JP3215618B2 - Method for manufacturing reflective liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a method of manufacturing a reflection type liquid crystal display device which performs display by reflecting incident light.

[0002]

2. Description of the Related Art In recent years, applications of liquid crystal display devices to word processors, laptop personal computers, pocket televisions, and the like have been rapidly advancing. In particular, among the liquid crystal display devices, a reflection type liquid crystal display device that performs display by reflecting light incident from the outside does not require a backlight, and thus consumes low power, is thin, and can be reduced in weight. Have been.

Conventionally, a reflection type liquid crystal display device has a TN
(Twisted nematic) method and STN (super twisted nematic) method are used. However, in these methods, a half of the light intensity of natural light is inevitably used for display by a polarizing plate. There is a problem of darkening.

To solve such a problem, there has been proposed a display mode in which all light beams of natural light are effectively used without using a polarizing plate. An example of such a display mode is a phase transition type guest-host system (DL White and GN Taylor).
r: J. Appl. Phys. Vol. 45 pp. 4
718, 1974, hereinafter referred to as Document White). In this display mode, a cholesteric-nematic phase transition phenomenon caused by an electric field is used. A reflection type multi-color display in which a micro color filter is further combined with the phase change type guest-host type has been proposed (for example, Tohru Koizumiand).
Tatsuo Uchida. Proceedings
of theSID. VoL. 29/2, pp. Fifteen
7.1988).

In order to obtain a brighter display in a display mode that does not require such a polarizing plate, it is necessary to increase the intensity of light scattered in a direction perpendicular to the display screen with respect to incident light from all angles. is there. For that purpose, it is necessary to create a reflector having optimal reflection characteristics.
In the above-mentioned document White, the surface of a substrate made of glass or the like is roughened with an abrasive, and the surface roughness is controlled by changing the etching time with hydrofluoric acid, and a silver thin film is formed on the surface. Is described.

[0006] However, in this method, since the glass substrate is scratched using an abrasive to form the irregularities, it is difficult to form uniform irregularities. Another problem is that the reproducibility of the uneven shape is poor.

FIG. 11A shows a matrix substrate 2 having a thin film transistor (hereinafter, referred to as a TFT) 1 as a switching element used in an active matrix system.
11 (b) is a cross-sectional view of the matrix substrate 2 shown in FIG. 11 (a) as viewed from a cutting plane line VV. In the matrix substrate 2, a plurality of gate bus lines 3 made of chromium, tantalum, or the like are provided in parallel with each other on an insulating substrate 2a made of glass or the like, and a gate electrode 4 is branched from the gate bus line 3 and provided. Have been.
The gate bus wiring 3 functions as a scanning line.

[0008] As shown in FIG.
Covering the entire surface of the substrate 2a with silicon nitride (SiN
x), a gate insulating film 5 made of silicon oxide (SiOx) or the like is formed. On the gate insulating film 5 above the gate electrode 4, a semiconductor layer 6 made of amorphous silicon (hereinafter referred to as a-Si), polycrystalline silicon, CdSe, or the like is formed. A-S is provided at both ends of the semiconductor layer 6.
An n ⁺ or p ⁺ contact layer 11 made of i, polycrystalline silicon, CdSe, or the like is formed. As shown in FIG. 12, the gate insulating film 5 formed on the entire surface of the substrate 2a has a portion of the gate bus line 3 above the input terminal 3a removed.

As shown in FIG. 11B, a source electrode 7 made of titanium, molybdenum, aluminum or the like is formed on one end of the semiconductor layer 6 so as to overlap. A drain electrode 8 made of titanium, molybdenum, aluminum or the like is formed on the other end of the semiconductor 6 in the same manner as the source electrode 7. An end of the drain electrode 8 opposite to the semiconductor layer 6 is provided with ITO (Indium Tin Oxid).
The pixel electrode 9 made of a transparent conductive film as shown in FIG.

[0010] As shown in FIGS. 11 (a) and (b), the source electrode 7, source bus lines 10 intersecting across the gate insulating film 5 above the gate bus line 3 are connected. The source bus wiring 10 functions as a signal line. The source bus wiring 10 is also formed of the same metal as the source electrode 7. The gate electrode 4, gate insulating film 5, semiconductor layer 6, source electrode 7, and drain electrode 8 are TFT
1 and the TFT 1 thus configured has the function of a switching element.

When the matrix substrate 2 having the TFT 1 having the structure shown in FIGS. 11A and 11B and FIG. 12 is applied to a reflection type liquid crystal display device, the pixel electrode 9 is made of a light reflection material such as aluminum or silver. It is necessary to form unevenness on the gate insulating film 5 in addition to the metal having the property.
Generally, it is not preferable to form irregularities on the gate insulating film 5 because it affects a process of forming an element.
Further, it is difficult to uniformly form the tapered unevenness on the insulating film 5 made of an inorganic material.

In JP-A-56-94386,
Satoru Yazawa et al. Disclosed a method of increasing the intensity of light scattered in a direction perpendicular to the display screen by using a metal thin film layer having an uneven surface as a reflector of a liquid crystal display device. The method of manufacturing the metal thin film layer shown in (3) is described.

(1) A method in which a metal thin film layer is formed on a substrate by using a vapor deposition method or a sputtering method under a certain condition to obtain a metal thin film having an uneven surface.

(2) A method in which a metal thin film layer formed on a substrate by a vapor deposition method or a sputtering method is subjected to heat treatment and recrystallized to obtain a metal thin film layer having an uneven shape on the surface. For example, when aluminum or an aluminum alloy is used as the material of the metal thin film layer, since the melting point of these materials is 660 ° C., recrystallization is performed in a heating range of 100 ° C. to 600 ° C. Due to this recrystallization, rearrangement of atoms occurs in the metal thin film, and as a result, a metal thin film layer having an uneven shape can be obtained.

(3) As shown in FIG. 13, an alloy thin film layer 63 formed on a substrate by a vapor deposition method or a sputtering method is subjected to a heat treatment, so that a deposit 64 is deposited.
A method of removing the vicinity of the surface of the alloy thin film layer 63 by etching.
For example, an alloy thin film layer 63 containing 2% by weight of silicon in aluminum is deposited in an N ₂ atmosphere at 400 ° C. for 20 minutes.
After heating for a minute, an intermetallic compound of aluminum and silicon having a particle size of about 0.2 to 1.0 μm is deposited as a precipitate 64. For example, the alloy thin film layer 6 having a thickness of 1.0 μm
After depositing No. 4 and removing 0.2 μm of the surface layer by etching, this surface has a white color.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 56-94386 (hereinafter referred to as document Yazawa 1) states that the surface of the metal thin film layer may be treated by a sand blast method. Furthermore, since the irregularities and steps on the surface of the metal thin film layer have a slightly adverse effect on the formation of the alignment treatment film for the liquid crystal, the surface of the liquid crystal drive electrode (pixel electrode) is made of silicon resin, epoxy resin, polyimide resin or the like. It is stated that the effect of the alignment treatment can be increased by forming a transparent thin film such as an organic thin film or an inorganic resin and flattening the surface.

However, the method of forming a reflector disclosed in the above-mentioned document Yazawa largely depends on chance, and the surface of a substrate made of glass or the like described in the above-mentioned document White is coated with an abrasive. It is possible to control the surface irregularities by changing the time of roughening and etching with hydrofluoric acid, and to form uniformly the tapered irregularities like the reflector that forms the silver thin film on the irregularities. Have difficulty.

The fact that the reflector has a white color means that
This means that the light from the reflection plate is dispersed and scattered in all directions. When the reflector also serves as the liquid crystal drive electrode of the liquid crystal display device and is formed on the surface of the substrate that is in contact with the liquid crystal, light from the reflector passes through the liquid crystal layer and the opposite substrate and exits to the atmosphere. Assuming that the refractive index of the liquid crystal layer and the substrate is 1.5 and the refractive index of the air is 1, when the scattered light from the reflector is inclined horizontally about 48 ° or more with respect to the interface between the atmosphere and the substrate, The scattered light is reflected at the interface and cannot exit the liquid crystal display device. Therefore, when such a reflection plate is used, the range of scattered light that can be used as display light is limited, and the display screen becomes dark. Therefore, in order to obtain a brighter display screen, it is necessary that the reflector has directivity and the scattering angle of the reflected light can be controlled.

However, the above-mentioned documents Yazawa and W
It is very difficult to control the reflected light from the reflector by the method described in "hit" because of the large contingency in the formation of the reflector, and the reproducibility is poor. Also, Satoru Yazawa et al., In Japanese Patent Application Laid-Open No. 56-156864 (hereinafter referred to as Document Yazawa 2), with regard to the reflection characteristics of a reflector formed by heating aluminum or an aluminum alloy, aluminum is heated at 400 ° C. to 450 ° C. It is stated that the entire display panel looks dark even when a reflector formed by heat treatment in an inert atmosphere or a hydrogen atmosphere is used because the ratio of mirror surfaces is large. Therefore, in order to obtain a further degree of scattering, it is necessary to perform a heat treatment at a higher temperature, but such a heat treatment is not preferable because it destroys a TFT element or a MIM element used as a switching element. (For example, in the case of an a-Si TFT, hydrogen in the semiconductor layer is released at 350 ° C. or higher).

In order to be able to use the liquid crystal display device of the active matrix type using an a-Si TFT element or an MIM element as a switching element, a reflecting plate having directivity for controlling a scattering angle of reflected light is formed at a low temperature. The forming method is disclosed in the above-mentioned document Yazawa 2. According to this method, first, SiO ₂ is formed in a triangular wave shape on the substrate surface by the CVD method, and aluminum is vapor-deposited thereon, thereby forming the reflection plate 65 as shown in FIG. The reflection plate 65 has a cross section close to a sine wave shape, and has an average inclination angle θ = 5 ° to 30 °.

Also, Satoru Yazawa et al., JP-A-56-15686.
In Japanese Patent Publication No. 5 (hereinafter referred to as Document Yazawa 3), a reflection plate obtained by heat-treating aluminum or an aluminum alloy or thereafter further performing etching treatment has poor display characteristics when used in a liquid crystal display device. In the above-mentioned document Yazawa 3, it is described that a reflection plate 66 having irregularities as shown in FIG. 15 is formed by vapor-depositing aluminum after taper-etching SiO ₂ formed by a CVD method into a triangular wave shape. Has been disclosed.

As a method for forming a reflector by forming a metal thin film on an insulating resin layer having irregularities, there is the following method.

Komatsubara et al., US Pat. 4,51
9,678 (hereinafter referred to as Komatsubara),
The following method is disclosed. First, a polymer-based or polyimide-based resin is applied on a substrate on which an element is formed, and thermally cured to form a resin layer. A resist pattern is formed thereon by a photolithography process, and wet etching or dry etching (RIE or the like) is performed using the resist pattern as a mask to form a depression in the resin layer. After removing the resist, the resin layer is heated at 150 ° C. to 500 ° C., so that the edge of the depression is made gentle. Thus, in the resin layer,
After forming a gentle unevenness in the cross section and forming a contact hole by a photolithography process, an aluminum film is vacuum-deposited on the resin layer to form a reflector.

In Komatsubara literature, as another method, after forming a large number of columnar projections on a substrate, a resin layer is applied thereon and cured to form unevenness having a gentle cross section. Having a resin layer. On this resin layer, a reflector made of aluminum, silver, or an alloy thereof is formed. The above-mentioned cylindrical convex portion is
A single layer or a plurality of layers made of an insulator, a semiconductor, or a metal are formed over a substrate, and the layers are selectively etched using a mask pattern (resist). In any case, the metal thin film formed on the resin layer is in electrical contact with an electrode on the substrate via a contact hole formed in the resin layer.

In JP-A-6-75238, Hisaka Nakamura et al. Applied a photosensitive resin on a substrate, and exposed and developed the photosensitive resin through a light-shielding means in which circular light-shielding regions were arranged. After that, heat treatment is performed to form a plurality of convex portions. An insulating film is formed on the plurality of protrusions along the shape of the protrusions, and a reflector made of a metal thin film is formed on the insulating film.

As described above, the reflector is formed by operating an insulating film far from the element (close to the interface with the liquid crystal) to obtain a desired uneven shape so as not to affect the element formed on the substrate. Preferably, it is formed. Also, rather than roughening the surface of the metal thin film itself (heat treatment, etching, etc.) used as a reflector, an insulating layer having an uneven shape is formed under the metal thin film, and the mirror-finished metal is formed along the uneven shape. It is preferably obtained by forming a thin film. Furthermore, since it is difficult to form unevenness having a gentle cross section uniformly on the insulating layer made of an inorganic material, it is preferable to form the insulating layer using a resin whose unevenness can be easily controlled.

[0027]

As described above, when a resin layer is used to form a reflector having desirable reflection characteristics (directivity), a reflector (reflection electrode) formed on the resin layer is used. ) To connect to an element (such as a switching element) formed under the resin layer
It is necessary that form the. The reflection electrode is connected to a routing electrode extending from an element formed on the substrate via a contact hole. Here, the routing electrode is an electrode for applying a voltage for display to each reflective electrode.

In the case of using a non-photosensitive resin, the contact hole is formed by a photolithography process after thermosetting the resin layer, and in the case of using a photosensitive resin, the contact hole is formed by exposing and developing the resin layer. Is done. It is advantageous to use a photosensitive resin because the number of steps is small.

When a resin layer is formed using a photosensitive resin, the resin layer is thinned by the development even in a portion selectively left by exposure and development. Therefore,
The development time greatly affects the formation of the uneven portion having a gentle cross section of the resin layer.

The longer the developing time, the better the conductivity of the contact hole.

The developing speed of the resin layer in the substrate is higher at the peripheral portion of the substrate than at the central portion. Therefore, for example, when forming a reflector using a large substrate of 300 × 300 mm or more, if development is performed for a sufficient time to obtain good conduction of the contact hole in the center of the substrate, excessive development occurs in the peripheral portion of the substrate. And the reflector approaches a mirror surface state. Therefore, the display of the liquid crystal display device using the reflector formed at the peripheral portion of the substrate becomes dark.

When a contact hole is formed by non-photosensitive resin as described in the above-mentioned document Komatsubara, for example, by dry etching such as RIE, the plasma in the dry etching has a high density at the center of the substrate. The etching proceeds from the center of the substrate. Since both the resist and the resin used as the mask pattern are organic films, it is difficult to make the selectivity greater than 10. Therefore, if etching is continued so that sufficient conduction of the contact hole can be obtained in the peripheral portion of the substrate,
At the center of the substrate, the regression of the resist is large, causing the contact holes to become large and the resin film to decrease. Therefore, table <br/> shows a liquid crystal display device using a reflection plate formed of a substrate center portion becomes dark.

The thickness of a liquid crystal layer in a liquid crystal display device or the distance between a pair of substrates before injecting liquid crystal (hereinafter referred to as a cell distance) is important in affecting the response speed and contrast of the liquid crystal display device. Parameters. Therefore, measuring the thickness of the liquid crystal layer and the cell interval is important for production control of the liquid crystal display device.

Conventionally, in the case of a transmission type liquid crystal display device or a reflection type liquid crystal display device in which a reflection plate is formed outside a pair of substrates, when the liquid crystal cell is in a transmission type, the alignment film of one of the substrates is removed. The cell spacing was measured by using interference between light reflected by an interface between a liquid crystal layer or an air layer and light reflected by an interface between the liquid crystal layer or an air layer and an alignment film of the other substrate. However, in a reflection type liquid crystal display device in which a reflection plate is formed as a pixel electrode between a pair of substrates, the intensity of the scattered reflected light from the reflection electrode is too strong, so that the wavelength of the interference light may be measured. It is difficult, and the conventional measurement method using optical interference cannot be used.

On the other hand, there is a method of measuring a cell interval using a laser beam. This method, as shown schematically in FIG.
A first lens 17a for collimating the laser light from the semiconductor laser 19 into parallel light, and a second lens 17 for condensing the laser light reflected by the sample 18 to be measured
The optical system provided with b is used. Utilizing the fact that the reflected light fed back has a peak when the focal point of the second lens 17b coincides with the reflection surface of the sample 18 (for example, the interface between the alignment film and the liquid crystal layer and the surface of the reflection electrode). I have. 2
From the position (moved distance) of the second lens 17b at the peak of one reflected light, the distance between the two reflecting surfaces can be obtained.

FIG. 17 shows the result of measuring the surface of a reflective electrode having irregularities formed in order to obtain scattered light using this method. As can be seen from FIG. 17, the peak of the reflected light cannot be obtained because the laser light is scattered on the reflective electrode surface having the uneven shape. Therefore, the position of the reflector cannot be measured by the measurement using the laser beam, and the cell interval cannot be measured.

The present invention has been made in view of the above circumstances, and its purpose is to firstly provide a 300 × 3
Even when a reflector of a liquid crystal display device is formed using a large substrate of 00 mm or more, the reflection characteristics of the reflector are good (for example, 100 or more) over the entire substrate, and a contact hole with good conduction is formed. A method of manufacturing a liquid crystal display device, and a variation in a reflection characteristic of a reflection plate formed between a central portion and a peripheral portion of a substrate is suppressed within an allowable range of about 10%, and a conductive state is maintained over the entire substrate. provides a method of manufacturing a liquid crystal display device good contact hole is formed, the second, to provide a method of manufacturing a reflection type liquid crystal display device that enables stable measurement of the thickness or the substrate spacing in the liquid crystal layer is there.

[0038]

According to the present invention , there is provided a method of manufacturing a reflection type liquid crystal display device , comprising the steps of:
A substrate, a second substrate having a light-transmitting electrode,
A liquid crystal layer disposed between the first and second substrates.
This is a method for manufacturing a projection-type liquid crystal display device. The method is insulating
A switch for supplying a voltage signal for display to the reflective electrode on the substrate.
Forming an switching element;
A routing electrode connected to the element and extending below the reflective electrode;
Thus, at least one region has two or more different types
Forming a routing electrode on which metal is laminated
And an insulating tree on the switching element and the routing electrode.
Forming a grease layer and the two types of the routing electrodes
The insulating resin layer on the region where the different metals are stacked
Forming a contact hole;
Etching using the metal etchant on the top layer of the electrode
Of the uppermost layer at the bottom of the contact hole.
Remove the metal layer until it reaches some or the underlying metal layer
By removing, the insulation with the uppermost metal layer
Removing the resin residue;
To cover each pixel on the insulating resin layer so as to cover
Forming an electrode, the insulating resin layer
The step of forming is performed in a region where the reflective electrode is formed.
And the region where the contact hole is formed is
A circular convex pattern made of insulating resin is
Forming and the same on the circular convex pattern
Step of applying insulating resin to form second insulating resin layer
And a step for forming the contact hole.
The contact hole is formed in the second insulating tree.
Formed on the oily layer, in the step of forming the reflective electrode.
And the reflective electrode formed on the insulating resin layer is scattered.
Having a reflective property at the bottom of the contact hole.
The pole is formed in a mirror state, and is located at the bottom of the contact hole.
The light reflected by the reflective electrode in a mirrored state
By using this, a step for measuring the thickness of the liquid crystal layer is performed.
To achieve the above object.

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

According to the method of manufacturing a reflection type liquid crystal display device according to the present invention, a first substrate having a plurality of reflective electrodes, a second substrate having a translucent electrode, and the first and second substrates are provided. And a liquid crystal layer disposed therebetween. The method comprises the steps of: forming, on an insulating substrate, a switching element that supplies a voltage signal for display to the reflective electrode; and a routing electrode connected to the switching element and extending below the reflective electrode, the method comprising: Forming a routing electrode in which two or more different metals are stacked in the region of the portion; forming an insulating resin layer on the switching element and the routing electrode; and determining the two or more different types of the routing electrode. Forming a contact hole in the insulating resin layer on the region where the metal is laminated, and performing etching using an etchant for a metal in the uppermost layer of the routing electrode; Removing the layer until it reaches a portion or a metal layer therebelow, thereby forming the insulating resin together with the uppermost metal layer. Removing the residues, so as to cover the contact holes, comprising the steps of: in response to each pixel on the insulating resin layer to form a reflective electrode, used in the step of etching d
The etching solution is hydrofluoric acid with a concentration of 0.25% to 1.00%.
A liquid mixture containing the reflection electrode.
The reflection electrode formed on the insulating resin layer is dispersed.
Having a disorder, and the reflection at the bottom of the contact hole.
The electrode is formed in a mirror state, and the bottom of the contact hole is formed.
Reflected by the reflective electrode in a mirror state at
Is used to measure the thickness of the liquid crystal layer.
And thereby achieve the above object.

In the step of forming the contact hole, preferably, the contact hole is formed so that the opening area is 400 μm ² or more and 8% or less of the area of the reflection electrode.

In one embodiment, the switching element is a thin film transistor, the lower metal layer of the routing electrode is formed of the same material as the gate electrode of the thin film transistor, and the upper metal layer of the routing electrode is It is formed from the same material as the source electrode of the thin film transistor.

In the step of forming the routing electrode, the lower metal layer is formed of a material selected from the group consisting of tantalum, tantalum containing 50 atomic% or less of nitrogen, and tantalum containing molybdenum. The layer may be titanium.

In another embodiment, the switching element is a metal-insulating-layer (MIM) element, and a lower metal layer of the routing electrode is formed of the same material as a first electrode of the MIM element; The upper metal layer of the routing electrode is formed of the same material as the second electrode of the MIM element.

In the step of forming the routing electrode, the lower metal layer may be made of tantalum, tantalum containing 50 atomic% or less of nitrogen, 10 atomic% or less of tantalum containing silicon and tungsten, and 10 atomic% or less of The upper metal layer may be formed of a material selected from the group consisting of tantalum containing at least one element each having a valence of less than or equal to six or more, and the upper metal layer may be titanium.

[0051]

[0052]

[0053]

[0054]

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

(Embodiment 1) FIG. 1 shows a cross section of a part of a reflection type liquid crystal display device 30 according to one embodiment of the present invention. The liquid crystal display device 30 includes a lower substrate (active matrix substrate) 30a on which switching elements (TFTs) are formed, an upper substrate (opposite substrate) 30b, and a liquid crystal layer 49 sandwiched between the two substrates. FIG.
FIG. 2 is a plan view of a lower substrate 30a shown in FIG.

First, the configuration of the lower substrate 30a will be described. As shown in FIGS. 1 and 2, an insulating substrate 3 made of glass or the like is used.
A plurality of gate bus lines 32 made of chromium, tantalum, or the like are provided in parallel with each other, and a gate electrode 33 is branched from the gate bus line 32.
In addition, as the material of the gate bus wiring 32 and the gate electrode 33, tantalum containing 50 atomic% or less of nitrogen or tantalum containing molybdenum may be used. The gate bus wiring 32 functions as a scanning line.

As shown in FIG. 2, the gate bus wiring 3
2, a gate insulating film 34 made of silicon nitride (SiNx), silicon oxide (SiOx), or the like is formed on the entire surface of the substrate 31. Above the gate electrode 33, via a gate insulating film 34, amorphous silicon (hereinafter a-Si), polycrystalline silicon, CdSe
A semiconductor layer 35 is formed. At both ends of the semiconductor layer 35, a-Si, polycrystalline silicon, CdS
An n ⁺ or p ⁺ contact layer 41 made of e or the like is formed.

A source electrode 36 made of titanium, molybdenum, aluminum or the like is formed on one end of the semiconductor layer 35 on which the contact layer 41 is overlapped. The semiconductor layer 3 on which the contact layer 41 is superimposed
5, at the other end, titanium as in the case of the source electrode 36,
Drain electrode 3 made of molybdenum, aluminum, etc.
7 and the routing electrode 37a are formed in an overlapping manner. The drain electrode 37 and the routing electrode 37a may be formed integrally. The other end of the routing electrode 37 a overlaps a pad 50 formed on the substrate 31. The pad 50 is a lower metal layer of the routing electrode 37 a in the contact hole 43, and has at least a larger area than the contact hole 43. In this embodiment, the pad 50 is formed of the same material as the gate electrode 33.

The gate insulating film 34 is made of a conventional example (FIG. 1).
As described in 2), the portion on the input terminal of the gate bus line 32 is removed. In this step, FIG.
As shown in FIG. 7, the gate insulating film 34 on the pad 50 is also removed at the same time.

The gate electrode 33, the semiconductor layer 35, the source electrode 36, and the drain electrode 37 form an a-Si TFT as the switching element 40.

An organic insulating film 42 is formed on the entire surface of the substrate 31 on which the switching elements are formed. A contact hole 43 is formed in the part of the routing electrode 37 a of the organic insulating film 42. In the region of the organic insulating film 42 where the reflective electrode (pixel electrode) 38 is formed, a convex portion 42a having a tapered shape and a circular cross section at the tip is formed at a height H. The height H is preferably about 10 μm or less in order to reduce a method of forming the organic insulating film 42 described later, a problem in a process of forming the contact hole 43, and a variation in cell thickness when the liquid crystal display device 30 is formed. preferable.

On the organic insulating film 42, a circular projection 42a is formed.
A reflective electrode 38 made of aluminum is formed so as to cover the region in which is formed and the contact hole 43. The reflection electrode 38 is connected to the routing electrode 37a in the contact hole 43 via the pad 50.

Next, a method for manufacturing a reflection type liquid crystal display device 30 will be described with reference to the drawings about the formation method of the active matrix substrate 30a.

First, an insulating substrate 31 made of glass or the like is used.
On top of this, elements such as the switching element 40 are formed by an ordinary method. In the present embodiment, as the substrate 31,
For example, a 1.1 mm thick glass substrate having a trade name of 7059 manufactured by Corning Incorporated is used. When forming the switching element 40, a pad 50 which is a metal layer having at least a larger area than the contact hole is formed in a portion where the contact hole 43 is to be formed. Further, a routing electrode 37a is laminated thereon.

[0066] pads 50 becomes a lower metal layer in the contact hole portion, in this embodiment, the same material as the gate bus lines 32 of the TFT, preferably are formed have <br/> use the tantalum. As a result, the gate bus wiring 3
2. The gate electrode 33 and the pad 50 can be formed by patterning at the same time. In addition, the routing electrode 3
7a is an upper metal layer in the contact hole portion, and is made of the same material as the source electrode 36 and the drain electrode 37 of the TFT, preferably titanium. Source electrode 36, drain electrode 37, and routing electrode 37a
May be simultaneously patterned. In this way, as shown in FIG. 4A, at the portion where the contact hole is formed, at least two layers made of different metals are stacked.

The substrate 31 on which each element is formed as described above
Then, as shown in FIG. 3A, a photosensitive resin is applied by spin coating to form an organic insulating resin layer 12. In FIGS. 3A to 3F, description of each element is omitted. The organic insulating film 12 is formed of an acrylic photosensitive resin by a spin coating method, preferably at a speed of 500 rpm to 3000 rpm.
In the present embodiment, the coating is performed so that the thickness of the organic insulating layer 12 is about 2.5 μm by rotating at 1300 rpm for 30 seconds.

Next, the glass substrate 31 on which the organic insulating layer 12 is formed is pre-baked at, for example, 90 ° C. for 30 seconds.
Subsequently, as shown in FIG. 3B, the photomask 13 is disposed above the organic insulating layer 12, and light is irradiated from above the photomask 13 as shown by an arrow in FIG. ). Photomask 13, for example, as shown in FIG. 6, it is possible to use a photomask 13 2 different sizes of the circular pattern holes 13a and 13b are formed in the plate member 13c. In the photomask 13 of this embodiment, a pattern hole 13a having a diameter of 5 μm and a diameter of 3 μm are formed.
The m pattern holes 13b are randomly arranged, and the interval between the mutually adjacent pattern holes is at least 2 μm. However, if the pattern holes are too far apart, the upper surface of the organic insulating film 15 formed on the organic insulating layer 12 is unlikely to have a continuous wavy shape, so the pattern hole interval needs to be set appropriately. Also, in order to make the metal layer (reflective electrode 38) formed at the bottom of the contact hole into a mirror surface state,
A photomask 1 is provided on the portion corresponding to the contact hole.
No circular pattern holes are placed in 3.

Next, the organic insulating layer 12 is developed using, for example, a developer having a TMDH concentration of 2.38% manufactured by Tokyo Ohka Co., Ltd. As a result, as shown in FIG.
A large number of fine projections 14a 'and 14b' having different heights are formed on the surface of the substrate 1 corresponding to the pattern holes 13a and 13b. In the state as developed, the protrusions 14a '
And 14b 'are angular at the upper end. In this embodiment,
2.48 μm height due to the pattern holes 13 a having a diameter of 5 μm
m is formed, and the pattern hole 1 having a diameter of 3 μm is formed.
3b formed a convex portion 14b having a height of 1.64 μm.

Next, the substrate 31 on which the projections 14a 'and 14b' are formed is heated at about 200 ° C. for about 60 seconds to perform a heat treatment. Thereby, the corners of the upper ends of the protrusions 14a 'and 14b' are softened and rounded to form the protrusions 14a and 14b having a substantially circular cross section at the upper end as shown in FIG. 3D. .

Next, as shown in FIG. 3 (e), on a substrate 31 which is heat treated, the same photosensitive resin as the organic insulating layer 12 is applied by spin-coating how to form the organic insulating film 15 . Preferably, from 1000 rpm to 3000 r
Spin coat at pm. In this embodiment, 2000 rpm
After spinning at m for 30 seconds, spin coating was performed.

Next, the substrate 3 on which the organic insulating film 15 is formed
1 is pre-baked at 90 ° C. for 30 seconds, for example. continue,
As shown in FIG. 3F, a photomask 16 is disposed above the organic insulating film 15, and light is irradiated from above the photomask 16 to perform exposure. For example, as shown in FIG. 5 , a photomask 16 in which a pattern of contact holes 16a is formed in a plate 16c is used. A contact hole 43 is formed in the organic insulating film 15 in the same manner as in the step of forming the protrusions 14a 'and 14b'.

Next, the substrate 31 having the contact hole 43 formed thereon is heated at 200 ° C. for 60 seconds to form
a 'and 14b' are softened to form a convex portion 14a having a rounded upper end.
And 14b are formed in the same manner as in the process of forming the contact holes 43.

By the above processing, the organic insulating film 42 composed of the convex portions 14a and 14b formed from the organic insulating layer 12 and the organic insulating film 15 formed on these convex portions is formed.

Next, the substrate 31 is immersed in an etchant for etching the uppermost layer of the at least two metal layers stacked in the contact hole. In this embodiment, when the uppermost layer (routing electrode 37a) was formed of titanium, it was immersed in a liquid mixture of hydrofluoric acid and nitric acid at a ratio of 1: 100 to 1: 400 at 25 ° C. for 30 seconds. In the step of etching the upper metal layer of the contact hole, the development residue of the organic insulating film 15 in the contact hole is lifted off by the permeation of the etchant.

Here, for comparison, FIG. 18 shows the development time dependence of the reflection characteristics of the reflector and the contact resistance when the lift-off process was not performed, and the opening area was 900 μm.
^The case where the ^second contact hole is formed will be described. Here, the reflection characteristic of the reflector is 3 with respect to the normal of the reflector.
This is the brightness when the light incident at 0 ° is received on the normal line, and the brightness of the MgO film is shown as 100. Further, the development time is shown as a relative time with the development time at which the best reflection characteristic is obtained as one. If the development time is too short or too long, good reflection characteristics (for example, brightness 1
00 or more) cannot be obtained. As can be seen from FIG. 18, when the lift-off process is not performed, even if the development time is 1.3 times, the contact resistance is not further reduced due to the development residue of the resin, and a good conduction state cannot be obtained.

According to the present invention, by performing the lift-off treatment, it is not necessary to lengthen the developing time to obtain good conduction of the contact hole, and it is possible to prevent excessive development and film reduction. As a result, it is possible to achieve good contact hole conduction and good reflection characteristics over the entire substrate.

Thereafter, the etching of the titanium in the upper metal layer proceeds, and reaches the tantalum in the lower metal layer (pad 50). In this etching step, the upper metal layer where there is no development residue of the organic insulating film is rapidly etched, but the etching is substantially performed on the lower metal surface due to the etching selectivity between the upper metal and the lower metal. Can be stopped. For example, in the case of a stack of titanium / tantalum, the etching stops at the tantalum surface because the etching selectivity is 500: 1 or more. Thus, the bottom of the contact hole can be made smooth. The gate bus wiring 32 (gate electrode 3
In addition to the above, a material in which molybdenum, tungsten, niobium, or the like is added to tantalum as an impurity, a multilayer structure in which aluminum is covered with tantalum, or the like can be used as the material of the third and routing electrodes 37a). When an impurity is added to tantalum, a change in the etching selectivity with titanium is slight. When a gate wiring having a multilayer structure is used, if the surface of the pad 50 is tantalum, selective etching with titanium is performed. Can be performed well.

The opening of the contact hole must have an area of 400 μm ² or more in order to effectively remove the development residue of the organic insulating resin. Table 1
Then, when the opening area of the contact hole is changed,
3 shows a variation in contact resistance of a contact hole in a 300 × 300 mm substrate.

[0080]

[Table 1]

As can be seen from Table 1, when the area of the contact hole is 400 μm ² or more, the variation in contact resistance is small and a low resistance value is obtained. But,
Since the reflective electrode formed in the contact hole portion is in a mirror surface state, increasing the opening area of the contact hole darkens the display accordingly and lowers the display quality of the reflective liquid crystal display device.

FIG. 19 shows the change in brightness of the reflector when the ratio of the opening area of the contact hole to the area of the reflective electrode is changed. The brightness of the reflector was measured at 30 ° incidence and vertical light reception, and the brightness of the MgO film is shown as 100. As can be seen from FIG. 19, when the contact hole immersion becomes 8% or more of the reflective electrode area,
Brightness is below 100. Therefore, preferably, the opening area of the contact hole needs to be 8% or less of the reflective electrode area. For example, the area of the reflective electrode is about 240 × 120
In the case of μm ² , the opening area of the contact hole is 1440
μm ² or less.

As described above, the contact hole 43 is formed in the organic insulating film 42 as shown in FIG.
After performing the etching process, a reflective electrode 38 made of aluminum is formed in a predetermined region on the organic insulating film 42 as shown in FIG. The reflective electrode 38 is formed by, for example, a sputtering method in this embodiment. Reflective electrode 3
The material used for 8 may be any conductive material that reflects light, for example, silver or the like.

Next, an alignment film 44 is formed on the substrate 31 (FIG. 1). The alignment film 44 is coated with an alignment film material by printing or a spin coater so as to cover at least a region of the substrate 31 where the reflective electrode 38 is formed.
It is formed by firing and curing at ~ 180 ° C. When a vertical alignment film is formed, a vertical alignment film material is used. When a horizontal alignment film is formed, rubbing treatment or the like is performed after firing and curing of the alignment film. Thus, the lower substrate (active matrix substrate) 30a is completed.

As shown in FIG. 1, the upper substrate (counter substrate)
In 30b, a color filter 46 is formed on the substrate 45. In the color filter 46, the substrate 30
is in a position facing the reflecting electrode 38 of a formed magenta or green filter 46a, the filter 46b of the probe rack is formed at a position not opposed to the reflective electrode 38. A transparent electrode 47 made of ITO or the like is formed on the entire surface of the color filter 46, and an alignment film 48 is further formed thereon. The two substrates 30a and 30b are bonded to each other so that the reflective electrode 38 and the filter 46a are aligned with each other, and a liquid crystal 49 is injected between the substrates 30a and 30b.
Is completed.

The liquid crystal display device 3 manufactured as described above
0 indicates that the contact hole 43 formed for each pixel has a mirror state at the bottom. Therefore, the thickness of the liquid crystal layer of the liquid crystal display device 30 can be measured by using the above-described measurement method using laser light by using the bottom portion in the mirror surface state. FIG. 7 shows the result of the measurement using the laser light in this manner. As can be seen from FIG. 7, stable measurement is possible in the contact hole portion, and the thickness of the liquid crystal layer can be obtained from the position relative to the counter substrate.

(Embodiment 2) In this embodiment, a liquid crystal display device in which a switching element is an MIM element and an insulating resin film is formed using a non-photosensitive resin will be described.

FIG. 8 shows a switching element (MIM) 87.
Substrate (active matrix substrate) 8 on which is formed
FIG. 9 is a plan view of FIG.
It is sectional drawing of the board | substrate 80a seen from XI.

First, the configuration of the lower substrate 80a will be described. As shown in FIGS. 8 and 9, an insulating substrate 8 made of glass or the like is used.
A plurality of first wirings 81 made of tantalum or the like
Are provided in parallel with each other, and the first electrode 32 is provided to branch off from the first wiring 81. First wiring 81
Function as scanning lines. Similarly to the first embodiment, a pad 83 having a larger area than at least the contact hole 88 is formed on the substrate 80 at a portion where the contact hole 88 is formed. Pad 83
Are formed using the same material as the first wiring 81, and serve as a lower metal layer of the routing electrode 86.

As shown in FIG. 9, an insulating film 84 is formed to cover the first wiring 81 and the first electrode 82. In this embodiment, the insulating film 84 is formed by anodizing tantalum, which is a material of the first wiring and the first electrode, at a voltage of 25 V to 40 V. On the first electrode 82 covered with the insulating film 84, a second electrode 85 made of titanium, molybdenum, aluminum, or the like is formed. First electrode 82, the insulating film 8 4, and the second electrode 85
Thus, the MIM element 87 is formed.

The contact hole 88 on the substrate 80
In the portion where is formed, a routing electrode 86 is formed so as to cover the pad 83. The routing electrode 86 is connected to the second electrode 85. In the present embodiment, as shown in FIG. 8, the routing electrode 86 is formed simultaneously with the patterning of the second electrode 85, and the routing electrode 86 is formed integrally with the second electrode 85.

The first wiring 81 and the first electrode 82 covered with the insulating film 84, the second electrode 85, and the routing electrode
An organic insulating film 89 made of a polyimide-based non-photosensitive resin is formed on the entire surface of the substrate 80 so as to cover 86. A contact hole 88 is formed in the portion of the routing electrode 86 of the organic insulating film 89. Also, the organic insulating film 8
In the region where the nine reflection electrodes (pixel electrodes) 90 are formed,
The projection 89a is formed.

On the organic insulating film 89, a reflective electrode 90 made of aluminum or the like is formed so as to cover the region where the protrusion 89a is formed and the contact hole 88.
The reflection electrode 90 is connected to the routing electrode 86 by a pad 83 in the contact hole 88.

Next, a method of manufacturing the reflection type liquid crystal display device according to the second embodiment will be described with reference to the drawings, focusing on a method of forming the active matrix substrate 80a.

First, an insulating substrate 80 made of glass or the like is used.
On top of this, elements such as the MIM element 87, the pad 83, and the routing electrode 86 are formed by an ordinary method. In this embodiment, as the substrate 80, for example, a glass substrate having a trade name of 7059 manufactured by Corning and having a thickness of 1.1 mm is used.

When the MIM element 87 is formed, a pad 83 which is a metal layer having at least a larger area than the contact hole is formed in a portion where the contact hole 88 is to be formed. Further, a routing electrode 86 is laminated thereon.

The pad 83 becomes a lower metal layer in the contact hole portion. In this embodiment, the pad 83 is made of the same material as the first electrode 82 of the MIM element 87, preferably, tantalum .
Are formed have use. As a result, the first wiring 8
The first electrode 82 and the pad 83 can be formed by patterning at the same time.

The routing electrode 86 becomes an upper metal layer in the contact hole. Leading electrode 86
Uses the same material as the second electrodes 85 of the MIM element 87, preferably formed by using titanium. The second electrode 85 and the routing electrode 86 may be patterned at the same time. In this way, as shown in FIG. 10A, at the portion where the contact hole is formed, at least two layers made of different metals are stacked.

The substrate 80 on which each element is formed as described above
Then, as shown in FIG. 10A, a non-photosensitive resin is applied by a spin coating method, and post-baking is performed to form an organic insulating layer 101. As the organic insulating layer 101, a polyimide non-photosensitive resin is used, and preferably from 500 rpm to 3000 rpm by a spin coating method.
m. In this embodiment, it is 30 at 1300 rpm.
For 2 seconds, the thickness of the organic insulating layer 101 is about 2.5 μm
It is applied so that it becomes. Post bake is 23
Performed at 0 ° C. for 90 seconds.

Next, on the glass substrate 80 on which the organic insulating layer 101 has been formed, the same photoresist 102 as the photoresist used when forming the MIM element 87 is applied by spin coating, for example, at 90 ° C. for 60 seconds. Prebake. In the present embodiment, OFPR800 manufactured by Tokyo Ohka Co., Ltd. is used as the photoresist, and the thickness is 3.2 μm.
m.

Subsequently, the photoresist 102 is exposed using a photomask in the same manner as in the case of exposing the photosensitive resin layer in the first embodiment. For example, as shown in FIG. 6, the photomask 13 2 different sizes of the circular pattern holes 13a and 13b are formed in the plate member 13c
Can be used. Further, in order to make the metal layer (reflective electrode 90) formed at the bottom of the contact hole 88 a mirror surface state, it is necessary that a circular pattern hole is not arranged in the photomask 13 at a portion corresponding to the contact hole.

Next, for example, a photoresist 102 was prepared using a developer having a TMDH concentration of 2.38% manufactured by Tokyo Ohka Co., Ltd.
Is developed. As a result, as shown in FIG. 10B, fine convex portions 104 of the photoresist are formed on the organic insulating layer 101 in correspondence with the pattern holes 13a and 13b.
Many a 'and 104b' are formed.

Next, the organic insulating layer 101 is dry-etched using the photoresist convex portions 104a 'and 104b' as a mask, and the convex portions 104a 'and 104b' are transferred to the organic insulating layer 101. After that, the convex portions 104a 'and 104 of the photoresist are formed using an alkaline stripper.
Remove b '. As a result, as shown in FIG. 10C, convex portions 105a ′ and 105b ′ patterned from the organic insulating layer 101 are formed on the substrate 80. In this embodiment, O ₂ is used for dry etching.
Gas is used, and the selectivity between the photoresist 102 and the non-photosensitive resin 101 is 1: 1. After the etching is completed, the upper ends of the convex portions 105a 'and 105b' are angular.

Next, as shown in FIG.
On the 0, the same non-photosensitive resin with the organic insulating layer 101 is applied by spin-coating how to form the organic insulating film 103. Preferably, 1000 rpm to 3000 rpm
Spin coat with. In this embodiment, spin coating was performed at 2000 rpm for 30 seconds, and post-baking was performed at 230 ° C. for 90 seconds.

Next, a photoresist 106 is spin-coated on the glass substrate 80 on which the organic insulating film 103 is formed, and prebaked at, for example, 90 ° C. for 60 seconds.

[0106] Then, for example, such as a photomask 16 shown in FIG. 5, using a photomask on which a pattern is formed in the contact hole, exposed and developed photoresist 106. As a result, a contact hole pattern of a photoresist is formed on the organic insulating film 103 as shown in FIG. Next, using the photoresist pattern as a mask,
A contact hole 88 is formed in the organic insulating film 103 by performing a dry etching process similar to the formation of a ′ and 105b ′. By the above processing, FIG.
As shown in FIG.
An organic insulating film 89 composed of 05a 'and 105b' and the organic insulating film 103 formed on these convex portions is formed.

In the dry etching step, the dry etching proceeds faster in the central portion of the substrate than in the peripheral portion of the substrate due to the difference in plasma density in the etching apparatus. In particular, the difference in the etching rate between the four corners and the center of the substrate is large. Table 2 shows that the 320 m
5 shows the variation in the reflection characteristics of the reflection plate within a substrate of mx 400 mm.

[0108]

[Table 2]

In Table 2, the etching time is shown as a relative value when the etching time at which the best reflection characteristics are obtained is set to 1. As can be seen from Table 2, by appropriately selecting the etching time, the variation in the reflection characteristics can be suppressed within 10%.

The following steps are the same as those in the first embodiment.

The substrate 80 is immersed in an etching solution for etching the uppermost layer (the lead-out electrode 86 in this embodiment) of at least two metal layers stacked in the contact hole portion. Upper layer metal and lower layer metal (in this embodiment,
Due to the etching selectivity with the pad 83), the etching is substantially stopped on the lower metal surface, and the bottom of the contact hole 88 is formed in a smooth shape.

[0112] Here, the difference in the plasma density in the dry etching process for forming the contact hole 88, etching Tsu der somewhat insufficient in the substrate peripheral portion
Also, etching residue (organic insulating film 103) is lifted off by impregnation of the etchant in the wet etching process of the next upper metal layer. Therefore, it is not necessary to lengthen the dry etching time in order to obtain good conduction of the contact hole in the peripheral portion of the substrate, so that it is possible to prevent the contact hole from being enlarged due to the regression of the resist in the central portion of the substrate and to reduce the thickness of the resin layer. be able to. As a result, it is possible to achieve good contact hole conduction and good reflection characteristics over the entire substrate.

For example, the 400 formed by the dry etching process with an etching time of 1 in Table 2 above.
In the reflector having a contact hole of μm ² , when the lift-off treatment is not performed, the contact resistance is 5 to 3
5Ω. By performing the lift-off process according to the present invention, the contact resistance can be set to 3 to 5Ω over the entire substrate. Therefore, it is possible to suppress the variation in the reflection characteristics within the substrate to within 10% and to form a contact hole with good conduction in the entire substrate.

As the lower metal layer in the contact hole portion, in addition to the above-described tantalum, as described in the first embodiment, a material obtained by adding an impurity to tantalum may be used . For example, in JP-A-7-20500 and JP Inoue et al., As the first electrode of the MIM element, silicon, one from among the tetravalent following elements such as aluminum, and tungsten, chromium, iron, manganese, rhenium And tantalum to which one kind of impurity is added from elements having six or more valences. Also, Japanese Unexamined Patent Publication No. 7-925
In Japanese Patent Publication No. 02, Inami proposes adding zirconium to tantalum of the first electrode of the MIM element. Such a material containing tantalum as a main component also has a sufficiently high selectivity with respect to titanium, and can be used as a material of the first electrode in the liquid crystal display device of the present invention.
For example, tantalum containing 50 atomic% or less of nitrogen, 1
Tantalum containing 0 at% or less of silicon and tungsten, or tantalum containing 10 at% or less of at least one element of tetravalent or less and at least one element of hexavalent or more can be used.

Next, a reflection electrode 90 made of aluminum is formed in a predetermined region on the organic insulating film 89 in which the contact hole 88 is formed. The reflective electrode 90 is formed by, for example, sputtering in this embodiment. Reflective electrode 9
The material used for 0 may be a conductive material that reflects light, for example, silver or the like. Reflective electrode 9
Numeral 0 is connected to the routing electrode 86 by the pad 83 in the contact hole 88.

Thus, the active matrix substrate 80a shown in FIG. 9 is completed. In the liquid crystal display device according to the second embodiment as well, similarly to the liquid crystal display device 30 according to the first embodiment, a bright display is realized by appropriately selecting the opening area of the contact hole 88. Further, the bottom of the contact hole 88 formed for each pixel has a mirror surface state. Therefore, the thickness of the liquid crystal layer can be measured by using the above-described measurement method using laser light by utilizing the bottom portion in the mirror surface state.

The present invention is not limited to Embodiments 1 and 2, and a reflection plate may be formed using a non-photosensitive resin on an active matrix substrate on which TFT elements are formed. A reflective plate may be formed using a photosensitive resin on the active matrix substrate on which the MIM elements are formed.

[0118]

According to the present invention, even in a large substrate of 300 × 300 mm or more, a contact hole having good electrical connection is formed over the entire substrate, and a reflection plate having good scattering characteristics over the entire substrate is provided. since formation is able Ru to enables the production of reflection type liquid crystal display device of good display characteristics using a large-sized plate. In addition, even if a reflection plate having a high scattering effect is provided in the liquid crystal cell substrate, the thickness of the liquid crystal layer can be measured. A display device can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a part of a reflection type liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a plan view of the active matrix substrate shown in FIG.

3 (a) to 3 (f) are views showing a method for manufacturing a reflection type liquid crystal display device according to one embodiment of the present invention.

FIGS. 4A to 4C are diagrams illustrating a method of manufacturing a reflective liquid crystal display device according to one embodiment of the present invention.

5 is a plan view showing an example of photomask shown in FIG. 3 (f).

FIG. 6 is a plan view showing an example of the photomask shown in FIG. 3 ( b ).

FIG. 7 is a diagram showing a result of measuring a liquid crystal layer thickness of a reflection type liquid crystal display device according to one embodiment of the present invention.

FIG. 8 is a plan view showing a part of an active matrix substrate of a reflection type liquid crystal display device according to another embodiment of the present invention.

FIG. 9 shows a configuration in which the active matrix substrate shown in FIG.
It is sectional drawing seen from cutting surface line XI-XI.

FIGS. 10A to 10F are diagrams showing a method of manufacturing a reflection type liquid crystal display device according to another embodiment of the present invention.

11A is a plan view showing a part of an active matrix substrate of a conventional liquid crystal display device, and FIG. 11B is a plan view of the conventional active matrix substrate shown in FIG. It is sectional drawing seen from.

FIG. 12 is a diagram schematically showing the entire active matrix substrate shown in FIG. 11;

FIG. 13 is a diagram showing a cross-sectional shape of a reflector formed by heating an aluminum alloy and removing a protruding material by etching in a conventional liquid crystal display device.

FIG. 14 is a cross-sectional view illustrating an example of a reflection plate in a conventional liquid crystal display device.

FIG. 15 is a cross-sectional view showing another example of a reflector in a conventional liquid crystal display device.

FIG. 16 is a view schematically showing an optical system for measuring the thickness of a liquid crystal layer of a liquid crystal display device.

FIG. 17 is a diagram showing the result of measuring the thickness of a liquid crystal layer using a reflector having unevenness in a conventional reflective liquid crystal display device.

FIG. 18 is a diagram showing the dependence of the reflection characteristics of the reflector and the contact resistance of the contact hole on the development time.

FIG. 19 is a diagram showing the reflection characteristics of the reflector with respect to the ratio between the area of the reflector (pixel electrode) and the area of the contact hole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 31 Insulating substrate 32 Gate bus wiring 33 Gate electrode 34 Gate insulating film 35 Semiconductor layer 36 Source electrode 37 Drain electrode 37a Routing electrode 40 TFT 41 Contact layer 42 Organic insulating film 42a Convex part 43 Contact hole 38 Reflection electrode 50 Pad

Continuation of the front page (56) References JP-A-6-273800 (JP, A) JP-A-62-76653 (JP, A) JP-A-63-2855953 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) G02F 1/1335 520 G02F 1/1343 G02F 1/1365 G02F 1/1368

Claims (2)

(57) [Claims] A first substrate having a plurality of reflective electrodes;
A method for manufacturing a reflective liquid crystal display device, comprising: a second substrate having a light-transmitting electrode; and a liquid crystal layer disposed between the first and second substrates. Forming a switching element for supplying a voltage signal for display to the reflective electrode on the insulating substrate; and a routing electrode connected to the switching element and extending below the reflective electrode, wherein at least a part of the wiring electrode 2
Forming a routing electrode on which at least different kinds of metals are laminated; forming an insulating resin layer on the switching element and the routing electrode; and laminating the two or more different metals of the routing electrode. Forming a contact hole in the insulating resin layer on the region; performing etching using an etchant of a metal on the top layer of the routing electrode, and partially removing the top metal layer at the bottom of the contact hole; Or removing the residue of the insulating resin together with the uppermost metal layer by removing until reaching the metal layer therebelow; and corresponding to each pixel on the insulating resin layer so as to cover the contact hole. seen containing a step of forming a reflective electrode, a and the step of forming the insulating resin layer, the reflective electrode
A region where the contact hole is formed.
Except for the area to be formed, a circle made of insulating resin
Forming a convex pattern, and forming the circular convex pattern.
On the turn, apply the same insulating resin to form a second insulating resin layer
Forming the contact hole.
The contact hole is formed in the second insulating resin layer.
It is, in the step of forming the reflective electrode, the insulating trees
The reflective electrode formed on the resin layer has a scattering property,
The reflective electrode is mirror-shaped at the bottom of the contact hole.
And the reflection of the mirror surface state at the bottom of the contact hole
By using the light reflected by the electrodes, the liquid
A method for manufacturing a reflection type liquid crystal display device, comprising a step of measuring a thickness of a crystal layer. 2. A first substrate having a plurality of reflective electrodes,
A second substrate having a light-transmitting electrode;
Liquid crystal layer disposed between two substrates
A method for manufacturing a display device , comprising: supplying a voltage signal for display to the reflective electrode on an insulating substrate.
Forming a switching element that connects to the switching element and extending under the reflective electrode.
A wound electrode, wherein at least a part of the
Forming a routing electrode with multiple types of different metals stacked
And an insulating resin layer on the switching element and the routing electrode.
Forming , and the two or more different metals of the routing electrode are laminated
Contact holes are formed in the insulating resin layer on the
Using a metal etchant on the top layer of the routing electrode
Etching is performed, and the bottom of the contact hole is etched.
Reach top metal layer partially or below
By removing it until the uppermost metal layer
Removing the residue of the insulating resin; and covering the insulating resin layer so as to cover the contact hole.
And forming a reflective electrode corresponding to the pixel, the etchant used in the step of etching,
A mixture containing 0.25% to 1.00% hydrofluoric acid.
Ri, in the step of forming the reflective electrode, the insulating trees
The reflective electrode formed on the resin layer has a scattering property,
The reflective electrode is mirror-shaped at the bottom of the contact hole.
And the reflection of the mirror surface state at the bottom of the contact hole
By using the light reflected by the electrodes, the liquid
A method for manufacturing a reflection type liquid crystal display device, comprising a step of measuring a thickness of a crystal layer.