JP2004216210A - Device and method of film formation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film forming device and a method therefor for stably forming a high quality film and suppressing increase of tact time. <P>SOLUTION: An ink jet head 2 of the film forming device 10 jets a given amount of material droplets on the material application part of a substrate 7, and the thickness of the film formed on the substrate 7 by the ink jet head 2 is measured by a film thickness measuring instrument 9. An adjusting part T adjusts the amount of droplets jetted by the ink jet head 2 on the material application part of a new substrate 7 independently on the basis of the film thickness measured by the measuring instrument 9 and a prescribed film thickness. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film forming apparatus and a film forming method for forming a film on an object by an inkjet method.
Specifically, the present invention relates to a film forming apparatus and a film forming method for measuring the thickness of a formed film and using the obtained film thickness information as feedback for film formation on a new object.
[0002]
[Prior art]
For example, when an alignment film of a liquid crystal display device is formed, it is known that the film is formed by an ink-jet method for reasons such as effective use of the material of the film and prevention of adhesion of unnecessary substances such as dust. .
[0003]
In film formation by the ink jet method, it is important to uniformly control the film thickness in order to apply the material of the film as fine droplets.
In order to make the film thickness uniform, after the material droplet is sprayed on the substrate on which the alignment film is to be formed, the film thickness of the alignment film is measured. A method of applying the liquid again is known (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-9-166873
[0005]
[Problems to be solved by the invention]
However, as described in Patent Literature 1, in the method of ejecting a droplet twice to a required portion, the formed alignment film has substantially two layers.
When the alignment film has two layers, the alignment characteristics of the liquid crystal and the optical characteristics such as the refractive index of the alignment film are not uniform, and the performance as the alignment film is reduced.
Further, since the liquid droplets are ejected twice to one substrate, the tact time for manufacturing the liquid crystal display device becomes long.
[0006]
Accordingly, an object of the present invention is to provide a film forming method capable of stably forming a high-quality film and suppressing an increase in tact time.
It is another object of the present invention to provide a film forming apparatus suitable for a film forming method capable of stably forming a high-quality film and suppressing an increase in tact time.
[0007]
[Means for Solving the Problems]
A film forming apparatus according to the present invention is a film forming apparatus that forms a film by spreading of raw material droplets jetted to a plurality of positions to be jetted in a film forming surface of an object, wherein a predetermined amount of Injecting means for injecting the droplet, measuring means for measuring the thickness of the film formed on the film-forming surface by the ejecting means, based on the film thickness measured by the measuring means and a specified thickness And an adjusting means for independently adjusting the amount of the liquid droplets ejected by the ejecting means to the position to be ejected.
[0008]
Further, the film forming method according to the present invention is a film forming method in which a film is formed by spreading material droplets jetted to a plurality of jetting positions within a film forming surface of an object, wherein the jetting of the object is performed. A first ejection step of ejecting a predetermined amount of the liquid droplets to a position, a measurement step of measuring a thickness of a film formed on the film formation surface by the first ejection step, and measurement in the measurement step. An adjusting step of independently adjusting the amount of the droplet to be ejected to the ejection position based on the film thickness and a prescribed thickness, and adjusting the amount of the droplet to be ejected to a new object. And a second injection step of injecting the liquid at a position.
[0009]
In the present invention, the ejecting unit independently ejects a predetermined amount of film droplets of the film for each of the positions to be ejected to a plurality of positions to be ejected within the film forming surface of the object. A film is formed on the film formation surface of the target object by spreading the droplets ejected on the film formation surface by the ejection means.
The thickness of the film formed on the film formation surface of the object is measured by the measuring means.
The adjusting unit adjusts the amount of the droplet to be ejected to the position to be ejected based on the difference between the actual film thickness measured by the measuring unit and the specified film thickness at a predetermined position to be ejected on the film forming surface. Independently adjusted for each injection position.
The droplets of the amount adjusted by the adjusting means are ejected by the ejecting means to the film-forming surface of a new object for each ejected position.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the following, embodiments of the present invention will be described using a liquid crystal display device in which an alignment film is formed by an inkjet method as an example.
[0011]
FIG. 1 shows a schematic configuration of a film forming apparatus according to an embodiment of the present invention.
The film forming apparatus 10 shown in FIG. 1 includes a computer 1, an inkjet head 2, a film thickness measuring device 9, an ejection stage 4, a measurement stage 40, an ejection controller K1, and a measurement controller K2. . The computer 1 further has a control unit C, an adjustment unit T, and a storage unit M.
The ink jet head (hereinafter, abbreviated as head) 2, the ejection stage 4, and the ejection controller K1 correspond to an embodiment of an ejection unit in the present invention.
The film thickness measuring device 9, the measuring stage 40, and the measuring controller K2 correspond to one embodiment of the measuring means in the present invention.
Further, the adjusting unit T corresponds to an embodiment of the adjusting unit in the present invention.
[0012]
In the film forming apparatus 10, the thickness of a film formed by ejecting droplets onto the substrate 7 in the ejection stage 4 can be measured in the measurement stage 40. The information of the film thickness measured in the measurement stage 40 is fed back, and the amount of the droplet ejected to the new substrate 7 in the ejection stage 4 is adjusted.
[0013]
The injection stage 4 includes a table moving mechanism using, for example, a ball screw, and a substrate 7 as an object on which an alignment film is to be formed is placed on the table. When the table is moved by the moving mechanism, the substrate 7 moves within the XY plane.
The head 2 is arranged so as to face the alignment film formation surface of the substrate 7.
[0014]
FIG. 2 is a diagram showing a schematic configuration of the head 2. As shown in FIG. 2, the head 2 is preferably an ink jet that ejects a raw material liquid for an alignment film as droplets from minute ejection holes provided in a plurality of nozzles 20 arranged at a predetermined pitch in one direction. It is a system of injection means. In the present embodiment, a piezo-type inkjet head is preferably used.
The head 2 sprays a liquid droplet of an alignment film on the film-forming surface of the substrate 7 disposed at a position facing the head.
FIG. 2 shows the head 2 having four nozzles 20 as an example for description, but the number of nozzles 20 can be changed as appropriate. In actual film formation, for example, a head having 2500 nozzles 20 is used. Further, a head having a plurality of nozzle rows in which a plurality of nozzles 20 are arranged in one direction may be used.
[0015]
As shown in FIG. 2, the head 2 is connected to the ejection controller K1, and receives a command signal from the ejection controller K1 to eject droplets from the nozzle 20.
Since it is necessary to pattern the alignment film into a predetermined shape, the output timing of the ejection control command signal such as the ejection start signal and the stop signal from the ejection controller K1 is independent for each nozzle 20 in the related art. Was controlled. However, drive waveforms such as the pulse width, pulse number, and inclination of the command signal have been common to all nozzles 20 in the past.
On the other hand, in the present embodiment, as shown in FIG. 2 as an example, the ejection control command signals DN1 to DN4 output from the injection controller K1 to the four nozzles 20 are not only output timings but also drive waveforms. Can be independently adjusted for each of the signals DN1 to DN4.
Thus, the amounts of the droplets Dp1 to Dp4 ejected from each nozzle 20 can be controlled independently.
[0016]
The control of the droplet amount for each nozzle 20 will be described in more detail with reference to FIG.
As illustrated in FIG. 3, the nozzle 20 of the piezo-type inkjet head 2 includes a piezo element 22 in an ejection pipe 21.
An alignment film liquid is supplied from an alignment film supply device (not shown) to the cavity 23 inside the injection pipe 21 in accordance with the displacement of the piezo element 22.
Note that the alignment film liquid is a liquid in which the raw material of the alignment film is adjusted to a predetermined concentration. As a raw material of the alignment film, for example, an organic polymer material such as polyimide is used.
[0017]
When a voltage is applied to the piezo element 22 in response to a command signal from the injection controller K1, the piezo element 22 is displaced. FIG. 3A illustrates a case where the piezo element 22 extends in the vertical direction.
As shown in FIG. 3A, the ejection tube 21 is pressed and deformed by the displacement of the piezo element 22, and the alignment film liquid is discharged as a droplet from the ejection hole 21 a of the ejection tube 21.
[0018]
The size of the ejected droplet, that is, the amount of the droplet is determined by the shape and size of the ejection hole 21a, the shape and capacity of the cavity 23, the shape and displacement of the piezo element 22, and the waveform of the drive voltage applied to the piezo element 22. And so on. Therefore, as shown below, as an example, the droplet amount changes due to the difference in the waveform of the drive voltage.
[0019]
As shown in FIG. 3A, a single pulse S having one pulse is applied to the piezo element 22 of the nozzle 20 as a drive voltage. At this time, the piezo element 22 is displaced so that the alignment film liquid corresponding to the area SA of the pulse S is sucked into the cavity 23 and discharged, and the droplet Dp1 in an amount based on the area SA is discharged from the nozzle 20. .
When ejecting a droplet having a smaller volume than the droplet Dp1, for example, a double pulse W having two pulses as shown in FIG. 3B is applied to the piezo element 22.
When the first pulse W1 of the pulses W is given, the piezo element 22 is displaced so that the alignment film liquid corresponding to the area W1A is sucked into the cavity 23 and discharged. The piezo element 22 is displaced by the second pulse W2 given after the state in which the alignment film liquid is discharged, so that the droplet is pulled back from the ejection hole 21a into the cavity 23. By adding the pull-back operation, it is possible to discharge a small droplet Dp2 having a smaller amount than the droplet Dp1, even if the ejection holes 21a have the same shape and size.
[0020]
As described above, by changing the drive voltage waveform applied to the piezo element 22, in the present embodiment, the same nozzle 20 can realize droplets having a difference of about twice the amount (for example, 240 ng versus 110 ng). Can be.
By changing the capacity of the cavity 23, the shape of the piezo element 22, and the amount of displacement, it is possible to realize a larger difference.
As described above, in the present embodiment, by changing the pulse width and the drive voltage value of the drive voltage waveform via the ejection controller K1, the amount of the ejected droplets can be controlled independently for each nozzle 20. It is possible.
By adjusting the rise and fall times of the drive waveform, the ejection amount can be more finely adjusted for each nozzle 20.
[0021]
The ejection controller K1 is connected to the head 2 and the ejection stage 4.
The injection controller K1 outputs a movement command signal MC1 for giving an instruction such as a movement amount, a movement direction, and a movement timing of the table to the ejection stage 4 based on the command signal DS1 from the computer 1. The ejection stage 4 moves the table on which the substrate 7 is placed on the XY plane based on a movement command signal MC1 from the ejection controller K1.
In this embodiment, the head 2 is fixed, and the substrate 7 on the ejection stage 4 is moved in a plane. However, the substrate 7 is fixed and the head 2 is moved in a plane. It may be. It is also possible to adopt a mode in which both the head 2 and the substrate 7 are moved.
[0022]
The measurement stage 40 has the same structure as the ejection stage 4, and the substrate 7 on which the alignment film is formed on the ejection stage 4 is placed on a table provided with a moving mechanism.
Although not shown, a transfer means such as a belt conveyor or a robot arm can be used to move the substrate 7 from the injection stage 4 to the measurement stage 40.
[0023]
The film thickness measuring device 9 is arranged so as to face the substrate 7 on the measuring stage 40.
As the film thickness measuring device 9, any measuring means can be used as long as the film thickness of the alignment film formed on the film forming surface of the substrate 7 can be measured.
In the present embodiment, as an example, a light interference type film thickness measuring device is used.
[0024]
The optical interference type film thickness measuring device 9 emits the measurement light LT to the substrate 7 on which the alignment film is formed, and the measurement light LT emits the measurement light LT between the surface of the alignment film and the alignment film and the film formation surface. Information on the thickness of the alignment film is obtained by utilizing interference of reflected light generated by reflection at the interface.
As an example, the measurement light LT is incident on the film formation surface and the alignment film at an appropriate angle. The reflected light of the measurement light LT incident on the substrate 7 on which the alignment film is formed includes the reflected light RL1 reflected on the alignment film surface due to the thickness of the alignment film and the interface between the alignment film and the film formation surface. An optical path difference occurs with the reflected light RL2 reflected by the light source.
[0025]
Due to the optical path difference, the reflected light RL1 and the reflected light RL2 received by the film thickness measuring device 9 cause interference, and the intensity of the reflected light as a whole changes as compared with the intensity of the measurement light LT.
Assuming that the wavelength λ of the measurement light LT is constant, the intensity of the reflected light depends on the thickness of the alignment film. Therefore, if the relationship between the film thickness and the light intensity corresponding to the wavelength λ is obtained in advance, the film thickness of the alignment film can be obtained.
[0026]
The film thickness measuring device 9 and the measuring stage 40 are respectively connected to the output side of the measuring controller K2.
The measurement controller K2 generates a movement command signal MC2 for giving an instruction such as a movement amount, a movement direction, and a movement timing of the table based on a command signal DS2 from the computer 1 input to the input side. The measurement controller K2 outputs the generated movement command signal MC2 to the measurement stage 40. The measurement stage 40 moves the table on which the substrate 7 is placed on the XY plane based on a movement command signal MC2 from the measurement controller K2.
While moving the table of the measurement stage 40, the measurement controller K2 outputs a measurement command signal SC for causing the film thickness measuring device 9 to measure the film thickness of the alignment film.
This makes it possible to measure the film thickness at any position on the alignment film. The obtained measurement data DT of the film thickness is transmitted to the computer 1.
[0027]
In the present embodiment, the film thickness measuring device 9 is also fixed to the measurement stage 40, and the substrate 7 on the measurement stage 40 is moved in a plane. However, similarly to the injection stage 4, the substrate 7 may be fixed and the film thickness measuring device 9 may be moved along the film formation surface of the substrate 7, or both the substrate 7 and the film thickness measuring device 9 may be moved. It is also possible to take the form.
[0028]
The control unit C of the computer 1 is realized by, for example, a CPU (Central Processing Unit). The control unit C is connected to the storage unit M and the adjustment unit T.
The control unit C receives the measurement data DT from the film thickness measuring device 9 and transmits it to the storage unit M. The storage unit M stores the measurement data DT from the control unit C.
Further, the control section C outputs a command signal DS2 to the measurement controller K2 to measure the film thickness at a predetermined position of the alignment film formed on the film formation surface of the substrate 7.
Further, the control unit C transmits the obtained measurement data DT to the adjustment unit T, and adjusts the amount of the droplet ejected by the head 2.
Hereinafter, the configurations of the storage unit M and the adjustment unit T will be described in detail.
[0029]
FIG. 4 is a functional configuration block diagram of the storage unit M and the adjustment unit T of the computer 1.
The storage unit M is configured by appropriately using storage means such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a hard disk drive.
The adjustment unit T is realized by a CPU, as in the control unit C, for example.
[0030]
As illustrated in FIG. 4, the storage unit M includes a reference droplet amount storage unit Dref, a reference film thickness storage unit mref, and a measurement data storage unit SDP.
The reference droplet amount storage unit Dref stores a reference amount of a droplet for obtaining an alignment film having a target film thickness. As will be described later, this reference droplet amount ref2 is defined in advance for each position to be ejected on the deposition surface of the substrate 7. Therefore, the reference droplet amount storage unit Dref stores a number of reference droplet amounts ref2 corresponding to the positions to be ejected on the film formation surface, and the value of the reference droplet amount ref2 is adjusted by the adjustment unit as necessary. T.
[0031]
The appropriate amount of the reference liquid ref2 is, for example, a predetermined thickness and a predetermined uniformity obtained by measuring the film thickness of the alignment film formed by actually ejecting the droplet onto the substrate 7 using the head 2. The injection conditions can be obtained by setting conditions experimentally obtained.
[0032]
The reference film thickness storage unit mref stores a target reference film thickness ref1 of the alignment film to be actually formed.
In some cases, components for display, such as electrodes and color filters, are formed on the substrate 7. In this case, in order to form an alignment film having a flat surface, the thickness of the alignment film depends on the position to be sprayed on the film formation surface, such as the film thickness on the above components and the film thickness in other regions. Different thickness.
In such a case, as with the reference droplet amount ref2, the reference film thickness ref1 is stored in the reference film thickness storage unit mref in a number corresponding to the position to be ejected.
Further, the value of the reference film thickness ref1 is also supplied to the adjustment unit T as needed.
[0033]
The measurement data storage unit SDP is connected to the control unit C as shown in FIGS. The measurement data DT from the film thickness measuring device 9 connected to the connection portion CP1 is input to the measurement data storage portion SDP via the control portion C. The measurement data storage unit SDP stores the measurement data DT.
The measurement data storage unit SDP constructs a measurement data database by storing the input measurement data DT. If necessary, the past measurement data DTP is provided from this database to a filter unit of the adjustment unit T described later.
[0034]
As illustrated in FIG. 4, the adjustment unit T includes, for example, a filter unit 50, operation units CL1 and CL2, a droplet amount calculation unit DCAL, and a voltage conversion unit VCAL.
The control unit C is connected to the filter unit 50, and measurement data DT measured by the film thickness measuring device 9 is input to the filter unit 50.
As will be described in detail later, when the input film thickness measurement data DT is within a predetermined range, the filter unit 50 outputs the measurement data DT as it is. The filtering for outputting the substitute data instead of the measurement data DT is executed. Hereinafter, data output from the filtering unit 50 as a result of the filtering is referred to as filtering data DTF.
As will be described later, the filter unit 50 calculates the substitute data using the past measurement data DTP stored in the measurement data storage unit SDP.
[0035]
The calculation unit CL1 is connected to the filter unit 50 and the reference film thickness storage unit mref.
The calculation unit CL1 calculates the difference between the reference film thickness ref1 input from the reference film thickness storage unit mref and the filtering data DTF input from the filter unit 50, and calculates a film thickness difference e.
The film thickness difference e calculated by the calculation unit CL1 is output to the droplet amount calculation unit DCAL.
[0036]
Based on the film thickness difference e input from the calculation unit CL1, the liquid appropriate amount calculation unit DCAL calculates a droplet amount ad corresponding to the film thickness difference e.
The relationship between the film thickness and the amount of liquid droplets depends on the film formation pattern of the alignment film, how the droplets adhered to the film formation surface are spread by leveling, the difference between the lots of the alignment film liquid, temperature, humidity, etc. It is not easy to state briefly because the conditions are complicated. Therefore, a method for calculating the droplet amount ad based on the film thickness difference e is not described here. However, in consideration of the film forming conditions, the droplet amount ad corresponding to the film thickness difference e is calculated with a certain degree of accuracy. It is possible to ask.
[0037]
The calculation unit CL2 is connected to the output destination of the droplet amount calculation unit DCAL, and the value of the appropriate liquid amount ad calculated by the droplet amount calculation unit DCAL is input to the calculation unit CL2.
The calculation unit CL2 is also connected to the reference droplet amount storage unit Dref, and the reference droplet amount ref2 stored in the reference droplet amount storage unit Dref is also input to the calculation unit CL2.
The calculation unit CL2 calculates the difference between the reference liquid appropriate amount ref2 and the droplet amount ad to calculate the droplet amount difference ae. The existence of the droplet amount difference ae means that there is an error between the amount of droplets actually ejected from each nozzle 20 and adhering to the film formation surface and the predetermined reference droplet amount ref2. Means that you were. Therefore, it is necessary to correct this error in order to control the film thickness with high accuracy.
The droplet amount difference ae calculated by the calculation unit CL2 is output to the voltage conversion unit VCAL.
[0038]
The voltage conversion unit VCAL determines the driving voltage of the nozzle 20 and its waveform, which define the amount of the droplet ejected from the head 2, based on the droplet amount difference ae.
FIG. 5 is a graph showing a relationship between the driving voltage of the nozzle 20 and the ejection amount of the droplet from the nozzle 20.
In the graph of FIG. 5, the horizontal axis represents the drive voltage Vh [V], and the vertical axis represents the discharge amount Iw [ng].
As shown in FIG. 5, there is a certain relationship between the ejection amount Iw and the driving voltage Vh. For example, according to the graph of FIG. 5, the ejection amount Iw and the driving voltage Vh have a substantially linear relationship. A liquid for correcting the droplet amount difference ae based on the droplet amount difference ae using the relationship between the ejection amount Iw and the driving voltage Vh and the relationship between the driving waveform and the ejection amount shown in FIG. The amount of the droplet can be converted into a drive voltage Vh for discharging this amount of the droplet.
[0039]
The voltage conversion unit VCAL outputs a command signal DS1 including a drive voltage Vh for discharging a droplet of an amount adjusted to a specified film thickness to the ejection controller K1 via the connection unit CP2.
With the above configuration, the amount of the liquid droplet ejected from the head 2 can be adjusted based on the measurement data of the film thickness measured by the film thickness measuring device 9.
[0040]
Hereinafter, an operation of forming an alignment film on the substrate 7 while feeding back the measurement data DT using the above-described film forming apparatus 10 will be described with reference to a flowchart shown in FIG.
In the case of forming a film on the substrate 7, first, conditions are determined as described above, and a driving voltage of the nozzle 20 which has a predetermined film thickness and uniformity, an appropriate amount of the reference liquid ref2 derived from the driving voltage, and the like. Obtain the injection conditions.
The obtained injection conditions are stored in the storage unit M as described above.
[0041]
In the manufacture of the substrate 7 with an alignment film as a product, first, under predetermined injection conditions, droplets of the alignment film are ejected by the head 2 onto the film-forming surface of the substrate 7 placed on the ejection stage 4. (Step ST1).
When forming a film on the first substrate 7, droplets are ejected based on the normative ejection conditions stored in the storage unit M obtained by setting the conditions.
At this time, as shown in FIG. 7A, the droplet Dp2 is disposed between the circular droplets Dp1 having the diameter rd1 which adhere to the film forming surface of the substrate 7 at a predetermined pitch, and the diameter is smaller than the diameter rd1. The head 2 and the ejection stage are driven so as to have a circular shape of rd2.
[0042]
The droplets Dp2 are arranged so as to fill the droplets Dp1 in a region where the distance between the droplets Dp1 attached to the film formation surface is the longest. That is, the normative ejection condition is a condition under which the droplet from the nozzle 20 of the head 2 adheres as shown in FIG.
The injection conditions under which the film thickness becomes a desired value and becomes uniform over the entire surface of the film formation surface differ depending on the position to be sprayed on the film formation surface. The uniform droplets Dp1 and Dp2 may be arranged as shown in FIG. While relatively moving the head 2 and the substrate 7 on the ejection stage 4, droplets are ejected from the head 2 so as to be arranged as shown in FIG. It is possible to obtain an alignment film having a uniform thickness and thinner than the conventional alignment film.
[0043]
In the present embodiment, the ejection condition deviates from the ideal condition due to a partial ejection failure of the plurality of nozzles 20 or a difference in the ejection condition such as a difference in the alignment film liquid for each lot. In order to prevent the sizes of the droplets Dp1 and Dp2 from being varied as shown in FIG.
[0044]
For this purpose, in the present embodiment, the substrate 7 on which the alignment film is formed on the injection stage 4 is transferred to the measurement stage 40, and the thickness of the alignment film is measured by the film thickness measuring device 9 on the measurement stage 40 (step ST2). ).
FIG. 8 is a plan view of the substrate 7 showing an example of measurement points in the film thickness measurement.
The greater the number of measurement points, the closer to the actual condition, the more accurate the evaluation of the film thickness uniformity of the formed alignment film becomes. However, there is a trade-off with the tact time, and the number of measurement points cannot be increased much. In the present embodiment, as an example, as shown in FIG. 8, fifteen measurement points corresponding to the positions to be ejected on the film formation surface Su of the substrate 7 from the measurement point PT1 to the measurement point PT15 are defined in a mesh shape. .
[0045]
In the present embodiment, it is assumed that the film thickness measuring device 9 can measure only one point at a time, and sequentially measures from the measurement point PT1 to the measurement point PT15 along the direction of the arrow shown in FIG. . However, for example, when a film thickness measuring device in which three film thickness measuring devices 9 are arranged in the X direction in FIG. 8 is used, only the relative movement of the film thickness measuring device and the substrate 7 in the Y direction is sufficient. The film thickness at the measurement point can be measured.
[0046]
Based on the measurement data at the measurement points PT1 to PT15, the data of the film thickness at the injection positions other than the measurement points PT1 to PT15 is complemented in both the X direction and the Y direction by a complementary method such as the least square method. Can be.
The complement of this data is performed, for example, in the control unit C of the computer 1. The complementary data between the measurement points calculated by the control unit C is also stored in, for example, the measurement data storage unit SDP.
[0047]
When the formation of the alignment film and the measurement of the film thickness are continued for each substrate 7, a graph showing the relationship between the number of substrates and the film thickness at each measurement point is obtained as shown in FIG. In the graph shown in FIG. 9, the horizontal axis indicates the number of the measured substrates 7 [sheets], and the vertical axis indicates the film thickness [nm] at each speed fixed point.
As shown in FIG. 8, 15 plots can be obtained when 15 points are measured, and more plots can be obtained if supplemented data is included. However, in the graph of FIG. 9, only two plots, a plot PL1 shown by a solid line and a plot PL2 shown by a broken line, are shown for simplification of display.
[0048]
When the film thickness is measured, the filter unit 50, including the complemented data, determines whether or not the input measurement data DT is within a predetermined specified range as indicated by a dotted line FL in the graph of FIG. A decision is made (step ST3).
If all values of the measurement data DT are within the specified range, the filter unit 50 outputs the input measurement data DT as it is to the calculation unit CL1 as the filtering data DTF.
[0049]
If a value outside the specified range exists in the input measurement data DT, the filter unit 50 outputs substitute data as filtering data DTF instead of the data outside the specified range.
As an example, it is assumed that a plot PL1 of the graph of FIG. 9 indicates measurement data at the measurement point PT5 illustrated in FIG. The plot PL1 in FIG. 9 indicates that the film thickness at the measurement point PT5 of the seventeenth substrate 7 was out of the specified range. Note that, in the following, the injection target position at which the measurement data or the complementary data outside the specified range is detected is referred to as an unspecified injection target position.
When the input measurement data is out of the specified range, the filter unit 50 generates the substitute data ADT1 and uses it instead of the data outside the specified range (step ST4).
[0050]
There are various methods for calculating the substitute data ADT1. For example, the measurement data at the measurement point PT5 of the 16th previous substrate 7 stored in the measurement data storage unit SDP is directly used as the substitute data ADT1. Instead of the previous data, the average value of the measurement data of the measurement points PT5 over the past several sheets may be used as the substitute data ADT1.
Alternatively, the substitute data ADT1 is calculated using the measurement points around the measurement point PT5 such that the average value of the measurement data of the measurement points PT2, PT4, PT6, and PT8 of the same seventeenth substrate 7 is calculated. You may. Also in the case of using the data of the measurement points around the prescribed outside injection position, the past measurement data of the measurement points around the prescribed outside injection position instead of the same substrate may be used.
[0051]
When calculating the substitute data using the past measured data, it is preferable not to use the measured data that is out of the specified range from the viewpoint of improving the accuracy of the calculated substitute data. For example, as shown in FIG. 9, when calculating the substitute data ADT2 of the measurement point PT5 on the 41st substrate 7 which is out of the specified range, the measurement data of the measurement point PT5 on the 17th substrate 7 Is not used.
In addition, the description has been given so far on the measurement points defined in advance. However, alternative data can also be generated for the specified jacket injection position between specified measurement points. In this case, the substitute data can be generated using the measurement data of the specified measurement point, or the substitution data can be generated using the complementary data obtained by complementing the measurement data of the measurement point.
Also in the case of calculating the above-mentioned alternative data of the specified measurement point, supplementary data at the injection position other than the measurement point may be used.
[0052]
As described above, based on the filtering data DTF that changes as appropriate depending on whether or not there is data outside the specified range, the liquid amount calculation unit DCAL and the calculation unit CL2 determine the droplet amount for setting the reference film thickness ref1. The difference ae is obtained (step ST5).
The droplet amount difference ae is calculated at least for specified measurement points such as the measurement points PT1 to PT15. It can also be calculated for each position.
[0053]
If the droplet amount difference ae is determined so that the value of the filtering data DTF is compensated by 100%, the feedback system may diverge if a disturbance is applied to the feedback system. For this reason, a feedback coefficient such as a gain when obtaining the droplet amount difference ae is suitably determined appropriately in consideration of the stability of the feedback system.
[0054]
Based on the droplet amount difference ae calculated by the appropriate liquid amount calculation unit DCAL and the calculation unit CL2 and the reference liquid droplet amount ref2, the voltage conversion unit VCAL determines the amount of liquid droplets to be ejected by the head 2 by the reference liquid appropriate amount ref2. Is generated (step ST6).
This command signal DS can also be calculated for each ejection target position based on the relative positional relationship between the film formation surface of the substrate 7 and each nozzle 20 of the head 2, and can be given to each nozzle 20 independently.
[0055]
After the measurement of the film pressure of the substrate 7 is completed, it is determined whether a new film is formed on the substrate 7 (step ST7).
For example, when the production of one lot of the substrate 7 is completed, no new substrate is prepared, and the film formation of the substrate 7 is completed.
When the film formation of the substrate 7 is continued, a new substrate 7 is prepared on the ejection stage 4 (step ST8).
In the present embodiment, when the command signal DS1 is generated, a new substrate 7 on which an alignment film is to be formed is prepared on the ejection stage 4.
However, if the injection is performed based on the control command DS1 obtained in steps up to step ST6, a new substrate 7 can be prepared in any of steps ST2 to ST6.
In addition, as shown in FIG. 1, in a configuration in which the ejection stage 4 and the measurement stage 40 have different configurations, in order to shorten the tact time, the ejection stage 4 is used even during the measurement of the film thickness in the measurement stage 40. It is preferable that an alignment film is formed on another substrate 7. In this case, the measurement data of the substrate 7 measured on the measurement stage 40 is reflected on the film formation on the substrate 7 after two substrates.
If the injection is performed after the command signal DS1 is generated unless the shortening of the tact time is considered, the data of the substrate 7 used for the measurement can be reflected in the injection of the next substrate 7. .
[0056]
After a new substrate 7 is prepared on the ejection stage 4 in step ST8, the process returns to step ST1 to form an alignment film on the prepared substrate 7. At this time, by independently driving each of the nozzles 20 of the head 2 using the control command DS1 obtained up to step ST6, the droplet whose amount is adjusted to have a desired film thickness is ejected. Injected for each position.
Hereinafter, the loop from step ST1 to step ST8 is repeated until the film formation on the substrate 7 is completed.
[0057]
As described above, the amount of droplets to be ejected to the film formation surface of the substrate 7 is adjusted for each position to be ejected on the film formation surface so as to have a desired film thickness.
Therefore, according to the present embodiment, it is possible to continuously obtain a substrate on which a high-quality film having a film thickness close to a specified value and high in-plane uniformity of the film thickness is formed. The quality of the obtained film is high because droplets of which the amount is adjusted are formed by spraying the droplets only once at the position to be sprayed on the film formation surface.
Further, since it is possible to cope with the variation of the injection condition for each lot, the number of times of setting the injection condition can be reduced, and an increase in the tact time can be suppressed because the film is formed by one injection.
The fact that the number of times of setting the conditions is small and the need for repeated ejection on one substrate is not required is also effective in reducing the number of raw material droplets of the film.
Further, since the film thickness is measured, it becomes easy to notice the occurrence of manufacturing defects. It is also useful for shortening the time for investigating and eliminating the cause of manufacturing defects.
[0058]
When a filter unit that determines whether or not the measured data of the film thickness is out of the specified range is used, it is possible to execute a process such as issuing a warning when detecting the measured data out of the specified range. As a result, an increase in manufacturing defects can be prevented.
Since measurement data outside the specified range is not used, it is also effective for stabilizing the feedback system.
Further, even when measurement data out of the specified range is detected, it is possible to continuously and stably form a high-quality film by using the substitute data.
[0059]
Deformation form
In the film forming apparatus 10 shown in FIG. 1, the injection stage 4 and the measurement stage 40 have different configurations, but both may be integrated.
FIG. 10 is a view showing a schematic configuration of a film forming apparatus according to a modified embodiment of the present invention, which performs droplet ejection and film thickness measurement in one stage.
[0060]
In the film forming apparatus 100 shown in FIG. 10, the head 2 and the film thickness measuring device 9 are arranged integrally or at positions close to each other.
Further, instead of the measurement controller K2, the film thickness measuring device 9 according to the modified embodiment has a measurement controller for measuring the film thickness at a predetermined position to be ejected in cooperation with the movement of the substrate 7 on the ejection stage 4. K3 is connected.
With this configuration, in the present modification, it is possible to simultaneously form an alignment film and measure the thickness of the substrate 7 on the ejection stage 4.
The other configurations and functions are the same as those in the above-described embodiment, and thus detailed description is omitted.
[0061]
According to the present modification, the tact time of film formation on the substrate 7 can be further reduced.
Further, if the film thickness distribution on the film formation surface is estimated from the measurement result of the film thickness during the formation, it is possible to prevent a change in the film thickness on the substrate 7 during the film formation.
[0062]
Although the embodiments of the present invention have been described above, the descriptions of the configurations, shapes, numerical values, and the like in the above embodiments are examples for describing the present invention, and the present invention is not limited to the above embodiments.
For example, the condition for issuing a warning can be set as appropriate. For example, when the measurement data outside the specified range is repeated a plurality of times, or when the measurement data outside the specified range is concentrated near a specific injection target position, for example, the value of the droplet amount as a result of performing the feedback increases. A warning can be issued if it continues or decreases. Also, as a result of executing the feedback, a warning can be issued, for example, when the value of the appropriate amount of liquid repeatedly increases and decreases and the feedback system does not converge, and as a result, the uniformity of the film thickness decreases.
Further, the present invention can be applied not only to the production of an alignment film but also to the production of any film using an inkjet method. Depending on the type of the liquid droplets to be ejected, it is also possible to use a thermal inkjet head that ejects the droplets by thermal expansion of the liquid material instead of the piezo method.
[0063]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a film forming method capable of stably forming a high-quality film and suppressing an increase in tact time.
In addition, a film formation apparatus suitable for a film formation method capable of stably forming a high-quality film and suppressing an increase in tact time can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a schematic configuration of the ink jet head illustrated in FIG. 1;
3A is an example of a droplet discharge state by a nozzle of the inkjet head illustrated in FIG. 2, and FIG. 3B is another example of a discharge state.
FIG. 4 is a functional configuration block diagram of a storage unit and an adjustment unit illustrated in FIG. 1;
FIG. 5 is a graph showing a relationship between a driving voltage of a nozzle of the illustrated ink jet head and a discharge amount of a droplet from the nozzle.
FIG. 6 is a flowchart illustrating a film forming method according to an embodiment of the present invention.
FIG. 7A is a diagram illustrating an example of a pattern of a liquid droplet adhering to a film forming surface of a substrate by the film forming apparatus illustrated in FIG. 1, and FIG. It is a figure showing a changed state.
FIG. 8 is a plan view of the substrate, showing measurement points in film thickness measurement.
FIG. 9 is a graph showing the relationship between the number of substrates on which a film is formed and the film thickness at each measurement point of the substrate.
FIG. 10 is a schematic configuration diagram of a film forming apparatus according to a modification of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Computer, 2 ... Ink jet head, 4 ... Injection stage, 7 ... Substrate, 9 ... Thickness measuring device, 40 ... Measurement stage, 50 ... Filter part, K1 ... Injection controller, K2 ... Measurement controller, C ... Control part, T: adjustment unit, M: storage unit

Claims (6)

A film forming apparatus for forming a film by spreading of raw material droplets jetted to a plurality of positions to be jetted in a film forming surface of an object,
Ejecting means for ejecting a predetermined amount of the droplets to the ejected position,
Measuring means for measuring the thickness of the film formed on the film forming surface by the injection means,
A film forming apparatus comprising: an adjusting unit that independently adjusts an amount of the droplet ejected to the ejection target position by the ejecting unit based on the film thickness measured by the measuring unit and a prescribed thickness. The adjusting unit is configured such that the film thickness within the specified range measured in the past at the specified externally ejected position with respect to the specified externally ejected position where the film thickness measured by the measuring unit is out of the predetermined specified range. The film forming apparatus according to claim 1, wherein an amount of the droplet ejected to the prescribed outer ejection position is adjusted based on a thickness. The adjusting unit is configured such that a film thickness measured by the measuring unit is out of a predetermined specified range, and a film measured at the target position around the specified specified position. The film forming apparatus according to claim 1, wherein an amount of the liquid droplet ejected to the prescribed outer ejection position is adjusted based on a thickness. A film forming method for forming a film by spreading material droplets ejected to a plurality of positions to be ejected within a film forming surface of an object,
A first ejection step of ejecting a predetermined amount of the droplet to the ejection position of the target;
A measuring step of measuring a thickness of a film formed on the film forming surface by the first spraying step;
An adjusting step of independently adjusting the amount of the droplet ejected to the ejected position based on the thickness and the specified thickness measured in the measuring step,
A second jetting step of jetting the adjusted amount of the droplets to the target position of a new target. In the adjusting step, the film thickness measured in the measuring step is outside the predetermined specified range, the specified outer coating position, the film thickness in the specified range previously measured at the specified outer coating position. The film forming method according to claim 4, wherein an amount of the liquid droplet ejected to the prescribed external ejection position is adjusted based on the amount. In the adjusting step, the film thickness measured in the measuring step is outside the predetermined specified range, the specified outer injection position, the film thickness measured at the injection position around the specified outer injection position The film forming method according to claim 4, wherein the amount of the liquid droplet ejected to the specified external ejection position is adjusted based on the predetermined amount.

Images