JP2008134274A - Method for manufacturing liquid crystal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal device by which an inorganic alignment layer can be efficiently formed on a substrate at a low cost and high mass-productivity and reliability without separately preparing a special manufacturing apparatus. <P>SOLUTION: The method includes: an oxide film forming step of forming an oxide film 150 on a pixel electrode 9a of a TFT substrate; an oxide film etching step of etching the oxide film 150 to form a plurality of island-like portions having a form of stripes in a plan view and a rectangular cross-sectional form; and an inorganic alignment layer forming step of forming an inorganic alignment layer 16 of alignment layers on the pixel electrode 9a by using high-density plasma CVD so as to cover the oxide film 150 in a plan view. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal device, in which an alignment film for aligning liquid crystals interposed between a first substrate and a second substrate is formed on a first substrate and a second substrate that are arranged to face each other. .

  As is well known, for example, a light transmission type liquid crystal device is configured by interposing a liquid crystal between two substrates made of a glass substrate, a quartz substrate or the like.

  In addition, in a liquid crystal device, switching elements such as thin film transistors (hereinafter referred to as TFTs) and pixel electrodes are arranged in a matrix on one substrate, and a counter electrode is arranged on the other substrate. By changing the optical response of the liquid crystal layer interposed between the substrates according to the image signal, it is possible to display an image.

  In addition, the TFT substrate on which the TFT is disposed and the counter substrate disposed to face the TFT substrate are manufactured separately. The TFT substrate and the counter substrate are configured, for example, by laminating a semiconductor thin film, an insulating thin film, or a conductive thin film having a predetermined pattern on a quartz substrate. Each layer is formed by repeating a film forming process and a photolithography process for various films.

  The TFT substrate and the counter substrate thus formed are bonded with high accuracy (for example, within an alignment error of 1 μm) in the panel assembly process. An example of this panel assembling process will be described. First, liquid crystal molecules are aligned along the substrate surface on the surfaces of the TFT substrate and the counter substrate, which are manufactured in the manufacturing process of each substrate, in contact with each liquid crystal layer. For example, an organic alignment film made of polyimide is formed. Thereafter, baking is performed, and further, a rubbing treatment for determining the alignment of liquid crystal molecules when no voltage is applied, that is, a known pretilt angle, is performed on the alignment film.

  Next, when the liquid crystal is interposed between the TFT substrate and the counter substrate by, for example, a liquid crystal sealing method, a sealing material serving as an adhesive is partially formed on one of the TFT substrate and the counter substrate. It is applied in a substantially circumferential shape so as to have a notch serving as an inlet, and this sealing material is used to attach the counter substrate to the TFT substrate.

  Next, after alignment and curing by pressure bonding, a prescribed amount of liquid crystal is dropped in the vicinity of the inlet of the sealing material of the TFT substrate under vacuum, and then released to the atmosphere, thereby opening the inlet. Then, liquid crystal is injected between the TFT substrate and the counter substrate, and finally, the injection port is sealed with a sealing material to manufacture a liquid crystal device.

Incidentally, in recent years, a configuration using an inorganic alignment film made of SiO ₂ or the like, which does not require a rubbing process for aligning liquid crystals, is well known as an alignment film used in a liquid crystal device.

  The inorganic alignment film is formed by being deposited on the target substrate at a predetermined angle corresponding to the pretilt angle, so that the pretilt angle of the liquid crystal can be defined without forming a rubbing treatment after the formation. Such a method for forming an inorganic alignment film is referred to as oblique vapor deposition. Therefore, when an inorganic alignment film is used in a liquid crystal device, the inorganic alignment film does not require rubbing treatment, so that generation of static electricity and dust associated with rubbing treatment can be prevented, and light deterioration due to light transmission may occur. The reliability of the liquid crystal device can be improved. Such a method for forming an inorganic alignment film is disclosed in Patent Document 1, for example.

Patent Document 1 discloses a method of forming an inorganic alignment film by using a sputtering method which is a part of the oblique deposition method. Specifically, the method is provided so as to face a substrate to be formed. The target composed of the same material as the inorganic alignment film to be formed is irradiated with an ion beam to extract the sputtered particles, and then the sputtered particles are perpendicular to the formation surface of the substrate on which the inorganic alignment film is formed. A method of forming an inorganic alignment film by irradiating the formation surface from a direction inclined by a predetermined angle is disclosed.
Japanese Patent Laying-Open No. 2005-84146

  However, in the inorganic alignment film forming method and other oblique deposition methods disclosed in Patent Document 1, in addition to the film forming apparatus usually used for forming a semiconductor thin film, an insulating thin film or a conductive thin film, an inorganic alignment film is used. For the formation of the film, a large apparatus including an ion beam source, a target, a folder for holding a substrate, a vacuum chamber, a gas supply source, an exhaust pump, etc. must be prepared separately, which increases the manufacturing cost. there were.

  In addition, in mass production, it is difficult to stably deposit all inorganic alignment films at a certain angle on the formation surface of each substrate to be manufactured, that is, reliability in manufacturing decreases. There was also a problem that the yield decreased.

  The present invention has been made paying attention to the above-mentioned problems, and it is possible to efficiently form an inorganic alignment film on a substrate at low cost and with high productivity and reliability without separately preparing a special manufacturing apparatus. It is an object to provide a method for manufacturing a liquid crystal device that can be formed.

  In order to achieve the above object, a method of manufacturing a liquid crystal device according to the present invention includes a first substrate and a second substrate that are disposed opposite to each other, and is interposed between the first substrate and the second substrate. A method of manufacturing a liquid crystal device for forming an alignment film for aligning liquid crystal, wherein oxidation is performed on an electrode for applying a driving voltage to the liquid crystal on at least one of the first substrate and the second substrate. An oxide film forming step of forming a film; an oxide film etching step of forming the oxide film by etching on a plurality of islands having a stripe shape in a plan view and a rectangular cross-sectional shape; and the electrode And an inorganic alignment film forming step of forming the inorganic alignment film by using high-density plasma CVD so as to cover the oxide film in a plan view. To do.

  According to the present invention, an inorganic alignment film is used for forming various thin films on a substrate on an oxide film formed on a plurality of islands having a rectangular cross-sectional shape, and is excellent in mass productivity and reliability. By forming by high-density plasma CVD, the inorganic alignment film is formed on the electrode of at least one of the first substrate and the second substrate due to the shape of the plurality of rectangular oxide films. It is formed with a set angle as in the case of forming by conventional oblique deposition. As a result, an inorganic alignment film can be formed on the electrode of at least one of the first substrate and the second substrate without using a special apparatus, and the cost and mass productivity and reliability can be reduced as compared with the prior art. It has the effect that it can be made high and can be formed efficiently.

  In addition, after the oxide film etching step, a tapered surface is formed on each side surface of the oxide film formed on a plurality of island portions having a rectangular cross-section before the inorganic alignment film forming step. And a taper surface forming step.

  According to the present invention, mass-productivity and reliability are used when an inorganic alignment film is formed on various oxide films formed on a plurality of islands each having a tapered surface on one side surface. By forming the high-density plasma CVD excellent in the inorganic alignment film, the inorganic alignment film is formed on at least one of the first substrate and the second substrate due to the shape of the plurality of oxide films each having a tapered surface. On the electrode, a part is formed with an angle of a tapered surface as in the case of forming by conventional oblique deposition. As a result, an inorganic alignment film used for vertical alignment can be formed on the electrode of at least one of the first substrate and the second substrate at a lower cost and mass productivity without using a special apparatus. In addition, there is an effect that it can be formed efficiently with high reliability.

  Further, the taper surface forming step is performed by wet etching.

  The tapered surface forming step is performed by dry etching.

  The present invention has an effect that a tapered surface can be reliably formed on each side surface of a plurality of island-shaped oxide films.

  Embodiments of the present invention will be described below with reference to the drawings. In the embodiments described below, the liquid crystal device will be described by taking a light transmission type liquid crystal device as an example.

  In addition, one of the pair of substrates opposed to each other in the liquid crystal device is an element substrate (hereinafter referred to as a TFT substrate) which is a first substrate, and the other substrate is a first substrate facing the TFT substrate. The counter substrate, which is the second substrate, will be described as an example.

(First embodiment)
First, the overall configuration of the liquid crystal device manufactured by the manufacturing method of the present embodiment will be described. 1 is a plan view of a liquid crystal device manufactured by the manufacturing method of the present embodiment, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 focuses on one pixel. It is typical sectional drawing of the liquid crystal device of FIG.

  As shown in FIGS. 1 and 2, the liquid crystal device 100 uses, for example, a TFT substrate 10 using a quartz substrate, a glass substrate, or the like, and a glass substrate, a quartz substrate, or the like disposed opposite to the TFT substrate 10. A liquid crystal 50 is interposed between the counter substrate 20 and the counter substrate 20. The TFT substrate 10 and the counter substrate 20 that are arranged to face each other are bonded together by a sealing material 52.

  A display area 10 h of the TFT substrate 10 that constitutes the display area 40 of the liquid crystal device 100 is formed in an area in contact with the liquid crystal 50 of the TFT substrate 10. In addition, pixel electrodes 9a that constitute pixels and apply a driving voltage to the liquid crystal 50 together with a counter electrode 21 described later are arranged in a matrix in the display region 10h on the surface 10f side.

  Further, a counter electrode 21 for applying a driving voltage to the liquid crystal 50 together with the pixel electrode 9a is provided in a region in contact with the liquid crystal 50 on the surface 20f side of the counter substrate 20, and the counter electrode 21 is provided in a region facing the display region 10h. The display area 20h of the counter substrate 20 constituting the display area 40 of the liquid crystal device 100 is configured.

  An alignment film (hereinafter referred to as an inorganic alignment film) 16 made of an inorganic alignment film is provided on the pixel electrode 9 a of the TFT substrate 10, and a counter electrode formed over the entire surface of the counter substrate 20. An inorganic alignment film 26 is also provided on the electrode 21. A detailed configuration of each of the inorganic alignment films 16 and 26 will be described later.

  Further, in the display area 10h of the TFT substrate 10, a plurality of scanning lines (not shown) and a plurality of data lines (not shown) are wired so as to cross each other, and a pixel electrode is formed in an area partitioned by the scanning lines and the data lines. 9a are arranged in a matrix. A thin film transistor (TFT) (not shown) is provided corresponding to each intersection of the scanning line and the data line, and the pixel electrode 9a is electrically connected to each TFT.

  The TFT is turned on by the ON signal of the scanning line, whereby the image signal supplied to the data line is supplied to the pixel electrode 9a. A voltage between the pixel electrode 9 a and the counter electrode 21 provided on the counter substrate 20 is applied to the liquid crystal 50.

  A light shielding film 53 is provided on the counter substrate 20 as a frame that defines the display area 40 of the liquid crystal device 100.

  When the liquid crystal 50 is injected between the TFT substrate 10 and the counter substrate 20 by a known liquid crystal injection method, the sealing material 52 is missing and applied at a part of one side of the sealing material 52.

  The missing part of the sealing material 52 is a liquid crystal that is a notch for injecting the liquid crystal 50 into the region surrounded by the sealing material 52 between the TFT substrate 10 and the counter substrate 20 bonded from the missing part. An inlet 108 is formed. The liquid crystal injection port 108 is sealed with a sealant 109 after liquid crystal injection.

  In order to connect the data line driving circuit 101 which is a driver for supplying an image signal to a data line (not shown) of the TFT substrate 10 at a predetermined timing and driving the data line in an area outside the sealing material 52 and an external circuit. The external connection terminal 102 is provided along one side where the liquid crystal injection port 108 of the TFT substrate 10 is located. The external connection terminal 102 may be provided on the counter substrate 20.

  Connected to the external connection terminal 102 is one end of a flexible printed circuit board (hereinafter referred to as FPC) having a specific length (not shown) that electrically connects the liquid crystal device 100 to an electronic device such as a projector. Is done. By connecting the other end of the FPC to an electronic device such as a projector, the liquid crystal device 100 and the electronic device are electrically connected.

  By supplying scanning signals to scanning lines and gate electrodes (not shown) of the TFT substrate 10 along two sides adjacent to one side of the TFT substrate 10 provided with the external connection terminals 102, the gate electrode The scanning line driving circuits 103 and 104 which are drivers for driving are provided. The scanning line driving circuits 103 and 104 are formed on the TFT substrate 10 at a position facing the light shielding film 53 inside the sealing material 52.

  Further, on the TFT substrate 10, wiring lines 105 that connect the data line driving circuit 101, the scanning line driving circuits 103 and 104, the external connection terminal 102, and the vertical conduction terminal 107 are provided to face the three sides of the light shielding film 53. ing.

  The vertical conduction terminals 107 are formed on the four TFT substrates 10 at the corners of the sealing material 52. Between the TFT substrate 10 and the counter substrate 20, a vertical conductive material 106 having a lower end in contact with the vertical conductive terminal 107 and an upper end in contact with the counter electrode 21 is provided. And the counter substrate 20 are electrically connected.

  Further, as shown in FIG. 3, on the surface of the substrate constituting the TFT substrate 10 such as quartz substrate, glass, silicon substrate, etc. before forming various thin films, in addition to the TFT 30 and the pixel electrode 9a, a semiconductor thin film including these, A configuration of an insulating thin film or a conductive thin film is provided in a laminated structure. The laminated structure and the function of each laminated layer are well known and will be described briefly.

  In this stacked structure, the first layer including the scanning line 11a, the second layer including the TFT 30 and the like, the third layer including the storage capacitor 70, the fourth layer including the data line 6a and the like, the shield layer 400 and the like are sequentially arranged from the bottom. The fifth layer includes the sixth layer including the pixel electrode 9a, the inorganic alignment film 16, and the like. Further, interlayer insulating films described later are provided between the respective layers to prevent a short circuit between the above-described elements.

  In the first layer, for example, the scanning line 11a electrically connected to the TFT 30 made of tungsten silicide is formed. The scanning line 11a also has a light blocking function for blocking light that is about to enter the TFT 30 from below. A base insulating film 12 made of a silicon nitride film, a silicon oxide film, or the like is formed on the scanning line 11a by, for example, normal pressure or low pressure CVD. The base insulating film 12 insulates the scanning line 11 a from the TFT 30.

  The TFT 30 including the gate electrode 3a is provided in the second layer. The TFT 30 has, for example, an LDD (Lightly Doped Drain) structure. For example, the semiconductor layer 1 made of a crystallized silicon film such as a polysilicon film, the gate electrode 3a, and the gate electrode 3a covering the semiconductor layer 1 A main part is composed of a gate insulating film 2 that insulates the semiconductor layer 1.

  The semiconductor layer 1 includes a channel region 1a in which a channel is formed by an electric field from the gate electrode 3a, a low concentration source region 1b in the source region, a low concentration drain region 1c in the drain region, and a high concentration source region 1d in the source region. And a high concentration drain region 1e in the drain region.

  A relay electrode 719 is formed on the second layer as the same film as the gate electrode 3a. Grooves (contact holes) 12cv having the same width as the channel length of the semiconductor layer 1 extending along the data line 6a are dug in the base insulating film 12 on both sides of the semiconductor layer 1 in plan view. Due to the contact hole 12cv, the scanning line 11a and the gate electrode 3a in the same row have the same potential.

  A storage capacitor 70 is provided in the third layer. In the storage capacitor 70, a lower electrode 71 electrically connected to the high-concentration drain region 1e of the TFT 30 and the pixel electrode 9a and a capacitor electrode 300 are disposed to face each other via a dielectric film 75 serving as a capacitor. Is formed.

  A first interlayer insulating film 41 made of, for example, a silicon nitride film or a silicon oxide film is formed on the TFT 30 to the gate electrode 3 a and the relay electrode 719 and below the storage capacitor 70. The first interlayer insulating film 41 insulates at least the gate electrode 3 a and the lower electrode 71.

  A contact hole 81 interposed in the first interlayer insulating film 41 to electrically connect the high concentration source region 1d of the TFT 30 and the data line 6a is opened through the second interlayer insulating film 42. Yes.

  In addition, a contact hole 83 is formed in the first interlayer insulating film 41 so as to electrically connect the high concentration drain region 1e of the TFT 30 and the lower electrode 71 constituting the storage capacitor 70.

  Further, a contact hole 881 is formed in the first interlayer insulating film 41 so as to be electrically connected between the lower electrode 71 and the relay electrode 719. In addition, a contact hole 882 interposed to electrically connect the relay electrode 719 and the second relay layer 61 to the first interlayer insulating film 41 is opened while penetrating the second interlayer insulating film 42. Has been.

  A data line 6a is provided in the fourth layer. The data line 6a is formed as a film having a three-layer structure of an aluminum layer 41A, a titanium nitride layer 41TN, and a silicon nitride film layer 401 in order from the lower layer.

  In addition, a shield layer relay layer 60 and a second relay layer 61 are formed on the fourth layer as the same film as the data line 6a. In addition, a contact hole 801 is formed in the second interlayer insulating film 42 so as to be electrically connected between the shield layer relay layer 60 and the capacitor electrode 300.

  A shield layer 400 is formed on the fifth layer. Further, a third relay electrode 402 as a relay layer is formed on the fifth layer as the same film as the shield layer 400.

  A contact hole 803 interposed between the third interlayer insulating film 43 and the third relay electrode 402 and the second relay layer 61 is electrically connected to electrically connect the shield layer 400 and the shield layer relay layer 60 to each other. Contact holes 804 that are interposed to connect to each other are opened.

  As described above, the pixel electrodes 9a are formed in a matrix on the sixth layer. In addition, on the pixel electrode 9a and the fourth interlayer insulating film 44, a plurality of islands having a striped shape (hereinafter referred to as a stripe shape) in plan view and a rectangular shape as shown in FIG. An oxide film 150 composed of a portion is formed.

The oxide film 150 is made of an insulator such as silicon oxide such as SiO ₂ or SiO. The oxide film 150 is preferably made of the same material as the inorganic alignment film 16.

Further, the pixel electrode 9a and the fourth interlayer insulating film 44 are made of an insulator such as silicon oxide such as SiO ₂ or SiO so as to cover the plurality of oxide films 150 in a plan view. The inorganic alignment film 16 is formed by high-density plasma CVD to a thickness of, for example, 0.02 to 0.08 μm.

  The inorganic alignment film 16 is composed of a plurality of concavo-convex portions having a stripe shape in a plan view and having a triangular cross-section due to the shape of the plurality of oxide films 150. The inclined surfaces 16k1 and 16k2 constituting the side surfaces are inclined at an angle of, for example, θ1 = 45 ° with respect to the pixel electrode 9a and the fourth interlayer insulating film 44, respectively. That is, each concavo-convex part is composed of a triangle having a symmetrical cross-sectional shape.

  Note that the angle θ1 of the inclined surfaces 16k1 and 16k2 with respect to the pixel electrode 9a and the fourth interlayer insulating film 44 adjusts the bias power of a known lower electrode of a high-density plasma CVD apparatus (not shown) or a known IS-RF power. It is possible to adjust to an arbitrary angle by adjusting. Further, the angle θ1 of the inclined surfaces 16k1 and 16k2 with respect to the pixel electrode 9a and the fourth interlayer insulating film 44 is preferably 30 ° to 60 °, and more preferably 40 ° to 50 °.

  Furthermore, the width W between the concavo-convex parts is preferably 10 to 40 nm, and more preferably 10 to 20 nm.

  A fourth interlayer insulating film 44 is formed under the pixel electrode 9a. In addition, a contact hole 89 is formed in the fourth interlayer insulating film 44 so as to be electrically connected between the pixel electrode 9 a and the third relay electrode 402.

  In addition, as described above, the counter electrode 21 is formed over the entire surface of the counter substrate 20 on the surface of the substrate constituting the counter substrate 20 such as a quartz substrate, glass, or silicon substrate before forming various thin films. On the counter electrode 21, an oxide film 151 having the same configuration and shape as the above-described plurality of oxide films 150 and including a plurality of island portions having a rectangular cross-sectional shape as shown in FIG. Is formed.

Furthermore, on the counter electrode 21, an inorganic alignment film 26 made of an insulator such as silicon oxide such as SiO ₂ or SiO so as to cover the plurality of oxide films 151 in a plan view is, for example, 0 It is formed by high-density plasma CVD to a film thickness of 0.02 to 0.08 μm.

  In addition, since the shape, structure, and function of the inorganic alignment film 26 are the same as the shape, structure, and function of the inorganic alignment film 16 described above, description thereof is omitted. The inclined surfaces 16k1 and 16k2 of the inorganic alignment film 16 become the inclined surfaces 26k1 and 26k2 in the inorganic alignment film 26.

  The configuration of the liquid crystal device described above is not limited to the form as in the above embodiment, and various other forms can be considered.

  Next, a method for manufacturing the liquid crystal device 100 configured as described above, specifically, a method for forming the inorganic alignment films 16 and 26 will be described with reference to FIGS. 3, 4, and 5 described above. 4 is a partial cross-sectional view of the TFT substrate showing a state in which an oxide film is formed on the pixel electrode of the TFT substrate. FIG. 5 is an inorganic diagram so as to cover the oxide film on the pixel electrode of the TFT substrate in a plan view. It is a fragmentary sectional view of a TFT substrate showing a state where an alignment film is formed.

  In the alignment film forming method described below, the method for forming the inorganic alignment film 16 is the same as the method for forming the inorganic alignment film 26. Therefore, only the method for forming the inorganic alignment film 16 will be described as an example. Further, since other methods for manufacturing the liquid crystal device 100 are well known, the description thereof is omitted.

First, as shown in FIG. 3 described above, in the TFT substrate 10 formed up to the pixel electrode 9a, an oxide film 150 made of, for example, SiO ₂ is set on the entire pixel electrode 9a and the fourth interlayer insulating film 44. An oxide film forming step for forming the thickness is performed. Note that the material constituting the oxide film 150 is not limited to SiO ₂ as described above.

  Thereafter, a photoresist is formed at a predetermined position on the oxide film 150, and subsequently, various processes are performed on the oxide film 150 in the order of etching and photoresist stripping, whereby the pixel electrode 9a and the fourth interlayer insulating film 44 ( (Not shown in FIG. 4) The oxide film 150 is formed on a plurality of islands having a stripe shape in plan view and a rectangular cross section as shown in FIG. Perform the process. The etching in the oxide film etching process may be dry etching or wet etching.

Next, as shown in FIG. 5, for example, SiO ₂ so as to cover the plurality of oxide films 150 in a plan view on the pixel electrode 9 a and the fourth interlayer insulating film 44 (not shown in FIG. 5). An inorganic alignment film forming step is performed in which the inorganic alignment film 16 configured as described above is formed to a thickness of, for example, 0.02 to 0.08 μm by high-density plasma CVD. Specifically, the inorganic alignment film 16 is formed using, for example, argon sputtering using a high-density plasma CVD apparatus.

Note that the material constituting the inorganic alignment film 16 is preferably the same as that of the oxide film 150. Therefore, as described above, it is not limited to SiO ₂ .

  After the inorganic alignment film formation step, the inorganic alignment film 16 has a plurality of irregularities having a stripe shape in a plan view and a triangular cross section due to the shape of the plurality of island-shaped oxide films 150. Formed in the part.

  In addition, the inclined surfaces 16k1 and 16k2 constituting the side surfaces of the uneven portions are formed so as to be inclined at an angle of, for example, θ1 = 45 ° with respect to the pixel electrode 9a and the fourth interlayer insulating film 44. That is, each concavo-convex part is formed in a triangle having a symmetrical cross-sectional shape.

  In addition, the formation method of the inorganic alignment film 16 demonstrated above is the method in which the inorganic alignment film 26 is formed on the counter electrode 21 of the counter substrate 20, and the plurality of oxide films 150 become the plurality of oxide films 151. Since they are the same, the description thereof is omitted.

  Thus, in the present embodiment, when the inorganic alignment film 16 is formed on the pixel electrode 9a and the fourth interlayer insulating film 44 of the TFT substrate 10, on the pixel electrode 9a and the fourth interlayer insulating film 44, After forming the oxide film 150 composed of a plurality of island portions having a stripe shape in a plan view and a rectangular cross-sectional shape, a plurality of oxide films are formed on the pixel electrode 9a and the fourth interlayer insulating film 44. It was shown that the inorganic alignment film 16 is formed using high-density plasma CVD so as to cover the film 150 in a plan view.

  According to this, the inorganic alignment film 16 is formed on the pixel electrode 9a due to the shape of the plurality of rectangular oxide films 150 in the same manner as when formed by θ1 = 45 ° by conventional oblique deposition. Formed.

  As a result, the inorganic alignment film 16 having the plurality of inclined surfaces 16k1 and 16k2 of θ1 = 45 ° can define an appropriate alignment direction and pretilt angle with respect to the liquid crystal 50 in the vertical alignment mode.

  As described above, the inorganic alignment film 16 is specially formed by using high-density plasma CVD used for forming various semiconductor thin films, insulating thin films, or conductive thin films as described above, while being excellent in mass productivity and reliability. Without using a separate device, the inorganic alignment film 16 can be efficiently formed on the pixel electrode 9a of the TFT substrate 10 at lower cost, higher mass productivity, and higher reliability than before.

  The above effects are the same even when the inorganic alignment film 26 is formed on the counter electrode 21 of the counter substrate 20.

  Hereinafter, modifications will be described. In the present embodiment, the case where the inorganic alignment films 16 and 26 are formed on the TFT substrate 10 and the counter substrate 20 has been described as an example. On the substrate 20, the inorganic alignment film may be formed by the above-described method, and the organic alignment film may be formed on the substrate on which the inorganic alignment film is not formed, and the rubbing process may be performed as in the related art. Even if it does in this way, the effect similar to this Embodiment can be acquired with respect to the board | substrate with which the inorganic alignment film was formed.

(Second Embodiment)
6 is a partial cross-sectional view of the TFT substrate showing a state in which a photoresist is formed on the pixel electrode of the TFT substrate of FIG. 4 so as to cover a part of the oxide film formed on the pixel electrode in a plan view. FIG. 7 is a partial cross-sectional view of the TFT substrate showing a state where wet etching is performed on the oxide film of FIG.

  8 is a partial cross-sectional view of the TFT substrate showing a state where the photoresist is removed from FIG. 7, and FIG. 9 is an inorganic alignment film so as to cover the oxide film on the pixel electrode of the TFT substrate in a plan view. It is a fragmentary sectional view of the TFT substrate which shows the state which formed.

  The manufacturing method of the liquid crystal device of the second embodiment is different from the manufacturing method of the liquid crystal device of the first embodiment described above on the side surface on each side of the oxide film patterned into a plurality of islands. The only difference is that the tapered surface is formed. Therefore, only this difference will be described, and the same components as those of the liquid crystal device of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  Also in this embodiment, since the method for forming the inorganic alignment film 16 and the method for forming the inorganic alignment film 26 are the same in the method for forming the alignment film, only the method for forming the inorganic alignment film 16 is used. Will be described as an example.

  First, the above-described oxide film forming step is performed, and then, the shape of the oxide film 150 in plan view on the pixel electrode 9a and the fourth interlayer insulating film 44 (not shown in FIG. 4) is a stripe shape. As shown in FIG. 4, after performing the above-described oxide film etching process for forming a plurality of islands having a rectangular cross-sectional shape, as shown in FIG. 6, the pixel electrode 9a and the fourth interlayer insulating film 44 ( A photoresist 160 is formed so as to cover the other half of the island-shaped oxide film 150 in a plan view (not shown in FIG. 7).

  Next, wet etching is performed on each oxide film 150 using a chemical solution such as BHF (buffered hydrofluoric acid), HF (hydrofluoric acid), and the like, as shown in FIG. A taper surface forming step of forming a taper surface 150t having a curved cross-sectional shape on each side surface is performed. Thereafter, as shown in FIG. 8, the photoresist 160 is removed.

Finally, an inorganic orientation made of, for example, SiO ₂ so as to cover the plurality of oxide films 150 in a plan view on the pixel electrode 9a and the fourth interlayer insulating film 44 (not shown in FIG. 9). An inorganic alignment film forming step is performed in which the film 116 is formed to a thickness of, for example, 0.02 to 0.08 μm by high density plasma CVD. Specifically, the inorganic alignment film 116 is formed using, for example, argon sputtering using a high-density plasma CVD apparatus.

  After the inorganic alignment film formation step, the inorganic alignment film 116 has a stripe shape in a plan view due to the shape of the plurality of island-shaped oxide films 150 each having a tapered surface 150t on one side surface, The cross-sectional shape is formed in a plurality of uneven portions having an asymmetric triangular shape.

  In addition, the inclined surface 116k1 constituting one side surface of each uneven portion is, for example, at an angle of θ2 = 30 ° to 60 ° with respect to the pixel electrode 9a and the fourth interlayer insulating film 44 due to the tapered surface 150t. The inclined surface 116k2 that is formed to be inclined and forms the other side surface is formed to be inclined at an angle of, for example, θ3 = 60 ° to 30 ° with respect to the pixel electrode 9a and the fourth interlayer insulating film 44.

  Furthermore, also in this Embodiment, it is preferable that the width W between each uneven | corrugated | grooved part is 10-40 nm, and it is more preferable that it is 10-20 nm.

  The method for forming the inorganic alignment film 116 described above is the same as the method for forming the inorganic alignment film on the counter electrode 21 of the counter substrate 20 and the plurality of oxide films 150 to be the plurality of oxide films 151. Since it is the same, the description is abbreviate | omitted.

  As described above, in this embodiment, each island-shaped oxide 150 having the tapered surface 150t formed on each side surface thereof by wet etching on the pixel electrode 9a and the fourth interlayer insulating film 44 in plan view. It was shown that the inorganic alignment film 116 is formed by using high-density plasma CVD so as to cover in the above state.

  According to this, the inorganic alignment film 116 is formed on the pixel electrode 9a of the TFT substrate 10 by the conventional oblique deposition due to the shape of the plurality of oxide films 150 each having the tapered surface 150t. Similarly, the inclined surface 116k1 is formed at an angle θ2 with respect to the pixel electrode 9a and the fourth interlayer insulating film 44 of the tapered surface 150t, and the inclined surface 116k2 is formed at an angle θ3 with respect to the pixel electrode 9a and the fourth interlayer insulating film 44 of the tapered surface 150t. Is formed.

  That is, since the cross-sectional shape of each concavo-convex portion of the inorganic alignment film 116 can be formed in an asymmetrical triangular shape, the inorganic alignment film 116 has, for example, an angle θ2 of the inclined surface 116k1 of 30 ° to 40 ° and an inclined surface 116k2. By forming the angle θ3 of 60 ° to 50 °, the inorganic alignment film 116 becomes substantially the same as the shape of the organic alignment film after the rubbing treatment with a constant strength, and has an equivalent function. . Therefore, the inorganic alignment film 116 can define the alignment direction and the pretilt angle of the liquid crystal 50 in the horizontal alignment mode.

  The angle θ2 and the angle θ3 can be formed at optimum angles according to the type of liquid crystal 50 used for horizontal alignment.

  As described above, the inorganic alignment film 116 is specially formed by using high-density plasma CVD used for forming various semiconductor thin films, insulating thin films or conductive thin films as described above, while being excellent in mass productivity and reliability. Without using a separate device, the inorganic alignment film 116 can be efficiently formed on the pixel electrode 9a of the TFT substrate 10 at lower cost, higher mass productivity, and higher reliability than before.

  The above effects are the same even when an inorganic alignment film is formed on the counter electrode 21 of the counter substrate 20.

  Hereinafter, modifications will be described. 10, a photoresist is formed on the pixel electrode of the TFT substrate of FIG. 4 so as to cover a part of the oxide film formed on the pixel electrode in a plan view as compared with the case shown in FIG. 6. FIG. 11 is a partial cross-sectional view of the TFT substrate showing a state where dry etching is performed on the oxide film of FIG. 10.

In the present embodiment, it has been shown that the etching of each side surface of each oxide film 150 is performed by wet etching, and each oxide film 150 is formed with a tapered surface 150t having a curved surface. Etching is performed using an etching gas such as C ₄ H ₈ (octafluorocyclobutane), CF ₄ (carbon tetrafluoride) SF ₆ (sulfur hexafluoride), CHF ₃ (trifluoromethane), or XeF ₂ (xenon difluoride). The dry etching used may be used.

  Specifically, first, the above-described oxide film forming step is performed, and then the shape of the oxide film 150 in plan view is striped on the pixel electrode 9a and the fourth interlayer insulating film 44 (not shown in FIG. 4). As shown in FIG. 4, after the oxide film etching process is performed to form a plurality of island portions having a rectangular cross-sectional shape as shown in FIG. 4, the pixel electrode 9a and the fourth interlayer insulation are formed as shown in FIG. Photoresist 160 is formed on film 44 (not shown in FIG. 10) so as to cover the other side surface of each island-like oxide film 150 in a plan view more than the position shown in FIG. .

  Next, by performing dry etching on each oxide film 150, as shown in FIG. 7, a tapered surface is formed so that a tapered surface 150t having an inclined surface is formed on one side surface of each oxide film 150, respectively. Perform the process.

After that, as described above, the photoresist 160 was removed, and finally, the plurality of oxide films 150 were viewed in plan on the pixel electrode 9a and the fourth interlayer insulating film 44 (not shown in FIG. 9). An inorganic alignment film forming step is performed in which an inorganic alignment film 116 made of, for example, SiO ₂ is formed by high-density plasma CVD so as to be covered with the state.

  Even if formed in this way, the inorganic alignment film 116 is formed in substantially the same shape as when wet etching is used when the tapered surface 150 t is formed on the oxide film 150. That is, even when dry etching is used when forming the tapered surface 150t on the oxide film 150, the same effect as in this embodiment can be obtained. This is the same even when an inorganic alignment film is formed on the counter electrode 21 of the counter substrate 20.

  Hereinafter, another modification will be described. In the present embodiment, the case where the inorganic alignment film is formed on the TFT substrate 10 and the counter substrate 20 is shown as an example. However, the present invention is not limited to this, and the TFT substrate 10 is not limited to this. The inorganic alignment film may be formed only on or on the counter substrate 20 by the above-described method, and the organic alignment film may be formed on the substrate on which the inorganic alignment film is not formed, and the rubbing process may be performed as in the past. Even if it does in this way, the effect similar to this Embodiment can be acquired with respect to the board | substrate with which the inorganic alignment film was formed.

  Further, the liquid crystal device is not limited to the above-described illustrated examples, and it is needless to say that various changes can be made without departing from the gist of the present invention. For example, the above-described liquid crystal device has been described by taking an active matrix type liquid crystal display module using an active element (active element) such as a TFT (thin film transistor) as an example. However, the present invention is not limited to this, and a TFD (thin film diode) or the like. An active matrix type liquid crystal display module using active elements (active elements) may be used.

The top view of the liquid crystal device manufactured by the manufacturing method of this Embodiment. Sectional drawing cut | disconnected along the II-II line | wire in FIG. FIG. 2 is a schematic cross-sectional view of the liquid crystal device in FIG. 1 focusing on one pixel. The fragmentary sectional view of a TFT substrate which shows the state which formed the oxide film on the pixel electrode of a TFT substrate. The fragmentary sectional view of a TFT substrate which shows the state which formed the inorganic alignment film on the pixel electrode of a TFT substrate so that an oxide film might be covered in planar view. FIG. 5 is a partial cross-sectional view of the TFT substrate showing a state in which a photoresist is formed on the pixel electrode of the TFT substrate of FIG. 4 so as to cover a part of the oxide film formed on the pixel electrode in a plan view. FIG. 7 is a partial cross-sectional view of a TFT substrate showing a state where wet etching is performed on the oxide film of FIG. 6. FIG. 8 is a partial cross-sectional view of the TFT substrate showing a state where the photoresist is removed from FIG. 7. The fragmentary sectional view of a TFT substrate which shows the state which formed the inorganic alignment film on the pixel electrode of a TFT substrate so that an oxide film might be covered in planar view. TFT showing a state in which a photoresist is formed on the pixel electrode of the TFT substrate of FIG. 4 so as to cover a part of the oxide film formed on the pixel electrode in a plan view as compared with the case shown in FIG. The fragmentary sectional view of a board | substrate. FIG. 11 is a partial cross-sectional view of a TFT substrate showing a state where dry etching is performed on the oxide film of FIG. 10.

Explanation of symbols

  9 ... Pixel electrode, 10 ... TFT substrate, 20 ... Counter substrate, 21 ... Counter electrode, 50 ... Liquid crystal, 100 ... Liquid crystal device, 150 ... Oxide film, 150t ... Tapered surface, 151 ... Oxide film, 161 ... Inorganic alignment film.

Claims (4)

A method of manufacturing a liquid crystal device, wherein an alignment film for aligning liquid crystals interposed between the first substrate and the second substrate is formed on a first substrate and a second substrate that are arranged to face each other. ,
An oxide film forming step of forming an oxide film on an electrode for applying a driving voltage to the liquid crystal of at least one of the first substrate and the second substrate;
An oxide film etching step for forming the oxide film by etching on a plurality of island portions having a stripe shape in a plan view and a rectangular cross-sectional shape;
An inorganic alignment film forming step of forming an inorganic alignment film among the alignment films by using high-density plasma CVD so as to cover the electrode in a state in plan view on the electrode;
A method for manufacturing a liquid crystal device, comprising:   After the oxide film etching process, prior to the inorganic alignment film forming process, a taper surface is formed on each side surface of the oxide film formed on the plurality of islands having a rectangular cross-sectional shape. The method for manufacturing a liquid crystal device according to claim 1, further comprising a surface forming step.   The method of manufacturing a liquid crystal device according to claim 2, wherein the tapered surface forming step is performed by wet etching.   The method for manufacturing a liquid crystal device according to claim 2, wherein the tapered surface forming step is performed by dry etching.

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