JP3372882B2 - Method for manufacturing substrate in reflective liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a personal computer
Reflective liquid crystal used for display means such as computers
In display devicesBoardIt relates to a manufacturing method. [0002] 2. Description of the Related Art Recently, OA of personal computers and the like has been developed.
(Office Automation) Equipment Porter
And the cost reduction of display devices has become an important issue.
Is coming. This display device has electro-optical characteristics
A pair of substrates each having electrodes formed thereon is provided with the display medium interposed therebetween.
Display by applying a voltage between the electrodes
This is a configuration for performing. As such a display medium, liquid
Crystal, electroluminescence, plasma, electro
Chromic etc. are used, especially liquids using liquid crystal.
Crystal Display (Liquid Crystal Disp)
1ay; LCD) can display with low power consumption.
For practical use, it is the most practical. The display mode and driving method of this liquid crystal display device
Considering the law, the super twisted nematic (Super
  Twisted Nematic (STN)
Simple matrix method can achieve the lowest cost
Belong to the category. However, in the future, information multimedia
As displays become more sophisticated, higher resolution displays and higher
Last, multi-tone (multi-power, full-power) and
Since a wider viewing angle is required, a simple matrix
It is thought that it is difficult to cope with this method. Therefore, a switching element is provided for each pixel.
(Active elements) and drivable scanning lines (scanning
Active matrices that increase the number of poles
Technology has been proposed.
High resolution, high contrast, multiple gradations, and wide viewing angle
Is being achieved. Active matrix liquid
In a crystal display device, pixels provided in a matrix
The electrode and the scanning line passing near the pixel electrode are active.
It is configured to be electrically connected via a switching element. As this active element, a two-terminal non-
Linear element (Metal-Insulator-Meta)
l; MIM) or a three-terminal nonlinear element.
A typical example of the active element currently used is a three-terminal element.
Thin Film Tran
(sistor; TFT). In recent years, demands for lower power consumption have been increasing.
, A transmissive liquid crystal display device that normally requires a backlight
Instead, reflection type liquid crystal display devices are being actively developed.
You. A bright display is obtained as a reflection type liquid crystal display device.
In order to achieve this, the display
Need to increase the intensity of light scattered in the direction perpendicular to the plane
is there. To achieve this, create a reflector with optimal reflection characteristics.
It is necessary to manufacture. To do so, use glass
Control to have optimal reflection characteristics on the surface of the substrate
Formed irregularities, and a thin film such as silver was formed on it
It is necessary to form a reflector. The method being practiced, for example, involves sensing
Light-shielding hands coated with optical resin and arranged with circular light-shielding areas
After exposing and developing the photosensitive resin through the step, heat treatment
By doing so, a plurality of convex portions are formed. And this
Forming an insulator protective film on the convex portion along the shape of the convex portion,
A reflector made of a metal thin film is formed on the insulator protective film.
It is a method. In addition, the reflection plate is placed outside the substrate (in a position opposite to the liquid crystal layer).
Influence of glass thickness, which is problematic when formed on the opposite side)
The double reflection caused by the reflection plate is formed inside the substrate.
By using a structure that also functions as a pixel electrode, that is, a reflective electrode
Solved. [0010] SUMMARY OF THE INVENTION A conventional reflection type liquid crystal table
In the display device, the reflective electrode is made of a material with high reflectivity.
Of course, it is preferable to configure
Is most suitable for Ag, but Ag has a high diffusion rate into the Si layer
Difficulty of diffusion and reaction to the base material
No. On the other hand, Al diffuses into the base and reacts.
Metallization in integrated circuits
Widely used for applications and good properties such as etching conditions
Therefore, Al is often used for the reflective electrode. this
Etching such Al reflective electrode film as a reflective electrode
In this case, use an etching solution consisting of nitric acid + acetic acid + phosphoric acid + water.
The wet etching method used as an etchant is applied.
You. By the way, in the above-mentioned conventional technology, the image
Wiring to send image signal and connection of driver for liquid crystal drive
The electrodes are required to have high resistance by oxidizing the connection parts in a later process.
Used for transparent electrode parts for the purpose of preventing
Is used. When a reflective electrode is formed on the above-mentioned substrate
In particular, in the mass production process, special
In addition to using film forming means, partial film formation of Al
Is not possible, and the Al film covers the ITO
The film is formed on the entire surface of the liquid crystal panel including the liquid crystal panel. This reflective electrode film
When wet etching is used, the following problem occurs. one
In general, thin films have an order of magnitude less lattice defects than bulk materials.
Many differences lead to imperfect crystal structures and therefore reflections
Many pinholes and active regions are generated in the electrode film. Now, as shown in FIG.
An ITO electrode 41 and an Al electrode 40 are laminated on a substrate 1.
The Al electrode 40 into a predetermined shape
In this case, as shown in FIG.
Will be used. However, at this time, resist
When exposure and development are performed to form the film 5, an alkali-based
Al electrode 40 is damaged by using
The active region and the pin shown in FIGS.
Corrosion and growth of holes (hereinafter referred to as pinholes 7)
This will help (see FIG. 23C). as a result,
The developer 6 is simultaneously in contact with the ITO electrode 41 and the Al electrode 40.
Then, a battery system as shown in the schematic diagram of FIG.
You. Due to the reaction by this battery system, the Al electrode 40 and IT
Since the O electrode 41 is corroded and dissolved, this is
Production yield and, consequently, the production yield of reflective liquid crystal display devices.
Make sure to lower. In addition, about this phenomenon,
Technical report: No. 44, March 1990, etc.
Therefore, the description is omitted here. The present invention solves such problems of the prior art.
It was decided to improve the manufacturing yield.
And its production in a reflective liquid crystal display device
It is intended to provide a fabrication method. [0016] [Means for Solving the Problems]Of the present inventionReflective liquid crystal display
One method of manufacturing a substrate in an apparatus is to use a translucent substrate.
Between a pair of substrates, the other being a substrate having a reflective electrode
The liquid crystal layer exists on the surface and the reflection formed adjacent to the liquid crystal layer
Electrodes andA bus wiring connected to the reflection electrode;
Connection electrode connected to the end of the wireReflective liquid crystal table
In the method of manufacturing a substrate having the reflective electrode of the display device,
Bus wiring is formed on a substrate for forming the reflective electrode.
While formingConnecting electrodes made of ITO are connected to the bus
Formed so that it partially overlaps the end of the lineProcess and next
so,An interlayer insulating film made of a photosensitive resin is formed on the connection electrode.
In the displayed state, the part other than the pixels in the display area
Form to existProcess and thenAcross the board
Made of Mo or an alloy containing Mo as a main component
The protective metal film and the reflective electrode film made of Al are continuously
FormProcess andNext, the reflective electrode film and the protective metal film
With an etchant consisting of nitric acid + acetic acid + phosphoric acid + water
At the same time by patterning on the interlayer insulating film.Reflection
Forming a pole and then connecting the connection electrodeProtective metal
filmRemoving and expressing
The above object is achieved. [0017] [0018] [0019] [0020] [0021] [0022] [0023] [0024] [0025] [0026] [0027] [0028] [0029] [0030] [0031] [0032] The operation of the present invention will be described below. In the present invention, as shown in FIG.
After forming an ITO electrode to be the connection electrode 3 in FIG.
(B) and (c), an Al electrode serving as the reflection electrode 4
Cover the connection electrode 3 made of ITO before the formation of
The above problem is solved by forming the protective film 9.
In addition, the reflection formed on the connection electrode 3 made of ITO
The Al electrode for the electrode 4 and the protective film 9 are temporarily
The final form shown in FIG. 2 (f)
The shape of the connection electrode 3 made of ITO is
Become. As a metal film used for such a purpose,
For example, Mo and Mo alloys are known.
This is described in detail in JP-A-3-246524.
You. However, Japanese Patent Application Laid-Open No. 3-246524 discloses a wiring structure of a pixel portion.
There is a description about the
There is no disclosure of any problems arising in the connection terminals.
No. [0036]In addition,Connect before the process of forming the reflective electrode
By forming a protective film on the top of the electrode,
It is possible to prevent the electrode from coming into contact during the manufacturing process
Becomes [0037]Also,Protective metal after forming interlayer insulating film
By forming a film and then forming a reflective electrode film, the same
Continuous film formation in the film formation process becomes possible, and the film formation process is one step
There is an effect that can be shortened. [0038]Also,Form a protective film with a metal film and
Optimization of the etch selectivity between materials used in the process
With this, it is possible to perform the etching process continuously.
You. Therefore, for the purpose of removing the protective film, a new
There is no need to perform a photolithography process, reducing the number of processes
It is. [0039]Also,Switch between reflective electrode and bus wiring
Providing a switching element (for example, MIM, TFT, etc.)
As a result, the limitation on the number of scanning lines is greatly reduced.
Increase the degree of freedom in designing the LCD display mode,
There is an effect that high definition can be achieved. [0040]Also,Amorph among switching elements
By using TFTs using Si such as
As the voltage ratio applied to the liquid crystal can be increased,the above
effectHas the effect of being able to exert more. [0041]Also,Make the interlayer insulating film larger than the display area
By setting it as a region, the reflective electrode remaining as the final form
Between the connection electrode and non-protective metal
A contact area can be formed. This area is the reflective electrode
And processing the protective film for protecting the connection electrode into a predetermined shape
(When the exposure is misaligned in the photolithography process,
Margins such as over-etching in the
This has the effect of contributing to an improvement in the yield rate. [0042]Also,The above-mentioned interlayer insulating film is used
For example, by forming so as to cover the bus wiring,
The ability to form reflective electrodes on bus wiring
Therefore, the aperture ratio can be increased, and the display brightness can be increased. [0043]Also,Using a photosensitive resin for the interlayer insulating film
Processing of the interlayer insulating film only by the photolithography process
It is possible, and the inorganic insulating film
Consider the effect on the substrate because a highly reactive acid is used
Need to be used, and for non-photosensitive organic materials,
Dry etching, ashing, etc. after triso
Simpler and less expensive than required
Photosensitive as interlayer insulating film because it can be processed in the process
The effectiveness of using the conductive resin material is understood. [0044]AlsoThe photosensitive resin film below the reflective electrode
By forming a number of concavo-convex shapes, light
It becomes possible to form a reflective electrode having diffusivity.
This prevents a reduction in the resolution of the displayed image and the occurrence of shadows.
Has an effect. [0045]Also,By using ITO as the connection electrode
Caused by various subsequent processes and stagnation in the process.
High resistance due to oxidation of the terminal part
Becomes [0046]Also,According to the manufacturing method, the electrode potential
Extremely large ITO and Al that are easy to form a local battery system
Without special processes such as mask depot, and
It is also possible to prevent the occurrence of electrolytic corrosion.
To easily use Al with excellent workability and reflectivity.
It becomes possible. [0047]Also,When the protective metal film and the reflective electrode are
Materials and etchers that are etched by etchants
Continuous film formation, continuous film formation
Equivalent to the step of not forming a protective metal film by etching
Production with a small number of processes becomes possible. [0048]Also,Protective metal film and reflective electrode and their
An example of a combination of etchantsAs a protective metal film
And Mo or an alloy containing Mo as a main component,Mo
And Al are the aforementioned nitric acid + acetic acid + phosphoric acid + water
Both are etched with chant, and the process up to
It is a combination of materials that conforms to. Also, nitric acid + acetic acid
The etchant consisting of + phosphoric acid + water is generally used for liquid crystal display
Is less reactive with each metal material that composes the device.
There is little need to consider the effect on the components,aboveManufacture
This is the most effective combination in the process. More Mo
Is used as an alloy with other metals, and
There is an effect that the difference in the chin rate can be adjusted. [0049]Also,Can be used as protective metal filmMetal material
When the material is Ti or an alloy containing Ti as a main component,
Electrolyte such as developer should be in contact with Al and ITO at the same time
No electrolytic corrosion between Al and ITO can be prevented
You. [0050]Also,Reflective electrode conducts through protective metal film
PartIf they are in contact, The reaction between the reflective electrode and the conductive part
Therefore, the reflective electrode is not eroded. [0051]Also,Connect the output electrode of the switching element to the switch.
At least one of the materials of the signal wiring of the switching element
From kindIf it forms, The output voltage of the switching element
Process without the need for new steps to form the poles
Can be shortened. [0052]Also,Output electrode should be formed by ITO
With the above, without deteriorating the aperture ratio of the transmission type LCD, etc.
The process up to immediately before forming an insulating film includes the transmission type liquid crystal display device.
It can be created in the same way as the device. [0053] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, referring to FIGS.
An outline of the invention will be described. In FIGS. 1, 2 and 3, on the substrate
The interlayer insulating film formed on the
Omitted. About the method of forming this interlayer insulating film
Will be described in a fourth embodiment. FIG. 1 is a diagram showing a problem solved by the present invention.
is there. A large liquid crystal display device or an active element
The terminal of the added liquid crystal display device (hereinafter referred to as LCD)
When the part is roughly modeled, as shown in FIG.
And a signal bus wiring 2 and a signal input connection electrode 3
can do. An LCD having such a terminal portion is of a reflective type.
When manufacturing LCD, special processing such as mask depot
Unless performed, as shown in FIG.
The reflective electrode 4 is also formed. The reflection electrode 4 and the connection electrode
A common material used for the pole 3 is a reflective electrode.
Al is used for the pole 4 and ITO is used for the connection electrode 3.
You. Here, as described above, generally, a thin film is a valve.
In contrast to the pinhole, as shown in FIG.
There are many such as 7 and Al is both acid and Al
Has the property of being easily corroded. Therefore, from Al
Reflective electrode 4 is formed into a predetermined shape using a photolithography process.
In the case of processing, the developer 6 which is a solution having a strong force is used.
Corroded. At this time, the surface of the reflective electrode 4 made of Al
Pinholes 7 are most susceptible to corrosion, and FIG.
As shown in (c), the developer 6 passes through the pinhole or the like.
Also, it comes into contact with the connection electrode 3 made of ITO. The figure
5 in 1 (c) is a photoresist. FIG.
(C ′) is a partially enlarged view (cross-sectional view) of FIG.
You. The Al / developer /
The ITO portion is a type of local battery shown in FIG.
A system is formed and a reflection made of Al as shown in FIG.
Both the electrode 4 and the connection electrode 3 made of ITO are corroded.
(Hereinafter, this phenomenon is referred to as electrolytic corrosion). 8 in FIG.
Is a corrosion (electrolytic corrosion) part. To avoid this problem, in the present invention, FIG.
A reflective LCD is manufactured using the steps shown in FIG. As shown in FIG. 2A, the end in the present embodiment
The model of the child part is the same as the conventional one shown in FIG.
However, as shown in FIG.
Before the film formation (see FIG. 2C), at least
A protective film 9 is formed so as to cover the entirety of the ITO serving as the pole 3
You. As shown in FIG.
As shown in the photolithography process, the reflection electrode 4
Even if the developer 6 penetrates through the pinhole 7 or the like
The image liquid 6 does not pass through the protective film 9, and the ITO
Never come in contact with FIG. 2 (d ') is a part of FIG. 2 (d).
It is a minute enlarged view (sectional view). Therefore, after that, FIG.
As shown in (e), patterning of Al to be the reflection electrode 4 is performed.
However, the final form shown in FIG.
3 is not corroded. Formation of protective film 9 as described above
Uses photosensitive resin material in Japanese Patent Application No. 9-160311.
Is described, but when a resin material is used,
This resin material must be removed as the final form
New dry etching and ashing processes
This requires a photolithography process. In the present invention, the protective film 9 is a metal film,
By adopting the structure of Al / protective metal film / ITO
Solves the problem of electrolytic corrosion,
Depending on the choice of etchant, the photolithography process
This prevents the process from increasing. Hereinafter, the present invention will be described in accordance with embodiments. (Embodiment 1) Embodiment 1 will be described with reference to FIG.
You. Bus wiring 2 made of Ta shown in FIG.
Is formed and the connection electrode 3 made of ITO is formed.
As shown in FIG. 2 (b), a protective metal
Ti is deposited on the entire surface as a film 9 by a sputtering method,
Next, the ITO portion, which is the connection electrode 3, is not exposed.
Pattern other parts using photolithography process
Etch. The etchant at this time is (E
DTA + H_TwoO_Two+ NH _ThreeBus using Ta)
Wiring 2, connection electrode 3 made of ITO, and Ti
Etching selectivity with the protective metal film 9 is provided. Next, as shown in FIG.
4 was formed, and the film was formed as shown in FIG.
A photoresist 5 having a predetermined shape is formed by triso,
Etching with a solution consisting of nitric acid + acetic acid + phosphoric acid + water
You. Thereafter, as shown in FIG.
Is removed and, as shown in FIG.
Covered the connection electrode 3 by passing it through an etchant
The protective metal film 9 is removed, and the connection electrode 3 made of ITO is formed.
Is displayed. Each metal material and etch used in this embodiment
Table 1 below shows the selectivity for
When etching Ti, the etchant is
Does not work, and a similar etchant is used during Al etching.
And metal selection. [0069] [Table 1] Such an etchant and a metal material are used.
And formation and removal of the protective metal film 9 in the manufacturing process.
The connection electrode 3 made of ITO and
The reflective electrode 4 made of Al does not cause electrolytic corrosion,
The projection LCD can be manufactured. The above embodiment is merely an example.
Therefore, the manufacturing process of the present invention can achieve the same effect.
If it is, it is not limited to the above combination. (Second Embodiment) In the first embodiment, the protection is performed.
Ti is used for the metal film 9 and EDTA is used for etching.
+ H_TwoO_Two+ NH_ThreeWas used, but H_TwoO_Two, NH_Three
Considering that both are highly volatile,
Is not suitable. In the present embodiment, the protective metal film 9
The process employing Mo will be described again with reference to FIG.
You. The steps are the same as those in the first embodiment.
To cover the connection electrode 3 made of ITO in the terminal part.
To form a Mo layer as the protective metal film 9 (FIG. 2A).
And (b)), a film of Al which is the reflective electrode 4 is formed.
(See FIG. 2 (c)). Thereafter, as shown in FIG.
Photoresist 5 is formed into a predetermined shape using a photolithography process.
Is formed, Al which is the reflection electrode 4 is etched.
However, due to the etchant at this time, M
o is also etched. For this reason, as in the first embodiment, the reflective electrode 4
Etching to remove protective metal film 9 again after formation
This eliminates the need for a step and reduces the number of etching steps.
It becomes possible. That is, in FIG.
Of the process of FIG.
It is not necessary to perform the process and the final form
2 (f). Table 2 below shows each metal in this embodiment.
Shows selectivity between material and etchant. [0076] [Table 2] The above embodiment is merely an example.
Therefore, the manufacturing process of the present invention can achieve the same effect.
If it is, it is not limited to the above combination. (Embodiment 3) Referring to FIG.
This will be described with reference to FIG. In the present embodiment, the Ta value shown in FIG.
Bus line 2 is formed, and a connection terminal made of ITO is formed.
A reflective electrode 4 is provided on the glass substrate 1 on which the substrate 3 is formed.
When Al is formed, Mo which is the protective metal film 9 is changed from Mo →
Film formation is performed in the order of Al (see FIGS. 3B and 3C). This
Al / Mo laminated metal film (reflection electrode 4+
For processing the protective metal film 9) into a predetermined shape.
Patterning by a triso process (see FIG. 3D)
See). Also at this time, as shown in FIG.
The protective metal film 9 made of is a protective film, and the developer 6 is connected.
The electrode 3 is prevented from penetrating into ITO. This board
With an etchant consisting of nitric acid + acetic acid + phosphoric acid + water
Etching, Al, M as described in Table 2 above
o Since both are etched, the final shape shown in FIG.
State. As described above, the protective metal film 9 is reflected on the entire substrate.
A film is formed in the same manner as Al which is the electrode 4, and like Al and Mo,
Use a combination that can be processed by the same etchant
As described in Embodiments 1 and 2,
The film 9 covers the connection electrode 3 made of ITO at the terminal portion.
No photolithography process is required because a process for processing into a shape like this is not added.
Can be shortened by one process. Further, in the film forming process, Mo and Al are continuously
If the deposition is performed in a specific manner, the process shown in FIG.
3 (a) directly from FIG. 3 (a).
It is considered that In this case, the number of steps itself is shown in FIG.
Number of steps equal to the process without protective film described in
And corrosion of the connection electrode 3 made of ITO can be prevented.
Manufacturing process can be realized. The third embodiment is merely an example.
In addition, the manufacturing process of the present invention has a high selectivity with metals such as other wirings.
Combinations of materials that can be etched simultaneously
Is not limited to the third embodiment. FIG.
As shown in (a), the edge of the Al electrode 38 and the Mo film 37 is etched.
Reverse tapered cross-sectional structure generated due to difference in chin rate
For the problem of fabrication, if you optimize the etching conditions
In addition, metal such as Ta and Ti is mixed into Mo,
FIG. 4 (b) even when the method of adjusting the switching rate is adopted.
Can be realized. 39 in FIG. 4 (b)
Is an alloy layer of Mo and Ta (or Ti). (Embodiment 4) In this embodiment, FIGS.
4 on a reflective LCD using switching elements
Adopting the manufacturing process of the invention, and as a switching element
The case where a TFT is adopted will be described. FIG. 5A is a plan view of one pixel on the element-side substrate.
FIG. 5B is a diagram showing AB (single-dot chain) in FIG.
FIG. In FIG. 5A, 1 is a glass substrate, and 10 is a glass substrate.
Port bus wiring, 11 is a source bus wiring, and 17 is a TFT element.
The element 4 is a pixel electrode (reflection electrode) that also serves as a reflection plate. In this TFT element side substrate, FIG.
(B) As shown in FIG.
Gate electrode 20 and a gate insulating film made of SiNx
21 and the semiconductor layer 12 (i layer 15, n⁺Layer 14, etch
Stopper 16), Ti electrode 18a, ITO electrode 18b
A source electrode 18 formed by
a, drain electrode 19 formed of ITO electrode 19b
Are formed, and these constitute the TFT element 17.
You. The reflection electrode 4 formed on the interlayer insulating film 29
Is connected to the lower pixel electrode 13 through the contact hole 42.
The lower pixel electrode 13 is electrically connected.
It is electrically connected to the pole 19. A TFT element 17 and a gate are provided on the element side substrate.
Connection electrode 3 made of ITO on the terminal part and the source terminal part
In the process up to the formation of a conventional LCD,
Since there is no difference from the process,
Is omitted. In addition, the reflective electrode 4 should have a light diffusing property.
The process for forming the uneven shape on the interlayer insulating film 29 is also described.
Similarly, as described in JP-A-6-75238,
Photomask A (25) used in FIG. 6, Photomask
FIG. 7 is a schematic diagram of B (27), and FIG.
Stop writing. 6 (a) and 6 (b).
The scales of the photomasks A (25) and B (27) are
Adjusted the pattern to make it easier to understand visually
Therefore, the interval between the two patterns does not always match this.
No. Using a photosensitive resin, the interlayer beneath the reflective electrode 4
The above-described substrate having the fine irregularities formed on the insulating film 29 has
The reflective electrode 4 is formed by using any of the methods of the first to third embodiments.
If formed, it is ITO which is the connection electrode 3 and the reflection electrode 4
Al does not corrode and has a reflective
A substrate having poles 4 can be obtained.
By using it, the manufacturing process of the present invention can be made more effective.
It becomes possible. 1) The interlayer insulating film 29 is formed at least in the display area.
A (see FIG. 10) or more, and as shown in FIG.
As described above, the interlayer insulating film 29 is also provided between the lower pixel electrodes 13.
To exist. 2) As shown in FIG. 13 and FIG.
IT that is used as redundancy of bus wiring 2 or bus wiring
Redundant wiring 30 made of O is kept in interlayer insulating film 32
You. 3) ITO used as connection terminal 3
And the redundant wiring 30 of the bus wiring 2 (see FIG. 8C).
At least the position of the exposure means
Misalignment margin, over edge generated during etching
The interval should be longer than the amount of shift by the switch. Effects of using the methods described in the above 1) to 3)
Are shown below with reference to FIGS. [0093] Note that in this explanation, the explanation diagram is complicated.
In order to avoid this, the uneven shape to be formed on the interlayer insulating film 29 is
Not listed. In general, the signal bus wiring 2 is
Double wiring etc. are used as a redundant design for failure due to
However, it is necessary to use ITO as the redundant wiring 30.
There is. As with the terminal parts described above, this redundant wiring 3
It is also necessary to consider the corrosion between the 0 part and the reflective electrode.
If the manufacturing process proceeds without any processing at the time of
(A) As shown in FIG.
appear. However, this issue is similar to the terminal part
8 can prevent corrosion, and FIG.
(B) Final form without corrosion of the redundant wiring 30
Is obtained. However, in this case, the reflection electrode 4 itself is a conventional one.
The size of the pixel electrode is almost the same as that of the transmission type. Where anti
The projection type LCD displays by reflecting light from the front.
U. Further, when the reflective electrode 4 is formed adjacent to the liquid crystal layer,
In this case, the gate bus wiring 10 formed on the element-side substrate
8 and the source bus wiring 11 (in FIG.
High aperture ratio by forming the reflective electrode 4 on the top
It is generally well known that this can be achieved. Like this
When the reflective electrode 4 is not formed on the redundant wiring 30,
Compare with the case where reflective electrode 4 is formed up to wiring 30
As shown in FIG. 8C, the area of the reflective electrode 4 is large.
Significant differences occur. This difference is directly related to the LCD display brightness.
Therefore, naturally, the reflective electrode extends up to the bus line 2 or the redundant line 30.
More preferably, there is 4. Next, the display area 31 and the interlayer insulating film 29 are formed.
Regarding the area to be covered, here also 2 parts of bus wiring
It is necessary to pay attention to the redundant wiring 30 composed of ITO
There is. The display area 31 shown in FIG. 9 as a model
Reflective type having an interlayer insulating film 32 formed in a region other than
Consider an LCD. In this model, FIG.
As shown, the IT used as the redundant wiring of the bus wiring 2
O and ITO of the connection electrode 3 are integrally formed, and
It is an electrode 33. The method described in the first and second embodiments was used.
In the case, near the terminal of the interlayer insulating film 29 after the formation of the reflective electrode 4
The cross section of the terminal portion of FIG.
And the protective film 9 covers the ITO electrode 33 without any gap.
Ideally. However, in the actual manufacturing process, the interlayer insulating film
When processing the protective film 9 and the protective film 9 into a predetermined shape,
Misalignment during exposure in the lithography process, overrun during etching
-A shift from the designed value occurs due to etching or the like.
Therefore, the following problem occurs. (1) The protective film 9 was formed before the formation of the interlayer insulating film 29
In this case, as shown in FIG.
A portion 34 into which the protective film 9 enters is generated. (2) Also, as shown in FIG.
A gap 35 is generated between the protective layer 9 and the protective layer 9. As a result, in the case of FIG.
When removing 9, floating 34 a occurs in interlayer insulating film 29.
(See FIG. 11 (c1)), and in the case of FIG.
An ITO electrode 33 is provided in a gap 35 between the insulating film 29 and the protective layer 9.
Exposed area (before forming reflective electrode 4 made of Al)
Occurs, and the reflective electrode 4 made of Al and the ITO electrode 33
Electrolytic corrosion occurs due to the occurrence of a portion where
(C2)). The peeling of the interlayer insulating film 29 will be described later.
`` Film peeling '' in the temperature rise process, which should occur in the process
Production yield and reliability.
Is significantly reduced. After the formation of the interlayer insulating film 29, the protective film 9 is formed.
Is formed, the protective metal film 9 is patterned.
Whether or not the failure described in FIG.
To be reminded. FIG. 12 (a) shows an interlayer insulation similar to FIG. 11 (b).
An ITO electrode 33 was exposed between the edge film 29 and the protective film 9.
This is the case where the gap 35 occurs. FIG. 12 (b)
This is the case where the method of Embodiment 3 is used, but the interlayer insulating film 29 is used.
Of the protective film 9 due to the step between the terminal and the terminal portion.
Occurs. Also in this portion, the same as the gap 35 described above is used.
As a result, the ITO electrode 33 is exposed, and electrolytic corrosion is induced.
(See FIG. 12 (c)). To avoid such a problem beforehand,
1) to 3) are effective, and in that case, FIG.
A gap 35 between the interlayer insulating film 29 and the protective film 9 shown in FIG.
FIG. 13B shows a portion cut off due to a step of the protective film 29.
Redundancy made of ITO, excluding 36 ITO electrodes 33 in advance
Separation into wiring 30 and connection electrode 3 made of ITO
Thus, the occurrence of electrolytic corrosion can be prevented (see FIG. 13C). What
FIG. 14B is a perspective view of FIG.
FIG. 14 (a) is a plan view showing the observation point.
It is. [0105] Also, in the area other than the display area 31,
The insulating layer region 32 outside the display area 31
The effect of this is that the ITO film as the redundant wiring 30 is
It has the effect of increasing redundancy by leaving it in a wider area,
Cracks and pinholes occur at the end of the interlayer insulating film 29.
The corrosion progress below the display area 31
This has the effect of preventing it to some extent. In this embodiment, the active element is
TFT, photosensitive resin was used as interlayer insulating film,
The present invention is not particularly limited to this material.
For example, even if a two-terminal element such as MIM is used, the effect does not change.
The effect of the present invention is influenced by the type of the material of the interlayer insulating film.
It is not affected. In addition, the reflective electrode has light diffusion
For this reason, in the present embodiment, an uneven shape is formed in the interlayer insulating film.
However, the manufacturing method of the present invention depends on the surface shape of the interlayer insulating film.
Has no effect on the step, the shape itself is limited to the embodiment
However, it may be flat, for example. As described above, the TFT element 1 is provided on the element side substrate.
7. The gate terminal and source terminal are made of ITO
In the process until the connection electrode 3 is formed, the conventional L
There is no difference from the CD manufacturing process.
In this case, the pixel electrode becomes ITO, which gives light transmittance.
In general, ITO has higher electric resistance than other metals
It has become. In contrast, the present invention proposes
Reflective LCD 4 and a lower pixel electrode
13 does not need to have optical transparency, so it is necessary to use ITO.
There is no need to use a metal film having a lower resistance
It can be used for the pixel electrode 13. In the present embodiment, FIG.
As shown in (b), the lower part electrically connected to the reflective electrode 4
The pixel electrode 13 is connected to the source electrode 18a of the TFT or the drain.
The metal film (Ti) used as the electrode 19a is left as it is.
It shows the case of using. (Embodiment 5) In Embodiment 4 described above.
The reflective LCD does not need to transmit light from the back.
Therefore, using an opaque metal film for the lower electrode
He stated that there is an advantage that the lower electrode can have low resistance. However, the reflection type LCD substrate and the transmission
When sharing the LCD substrate, use a metal film for the lower electrode.
When used, this bottom electrode blocks light from the back.
Reduces the aperture ratio of the pixel part on the substrate of the transmissive LCD
Inconvenience. Conversely, transparent IT is used for the lower electrode.
When O is used, the bottom of the reflective LCD substrate is
Inconvenience that electrolytic corrosion occurs between the electrode and the reflective electrode
Will be. To avoid this, the reflective LCD substrate
Mass production requires the production of a transmissive LCD substrate separately
Will be impaired. That is, conventionally, the transmission type LCD
The aperture ratio of the pixel portion on the substrate is sufficiently improved, and
The voltage between the lower electrode and the reflective electrode on the reflective LCD substrate
Eclipse cannot be prevented.
Substrates and transmissive LCD substrates cannot be shared
Was. FIG. 15 is a sectional view of a pixel contacted with a pixel electrode.
One pixel portion on a conventional substrate having a contact electrode
Is schematically shown. In FIG. 15, for contact
The electrode 51 is connected to the output side of the TFT 52 and
It is connected to the pixel electrode 51 '. Each signal line 56,
Reference numeral 57 defines a plurality of pixel areas.
A lower pixel electrode 51 'is arranged for each region. FIG. 16A is a sectional view showing the vicinity of the TFT 52.
The structure is shown. On the lower pixel electrode 51 'and the TFT 52
As shown in FIG. 16B, the interlayer insulating film 54 and the reflection
Electrodes 53 are sequentially formed, and the reflective electrode 53 is
4 through the contact hole 54a.
51. Contact electrode 51 and TF
T52 and the like are formed on a substrate 58 via an insulating film 59.
ing. As shown in FIG.
Pinholes and cracks 55 occur at
Sometimes. Here, in addition to the pixel electrode 51 ', light transmission
Using a non-transient metal as the contact electrode 51
Electrolyte penetrates through pinholes and cracks
However, the contact electrode 51 serves as a protective metal film.
Functions to prevent electrolytic corrosion between pixel electrode 51 'and reflective electrode 53
are doing. A substrate having such a structure is suitable for a reflective LCD.
Opaque contact electrode 51
As the aperture ratio of the pixel portion of the transmissive LCD decreases,
Not suitable for type LCD. Assuming that the contact electrode 51 is
The function is also used for the pixel electrode 51 'without special provision
And transparent ITO is used for the pixel electrode 51 '.
Then, as shown in FIG.
As a result, pinholes and cracks occur in the reflective electrode 53, and FIG.
As shown in FIG. 7B, between the pixel electrode 51 ′ and the reflective electrode 53
Electrolytic corrosion occurs, and a large hole 55a opens. This electric erosion section
In the worst case, the contact hole
The pixel electrode 51 'of ITO disappears in the entire portion of 54a,
There is no electrical connection between the pixel electrode 51 'and the reflective electrode 53.
You. For this reason, conventionally, the substrate of the reflection type LCD and the transmission type L
The only way to make a common part of the CD substrate manufacturing process
could not. Incidentally, in the transmission type LCD, the reflection type LC is used.
Instead of the reflective electrode 53 corresponding to the upper electrode of D, ITO
Since the transparent electrode consisting of
Using ITO as electrode 51 'as contact electrode
However, even if it is connected to the transparent electrode that is the upper electrode,
A transparent electrode and a pixel electrode that doubles as a contact electrode
No electrolytic corrosion occurs between them. FIG. 18 shows a reflective LCD substrate and a transmissive LCD.
1 schematically illustrates a conventional manufacturing process for a CD substrate. Figure
18 (a) to 18 (d), the gate is formed on the substrate 64.
Electrode 65, gate insulating film 66, TFT (i-Si layer 6
7, n⁺An Si layer 68 and a channel protective layer 69).
Ti metal film 71 to be used as source and drain electrodes, etc.
Are sequentially formed. The process up to this point is the reflection type LCD
It is common between the substrate and the substrate of the transmissive LCD. FIGS. 18 (e) to 18 (g) show the reflection type LCD.
This is a process for manufacturing a substrate. FIG.
In the step (g), the pixel electrode 7 is removed from the metal film 71.
The source electrode 73 and the drain electrode 74 of the second and first layers
After the formation, an ITO film 75 is formed and this ITO film is formed.
A source electrode 76 and a drain electrode 77 in the second layer
Is formed. FIGS. 18 (h) to 18 (j) show the transmission type L
This is a process for manufacturing a CD substrate. FIG. 18 (h)
In steps (j) to (j), the first layer of the metal film 71
After forming the source electrode 73 and the drain electrode 74,
A TO film 75 is formed, and a pixel electrode is formed from the ITO film 75.
78, the source electrode 76 and the drain electrode 77 of the second layer
Has formed. In the case of a reflective LCD substrate, a reflective electrode
In order to prevent electrolytic corrosion between the pixel electrodes 72, the reflection of Al
The pixel electrode 72 connected to the pole is formed from the metal film 71
I have. In the case of a transmissive LCD substrate, the pixel section is opened.
To improve the aperture ratio, the pixel electrode 78 is made of transparent ITO.
It is formed from the film 75. As is clear from the description of FIG.
And between the reflective LCD substrate and the transmissive LCD substrate
More than two types of photomasks
It is. Here, the source electrode and the drain of the first layer are used here.
A Ti metal film is used as the rain electrode layer.
Using ITO film as source and drain electrode layers
However, if it is a low-resistance metal material, the first layer
And other types of metals may be used.
Then, an ITO film may be used. FIG. 19 shows a substrate of a reflective LCD and a transmissive LCD.
An example that is further simplified as a conventional manufacturing process of a CD substrate,
In other words, the source electrode and the drain electrode are formed from only one layer
FIG. 19 (a) to 19 (c)
In the above, a gate electrode 65 and a gate
Edge film 66, TFT (i-Si layer 67, n⁺Si layer 68, h
(Consisting of a channel protective layer 69). here
The process up to this is a reflective LCD substrate and a transmissive LCD substrate
Common among them. FIGS. 19D and 19E show the reflection type LCD.
This is a process for manufacturing a substrate. FIG. 19 (d),
In the step (e), a metal film 71 is laminated,
Drain from the metal film 71 to the pixel electrode 72 and the source electrode 73
An in-electrode 74 is formed. FIGS. 19F and 19G show transmission type LCDs.
This is a process for manufacturing a substrate. FIG. 19 (f),
In the step (g), an ITO film 75 is formed and
From the ITO film 75 to the pixel electrode 78, the source electrode 76 and
A drain electrode 77 is formed. As described above, the source electrode and the drain electrode have one layer.
Formed from a metal film of
When the pole is formed from a single layer of ITO film, a reflective LCD
Cannot be shared between the LCD substrate and the transmissive LCD substrate.
Not only do you need two or more different photomasks,
Two systems such as a film forming device and an etching device are required. As apparent from the description of FIG. 18 and FIG.
In addition, separate the reflective LCD substrate and the transmissive LCD substrate
If manufactured, mass productivity will be impaired. But
As described above, when a metal film is used for the lower electrode,
The aperture ratio of the pixel portion on the substrate of the oversized LCD decreases,
When transparent ITO is used for the lower electrode, the reflective LC
On the substrate of D, electrolytic corrosion occurs between the lower electrode and the reflective electrode
I do. Therefore, the reflective LCD substrate and the transmissive LCD
The only alternative was to make the substrates separately. The substrate of the reflection type LCD of this embodiment has a reflection type.
Figure 1 shows the manufacturing process of the LCD substrate and the transmission LCD substrate.
8 and in the range of the process shown in FIG.
The process up to the step immediately before laminating the insulating film can be shared.
Function. FIG. 20A shows the reflection type LC of this embodiment.
Disconnection near the pixel electrode 81 and the TFT 82 on the substrate D
2 shows a surface structure. Forming insulating film 89 on substrate 83
A pixel electrode 81 made of ITO and a TFT 8
2 is formed, and an interlayer insulating film is further formed as shown in FIG.
84, a protective metal film 85 and a reflective electrode 86 made of Al
The reflective electrode 86 and the protective metal film 85 are sequentially formed, and interlayer insulation is performed.
The pixel electrode 8 is formed through the contact hole 84a of the edge film 84.
Connected to 1. In the substrate of this embodiment having such a configuration,
The contact hole 84 is formed as shown in FIG.
Pinholes and cracks 88 are formed on the reflective electrode 86 at the portion a.
Occurs and the electrolyte penetrates into pinholes and cracks
Also, the penetration of the electrolytic solution is prevented by the protective metal film 85.
A station between the reflective electrode 86 of Al and the pixel electrode 81 of ITO.
No partial battery structure is formed, and the reflective electrode 86 is not formed.
No electrolytic corrosion occurs between the pixel electrode 81 and the
That the pixel electrode 81 is defective at the hole 84a
There is no. Moreover, since the protective metal film 85 is made of metal,
Between the reflective electrode 86 and the pixel electrode 81 by the protective metal film 85
Connection is not impaired. The substrate of this embodiment is of a reflection type LCD.
However, since the ITO pixel electrode 81 is used,
Even when used in transmissive LCDs, the aperture ratio of the pixel section does not decrease
Only If the substrate is used for a transmissive LCD,
Of ITO to replace reflective electrode in LCD
The electrode is made of ITO through the contact hole of the interlayer insulating film.
It will be connected to the pixel electrode 81. Therefore, the substrate of this embodiment is a reflective type LC.
Prevent electrolytic corrosion between lower electrode and reflective electrode on substrate D
Not only can it be
Aperture ratio of the pixel portion can be sufficiently improved. Change
This is especially true for the process immediately before laminating the interlayer insulating film.
Thus, the reflective LCD substrate, the transmissive LCD substrate, and the
It is possible to standardize the manufacturing process of these substrates. In this embodiment, the source electrode and the drain
The in-electrode is formed from only one layer of ITO.
These electrodes may have a two-layer structure of ITO and a metal film.
No. FIGS. 21 and 22 show the substrate structure of FIG.
Plan view and sectional view showing the adopted transflective LCD
It is. In this transflective LCD, on the substrate 91
An insulating film 92 is laminated, and an ITO pixel electrode 9 is formed thereon.
3, TFT 94, signal wiring 95, interlayer insulating film (not shown)
And the display electrodes 96 are formed. Display electrode 9
Reference numeral 6 denotes a two-layer Al reflective electrode 96a and Mo protective gold.
It comprises a metal film 96b and a transparent electrode 96c of ITO. Anti
The light emitting electrode 96a has a reduced metallic luster of the reflective electrode.
In order to get closer to the "white" state, light from all angles
Of light that is scattered in the direction perpendicular to the display screen even when light enters
In order to increase the number, irregularities are formed. The reflective electrode 96a and the protective metal film 96b are
In contact with the pixel electrode 93 through the contact hole of the inter-insulation film.
Has been continued. Al reflective electrode 96a and ITO pixel electrode
Since the Mo protective metal film 96b is interposed between the poles 93,
The occurrence of electrolytic corrosion between the emission electrode 96a and the pixel electrode 93 is prevented.
You. Under the substrate 91, a polarization / phase plate 97 and
A backlight 98 is overlaid. On the lower side of the substrate 101
Are the color filter 102 and the counter electrode 10 of ITO.
And a polarizing / phase plate 1 on the upper side of the substrate 101.
04 is overlaid. Between the substrate 91 and the substrate 101,
The liquid layer 105 is sandwiched. [0134] According to the present invention, connection with the reflective electrode is made.
The development of the resist film is performed while the electrode is in contact.
Therefore, the reflection electrode is Al and the connection electrode is I
Even if each is composed of TO,
No corrosion or dissolution due to the formation of a pond
Of a reflective liquid crystal display device controlled by a TFT array
Build yield can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram (cross-sectional view) showing a problem solved by the present invention, showing a process in which corrosion occurs in a terminal portion. FIG. 2 is a process cross-sectional view showing one example of a method for manufacturing a reflective liquid crystal display device of the present invention (Embodiments 1 and 2). FIG. 3 is an example of a method of manufacturing the reflective liquid crystal display device of Embodiment 3, in which not only the connection electrode but also the entire substrate is covered with a protective film, and the combination of the reflective electrode, the protective metal film, and the etchant is optimized. FIG. 7 is a process cross-sectional view showing a flow in a case where corrosion is prevented and the number of processes is shortened. 4A is a cross-sectional view of a laminated electrode when an Al / Mo laminated structure is etched, and FIG. 4B is a diagram showing Mo (Ti) (Ta).
FIG. 4 is a cross-sectional view of an Al / Mo laminated structure electrode when the Al is mixed or when the etching conditions are optimized. 5A and 5B are diagrams illustrating a configuration of a substrate when a TFT is used as a switching element, where FIG. 5A is a top view and FIG. 5B is a cross-sectional view taken along line AB in FIG. FIGS. 6A and 6B are schematic views (plan views) of a photomask used to form an uneven shape on an interlayer insulating film, where FIG. 6A is a photomask for forming unevenness and FIG. 6B is a photomask for smoothing; FIG. FIG. 7 is a process cross-sectional view showing a flow of a process of forming a concavo-convex shape on an interlayer insulating film. 8A and 8B are diagrams for explaining a problem caused by a difference in a formation range of an interlayer insulating film. FIG. 8A shows a case where a redundant wiring made of ITO does not take measures against exposed corrosion, and FIG.
When redundant wiring made of O is exposed and measures against corrosion are taken,
FIG. 3C is a cross-sectional view showing a case where a bus wiring is covered with an interlayer insulating film in addition to a lower pixel electrode. FIG. 9 is a plan view showing the entire liquid crystal panel. FIG. 10 is a sectional view showing a state in which an interlayer insulating film and a protective film ideally cover an ITO electrode. 11A is a cross-sectional view showing a case where a protective film enters under an interlayer insulating film, FIG. 11B is a cross-sectional view showing a case where there is a gap between the interlayer insulating film and the protective film, and FIG. ) Is a cross-sectional view showing a state in which the floating of the interlayer insulating film occurs in the case of (a), and (c2) shows a state in which the occurrence of electrolytic corrosion and the floating of the interlayer insulating film occur in the case of (b). It is sectional drawing. 12A is a cross-sectional view illustrating a case where there is a gap between an interlayer insulating film and a protective film, and FIG. 12B is a cross-sectional portion of the protective film due to a step between the interlayer insulating film and a terminal portion. FIG. 4C is a cross-sectional view showing the case, and FIG. 4C is a cross-sectional view showing the occurrence of electrolytic corrosion and the occurrence of floating of the interlayer insulating film. 13A and 13B are cross-sectional views showing a case where a gap is provided between a redundant wiring made of ITO and a connection electrode made of ITO by using the method of manufacturing a reflective liquid crystal display device of the present invention. FIG. 3C is a cross-sectional view showing a state where no electrolytic corrosion occurs. FIG. 14 (b) is a perspective view of FIG. 13 (c),
(A) is a plan view showing the observation point. 15 is a plan view schematically showing one pixel portion in a conventional substrate. FIG. 16 (a) is a cross-sectional view showing the vicinity of the TFT in FIG.
(B) is a perspective view showing a laminated structure of an interlayer insulating film and a reflective electrode. FIG. 17A is a cross-sectional view showing the vicinity of a TFT on another conventional substrate, and FIG. 17B is a perspective view showing a laminated structure of an interlayer insulating film and a reflective electrode. FIGS. 18A to 18D schematically show a conventional manufacturing process for a reflective LCD substrate and a transmissive LCD substrate, wherein FIGS.
7A to 7G show steps common to both substrates, FIGS. 7E to 7G show steps of a reflective LCD substrate, and FIGS. 7H to 7J show steps of a transmissive LCD substrate. FIG. 19 schematically shows another conventional manufacturing process of a reflective LCD substrate and a transmissive LCD substrate, and FIGS.
(C) shows a process common to both substrates, and (d),
(E) shows the steps of the reflective LCD substrate, and (f),
(G) is a figure which shows the process of the board | substrate of a transmission type LCD. FIG. 20A is a cross-sectional view illustrating the vicinity of a pixel electrode and a TFT on a substrate according to a fifth embodiment, and FIG. 20B is a perspective view illustrating a stacked structure of an interlayer insulating film and a reflective electrode. FIG. 21 is a plan view showing a transflective LCD employing the substrate structure of FIG. 20; FIG. 22 is a sectional view showing the transflective LCD of FIG. 21; 23 (a) to 23 (c) are process cross-sectional views for explaining a problem of the related art, and FIG. 23 (d) is a schematic diagram showing a battery system model. [Description of Signs] 1 Glass substrate 2 Bus wiring 3 Connection electrode 4 Reflecting electrode 5 Photoresist 6 Developing solution 7 Pinhole 8 Corrosion (electric corrosion) portion 9 Protective film (or protective metal film) 10 Gate bus wiring 11 Source bus Wiring 12 Semiconductor layer 13 Lower pixel electrode 14 n ⁺ layer 15 i layer 16 Etch stopper 17 TFT element 18 Source electrode 19 Drain electrode 20 Gate electrode 21 Gate insulating film 22 Light transmitting part 23 Light shielding part 25 Photomask A 27 Photomask B 29 Interlayer insulation film 30 Redundant wiring 31 Display area 32 Interlayer insulation film 33 formed in a region other than the display area 34 ITO electrode 34 Part to enter 35 Gap 36 Cut part 37 Mo film 38 Al electrode 40 Al electrode 41 ITO electrode 42 Contact hole 81 Pixel electrode 82 TFT 83 Substrate 84 Interlayer insulating film 85 Protective metal film 6 the reflective electrode

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-254714 (JP, A) JP-A-5-281533 (JP, A) JP-A-9-197433 (JP, A) 246524 (JP, A) JP-A-10-22546 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1343 G02F 1/1362 G02F 1/1345 G02F 1/1333 G02F 1/13 101

Claims (1)

(57) [Claim 1] A liquid crystal layer exists between a pair of substrates, one of which is a light-transmitting substrate and the other is a substrate having a reflective electrode. a reflective electrode formed Te, the reflective
A bus wiring connected to the electrode, and an end connected to the bus wiring
In a method of manufacturing a substrate having a reflective electrode of a reflective liquid crystal display device provided with a connected electrode , a bus electrode is formed on a substrate for forming the reflective electrode, and a connection electrode made of ITO is formed. The end of the bus wiring
Forming a portion so as to partially overlap the portion, and then forming an interlayer insulating film made of a photosensitive resin on the connection electrode
Is displayed, and pixels other than the pixels in the display area are displayed.
Forming Mo or Mo as the main component over the entire substrate.
Protective metal film made of an alloy and a reflective electrode made of Al
A reflective film and the protective metal film are successively formed by nitric acid + acetic acid +
Simultaneously with an etching solution consisting of phosphoric acid and water
Forming a reflective electrode on the interlayer insulating film by performing etching , and then exposing the connection electrode by removing an upper protective metal film , thereby producing a substrate in a reflective liquid crystal display device.