JP2003255376A - Liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection/transmission type liquid crystal display in which two pixel electrodes can be formed not by a photolithographic process but by a dry process. <P>SOLUTION: The reflection/transmission type liquid crystal display has a substrate 40 transmitting light, a pixel electrode for reflection 10 which is patterned in a prescribed shape on the substrate 40 and which is provided with an opening 10w and a pixel electrode for light transmission 12 which is patterned in a prescribed shape and which is brought into contact with the pixel electrode 10 and which covers the opening 10w and its peripheral part, a counter electrode 62 which is arranged opposite to the pixel electrode for reflection 10 and the pixel electrode for light transmission 12 and liquid crystal 62 which is interposed among the pixel electrode 10, the pixel electrode 12 and the counter electrode 62. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display devices are used in many products such as mobile phones, mobile terminals, notebook type personal computers, and camera-integrated video tape recorders as an essential item in the age of multimedia information. In particular, Low-Temperature Poly-S
iliconThin-Film-Transistor liquid-Crystal-Display)
Since TFT elements that are drive circuits can be integrated on a glass substrate, high definition and low power consumption are possible, and it is expected that the application will be expanded by integrating various circuits in the future. . Also, low temperature polysilicon T
In mass-producing FT type high-definition liquid crystal panels, there is an increasing demand for further cost reduction.

When a liquid crystal display device is classified according to how light is used, the liquid crystal display device is classified into a transmissive type that uses a backlight, a reflective type that uses external light, and a reflective / transmissive type that has both functions. It The reflective / transmissive type uses a backlight in a dark place and reflects external light from a pixel electrode in a bright place, thereby realizing high brightness and power saving.

FIG. 9 is a plan view showing an example of the structure of a drive substrate of a reflective / transmissive liquid crystal display device. This liquid crystal display device is a so-called bottom gate type low temperature polysilicon T.
It is an FT-LCD. In FIG. 9, the display pixel portion 101
Are arranged in a matrix, and the display pixel unit 1
01 is the reflection pixel electrode 102 and this reflection pixel electrode 1
The pixel electrode 103 for transmission is formed under 02.
Each display pixel portion 101 includes a transmissive portion W, and
A TFT element 104 is formed at one corner of each display pixel portion 101. The TFT element 104 has a gate line 10
6, the signal line 105, the reflective pixel electrode 102, and the transmissive pixel electrode 103 are electrically connected to each other.

FIG. 10 shows a TFT element 10 of a liquid crystal display device.
9 is a cross-sectional view showing the cross-sectional structure of FIG.
It is sectional drawing of the A line direction. FIG. 11 is a cross-sectional view showing the structure around the transmissive portion W of the liquid crystal display device, which is a cross-sectional view taken along the line BB in FIG. TF shown in FIG.
In the T element 104, a gate electrode 107 made of a conductive material such as Mo is formed in a predetermined pattern on an insulating and transparent substrate 110 made of a glass plate or the like. The gate electrode 107 is the gate line 10 described above.
6 and is electrically connected to a storage capacitor wiring (not shown).

A barrier insulating film 112 made of silicon nitride is formed on the gate electrode 107 so as to cover the gate electrode 107, and a gate insulating film 113 made of silicon oxide is formed on the barrier film 112. There is. A polysilicon layer 108 having a predetermined pattern is formed on the gate insulating film 113. The polysilicon layer 108 is electrically connected to the signal line 105, the reflection pixel electrode 102, and the transmission pixel electrode 103 through a contact hole (not shown). A stopper layer 1 for covering the portion of the polysilicon layer 108 located on the gate electrode 107 is formed on the polysilicon layer 108.
15 is formed. In the polysilicon layer 108, an LDD (Lightly Doped Drain) region and an N ⁺ region are formed and activated by a known method. An interlayer insulating film 116 made of silicon oxide is formed on the gate insulating film 113 so as to cover the polysilicon layer 108 and the stopper layer 115, and an interlayer insulating film 117 made of silicon nitride is formed on the interlayer insulating film 116. Has been formed.

A diffusion plate 118 having an uneven surface is formed on the interlayer insulating film 117. This diffuser plate 118
Is provided to generate unevenness on the reflective pixel electrode 102 formed in the upper layer and diffuse the light incident on the reflective pixel electrode 102 to improve the brightness. A flattening layer 119 is formed on the diffusion plate 118. The flattening layer 119 is provided to smooth the unevenness of the diffusion plate 118 to the extent that the reflective pixel electrode 102 is easily formed.

The transparent pixel electrode 1 is formed on the flattening layer 119.
03 is formed, and the reflection pixel electrode 102 is formed on the transmission pixel electrode 103. Transmission pixel electrode 103
Is formed of a transparent film such as an ITO (Indium Tin Oxide) film, and the reflective pixel electrode 102 is formed of a reflective film of Al or the like.

The substrate 110 to the reflective pixel electrode 102 are formed by a series of processes to form a drive substrate for driving the liquid crystal display device. As shown in FIG. 10, the counter electrode 1 made of a transparent film such as an ITO film is provided on the front surface side of the drive substrate.
34, a color filter 135, a retardation plate 136, and a polarizing plate 137 are provided, the liquid crystal 130 is sealed between the reflection pixel electrode 102 and the counter electrode 134, and the retardation plate 133 is provided on the back surface side of the drive substrate. A polarizing plate 132 and a planar light source 131 are provided. As shown in FIG. 10, external light OL incident from the outside toward the polarizing plate 137 is reflected by the reflection pixel electrode 102 through the liquid crystal 130 and can be output to the outside again through the liquid crystal 130. On the other hand, the light BL from the planar light source 131 is reflected by the reflection pixel electrode 1
02 is present, it is not output to the polarizing plate 137 side.

On the other hand, as shown in FIG. 11, the barrier film 112, the gate insulating film 113, the interlayer insulating films 116 and 117, the diffusion plate 118 and the planarizing layer 119 laminated on the substrate 110 are formed on the substrate 110. A reaching hole H is formed. The transmissive pixel electrode 103 is formed on the planarization layer 119, and is formed so as to cover the surface of the substrate 110 that is the bottom of the hole H and the inner peripheral surface of the hole H.
Further, the reflection pixel electrode 102 formed on the transmission pixel electrode 103 has a window 102w formed at the bottom of the hole H. Therefore, as shown in FIG. 11, the light BL from the planar light source 131 is transmitted through the window 102w to the polarizing plate 1
It is possible to output to the 37 side.

[0011]

In order to form the reflective pixel electrode 102 and the transmissive pixel electrode 103 of the liquid crystal display device having the above structure, first, a transparent conductive film is formed on the planarizing layer 119 in a vacuum atmosphere. After forming the film, the transparent pixel electrode 103 is formed by patterning in the predetermined pattern shown in FIG. 9 by a photolithography process. Next, after forming a reflective conductive film on the transmissive pixel electrode 103 in a vacuum atmosphere, patterning is performed by a photolithography process to form the reflective pixel electrode 102. The photolithography process consists of many processes such as pre-treatment cleaning, resist coating, pre-baking, exposure, development and post-baking. Therefore, it is necessary to form the reflective pixel electrode 102 and the transmissive pixel electrode 103 in two steps.
If two photolithography processes are required, the number of processes is large in a mass production factory, a large number of large coater developers are required, and the equipment cost increases, which is a factor that hinders cost reduction of products. Therefore, it has been desired to reduce the number of steps for forming the reflective pixel electrode 102 and the transmissive pixel electrode 103. Further, in the photolithography process, since a large amount of chemical liquid is used, it is desirable to form the reflective pixel electrode 102 and the transmissive pixel electrode 103 by a so-called dry process from the viewpoint of resource saving and prevention of environmental pollution. Was there.

The present invention has been made in view of the above-mentioned problems, and an object thereof is a method of manufacturing a reflection / transmission type liquid crystal display device capable of forming pixel electrodes without a photolithography process and a reflection / transmission type liquid crystal display device. It is to provide a transmissive liquid crystal display device.

[0013]

A liquid crystal display device according to the present invention comprises a substrate which transmits light and a conductive reflective film which is patterned on the substrate in a predetermined shape, and which is provided with an opening through which light passes. Pixel electrode and a conductive transparent film patterned into a predetermined shape, the pixel electrode for contact being in contact with the pixel electrode for reflection and covering at least the opening, the pixel electrode for reflection and the pixel for transmission. The liquid crystal display device includes a counter electrode arranged to face the electrode, and a liquid crystal interposed between the reflective pixel electrode and the transmissive pixel electrode and the counter electrode.

The conductive transmissive film is made of a material in which the energy density of the laser light required to be selectively removed by the processing using the laser light is smaller than that of the conductive reflective film.

Preferably, the conductive transparent film is made of a material having a linear expansion coefficient smaller than that of the conductive reflective film.

More preferably, the transmissive pixel electrode is
Only the opening of the reflective pixel electrode and the peripheral portion of the opening are covered.

According to the method of manufacturing a liquid crystal display device of the present invention, a transparent pixel substrate is provided with a pixel electrode for transmission that transmits light that is patterned in a predetermined shape and an aperture that allows light to pass through, and a pixel electrode for reflection that reflects light. In the method of manufacturing a liquid crystal display device including :, at least one of the patterning of the transmissive pixel electrode and the reflective pixel electrode is performed by processing using a laser beam.

Preferably, the method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming a conductive reflective film on a substrate which transmits light, and a step of processing the conductive reflective film with a laser beam to give a predetermined shape. And forming a reflective pixel electrode having an opening through which light passes, forming a conductive transparent film on the substrate so as to cover the reflective pixel electrode, and the conductive transparent film. Is patterned into a predetermined shape by processing using a laser beam, and a transmissive pixel electrode that covers at least the opening is formed.

According to the present invention, a reflective pixel electrode made of a conductive reflective film and a transmissive electrode made of a conductive transmissive film are provided,
At least one of these patterning is performed by processing using laser light. This reduces the photolithography process. In addition, by using a material for the conductive transparent film, which has a smaller energy density of laser light than the conductive reflective film necessary for selective removal by processing using the laser light, When processed by, the lower conductive reflective film is not removed. Furthermore, by using a material with a linear expansion coefficient smaller than that of the conductive reflective film for the conductive transparent film, when the conductive transparent film is processed by laser light, due to the difference in thermal expansion, the conductive reflective film and the conductive transparent film are Strain occurs at the interface with the film, and only the upper conductive layer having a small linear expansion coefficient is removed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a configuration of a drive substrate in a liquid crystal display device according to an embodiment of the present invention. As shown in FIG. 1, a driving substrate 1 includes pixel electrode portions 2 arranged in a matrix and TFT (Thin Film Transistor) elements 3 provided for each pixel electrode portion 2.
Has 0 and. A signal line 6 and a gate line 5 are provided between the pixel electrode portions 2.

The pixel electrode portion 2 includes a reflective pixel electrode 10 and
The transparent pixel electrode 12 is formed on the reflective pixel electrode 10. Further, an opening 10w is formed in the reflective pixel electrode 10, and the transmissive portion 3 is constituted by the opening 10w and the transmissive pixel electrode 12.

The TFT element 30 has a gate electrode 7 and a polysilicon layer 8 arranged so as to intersect the gate electrode 7. The gate electrode 7 is electrically connected to the gate line 6. One end of the polysilicon layer 8 is electrically connected to the signal line 5, and the other end is reflective pixel electrode 10
Electrically connected to. The gate line 6 is a TFT
The signal line 5 is a wiring for supplying a scanning signal to the element 30, and the signal line 5 is a wiring for applying a signal voltage to the TFT element 30.

FIG. 2 is a cross-sectional view showing a cross-sectional structure around the TFT element 30 of the liquid crystal display device according to the present embodiment, and shows a cross section taken along the line AA in FIG. 3 is a cross-sectional view showing a cross-sectional structure around the transmissive portion 3 of the drive substrate of the liquid crystal display device according to the present embodiment, and is a cross-sectional view taken along the line BB in FIG. As shown in FIG. 2 and FIG. 3, the liquid crystal display device according to the present embodiment includes a drive substrate 1, a counter electrode 62, a color filter 64, and a counter electrode 62 which are arranged to face the electrode formation surface side of the drive substrate 1. It has a retardation plate 66 and a polarizing plate 68, and a retardation plate 70, a polarizing plate 72 and a planar light source 74 arranged on the back surface side of the drive substrate 1.

The drive substrate 1 includes a substrate 40 and a gate electrode 7
A barrier film 44, a gate insulating film 46, a polysilicon layer 8, a stopper layer 50, and interlayer insulating films 48 and 52.
, Diffusion plate 54, flattening layer 56, and reflection pixel electrode 1
0 and the pixel electrode 12 for transmission.

The substrate 40 is formed of a material that transmits light, such as a glass material. The gate electrode 7 is patterned on the substrate 40 together with the gate line 6 described above. The gate electrode 7 is obtained by, for example, forming a conductive material such as Mo (molybdenum) on the substrate 40 by sputtering and patterning the Mo thin film by, for example, photolithography.

The barrier film 44 is formed on the substrate 40 so as to cover the gate electrode 7. This barrier film 44
Is a silicon nitride film formed on the substrate 40 by, for example, a plasma CVD method. Gate insulating film 46
Is formed on the barrier film 44 and is, for example, a film of silicon oxide formed by a plasma CVD method.

The polysilicon layer 8 is patterned on the gate insulating film 46. This polysilicon layer 8 is
For example, after amorphous silicon is formed on the gate insulating film 46 by the plasma CVD method, an annealing process is performed to remove hydrogen contained in the amorphous silicon and convert it to polysilicon. For example, it is obtained by patterning by photolithography. In addition, impurities such as phosphorus (P) are injected into both sides of the stopper layer 50 of the polysilicon layer 8 at a predetermined concentration and activated to activate LDD (Lightly Dop).
ed Drain) region and N ⁺ region are formed.

The stopper layer 50 is made of, for example, silicon oxide. The stopper layer 50 is formed, for example, by forming a silicon oxide film on the gate insulating film 46 so as to cover the polysilicon layer 8 by a CVD method, and then patterning this silicon oxide by self-alignment using the gate electrode 7 as a mask. can get. Therefore, the stopper layer 50 covers the portion of the polysilicon layer 8 located on the gate electrode 7. The LDD region is formed by ion-implanting impurities using the stopper layer 50 as a mask. After the stopper layer 50 and the periphery of the stopper layer 50 are masked with a photoresist, impurities are ion-implanted into the polysilicon layer 8 to form an N ⁺ region. After that, an annealing process is performed to activate the impurities.

The interlayer insulating film 48 is formed on the gate insulating film 46 so as to cover the stopper layer 50 and the polysilicon layer 8. The interlayer insulating film 48 is formed of, for example, silicon oxide by the CVD method. The interlayer insulating film 52 is formed on the interlayer insulating film 48. The interlayer insulating film 48 is formed of, for example, silicon nitride by the CVD method.

The diffusion plate 54 is formed on the interlayer insulating film 52. The diffusion plate 54 has irregularities on its surface. Due to the unevenness, the unevenness is formed on the reflection electrode 10 formed on the upper layer of the diffusion plate 54, and the light incident on the reflection electrode 10 is diffused to improve the brightness. The diffusion plate 54 is obtained by applying a resist such as acrylic resin on the interlayer insulating film 52 by spin coating.
It can be obtained by fixing the resist on the underlayer by a post-baking treatment, removing the solvent, and forming irregularities on the surface of the resist. The unevenness is processed on the resist surface by, for example, photolithography or laser processing.

The flattening layer 56 is formed on the diffusion plate 54, and is provided to smooth the unevenness of the surface of the diffusion plate 54 and facilitate the fixing of the reflective pixel electrode 10. Therefore, the surface of the flattening layer 56 is smoother than the surface of the diffusion plate 54.

The reflective pixel electrode 10 is patterned on the flattening layer 56. The reflective pixel electrode 10 is
For example, it is formed of a conductive reflective film such as Al.
As will be described later, the reflective pixel electrode 10 is patterned by performing an ablation process using a laser beam, which will be described later, after a conductive reflective film is sputtered on the flattening layer 56.

Further, as shown in FIG. 3, the reflective pixel electrode 10 has an opening 10w formed in the transmissive portion 3. The reflective pixel electrode 10 is provided on the substrate 4 in the transmissive portion 3.
The barrier film 42, the gate insulating film 46, the interlayer insulating films 48 and 52, the diffusion plate 54, and the flattening layer 56 which are stacked on the surface of the substrate 40 which is the bottom of the hole H reaching the substrate 40 and It is formed so as to cover the inner peripheral surface of the hole H. Reflection pixel electrode 10 formed on the surface of the substrate 40
An opening 10w is formed in the. The method of forming the reflective pixel electrode 10 will be described later.

The transmissive pixel electrode 12 is formed on the reflective pixel electrode 10 formed on the surface of the substrate 40, and covers only the opening 10w and the peripheral portion of the opening 10w. The transmissive pixel electrode 12 is formed of, for example, ITO (Ind
It is formed by a conductive transparent film such as ium tin oxide. The method of forming the transmissive pixel electrode 12 will be described later.

The counter electrode 62, the color filter 64, the retardation plate 66 and the polarizing plate 68 are integrated to form the drive substrate 1.
Is arranged so as to face the pixel electrode formation side. The counter electrode 62 is
It is formed of a conductive transmissive film such as ITO (Indium Tin Oxide) and forms an electric field between the reflective pixel electrode 10 and the transmissive pixel electrode 12.

The polarizing plates 68 and 72 convert the incident light into linearly polarized light. The retardation plates 66 and 70 perform optical compensation for converting linearly polarized light incident through the polarizing plate 68 or 72 into circularly polarized light in order to improve the contrast of the liquid crystal display device and reduce or prevent the color change. The color filter 64 is formed by forming a fine colored layer of three primary colors of red (R), green (G), and blue (B) and a light shielding layer called a black matrix in a predetermined pattern. The planar light source 74 has, for example, a light source such as a cold cathode fluorescent tube built therein, and the planar light B
L is output toward the substrate 40 side.

The liquid crystal 60 sealed between the counter electrode 62 and the reflective pixel electrode 10 and the transmissive pixel electrode 12 includes:
For example, twisted nematic (TN) liquid crystal is used.

In the liquid crystal display device having the above structure, the polarizing plate 68 is used.
External light OL incident from the side is polarized plate 68, retardation plate 6
6, passes through the color filter 64 and the counter electrode 62 and enters the reflection pixel electrode 10, and the reflection pixel electrode 10
Is reflected by and is output again from the polarizing plate 68 to the outside. Since the surface of the reflective pixel electrode 10 has irregularities due to the irregularities of the diffusion plate 54, the external light OL incident on the reflective pixel electrode 10 is scattered and the brightness of the screen is improved. Further, since the transmissive pixel electrode 12 does not exist on the reflective pixel electrode 10 except the transmissive portion 3, the reflection of the external light OL incident on the reflective pixel electrode 10 is not hindered and the brightness is further increased. Screen is obtained.

On the other hand, the light BL output from the planar light source 74
2 is blocked by the reflective pixel electrode 10 in the region where the reflective pixel electrode 10 exists as shown in FIG. 2 and is not output from the polarizing plate 68 to the outside, but as shown in FIG.
The light BL that has entered the transmissive pixel electrode 12 passes through the transmissive pixel electrode 12, and the counter electrode 62, the color filter 64,
It is output to the outside through the phase difference plate 66 and the polarizing plate 68. As a result, by using the planar light source 74 in a dark place and reflecting the external light by the reflection pixel electrode 10 in a bright place,
A liquid crystal display device with high brightness and low power consumption can be obtained.

Next, a method of forming the above-mentioned reflective pixel electrode 10 and transmissive pixel electrode 12 will be described. Figure 4
FIG. 3 is a diagram showing an example of a schematic configuration of a laser processing apparatus used for patterning the reflective pixel electrode 10 and the transmissive pixel electrode 12. The laser processing apparatus 200 shown in FIG. 4 includes a laser light source 201 and a plurality of mirrors 202, 203, 20.
4, a beam shaper 205, a mask 206, a reduction projection lens 207, and a stage 208.

The laser light source 201 outputs a laser beam LB. By the laser beam LB output from the laser light source 201, the processing surface 210 of the processing object 210 is processed.
f is processed. As the laser light source 1, for example, an excimer laser or a YAG laser is used. There are a plurality of types of excimer lasers having different laser media. As the laser medium, XeF (351
nm), XeCl (308 nm), KrF (248n)
m), ArF (193 nm) and F ₂ (157 nm). The excimer laser is greatly different from the YAG laser (1.06 μm) and the CO ₂ laser (10.6 μm) that perform processing using thermal energy in that the oscillation wavelength is in the ultraviolet range. The excimer laser essentially oscillates only in pulses, has a pulse width of about 20 ns and the laser beam is rectangular in shape. Further, the excimer laser performs a process called ablation, which is less susceptible to the thermal effect of photochemically dissociating the direct bond, so that the edge of the surface to be processed is extremely sharp. On the other hand, in the YAG laser and the CO ₂ laser, the processed portion is melted and then evaporated, so that the peripheral portion is rounded by the influence of heat and the end face is not clean. Further, the excimer laser has an initial beam cross section of about 10 × 10 mm, and a relatively large area is collectively formed by increasing the area and the area of this laser beam by a beam shaper described later. Can be processed. Therefore, the excimer laser is suitable for simultaneously processing a large area.

The beam shaper 205 expands and shapes the laser beam LB from the laser light source 201 reflected by the mirrors 202 and 203, and outputs it to the mirror 204.

The mask 206 has a predetermined pattern for passing the laser beam LB which is shaped by the beam shaper 205 and reflected by the mirror 204. This mask 206
For example, a mask formed of a metal material, a mask formed of a transparent glass material or a transparent resin, a mask formed of a dielectric material, or the like is used.

The reduction projection lens 207 reduces the laser beam LB that has passed through the pattern of the mask 206 by a predetermined magnification to reduce the surface 2 to be processed of the processing object 210 on the stage 208.
Project to 10f.

The stage 208 has a reduction projection lens 207.
The reduction projection lens 20 so that the laser beam LB projected from the object is focused on the surface 210f to be processed of the processing object 210.
It is arranged with respect to 7. The stage 208 is provided with a fixing means such as a vacuum chuck for fixing the object to be processed, and applies the laser beam LB to the object to be processed 21.
Irradiate a desired position on the processed surface 210f of 0, and
The laser beam LB can be moved and positioned in the x, y, z and θ directions so that the laser beam LB can be focused on the processed surface 210f.

In the laser processing apparatus 200 having the above structure, the surface 210f of the processing object 210 is irradiated with the laser beam LB having a predetermined pattern defined by the mask 206,
The processed surface 210f is ablated.

Next, patterning of the reflective pixel electrode 10 and the transmissive pixel electrode 12 using the laser processing apparatus 200 will be described. In FIG. 5, in the transparent portion 3 of the drive substrate 1, a hole H is formed in the barrier film 42, the gate insulating film 46, the interlayer insulating films 48 and 52, the diffusion plate 54, and the flattening layer 56, which are stacked on the substrate 40, by etching. After the formation, the conductive reflection film 11 is formed on the flattening layer 56. The conductive reflective film 11 is made of, for example, Al.
It is formed by sputtering a metal material such as.

Next, the drive substrate 1 in the state shown in FIG. 5 is set on the stage 208 of the laser processing apparatus 200, and further, the mask 2 necessary for forming the reflective pixel electrode 10.
06 is set in the laser processing apparatus 200.

When the laser beam LB having a predetermined pattern is applied to the conductive reflection film 11 by the laser processing apparatus 200 at an energy density required for removing the conductive reflection film 11,
The conductive reflection film 11 is selectively removed, and as shown in FIG. 6, the reflection pixel electrode 10 having the opening 10w is formed. Although not shown, this laser processing also simultaneously processes the gap between the adjacent reflective pixel electrodes 10.

Next, the reflective pixel electrode 10 shown in FIG.
The drive substrate in the state where is formed is carried out from the laser processing apparatus 200, and as shown in FIG. 7, the conductive transparent film 13 is formed so as to cover the reflective pixel electrode 10. Here, as the material for forming the conductive transparent film 13, one having a smaller energy density of the laser beam LB required for selective removal in the laser processing apparatus 200 than the material for forming the conductive reflective film 11 is used. To use. Further, a material having a linear expansion coefficient smaller than that of the conductive reflective film 11 is used as a material for forming the conductive transparent film 13. Specifically, for example, when Al is used as the material for forming the conductive reflective film 11, ITO is used for the conductive transmissive film 13. The coefficient of linear expansion of Al is about 2.37 × 10 ⁻⁵ / K, the coefficient of linear expansion of ITO is about 5 × 10 ⁻⁶ / K, and Al is about 5 times larger than ITO.

When the conductive transparent film 13 is formed so as to cover the reflective pixel electrode 10, the conductive transparent film 13 covers the opening 10w of the reflective pixel electrode 10 as shown in FIG. It comes into contact with the surface of 40.
Although not shown, the conductive transmissive film 13 is also formed between the gaps between the adjacent reflective pixel electrodes 10.

Next, the drive substrate in the state shown in FIG. 7 is set on the stage 208 of the laser processing apparatus 200, and the mask 20 necessary for patterning the transmissive pixel electrode 12 is formed.
Set 6.

In the above state, the laser processing device 20
0, as shown in FIG. 8, the laser beam LB having a predetermined pattern is applied to the conductive transparent film 13 by the conductive transparent film 13.
Irradiation with the energy density required for the removal. As described above, the energy density of the laser beam LB is smaller than the energy density required to remove the conductive reflective film 11.

At this time, the laser beam L having a predetermined pattern
When B is irradiated to the conductive transparent film 13 made of ITO,
Reflection pixel electrode 1 made of conductive transparent film 13 and Al
The temperature of the irradiation region of the 0 laser beam LB rises, and thermal expansion occurs in the conductive transmissive film 13 and the reflective pixel electrode 10. Since ITO, which is the material for forming the conductive transparent film 13, has a smaller linear expansion coefficient than Al, which is the material for forming the reflective pixel electrode 10, the conductive transparent film 13 and the reflective pixel electrode 1
A difference in thermal expansion occurs between 0 and 0. Therefore, distortion occurs at the interface between the conductive transparent film 13 and the reflective pixel electrode 10,
Only the upper conductive conductive film 13 having a small linear expansion coefficient is selectively removed.

Furthermore, since the conductive transparent film 13 is irradiated with the laser beam LB having an energy density lower than that required for processing the conductive reflective film 11, the lower layer of the conductive transparent film 13 to be removed. The reflection pixel electrode 10 in the above is not removed by the irradiation of the laser beam LB.

As described above, according to this embodiment, when the conductive transmissive film 13 is processed by the laser beam LB to form the transmissive pixel electrode 12, the lower reflective pixel electrode 1 is formed.
Since it is not removed to 0, the reflective pixel electrode 10
It is possible to pattern both the transparent pixel electrode 12 and the transparent pixel electrode 12 by laser processing. As a result, photolithography is not required to form the reflective pixel electrode 10 and the transmissive pixel electrode 12, and the number of steps can be significantly reduced. Further, since the liquid crystal display device according to the present embodiment has a structure in which the transmissive pixel electrode 12 is formed on the reflective pixel electrode 10, the reflective pixel electrode 10 and the transmissive pixel electrode 12 can be patterned by laser processing. It will be possible. Further, in the liquid crystal display device according to the present embodiment, since the transmissive pixel electrode 12 covers only the opening 10w of the reflective pixel electrode 10 and its peripheral portion, the transmissive pixel electrode 12 is formed.
Does not interfere with the reflection of light from the reflective pixel electrode 10,
A bright screen is obtained.

The present invention is not limited to the above embodiments. In the above-described embodiment, the patterning of the reflective pixel electrode 10 and the transmissive pixel electrode 12 is performed by laser processing, but the laser processing is used only for patterning one of the reflective pixel electrode 10 and the transmissive pixel electrode 12.
On the other hand, photolithography can be used to reduce the number of steps required for electrode formation. Further, although the TFT element 30 of the liquid crystal display device according to the above-described embodiment has a so-called bottom gate structure, the present invention is also applicable to manufacture of a liquid crystal display device including a top gate structure TFT element.

[0058]

According to the present invention, two pixel electrodes in a reflective / transmissive liquid crystal display device can be formed by a dry process instead of a photolithography process.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a drive substrate in a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a TF of a liquid crystal display device according to an embodiment of the present invention.
3 is a cross-sectional view showing a cross-sectional structure around a T element 30. FIG.

FIG. 3 is a cross-sectional view showing a cross-sectional structure around a transmissive portion 3 of a drive substrate of a liquid crystal display device according to an embodiment of the present invention.

FIG. 4 is a reflection pixel electrode 10 and a transmission pixel electrode 12.
It is a figure which shows an example of a schematic structure of the laser processing apparatus used for the patterning of.

FIG. 5 is a diagram for explaining an electrode forming step, which is a cross-sectional view showing a state in which the conductive reflective film 11 is formed on the flattening layer 56.

FIG. 6 is a diagram for explaining an electrode forming step, which is a cross-sectional view showing a state in which the conductive reflective film 11 is patterned by laser processing.

FIG. 7 is a diagram for explaining an electrode forming step, which is a cross-sectional view showing a state in which a conductive transmissive film 13 is formed on the reflective pixel electrode 10.

8 is a diagram for explaining an electrode forming step, which is a cross-sectional view showing a state in which the conductive transmissive film 13 is patterned by laser processing. FIG.

FIG. 9 is a plan view showing an example of the structure of a drive substrate of a reflective / transmissive liquid crystal display device.

10 is a cross-sectional view showing a cross-sectional structure of the TFT element 104 of the liquid crystal display device, which is a cross-sectional view taken along the line AA in FIG.

11 is a cross-sectional view showing a structure around a transmission part W of the liquid crystal display device, which is a cross-sectional view taken along the line BB in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Driving substrate, 2 ... Pixel electrode part, 5 ... Signal line, 6 ... Gate line, 7 ... Gate electrode, 8 ... Polysilicon layer, 10 ... Reflection pixel electrode, 12 ... Transmission pixel electrode, 30 ... TFT element , 40 ... Substrate, 42 ... Barrier film, 46 ... Gate insulating film, 48, 52 ... Interlayer insulating film, 54 ... Diffusion plate, 56 ... Flattening layer, 60 ... Liquid crystal, 62 ... Counter electrode, 64 ... Color filter, 66 , 70 ... Retardation plate, 68, 72 ... Polarizing plate,
74 ... A surface light source.

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[Procedure amendment]

[Submission date] April 23, 2002 (2002.4.2)
3)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

FIG. 10 shows a TFT element 10 of a liquid crystal display device.
9 is a cross-sectional view showing the cross-sectional structure of FIG.
It is sectional drawing of the A line direction. FIG. 11 is a cross-sectional view showing the structure around the transmissive portion W of the liquid crystal display device, which is a cross-sectional view taken along the line BB in FIG. TF shown in FIG.
In the T element 104, a gate electrode 107 made of a conductive material such as Cr or Mo is formed in a predetermined pattern on an insulating and transparent substrate 110 made of a glass plate or the like. The gate electrode 107 is electrically connected to the above-described gate line 106 and electrically connected to a storage capacitor wiring (not shown).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The transparent pixel electrode 1 is formed on the flattening layer 119.
03 is formed, and the reflection pixel electrode 102 is formed on the transmission pixel electrode 103. Transmission pixel electrode 103
Is formed of a transparent film such as an ITO (Indium Tin Oxide) film, and the reflective pixel electrode 102 is formed of a reflective film of Al , Ag, or the like.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012] The present invention was made in view of the above problems, its object is formable reflective regardless of the pixel electrode in photolithography Gras <br/> Fi chromatography step / transmissive type liquid crystal display device To provide a reflective / transmissive liquid crystal display device.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a configuration of a drive substrate in a liquid crystal display device according to an embodiment of the present invention. As shown in FIG. 1, a driving substrate 1 includes pixel electrode portions 2 arranged in a matrix and TFT (Thin Film Transistor) elements 3 provided for each pixel electrode portion 2.
Has 0 and. A signal line 5 and a gate line 6 are provided between the pixel electrode portions 2.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

The substrate 40 is formed of a material that transmits light, such as a glass material. The gate electrode 7 is patterned on the substrate 40 together with the gate line 6 described above. The gate electrode 7 is formed of, for example, Cr (black).
It is obtained by depositing a conductive material such as aluminum on the substrate 40 by sputtering and patterning the Cr thin film by, for example, photolithography.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

The reflective pixel electrode 10 is patterned on the flattening layer 56. The reflective pixel electrode 10 is
For example, it is formed of a conductive reflective film of Al , Ag or the like. As will be described later, in the reflective pixel electrode 10, after a conductive reflective film is sputtered on the flattening layer 56,
Patterning is performed by ablation by laser light and thermal processing described later.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

The laser light source 201 outputs a laser beam LB. By the laser beam LB output from the laser light source 201, the processing surface 210 of the processing object 210 is processed.
f is processed. As the laser light source 1, for example, an excimer laser or a YAG laser is used. There are a plurality of types of excimer lasers having different laser media. As the laser medium, XeF (351
nm), XeCl (308 nm), KrF (248n)
m), ArF (193 nm) and F ₂ (157 nm). The excimer laser is greatly different from the YAG laser (1.06 μm) and the CO ₂ laser (10.6 μm) that perform processing using thermal energy in that the oscillation wavelength is in the ultraviolet range. The excimer laser essentially oscillates only in pulses, has a pulse width of several nanoseconds to several tens of nanoseconds , and has a rectangular laser beam shape. In general, also
Since the excimer laser performs a process called photoablation that is not susceptible to thermal effects that photochemically dissociate the bond directly, the edge of the surface to be processed is extremely sharp. On the other hand, in the YAG laser and the CO ₂ laser, the processed portion is melted and then evaporated, so that the peripheral portion is rounded by the influence of heat and the end face is not clean. Further, the excimer laser has an initial beam cross section of about 10 × 10 mm, and a relatively large area is collectively formed by increasing the area and the area of this laser beam by a beam shaper described later. Can be processed. Therefore, the excimer laser is suitable for simultaneously processing a large area.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

Next, patterning of the reflective pixel electrode 10 and the transmissive pixel electrode 12 using the laser processing apparatus 200 will be described. In FIG. 5, in the transparent portion 3 of the drive substrate 1, a hole H is formed in the barrier film 42, the gate insulating film 46, the interlayer insulating films 48 and 52, the diffusion plate 54, and the flattening layer 56, which are stacked on the substrate 40, by etching. After the formation, the conductive reflection film 11 is formed on the flattening layer 56. The conductive reflection film 11 is, for example, A
l, is formed by sputtering a metal material such as A g.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0058

[Correction method] Change

[Correction content]

[0058]

According to the present invention, it becomes possible formed by a dry process regardless the two pixel electrodes in the reflective / transmissive type liquid crystal display device of the photolithography over <br/> process.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hidetoshi Murase             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Kosei Aso             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Kiyomi Kiyomi             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F term (reference) 2H091 FA14Y FA41Z FC14 FD04                       FD06 GA02 GA13 LA12 LA16                 2H092 GA13 GA17 HA04 HA05 JA24                       JB05 JB07 KA04 MA12 MA19                       NA25 NA27 PA12 PA13

Claims (10)

[Claims] 1. A reflective pixel electrode having a light-transmitting substrate, a conductive reflective film patterned in a predetermined shape on the substrate, and an opening through which light passes, and a conductive film patterned in a predetermined shape. A permeable membrane,
A transmissive pixel electrode that is in contact with the reflective pixel electrode and covers at least the opening; a counter electrode that is disposed to oppose the reflective pixel electrode and the transmissive pixel electrode; and the reflective pixel electrode and the transmissive pixel electrode. Liquid crystal display device having a liquid crystal interposed between the counter pixel electrode and the counter electrode. 2. The conductive transmissive film is made of a material in which the energy density of laser light required for selective removal by processing with laser light is smaller than that of the conductive reflective film. Liquid crystal display device. 3. The liquid crystal display device according to claim 2, wherein the conductive transmissive film is made of a material having a linear expansion coefficient smaller than that of the conductive reflective film. 4. The liquid crystal display device according to claim 1, wherein the transmissive pixel electrode covers only the opening of the reflective pixel electrode and a peripheral portion of the opening. 5. The liquid crystal display device according to claim 1, further comprising a planar light source disposed on the non-formation surface side of the reflective pixel electrode and the transmissive pixel electrode of the substrate. 6. A method of manufacturing a liquid crystal display device, comprising: a transparent pixel electrode, which is patterned into a predetermined shape, and which transmits light, and a reflective pixel electrode which has an opening for transmitting light and which reflects light, on a transparent substrate. A method for manufacturing a liquid crystal display device, wherein at least one of the patterning of the transmissive pixel electrode and the reflective pixel electrode is performed by processing using a laser beam. 7. A step of forming a conductive reflective film on a substrate which transmits light, and a reflective reflection film having an opening through which the conductive reflective film is patterned into a predetermined shape by processing using laser light. Forming a pixel electrode, forming a conductive transparent film on the substrate so as to cover the reflective pixel electrode, and patterning the conductive transparent film into a predetermined shape by processing using a laser beam. 7. The method for manufacturing a liquid crystal display device according to claim 6, further comprising: forming a transmissive pixel electrode that covers at least the opening. 8. The material according to claim 7, wherein the conductive transparent film is made of a material having an energy density of laser light required to be selectively removed by processing using laser light is smaller than that of the conductive reflective film. Manufacturing method of the liquid crystal display device of. 9. The method for manufacturing a liquid crystal display device according to claim 8, wherein a material having a linear expansion coefficient smaller than that of the conductive reflective film is used for the conductive transparent film. 10. The step of forming the transmissive pixel electrode comprises:
8. The liquid crystal display device according to claim 7, wherein a portion of the conductive transmissive film other than a region covering the opening of the reflective pixel electrode and a peripheral portion of the opening is selectively removed.