JP2008108807A - Nonlinear element, method for fabricating nonlinear element, and electro-optic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonlinear element in which nitrogen can be distributed suitably over the entire thickness direction of a tantalum oxide film when a tantalum oxide film containing hydrogen and nitrogen is employed as an insulating layer, to provide its fabrication process, and to provide an electro-optic device. <P>SOLUTION: When a nonlinear element 10x is fabricated, a lower electrode 13x is composed of a tantalum film containing tungsten. With regard to the insulating layer 14x, the upper surface portion of the lower electrode 13x having a significant impact at least on the electrical characteristics is composed of a sputtered film 14y of a tantalum oxide film containing nitrogen, and an anodic oxidation film 14z is formed on the side face of the lower electrode 13x. Subsequently, hydrogen is introduced to the insulating layer 14x and since the surface layer of the sputtered film 14y is containing a large quantity of nitrogen similarly to the deep part thereof, sufficient hydrogen retentivity is ensured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-linear element including a lower electrode, an insulating layer, and an upper electrode, a method for manufacturing the non-linear element, and an electro-optical device including the non-linear element as a pixel switching element.

  As a non-linear element used as a pixel switching element in an active matrix type electro-optical device, for example, a TFD having a MIM (Metal-Insulator-Metal) structure including a lower electrode, an insulating layer, and an upper electrode is used. (Thin Film Diode). In such a non-linear element, generally, the lower electrode is made of a tantalum film, the insulating layer is made of a tantalum oxide film, and the upper electrode is made of a chromium film.

For such a nonlinear element, the surface of the lower electrode made of a nitrogen-containing tantalum film is anodized for the purpose of improving the contrast of the image displayed by the electro-optical device, so that the nitrogen-containing tantalum oxide is used as an insulating layer. It has been proposed to improve the nonlinearity of a nonlinear element by forming a film (see, for example, Patent Document 1).
JP-A-9-166792

  As a result of repeated experiments, the inventor of the present application obtains the knowledge that nonlinearity is improved when hydrogen is added to the insulating layer, and proposes to improve the nonlinearity based on this knowledge. However, when hydrogen is added to the insulating layer, an irreversible shift phenomenon of current-voltage characteristics occurs, and there is a problem that burn-in occurs in the displayed image. That is, when hydrogen is added to the insulating layer, hydrogen is desorbed from the insulating layer when a voltage is applied, and the nonlinearity is irreversibly lowered. As a result, in the pixels that have been energized to display the image, the linearity of the nonlinear element is reduced, and even when the image is switched, the trace of the image that has been displayed remains. The seizure phenomenon will occur.

  Therefore, the present inventor proposes to prevent hydrogen desorption by introducing nitrogen together with hydrogen into the insulating layer to enhance the hydrogen holding power of the insulating layer.

However, when an anodization is performed on the surface of the lower electrode made of a nitrogen-containing tantalum film (N-Ta) to form an insulating layer made of a nitrogen-containing tantalum oxide film (TaO _x N _y ), tantalum is ionized during the anodic oxidation. However, since nitrogen does not move, secondary ion mass spectrometry of the insulating layer shows the distribution of nitrogen atoms in the insulating layer in the film thickness direction as dots L31 in FIG. As shown by the dot L32 in the distribution in the film thickness direction, the nitrogen content is large in the deep part of the insulating layer made of the nitrogen-containing tantalum oxide film, whereas there are almost no nitrogen atoms in the surface layer part. For this reason, the surface layer portion of the insulating layer has a low hydrogen holding power, so that when the voltage is applied, if the hydrogen in the surface layer portion moves and desorbs toward the interface with the upper electrode, the element resistance decreases. If a part of hydrogen moves toward the interface with the lower electrode and is trapped by oxygen defects in a region where the nitrogen content is high, the charge carriers derived from oxygen defects are reduced, so that the device resistance is increased. As a result, there is a problem that image sticking or afterimage occurs. In addition, even during or immediately after introduction of hydrogen into the insulating layer by hydrogen plasma irradiation or hydrogen addition annealing, there is a problem that hydrogen is desorbed in the surface layer portion and a sufficient amount of hydrogen cannot be introduced.

  In view of the above problems, an object of the present invention is to use a tantalum oxide film containing hydrogen and nitrogen as an insulating layer, and to nonlinearly distribute nitrogen appropriately throughout the thickness direction of the tantalum oxide film. It is an object to provide an element, a method for manufacturing the nonlinear element, and an electro-optical device including the nonlinear element.

  In order to solve the above-described problems, the present invention provides a nonlinear element including a lower electrode, an insulating layer that covers a surface of the lower electrode, and an upper electrode that faces the lower electrode through the insulating layer. The electrode is constituted by a nitrogen-containing tantalum film, the insulating layer is constituted by a nitrogen-containing tantalum oxide film containing hydrogen, and at least a portion covering the upper surface of the lower electrode in the insulating layer is a nitrogen-containing tantalum oxide film It is characterized by comprising a sputtered film.

  In the present invention, since the nonlinear element contains hydrogen, the nonlinear element has high nonlinearity and can prevent the occurrence of an element drift phenomenon that causes an afterimage phenomenon. Moreover, the addition of nitrogen to the insulating layer also has an effect of improving nonlinearity. Furthermore, since nitrogen exhibits a function of preventing the desorption of hydrogen, it is possible to prevent occurrence of an irreversible shift phenomenon of non-linear characteristics that causes seizure. Here, in the nitrogen-containing tantalum oxide film formed by anodic oxidation, the nitrogen content in the surface layer portion is extremely low and the hydrogen retention capability is low. In the present invention, however, at least the upper surface of the lower electrode is covered in the insulating layer. The portion is constituted by a sputtered film of a nitrogen-containing tantalum oxide film, and the sputtered film also contains a large amount of nitrogen as well as the deep part of the insulating layer, and has a sufficient hydrogen holding power. Yes. Accordingly, when a voltage is applied, hydrogen in the surface layer portion does not move toward the interface with the upper electrode and desorb, so that the element resistance does not decrease. In addition, since hydrogen in the surface layer moves toward the interface with the lower electrode and is not trapped by oxygen defects in a region where the nitrogen content is high, the charge carriers derived from oxygen defects are not reduced, and the element resistance Does not increase. Therefore, according to the present invention, it is possible to prevent image sticking and afterimages from occurring. Furthermore, since the nitrogen content of the lower electrode and the insulating layer can be set to optimum conditions, a non-linear element with excellent non-linearity and a lower electrode with a low resistance should be formed on the same substrate. Can do.

  According to the present invention, a nitrogen-containing tantalum film is formed in a method for manufacturing a nonlinear element including a lower electrode, an insulating layer covering the surface side of the lower electrode, and an upper electrode facing the lower electrode via the insulating layer. A nitrogen-containing tantalum film forming step, a tantalum oxide film sputter forming step of sputter-forming a nitrogen-containing tantalum oxide film on the nitrogen-containing tantalum film, and patterning the nitrogen-containing tantalum film together with the nitrogen-containing tantalum oxide film A lower electrode patterning forming step for forming a lower electrode; and an anodic oxidation step for forming a nitrogen-containing tantalum oxide film on a side surface of the lower electrode by performing anodization with the lower electrode as an anode after forming the lower electrode patterning; And a hydrogen introduction step of introducing hydrogen into the nitrogen-containing tantalum oxide film.

  When such a manufacturing method is adopted, a portion covering the upper surface of the lower electrode is constituted by the sputtered film of the nitrogen-containing tantalum oxide film, and a portion covering the side surface of the lower electrode is constituted by the anodic oxide film of the lower electrode. A non-linear element can be manufactured.

  If comprised in this way, the nonlinear element which the part which covers the upper surface of a lower electrode consists of a sputter | spatter film | membrane of a nitrogen-containing tantalum oxide film can be manufactured with few processes. Here, the nitrogen-containing tantalum film is exposed at the side surface portion of the lower electrode at the stage where the lower electrode patterning formation process is completed. Covered. In addition, defects in the sputtered film of the nitrogen-containing tantalum oxide film can be repaired by an anodic oxidation process. Moreover, even if the insulating layer formed on the side surface is an anodic oxide film, the area of the side surface of the lower electrode is considerably smaller than the area of the upper surface, so that the electrical characteristics of the nonlinear element are not greatly affected. .

  In this case, in the lower electrode patterning forming step, it is preferable to pattern the nitrogen-containing tantalum film and the nitrogen-containing tantalum oxide film by dry etching. When the nitrogen-containing tantalum film and the nitrogen-containing tantalum oxide film are dry-etched in the lower electrode patterning process, an etching residue such as fluoride remains on the side surface of the lower electrode, and the etching residue has high insulation. For this reason, even if the insulating layer formed on the side surface portion is an anodic oxide film, the electrical characteristics of the nonlinear element are not greatly affected.

  In another embodiment of the present invention, in a method of manufacturing a nonlinear element including a lower electrode, an insulating layer covering the surface side of the lower electrode, and an upper electrode facing the lower electrode through the insulating layer, a nitrogen-containing tantalum A nitrogen-containing tantalum film forming step for forming a film; a lower electrode patterning forming step for patterning the nitrogen-containing tantalum film to form the lower electrode; and a nitrogen-containing tantalum oxide film on the surface side of the lower electrode. It has a tantalum oxide film sputter formation process and a hydrogen introduction process for introducing hydrogen into the nitrogen-containing tantalum oxide film.

  When such a manufacturing method is employed, the insulating layer can be manufactured as a non-linear element that is entirely composed of the sputtered film of the nitrogen-containing tantalum oxide film.

  If comprised in this way, since an anodizing process is not performed, a simplification of a process can be achieved.

  Here, after the tantalum oxide film sputtering formation step, it is preferable to perform an anodic oxidation step of anodizing with the lower electrode as an anode. With this configuration, the insulating layer is entirely composed of the sputtered film of the nitrogen-containing tantalum oxide film, and the sputtered film includes a non-linear element that has been subjected to anodization using the lower electrode as an anode. Can be manufactured.

  If comprised in this way, the defect of the sputtering film | membrane of a nitrogen-containing tantalum oxide film can be repaired by an anodic oxidation process.

  In the present invention, when the anodic oxidation step is performed, it is preferable to apply a voltage corresponding to the thickness of the sputtered film to the lower electrode. With this configuration, even when defects such as surface irregularities and pinholes are generated in the nitrogen-containing tantalum oxide film formed by sputtering, such defects can be eliminated in the anodic oxidation process, and anodic oxidation is performed. Since there is no film growth in the region where the sputtered film is formed during the process, it is possible to maintain a state where nitrogen is uniformly distributed in the entire thickness direction of the sputtered film.

  The method of manufacturing a nonlinear element according to the present invention can be used in a method of manufacturing an electro-optical device such as a liquid crystal device. In this case, the nonlinear element is formed as a pixel switching element in each of a plurality of pixel regions on the element substrate. To do. The electro-optical device according to the present invention is used in electronic devices such as a mobile phone and a mobile computer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing referred to in the following description, the scale may be different for each layer or each member in order to make the size recognizable on the drawing.

[Embodiment 1]
(Configuration of nonlinear element)
1A to 1E are cross-sectional views showing a nonlinear element to which the present invention is applied and a method for manufacturing the same. As shown in FIG. 1E, the nonlinear element 10x of this embodiment includes a lower electrode 13x made of a tantalum film, and an insulating layer 14x made of a tantalum oxide film covering the surface side (upper surface portion and side surface portion) of the lower electrode 13x. And a TFD (Thin Film Diode) element provided with an upper electrode 15x opposed to the lower electrode 13x through the insulating layer 14x. A base insulating layer (not shown) made of a tantalum oxide film or the like may be formed on the surface of the substrate 20x. In this case, the nonlinear element 10x is formed on the surface of the base insulating layer.

(Layer structure of nonlinear element)
2A to 2C are explanatory views showing the relationship between the material and electric characteristics of each layer constituting the nonlinear element. 2A is an explanatory view of the influence of the hydrogen and nitrogen contained in the insulating layer in the nonlinear element on the nonlinear element. FIG. 2B is a diagram of the tantalum film constituting the lower electrode of the nonlinear element. FIG. 2C is a graph showing the relationship between the nitrogen content and the specific resistance of the tantalum film, and the relationship between the nitrogen content of the tantalum oxide film constituting the insulating layer and the nonlinearity (β value) of the nonlinear element. 5 is a graph showing the relationship between the amount of hydrogen introduced and the element drift value when a nitrogen-containing tantalum oxide film is used as the insulating layer of the nonlinear element and when a tantalum oxide film not containing nitrogen is used.

  In the nonlinear element 10x, there is the following relationship described with reference to FIG. 2 between the material constituting each layer and the electrical characteristics. In this embodiment, the lower electrode 13x is constituted by a nitrogen-containing tantalum film, The insulating layer 14x is composed of a tantalum oxide film containing nitrogen and hydrogen.

  First, as shown in FIG. 2A, hydrogen improves the nonlinearity of the nonlinear element 10x and reduces the element drift phenomenon. Nitrogen improves the nonlinearity of the nonlinear element 10x while increasing the element drift phenomenon. Nitrogen also reduces the shift phenomenon by preventing the desorption of hydrogen.

  The element drift phenomenon is a phenomenon in which when the current-voltage characteristic is measured for the first time and then the current-voltage characteristic is measured for the second time, a difference occurs in the measurement result, and the insulation is high in the second measurement. It is. In such an element drift phenomenon, when the current-voltage characteristic is measured again after, for example, one hour has passed since the second measurement, the result equivalent to the first measurement result is obtained. -When the voltage characteristic is measured, a result showing high insulation is obtained as in the second measurement result. Such an element drift phenomenon is considered to occur due to ionic oxygen depletion in the insulating layer 14x being drawn to one of the lower electrode 13x / insulating layer 14x interface or the insulating layer 14x / upper electrode 15x interface, When the ionic oxygen depletion in the insulating layer 14x is gradually returned to the low resistance state where the oxygen depletion is uniformly distributed from the high resistance state where the ionic oxygen depletion is attracted to one interface, a reverse current is generated due to the movement of the oxygen depletion. As a result, the afterimage phenomenon occurs as a result of the response of the liquid crystal.

  The shift phenomenon is a phenomenon that occurs due to the desorption of hydrogen from the insulating layer 14x. When the hydrogen added to improve the nonlinearity is desorbed, the linearity of the nonlinear element 10x is irreversibly lowered. However, in the pixel in which the nonlinear element 10x is energized in order to display an image, even when the image is switched, the trace of the image displayed so far always remains, and a burn-in phenomenon occurs.

  As shown by a solid line L1 in FIG. 2B, when a tantalum oxide film containing nitrogen is used for the insulating layer 14x, the nonlinearity (β value) of the nonlinear element 10 is improved. Moreover, the non-linearity of the non-linear element 10 improves, so that the insulating layer 14x has much nitrogen content. On the other hand, in the lower electrode 13x, the relationship between the nitrogen content in the tantalum film and the specific resistance is such that, as shown by a dotted line L2 in FIG. Since the tantalum of the system (β phase) is formed, the specific resistance is high. However, when the nitrogen content in the tantalum film is changed from 0.25 at% to 0.7 at% or 0.8 at%, a cubic crystal is obtained. Since the mixed tantalum and tetragonal tantalum are mixed, the specific resistance decreases. Then, when the nitrogen content in the tantalum film is 0.7 to 0.8 at%, it becomes a cubic single-phase tantalum, so that the specific resistance shows a minimum value. When the nitrogen content in the tantalum film increases from 0.8 at% to 2 at%, it becomes pseudo cubic single-phase tantalum and the specific resistance increases. Further, when the nitrogen content in the tantalum film increases, a mixed phase of pseudo cubic tantalum and tantalum nitride is formed, and the specific resistance further increases. Therefore, when the lower electrode 13x is formed simultaneously with the wiring, the nitrogen content in the tantalum film is set in a range where the specific resistance of the wiring can be reduced.

(Nonlinear device manufacturing method)
FIG. 3 is a process diagram showing the method for manufacturing the nonlinear element according to the first embodiment of the present invention. In this embodiment, for the reasons described above, the lower electrode 13x is made of a nitrogen-containing tantalum film, and the insulating layer 14x is made of a nitrogen-containing tantalum oxide film. At this time, if the insulating layer 14x is formed by anodizing the surface of the lower electrode 13x made of a nitrogen-containing tantalum film, as described with reference to FIG. 14, the nitrogen content is large in the deep portion of the insulating layer 14x. On the other hand, the surface layer portion hardly contains nitrogen, and the surface layer of the insulating layer 14x has a low hydrogen retention. Therefore, in the present invention, the manufacturing method described below is employed to improve the insulating layer 14x so that sufficient nitrogen exists throughout the thickness direction.

  First, in this embodiment, in the nitrogen-containing tantalum film forming step ST10 shown in FIGS. 1A and 3, sputter formation is performed using tantalum as a target while introducing nitrogen gas and argon gas into the sputtering chamber. A tantalum-containing film 13 is formed on the entire surface of the substrate 20x.

  Next, in the tantalum oxide film sputtering formation step ST15 shown in FIG. 1B and FIG. 3, sputtering is performed using tantalum as a target while introducing nitrogen gas, oxygen gas and argon gas into the sputtering chamber. A sputtered film 14 of a nitrogen-containing tantalum oxide film is formed on the entire surface of the substrate 20x on the upper layer of the tantalum-containing film 13. In this embodiment, in the tantalum oxide film sputtering formation step ST15, the processing time and the like are adjusted to form the sputtering film 14 having a film thickness necessary for forming the insulating layer 14x.

  In this embodiment, since the sputtering method is used also in the nitrogen-containing tantalum film forming step ST10 and the target is common, the nitrogen-containing tantalum film forming step ST10 is performed while introducing nitrogen gas and argon gas into the sputtering chamber. The tantalum oxide film sputtering formation step ST15 can be performed by simply switching the gas introduced into the sputtering chamber to nitrogen gas, oxygen gas and argon gas.

Next, after forming a resist mask on the upper surface of the sputtered film 14 of the nitrogen-containing tantalum oxide film in the lower electrode patterning forming step ST20 shown in FIG. 1C and FIG. 3, sulfur hexafluoride (SF ₆ ) and oxygen The nitrogen-containing tantalum film 13 and the sputtered film 14 of the nitrogen-containing tantalum oxide film are patterned by dry etching using a mixed gas or the like. As a result, a lower electrode 13x having a sputtered film 14y of a nitrogen-containing tantalum oxide film on the upper surface is formed. At that time, a power supply line (not shown) used in the next anodizing step is also formed.

  Next, in the anodic oxidation step ST30 shown in FIGS. 1D and 3, anodic oxidation is performed in an aqueous solution (electrolytic solution) such as citric acid using the lower electrode 13x as an anode. At this time, since the sputtered film 14y having a sufficient thickness to function as the insulating layer 14x has already been formed on the upper surface of the lower electrode 13x, in the anodizing step ST30, the sputtered film 14y already formed is formed. A voltage corresponding to the thickness is applied to the lower electrode 13x. Accordingly, in the anodic oxidation step ST30, an anodic oxide film 14z made of a nitrogen-containing tantalum oxide film is formed on the side surface portion of the lower electrode 13x, but the growth of the nitrogen-containing tantalum oxide film does not occur on the upper surface portion of the lower electrode 13x. Only the defect of the insulating layer 14x made of the sputtered film of the nitrogen-containing tantalum oxide film is repaired. Thus, in this embodiment, the insulating layer 14x made of a nitrogen-containing tantalum oxide film is formed by the anodic oxide film 14z and the sputtered film 14y that has been subjected to the anodic oxidation treatment.

  Next, hydrogen is introduced into the insulating layer 14x in the hydrogen introduction step ST40 shown in FIG. Specifically, the processing chamber containing the substrate 20x is set to a temperature of about 320 ° C., and in this state, a gas containing water vapor, for example, the atmosphere, is introduced into the processing chamber to perform hydrogenation annealing. As hydrogenation annealing, pressurized water vapor may be supplied in a state where the substrate 20x is heated to a predetermined temperature. Moreover, as hydrogen introduction process ST40, it may replace with hydrogen addition annealing and may irradiate with hydrogen plasma.

  Next, although illustration is omitted, in the bridge portion removing step, the bridge portion (not shown) that has connected the lower electrode 13x and the feeder is removed. If the lower electrode 13x and the power supply line may be connected, it is not necessary to remove the bridge portion.

  Next, the upper electrode formation step ST50 shown in FIG. 1 (e) and FIG. 3 is performed. For this purpose, first, a chromium film is formed with a uniform thickness by sputtering or the like in the chromium film forming process, and then, in the chromium film patterning process, the chromium film is patterned using a photolithography technique, and the upper electrode 15x is formed. Form. As described above, the nonlinear element 10x is formed on the substrate 20x.

  Note that the hydrogen introduction step ST40 may be performed after the formation of the sputtered film 14 and before the formation of the upper electrode 15x after the bridge portion removing step. Further, the bridge portion removing step may be performed after the upper electrode forming step ST50.

(Main effects of this form)
As described above, the nonlinear element 10x of this embodiment has high nonlinearity because the insulating layer 14x contains hydrogen, and can prevent the occurrence of an element drift phenomenon that causes an afterimage phenomenon. Moreover, the addition of nitrogen to the insulating layer 14x also has an effect of improving the nonlinearity. Furthermore, since nitrogen exhibits a function of preventing the desorption of hydrogen, it is possible to prevent occurrence of an irreversible shift phenomenon of non-linear characteristics that causes seizure. Here, in the nitrogen-containing tantalum oxide film formed by anodic oxidation, the nitrogen content in the surface layer portion is extremely low and the hydrogen holding ability is low. In this embodiment, the upper surface of the lower electrode 13x is included in the insulating layer 14x. The covering portion is constituted by a sputtered film 14y of a nitrogen-containing tantalum oxide film, and the sputtered film 14y contains a large amount of nitrogen and has a sufficient hydrogen holding power, as in the deep part. . Therefore, when a voltage is applied, hydrogen in the surface layer portion of the insulating layer 14x does not move toward the interface with the upper electrode 15x and desorb, so that the element resistance does not decrease. Further, since hydrogen in the surface layer portion moves toward the interface with the lower electrode 13x and is not trapped by oxygen defects in a region where the nitrogen content is large, charge carriers derived from oxygen defects are not reduced, and the device Resistance does not increase. Therefore, according to the present invention, it is possible to prevent image sticking and afterimages from occurring.

  In addition, since the nitrogen contents of the lower electrode 13x and the insulating layer 14x can be set to optimum conditions, the nonlinear element 10x having excellent nonlinearity and the lower electrode 13x having the low resistance are formed on the same substrate 20x. Can be formed on top.

  Furthermore, according to the manufacturing method of the present embodiment, the nitrogen-containing tantalum film forming step ST10 and the tantalum oxide film sputter forming step ST15 can be performed continuously only by switching the gas introduced into the sputtering chamber. The non-linear element 10x in which the portion covering the upper surface of 13x is made of the sputtered film 14y of the nitrogen-containing tantalum oxide film can be manufactured with a small number of steps.

  Furthermore, in the manufacturing method of the present embodiment, the nitrogen-containing tantalum film is exposed on the side surface portion of the lower electrode 13x at the stage where the lower electrode patterning formation step ST20 is completed, but anodization is performed after the lower electrode patterning formation step ST20. In order to perform the process ST30, the side surface portion of the lower electrode 13x is covered with a sputtered film 14z of a nitrogen-containing tantalum oxide film. Further, the defect of the sputtered film 14y of the nitrogen-containing tantalum oxide film can be repaired by the anodic oxidation step ST30. At this time, since a voltage corresponding to the thickness of the sputtered film 14y is applied to the lower electrode 13x, there is no film growth in the region where the sputtered film 14y is formed. Therefore, it is possible to maintain a state in which nitrogen is uniformly distributed throughout the thickness direction in the sputtered film 14y.

  Even if the insulating layer 14x formed on the side surface portion is the anodic oxide film 14z, the area of the side surface portion of the lower electrode 13x is considerably narrower than the area of the upper surface portion, which greatly affects the electrical characteristics of the nonlinear element 10x. There is no effect. Moreover, in the present embodiment, in the lower electrode patterning formation step ST20, the nitrogen-containing tantalum film 13 and the sputtered film 14 of the nitrogen-containing tantalum oxide film are patterned by dry etching, so that etching residues such as sulfide and fluoride are left on the lower electrode 13x. The etching residue remaining on the side surface of the film is highly insulating. For this reason, even if the lower electrode 13x is covered with the anodic oxide film 14z in the insulating layer 14x, the electrical characteristics of the nonlinear element 10x are not greatly affected.

[Embodiment 2]
4 and 5 are process cross-sectional views and process diagrams illustrating a method for manufacturing a nonlinear element according to the second embodiment of the present invention. In the nonlinear element 10x of this embodiment, the basic configuration is the same as that of the first embodiment, such that the lower electrode 13x is made of a nitrogen-containing tantalum film and the insulating layer 14x is made of a nitrogen-containing tantalum oxide film. Therefore, common parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, first, in the nitrogen-containing tantalum film forming step ST10 shown in FIGS. 4A and 5, sputter formation is performed using tantalum as a target while introducing nitrogen gas and argon gas into the sputtering chamber. A tantalum-containing film 13 is formed on the entire surface of the substrate 20x.

  Next, after forming a resist mask on the upper surface of the nitrogen-containing tantalum film 13 in the lower electrode patterning formation step ST20 shown in FIG. 4B and FIG. 5, using a mixed gas of sulfur hexafluoride and oxygen or the like. The nitrogen-containing tantalum film 13 is patterned by dry etching to form the lower electrode 13x.

  Next, in the tantalum oxide film sputter formation step ST25 shown in FIG. 4C and FIG. 5, sputter formation is performed using tantalum as a target while introducing nitrogen gas, oxygen gas and argon gas into the sputter chamber. A sputter film 14 of a nitrogen-containing tantalum oxide film is formed on the entire surface of 20x. As a result, the surface side of the lower electrode 13x is covered with the sputtered film 14 of the nitrogen-containing tantalum oxide film. In the present embodiment, in the tantalum oxide film sputtering formation step ST25, the processing time and the like are adjusted to form the sputtering film 14 having a film thickness necessary for forming the insulating layer 14x.

  Next, in the tantalum oxide film patterning step ST26 shown in FIGS. 4D and 5, a resist mask is formed on the upper surface of the sputtered film 14 of the nitrogen-containing tantalum oxide film, and then mixed with sulfur hexafluoride and oxygen. The sputtered film 14 of the nitrogen-containing tantalum oxide film is patterned by dry etching using a gas or the like, and the insulating layer 14x is left in a region covering the lower electrode 13x and the like.

  Next, hydrogen is introduced into the insulating layer 14x in the hydrogen introduction step ST40 shown in FIG. Specifically, the processing chamber containing the substrate 20x is set to a temperature of about 320 ° C., and in this state, a gas containing water vapor, for example, the atmosphere, is introduced into the processing chamber to perform hydrogenation annealing. As hydrogenation annealing, pressurized water vapor may be supplied in a state where the substrate 20x is heated to a predetermined temperature. Moreover, as hydrogen introduction process ST40, it may replace with hydrogen addition annealing and may irradiate with hydrogen plasma.

  Next, an upper electrode formation step ST50 shown in FIGS. 4E and 5 is performed. For this purpose, first, a chromium film is formed with a uniform thickness by sputtering or the like in the chromium film forming process, and then, in the chromium film patterning process, the chromium film is patterned using a photolithography technique, and the upper electrode 15x is formed. Form. As described above, the nonlinear element 10x is formed on the substrate 20x.

  As described above, even in the nonlinear element 10x of the present embodiment, since the insulating layer 14x contains hydrogen as in the first embodiment, the nonlinearity is high and the occurrence of the element drift phenomenon that causes the afterimage phenomenon is caused. Can be prevented. Moreover, the addition of nitrogen to the insulating layer 14x also has an effect of improving the nonlinearity. Furthermore, since nitrogen exhibits a function of preventing the desorption of hydrogen, it is possible to prevent occurrence of an irreversible shift phenomenon of non-linear characteristics that causes seizure. Further, the insulating layer 14x is constituted by a sputtered film 14 of a nitrogen-containing tantalum oxide film, and the sputtered film 14 contains a large amount of nitrogen as in the deep part thereof, and has a sufficient hydrogen holding power. It has. Therefore, when a voltage is applied, hydrogen in the surface layer portion of the insulating layer 14x does not move toward the interface with the upper electrode 15x and desorb, so that the element resistance does not decrease. Further, since hydrogen in the surface layer portion moves toward the interface with the lower electrode 13x and is not trapped by oxygen defects in a region where the nitrogen content is large, charge carriers derived from oxygen defects are not reduced, and the device Resistance does not increase. Therefore, according to the present invention, it is possible to prevent image sticking and afterimages from occurring. In addition, since the nitrogen contents of the lower electrode 13x and the insulating layer 14x can be set to optimum conditions, the nonlinear element 10x having excellent nonlinearity and the lower electrode 13x having the low resistance are formed on the same substrate 20x. Can be formed on top.

[Embodiment 3]
6 and 7 are process cross-sectional views and process diagrams showing a method for manufacturing a nonlinear element according to the third embodiment of the present invention. The basic structure of the nonlinear element 10x of this embodiment is the same as that of the first and second embodiments, such as the lower electrode 13x being made of a nitrogen-containing tantalum film and the insulating layer 14x being made of a nitrogen-containing tantalum oxide film. Since they are similar, common parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, first, in the nitrogen-containing tantalum film forming step ST10 shown in FIGS. 6A and 7, sputter formation is performed using tantalum as a target while introducing nitrogen gas and argon gas into the sputtering chamber. A tantalum-containing film 13 is formed on the entire surface of the substrate 20x.

  Next, after forming a resist mask on the upper surface of the nitrogen-containing tantalum film 13 in the lower electrode patterning formation step ST20 shown in FIGS. 6B and 7, using a mixed gas of sulfur hexafluoride and oxygen or the like. The nitrogen-containing tantalum film 13 is patterned by dry etching to form the lower electrode 13x. At that time, a power supply line (not shown) used in the next anodizing step is also formed.

  Next, in the tantalum oxide film sputter formation step ST25 shown in FIG. 6C and FIG. 7, sputter formation is performed using tantalum as a target while introducing nitrogen gas, oxygen gas and argon gas into the sputtering chamber. A sputter film 14 of a nitrogen-containing tantalum oxide film is formed on the entire surface of 20x. As a result, the surface side of the lower electrode 13x is covered with the sputtered film 14 of the nitrogen-containing tantalum oxide film. In the present embodiment, in the tantalum oxide film sputtering formation step ST25, the processing time and the like are adjusted to form the sputtering film 14 having a film thickness necessary for forming the insulating layer 14x.

  Next, in the tantalum oxide film patterning step ST26 shown in FIGS. 6D and 7, a resist mask is formed on the upper surface of the sputtered film 14 of the nitrogen-containing tantalum oxide film, and then mixed with sulfur hexafluoride and oxygen. The sputtered film 14 of the nitrogen-containing tantalum oxide film is patterned by dry etching using a gas or the like, and the insulating layer 14x is left in a region covering the lower electrode 13x and the like.

  Next, in the anodic oxidation step ST30 shown in FIGS. 6E and 7, anodic oxidation is performed in an aqueous solution (electrolytic solution) such as citric acid using the lower electrode 13x as an anode. At this time, since the insulating layer 14x is already formed with a sufficient film thickness, in the anodizing step ST30, a voltage corresponding to the thickness of the insulating layer 14x already formed is applied to the lower electrode 13x. Therefore, in the anodic oxidation step ST30, defects in the insulating layer 14x made of the sputtered film of nitrogen-containing tantalum oxide film are repaired, but no film growth occurs.

  Next, hydrogen is introduced into the insulating layer 14x in the hydrogen introduction step ST40 shown in FIG. Specifically, the processing chamber containing the substrate 20x is set to a temperature of about 320 ° C., and in this state, a gas containing water vapor, for example, the atmosphere, is introduced into the processing chamber to perform hydrogenation annealing. As hydrogenation annealing, pressurized water vapor may be supplied in a state where the substrate 20x is heated to a predetermined temperature. Moreover, as hydrogen introduction process ST40, it may replace with hydrogen addition annealing and may irradiate with hydrogen plasma.

  Next, although illustration is omitted, in the bridge portion removing step, the bridge portion (not shown) that has connected the lower electrode 13x and the feeder is removed. If the lower electrode 13x and the power supply line may be connected, it is not necessary to remove the bridge portion.

  Next, the upper electrode formation step ST50 shown in FIG. 6 (f) and FIG. 7 is performed. For this purpose, first, a chromium film is formed with a uniform thickness by sputtering or the like in the chromium film forming process, and then, in the chromium film patterning process, the chromium film is patterned using a photolithography technique, and the upper electrode 15x is formed. Form. As described above, the nonlinear element 10x is formed on the substrate 20x.

  The hydrogen introduction step ST40 may be performed after the formation of the sputtered film 14 of the nitrogen-containing tantalum oxide film and before the formation of the upper electrode 15x after the bridge portion removing step. Further, the bridge portion removing step may be performed after the upper electrode forming step ST50.

  As described above, even in the nonlinear element 10x of this embodiment, since the insulating layer 14x contains hydrogen as in the first and second embodiments, the nonlinearity is high and the element drift phenomenon that causes the afterimage phenomenon is caused. Occurrence can be prevented. Moreover, the addition of nitrogen to the insulating layer 14x also has an effect of improving the nonlinearity. Furthermore, since nitrogen exhibits a function of preventing the desorption of hydrogen, it is possible to prevent occurrence of an irreversible shift phenomenon of non-linear characteristics that causes seizure. Further, the insulating layer 14x is made of a sputtered film of a nitrogen-containing tantalum oxide film. The sputtered film has a surface layer portion containing a large amount of nitrogen as well as a deep portion thereof, and has sufficient hydrogen holding power. ing. In addition, since the nitrogen contents of the lower electrode 13x and the insulating layer 14x can be set to optimum conditions, the nonlinear element 10x having excellent nonlinearity and the lower electrode 13x having the low resistance are formed on the same substrate 20x. Can be formed on top.

  Furthermore, in this embodiment, since the defect of the insulating layer 14x made of the sputtered film of the nitrogen-containing tantalum oxide film is repaired by the anodic oxidation step ST30, the reliability of the nonlinear element 10 can be improved. At this time, since a voltage corresponding to the thickness of the insulating layer 14x (sputtered film 14) is applied to the lower electrode 13x, there is no film growth in the region where the insulating layer 14x is formed. Accordingly, it is possible to maintain a state where nitrogen is uniformly distributed in the entire thickness direction in the sputtered film 14.

[Modifications of Embodiments 2 and 3]
In the third embodiment, the tantalum oxide film patterning process ST26 is performed after the tantalum oxide film sputtering process ST25, and the insulating layer 14x is left only in the region covering the lower electrode 13x and the like. FIG. After performing the nitrogen-containing tantalum film forming step shown in FIG. 8B, the lower electrode patterning forming step shown in FIG. 8B, and the tantalum oxide film sputtering forming step shown in FIG. The sputtered film 14 of the nitrogen-containing tantalum oxide film sputter-formed on the entire surface of the substrate 20x in the oxide film sputter forming process is left as it is as the insulating layer 14x, and the anodizing process and hydrogen introducing process (not shown) shown in FIG. And the upper electrode forming step shown in FIG. 8E may be performed to form the nonlinear element 10x. Since other configurations are the same as those of the third embodiment, description thereof is omitted. The configuration of this embodiment may be applied to the second embodiment.

[Example of application to electro-optical devices]
(overall structure)
FIG. 9 is a block diagram showing an electrical configuration of an active matrix type electro-optical device (liquid crystal device) to which the present invention is applied. FIG. 10 is a cross-sectional view schematically showing a configuration of an electro-optical device to which the present invention is applied.

  As shown in FIG. 9, in the electro-optical device 100, a plurality of scanning lines 51 are formed extending in the row (X) direction, and a plurality of data lines 52 are extended in the column (Y) direction. Is formed. Further, pixels 53 are formed at positions corresponding to the intersections of the scanning lines 51 and the data lines 52, and these pixels 53 are arranged in a matrix. In each pixel 53, the liquid crystal layer 54 and the nonlinear element 10 made of TFD are connected in series. In the example shown in FIG. 9, the liquid crystal layer 54 is on the scanning line 51 side, and the nonlinear element 10 is on the data line 52. Connected to each side. The liquid crystal layer 54 may be connected to the data line 52 side, and the nonlinear element 10 may be connected to the scanning line 51 side. Here, each scanning line 51 is driven by a scanning line driving circuit 57, while each data line 52 is driven by a data line driving circuit 58.

  Specifically, such an electro-optical device 100 is configured as shown in FIG. 10, for example. In FIG. 10, one of the pair of substrates arranged opposite to each other is the element substrate 20 on which the nonlinear element 10 and the pixel electrode are formed, and the other substrate is the opposite substrate 30. Among these substrates, on the inner surface of the element substrate 20, a plurality of data lines 52, a plurality of nonlinear elements 10 connected to the data lines 52, and a one-to-one connection with the nonlinear elements 10 are connected. The pixel electrode 23 to be formed is formed. The data lines 52 are formed so as to extend in a direction perpendicular to the paper surface in FIG. 10, while the nonlinear elements 10 and the pixel electrodes 23 are arranged in a dot matrix. An alignment film 24 subjected to uniaxial alignment processing, for example, rubbing processing, is formed on the surface of the pixel electrode 23 and the like.

  A color filter 38 is formed on the inner surface of the counter substrate 30 and constitutes a colored layer of three colors “R”, “G”, and “B”. Note that a black matrix 39 is formed in the gap between the colored layers of these three colors to block incident light from the gap between the colored layers. A planarizing film 37 is formed on the surfaces of the color filter 38 and the black matrix 39, and a counter electrode 31 functioning as a scanning line 51 is formed on the surface in a direction perpendicular to the data lines 52. The planarizing film 37 is provided for the purpose of improving the smoothness of the color filter 38 and the black matrix 39 and preventing the counter electrode 31 from being disconnected. Further, an alignment film 34 subjected to a rubbing process is formed on the surface of the counter electrode 31, and the alignment films 24 and 34 are generally formed of polyimide or the like.

  The element substrate 20 and the counter substrate 30 are bonded to each other with a predetermined gap by a sealing material 104 including a spacer (not shown), and the liquid crystal 105 is sealed in the gap. A polarizing plate 217 having an optical axis corresponding to the rubbing direction to the alignment film 24 is attached to the outer surface of the element substrate 20, and the outer surface of the counter substrate 30 corresponds to the rubbing direction to the alignment film 34. A polarizing plate 317 having an optical axis is attached. Note that the electro-optical device 100 according to this embodiment employs a COG (Chip On Glass) technique, and the liquid crystal driving IC chip 260 is mounted directly on the surface of the element substrate 20.

(Configuration of pixel 53)
11 is a plan view showing a layout for several pixels including the TFD in the electro-optical device to which the present invention is applied, and FIG. 12 is an explanatory diagram of the TFD formed in each pixel shown in FIG. .

  As shown in FIGS. 11 and 12, the nonlinear element 10 of the present embodiment has a Back-to-Back structure including a first TFD 10a and a second TFD 10b. That is, the non-linear element 10 is formed on the lower layer 13b formed on the surface of the element substrate 20 and the insulating layer 14b formed on the surface of the lower electrode 13b. The upper electrode 15a and 15b which were spaced apart are provided, and the upper surface and side surface of the lower electrode 13b and the upper electrode 15a and 15b are opposed to each other through the insulating layer 14b. The upper electrode 15 a is formed integrally with the metal layer 15 c that becomes the data line 52 as it is, while the upper electrode 15 b is connected to the pixel electrode 23. The data line 52 includes a tantalum wiring 13a formed simultaneously with the lower electrode 13b. An insulating layer 14a formed simultaneously with the insulating layer 14b is formed on the surface of the tantalum wiring 13a. The underlayer 201 is made of, for example, a tantalum oxide film having a thickness of about 50 to 200 nm, and may be omitted depending on the structure of the lower electrode 13b.

  In the nonlinear element 10 of this embodiment, the lower electrode 13b and the tantalum wiring 13a are formed of a tantalum film having a thickness of about 50 to 150 nm, for example, and the tantalum film contains nitrogen. As will be described later, the insulating layers 14a and 14b are at least a portion formed on the upper surface of the metal layer 13a and the lower electrode 13b is a tantalum oxide film having a thickness of about 20 to 40 nm formed by sputtering. The tantalum oxide film contains nitrogen and hydrogen. The upper electrodes 15a and 15b are formed to a thickness of about 100 to 500 nm by a metal film such as chromium (Cr).

  When viewed from the data line 52 side, the first TFD 10a is, in order, an upper electrode 15a / insulating layer 14b / lower electrode 13b to form a sandwich structure of metal (conductor) / insulator / metal (conductor). Therefore, it has diode switching characteristics. On the other hand, when viewed from the data line 52 side, the second TFD 10b becomes the lower electrode 13b / insulating layer 14b / upper electrode 15b in order, and has a diode switching characteristic opposite to that of the first TFD 10a. Become. Therefore, since the nonlinear element 10 has a configuration in which two diodes are connected in series in opposite directions, the current-voltage nonlinear characteristics are symmetric in both positive and negative directions compared to the case where one diode is used. Will be. If it is not necessary to strictly symmetrize the nonlinear characteristics as described above, only one nonlinear element may be used.

  The pixel electrode 23 is formed of a conductive transparent film such as ITO (Indium Tin Oxide) when used as a transmissive type, while having a reflectivity such as aluminum or silver when used as a reflective type. It may be formed from a large reflective metal film. Note that the pixel electrode 23 may be formed of a transparent metal such as ITO even if it is a reflective type. In this case, after the reflective metal as the reflective layer is formed, the transparent pixel electrode 23 is formed through the insulating layer. On the other hand, when it is used as a transflective type, the reflective layer is formed thin to form a transflective film, or a slit is provided. As the element substrate 20 itself, for example, an insulating substrate such as quartz or glass is used. When used as a transmission type, the element substrate 20 is also required to be transparent, but when used as a reflection type, it is not necessary to be transparent. The reason why the base layer 201 is provided on the surface of the element substrate 20 is to prevent the lower electrode 13b and the like from being peeled from the base by heat treatment, and to prevent impurities from diffusing into the lower electrode 13b. Therefore, if this does not cause a problem, the base layer 201 can be omitted.

(Method of manufacturing electro-optical device 100)
FIG. 13 is a process diagram illustrating a manufacturing process of a nonlinear element in the manufacturing method of the electro-optical device 100 of the present embodiment, in which a cross-sectional view is shown on the left side and a plan view is shown on the right side.

  In this embodiment, when the electro-optical device 100 is manufactured, the element substrate forming process including the nonlinear element forming process to the sealing material printing process and the counter substrate forming process including the color filter forming process to the rubbing process are performed separately. Is called. In addition, these steps are performed in a state of a large original substrate that can take a large number of the element substrate 20 and the counter substrate 30, but in the following description, the single substrate size and the large original substrate are not distinguished, and the element substrate 20 Also referred to as counter substrate 30.

  In this embodiment, by performing a nonlinear element formation process on the large element substrate 20, the data lines 52 and the nonlinear elements 10 for a plurality of electro-optical devices are formed. In this nonlinear element formation step, the manufacturing method described in the first, second, and third embodiments and the modified example of the third embodiment is applied. In the following description, an example in which the method according to the first embodiment described with reference to FIGS. 1 and 3 is applied will be described.

  First, in the base film forming step shown in FIG. 13A, an insulating layer such as tantalum oxide having a thickness of about 50 to 200 nm is formed on the entire surface of the element substrate 20 to a uniform thickness. The formation 201 is formed.

  Next, in the nitrogen-containing tantalum film forming step shown in FIG. 13B, sputter formation is performed using tantalum as a target while introducing nitrogen gas and argon gas into the sputter chamber, and nitrogen having a thickness of 50 to 150 nm is formed. A tantalum-containing film 13 is formed on the entire surface of the element substrate 20.

  Next, in the tantalum oxide film sputter formation step shown in FIG. 13C, sputter formation is performed using tantalum as a target while introducing nitrogen gas, oxygen gas and argon gas into the sputtering chamber, and the nitrogen-containing tantalum film 13 is formed. A sputtering film 14 of a nitrogen-containing tantalum oxide film is formed on the entire surface of the element substrate 20 as an upper layer. In the present embodiment, in the tantalum oxide film sputter formation step, the sputter film 14 having a film thickness necessary for forming the insulating layer 14b, for example, a sputter film 14 having a thickness of 20 to 40 nm, is formed by adjusting the processing time and the like. To do. In this embodiment, the sputtering method is used for both the nitrogen-containing tantalum film forming step and the tantalum oxide film sputter forming step, and since the target is common, nitrogen is contained while introducing nitrogen gas and argon gas into the sputtering chamber. After performing the tantalum film forming step, the tantalum oxide film sputter forming step can be performed simply by switching the gas introduced into the sputtering chamber to nitrogen gas, oxygen gas and argon gas.

  Next, in the lower electrode patterning forming step shown in FIG. 13D, after forming a resist mask on the upper surface of the sputtered film 14 of the nitrogen-containing tantalum oxide film, a mixed gas of sulfur hexafluoride and oxygen is used. By this dry etching, the nitrogen-containing tantalum film 13 and the sputtered film 14 of the nitrogen-containing tantalum oxide film are patterned. As a result, a lower electrode 13b having a sputtered film 14y of a nitrogen-containing tantalum oxide film on the upper surface is formed. At this time, the tantalum wiring 13a of the data line 52 is simultaneously formed. In this state, the tantalum wiring 13a and the lower electrode 13b are connected by the bridge portion 13c. A sputtered film 14y is also formed on the upper layer of the tantalum wiring 13a.

  Next, in the anodic oxidation step shown in FIG. 13 (e), anodic oxidation is performed in an aqueous solution (electrolytic solution) such as citric acid using the lower electrode 13 as an anode. At this time, since the sputtered film 14y having a sufficient thickness to function as the insulating layer 14b has already been formed on the upper surface of the lower electrode 13b, etc., in the anodizing step, the sputtered film 14y already formed is formed. A voltage corresponding to the thickness is applied to the lower electrode 13. Therefore, in the anodic oxidation process, an anodic oxide film 14z made of a nitrogen-containing tantalum oxide film is formed on the side surface portion of the lower electrode 13b. However, the growth of the nitrogen-containing tantalum oxide film does not occur on the upper surface portion of the lower electrode 13b. Only the defect of the sputtered film 14y of the tantalum oxide film is repaired. Thus, in this embodiment, the insulating layer 14b made of a nitrogen-containing tantalum oxide film is formed by the anodic oxide film 14z and the sputtered film 14y that has been subjected to the anodizing treatment. Similarly, on the surface side of the tantalum wiring 13a, an insulating layer 14a is formed by the anodized film 14z and the sputtered film 14y subjected to the anodizing treatment.

  Next, hydrogen is introduced into the insulating layer 14b in the hydrogen introduction step. Specifically, the temperature of the processing chamber containing the element substrate 20 is set to about 320 ° C., and in this state, a gas containing water vapor, for example, the atmosphere, is introduced into the processing chamber to perform hydrogenation annealing. In addition, as hydrogenation annealing, pressurized water vapor may be supplied in a state where the element substrate 20 is heated to a predetermined temperature. Moreover, as a hydrogen introduction | transduction process, it may replace with hydrogen addition annealing and may irradiate with hydrogen plasma.

  Next, in the bridge portion removing step shown in FIG. 13 (f), the bridge portion 13c connecting the lower electrode 13b and the tantalum wire 13a is removed. As a result, the lower electrode 13b and the insulating layer 14b are separated from the data line 52 in an island shape. In this step, in addition to the bridge portion 13c, unnecessary portions that remain on the element substrate 20 when the large element substrate 20 is cut are also removed from the power supply pattern. Further, the base layer 201 in the region corresponding to the pixel electrode 23 is removed as necessary.

  Next, the upper electrode forming step shown in FIG. For this purpose, first, in the chromium film forming step, Cr having a thickness of about 100 to 500 nm is formed with a uniform thickness by sputtering or the like, and then in the chromium film patterning step, using photolithography technology, The film is patterned to form the metal layer 15c as the uppermost layer of the data line 52, the upper electrode 15a of the first TFD 10a, and the upper electrode 15b of the second TFD 10b. As described above, the necessary number of nonlinear elements 10 (TFDs 10 a and 10 b) are formed on the surface of the element substrate 20. Note that the bridge portion removing step shown in FIG. 13F may be performed after the upper electrode forming step.

  Although illustration of subsequent manufacturing steps is omitted, after forming ITO with a uniform thickness by sputtering or the like to form the pixel electrode 23, the ITO film is patterned, and a part of the pixel electrode 23 is formed. It is formed so as to overlap the upper electrode 15b. Through the series of steps, the nonlinear element 10 and the pixel electrode 23 shown in FIGS. 11 and 12 are formed. After that, in the alignment film process P3, after forming the alignment film 24 by forming polyimide, polyvinyl alcohol, etc. in a uniform thickness on the surface of the element substrate 20 (see FIG. 10), in the rubbing treatment process, A rubbing process or other alignment process is performed on the alignment film 24. Next, in the sealing material printing step, the sealing material 104 (see FIG. 10) is annularly applied by a dispenser, screen printing, or the like. Note that a liquid crystal injection port is formed in part of the sealing material 104.

  Separately from the above element substrate forming process, an opposing substrate forming process (color filter forming process to rubbing process) is performed. First, as shown in FIG. 10, after preparing a large counter substrate 30 formed of a light-transmitting material such as a glass substrate, black color is formed on the surface of the large counter substrate 30 in the color filter forming step. A matrix 39 and a color filter 38 are formed. Here, when color display is not necessary, the color filter 38 need not be formed. Next, in the flattening layer forming step, the flattening film 37 is formed to a uniform thickness on the color filter 38 to flatten the surface. Next, in the counter electrode forming step, the stripe-shaped counter electrode 31, that is, the scanning line 51 is formed using an ITO film or the like. Next, after an alignment film 34 having a uniform thickness is formed on the scanning line 51 or the like with polyimide or the like in the alignment film formation process, an alignment process such as a rubbing process is performed on the alignment film 34 in the rubbing process process. Apply.

  Thereafter, the large element substrate 20 and the large counter substrate 30 are aligned, and the sealing material 104 is sandwiched therebetween (bonding step), and the sealing material 104 is cured by ultraviolet curing or other methods ( Sealing material curing step). As a result, an empty panel structure including a plurality of liquid crystal devices is formed. Thereafter, the empty panel structure is cut into strip-shaped panel structures (primary cutting step 3). At the cut portion of the strip-shaped panel structure, the liquid crystal injection port consisting of the cut off portion of the sealing material 104 is opened to the outside. Therefore, after the liquid crystal is injected from the exposed liquid crystal injection port to the inside of the panel structure under reduced pressure. (Liquid crystal injection step) A sealing material such as resin is applied to each liquid crystal injection port to seal each liquid crystal injection port (injection port sealing step). In addition, since a liquid crystal adheres to a panel structure body by this process, the panel structure body which finished injecting the liquid crystal is cleaned (cleaning process). Thereafter, the panel structure is further cut to cut out a plurality of electro-optical devices 100 (secondary cutting step). Thereafter, the liquid crystal driving IC chip 260 and the like are mounted on the electro-optical device 100 to complete the electro-optical device 100 (mounting process).

[Other application examples to electro-optical devices]
In the above embodiment, since the TN mode or VAN mode liquid crystal device (electro-optical device) has been described as an example, the counter electrode is formed on the counter substrate. However, the pixel electrode and the counter electrode (common electrode) are formed on the element substrate. The present invention may be applied to a liquid crystal device (electro-optical device) in IPS (In-Plane Switching) mode or FFS (Fringe Field Switching) mode in which both of the above are formed.

[Example of mounting on electronic devices]
The electro-optical device to which the present invention is applied includes a personal computer (PC), an engineering work station (EWS), a pager, a word processor, a television, a viewfinder type or a monitor in addition to a mobile phone or a mobile personal computer. In addition to being applicable to electronic devices such as direct-view video tape recorders, electronic notebooks, electronic desk calculators, car navigation devices, POS terminals, touch panels, etc., they are used to construct electronic devices with large screens exceeding 30 inches. You can also.

(A)-(e) is sectional drawing which shows the nonlinear element which concerns on Embodiment 1 of this invention, and its manufacturing method. It is explanatory drawing which shows the relationship between the material of each layer which comprises a nonlinear element, and an electrical property. It is process drawing which shows the manufacturing method of the nonlinear element which concerns on Embodiment 1 of this invention. (A)-(e) is process sectional drawing which shows the manufacturing method of the nonlinear element which concerns on Embodiment 2 of this invention. It is process drawing which shows the manufacturing method of the nonlinear element which concerns on Embodiment 2 of this invention. (A)-(f) is process sectional drawing which shows the manufacturing method of the nonlinear element which concerns on Embodiment 3 of this invention. It is process drawing which shows the manufacturing method of the nonlinear element which concerns on Embodiment 3 of this invention. (A)-(e) is process sectional drawing which shows the manufacturing method of the nonlinear element which concerns on the modification of Embodiment 3 of this invention. 1 is a block diagram showing an electrical configuration of an electro-optical device (liquid crystal device) to which the present invention is applied. 1 is a cross-sectional view schematically showing a configuration of an electro-optical device to which the present invention is applied. FIG. 10 is a plan view showing a layout for several pixels including nonlinear elements in the electro-optical device shown in FIG. 9. FIG. 10 is an explanatory diagram of nonlinear elements formed in each pixel in the electro-optical device illustrated in FIG. 9. FIG. 10 is a process diagram illustrating a part of an element substrate forming process in the manufacturing process of the electro-optical device illustrated in FIG. 9. It is explanatory drawing which shows the nitrogen distribution in the insulating layer of the conventional nonlinear element.

Explanation of symbols

10, 10x ··· Non-linear element (TFD), 13 ·· Tantalum film, 13b, 13x ·· Lower electrode, 14, 14y ··· Sputtered film, 14b, 14x ··· Insulating layer, 14z ·· Anodized film, 15b 15x ··· Upper electrode, 20 · · Element substrate, 100 · · Electro-optical device

Claims (9)

In a non-linear element including a lower electrode, an insulating layer covering the surface side of the lower electrode, and an upper electrode facing the lower electrode through the insulating layer,
The lower electrode is composed of a nitrogen-containing tantalum film,
The insulating layer is composed of a nitrogen-containing tantalum oxide film containing hydrogen,
In the insulating layer, at least a portion covering the upper surface of the lower electrode is formed of a sputtered film of a nitrogen-containing tantalum oxide film.   In the insulating layer, a portion covering the upper surface of the lower electrode is configured by the sputtered film of the nitrogen-containing tantalum oxide film, and a portion covering the side surface of the lower electrode is configured by the anodic oxide film of the lower electrode. The nonlinear element according to claim 1, characterized in that:   The nonlinear element according to claim 1, wherein the insulating layer is entirely composed of a sputtered film of the nitrogen-containing tantalum oxide film. In a method for manufacturing a nonlinear element comprising a lower electrode, an insulating layer covering the surface side of the lower electrode, and an upper electrode facing the lower electrode through the insulating layer,
A nitrogen-containing tantalum film forming step of forming a nitrogen-containing tantalum film;
A tantalum oxide film sputter forming step of sputter-forming a nitrogen-containing tantalum oxide film on the nitrogen-containing tantalum film;
A lower electrode patterning step of patterning the nitrogen-containing tantalum film together with the nitrogen-containing tantalum oxide film to form the lower electrode;
After the lower electrode patterning step, anodizing with the lower electrode as an anode, and forming a nitrogen-containing tantalum oxide film on the side surface of the lower electrode;
A hydrogen introduction step of introducing hydrogen into the nitrogen-containing tantalum oxide film;
The manufacturing method of the nonlinear element characterized by having.   5. The method of manufacturing a nonlinear element according to claim 4, wherein in the lower electrode patterning step, the nitrogen-containing tantalum film and the nitrogen-containing tantalum oxide film are patterned by dry etching. In a method for manufacturing a nonlinear element comprising a lower electrode, an insulating layer covering the surface side of the lower electrode, and an upper electrode facing the lower electrode through the insulating layer,
A nitrogen-containing tantalum film forming step of forming a nitrogen-containing tantalum film;
A lower electrode patterning step of patterning the nitrogen-containing tantalum film to form the lower electrode;
A tantalum oxide film sputter forming step of sputtering a nitrogen-containing tantalum oxide film on the surface side of the lower electrode;
A hydrogen introduction step of introducing hydrogen into the nitrogen-containing tantalum oxide film;
The manufacturing method of the nonlinear element characterized by having.   The method for manufacturing a nonlinear element according to claim 6, wherein after the tantalum oxide film sputter forming step, an anodic oxidation step of anodizing with the lower electrode as an anode is performed.   8. The method of manufacturing a nonlinear element according to claim 4, wherein a voltage corresponding to a thickness of the sputtered film is applied to the lower electrode in the anodic oxidation step. An electro-optical device using the nonlinear element according to any one of claims 1 to 3,
An electro-optical device comprising: a non-linear element as a pixel switching element in each of a plurality of pixel regions on an element substrate.

Images