JP2005135687A - Ito multilayer film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a good-quality ITO multilayer film endowed with low resistance and low membrane stress and to provide its manufacturing method. <P>SOLUTION: The manufacturing method of the ITO multilayer film comprises a process of forming a first ITO film on an upper part of a plastic body at a base plate temperature of 20 to 120°C with the use of an ion plating method, and a process of forming a second ITO film on the first ITO film at a base plate temperature of 150 to 250°C with the use of the ion plating method. Since the first ITO film has the low membrane stress and the second ITO film has the low resistance, a good-quality ITO multilayer film endowed with the low resistance and the low membrane stress as a whole is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ITO multilayer film formed by laminating two or more ITO films and a method for producing the same.

  5A and 5B are cross-sectional views showing a color filter (color filter, CF) substrate of a liquid crystal color display.

  Reference is made to FIG. For example, on a glass substrate 71 having a thickness of 0.7 mm, a color filter (CF) resin layer 72 of three primary colors of red (R), blue (B), and green (G) is sequentially applied using a spin coater and patterned. Do. The thickness of the CF resin layer 72 is 2 to 3 μm. A black matrix 73 is formed between adjacent CF resin layers 72 to obtain a CF substrate 70.

  Reference is made to FIG. Since the CF resin layer 72 formed on the glass substrate 71 and the black matrix 73 have different thicknesses, irregularities are formed on the CF resin layer 72 side of the CF substrate 70. For this reason, an overcoat layer 74 of, for example, a maximum thickness of 1 μm formed of resin is laminated on the CF substrate 70 using a spin coater. The overcoat layer 74 has a smooth surface. An ITO (Indium Tin Oxide) film 75 (transparent electrode) having a thickness of 130 to 150 nm is formed on the smooth surface of the overcoat layer 74.

  The ITO film 75 is required to have transparency and low resistance characteristics. In the film forming process, it is required that the CF resin layer 72 and the overcoat layer 74 are not significantly damaged.

  As a method for forming the ITO film 75, a DC magnetron sputtering method, a DC + RF superimposed magnetron sputtering method, an ion plating method, or the like performed by an apparatus in which an RF (high frequency) apparatus is added to the DC magnetron sputtering apparatus can be used. Further, the required film quality of the ITO film 75 is, for example, in the case of ITO film formation on a CF substrate facing the TFT substrate, the surface resistivity is 20Ω / □ or less, and the transmittance is 95 for light having a wavelength of 550 nm, for example. % Or more. In addition, it is preferable to produce with the productivity which forms the film for one board | substrate within 30 second.

  The film stress of the ITO film having low resistance and high light transmittance (compressive stress acting in the in-plane direction of the ITO film) tends to increase. When the film stress of the ITO film 75 is large, problems such as buckling of the ITO film 75 and cracking of the CF resin layer 72 and overcoat layer 74 occur.

  In the conventional ITO film formation using an ion plating method by a plasma coating system, in order to realize a low film stress, a single-layer film formation is performed at room temperature under conditions that impair the resistance reduction. In this method, in addition to the resistance of the ITO film being increased, there is a problem that the resistance distribution is not uniform. Further, productivity is reduced.

  When the sputtering method is used, in order to realize the required film quality and preferable productivity of the ITO film 75, a necessary number of sputtering targets are prepared, and multilayer film formation is performed by changing the film formation conditions for each layer. Is common.

A substrate on which an ITO transparent conductive film having a low compressive stress and a low surface resistivity is formed has been proposed. (For example, see Patent Document 1.)
The transparent conductive film (ITO film) in this proposal is composed of a laminate of two layers. The first layer ITO film is formed by a method other than the arc discharge plasma method (sputtering method or EB vapor deposition), and the second layer ITO film is formed by the arc discharge plasma method. It is described that the first layer ITO film has a rough surface, which affects the growth of the second layer ITO film, so that the second layer ITO film becomes a low stress film.

  This two-layered transparent conductive film (ITO film) has a low surface resistivity characteristic of the second-layer ITO film and is a film having a small film stress as a whole.

  However, when the first layer ITO film is formed by sputtering, defects such as target particles adhering to the substrate, abnormal discharge, and unstable film quality are likely to occur. Furthermore, it is difficult to obtain a low resistance film. In addition, when the radio frequency (RF) ion plating method is used, the film formation rate is slowed down.

JP-A-11-335815

  An object of the present invention is to provide a high-quality ITO multilayer film having low resistance and low film stress, and a method for manufacturing the same.

  According to one aspect of the present invention, a step of forming a first ITO film on a plastic body using an ion plating method at a substrate temperature of 20 ° C. to 120 ° C., and on the first ITO film, There is provided an ITO multilayer film manufacturing method including a step of forming a second ITO film at a substrate temperature of 150 ° C. to 250 ° C. using an ion plating method.

  If this ITO multilayer film manufacturing method is used, the first ITO film has a low film stress and the second ITO film has a low resistance. Therefore, a good quality ITO having a low resistance and a low film stress as a whole. A multilayer film can be formed.

  According to another aspect of the present invention, an ITO multilayer film formed above a plastic body, wherein n is an integer greater than or equal to 2 and j is an integer smaller than n, the first above the plastic body. A first ITO film is formed from the layer to the jth layer, and a second ITO film is formed from the (j + 1) th layer to the nth layer on the first ITO film of the jth layer. There is provided an ITO multilayer film in which the total film stress of the first or second ITO film from the first layer to the nth layer does not exceed 0.4 GPa.

  This ITO multilayer film is a high-quality ITO multilayer film having a low film stress.

  According to the present invention, it is possible to provide a high-quality ITO multilayer film having low resistance and low film stress, and a method for manufacturing the same.

  In the ion plating method capable of high-speed film formation, single-layer film formation using one row of film formation sources is performed. However, for example, in order to perform ion plating film formation on a large substrate with high productivity, two-layer film formation may be performed using two rows of film formation sources.

  The inventors of the present application have considered using two or more rows of film forming sources to form two or more ITO films under different film forming conditions.

  For example, if the first ITO film is formed without heating at room temperature, the migration of the film-forming atoms becomes smaller and the film quality deteriorates, and an ITO film with high resistivity, low light transmittance, and low film stress can be obtained. Will be formed. In addition, if the second ITO film is formed by heating, the migration of film-forming atoms is increased, the film quality (crystallinity) is improved, and an ITO film having low resistivity, high light transmittance, and high film stress is obtained. Will be formed.

  The inventors of the present application considered whether a high-quality ITO multilayer film having low film stress and low resistance could be produced by combining two or more ITO films.

  FIG. 1 is a schematic view showing a film forming apparatus 10 capable of forming an ITO film using the method for producing an ITO multilayer film according to the embodiment.

  The film forming apparatus 10 includes a first film forming chamber 11 and a second film forming chamber 12 that can form an ITO film on a substrate by an ion plating method using a plasma coating system, for example. In the first film forming chamber 11 and the second film forming chamber 12, for example, a vacuum generator 11b including vacuum exhaust ports 11a and 12a connected to a vacuum pump, and working gas supply pipes 11c and 12c, respectively. 12b, gas inlets 11d and 12d, and hearths 11e and 12e.

  The insides of the first film formation chamber 11 and the second film formation chamber 12 can be evacuated from the vacuum exhaust ports 11a and 12a to be in an arbitrary reduced pressure (vacuum) state. In both film forming chambers, for example, working gas is introduced into the plasma generators 11b and 12b from the pipes 11c and 12c, and plasma is generated by the plasma generators 11b and 12b which are pressure gradient type plasma guns. A reactive gas can also be introduced into each film forming chamber from the gas inlets 11d and 12d. Plasma beams from the plasma generators 11b and 12b are incident on the hearths 11e and 12e in which the evaporated substances 11f and 12f are stored.

  A plasma beam is formed by the discharge generated between the plasma generators 11b and 12b and the hearths 11e and 12e, and the evaporated substances 11f and 12f stored in the hearths 11e and 12e are heated by the plasma beam to evaporate. The evaporated particles are ionized (activated) by a plasma beam, and film formation is performed on a film formation target object that has been transferred to each film formation chamber. For example, an ITO film is formed on the substrate.

  An object to be formed on which the ITO film is formed, for example, a substrate, is transported from left to right in the drawing (in the direction of the arrow; the direction from the first film formation chamber 11 toward the second film formation chamber 12). . Therefore, the first ITO film can be formed in the first film formation chamber 11, and the second ITO film can be formed thereon in the second film formation chamber 11. The film formation conditions for the ITO film in the first film formation chamber 11 and the film formation conditions for the ITO film in the second film formation chamber 12 can be different.

  In addition to the pressure gradient type plasma generator, a composite cathode type plasma generator can also be used as the plasma generators 11b and 12b.

  FIG. 2 is a cross-sectional view for explaining a method for manufacturing an ITO multilayer film according to an embodiment.

  For example, the CF substrate 70 shown in FIG. 5A is introduced into the film formation apparatus 10 and carried into the first film formation chamber 11. In the first film forming chamber 11, the first ITO film 75 a is formed on the CF resin layer 72 side on the CF substrate 70 on the condition that the film stress is reduced by ion plating using a plasma coating system. Film. For example, an amorphous film is formed on a low-temperature substrate. In order to realize a low film stress, the resistance value of the first ITO film 75a is increased.

  The CF substrate 70 on which the first layer ITO film 75 a is formed is carried into the second film formation chamber 12. In the second film forming chamber 12, a second ITO film 75b is formed on the first ITO film 75a by an ion plating method using a plasma coating system. The second ITO film 75b is formed under the condition that the resistance value becomes small. The second layer ITO film 75b has a high film stress in order to realize a low resistance value.

  It was found that an ITO multilayer film having both low resistance and low film stress can be realized by changing the film formation conditions and laminating the two ITO films 75a and 75b.

  FIG. 3 shows three samples (first to third samples) of an ITO multilayer film composed of two-layer ITO films prepared by using an ion plating method using a plasma coating system, and an ITO film having only one layer. It is a table | surface which shows the film thickness of each ITO film | membrane, the film | membrane stress of an ITO multilayer film, specific resistance, and the film-forming state on the CF resin layer 72 about a sample (4th and 5th sample).

  The first to third samples were produced on the CF substrate 70 in FIG. 5A by using the film forming apparatus shown in FIG. 1 and the ITO multilayer film manufacturing method described with reference to FIG. The thickness of the ITO multilayer film (the total thickness of the first ITO film 75a and the second ITO film 75b) was 150 nm. The fourth sample uses the second film forming chamber 12 instead of the first film forming chamber 11 of the film forming apparatus shown in FIG. 1, and uses the second method of manufacturing the ITO multilayer film described with reference to FIG. Among them, the ITO film 75b of the second layer was formed on the CF substrate 70 in FIG. The thickness was 150 nm.

  Further, the fifth sample uses the first film forming chamber 11 of the film forming apparatus shown in FIG. 1 and, among the ITO multilayer film manufacturing method described with reference to FIG. 2, the first ITO film 75a. Was formed on the CF substrate 70 in FIG. The film thickness was 150 nm. In this case, no film formation is performed in the second film formation chamber 12 of FIG.

  The first layer ITO film 75a was formed at an initial substrate temperature of room temperature (typically about 20 ° C. to 25 ° C.) without heating the substrate. The second layer ITO film 75b was formed by heating the substrate and setting the initial substrate temperature to 200 ° C. in order to form an ITO film having a low resistivity.

  The fourth sample is an ITO film with good crystallinity with a small specific resistance and a large film stress. On the other hand, the fifth sample is an ITO film having a large specific resistance but a small film stress and poor crystallinity.

  FIG. 4 is a table showing the results of tentatively obtaining those of the first to third samples from the respective film thicknesses from the film stress and specific resistance of the fourth and fifth samples. The calculation was performed on the assumption that the films of the fourth and fifth samples were uniformly formed on the films of the first to third samples.

  Compare FIG. 3 and FIG. Compared to the film stress and specific resistance of the first to third samples shown in FIG. 4, those shown in FIG. 3 are small in both film stress and specific resistance.

  This result suggests that the ITO multilayer film (first to third samples) formed in two stages is not a mere combination of the film of the fourth sample and the film of the fifth sample. .

  Please refer to FIG. The specific resistance of the first to third samples is larger than that of the fourth sample, but 1.2 times or less. On the other hand, the film stress of the first to third samples is less than a quarter of that of the fourth sample. Moreover, although the crack generate | occur | produced in the 4th sample, the 1st-3rd sample did not generate | occur | produce a wrinkle, a curvature, a crack, etc., and was formed favorable. It can be seen that the ITO multilayer film produced by changing the film forming conditions of each layer is a high-quality ITO multilayer film having low resistance and low film stress.

The first ITO film 75a is preferably formed under a temperature condition (20 to 120 ° C.) where the substrate temperature does not exceed 120 ° C. without heating the substrate. If possible, the substrate may be cooled. During the film formation, about ₂ to 5 sccm, for example, of H ₂ O is introduced to make the ITO film an amorphous film.

  The second ITO film 75b is preferably formed at a substrate temperature of 150 to 250 ° C. during film formation by heating the substrate.

  When the sum of the thickness of the first-layer ITO film 75a and the second-layer ITO film 75b is 150 nm, the first-layer ITO film 75a has a thickness of 50 to 100 nm. The thickness of the second ITO film 75b is also preferably 50 to 100 nm. Further, a combination of film thicknesses in which the total film stress after the multilayer film formation does not exceed 0.4 GPa is preferable. It is more preferable if the film thickness balance does not exceed 0.3 GPa.

  In the case of an ITO multilayer film composed of two ITO films, the resistivity and film stress can be controlled by changing the film thickness of the first ITO film 75a and the second ITO film 75b. . Also in the case of an ITO multilayer film composed of three or more ITO films, it is possible to produce an ITO multilayer film according to the application and required film quality by controlling the film thickness of each layer.

  For example, the first and second samples may be preferably used for a CF substrate facing the TFT substrate. The third sample could be suitably used for a CF substrate facing the STN substrate and a CF substrate facing the TFT substrate.

  If two layers of ITO films 75a and 75b are formed on a plastic body such as the CF resin layer 72 under the condition that the total film stress after the two layers are formed does not exceed 0.4 GPa, the overall resistance is low. A good quality ITO multilayer with low film stress will be made. If the condition does not exceed 0.3 GPa, a better ITO multilayer film will be produced.

  Furthermore, the ITO multilayer film can be formed of three or more ITO films. When forming an ITO multilayer film consisting of n layers, where n is 2 or more and j is an integer smaller than n, the first to j-th layers are formed under the film-forming conditions for obtaining a low-stress film. The total film stress of the ITO film from the first layer to the nth layer does not exceed 0.4 GPa under the film forming conditions for obtaining the low resistance film from the layer to the nth layer. If a film is formed on a plastic body such as the CF resin layer 72 under the condition of 4 GPa or less, a high-quality ITO multilayer film having a low resistance and a low film stress as a whole is produced.

  Furthermore, a more preferable ITO multilayer film can be produced if the film is formed under the condition that the sum of the ITO film stresses from the first layer to the nth layer does not exceed 0.3 GPa (below 0.3 GPa).

  Since the two ITO films 75a and 75b are both formed by the ion plating method, damage to the CF resin layer 72 can be reduced and an ITO multilayer film can be formed.

  Further, when the first layer ITO film 75 a is formed in the first film formation chamber 11, the second layer ITO film 75 b is formed on the other CF substrate 70 in the second film formation chamber 12. Since film formation is performed, productivity is not significantly reduced as compared with the case where only one ITO film is formed on the CF substrate 70.

  Although the first ITO film 75a is formed on the CF resin layer 72 and the black matrix 73 of the CF substrate 70, the overcoat layer 74 is formed on the CF resin layer 72 and the black matrix 73 of the CF substrate 70. Then, a first layer ITO film 75a may be formed thereon.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  In addition to forming high-quality ITO multilayer films on CF for color liquid crystal displays, etc., for example, high-quality ITO multilayers with low resistance, low film stress, and no wrinkles, warpage, cracks, etc. on plastic bodies such as films A film can be formed.

  Further, in the manufacture of organic EL elements, it is possible to form a high-quality ITO multilayer film on a large substrate of 5 generations or more.

It is the schematic which shows the film-forming apparatus which can form an ITO film | membrane using the manufacturing method of the ITO multilayer film by an Example. It is sectional drawing for demonstrating the manufacturing method of the ITO multilayer film by an Example. Regarding three samples of ITO multilayer film consisting of two layers of ITO film prepared by ion plating method using plasma coating system and one sample of ITO film, the thickness of each ITO film, ITO multilayer film It is a table | surface which shows the film stress, specific resistance, and the film-forming state on CF resin. It is a table | surface which shows the result of having calculated | required those of the 1st-3rd sample from each film thickness from the film stress and specific resistance of the 4th and 5th sample. (A) And (B) is sectional drawing which shows the color filter substrate of a liquid crystal color display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Film-forming apparatus 11 1st film-forming chamber 12 2nd film-forming chamber 11a, 12a Vacuum exhaust port 11b, 12b Plasma generator 11c, 12c Pipe 11d, 12d Gas inlet 11e, 12e Hearth 11f, 12f Evaporating substance 70 CF substrate 71 Glass substrate 72 CF resin layer 73 Black matrix 74 Overcoat layer 75, 75a, 75b ITO layer

Claims (8)

Forming a first ITO film above the plastic body using an ion plating method at a substrate temperature of 20 ° C. to 120 ° C .;
Forming a second ITO film on the first ITO film at a substrate temperature of 150 ° C. to 250 ° C. by using an ion plating method. The method for producing an ITO multilayer film according to claim 1, wherein H ₂ O is added in the step of forming the first ITO film. The method for producing an ITO multilayer film according to claim 1 or 2, wherein the plastic body is a color filter resin layer. n is an integer of 2 or more, j is an integer smaller than n, the first ITO film is formed from the first layer to the j-th layer above the plastic body, and the first ITO film of the j-th layer is formed. When forming the second ITO film from the (j + 1) th layer to the nth layer on the ITO film, the film of the first or second ITO film from the first layer to the nth layer The method for producing an ITO multilayer film according to any one of claims 1 to 3, wherein the first and second ITO films are formed under a condition that a total sum of stress does not exceed 0.4 GPa. n is an integer of 2 or more, j is an integer smaller than n, the first ITO film is formed from the first layer to the j-th layer above the plastic body, and the first ITO film of the j-th layer is formed. When forming the second ITO film from the (j + 1) th layer to the nth layer on the ITO film, the film of the first or second ITO film from the first layer to the nth layer The method for producing an ITO multilayer film according to any one of claims 1 to 3, wherein the first and second ITO films are formed under a condition that a total sum of stress does not exceed 0.3 GPa. An ITO multilayer film formed above a plastic body, where n is an integer greater than or equal to 2 and j is an integer smaller than n, the first ITO from the first layer to the jth layer above the plastic body A second ITO film is formed from the (j + 1) th layer to the nth layer on the first ITO film of the jth layer, and from the first layer to the nth layer An ITO multilayer film in which the total film stress of the first or second ITO film does not exceed 0.4 GPa. The ITO multilayer film according to claim 6, wherein a total sum of film stresses of the first or second ITO film from the first layer to the n-th layer does not exceed 0.3 GPa. The ITO multilayer film according to claim 6 or 7, wherein the plastic body is a color filter resin layer.

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