JP2009288383A - Manufacturing method and manufacturing apparatus for functional element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a functional element by which the shape of a functional layer is sufficiently made flat in the functional element having the functional layer separated by a partition wall on a substrate. <P>SOLUTION: After being coated with a liquid material by an inkjet method and charged to a drying device, the substrate is dried by supplying a solvent vapor from a supply port 7 to hold the inside of the device to a solvent atmosphere and selectively heating the partition wall part by an infrared radiation device 16 provided on the upper position of a substrate stage 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for manufacturing a functional element having a functional layer patterned on a substrate partitioned by a partition wall.

  In recent years, the competition for manufacturing high-definition and beautiful displays has intensified. Among them, organic electroluminescent elements (hereinafter referred to as organic EL elements), color filters, and the like are attracting attention as satisfying the demand for higher definition and thinner layers. These organic EL elements and color filters require a fine patterning technique.

  In recent years, the ink jet method has attracted attention in the production of elements that require fine patterning (hereinafter referred to as functional elements) such as organic EL elements and color filters. As a typical method other than the ink jet method, there is a photolithography method. In the photolithography method, after forming a coating film on the entire substrate, fine patterning is performed by removing unnecessary portions. This method is essential for photolithography, leading to waste of materials and an increase in the number of processes. On the other hand, the ink jet method does not generate such waste, and is advantageous from the viewpoint of reducing the environmental load, drastically reducing costs, and shortening the forming process.

  As a method for manufacturing a substrate for performing fine patterning using an ink jet method, for example, methods described in Patent Documents 1 to 3 below have been proposed. In Patent Documents 1 to 3, as a method for producing a color filter substrate using an ink jet method, black color containing a habit ink agent such as a fluorine-containing compound is used to prevent a defect that colored inks of different colors are mixed. It is described that a resin layer is formed by a photolithography method or the like to form a black matrix.

  In many cases, the shape of the functional layer formed by the method of discharging and drying the coating liquid into the partition walls is not flat but convex or concave. The reason is that the shape of the discharged coating liquid and the drying speed are not uniform within the partition wall. Whether it is a convex shape or a concave shape varies depending on the material properties of the functional element and the properties of the substrate. When the film thickness difference between the central part and the end part of the droplet is large, a problem caused by the difference occurs. For example, in the colored layer of the color filter, there is an effect that color unevenness due to a film thickness difference or contrast performance is deteriorated. Even in the organic EL element, problems such as uneven light emission and a decrease in light emission efficiency occur.

  In Patent Document 4, a technique for improving flatness is disclosed as a technique for improving flatness in order to manufacture a functional element having higher flatness that does not cause inconvenience in function with higher definition. Has been.

  However, the method of Patent Document 4 has a problem that there is a step between the partition wall and the functional layer, although it is flat as long as it is limited to the dried and cured functional layer. In the color filter, a step is generated between the cured colored resin composition and the black matrix forming the partition wall, and there is a possibility that color unevenness due to the step is generated.

  In Patent Document 5, it is proposed to improve the flatness of the shape after drying by controlling the volatilization rate of the solvent by blowing air. However, in the control by blowing, unevenness due to the difficulty in controlling the blowing itself occurs, so that it is difficult to use in a product that requires high film thickness accuracy.

JP-A-6-347637 JP-A-7-35915 JP-A-6-35917 JP2007-256313 JP2007-000867

  As described above, in the functional element in which the functional layer is finely patterned, the dried coating film in the partition walls needs to have sufficient flatness. Therefore, an object of the present invention is to provide a method and apparatus for manufacturing a functional element having sufficient flatness.

  The invention according to claim 1 has a functionality in which a coating liquid containing a functional layer forming material is applied to an opening of a partition wall formed on a substrate, and the coating liquid is dried and solidified to form a functional layer. A method for producing a functional element, wherein the functional layer is dried at a higher rate in the vicinity of the partition wall than in the central portion. The invention described in claim 2 is a function for applying a coating liquid containing a functional layer forming material to an opening of a partition wall formed on a substrate, and drying and solidifying the coating liquid to form a functional layer. A method for manufacturing a functional element, wherein a partition wall portion is selectively heated and dried.

  The present invention is characterized in that the distribution of the drying rate on the functional layer is controlled so that the flow from the central part to the peripheral part is sufficiently performed. Thereby, the film thickness difference between the central portion and the end portion of the functional layer is reduced, and the flatness of the functional layer is improved.

  The drying phenomenon of the droplet shows complicated behavior depending on the state of the air layer and the concentration distribution of the droplet in the partition wall. While the flow due to the surface tension is sufficiently occurring, the flatness is improved as the drying proceeds. However, when the drying proceeds uniformly, the flow from the central part to the end part stops at the beginning or middle of the drying. As a result, the flatness is lost from the dried shape. By providing the drying speed distribution, the flow can be maintained until the end of drying.

  The invention described in claim 3 is the method for manufacturing a functional element according to claim 1 or 2, wherein the functional layer is dried in a solvent atmosphere.

  In addition to the effects as described above, the drying speed is controlled in order to allow sufficient flow from the central part of the functional layer to the peripheral part in the vicinity of the partition wall. Thereby, the film thickness difference between the central portion and the end portion of the functional layer is reduced, and the flatness of the functional layer is improved. In general, when the initial shape is a convex shape, the coating liquid is dried first from the central portion of the functional layer to the peripheral portion in the vicinity of the partition wall. When the drying time is short, this flow is not performed until the end, and the convex shape is solidified. By drying the functional layer under a solvent atmosphere and lengthening the drying time, the solute flow from the central portion of the functional layer to the peripheral portion near the partition can be continued for a long time. Thereby, the film thickness difference between the central portion and the end portion of the functional layer is reduced, and the flatness of the functional layer is improved.

  The invention according to claim 4 is the method for producing a functional element according to any one of claims 1 to 3, wherein the functional element is a color filter.

  Since the invention described in any one of claims 1 to 3 improves the flatness of the functional layer, it is desirable that the functional layer is a color filter. This is because in the color filter, the improvement in flatness leads to improvement in contrast performance and cost reduction, and the effect is high.

  The invention according to claim 5 is a coating means for applying a coating liquid containing a functional layer forming material to an opening of a partition wall formed on a substrate, and a drying mechanism for drying the applied coating liquid. The drying mechanism includes a drying zone having drying means for selectively heating the partition wall portion, an air supply means for supplying solvent vapor into the drying zone, and exhausting the solvent vapor in the drying zone. A functional element manufacturing apparatus including a solvent atmosphere control mechanism that controls a solvent atmosphere with an exhaust unit.

  According to a sixth aspect of the present invention, in the functional element manufacturing apparatus according to the fifth aspect of the present invention, the drying means for selectively heating the partition wall portion is an infrared radiation device installed facing the stage on which the substrate is installed. It is the manufacturing apparatus of the functional element characterized by these.

  A seventh aspect of the present invention is the functional element manufacturing apparatus according to the fifth or sixth aspect, wherein the coating means is an ink jet apparatus.

  The application method of the functional layer forming coating liquid is preferably an ink jet method. The droplets ejected into the partition walls by the ink jet method are likely to form convex shapes with low flatness and a large film thickness difference after drying, and the present invention has an effect of flattening the convex shapes of these functional layers. It is.

  The invention according to claim 8 is the functional device manufacturing apparatus according to any one of claims 5 to 7, wherein the substrate is a color filter substrate.

  According to the present invention, a functional element that is flat in the drying process can be manufactured. As a result, it is possible to manufacture a color filter with improved contrast performance and reduced cost.

<Method for producing functional element>
As shown in FIG. 1, a region partitioned by a partition 1 in a lattice shape or a stripe shape is called a cell. In the method for producing a functional element of the present invention, a coating liquid containing a colored layer material is applied and filled in the cell. Examples of the coating means include a pigment dispersion method, a dye method, an electrodeposition method, a printing method, a transfer method, and an ink jet method.

  The coating means for applying the coating liquid in the present invention is not limited as long as it is a forming method that can fill the partition wall by patterning the coating liquid, but an inkjet method is more preferable. This is because the color filter applied by the ink jet method is expected to reduce the cost by efficiently using the coating liquid and shortening the forming process.

  FIG. 2 shows a cross-sectional view taken along the plane A-A 'of FIG. Partition walls are formed on the substrate, functional elements are filled between the partition walls, and a functional layer is formed. In the case of a color filter, the functional layer is a colored layer and is generally a pixel pattern of three primary colors, R (red), G (Green), and B (Blue). In the case of an organic EL element, it is a light emitting layer including a hole transport layer, an electron transport layer and the like.

  The partition wall can be formed by a general method such as a photolithography method using a photosensitive resin or various printing methods. Also, a black matrix can be formed on the substrate to improve contrast. The black matrix can be formed as a partition, or a part of the partition or a lower layer of the partition.

  Next, the liquid functional layer formed in the cell is dried and formed by firing or the like as necessary. The method for controlling the drying speed is not particularly limited, but it is desirable to control the gas phase part by blowing, sealing, or reducing pressure.

  A phenomenon known as a coffee stain phenomenon is known as a drying phenomenon of droplets. This phenomenon is a phenomenon in which the concentration at the end portion becomes higher than the central portion as evaporation proceeds, and the end portion rises after drying. The inventors quickly dry the vicinity of the partition wall to increase the concentration at the end portion to cause the above phenomenon, and the distribution of the drying speed is different between the region in the vicinity of the partition wall and the region in the central portion. It was found that the cell edge portion of the cell can be flattened by solidifying it first.

  As a method for selectively controlling the drying speed in the vicinity of the partition wall, a method in which the partition wall is partially heated as will be described later. As a method for heating the partition wall part, a method in which the partition wall part is made of a light absorbing material and heated by light absorption is desirable.

  In general, when the initial shape of the droplet drying is a convex shape, the flow from the central portion of the functional layer to the peripheral portion in the vicinity of the partition wall first occurs. When the drying time is short, this flow is not performed until the end, and the convex shape is solidified. By drying the functional layer under a solvent atmosphere and lengthening the drying time, the solute flow from the central portion of the functional layer to the peripheral portion near the partition can be continued for a long time. Thereby, the film thickness difference between the central portion and the end portion of the functional layer is reduced, and the flatness of the functional layer is improved.

  Droplet drying generally exhibits a complicated drying behavior depending on the concentration state of the droplet and the state of the air layer. In the initial stage of drying, the flatness is gradually improved by the flow of the liquid due to the effect of the surface tension. If the drying speed is too high, the improvement in flatness stops halfway and the flatness is lost.

  The inventors have found that the functional layer can be dried under a solvent atmosphere and the liquid flow can be sufficiently performed by suppressing the drying speed, thereby improving the flatness.

  In addition, even when sufficient drying time is taken, as the drying proceeds, the liquid does not flow sufficiently, and the non-flattening effect due to the complicated drying behavior exceeds the flattening effect due to the liquid flow. The flatness in the functional layer is lost. In many cases, it rises in a convex shape at the center. Therefore, as described above, the above-mentioned coffee stain phenomenon is effectively utilized by providing a distribution in the drying rate in the region near the partition and the region in the central part, and making the drying rate of the partition part higher than that in the central part. In addition, it is possible to form a flat functional layer by solidifying the coating liquid while ensuring fluidity by drying in a solvent atmosphere.

  The functional element of the present invention is not particularly limited as long as flatness is required, but a color filter is particularly desirable. This is because the color filter is highly likely to cause color unevenness and deterioration of the contrast ratio due to the difference in film thickness of the functional elements, and high definition can be achieved by obtaining a flat shape. Further, the partition walls of the color filter substrate are often made of a black matrix, that is, black, and therefore, it is easy to promote a temperature rise by infrared radiation.

<Functional element manufacturing apparatus>
Next, the functional device manufacturing apparatus of the present invention will be described. The functional device manufacturing apparatus of the present invention includes a coating unit that applies a coating liquid by a discharge method, a drying unit that dries the coating liquid applied by the coating unit while controlling a solvent atmosphere, and a partition wall portion. It has the structure which has a drying means combined with drying while heating. Hereinafter, each means of the manufacturing apparatus of the present invention will be described.

1. Coating device As a coating means in the present invention, a coating device capable of patterning a functional layer by applying a coating liquid containing a functional material to the opening of the partition wall, for example, a functional layer forming coating There is no particular limitation as long as it is a discharge device or the like that discharges and applies the working liquid. Among these, an inkjet device is preferable.

2. 2. Drying Device 2.1 Solvent Atmosphere Control Mechanism The drying device of the production apparatus of the present invention has a drying means for drying while controlling the solvent atmosphere. As an example of the drying apparatus, as shown in FIG. 3, a substrate drying unit in the apparatus is provided with a supply / exhaust port, and other than the supply / exhaust port is sealed, and control is performed to adjust the solvent atmosphere using an air flow. An apparatus having a method is mentioned. Other than this example, there is no particular limitation as long as the structure can suppress the evaporation of the solvent. The solvent vapor used is preferably the solvent used in the coating, but is not particularly limited as long as it does not reduce the performance of the functional element.

2.2 Infrared Radiation Device The drying device of the production apparatus of the present invention has a drying means for selectively heating the partition wall portion in addition to the drying mechanism. As an example of the structure, as shown in FIG. 4, for example, when the partition wall portion of the substrate is composed of a black matrix (black), a far infrared heating device (IR heater) is opposed to the substrate stage at the upper position of the substrate stage. A structure in which light is absorbed by the partition wall and selectively heated by performing infrared radiation during drying. Even if it is except this example, if it is a heating method which can selectively heat a partition part, it will not specifically limit. By heating the partition wall portion and accelerating the evaporation of the solvent near the partition wall, the functional layer can be flattened.

2.3 Heating Device In the present invention, it is desirable to use a manufacturing device in which a heating device is combined with the above device. This is to obtain an effect of facilitating flow by increasing the temperature by heating and decreasing the viscosity of the functional layer. When the drying speed becomes too fast due to heating, the problem is solved by suppressing the drying speed by the solvent atmosphere control device. Such a heating device is not particularly limited as long as it can easily raise the temperature of the functional layer forming coating solution, and can be dried and solidified. Therefore, a commonly used heating device or the like can be used, and specific examples include an oven and a hot plate. Among these, a hot plate is preferable as a heating device. This is because the hot plate is a device that conducts heat directly from the lower side of the substrate and dries it, so that it is excellent in thermal efficiency and has little heating unevenness.

Example 1
Numerical analysis was performed on the case where the functional layer was dried with an infrared radiation device, and the shape after drying was calculated. The calculation conditions were such that the distance between the partition walls on the substrate was 360 μm, the partition wall height was 2 μm, and droplets were ejected at about 1000 pl. The properties of the droplets are a viscosity of 10 mPa · s, a surface tension of 25 mN / m, and a boiling point of 220 ° C. In the case of 80 ° C., the average initial reduction rate of the average film thickness of the coated product is about 1 × 10 ⁻⁷ m / s. Here, the temperature of the central portion of the functional layer was set to 70 ° C., the temperature of the partition wall portion was set to 80 ° C., and a temperature difference was given. The cross-sectional shape result after drying is shown in FIG. As a method for evaluating the flatness of the functional layer, the thickness A (x) of the functional layer (x is a positional variable on the substrate), the maximum value of the film thickness is A1, the minimum value is A2, and the height of the partition wall is D. As described above, the conditions (1) and (2) were evaluated.

  In Example 1, A1 = 1.9 μm, A2 = 1.4 μm, D1 = 2.0 μm, and A (x) occupied 3/4 or more of the entire shape. Therefore, the condition (2) was satisfied.

(Comparative Example 1)
Under the calculation conditions of Example 1, the temperature of the functional layer was set at 80 ° C. to perform numerical analysis. The cross-sectional shape result after drying is shown in FIG. A1 = 2.1 μm, A2 = 1.3 μm, D1 = 2.0 μm, and the shape did not satisfy the conditions (1) and (2).

(Example 2)
In addition to the temperature distribution conditions as in Example 1, numerical analysis was performed for the case where drying was performed while controlling the solvent atmosphere, and the shape after drying was calculated. The calculation conditions were such that the distance between the partition walls on the substrate was 360 μm, the partition wall height was 2 μm, and droplets were ejected at about 200 pl. The properties of the droplets are a viscosity of 10 mPa · s, a surface tension of 25 mN / m, and a boiling point of 220 ° C. Here, the temperature of the central portion of the functional layer was set to 70 ° C., the temperature of the partition wall portion was set to 80 ° C., and a temperature difference was given. In addition, the analysis was performed with the average initial decrease rate of the average film thickness of the coated material as small as 4 × 10 ⁻⁸ m / s. The result of the cross-sectional shape of the central part of the droplet after drying is shown in FIG. A1 = 2.0 μm, A2 = 1.6 μm, and D1 = 2.0 μm, which satisfied both the conditions (1) and (2).

  The above embodiments and examples are described as examples for facilitating the understanding of the present invention, and the present invention is limited to the specific configurations and arrangements described in this specification or the accompanying drawings. It is not limited. The specific structures, means, methods, and devices described herein can be replaced with many others known in the art without departing from the spirit and scope of the present invention.

(Evaluation of flatness of functional layer)
In the present invention, the maximum height of the film thickness shape is A1, the minimum height of the film thickness shape is A2, the ideal film thickness of the functional layer is D,
| D-A1 | ≦ D / 10 (partition wall height ± 10% region)
While satisfying
A1- A2 ≦ D / 5
Satisfies the following condition (1), or
| D-A1 | ≦ D / 10
At the same time, when the functional layer thickness at a certain position x is A (x),
| D-A (x) | ≦ D / 10
When the region within the range satisfies the condition (2) that occupies 3/4 of the functional layer inside the partition, the functional layer was evaluated as being flat. In each example, the partition wall height was used as D.

Substrate before functional layer formation Cross section of functional element (convex shape) Cross section of drying equipment Sectional view of a drying device equipped with an infrared radiation device Shape after functional layer drying of Example 1 Shape after drying functional layer of Comparative Example 1 Shape after functional layer drying of Example 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Partition 2 Cell 3 Functional layer 4 Substrate 7 Solvent vapor supply port 8 Solvent vapor exhaust port 9 Substrate input port 10 Substrate discharge port 11 Substrate stage 12 Substrate 13 Bulkhead 14 Substrate transport direction 15 Black matrix 16 Infrared radiation device

Claims (8)

A coating liquid containing a functional layer forming material is applied to an opening of a partition formed on a substrate, and the functional liquid is produced by drying and solidifying the coating liquid to form a functional layer,
A method for producing a functional element, wherein the drying speed of the functional layer is higher in the vicinity of the partition wall than in the central portion. A coating liquid containing a functional layer forming material is applied to an opening of a partition formed on a substrate, and the functional liquid is produced by drying and solidifying the coating liquid to form a functional layer,
A method for producing a functional element, wherein the partition wall portion is selectively heated and dried.   The method for producing a functional element according to claim 1, wherein the functional layer is dried in a solvent atmosphere.   The method of manufacturing a functional element according to claim 1, wherein the functional element is a color filter. A coating means for coating the coating liquid containing the functional layer forming material in the opening of the partition formed on the substrate, and a drying mechanism for drying the coated coating liquid,
The drying mechanism includes a drying zone having a drying means for selectively heating the partition wall portion;
An apparatus for manufacturing a functional element, comprising: an air supply unit that supplies solvent vapor into a drying zone; and a solvent atmosphere control mechanism that controls a solvent atmosphere by an exhaust unit that exhausts the solvent vapor in the drying zone.   6. The functional element manufacturing apparatus according to claim 5, wherein the drying means for selectively heating the partition wall portion is an infrared radiation device installed facing a stage on which a substrate is installed. Device manufacturing equipment.   7. The functional element manufacturing apparatus according to claim 5, wherein the coating means is an ink jet apparatus.   8. The functional element manufacturing apparatus according to claim 5, wherein the substrate is a color filter substrate.