JP4438379B2 - Electro-optical device and electronic apparatus - Google Patents

Description

  The present invention relates to an electro-optical device, a manufacturing method thereof, and an electronic apparatus.

  A liquid crystal device, which is one of electro-optical devices, is frequently used not only as a direct-view display but also as a light modulation means (light valve) of, for example, a projection display device. The resolution of liquid crystal devices has been increasing year by year. Especially when used as a light valve in a projection display device, the image on the light valve is enlarged and the demand for higher resolution is becoming stricter. Yes. Therefore, if the resolution is increased while maintaining the aperture ratio in order to ensure a bright image, the wiring width and the area occupied by the thin film transistor (hereinafter abbreviated as TFT) are inevitably reduced. Must. As a result, for example, in an active matrix substrate, it is necessary to reduce the diameter of contact holes for connecting data lines and scanning lines to TFTs. On the other hand, a liquid crystal device in which a driving circuit for driving a pixel switching TFT is built on a substrate has been conventionally provided. In this type of liquid crystal device, there is a requirement that a high-performance drive circuit must be formed in a limited peripheral region outside the display region, and there are TFTs, wiring, and contact holes that constitute the drive circuit in the peripheral circuit region. There is a growing need for miniaturization.

However, when the contact hole is reduced in size, if an attempt is made to form wiring with aluminum (Al) or the like, the Al film is not formed with good coverage on the bottom and side surfaces of the contact hole, so that the contact resistance increases or is severe. May cause a disconnection failure. In order to solve this problem, for example, in a semiconductor manufacturing process such as LSI, a technique of filling the inside of a contact hole with tungsten and forming an upper wiring layer thereon, a so-called tungsten plug technique is used (for example, patent document). 1). While aluminum formed by sputtering is inferior in step coverage, tungsten can be formed by CVD, and a film having excellent step coverage can be formed.
JP-A-6-342792

However, when a tungsten plug is used, it is necessary to form an adhesion layer under the tungsten layer. The reason is that although the tungsten layer is excellent in step coverage, the adhesion to the insulating layer is poor due to the difference in internal stress at the interface between the different material layers. Further, in order to protect the underlying conductor layer from a metal fluoride gas such as WF ₆ which is a raw material gas when forming the tungsten layer, it is also necessary to improve the barrier property. From the above, it is necessary to form a laminated film of titanium (Ti) / titanium nitride (TiN) or a laminated film of titanium (Ti) / titanium oxynitride (TiON) under the tungsten layer. Therefore, many steps are required only by forming the tungsten plug, and the manufacturing process becomes complicated. Therefore, it has been proposed to use a plug made of polycrystalline silicon (hereinafter referred to as a polysilicon plug in this specification) that does not have the above-mentioned problems such as adhesion.

7 and 8 are process cross-sectional views illustrating an example of a method for manufacturing a TFT having a contact portion using a polysilicon plug.
First, as shown in FIG. 7A, an N-channel TFT 61 and a P-channel TFT 62 are formed on a substrate 60 by a conventional general method. In the case of an active matrix substrate used for an electro-optical device such as a liquid crystal device, generally, a pixel switching TFT in a display region is an N-channel TFT, and a circuit forming TFT in a peripheral circuit region is an N-channel TFT and a P-channel TFT. The complementary TFT is generally used. Therefore, in FIG. 7 and FIG. 8, both TFTs are shown, and an N-channel TFT 61 is shown on the left side and a P-channel TFT 62 is shown on the right side.

Next, as shown in FIG. 7B, after an interlayer insulating film 63 covering the TFTs 61 and 62 is formed, the source regions 61s and 62s and drain regions of the TFTs 61 and 62 are penetrated through the interlayer insulating film 63. Contact holes 64 reaching 61d and 62d are formed.
Next, as shown in FIG. 7C, a polysilicon film 65 into which a P-type impurity such as boron is introduced is formed on the entire surface of the substrate 60 including the inside of the contact hole 64.
Next, as shown in FIG. 8D, the polysilicon plug 66 is formed by leaving the polysilicon only in the contact hole 64 on the P-channel TFT 62 side by using the planarization technique and the photolithography technique, and the remaining polysilicon is formed. All of the silicon film 65 is removed.

Next, as shown in FIG. 8E, a polysilicon film 67 doped with an N-type impurity such as phosphorus is formed on the entire surface of the substrate 60 including the inside of the contact hole 64 on the N-channel TFT 61 side.
Next, as shown in FIG. 8F, the polysilicon film 67 on the upper part of the interlayer insulating film 63 is removed by using an etch back technique or the like, and polysilicon is formed inside the contact hole 64 on the N channel TFT 61 side. Then, the polysilicon plug 68 is formed.
Finally, as shown in FIG. 8G, a metal film such as aluminum is formed and patterned by using a photolithographic technique, whereby the metal wiring 69 is formed on the polysilicon plugs 66 and 68 of the TFTs 61 and 62, respectively. Form.

However, the above manufacturing method has a problem that a large number of steps are required to form the polysilicon plug. When a polysilicon plug is used on a TFT, it has the advantage that the plug can be formed directly on the semiconductor layer of the TFT without forming an adhesion layer as in the case of a tungsten plug, but this simplifies the contact formation process. Could not be realized.
Here, the problem has been described in the case where the source / drain regions of the TFT and the metal wiring are connected using the polysilicon plug. However, the upper wiring may be integrally formed with the polysilicon film embedded in the contact hole. In that case, we had similar problems.

  The present invention has been made to solve the above-described problems, and can simplify the manufacturing process and provide an electro-optical device including a TFT having a structure capable of miniaturizing a contact hole, and the manufacturing thereof. It aims to provide a method. It is another object of the present invention to provide an electronic apparatus that can realize a high-resolution display including the electro-optical device.

  In order to solve the above-described problems, an electro-optical device according to the present invention includes an electro-optical device in which a display region having a plurality of pixel switching TFTs and a peripheral circuit region having a plurality of circuit forming TFTs are provided on a substrate. In the device, the pixel switching TFT in the display region and the circuit forming TFT in the peripheral circuit region are all the same conductivity type TFT, and the electrical connection of the source region or the drain region of each TFT is performed. A contact hole is provided, and polycrystalline silicon having the same conductivity type as that of the source region and the drain region of the TFT is embedded in the contact hole.

  In a conventional electro-optical device having a peripheral drive circuit, a complementary TFT is usually formed on a substrate. Therefore, a contact portion in which P-type polysilicon is embedded and N-type polysilicon are embedded in a contact hole. I had to make a separate contact part. That is, unless P-type polysilicon is used for the contact portion of the P-channel TFT and N-type polysilicon is used for the contact portion of the N-channel TFT, a PN junction (diode junction) can be formed in the contact portion. This is because normal contact characteristics cannot be obtained. Therefore, many steps are required to form both contact portions. On the other hand, in the electro-optical device of the present invention, the pixel switching TFT in the display area and the circuit forming TFT in the peripheral circuit area are all the same conductivity type TFT. That is, the TFT in the display area and the TFT in the peripheral circuit area are all unified as either a P-channel TFT or an N-channel TFT. For this reason, it is only necessary to form either P-type or N-type polysilicon corresponding to the contact portion, and the contact portion forming process can be simplified.

Furthermore, an upper conductive layer is provided on the upper layer side of each TFT, and the source region or drain region and the upper conductive layer are electrically connected via a contact plug made of polycrystalline silicon embedded in the contact hole. It is also possible to have a configuration in which they are connected.
In this case, since the material other than the polycrystalline silicon constituting the contact plug can be used as the upper conductive layer, the material of the upper conductive layer can be selected according to the characteristics required depending on the use of the upper conductive layer and the like. .

Alternatively, the upper conductive layer may be integrally formed with polycrystalline silicon embedded in the contact hole.
In such an active matrix substrate, in addition to the above switching elements, resistors, capacitive elements, various wirings and the like are formed on the substrate, and polycrystalline silicon is often used as these constituent elements. In that case, according to the above-described method, since the polycrystalline silicon becomes the upper conductive layer as the above-described component as it is, it is not necessary to add a new process, and the configuration of the present invention is realized by a simple manufacturing process. be able to.

The electro-optical device of the present invention is particularly effective when the thickness of the active layer constituting each TFT is 100 nm or less.
When the active layer thickness of a TFT is as thin as 100 nm or less, in a general contact formation using aluminum, the silicon layer of the originally thin source / drain contact portion is consumed by the reaction between silicon and aluminum or the underlying metal layer. The contact resistance may increase remarkably due to such a phenomenon. In order to counter this problem, it is common practice to form a barrier metal layer that protects the silicon layer in the contact portion. Another idea is to lower the contact resistance by epitaxially growing the silicon layer in the contact portion and increasing the thickness of this portion. However, these methods lead to an increase in the number of steps compared to the current manufacturing process. Therefore, from the viewpoint of avoiding the problem of increase in contact resistance, it is preferable to make contact using silicon which is the same material as the active layer as in the present invention. The above problem is more remarkable when the active layer thickness is 50 nm or less.

  As the active layer constituting each TFT, any of polycrystalline silicon and amorphous silicon can be used. However, if it is composed of single crystal silicon, a higher performance TFT can be obtained.

The substrate is an active matrix substrate having a plurality of data lines and a plurality of scanning lines provided so as to cross each other, and the peripheral circuit region includes a data line driving circuit for driving the data lines and the scanning lines. In the case of including a scanning line driving circuit to be driven, it is preferable that an external complementary driving element is electrically connected to the data line driving circuit.
The electro-optical device of the present invention uses only a single-channel TFT. However, a peripheral TFT, particularly a data line driver, is a complementary TFT due to circumstances in which high performance of the circuit is required such as improvement of driving capability. There is a demand to use it. In that case, as described above, an external complementary driving element may be electrically connected to the data line driving circuit. With this configuration, a data line driving circuit having sufficient performance can be realized by selecting an appropriate complementary driving element.

  Further, there is an effect of reducing power consumption by using a complementary driving element. However, even if an external complementary drive element is not used in the device configuration of the present invention, the power of the liquid crystal panel is higher than that of the projection light source in applications such as a liquid crystal panel for a projection display device. Since it is very small, increasing it slightly is not a problem.

The electro-optical device manufacturing method of the present invention is a method for manufacturing an electro-optical device in which a display region having a plurality of pixel switching TFTs and a peripheral circuit region having a plurality of circuit forming TFTs are provided on a substrate. A step of forming a plurality of TFTs all having the same conductivity type in the display region and the peripheral circuit region; and an interlayer insulating film covering the TFT is formed, and then the TFTs are formed on the interlayer insulating film. Forming a contact hole communicating with each of the source region and the drain region, and forming a polycrystalline silicon film having the same conductivity type as the source region and the drain region of the TFT on the entire surface of the substrate including the inside of the contact hole. It is characterized by that.
According to the method for manufacturing an electro-optical device of the present invention, as described above, either P-type or N-type polycrystalline silicon may be formed as a contact portion connected to the source region or drain region of the TFT. Compared with the conventional manufacturing method, the formation process of the contact portion can be simplified.

  Further, corresponding to the above two structures, a portion of the polycrystalline silicon film located above the interlayer insulating film is removed to leave the polycrystalline silicon film inside the contact hole. The method may further include a step of forming a contact plug made of polycrystalline silicon having the same conductivity type as the TFT, and a step of forming an upper wiring layer on the contact plug. Alternatively, the method may further include a step of forming an upper conductive layer by patterning a polycrystalline silicon film formed on the entire surface of the substrate.

An electronic apparatus according to the present invention includes the electro-optical device according to the present invention.
By providing the electro-optical device of the present invention, an electronic apparatus having a display unit with high resolution and low cost can be realized.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In this embodiment, an example of an active matrix type transmissive liquid crystal device (liquid crystal light valve) used for a light valve of a projection display device will be described.
FIG. 1 is a plan view of the liquid crystal device (electro-optical device) according to the present embodiment as viewed from the counter substrate side together with each component, and FIG. 2 is a cross-sectional view taken along the line HH ′ of FIG. FIG. 3 is a sectional view in which only the TFT portion is taken out and enlarged, and FIG. 4 is a sectional view for explaining a manufacturing method of the TFT, particularly a method for forming a contact portion. In each drawing used in the following description, the scale is different for each layer and each member so that each layer and each member can be recognized on the drawing.

  As shown in FIG. 1 and FIG. 2, in the liquid crystal device 100 of the present embodiment, the TFT array substrate 10 (active matrix substrate) and the counter substrate 20 are bonded together by a sealing material 52 and partitioned by the sealing material 52. A liquid crystal layer 50 is sealed in the region. A light shielding film (peripheral parting) 53 made of a light shielding material is formed in a region inside the region where the sealing material 52 is formed. In the peripheral circuit area outside the sealing material 52, a data line driving circuit 201 and an external circuit mounting terminal 202 are formed along one side of the TFT array substrate 10, and scanning lines are formed along two sides adjacent to the one side. A drive circuit 104 is formed. On the remaining side of the TFT array substrate 10, a plurality of wirings 105 are provided for connecting between the scanning line driving circuits 104 provided on both sides of the display area. In addition, an inter-substrate conductive material 106 for providing electrical continuity between the TFT array substrate 10 and the counter substrate 20 is disposed at a corner portion of the counter substrate 20.

  In this embodiment, instead of forming the data line driving circuit 201 on the TFT array substrate 10, for example, a COF (Chip On Flexible cable) substrate on which a complementary driving LSI is mounted and the TFT array substrate 10 are mounted. A terminal group formed in the peripheral portion of the electrode may be electrically and mechanically connected via an anisotropic conductive film. That is, the data line driving circuit 201 may be shared by an external complementary driving LSI.

  In the display region of the liquid crystal device 100 having such a structure, a plurality of data lines and a plurality of scanning lines are formed so as to intersect each other, and a plurality of pixels are arranged in a matrix. In each of these pixels, a pixel electrode and a pixel switching TFT are formed, a data line for supplying an image signal is electrically connected to a source region of the pixel switching TFT, and the pixel electrode is used for pixel switching. It is electrically connected to the drain region of the TFT. On the other hand, a scanning line for supplying a scanning signal is electrically connected to the gate electrode of the pixel switching TFT. In this embodiment, the pixel switching TFTs in the display area and the circuit forming TFTs in the peripheral circuit area including the data line driving circuit 201 and the scanning line driving circuit 104 are all composed of the same conductivity type TFT. Yes. Specifically, all TFTs on the TFT array substrate are unified to N-channel TFTs.

  FIG. 3 shows a pixel switching TFT 30 on the TFT array substrate 10 as a representative. A base insulating film 12 is formed on the TFT array substrate 10, and a pixel switching TFT 30 (hereinafter simply referred to as “TFT”) that controls switching of each pixel electrode is provided thereon. The TFT 30 has an LDD (Lightly Doped Drain) structure, and includes a scanning line (gate electrode) 3a, a channel region 1a ′ of a semiconductor layer (active layer) 1a in which a channel is formed by an electric field from the scanning line 3a, A gate insulating film 2 that insulates the scanning line 3a from the semiconductor layer 1a, a data line 303, a low concentration source region 1b and a low concentration drain region 1c of the semiconductor layer 1a, a high concentration source region 1d, and a high concentration drain region 1e. Yes. The semiconductor layer may be any of single crystal silicon, polycrystalline silicon, and amorphous silicon, but single crystal silicon is desirable in order to obtain a TFT with high driving capability. .

  The TFT 30 is covered with a first interlayer insulating film 311, and contact holes 82 and 83 are formed in the first interlayer insulating film. A capacitor electrode 302 (upper conductive layer) constituting a storage capacitor is electrically connected to the high concentration drain region 1e through a contact hole 83. Further, the data line 303 (upper conductive layer) is electrically connected to the high concentration source region 1d through the contact hole 82. In the present embodiment, the capacitor electrode 302 and the data line 303 are formed integrally with portions embedded in the contact holes 82 and 83 with polysilicon doped with an n-type impurity such as phosphorus. Further, a capacitor line 300 is formed above the capacitor electrode 302 with a capacitor insulating film 301 interposed therebetween.

Hereinafter, a manufacturing method of the TFT array substrate of the present embodiment, particularly a manufacturing method of the contact portion of the TFT 30 will be described with reference to FIG.
First, as shown in FIG. 4A, after a base insulating film 12 is formed on a substrate 10, an N-channel TFT 30 is formed on the base insulating film 12 by a known method. Next, a first interlayer insulating film 311 made of a silicon oxide film is deposited to a thickness of about 10 to 200 nm on the entire surface of the substrate including the scanning lines 3a and the gate insulating film 2 by a CVD method or the like.
Next, as shown in FIG. 4B, contact holes for electrically connecting the data line 303 to be formed later and the high concentration source region 1d and the storage capacitor 302 to be formed later and the high concentration drain region 1e. 82 and 83 are formed by a dry etching method or the like.
Next, as shown in FIG. 4C, an N-type doped polysilicon film is deposited on the entire surface of the first interlayer insulating film 311 by a low-pressure CVD method or the like, and patterned by a photolithography method to form the data line 303. Then, the capacitor electrode 302 is formed.
Then, by forming the capacitor insulating film 301 and the capacitor line 300, the TFT having the configuration shown in FIG. 3 is completed.

  According to the present embodiment, the pixel switching TFTs in the display area and the circuit forming TFTs in the peripheral circuit area are all N-channel TFTs, and are electrically connected to the source / drain regions of the TFT 30. Since the contact holes 82 and 83 are embedded with polysilicon doped with N-type impurities, the contact portion forming process can be simplified. Further, since the data line 303 and the capacitor electrode 302 are integrally formed with the doped polysilicon embedded in the contact holes 82 and 83, no additional process is required, and the present process can be performed with a simple manufacturing process. The configuration of the invention can be realized.

[Second Embodiment]
A method for manufacturing the liquid crystal device (electro-optical device) according to the second embodiment will be described below.
FIG. 5 is a process cross-sectional view for explaining a TFT manufacturing method, particularly a contact portion forming method. In the first embodiment, the upper conductive layer is formed of polysilicon embedded in the contact hole, but in this embodiment, an example using a polysilicon plug is given.

First, as shown in FIG. 5A, an N-channel TFT 33 is formed in each of the display region 31 and the peripheral circuit region 32 on the transparent substrate 30 by a conventional general method. Finally, the N-channel TFT 33 in the display area 31 becomes a pixel switching TFT, and the N-channel TFT 33 in the peripheral circuit area 32 becomes a circuit forming TFT.
Next, as shown in FIG. 5B, after forming a first interlayer insulating film 34 made of a silicon oxide film or the like covering each N-channel TFT 33, the first interlayer insulating film 34 is penetrated to form each TFT 33. A contact hole 35 reaching the source region 33s and the drain region 33d is formed. For example, the film thickness of the first interlayer insulating film 34 is about 800 nm.
Next, as shown in FIG. 5C, a polysilicon film 36 into which an N-type impurity such as phosphorus is introduced is formed on the entire surface of the substrate including the inside of the contact hole 35. At this time, the film thickness is set to such a degree that the polysilicon film 36 completely fills the inside of the contact hole 35 and is also formed on the upper surface of the first interlayer insulating film 34, for example, about 350 nm.

Next, as shown in FIG. 5D, the portion of the polysilicon film 36 located above the first interlayer insulating film 34 is removed using full-surface etching, CMP (Chemical Mechanical Polishing), or the like. The polysilicon plug 37 is formed by leaving the polysilicon only in the contact hole 35.
Next, as shown in FIG. 5E, a metal film such as aluminum is formed and patterned by using a photolithography technique, whereby a metal wiring layer 38 (upper layer wiring) is formed on the polysilicon plug 37 of each TFT 33. Layer). In the TFT 33 on the display region 31 side, the metal wiring layer 38 connected to the source region 33s becomes a data line as it is, and the metal wiring layer 38 connected to the drain region 33d is used as a relay conductor used for connection to the pixel electrode. Become a layer.

  Thereafter, the TFT array substrate 10 is completed by forming a second interlayer insulating film, a pixel electrode, an alignment film and the like by a conventional general method. On the other hand, the counter substrate 20 is completed by forming a solid common electrode, an alignment film, and the like on the transparent substrate. Then, the substrates 10 and 20 are bonded to each other through the sealing material 52, and the liquid crystal 50 is injected and sealed between the substrates 10 and 20, thereby completing the liquid crystal device 100 of the present embodiment.

  In the liquid crystal device 100 of the present embodiment, the pixel switching TFTs in the display region 31 and the circuit forming TFTs in the peripheral circuit region 32 are all composed of N-channel TFTs, and the polysilicon plug 37 is made of N-type polysilicon. Therefore, the contact portion forming process can be simplified, and the contact portion, and hence the TFT and wiring can be miniaturized. As a result, high definition of the liquid crystal device can be achieved. Further, if the external complementary driving LSI is electrically connected to the data line driving circuit, a data line driving circuit having sufficient driving performance can be realized.

[Electronics]
Hereinafter, a projection-type liquid crystal display device (liquid crystal projector) will be described as an example of an electronic apparatus using the above-described liquid crystal device.
FIG. 6 is a diagram showing a schematic configuration of the liquid crystal projector. As shown in this figure, a lamp unit 1102 made of a white light source such as a halogen lamp is provided inside the projector 1100. The projection light emitted from the lamp unit 1102 is separated into three primary colors of red (R), green (G), and blue (B) by three mirrors 1106 and two dichroic mirrors 1108 arranged inside. Are guided to the light valves 100R, 100G and 100B corresponding to the respective primary colors.

  Here, the configuration of the light valves 100R, 100G, and 100B is the same as that of the liquid crystal device according to the above-described embodiment, and R, G, and B primary colors supplied from a processing circuit (not shown) that inputs an image signal. Each is driven by a signal. In addition, B light has a long optical path compared to other R colors and G colors, and therefore, in order to prevent loss thereof, the B light passes through a relay lens system 1121 including an incident lens 1122, a relay lens 1123, and an exit lens 1124. Led.

The lights modulated by the light valves 100R, 100G, and 100B are incident on the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted by 90 degrees, while G light travels straight. In this manner, after the images of the respective colors are combined, a color image is projected onto the screen 1120 by the projection lens 1114.
The projection display device of this embodiment can achieve high resolution and low cost by including the liquid crystal device of the above embodiment.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the TFTs are all assumed to be N-channel type, but may be P-channel type. In that case, a polysilicon plug made of polysilicon into which a P-type impurity such as boron is introduced is used. It ’s fine. In addition, the description regarding the cross-sectional structure, the constituent material of each film, and the like is merely an example, and can be appropriately changed. Further, the present invention is not limited to a liquid crystal device, and various electric devices using, for example, electroluminescence (EL), a digital micromirror device (DMD, a registered trademark of Texas Instruments), or fluorescence by plasma emission or electron emission. Needless to say, the present invention can also be applied to an electro-optical device using an optical element and an electronic apparatus including the electro-optical device.

It is a top view which shows the liquid crystal device of the 1st Embodiment of this invention. It is sectional drawing which follows the H-H 'line | wire of FIG. It is sectional drawing which shows the TFT part of a liquid crystal device equally. It is a manufacturing process figure of TFT similarly. It is a manufacturing-process figure of the TFT part of the liquid crystal device of 2nd Embodiment. It is a schematic diagram which shows an example of the electronic device provided with the liquid crystal device. It is a manufacturing process figure of the conventional liquid crystal device. It is a figure which shows the continuation of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... TFT array substrate (active matrix substrate), 31 ... Display region, 32 ... Peripheral circuit region, 33 ... TFT (Thin film transistor), 34 ... First interlayer insulating film, 35 ... Contact hole, 37 ... Polysilicon plug (contact plug), 38 ... upper wiring layer, 100 ... liquid crystal device, 104 ... scanning line driving circuit (peripheral circuit), 201 ... data line driving circuit (peripheral circuit)

Claims (6)

An electro-optical device provided on a substrate with a display region having a plurality of pixel switching thin film transistors and a peripheral circuit region having a plurality of circuit forming thin film transistors,
The pixel switching thin film transistor in the display region and the circuit forming thin film transistor in the peripheral circuit region are all the same conductivity type thin film transistors, and contact holes for electrically connecting the source region or the drain region of each thin film transistor And polycrystalline silicon having the same conductivity type as the source region and drain region of the thin film transistor is embedded in the contact hole ,
An active matrix substrate having a plurality of data lines and a plurality of scanning lines provided so that the substrates cross each other;
The peripheral circuit region includes a data line driving circuit for driving the data line and a scanning line driving circuit for driving the scanning line, and an external complementary driving element is electrically connected to the data line driving circuit. An electro-optical device that is connected .   An upper conductive layer is provided on the upper layer side of each thin film transistor, and the source region or drain region and the upper conductive layer are electrically connected via a contact plug made of polycrystalline silicon embedded in the contact hole. The electro-optical device according to claim 1, wherein the electro-optical device is connected.   2. The electricity according to claim 1, wherein an upper conductive layer is provided on an upper layer side of each thin film transistor, and the upper conductive layer is integrally formed with polycrystalline silicon embedded in the contact hole. Optical device.   4. The electro-optical device according to claim 1, wherein a thickness of an active layer constituting each thin film transistor is 100 nm or less.   5. The electro-optical device according to claim 1, wherein an active layer constituting each thin film transistor is made of single crystal silicon. An electronic apparatus comprising the electro-optical device according to claim 1 .

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