JP3593012B2 - Coating film forming apparatus and method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating film forming apparatus for forming a coating film by supplying a coating liquid such as a resist liquid onto a substrate such as a semiconductor wafer or an LCD substrate (glass substrate for a liquid crystal display), and a method therefor.
[0002]
[Prior art]
A technique called photolithography performed in a semiconductor device or LCD manufacturing process is to apply a resist solution to a substrate (for example, a semiconductor wafer) to form a resist film as a coating film, and expose the resist film using a photomask. After that, a resist pattern is obtained by performing a developing process.
[0003]
The application of the resist solution in the above-described steps is usually performed by a so-called spin coating method. In this method, the substrate is horizontally held by a rotatable spin chuck, the resist solution is supplied to the substrate from the nozzle above the center of the substrate, and the spin chuck is rotated, and the resist solution is diffused by centrifugal force. A coating film is formed on the entire substrate.
[0004]
In this method, since the rotation speed of the substrate corresponds to the centrifugal force, the thickness of the coating film of the resist solution (which is a liquid film at the time of application) depends on the rotation speed of the substrate. On the other hand, since exposure and development are performed under processing conditions corresponding to the thickness of the resist film, the thickness is required to be within a predetermined size. For this reason, the number of revolutions during the coating process (the number of rotations for shaking off) is adjusted so that a preset target film thickness can be obtained, and the coating process is performed. In some cases, the actual film thickness may deviate from the target film thickness due to factors such as the state of air pressure or the atmospheric pressure.
[0005]
Therefore, conventionally, for example, every time a certain number of substrates are processed, the substrate is withdrawn, the substrate is transported to a film thickness measurement unit provided separately from the coating film forming apparatus, and the film thickness is measured there. Then, it is determined whether or not the rotation speed of the spin chuck is appropriate. Based on the determination, the rotation speed (speed) is corrected so that the resist film thickness of the substrate subsequently sent to the production line approaches the target film thickness. I was
[0006]
[Problems to be solved by the invention]
However, in such a rotational speed correction work, there is no standard for determining the correction, so the amount of increase or decrease in the rotational speed is determined by trial and error based on the experience of the operator and the like. However, the measurement of the film thickness must be repeated while changing the number of rotations, so that the operation is troublesome, and the operation is difficult when no experienced person is present.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to form a coating film by a so-called spin coating method, and to correct a rotation speed of a substrate to obtain a target film thickness of the coating film. Is to automate.
[0008]
[Means for Solving the Problems]
The coating film forming apparatus according to the present invention, a carrier mounting portion on which a substrate carrier holding a plurality of substrates is mounted,
Transport means for receiving and transporting a substrate from a carrier mounted on the carrier mounting portion,
The substrate transported from the transporting means is held horizontally by the substrate holder, the coating liquid is supplied to the substrate, and the substrate holder is rotated to spread the coating liquid by the centrifugal force and apply the coating film on the substrate surface. A coating unit for forming
A film thickness measurement unit for measuring the thickness of the coating film formed on the substrate surface,
A data storage unit for storing rotation speed-thickness data indicating a relationship between the rotation speed of the substrate and the film thickness of the coating film during the coating process in the coating unit;
A condition setting unit for setting processing conditions including a target film thickness of the coating film in the coating unit and the number of rotations of the substrate during the coating process;
The target film thickness set by the condition setting unit, the film thickness measurement data of the coating film obtained by the measurement by the film thickness measurement unit, and the rotation speed-film thickness data stored in the data storage unit. A rotation speed correction unit that corrects the set value of the rotation speed so that the thickness of the coating film becomes a target value based on the rotation speed.
[0009]
“Based on film thickness measurement data” when performing the correction by the rotation speed correction unit means, for example, based on an average value of the film thickness on the substrate. The condition setting unit sets the number of rotations of the substrate at the time of the coating process, for example, based on the target film thickness of the coating film and the number of rotations-film thickness data.
[0010]
According to the present invention, the rotation speed-thickness data is prepared in advance, and the rotation speed correction unit calculates the rotation speed based on the data, the target film thickness, and the actual film thickness, for example, the average film thickness. Since the correction is performed, the operation of correcting the rotation speed can be automated, and the adjustment of the rotation speed can be easily performed.
[0011]
In the present invention, when the rotation speed correction unit determines that the film thickness distribution does not satisfy the film thickness distribution condition, an alarm for notifying an abnormal state may be output and the correction operation may be stopped. When it is determined that the film thickness distribution condition is not satisfied, for example, the difference between the maximum value and the minimum value of the film thickness is smaller than a predetermined value, or the standard deviation of the film thickness distribution is a predetermined value. Is less than If the average value of the film thickness on the substrate surface is within the allowable range with respect to the target film thickness, the rotation speed is not corrected, and the set value of the previous rotation speed is used as the set value of the subsequent rotation speed. You may. Further, when it is determined that the correction value of the rotational speed is out of the correction allowable value set in advance, an alarm may be output as an abnormal state and the correction operation may be stopped. When it is determined that the correction value of the rotation speed is within the correction allowable value, the operator is notified of the fact, and after receiving a correction selection instruction from the operator, the set value of the rotation speed is corrected. Is also good.
[0012]
The present invention is also realized as a method of forming a coating film, the method includes a step of setting a target film thickness of a coating film to be formed on a substrate in a coating unit and a rotation speed of the substrate during the coating process,
A step of supplying a coating liquid to the substrate by the coating unit and rotating the substrate along the horizontal plane at the number of revolutions set in the step, and spreading the coating liquid by the centrifugal force to form a coating film on the substrate surface; When,
Measuring the thickness of the coating film formed on the substrate surface,
Rotation speed-thickness data indicating the relationship between the rotation speed of the substrate and the film thickness of the coating film during the coating process prepared in advance, the target film thickness, and the film thickness of the coating film obtained by the measurement in the step. Correcting the set value of the number of revolutions based on the thickness measurement data so that the thickness of the coating film becomes a target value. Further, the above steps may be repeated until the thickness of the coating film falls within the allowable range of the target film thickness.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the coating film forming apparatus of the present invention is applied to a coating and developing apparatus will be described. The coating / developing device includes an apparatus main body for transporting and processing a substrate and a control unit. First, the apparatus main body will be briefly described. 1 and 2 are a plan view and a schematic view, respectively, showing the overall configuration of a resist pattern forming apparatus in which the coating and developing apparatus 100 is connected to an exposure apparatus 200.
[0014]
In the figure, reference numeral 11 denotes a carrier station for carrying in and out a carrier C containing a semiconductor wafer (hereinafter, referred to as a wafer) W, for example, 25 substrates. The carrier station 11 places the carrier C thereon. A carrier mounting section 12 and a delivery unit 13 are provided. The transfer means 13 is configured to take out the wafer W, which is a substrate, from the carrier C and deliver the taken out wafer W to the processing section S1 provided on the back side of the carrier station 11.
[0015]
A main transport unit 14 is provided at the center of the processing unit S1, and the coating unit 2 and the developing unit 15 are disposed on the right side of the processing unit S1, for example, when viewed from the carrier station 11 so as to surround the main transport unit 14. On the side, shelf units U1, U2, U3 in which heating / cooling system units and the like are stacked in multiple stages are arranged, respectively. In this example, two coating units 2 and two developing units 15 are provided, and the coating unit 2 is disposed on the lower side of the developing unit 15. In the shelf units U2, U3, and U4, a wafer transfer unit, a hydrophobizing unit, and the like, in addition to a heating unit and a cooling unit, are allocated vertically. The main transfer means 14 is configured to be able to move up and down, move back and forth, and rotate around a vertical axis, and has a role of transferring the wafer W between the shelf units U2, U3, U4, the coating unit 2 and the developing unit 15. . However, the transfer means 13 and the main transport means 14 are not shown in FIG. 2 for convenience.
[0016]
The processing section S1 is connected to the exposure apparatus 200 via an interface section S2. The interface unit S2 includes a delivery unit 16, a buffer cassette C0, and a film thickness measurement unit 3. The delivery unit 15 is movable up and down, left and right, back and forth, and rotatable around a vertical axis. The wafer W is transferred between the processing block S1, the exposure apparatus 200, the buffer cassette C0, and the film thickness measuring unit 3.
[0017]
The flow of the wafer in the pattern forming apparatus will be described. First, the carrier C is loaded into the carrier mounting portion 12 from the outside, and the transfer arm 13 takes out the wafer W from the inside of the carrier C. The wafer W is transferred from the transfer arm 13 to the main transfer arm 14 via the transfer unit EXT (see FIG. 2) of the shelf unit U2, and further transferred sequentially to the processing units of the shelf unit U2 (or U1, U3). A predetermined process such as a hydrophobizing process and a cooling process is performed. Subsequently, the wafer W is coated with a resist solution in the coating unit 2 and further heated to evaporate the solvent of the resist solution, and then transferred from the transfer unit, which is not visible in the drawing of the shelf unit U3, to the exposure apparatus 200 via the interface unit S2. Sent to When measuring the film thickness of the resist film formed on the wafer W, the wafer W is carried into the film thickness measuring unit 3 in the interface section S2.
[0018]
The wafer W exposed by the exposure device 200 is returned to the processing section S1 by the reverse route, transported to the developing unit 15 by the main transport arm 14, and subjected to development processing. More specifically, the wafer W is subjected to a heating process and a cooling process before the developing process. The developed wafer W is delivered to the delivery arm 12 along the reverse path, and is returned to the original carrier C placed on the carrier placement unit 12.
[0019]
Here, the coating unit 2 and the measuring unit 3 will be described. First, an example of the coating unit 2 will be described with reference to FIG. 3. Reference numeral 21 denotes a spin chuck as a substrate holding unit, which is configured to hold the wafer W horizontally by vacuum suction. The spin chuck 21 can be rotated around a vertical axis by a driving unit 22 including a motor and a lifting unit, and can be moved up and down. A liquid receiving cup 23 is provided around the spin chuck 21 and surrounds a side portion extending from the wafer W to the spin chuck 21 and has a concave portion formed over the entire lower side. Is connected to an exhaust pipe 24 and a drain pipe 25. A resist liquid supply nozzle 26 is provided above the liquid receiving cup 23, and the nozzle 26 is configured to be movable between the upper part of the center of the wafer W and the outside of the liquid receiving cup 23.
[0020]
In the coating unit 3 configured as described above, the wafer W is loaded by the main transfer unit 14 and transferred to the spin chuck 21. When the resist liquid is supplied from the nozzle 26 to the central portion of the wafer W and the spin chuck is rotated at a preset rotation number (rotational rotation number), the resist liquid spreads in the radial direction of the wafer W due to the centrifugal force. A liquid film of the resist liquid is formed on the surface of W, and the shaken off portion flows down to the liquid receiving cup 33. The drive unit 22 is controlled by the controller 20, and various conditions such as the number of revolutions of the spin chuck (the number of revolutions of the spin chuck) are set by the later-described control unit and instructed to the controller 20.
[0021]
As shown in FIG. 4, the film thickness measuring unit 3 provided in the interface section S2 includes a housing 31 having a transfer port 32 on a side surface, and a wafer W provided in the housing 31 for mounting a wafer W thereon. A mounting table 33, a driving mechanism 34 that makes the mounting table 33 rotatable and movable in the X and Y directions, and a light interference type film thickness meter 35 are provided. The optical interference type film thickness meter 35 includes a probe 35a provided so as to face the surface of the wafer W on the mounting table 33, an optical fiber 35b, and a spectroscope unit 35c including a spectroscope and a controller. That is, a spectrum is obtained based on the reflected light of the light applied to the surface of the wafer W, and the film thickness is detected based on the spectrum.
[0022]
In the film thickness measuring unit 3, the wafer W is moved in the X and Y directions, and the optical axis is positioned at a number of positions along the diameter of the wafer W by the probe 35a, so that the film thickness at each position is increased. Measured. In FIG. 4, reference numeral 30 denotes a computer, which controls the movement of the mounting table 33 in the X and Y directions by a driving mechanism 34 and processes signals obtained from the spectroscope unit 35c to form a film at each position of the wafer W. And a function of obtaining a film thickness distribution and calculating an average value of the film thickness.
[0023]
Further, in this example, the film thickness measuring unit 4 is configured to share a peripheral edge exposure device that exposes the peripheral portion of the wafer W exposed by the exposure device 200 in order to remove the peripheral resist. I have. That is, an exposure unit 36 is provided in the housing 31, and a line sensor 37 for detecting a peripheral portion of the wafer W is provided so as to vertically sandwich a passage area of the wafer W.
[0024]
In the present embodiment, the configuration in which the probe 35a is fixed and the wafer W is moved to measure the film thickness at each position of the wafer has been described, but the wafer W is fixed on the mounting table 33 and the probe 35a is driven by a driving unit ( (Not shown) to measure the film thickness at each position of the wafer.
[0025]
Referring back to FIG. 1, the coating / developing apparatus 100 includes a control unit 4 for managing a recipe of each processing unit. FIG. 5 shows the configuration of the control unit 4, which is actually configured by a CPU (Central Processing Unit), a program, a memory, and the like. However, it is assumed that each function is blocked and described as a component. The control unit 4 creates and manages recipes for each processing unit, and controls each processing unit according to the recipe.
(1) Setting of target film thickness of resist film (coating film) and rotation speed of wafer W in coating unit 2
(2) Creation of data (spin curve) indicating the relationship between the film thickness and the number of rotations
(3) Correction of the number of rotations based on the actual thickness, the target thickness, and the data of the resist film.
And so on. Therefore, the following description will be made with emphasis on the coating unit 2.
[0026]
In FIG. 5, 41 is a recipe creation unit, 42 is a recipe storage unit, and 43 is a recipe selection unit. The recipe creation unit 41 has a resist type, a target film thickness, for example, a target value of an average film thickness on a wafer surface, and a coating film formation. It is possible to input a recipe in which processing conditions necessary for the coating process such as the number of rotations of the wafer W (the number of rotations of the wafer W) and the rotation time are combined, and each recipe created here is a recipe. It is stored in the storage unit 42. The recipe creation section includes a recipe creation program and an operation screen for inputting and editing a recipe. A plurality of recipes are prepared according to a target coating film, and the operator selects a target recipe from the plurality of recipes stored in the recipe storage unit 43 by the recipe selection unit 43. B1 is a bus.
[0027]
The control section 4 includes a spin curve creating section 51 and a spin curve storing section 52. The spin curve indicates the number of rotations of the wafer W during the coating process in the coating unit 2 and the thickness of the resist film (the resist film after the solvent of the resist solution is volatilized) on the surface of the wafer W coated at the number of rotations. Rotational speed-film thickness data representing a correlation between, for example, the average film thickness obtained based on the measurement data, for example, an approximate expression representing the correlation, and the display screen has, for example, a horizontal axis and a vertical axis. Are shown as graphs showing the rotation speed and the film thickness, respectively. The spin curve creation section 51 includes a program for creating a spin curve and a display section for displaying a spin curve obtained by the program. In the spin curve creation mode, a plurality of monitor boards are used. A resist film is formed at various rotation speeds in the coating unit 2 using a certain monitor wafer, and the film thickness of each resist film is measured by the film thickness measurement unit 3 based on the rotation speed-film thickness data. It is configured to create a spin curve.
[0028]
The control unit 4 further includes an operation mode selection unit 44, a rotation speed correction unit 6, and an alarm generation unit 7. The operation mode selection unit 44 includes a processing mode for processing a product wafer, that is, a mode for controlling each step of coating, exposure, and development based on the recipe created by the recipe creation unit 41, and a spin card. The operation mode is selected, for example, on the operation panel of the apparatus from the operation mode. Further, even when the coating film is formed in accordance with the recipe, the resist liquid applied to the wafer surface may not have the expected thickness depending on the temperature, humidity, quality of the wafer, etc. The rotation speed is corrected based on the spin curve so that the film thickness becomes a target value. The alarm generation unit 7 is for generating an alarm when the film thickness distribution or the calculation result shows an abnormal value when a rotation speed correction program is operated, for example, a buzzer sound, It performs operations such as turning on an alarm lamp and displaying an alarm on an operation screen.
[0029]
Here, an example of a setting input screen for rotation number correction, which is one of the recipe creation screens of the coating unit 2, is shown in FIG. In this screen 40, the link spin curve name is the name of the spin curve used by the recipe. For example, since the relationship between the rotation speed and the film thickness is different if the type of the resist is different, the rotation speed is set in order to obtain the target film thickness target value (target film thickness). Must be determined based on the spin curve corresponding to the resist to be used. Since a plurality of spin curves are prepared in the spin curve storage section, the operator selects one of the spin curves linked to the recipe (used in the recipe) from the operator and inputs its name.
[0030]
The screen 40 can be used to input an average shift width, a range width, 3σ, and a rotation speed correction allowable value, in addition to the target film thickness of the resist film. The average shift width is an allowable range of the film thickness, and if the film thickness falls within this range, it is treated as a normal state. The range width is the difference between the maximum film thickness and the minimum film thickness in the film thickness distribution on the surface of the wafer W, and 3σ is a value three times the standard deviation in the film thickness distribution. If the actual film thickness distribution deviates from these set values when moved, it is handled as an abnormal state. The rotation speed correction allowable value is an abnormal value when a correction amount (rotation speed correction value) for correcting the current rotation speed is obtained by a rotation speed correction program and the correction amount is out of the value set here. It is intended to be handled as a state. That is, these values correspond to threshold values in each determination step when the rotational speed correction program is operated, and some of them are given numerical values as an example for convenience. The screen 40 is provided with a selection section 40a for selecting "Yes" or "No" for automatic correction of the number of revolutions. In the present embodiment, selecting "Yes" for automatic correction is performed. There is.
[0031]
The control unit 4 includes the coating unit 2, the developing unit 15, the heating / cooling unit 10 provided in the shelf units U 1, U 2, and U 3 to be controlled, the main transport unit 14, and the transfer units 13 and 16. And the like and the film thickness measuring unit 3 are connected via controllers 20, 15a, 10a, 8a and a computer 30, respectively.
[0032]
Next, the operation of the present embodiment will be described. Prior to forming a resist pattern by the above-described pattern forming apparatus, a recipe (coater recipe) for the coating unit 2 corresponding to the type of resist is created. In preparing the recipe, it is necessary to set the target film thickness of the resist film and the number of rotations of the wafer W when forming the coating film. This setting is performed according to the flow shown in FIG. First, when preparing the coater recipe R1, a target film thickness, for example, 7000 angstroms is input (step S1), and then the rotation speed and film thickness measurement data are measured using a monitor recipe substantially the same as this recipe R1. Is obtained (step S2). More specifically, in step S2, a spin curve creation mode is selected by the operation mode selection unit 44 shown in FIG. 5, and a plurality of monitor wafers, for example, bare wafers, which are monitor substrates, are prepared. The wafers are sequentially loaded into the coating unit 2, the number of rotations of each monitor wafer is set to various values, a resist as a coating liquid is coated on the surface, and the thickness of each resist film is measured by the film thickness measuring unit 3. This is the step of measuring. The measurement data of the film thickness is, for example, a film thickness distribution along the diameter of the wafer, and the above-described spin curve, which is the relationship between the average film thickness in the film thickness distribution and the number of rotations, is formed by the spin curve. It is created by the unit 51 and stored in the spin curve storage unit 52 (step S3). The spin curves are created by plotting, for example, at intervals of 40 rpm between 2000 and 3000 rpm.
[0033]
In the next step S4, it is determined whether or not the operator determines the number of rotations corresponding to the target film thickness of the recipe R1 based on the spin curve obtained in step S3. Then, the operator performs a decision operation on the operation panel, and in response thereto, obtains a rotation speed corresponding to a target film thickness, for example, 7000 angstroms, from the spin curve by a program stored in the recipe creation unit 41, and obtains the recipe R1. Is automatically set (step S5). If no decision is made, this flow is terminated. This step S5 is to set the number of revolutions when a spin curve is first created, for example, when starting up the apparatus or when using a new resist. However, when the operation is started, the spin curve is already set. Since a curve is created and the curve is to be retaken, the setting of the number of rotations has the meaning of correcting the number of rotations (absolute value correction). In FIG. 7, the term "absolute value correction" is used. When linking the recipe R1 to the created spin curve, for example, an alarm may be emitted to prompt confirmation.
[0034]
Next, the manner in which a resist solution is applied to the wafer W and the number of revolutions already set based on the thickness of the resist film is corrected will be described with reference to FIG. This rotation speed correction work may be performed, for example, by measuring the thickness of the resist film of the product wafer every time a predetermined number of product wafers are processed, and based on the measured data, or by using a bare wafer, for example. You may make it perform using a monitor wafer. First, the wafer W is loaded into the coating unit 2, and a resist solution is coated by spin coating as described above using, for example, the recipe R <b> 1 to form a coating film (step S <b> 1). The thickness measurement data of the coating film, for example, a film thickness distribution along the diameter of the wafer W is obtained (step S2).
[0035]
For example, the computer 30 in the film thickness measuring unit 3 calculates the range width or 3σ and the film thickness average value from the film thickness distribution and sends them to the control unit 4. FIG. 9 shows an example of the film thickness distribution. The range width is the difference between the maximum value and the minimum value of the film thickness, and 3σ is three times the standard deviation. The rotation speed corrector 6 determines, for example, whether the range width is within the set value of the range width already set on the setting screen shown in FIG. 6 (step S3), and if the range width is out of the set value. If it is determined that the apparatus is abnormal, an alarm is output from the alarm generation means 7 (step S4), and the correction operation is stopped by operating the operator, for example. If it is within the set value, the process proceeds to step S5. In the determination step of step S3, 3σ may be used instead of the range width, and the set value may be compared with the set value set on the input screen of FIG. 6, and if 3σ is within the set value, the process may proceed to step S5. The process may proceed to step S5 when both the range width and 3σ are within the set values.
[0036]
In step 5, it is determined whether or not the film thickness average value is within the average value shift width set on the input screen. If the film thickness average value is within the set value, it is not necessary to correct the rotation speed. Since the coating process may be performed using the set value, the correction program is ended, and if the value is outside the set value, the process proceeds to step S6. The average value shift width indicates an allowable range in which even if the average film thickness does not completely match the target film thickness, the average shift value is within the allowable range and does not affect the process. FIG. 10 is a diagram showing the correspondence between the spin curve and the permissible range and the rotational speed correction range. In this example, when the target film thickness is 7000 Å, the average value shift width (permissible range) is 6,970. It is set to ~ 7030 angstroms.
[0037]
In step S6, the rotation speed is corrected using the spin curve linked to the recipe R1 as follows. For example, when the average film thickness a is different from the target film thickness a0, for example, a spin curve D1 linked to the recipe R1 is called as shown in FIG. , And the deviation from the current swing-out rotation speed p0 (the shake-out rotation speed which should have become the target film thickness a0) p0 is calculated.
[0038]
Therefore, it was found that the result of application at the rotation speed p0 set in the recipe R1 was the film thickness a, but according to the spin curve D1, the rotation speed corresponding to the film thickness a was p. Therefore, it can be considered that the amount of the resist solution shake-off decreased by the amount (p0-p) corresponding to the decrease in the rotation speed, and the film thickness increased. Therefore, the rotation speed correction unit 6 relatively decreases the film thickness by adding the correction value Apm (p0-p) to the current rotation speed p0 as shown in FIG. 12, whereby the film thickness becomes the target value a0. Try to get closer to. However, if the corrected rotation speed is too large or too small, there is a risk that the coating unit 2 may not be able to apply the resist with the target film thickness. It is determined whether or not the rotation speed is within the correction allowable value. If the rotation speed is not within the correction allowable value, the flow proceeds to step S4 to output an alarm. If the rotation speed is within the correction allowable value, the flow proceeds to step S8. The rotation speed set value of the recipe R1 is corrected by the correction value Apm. Thereafter, a resist liquid application process is performed using the corrected rotation speed.
[0039]
In the above-described embodiment, the film thickness measurement unit 3 is provided in the coating and developing apparatus 100, and the thickness measurement data of the resist film obtained here is taken into the control unit 4, while the coater recipe and the spin card are previously stored. And a rotation speed at the time of coating processing based on the spin curve, the film thickness measurement data, and a target film thickness set by a coat recipe using a rotation speed correction program. I am trying to correct it. Therefore, when the thickness of the resist film formed on the surface of the wafer W deviates from the target thickness, the rotation speed can be automatically corrected, and the operation of correcting the rotation speed becomes easy, and the burden on the operator is increased. Can be reduced and appropriate correction can be performed.
[0040]
When the difference or standard deviation between the maximum film thickness and the minimum film thickness in the film thickness distribution on the surface of the wafer W is out of a predetermined value, an abnormality in the coating unit 2 or the heating unit, an abnormality in the film thickness measuring unit 3, Or, because there is a possibility of an abnormality in the atmosphere control such as temperature and humidity, the abnormality is judged to be abnormal, the correction work is stopped, and the operator is notified. Therefore, the abnormality of the device can be detected promptly, and the process proceeds in an abnormal state. There is no danger. Also, when the correction value of the calculated rotational speed is out of the predetermined range, there is a high possibility that the device is abnormal similarly. In this case, the correction work is stopped, so that the process proceeds in an abnormal state. There is no danger.
[0041]
Returning to the input screen of FIG. 6, in the above-described example, the selection unit 40a is described as selecting "Yes" for automatic correction. However, when "No" is selected for automatic correction, the rotation speed is corrected. The flow is as shown in FIG. This flow is the same as that of the above-described embodiment up to step S7, but when the correction of the rotation speed is within the allowable range, the rotation speed is not automatically corrected, and the alarm is generated at step S8. The rotation number is corrected when the operator selects the correction in step S9, and the correction operation is stopped when the correction is not selected in step S9. In this example, the operator determines whether or not to perform correction by looking at the rotational speed after correction, and the system reflects the experience of the operator.
[0042]
Further, according to the present invention, after the rotation speed is corrected, a resist solution is applied at the corrected rotation speed, and then the film thickness of the resist film is measured. It is determined whether or not the rotation speed is within the allowable range. If the rotation speed is not within the allowable range, the rotation speed is corrected again, and the correction work is repeated until the average film thickness falls within the allowable range with respect to the target film thickness. Good. FIG. 14 is a flow chart showing such an example. The flow up to step S8 is the same as that in FIG. 8, but after correction, the flow returns to step S1. However, in order to limit the number of corrections to a certain number, a step S9 for incrementing a count value k for counting the number of corrections by one and a step S10 for determining whether the count value k exceeds a set number of times (for example, “3”) are provided. When the number of corrections exceeds a set value, an alarm is output, and the subsequent action is left to the operator's judgment.
[0043]
In the above, the substrate used in the present embodiment may be an LCD substrate. The coating liquid is not limited to the resist liquid, but may be an interlayer insulating material, a low dielectric material, a ferroelectric material, a wiring material, an organic metal material, a metal paste, or the like.
[0044]
【The invention's effect】
According to the present invention, when performing so-called spin coating in which a substrate is rotated to form a coating film, an operation of correcting the number of rotations of the substrate to obtain a target film thickness of the coating film can be automated, and Appropriate rotation speed correction can be performed.
[Brief description of the drawings]
FIG. 1 is a plan view showing an entire configuration of an embodiment of a coating film forming apparatus according to the present invention.
FIG. 2 is a perspective view showing an overview of an embodiment of a coating film forming apparatus according to the present invention.
FIG. 3 is a vertical sectional side view showing a main part of a coating unit.
FIG. 4 is a vertical sectional side view showing a main part of a film thickness measuring unit.
FIG. 5 is a block diagram illustrating a control unit used in the embodiment.
FIG. 6 is an explanatory diagram showing a part of an input screen in a recipe creation unit.
FIG. 7 is a flowchart showing how to set the number of revolutions in the embodiment.
FIG. 8 is a flowchart showing how the rotation speed is corrected in the embodiment.
FIG. 9 is an explanatory diagram showing an example of a film thickness distribution of a resist film.
FIG. 10 is an explanatory diagram showing an average shift width of film thickness and an allowable correction value used when correcting the number of rotations.
FIG. 11 is an explanatory diagram showing a state of correcting the number of rotations in the embodiment.
FIG. 12 is an explanatory diagram showing a state of correcting the number of rotations in the embodiment.
FIG. 13 is a flowchart showing how to set the number of revolutions in another embodiment.
FIG. 14 is a flowchart showing a state in which the rotation speed is corrected in still another embodiment.
[Explanation of symbols]
100 Coating and developing equipment
200 Exposure equipment
W semiconductor wafer
12 Carrier mounting part
14 Main transfer arm
15 Developing unit
2 Coating unit
20 Controller
21 Spin chuck
22 Drive mechanism
26 nozzles
3 Film thickness measurement unit
35 Optical interference type film thickness meter
4 control unit
40 Recipe input screen
41 Recipe making section
42 Recipe storage
43 Recipe selection section
44 Operation mode selection section
51 Spin curve generator
52 Spin curve storage
6 Rotation speed correction unit
7 Alarm generator

Claims (7)

A carrier mounting portion on which a substrate carrier holding a plurality of substrates is mounted,
Transport means for receiving and transporting a substrate from a carrier mounted on the carrier mounting portion,
The substrate transported from the transporting means is held horizontally by the substrate holder, the coating liquid is supplied to the substrate, and the substrate holder is rotated to spread the coating liquid by the centrifugal force and apply the coating film on the substrate surface. A coating unit for forming
A film thickness measurement unit for measuring the thickness of the coating film formed on the substrate surface,
A data storage unit for storing rotation speed-thickness data indicating a relationship between the rotation speed of the substrate and the film thickness of the coating film during the coating process in the coating unit;
A condition setting unit for setting processing conditions including a target film thickness of the coating film in the coating unit and the number of rotations of the substrate during the coating process;
The target film thickness set by the condition setting unit, the film thickness measurement data of the coating film obtained by the measurement by the film thickness measurement unit, and the rotation speed-film thickness data stored in the data storage unit. A rotation speed correction unit that corrects the set value of the rotation speed so that the thickness of the coating film becomes a target value based on the data,
The rotation speed correction unit includes means for determining whether the correction value of the rotation speed is within a preset correction allowable value,
A coating film forming apparatus, further comprising means for outputting a warning when the rotation speed correction unit determines that the correction value of the rotation speed is out of the correction allowable value, as an abnormal state . The coating film forming apparatus according to claim 1, wherein the correction allowable value is set by the condition setting unit. When the rotation speed correction unit determines that the correction value of the rotation speed is within the correction allowable value, the rotation speed correction unit notifies the operator of the fact, and receives a correction selection instruction from the operator, and then sets the rotation speed set value. The coating film forming apparatus according to claim 1, wherein the coating film forming apparatus is configured to correct the following. A carrier mounting portion on which a substrate carrier holding a plurality of substrates is mounted,
Transport means for receiving and transporting a substrate from a carrier mounted on the carrier mounting portion,
The substrate transported from the transporting means is held horizontally by a substrate holder, and the coating liquid is supplied to the substrate and the substrate holder is rotated to spread the coating liquid by the centrifugal force, thereby forming a coating film on the substrate surface. A coating unit for forming
A film thickness measurement unit for measuring the thickness of the coating film formed on the substrate surface,
A data storage unit for storing rotation speed-thickness data indicating a relationship between the rotation speed of the substrate and the film thickness of the coating film during the coating process in the coating unit;
A condition setting unit for setting processing conditions including a target film thickness of the coating film in the coating unit and the number of rotations of the substrate during the coating process;
The target film thickness set by the condition setting unit, the film thickness measurement data of the coating film obtained by the measurement by the film thickness measurement unit, and the rotation speed-film thickness data stored in the data storage unit. A rotation speed correction unit that corrects the set value of the rotation speed so that the film thickness of the coating film becomes a target value based on the data, and a coating film forming apparatus,
The rotation speed correction unit includes means for determining whether the correction value of the rotation speed is within a preset correction allowable value,
When the rotation speed correction unit determines that the correction value of the rotation speed is out of the correction allowable value, the rotation speed correction is repeatedly performed until the thickness of the coating film reaches the target value. Film forming equipment . A step of setting a target film thickness of a coating film to be formed on the substrate in the coating unit and the number of rotations of the substrate during the coating process;
The coating liquid is supplied to the substrate by the coating unit and the substrate is rotated along the horizontal plane at the number of revolutions set in the step, and the coating liquid is spread by the centrifugal force to form a coating film on the substrate surface. Forming,
Measuring the thickness of the coating film formed on the substrate surface,
Rotation speed-thickness data indicating the relationship between the rotation speed of the substrate and the film thickness of the coating film during the coating process prepared in advance, the target film thickness, and the film thickness of the coating film obtained by the measurement in the step. Correcting the set value of the number of revolutions based on the thickness measurement data so that the film thickness of the coating film becomes a target value;
A step of determining whether or not the correction value of the rotation speed is within a preset correction allowable value;
Outputting a warning when it is determined that the value is larger than the correction allowable value as an abnormal state. When it is determined that the correction value of the rotation speed is within the correction allowable value, the operator is notified of the fact, and after receiving a correction selection instruction from the operator, the set value of the rotation speed is corrected. The method for forming a coating film according to claim 5. (A) setting a target film thickness of a coating film to be formed on the substrate in the coating unit and a rotation speed of the substrate during the coating process;
(B) supplying the coating liquid to the substrate in the coating unit and rotating the substrate along the horizontal plane at the rotation speed set in the above step or the corrected rotation speed to spread the coating liquid by the centrifugal force; Forming a coating film on the substrate surface;
(C) measuring the thickness of the coating film formed on the substrate surface;
(D) determining whether the thickness of the coating film is within an allowable range of the target film thickness;
(E) When the film thickness of the coating film does not fall within the allowable range of the target film thickness, the rotation speed-film thickness data indicating the relationship between the rotation speed of the substrate and the film thickness of the coating film at the time of the coating process prepared in advance. Set value of the number of revolutions so that the film thickness of the coating film becomes a target value based on the data, the target film thickness, and the film thickness measurement data of the coating film obtained in the step. And correcting the
  A method for forming a coating film, wherein the steps (e), (b), (c) and (d) are repeated until the thickness of the coating film falls within an allowable range of the target film thickness.

Images