JP4270052B2 - Thin film forming method, stage device - Google Patents

Description

  The present invention relates to a thin film forming method, a device manufacturing method, and a stage apparatus.

In recent years, a method using an ink jet apparatus has been proposed as a method for forming a functional layer including a color filter. In the inkjet device, for example, a color filter is easily manufactured by discharging each droplet onto a glass substrate while scanning an inkjet head filled with droplets of red, green, and blue pigments. It becomes possible. In addition, the application range of the ink jet device and the ink jet method includes not only a color filter manufacturing process but also a process of drawing a liquid containing a metal material in a predetermined pattern to form a metal wiring, a light emitting material, and a hole injection material. It can also be used in the process of drawing a liquid material to form pixels. That is, the ink jet device can be applied to the manufacturing process of various functional layers as long as it is a functional material that is dispersed or dissolved in a dispersion or solution.
By the way, in the film-forming process using an inkjet apparatus, in order to prevent film unevenness and improve the landing accuracy, the liquid material drawing process and the drying process are performed with the substrate adsorbed on the stage and without bending. However, when the substrate is vacuum-adsorbed in this way, when the liquid material is dried, the film thickness of the dry film may be non-uniform with the portion that is not vacuum-adsorbed. This may be due to local deflection of the substrate when the substrate is vacuum-adsorbed. In Patent Document 1, as a countermeasure, a method is proposed in which a flexible rubber having a structure in which air can be fed between the substrate and the stage is sandwiched between the substrate and the stage, and the deflection of the substrate due to adsorption is corrected by adjusting the introduced air. is doing.
JP 2000-223388 A

However, in this method, the solvent applied to the substrate wraps around the back surface of the substrate and rubber elution occurs, which may reduce the yield. Moreover, in order to form a uniform thin film, it is necessary to manage the temperature of the introduced air, and the control becomes complicated.
The present invention has been made in view of such circumstances, and in the thin film forming process using the droplet discharge method, prevents the occurrence of drying unevenness that occurs when the drying process is performed with the substrate adsorbed to the stage. An object of the present invention is to provide a thin film forming method and a device manufacturing method. Another object of the present invention is to provide a stage apparatus suitable for use in such a thin film forming process.

In order to solve the above problems, a thin film forming method of the present invention includes a step of disposing a liquid material containing a functional material as droplets on a substrate and drying the droplets to form a film. The droplet drying step is performed in a state in which a region other than the droplet arrangement region of the substrate is adsorbed and the substrate is held on a stage device.
In this method, the substrate is adsorbed at a position that avoids the droplet placement area (that is, the thin film formation area). Therefore, even if the adsorption position is locally bent, unevenness is caused in the dry state of the thin film. It does not occur.

In the thin film forming method of the present invention, the stage device includes a mounting table formed on a substantially flat surface, and a plurality of suction holes for sucking the substrate are provided on the surface of the mounting table. The drying step may be performed in a state where the substrate is sucked into the suction hole of the mounting table.
In this method, the structure of supporting the substrate on the surface is adopted, so that the structure of the mounting table is simplified, and the present invention can be handled only by changing the suction position of the conventional stage device.

In the thin film forming method of the present invention, the stage device includes a mounting table provided with a plurality of protruding support pins each having a suction hole formed at a tip thereof, and the droplet drying step supports the substrate. It can be performed in a state where it is adsorbed in the adsorption hole of the pin.
In this method, since the back surface side of the substrate can be held in a state of being substantially lifted from the mounting table, the substrate can be heated uniformly from both the front surface side and the back surface side. Therefore, as compared with the configuration in which the substrate is supported on the surface as described above, the temperature distribution of the substrate is reduced and drying unevenness can be further reduced.

In the thin film forming method of the present invention, a gas jet port for jetting gas toward the back side of the substrate is provided between the support pin and the support pin of the mounting table, and the drying process of the droplets is performed as described above. Gas can be blown from the gas outlet to the back side of the substrate, and the portion of the substrate not supported by the support pins can be supported by the pressure of the gas.
In the configuration in which the substrate is supported by the support pins as described above, the portion of the substrate that is not supported by the support pins bends, and film thickness unevenness may occur in the bent portion. In this method, the portion that is not supported by the support pins is floated by the gas injection pressure, so that such film thickness unevenness does not occur.

In the thin film forming method of the present invention, the temperature of the gas may be set to substantially the same temperature as the drying temperature in the drying step.
By carrying out like this, a board | substrate can be heated uniformly from the both surface sides of a surface side and a back surface side.

The device manufacturing method of the present invention is a device manufacturing method including a thin film forming step, wherein the thin film is formed by the above-described thin film forming method of the present invention.
Thereby, quality improvement of a device can be achieved.

The stage apparatus of the present invention is arranged on the substrate in a thin film forming step including a step of disposing a liquid material containing a functional material as a droplet on the substrate and drying the droplet to form a film. A stage device used for sucking and holding the substrate when drying the droplets, comprising a mounting table in which a suction hole for sucking the substrate is formed, the suction hole being a thin film of the substrate It is arranged in a region other than the formation region.
In this stage apparatus, since the adsorption position of the substrate is provided at a position that avoids the droplet arrangement region (that is, the thin film formation region), a uniform film without drying unevenness can be formed.

In the stage apparatus of the present invention, the mounting table may be formed on a substantially flat surface.
In this invention, since the structure which supports a board | substrate with a surface is employ | adopted, the structure of a mounting base becomes simple, and it can respond to this invention only by changing the suction position of the conventional stage apparatus.

In the stage apparatus according to the present invention, the mounting table is provided with a plurality of projecting support pins each having the suction hole formed at the tip thereof, and the substrate is supported by the plurality of support pins. can do.
In the present invention, since the back surface side of the substrate can be held in a state of being substantially lifted from the mounting table, the substrate can be heated uniformly from both the front surface side and the back surface side. Therefore, as compared with the configuration in which the substrate is supported on the surface as described above, the temperature distribution of the substrate is reduced and drying unevenness can be further reduced.

In the stage apparatus of the present invention, a gas ejection port for ejecting gas toward the back side of the substrate may be provided between the support pin and the support pin of the mounting table.
In the configuration in which the substrate is supported by the support pins as described above, the portion of the substrate that is not supported by the support pins bends, and film thickness unevenness may occur in the bent portion. In the present invention, since the portion not supported by the support pin is floated by the gas injection pressure, such film thickness unevenness does not occur.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.
FIG. 1 is a perspective view showing a schematic configuration of a droplet discharge device used in the thin film forming method of the present invention. In the thin film forming method of the present invention, a liquid material containing a functional material is disposed as droplets on the substrate 11, and the droplets are dried to form a film, thereby forming a thin film. In this embodiment, this droplet placement step (droplet discharge step) is performed using the droplet discharge device 100 of FIG.

  As shown in FIG. 1, a droplet discharge device 100 includes a droplet discharge head 10, an X-direction guide shaft 2 for driving the droplet discharge head 10 in the X direction, and an X-direction drive for rotating the X-direction guide shaft 2. The motor 3, the mounting table 4 for mounting the substrate 11, the Y-direction guide shaft 5 for driving the mounting table 4 in the Y direction, the Y-direction driving motor 6 for rotating the Y-direction guide shaft 5, and the cleaning mechanism unit 14. , And a control device 8 or the like for comprehensively controlling them. Each of the X direction guide shaft 2 and the Y direction guide shaft 5 is fixed on the base 7. In FIG. 1, the droplet discharge head 10 is arranged at a right angle to the traveling direction of the substrate 11, but the angle of the droplet discharging head 10 is adjusted so as to intersect the traveling direction of the substrate 11. It may be. In this way, the pitch between the nozzles can be adjusted by adjusting the angle of the droplet discharge head 10. Further, the distance between the substrate 11 and the nozzle surface may be arbitrarily adjusted.

  The droplet discharge head 10 discharges a liquid material made of a dispersion containing a functional material from a nozzle (discharge port), and is fixed to the X-direction guide shaft 2. Here, the functional material is a general term for materials that exhibit a predetermined function when formed into a film, and as such a function, an electric / electronic function (conductivity, insulation, piezoelectricity, pyroelectricity, Dielectric, etc.), optical functions (light selective absorption, reflectivity, polarization, light selective transmission, nonlinear optical properties, luminescence such as fluorescence or phosphorescence, photochromic properties, etc.), magnetic functions (hard magnetism, soft magnetism, etc.) , Non-magnetic, magnetic permeability, etc.), chemical function (adsorption, desorption, catalytic, water absorption, ion conductivity, redox, electrochemical properties, electrochromic, etc.), mechanical function (wear resistance) Etc.), thermal functions (heat transfer properties, heat insulation properties, infrared radiation properties, etc.), biological functions (biocompatibility, antithrombotic properties, etc.). In this embodiment, materials for display devices such as color filter pigments and organic EL materials are mainly assumed, but the present invention is not limited to this.

  The X direction drive motor 3 is a stepping motor or the like, and rotates the X direction guide shaft 2 when a drive pulse signal in the X axis direction is supplied from the control device 8. As the X-direction guide shaft 2 rotates, the droplet discharge head 10 moves in the X-axis direction with respect to the base 7.

  As the liquid ejection method, there are various known techniques such as a piezo method that ejects ink using a piezoelectric element, which is a piezoelectric element, and a bubble method that ejects a liquid material by bubbles generated by heating the liquid material. Applicable. Among these, the piezo method has an advantage that it does not affect the composition of the material because no heat is applied to the liquid material. In this example, the above piezo method is used from the viewpoint of the high degree of freedom in selecting the liquid material and the good controllability of the droplets.

The mounting table 4 is fixed to the Y-direction guide shaft 5, and Y-direction drive motors 6 and 16 are connected to the Y-direction guide shaft 5. The mounting table 4 is provided with a known suction mechanism such as a vacuum suction device so that the substrate 11 can be fixed in a state of being positioned at a predetermined position. The Y-direction drive motors 6 and 16 are stepping motors or the like, and rotate the Y-direction guide shaft 5 when a drive pulse signal in the Y-axis direction is supplied from the control device 8. The mounting table 4 moves in the Y-axis direction with respect to the base 7 by the rotation of the Y-direction guide shaft 5.
The cleaning mechanism 14 cleans the droplet discharge head 10 and prevents nozzle clogging and the like. The cleaning mechanism 14 is moved along the Y-direction guide shaft 5 by the Y-direction drive motor 16 during the cleaning.

  The droplet discharge device 100 configured as described above is installed in a drying device such as a thermal chamber, and the droplet placement step and the droplet drying step are performed while the substrate is held on the mounting table 4. It can be performed continuously. That is, in this embodiment, the droplet discharge device 100 also serves as the stage device of the present invention.

Next, a method for forming a thin film using the droplet discharge device 100 of this embodiment will be described.
In the droplet discharge device 100 of this embodiment, first, the substrate 11 is adsorbed and fixed to the mounting table 4 in a state where the substrate 11 is positioned at a predetermined position. Next, the substrate 11 and the droplet discharge head 10 are moved relative to each other via the X direction drive motor 3 and / or the Y direction drive motor 6 while discharging the liquid material from the droplet discharge head 10. A liquid material is placed on the substrate 11. The discharge amount of droplets from each nozzle of the droplet discharge head 10 is controlled by a voltage supplied from the control device 8 to the piezo element. The pitch of the droplets arranged on the substrate 11 is controlled by the speed of the relative movement and the ejection frequency from the droplet ejection head 10 (frequency of the driving voltage to the piezo element). Further, the position at which droplets are started on the substrate 11 is controlled by the relative movement direction, timing control of the start of droplet discharge from the droplet discharge head 10 during the relative movement, and the like. Next, while the substrate 11 is adsorbed on the mounting table 4, the substrate 11 is dried in a thermal chamber (drying device) to form a film of the liquid material disposed on the surface. It is assumed that the temperature in the thermal chamber is managed so that no temperature distribution occurs in the substrate 11.
Thus, a thin film pattern made of a functional material is formed on the substrate 11.

  By the way, in this embodiment, since a drying process is performed in a state where the substrate 11 is adsorbed to the mounting table 4, a temperature distribution is generated between the adsorbed portion and the non-adsorbed portion of the substrate 11, and drying is performed within the substrate surface. Unevenness may occur. Therefore, in the present embodiment, the adsorption position of the substrate 11 by the mounting table 4 is installed in a thin film formation region, that is, a region that does not overlap with the droplet arrangement region in a plane, and the substrate 11 is installed on the mounting table 4. In this case, the substrate 11 is accurately positioned so that the suction position of the substrate 11 and the thin film formation region do not overlap.

  2A and 2B are a schematic cross-sectional view (FIG. 2A) and a schematic plan view (FIG. 2B) showing an example of the configuration of the mounting table 4. FIG. In this example, a color filter, an organic EL light emitting layer, or the like is assumed as a film formed in the thin film formation region F, and the thin film formation region F is arranged in a matrix on the substrate 11 corresponding to the pixel arrangement. . The mounting table 4 of FIG. 2 has a substantially flat surface, and has a structure that supports the substrate 11 over the entire flat surface. On the surface of the mounting table 4, a large number of the above-described suction holes 4 a are arranged in a lattice pattern in a region corresponding to the non-pixel region, that is, the region where the thin film formation region F is not disposed.

  FIG. 3 is a diagram illustrating another configuration example of the mounting table 4. The mounting table of this example is different from the mounting table 4 of FIG. 2 in that a large number of protruding support pins 4b each having a suction hole 4a formed at the tip are provided on the surface of the mounting table 4, and the substrate 11 supports this. It is only a point that is held by suction at the tip of the pin 4b. The positional relationship between the suction hole 4a (that is, the position of the support pin 4b) and the thin film formation region F is the same as that in FIG. In this configuration, since the protrusion 4 is formed on the mounting table 4, the structure becomes complicated. However, since the back surface side of the substrate 11 can be held substantially floating from the mounting table 4, the substrate 11 can be held on both the front surface side and the back surface side. It becomes possible to heat uniformly from the side. Therefore, as compared with the configuration in which the substrate 11 is supported on the surface as shown in FIG. 2, the temperature distribution of the substrate 11 is reduced and drying unevenness can be further reduced. In this structure, the contact area between the support pins 4b and the substrate 11 is preferably as small as possible from the viewpoint of preventing the temperature distribution as much as possible in the substrate 11, but the contact area is reduced in this way. As a result, the substrate 11 may be displaced from the installation position in the droplet placement step (drawing step). For this reason, in this structure, in order to prevent such a shift | offset | difference, it is preferable to provide slip stoppers, such as rubber | gum, in the front-end | tip of the support pin 4b. In this case, a non-slip material having solvent resistance is used.

  FIG. 4 is a diagram showing still another configuration example of the mounting table 4. The mounting table of this example is different from the mounting table of FIG. 3 in that a gas jet port 4c is provided between the support pin 4b and the support pin 4b to jet gas toward the back side of the substrate 11. Only. In FIG. 4, the gas ejection port 4c is arranged at the center of each thin film formation region F, that is, at the center of the four support pins 4b arranged in a lattice pattern. As described above, in the configuration in which the substrate 11 is supported by the support pins 4b, a portion of the substrate that is not supported by the support pins 4b bends, and film thickness unevenness may occur in the bent portions. In this example, since the portion that is not supported by the support pins 4b is floated by the gas injection pressure, such film thickness unevenness does not occur. In this example, the temperature of the gas injected from the gas outlet 4c is preferably set to a temperature substantially equal to the drying temperature in the drying process (that is, the temperature in the thermal chamber). By doing so, the substrate 11 can be heated uniformly from both the front and back sides, and a thin film with less drying unevenness can be obtained.

  As described above, in this embodiment, since the adsorption position of the substrate 11 is provided at a position avoiding the thin film formation region F, a uniform film without drying unevenness can be formed.

Next, application examples of the thin film forming method of the present invention will be described. Here, an example in which the present invention is applied to a method for manufacturing a device such as a color filter or an organic EL device will be described.
First, an example in which the present invention is applied to a method for forming a film that is a constituent element of a color filter will be described with reference to FIG. FIG. 5 is a diagram showing a color filter formed on the substrate P, and FIG. 6 is a diagram showing a manufacturing procedure of the color filter. As shown in FIG. 5, in this example, a plurality of color filter regions 251 are formed in a matrix on a rectangular substrate P from the viewpoint of improving productivity. These color filter regions 251 can be used as color filters suitable for a liquid crystal display device by cutting the substrate P later. The color filter region 251 has a predetermined pattern, in this example, a conventionally known stripe type, of an R (red) liquid composition, a G (green) liquid composition, and a B (blue) liquid composition. Formed with. In addition to the stripe type, this formation pattern may be a mosaic type, a delta type, or a square type. And the surfactant mentioned above is added to each liquid composition of RGB.

In order to form such a color filter region 251, a bank 252 is first formed on one surface of a transparent substrate P as shown in FIG. The bank 252 is formed by exposing and developing after spin coating. The banks 252 are formed in a lattice shape in plan view, and ink is disposed inside the banks surrounded by the lattices. At this time, the bank 252 preferably has liquid repellency. The bank 252 preferably functions as a black matrix. Next, as shown in FIG. 6B, the liquid material composition droplets 254 are ejected from the droplet ejection head and land on the filter element 253. The amount of the liquid droplets 254 to be discharged is a sufficient amount considering the volume reduction of the liquid composition in the heating process. When all the filter elements 253 on the substrate P are filled with the droplets 254 in this way, the substrate P is heat-treated using a heater so as to reach a predetermined temperature (for example, about 70 ° C.). By this heat treatment, the solvent of the liquid composition evaporates and the volume of the liquid composition decreases. In the case where the current volume is intense, the droplet discharge process and the heating process are repeated until a sufficient film thickness is obtained for the color filter. By this treatment, the solvent contained in the liquid composition evaporates, and finally only the solid content contained in the liquid composition remains to form a film, and the color filter 255 as shown in FIG. Become. Next, in order to planarize the substrate P and protect the color filter 255, a protective film 256 is formed on the substrate P so as to cover the color filter 255 and the bank 252 as shown in FIG. In forming the protective film 256, a spin coating method, a roll coating method, a ripping method, or the like can be employed. However, as with the color filter 255, a droplet discharge method can also be used. Next, as shown in FIG. 6E, a transparent conductive film 257 is formed on the entire surface of the protective film 256 as necessary by a sputtering method, a vacuum evaporation method, or the like. Thereafter, the transparent conductive film 257 is patterned, and the pixel electrode 258 is patterned corresponding to the filter element 253 as shown in FIG. Note that this patterning is not necessary when a TFT (Thin Film Transistor) is used to drive the liquid crystal display panel.
As described above, the color filter is manufactured.

Next, an example in which the present invention is applied to a method for manufacturing an organic EL device will be described with reference to FIGS. 7 and 8 show only a single pixel for the sake of simplicity.
First, as shown in FIG. 7A, a substrate P having a drive circuit for driving an organic EL element is prepared. In FIG. 7A, reference numeral 643 denotes a TFT as a pixel driving element, 643A denotes a gate electrode, 643a denotes a source region, 643b denotes a drain region, 643c denotes a channel region, 720 denotes a gate insulating film, 730 denotes an interlayer insulating film, 736 , 738 are contact holes, 632 is a signal line, 633 is a common power supply line, 641 is a pixel electrode, and 740 is an interlayer insulating film. Here, a portion sandwiched between the signal line 632, the common power supply line 633, and further a scanning line (not shown) is a place where a hole injection layer and a light emitting layer described later are formed.

Next, a bank 650 is formed on the substrate P so as to surround the formation place. The bank 650 functions as a partition member, and is preferably formed of an insulating organic material such as polyimide. Further, it is preferable that the bank 650 has no affinity for the liquid composition discharged from the droplet discharge head. In order to express the non-affinity in the bank 650, for example, a method of treating the surface of the bank 650 with a fluorine compound or the like is employed. Examples of the fluorine compound include CF ₄ , SF ₅ , and CHF ₃ , and examples of the surface treatment include plasma treatment and UV irradiation treatment. Under such a configuration, a sufficiently high step 611 is formed between the formation site of the hole injection layer and the light emitting layer, that is, the application position of these forming materials and the surrounding bank 650. Is done. Next, as shown in FIG. 7B, with the upper surface of the substrate P facing upward, the liquid composition (droplet) 614A containing the hole injection layer forming material is transferred to the bank 650 by the droplet discharge head. The coating is selectively applied in a coating position surrounded by, that is, in the bank 650. Next, as shown in FIG. 7C, the solvent of the liquid composition 614A is evaporated by heating or light irradiation, so that a solid hole injection layer 640A is formed on the pixel electrode 641.

Next, as shown in FIG. 8A, a liquid composition 614B containing a light emitting layer forming material (light emitting material) is placed in the bank 650 from the droplet discharge head with the upper surface of the substrate P facing upward. Is selectively applied on the positive hole injection layer 640A. When the liquid composition (droplet) 614B containing the light emitting layer forming material is discharged from the droplet discharge head, the liquid composition 614B is applied onto the hole injection layer 640A in the bank 650. Here, the formation of the light emitting layer by discharging the liquid composition 614B includes a liquid composition containing a light emitting layer forming material that emits red colored light and a light emitting layer forming material that emits green colored light. The liquid composition and the liquid composition containing the light emitting layer forming material that emits blue colored light are discharged and applied to the corresponding pixels. Note that the pixels corresponding to each color are determined in advance so that they are regularly arranged. When the liquid composition 614B containing the light emitting layer forming material of each color is discharged and applied in this manner, the solvent in the liquid composition 614B is evaporated, thereby forming a hole layer as shown in FIG. A solid light emitting layer 640B is formed on the injection layer 640A, whereby a light emitting portion 640 composed of the hole layer injection layer 640A and the light emitting layer 640B is obtained. Thereafter, as shown in FIG. 8C, the reflective electrodes 654 are formed on the entire surface of the transparent substrate P or in a stripe shape.
Thus, the organic EL element is manufactured.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

1 is a schematic perspective view of a droplet discharge device that is an example of a stage device of the present invention. The schematic diagram which shows the structure of the mounting base with which a droplet discharge apparatus is equipped. The schematic diagram which shows the other structural example of a mounting base. The schematic diagram which shows the further another structural example of a mounting base. FIG. 3 is a schematic diagram of a color filter that is an example of a device of the present invention. Process drawing for demonstrating the manufacturing method of a color filter. Process drawing for demonstrating the manufacturing method of the organic electroluminescent apparatus which is an example of a device. Process drawing following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 ... Mounting stand, 4a ... Adsorption hole, 4b ... Support pin, 4c ... Gas ejection port, 10 ... Droplet discharge head, 11, P ... Substrate, 100 ... Droplet discharge device (stage device), 254, 614A, 614B ... droplet, F ... thin film formation region

Claims (2)

A method of forming a thin film including a step of disposing a liquid material containing a functional material as droplets on a substrate and drying the droplets into a film,
The droplet drying step is performed in a state where the substrate is held on a stage device by adsorbing a region other than the droplet arrangement region of the substrate .
The stage device includes a mounting table having a flat surface .
A plurality of suction holes for sucking the substrate are provided on the flat surface of the mounting table,
The method of forming a thin film, wherein the droplet drying step is performed in a state where the substrate is brought into contact with the flat surface of the mounting table and the substrate is sucked by the suction hole. When the liquid material containing the functional material is disposed on the substrate as droplets, and the droplets disposed on the substrate are dried in the thin film forming step including the step of drying the droplets to form a film. A stage device used for adsorbing and holding the substrate;
Comprising a mounting table in which a suction hole for sucking the substrate is formed, the suction hole is disposed in a region other than the thin film formation region of the substrate ;
The surface of the mounting table is formed flat ,
A stage apparatus configured to bring the substrate into contact with a flat surface of the mounting table and suck the substrate through the suction hole .

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