JP3973891B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an active liquid crystal display device using a switching element such as a thin film transistor (TFT) and a manufacturing method thereof, and more particularly to a light shielding means for shielding a switching element and a manufacturing method thereof.
[0002]
[Prior art]
  2. Description of the Related Art In recent years, liquid crystal display devices have attracted attention and are actively researched and developed as displays having advantages such as light weight, thinness, and low power consumption. The structure of the liquid crystal display device is such that “pixels” formed by sandwiching liquid crystal molecules between transparent electrodes are arranged in a matrix. The principle of operation is that by applying an arbitrary voltage between the transparent electrodes of individual pixels and changing the alignment state of the liquid crystal molecules, the degree of polarization of the light passing through the liquid crystal is changed, thereby changing the light transmittance. Is to control.
[0003]
  Liquid crystal display devices are classified into a simple matrix type and an active matrix type based on the operation principle. In particular, an active matrix liquid crystal display device includes an active element such as a thin film transistor (TFT) as a switching element for each pixel, and can send a signal to each pixel independently, so that the resolution is excellent and clear. Attention has been paid to the fact that images can be obtained.
[0004]
  Currently, TFTs using amorphous silicon thin films are frequently used as switching elements in active matrix liquid crystal display devices. Recently, a TFT using a polysilicon thin film formed by laser crystallization by heat-treating an amorphous silicon thin film at a temperature of about 600 ° C. or higher by irradiation with an excimer laser or the like has been proposed. . Since the polysilicon thin film has higher mobility than the amorphous silicon thin film, in addition to the pixel switching element, the drive circuit portion for driving the pixel switching element is the same as the TFT using the polysilicon thin film. There is an advantage that it can be formed on a substrate.
[0005]
  By the way, as described above, the liquid crystal display device is a device that controls the transmittance of light by changing the degree of polarization of light passing through the liquid crystal, and does not include a light emitting portion itself. Therefore, it is necessary to prepare some light source. For example, in the case of a reflective liquid crystal display device, display is performed by reflecting incident light from the outside with a reflective electrode. On the other hand, in the case of a transmissive liquid crystal display device, an illuminating device such as a backlight is disposed behind the device, and display is performed by light incident from the illuminating device. Alternatively, in a projector or the like, a metal halide lamp or the like is used as a light source, and projection is performed by combining a lens system and a liquid crystal display device.
[0006]
  In general, when light is irradiated onto a semiconductor such as silicon and light absorption occurs, a so-called photoelectric effect occurs in which electrons are excited in a conduction band and holes are excited in a valence band to generate electron-hole pairs. The same applies to the amorphous silicon thin film or the polysilicon thin film used for the active layer such as the switching element of the pixel described above, and electron-hole pairs are generated in the thin film when irradiated with light. Therefore, in a TFT using an amorphous silicon thin film or a polysilicon thin film as an active layer, when light is irradiated, a photocurrent caused by an electron-hole pair is generated, which increases a leakage current when the TFT is turned off. This causes problems such as deterioration of the contrast of the liquid crystal display.
[0007]
  In the case of a reflective liquid crystal display device, since a reflective electrode mainly made of a metal film or the like connected to the TFT is disposed so as to cover the TFT, incident light from the outside does not reach the TFT directly. Therefore, problems such as an increase in TFT leakage current are unlikely to occur. However, in the case of a transmissive liquid crystal display device, the TFT is not only exposed to direct light from the backlight, but indirect incident light from directions other than the backlight may reach the TFT. In the case of a projector or the like, light that has once passed through the liquid crystal display device may return to the TFT due to reflection by a lens system or the like. Various ideas have been proposed so that these incident lights do not reach the TFT.
[0008]
  For example,(1)In Japanese Patent Application Laid-Open No. 58-159516, as shown in FIG. 10, a light shielding film (upper light shielding layer) 102 and a light shielding film (lower light shielding layer) 103 with an insulating layer sandwiched between an upper portion and a lower portion of a transistor (active layer) 101. Discloses a liquid crystal display panel (liquid crystal display device).(1)According to this technique, incident light from above and below the active layer 101 is blocked, so that the light leakage current of the TFT can be suppressed and display characteristics can be improved.
[0009]
  Also,(2)In JP-A-10-293320, as shown in FIG. 11, a bonded SOI (Silicon) in which an upper light shielding layer 112 and a light shielding layer (lower light shielding layer) 113 are arranged above and below a MOSFET (active layer) 111, respectively. A liquid crystal panel (liquid crystal display device) using an on-insulator substrate is disclosed.(2)According to this technique, light incident directly from the upper part and the lower part on the active layer 111 can be shielded, so that it is possible to prevent the light leakage current of the TFT.
[0010]
  Also,(3)In Japanese Patent Laid-Open No. 2001-66587, as shown in FIG. 12, a liquid crystal display device is disclosed in which one layer is disposed below a polysilicon (active layer) 121 that is a switching element, and two light shielding layers are disposed above. ing. Specifically, a black matrix (upper light shielding layer) 122 and a lower light shielding film (lower light shielding layer) 123 are disposed above and below the active layer 121. Further, a data line for inputting a data signal to the active layer 121, the width of the data line (source wiring layer) 124 disposed between the active layer 121 and the upper light shielding layer 122 is set to be lower light shielding. By making it substantially equal to the width of the layer 123, the light leakage current is suppressed.
[0011]
  (3)According to this technique, the source wiring layer 124 disposed below the upper light shielding layer 122 is used as a light shielding layer above the active layer 121, so that the transmitted light is projected onto a screen or the like. It is said that the light leakage current can be suppressed while taking the necessary pixel aperture ratio as large as possible. Further, by making the width of the source wiring layer 124 and the width of the lower light shielding layer 123 substantially equal, reflected light (indirect light) from an optical system such as a lens can be reflected on the upper light shielding layer 122, the lower light shielding layer 123, and the source wiring. Since multiple reflections between the layers 124 and incidence on the active layer 121 can be prevented, the light leakage current can be further suppressed.
[0012]
[Problems to be solved by the invention]
  However, the conventional technique cannot prevent a light leakage current generated when indirect light from an optical system such as a lens enters the active layer of the TFT, or the pixel aperture ratio decreases. The problem arises.
[0013]
  For example, the above(1)and(2)In this technique, since one light shielding layer is provided above and below the active layer, most of the incident light is considered not to reach the active layer. However, the light incident on the liquid crystal display device is not only direct light from a light source such as a backlight or a metal halide lamp, but also indirectly light that reaches the active layer indirectly due to the shape of the liquid crystal display device. is there. Therefore,(1)and(2)In this technique, the pixel aperture ratio decreases when an attempt is made to prevent the light leakage current of the TFT generated by the indirect light. Details will be described below.
[0014]
  (1)and(2)A liquid crystal display device 137 and a liquid crystal display device 138 applied to this technique are shown in FIGS. The liquid crystal display devices 137 and 138 have a transparent substrate 134, and an active layer 131, an upper light shielding layer 132, a lower light shielding layer 133, an insulating layer 135, and an insulating layer 136 are disposed on the transparent substrate 134. Specifically, an upper light shielding layer 132 and a lower light shielding layer 133 are disposed above and below the active layer 131 with insulating layers 135 and 136 interposed therebetween. The liquid crystal display devices 137 and 138 are different in the area (width) of the upper light shielding layer 132 relative to the active layer 131, and the area of the upper light shielding layer 132 in the liquid crystal display device 137 is set smaller than that of the liquid crystal display device 138. Yes. Note that arrows (A), (B), and (C) indicate directions of light incident on the liquid crystal display devices 137 and 138.
[0015]
  In the liquid crystal display devices 137 and 138, the direct light incident from above and below as indicated by arrows (A) and (B) is blocked by the upper light shielding layer 132 and the lower light shielding layer 133, so that the light does not reach the active layer 131. However, the liquid crystal display device 137 cannot shield light incident from an oblique direction as indicated by an arrow (c), and the light reaches the active layer 131 to generate a light leakage current. In order to avoid this, light can be shielded by increasing the area of the upper light shielding layer 132 as in the liquid crystal display device 138. However, since the area of the light shielding portion is increased, the pixel aperture ratio is reduced. That is, the above(1)and(2)In any of these techniques, it is conceivable that the pixel aperture ratio decreases because the light shielding layer becomes large if light incident from an oblique direction is shielded.
[0016]
  On the other hand, the above(3)In this technique, as described above with reference to FIG. 12, the source wiring layer 124 disposed below the upper light shielding layer 122 is used as a light shielding layer above the active layer 121, so that the pixel aperture ratio is maximized. It is said that it is possible. In addition, the above(3)In this technique, since the width of the source wiring layer 124 and the width of the lower light-shielding layer 123 are made substantially equal, indirect light can be prevented from entering and light leakage current can be suppressed.
[0017]
  However, since the source wiring layer 124 and the active layer 121 need a certain distance for the following reasons, a part of light incident from an oblique direction reaches the active layer 121, and light leakage occurs. Electric current is generated.
[0018]
  That is, a gate disposed so that the potential of the source wiring layer 124 does not affect the electrical characteristics of the active layer 121 or between the source wiring layer 124 and the active layer 121 so as to be orthogonal to the source wiring layer 124. For reasons such as reducing the parasitic capacitance between the wiring layer (not shown) and the source wiring layer 124, a certain distance is required between the source wiring layer 124 and the active layer 121 or the gate wiring layer. Therefore, a part of light incident from an oblique direction reaches the active layer 121 due to multiple reflection between the source wiring layer 124 and the lower light shielding layer 123.
[0019]
  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a liquid crystal display device and a method for manufacturing the same capable of reliably suppressing light leakage current without reducing the pixel aperture ratio. It is in.
[0020]
[Means for Solving the Problems]
  In the liquid crystal display device (first device) according to the present invention, a metal wiring layer including a source wiring layer for inputting a data signal to an active layer and a gate wiring layer intersect in order to solve the above problem. In a liquid crystal display device having an active layer at a position corresponding to the region to be turned on, a lower light-shielding layer is disposed below the active layer, and an upper light-shielding layer disposed between the metal wiring layer and the gate wiring layer is disposed above the active layer. At least a layer.
[0021]
  The first device is a liquid crystal display device provided with an active layer such as a TFT at a position corresponding to a portion where the metal wiring layer and the gate wiring layer intersect. That is, the position of the active layer provided in the first device is not limited to the position where the metal wiring layer and the gate wiring layer intersect. Specifically, the position of the active layer is included in the technical scope of the present invention as long as it is in a corresponding relationship with the part even if the position is separated from the part where the two wiring layers intersect. .
[0022]
  The first device further includes at least a lower light shielding layer below the active layer, and an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer above the active layer. Thereby, for the reason described below, the light leakage current can be surely suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto the screen or the like.
[0023]
  Conventionally, the source wiring layer (metal wiring layer) disposed above the gate wiring layer itself is substituted for the light shielding layer, or the light shielding layer is formed above the gate wiring layer and the source wiring layer. Therefore, it is difficult to form the upper light shielding layer disposed on the active layer in the vicinity of the active layer. Therefore, in order to prevent light from an oblique direction from entering the active layer, it is necessary to increase the area of the upper light shielding layer.
[0024]
  On the other hand, in the first device, the upper light shielding layer is disposed between the metal wiring layer and the gate wiring layer. Therefore, when the active layer is disposed between the metal wiring layer and the gate wiring layer, the upper light shielding layer and the upper light shielding layer are separated from the gate wiring layer or the metal wiring layer disposed higher than the active layer and the distance between the active layer and the active wiring layer. The distance from the active layer can be set small. In addition, when the metal wiring layer and the gate wiring layer are arranged above the active layer, the upper light shielding is caused by the distance between the metal wiring layer and the active layer arranged above the metal wiring layer and the gate wiring layer. The distance between the layer and the active layer can be set small.
[0025]
  That is, in the first device, the upper light shielding layer is disposed closer to the active layer. Therefore, light incident from an oblique direction can be more reliably shielded than before. Further, for example, even when the area of the light shielding layer is the same as the conventional one, light incident from an oblique direction can be more reliably shielded than the conventional one.
[0026]
  In other words, in the first device, light from the same direction can be shielded with an area smaller than the area of the upper light shielding layer required in the conventional configuration. Therefore, it is possible to prevent a decrease in pixel aperture ratio. Further, since the upper light shielding layer can be provided electrically independently from the gate wiring layer and the metal wiring layer, it is possible to reduce adverse effects on the electrical characteristics of the active layer.
[0027]
  When the non-light-shielding region where the upper light-shielding layer cannot be formed to form a contact hole for electrically connecting the metal wiring layer or the gate wiring layer and the active layer is formed due to the structure of the liquid crystal display device In this case, the non-light-shielding region may be shielded by the metal wiring layer or the gate wiring layer.
[0028]
  In other words, in this case, the upper light-shielding layer may be disposed locally with respect to the active layer portion that cannot be shielded by the gate wiring layer and the metal wiring layer. In this way, the area of the metal wiring layer or gate wiring layer above the upper light shielding layer need not be as large as possible.
[0029]
  Also,Reference exampleIn order to solve the above problem, the liquid crystal display device (second device) includes a metal wiring layer including a source wiring layer for inputting a data signal to the active layer, and a lower layer than the metal wiring layer. In a liquid crystal display device having an active layer disposed below the gate wiring layer at a position corresponding to a portion where the gate wiring layer intersects, a lower light-shielding layer is provided below the active layer, and the active layer At least an upper light shielding layer disposed below the metal wiring layer is provided on the upper part.This is a configuration.
[0030]
  The second device includes an active layer disposed below the gate wiring layer at a position corresponding to a portion where the metal wiring layer and the gate wiring layer disposed below the metal wiring layer intersect. A liquid crystal display device. That is, the position of the active layer provided in the second device is not limited to the position where the metal wiring layer and the gate wiring layer intersect. Specifically, even if the position of the active layer is spaced from the part where the two wiring layers intersect, the position of the active layer is a position corresponding to the part.Good.
[0031]
  In addition, the second device includes at least a lower light shielding layer below the active layer and an upper light shielding layer disposed below the metal wiring layer including the source wiring layer above the active layer. Thereby, for the reason described below, the light leakage current can be surely suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto the screen or the like.
[0032]
  Conventionally, the source wiring layer (metal wiring layer) disposed above the gate wiring layer itself is substituted for the light shielding layer, or the light shielding layer is formed above the gate wiring layer and the source wiring layer. Therefore, it is difficult to form the upper light shielding layer disposed on the active layer in the vicinity of the active layer. Therefore, in order to prevent light from an oblique direction from entering the active layer, it is necessary to increase the area of the upper light shielding layer.
[0033]
  On the other hand, in the second device, the upper light shielding layer is disposed between the metal wiring layer and the gate wiring layer. Therefore, the distance between the upper light shielding layer and the active layer can be set smaller than the distance between the metal wiring layer and the active layer disposed above the gate wiring layer.
[0034]
  That is, in the second device, the upper light shielding layer is disposed closer to the active layer. Therefore, light incident from an oblique direction can be more reliably shielded than before. Further, for example, even when the area of the light shielding layer is the same as the conventional one, light incident from an oblique direction can be more reliably shielded than the conventional one.
[0035]
  In other words, in the second device, light from the same direction can be shielded with an area smaller than the area of the upper light shielding layer required in the conventional configuration. Therefore, it is possible to prevent a decrease in pixel aperture ratio. Further, since the upper light shielding layer can be provided electrically independently from the gate wiring layer and the metal wiring layer, it is possible to reduce adverse effects on the electrical characteristics of the active layer.
[0036]
  When the non-light-shielding region where the upper light-shielding layer cannot be formed to form a contact hole for electrically connecting the metal wiring layer or the gate wiring layer and the active layer is formed due to the structure of the liquid crystal display device In this case, the non-light-shielding region may be shielded by the metal wiring layer or the gate wiring layer.
[0037]
  In other words, in this case, the upper light-shielding layer may be disposed locally with respect to the active layer portion that cannot be shielded by the gate wiring layer and the metal wiring layer. In this way, the area of the metal wiring layer or gate wiring layer above the upper light shielding layer need not be as large as possible.
[0038]
  In order to solve the above problems, the liquid crystal display device according to the present invention further includes a third light-shielding layer disposed above the upper light-shielding layer above the active layer. Yes.
[0039]
  According to the above configuration, the active layer is provided with one light-shielding layer at the bottom and two light-shielding layers at the top. Therefore, the light is incident directly on the active layer forming region or incident from an oblique direction. Light can be further reduced. Thereby, the light leakage current can be more reliably suppressed.
[0040]
  In the liquid crystal display device according to the present invention, in order to solve the above problems, the upper light shielding layer is further formed along a step of a gate wiring layer or a metal wiring layer disposed below the upper light shielding layer. It is characterized by that.
[0041]
  According to the above configuration, even if either the gate wiring layer or the metal wiring layer is disposed below the upper light shielding layer, the gate wiring layer or the metal wiring layer is compared with the case where the upper light shielding layer is formed in a flat plate shape. A part of the light shielding layer can be made closer to the active layer by forming along the step. As a result, light incident from an oblique direction can be more reliably shielded, and light leakage current can be more reliably suppressed.
[0042]
  In order to solve the above problems, the liquid crystal display device according to the present invention is characterized in that at least one of the third light shielding layer and the lower light shielding layer is used in combination as a metal wiring layer or a gate wiring layer. It is said.
[0043]
  According to the above configuration, since at least one of the third light shielding layer and the lower light shielding layer is used as a metal wiring layer or a gate wiring layer, the light incident on the active layer is shielded with a simpler configuration. can do.
[0044]
  In order to solve the above problem, the liquid crystal display device according to the present invention further includes a channel region, a source side high concentration impurity region and a drain side high concentration impurity region sandwiching the channel region, and a channel The LDD structure is characterized in that low concentration impurity regions are formed between the region and the source side high concentration impurity region and between the channel region and the drain side high concentration impurity region, respectively.
[0045]
  According to the above configuration, the active layer includes the channel region, the source side high concentration impurity region and the drain side high concentration impurity region sandwiching the channel region, and between the channel region and the source side high concentration impurity region, and Since it has an LDD structure (Lightly doped drain) structure in which a low concentration impurity region is formed between the channel region and the drain side high concentration impurity region, the electric field strength generated in the active layer can be weakened. As a result, the light leakage current can be further suppressed.
[0046]
  In the liquid crystal display device according to the present invention, in order to solve the above-described problem, the upper light shielding layer is further formed so as to cover at least the junction portion of each of the above-described regions constituting the active layer and the low-concentration impurity region. It is characterized by being.
[0047]
  According to the above configuration, in the case where the active layer has an LDD structure, the range where the upper light shielding layer is formed includes at least the junction portion and the low-concentration impurity region of each region constituting the active layer. The electric field strength generated inside the active layer can be weakened more reliably. As a result, the light leakage current can be more reliably suppressed.
[0048]
  Further, in order to solve the above problems, the liquid crystal display device according to the present invention, except that each of the light shielding layers is used as a metal wiring layer or a gate wiring layer,(1)A single layer of Ta, Ti, W, Mo, Cr, Ni, polysilicon, or(2)MoSi₂, TaSi2, WSi₂CoSi₂, NiSi₂, PtSi, Pd₂S, HfN, ZrN, TiN, TAN, NbN, TiC, TaC, TiB₂Any single layer, or(3)the above(2)It is characterized by a multi-layer structure combining any one of the above.
[0049]
  In addition, in the method of manufacturing a liquid crystal display device according to the present invention, a metal wiring layer including a source wiring layer for inputting a data signal to an active layer intersects with a gate wiring layer in order to solve the above problem. In a method for manufacturing a liquid crystal display device having an active layer at a position corresponding to a part, an upper light shielding layer disposed on an active layer between a step of forming a metal wiring layer and a step of forming a gate wiring layer Including at least a step of formingMethod may be.
[0050]
  According to the above method, the upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is formed on the active layer. That is, the upper light shielding layer is formed closer to the upper part of the active layer than in the conventional case. Thereby, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like. The order of forming the metal wiring layer and the gate wiring layer is not particularly limited, and either layer may be formed first.
[0051]
  In addition, in order to solve the above problems, a method for manufacturing a liquid crystal display device according to the present invention includes a metal wiring layer including a source wiring layer for inputting a data signal to an active layer, and a lower layer than the metal wiring layer. Forming a metal wiring layer and a gate wiring in a method of manufacturing a liquid crystal display device having an active layer disposed below the gate wiring layer at a position corresponding to a portion where the gate wiring layer disposed on the gate intersects Between the step of forming the layer, at least a step of forming an upper light-shielding layer disposed on the active layer may be included.
[0052]
  According to the above method, the upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is formed on the active layer. That is, the upper light shielding layer is formed closer to the upper part of the active layer than in the conventional case. Thereby, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like.
[0053]
  In addition, in order to solve the above problems, a method for manufacturing a liquid crystal display device according to the present invention includes a metal wiring layer including a source wiring layer for inputting a data signal to an active layer, and a lower layer than the metal wiring layer. Forming a lower light-shielding layer on a substrate in a method of manufacturing a liquid crystal display device including an active layer disposed below a gate wiring layer at a position corresponding to a portion intersecting with a gate wiring layer disposed on the substrate Forming an active layer on the substrate on which the lower light shielding layer is formed via the first insulating layer; and forming a gate wiring layer on the first insulating layer and the active layer via the second insulating layer. Forming an upper light shielding layer on the second insulating layer and the gate wiring layer via the third insulating layer; and forming a fourth insulating layer on the third insulating layer and the upper light shielding layer. Forming and on the fourth insulating layer Comprising at least a step of forming a metal wiring layer.
[0054]
  According to the above method, the lower light shielding layer is formed below the active layer via the first insulating layer. Further, an upper light shielding layer is formed on the active layer between the gate wiring layer via the third insulating layer and the metal wiring layer via the fourth insulating layer. As a result, the distance between the upper light-shielding layer and the active layer can be set smaller than the distance between the metal wiring layer and the active layer, so that the pixel aperture ratio required for projecting transmitted light onto a screen or the like is reduced. Therefore, the light leakage current can be reliably suppressed.
[0055]
  In order to solve the above-described problem, the method of manufacturing a liquid crystal display device according to the present invention further includes the step of forming the upper light shielding layer on the second insulating layer and the gate wiring layer via the third insulating layer. Depositing an insulating layer to be a third insulating layer on the second insulating layer and the gate wiring layer and forming the third insulating layer by an etching process; and an upper light shielding layer on the third insulating layer; And a step of forming an upper light shielding layer by an etching process.
[0056]
  According to the above method, since the corner portion of the convex portion of the third insulating layer formed by having the gate wiring layer in the lower portion has a smooth curve, the upper light shielding layer is etched when the upper light shielding layer is etched. It is possible to reliably perform an etching process in a range that does not require forming a layer. Thereby, the fall of a pixel aperture ratio can be prevented more reliably.
[0057]
  Further, in the method of manufacturing the liquid crystal display device according to the present invention, in order to solve the above-described problem, the step of forming the upper light shielding layer on the second insulating layer and the gate wiring layer via the third insulating layer includes Forming a sidewall-shaped insulating layer having a curved convex shape in the outer direction of the gate wiring layer on both sides of the gate wiring layer facing the wiring direction of the metal wiring layer; and a second insulating layer Forming a third insulating layer on the gate wiring layer and the sidewall-shaped insulating layer, depositing a light shielding layer on the third insulating layer as an upper light shielding layer, and etching the upper light shielding layer Forming at least a step of forming.
[0058]
  According to the above method, since the corner portion of the convex portion of the third insulating layer formed by having the gate wiring layer in the lower portion has a smooth curve, the upper light shielding layer is etched when the upper light shielding layer is etched. It is possible to reliably perform an etching process in a range that does not require forming a layer. Thereby, the fall of a pixel aperture ratio can be prevented more reliably.
[0059]
  In order to solve the above problems, the method for manufacturing a liquid crystal display device according to the present invention further forms a third light-shielding layer on the fourth insulating layer and the metal wiring layer via the fifth insulating layer. It may include steps.
[0060]
  According to the above method, since one light shielding layer is formed below the active layer and two light shielding layers are formed above the active layer, it is possible to more reliably shield light incident from an oblique direction. Thereby, the light leakage current can be more reliably suppressed.
[0061]
  The position of the active layer formed in the above manufacturing method is not limited to the position where the metal wiring layer and the gate wiring layer intersect. Specifically, the position of the active layer is included in the technical scope of the present invention as long as it is in a corresponding relationship with the part even if the position is separated from the part where the two wiring layers intersect. .
[0062]
DETAILED DESCRIPTION OF THE INVENTION
  [Reference example1]
  One of the present inventionReference example1 will be described with reference to FIGS. 1 to 6, 9, and 15. FIG.
One of the present inventionReference exampleFIG. 1 shows a cross-sectional structure of a main part of the liquid crystal display device 42 according to FIG. 1, and FIG. 2 shows a cross-sectional structure taken along the line A-A ′ in FIG. The liquid crystal display device 42 is an active matrix liquid crystal display device in which switching elements including active layers 35 are arranged in a matrix on a transparent substrate 40 made of, for example, glass or quartz. The active layer 35 is a semiconductor and is not particularly limited, and examples thereof include amorphous, polycrystalline, and single crystal semiconductors made of Si (silicon), Ge, GaAs, GaP, CdS, CdSe, and the like. Of the examples, polycrystalline silicon is more preferable.
[0063]
  A specific configuration is that a metal wiring layer 33 made of a metal material such as Al including a source wiring layer 33 a for inputting a data signal to the active layer 35, and a gate wiring arranged below the metal wiring layer 33. An active layer 35 disposed below the gate wiring layer 32 is provided at a position corresponding to a portion where the layer 32 intersects. That is, the liquid crystal display device 42 is a planar type liquid crystal display device.
[0064]
  In order to maintain insulation from the active layer 35 between the active layer 35 and each of the wiring layers 32 and 33, SiO 2₂The insulating layer 38 is formed except for the contact hole portion 16 which is a connection portion with the active layer 35. Although the metal wiring layer 33 of the liquid crystal display device 42 includes the drain wiring layer 33b, the present invention is not limited to this. Further, the positional relationship between the metal wiring layer 33 and the gate wiring layer 32 does not limit the present invention. For example, the metal wiring layer 33 may be arranged below the gate wiring layer 32.
[0065]
  Further, in order to prevent the light leakage current of the active layer 35, a lower light shielding layer 41 is disposed below the active layer 35, and an upper light shielding layer disposed between the gate wiring layer 32 and the metal wiring layer 33 above the active layer 35. 34 is formed through an insulating layer 38. Thereby, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like.
[0066]
  That is, the conventional configuration in which the source wiring layer 33a itself is substituted as the light shielding layer, or the light shielding layer is formed above the source wiring layer 33a including the transparent electrode (not shown) facing the substrate 40. Compared with the upper light shielding layer 34, the upper light shielding layer 34 is disposed closer to the active layer 35. Accordingly, it is possible to reliably shield not only direct light incident from the vertical direction as indicated by arrows (A) and (B) shown in FIG. 2 but also light incident from an oblique direction as indicated by arrow (C).
[0067]
  Further, for example, even when the area of the light shielding layer is the same as the conventional one, light incident from an oblique direction can be more reliably shielded than the conventional one. In other words, light from the direction of the arrow (c) can be shielded with an area smaller than the area of the upper light shielding layer required in the conventional configuration. Therefore, according to the configuration of the liquid crystal display device 42, it is possible to prevent the pixel aperture ratio from being lowered.
[0068]
  Further, due to the structure of the liquid crystal display device, a non-light-shielding region where the upper light-shielding layer 34 cannot be formed to form a contact hole for electrically connecting the metal wiring layer 33 or the gate wiring layer 32 and the active layer is active. In the case where it occurs in a part of the layer 35, the light incident on the active layer 35 may be blocked by the metal wiring layer 33 or the gate wiring layer 32.
[0069]
  For example, in the case of the liquid crystal display device 42, the upper light shielding layer 34 is not formed at both ends of the active layer 35 by the contact hole portion 16 connecting the metal wiring layer 33 and the active layer 35, but the metal wiring layer The configuration may be such that light can be shielded by 33. Although not shown, the upper part of the active layer 35 in which the upper light shielding layer 34 is not formed by the contact hole 16 connecting the gate wiring layer 32 and the active layer 35 can be shielded by the gate wiring layer 32. What is necessary is just composition.
[0070]
  That is, the upper light-shielding layer 34 is a light-shielding layer that is locally provided for the portion of the active layer 35 that cannot be shielded by the gate wiring layer 32 and the metal wiring layer 33, and is higher than the upper light-shielding layer 34. This is a light shielding layer formed between the gate wiring layer 32 and the metal wiring layer 33 in order to minimize the area of the metal wiring layer 33.
[0071]
  The upper light shielding layer 34 is locally disposed at the position where each active layer 35 is formed, and is electrically independent of the gate wiring layer 32 and the metal wiring layer 33. Therefore, it is possible to reduce the adverse effect of the upper light shielding layer 34 on the electrical characteristics of the active layer 35.
[0072]
  However, when the upper light-shielding layer 34 is locally disposed (electrically isolated) as described above, depending on the layout (layout) and thickness of each of the layers, the upper light-shielding layer 34 is active for the following reasons. There is also a possibility that the electrical properties of the layer 35 may be adversely affected.
[0073]
  That is, the insulating layer 38 may act like an insulator inside a capacitor having a certain capacitance. Here, the metal wiring layer 33 and the gate wiring layer 32 or the active layer 35 act like the electrodes of the capacitor.
[0074]
  On the other hand, in the above capacitor, if the upper light shielding layer 34 is an electrically conductive layer, the upper light shielding layer 34 acts like a single conductor provided in an insulator inside the capacitor. This is because the locally disposed upper light shielding layer 34 is electrically insulated (floating).
[0075]
  In other words, the capacitance of the insulating layer 38 between the metal wiring layer 33 and the upper light shielding layer 34 and the capacitance of the insulating layer 38 between the upper light shielding layer 34 and the gate wiring layer 32 or the active layer 35 are the upper part. Coupling (capacitive coupling) is performed via the light shielding layer 34.
[0076]
  Thereby, depending on the thickness of the insulating layer 38 disposed above and below the upper light shielding layer 34, the insulation between the metal wiring layer 33, the gate wiring layer 32, and the active layer 35 may cause the upper light shielding layer 34 to be insulated. May be incomplete for.
[0077]
  As a result, the potentials of the gate wiring layer 32 and the active layer 35 may change through the upper light shielding layer 34, which is a conductor layer, in accordance with the change in the potential of the metal wiring layer 33. That is, the upper light shielding layer 34 may adversely affect the electrical characteristics of the active layer 35.
[0078]
  Therefore, it is preferable that the upper light shielding layer 34 is extended along one end side of the liquid crystal display device 42 along the gate wiring layer 32 to apply a voltage. Thereby, since the potential of the upper light shielding layer 34 can be arbitrarily set, the influence of the potential of the gate wiring layer 32 or the metal wiring layer 33 on the electrical characteristics of the active layer 35 can be adjusted.
[0079]
  That is, the potential of the upper light shielding layer 34 can be prevented from changing according to the potentials of the metal wiring layer 33 and the gate wiring layer 32. As a result, it is possible to further reduce the adverse effect of the upper light shielding layer 34 on the electrical characteristics of the active layer 35, and to stabilize the electrical characteristics of the active layer 35.
[0080]
  In the case where the upper light shielding layer 34 is extended along the gate wiring layer 32, the width of the upper light shielding layer 34 in the portion without the active layer 35, that is, the portion that does not need to be shielded from light is seen from the sectional view of FIG. The width of the gate wiring layer 32 is made equal. Accordingly, it is possible to prevent the pixel aperture ratio from being lowered by extending the upper light shielding layer 34.
[0081]
  On the other hand, on the active layer 35, as shown in FIGS. 1 and 2, a third light shielding layer 36 disposed above the metal wiring layer 33 is formed. Thereby, since one light shielding layer is disposed below the active layer 35 and two light shielding layers are disposed above the active layer 35, the light leakage current can be more reliably suppressed. The same effect can be obtained even if the third light shielding layer 36 is disposed at the same position as the metal wiring layer 33.
[0082]
  The active layer 35 includes at least an impurity region into which an impurity such as P or As is implanted in a region other than a region (a channel region 35c (see FIG. 5C)) located below the gate wiring layer 32. The single drain structure is preferable. As a result, the electric field strength generated in the active layer 35 can be weakened, so that the light leakage current can be further suppressed.
[0083]
  The active layer 35 has an N-type high-concentration impurity region such as P or As containing a relatively high-concentration impurity in a region located at a connection portion with the metal wiring layer 33, and the high-concentration impurity. An LDD (Lightly doped drain) structure having an N-type low-concentration impurity region such as P or As containing a relatively low-concentration impurity between the region and the channel region 35c is more preferable. As a result, the electric field strength generated in the active layer 35 can be further weakened, so that the light leakage current can be further suppressed.
[0084]
  That is, the active layer 35 of the liquid crystal display device 42 has a source region (source side high concentration impurity region) 35d and a drain region made of high concentration impurities in a region located at a connection portion between the source wiring layer 33a and the drain wiring layer 33b. (Drain-side high-concentration impurity regions) 35e, and LDD structures having low-concentration impurity regions 35a and 35b (see FIG. 5C) between the source region 35d and drain region 35e and the channel region 35c, respectively. It is more preferable that
[0085]
  The upper light shielding layer 34 is not particularly limited, but is preferably formed along a step of the gate wiring layer 32 disposed below the upper light shielding layer 34. That is, in the liquid crystal display device 42, the upper light shielding layer 34 is formed in an L shape along the step of the gate wiring layer 32. As a result, the distance between the upper light shielding layer 34 and the active layer 35 in the portion where the gate wiring layer 32 is not present does not increase compared to the case where the upper light shielding layer 34 is formed in a straight line (flat plate shape). It is possible to more reliably shield light incident from an oblique direction. That is, in the portion where the gate wiring layer 32 is not present, the upper light shielding layer 34 is disposed closer to the active layer 35, so that light incident from an oblique direction can be more reliably shielded.
[0086]
  In addition, the metal wiring layer 33 disposed above the upper light shielding layer 34 may be configured to be used as the third light shielding layer 36. As a result, it is possible to provide a light shielding layer having a simpler structure with one layer below the active layer and two layers above the active layer.
[0087]
  In addition, the material of each light shielding layer is not particularly limited as long as it has a light shielding effect, except when used in combination as a metal wiring layer or a gate wiring layer,(1)A single layer of Ta, Ti, W, Mo, Cr, Ni, polysilicon, or(2)MoSi₂, TaSi2, WSi₂CoSi₂, NiSi₂, PtSi, Pd₂S, HfN, ZrN, TiN, TAN, NbN, TiC, TaC, TiB₂Any single layer, or(3)the above(2)A multilayer structure in which any of the single layers is combined is preferable.
[0088]
  Next, a method for manufacturing the liquid crystal display device 42 will be described.
The method for manufacturing the liquid crystal display device 42 includes at least the step of forming the upper light shielding layer 34 disposed on the active layer 35 between the step of forming the metal wiring layer 33 and the step of forming the gate wiring layer 32. It is the method of including. Thus, an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is formed on the active layer.
[0089]
  That is, the upper light shielding layer is formed closer to the upper part of the active layer than in the conventional case. As a result, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio required for projecting the transmitted light onto a screen or the like. Although the detailed manufacturing method of the liquid crystal display device 42 is demonstrated below, this invention is not limited to this.
[0090]
  As shown in FIG. 3A, a light shielding layer to be the lower light shielding layer 41 is deposited on the substrate 40 by a CVD method or a sputtering method, and the lower light shielding layer 41 is formed by photo / etching. Next, as shown in FIG. 3B, a first insulating layer 43 is deposited on the substrate 40 and the lower light shielding layer 41.
[0091]
  Next, an active layer 35 is formed on the first insulating layer 43 as shown in FIG. Specifically, for example, when the active layer 35 is polycrystalline silicon, generally after depositing an amorphous silicon thin film on the first insulating layer 43 with a film thickness of about 50 to 200 nm by a CVD method or the like. Polycrystalline by heat treatment at high temperature or laser light irradiation. Thereafter, patterning is performed by a photo / etching process to form an active layer 35 having a predetermined shape. Thereafter, impurity ion implantation may be performed for threshold voltage control.
[0092]
  Next, as shown in FIG. 3D, a second insulating layer 44 is formed on the active layer 35. The second insulating layer 44 is formed by CVD deposition, oxidation, or both. Subsequently, the gate wiring layer 32 is formed on the second insulating layer 44. The gate wiring layer 32 is formed with an appropriate width above the active layer 35. However, it is preferable that the gate wiring layer 32 is formed approximately at the center of the active layer 35 corresponding to the position where the channel region 35c is formed.
[0093]
  Here, it is preferable that the active layer 35 has an LDD (Lightly doped drain) structure by a process described below.
First, 5 × 10 5 using the second insulating layer 44 as a mask.¹²~ 1x10¹⁴/ Cm²Low concentration impurities are implanted into the active layer 35 by ion implantation with a moderate dose. As a result, as shown in FIG. 4A, low-concentration impurity regions 35a and 35b (hereinafter abbreviated as low-concentration regions 35a and 35b) are formed in regions other than the region of the active layer 35 located below the gate wiring layer 32. Is formed). On the other hand, in the region of the active layer 35 located below the gate wiring layer 32, a channel region 35c that does not contain a low concentration impurity is formed.
[0094]
  Next, as shown in FIG. 4B, the periphery of the gate wiring layer 32 is conveniently patterned with a photoresist 10, and then 1 × 10.¹⁵~ 5x10¹⁵/ Cm²A high concentration impurity is implanted into the active layer 4 with a moderate dose, and a high concentration impurity region is formed outside the low concentration regions 35a and 35b. That is, the region where the source wiring layer 33a is formed in the upper part and the active layer 35 in the region where the drain wiring layer 33b is formed in the upper part are referred to as a source region 35d and a drain region 35e made of high-concentration impurities, respectively.
[0095]
  The LDD structure in which the active layer 35 is formed with the low concentration regions 35a, 35b between the channel region 35c and the source region 35d and the drain region 35e by the process described in FIGS. can do. As a result, since the electric field strength generated inside the active layer 35, for example, the electric field strength between the channel region 35c and the drain region 35e can be weakened, an effect of further suppressing the light leakage current can be obtained. Note that the step of forming the low-concentration regions 35a and 35b is not necessarily required, and the same effect can be obtained even with a single drain structure in which regions other than the channel region 35c are impurity regions.
[0096]
  Next, as shown in FIG. 4C, after the photoresist 10 is removed, a third insulating layer 45 is deposited by about 50 to 300 nm by a CVD method or the like. At this time, the thickness of the third insulating layer 45 is preferably as thin as possible, and the distance between the upper light-shielding layer 34 and the active layer 35 to be formed in a later process can be reduced, and it is efficient without increasing the area of the upper light-shielding layer 34. It is possible to shield light.
[0097]
  Next, a light shielding layer to be the upper light shielding layer 34 is deposited by CVD or sputtering, and the upper light shielding layer 34 is formed by, for example, photo / etching. Thus, the upper light shielding layer 34 is formed in an L shape along the convex portion 45a of the third insulating layer 45 formed by having the gate wiring layer 32 in the lower portion. As a result, compared with the case where the upper light shielding layer 34 is formed in a straight line, the distance between the upper light shielding layer 34 and the active layer 35 in the portion where the gate wiring layer 32 is not widened, so that the incident light is incident from an oblique direction. The light to be able to be shielded more reliably.
[0098]
  Here, the range in which the upper light shielding layer 34 is formed is a range in which light incident on the active layer 35 cannot be blocked by the gate wiring layer 32 and the metal wiring layer 33 due to the structure. For example, as shown in FIG. 9, the area that can be shielded by the gate wiring layer 32 does not form the upper light shielding layer 34, but the source side upper light shielding layer 34a on the source wiring layer 33a side and the drain side upper part on the drain wiring layer 33b side. The structure which forms the light shielding layer 34b may be sufficient.
[0099]
  In addition, the freedom degree which applies an electric potential independently to 34a and 34b is obtained by isolate | separating an upper light shielding layer from 34a and 34b. However, in order to suppress a decrease in the pixel aperture ratio, it is preferable to set the range of the upper light shielding layer 34 so as to make the area of the metal wiring layer 33 as small as possible.
[0100]
  Further, when the active layer 35 has a single drain structure, it is preferable that the range in which the upper light shielding layer 34 is formed includes the upper part of the junction in each region in the active layer 35. Further, when the active layer 35 has an LDD structure, it is preferable that the upper light shielding layer 34 is formed so as to include the upper portion of the junction portion and the upper portion of the low concentration impurity region in each region in the active layer 35. As a result, the light leakage current can be more reliably suppressed.
[0101]
  Specifically, (I) in the case of a single drain structure composed of a channel region 35c, a source region 35d, and a drain region 35e, a junction between the source region 35d and the channel region 35c, and the channel region 35c and the drain Range including each upper part of the junction with the region 35e; (II) In the case of the LDD structure in which the low concentration regions 35a and 35b are formed between the channel region 35c, the source region 35d, and the drain region 35e, the source region 35d And the low concentration region 35a, the low concentration region 35a, the low concentration region 35a and the channel region 35c, the channel region 35c and the low concentration region 35b, the low concentration region 35b, and the low concentration region An upper light-shielding layer 34 is formed in a range including each upper portion of the joint portion between 35b and the drain region 35e. Rukoto is preferable. In the case where the active layer 35 has an LDD structure, the details of the range in which the upper light shielding layer 34 is formed will be described later.
[0102]
  Next, as shown in FIG. 5A, an insulating layer is deposited on the third insulating layer 45 and the upper light-shielding layer 34 by, for example, about 600 nm to form a fourth insulating layer 46. The method for forming the fourth insulating layer 46 is not particularly limited, but the insulating layer is preferably formed of BPSG (Borophosphosilicate glass), and then heat-treated at a high temperature of about 850 to 950 ° C. or CMP ( The planarization may be performed by a chemical mechanical planarization process or the like. Next, an opening for forming a contact hole portion 16 for extracting an electrode is formed on the source region 35d and the drain region 35e, and a source wiring layer 33a and a drain wiring layer 33b are formed.
[0103]
  Next, a fifth insulating layer 47 is formed on the metal wiring layer 33 and the fourth insulating layer 46 and planarized. As shown in FIG. 5B, it is preferable to form a fifth insulating layer 47 on the nitride layer 19 after the nitride layer 19 is formed. Specifically, the nitride layer 19 is deposited on the metal wiring layer 33 and the fourth insulating layer 46 to form a passivation layer, and then hydrogenation is performed. Subsequently, after the fifth insulating layer 47 is deposited, the fifth insulating layer 47 is formed by performing planarization by etch back or CMP.
[0104]
  Next, as shown in FIG. 5C, a third light-shielding layer to be the third light-shielding layer 36 is deposited on the fifth insulating layer 47 by a CVD method or a sputtering method, and patterned to obtain the third A light shielding layer 36 is formed. FIG. 6 shows a B-B ′ cross section of FIG. Since the upper light shielding layer 34 blocks the light incident from the oblique direction (c), the light does not reach the active layer 35 (the low concentration region 35a in FIG. 6), so that the light leakage current can be suppressed.
[0105]
  With the above manufacturing method of the liquid crystal display device 42, the lower light shielding layer 41 is formed below the active layer 35 via the first insulating layer 43. Further, an upper light shielding layer 34 disposed between the gate wiring layer 32 and the metal wiring layer 33 is formed on the active layer 35. Specifically, the upper light shielding layer 34 is formed between the gate wiring layer 32 via the third insulating layer 45 and the metal wiring layer 33 via the fourth insulating layer 46. Thereby, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like.
[0106]
  Further, in the manufacturing method of the liquid crystal display device 42, the third light shielding layer 36 is formed on the fourth insulating layer 46 and the metal wiring layer 33 through the fifth insulating layer 47. As a result, a light shielding layer of one layer is formed below the active layer 35 and two light shielding layers are formed above the active layer 35, so that light incident from an oblique direction can be more reliably shielded. Thereby, the light leakage current can be more reliably suppressed.
[0107]
  Although not shown, an insulating layer is further formed on the third light shielding layer 36 and the fifth insulating layer 47, and a transparent electrode such as ITO and the drain wiring layer 33b are formed on the insulating layer. Is formed, and a transparent electrode is electrically connected to the drain wiring layer 33b.
[0108]
  Next, the range in which the upper light shielding layer 34 is formed in the case where the active layer 35 has the LDD structure (II) will be described.
When the active layer 35 has an LDD structure, the most light-shielded portions are the low concentration regions 35a and 35b as shown in FIG. 15A, and then the low concentration regions 35a and 35b and the channel region 35c. Junction portions 55 and 56, low-concentration region 35a and source region 35d (high-concentration region) junction portion 57, low-concentration region 35b and drain region 35e (high-concentration region) junction portion 58, and channel region 35c. It is. However, since the channel region 35c is shielded from light by the gate wiring layer (gate electrode) 32, the upper light shielding layer 34 does not need to be shielded from light.
[0109]
  Therefore, when the active layer 35 has an LDD structure, the upper light shielding layer 34 is formed in an area above the junction portions 55, 56, 57, and 58 in each region in the active layer 35, and the low concentration impurity region 35 a, It preferably includes the top of 35b.
[0110]
  Further, as shown in FIG. 15B, the active layer 35 has a structure in which the LDD structure of (II) is arranged in series, the range in which the upper light shielding layer 34 is formed is as shown in FIG. It is the same as the range described in the above. That is, the range in which the upper light shielding layer 34 is formed preferably includes the upper portions of the junction portions 59 to 62 in the respective regions in the active layer 35 and the upper portions of the low concentration impurity regions 35a and 35b.
[0111]
  Note that when the LDD structures are arranged in series, the high-concentration impurity region formed between the low-concentration region 35a and the low-concentration region 35b can be said to be the drain region 35e and the source region 35d. Specifically, in FIG. 15B, the high-concentration impurity region disposed in the center of the active layer 35 is a high-concentration impurity region disposed on the drain side for the gate wiring layer 32a, that is, the drain region 35e. is there. On the other hand, for the gate wiring layer 32b, it is a high concentration impurity region arranged on the source side, that is, the source region 35d.
[0112]
  Further, even when the active layer 35 (transistor) has a structure in which the LDD structure is arranged in series as shown in FIG. 15B, the portions to be shielded most are the low concentration regions 35a and 35b. Next, the junction portions 60 and 61 between the low concentration regions 35a and 35b and the channel region 35c, the junction portion 59 between the low concentration region 35a and the source region 35d, the junction portion 62 between the low concentration region 35b and the drain region 35e, And a channel region 35c. However, since the channel region 35c is shielded from light by the gate wiring layer (gate electrode) 32, the upper light shielding layer 34 does not need to be shielded from light.
[0113]
  Embodiment1]
  The embodiment of the present invention will be described with reference to FIG. For convenience of explanation,Reference exampleThe members having the same functions as those in FIG.
After removing the photoresist 10 through the steps described with reference to FIGS. 3A to 3D, 4A, and 4B, as shown in FIG. An insulating layer to be the insulating layer 45 is deposited by about 550 to 800 nm by the CVD method or the like. Next, an etching process for etching the entire surface of about 500 nm is performed to form a third insulating layer 45 of about 50 to 300 nm as shown in FIG. At this time, the thickness of the third insulating layer 45 is preferably as thin as possible, and the distance between the upper light shielding layer 34 and the active layer 35 to be formed in a later process can be reduced, and the area of the upper light shielding layer 34 can be increased efficiently. It is possible to shield light. Further, the corner portion of the convex portion 45a of the third insulating layer 45 formed by having the gate wiring layer 32 in the lower portion has a smooth curve.
[0114]
  Next, a light shielding layer to be the upper light shielding layer 34 is deposited by CVD or sputtering, and the upper light shielding layer 34 is formed by, for example, a photo / etching process. Here, the range in which the upper light shielding layer 34 is formed is as follows.Reference exampleSimilar to 1, the gate wiring layer 32 and the metal wiring layer 33 (see FIG. 5A) have a structure in which light cannot be shielded. However, in order to suppress a decrease in the pixel aperture ratio, the range of the upper light shielding layer 34 is set so as to make the area of the metal wiring layer 33 as small as possible. Further, when the upper light shielding layer 34 is formed, the upper light shielding layer 34 may be formed by etching the corner portion along the curve.
[0115]
  By the process described with reference to FIGS. 7A and 7B, the corner portion of the convex portion 45a becomes a smooth curve. Thus, when the upper light shielding layer 34 is etched, the etching process is reliably performed on the convex portions 45a that do not require the upper light shielding layer 34, that is, the convex portions 45a that are not located on the active layer 35. be able to. In other words, it is possible to prevent the light shielding layer from remaining in the convex portion 45a that does not require the upper light shielding layer 34 to be formed. As a result, it is possible to more reliably prevent the pixel aperture ratio from being lowered.
Thereafter, the steps described in FIGS. 5A to 5C are performed.
[0116]
  By the above manufacturing method, the upper light shielding layer 34 is formed along the convex portion 45a. Therefore, the upper light shielding layer 34 is not shielded in the portion where the gate wiring layer 32 is not provided, as compared with the case where the upper light shielding layer 34 is formed linearly. Since the distance between the layer 34 and the active layer 35 does not increase, light incident from an oblique direction can be more reliably shielded. Further, since the lower light shielding layer 41 is formed below the active layer 35 and the upper light shielding layer 34 disposed below the metal wiring layer 33 (see FIG. 5A) is formed above, the pixel aperture ratio is formed. The light leakage current can be surely suppressed without lowering.
[0117]
  Embodiment2]
  The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation,Reference exampleThe members having the same functions as those in FIG.
After removing the photoresist 10 through the steps described in FIG. 3A to FIG. 3D, FIG. 4A and FIG. 4B, as shown in FIG. Side wall-shaped insulating layers 51 having curved convex shapes in the outer direction of the gate wiring layer are formed on both side surfaces of the gate wiring layer 32 facing the direction. Specifically, the insulating layer 51 is an insulating layer for causing a curve to wait on both side surfaces of the gate wiring layer 32, and is an insulating layer having a convex shape toward the outside of the gate wiring layer 32.
[0118]
  Next, the third insulating layer 45 is deposited by about 50 to 300 nm by a CVD method or the like. At this time, the thickness of the third insulating layer 45 is preferably as thin as possible, and the distance between the upper light-shielding layer 34 and the active layer 35 to be formed in a later process can be reduced, and it is efficient without increasing the area of the upper light-shielding layer 34. It is possible to shield light. Through the above steps, as shown in FIG. 8, the corner portion of the convex portion 45a of the third insulating layer 45 formed by having the gate wiring layer 32 in the lower portion becomes a smooth curve.
[0119]
  Next, a light shielding layer to be the upper light shielding layer 34 is deposited by CVD or sputtering, and the upper light shielding layer 34 is formed by photo / etching. Here, the range in which the upper light shielding layer 34 is formed is a range where the gate wiring layer 32 and the metal wiring layer 33 (see FIG. 5A) cannot be shielded in light of the structure, as in the first embodiment. However, in order to suppress a decrease in the pixel aperture ratio, the range of the upper light shielding layer 34 is set so as to make the area of the metal wiring layer 33 as small as possible. Further, when the upper light shielding layer 34 is formed, the upper light shielding layer 34 may be formed by etching the corner portion along the curve.
[0120]
  By the process described based on FIG. 8, the corner portion of the convex portion 45a becomes a smooth curve. Thus, when the upper light shielding layer 34 is etched, the etching process is reliably performed on the convex portions 45a that do not require the upper light shielding layer 34, that is, the convex portions 45a that are not located on the active layer 35. be able to. In other words, it is possible to prevent the light shielding layer from remaining in the convex portion 45a that does not require the upper light shielding layer 34 to be formed. As a result, it is possible to more reliably prevent the pixel aperture ratio from being lowered.
Thereafter, the steps described in FIGS. 5A to 5C are performed.
[0121]
  By the above manufacturing method, the upper light shielding layer 34 is formed along the convex portion 45a. Therefore, the upper light shielding layer 34 is not shielded in the portion where the gate wiring layer 32 is not provided, as compared with the case where the upper light shielding layer 34 is formed linearly. Since the distance between the layer 34 and the active layer 35 does not increase, light incident from an oblique direction can be reliably shielded. Further, since the lower light shielding layer 41 is formed below the active layer 35 and the upper light shielding layer 34 disposed below the metal wiring layer 33 (see FIG. 5A) is formed above, the pixel aperture ratio is formed. The light leakage current can be surely suppressed without lowering.
[0122]
  [Reference example 2]
  Of the present inventionReference exampleWill be described. BookReference exampleIs a top gate type liquid crystal display device having an active layer above a metal wiring layer including a source wiring layer and a drain wiring layer, and a gate wiring layer disposed above the active layer.AhThe
[0123]
  Specifically, in the top gate type liquid crystal display device, a lower light shielding layer is provided below the active layer, and an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is provided above the active layer. At least, the configuration may be provided.
[0124]
  As a result, the upper light shielding layer is disposed closer to the active layer than in the prior art, and light incident from an oblique direction can be reliably shielded. That is, the light leakage current can be reliably suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like.
[0125]
  Also, due to the structure of the liquid crystal display device, a non-light-shielding region where the upper light-shielding layer cannot be formed to form a contact hole for electrically connecting the metal wiring layer or the gate wiring layer and the active layer is formed In this case, the non-light-shielding region may be shielded by the metal wiring layer or the gate wiring layer. In other words, in this case, the upper light-shielding layer may be disposed locally with respect to the active layer portion that cannot be shielded by the gate wiring layer and the metal wiring layer. In this way, the area of the metal wiring layer or gate wiring layer above the upper light shielding layer need not be as large as possible.
[0126]
  That is, the upper light-shielding layer is a light-shielding layer provided locally with respect to the active layer portion that cannot be shielded by the gate wiring layer and the metal wiring layer, and the area of the metal wiring layer above the upper light-shielding layer. Is a light shielding layer formed between the gate wiring layer and the metal wiring layer.
[0127]
  The upper light shielding layer is locally disposed at the position where each active layer is formed, and is electrically independent of the gate wiring layer and the metal wiring layer. Therefore, it is possible to reduce the adverse effect of the upper light shielding layer on the electrical characteristics of the active layer.
[0128]
  However, when the upper light-shielding layer 34 is locally disposed (electrically isolated) as described above, the metal wiring layer 33 and the gate depend on the layout (layout) and thickness of each layer. Insulation between the wiring layer 32 and the active layer 35 may be incomplete, which may adversely affect the electrical characteristics of the active layer 35.
[0129]
  Therefore, it is preferable to apply a voltage by extending the upper light shielding layer to one end side of the liquid crystal display device along the gate wiring layer or the metal wiring layer. Thereby, since the potential of the upper light shielding layer can be arbitrarily set, the influence of the potential of the gate wiring layer or the metal wiring layer on the electrical characteristics of the active layer can be adjusted. That is, the potential of the upper light shielding layer can be prevented from changing according to the potentials of the metal wiring layer and the gate wiring layer. As a result, the adverse effect of the upper light shielding layer on the electrical characteristics of the active layer can be further reduced, and the electrical characteristics of the active layer can be stabilized.
[0130]
  When the upper light shielding layer is extended along the gate wiring layer or the metal wiring layer, the width of the upper light shielding layer in the portion without the active layer, that is, the portion that does not need to be shielded, is the gate wiring layer or the metal wiring layer. Equal to the width of. Accordingly, it is possible to prevent the pixel aperture ratio from being lowered by extending the upper light shielding layer.
[0131]
  Further, it is preferable that a third light shielding layer disposed above the upper light shielding layer is provided on the active layer. As a result, since the lower layer of the active layer has one light shielding layer and the upper layer has two light shielding layers, the light directly incident on the active layer forming region or the light incident from an oblique direction is further reduced. Can be made. Thereby, the light leakage current can be more reliably suppressed.
[0132]
  The active layer preferably has a single drain structure in which an impurity region into which an impurity such as P or As is implanted is included in a region other than a region (channel region) located below the gate wiring layer. As a result, the electric field strength generated inside the active layer can be weakened, so that the light leakage current can be further suppressed.
[0133]
  The active layer has an N-type high concentration impurity region such as P or As containing a relatively high concentration impurity in a region located at the connection portion with the metal wiring layer, and the high concentration impurity region An LDD (Lightly doped drain) structure having an N-type low concentration impurity region such as P or As containing a relatively low concentration impurity between the channel region is more preferable. As a result, the electric field strength generated in the active layer can be further reduced, so that the light leakage current can be further suppressed.
[0134]
  In the case where the active layer has the LDD structure, it is preferable that the upper light shielding layer is formed so as to cover at least the junction portion of each of the regions constituting the active layer and the low concentration impurity region. Thereby, the range in which the upper light-shielding layer is formed includes at least the junction portion of each of the above-described regions constituting the active layer and the low-concentration impurity region. Thereby, the electric field strength generated inside the active layer can be weakened more reliably, and as a result, the light leakage current can be more reliably suppressed.
[0135]
  The upper light-shielding layer is not particularly limited, but is formed along the step of the metal wiring layer disposed below the upper light-shielding layer so as to be active with the upper light-shielding layer in the portion without the metal wiring layer. It is preferable that the distance between the layers does not increase. As a result, light incident from an oblique direction can be more reliably shielded than when the upper light shielding layer is formed in a linear shape (flat plate shape). That is, in the portion where there is no metal wiring layer, the upper light shielding layer is disposed closer to the active layer, so that light incident from an oblique direction can be more reliably shielded.
[0136]
  The gate wiring layer disposed above the upper light shielding layer may be configured to be used as the third light shielding layer. As a result, it is possible to provide a light shielding layer having a simpler structure with one layer below the active layer and two layers above the active layer.
[0137]
  Further, the lower light shielding layer may be configured to be used as a metal wiring layer. As a result, the lower light-shielding layer disposed below the active layer is used as the gate wiring layer, so that light incident on the active layer can be shielded with a simpler configuration.
[0138]
  In addition, the material of each light shielding layer is not particularly limited as long as it has a light shielding effect, except when used in combination as a metal wiring layer or a gate wiring layer,(1)A single layer of Ta, Ti, W, Mo, Cr, Ni, polysilicon, or(2)MoSi₂, TaSi2, WSi₂CoSi₂, NiSi₂, PtSi, Pd₂S, HfN, ZrN, TiN, TAN, NbN, TiC, TaC, TiB₂Any single layer, or(3)the above(2)A multilayer structure in which any of the single layers is combined is preferable.
[0139]
  The liquid crystal display device according to the present invention described above includes a TFT or the like at a position corresponding to a portion where the metal wiring layer including the source wiring layer for inputting the data signal to the active layer and the gate wiring layer intersect. An active layer is provided.
[0140]
  That is, the position of the active layer is not limited to the position where the two wiring layers intersect (intersect). For example, Embodiments 1, 2 andReference example 1In this case, the active layer 35 is disposed at a position where the metal wiring layer 33 is not present. In this case, the light leakage current of the active layer 35 is suppressed by forming the upper light shielding layer 34 or the third light shielding layer 36 on the active layer 35 which is shielded by the metal wiring layer 33 in FIG. Such a configuration may be adopted.
[0141]
  In other words, the position of the active layer is included in the technical scope of the present invention as long as it is in a corresponding relationship with the part even if it is separated from the part where the two wiring layers intersect.
[0142]
  Moreover, the liquid crystal display device according to the present invention described above can also be expressed as follows.
That is, the liquid crystal display device according to the present invention is an active matrix type liquid crystal display device in which switching elements are arranged in a matrix. A light shielding layer is provided below the switching element, and the switching element is disposed on the metal wiring layer or above. A third light shielding layer is provided, and an upper light shielding layer is provided between the gate wiring layer and the metal wiring layer. The switching element preferably has an LDD structure.
[0143]
  Furthermore, in the liquid crystal display device according to the present invention, when the switching element has an LDD structure, the upper light shielding layer includes at least a junction portion between the source region and the source side low concentration impurity region, the source side low concentration impurity region, and the source side. Cover the junction between the low concentration impurity region and the channel region, the junction between the channel region and the drain side low concentration impurity region, the drain side low concentration impurity region, and the junction between the drain side low concentration impurity region and the drain region. It is the structure which forms.
In addition, the liquid crystal display device according to the present invention is configured to be formed in an S shape.
[0144]
  In the liquid crystal display device according to the present invention, the upper light-shielding layer, the lower light-shielding layer, and the third light-shielding layer are made of a single layer film such as a metal film (Ta, Ti, W, Mo, Cr, Ni) or polysilicon, MoSi₂, TaSi2, WSi₂CoSi₂, NiSi₂, PtSi, Pd₂S, HfN, ZrN, TiN, TAN, NbN, TiC, TaC, TiB₂Or a combination thereof.
Further, the liquid crystal display device according to the present invention has a configuration in which at least one of the upper and lower light shielding layers is used as a wiring.
[0145]
  Moreover, the manufacturing method of the liquid crystal display device according to the present invention described above can also be expressed as follows.
That is, in the method for manufacturing a liquid crystal display device according to the present invention, a lower light-shielding layer is formed on a transparent insulating substrate, and a semiconductor layer serving as an active layer of a thin film transistor is formed thereon via a first interlayer insulating film. Subsequently, after forming a gate insulating film, a gate electrode, and a gate wiring layer, an upper light shielding layer is formed through a second interlayer insulating film, and then a third interlayer insulating film and a metal wiring layer are formed. Further, a third light shielding layer is formed through a fourth interlayer insulating film.
[0146]
  According to the liquid crystal display device and the manufacturing method thereof, the light shielding layer is provided below the switching element, the third light shielding layer of the switching element is provided on the metal wiring layer or above, and the gate wiring layer and the metal wiring. It has a structure with an upper light-shielding layer between it and the light, and it can shield light that enters from the oblique direction and reaches the switching element as well as the vertical direction when viewed from the switching element. It can be greatly reduced.
[0147]
【The invention's effect】
  As described above, the liquid crystal display device according to the present invention has an active layer at a position corresponding to a portion where a metal wiring layer including a source wiring layer for inputting a data signal to the active layer and a gate wiring layer intersect. The liquid crystal display device includes a lower light shielding layer below the active layer and an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer above the active layer. .
[0148]
  Therefore, at least a lower light shielding layer is provided below the active layer, and an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is provided above the active layer. Thereby, there is an effect that the light leakage current can be surely suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like. Further, since the upper light shielding layer can be provided electrically independently from the gate wiring layer and the metal wiring layer, it is possible to reduce adverse effects on the electrical characteristics of the active layer.
[0149]
  Further, as described above, the liquid crystal display device according to the present invention includes a metal wiring layer including a source wiring layer for inputting a data signal to the active layer, and a gate wiring layer disposed below the metal wiring layer. In a liquid crystal display device having an active layer disposed below the gate wiring layer at a position corresponding to a position where the crossing and the lower layer are below the active layer, the lower light shielding layer is provided below the active layer, and the metal wiring is provided above the active layer. At least an upper light shielding layer disposed below the layer.May.
[0150]
  Therefore, at least a lower light shielding layer is provided below the active layer, and an upper light shielding layer disposed below the metal wiring layer including the source wiring layer is provided above the active layer. Thereby, there is an effect that the light leakage current can be surely suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like. Further, since the upper light shielding layer can be provided electrically independently from the gate wiring layer and the metal wiring layer, it is possible to reduce adverse effects on the electrical characteristics of the active layer.
[0151]
  As described above, the liquid crystal display device according to the present invention further includes a third light-shielding layer disposed above the upper light-shielding layer above the active layer.
[0152]
  Therefore, the structure is provided with one light-shielding layer at the bottom of the active layer and two light-shielding layers at the top, further reducing light incident directly on the active layer formation region or light incident from an oblique direction. There is an effect that can be made. Therefore, the light leakage current can be more reliably suppressed.
[0153]
  As described above, the liquid crystal display device according to the present invention has a configuration in which the upper light shielding layer is formed along the step of the gate wiring layer or the metal wiring layer disposed below the upper light shielding layer.
[0154]
  Therefore, even if either the gate wiring layer or the metal wiring layer is disposed below the upper light shielding layer, the upper light shielding layer is formed along the step of the gate wiring layer or the metal wiring layer as compared with the case where the upper light shielding layer is formed in a flat plate shape. The formation has an effect that a part of the light shielding layer can be brought closer to the active layer. Therefore, it is possible to more reliably shield light incident from an oblique direction and more reliably suppress light leakage current.
[0155]
  As described above, the liquid crystal display device according to the present invention has a configuration in which the third light shielding layer is used in combination as a metal wiring layer.
[0156]
  Therefore, since the third light shielding layer is used in combination as a metal wiring layer, the light incident on the active layer can be shielded with a simpler configuration.
[0157]
  In the liquid crystal display device according to the present invention, as described above, the active layer further includes a channel region, a source side high concentration impurity region and a drain side high concentration impurity region sandwiching the channel region, and the channel region and the source side. In this configuration, low-concentration impurity regions are respectively formed between the high-concentration impurity regions and between the channel region and the drain-side high-concentration impurity regions.
[0158]
  Therefore, the active layer includes a channel region, a source-side high concentration impurity region and a drain-side high concentration impurity region sandwiching the channel region, and between the channel region and the source-side high concentration impurity region, and between the channel region and the drain. Since it has an LDD structure (Lightly doped drain) structure in which low-concentration impurity regions are respectively formed between the side high-concentration impurity regions, there is an effect that the electric field strength generated in the active layer can be weakened. Therefore, the light leakage current can be further suppressed.
[0159]
  As described above, the liquid crystal display device according to the present invention has a configuration in which the upper light shielding layer is formed so as to cover at least the junction portion of each of the above-described regions constituting the active layer and the low-concentration impurity region. .
[0160]
  Therefore, when the active layer has an LDD structure, the upper light-shielding layer is formed so as to cover at least the junction portion of each of the above-described regions and the low-concentration impurity region. Therefore, there is an effect that the electric field strength generated in the active layer can be weakened more surely. Therefore, the light leakage current can be more reliably suppressed.
[0161]
  Further, in the liquid crystal display device according to the present invention, as described above, each of the light shielding layers described above is used in combination as a metal wiring layer or a gate wiring layer.(1)A single layer of Ta, Ti, W, Mo, Cr, Ni, polysilicon, or(2)MoSi₂, TaSi2, WSi₂CoSi₂, NiSi₂, PtSi, Pd₂S, HfN, ZrN, TiN, TAN, NbN, TiC, TaC, TiB₂Any single layer, or(3)the above(2)It is the structure which is the multilayered structure which combined either of these single layers.
[0162]
  In addition, the present inventionReference exampleAs described above, the method for manufacturing a liquid crystal display device according to the present invention includes an active layer at a position corresponding to a portion where a metal wiring layer including a source wiring layer for inputting a data signal to the active layer and a gate wiring layer intersect. A method of manufacturing a liquid crystal display device comprising: at least a step of forming an upper light-shielding layer disposed on an active layer between the step of forming a metal wiring layer and the step of forming a gate wiring layer InMay.
[0163]
  Therefore, an upper light shielding layer disposed between the metal wiring layer and the gate wiring layer is formed on the active layer. That is, the upper light shielding layer is formed closer to the upper part of the active layer than in the conventional case. Thereby, there is an effect that the light leakage current can be surely suppressed without reducing the pixel aperture ratio necessary for projecting the transmitted light onto a screen or the like.
[0164]
  In addition, as described above, the method for manufacturing a liquid crystal display device according to the present invention includes a metal wiring layer including a source wiring layer for inputting a data signal to the active layer, and a lower layer than the metal wiring layer. In a manufacturing method of a liquid crystal display device including an active layer disposed below a gate wiring layer at a position corresponding to a portion where the gate wiring layer intersects, a step of forming a lower light shielding layer on the substrate, and a lower light shielding Forming an active layer via a first insulating layer on the substrate on which the layer is formed; forming a gate wiring layer via a second insulating layer on the first insulating layer and the active layer; Forming an upper light shielding layer on the second insulating layer and the gate wiring layer via the third insulating layer; and forming a fourth insulating layer on the third insulating layer and the upper light shielding layer; A metal wiring layer on the fourth insulating layer And forming a process including at least.
[0165]
  Therefore, a lower light shielding layer is formed below the active layer via the first insulating layer. Further, an upper light shielding layer is formed on the active layer between the gate wiring layer via the third insulating layer and the metal wiring layer via the fourth insulating layer.
[0166]
  As a result, the distance between the upper light-shielding layer and the active layer can be set smaller than the distance between the metal wiring layer and the active layer, so that the pixel aperture ratio required for projecting transmitted light onto a screen or the like is reduced. There is an effect that the light leakage current can be reliably suppressed.
[Brief description of the drawings]
FIG. 1 is one of the present inventionReference exampleIt is a longitudinal cross-sectional view of the liquid crystal display device concerning.
2 is a cross-sectional view taken along the line A-A ′ of the liquid crystal display device illustrated in FIG. 1;
3A to FIG. 3D are longitudinal sectional views showing manufacturing steps of the liquid crystal display device shown in FIG. 1, and FIG. 3A is a lower light shielding layer on the substrate. FIG. 3B shows a first insulating layer forming step, FIG. 3C shows an active layer forming step, and FIG. 3D shows a second insulating layer and gate wiring layer forming step. It is shown.
4A to FIG. 4C are longitudinal sectional views showing manufacturing steps subsequent to the manufacturing step shown in FIG. 3, and FIG. 4A is a step of forming a low concentration impurity region. FIG. 4B shows a process for forming a high-concentration impurity region, and FIG. 4C shows a process for forming a third insulating layer and an upper light shielding layer.
5 (a) to 5 (c) are longitudinal sectional views showing manufacturing steps subsequent to the manufacturing step shown in FIG. 4, and FIG. 5 (a) shows a fourth insulating layer and metal. The wiring layer forming step, FIG. 5B shows the nitride layer and fifth insulating layer forming step, and FIG. 5C shows the third light shielding layer forming step.
6 is a B-B ′ cross-sectional view of the liquid crystal display device shown in FIG.
FIGS. 7A and 7B are longitudinal sectional views showing manufacturing steps of the liquid crystal display device according to the embodiment of the present invention, and FIG. 7A is a third insulating layer; FIG. 7B shows a step of forming the third insulating layer and the upper light shielding layer.
FIG. 8 is a longitudinal sectional view showing a manufacturing process of a liquid crystal display device according to another embodiment of the present invention, and shows a process of forming a third insulating layer and an upper light shielding layer.
FIG. 9 shows another embodiment of the present invention.Reference exampleFIG. 10 is a longitudinal sectional view showing a manufacturing process of the liquid crystal display device according to the embodiment, and shows a process of forming a third insulating layer and an upper light shielding layer.
FIG. 10 is a longitudinal sectional view of a conventional liquid crystal display device.
FIG. 11 is a longitudinal sectional view of another conventional liquid crystal display device.
FIG. 12 is a longitudinal sectional view of another conventional liquid crystal display device.
FIG. 13 is a longitudinal sectional view of another conventional liquid crystal display device.
FIG. 14 is a longitudinal sectional view of another conventional liquid crystal display device.
FIG. 15 (a) is a diagram for explaining a range in which an upper light shielding layer is formed in a liquid crystal display device according to an embodiment of the present invention, and FIG. 15 (b) is another embodiment of the present invention. It is a figure for demonstrating the said range in the liquid crystal display device which concerns on a form.
[Explanation of symbols]
  16 Contact hole
  32 Gate wiring layer
  33 Metal wiring layer
  33a Source wiring layer
  33b Drain wiring layer
  34 Upper shading layer
  34a Source side upper light shielding layer
  34b Drain side upper light shielding layer
  35 Active layer
  35a Low concentration impurity region
  35b Low concentration impurity region
  35c channel region
  35d source region (source side high concentration impurity region)
  35e Drain region (drain side high concentration impurity region)
  36 3rd light shielding layer
  38 Insulating layer
  40 substrates
  41 Lower shading layer
  42 Liquid crystal display device
  43 First insulating layer
  44 Second insulating layer
  45 Third insulating layer
  45a Convex
  46 4th insulating layer
  47 Fifth insulating layer
  51 Insulation layer
  55-62 joint

Claims (12)

In the liquid crystal display device including a metal wiring layer, the active layer at a position where the gate wiring layer corresponding to the portion that intersects containing the source wiring layer for inputting a data signal to the active layer,
The lower light-shielding layer in the lower portion of said active layer,
An upper shielding layer disposed between the metal wiring layer and the gate wiring layer on top of said active layer,
Between the gate wiring layer and the upper shielding layer, an insulating layer having a convex shape, an insulating layer corners having a smooth curved in a convex portion of the insulating layer,
At least ,
Depositing the insulating layer 50-300 nm;
The liquid crystal display device, wherein the upper light shielding layer is formed in an S shape along a step of the gate wiring layer disposed below the upper light shielding layer . The liquid crystal display device according to claim 1, further comprising a third light-shielding layer disposed above the upper light-shielding layer above the active layer. The third light-shielding layer, the liquid crystal display device according to claim 2, characterized in that it is used together as the metal wiring layer. Each of the light shielding layers is (1) a single layer of Ta, Ti, W, Mo, Cr, Ni, or polysilicon, or (2) MoSi ₂ , TaSi ₂ , WSi ₂ , CoSi ₂ , NiSi ₂ , PtSi. , Pd ₂ S, Ru multilayer der that combine any of the HfN, ZrN, TiN, TAN, NbN, TiC, TaC, either a single layer of TiB _2, or (3) a single layer of the above (2) The liquid crystal display device according to claim 1 , wherein the liquid crystal display device is a liquid crystal display device. The active layer includes a channel region, a source-side high concentration impurity region and a drain-side high concentration impurity region sandwiching the channel region, and between the channel region and the source-side high concentration impurity region, and between the channel region and the drain side high concentration impurity region. between the doped regions, the liquid crystal display device according to claim 1, any one of 4, wherein that you have no an LDD structure low concentration impurity regions are formed respectively. The upper light shielding layer, at least, a liquid crystal display device according to claim 5, characterized in that it is formed so as to cover the joint portion and the low-concentration impurity regions of the respective regions of the active layer. In order to apply a voltage to the upper light shielding layer, a liquid crystal display device according to the upper shielding layer to any one of claims 1 to 6, characterized in that extending along the gate wiring layer. 8. The liquid crystal display device according to claim 1 , wherein the upper light shielding layer is formed separately so as not to be formed in a range where light can be shielded by the gate wiring layer. 9. The insulating layer having a sidewall shape having curved convex shapes in the outer direction of the gate wiring layer on both sides of the gate wiring layer . 10. The liquid crystal display device described. A metal wiring layer including a source wiring layer for inputting data signals to the active layer than the gate wiring layer at a position where the gate wiring layer disposed lower than said metal wiring layer corresponding to the portion crossing In a method for manufacturing a liquid crystal display device having an active layer disposed below,
Forming a lower light shielding layer on the substrate;
Forming the active layer on the substrate on which the lower light-shielding layer is formed via a first insulating layer;
Forming the gate wiring layer on the first insulating layer and the active layer via the second insulating layer;
An insulating layer having a convex shape on the second insulating layer and the gate wiring layer, wherein the upper light-shielding layer is formed via the third insulating layer having a smooth curve at the corner of the convex portion of the insulating layer. Forming step;
Forming a fourth insulating layer on the third insulating layer and the upper light shielding layer;
Forming at least the metal wiring layer on the fourth insulating layer,
Depositing about 50 to 300 nm of the insulating layer;
The method of manufacturing a liquid crystal display device , wherein the upper light shielding layer is formed in an S shape along a step of the gate wiring layer disposed below the upper light shielding layer . The above steps for forming the upper light shielding layer include :
Depositing an insulating layer to be a third insulating layer on the second insulating layer and the gate wiring layer, and forming a third insulating layer by an etching process ;
The method for manufacturing a liquid crystal display device according to claim 10, further comprising: depositing a light shielding layer to be an upper light shielding layer on the third insulating layer , and forming the upper light shielding layer by an etching process . The above steps for forming the upper light shielding layer include:
Forming a sidewall-shaped insulating layer having a curved convex shape in the outer direction of the gate wiring layer on both sides of the gate wiring layer facing the wiring direction of the metal wiring layer;
Forming a third insulating layer on the second insulating layer , the gate wiring layer, and the sidewall-shaped insulating layer;
The method for manufacturing a liquid crystal display device according to claim 10 , further comprising: depositing a light shielding layer to be an upper light shielding layer on the third insulating layer and forming the upper light shielding layer by an etching process.

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