JP2000068182A - Coating method and coating device - Google Patents

Abstract

(57) [Problem] To provide a coating method and a coating apparatus capable of reducing the amount of a solvent contained in a resist. A resist solution is supplied near the center of the upper surface of a wafer W held on a spin chuck 51. First, the wafer W is rotated at a low speed to diffuse the resist solution to a certain extent on the upper surface of the wafer W. Thereafter, the number of revolutions of the wafer W is increased to a high speed at a stretch with a rapid acceleration, and a strong centrifugal force is generated. With this strong centrifugal force, excess resist liquid is shaken off and removed, and the resist liquid remaining on the upper surface of the wafer W is further diffused to form a thin coating film. Since the resist solution is diffused and thinned by a strong centrifugal force, the amount of solvent contained in the resist can be significantly reduced. Also, the throughput is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating method and a coating apparatus for coating a resist material or the like on a substrate to be processed such as a silicon wafer in a semiconductor manufacturing process by photolithography.

[0002]

2. Description of the Related Art Conventionally, as a method of applying a coating material such as a resist material to a substrate such as a silicon wafer, a method called a spin coating method is generally used.

In the spin coating method, a substrate such as a silicon wafer is sucked and held on a disk-shaped holding member called a spin chuck, and a solution-like resist material is discharged almost to the center of the substrate. This is a method of rotating a spin chuck at high speed. By rotating the spin chuck at high speed, a centrifugal force acts on the resist material located at the center, and the resist material diffuses radially outward from the center on the substrate surface by the centrifugal force, and covers the entire substrate surface.
When the high-speed rotation is further continued, the excess resist material is shaken off by centrifugal force, and a thin coating film having a uniform film thickness is formed on the substrate. The resist material used in the spin coating method is a solution in which a photosensitive resin or the like is dissolved in a solvent. Since it is necessary to form a thin resist film in order to form an integrated circuit with a high degree of integration, a dilute resist solution using a large amount of a solvent for a resin is often used.

[0004]

However, in today's society where environmental protection measures are demanded by society, there is a demand from semiconductor manufacturers to reduce the amount of organic solvents used in the manufacture of semiconductors.

In some cases, prior to discharging the resist solution onto the substrate, the surface of the substrate is wetted with a solvent in advance, and a pre-wet treatment is performed to improve the wettability between the resist solution and the substrate. When performing this pre-wet treatment, an extra step of supplying a solvent is required in addition to the step of discharging the resist solution, and the time from the input of the raw materials to the completion of the product becomes longer, the throughput is reduced, and the production cost is reduced. Has led to a rise.

Further, there is a problem that the amount of solvent used increases due to the application of the pre-wet treatment, and the amount of waste liquid increases accordingly.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a coating method and a coating apparatus capable of reducing the amount of a solvent contained in a resist.

Another object of the present invention is to provide a coating method and a coating apparatus capable of improving throughput by reducing the amount of solvent used.

Another object of the present invention is to provide a coating method and a coating apparatus capable of reducing the total amount of solvent used during semiconductor production.

[0010]

According to a first aspect of the present invention, there is provided a coating method comprising: supplying a coating material onto a substrate to be processed; and rotating the substrate at a first speed. And accelerating the substrate to be processed to a second speed at a predetermined acceleration.

The coating method according to a second aspect is the coating method according to the first aspect, wherein the step of rotating the substrate to be processed at a third speed after accelerating at a predetermined acceleration to the second speed. It is further characterized by comprising:

According to a third aspect of the present invention, there is provided a coating method comprising: supplying a coating material onto a substrate to be processed; rotating the substrate to be processed at a first speed; Accelerating at a predetermined acceleration, detecting the thickness of the coating agent layer on the substrate, and determining a third speed of rotating the substrate based on the detected thickness. And a step of rotating the substrate to be processed at the determined third speed.

According to a fourth aspect of the present invention, there is provided a coating method comprising: a step of supplying a coating agent onto a substrate to be processed; a step of rotating the substrate to be processed at a first speed; A step of accelerating at a predetermined first acceleration, a step of detecting a film thickness of the coating agent layer on the substrate to be processed, and a third speed and a speed of rotating the substrate to be processed based on the detected film thickness. A step of determining a second acceleration up to the third speed; and a step of rotating the substrate to be processed at the determined third speed and the second acceleration.

[0014] The coating method according to the fifth aspect is the first to fourth aspects.
The coating method according to any one of the above, wherein the first speed is 100 to 500 r. p. m. It is characterized by being.

The coating method according to the sixth aspect is the first to fifth aspects.
The coating method according to any one of the above, wherein the second speed is 3000 to 6000 r. p. m. It is characterized by being.

[0016] The coating method according to the seventh aspect is the first to sixth aspects.
The method according to any one of claims 1 to 3, wherein the first acceleration is 30,000 to 60000 r. p. m. / Sec.

The coating method according to claim 8 is the coating method according to claim 4, wherein the third speed is 1000 to 4
000r. p. m. It is characterized by being.

According to a ninth aspect of the present invention, there is provided a coating apparatus, comprising: holding means for holding a substrate to be processed; rotation driving means for rotating the holding means;
Means for detecting the thickness of the coating agent layer on the substrate to be processed,
Means for controlling a rotation speed and a rotation acceleration of the rotation drive means based on the detected film thickness of the coating material layer.

A coating apparatus according to a tenth aspect of the present invention is a spin chuck for holding a substrate to be processed, a rotation drive mechanism for rotating the holding means, an application agent supply mechanism for supplying an application agent to the substrate to be processed, A sensor for detecting the thickness of the coating material layer on the substrate to be processed; and a control unit for controlling a rotation speed and a rotation acceleration of the rotation drive mechanism based on the detected film thickness of the coating material layer. .

The coating apparatus according to claim 11, wherein a spin chuck for holding the substrate to be processed, a rotation drive mechanism for rotating the holding means, a coating agent supply mechanism for supplying a coating agent to the substrate to be processed, A sensor for detecting the weight of the coating material layer on the substrate to be processed, and a control unit for controlling a rotation speed and a rotation acceleration of the rotation drive mechanism based on the detected weight of the coating material layer are provided.

According to a twelfth aspect of the present invention, in the coating apparatus, a spin chuck for holding the substrate to be processed, a rotation drive mechanism for rotating the holding means, a coating agent supply mechanism for supplying a coating agent to the substrate to be processed, A sensor that detects a change in the refractive index of the coating material layer on the substrate to be processed, and a control unit that controls the rotation speed and the rotational acceleration of the rotation drive mechanism based on the detected change in the refractive index of the coating material layer. Have.

In the coating method according to the first and second aspects, a large centrifugal force acts when the substrate to be processed is accelerated with a large acceleration after being rotated at the first speed and before being rotated at the second speed. Since the coating agent supplied on the substrate to be processed is thinned by using the method, the amount of the solvent in the coating agent can be greatly reduced. Further, since the pre-wet treatment can be omitted, the throughput can be improved, and a solvent for the pre-wet treatment is not required, so that there is no problem of waste liquid treatment.

According to a third aspect of the present invention, the film thickness of the coating agent layer on the substrate to be processed is detected after the coating agent on the substrate to be processed is thinned by acceleration at the predetermined acceleration. The subsequent third speed is determined based on the determined film thickness, and the substrate to be processed is rotated at the determined third speed, so that the final coating film thickness can be more accurately determined. Can be formed.

In the coating method according to a fourth aspect, in addition to the third speed according to the third aspect, the second acceleration is also determined based on the detected film thickness for the second acceleration, and the determined second acceleration is determined. Since the rotational speed of the substrate to be processed is accelerated by applying a stronger centrifugal force, the final coating film thickness can be formed more accurately and quickly.

According to a fifth aspect of the present invention, in the coating method according to any one of the first to fourth aspects, the first speed is 100 to 500 rpm. p. m. Is adopted, the coating agent supplied onto the substrate to be processed can be reliably diffused outward in the radial direction of the substrate to be processed.

According to a sixth aspect of the present invention, in the coating method according to any one of the first to fifth aspects, the second speed is 3,000 to 6,000 rpm. p. m. Is employed, it is possible to reliably reduce the thickness of the coating material supplied onto the substrate to be processed.

According to a seventh aspect of the present invention, in the coating method according to any one of the first to sixth aspects, the first acceleration is 30,000 to 60000 r. p. m. Since / sec is adopted, the coating agent supplied on the substrate to be processed can be reliably thinned.

In the coating method according to an eighth aspect, in the coating method according to the fourth aspect, the third speed is set at 1000
~ 4000 r. p. m. Is employed, it is possible to reliably reduce the thickness of the coating material supplied onto the substrate to be processed.

According to a ninth aspect of the present invention, since the rotation speed and the rotation acceleration of the rotation driving means are controlled based on the detected film thickness of the coating agent layer, a final result is obtained. The thickness of the coating film can be accurately formed.

According to a tenth aspect of the present invention, the rotational speed and the rotational acceleration of the rotary drive mechanism are controlled based on the thickness of the coating agent layer detected by the sensor. The thickness of the obtained coating film can be accurately formed.

In the coating apparatus of the present invention, the rotation speed and the rotation acceleration of the rotation drive mechanism are controlled based on the weight of the coating agent layer detected by the sensor. The thickness of the coating film to be formed can be formed accurately.

In the coating apparatus according to the twelfth aspect, the rotation speed and the rotation acceleration of the rotary drive mechanism are controlled based on the change in the refractive index of the coating agent layer detected by the sensor. The film thickness of the obtained coating film can be accurately formed.

[0033]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a semiconductor wafer (hereinafter, referred to as “COT”) provided with a resist coating unit (COT) according to an embodiment of the present invention.
FIG. 1 is a plan view showing the entire coating and developing processing system 1 of “wafer”).

In the coating and developing processing system 1, a plurality of wafers W as objects to be processed are loaded into and unloaded from the system in units of, for example, 25 wafers, eg, 25 wafers. A cassette station 10 for loading and unloading, a processing station 11 in which various single-wafer processing units for performing predetermined processing on the wafers W one by one in a coating and developing process are arranged at predetermined positions in multiple stages, and An interface unit 12 for transferring a wafer W to and from an exposure apparatus (not shown) provided adjacent to the processing station 11 is integrally connected. In this cassette station 10,
At the position of the positioning projection 20a on the cassette mounting table 20,
A plurality of, for example, up to four wafer cassettes CR are placed in a line in the X direction (vertical direction in FIG. 1) with their respective wafer entrances facing the processing station 11 side. The wafer carrier 21 that can move in the wafer arrangement direction (Z direction; vertical direction) of the wafers W stored in the wafer CR selectively accesses each wafer cassette CR.

The wafer transfer body 21 is rotatable in the θ direction, and the wafer transfer body 21
Access to the processing unit group G ₃ of the multi-stage unit section disposed in the alignment unit (ALIM) and an extension unit (EXT).

The processing station 11 is provided with a vertical transfer type main arm 22 having a wafer transfer device.
All the processing units are arranged in multiple stages around one or more sets.

FIG. 2 is a front view of the coating and developing system 1.

In the first processing unit group G ₁ , the cup C
Two spinner type processing units, for example, a resist coating unit (COT) and a developing unit (DEV), which perform a predetermined process by placing the wafer W on the spin chuck in the P, are stacked in two stages from the bottom. In the second processing unit group G _2, two spinner-type processing units, for example, the resist coating unit (COT) and a developing unit (D
EV) are stacked in two stages in order from the bottom. These resist coating units (COT) are preferably arranged in the lower stage as described above because drainage of the resist solution is troublesome both mechanically and in terms of maintenance. However, it is of course possible to appropriately arrange the upper stage as needed.

FIG. 3 is a rear view of the coating and developing system 1.

In the main arm 22, a wafer transfer device 46 is mounted inside the cylindrical support 49 so as to be able to move up and down in the vertical direction (Z direction). The cylindrical support 49 is connected to a rotation shaft of a motor (not shown), and is rotated integrally with the wafer transfer device 46 about the rotation shaft by the rotation driving force of the motor, whereby the wafer transfer is performed. The device 46 is rotatable in the θ direction. Note that the cylindrical support 49 may be configured to be connected to another rotating shaft (not shown) rotated by the motor.

The wafer transfer device 46 is provided with a plurality of holding members 48 movable in the front-rear direction of the transfer base 47, and these holding members 48 transfer the wafer W between the processing units. Is possible.

Further, as shown in FIG. 1, in the coating and developing processing system 1, five processing unit groups G ₁ , G ₂ , G
₃ , G ₄ , G ₅ can be arranged, and the multi-stage units of the first and second processing unit groups G ₁ , G ₂ are arranged on the system front (front side in FIG. 1) side, and the third processing unit multistage unit group G ₃ are cassette station 10
, And the multi-stage unit of the _fourth processing unit group G ₄ is disposed adjacent to the interface unit 12,
Multistage unit of the fifth processing unit group G ₅ is capable of being disposed on the rear side.

As shown in FIG. 3, in the third processing unit group G ₃ , an oven-type processing unit for performing a predetermined process by placing the wafer W on a holding table (not shown), for example, a cooling system for performing a cooling process Unit (COL), adhesion unit (AD) for performing so-called hydrophobic treatment for improving the fixability of resist, alignment unit (ALIM) for positioning, extension unit (EXT), heat treatment before exposure processing Prebaking unit (PREBAKE) for performing heat treatment and postbaking unit (POBAKE) for performing heat treatment after exposure processing
Are, for example, stacked in eight stages from the bottom. Even the fourth processing unit group G _4, oven-type processing units, for example, a cooling unit (COL), an extension and cooling unit (EXTCOL), extension unit (EXT), a cooling unit Bok (CO
L), a pre-baking unit (PREBAKE) and a post-baking unit (POBAKE) are stacked in order from the bottom, for example, in eight stages.

As described above, the cooling unit (COL) and the extension cooling unit (EXTCOL) having a low processing temperature are arranged in the lower stage, and the baking unit (PREBAKE), the post-baking unit (POBAKE) and the adhesion having a high processing temperature are arranged. By arranging the units (AD) in the upper stage, thermal mutual interference between the units can be reduced. Of course, a random multi-stage arrangement may be used.

As shown in FIG.
In the depth direction (X direction), the processing station 11
But has a smaller size in the width direction (Y direction). A portable pickup cassette CR and a stationary buffer cassette BR are arranged in two stages at the front of the interface unit 12, while a peripheral exposure device 23 is arranged at the rear, and a central exposure unit is further arranged at the center. Is provided with a wafer carrier 24. This wafer carrier 24
Moves in the X and Z directions to access both cassettes CR and BR and the peripheral exposure device 23.

The wafer transfer body 24 is also rotatable in the θ direction, and includes an extension unit (EXT) provided in the multi-stage unit of the fourth processing unit group G ₄ on the processing station 11 side, and an adjacent exposure unit. The wafer delivery table (not shown) on the apparatus side can also be accessed.

In the coating and developing system 1, the multi-stage unit of the _fifth processing unit group G5 shown by the broken line in FIG. 1 can be arranged on the back side of the main arm 22 as described above. multistage unit of the processing unit group G ₅ is
It is movable in the Y direction along the guide rail 25. Therefore, even if this is provided fifth as illustrated multistage unit of the processing unit group G ₅ of, by moving along the guide rail 25, the space portion can be secured, behind the main arm 22 Maintenance work can be performed easily.

Next, the resist coating unit (COT) according to the present embodiment will be described. FIG. 4 is a schematic sectional view of the resist coating unit (COT) according to the present embodiment.

An annular cup C # is provided at the center of the resist coating unit (COT), and a spin chuck 51 is provided inside the cup C #. The spin chuck 51 is rotationally driven by a drive motor 52 in a state where the wafer W is fixedly held by vacuum suction.

The drive motor 52 is disposed in an opening 50a provided in the unit bottom plate 50 so as to be able to move up and down, and a cap-shaped flange member 53 made of, for example, aluminum.
Lifting drive means 5 comprising, for example, an air cylinder
4 and the lifting guide means 55.

A resist nozzle 60 for discharging a resist liquid as a coating liquid onto the surface of the wafer W is detachably attached to a tip of a resist nozzle scan arm 61 via a nozzle holder 62. The resist nozzle scan arm 61 is attached to the upper end of a vertical support member 64 that can move horizontally on a guide rail 63 laid in one direction (Y direction) on the unit bottom plate 50, and is not shown in the Y direction. Vertical support member 6 by drive mechanism
4 and moves in the Y direction.

FIG. 5 is a schematic plan view of a resist coating unit (COT) according to the present embodiment.

The resist nozzle scan arm 61 can also be moved in the Χ direction perpendicular to the Y direction in order to selectively mount the resist nozzle 60 in the resist nozzle standby section 65, and is moved in the Χ direction by a Χ direction driving mechanism (not shown). Can also move.

Further, the discharge opening of the resist nozzle 60 is inserted into the opening 65a of the solvent atmosphere chamber in the resist nozzle standby section 65, and is exposed to the solvent atmosphere inside, so that the resist liquid at the tip of the resist nozzle 60 solidifies or deteriorates. Not to be. Further, a plurality of resist nozzles 60,
Are provided, and the resist nozzles 60 can be used properly according to the type and viscosity of the resist solution.

Further, on the guide rail 63, a vertical support member 6 for supporting the resist nozzle scan arm 61 is provided.
In addition to the vertical support member 4, a vertical support member 71 that supports the rinse nozzle scan arm 70 and is movable in the Y direction is also provided.

The rinse nozzle scan arm 70 is moved by the Y-direction drive mechanism (not shown) to the rinse nozzle standby position (the position indicated by the solid line) set to the side of the cup CP and the semiconductor wafer W mounted on the spin chuck 51. It is configured to translate or linearly move between a rinsing liquid discharge position (a position indicated by a dotted line) set immediately above the peripheral portion.

As shown in FIG. 4, the resist nozzle 60
Is connected via a resist supply pipe 66 to a resist liquid supply mechanism disposed in the lower chamber of the resist coating unit (COT).

FIG. 6 is a block diagram showing a control system of the resist coating unit (COT) according to the present embodiment. As shown in FIG. 6, this resist coating unit (CO
In T), the drive motor 5 for rotating the spin chuck 51
2, and a resist supply system for supplying a resist to the resist nozzle 60 is connected to the control unit 100, respectively.
The control unit 100 controls the entire system.

Next, the operation of the coating and developing system 1 configured as described above will be described.

The resist coating unit (CO
T), the wafer W is taken out of the wafer cassette CR and transported by the main arm 22 to the resist coating unit (CO).
Access within T). Thereafter, the following resist coating operation is started.

FIG. 7 is a flowchart showing a procedure in the case of performing a coating process in the resist coating unit (COT) according to the present embodiment, and FIG. 8 is a timing chart showing the procedure. 9 to 11 are a perspective view and a sectional view schematically showing a state in each procedure.

First, the main arm 22 delivers the wafer W to a lifter (not shown) of the spin chuck 51 in the coating unit (COT), and sets the wafer W on the spin chuck 51 by lowering the lifter (not shown). Step 1 / time t ₀ ). Next, the resist nozzle scanning arm 61 is moved to move the resist nozzle 60 approximately at the center position of the wafer W before the rotation held by the spin chuck 51, from the resist nozzle 60 for a time t ₁ ~t ₂ wafer A resist solution is discharged onto W (step 2). FIG. 9 shows this state. As shown in FIG. 9, at this time, the wafer W is in a stationary state before rotation, and the discharged resist liquid forms a thick layer near the center of the wafer W.

At time t ₃ , the spin chuck 51 starts rotating (step 3), accelerates at the first acceleration, and at time t ₄ rotates at the first speed at a constant speed (step 4).

The rotation speed at this time, that is, the value of the first speed, is a so-called design item that varies depending on the viscosity and type of the resist solution, the diameter of the wafer W, the temperature and humidity at the time of application, and is uniquely specified. I can't. However, as an example, the first speed is 100 to 500 rpm.
p. m. Is preferable.

Here, the upper limit of the preferable range of the first speed is set at 500 rpm. p. m. The reason for this is that if the first speed exceeds the upper limit, the resist spreads to the outer peripheral portion, which causes a problem that the film cannot be uniformly thinned.

On the other hand, the lower limit of the preferable range of the first speed is set at 100 rpm. p. m. This is because, if the first speed is lower than the lower limit, there is a problem that the resist may not spread on the wafer W depending on the viscosity of the resist.

By the rotation from time t _{3 to} t _5, a centrifugal force acts on the resist liquid discharged onto the wafer W. Due to this centrifugal force, the resist liquid is diffused and spread outward in the radial direction of the wafer W. At the same time, the film thickness decreases, and the resist solution becomes thinner. FIG. 10 shows this state. As shown in FIG. 10, at this point, the outer peripheral portion of the upper surface of the wafer W remains exposed, and the coating film of the resist liquid is still considerably thicker than the final target value.

Next, to accelerate the rotation of the spin chuck 51 toward the time t ₅ ~t ₆ predetermined acceleration, namely in the first acceleration (step 5). A large centrifugal force is generated by this accelerated rotation, and this large centrifugal force acts on the resist liquid on the wafer W. FIG. 11 shows this state.
As shown in FIG. 11, the resist liquid on the wafer W spreads all over the upper surface of the wafer W at a stretch by the action of the large centrifugal force generated by the accelerated rotation, and completely covers the upper surface of the wafer W. Further, by the action of the centrifugal force, the excess resist liquid is dropped off from the upper surface of the wafer W,
Removed from the top surface. As a result, only the amount of the resist solution necessary and sufficient to form a coating film having a desired film thickness is left on the upper surface of the wafer W, and the rest is removed. for that reason,
On the upper surface of the wafer W, a coating film having a target film thickness is uniformly formed.

The value of the first acceleration is a so-called design item that varies depending on the viscosity and type of the resist solution, the diameter of the wafer W, the temperature and humidity at the time of application, and cannot be uniquely specified. However, as an example, 30
000-60000r. p. m. / Sec is preferable.

Here, the upper limit of the first acceleration is 60000
r. p. m. The reason why / sec is set is that if the first acceleration exceeds the upper limit value, the wafer W on the chuck may come off during rotation, or may not operate normally due to the limit of the specifications of the spin motor. This is because it occurs.

On the other hand, the lower limit of the first acceleration is 30000
r. p. m. The reason is that if the first acceleration falls below the lower limit, the resist does not spread to the outer peripheral portion of the wafer W,
This is because there is an adverse effect that the resist is not applied to the outer peripheral portion of the wafer W.

Next, the motor rotates at a speed after acceleration, that is, at a second speed for a predetermined time (t _{6 to} t ₇ ) (step 6).

Here, the rotation at the second speed is for surely diffusing the resist coating film over the entire upper surface of the wafer W.

The value of the second speed is a so-called design item that varies depending on the viscosity and type of the resist solution, the diameter of the wafer W, the temperature and humidity at the time of application, and cannot be uniquely specified. However, as an example, the second speed is 3000 to 6000 r.p. p. m. Is preferable.

Here, the upper limit of the second speed is set to 6000.
r. p. m. The reason is that if the second speed exceeds the upper limit, there is a problem that the wafer W on the chuck comes off the chuck during rotation.

On the other hand, the lower limit of the second speed is 3000
r. p. m. The reason is that if the second speed is lower than the lower limit, there is a problem that the resist does not spread to the outer periphery of the wafer W. After a while, the time t
₇ decelerates ~t ₈ (step 7).

Then, at time t _{8 to} t ₉ , the motor is rotated at a predetermined speed, that is, at a third speed (step 8).

Here, the rotation at the third speed is for the purpose of making the thickness of the resist coating film spread over the entire upper surface of the wafer W uniform and for promoting the drying of the coating film.

The value of the third speed is a so-called design item that varies depending on the viscosity and type of the resist solution, the diameter of the wafer W, the temperature and humidity at the time of application, and cannot be uniquely specified. However, as an example, the third speed is 1000 to 4000 r.p. p. m. Is preferable.

Here, the upper limit of the third speed is 4000
r. p. m. The reason for this is that if the third speed exceeds the above upper limit value, there occurs a problem that stripe-shaped unevenness called wind-off occurs at the outer peripheral portion of the wafer W.

On the other hand, the lower limit of the third speed is 1000
r. p. m. The reason for this is that if the third speed is lower than the lower limit, volatilization does not proceed and the thickness of the resist becomes large at the outer peripheral portion of the wafer W, that is, the outer peripheral portion rises. Because.

[0083] predetermined time, i.e., when the constant rotation at time t ₈ ~t ₉ ends, stops at and time t ₁₀ decelerated at time t ₉ ~t ₁₀ (Step 9).

The wafer W thus completed with the coating process
Is taken out of the coating unit (COT) by the main arm 22 and transported to a unit for performing a subsequent process, for example, a baking unit, and subjected to a heating process.

As described above, in the coating unit (COT) according to the present embodiment, the resist solution is spread on the wafer W at a relatively low speed of the first speed. Become. Therefore, the amount of solvent used can be reduced, and the problem of waste liquid treatment can be reduced.

In addition, since the pre-wet process is not required, the throughput can be improved, and the production efficiency and the production cost can be reduced.

Further, the coating unit (C
In OT), a large centrifugal force is generated by using a strong acceleration of the first acceleration, and the resist liquid is diffused outward in the radial direction of the wafer W by the large centrifugal force so as to make the resist thinner. Even if the liquid does not contain much solvent, a thin and uniform coating film can be formed. Note that the present invention is not limited to this embodiment.
Therefore, although the present embodiment has been described using the silicon wafer W for manufacturing a semiconductor element, it is needless to say that the present invention can be applied to the manufacture of a glass substrate for a liquid crystal display (LCD).

(Examples) Examples of the present invention will be described below.

In this example, the coating process was performed using the coating unit described in the first embodiment.

The processing conditions were as shown below.

Step Time (sec) Rotation speed (rpm) Acceleration (rpm / sec) 2 1 000 10000 3 to 4 1.0 100 10000 5 to 60.5 4500 50,000 7 to 8 20.0 2500 10000 Discharge Volume 0.5 ml Discharge speed 1.0 ml / sec Pump RRC pump Model FT200 (manufactured by Koganei) Air operation valve X-25 (manufactured by CKD) Chemical solution used PFI-38A4 (viscosity 3cP / manufactured by Sumitomo Chemical) When the film thickness of the wafer coated under the above conditions was measured in the following manner, the following measurement results were obtained.
FIG. 12 is a graph of this measurement result. In the film thickness measurement, one sample was extracted from one lot of the product, and measured at 39 places of the sample. Coating device is AC
T-SOG (manufactured by Tokyo Electron Limited) was used. The film thickness was measured using Nanospec M5100-L12 (manufactured by Nanometrics Japan).

Range 39 stdev 13.25 3 sigma 39.75 average 5088.05 max 5102 min 5063 As shown in the above results, the difference between the thinnest part and the thick part is 39 Å, and It is thin and its distribution is very uniform.

(Second Embodiment) Hereinafter, a coating unit according to a second embodiment of the present invention will be described.

The description of the same parts as those in the first embodiment will be omitted.

In the coating processing unit according to the present embodiment,
A sensor S for detecting the film thickness of the coating film formed on the upper surface of the wafer W is provided, and the rotation of the spin chuck 51 is controlled based on the film thickness of the coating film detected by the sensor S.

FIG. 13 is a block diagram showing a control system of the coating processing unit according to this embodiment.

As shown in FIG. 13, in the coating processing unit according to the present embodiment, the sensor S is disposed above the wafer W held by the spin chuck 51, and the film of the coating film on the upper surface of the wafer W is formed. Detect the thickness. The sensor S is connected to a control unit 100 together with a motor 52 for rotating the spin chuck 51 and a resist supply system, and is controlled by the control unit 100.

FIG. 14 is a flowchart showing steps in the case where the coating processing is performed by the coating processing unit according to the present embodiment.

As shown in FIG. 14, in the coating processing unit according to this embodiment, similarly to the first embodiment, after discharging the resist in step 2, the resist is accelerated and rotated at a constant speed (steps 3 and 4). After the resist is diffused to some extent on the wafer W, the resist is accelerated at a higher acceleration (step 5), and is rotated at a constant speed (step 6) to thin the resist on the wafer W.

Then, in the coating processing unit, the film thickness of the thin film on the wafer W is detected by the sensor S described above (Step 7), and whether or not the desired film thickness is formed is determined. Is checked (steps 8 and 9).

More specifically, if the detected film thickness is reduced to an appropriate value, the film thickness is made uniform by rotating at a relatively low speed as described in the first embodiment. Step 10).

On the other hand, if the film thickness is not sufficiently small despite the high-speed rotation in steps 6 and 7,
The rotation speed of the third rotation process is adjusted, specifically, the rotation speed is increased (step 12), and the third rotation process is performed at the increased rotation speed (step 10) to reduce the thickness of the coating film. .

When the number of rotations in the third rotation process is to be increased, an experiment is performed in advance to determine how much to increase the number of rotations, and a database is formed based on the results. decide.

As described above, in the coating processing unit according to the present embodiment, after performing the high-speed rotation processing in steps 5 and 6, the film thickness is detected, and the third rotation processing is performed based on the detected film thickness value. Since the number of rotations is controlled, the film thickness can be managed with higher precision.

In the present embodiment, the film thickness is controlled by lowering the number of rotations of the third rotation processing based on the film thickness detected after the high-speed rotation processing in steps 5 and 6. It is also possible to feedback-control the number of high-speed rotations in steps 5 and 6 based on the detected film thickness.

Further, based on the detected film thickness, the first speed, the second speed, the third speed, the first acceleration, and the second speed
It is also possible to control by combining one or more of the accelerations.

In the present embodiment, the value of the film thickness is directly detected using the sensor S.
The film thickness of the coating film can be obtained by detecting the weight of the wafer W, or the film thickness of the coating film can be obtained from a change in the refractive index of the surface of the wafer W.

[0108]

As described above in detail, according to the first and second aspects of the present invention, it is possible to rotate the substrate to be processed at the first speed and then to rotate at the second speed. Since the coating agent supplied onto the substrate to be processed is made thinner by using a large centrifugal force acting when accelerating at a large acceleration, the amount of solvent in the coating agent can be significantly reduced. Further, since the pre-wet treatment can be omitted, the throughput can be reduced, and a solvent for the pre-wet treatment is not required, so that there is no problem of waste liquid treatment.

According to the third aspect of the present invention, the film thickness of the coating material layer on the substrate to be processed is detected after the coating material on the substrate to be processed is thinned by acceleration at the predetermined acceleration. Determining a subsequent third speed based on the detected film thickness,
Since the substrate to be processed is rotated at the determined third speed, the final coating film thickness can be formed more accurately.

According to the fourth aspect of the invention, in addition to the third speed of the third aspect, the second acceleration is determined based on the detected film thickness for the second acceleration. Since the rotation speed of the substrate to be processed is accelerated by the second acceleration, the final coating film thickness can be formed more accurately and quickly by applying a stronger centrifugal force. .

According to the invention set forth in claim 5, according to claim 1,
In the coating method according to any one of Items 1 to 4, the first speed is 100 to 500 r. p. m. Is adopted, the coating agent supplied onto the substrate to be processed can be reliably diffused outward in the radial direction of the substrate to be processed.

According to the invention of claim 6, according to claim 1,
In the coating method according to any one of Items 1 to 5, the second speed may be 3000 to 6000 r. p. m. Is employed, it is possible to reliably reduce the thickness of the coating material supplied onto the substrate to be processed.

According to the invention of claim 7, according to claim 1,
In the coating method according to any one of Items 1 to 6, the first acceleration may be 30,000 to 60000 r. p. m. / S
Since ec is employed, the coating agent supplied on the substrate to be processed can be reliably thinned.

[0114] In the coating method according to the eighth aspect, in the coating method according to the fourth aspect, the third speed is set at 1000
~ 4000 r. p. m. Is employed, it is possible to reliably reduce the thickness of the coating material supplied onto the substrate to be processed.

According to the ninth aspect of the present invention, since the rotation speed and the rotation acceleration of the rotation driving means are controlled based on the detected film thickness of the coating agent layer, the final configuration is achieved. The film thickness of the obtained coating film can be accurately formed.

According to the tenth aspect of the present invention, the rotation speed and the rotation acceleration of the rotation drive mechanism are controlled based on the thickness of the coating agent layer detected by the sensor. The thickness of the finally obtained coating film can be accurately formed.

According to the eleventh aspect of the present invention, since the rotation speed and the rotation acceleration of the rotation drive mechanism are controlled based on the weight of the coating agent layer detected by the sensor, the final It is possible to accurately form the film thickness of the coating film to be obtained.

According to the twelfth aspect of the invention, the rotation speed and the rotation acceleration of the rotary drive mechanism are controlled based on the change in the refractive index of the coating agent layer detected by the sensor. The film thickness of the finally obtained coating film can be accurately formed.

[Brief description of the drawings]

FIG. 1 is a plan view of a coating and developing system including a resist coating unit according to an embodiment of the present invention.

FIG. 2 is a front view of a coating and developing system including a resist coating unit according to an embodiment of the present invention.

FIG. 3 is a rear view of the coating and developing system including the resist coating unit according to the embodiment of the present invention.

FIG. 4 is a sectional view of a resist coating unit according to the embodiment of the present invention.

FIG. 5 is a plan view of a resist coating unit according to the embodiment of the present invention.

FIG. 6 is a block diagram showing a control system of the resist coating unit according to the embodiment of the present invention.

FIG. 7 is a flowchart showing a coating process of the resist coating unit according to the embodiment of the present invention.

FIG. 8 is a timing chart showing a coating process of the resist coating unit according to the embodiment of the present invention.

FIG. 9 is a diagram schematically showing a coating process of a resist coating unit according to the embodiment of the present invention.

FIG. 10 is a diagram schematically showing a coating process of a resist coating unit according to the embodiment of the present invention.

FIG. 11 is a view schematically showing a coating process of a resist coating unit according to the embodiment of the present invention.

FIG. 12 is a graph showing a film thickness distribution of a coating film formed by performing a coating process of the resist coating unit according to the present embodiment.

FIG. 13 is a block diagram showing a control system of a resist coating unit according to a second embodiment of the present invention.

FIG. 14 is a flowchart showing a coating process of a resist coating unit according to a second embodiment of the present invention.

[Explanation of symbols]

 W wafer 51 spin chuck 52 motor S sensor 100 control unit

Claims (12)

[Claims] A step of supplying a coating agent onto the substrate; a step of rotating the substrate at a first speed; and a step of accelerating the substrate at a predetermined acceleration to a second speed. And a coating method comprising: 2. The coating method according to claim 1, further comprising a step of rotating the substrate to be processed at a third speed after accelerating at a predetermined acceleration to the second speed. Coating method. 3. A step of supplying a coating material on a substrate to be processed, a step of rotating the substrate to be processed at a first speed, and a step of accelerating the substrate to be processed at a predetermined acceleration to a second speed. Detecting a film thickness of the coating agent layer on the substrate to be processed; determining a third speed of rotating the substrate to be processed based on the detected film thickness; Rotating the substrate to be processed at a speed of 3. 4. A step of supplying a coating agent on a substrate to be processed, a step of rotating the substrate to be processed at a first speed, and accelerating the substrate to be processed at a predetermined first acceleration to a second speed. And a step of detecting the thickness of the coating agent layer on the substrate to be processed; and a third speed of rotating the substrate to be processed and the third speed based on the detected film thickness. Determining a second acceleration up to and rotating the substrate to be processed at the determined third speed and second acceleration. 5. The coating method according to claim 1, wherein said first speed is 100 to 500 rpm. p.
m. A coating method, characterized in that: 6. The coating method according to claim 1, wherein the second speed is 3000 to 6000 rpm.
p. m. A coating method, characterized in that: 7. The coating method according to claim 1, wherein the first acceleration is 30,000 to 50,000.
r. p. m. / Sec. 8. The coating method according to claim 4, wherein said third speed is 1000 to 4000 rpm. p. m. A coating method, characterized in that: 9. A holding unit for holding a substrate to be processed, a rotation driving unit for rotating the holding unit, a unit for supplying a coating agent to the substrate to be processed, and a film of a coating agent layer on the substrate to be processed. A coating apparatus comprising: means for detecting a thickness; and means for controlling a rotation speed and a rotation acceleration of the rotation driving means based on the detected film thickness of the coating agent layer. 10. A spin chuck that holds a substrate to be processed, a rotation drive mechanism that rotates the holding unit, a coating agent supply mechanism that supplies a coating agent to the substrate to be processed, and a coating agent on the substrate to be processed. A coating device, comprising: a sensor for detecting a film thickness of the layer; and a control unit for controlling a rotation speed and a rotation acceleration of the rotation drive mechanism based on the detected film thickness of the coating agent layer. . 11. A spin chuck for holding a substrate to be processed, a rotation drive mechanism for rotating the holding means, a coating agent supply mechanism for supplying a coating agent to the substrate to be processed, and a coating agent on the substrate to be processed. A coating apparatus, comprising: a sensor for detecting a weight of a layer; and a control unit for controlling a rotation speed and a rotation acceleration of the rotation drive mechanism based on the detected weight of the coating agent layer. 12. A spin chuck for holding a substrate to be processed, a rotation drive mechanism for rotating the holding means, a coating agent supply mechanism for supplying a coating agent to the substrate to be processed, and a coating agent on the substrate to be processed. A sensor that detects a change in the refractive index of the layer, and a control unit that controls the rotation speed and the rotation acceleration of the rotation drive mechanism based on the detected change in the refractive index of the coating agent layer. Coating device.