JPH0237320A - Liquid crystal display device and production thereof - Google Patents

Abstract

PURPOSE:To enhance light shieldability in spite of an excellent opening rate and to allow liquid crystal display with high image quality by forming a light shielding part based on a mark part formed by self-alignment to the point opposite to the metallic wiring layer constituting the element on the rear surface side of one of transparent substrates facing each other. CONSTITUTION:The element having at least metallic wiring layer 13 on the outer side surface of one transparent substrate 1 of the transparent substrates 1, 2 facing each other is provided. The metallic wiring layer 13 and the mark part 16 by the self-alignment are provided to the outer side surface of the one substrate 1 and the light shielding part 4 which shields the element is provided based on said mark part 16. The light shielding part 4 formed on the rear surface side of the substrate 1 is formed with the mark part 26 provided by the self-alignment as a reference. Coating of the desired part of the element with high accuracy is possible in this way and the high light shieldability is obtd. even if the opening rate is high. The light shielding part 4 is formed on the rear surface of the substrate 1 formed with the element and notching is formed on the light shielding 2 side facing said substrate with a liquid crystal in-between; therefore, the transparent substrates facing each other can be easily stuck to each other.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention has a liquid crystal driving element having a metal wiring layer on the inner surface of one of the opposing transparent substrates, and a light shielding portion on the outer surface. The present invention relates to a transmissive liquid crystal display device having a transmission type liquid crystal display device and a method for manufacturing the same.

[Summary of the invention]

The present invention provides a liquid crystal display device in which an element having at least a metal wiring layer is provided on the inner surface of one of the opposing transparent substrates, in which a light shielding portion is provided on the outer surface of one of the transparent substrates. The present invention aims to provide a liquid crystal display device which has a high light-shielding property and can improve image quality despite having an excellent aperture ratio.

In addition, the present invention forms an element having a metal wiring layer on the front side of a transparent substrate, and forms a semiconductor layer on the back side of the transparent substrate, and then forms a mark portion with the metal wiring layer of the element and a self-line. By forming a light shielding part using the mark part as a reference, high accuracy and N, a
The present invention provides a method for manufacturing a liquid crystal display device in which a light shielding portion can be formed in the liquid crystal display device and a transparent substrate facing the transparent substrate can be easily bonded to the liquid crystal display device.

[Conventional technology]

For example, an active matrix transmission type liquid crystal display device has a liquid crystal display section with a matrix electrode provided on a common substrate and a thin film transistor functioning as a liquid crystal drive circuit, and a counter electrode is placed on the surface opposite the substrate on which these elements are formed. It consists of a liquid crystal sandwiched between a substrate provided with a bridge.

However, in the above-mentioned liquid crystal display device, the thin film transistor has a convex shape compared to the liquid crystal display part, so when a voltage is applied to the thin film transistor, not only the liquid crystal in the liquid crystal display part but also the liquid crystal on the thin film transistor is aligned, causing the liquid crystal to become oriented. This will lead to deterioration of the display.

In addition, Ap electrodes are used as electrodes constituting thin film transistors.
If strong light is incident on the person, the j! Incident light is reflected by the electrodes, and the reflected light leaks into the liquid crystal display section, resulting in a decrease in the contrast of the liquid crystal display.

Furthermore, if very intense light is incident, gate leakage will also occur, resulting in problems with liquid crystal display.

Conventionally, in order to solve the above-mentioned problems, as shown in FIG.
In addition to forming an element 104 having a
A liquid crystal display is formed by forming a light shielding part 105 at a position corresponding to an element 104 having a light shielding part 3, and inserting a liquid crystal 106 between these parts, aligning them with precision so as not to overlap with the liquid crystal display part, and bonding them together. A device has been proposed.

[Problem to be solved by the invention]

However, when bonding together the transparent substrate 101 on which the liquid crystal driving element 104 is formed and the transparent substrate 102 provided with the light shielding part 105 that blocks light leaking from the liquid crystal driving element 104, the adhesive expands. , contraction, expansion errors due to temperature changes during bonding, and other various conditions during bonding, the liquid crystal driving element 104 and light shielding portion 10
5, and it is very difficult to accurately bond the liquid crystal driving element 104 and the light shielding part 105 together.

Therefore, if a liquid crystal display device is manufactured by bonding the transparent substrate 102 on which the light-shielding portion 105 is formed and the transparent substrate lot on which the liquid crystal driving element 104 is formed, taking into account the misalignment during bonding, the misalignment is anticipated. Light shielding part 1 made with
05 overlaps with the effective area of the liquid crystal display, it is reported that the aperture ratio decreases, brightness decreases, and image quality deteriorates.

In order to improve the above-mentioned problem, for example, there is a method of forming a light shielding part so as to overlap the liquid crystal driving element. In this method, the accuracy of overlapping the light-shielding part and the element is very good, but since the material of the light-shielding part is a conductor, short circuits may occur between the gate electrode, Al electrode, etc. that make up the element. There are 8 points, including that there is a high possibility of this, and that there is unevenness between the element and the substrate, causing light leakage in that area.

Therefore, the present invention provides a liquid crystal display device with a high aperture ratio and good contrast, and also allows elements and a light-shielding plate to be overlapped with high precision, and can be easily and favorably bonded to an opposing transparent substrate. The present invention provides a possible manufacturing method for a liquid crystal display device.

[Means to solve the problem]

The present invention provides a liquid crystal display device in which an element having at least a metal wiring layer is provided on the inner surface of one of the transparent substrates facing each other, wherein the metal wiring and the self-alignment line are provided on the outer surface of one of the transparent substrates. The device is characterized in that a mark portion is provided, and a light shielding portion is provided for shielding the element from light based on the mark portion.

The present invention also includes a step of forming an element having a metal wiring layer on the front side of a transparent substrate, and forming a semiconductor layer on the back side of the transparent substrate, and a step of forming a metal wiring layer of the element and a self-line in the semiconductor layer. The method is characterized in that it comprises a step of forming a mark portion, and a step of forming a light shielding portion with reference to the mark portion.

[Effect]

The light shielding part formed on the back side of the transparent substrate is formed based on the mark part provided by the Selfa line, so
It becomes possible to cover the desired part of the element with high precision,
Despite its excellent aperture ratio, it has high light-shielding properties.

In addition, a light-shielding part is formed on the back side of the transparent substrate on which the element is formed, and nothing is formed on the transparent substrate side that faces the liquid crystal, making it easy to bond the opposing three-light substrates together. can be done.

〔Example〕

Embodiments to which the present invention is applied will be described below with reference to the drawings.

As shown in FIG. 1, the liquid crystal display device according to the present invention has the following features:
A transparent substrate 1 on which a liquid crystal driving element 3 and a light shielding part 4 are formed.
and a transparent substrate 2 on which a counter electrode 5 is formed are pasted together with a liquid crystal 6 sandwiched between them so that the element 3 of the transparent substrate 1 and the transparent substrate 20 and the interdigital electrode 5 face each other. It is.

In this embodiment, glass substrates are used as the transparent substrates 1 and 2, but any other material that is normally used as a material for transparent substrates can be used.

The liquid crystal driving element 3 formed on the inner side 1a of the transparent substrate 1 is a thin film transistor that functions as a driving circuit of a liquid crystal display device, and a source region and a drain region are formed on the inner side la of the transparent substrate 1. An active layer 7 is provided on which the gate is disconnected. ! l! A gate electrode 9 is formed via I8. An insulating film 10 is formed over the entire inner surface 1a of the transparent substrate 1, including the active layer 7, gate electrode 9, etc. Openings 11 and 12 are formed in the insulating film 10 at locations corresponding to the formation portions of the source and drain regions of the active layer 7,
Eight in one opening 11! A metal wiring layer 13 is formed, and a matrix electrode 14 including an insulating film 10 formed on the transparent substrate 1 is formed in the other opening 12. An alignment layer 15 is formed on the inner side of the transparent substrate 1 on which the element 3 having the above-described structure is formed.

On the outer surface 1b of the transparent substrate 1 on which the element 3 having the above-mentioned structure is formed, a mark portion 16 is provided which is formed by a self-alignment with the metal wiring layer 13 constituting the element 3. This mark portion 16 is formed on the outer surface 1 of the transparent substrate 1 at the same time when forming the gate electrode 9 constituting the element 3.
Using the polysilicon film formed in b, the metal wiring layer 13 constituting the element 3 and the self-line are formed.

A light shielding portion 4 is formed on the mark portion 16 on the front surface side with the mark portion 16 as a reference. In particular, in this embodiment, the light shielding portions 4 are formed only at locations corresponding to the metal wiring 1'i13 for the purpose of preventing reflection of light from the metal wiring layer 13 caused by transmission of light.

However, the contrast decreases due to gate leakage,
The outer surface 1b of the transparent substrate 1 is arranged so as to cover the entire element 3 formed on the inner surface 1a of the transparent substrate I for the purpose of preventing screen deterioration caused by alignment of the liquid crystal in parts other than the liquid crystal display section. , the light shielding part 4 may be formed in a portion facing the element 3 so as to cover the entire element 3.

On the other hand, the element 3 is formed on the inner surface 2a of the transparent substrate 2, which faces the transparent substrate l on which the element 3 and the light shielding part 4 are formed, and is attached with the liquid crystal 6 sandwiched therebetween. A counter electrode 5 is formed on the entire surface of the transparent substrate 1 facing the matrix electrode 14 . An alignment layer 17 is formed over the entire surface of the counter electrode 5. The alignment layer 17 is formed for the purpose of improving the alignment of the liquid crystal 6 together with the alignment layer 15 of the transparent substrate 1 on which the element 3 is formed.

In this way, the light-shielding portion formed based on the mark portion formed by the metal wiring layer of the element and the self-alignment line can shield a desired portion of the element from light with high precision.

In addition, as mentioned above, the light shielding part 4 is provided on the outer surface side 1b of the transparent substrate 1.
and the inner surface 2a of the opposing transparent substrate 2.
A structure may be adopted in which a light shielding portion is formed at a location facing the element 3 .

Next, a method for manufacturing the above liquid crystal display device will be explained.

First, as shown in FIG. 2a, the liquid crystal driving element 22 is formed on the surface side 21a of one of the opposing transparent substrates 21 by a conventional method. This element 22 is a thin film transistor having source and drain regions and a gate electrode 25, and a metal wiring layer 29 made of Al is formed as a wiring layer.

Then, a matrix electric bridge 30 is formed over the entire surface including the element 22 and the insulating film 26 formed on the surface side 21a of the transparent base Fi21.
form.

In particular, since the gate electrode 25 constituting the element 22 is manufactured by the CVD method, the polysilicon layer 31 is formed on the back side 21b of the transparent substrate 21 at the same time as the gate electrode 25 is manufactured. Ru.

Next, as shown in FIG. 2, the back side 2 of the transparent substrate 21 is
1b, a positive type photoresist layer is formed on the surface of the polysilicon layer 31.

Then, ultraviolet rays are irradiated from the element 22 side of the transparent base Fi21. The metal wiring layer 29 constituting the thin film transistor is
Since ultraviolet rays are not transmitted through this metal layer vA1129 and the photoresist layer directly under the metal wiring N29 in the self-line is left unexposed. By developing this, a portion of this photoresist layer remains to form a resist mask 32.

Subsequently, as shown in FIG.
1 is etched to remove the polysilicon N31 other than the portion where the resist mask 32 is formed. Thereafter, the resist mask 32 is removed to form a mark portion 33 made of polysilicon. This mark portion 33 is
It is formed at a position corresponding to the metal wiring layer 29 forming part 2.

As described above, the mark portion 3 is formed on the back side 21b of the transparent substrate 21.
After forming the transparent substrate 2, as shown in FIG.
A metal layer 34 having a high reflectance is formed over the entire back side 21b of the photoresist layer 35 on the surface of the metal layer 34.
form. The material for the metal layer 34 is preferably a material that can reflect incident light with high efficiency; for example, materials such as Al, Cr, Au, and Pt can be used.

After forming the photoresist layer 35 as described above, masking is performed so that the photoresist 1135 remains only at predetermined locations where light shielding portions are to be formed.

At this time, masking can be easily performed using the mark portion 33 as a reference.

Next, as shown in FIG. 2e, the photoresist layer 35 is exposed to light using the above-mentioned mask, and is developed to leave the photoresist layer 35 only at the portion where the light shielding portion is to be formed.

Subsequently, as shown in FIG. 2R, the metal layer 34 is etched away using the photoresist layer 35 as a mask, and then the photoresist layer 35 is removed to form a light shielding part 37.

As described above, a mark part is formed using the metal wiring layer of the element and the self-line, and a light shielding part is formed using this mark part as a reference. Therefore, the light shielding part can be formed very easily and with respect to the part to be light shielded. Can be formed with high precision.

In addition, in the method of manufacturing a liquid crystal display device, in addition to the method described above, the method for forming the light shielding portion may include, for example, using a transparent substrate
After forming a metal layer 34 by vapor deposition on the surface of the mark portion 32 formed on the back side 21b of the transparent substrate 21 by self-line, a positive type photoresist layer is further formed on top of the metal layer 34, and is exposed to light from the front side 21a of the transparent substrate 21. The photoresist layer may be left at a location where the light shielding portion 37 is to be formed in a self-aligned manner using the metal wiring layer 29, and the light shielding portion 37 may be formed using this as a mask. In this case, it is necessary to control the formation area of the light shielding part 37 by controlling the exposure conditions from the front side 21a of the transparent substrate 21.

Further, the metal layer 34 forming the light shielding part 37 may be formed by vapor deposition as in the above embodiment, but may also be formed by a method such as screen printing or laminating metal foil.

〔Effect of the invention〕

As is clear from the above description, the liquid crystal display device according to the present invention is formed with a self-line on the back side of one of the opposing transparent substrates, at a location facing the metal wiring layer constituting the element. Since the light-shielding part is formed based on the mark part, it is possible to cover the desired part of the element with high precision, and even though the aperture ratio is excellent, the light-shielding property is high, and high-quality LCD A display device can be provided.

In addition, a light shielding part is formed on the back side of the transparent substrate on which the elements are formed, and nothing is formed on the side of the transparent substrate facing each other with the liquid crystal in between, making it easy to bond opposing transparent substrates together. It can be carried out.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a liquid crystal display device to which the present invention is applied. FIGS. 2a to 2f are schematic sectional views sequentially showing a method of manufacturing a liquid crystal display device to which the present invention is applied. FIG. 3 is a schematic cross-sectional view showing an example of a conventional liquid crystal display device. 1.2.21... Transparent substrate 1a... Inner surface 1b... Outer surface 21a... Front side 21b... Back side 3.22... Element 4.37... Light shielding part 13 .29...Metal wiring layer 16.32...Mark portion 31...Polysilicon layer (semiconductor layer) Patent applicant
Sony Corporation Representative Patent Attorney Akira Koba (and two others) η Figure 2a Figure 2S Figure 2C Figure 3

Claims (2)

[Claims] (1) In a liquid crystal display device in which an element having at least a metal wiring layer is provided on the inner surface of one of the transparent substrates facing each other, the metal wiring layer and the self-line are provided on the outer surface of the one transparent substrate. A liquid crystal display device including a mark portion and a light shielding portion that blocks light from the element based on the mark portion. (2) A step of forming an element having a metal wiring layer on the front side of the transparent substrate and forming a semiconductor layer on the back side of the transparent substrate, and marking the semiconductor layer with the metal wiring layer of the element and self-line. 1. A method for manufacturing a liquid crystal display device, comprising: forming a light shielding portion with reference to the mark portion.