JP2005349250A - Partial formation method for thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a partial formation method for a thin film solving a problem that a correction ink overflows from a recessed part, i.e., a correction portion and correction cannot be performed in correction of a thin film by an ink jet and previously perform liquid-repellent treatment of the whole surface of a substrate in order to suppress overflowing from the recessed part. <P>SOLUTION: In the method, the thin film is selectively formed by delivering and filling an ink containing a material for forming the thin film from an ink jet head 1 to the recessed part 7 after a foreign matter 6 on an insulation layer 5 such as TFT liquid crystal panel is removed. In the method, a self-liquid repellent ink having a contact angle of 15° or higher relative to the ink to be coated of the thin film formed by the ink to be coated is used and the the recessed part is coated with the ink by ink jet to form a coating part 8 of a first drop so as to over flow in the recessed part 7. Thereafter, the recessed part is coated once or several times with the ink corresponding to required film thickness by the ink jet to form a coat coating part 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for partially forming a thin film, and more particularly to a technique for forming a partial thin film that can be applied to correction of a minute defect partially generated in a thin film in a thin film process such as a TFT liquid crystal panel. It is.

  In a thin film process such as a TFT liquid crystal panel, if a defect or the like partially occurs in the formed thin film, it leads to a panel failure. It is possible to detect these defects and correct them to make them non-defective. Conventionally, as in Patent Document 1, the defect area is removed by laser light irradiation, the material is ejected by an inkjet head, and coating is performed. Thus, a method of correcting a defect has been proposed.

  However, since inks used for ink jet have solid components dissolved in a solvent, the amount of ink containing a desired amount of solids is usually larger than the amount of solids, and correction is defective. Ink containing a material that is the same as or similar to the thin film material is often used, and the affinity between the ink and the thin film is high. Therefore, in the method according to Patent Document 1, the correction ink does not stay in the recesses and overflows, and the desired ink is used. The concave part could not be corrected in the shape.

In order to suppress this overflow, Patent Document 2 proposes a method in which a liquid repellent portion is formed in advance around a droplet application portion using a photolithography technique to control the spread of the droplet.
Patent Document 3 proposes a method in which the entire surface is subjected to a lyophobic treatment in advance, and only the coated portion is subjected to a lyophilic treatment with an acid or alkali solution.
Furthermore, Patent Document 4 proposes a method of controlling the spread of droplets by applying droplets to a preheated substrate.
Japanese Patent Laid-Open No. 11-271752 JP 2000-193816 A JP 2000-33698 A Japanese Patent Laid-Open No. 2003-133682

  However, in the methods described in Patent Documents 2 and 3, even when partial application is performed, it is necessary to perform a liquid repellency treatment on the entire surface of the substrate in advance, especially when used for the purpose of correcting defective portions. However, it is necessary to perform an extra step in preparation for an event that is uncertain whether or not it will occur, and this causes a problem of increasing costs. Furthermore, this liquid repellent part is an unnecessary part for device operation. When the liquid repellent part adversely affects the subsequent process, it is necessary to process the entire substrate again and remove the liquid repellent part. Furthermore, there is a problem that the process becomes complicated. In addition, if the method described in Patent Document 4 is used, prior processing on the entire substrate is not necessary, but it is necessary to heat the substrate or stage in a process that requires high accuracy. It is not realistic to heat a large substrate.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research, and as a result, using an ink jet, an ink containing a material for forming a thin film is applied, and in the step of selectively forming a thin film in a recess, the application is performed. Using an ink having a contact angle of 15 ° or more with respect to the applied ink of the thin film formed by the ink (hereinafter referred to as self-repellent ink), first, the ink is applied by ink jet so as to overflow into the concave portion, and then required. It has been found that a thin film can be stably and partially formed by applying ink corresponding to the film thickness in one or several times by inkjet.

  The invention according to claim 1 is a thin film formed by applying the ink in the method for partially forming a thin film by applying an ink containing a material for forming the thin film by using an ink jet and selectively forming the thin film in the recess. Using the ink having a contact angle of 15 ° or more with respect to the ink to be applied, and applying the ink corresponding to the required film thickness once or several times by the ink jet so as to overflow the recess. It is characterized by including the process of apply | coating in steps.

  A second aspect of the invention is the method of partially forming a thin film according to the first aspect, comprising the step of drying the ink at least in the overflowed portion after applying the ink so as to overflow the recess. To do.

  According to a third aspect of the present invention, in the method for partially forming a thin film according to the first or second aspect, before applying the ink so as to overflow the concave portion, at least the lyophilic property to the ink applied around the concave portion. And a processing step for improving the process.

  According to a fourth aspect of the present invention, in the method for partially forming a thin film according to the third aspect, the treatment step for improving the lyophilic property is any one of UV irradiation, solvent coating, surface roughening, surfactant coating, and cleaning. The process is performed.

  According to a fifth aspect of the present invention, in the method for partially forming a thin film according to any one of the first to fourth aspects, the ink is a thin film formed of the ink by adding a fluorine-based or silane-based surfactant. The contact angle with respect to the ink is 15 ° or more.

  The first effect of the present invention is to apply an ink containing a material for forming a thin film by using an ink jet and selectively apply the thin film formed by the applied ink in the step of selectively forming the thin film in the recess. Using ink having a contact angle of 15 ° or more, first, the ink is applied by ink jet so as to overflow the concave portion, and then the ink corresponding to the required film thickness is applied once or several times by ink jet, so that the ink overflows. The ink applied in this manner can control the liquid repellency of the portion where the thin film is to be formed, and can control the spread of the droplets to form the thin film at a desired site.

  The second effect of the present invention is that after the ink is applied so as to overflow into the recess, at least the ink in the overflowing portion is dried, so that the liquid repellency of the overflowing portion is more stable and the spread of the droplets is controlled. Thus, a thin film can be formed at a desired site.

  The third effect of the present invention is that before the ink is applied so as to overflow into the recess, a process for improving the lyophilicity to the applied ink at least around the recess is performed, so that the droplet can easily overflow. As a result, the spread of the droplets can be controlled to form a thin film at a desired site, and the film thickness formed at the overflowed portion can be controlled to be thinner.

  The fourth effect of the present invention is that the treatment for improving the lyophilic property before applying ink so as to overflow into the recesses is performed by any one of UV irradiation, solvent coating, surface roughening, surfactant coating, and washing. Thus, lyophilicity can be easily improved.

  The fifth effect of the present invention is that by adding a fluorine-based or silane-based surfactant, an ink having a contact angle of 15 ° or more with respect to the applied ink of the thin film formed by the applied ink can be easily obtained. it can.

  The method for partially forming a thin film according to the present invention starts with trimming with a laser or the like when a portion where a thin film is to be partially formed is not concave. When the concave shape is caused by peeling of the film or the like, the concave shape may be used as it is, or the concave portion may be formed and trimmed by a laser or the like. Next, using an ink jet head, self-repellent ink is ejected and applied so as to overflow the recess (hereinafter referred to as application of the first droplet). At this time, it is important to apply the self-liquid-repellent ink so as to overflow from the entire periphery of the recess. This is because the purpose of the application of the first droplet is to prevent the ink from overflowing from the concave portion when the ink is applied to obtain a desired film thickness (hereinafter referred to as coat application). This is because the entire outer periphery of the concave portion needs to be treated with the first droplet.

  In the coating application, the amount of droplets is adjusted so that the desired film thickness is obtained, but when the solid content in the ink is small and the coating amount is larger than the film formation volume, it is several times. It is also possible to apply the liquid droplets while controlling the volume of the applied liquid droplets by drying. Furthermore, if the wettability of the ink and the outer periphery of the concave part forming the film is poor and it is difficult to stably overflow the first droplet, by performing a treatment to improve the wettability on the outer periphery of the concave part, As a result, the first droplet can be stably overflowed, and as a result, the coating can be stably applied.

Hereinafter, based on an Example, this invention is demonstrated in detail.
7A and 7B are diagrams schematically illustrating a structure of a pixel of the TFT liquid crystal panel, in which FIG. 7A is a plan view and FIG. 7B is a cross-sectional view taken along line XX in FIG.
Transparent electrodes 13 and 13 are formed in a wiring pattern composed of gate wiring 10 and source wiring 11 arranged in a lattice pattern on upper and lower glass substrates 4 and 4, and between transparent electrodes 13 and 13 on the opposing glass substrate. The liquid crystal 14 is sealed, and a voltage is applied between the transparent electrodes 13 and 13 to change the orientation of the liquid crystal molecules, thereby controlling the amount of transmitted light and performing display. Here, in order to maintain display quality, it is necessary to control the gap between the upper and lower transparent electrodes 13 and 13 with high accuracy. That is, when a defect occurs in the insulating layer 5 below the transparent electrode 13, it is important to remove the insulating film in that portion and then apply the insulating film again to flatten the insulating film. Become.
Hereinafter, the present invention will be described by taking the correction process as an example.

FIG. 8 is a cross-sectional view schematically showing a substrate having a foreign substance defect, and FIG. 9 is a diagram showing a method of removing the foreign substance defect shown in FIG.
FIG. 8 shows a substrate in which the upper surface of the insulating layer 5 becomes a convex defect due to the inclusion of foreign matter 6 in the insulating layer 5 in the glass substrate 4 formed up to the insulating layer 5 below the transparent electrode 13. As shown in FIG. 9A, the defect is corrected by removing the insulating layer 5 in the region including the foreign matter 6 by ultraviolet laser irradiation using the ultraviolet laser device 3 (FIG. 9B), and then forming the recess 7. (FIG. 9C). In this embodiment, the foreign matter 6 is removed by ultraviolet laser irradiation. However, this does not limit the present invention, and other removal methods may be used. Furthermore, although the present embodiment has been described using the case relating to the defect of the foreign material 6 involved, it is needless to say that it is also effective for the peeling defect of the insulating layer 5. Part removal can be omitted.

FIG. 10 is a diagram showing a correction process in the order of steps in the method for partially forming a thin film of the present invention.
As described with reference to FIG. 9, the insulating layer 5 (FIG. 10A) in the region including the foreign matter 6 is removed by the ultraviolet (UV) laser irradiation using the ultraviolet laser device 3 to the recess 7 having a depth of 100 μm. On the other hand (FIG. 10B), first, four droplets of self-repellent ink were discharged using the inkjet head 1 so as to overflow the concave portion 7, thereby forming the first droplet application portion 8 (FIG. 10C). )). Thereafter, the overflow portion was completely dried by infrared irradiation using the infrared lamp 2 (FIG. 10D). Next, with respect to the concave portion 7 in which the first-drop application unit 8 has been completed, while applying 5 drops of coat application unit 9 at one time, 4 times while performing intermediate drying by infrared irradiation by the infrared lamp 2 4 The concave portion 7 was embedded repeatedly (FIG. 10E).

FIG. 1 is a diagram showing a measurement result of a sectional shape of a recess after defect correction using the method for partially forming a thin film according to Example 1 of the present invention. FIG. 2 is an ink having no self-liquid repellency as a comparative example. It is a figure which shows the recessed part cross-sectional shape measurement result after performing defect correction by the same process using FIG.
As is clear from the comparison between FIG. 1 and FIG. 2, when ink having self-repellent properties is used, the liquid repellent portion formed by applying the first droplet suppresses the overflow of the ink during coating application. It can be seen that the recesses are effectively embedded.
However, in the case of an ink that does not have self-liquid repellency, the ink at the time of coating application overflows from the recess and cannot be embedded effectively.
In this embodiment, the infrared lamp 2 is used for promoting drying, but this does not limit the present invention at all, and it is effective even if other drying means or natural drying is performed. Needless to say. Further, the present invention is not limited with respect to the initial drop application amount, the coat application amount, and the number of applications, and may be determined as appropriate.

  Next, the method for partially forming the thin film of Example 2 uses a substrate having a different processing method from that of Example 1, and makes the insulating film less lyophilic with respect to the ink than in Example 1. On the other hand, a correction was made. In the case of a substrate that is weakly lyophilic with respect to ink, it becomes difficult to uniformly overflow the initial droplets. Therefore, the surface of the concave frame is preliminarily roughened with a UV laser at a portion corresponding to the portion where the initial droplets overflow. Irradiation with power was performed to improve the lyophilicity of the frame portion with respect to the ink. By applying the same method as in Example 1 to the substrate, initial droplet application and coat application were performed. As a comparative example, even when the treatment for improving lyophilicity was not performed, the first drop was applied and the coat was applied.

As a result, in the case where the treatment for improving the lyophilic property was performed, the initial droplets were allowed to overflow uniformly from the entire periphery of the concave frame portion, and the concave portions could be embedded by subsequent coating application. In addition, the film formed by the overflow of the first droplet could be formed thin.
However, when the treatment for improving the lyophilic property is not performed, first, when applying the first drop, the first drop cannot be uniformly overflowed from the entire periphery of the recessed frame portion, and the coating is applied. Sometimes the droplets overflowed from the part where the first droplets did not overflow. Further, at that time, it was confirmed that the film thickness formed by overflow was thick.
Further, in the case where the treatment for improving lyophilicity was not performed, the case where the coating amount of the first droplet was increased to 8 droplets was also examined. In this case, it was possible to overflow the first droplet from the entire periphery of the concave frame portion, but the film thickness of the overflow portion was increased.

The results of measuring the recess cross-sectional shape in each case are shown in FIGS.
FIG. 3 is a diagram showing the measurement results of the cross-sectional shape of the recess after the defect correction using the method for partially forming the thin film of Example 2, and FIG. FIG. 5 is a diagram showing the measurement results of the recess cross-sectional shape after the defect was corrected by increasing the initial droplet amount as a comparative example.
In addition, in Example 2, although the lyophilic improvement process by ultraviolet-ray (UV) irradiation was demonstrated, the same effect was confirmed also in the method by solvent coating, surface roughening, and surfactant coating.
In addition, it was confirmed that the lyophilicity can be improved even by washing in the case where the lyophilicity is deteriorated due to contamination of the substrate surface.
In Example 2, since a weakly lyophilic substrate was used, it was indispensable to perform a treatment for improving lyophilicity. However, even in the substrate used in Example 1, surface contamination was observed. Needless to say, the lyophilic improvement treatment is effective when the lyophilicity varies.

  The ink having self-liquid repellency used in Examples 1 and 2 was a normal amount (less than 1%) of the silane-based surfactant added to the ink when the present inventors were conducting another study. It was discovered accidentally by adding about 10 times as much. Accordingly, the present inventors have studied an additive that can exhibit self-liquid repellency without impairing the original function of the ink. As a result, it has been found that the same liquid repellency can be obtained by adding about 5 times the normal addition amount of the fluorosurfactant. However, the addition of higher alcohols such as fluorine-based coating agents, silicone-based coating agents, and pentanol, which have been studied, cannot provide desired inks such as ink phase separation and the absence of self-liquid repellency. It was.

  Next, the influence of the difference in self-liquid repellency was investigated. First, the amount of the fluorine-based additive added was adjusted to prepare inks having self-repellency of approximately 10 °, 15 °, 20 °, and 25 ° in terms of contact angles. To check the self-repellency, one drop of the ink was again dropped on the substrate coated and dried by spin coating, and the contact angle was measured with a contact angle meter. The contact angle is considered to include an error of about ± 5 ° due to the influence of measurement accuracy and reading error, but it was confirmed by another method that the magnitude relationship was not changed. Correction was performed in the same manner as in Example 1 using these inks having different liquid repellency.

6A and 6B are diagrams showing the difference in the shape of the recessed portion after correction using inks having different self-liquid repellency. FIG. 6A shows ink having a contact angle of 10 °, and FIG. 6B shows contact. FIG. 6C shows an example in which an ink having an angle of 15 °, FIG. 6C shows an example in which an ink having a contact angle of 20 °, and FIG. 6D shows an example in which an ink having a contact angle of 25 ° is used.
As apparent from FIGS. 6A to 6D, the ink having a contact angle of 10 ° has insufficient liquid repellency of the initial droplets, and the overflow of the droplets during coating application cannot be suppressed. It can be seen that with an ink of 15 ° or more, the liquid repellency of the first droplet can suppress the overflow of the droplet during coating application.

It is a figure which shows the recessed part cross-sectional shape measurement result after performing defect correction using the partial formation method of the thin film of Example 1. FIG. It is a figure which shows the recessed part cross-sectional shape measurement result after correcting by the same process using the ink which does not have self-liquid repellency as a comparative example. It is a figure which shows the recessed part cross-sectional shape measurement result after performing defect correction using the partial formation method of the thin film of Example 2. FIG. It is a figure which shows a recessed part cross-sectional shape measurement result after performing a defect correction, without a lyophilic improvement process as a comparative example. It is a figure which shows the recessed part cross-sectional shape measurement result after increasing initial drop amount as a comparative example, and performing defect correction. FIGS. 6A and 6B are diagrams showing the difference in the cross-sectional shape of the recesses after correction using inks having different self-liquid repellency. FIG. 6A shows ink having a contact angle of 10 °, and FIG. FIG. 6C shows an example in which an ink having a contact angle of 20 ° is used, and FIG. 6D is an example in which an ink having a contact angle of 25 ° is used. 7A and 7B are diagrams schematically illustrating the structure of a pixel of a TFT liquid crystal panel, in which FIG. 7A is a plan view and FIG. 7B is a cross-sectional view taken along line XX in FIG. It is sectional drawing which shows the board | substrate which has a foreign material defect typically. It is a figure which shows the method of removing the foreign material defect shown in FIG. It is a figure which shows the correction process in the partial formation method of the thin film of this invention in order of a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inkjet head, 2 ... Infrared lamp, 3 ... Ultraviolet laser apparatus, 4 ... Glass substrate, 5 ... Insulating layer, 6 ... Foreign material, 7 ... Recessed part, 8 ... First drop application part, 9 ... Coat application part, 10 ... Gate wiring, 11 ... source wiring, 12 ... semiconductor layer, 13 ... transparent electrode, 14 ... liquid crystal.

Claims (5)

  In the method for partially forming a thin film, in which an ink containing a material for forming a thin film is applied using an ink jet, and the thin film is selectively formed in the concave portion, the thin film formed by applying the ink is contacted with the ink applied A step of applying by ink jet using the ink having an angle of 15 ° or more so as to overflow the concave portion, and a step of applying the ink corresponding to a required film thickness once or several times by ink jet A method for partially forming a thin film, comprising:   2. The method for partially forming a thin film according to claim 1, further comprising a step of drying at least the overflowed portion of the ink after applying the ink so as to overflow the recess.   The thin film portion according to claim 1, further comprising a treatment step of improving lyophilicity with respect to the ink applied to at least the periphery of the recess before applying the ink so as to overflow the recess. Forming method.   4. The method for partially forming a thin film according to claim 3, wherein the treatment step for improving the lyophilic property includes any one of ultraviolet irradiation, solvent coating, surface roughening, surfactant coating, and washing. .   5. The ink according to claim 1, wherein a contact angle of the thin film formed of the ink with respect to the ink is set to 15 ° or more by adding a fluorine-based or silane-based surfactant. Method for partially forming a thin film.

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