JP4704049B2 - Method for repairing recess of metal film and method for manufacturing color filter substrate - Google Patents

Description

  The present invention relates to a method for repairing a recess in a metal film and a method for manufacturing a color filter substrate, and more particularly, a method for repairing a recess in a metal film having a recess on an end surface and a black matrix composed of a metal film having an end surface over-etched. The present invention relates to a method for manufacturing a color filter substrate with repair.

  The liquid crystal display device is advantageous in that it is thinner and lighter than a CRT (Cathode Ray Tube), can be driven at a low voltage, and consumes less power. For this reason, liquid crystal display devices are used in various electronic devices such as televisions, notebook PCs (personal computers), desktop PCs, PDAs (mobile terminals), and mobile phones. In particular, an active matrix liquid crystal display device in which a TFT (Thin Film Transistor) is provided as a switching element for each pixel (sub-pixel) exhibits excellent display characteristics comparable to a CRT because of its high driving capability. In addition, it has come to be widely used in fields where CRT has been used, such as desktop PCs and televisions.

  In general, a liquid crystal display device includes two substrates and a liquid crystal sealed between the substrates. A pixel electrode, a TFT, and the like are formed on one substrate for each pixel, and a color filter facing the pixel electrode and a common electrode common to each pixel are formed on the other substrate. Hereinafter, the substrate on which the pixel electrode and the TFT are formed is called a TFT substrate, and the substrate on which the color filter is formed is called a color filter substrate. A structure in which liquid crystal is sealed between a TFT substrate and a color filter substrate is called a liquid crystal panel.

Usually, a light shielding film called a black matrix is formed on the color filter substrate in order to shield the area between adjacent pixels. This black matrix is formed of, for example, a metal film having a three-layer structure of Cr (chromium) / CrN (chromium nitride) / CrO (chromium oxide). The CrO film is used because of its low reflectance, and the Cr film is used because of its high light shielding property. Moreover, the CrN film is used because it has good adhesion to the CrO film and the Cr film.
Japanese Patent Laid-Open No. 61-150119

  FIG. 1 is a schematic cross-sectional view showing a black matrix 12 formed on a glass substrate 11. When the black matrix 12 is formed by patterning the above-described metal film having the three-layer structure, the end surface of the black matrix 12 may be over-etched to form the recess 13 as shown in FIG. This is because the etching rate of the CrN film 12b is higher than that of the CrO film 12a and the Cr film 12c.

  When the end surface of the black matrix 12 is over-etched as shown in FIG. 1, when the resin for the color filter is applied by the slit coater, the resin enters the concave portion 13 of the end surface of the black matrix 12 due to capillary action, and as a result, the color The filter thickness is partially reduced. As a result, for example, striped application unevenness or circular application unevenness as schematically shown in FIG. 2 may occur, which may cause deterioration in display quality of the liquid crystal display device. FIG. 2 shows an example of coating unevenness that occurs when a color filter resin is applied on a two-sided glass substrate by a slit coater.

  Japanese Patent Application Laid-Open No. 61-150119 discloses a method of filling a space (overhang portion) below a conductor layer, which is generated when an electrode of a thin film magnetic head is manufactured, with a resist. However, in the method disclosed in this publication, a resist film is formed in advance in a portion where a void is generated, and then a conductor layer is formed, and the recess 13 generated on the end face of the black matrix 12 is repaired. I can't.

  In view of the above, an object of the present invention is to provide a method for repairing a recess in a metal film that can repair a recess generated on the end face of the metal film and form a film with a uniform thickness on the substrate.

  Another object of the present invention is to provide a method for manufacturing a color filter substrate capable of preventing the occurrence of uneven coating due to the concave portions generated on the end face of the black matrix.

The above-described problem is that the first inclined surface having an angle with the upper surface of less than 90 degrees and the second inclined surface with an angle with the lower surface of less than 90 degrees, the first photoresist recess distance was cut into narrower becomes tapered inclined surface and the second inclined surface by applying a positive photoresist on a substrate a metal film provided is formed on the end surface A coating step for forming a film; an exposure step for exposing the entire surface of the photoresist film; and a development step for developing the photoresist film to leave the photoresist film in the recesses of the metal film. This is solved by the method for repairing a concave portion of the metal film.

Further, the above-described problem is a process of forming a laminated film by laminating a chromium oxide film, a chromium nitride film, and a chromium film on a substrate, and patterning the laminated film by a photolithography method to form a black matrix; A coating process for forming a photoresist film by coating a positive photoresist on the entire upper surface of the substrate; an exposure process for exposing the entire surface of the photoresist film; and developing the photoresist film to develop the black matrix. A color filter substrate manufacturing method comprising: a developing step of leaving the photoresist film in an over-etched portion of an end surface of the substrate; and a step of forming a color filter on the substrate on which the black matrix is formed. It is solved by.

  In the present invention, a resist film is applied to the entire upper surface of the substrate provided with a metal film (black matrix) having a concave portion on the end surface, subjected to a whole surface exposure process, and then a development process. The upper portion of the concave portion of the metal film functions as a mask, and the resist is not exposed by the exposure process, so that the resist remains in the concave portion even after the development process. Thereby, for example, when the color filter resin is applied on the substrate, the color filter has a uniform film thickness without being partially reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 3 is a cross-sectional view showing the structure of the liquid crystal panel.

  As shown in FIG. 3, the liquid crystal panel 100 includes a TFT substrate 110, a color filter substrate 130, and a liquid crystal layer 140 made of liquid crystal sealed therebetween. Polarizing plates 141a and 141b are disposed on both sides of the liquid crystal panel 100 in the thickness direction, respectively.

  A gate bus line 112 and an auxiliary capacitance bus line 113 are formed on a glass substrate 111 that is a base of the TFT substrate 110. The gate bus line 112 and the auxiliary capacitor bus line 113 are formed of a metal film formed by stacking, for example, Al (aluminum) -Ti (titanium).

On the gate bus line 112 and the auxiliary capacitor bus line 113, a first insulating film (gate insulating film) 114 made of, for example, SiO ₂ or SiN is formed. A semiconductor film (for example, an amorphous silicon film or a polysilicon film) 115 to be an active layer of the TFT 118 is formed in a predetermined region on the first insulating film 114. A channel protective film 116 made of SiN or the like is formed on the semiconductor film 115, and a source electrode 118 a and a drain electrode 118 b of the TFT 118 are formed on both sides of the channel protective film 116. A data bus line (not shown) connected to the drain electrode 118 b of the TFT 118 and an auxiliary capacitance electrode 119 are formed on the first insulating film 114. The data bus line extends in a direction orthogonal to the gate bus line 112.

  As shown in FIG. 3, the auxiliary capacitance electrode 119 is formed at a position facing the auxiliary capacitance bus line 113 with the first insulating film 114 interposed therebetween. The auxiliary capacitance bus line 113, the auxiliary capacitance electrode 119, and the first insulating film 114 therebetween constitute an auxiliary capacitance. The data bus line, the source electrode 118a, the drain electrode 118b, and the auxiliary capacitance electrode 119 are formed of, for example, a metal film formed by stacking Ti / Al / Ti.

  On these data bus lines, the source electrode 118a, the drain electrode 118b, and the auxiliary capacitance electrode 119, a second insulating film 120 made of, for example, SiN is formed. A pixel electrode 121 made of a transparent conductor such as ITO (Indium-Tin Oxide) is formed on the second insulating film 120. As shown in FIG. 3, the pixel electrode 121 is electrically connected to the source electrode 118a through a contact hole 120a provided in the second insulating film 120, and electrically connected to the auxiliary capacitance electrode 119 through the contact hole 120b. It is connected to the. An alignment film (not shown) made of polyimide or the like is formed on the pixel electrode 121.

  On the other hand, the black matrix 14, the color filter 60, and the common electrode 61 are formed on one surface side (lower side in FIG. 3) of the glass substrate 11 serving as the base of the color filter substrate 130.

  The black matrix 14 is disposed at a position facing the gate bus line 112, the data bus line, and the TFT 118 on the TFT substrate 110 side. In the present embodiment, the black matrix 14 is formed of a metal film formed by laminating Cr / CrN / CrO. There are three types of color filters 60, red, green, and blue, and one color filter is arranged for each pixel region. One pixel is constituted by three pixels of the adjacent red pixel, green pixel, and blue pixel, and various colors can be displayed.

  The common electrode 61 is formed of a transparent conductor such as ITO and is disposed on the color filter 60 (on the lower side in FIG. 3). An alignment film (not shown) such as polyimide is formed on the common electrode 61 (on the lower side in FIG. 3).

  Hereinafter, a method for manufacturing a color filter substrate according to an embodiment of the present invention will be described.

  4A to 4C and FIGS. 5A to 5D are cross-sectional views illustrating the method of manufacturing the color filter substrate of this embodiment in the order of steps. FIGS. 6A to 6C are enlarged views showing the cross section of the black matrix.

  First, as shown in FIG. 4A, a CrO film 12a, a CrN film 12b, and a Cr film 12c are stacked in this order from below on a glass substrate 11 by sputtering, and a metal film having a thickness of, for example, 150 nm is formed. Form. Then, this metal film is patterned by a photolithography method to form a black matrix 12.

  That is, after applying a photoresist on a metal film made of CrO / CrN / Cr to form a photoresist film, the photoresist film is exposed through a predetermined exposure mask. Next, a development process is performed to form an etching mask made of a photoresist. Then, the metal film is etched through the opening of the etching mask to form the black matrix 12. Thereafter, the etching mask is removed.

  Here, it is assumed that when the metal film is etched to form the black matrix 12, the end surface of the black matrix 12 is over-etched to form the recess 13 as shown in FIG. 6A.

  Next, as shown in FIG. 4B, a positive photoresist (for example, AFP500 manufactured by Clariant) is applied to the entire upper surface of the glass substrate 11 to form a photoresist film 41 having a thickness of, for example, 1.5 μm. Form. At this time, as shown in FIG. 6B, the photoresist is filled into the recess 13 on the end face of the black matrix 12 by capillary action. Thereafter, for example, pre-baking is performed at a temperature of 100 ° C. for 120 seconds.

  Next, the entire surface of the photoresist film 41 on the substrate 11 is exposed without using an exposure mask. The exposure amount at this time is preferably smaller than the recommended exposure amount when forming a resist pattern by a photoresist method. For example, the entire surface of the photoresist film 41 is exposed with half of the recommended exposure amount. In this exposure step, the resist filled in the recesses 13 of the black matrix 12 is not exposed.

  Next, development processing is performed on the photoresist film 41, and the exposed portion of the photoresist film 41 is removed as shown in FIG. The development time at this time is preferably shorter than the recommended development time for forming a resist pattern by a photoresist method. For example, the development process is completed in half the recommended development time. Thereby, as shown in FIG. 6C, the resist 42 remains only in the recess 13 of the black matrix 12.

  At this time, it is not necessary to leave all of the resist filled in the recess 13. As will be described later, when the color filter resin is applied, the amount of the color filter resin filled in the recesses 13 is small, and the color filter does not have to have large thickness unevenness. In this way, the repair of the recesses on the end face of the black matrix 12 is completed.

  Next, a photosensitive red color filter resin is applied to the entire upper surface of the glass substrate 11 using a slit coater, followed by exposure and development processing, as shown in FIG. Then, the red color filter 60R is formed.

  Next, a photosensitive green color filter resin is applied to the entire upper surface of the glass substrate 11 using a slit coater, and then subjected to exposure and development processing. As shown in FIG. Then, the green color filter 60G is formed.

  Next, a photosensitive blue color filter resin is applied to the entire upper surface of the glass substrate 11 using a slit coater, and then subjected to exposure and development processing. As shown in FIG. Then, the blue color filter 60B is formed.

  Next, as shown in FIG. 5D, ITO is formed on the entire upper surface of the glass substrate 11 by sputtering to form the common electrode 61. Thereafter, an alignment film made of polyimide is formed on the common electrode 61. In this way, a color filter substrate for a liquid crystal display device is completed.

  Hereinafter, the result of actually manufacturing the color filter substrate by the method for manufacturing the color filter substrate of the present embodiment and examining the application state of the color filter resin will be described.

  FIG. 7A is a scanning electron microscope (SEM) image showing a cross section of the over-etched black matrix. In this way, a positive photoresist (AF500 manufactured by Clariant) was applied to a substrate having a black matrix in which concave portions were formed on the end faces, thereby forming a photoresist film having a thickness of about 1.5 μm. Thereafter, prebaking was performed at a temperature of 100 ° C. for 120 seconds.

Next, the photoresist film was exposed. The exposure dose at this time is 35 mJ / cm ^2, which is half of the normal exposure dose (exposure dose when forming the black matrix). Then, a TMAH (tetramethylmethylammonium halidelite) developer having a concentration of 2.2% was sprayed for 20 seconds to perform development, and then rinsed with pure water. The spray time (development time) at this time is half of the normal spray time (spray time when forming the black matrix).

  In the experiments by the inventors of the present application, a sufficient amount of resist is formed in the recesses of the black matrix in both cases where only the exposure amount is halved and when only the development time is halved. It could not be left.

  FIG. 7B is an SEM image showing a cross section of the black matrix after the development processing. As shown in FIG. 7B, the resist is not completely filled in the recesses of the black matrix, but the depth of the recesses is shallower than that in FIG. 7A.

  In this way, after filling the black matrix with the resist, the color filter resin was applied to the entire upper surface of the glass substrate.

  FIG. 8A is an SEM image showing a cross section of the black matrix after applying the color filter resin. As shown in FIG. 8A, the color filter resin has entered the recess to a depth of 300 nm, but no coating unevenness was observed.

  On the other hand, for comparison, a color filter resin was applied directly on a black matrix having recesses as shown in FIG. FIG. 8B is an SEM image showing a cross section of the black matrix. As shown in FIG. 8B, the color filter resin has entered the recesses to a depth of 380 nm, and narrow pitch oblique stripe-like coating irregularities were observed.

  As described above, in the method for manufacturing a color filter substrate according to this embodiment, a positive photoresist is applied on a glass substrate on which a black matrix is formed, and the entire surface exposure process is performed without using a mask. Thereafter, development processing is performed so that the resist remains only in the recesses of the black matrix. Thereby, it is possible to prevent the occurrence of uneven coating in the step of applying the color filter resin, and it is possible to manufacture a liquid crystal display device with good display quality.

  In the present embodiment, the case where the concave portion is formed in the black matrix in the manufacturing process of the color filter substrate has been described. However, the present invention is not limited to this, and is applied to the repair when the concave portion is formed in the metal thin film. Is possible.

  In the above embodiment, the case where the step of etching the metal film to form the black matrix (etching step) and the step of filling the recesses of the black matrix by applying the photoresist has been described. Only when it is done, the step of repairing the recess with the photoresist may be performed. That is, after the metal film is etched to form a black matrix, a color filter resin is applied. Then, after inspecting the presence or absence of uneven coating, the color filter resin is peeled off when uneven coating occurs, and after that, the concave portion of the black matrix is filled with a photoresist as described above, and then the color filter resin is applied again. .

FIG. 1 is a schematic cross-sectional view showing a black matrix formed on a glass substrate. FIG. 2 is a diagram showing an example of coating unevenness that occurs when a color filter resin is coated on a glass substrate. FIG. 3 is a cross-sectional view showing the structure of the liquid crystal panel. FIG. 4 is a diagram (part 1) illustrating a manufacturing process of a color filter substrate. FIG. 5 is a diagram (part 2) illustrating the manufacturing process of the color filter substrate. FIG. 6 is a diagram showing a cross section of the black matrix. FIG. 7A is an SEM image showing an example of an over-etched black matrix. FIG. 7B is an SEM image showing an example of the repaired black matrix. FIG. 8A is an SEM image showing an example in which a color filter resist is coated on the black matrix in the state shown in FIG. FIG. 8B is an SEM image showing an example in which a color filter resist is applied to the black matrix in the state shown in FIG.

Explanation of symbols

11 ... Glass substrate,
12 ... Black matrix,
13 ... recess,
41 ... Positive photoresist,
60 ... color filter,
100 ... Liquid crystal panel,
130: Color filter substrate.

Claims (4)

The first inclined surface having an angle with the upper surface of less than 90 degrees and the second inclined surface with an angle with the lower surface of less than 90 degrees, and the first inclined surface and the first coating the concave portion the distance between the second inclined surface is cut in a tapered shape which narrows to form a photoresist film by applying a positive photoresist on a substrate a metal film provided is formed on the end surface Process,
An exposure step of exposing the entire surface of the photoresist film;
And a development step of developing the photoresist film to leave the photoresist film in the recess of the metal film.   The exposure amount in the exposure step is ½ of the exposure amount at the time of forming the photoresist pattern, and the development time in the development step is ½ of the development time at the time of forming the photoresist pattern. The method for repairing a recess in a metal film according to claim 1. Forming a laminated film by laminating a chromium oxide film, a chromium nitride film, and a chromium film on a substrate, and patterning the laminated film by a photolithography method to form a black matrix;
A coating step of coating a positive photoresist on the entire upper surface of the substrate to form a photoresist film;
An exposure step of exposing the entire surface of the photoresist film;
A development step of developing the photoresist film to leave the photoresist film in an over-etched portion of the end face of the black matrix;
And a step of forming a color filter on the substrate on which the black matrix is formed.   The exposure amount in the exposure step is ½ of the exposure amount at the time of forming the photoresist pattern, and the development time in the development step is ½ of the development time at the time of forming the photoresist pattern. The method for producing a color filter substrate according to claim 3.

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