JP2009208044A - Method for forming thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the deviation in the amount of discharge in a method for forming a thin film. <P>SOLUTION: The method for forming a thin film by discharging liquid bodies onto a substrate to be treated while relatively scanning the substrate to be treated and a liquid drop discharge head equipped with a plurality of discharge units discharging the liquid bodies includes an inspection process of inspecting the respective amounts of the liquid bodies discharged to a substrate to be inspected by driving two or more of discharge units with a predetermined signal, an adjusting process of adjusting the predetermined signal based on the inspection result, and a thin-film forming process of forming a thin film by arranging the liquid bodies on the substrate to be treated not only by using the adjusted driving signal, but by selectively operating of the plurality of the discharge units for discharge and differentiating the respective scanned discharging patterns of the selected discharge units. The inspection process includes an arrange treatment selecting two or more of the discharging patterns different in the thin-film forming process and arranging the liquid bodies on the substrate to be inspected based on the discharging patterns. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin film forming method.

  In recent years, a film forming technique using a droplet discharge method has attracted attention. According to the droplet discharge method, it is possible to dispose a minute liquid containing a film forming material at a desired position. Thereby, a fine film pattern can be formed, and patterning is facilitated as compared with the case of using a photolithography method. In addition, since the waste of the film forming material can be reduced, the manufacturing cost can be reduced.

  A droplet discharge head used in the droplet discharge method includes, for example, a large number of discharge units arranged in the Y direction. Each discharge unit includes a liquid reservoir, a nozzle, a piezoelectric element that pressurizes the liquid and pushes it out of the nozzle. In order to dispose the liquid material, the liquid material is discharged from the discharge unit while scanning the application region in the X direction with the droplet discharge head. The liquid can be arranged with the width of the droplet discharge head by one scan.

  In addition, by performing a plurality of scans with different relative positions in the Y direction between the application region and the droplet discharge head, the liquid material can be disposed over the entire application region wider than the width of the droplet discharge head. . The operation of performing one application over the entire application region may be referred to as a pass. Usually, a predetermined amount of liquid material is arranged by performing a plurality of passes.

  In the droplet discharge head, it is important to make the discharge amount of the liquid material uniform in the plurality of discharge units. This is because if the discharge amount varies, the film thickness varies in the Y direction. For example, when a film thickness variation occurs in the color filter of the image display device, this is recognized as a streak (straight line) along the X direction, and the display quality is impaired.

In order to reduce the variation in the discharge amount, it is conceivable to apply the methods disclosed in Patent Documents 1 and 2. In Patent Document 1, the discharge operation of a discharge unit in which the discharge amount of droplets is significantly different from a set value is regulated to reduce the variation in discharge amount. Further, in Patent Document 2, in an ink jet recording head (printer), the size (ejection amount) of recording dots is made variable by selecting a plurality of types of actuator drive voltage waveforms. In applying these techniques, it is extremely important to know the discharge amount of each discharge unit accurately. This is because knowing how much the discharge amount differs from the set value makes it possible to control the discharge amount satisfactorily.
JP 2003-159787 A JP-A-9-17483

  In general, the evaluation of the discharge amount is performed by driving all the discharge units at a constant voltage value, placing the liquid material on the substrate, and measuring the volume of the disposed liquid material. However, the discharge amount evaluated in this way may be different from the discharge amount in the actual film forming process for the following reason.

  When a film is formed on a large substrate such as a large device substrate or a multi-surface substrate, the liquid material is arranged by a plurality of scans or a plurality of passes. This is because an increase in the size of the droplet discharge head causes problems such as an increase in apparatus cost and an increase in the number of discharge units resulting in a large variation in characteristics.

  When performing a plurality of scans, the combination of ejection units used for each scan differs depending on the drawing pattern. Moreover, the discharge unit to be used may differ intentionally by pass. Thereby, the error of the discharge amount can be dispersed, and the amount of the disposed liquid material can be made uniform. However, if the combination of the discharge units to be used is different, the discharge amount with respect to the set value changes due to the difference in the state of pressure propagation when the liquid is pressurized in the discharge operation. Therefore, even if the discharge amount is adjusted based on the discharge amount evaluated as described above, the discharge amount does not become a predetermined amount during actual film formation.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a forming method that enables highly accurate evaluation of the discharge amount in each discharge unit and provides a good thin film.

  In the thin film forming method of the present invention, the droplet discharge head provided with a plurality of discharge units for discharging a liquid material containing a thin film forming material and the substrate to be processed are relatively scanned a plurality of times in a predetermined direction. A thin film forming method for forming a thin film by discharging the liquid material onto a substrate to be processed, wherein two or more of the plurality of discharge units are driven with a predetermined drive signal, and the liquid material is applied to an inspection substrate. An inspection process for inspecting the ejection amount of each discharged liquid material, an adjustment process for adjusting the predetermined drive signal based on an inspection result of the inspection process, and a drive signal adjusted in the adjustment process And forming a thin film by disposing the liquid material on the substrate to be processed by selectively discharging the plurality of discharge units and changing the discharge operation pattern of the selected discharge unit for each scan. A thin film forming step, wherein the inspection step selects two or more of a plurality of different discharge operation patterns in the thin film formation step, and the liquid material is applied to the inspection substrate based on the discharge operation pattern. It includes an arrangement process for arranging and an evaluation process for evaluating the volume of the liquid material arranged in the arrangement process.

According to this configuration, since the liquid material is arranged by the arrangement process in the inspection process based on the ejection operation pattern used in the thin film forming process, the ejection amount corresponding to the ejection operation pattern can be inspected. Therefore, it is possible to adjust the drive signal in accordance with the ejection operation pattern in the adjustment process, and it is possible to significantly reduce the variation in the ejection amount caused by making the ejection operation pattern different in the thin film formation process. . Therefore, in the thin film forming step, the liquid material can be arranged in a uniform amount, and a thin film pattern with a uniform film thickness can be formed.
Here, the discharge operation pattern is a series of operation patterns that define which discharge unit causes the discharge operation to be performed at which timing or position. For example, the operation patterns of the respective discharge units during one scan are combined for all the discharge units.

  Further, since the plurality of discharge units are selectively discharged in the thin film forming step, a thin film pattern can be formed. Therefore, the process cost and the material cost can be reduced as compared with the case where the thin film is patterned using a photolithography method, an etching method, or the like after the thin film is formed. Further, if the liquid material is arranged by changing the discharge operation pattern of the discharge unit to be selected for each scan, the liquid material can be arranged to overlap with one another using, for example, a plurality of discharge units. Thereby, the variation in the discharge amount can be dispersed, and the amount of the liquid material to be arranged can be made uniform.

In the placement process in the inspection step, a sub-placement process is performed in which the liquid material is placed with the relative position of the inspection substrate and the droplet discharge head fixed for each selected ejection operation pattern. The number of ejections that each of the plurality of ejection units performs the ejection operation in the arrangement process may be the same as the corresponding ejection operation pattern.
In this way, since the number of ejections of each ejection unit is made the same as the corresponding ejection operation pattern, the ejection amount corresponding to the ejection operation pattern is reflected in the amount of the liquid material arranged. That is, the liquid material can be arranged based on the ejection operation pattern. In the thin film forming process, the liquid material discharged from each discharge unit is arranged at a plurality of locations in a line shape. However, in the sub-arrangement process, the liquid material from each discharge unit is fixed because the relative position is fixed. It can be placed in one place. If the amount of the liquid material arranged in one place is inspected, the inspection process can be simplified and the inspection process can be made more efficient than inspecting the liquid material arranged in a plurality of places. In this way, it is possible to efficiently inspect the ejection amount according to the ejection operation pattern.

In the placement process in the inspection step, a sub-placement process is performed in which the liquid material is placed with the relative position of the inspection substrate and the droplet discharge head fixed for each selected ejection operation pattern. The number of discharges can be made equal in the plurality of discharge units, and the number of discharges can be the maximum number of discharges of the plurality of discharge units in the corresponding discharge operation pattern.
In this way, in the sub-arrangement process, the number of ejections of the plurality of ejection units is set as the maximum number of ejections in the ejection operation pattern, so that the liquid material can be arranged based on the ejection operation pattern. In addition, the liquid material from each discharge unit can be placed in one place and the inspection process can be made more efficient. In addition, by setting the maximum number of discharges in the thin film forming process, inspection of the number of discharges that are not actually used is not performed, so that the efficiency of the inspection process can be improved and the volume of the disposed liquid material can be maximized. As a result, the accuracy of measuring the volume is increased.

In the arrangement process of the inspection step, the liquid material is arranged in the inspection region of the inspection substrate, and the dummy liquid material containing the liquid composition solvent in the dummy inspection region surrounding the inspection region of the inspection substrate. Is preferably arranged.
The higher the concentration of the component of the volatile composition solvent (hereinafter referred to as the volatile component) in the atmosphere, the lower the volatilization rate of the composition solvent. Since the liquid material is more densely arranged in the center of the inspection region than the periphery, the concentration of volatile components in the atmosphere is increased.

  If the dummy liquid material is arranged around the inspection area as described above, the concentration of the volatile component at the periphery of the inspection area can be increased by the volatile component from the dummy liquid material, and this should be the same level as the center. Can do. Accordingly, the volatilization rate of the composition solvent becomes uniform between the liquid material arranged at the center of the inspection region and the liquid material arranged at the periphery, and the volume reduction of the liquid material due to volatilization becomes uniform. Therefore, the volume evaluation error due to volatilization is remarkably reduced, and it becomes possible to know an accurate discharge amount. Thus, since the volume of the liquid material arranged at a plurality of positions can be accurately known, the efficiency of the inspection process can be improved.

  Hereinafter, although one embodiment of the present invention is described, the technical scope of the present invention is not limited to the following embodiment. In the following description, various structures are illustrated using the drawings. However, in order to make the characteristic portions of the structure easy to see, the dimensions and scale of the structure are illustrated as appropriately different from the actual structure. Note that. Prior to the description of the thin film forming method of the present embodiment, a configuration example of a droplet discharge device will be described first. The droplet discharge device of this example is a device that selectively discharges a liquid material containing a color filter material and a solvent and solidifies it to form a color material portion of a color filter layer. Here, three types of liquid materials corresponding to red, green, and blue are discharged.

[Droplet discharge device]
FIG. 1 is a schematic perspective view showing the configuration of the droplet discharge device 100 of this example. As shown in FIG. 1, the droplet discharge device 100 includes a work stage 120 provided on a support base 110 and a droplet discharge head 140 provided at a position higher than the work stage 120.
Hereinafter, description will be made based on the XYZ orthogonal coordinate system shown in FIG. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the work stage 120, and the Z axis is set in a direction orthogonal to the work stage 120. Actually, the XY plane is set as a plane parallel to the horizontal plane, and the Z axis is set in the vertical upward direction.

  The work stage 120 can place the substrate 500 to be processed on the upper surface thereof. In addition, a vacuum suction device (not shown) or the like is provided, and the placed substrate 500 can be detachably fixed. The work stage 120 is provided with a stage moving mechanism 125. The stage moving device 125 includes a bearing mechanism such as a ball screw or a linear guide, and moves the work stage 120 in the X direction based on a control signal input from the control device 160. As a result, the substrate 500 to be processed can be moved to a predetermined position in the X direction.

  The droplet discharge device 100 of this example includes three droplet discharge heads 140 corresponding to each of three types (red, green, and blue) of color filter materials. All of the three droplet discharge heads 140 are attached to the carriage 130, and the carriage 130 is provided with a carriage moving device 135. The carriage moving device 135 moves the carriage 130 in the Y direction or the Z direction based on a control signal input from the control device 160. Thereby, the droplet discharge head 140 can be moved to a predetermined position in the Y direction or the Z direction.

  Each droplet discharge head 140 includes a large number of discharge units. Each discharge unit discharges a liquid material based on drawing data and control signals from the control device 160. Three types of liquid materials corresponding to the three types of color filter materials are stored in tanks 150A, 150B, and 150C, respectively. The stored liquid material is supplied to the corresponding droplet discharge head 140 through the tube group 155 for each type.

  2A to 2C are diagrams showing the configuration of the droplet discharge head 140. FIG. 2A is a plan view of nozzles provided in each discharge unit, FIG. 2B is an exploded perspective view showing the main part of the droplet discharge head 140, and FIG. 2C is the X direction of the discharge unit. FIG. The three droplet discharge heads 140 have the same configuration, and only one of them will be described here.

As shown in FIG. 2 (a), this embodiment of the liquid droplet ejection head 140 is provided with 180 ejection unit _U 1 _{~U 180} arranged in the Y direction, each of the discharging units _U 1 _{~U 180} Correspondingly, nozzles N _{1 to} N ₁₈₀ are provided. As shown in FIG. 2B, the droplet discharge head 140 includes a vibration plate 141 and a nozzle plate 142 that are provided apart from each other, and a partition wall 144 that is provided by partitioning them. . A space partitioned by the partition wall 144 is a cavity 145, and one cavity 145 corresponds to one discharge unit. Corresponding to each of the discharge units U _{1 to} U ₁₈₀ , nozzles N _{1 to} N ₁₈₀ are provided on the nozzle plate 142, and piezoelectric elements (drive elements) PZ _{1 to} PZ ₁₈₀ are provided on the vibration plate 141. ing. The piezoelectric elements PZ _{1 to} PZ ₁₈₀ are, for example, piezoelectric elements.

  The plurality of cavities 145 communicate with a common liquid reservoir 143 through supply holes 145a corresponding to the cavities 145, respectively. The diaphragm 141 is provided with an inlet 141a corresponding to the liquid reservoir 143, and one of the tube groups 155 is connected to the inlet 141a. With such a configuration, the liquid material supplied from the connected tube is stored in the liquid reservoir 143 through the inlet 141a, and further filled into each cavity 145 through the supply hole 145a. .

As shown in FIG. 2 (c), the piezoelectric elements PZ ₁ includes a piezoelectric material 146, and a pair of electrodes 147 that sandwich it. A drive circuit board (described later) for supplying drive signals to the piezoelectric elements PZ _{1 to} PZ ₁₈₀ is provided corresponding to the droplet discharge head 140. The driving circuit board is connected to the control unit 160, based on the drawing data and control signals input from the control unit 160, actually selected piezoelectric elements PZ ₁ to PZ ₁₈₀ to supply the driving voltage waveform, driving Signal generation, ejection timing control, and the like are performed.

When a drive signal is supplied from the drive circuit board, a voltage is applied between the pair of electrodes 147, and the piezoelectric material 146 contracts by a strain amount corresponding to the voltage value. Then, the vibration plate 141 in the arrangement portion of the piezoelectric element PZ ₁ is flexed outwardly (opposite to the cavity 145) integral with the piezoelectric element PZ _1. As a result, the volume of the cavity 145 increases, and the increased volume of the liquid material flows from the liquid pool 143 into the cavity 145.

When the application of the voltage between the pair of electrodes 147 is stopped, the piezoelectric elements PZ ₁ and the vibrating plate 141 both return to their original shapes, the cavity 145 is returned to the original volume. Then, the pressure of the liquid rises in the cavity 145, the droplet L of the liquid is discharged toward the nozzle N ₁ on the color filter substrate P. The discharge amount of the liquid material, that is, the volume of the droplet L is based on the volume change amount of the cavity 145 and can be adjusted by the voltage value applied between the pair of electrodes 147.

FIG. 3 is a schematic diagram showing the circuit configuration of the droplet discharge head 140 and the drive circuit board 200. As shown in FIG. 3, the drive circuit board 200 includes an interface 210, a drawing data memory 220, a waveform selection circuit 230, and first to fourth D / A converters 240A to 240D. The droplet discharge head 140 includes a COM selection circuit 170, a switching circuit 180, and a piezoelectric element group 190 including the piezoelectric elements PZ _{1 to} PZ ₁₈₀ .

  The interface 210 is connected to the control device 160 (see FIG. 1) via a PCI bus or the like (not shown). The control device 160 outputs drawing data SI including ejection data SIA and COM selection data SIB, various control signals such as a clock signal and a latch signal for driving and controlling the circuit, and the like. The drawing data SI and various control signals are written in the drawing data memory 220. The drawing data memory 220 is, for example, a 32-bit SRAM.

The discharge data SIA is data defining a discharge operation pattern. That is, the data defines whether or not to supply a drive signal to each of the discharge units U _{1 to} U ₁₈₀ according to the position of the droplet discharge head 140. For example, the thin film pattern to be formed is divided into a matrix, and the bitmap data is obtained by mapping on / off of the discharge operation in each divided bit by binary data.

  The COM selection data SIB is data that defines a drive signal for each discharge unit. Here, one of four types of drive signals COM1 to COM4 is selected for each discharge unit. The COM selection data SIB includes drive waveform number data WN that defines the waveforms of the drive signals COM1 to COM4 and data that defines which of the drive signals COM1 to 4 is selected for each ejection unit.

  The drawing data memory 220 outputs ejection data SIA as serial data to the switching circuit 180 of the droplet ejection head 140 in response to data read requests by various control signals, and ejects droplets as COM selection data SIB as serial data. The data is output to the COM selection circuit 170 of the head 140. The drive waveform number data WN is output to the waveform selection circuit 230.

  The waveform selection circuit 230 reads the waveform data specified by the drive waveform number data WN from the waveform data (for example, 64 types) stored in advance, and stores it in the address corresponding to the ejection data SIA. Further, in response to a data read request by various control signals, the drive waveform data stored in the designated address is output to each D / A converter.

  The first D / A converter 240A holds drive waveform data input from the waveform selection circuit 230 in synchronization with various control signals. Further, the drive waveform data is converted into an analog signal to generate a drive signal COM1 and output to the COM selection circuit 170 of the droplet discharge head 140. Similarly, the second D / A converter 240B generates the drive signal COM2, the third D / A converter 240C generates the control signal COM3, and the fourth D / A converter 240D generates the drive signal COM4. The data is output to the COM selection circuit 170.

The COM selection circuit 170 is controlled by various control signals, and outputs each of the piezoelectric element drive signals V _{1 to} V ₁₈₀ to the switching circuit 180 based on the COM selection data SIB. The switching circuit 180 is controlled by various control signals, and turns on / off the drive signals V _{1 to} V ₁₈₀ for each discharge unit based on the discharge data SIA. Thereby, a predetermined drive signal is supplied to a predetermined piezoelectric element among the piezoelectric elements PZ _{1 to} PZ ₁₈₀ provided corresponding to each discharge unit. The piezoelectric element to which the drive signal is supplied discharges a liquid material having a discharge amount corresponding to the voltage value applied between the pair of electrodes 147 as described above.

[How to use the droplet discharge device]
Next, a method for using the droplet discharge device 100 will be described. First, as shown in FIG. 1, a substrate to be processed (color filter substrate) 500 carried by a transfer device or the like (not shown) is placed on the upper surface of the work stage 120, and is attached or detached here by the vacuum suction device or the like. Fix it as possible. Then, the work stage 120 is moved by the stage moving mechanism 125, and the droplet discharge head 140 is moved by the carriage moving device 135 to adjust the relative position between the substrate to be processed 500 and the droplet discharge head 140. Further, the liquid material is disposed by causing the droplet discharge head 140 to perform a discharge operation at a predetermined relative position. Here, one pass is performed by a plurality of scans (scanning), and a predetermined amount of liquid material is arranged by a plurality of passes.

  FIG. 4 is a plan view schematically showing a liquid material arranging method. As shown in FIG. 4, a lattice-like bank 510 is formed on the color filter substrate 500. A portion partitioned by the bank 510 corresponds to one pixel. Here, the pixel has a substantially rectangular shape extending in the Y direction, and includes a pixel 520R corresponding to red, a pixel 520G corresponding to green, and a pixel 520B corresponding to blue. The pixels are arranged in the Y direction for each corresponding color, and pixels corresponding to red, green, and blue are periodically arranged in the X direction.

In addition, a droplet discharge head 140R corresponding to red, a droplet discharge head 140G corresponding to green, and a droplet discharge head 140B corresponding to blue constitute a set to form a droplet discharge head group. Here, by moving the substrate 500 to be processed in the X direction, the droplet discharge head group and the substrate 500 to be processed are relatively scanned in the X direction. Further, by causing the discharge unit selected from the discharge units U _{1 to} U ₁₈₀ to perform a discharge operation at a predetermined timing, the liquid materials are arranged in a line along the arrangement direction (Y direction) of the discharge units U _{1 to} U _180. . By repeating such a discharge operation, the liquid material is arranged over a predetermined width in the Y direction of the substrate 500 to be processed. This corresponds to one scan, and one type of ejection operation pattern is associated with one scan.

  Next, the droplet discharge head 140 is moved in the Y direction, and the second scan is performed by making the position in the Y direction different from the previous scan. By performing such a scan a plurality of times, the liquid material is disposed over the entire film formation region of the substrate 500 to be processed. This corresponds to one pass. By performing such a pass a plurality of times, a predetermined amount of liquid material is disposed. Here, one pass is performed in three scans, and a predetermined amount of liquid material is arranged in eight passes. Here, since a total of 24 scans are performed, there are a maximum of 24 types of ejection operation patterns.

For example, the pixel size is determined by the design of the color filter substrate 500, and the interval (nozzle pitch) between the nozzles N _{1 to} N ₁₈₀ is determined by the design of the droplet discharge head 140. Accordingly, when the scanning direction is selected and the color filter substrate 500 and the droplet discharge head group are arranged, the number of discharge units (for example, 24 to 25) passing through one pixel is determined during the scan. Further, the amount of the liquid material arranged in one pixel is calculated based on the thickness of the color filter layer to be formed, the size of the pixel, and the composition of the liquid material. The number of ejections (for example, 100 times) ejected to one pixel is calculated from the amount of the liquid material and the ejection amount of one ejection unit. Since this is arranged in 8 passes, the number of ejections per pixel is about 12 to 13 in one pass. In each scan, about 12 to 13 of 24 to 25 ejection units assigned to one pixel may be selected and ejected for each predetermined position. In this way, by selecting an ejection unit to be used for each pixel and determining the combination for each pixel arranged in the X direction, the ejection operation pattern in one scan is determined.

  By the way, the droplet discharge head is generally designed so that the characteristics of the plurality of discharge units are the same. However, due to variations in the volume of the cavity due to processing errors and the like, variations in the characteristics of the piezoelectric elements, and the like, in reality, even if the discharge operation is performed with the same voltage value, the discharge amounts in the plurality of discharge units vary. Moreover, the discharge amount with respect to a setting value may change with the combination of the discharge units to be used, and the discharge amount may vary. For example, when attention is paid to one discharge unit, the discharge amount may change depending on whether or not the adjacent discharge unit is operated. The reason may be that the propagation of pressure through a liquid pool or the like changes. When the variation in the discharge amount as described above occurs, the film thickness unevenness occurs in the formed thin film. Such inconvenience occurs in the droplet discharge head using any discharge technology such as electromechanical conversion type, charging control method, pressure vibration method, electrothermal conversion method, electrostatic suction method, etc. End up.

  If the drive signal can be selected and supplied for each discharge unit as in the droplet discharge device 100 of this example, the discharge amount of each discharge unit can be adjusted by the drive signal. Thus, it is possible to reduce the variation in the discharge amount among the plurality of discharge units. Needless to say, it is important to accurately know the discharge amount of each discharge unit corresponding to the discharge operation pattern from the viewpoint of appropriately adjusting the discharge amount. Therefore, in the present invention, the discharge amount of each discharge unit corresponding to the discharge operation pattern is measured with high accuracy, and after adjusting the drive signal based on the measurement result, the thin film is formed. Hereinafter, an embodiment of a thin film forming method according to the present invention will be described.

[Thin film formation method]
FIGS. 5A to 5C are process diagrams schematically showing the arrangement process of the inspection process in the thin film forming method of the present embodiment, and are diagrams showing the arrangement surface of the liquid material in plan view. The present embodiment is an example in which the thin film forming method of the present invention is applied to the formation of a color filter layer.

  First, as shown in FIG. 5A, an inspection substrate 300 is prepared. In this embodiment, the ejection amount is measured later using an optical interference method. When the optical interference method is used, the measurement accuracy varies depending on the contact angle between the inspection substrate 300 and the liquid. For example, when the contact angle is less than 50 °, the liquid material is thinly spread. Then, the arranged liquid body becomes unclear in its outline, and the amount of change in thickness becomes small, so that the measurement accuracy becomes low. For example, if the contact angle is greater than 70 ° and less than 90 °, the amount of change in thickness at the end of the disposed liquid material increases, and the interval between the interference fringes is reduced, resulting in a decrease in measurement accuracy. . For example, when the contact angle is 90 ° or more, the bottom surface side of the end portion of the disposed liquid material is shaded from the light source above the disposed surface, and this portion cannot be measured.

  For the above reasons, in this embodiment, the inspection substrate 300 is selected so that the contact angle with the liquid material is 50 ° or more and 70 ° or less. For example, the material of the inspection substrate may be selected, and the contact angle may be adjusted by lyophobic / lyophilic treatment. Here, the inspection substrate 300 having a substantially rectangular shape in plan view is employed, and the long side direction is defined as the Y direction, and the short side direction is defined as the X direction. The X direction and the Y direction correspond to the XYZ orthogonal coordinate system shown in FIG.

  Further, in the inspection substrate 300, a portion where the liquid material is disposed later is set as an inspection region, and a portion surrounding the inspection region is set as a dummy inspection region. Here, a substantially rectangular portion in plan view at the center of the inspection substrate 300 is defined as an inspection region A1, and a portion surrounding the inspection region A1 in a frame shape is defined as a main dummy inspection region (dummy inspection region) A2 and a main dummy inspection region A2. A portion surrounded by a frame is defined as a sub dummy inspection region (dummy inspection region) A3.

  Next, as shown in FIG. 5B, the dummy liquid material 310a is disposed in the main dummy inspection region A2, and the dummy liquid material 310b is disposed in the sub dummy inspection region A3. The dummy liquid materials 310a and 310b contain at least the composition solvent of the liquid material. In this embodiment, droplets of the same solution as the liquid material are arranged using the droplet discharge device 100, and these are used as dummy liquid materials 310a and 310b. The volume of the dummy liquid materials 310a and 310b is set to be equal to or greater than the maximum value of each volume in the liquid material to be disposed later. In addition, the interval between the dummy liquid materials 310a and 310b is approximately the same as the nozzle pitch in both the portion along the X direction and the portion along the Y direction.

  Next, as illustrated in FIG. 5C, the liquid material 320 is disposed in the inspection region A <b> 1 using the droplet discharge device 100. For example, the ejection operation pattern used in the subsequent thin film forming process is used as it is, or the nozzle duty, which is the ratio of the number of ejection units to be ejected and the number of ejection units not to be ejected, is set to the same level as the ejection operation pattern, The liquid 320 can be arranged based on the discharge operation pattern, for example, by setting the number of discharges to be performed by the discharge unit to the same level as the discharge operation pattern. Note that two or more of the plurality of ejection operation patterns used in the thin film forming process are selected and the arrangement process is performed. As the number of ejection operation patterns to be selected is increased, the inspection process can be performed under conditions closer to the thin film formation process. Here, the inspection process is performed for all the ejection operation patterns.

  Here, by using the number of ejections of each ejection unit in the ejection operation pattern as a parameter, arrangement processing is performed in correspondence with the ejection operation pattern. In this embodiment, in the thin film forming process, one pass is performed by three scans, and a predetermined amount of liquid material is arranged by eight passes. Accordingly, there are 24 types of ejection operation patterns, and the arrangement process is performed correspondingly.

  First, the relative position between the droplet discharge head 140 and the inspection substrate 300 is fixed, and the liquid material is discharged in a first discharge operation pattern selected from these 24 types. That is, while the liquid material is ejected while scanning in the thin film forming process, the relative position is fixed in the inspection process, and the liquid material is ejected at the timing of the ejection operation in the ejection operation pattern. Thereby, the combination of the discharge unit used in one discharge operation becomes the same as that of the thin film forming process. In addition, the number of discharges of each discharge unit is the same in the placement process and the thin film forming process. In the thin film forming process, the liquid material is two-dimensionally arranged, but in the inspection process, the liquid material is arranged so as to overlap one place for each discharge unit. In this way, the liquid materials 320 are arranged in a line along the Y direction at intervals similar to the nozzle pitch. Further, the liquid material 320 is arranged so that the distance between the liquid material 320 and the dummy liquid material 310a arranged in the main dummy inspection area A2 is approximately the same as the nozzle pitch in the X direction and the Y direction.

  In addition, if the number of shots of each discharge unit in the first discharge operation pattern is increased by a predetermined magnification, the volume of the liquid 320 to be arranged increases, and the accuracy in the subsequent evaluation process can be increased. In this case, the discharge amount per discharge of each discharge unit can be calculated by dividing the measured volume by the predetermined magnification and the number of discharges.

  Next, after the inspection substrate 300 is moved by about the nozzle pitch in the X direction, the liquid material 320 is arranged based on a second ejection operation pattern selected from the 24 types and different from the first ejection operation pattern. To do. Similarly, the liquid material 320 is arranged by sequentially repeating the movement of the droplet discharge head 140, the change of the discharge operation pattern, and the arrangement of the liquid material 320. As a result, the liquid bodies 320 are arranged in a row along the Y direction for each ejection operation pattern, and a two-dimensional array in which such columns are arranged in the X direction corresponding to 24 types of ejection operation patterns is obtained. It is done. The liquid material 320 arranged at the periphery of the two-dimensional array is spaced from the dummy liquid material 310a arranged in the main dummy inspection area A2 at equal intervals in the X direction and Y direction (here, about the nozzle pitch). ).

Further, since the dummy liquid material 310a is disposed in the main dummy inspection region A2, the liquid material 320 or the dummy liquid material 310a is similarly disposed around any of the disposed liquid materials 320. For example, three liquid bodies 320 and five dummy liquid bodies 310a are disposed around the liquid body 320 disposed at the corner of the inspection area A1. Five liquid bodies 320 and three dummy liquid bodies 310a are arranged around the arranged liquid body 320 at the periphery excluding the corner of the inspection region A1. Eight liquid bodies 320 are arranged on the inner side (center side) of the periphery of the inspection area A1 and around the liquid bodies 320.
Thus, in the present embodiment, a total of eight liquid bodies 320 or dummy liquid bodies 310a are arranged around the liquid body 320 regardless of the arrangement position thereof.

  Next, the volume of each of the liquid materials 320 arranged on the inspection substrate 300 is evaluated (evaluation process). As a method for evaluating the discharge amount, a method of measuring the weight or a method of measuring the volume thereof can be considered. The discharge amount of each discharge unit is very small, and it is difficult to measure its weight individually from the viewpoint of measurement accuracy and work efficiency. In the present invention, by adopting a method for measuring the volume, it is possible to evaluate the discharge amount with higher accuracy than measuring the weight. In the present embodiment, a vertical scanning white light interferometry is used as a volume measuring method.

  In the white light interferometry, the light is separated into reference light and measurement light by a beam splitter or the like, and the measurement object (here, the liquid 320) is irradiated with the measurement light. The measurement light reflected on the surface of the measurement object and the reference light are overlapped by optical means to become interference light. By examining the intensity of the interference light, the optical path difference between the reference light and the measurement light can be obtained. The thickness of the portion irradiated with the measurement light can be obtained from the optical path difference, and the shape of the measurement object can be known. From this shape data, the volume of the measurement object can be calculated.

  The volume of the liquid 320 arranged on the inspection substrate 300 is evaluated by the white light interferometry as described above. The evaluation of the volume may be performed at any timing immediately after the liquid 320 is disposed, in the process of drying the liquid 320, or after the liquid 320 is dried. Here, the evaluation process is performed after the liquid 320 is dried.

  The solvent of the liquid 320 and the dummy liquids 310a and 310b arranged on the inspection substrate 300 is volatilized over time. The higher the concentration of the volatile component in the atmosphere, the lower the volatilization rate of the solvent, and the concentration of the volatile component increases corresponding to the portion where the liquid 320 and the dummy liquids 310a and 310b are densely arranged. That is, in the inspection area A1 and the main dummy inspection area A2, since the liquid 320 or the dummy liquid 310a is uniformly arranged, the concentration of the volatile component becomes almost uniform, and the volatilization rate of the solvent becomes uniform. In the sub dummy inspection area A3, the concentration of the volatile component decreases from the inner side (main dummy inspection area A2 side) to the outer side, and the volatilization rate increases from the inner side to the outer side.

  When the solvent is volatilized, in the inspection area A1 and the main dummy inspection area A2, the liquid 320 and the dummy liquid 310a are uniformly vaporized at any arrangement position, so the volume reduction becomes uniform. Further, when paying attention to each liquid 320, since the partial volatilization rate is uniform, drying proceeds while maintaining symmetry between the central side and the peripheral side of the inspection region A1.

  And in the state which the liquid 320 dried and solidified, the volume is measured using the above-mentioned white light interferometry. Since the solid substance which the liquid 320 solidified has the favorable symmetry of the shape, it can measure favorably. That is, if an attempt is made to measure an object having a low shape symmetry, high-resolution measurement, advanced analysis, and the like are required, which increases measurement effort, time, and apparatus cost. If the dummy liquid material 310a is disposed around the liquid material 320, such inconvenience can be avoided, and measurement accuracy can be improved and efficiency can be improved.

  Based on the volume of the solid material thus obtained, the volume value of each liquid material 320, the relative volume ratio of the plurality of liquid materials 320, and the like can be evaluated. Here, the volume of the liquid 320 is calculated using the measured volume of the solid and the composition ratio of the solvent in the liquid 320. Since the solid matter is uniformly dried regardless of the arrangement position, the difference in volume due to the difference in the degree of drying is eliminated. In addition, since the difference in volatilization rate of the liquid material depending on the arrangement position can be eliminated, the volume of a large number of liquid materials can be evaluated while ensuring accuracy. Therefore, it is possible to efficiently evaluate the discharge amount of each discharge unit in a plurality of discharge operation patterns. The amount of each liquid material is a total amount of the discharge units of the discharge units in the discharge operation pattern while reflecting the combination of discharge units used in the discharge operation pattern. Therefore, by evaluating the amount, it is possible to know the average value of the discharge amount of each discharge unit in one discharge operation pattern.

  Next, the drive signal supplied to the discharge unit in the thin film formation step is adjusted based on the discharge amount obtained in the inspection step (adjustment step). Different drive signals (for example, 180 types) can be prepared for each discharge unit, but the number of components, device cost, power consumption, and the like increase. Therefore, in the present embodiment, the discharge amount of each discharge unit is set to approach the appropriate weight using the four types of drive signals as described above. This is because by using four or more types of drive signals, it is possible to suppress variations in the discharge amount within a predetermined range and to prevent the uneven stripes from being visually recognized. Hereinafter, the adjustment process will be described with reference to FIGS.

FIG. 6 is a graph showing an example of the discharge amount obtained in the inspection process. In FIG. 6, the horizontal axis indicates the numbers of the discharge units U _{11 to} U ₁₇₀ , and the vertical axis indicates the discharge amount. The discharge amount is calculated based on the volume of the liquid 320. As shown in FIG. 6, the discharge amounts of the discharge units U _{11 to} U ₁₇₀ increase as they are arranged at both ends. Although not shown, the discharge amounts from the discharge units U _{1 to} U ₁₀ and U _{171 to} U ₁₈₀ are further increased, and these are not used in the subsequent thin film forming step from the viewpoint of reducing the discharge amount variation. To do.

In the adjustment process of the present embodiment, the discharge units U _{11 to} U ₁₇₀ are first divided into a plurality of groups based on the discharge amount distribution shown in FIG. Each group belongs to a discharge unit that is driven by the same drive signal. In this embodiment, since four types of drive signals are used, it is divided into four groups. Here, the range from the minimum weight to the maximum weight is equally divided into four, and range 1, range 2, range 3, and range 4 are set in ascending order. Further, the group 1 is configured by the discharge units having the discharge amount within the range 1, and the groups 2 to 4 are similarly configured corresponding to the ranges 2 to 4.

Next, based on a relational expression of the discharge amount with respect to the voltage applied to the piezoelectric element of the discharge unit, a voltage (corrected drive voltage) that becomes a predetermined discharge amount is calculated. The formula for obtaining the correction drive voltage is expressed by the following formula (1), for example. In Expression (1), V0 is an applied voltage before correction, and K is a coefficient obtained in advance through experiments or the like. In the formula (1), the statistical value “center weight of the range” may be replaced with the statistical value “average weight of the discharge unit in each range”.
Corrected drive voltage = V0−K. (Center weight of range−appropriate weight) (1)

  Then, the drive signal COM1 supplied to the piezoelectric element is set based on the corrected drive voltage calculated for the group 1, and similarly, the drive signals COM2 to 4 corresponding to the groups 2 to 4 are set. In the inspection process, discharge amounts corresponding to each of the 24 types of discharge operation patterns are obtained, and a method for statistically processing the data can be appropriately selected. For example, the drive signals COM1 to COM4 may be set for each of 24 types of ejection operation patterns, and the average value of the 24 types of ejection operation patterns is used as the ejection amount of each ejection unit, and is common to the ejection operation patterns. The drive signals COM1 to COM4 may be set. Here, drive signals COM1 to COM4 as shown in FIG. 7 are set using the average value, and drawing data SI and the like corresponding thereto are created.

  FIG. 8 is a graph showing a comparison of the distribution of the discharge amount (before correction) obtained in the inspection process and the distribution of the discharge amount (after correction) by the control signals COM1 to 4 set in the adjustment process. The corrected ejection amount is also evaluated in the same manner as in the inspection process. As shown in FIG. 8, after the correction, the discharge amount is almost equal to the appropriate weight after the correction, and the variation in the discharge amount is remarkably reduced. According to the present invention, it is considered that the ejection amount can be evaluated with high accuracy in the inspection process, and the drive signals COM1 to COM4 can be appropriately set in the adjustment process. Also in such a comparison, the corrected ejection amount can be measured and evaluated with high accuracy, so that it is possible to confirm that the drive signals COM1 to COM4 are appropriately set. In addition, when the variation in the ejection amount after correction is more than the allowable range, the inspection process and the adjustment process may be performed again using the drive signals COM1 to 4 at this time. In this case, since the inspection process is performed under conditions closer to the thin film forming process, the discharge amount can be made closer to the set value.

Next, the droplet discharge device 100 is operated as described in [Method of using droplet discharge device] to perform a thin film forming process. Specifically, a substrate 500 to be processed which is a color filter substrate is detachably fixed to the work stage 120 shown in FIG. Then, while changing the relative position between the substrate 500 to be processed and the droplet discharge head 140, one pass is performed by three scans, and a predetermined amount of liquid material is arranged by eight passes. In each of 24 scans, the ejection operation is performed using the drive signals COM1 to COM4 adjusted in the adjustment process. As a result, the discharge amount can be set to an appropriate weight as shown in FIG. 8, and variations in the discharge amount can be reduced. Accordingly, it is possible to arrange a predetermined amount of the liquid material and arrange a uniform amount of the liquid material.
Moreover, a color filter layer (thin film) can be obtained by appropriately drying and solidifying the disposed liquid.

  In the thin film forming method of the present invention as described above, it is possible to evaluate the discharge amount corresponding to the discharge operation pattern in the thin film forming process with high accuracy and efficiency. Therefore, the drive signal of the discharge unit can be appropriately set in the adjustment process, and the variation in the discharge amount can be significantly reduced. Therefore, a predetermined amount of liquid material can be disposed, and a thin film having a uniform thickness can be formed. For example, if the present invention is applied to the formation of a color filter layer, a color filter layer having a uniform film thickness can be formed. Therefore, the color filter layer can be made to function without causing unevenness and the like, and the display quality of the image display apparatus provided with this can be improved.

In order to form such a thin film by a conventional method, high-precision processing is required so that the variation in characteristics among a plurality of discharge units is reduced. Therefore, inconveniences such as an increase in cost of the droplet discharge device and a decrease in yield have occurred.
According to the present invention, since a good thin film can be obtained by adjusting the drive signal, a processing error or the like allowed for the droplet discharge head is increased. Therefore, the manufacturing cost of the droplet discharge head can be reduced, the process of selecting the droplet discharge head can be simplified or omitted, the yield of the droplet discharge head can be improved, and the cost of the droplet discharge apparatus can be reduced. A ripple effect is also obtained.

In the above-described embodiment, the dummy liquid material and the liquid material are arranged by independent processes, but may be arranged by the same process. For example, a dummy liquid material is arranged in parallel with a part of the ejection units U _{1 to} U ₁₈₀ provided in the droplet ejection head 140 or from another droplet ejection head 140 attached to the carriage 130. A liquid material may be disposed.

  Further, the effect can be obtained by using only the main dummy inspection region A2 as the dummy inspection region, but the effect can be enhanced by using the sub dummy inspection region A3 together. In addition to arranging the dummy liquid material in a single frame shape in the sub dummy inspection region A3, it may be arranged in a double or more frame shape. Further, the volume of the liquid material may be measured under conditions different from the discharge operation pattern. In addition, there may be a plurality of inspection regions, and for example, the liquid material may be arranged with a different ejection operation pattern for each of the plurality of inspection regions.

  Further, the liquid material and the dummy liquid material may be arranged in a staggered form in whole or in part, in addition to arranging the liquid material and the dummy liquid material in a matrix arranged at equal intervals in the X direction and the Y direction. A staggered pattern is an arrangement in which, for example, columns arranged in the X direction are also arranged in the Y direction, and the positions of elements in each column are shifted in the X direction between adjacent columns.

  Further, the timing for measuring the volume of the liquid 320 in the inspection process may be a process in which the liquid 320 is dried. In this case, the volatilization rate of the solvent contained in the liquid 320 is examined in advance, and the volume of the discharge amount is determined based on the time from the disposition of the liquid 320 to the measurement, the volatilization rate of the solvent, and the measurement result. Can be calculated.

  Further, the present invention can be applied in addition to the formation of the color filter layer. For example, solid films such as alignment films for liquid crystal devices, protective films such as overcoats, functional layers such as organic light emitting layers and hole injection (transport) layers in organic electroluminescence devices, spacers made of metal wiring, resins, etc. If the present invention is applied to the case where the uniformity of the ejection amount is required when forming the thin film pattern, the effect can be obtained.

It is a schematic perspective view which shows the structural example of a droplet discharge apparatus. (A)-(c) is a figure which shows the structural example of a droplet discharge head. It is a schematic diagram showing a droplet discharge head and a drive circuit board circuit configuration. It is a top view which shows typically the arrangement | positioning method of a liquid body. (A)-(c) is process drawing which shows typically the arrangement | positioning process of an inspection process. It is a graph which shows an example of the discharge amount obtained by the test result. It is a graph which shows the example of a drive signal. It is a graph which shows the comparison of the distribution of the discharge amount before and behind correction | amendment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Droplet discharge apparatus, 140, 140R, 140G, 140B ... Droplet discharge head, 147 ... Piezoelectric element (drive element), 200 ... Drive circuit board, 300 ... Measurement board 310a, 310b ... dummy liquid material, 320 ... liquid material, 500 ... substrate to be processed, A1 ... inspection area, A2 ... main dummy inspection area (dummy inspection area), A3 ... Sub dummy inspection area (dummy inspection area), COM1 to COM4, control signal, N _{1 to} N _180, nozzle, U _{1 to} U _180, discharge unit

Claims (4)

The liquid material is applied to the substrate to be processed while the droplet discharge head having a plurality of discharge units for discharging the liquid material containing the thin film forming material and the substrate to be processed are scanned relatively several times in a predetermined direction. A thin film forming method for discharging and forming a thin film,
An inspection step of driving two or more of the plurality of discharge units with a predetermined drive signal to discharge the liquid material onto an inspection substrate and inspecting the discharge amount of each of the discharged liquid materials;
An adjustment step of adjusting the predetermined drive signal based on the inspection result of the inspection step;
The liquid material is applied to the substrate to be processed by using the drive signal adjusted in the adjustment step, selectively discharging the plurality of discharge units, and changing the discharge operation pattern of the selected discharge unit for each scan. And a thin film forming step of forming a thin film,
The inspection step selects two or more of a plurality of different discharge operation patterns in the thin film formation step, and arranges the liquid on the inspection substrate based on the discharge operation patterns, and the arrangement processing And an evaluation process for evaluating the volume of the liquid material arranged in (1).   In the placement process in the inspection step, a sub-placement process is performed in which the liquid material is placed with the relative position of the inspection substrate and the droplet discharge head fixed for each selected ejection operation pattern. 2. The thin film forming method according to claim 1, wherein the number of times of ejection performed by each of the plurality of ejection units is the same as a corresponding ejection operation pattern.   In the placement process in the inspection step, a sub-placement process is performed in which the liquid material is placed with the relative position of the inspection substrate and the droplet discharge head fixed for each selected ejection operation pattern. 2. The thin film forming method according to claim 1, wherein the number of ejections is equalized in the plurality of ejection units, and the number of ejections is set as the maximum number of ejections of the plurality of ejection units in a corresponding ejection operation pattern.   In the arrangement process of the inspection step, the liquid material is disposed in the inspection region of the inspection substrate, and the dummy liquid material containing the liquid composition solvent in the dummy inspection region surrounding the inspection region of the inspection substrate. The thin film forming method according to claim 1, wherein the thin film is disposed.

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