JP2004361165A - Liquid detection method, liquid application method, and liquid application apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid detection method, a liquid application method, and a liquid application apparatus capable of easily and accurately grasping the amount of a liquid dropped onto a substrate or the thickness of liquid application applied to the substrate. <P>SOLUTION: A resist liquid is dropped onto the surface of a wafer 1. By rotating the wafer 1 and diffusing the resist liquid by a centrifugal force, the resist liquid having uniform thickness is applied onto the surface of the wafer 1 in a spin coater 100. The spin coater 100 is provided with: an electrically conductive rotating stage 10 for rotatably supporting the back surface of the wafer 1; an electrode plate 20 provided in such a way as to be opposed to the rotating stage 10 at a prescribed separating interval; and a measuring part 40 having one end connected to the rotating stage 10 and the other end connected to the electrode plate 20 for measuring electrostatic capacitance between the rotating stage 10 and the electrode plate 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid detection method, a liquid application method, and a liquid application apparatus, and is particularly suitable for application to a step of applying a resist or SOG (spin on glass) on a semiconductor wafer and an application apparatus thereof. The present invention relates to a liquid detection method, a liquid application method, and a liquid application device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a manufacturing process of a semiconductor device, a photolithography technique has been used to transfer a circuit pattern onto a wafer. In this photolithography technique, first, a resist film is applied and formed on a wafer by a resist coating apparatus. Next, the resist film is heated by a heat treatment apparatus, subjected to a pre-bake treatment, cooled, and exposed to a predetermined pattern by an exposure apparatus. Further, a developing solution is applied to the exposed wafer by a developing device and developed. Then, the developing solution is washed away with the rinsing solution, and a resist pattern having a predetermined shape is formed on the wafer.
[0003]
One of the factors affecting the processing accuracy of the resist pattern formed in this way is the thickness of the resist film. The thickness of the resist film greatly depends on the amount of the resist dropped on the wafer (hereinafter, referred to as a dropped amount).
For this reason, in the resist film forming process, the amount of the resist solution dropped in the resist coating device at one time was periodically measured, and when the value was out of the standard, the resist coating device was adjusted. .
[0004]
Specifically, first, an operator periodically measures the amount of the resist solution dropped using a measuring cylinder. Next, when the measured value is out of the standard, the discharge pressure of the discharge pump of the resist coating apparatus is adjusted to adjust the amount of the resist solution dropped per time. Then, the amount of the resist solution dropped is measured again using a measuring cylinder, and it is checked whether the value is within the standard. Here, if the amount of the resist solution dropped did not meet the standard, the above operation was repeated.
[0005]
[Patent Document 1]
JP 2000-84468 A
[0006]
[Problems to be solved by the invention]
By the way, in the resist film forming process according to the conventional example, the measurement of the dripping amount of the resist solution was manually performed by an operator using a measuring cylinder. For this reason, there is a problem that the reading value of the measuring cylinder and the like differ between operators, and a measurement error is large.
[0007]
In addition, the measurement of the drop amount is an operation that places a heavy burden on an operator and, when the number of measurements is large, significantly reduces the processing capability of the process. For this reason, it is not practical to measure the amount of the resist solution dripped every time one wafer is processed or each time a wafer is processed in a lot. For example, the dripping amount is measured only once to three times a day. The amount could not be determined. For this reason, the drop amount changes between the measurements, and there is a possibility that the application of the resist solution on the surface of the wafer may become uneven, the thickness of the application may be large, and the like.
[0008]
As one means for solving such a problem, for example, Patent Literature 1 discloses a resist coating apparatus capable of monitoring a change in chuck weight with time. However, the resist coating apparatus described in Patent Document 1 has a problem that the structure of a measuring mechanism for measuring the weight of the chuck is complicated. Further, the mechanism disclosed in Patent Document 1 is susceptible to the fluctuation of the weight of the lubricating oil poured into the bearing portion and the like, and has a problem that it is difficult to accurately measure the weight of the resist solution. If the weight of the resist solution cannot be measured accurately, there is a possibility that an abnormality in the drop amount or an abnormality in the coating thickness may be overlooked.
[0009]
Accordingly, the present invention has been made to solve such a problem, and a liquid detection method capable of easily and accurately grasping the amount of liquid dropped on a substrate or the applied thickness of liquid applied to a substrate. It is another object of the present invention to provide a liquid application method and a liquid application device.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, according to the first liquid detection method of the present invention, a state in which a substrate on which a liquid is dropped on a surface is placed on a conductive support, Measuring the capacitance between the support plate and the electrode plate provided on the opposite side of the substrate with respect to the substrate, and obtaining the amount of liquid on the surface of the substrate based on the measured capacitance. It is characterized by the following.
[0011]
Here, obtaining the amount of the liquid is a concept including calculating the value of the amount and determining whether the amount is within the standard.
When all of the liquid dropped on the substrate surface is on the substrate surface, the amount of the liquid dropped and the support base and the electrode plate that make the substrate on which the liquid is dropped a part of the dielectric are used. There is a correlation between the capacitance of the capacitor. For example, in FIG. 3A, the horizontal axis represents the amount of liquid dropped, and the vertical axis represents the capacitance of a capacitor having a substrate on which the liquid is dropped as a part of the dielectric. When the separation distance between the support base and the electrode plate, the thickness of the substrate itself, and the like are constant regardless of the amount of the liquid to be dropped, as shown in FIG. As the amount increases, the capacitance of this capacitor decreases.
[0012]
According to the first liquid detection method of the present invention, by measuring the capacitance of a capacitor in which a substrate that has the dropped liquid on its surface is part of a dielectric, the liquid is dropped. The amount can be easily and accurately grasped. Therefore, an abnormality in the amount of dripping can be found immediately.
In a second liquid detection method according to the present invention, a state in which a substrate having a liquid applied to a uniform thickness on a surface is placed on a conductive support, and the support and the substrate are sandwiched therebetween. It is characterized in that the capacitance between the support and the electrode plate provided on the opposite side is measured, and the coating thickness of the liquid on the surface of the substrate is obtained based on the measured capacitance. Things.
[0013]
Here, obtaining the coating thickness is a concept including calculating the value of the coating thickness and determining whether the coating thickness is within the standard.
There is a correlation between the coating thickness of the liquid on the substrate surface and the capacitance of a capacitor composed of an electrode plate and a support base having the substrate coated with the liquid as a part of the dielectric. For example, in FIG. 3B, the horizontal axis indicates the liquid application thickness, and the vertical axis indicates the capacitance of a capacitor having a substrate on which the liquid is applied as a part of the dielectric. When the separation distance between the support and the electrode plate and the thickness of the substrate itself are constant irrespective of the amount of the liquid to be dropped, as shown in FIG. The capacitance of this capacitor is reduced.
[0014]
According to the second liquid detection method according to the present invention, by measuring the capacitance of a capacitor having a part of a dielectric, the substrate having the liquid applied on its surface, the applied thickness of the liquid can be simplified. And it can be grasped accurately. Therefore, an abnormality in the thickness of the applied liquid can be immediately detected.
The first liquid application method according to the present invention, the step of mounting the substrate on a conductive support, and the step of dropping a predetermined liquid on the surface of the substrate mounted on the support, In a state where the substrate on which the liquid has been dropped is placed on a support, the capacitance between the support and an electrode plate provided on the opposite side of the support with the substrate therebetween is measured. A step of determining the amount of liquid on the surface of the substrate based on the measured capacitance; and, after determining the amount of liquid, dropping the liquid dropped on the surface of the substrate onto the surface of the substrate. And applying a uniform thickness on the top.
[0015]
According to the first liquid application method according to the present invention, the amount of liquid dropped on the surface of the substrate can be easily and accurately grasped, so that an abnormality in the dropped amount can be immediately found. Therefore, only the substrate having an appropriate amount of liquid on the surface can be flowed to the step of applying the liquid.
The second liquid application method according to the present invention, the step of mounting the substrate on a conductive support, the step of dropping a predetermined liquid on the surface of the substrate mounted on the support, A step of applying the liquid on the surface of the substrate to a uniform thickness, and holding the substrate on which the liquid is applied to a uniform thickness while holding the substrate on the support. Measuring the capacitance between the support and the electrode plate provided on the opposite side, and obtaining the coating thickness of the liquid on the surface of the substrate based on the measured capacitance. And the following.
[0016]
According to the second liquid application method according to the present invention, the thickness of the liquid applied on the surface of the substrate can be easily and accurately grasped, so that an abnormality in the applied thickness of the liquid can be immediately detected. Therefore, the outflow of the substrate having an abnormal coating thickness can be prevented.
The first liquid coating apparatus according to the present invention is configured to drop a predetermined liquid on the surface of a substrate, rotate the substrate, and diffuse the liquid by centrifugal force, thereby causing the liquid to spread on the surface of the substrate. In a liquid coating apparatus for applying a uniform thickness, a conductive rotating stage rotatably supporting the back surface of the substrate, and an electrode plate provided to face the rotating stage with a predetermined separation distance And a measuring unit connected to the rotating stage at one end and connected to the electrode plate at the other end, and measuring a capacitance between the rotating stage and the electrode plate. It is.
[0017]
ADVANTAGE OF THE INVENTION According to the 1st liquid application apparatus which concerns on this invention, the capacitance between the said rotation stage and an electrode plate can be measured in the state which mounted the substrate in which the liquid was dripped on the rotation stage. Therefore, the amount of liquid dropped on the surface of the substrate can be easily and accurately grasped. In addition, the capacitance between the rotating stage and the electrode plate can be measured while the substrate coated with the liquid having a uniform thickness is placed on the rotating stage. In this case, the thickness of the applied liquid can be easily and accurately grasped.
[0018]
In the second liquid application apparatus according to the present invention, in the above-described first liquid application apparatus, the measuring unit may be configured such that the substrate on which the liquid is dropped is placed on the rotation stage, and the rotation stage, the electrode plate, The capacitance is measured during the measurement.
According to the second liquid application device according to the present invention, the amount of liquid dropped on the surface of the substrate can be easily and accurately grasped, and an abnormality in the amount of dropped liquid can be immediately detected.
[0019]
In a third liquid application device according to the present invention, in the first and second liquid application devices described above, the measuring unit may include a substrate on which a liquid is applied with a uniform thickness placed on a rotary stage. And measuring the capacitance between the rotating stage and the electrode plate.
According to the third liquid application device of the present invention, the applied thickness of the liquid on the surface of the substrate can be easily and accurately grasped, and an abnormality in the applied thickness of the liquid can be immediately detected. Therefore, as compared with the first and second liquid application devices, both the liquid drop amount and the application thickness can be monitored, so that the occurrence of an abnormality in the liquid application process can be detected with higher detection ability. can do. Thereby, outflow of defective products can be prevented, and the quality of the liquid coating process can be further improved.
[0020]
In a fourth liquid application apparatus according to the present invention, in the first to third liquid application apparatuses described above, the measuring unit may perform the rotation while the substrate before the liquid is dropped is placed on a rotation stage. It is characterized in that the capacitance between the stage and the electrode plate is measured.
Here, the dielectric constant of the substrate itself depends on, for example, the type of the substrate, the type of a thin film formed on the substrate, and the like. Also, the thickness of the substrate itself usually differs slightly between the plurality of substrates.
[0021]
According to the fourth liquid application device of the present invention, the value of the capacitance before the liquid is dropped can be grasped as the initial value, so that the dielectric constant and the thickness of the substrate itself are different between the plurality of substrates. In this case, the difference between the initial value and the capacitance measured after the liquid is dropped (or applied) can be used to easily and accurately determine the amount of the liquid dropped (or the coating thickness). it can.
[0022]
The fifth liquid application device according to the present invention is the liquid application device according to any one of the second to fourth liquid application devices described above, wherein the capacitance measured by the measurement unit in a state where the substrate on which the liquid is dropped is mounted on the rotary stage. A dripping amount control unit for acquiring a measured value and changing a dripping amount of the liquid according to the acquired measured value is provided.
Here, the liquid is, for example, a resist liquid or a liquid for forming SOG (a liquid obtained by dissolving SiO2 in an organic solvent such as alcohol), and these liquids are usually dropped from a nozzle of a liquid coating apparatus. is there. Since such a resist solution or the like has a certain degree of viscosity and has a property of being easily dried, the tip of the nozzle is easily clogged.
[0023]
Therefore, when performing so-called single-wafer processing in which a plurality of substrates are continuously processed one by one, as the number of processed substrates increases, the tip of the nozzle is gradually clogged and the resist solution is dropped. The amount tends to decrease gradually.
According to the fifth liquid application apparatus of the present invention, even when a plurality of substrates (for example, one lot) are subjected to single-wafer processing, the amount of liquid dropped on the surface of the substrate is made to approach a constant value. The drop amount can be controlled during the single-wafer processing. Therefore, it is possible to reduce the variation in the drop amount within a lot.
[0024]
In the sixth liquid application apparatus according to the present invention, in the third to fifth liquid application apparatuses described above, the measurement unit measures the substrate in a state where the substrate on which the liquid is applied to a uniform thickness is placed on a rotary stage. And a rotation controller that changes the rotation speed and / or rotation time of the rotary stage in accordance with the acquired measured value of the capacitance.
[0025]
According to the sixth liquid application apparatus of the present invention, even when a plurality of substrates (for example, one lot) are subjected to single-wafer processing, the rotation stage is controlled so that the applied thickness of the liquid on the surface of the substrates approaches a constant value. Both or both the rotation speed and the rotation time can be changed during the single-wafer processing, and the number of rotations can be changed. Therefore, it is possible to reduce the variation in the coating thickness within a lot.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a liquid detection method, a liquid application method, and a liquid application apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating a configuration example of a spin coater 100 according to an embodiment of the present invention. The spin coater 100 is an apparatus for forming a thin resist film on the wafer 1 by dripping a resist solution onto the wafer 1 and rotating the wafer 1 at a high speed. The wafer 1 is, for example, a silicon wafer, an SOI (silicon on insulator) wafer, a glass wafer, or the like. The thickness of the wafer 1 is, for example, about 700 [μm].
[0027]
As shown in FIG. 1, the spin coater 100 includes a rotating stage 10, an electrode plate 20, an ejection nozzle 30, a measuring unit 40 for measuring capacitance, a control unit 60, a data storage unit 62, a display 64 and the like.
Among these, the rotary stage 10 rotatably supports the back surface of the wafer 1. A large number of holes are provided on a surface of the rotary stage 10 that contacts the rear surface of the wafer 1 (hereinafter, referred to as a contact surface). These holes are connected to a vacuum pump (not shown). When the wafer 1 is placed on the rotary stage 10 and vacuum is drawn through these holes, the back surface of the wafer 1 is attracted to the contact surface of the rotary stage 10. The rotary stage 10 is made of a metal material.
[0028]
As shown in FIG. 1, the electrode plate 20 is provided above the rotary stage 10 so as to face the contact surface of the rotary stage 10. In FIG. 1, the electrode plate 20 is separated from the rotary stage 10 by, for example, about several to several tens [mm]. When the wafer 1 is placed on the rotating stage 10, the wafer 1 is sandwiched between the rotating stage 10 and the electrode plate 20 with an air layer having a predetermined thickness between the wafer 1 and the electrode plate 20. Become. In the center of the electrode plate 20, a penetrating opening is provided. The electrode plate 20 is made of a metal material.
[0029]
Further, the discharge nozzle 30 is provided through an opening at the center of the electrode plate 20, and the discharge port thereof faces the rotary stage 10. The discharge nozzle 30 is connected to a pressurized container (not shown) for storing a resist solution. The resist solution in the pressurized container is pumped from the pressurized container to the discharge port of the discharge nozzle 30 by the operation of a pressure pump (not shown). Then, the resist liquid is dropped from the discharge port onto the surface of the wafer 1 placed on the rotary stage 10.
[0030]
As shown in FIG. 1, the measuring section 40 has one end connected to the rotary stage 10 and the other end connected to the electrode plate 20. The measurement unit 40 includes a voltage application unit 42, a capacitance meter 44, and the like. The capacitance between the rotating stage 10 and the electrode plate 20 is measured by the measuring unit 40.
As shown in FIG. 1, the main body 50 of the spin coater 100 is configured by the rotary stage 10, the electrode plate 20, the discharge nozzle 30, the measuring unit 40 and the like.
[0031]
Further, the control unit 60 shown in FIG. 1 includes a CPU (central processing unit) and the like, and is connected to the main body 50 of the spin coater 100 by wire or wirelessly. The operation of the main body 50 is controlled by the control unit 60. The data storage unit 62 includes a random access memory (RAM), a read only memory (ROM), and the like, and performs data write and read processing with the control unit 60. In the data storage unit 62, for example, a processing sequence of the spin coater 100 is stored. Further, the capacitance value and the like measured by the measuring unit 40 are also stored.
[0032]
Further, the display 64 is, for example, a liquid crystal display device, and is connected to the control unit 60. The display 64 is capable of displaying the processing state of the spin coater 100 (the selected processing sequence, step, rotation speed of the rotating stage 10, the number of processed sheets, and the like), as well as the measured capacitance value and the like. .
FIG. 2 is a flowchart showing a method for forming a resist film using the spin coater 100. Next, a method of forming a resist film on the surface of the wafer 1 using the spin coater 100 shown in FIG. 1 and along the flowchart of FIG. 2 will be described. In this description, it is assumed that all the processes in steps 1 to 10 in FIG.
[0033]
First, in step (S) 1 of FIG. 2, a product or dummy wafer 1 is transported onto the rotary stage 10 by a transport system (not shown). Next, a vacuum pump (not shown) is operated to adsorb the back surface of the wafer 1 to the contact surface of the rotary stage 10.
Next, in step 2 of FIG. 2, with the wafer 1 placed on the rotary stage 10, the capacitance (C ₀ ) Is measured. The measurement of the capacitance is performed by the measurement unit 40 in response to a control signal from the control unit 60. Then, a measured value C obtained by the measurement of the capacitance is obtained. ₀ Is stored in the data storage unit 62.
[0034]
Next, in step 3 of FIG. 2, a predetermined amount of resist liquid is dropped from the discharge nozzle 30 onto the surface of the wafer 10. Then, in step 4 of FIG. 2, with the wafer 1 on which the resist solution has been dropped placed on the rotary stage 10, the capacitance (C) between the rotary stage 10 and the electrode plate 20 is increased. ₁ ) Is measured. The measurement of the capacitance is performed by the measurement unit 40 in response to a control signal from the control unit 60. And the measured value C of this capacitance is ₁ Is stored in the data storage unit 62.
[0035]
Next, in step 5 of FIG. ₀ , C ₁ Are read out from the data storage unit 62 to the control unit 60, and the difference ΔC (= C ₀ -C ₁ ) Is calculated by the control unit 60. Before and after this calculation, the standard ΔC _spec From the data storage unit 62 to the control unit 60. Then, the difference ΔC between the measured values is equal to the standard ΔC. _spec It is determined by the control unit 60 whether or not it is within.
[0036]
Here, if the difference ΔC between the measured values is the standard ΔC _spec If it is out of the range, the process proceeds to step 9 in FIG. 2 to end the resist film forming process in the spin coater 100. At this time, an abnormality notification (alarm 1) is displayed on the display 64 of the spin coater 100 for the operator.
The reason why the difference ΔC in the measured values is out of the standard may be that the resist solution is excessively or excessively dropped on the surface of the wafer 10 in step 3 of FIG. Therefore, when the alarm 1 is displayed, the operator stops the test processing or the product processing using the spin coater 100, checks the amount of the resist liquid dropped, and adjusts the amount of the resist liquid as necessary. Then, after adjusting the drop amount or the like, the test processing using the spin coater 100 or the product processing is restarted.
[0037]
If ΔC is within the standard in step 5 of FIG. 2, the process proceeds to step 6 of FIG. In step 6 of FIG. 2, the wafer 1 placed on the rotary stage 10 is rotated at a predetermined rotation speed for a predetermined time, and the resist solution dropped on the surface of the wafer 1 is centrifugally applied to the wafer 1. Diffuse on the surface of Thus, a resist solution is applied to a uniform thickness on the surface of the wafer 1 to form a resist film.
[0038]
Next, the process proceeds to step 7 in FIG. In this step 7, in a state where the wafer 1 on which the resist film is formed is placed on the rotating stage 10, the capacitance (C) between the rotating stage 10 and the electrode plate 20 is increased. ₂ ) Is measured. The measurement of the capacitance is performed by the measurement unit 40 in response to a control signal from the control unit 60. And the measured value C of this capacitance is ₂ Is stored in the data storage unit 62.
[0039]
Next, in step 8 of FIG. ₀ And C ₂ Are read from the data storage unit 62 to the control unit 60, and the difference ΔC ′ (= C ₀ -C ₂ ) Is calculated by the control unit 60. Before and after this calculation, the standard ΔC ′ _spec From the data storage unit 62 to the control unit 60. The difference ΔC ′ between the measured values is the standard ΔC ′. _spec It is determined by the control unit 60 whether or not it is within.
[0040]
Here, if the difference ΔC ′ between the measured values is the standard ΔC ′ _spec If it is out of the range, the process proceeds to step 10 in FIG. 2 to end the resist film forming process in the spin coater 100. At this time, an abnormality notification (alarm 2) is displayed on the display 64 of the spin coater 100 for the operator.
The reason that the difference ΔC ′ in the measured values is out of the standard may be that the thickness (coating thickness) of the resist film formed in step 6 in FIG. 2 is too thick or too thin. Therefore, when the alarm 2 is displayed, the operator stops the test processing or the product processing using the spin coater 100, checks the rotation speed and the rotation time of the turntable 10, and if necessary, checks the rotation speed. And rotation time. Then, after adjusting these, the test processing using the spin coater 100 or the product processing is restarted.
[0041]
If ΔC ′ is within the standard in step 8 of FIG. 2, the step of forming a resist film on the surface of the wafer 1 is completed. In the case of performing a so-called single wafer processing in which a plurality of wafers 1 are continuously processed one by one, a resist film forming process is started from Step 1 in FIG. 2 (Steps 1 to 1 in FIG. 2). Step 10 is repeated.).
[0042]
As described above, according to the method for forming a resist film using the spin coater 100 according to the present invention, the amount of the resist solution dropped on the surface of the wafer 1 can be easily and accurately grasped. Abnormalities can be found immediately. Further, the thickness (coating thickness) of the resist film on the surface of the wafer 1 can be easily and accurately grasped.
[0043]
Therefore, since both the amount of the resist solution dropped and the thickness of the resist film can be monitored, occurrence of an abnormality in the resist film forming step can be detected with high detectability. Thereby, the quality of the resist film forming step can be improved.
In this embodiment, the resist liquid corresponds to the liquid of the present invention, and the wafer 1 corresponds to the substrate of the present invention. Further, the metal rotary stage 10 corresponds to the support base (rotary stage) of the present invention, and the metal electrode plate 20 corresponds to the electrode plate of the present invention. Further, the measuring section 40 corresponds to the measuring section of the present invention, and the spin coater 100 corresponds to the liquid applying apparatus of the present invention.
[0044]
In this embodiment, the case of a resist liquid has been described as an example of the liquid of the present invention. However, the liquid of the present invention is not limited to the resist liquid, and may be, for example, a liquid for forming an SOG.
In this embodiment, before the resist solution is dropped on the surface of the wafer 1 in step 2 of FIG. 2, the wafer 1 is placed on the turntable 10 and the turntable 10 and the electrode plate are Capacitance C between 20 and ₀ Has been described as the initial value.
[0045]
However, the dielectric constant of the wafer 1 itself and the thickness thereof are substantially constant among the plurality of wafers 1, and the initial value of the capacitance C ₀ Can be regarded as substantially constant, step 2 in FIG. 2 can be omitted.
Specifically, the initial value C ₀ Is specified in advance. Then, immediately after the maintenance of the liquid coating apparatus 100 or about once to three times a day, the initial value C is set in step 2 for only a few wafers 1. ₀ Check. Here, the initial value C ₀ Is within the range of the standard value, in the subsequent resist film forming process, the step 2 is omitted and the initial value C ₀ Is a constant value. According to such a method, the efficiency of forming the resist film can be increased.
[0046]
Further, the resist solution has a greater viscosity than water and has a property of being easily dried. For this reason, in the spin coater 100 shown in FIG. 1, as the number of processed wafers 1 increases, the tip of the discharge nozzle 30 is gradually closed by the fixed matter of the resist liquid, and the amount of the resist liquid dripped gradually decreases. Tend. This tendency is the same when the liquid for forming the SOG is dropped.
[0047]
In order to solve such a decrease in the drop amount of the resist solution, the control unit 60 shown in FIG. 1 may have a drop amount control function. For example, in step 4 of FIG. 2, the control unit 60 determines the measured value C of the capacitance measured by the measurement unit 40 while the wafer 1 on which the resist solution is dropped is placed on the rotating stage 10. ₁ To get. Here, the obtained measured value C ₁ However, when the pressure becomes lower than the target value to some extent, a control signal is sent from the control unit 60 to a pressurizing pump (not shown), and the pressure of the pressurizing container (not shown) connected to the discharge nozzle 30 is increased. Is the measured value C ₁ To some extent according to the difference between the target value and the target value.
[0048]
Thus, when the next wafer 1 is processed, the amount of the resist solution dropped on the surface of the wafer 1 can be made close to the target value. Therefore, when a plurality of wafers 1 (for example, one lot) are subjected to single-wafer processing, variations in the drop amount can be reduced within the lot. Here, the control unit 60 corresponds to the drop amount control unit of the present invention.
[0049]
Further, it is preferable that the control unit 60 shown in FIG. 1 has a speed control function of the rotary stage 10. For example, in step 7 of FIG. 2, the control unit 60 determines the measured value C of the capacitance measured by the measurement unit 40 while the wafer 1 on which the resist film is formed is placed on the rotating stage 10. ₂ To get. Here, the obtained measured value C ₂ However, if it deviates from the target value to some extent, the setting of the rotation speed and the rotation time of the rotary stage 10 stored in the data storage unit 62 is changed to the measured value C. ₂ Is changed according to the difference between the target value and the target value. The settings of both the rotation speed and the rotation time may be changed, or only one of the settings may be changed.
[0050]
Thus, when the next wafer 1 is processed, the number of rotations of the rotary stage 10 can be changed, and the thickness of the resist film formed on the surface of the wafer 1 can be made closer to the target value. Therefore, when a plurality of wafers 1 (for example, one lot) are subjected to single-wafer processing, variations in the thickness of the resist film can be reduced within the lot. Here, the control unit 60 corresponds to the rotation control unit of the present invention.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a configuration example of a spin coater 100.
FIG. 2 is a flowchart showing a process of forming a resist film.
FIG. 3 is a diagram showing a relationship between a dropping amount or a coating thickness of a resist and a capacitance.
[Explanation of symbols]
Reference Signs List 1 wafer, 10 rotation stage, 20 electrode plates, 30 discharge nozzles, 40 measurement unit, 42 voltage application unit, 44 voltmeter, 50 main unit, 60 control unit, 62 data storage unit, 64 display, 100 spin coater

Claims (10)

In a state where the substrate on which the liquid is dropped on the surface is placed on the conductive support, the support, and the electrode between the electrode plate provided on the opposite side of the support with the substrate therebetween. A liquid detection method comprising: measuring a capacitance; and calculating an amount of the liquid on a surface of the substrate based on the measured capacitance. In a state in which a substrate on which a liquid is applied to a uniform thickness on a surface is placed on a conductive support, the support and an electrode provided on the opposite side of the support with the substrate interposed therebetween. A liquid detection method, comprising: measuring a capacitance between the substrate and a substrate; and determining a coating thickness of the liquid on a surface of the substrate based on the measured capacitance. Placing the substrate on a conductive support,
Dropping a predetermined liquid on the surface of the substrate placed on the support,
In a state where the substrate on which the liquid has been dropped is placed on the support, the capacitance between the support and an electrode plate provided on the opposite side to the support with the substrate interposed therebetween Measuring the
Determining the amount of the liquid on the surface of the substrate based on the measured capacitance;
Applying the liquid dropped onto the surface of the substrate to a uniform thickness on the surface of the substrate after determining the amount of the liquid. Placing the substrate on a conductive support,
Dropping a predetermined liquid on the surface of the substrate placed on the support,
Applying the liquid to a uniform thickness on the surface of the substrate,
In a state in which the substrate on which the liquid is applied to a uniform thickness is placed on the support, the support and the electrode plate provided on the opposite side of the support with the substrate interposed therebetween. Measuring the capacitance between,
Determining a coating thickness of the liquid on the surface of the substrate based on the measured capacitance. A liquid application apparatus that applies a predetermined thickness of liquid onto the surface of the substrate by dropping a predetermined liquid on the surface of the substrate, and rotating the substrate to diffuse the liquid by centrifugal force.
A conductive rotating stage that rotatably supports the back surface of the substrate,
An electrode plate provided so as to face the rotating stage with a predetermined separation distance,
A measuring unit configured to connect one end to the rotary stage and connect the other end to the electrode plate, and measure a capacitance between the rotary stage and the electrode plate. Liquid coating device. The measurement unit is
The liquid coating according to claim 5, wherein the capacitance between the rotary stage and the electrode plate is measured while the substrate on which the liquid is dropped is placed on the rotary stage. apparatus. The measurement unit is
The capacitance between the rotary stage and the electrode plate is measured in a state where the substrate on which the liquid is applied to a uniform thickness is placed on the rotary stage. Or the liquid application device according to claim 6. The measurement unit is
In a state where the substrate is placed on the rotary stage before the liquid is dropped, the capacitance between the rotary stage and the electrode plate is measured. The liquid application device according to any one of claims 7 to 13. Acquiring the measured value of the capacitance measured by the measuring unit in a state where the substrate on which the liquid has been dropped is mounted on the rotary stage, and the drop amount of the liquid according to the acquired measured value. The liquid application device according to any one of claims 6 to 8, further comprising: a drop amount control unit configured to change the droplet amount. Acquiring the measurement value of the capacitance measured by the measurement unit in a state where the substrate on which the liquid is applied to a uniform thickness is mounted on the rotation stage, and according to the acquired measurement value. The liquid application device according to any one of claims 7 to 9, further comprising a rotation control unit configured to change a rotation speed and / or a rotation time of the rotation stage.

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