JP2000231113A - Reflective liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

[PROBLEMS] To provide a reflection type liquid crystal display device in which the uniformity of liquid crystal thickness and the flatness of a liquid crystal surface are improved and display unevenness and color shift do not occur, and a method of manufacturing the same. A semiconductor substrate, a driving circuit, a pixel layer, a transparent substrate, a liquid crystal, and a pixel region.
Is provided with a dummy pattern 40 in a peripheral region 41 of the pixel region, and the surface of the pixel region and the surface of the peripheral region are located substantially in the same plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device and a method of manufacturing the same, and more particularly, to a reflection type liquid crystal display device having improved uniformity of the thickness of a liquid crystal layer and flatness of a liquid crystal surface, and a method of manufacturing the same. About.

[0002]

2. Description of the Related Art In a device utilizing the optical characteristics of liquid crystal, such as a reflection type liquid crystal display device, the thickness of a liquid crystal layer must be uniform. In the case where a large number of pixels are aggregated, if the thickness of the liquid crystal layer is not uniform at the center and the periphery of the pixel area,
The electric field applied to the liquid crystal fluctuates, causing display unevenness. Also,
When the thickness of the liquid crystal layer is not uniform in the single pixel region, that is, when the pixel electrode is not flat but has irregularities, the reflectance is reduced and the brightness of the display device is reduced. When referring to the uniformity of the thickness of the liquid crystal layer, as described above, two types of uniformity, that is, the uniformity of the thickness over the entire area of the grouped pixels and the uniformity of the thickness within the single pixel area are considered. Becomes

Conventionally, in order to improve the uniformity of the thickness of the liquid crystal in a single pixel region, multilayer wiring on a semiconductor substrate is densely integrated and arranged, and a CMP (Chemical Mechanical Polishing) is provided in each layer.
A method of improving the flatness of a pixel electrode by performing shing (chemical mechanical polishing) has been proposed (JP-A-9-687).
No. 18).

In order to obtain a uniform cell gap over the entire pixel area, a glass or plastic sphere having a diameter of several μm is used as a spacer to form a spacer between the semiconductor substrate and the counter electrode. A method of dispersing a large number between the two is disclosed (Japanese Patent Laid-Open No.
-3318 publication).

However, in the case of an active matrix type silicon chip based reflective liquid crystal display device (hereinafter referred to as a "reflective liquid crystal display device on a semiconductor substrate") in which a drive circuit and a pixel layer are formed on a semiconductor substrate, a pixel is provided. Is about 15 μm, and an electric field is not correctly applied to a pixel layer on which a spacer having a diameter of several μm is placed, resulting in pixel defects. In order to solve this problem, a method has been proposed in which a pillar of an oxide film is built as a spacer using a general semiconductor manufacturing technique, and a pixel electrode is formed between the pillars (JP-A-8-248425). ).

However, this method also has a problem that the alignment process of the liquid crystal becomes defective or the column is lost during the alignment process because of the pillar of the oxide film as the spacer. Further, as another method, a method of blending a spacer into a panel seal has been disclosed (Japanese Patent Application Laid-Open No. 8-29728).
No. 6).

However, it is difficult to improve the uniformity of the cell gap over the entire pixel region only by the above-described method using the spacer.

In addition, there is another problem of deteriorating display quality, which is different from the above problem, in connection with the formation of a driving circuit and a pixel layer on a semiconductor substrate. That is, various films such as a silicon oxide film and a silicon nitride film are generally formed in the process of forming a circuit on a semiconductor substrate, and these films have some kind of compressive stress or tensile stress. These residual stresses have different magnitudes depending on manufacturing conditions. For this reason, the semiconductor element is not perfectly flat, but is somewhat curved. The prior art discloses a method of correcting a warp of a semiconductor substrate by bonding the semiconductor substrate to a flat, highly rigid, non-deformable substrate (Japanese Patent Laid-Open No. 9-22).
2596).

[0009]

However, according to the above method, the desired uniformity of the thickness of the liquid crystal portion and the flatness of the liquid crystal surface are not improved to a satisfactory level. The reason is mainly based on the following structure of the reflection type liquid crystal display device on the semiconductor substrate.

A drive circuit, a pixel layer, and a liquid crystal of a reflection type liquid crystal display device on a semiconductor substrate generally constitute a circuit as shown in FIG. That is, the liquid crystal display device includes a liquid crystal 112 for turning on and off a voltage for each single pixel 125 to adjust the amount of light to display light and dark, a capacitor 120 for applying the voltage, and a pixel transistor 119,
Further, a scanning circuit 160 having a horizontal shift register 154 and a vertical shift register 155 and a video signal line 164 and a selection line 165 for transmitting signals from these shift registers is provided.

A driving circuit in each single pixel has a multilayer structure shown in FIG. In FIG. 22, the liquid crystal is above the pixel electrode 110 made of aluminum, and external light is incident from above. Below the pixel electrode 110, an in-pixel light-shielding plate 108 made of aluminum, an aluminum wiring 106 forming a scanning circuit, a gate electrode 129 which is a part of a pixel transistor, and a storage capacitor 1
20 and a first polycrystalline silicon 103 and a second polycrystalline silicon 104.

If the above-described CMP is applied to the surface of the semiconductor substrate, it is possible to improve the uniformity in the single pixel region even if the driving circuit and the pixel layer are affected. However, as shown in FIG. 23, in the entire pixel region, the layer subjected to CMP becomes thinner in the peripheral region of the pixel region due to the influence of the drive circuit 123 and the pixel layer 124, and expands beyond a predetermined cell gap. Would. In FIG. 23, the configuration in the thickness direction is different between a pixel region 150 having a single pixel region 126 as a component and a peripheral region 141 thereof. That is, in the area where the panel seal 114 that seals the liquid crystal 112 at the periphery thereof and the area of the scanning circuit section 160, the storage capacity 1 provided in the pixel area 150 is provided.
The first polycrystalline silicon 103 and the second polycrystalline silicon 104 forming 20 are not provided. However, the pixel electrode 110 made of aluminum, the light-shielding plate 108 inside the pixel also made of aluminum, and the aluminum wiring 10 of the scanning circuit
6. Regardless of the planar shape of the interlayer insulating film 111, etc.,
Regarding the thickness, the pixel region and the peripheral region are formed in the same manner.

As described above, since the structure of the pixel region is different from that of the pixel region in the peripheral region, deformation and response to pressure applied to the surface and dynamic torsion are different. For this reason,
When CMP is performed, the polishing rate on the surface layer in the peripheral region is higher than that on the surface layer in the pixel region. As a result,
The thickness 135 of the liquid crystal 112 injected into the cell gap is:
The peripheral area 141 is compared with the pixel area 150.
The portion becomes thicker, and display unevenness appears in the pixel region and the peripheral region.

In the process of manufacturing a drive circuit for a semiconductor substrate, SOG (Spin On) is used to flatten an interlayer insulating film.
Glass) is commonly used. As shown in FIG. 24 which is a plan view of the circuit configuration on the semiconductor substrate, when the grouped pixel regions are interrupted, similar to the case where the CMP is performed,
The phenomenon that the thickness is reduced more in the peripheral region by the SOG occurs. In FIG. 24, a portion where the scanning circuit 144 and the panel seal 114 come into contact with each other are arranged in an area around the pixel area 150. In addition, wiring 141
And a pad 143 are arranged. FIG. 23 is a cross-sectional view at the position (XXIII-XXIII cross section) shown in FIG.

With respect to the above-described CMP and SOG, the thickness of the peripheral region where the drive circuit section is not provided is significantly different from that of the pixel region, and the thickness of the peripheral region is greatly reduced. That is, CMP and SOG improve the uniformity of the liquid crystal thickness and the flatness of the liquid crystal surface in the single pixel region, but rather deteriorate the liquid crystal thickness and the flatness of the liquid crystal surface over the entire aggregated pixel region. .

In the method of bonding the semiconductor substrate to a highly rigid substrate, when the semiconductor substrate is pressed with a uniform pressure,
The reaction force from the adhesive between the high-rigidity substrate and the semiconductor substrate also becomes uniform, and eventually the warpage of the semiconductor substrate is not corrected due to the balance between the action and the reaction. Therefore, when a highly rigid substrate is used, it is necessary to use more appropriate correction means. Further, in the case where the warpage of the semiconductor substrate is as shown in FIG. 25 or FIG. 26, even if a pressure for correction is applied to the periphery of the semiconductor substrate while preventing damage to the pixel region, the center of the semiconductor substrate is prevented. The portion does not become flat, and display unevenness is not eliminated. In FIG. 25, a semiconductor substrate 201 having a raised central portion is placed on a flat substrate 231 and an end of the semiconductor substrate is to be flattened by a transparent substrate 215 to which a panel seal 214 is attached. However, in the above-described warping mode, the bulge at the center cannot be eliminated even if the edge portion of the semiconductor substrate is pressed no matter how much.

In FIG. 26, the warp is wavy,
It is a climax in two places. Also in this case, even if the end portion of the semiconductor substrate 201 is pressed against the flat substrate 231 by the transparent substrate 215 to which the panel seal 214 is attached, the transparent substrate 215 does not become flat. In short, the warp configuration in which the pixel region is on the upper surface and the end is in contact with the flat substrate cannot correct the warpage of the semiconductor substrate without applying a force to the pixel region. However, applying force to the pixel area must be avoided because the pixel area may be damaged.

Therefore, an object of the present invention is to achieve uniformity of the thickness of the liquid crystal over the entire pixel region and uniformity of the single pixel region.
It is an object of the present invention to provide a reflection type liquid crystal display device in which the uniformity of the types is improved and the flatness of the liquid crystal surface is improved and there is no display unevenness and color shift, and a method of manufacturing the same.

[0019]

A reflection type liquid crystal display device according to a first aspect of the present invention comprises a semiconductor substrate, a drive circuit formed on a main surface of the semiconductor substrate, and a drive circuit formed on the drive circuit. A pixel layer, a transparent substrate facing the main surface of the semiconductor substrate, a liquid crystal injected between the transparent substrate and the semiconductor substrate, and a semiconductor substrate on which the pixel layer of the semiconductor substrate is defined in plan view. A region around the pixel region, which is a region, includes a dummy pattern in which the position in the height direction from the semiconductor substrate is provided in the same range as the driving circuit and the pixel layer, and the surface of the pixel region and the surface of the peripheral region are Are located substantially in the same plane.

Since the reflection type liquid crystal display device of the present invention has the dummy pattern as described above, the thin film of the same material is laminated on the liquid crystal side surface of the semiconductor substrate in the pixel region and the peripheral region. Therefore, the chemistry of the surface is not different between the pixel region and the peripheral region. However, if a dummy pattern is not provided in the peripheral region in the polishing process for ensuring the flatness of the surface, the degree of adhesion of the polisher member to the surface of the peripheral portion during polishing becomes higher than that of the pixel region, and the polishing of the peripheral region is performed. The rate increases. That is, when the dummy pattern is not provided, the surface of the peripheral region and the surface of the pixel region have different degrees of deformation and resilience against the pressing of the polisher member, and the adhesion of the polishing member is different. Changes.

The dummy pattern refers to a structure in which the mechanical response of the surface of the peripheral region to the polishing process is the same as that of the pixel region without participating in the operation of the reflective liquid crystal display device. Therefore, the laminated structure of the above-mentioned dummy pattern may not be the same as that of the pixel region.

By providing the dummy pattern in the peripheral region, the surfaces of both regions are formed so as to be located on the same plane. If the surfaces of both regions are in the same plane, the gap thickness of the cell gap becomes uniform, and therefore, the uniformity of the liquid crystal thickness is also improved, and a clear display is obtained by preventing display unevenness and color shift. Becomes possible.

In the above-mentioned dummy pattern of the reflection type liquid crystal display device of the present invention, the polishing rate of the surface layer of the peripheral region is equal to that of the pixel region in the polishing process for polishing the surface of the pixel region and the peripheral region of the pixel region. Is desirable.

As described above, in the dummy pattern provided in the peripheral region, the polishing rate of the surface layer in the peripheral region is made equal to the polishing rate of the surface layer in the pixel region when the surface layer is polished by CMP or SOG. . Therefore, the thickness of the semiconductor substrate can be made uniform over the peripheral region and the pixel region. As a result, the thickness of the liquid crystal can be made uniform not only in a single pixel region but also in the entire pixel region, and a clear image without display unevenness and color shift can be secured.

Note that the dummy pattern described above does not have to be the same thin film as the thin film stacked in the pixel region, as long as the polishing rate in the peripheral region is the same as that in the pixel region.

The dummy pattern in the reflection type liquid crystal display device of the present invention is formed by forming the same thin film as the thin film forming the driving circuit and the pixel layer in the pixel region at the same height and the same thickness. It is desirable that it be formed.

By forming the above dummy pattern, there is no difference between the peripheral region and the pixel region due to the material structure. As a result, in CMP or SOG processing, even if the surface layer is polished, the mechanical response to polishing does not differ between the peripheral portion and the pixel region. The chemical responsiveness was the same because the surface layer was originally formed as the same plane over the peripheral region and the pixel region. Therefore, by making the mechanical response of the peripheral region equal to that of the pixel region as described above, the degree of adhesion between the polished portion of the polishing apparatus and the surface becomes the same in both regions, and the polishing rate is also the same. can do. As a result, the semiconductor substrate can be made uniform over the pixel region and the peripheral region.

In the reflection type liquid crystal display device of the present invention, each thin film forming the dummy pattern is formed in the same manner as the step of forming each thin film forming the drive circuit and the pixel layer in the pixel area. It is also desirable that the film be formed by film formation.

By being formed in the same step,
The identity of the material and the like in the dummy pattern can be easily and reliably realized, and the mechanical response in the polishing process on the surface of the peripheral region and the surface of the pixel region can be made the same. As a result, it is possible to make the polishing rates in the CMP and SOG processes equal between the peripheral region and the pixel region without increasing the manufacturing cost.

The above-mentioned dummy pattern is viewed in plan,
The position in the height direction from the semiconductor substrate is formed in the same range as the drive circuit and the pixel layer in both the region where the scanning circuit portion is formed and the region where the panel seal that seals the liquid crystal at the periphery of the liquid crystal contacts. It is desirable to have been.

The peripheral portion of the pixel region includes a region where a scanning circuit is formed and a region where a panel seal is applied. In these regions, the polishing rate in the CMP or SOG processing is set to be the same as that of the pixel region. It is desirable to keep. Since the area where the scanning circuit is formed and the area where the panel seal is applied tend to be abnormally reduced in thickness, it is possible to efficiently prevent abnormally reduced thickness by making the polishing rate the same. As a result, it is possible to ensure the above-described high display quality and improvement in manufacturing yield.

A reflection type liquid crystal display device according to another aspect of the present invention provides a semiconductor substrate, a driving circuit formed on a main surface of the semiconductor substrate, a pixel layer formed on the driving circuit, A transparent substrate facing the main surface; a liquid crystal injected between the transparent substrate and the semiconductor substrate; and a holding substrate for fixing the semiconductor substrate and holding the semiconductor substrate flat. Including a residual stress distribution that is convexly curved to the substrate side in a state where the substrate and the holding substrate are removed.

As described above, when the transparent substrate and the substrate are removed, in a semiconductor substrate which warps to the holding substrate side, small unevenness is absorbed by this warping, and the flatness of the liquid crystal surface is reduced in the state of the finished product. It is easy to ensure a uniform liquid crystal thickness. In addition, since it is warped convexly toward the substrate side, when flattening is performed at the time of manufacturing, a force is applied to the periphery of the liquid crystal side surface (upper surface) and the center of the lower surface side without applying force to the fine structure portion of the pixel region. Can be added to correct the flatness, so that the pixel region is not damaged. As described above, since the holding substrate for holding the semiconductor substrate flat is arranged on the lower surface of the semiconductor substrate and integrated with the semiconductor substrate and the transparent substrate, the above-mentioned warpage is corrected to be flat.
Therefore, it is possible to improve the flatness of the liquid crystal surface and avoid the non-uniform thickness of the liquid crystal due to the unevenness of the semiconductor substrate without lowering the production yield.

According to another aspect of the present invention, there is provided a reflection type liquid crystal display device comprising: a semiconductor substrate; a driving circuit formed on a main surface of the semiconductor substrate; a pixel layer formed on the driving circuit; Opposite to the main surface, the semiconductor substrate includes a transparent substrate that fixes and holds the semiconductor substrate flat, and a liquid crystal injected between the transparent substrate and the semiconductor substrate. Then, it has a residual stress distribution that is concavely warped spherically on the high rigid transparent substrate side.

By making the transparent substrate facing the semiconductor substrate high in rigidity so that the semiconductor substrate can be held flat, the semiconductor substrate required for the reflection type liquid crystal display device in the above-mentioned other aspects can be reduced. A holding substrate for holding flat is unnecessary. Therefore, in addition to providing all the effects obtained by the reflection type liquid crystal display device of the other aspect described above, the need for the holding substrate is further eliminated, so that the manufacturing cost can be further reduced.

The above residual stress is desirably caused by a thin film formed on a semiconductor substrate.

In the step of forming the driving circuit and the pixel layer, if the stress giving the above-mentioned warp can be applied to the semiconductor substrate in addition to the original purpose such as interlayer insulation, the influence on the fine structure of the pixel region is small and it is easy. The above-mentioned reflection type liquid crystal display device can be manufactured.

The thin film is a thin film having a tensile stress distribution formed on the liquid crystal side of the semiconductor substrate, and desirably causes compression deformation on the liquid crystal side of the semiconductor substrate. Also,
Under a certain requirement, the thin film is a thin film having a compressive stress distribution formed on the lower surface of the semiconductor substrate opposite to the liquid crystal, and is preferably a thin film that causes tensile deformation on the lower surface side of the semiconductor substrate. .

By forming the thin film on a semiconductor substrate, the warpage can be easily imparted to the semiconductor substrate without enlarging the shape of the liquid crystal display device. The flatness of the surface and the uniform thickness of the liquid crystal can be ensured.

According to the method of manufacturing a reflection type liquid crystal display of the present invention, a step of making the lower surface of the semiconductor substrate convexly spherical with the pixel region side of the semiconductor substrate as the upper surface, and a step of correcting the warpage of the semiconductor substrate so as to be able to correct it. A holding substrate having high rigidity,
By sandwiching the semiconductor substrate with the convex side of the lower surface on the side of the holding substrate between the lower surface of the transparent substrate to which the panel seal that seals the liquid crystal is attached at the periphery of the liquid crystal and pressing down, the semiconductor substrate is flattened. Integrating the holding substrate, the semiconductor substrate, and the transparent substrate.

As described above, by warping the semiconductor substrate to the lower surface, small irregularities on the semiconductor substrate are absorbed to facilitate the correction, and the flatness is corrected only by applying a force to the periphery of the upper surface and the center of the lower surface. be able to. For this reason, since a force is not directly applied to the fine structure portion of the pixel region, it is possible to prevent the pixel region from being damaged due to the correction, which is a factor contributing to an improvement in yield. The warpage is corrected on the holding substrate, and the holding substrate, the semiconductor substrate, and the transparent substrate are integrated, so that a uniform liquid crystal thickness and a flat liquid crystal surface can be secured.

According to another method of manufacturing a reflection type liquid crystal display of the present invention, a step of making the lower surface of the semiconductor substrate convexly spherical with the pixel region side of the semiconductor substrate as the upper surface, and correcting the warpage of the semiconductor substrate. By sandwiching a semiconductor substrate with the lower convex surface facing the flat substrate between the lower surface of the transparent substrate having the panel seal of the rigidity as high as possible and the flat substrate, the semiconductor substrate is flattened. Integrating the transparent substrate and the semiconductor substrate.

In this method, the transparent substrate facing the main surface of the semiconductor substrate has a rigidity high enough to correct the warpage of the semiconductor substrate. No holding substrate is required. Therefore, in addition to the effects obtained by the above-described method of manufacturing a reflective liquid crystal display according to the present invention, it is possible to secure a reduction in manufacturing cost due to a reduction in weight of a finished product and a reduction in the number of parts.

In the above two methods for manufacturing a reflection type liquid crystal display of the present invention, forming the thin film having a tensile stress distribution on the upper surface side of the semiconductor substrate by forming the lower surface side of the semiconductor substrate convexly and spherically, Desirably, the compression is performed on the upper surface side. Also, in some cases, the lower surface side of the semiconductor substrate may be convexly warped in a spherical shape by forming a thin film having a compressive stress distribution on the lower surface side of the semiconductor substrate and subjecting the lower surface to tensile deformation. desirable.

It is very easy to generate the above-mentioned stress while forming a surface layer, an insulating film, etc. for the original insulating purpose. Therefore, the above-mentioned warpage can be easily generated, and no extra man-hour is required. As a result, it is possible to secure a uniform liquid crystal thickness and a flat liquid crystal surface without increasing the manufacturing cost.

[0046]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a plan view of a pixel region and the like formed on a semiconductor substrate of a reflection type liquid crystal display device according to Embodiment 1. Referring to FIG. 1, a pixel region 10 having a single pixel region 25 as a constituent is provided on a semiconductor substrate.
And a scanning circuit section 16 and a region where the panel seal 14 contacts (hereinafter simply referred to as “panel seal”). A peripheral region 41 including the panel seal and the scanning circuit portion is provided. Outside the panel seal, a pad 34 and a wiring 33 connecting the scanning circuit section 16 and the pad 34 are provided. In the present invention, the peripheral region 4
1 is characterized in that a dummy pattern is provided.

FIG. 2 shows the position (II-II) shown in FIG.
FIG. 2 is a cross-sectional view (a cross-section) (however, a scanning circuit unit 16 is not shown). The pixel region 10 having the single pixel region 25 as a component is made of the first polycrystalline silicon 3 and the second polycrystalline silicon 4 forming the capacitor 20, the aluminum wiring 6 forming the wiring of the scanning circuit, and aluminum. A light-shielding plate 8 in a pixel and a pixel electrode 9 made of aluminum are provided. The drive circuit section 23 includes a storage capacitor 20 and a pixel transistor 19, and the pixel layer 24 includes a pixel electrode 9, a surface layer 17.
including.

In the peripheral region 41 outside the pixel region, the dummy pattern 40 extends over the region where the scanning circuit portion and the panel seal 14 are in contact with each other, and is located at the same height position as the driving circuit portion and the pixel layer in the pixel region. Formed in a range. The dummy pattern 40 has a lower polycrystalline silicon 31 having the same composition and the same thickness as the first polycrystalline silicon 3, and an upper polycrystalline silicon 32 having the same composition and the same thickness as the second polycrystalline silicon 4.
A first aluminum layer 36 having the same composition and the same thickness as the aluminum wiring 6; a second aluminum layer 38 having the same composition and the same thickness as the intra-pixel light-shielding plate 8; The third
Aluminum layer 39 and interlayer insulating films 11, 12, 13 therebetween
(In FIG. 2, the interlayer insulating films 11 and 12 are not separately shown.) As compared with the cross-sectional configuration diagram of the conventional similar device shown in FIG. 23, in FIG. 2, in the peripheral region, each thin film forming the dummy pattern 40 is made of the same material as the thin film forming the driving circuit and the pixel layer. At the same height,
It is characterized in that it is formed with the same thickness.

The reflection type liquid crystal display device according to the first embodiment can be manufactured according to the steps shown in FIGS. 3 to 10 show only the configuration cross section of the pixel region. In the region around the pixel region, the above-described aluminum layers and interlayer insulating films are laminated under the same conditions as the pixel region to form a dummy pattern 40. ing.

First, as shown in FIG. 3, a field oxide film 2 as an isolation oxide film is provided on the main surface of a semiconductor substrate.
Next, as shown in FIG. 4, after forming a pixel transistor having a drain 27, a source 28 and a gate 29, an interlayer insulating film 11 is formed thereon and a contact hole is opened (FIG. 5). After the plug hole is filled with a plug conductive material to form a plug conductive portion 5, an aluminum wiring 6 forming a scanning circuit is formed on the plug conductive portion 5 and the interlayer insulating film 11 as shown in FIG. Is provided.

A second interlayer insulating film 12 is formed so as to cover the aluminum wiring 6 (FIG. 7). As shown in FIG. 8, a pixel light shielding plate 8 made of aluminum is formed on the second interlayer insulating film. Form. A third interlayer insulating film 13 is formed so as to cover the intra-pixel light-shielding plate 8, and a second contact hole is opened (FIG. 9). After forming a second plug conductive portion or the like filling the second contact hole, a pixel electrode 9 made of aluminum is formed thereon, and a surface layer 17 is further formed as shown in FIG.
To form

Next, a polyimide solution or the like is applied thereon, dried and baked, and then subjected to a rubbing treatment to provide an alignment layer for determining the alignment of the liquid crystal (the alignment layer is not shown).

As described first, FIGS.
At the opportunity of forming each thin film in the manufacturing process shown in FIG. 7, a thin film of the same material and of the same thickness is formed at the same height position in the peripheral region, and the dummy pattern 40 is formed.

Since the surface layer is formed of a common thin film in the peripheral region and the pixel region, it is chemically identical. However, since both regions have different internal structures, unless a dummy pattern is provided in the peripheral region,
The mechanical behavior for the application of external stress is different. The mechanical behavior causes a difference in the polishing rate in actual CMP or SOG processing. The reason for this is that the deformation and repulsion of the surface with respect to the pressing and rotation sliding by the polishing unit of the polishing apparatus change, and the adhesion between the polishing unit and the surface changes. By providing a dummy pattern in the peripheral region to eliminate the difference in mechanical behavior between the two regions, it is possible to eliminate the difference in polishing rate in CMP or SOG processing.

As a result, in FIG. 2, the liquid crystal 21 injected between the transparent substrate 15 including the electrode 18 and the semiconductor substrate is formed.
Has a uniform thickness 22 and does not cause display unevenness or color shift. Since the dummy pattern 40 is also formed so as to overlap with the area which comes into contact with the panel seal 14 included in the peripheral area 41, it is possible to prevent the thickness of the semiconductor substrate from being abnormally reduced in the area where the panel seal comes into contact.
As a result, the gap 22 between the transparent substrate 15 having the electrode 18 and the semiconductor substrate can be made uniform, and high quality liquid crystal display can be secured.

(Embodiment 2) Next, Embodiment 2 will be described.

The drive circuit provided on the main surface of the semiconductor substrate is manufactured by the manufacturing steps shown in FIGS. In the second embodiment, the dummy pattern shown in the first embodiment may or may not be provided. With the surface on which the drive circuit and the pixel layer are formed as the upper surface, during the manufacturing process, for example, at the time of forming an oxide film as an interlayer insulating film, the residual stress distribution in the oxide film is formed as tensile stress, and the semiconductor is formed. Compressive deformation is caused on the upper surface of the substrate to warp the semiconductor substrate to the lower surface.

To form a thin film in which tensile residual stress is distributed, for example, when the semiconductor substrate is a silicon substrate,
A thin film of silicon oxynitride SiO _x N _y is formed by CVD (Chemical Vapor Deposition), and the ratio of the number of nitrogen atoms to the sum of the number of oxygen atoms and the number of nitrogen atoms, ie,
This can be realized by setting n _N / (n _N + n _O ) to 0.1 or more. As the above ratio increases, the magnitude of the tensile stress increases, and reaches its maximum in the extreme case, that is, when the SiN ₂ film is formed.

As the thin film that warps the semiconductor substrate so as to protrude downward, it may be desirable to form a thin film that generates a compressive stress on the lower surface side of the semiconductor substrate and tensile-deform the lower surface of the semiconductor substrate. In such a case, for example, a thin film of silicon oxynitride SiO _x N _y is formed on the lower surface of the silicon substrate, and n _N / (n _N + n _O ) is set to less than 0.1. Usually, an oxide film SiO ₂ is formed. The oxide film has a compressive stress distribution, and a tensile deformation occurs on the surface of the semiconductor substrate on which the oxide film is formed, in balance with the compressive stress in the oxide film. The magnitude of the compressive stress in the oxide film SiO ₂ is
The higher the O ₂ density, the higher the O ₂ density. When the oxide film SiO ₂ is formed by CVD, the compression stress can be increased by increasing the temperature at the time of formation.

Next, as shown in FIG. 11, a semiconductor substrate 44 is placed on a ceramic substrate 43 having sufficient rigidity to correct the warpage of the semiconductor substrate, and a transparent glass substrate 46 is placed on the semiconductor substrate 44. A panel seal 45 attached with an adhesive compounded with a spacer is pressed. If the adhesive has too much fluidity, the warp cannot be corrected by pressing, and if the fluidity is too small, it will be difficult to adjust the adhesive to an appropriate cell gap. It is desirable to use an epoxy adhesive as this adhesive. At this time, the position where the force is applied to the semiconductor substrate is around the edge of the upper surface of the semiconductor substrate and the center of the lower surface. Thereafter, the glass substrate 46, the semiconductor substrate 44, and the ceramic substrate 43 are integrated while correcting the warpage of the semiconductor substrate 44. Finally, liquid crystal is injected into the cell gap to complete the liquid crystal display. Since the direction of warpage of the semiconductor substrate is determined in advance, it can be easily corrected, and an optically flat element can be manufactured.

In the above manufacturing method, the semiconductor substrate is warped downwardly convex, so that a small warp is absorbed by the downwardly convex warp, thereby facilitating flatness correction. In addition, since flatness correction is performed by applying a force to the edge of the upper surface and the center of the lower surface, the correction can be performed without applying a force to the portion where the fine structure of the pixel region is formed, and damage to the pixel region due to the correction can be performed. It is possible to prevent occurrence.

Third Embodiment Next, a third embodiment will be described.

As in the second embodiment, the drive circuit and the pixel layer on the semiconductor substrate are manufactured by the manufacturing steps shown in FIGS. Further, the semiconductor substrate provided with the driving circuit and the pixel layer is warped convexly on the lower surface as shown in FIG. Next, as shown in FIG.
Is placed on a flat substrate 53, and a glass substrate 56 having sufficiently high rigidity to correct the warpage of the semiconductor substrate from above.
To which the panel seal 55 is attached. At this time, the points where the force is applied to the semiconductor substrate are the peripheral portion of the upper surface and the center of the lower surface. The glass substrate 56 and the semiconductor substrate 54 are integrated while applying a force as described above to correct the warpage of the semiconductor substrate. The semiconductor substrate and the glass substrate need to be electrically connected. Solder bumps 58 are attached to the upper surface of the semiconductor substrate, and the tips of the solder bumps are fixed to the glass substrate during the integration.

After the liquid crystal 59 is injected into the cell gap, the integrated liquid crystal display device is removed from the flat substrate 53, and the process is completed. As shown in FIG. 20, the glass substrate is provided with leads 59 for connecting to the outside of the liquid crystal display device.
And a solder bump pad 60 for electrically connecting the semiconductor substrate and the glass substrate.

In the above-described manufacturing method, the semiconductor substrate is warped downward so that the small warp is absorbed by the downward warp. In addition, since flatness correction is performed by applying a force to the edge of the upper surface and the center of the lower surface, the correction can be performed without applying a force to the portion where the fine structure of the pixel region is formed, and damage to the pixel region due to the correction can be performed. It is possible to prevent occurrence.

Further, by employing the above-mentioned reflection type liquid crystal display device, the thickness of the liquid crystal portion is not uniform due to the warpage of the semiconductor substrate and the liquid crystal surface is not used without using a highly rigid holding substrate other than the glass substrate. Flatness defects can be avoided.
As a result, it is possible to prevent the occurrence of display unevenness after reducing the number of parts, and to realize a clear image without color stain.

It should be noted that the embodiment disclosed this time is an example in all respects and is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0069]

According to the first aspect of the present invention, the thickness of the liquid crystal layer becomes uniform at the center and the periphery of the pixel region, and the display unevenness caused by the electric field applied to the liquid crystal fluctuating from place to place is eliminated. . For this reason, a clear image without color stain around the screen can be realized. Further, since a flat semiconductor substrate can be manufactured, the yield can be improved and the manufacturing cost can be reduced.

According to another aspect of the present invention, it is possible to eliminate unevenness in the thickness of the liquid crystal layer and poor flatness of the liquid crystal surface due to the warpage of the semiconductor substrate, thereby realizing a clear image and eliminating defective products during assembly and manufacture. Thus, the cost can be reduced.

According to still another aspect of the present invention, the above-mentioned defects caused by the warpage of the semiconductor substrate can be eliminated while reducing the number of components in the assembling process, and the assembling and manufacturing costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor substrate according to a first embodiment;

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a diagram showing a first manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 4 is a diagram showing a second manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 5 is a diagram showing a third manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 6 is a diagram showing a fourth manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 7 is a diagram showing a fifth manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 8 is a diagram showing a sixth manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 9 is a diagram showing a seventh manufacturing step of the semiconductor substrate of the first embodiment.

FIG. 10 is a diagram illustrating a configuration of a semiconductor substrate according to the first embodiment;

FIG. 11 is a diagram illustrating a first manufacturing step of the liquid crystal display device of the second embodiment.

FIG. 12 is a diagram illustrating a second manufacturing step of the liquid crystal display device of the second embodiment.

FIG. 13 is a diagram illustrating a third manufacturing step of the liquid crystal display device of the second embodiment.

FIG. 14 is a diagram illustrating a configuration of a liquid crystal display device according to a second embodiment.

FIG. 15 is a diagram illustrating a first manufacturing step of the liquid crystal display device of the third embodiment.

FIG. 16 is a diagram illustrating a second manufacturing step of the liquid crystal display device of the third embodiment.

FIG. 17 is a diagram illustrating a third manufacturing step of the liquid crystal display device of the third embodiment.

FIG. 18 is a diagram illustrating a fourth manufacturing step of the liquid crystal display device of the third embodiment.

FIG. 19 is a diagram illustrating a configuration of a liquid crystal display device of Embodiment 3.

20 illustrates an appearance of a liquid crystal display device according to Embodiment 3. FIG.

FIG. 21 is a diagram illustrating a circuit configuration of a general liquid crystal display device.

FIG. 22 is a diagram illustrating a three-dimensional configuration of a circuit of a general liquid crystal display device.

FIG. 23 is a configuration sectional view of a conventional liquid crystal display device.
(It is XXIII-XXIII sectional drawing of FIG. 24.)

FIG. 24 is a diagram showing a circuit configuration of a conventional semiconductor substrate.

FIG. 25 is a view showing warpage of a semiconductor substrate of a conventional liquid crystal display device.

FIG. 26 is a view showing another warpage of the semiconductor substrate of the conventional liquid crystal display device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 semiconductor substrate, 2 field oxide film, 3 first polycrystalline silicon, 4 second polycrystalline silicon, 6 aluminum wiring, 8 light shielding plate in pixel, 9 pixel electrode, 10 pixel region, 11 interlayer insulating film, 12 interlayer insulating film , 13 interlayer insulating film, 14 panel seal, 15 transparent substrate, 16
Scanning circuit section, 17 surface layer, 18 counter electrode, 19 pixel transistor, 20 storage capacity, 21 wiring, 2
2 cell gap, 23 drive circuit section, 24 pixel layers,
25 single pixel area, 27 drain, 28 source,
29 gate, 31 lower polycrystalline silicon, 32 upper polycrystalline silicon, 33 wiring, 34 pad, 36 first aluminum layer, 38 second aluminum layer, 39 third aluminum layer, 40 dummy pattern, 43 holding substrate, 44 semiconductor substrate , 45 panel seal, 46 transparent substrate, 47
Liquid crystal, 53 flat substrate, 54 semiconductor substrate, 55 panel seal, 56 high rigid transparent substrate, 58 solder bump, 59 liquid crystal, 60 bump pad.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Sekiguchi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Junichi Fujino 2-3-2 Marunouchi 3-chome, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd. F term (reference) 2H092 GA49 GA59 JA23 JB07 JB13 KA03 KA16 KA18 KB14 KB23 MA13 MA17 NA04 NA15 NA19 NA25 NA27 PA12 QA07

Claims (14)

[Claims] A semiconductor substrate; a driving circuit formed on a main surface of the semiconductor substrate; a pixel layer formed on the driving circuit; and a transparent substrate facing the main surface of the semiconductor substrate. A liquid crystal injected between the transparent substrate and the semiconductor substrate; and a region around a pixel region, which is a region on the semiconductor substrate defined by viewing the pixel layer of the semiconductor substrate in a plan view. A position in a height direction from the semiconductor substrate is provided in the same range as the driving circuit and the pixel layer; and a dummy pattern is provided, and a surface of the pixel region and a surface of the peripheral region are substantially in the same plane. Located, reflective liquid crystal display device. 2. The polishing method according to claim 1, wherein in the polishing process of polishing the surfaces of the pixel region and the peripheral region of the pixel region, a polishing rate of a surface layer of the peripheral region is made equal to that of the pixel region. Item 2. The reflective liquid crystal display device according to item 1. 3. The dummy pattern is formed by forming the same thin film as the thin film forming the driving circuit and the pixel layer in the pixel region at the same height and the same thickness. Item 3. The reflective liquid crystal display device according to item 1 or 2. 4. The thin film forming the dummy pattern is formed by forming a film also in the peripheral region in the same step as forming the thin film forming the drive circuit and the pixel layer in the pixel region. The reflective liquid crystal display device according to claim 3, wherein: 5. The method according to claim 1, wherein the dummy pattern is
In both the region where the scanning circuit portion is formed and the region where the panel seal that seals the liquid crystal abuts on the periphery of the liquid crystal, the position in the height direction from the semiconductor substrate is in the same range as the driving circuit and the pixel layer. The reflection type liquid crystal display device according to claim 1, wherein the reflection type liquid crystal display device is formed. 6. A semiconductor substrate, a driving circuit formed on a main surface of the semiconductor substrate, a pixel layer formed on the driving circuit, a transparent substrate facing the main surface of the semiconductor substrate, A reflective liquid crystal display device comprising: a liquid crystal injected between the transparent substrate and the semiconductor substrate; and a holding substrate for fixing the semiconductor substrate and holding the semiconductor substrate flat. A reflection type liquid crystal display device, wherein the substrate includes a residual stress distribution that is convexly curved to the holding substrate side in a spherical shape when the transparent substrate and the holding substrate are removed. 7. A semiconductor substrate, a driving circuit formed on a main surface of the semiconductor substrate, a pixel layer formed on the driving circuit, and the semiconductor substrate facing the main surface of the semiconductor substrate And a liquid crystal injected between the transparent substrate and the semiconductor substrate, wherein the transparent substrate is removed from the semiconductor substrate. In the state
A reflective liquid crystal display device including a residual stress distribution that is concavely warped spherically toward the transparent substrate. 8. The reflection type liquid crystal display device according to claim 6, wherein the remaining stress is caused by a thin film formed on a semiconductor substrate. 9. The reflective liquid crystal according to claim 8, wherein the thin film has a tensile stress distribution, is formed on the liquid crystal side of the semiconductor substrate, and causes a compression deformation on a surface of the semiconductor substrate on the liquid crystal side. Display device. 10. The reflective liquid crystal display according to claim 8, wherein the thin film has a compressive stress distribution and is formed on the lower surface of the semiconductor substrate opposite to the liquid crystal to cause tensile deformation on the lower surface. apparatus. 11. A semiconductor substrate having a pixel layer side as an upper surface,
A step of warping the semiconductor substrate to the lower surface side in a spherical shape to be convex, a holding substrate having a rigidity high enough to correct the warpage of the semiconductor substrate, and a panel seal for sealing the liquid crystal at a peripheral portion of the liquid crystal are attached. By sandwiching and pressing the semiconductor substrate with the convex side of the lower surface facing the holding substrate between the transparent substrate and the lower surface of the transparent substrate, the semiconductor substrate is planarized, and the holding substrate, the semiconductor substrate, and the transparent substrate are flattened. A method of manufacturing a reflection-type liquid crystal display device, comprising a step of integrating the substrate with a substrate. 12. A step of making the semiconductor substrate convex to the lower surface side in a spherical shape with the pixel layer side of the semiconductor substrate as an upper surface, and a transparent substrate having a rigidity high enough to correct the warpage of the semiconductor substrate. The semiconductor substrate having a convex surface of the lower surface facing the flat substrate is sandwiched and pressed between a lower surface on which a panel seal for sealing the liquid crystal is attached at a peripheral portion of the liquid crystal and a flat substrate, thereby pressing the semiconductor. Flattening the substrate to integrate the transparent substrate and the semiconductor substrate. 13. The method according to claim 13, wherein the semiconductor substrate is convexly curved to the lower surface side in a spherical shape by forming a thin film having a tensile stress distribution on the upper surface side of the semiconductor substrate and compressing and deforming the upper surface side. A method for manufacturing a reflective liquid crystal display device according to claim 11. 14. The method according to claim 14, wherein the semiconductor substrate is convexly curved to the lower surface side in a spherical shape by forming a thin film having a compressive stress distribution on the lower surface side of the semiconductor substrate and tensile-deforming the lower surface side. Item 13. The method for manufacturing a reflective liquid crystal display device according to item 11 or 12.