JP2005085796A - Nonlinear element, its manufacturing method, electrooptic device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonlinear element that can constitute a high-precision and high-contrast electrooptic device by effectively reducing the area of the element. <P>SOLUTION: The TFD element (nonlinear element) is provided with an effective element section constituted by laminating a lower electrode 14, a second insulating film 182, and an upper electrode 19 upon another. The second insulating film 182 is formed by laminating an oxidation suppressing layer 182a composed of an insulating material nonpermeable of oxygen and an insulating layer 182b upon another, and has a film thickness thinner than that of the first insulating film 181. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a nonlinear element, a method for manufacturing the same, an electro-optical device, and an electronic apparatus.

As a pixel switching element of an active matrix liquid crystal device or the like, one using a non-linear element is known. In this type of liquid crystal device, the ratio of the capacitance of the nonlinear element (element capacitance) and the capacitance of the liquid crystal driven by the nonlinear element greatly affects display characteristics. Therefore, in order to reduce the element capacitance, the element area Various configurations have been studied to reduce the size (for example, Patent Document 1).
JP 7-43749 A

In the manufacturing method described in Patent Document 1, a metal film forming a lower electrode and a resin film or an oxide film covering the metal film are provided on a substrate, and both are patterned into a predetermined shape, and then the resin film and the oxide film are formed. This is a method in which the lower electrode is anodized from the side surface while remaining. However, when the present inventor actually examined the manufacturing method, in the configuration in which the resin film was provided on the lower electrode, the resin film was peeled off, and oxidation progressed to the upper surface of the lower electrode. It became clear that the uniformity of the nonlinear element was reduced. Also, in the method of providing the oxide film on the lower electrode, although the oxide film does not peel off, a cavity is generated at the interface between the oxide film provided on the upper surface and the anodic oxide film formed on the side surface of the lower electrode in the subsequent process It has been clarified that there is a possibility of causing a capacitance leak of the element.
Moreover, in the manufacturing method described in Patent Document 1, at least a step of forming a resin film, an oxide film, or a metal film that functions as a barrier film when oxidizing the lower electrode, and a step of peeling these barrier films Therefore, it is disadvantageous in terms of manufacturing ease and manufacturing cost.

  The present invention has been made in view of the above-described problems of the prior art, and can effectively reduce the element area, and thus can form a high-definition, high-contrast electro-optical device, and the related An object of the present invention is to provide a method capable of manufacturing a nonlinear element with high reproducibility by a simple process.

In order to solve the above-mentioned problem, the present invention is a nonlinear element including a first conductive film, an insulating film, and a second conductive film sequentially stacked on a base material, wherein the insulating film includes the first conductive film A first insulating film that covers a side surface portion of the first conductive film; and a second insulating film that covers an upper surface portion of the first conductive film, wherein the second insulating film is an oxygen-impermeable oxidative inhibition made of an insulating material. Provided is a non-linear element comprising a layer and having a thickness smaller than that of the first insulating film.
In the nonlinear element of this configuration, the thickness of the second insulating film covering the upper surface portion of the first conductive film is made smaller than the film thickness of the first insulating film covering the side surface portion, so that the effective efficiency of the nonlinear element is increased. A simple element portion (a region through which charges penetrate during operation) can be only the upper surface portion of the first conductive film. As a result, the capacity and performance of the element can be reduced, and the side surface portion of the first conductive film is not included in the element area. Therefore, when applied to an electro-optical device or the like including a plurality of nonlinear elements. Thus, it is possible to effectively prevent variations in element characteristics between nonlinear elements.

  In the nonlinear element of the present invention, it is preferable that the second insulating film has a structure in which a plurality of insulating layers are stacked. According to this configuration, the thickness of the second insulating film forming the effective element portion can be easily controlled by the insulating layer thickness laminated together with the oxidation inhibiting layer, and the element capacitance is controlled with high accuracy. A nonlinear element having uniform characteristics can be provided.

  In the nonlinear element of the present invention, the insulating layer constituting the second insulating film may include an insulating layer made of the same constituent material as the first insulating film. According to this configuration, the second insulating film and the first insulating film can be formed by the same oxidation process, and a nonlinear element that can be efficiently manufactured can be provided.

  In the nonlinear element of the present invention, it is preferable that the second insulating film is formed so as to cover an upper surface of the first insulating film and an upper surface of the first conductive film. According to this configuration, the upper surface edge (upper apex portion) of the first conductive film, which is likely to cause capacitance leakage in the nonlinear element, can be reliably covered with the second insulating film, and thus has excellent reliability. Can be provided.

  In the nonlinear element of the present invention, the oxidation suppression layer can be configured to be an insulating nitride or metal oxide. In the nonlinear element of the present invention, the oxidation inhibiting layer can be made of silicon nitride or magnesium oxide.

Next, the present invention provides a method for manufacturing a nonlinear element comprising a first conductive film, an insulating film, and a second conductive film, wherein the first metal film and a single element or an oxide are formed on a substrate. A step of sequentially forming and forming an oxidation inhibition layer made of a material exhibiting oxygen non-permeability and insulation; a step of patterning the first metal film and the oxidation inhibition layer; and the first metal. Forming the first conductive film by partially oxidizing the film, and forming an insulating film having a thickness larger than the oxidation inhibiting layer on a side of the first conductive film; And a step of forming the second conductive film on the layer. A method of manufacturing a nonlinear element is provided.
According to this manufacturing method, since the oxidation inhibiting layer is provided on the first metal film, in the subsequent oxidation step, the first metal film is not oxidized from the upper side but is oxidized from the side. Accordingly, the first conductive film (the metal film that remains without being oxidized) having the insulating films on both sides can be positively formed with high accuracy in the central region of the first metal film. In addition, since the oxidation inhibiting layer is made of a single substance or a material that exhibits insulation by oxidation, it functions as an insulating film that constitutes an effective element portion of the nonlinear element on the upper surface of the first conductive film. Therefore, according to this manufacturing method, it is possible to manufacture a non-linear element in which an effective element portion is formed only on the upper surface of the first conductive film by a very simple process.
Further, in this manufacturing method, since the first metal film is oxidized only from the side, it is easy to make the first conductive film finer beyond the patterning accuracy, the device capacitance is small, and the high-performance non-linearity. It is extremely effective as a device manufacturing method.

In the manufacturing method of this invention, the process of forming a 2nd metal film on the said oxidation suppression layer can also be further provided.
According to this manufacturing method, since the oxidation treatment is performed on the laminated film in which the oxidation preventing layer is provided on the first metal film and the second metal film is provided on the upper side, the second metal film is oxidized. Thus, the oxidation proceeding to the first metal film side can be stopped by the oxidation inhibiting layer. As a result, the first metal film is oxidized only from the side to form a first conductive film in which insulating films are arranged on both sides. The second metal film is entirely oxidized to form an insulating film that covers the upper surface of the first conductive film together with the oxidation suppression layer. In the nonlinear element thus manufactured, the effective insulating film of the element portion is an insulating film formed by oxidizing the oxidation suppression layer and the second metal film. Therefore, the element characteristics can be controlled by the film thickness of the second metal film, and this is an effective manufacturing method used when, for example, the insulating film thickness of the element portion is insufficient with only the oxidation suppression layer.

  In the manufacturing method according to the present invention, the oxidation-inhibiting layer is formed of a material having oxygen impermeability and insulation, or a metal material exhibiting oxygen impermeability and insulation by forming an oxide. Can do.

  In the manufacturing method according to the present invention, the oxidation step is preferably performed by an anodic oxidation treatment. According to this manufacturing method, the quality of the insulating film formed by oxidation of the first metal film and the second metal film can be improved, and the first metal film and the second metal film provided at different positions can be improved. Thus, the non-linear element can be manufactured efficiently.

  Next, an electro-optical device of the present invention includes the above-described nonlinear element of the present invention. According to this configuration, an electro-optical device that has a small element capacity and includes a high-performance nonlinear element as a switching element and can display with high definition and high contrast is provided.

  Next, an electronic apparatus according to the invention includes the electro-optical device according to the invention described above. According to this configuration, an electronic apparatus including a high-definition and high-contrast display unit is provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Configuration of liquid crystal device)
FIG. 1 is a block diagram showing an electrical configuration of a liquid crystal device which is an example of an electro-optical device according to the invention. The liquid crystal device shown in the figure is an active matrix liquid crystal device using a TFD (Thin Film Diode) element (two-terminal nonlinear element) as a switching element. The liquid crystal device includes a plurality of scanning lines 25 extending in the X direction, a plurality of data lines 11 extending in the Y direction, and subpixels 50 provided at each intersection of the scanning lines 25 and the data lines 11. Have Further, among the plurality of scanning lines 25, the odd-numbered scanning lines 25 counted from the top in FIG. 1 (hereinafter simply referred to as “odd-numbered scanning lines”) are connected to the first Y driver IC 401, The even-numbered scanning lines 25 (hereinafter simply referred to as “even-numbered scanning lines”) counted from the top in FIG. 1 are connected to the second Y driver IC 402. The scanning signal generated by these Y driver ICs is supplied to each scanning line 25.

  Hereinafter, the first Y driver IC 401 and the second Y driver IC 402 are simply referred to as “Y driver IC 40” when it is not necessary to distinguish between them. Each data line 11 is connected to an X driver IC 41, and a data signal generated by the X driver IC 41 is supplied. On the other hand, each of the plurality of sub-pixels 50 arranged in a matrix corresponds to one of R (red), G (green), and B (blue). Each sub-pixel 50 has a configuration in which a liquid crystal display element 51 and a TFD element 13 are connected in series.

Next, FIG. 2 is a perspective view showing a configuration when the liquid crystal device according to the present embodiment is viewed from the back side (that is, the side opposite to the side where the observer should be positioned). As shown in FIG. 2, the negative direction of the X axis is defined as “A side” and the positive direction is defined as “B side”.
As shown in FIG. 2, in the liquid crystal device, an element substrate (support substrate) 10 and a counter substrate (other substrate) 20 that face each other are bonded together by a sealing material 30 and surrounded by both the substrates and the sealing material 30. A liquid crystal (not shown in FIG. 2), which is an electro-optical material, is sealed in the region. The sealing material 30 is formed in a substantially rectangular frame shape along the edge of the counter substrate 20, but has a shape in which a part is opened to enclose the liquid crystal. For this reason, the opening is sealed with the sealing material 31 after the liquid crystal is sealed.

  The sealing material 30 has a large number of conductive particles dispersed therein. The conductive particles are, for example, plastic particles plated with metal or conductive resin particles. The conductive particles are electrically connected to each other on the element substrate 10 and the counter substrate 20. It also functions as a spacer that keeps the gap (cell gap) between the substrates constant. Actually, a polarizing plate for polarizing incident light, a retardation plate for compensating for interference colors, and the like are appropriately attached to the outer surfaces of the element substrate 10 and the counter substrate 20.

  The element substrate 10 and the counter substrate 20 are light-transmitting plate-like base materials such as glass, quartz, and plastic. Among these, the plurality of data lines 11 described above are formed on the inner surface (opposite substrate 20 side) surface of the element substrate 10 located on the observation side, while the inner side (element substrate 10 side) of the counter substrate 20 located on the back side. A plurality of scanning lines 25 are formed on the surface. In addition, the element substrate 10 has an area outside the sealing material 30 (that is, an area that does not face the sealing material 30 and the liquid crystal; hereinafter, referred to as an “edge area”) 10 a. The X driver IC 41 is located near the center of the edge region 10a in the X direction, and the first Y driver IC 401 and the second Y driver IC 402 are located on both sides of the X driver IC 41, respectively. It is implemented using. That is, these driver ICs are mounted on the element substrate 10 via an anisotropic conductive film (ACF) in which conductive particles are dispersed in an adhesive. Further, a plurality of pads 17 are formed in the vicinity of the edge of the element substrate 10 in the edge region 10a, and one end of a flexible substrate (not shown) is bonded in the vicinity of the portion where the pads 17 are formed. Is done. An external device such as a circuit board is joined to the other end of the flexible board.

  Under such a configuration, the X driver IC 41 generates a data signal according to a signal input from an external device via the flexible substrate and the pad 17, and outputs the data signal to the data line 11. On the other hand, the Y driver ICs 401 and 402 generate and output a scanning signal in accordance with a signal input from an external device via the flexible substrate and the pad 17. This scanning signal is transmitted from the routing wiring 16 formed on the element substrate 10 to the counter substrate 20 side through the conductive particles in the sealing material 30, and is applied to each scanning line 25 on the upper substrate 20.

  Next, a configuration of a region (hereinafter referred to as “display region”) surrounded by the inner peripheral edge of the sealing material 30 in the liquid crystal device will be described. FIG. 3 is a diagram showing a portion in the display area of the cross section taken along line C-C ′ in FIG. 2. 4A is a plan configuration diagram showing one sub-pixel region of the liquid crystal device according to the present embodiment, and FIG. 4B is an enlarged view of the TFD element 13 shown in FIG. FIG. 4C is a cross-sectional configuration diagram taken along the line DD ′ shown in FIG. 4B.

  As shown in FIG. 3, the liquid crystal device according to the present embodiment is sealed in a region sandwiched between the element substrate 10 and the counter substrate 20 that are arranged to face each other and the substrates 10 and 20. The liquid crystal 35 is provided. A plurality of pixel electrodes 12 arranged in a matrix and a plurality of pixel electrodes 12 extending in the Y direction on the inner surface (on the liquid crystal 35 side) surface of the element substrate 10 in the display region shown in FIG. Data lines 11 are formed. Each pixel electrode 12 is a substantially rectangular electrode in plan view formed of a transparent conductive material such as ITO (Indium Tin Oxide). Each pixel electrode 12 and the data line 11 adjacent to the pixel electrode 12 on one side are connected via a TFD element (not shown) (see FIG. 4A). Further, as shown in FIG. 3, the surface of the element substrate 10 on which the data lines 11, the pixel electrodes 12, and the TFD elements are formed is covered with an alignment film 151. The alignment film 151 is an organic thin film made of polyimide or the like, and is subjected to a rubbing process for defining the alignment direction of the liquid crystal 35 when no voltage is applied.

  Here, as shown in FIG. 4A, when a region corresponding to one sub pixel 50 among the elements on the element substrate 10 is viewed from the counter substrate 20 side (back side), the pixel having a substantially rectangular shape in a plan view. A data line 11 is formed so as to extend along the long side direction of the electrode 12. As shown in the enlarged plan view of FIG. 4B, the TFD element 13 includes a lower electrode (first conductive film) 14 having a rectangular shape in plan view and extending substantially parallel to the data line 11, and the lower electrode 14 The first insulating film 181 formed on the side surface of the first electrode, the second insulating film 182 formed on the upper surface of the lower electrode 14, and the first insulating film 181 and 182 formed on the insulating films 181 and 182 are spaced apart from each other. An upper electrode (second conductive film) 11 a and a second upper electrode (second conductive film) 19 are included. As shown in FIG. 4A, the first upper electrode 11a is formed by extending a part of the data line 11 toward the pixel electrode 12, and the second upper electrode 19 is formed by the lower electrode. The TFD element 13 and the pixel electrode 12 are electrically connected so as to partially overlap the pixel electrode 12 at the end opposite to the pixel 14.

  The TFD element 13 includes a first TFD element 131 and a second TFD element 132. That is, the first TFD element 131 is formed in a region facing the first upper electrode 11a via the insulating films 181 and 182 in the planar region of the lower electrode 14, and the insulating films 181 and 182 are interposed therebetween. A second TFD element 132 is formed in a region facing the second upper electrode 19.

The second TFD element 132 will be described in more detail. As shown in FIG. 4C, the TFD element 132 is provided on the base insulating film 4 formed on the element substrate 10. A lower electrode 14 and first insulating films 181 and 181 covering the side surfaces 14b and 14b of the lower electrode 14 are formed on the base insulating film 4, and the upper surface 14a of the lower electrode 14 and the first insulating film 181 are formed. , 181 is covered with a second insulating film 182. And, as a result of adopting a metal / insulator / metal sandwich structure in a region where the second upper electrode 19 and the lower electrode 14 face each other through the second insulating film 182, the diode switching characteristics in both positive and negative directions A TFD element 132 having the structure is configured. Therefore, the element portion of the TFD element 132 according to the present embodiment is formed in a region where the upper surface 14a of the lower electrode 14 and the upper electrode 19 substantially overlap in a plane.
Although not shown, the first TFD element 131 has a configuration in which the first upper electrode 11a is arranged in place of the upper electrode 19 in the cross-sectional structure shown in FIG.

  In the case of the present embodiment, the second insulating film 182 has a structure in which an oxidation suppression layer 182a and an insulating layer 182b are stacked from the lower electrode 14 side. The oxidation inhibition layer 182a is formed of an insulating nitride such as silicon nitride or a non-oxygen permeable insulating material such as MgO. In the manufacturing process of the TFD element 13, the upper surface 14a side of the lower electrode 14 is oxidized. This is a layer provided to prevent the occurrence of the damage (details will be described in the later production method). The insulating layer 182b can be formed using an insulating material such as tantalum oxide as in the case of the first insulating film 181, and can be formed in the same step as the first insulating film 181.

  FIG. 4 illustrates the case where the second insulating film 182 has a stacked structure of the oxidation inhibiting layer 182a and the insulating layer 182b. However, the insulating layer 182b is not provided, and the oxidation inhibiting layer 182a alone is used to form the TFD element 13. An effective element part can also be comprised. Alternatively, since the insulating layer 182b can adjust different insulating film thickness depending on the characteristics of the TFD element 13, there is an advantage that the TFD element 13 having an arbitrary insulating film thickness can be easily manufactured.

  The film thickness of the second insulating film 182 covering the upper surface 14a of the lower electrode 14 (that is, the sum of the film thickness of the oxidation inhibiting layer 182a and the film thickness of the insulating layer 182b) is the first insulating film covering the side surface 14b of the lower electrode 14. The film thickness is preferably ½ or less of the film 181. Specifically, the second insulating film 182 has a thickness of about 10 to 30 nm, and the first insulating film 181 has a film thickness of 30. It is preferable that it is about ~ 300 nm. The film thickness of the second insulating film 182 that forms the element capacitance of the TFD element 13 is set according to the element characteristics of the TFD element 13, and the first insulating film 181 does not form the element capacitance of the TFD element. It is formed to a thickness that does not cause charge penetration in the region.

In the TFD element 13 according to the present embodiment, the first TFD element 131 and the second TFD element 132 are formed on the lower electrode 14 so as to be separated from each other. Has opposite diode switching characteristics. Thus, since the TFD element 13 has a configuration in which two diodes are connected in series in opposite directions, the current-voltage nonlinear characteristic is bi-directional with positive and negative in comparison with the case where one diode is used. Symmetrized over.
However, in order to ensure the symmetry of such nonlinear characteristics, the thickness of the second insulating film 182 constituting the first TFD element 131 and the thickness of the second insulating film 182 constituting the second TFD element 132 And the areas of the upper electrodes 11a and 19 in the region facing the lower electrode 14 through the second insulating film 182 must be made equal to each other. In the present embodiment, as shown in FIG. 4B, the second insulating film 182 is formed to extend with substantially the same width along the length direction of the lower electrode 14, so that the upper electrode If 11a and 19 are formed to have the same width, the symmetry of the TFD elements 131 and 132 can be easily obtained.

The lower electrode 14 is formed of various conductive materials such as tantalum (Ta) alone or an alloy containing tantalum as a main component. The data line 11 (including the first upper electrode 11a) and the second upper electrode 19 are formed of the same layer made of various conductive materials such as chrome (Cr) and aluminum (Al), for example, In addition to a metal material, tantalum or molybdenum (Mo) can be used.
Further, the base insulating film 4 provided on the lower side of the lower electrode 14 can be formed of, for example, tantalum oxide or the like, and the lower electrode 14 can function as an adhesion layer for fixing the substrate 10.

On the other hand, as shown in FIG. 3, a reflective layer 21, a color filter 22, a light shielding layer 23, an overcoat layer 24, a plurality of scanning lines 25 and an alignment film 26 are formed on the surface of the counter substrate 20.
The reflective layer 21 is a thin film formed of a metal having light reflectivity such as aluminum or silver. Light incident on the liquid crystal device from the observation side is reflected on the surface of the reflection layer 21 and emitted to the observation side, thereby realizing a so-called reflection type display. Here, as shown in FIG. 3, the region covered with the reflective layer 21 on the inner surface of the counter substrate 20 is a rough surface on which a large number of fine irregularities are formed. Therefore, fine irregularities (that is, scattering structures) reflecting the rough surface are formed on the surface of the reflective layer 21 formed in a thin film so as to cover the rough surface. As a result, incident light from the observation side is reflected in a state of being appropriately scattered on the surface of the reflective layer 21, and a specular reflection on the surface of the reflective layer 21 is avoided to realize a wide viewing angle.

Further, if an opening region where the reflective layer 21 is not partially formed is provided in the planar region of the pixel electrode 12 shown in FIG. 4A, transmissive display through the opening region becomes possible, and transflective Type liquid crystal device can be constructed.
Note that FIG. 3 illustrates a case where the uneven shape is directly formed on the surface of the substrate 20, but the structure for imparting the scattering function to the reflective layer 21 is not limited to the example given in this embodiment. For example, a resin film is formed on the substrate 20 and irregularities are formed on the surface thereof, or an optical element having light scattering properties on the reflective layer 21 (a resin film obtained by kneading and curing materials having different refractive indexes) Of course, it is also possible to apply the one provided with.

The color filter 22 is a resin layer formed on the surface of the reflective layer 21 corresponding to each sub-pixel 50, and any of R (red), G (green), and B (blue) depending on the dye or pigment. It is colored crab. A pixel (dot) of the display image is configured by the three sub-pixels 50 corresponding to different colors. The light shielding layer 23 is formed in a lattice shape corresponding to the gaps between the pixel electrodes 12 arranged in a matrix on the element substrate 10, and plays a role of shielding the gaps between the pixel electrodes 12.
As shown in FIG. 3, the light shielding layer 23 in the present embodiment has a configuration in which color filters 22 for three colors of R, G, and B are laminated. The overcoat layer 24 is a layer for flattening the unevenness formed by the color filter 22 and the light shielding layer 23, and is formed of, for example, an epoxy or acrylic resin material.

The scanning line 25 is a belt-like electrode formed on the surface of the overcoat layer 24 by a transparent conductive material such as ITO. Each scanning line 25 is formed to extend in the X direction in the figure so as to face the plurality of pixel electrodes 12 that are arranged in the X direction on the element substrate 10. Then, the liquid crystal display element 51 shown in FIG. 1 is configured by the pixel electrode 12, the scanning line 25 opposed to the pixel electrode 12, and the liquid crystal 35 sandwiched therebetween.
That is, when a voltage higher than the threshold is applied to the TFD element 13 by supplying a scanning signal to the scanning line 25 and supplying a data signal to the data line 11, the TFD element 13 is turned on. As a result, charges are accumulated in the liquid crystal display element 51 connected to the TFD element 13, and the alignment direction of the liquid crystal 35 changes. Thus, the desired display is performed by changing the orientation direction of the liquid crystal 35 for each sub-pixel 50. On the other hand, even if the TFD element 13 is turned off after the charge is accumulated, the charge accumulation in the liquid crystal display element 51 is maintained. Further, the surface of the overcoat layer 24 on which the plurality of scanning lines 25 are formed is covered with an alignment film 26 similar to the alignment film 151 on the element substrate 10.

  In the liquid crystal device of the present embodiment having the above configuration, as shown in FIG. 4, in the TFD element 13, the first insulating film 181 and the second insulating film 182 are formed so as to cover the lower electrode 14, and the lower electrode 14. Since the second insulating film 182 covering the upper surface 14a of the lower electrode 14 is formed thinner than the first insulating film 181 covering the side surface 14b of the lower electrode 14, the upper surface 14a of the lower electrode 14 via the second insulating film 182; The element capacitances of the TFD elements 131 and 132 are formed in a region where the upper electrode 11a or the upper electrode 19 overlaps in a planar manner. As a result, the side surface 14b of the lower electrode 14 is not included in the effective element area of the TFD elements 131 and 132. Therefore, variation in characteristics of the TFD element 13 in the element substrate 10 surface can be effectively suppressed, and high definition and high image quality can be achieved. A liquid crystal device capable of displaying the above is obtained.

As shown in FIG. 4C, the second insulating film 182 covers the upper surface 14a of the lower electrode 14 and the upper surface of the first insulating film 181 and has a uniform film thickness. Yes. With this configuration, it is possible to effectively prevent capacitance leakage at the upper apex portion of the lower electrode 14 and to obtain excellent reliability.
As described above, according to the present invention, it is possible to reduce the effective element area while maintaining the in-plane uniformity of the TFD element provided in each pixel of the electro-optical device including the liquid crystal device. The present invention is a technique particularly suitable for use in an active matrix liquid crystal device including the TFD element exemplified in the above embodiment.

(Manufacturing method of liquid crystal device)
Next, a method for manufacturing a liquid crystal device will be described with reference to the drawings.
According to the manufacturing method of the present invention, the TFD element 13 according to the above embodiment can be accurately formed, and even when the element area is reduced due to the higher definition of the pixel, the element characteristics vary. A liquid crystal device capable of obtaining a high-quality display without any problems can be manufactured. Hereinafter, as an embodiment of a method for manufacturing an electro-optical device (and a two-terminal nonlinear element) according to the present invention, a method for manufacturing the liquid crystal device of the previous embodiment will be described with reference to FIG.

FIG. 5 is a cross-sectional process diagram illustrating a manufacturing process of the liquid crystal device according to the present embodiment.
First, as shown in FIG. 5 (a), a support substrate 10 having translucency such as glass or plastic is prepared. The support substrate 10 should form the element substrate 10 shown in FIGS. 2 to 4 through the respective steps according to the present embodiment. Then, after the base insulating film 4 made of tantalum oxide is formed on the support substrate 10, the first metal film 114 made of tantalum, the oxidation inhibiting layer 282a made of magnesium, and the tantalum are made on the base insulating film 4. The second metal film 282b is sequentially stacked using a sputtering method or the like.

Next, as shown in FIG. 5B, the first metal film 114, the oxidation inhibition layer 282a, and the second metal film 282b are patterned into a predetermined shape using a known photolithography technique.
Next, as shown in FIG. 5C, anodization is performed using the first metal film 114 and the second metal film 282b on the support substrate 10 as anodes. By this anodic oxidation process, the side portion of the first metal film 114 is oxidized to form the first insulating film 181, and the lower electrode 14 is formed to the portion of the first metal film 114 that is not oxidized. Further, the second metal film 282b having a relatively small thickness is entirely oxidized to become the insulating layer 182b.

  Here, since the oxidation inhibiting layer 282a is provided between the first metal film 114 and the second metal film 282b, the oxidation of the metal film proceeding from the outside of these laminated films is caused by the oxidation inhibiting layer 282a. Is stopped at the position of the oxidation inhibiting layer 182a formed by the oxidation of magnesium constituting the. As a result, the upper surface 14a of the lower electrode 14 in contact with the oxidation inhibiting layer 182a is held in a substantially unoxidized state, and the oxidation in the first metal film 114 proceeds only in the lateral direction, and as a result, the lower electrode having a predetermined planar dimension 14 is formed.

  In the present embodiment, since the first metal film 114 is made of tantalum, the first insulating film 181 is tantalum oxide. As shown in FIG. 4C, the first insulating film 181 is formed to have a layer thickness that can ensure insulation between the upper electrodes 11a and 19 and the lower electrode 14 in the operating voltage range of the TFD element 13. The second insulating film 182 that forms an effective element portion is formed thinner than the first insulating film 181, and the layer thickness is set according to the characteristics of the TFD element to be manufactured.

In this embodiment, a magnesium film is used as the oxidation suppression layer 282a. However, the oxidation suppression layer 282a may be formed of an insulating nitride film such as silicon nitride. In this case, the progress of oxidation is stopped by the nitride film itself, instead of forming an oxide like magnesium and stopping the diffusion of oxygen.
Furthermore, as the oxidation inhibiting layer 282a, any material having non-oxygen permeability (characteristics that inhibit oxygen diffusion) as a single substance or an oxide can be applied without any problem. When a metal material is used, tantalum or aluminum It is considered that the present invention can be applied to any metal material excluding the valve metal. Further, when the metal oxide of the oxidation inhibiting layer is formed by anodic oxidation as in this embodiment and the progress of the anodic oxidation is stopped, the constituent material of the oxidation inhibiting layer 282a is a metal having a high affinity with oxygen. It is preferable to use a material.

Subsequently, as shown in FIG. 5D, the upper electrode 19 made of chromium is patterned so as to partially cover the first insulating film 181 and the second insulating film 182, so that the TFD of this embodiment is formed. Element 132 is obtained. The cross-sectional structure shown in FIG. 5 (d) corresponds to the cross-sectional structure along the line DD 'shown in FIG. 4 (b). In practice, the data line 11 is also formed when the pattern of the upper electrode 19 is formed. A pattern is formed at the same time.
Next, as shown in FIG. 4A, the pixel electrode 12 made of a transparent conductive material such as ITO is formed so as to partially ride on one end side (the side opposite to the lower electrode 14) of the second upper electrode 19. If the alignment film 151 covering these constituent members is formed, the element substrate 10 shown in FIG. 2 is obtained. In forming the upper electrodes 19 and 11a and the data line 11, it is possible to apply a patterning method using a photolithography technique by forming a metal film by a film forming method such as a sputtering method.

  Then, the element substrate 10 obtained through the manufacturing process according to the manufacturing method of the present embodiment is bonded to the counter substrate 20 separately manufactured by a known manufacturing method and the sealing material 30 as shown in FIG. In addition, the liquid crystal device of the previous embodiment is obtained by sealing the liquid crystal in a space between the sealing material 30 and the two substrates 10 and 20.

  Thus, according to the manufacturing method according to the present embodiment, the second insulating film 182 having a thinner layer thickness than the first insulating 181 covering the side surface 14b of the lower electrode 14 is formed on the upper surface 14a of the lower electrode 14. The TFD element 13 can be formed by a simple process. In particular, by providing the oxidation inhibiting layer 282a (182a) and stopping the anodic oxidation from the information of the first metal film 114 at the position where the oxidation inhibiting layer 282a is formed, it is possible to reduce the size with high accuracy. The electrode 14 can be formed, and the film thickness of the second insulating film 182 constituting the effective element portion of the TFD element 13 is determined by the film thickness of the second metal film 282b stacked on the oxidation suppression layer 282a. Can be easily controlled. Therefore, according to the manufacturing method of the present embodiment, it is possible to easily and highly accurately manufacture a TFD element having a small capacity, which includes the lower electrode 14 that is miniaturized exceeding the patterning accuracy.

  If the manufacturing method according to this embodiment is used, the second insulating film 182 can be accurately formed on the upper surface 14a of the lower electrode 14 by the above process even if the lower electrode 14 is miniaturized. At the same time, since the effective element area of the TFD element 13 does not include the tapered portion 14b of the lower electrode 14, the dimensional accuracy of the effective element area can be improved, and thus the TFD element 13 in the element substrate 10 plane can be improved. The variation in device characteristics can be effectively suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. The nonlinear element and the manufacturing method thereof according to the present invention are applied to a liquid crystal device. The present invention can be applied to various methods of manufacturing electro-optical devices that are not limited. For example, it can be suitably used for an EL (electroluminescence) device, an electrophoresis device, a device using plasma emission or fluorescence by electron emission (for example, PDP, FED, SED), a manufacturing method thereof, or the like.

(Electronics)
FIG. 6 is a perspective configuration diagram illustrating an example in which the electro-optical device according to the invention is applied to a display unit of a mobile phone. As shown in the figure, a cellular phone 1300 includes the liquid crystal device (electro-optical device) of the above-described embodiment as a small-sized display unit 1301, and includes a plurality of operation buttons 1302, an earpiece 1303, and a mouthpiece 1304. Configured.
The liquid crystal device of the above embodiment is not limited to the mobile phone, but an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, It can be suitably used as an image display means for calculators, word processors, workstations, videophones, POS terminals, devices equipped with touch panels, etc., and any electronic device can provide high-definition and high-contrast display. it can.

FIG. 1 is a circuit block diagram of a liquid crystal device according to an embodiment. FIG. 2 is a perspective configuration diagram showing the external appearance. FIG. 3 is a cross-sectional configuration diagram taken along line C-C ′ of FIG. 2. 4A is a plan view of the pixel region of the liquid crystal device, FIG. 4B is an enlarged plan view of the TFD element, and FIG. 4C is a cross-sectional view taken along line D-D ′ of FIG. FIG. 5 is a sectional process diagram of the manufacturing method according to the embodiment. FIG. 6 is a perspective configuration diagram illustrating an example of an electronic apparatus according to the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Element board | substrate, 11 ... Data line, 11a ... 1st upper electrode (2nd electrically conductive film), 12 ... Pixel electrode, 13 ... TFD element (two terminal type nonlinear element), 14 ... Lower electrode (1st electrically conductive film) , 19 ... second upper electrode (second conductive film), 20 ... counter substrate, 114 ... first metal film, 181 ... first insulating film, 182 ... second insulating film, 182a ... oxidation inhibiting layer, 182b ... Insulating layer, 282a ... Oxidation inhibiting layer, 282b ... second metal film

Claims (12)

A non-linear element comprising a first conductive film, an insulating film, and a second conductive film sequentially stacked on a substrate,
The insulating film includes a first insulating film that covers a side surface portion of the first conductive film, and a second insulating film that covers an upper surface portion of the first conductive film,
The non-linear element, wherein the second insulating film is configured to include an oxygen non-permeable oxidation inhibiting layer made of an insulating material, and is formed to be thinner than the first insulating film.   The nonlinear element according to claim 1, wherein the second insulating film has a structure in which a plurality of insulating layers are stacked.   The nonlinear element according to claim 2, wherein the insulating layer constituting the second insulating film includes an insulating layer made of the same constituent material as the first insulating film.   4. The nonlinear element according to claim 1, wherein the second insulating film is formed to cover an upper surface of the first insulating film and an upper surface of the first conductive film. 5.   4. The nonlinear element according to claim 1, wherein the oxidation suppression layer is an insulating nitride or metal oxide. 5.   The nonlinear element according to claim 4, wherein the oxidation inhibiting layer is silicon nitride or magnesium oxide. A method of manufacturing a non-linear element comprising a first conductive film, an insulating film, and a second conductive film,
On the substrate, a step of sequentially forming a first metal film and an oxidation inhibiting layer made of a material exhibiting oxygen impermeability and insulation by forming a simple substance or an oxide,
Patterning the first metal film and the oxidation inhibiting layer;
Forming the first conductive film by partially oxidizing the first metal film, and forming an insulating film having a thickness larger than that of the oxidation inhibiting layer on a side of the first conductive film; When,
Forming the second conductive film on the oxidation inhibiting layer;
A method for manufacturing a non-linear element, comprising:   The method for manufacturing a nonlinear element according to claim 7, further comprising a step of forming a second metal film on the oxidation inhibiting layer.   9. The oxidation inhibiting layer is formed of a material having oxygen impermeability and insulation, or a metal material exhibiting oxygen impermeability and insulation by forming an oxide. The manufacturing method of the nonlinear element of description.   The method for manufacturing a nonlinear element according to claim 7, wherein the oxidation step is performed by an anodic oxidation process.   An electro-optical device comprising the nonlinear element according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 11.

Images