement direction (X direction) and the wafer arrangement direction of the wafers W therein (Z direction). Wafer cassette CR can be selectively accessed. The wafer transfer arm 21a is configured to be rotatable in the θ direction, and is included in an alignment unit (ALI) belonging to a _third processing unit group G ₃ on the processing station 11 side described later.
M) and extension unit (EXT) are also accessible.

The processing station 11 is provided with a plurality of processing units for carrying out a series of steps for coating / developing the wafer W, and these processing units are arranged in multiple stages at predetermined positions. The wafers W are processed one by one. As shown in FIG. 1, the processing station 11 has a transfer path 22a in the center thereof, a main wafer transfer mechanism 22 is provided in the transfer path 22a, and all the processing units are arranged around the transfer path 22a. . The plurality of processing units are divided into a plurality of processing unit groups, and each processing unit group includes a plurality of processing units arranged in multiple stages along the vertical direction.

As shown in FIG. 3, the main wafer transfer mechanism 22 is equipped with a wafer transfer device 46 inside the cylindrical support 49 so as to be vertically movable (Z direction). The cylindrical support 49 is rotatable by a rotational driving force of a motor (not shown), and the wafer transfer device 4 is accordingly rotated.
6 is also rotatable integrally.

The wafer transfer device 46 includes a plurality of holding members 48 that are movable in the front-rear direction of the transfer base 47, and these holding members 48 realize the transfer of the wafer W between the processing units. .

Further, as shown in FIG. 1, in this embodiment, four processing unit groups G ₁ , G ₂ , G ₃ ,
G ₄ is arranged around the transport path 22a, and the processing unit group G ₅ can be arranged as necessary.

Of these, the first and second processing unit groups G ₁ and G ₂ are in front of the system (front side in FIG. 1).
The third processing unit group G ₃ is arranged in parallel on the side, the third processing unit group G ₃ is arranged adjacent to the cassette station 10, and the fourth processing unit group G ₄ is arranged adjacent to the interface section 12. Further, the fifth processing unit group G ₅ can be arranged on the back surface.

In the first processing unit group G ₁ , the cup C
A resist coating processing unit (COT) that mounts the wafer W on a spin chuck (not shown) in P to coat the resist on the wafer W, and a developing processing unit (DEV that similarly develops the resist pattern in the cup CP). ) Are stacked in two steps in order from the bottom. Second processing unit group G
₂ Similarly, the resist coating unit (COT) and developing unit (DEV) are two-tiered in order from the bottom as two spinner-type processing units.

In the third processing unit group G ₃ , as shown in FIG. 3, a plurality of oven-type processing units for stacking the wafer W on the mounting table SP and performing predetermined processing are stacked. That is, the adhesion unit (A) that performs a so-called hydrophobic treatment for improving the fixability of the resist.
D), an alignment unit (ALIM) for aligning the wafer W, an extension unit (EXT) for loading / unloading the wafer W, a cooling unit (COL) for cooling processing, before and after exposure processing, and further for development. Four hot plate units (HP) for heating the wafer W after the processing are stacked in eight stages in order from the bottom. Alignment unit (ALIM)
Alternatively, a cooling unit (COL) may be provided and the cooling unit (COL) may have an alignment function.

Also in the fourth processing unit group G ₄ , oven type processing units are stacked in multiple stages. That is, a cooling unit (COL), an extension / cooling unit (EXTCOL) that is a wafer loading / unloading unit equipped with a cooling plate, an extension unit (EXT), a cooling unit (COL), and four hot plate units (HP) are located below. In order from 8
It is stacked in columns.

When the fifth processing unit group G ₅ is provided on the back side of the main wafer transfer mechanism 22, it can be moved laterally along the guide rail 25 when viewed from the main wafer transfer mechanism 22. . Therefore, even when the fifth processing unit group G ₅ is provided, the space is secured by sliding the fifth processing unit group G ₅ along the guide rail 25, so that maintenance work can be easily performed from the rear side with respect to the main wafer transfer mechanism 22. Can be done.

The interface section 12 has the same length in the depth direction (X direction) as that of the processing station 11. As shown in FIGS. 1 and 2, the interface section 12 has a portable front surface. Pick-up cassette CR
The stationary buffer cassette BR is arranged in two stages, the peripheral exposure device 23 is arranged at the back surface, and the wafer transfer mechanism 24 is arranged at the central part. The wafer transfer mechanism 24 has a wafer transfer arm 24a. The wafer transfer arm 24a moves in the X and Z directions to access both cassettes CR, BR and the peripheral exposure device 23. ing. Further, the wafer transfer arm 24a is rotatable in the θ direction, and an extension unit (EXT) belonging to the fourth processing unit group G ₄ of the processing station 11 or a wafer transfer table of the adjacent exposure apparatus side. It is also accessible (not shown).

In the resist coating / developing processing system 1 thus constructed, the unprocessed wafers W are taken out one by one from the wafer cassette CR by the wafer transfer mechanism 21 and carried into the alignment unit (ALIM) of the processing station 11. . Next, the wafer W positioned here is carried out by the main wafer transfer mechanism 22 and carried into the adhesion unit (AD) to be subjected to the adhesion processing. After the completion of this adhesion process, the wafer W is unloaded by the main wafer transfer mechanism 22 and transferred to the cooling unit (COL) where it is cooled. Next, the wafer W is transferred to a resist coating processing unit (COT) for resist coating, and prebaking is performed by a hot plate unit (HP), and the interface unit 12 is passed through an extension cooling unit (EXTCOL). Then, the wafer is transferred to the adjacent exposure apparatus by the wafer transfer mechanism 24. After that, the wafer W that has been subjected to the exposure processing by the exposure apparatus is transferred to the processing station 11 by the wafer transfer mechanism 24 via the interface section 12 and the extension unit (EXT). In the processing station 11, the main wafer transfer mechanism 22 transfers the wafer W to the hot plate unit (HP) for post exposure processing, and then to the developing unit (DEV) for development processing, and then the hot plate unit. (HP) post bake process, cooling unit (COL)
After cooling in the extension unit (EX
It is conveyed to the cassette station 10 via T). The wafer W, which has been subjected to the predetermined processing as described above, is stored in the wafer cassette CR by the wafer transfer mechanism 22.

Next, a resist coating processing unit (COT) for carrying out the coating processing method of the present invention will be described with reference to FIG.
The description will be made with reference to FIG. The resist coating processing unit (COT) has a casing 50 having an opening 50a into which the holding member 48 of the main wafer transfer mechanism 22 enters, and a cup CP, which is a container for housing the wafer W, is provided therein. Wafer W in the cup
Spin chuck 51 for holding horizontally by vacuum suction
Is provided. The spin chuck 51 can be rotated by a drive motor 52 such as a pulse motor provided below the cup CP, and its rotation speed can also be arbitrarily controlled. An exhaust pipe 53 is connected to a portion near the center of the bottom portion of the cup CP, and a drain pipe 54 is connected to a portion from the outside. Then, the gas in the cup CP is exhausted from the exhaust pipe 53, and the resist liquid and the solvent scattered during the coating process are exhausted from the drain pipe 54. The spin chuck 51
Can be moved up and down by a lifting mechanism such as an air cylinder (not shown).

A jet head 60 is provided above the spin chuck 51 so as to be movable between a position directly above the spin chuck 51 and a retracted position. The jet head 60 is connected to a drive mechanism 70 via an arm 61. The drive mechanism 70 moves in the X, Y and Z directions shown in FIGS. 4 and 5. The spout 60 is an arm 6
It is removable with respect to 1.

The spray head 60 has a base member 62 and supplies a solvent capable of dissolving the resist solution to a solvent supply nozzle 80.
And a resist solution supply nozzle 90 for supplying a resist solution, which is a coating solution, are attached to the base member 62 in a state of being brought close to each other. The solvent in which the resist solution can be dissolved improves the wettability of the resist solution to reduce the consumption of the resist, and may be the solvent of the resist solution, but it is not limited thereto and can dissolve the resist coating solution. Any material may be used, and a thinner is typically used.

A resist liquid supply nozzle 90 is provided on the jet head 60.
A tube 65 that circulates a temperature control fluid to control the temperature of the resist solution discharged from the device to be constant.
a, 65b, and tubes 66a, 66b for circulating a temperature adjusting fluid to adjust the temperature of the solvent discharged from the solvent supply nozzle 80 to be constant. The tube 65a is a resist solution supply nozzle 90.
The pipe 65b is provided around the continuous pipe to form a forward path, and the tube 65b forms a return path. Also, the tube 66
“A” is provided around the pipe continuous with the solvent supply nozzle 80 to form an outward path, and the tube 66b forms a return path.

The resist solution supply nozzle 90 is communicated with a resist solution tank 92 containing the resist solution through a resist solution supply pipe 91. A suck back valve 93, an air operation valve 94, a bubble removing mechanism 95 for separating and removing bubbles in the resist solution, a filter 96, and a bellows pump 97 are provided in this resist solution supply pipe 91 in this order from the downstream side. There is. The bellows pump 97 includes an expandable / contractible main body 97 a, a ball screw mechanism 98, and a stepping motor 99. The ball screw mechanism 98 and the stepping motor 99 are included in the main body 9.
7 a of the drive unit. The ball screw mechanism 98 has a screw 98a whose one end is attached to one end of the bellows pump.
And a nut 98b screwed to the screw, and the main body 97a is expanded and contracted by rotating the nut 98b by the stepping motor 99 to linearly move the screw 98a. Then, at the same time when the air operation valve 94 is opened, the main body 97a of the bellows pump 97 is contracted to discharge a predetermined amount of resist solution onto the wafer W via the resist solution supply pipe 91 and the resist solution supply nozzle 90. It The bellows pump 97 makes it possible to control an extremely small amount of resist solution supplied.
The air operation valve 94 is provided with an open / close detector 94a that detects the open / close state of the air operation valve 94.

As shown in FIG. 5, a holding portion 55 capable of holding four jet nozzles 60 having basically the same structure is provided on the outer portion of the cup CP in the casing 50. The holding portion 55 is provided with an insertion portion (not shown) for placing the nozzle opening of each nozzle in a solvent atmosphere so as not to dry and solidify the nozzle opening of each nozzle. Each spout 60
Can be attached to the tip of the arm 61 by the attachment portion 63, and different types of resist liquids can be supplied. Then, one selected from these is attached to the arm 61, and the holding portion 55 is attached.
Taken from. As described above, the arm 61 can be three-dimensionally moved by the drive mechanism 70, that is, in the X, Y, and Z directions, and the ejection nozzle 60 taken out from the holding portion 55 and attached to the arm 61 is used for processing. Wafer W
Is moved to a predetermined position directly above.

In the example of FIG. 5, the solvent supply nozzle 80 and the resist solution supply nozzle 90 are attached to each of the ejection heads 60, but the invention is not limited to this, and only the resist solution supply nozzle 90 is attached to each ejection head 60. , Solvent supply nozzle 80
May be provided in common to the resist solution supply nozzles 90 of these nozzles 60. In this case, the solvent supply nozzle 8
For this purpose, a separate driving arm may be provided, or the solvent supply nozzle 80 may be attached to the arm 61 in advance and moved integrally with one selected nozzle head 60.

When applying the resist liquid, the timing of the rotation of the wafer W and the discharge of the resist liquid and the resist liquid discharge time are important, so the controller 100 is provided to control them. This controller 100
Is a drive motor 52 for rotating the spin chuck 51,
The air operation valve 94 and the bellows pump 97 are controlled, and commands for turning on / off the rotation and rotation speed are transmitted to the drive motor 52, and an open signal is output to the normally closed air operation valve 94. Bellows pump 97 stepping motor 99
The command of ON / OFF and the discharge rate is transmitted to. Further, a signal from the open / close detector 94a is input to the controller 100, and the coating process of the resist liquid is controlled based on this signal.

The air operation valve 94 is, for example, as shown in FIG. 6, a container 111, a valve body 112 provided therein so as to be able to move up and down, and a valve seat 1 below the valve body 112.
13 and a resist solution flow section 114. The resist liquid flow section 114 has a resist liquid flow passage 115 connected to the resist liquid supply pipe 91, and the resist liquid flow inlet 115 extends from the resist liquid flow passage 115 to the valve seat 113.
6 and the resist solution outlet 117 are open. Then, the flow of the resist solution is blocked when the valve body 112 is in contact with the valve seat 113 in the closed state, and the resist solution flows in the open state where the valve body 112 is separated from the valve seat 113. A partition member 118 that vertically partitions the inside of the container 111 is provided so as to be vertically movable, and the valve body 112 is integrally provided so as to hang from the partition member 118. Then, from the air introduction port 119 provided on the side wall of the container 111, the air introduction pipe 12
When air is introduced into the container 111 via 0, the partition member 118 moves upward, and the valve body 112 moves upward accordingly, so that the valve 94 is opened. Further, the container 111 is provided with an air discharge port 124, and the air discharge port 124 is provided at this air discharge port 124.
When the valve 25 is connected and the valve 94 is closed, the air supply is stopped and a solenoid valve (not shown) on the discharge side is operated to discharge the air in the container 111. A coil spring 121 for urging the partition member 118 downward is provided in an upper portion of the partition member 118 inside the container 111, and when air is not introduced into the container 111 and when air is discharged as described above. Valve 9
4 has a normally closed structure in which it is in a closed state.
A solenoid valve 122 is provided in the air introducing pipe 120, and air is introduced into the container 111 by opening the solenoid valve 122. Then, an open signal of the air operation valve 94 from the controller 100 is output to the solenoid valve 122, and based on this signal, the solenoid valve 122 is opened to introduce air, and the air operation valve 94 is opened.

The open / close detector 94a has a light emitting element 94a ₁ and a light receiving element 94a ₂ provided in the container 111, and when the valve body 112 rises to block light,
It is detected that the air operation valve 94 is opened.

Although the controller 100 actually controls other members related to the resist solution coating process, such as the suck back valve 93 and a solvent supply system (not shown), the description thereof is omitted here. Further, the suck back valve 93 draws back the resist liquid remaining on the inner wall of the front end of the resist liquid supply nozzle 90 due to surface tension into the resist liquid supply nozzle 90 after discharging the resist liquid from the resist liquid supply nozzle 90. To prevent the residual resist solution from solidifying.

Next, the operation and control of the resist solution coating process in the resist coating unit (COT) thus constructed will be described with reference to the flowchart of FIG.

When the holding member 48 of the main wafer transfer mechanism 22 transfers the wafer W through the opening 50a of the casing 50 to just above the cup CP in the resist coating unit (COT), the wafer W is illustrated. Vacuum suction is performed by the spin chuck 51 that has been lifted by the lifting mechanism. The main wafer transfer mechanism 22 causes the spin chuck 51 to vacuum-adsorb the wafer W, and then the holding member 48.
The wafer W to the resist coating processing unit (COT) by pulling back the wafer from the resist coating processing unit (COT).
Ends the delivery (STEP 1).

Next, the spin chuck 51 is lowered until the wafer W reaches a fixed position in the cup CP, and first the drive motor 52 moves the spin chuck 51 to 1000 rp.
The wafer W is rotated at a rotation speed of about m to make the temperature of the wafer W uniform (STEP 2).

Then, the rotation of the spin chuck 51 is stopped, the jet head 60 is moved by the drive mechanism 70 in the Y direction to a position directly above the wafer W, and the solvent supply nozzle 80 is moved.
When the discharge port reaches the center of the spin chuck 51 (the center of the wafer W), a solvent such as a thinner that dissolves the resist is supplied to substantially the center of the surface of the stationary wafer W, preferably at a predetermined speed of 1000 rpm or less. A pre-wet process is performed in which the wafer W is rotated at a rotation speed of 5 to spread the solvent supplied to the surface of the wafer W over the entire surface of the wafer W (ST.
EP3). As a result, the wettability of the resist solution is improved, and the amount of resist discharged onto the wafer W can be reduced.

Subsequently, the drive mechanism 70 moves the nozzle head 60 in the Y direction until the ejection port of the resist solution supply nozzle 90 reaches the center of the spin chuck 51 (center of the wafer W), and the rotation speed of the wafer W is changed. After rising to a predetermined value, the resist solution is supplied from the discharge port of the resist solution supply nozzle 90 to approximately the center of the surface of the rotating wafer W, and the resist solution is diffused outward by centrifugal force to apply the resist to the surface of the wafer W. Processing is performed (STEP 4). In this resist coating process, first, in order to spread the resist liquid, the resist liquid is discharged and rotated at a relatively high speed. The rotation speed at this time is 2000 to 60 for a 200 mm wafer.
1000-4 for 00 rpm, 300 mm wafer
It is preferably 000 rpm. After that, the supply of the resist solution is stopped and the rotation speed of the wafer W is reduced.
As a result, the film thickness adjusting function is exerted, and uniformization of the film thickness within the surface of the wafer W is promoted. This effect is exerted when the rotational speed of the wafer W is decelerated, a force toward the center acts on the resist solution on the semiconductor wafer W due to the acceleration at the time of deceleration, and moreover, the substrate to be processed is This is because the rotation is slow and the resist solution dries slowly, resulting in the function of adjusting the film thickness. That is, due to the inward force acting by this deceleration, the amount of resist scattered to the outside of the wafer W is suppressed, and the resist is held on the outer peripheral portion as well as the central portion, so that the film thickness of the resist film becomes more uniform. It will be. The rotation speed at this time is 50-
1000 rpm is preferred. Particularly, if it is 500 rpm or less, the resist is hardly dried, and the degree of freedom in adjusting the film thickness is high. The holding time at this time is set to an appropriate time up to 3 seconds, for example. It should be noted that deceleration of the rotation at this time is not indispensable and is performed as necessary.

After that, the rotation speed of the wafer W is increased to shake off the remaining resist solution (STEP 5). The rotation speed at this time is 1500 for a 200 mm wafer.
~ 4000 rpm, 100 for 300 mm wafers
It is preferably 0 to 3000 rpm.

After that, the rotation of the wafer W is continued to dry the resist film (STEP 6). The rotation speed at this time is 1000 to 2000 r for a 200 mm wafer.
pm, 500-1500r for 300 mm wafers
It is preferably pm. After performing this process for a predetermined time, the resist coating process is completed.

Next, the control during the resist coating process will be described in detail. When the resist solution is applied, in order to form a resist film with high film thickness accuracy and film thickness uniformity, the rotation of the drive motor 52, the operation of the bellows pump 97, and the air operation valve which is an opening / closing valve are conventionally performed by software. The operation of 94 is strictly controlled. FIG. 8 shows ideal timings of these operations when the resist solution is applied by the conventional control. First, the controller 100 simultaneously sends a drive start signal to the drive motor 52, a discharge operation start signal to the bellows pump 97, and an open signal to the air operation valve 94. As a result, the rotation of the spin chuck 51 is started, and the rotation speed increases. The bellows pump 97 is the controller 10
The resist solution is discharged almost at the same time as the command from 0, the air operation valve 94 is opened with a slight delay, and the resist solution is discharged onto the wafer W. The ejection timing at this time is adjusted so that the wafer W rotating together with the spin chuck 51 is still rotating at a low speed. Then, as shown in FIG. 8, after the discharge time t ₀ on the signal has elapsed, the controller 100 simultaneously sends a discharge operation end signal to the bellows pump 97 and a close signal to the air operation valve 94, and these signals are sent. After a slight delay from, the air operation valve 94 is actually closed, and a drive stop signal is sent to the drive motor 52 so that the rotation of the wafer W is decelerated at that time. In this case, the actual ejection time t ₁ almost coincides with the ejection time t ₀ on the signal, and no problem occurs.

However, not all the air operation valves 94 operate ideally, and from the time a signal is received to the time it starts operating due to individual differences in manufacturing, changes over time, differences in installation conditions, etc. There will be a difference in time. Then, in some cases, as shown in FIG. 9, a delay time Δt from an ideal time until an open signal is sent to the air operation valve 94 and the valve is actually opened.
Becomes larger and the valve 94 is actually opened to discharge the resist solution, the rotation speed of the wafer W may reach the maximum speed or its vicinity. When the resist solution is discharged while the rotation speed of the wafer W is high,
The film thickness of the resist film largely deviates from the set value. Further, in this case, the amount of the resist solution discharged is delayed,
Although the actual discharge time t ₁ ′ of the resist solution is shorter than t ₁ ,
As the delay time Δt becomes large and the discharge time becomes short, the film thickness around the wafer W becomes thin, and the uniformity of the resist film thickness deteriorates. FIG. 10 shows the results of performing resist discharge by variously changing the time corresponding to the delay time Δt.
It can be seen that the film thickness uniformity deteriorates as the time corresponding to Δt increases. Such deterioration of the film thickness uniformity is caused by
This is particularly noticeable when pre-wetting the solvent to reduce the consumption of the resist solution.

Therefore, in this embodiment, as described above,
An open / close detector 94a for the air operation valve 94 is provided to detect a signal indicating that the air operation valve 94 is opened, and control the resist coating process based on the signal.

Specifically, as shown in FIG. 11, the controller 10 is based on a signal which is detected by the opening / closing detector 94a and indicates that the air operation valve 94 is opened.
0 sends a drive start signal to the drive motor 52 to rotate the wafer W. And this air operation valve 9
The controller 100 controls the discharge end time of the resist solution on the basis of the signal indicating that No. 4 is opened. That is, the controller 100 calculates the delay time Δt from the signal indicating that the air operation valve 94 has been opened, and the resist liquid discharge time is extended by the time corresponding to the delay time Δt to obtain the actual resist liquid. Discharge time t ₁ ″
To be approximately the same as t ₁ .

The control flow in this case will be described with reference to the flowchart of FIG. First, the controller 100 simultaneously sends a discharge operation start signal to the bellows pump 97 and an open signal to the air operation valve 94 (STE).
P11). Then, the opening / closing detector 94a detects that the air operation valve 94 is opened (STEP
12), the controller 100 that receives the detection signal
Outputs a drive start signal from the drive motor 52 to the drive motor 52 (STE
P13). As a result, the discharge of the resist solution is started while the wafer W is rotating at a low speed. When discharging the resist liquid, the air operation valve 9 is used during the discharging time.
7 is controlled to strictly control the resist solution discharge rate (STEP 14). At this time, when the time when the opening of the air operation valve 94 is detected is delayed from the time when the air operation valve 94 should actually be opened, the discharge rate is also controlled based on the delay time to achieve high accuracy. Control can be performed. However, since controlling the discharge rate based on the data of the wafer currently being processed requires the controller 100 to have an extremely high capacity, it is not the delay time Δt _{n of the} wafer currently being processed but one wafer. Delay time Δt _n-1 detected on the previous wafer
The discharge rate of the bellows pump 97 is controlled based on the above. Since the characteristics of the air operation valve 94 hardly change in a short period of time, high accuracy can be maintained even with such control. Of course, if the performance of the controller 100 is sufficiently high, Δt _n can be used. next,
The controller 100 calculates the delay time Δt _n from the detection result in STEP 12, sends a closing signal to the air operation valve 94 and a drive stop signal to the drive motor 52 based on the values, and based on the delay time Δt _n−1. Send a discharge operation stop signal to the bellows pump 97 (STEP
15). When controlling the discharge rate of the bellows pump 97 based on Delta] t _n sends the discharge operation stop signal to the bellows pump 97 based on Delta] t _n. As described above, the operation of controlling the discharge of the resist solution and spreading the resist solution over the entire surface of the wafer W is completed.

Thereafter, as described above, the wafer W is rotated at a low speed as necessary, and the resist solution coating process (ST
After EP4) is completed, the resist solution is shaken off (STEP
5), a resist film drying process (STEP6) is performed.

As described above, when the resist solution is discharged, the opening / closing detector 94a detects a signal indicating that the air operation valve 94 is opened, and the resist solution coating process is controlled based on the signal. It is possible to control various conditions after grasping the time when the resist liquid is actually discharged, and even if the air operation valve 94 is actually opened late, the resist film has high film thickness accuracy and film thickness uniformity. Can be formed with.

Specifically, the opening / closing detector 94a detects a signal indicating that the air operation valve 94 is opened, and controls the wafer W to rotate based on the signal, so that the resist solution is discharged. At this point, the rotation speed of the wafer W is prevented from being too high so that the resist film does not reach a predetermined thickness. Further, the signal indicating that the air operation valve 94 is opened is detected, the delay time Δt is calculated from the signal, and the discharge of the resist liquid is ended. Therefore, the actual discharge time of the resist liquid is kept substantially constant. Therefore, the film thickness uniformity of the resist film can be further enhanced.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above-described embodiment, the case where the signal of opening the air operation valve of the wafer actually being processed is detected and the drive motor for rotating the spin chuck is controlled based on the signal has been described. It is also possible to control based on the detected data at that time. Thereby, for example, the rotation speed of the wafer when the resist liquid is discharged can be controlled with high accuracy. Further, in the above-described embodiment, the drive motor is stopped after a preset time from the detection of the signal indicating that the air operation valve is opened, but the opening / closing detector closes the air operation valve. It is also possible to detect a signal indicating that, and stop the drive motor based on the signal to control the rotation of the wafer. Thereby, the film thickness can be controlled with higher accuracy. Further, as the open / close detector of the air operation valve, one having a light emitting element and a light receiving element is used, but the present invention is not limited to this, and a pressure sensor for detecting the pressure in the container 111 of the air operation valve is provided, and the change of the pressure is It is also possible to detect opening and closing of the valve by. Furthermore, although the case where the resist solution is used as the coating solution is shown, the application solution is not limited to the resist solution, and the coating solution for the film formed by performing the spin coating process such as the antireflection film and the interlayer insulating film may be used. It may be a coating liquid. Furthermore, in the above embodiment, the case where the semiconductor wafer is used as the substrate to be processed has been described.
The substrate is not limited to a semiconductor wafer, and may be another substrate to be processed such as an LCD substrate or a mask reticle substrate.

[0061]

As described above, according to the present invention,
When discharging the coating liquid, a signal indicating that the valve provided in the pipe for supplying the coating liquid to the coating liquid discharge nozzle has been opened is detected, and the coating process is controlled based on the signal, so in practice Various conditions can be controlled after grasping the time when the coating liquid is discharged, and a coating film such as a resist film can be formed with high film thickness accuracy and film thickness uniformity even if the valve opening is delayed. .

Specifically, a signal indicating that the valve has been opened is detected, and the substrate to be processed is controlled to rotate based on the signal so that the substrate to be processed is discharged at the time when the coating liquid is discharged. It is possible to prevent inconveniences such as an excessively high rotation speed of the film, which causes a film thickness variation.

Furthermore, by controlling the discharge end time of the coating liquid based on the signal indicating that the valve has been opened, the actual discharge time of the coating liquid can be made constant and the coating film The film thickness accuracy and film thickness uniformity can be further enhanced.

[Brief description of drawings]

FIG. 1 is a plan view showing the overall configuration of a semiconductor wafer resist coating / developing system in which a resist coating processing unit for carrying out the present invention is mounted.

FIG. 2 is a front view of the resist coating and developing treatment system shown in FIG.

3 is a rear view of the resist coating and developing treatment system shown in FIG.

4 is a cross-sectional view showing an overall configuration of a resist coating processing unit mounted in the coating and developing processing system shown in FIG.

5 is a plan view of the resist coating processing unit shown in FIG.

FIG. 6 is a cross-sectional view showing an air operation valve and an opening / closing detector provided in the resist coating processing unit.

FIG. 7 is a process drawing showing a processing step in a resist coating processing unit.

FIG. 8 is a graph showing ideal timings of operations of a drive motor, a bellows pump, and an air operation valve when a resist solution is applied by conventional control.

FIG. 9 is a graph showing operation timings of a drive motor, a bellows pump, and an air operation valve when a discharge delay occurs when a resist solution is applied by conventional control.

FIG. 10 is a graph showing changes in film thickness uniformity with changes in resist solution discharge time.

FIG. 11 is a graph showing operation timings of the drive motor, the bellows pump, and the air operation valve when the resist solution is applied under the control of the embodiment of the present invention.

FIG. 12 is a flowchart showing a control flow when a resist solution is applied under the control of the embodiment of the present invention.

FIG. 13 is a schematic configuration diagram of a conventional resist coating apparatus.

[Explanation of symbols]

51 ... Spin chuck (substrate holding member) 52 ... Drive motor 60 ... Spout 90 ... Resist liquid supply nozzle 91: Resist solution supply pipe 94 ... Air operation valve 94a ... Open / close detector (open detection means) 97 ... Bellows pump 100 ... Controller W: Semiconductor wafer (substrate to be processed)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) H01L 21/027 H01L 21/30 564C (72) Inventor Yoshiki Fukuda 5-3-6 Akasaka, Minato-ku, Tokyo TBS Broadcast Center Tokyo Electron Ltd. (72) Inventor Akihiro Fujimoto 5-3-6 Akasaka, Minato-ku, Tokyo TBS Broadcast Center Tokyo Electron Ltd. F-term (reference) 2H025 AA18 AB16 EA05 4D075 AC65 AC94 CA47 DA06 DB14 DC22 EA05 EA45 4F042 AA07 BA05 BA06 CB02 CB08 CB11 CB19 EB05 EB09 EB13 EB18 EB24 EB29 5F046 JA02 JA03 JA09 JA13

Claims (17)

[Claims] 1. A coating treatment method for forming a coating film by discharging a coating liquid substantially at the center of a substrate to be processed, rotating the substrate to be processed, and spreading the coating liquid radially outward of the substrate to be processed. When discharging the coating liquid, a signal indicating that a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle is opened is detected, and the coating process is controlled based on the signal. And coating treatment method. 2. A coating treatment method for forming a coating film by discharging a coating liquid to a substantially central portion of a substrate to be processed and rotating the substrate to be processed to spread the coating liquid radially outward of the substrate to be processed. A step of sending a drive signal to a pump for discharging the coating liquid from the coating liquid discharge nozzle and sending an open signal to a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle; and the valve being opened. And a step of rotating the substrate to be processed based on the signal indicating that the valve has been opened. 3. A coating treatment method for forming a coating film by discharging a coating liquid substantially at the center of a substrate to be processed, rotating the substrate to be processed, and spreading the coating liquid radially outward of the substrate to be processed. A step of sending a drive signal to a pump for discharging the coating liquid from the coating liquid discharge nozzle and sending an open signal to a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle; and the valve being opened. The step of detecting the signal indicating that the valve is opened, the step of starting the rotation of the substrate to be processed based on the signal indicating that the valve is opened, and the coating based on the signal indicating that the valve is opened. And a step of controlling the liquid discharge end time. 4. The step of controlling the discharge end time of the coating liquid is delayed from the time when an open signal is sent to the valve and the valve is actually opened to the time when the signal indicating the opening is detected. The coating processing method according to claim 3, wherein the time when the driving of the pump is stopped and the time when the valve is closed are controlled based on time. 5. The driving stop time of the pump is controlled based on the coating liquid discharge rate and the delay time grasped when performing a coating process on a conventional substrate to be processed. 4. The coating treatment method according to 4. 6. The rotation of the substrate to be processed is reduced after a preset time from the detection of the signal indicating that the valve has been opened, according to any one of claims 3 to 5. The coating treatment method according to item 1. 7. The method according to claim 3, wherein a signal indicating that the valve is closed is detected, and the rotation of the substrate to be processed is reduced based on the signal. The coating treatment method according to the item. 8. The signal indicating that the valve provided in the coating liquid discharge nozzle has been opened is detected when performing a coating process on a conventional substrate to be processed. 8. The coating treatment method according to claim 7. 9. A coating processing apparatus for forming a coating film by discharging a coating liquid substantially at the center of a substrate to be processed, rotating the substrate to be processed, and spreading the coating liquid radially outward of the substrate to be processed. A substrate holding member that holds the substrate to be processed substantially horizontally, a motor that rotates the substrate holding member, and a coating liquid discharge for supplying the coating liquid to substantially the center of the substrate to be processed held by the substrate holding member A nozzle, a pump for discharging the coating liquid from the coating liquid discharge nozzle, a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle, and a signal indicating that the valve is opened is detected. The coating processing apparatus is characterized by comprising: an open detection unit for controlling the motor, and a control unit for receiving a detection signal of the open detection unit and starting driving of the motor based on the detection signal. 10. A coating processing apparatus for forming a coating film by ejecting a coating liquid substantially at the center of a substrate to be processed, rotating the substrate to be processed, and spreading the coating liquid outward in the radial direction of the substrate to be processed. A substrate holding member that holds the substrate to be processed substantially horizontally, a motor that rotates the substrate holding member, and a coating liquid discharge for supplying the coating liquid to substantially the center of the substrate to be processed held by the substrate holding member A nozzle, a pump for discharging the coating liquid from the coating liquid discharge nozzle, a valve provided in a pipe for supplying the coating liquid to the coating liquid discharge nozzle, and a signal indicating that the valve is opened is detected. Open detection means, and the detection signal of the open detection means is input, based on the detection signal, to start the drive of the motor, and the end point of the discharge of the coating liquid and the stop point of the drive of the motor. Coating treatment apparatus characterized by comprising a Gosuru control means. 11. The control means drives the pump based on a delay time from the time when an open signal is sent to the valve and the valve is actually opened to the time when the signal indicating the opening is detected. 11. Controlling the time when the valve is stopped and the time when the valve is closed.
The coating treatment apparatus according to. 12. The control means, based on the delay time grasped when performing a coating process on a conventional substrate to be processed,
The coating processing apparatus according to claim 11, wherein the driving stop time of the pump is controlled together with the coating liquid discharge rate. 13. The control means stops driving of the motor after a preset time has elapsed after receiving a signal indicating that the valve has been opened detected by the opening detection means. The coating treatment apparatus according to any one of claims 10 to 12. 14. The control means further includes a closing detection means for detecting a signal indicating that the valve is closed, and the control means receives a signal indicating that the valve is closed detected by the closing detection means. Based on the detected signal
The coating processing apparatus according to claim 10, wherein driving of the motor is stopped. 15. The opening detection means detects opening of the valve by detecting movement of a valve body of the valve.
The coating treatment apparatus according to any one of 1. 16. The opening detection means detects that the valve is opened by detecting the pressure inside the valve.
The coating treatment apparatus according to any one of 1. 17. The control means performs control based on a signal indicating that the valve has been opened, which is detected when performing a coating process on a conventional substrate to be processed. 17. The coating processing apparatus according to claim 16.