JP2011221119A - Electro-optic device, electronic equipment, and manufacturing method of electro-optic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce light leak current with TFT of an electro-optic device such as a liquid crystal device.SOLUTION: An electro-optic device comprises: multiple pixel electrodes (9a) provided in a display area (10a); a data line (6a) that supplies image signals to pixel electrodes; a semiconductor layer (1a) that includes a source-drain region on the pixel electrode side (1e) that is electrically connected to the pixel electrodes, a source-drain region on the data line side (1d) that is electrically connected to the data line, and a channel region (1a') placed between the source-drain region on the pixel electrode side and the source-drain region on the data line side; and oppositely-placed gate electrodes (3b) in the channel region of the semiconductor layer via gate insulators (2a, 2b). In the semiconductor layer, the film thickness of the channel region is thinner than that of the source-drain region on the pixel electrode side and that of the source-drain region on the data line side.

Description

The present invention relates to a technical field of an electro-optical device such as a liquid crystal device, an electronic apparatus such as a liquid crystal projector including the electro-optical device, and a method of manufacturing the electro-optical device.

As this type of electro-optical device, for example, there is one used as light modulation means (so-called light valve) of a projection display device. In the projection display device, since relatively strong light from a light source is incident, a light shielding unit such as a light shielding film that blocks incident light is provided so that a light leakage current in a thin film transistor (TFT) is not generated.

For example, Patent Document 1 discloses a technique for realizing effective light shielding of TFTs by disposing a pixel electrode side LDD region in an intersecting region where a scanning line and a data line intersect.

JP 2008-203329 A

However, even if the light shielding performance of the TFT is improved by using the technology as described above,
For example, it is extremely difficult to prevent light such as oblique light from completely entering the TFT.
That is, the light shielding effect by the light shielding means such as a light shielding film is limited. Therefore, the technology described above includes
There is a technical problem that the light leakage current in the TFT may not be sufficiently reduced.

SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device and an electronic apparatus that can effectively reduce a light leakage current, and a method for manufacturing the electro-optical device.

In order to solve the above problems, an electro-optical device of the present invention is electrically connected to a plurality of pixel electrodes provided in a display region, a data line for supplying an image signal to the pixel electrodes, and the pixel electrodes. A semiconductor layer having a pixel electrode side source / drain region, a data line side source / drain region electrically connected to the data line, and a channel region located between the pixel electrode side source / drain region and the data line side source / drain region And a gate electrode disposed opposite to the channel region of the semiconductor layer with a gate insulating film interposed therebetween, wherein the semiconductor layer has a film thickness of the channel region, the pixel electrode side source / drain region and the data line It is formed to be thinner than the film thickness of the side source / drain region.

The electro-optical device of the present invention includes, for example, between an element substrate provided with a pixel switching TFT for electrically connecting a pixel electrode and a data line, and a counter substrate provided with a counter electrode facing the pixel electrode. And an electro-optical material such as liquid crystal. During the operation of the electro-optical device, an image signal is selectively supplied to the pixel electrode, whereby image display is performed in a pixel region (or image display region) in which a plurality of pixel electrodes are arranged. The image signal is supplied from the data line to the pixel electrode at a predetermined timing by turning on and off the TFT electrically connected between the data line and the pixel electrode.

In the present invention, a TFT is constituted by a semiconductor layer and a gate electrode arranged opposite to the channel region of the semiconductor layer via a gate insulating film. For example, a scanning signal is supplied to the gate electrode via a scanning line, and the on / off state of the TFT is switched at a predetermined timing. The semiconductor layer includes a pixel electrode side source / drain region electrically connected to the pixel electrode, a data line side source / drain region electrically connected to the data line, and a pixel electrode side source / drain region and a data line side source / drain region. It has a channel region located between them.

Here, in the present invention, in particular, the film thickness of the channel region in the semiconductor layer is formed so as to be smaller than the film thickness of the pixel electrode side source / drain region and the data line side source / drain region. That is, the semiconductor layer has a configuration in which the channel region is partially thinned.

The channel region in the semiconductor layer is a region where light leakage current is likely to occur as compared with other regions of the semiconductor layer (that is, the pixel electrode side source / drain region and the data line side source / drain region). The light leakage current tends to increase as the volume of the generated region increases. Therefore, if the channel region is formed so as to have a small thickness, the volume is reduced, and as a result, the light leakage current can be reduced.

On the other hand, the pixel electrode side source / drain region and the data line side source / drain region in the semiconductor layer are electrically connected to the pixel electrode and the data line via a contact hole. For this reason, it is desirable to form a relatively thick film as a margin when forming the contact hole. That is, it is desirable to have a sufficient film thickness to prevent overetching when forming the contact hole.

However, in the present invention, the channel region is formed thin, and the pixel electrode side source / drain region and the data line side source / drain region are formed thicker than the channel region. Therefore, it is possible to eliminate the disadvantages in manufacturing as described above.

As described above, according to the electro-optical device of the present invention, light leakage can be reduced,
It is possible to manufacture the apparatus suitably.

In the electro-optical device according to the aspect of the invention, the semiconductor layer includes a first junction region provided between the channel region and the data line side source / drain region, and between the channel region and the pixel electrode side source / drain region. The second junction region is formed so that the thickness of the second junction region is smaller than the thickness of the pixel electrode side source / drain region and the data line side source / drain region.

According to this aspect, the first junction region is provided as a data line side LDD (Lightly Doped Drain) region, for example, between the channel region and the data line side source / drain region. on the other hand,
Between the channel region and the pixel electrode side source / drain region, for example, a second junction region is provided as a pixel electrode side LDD region.

Here, in particular, the second junction region is a region where light leakage current is likely to occur as compared with other regions of the semiconductor layer. Therefore, if the film thickness of the second junction region is reduced, the light leakage current can be reduced extremely effectively.

In the aspect including the first junction region and the second junction region described above, the semiconductor layer includes the first junction region.
The junction region may be formed to have a thickness smaller than that of the pixel electrode side source / drain region and the data line side source / drain region.

If comprised in this way, in addition to a 2nd junction area | region, a 1st junction area | region will also be formed thinly. The first junction region is also a region where light leakage current is likely to occur as compared with the pixel electrode side source / drain region and the data line side source / drain region. Therefore, if the film thickness of the first junction region is reduced, the light leakage current can be reduced more effectively.

In another aspect of the electro-optical device of the present invention, the electro-optical device includes another semiconductor layer provided in a peripheral region located around the display region, and the other semiconductor layer has a thickness of the channel region, The electrode-side source / drain region and the data line-side source / drain region are not formed thinner than the film thickness.

According to this aspect, in the peripheral region located around the display region, for example, the TFT is provided as a part of the drive circuit. In this embodiment, in particular, in the other semiconductor layers constituting the TFT provided in the peripheral region, the film thickness of the channel region is made smaller than the film thickness of the source / drain region on the pixel electrode side and the source / drain region on the data line side. Not formed. That is, the semiconductor layer in the peripheral region has a different shape from the semiconductor layer in the display region.

Since the peripheral region is not a part that contributes to the display, light is not incident on the peripheral region. Therefore, compared with the display region, the light leakage current is hardly generated. Therefore, even if the channel region of the semiconductor layer is not formed to be thin, the light leakage current is sufficiently reduced.

According to the configuration described above, the channel region of the semiconductor layer can be thinned only in the display region, so that the device configuration and the manufacturing process can be prevented from becoming complicated and the manufacturing cost can be prevented from increasing.

In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

According to the electronic apparatus of the present invention, since the electro-optical device according to the present invention described above is provided,
Various electronic devices such as a projection display device with high reliability, a television, a mobile phone, an electronic notebook, a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a video phone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper can be realized.

In order to solve the above problems, a method for manufacturing an electro-optical device of the present invention includes a semiconductor forming step of forming a semiconductor layer, a step of forming an insulating film on the semiconductor layer, and the semiconductor layer in the insulating film. A first removal step of removing a portion overlapping with a region to be a channel region, an oxidation step of oxidizing the surface of the semiconductor layer exposed from the insulating film to oxidize the surface, the insulating film and the semiconductor A second removal step of removing a portion of the layer oxidized by the oxidation treatment, a region forming step of forming a channel region, a pixel electrode side source / drain region, and a data line side source / drain region in the semiconductor layer, A gate electrode forming step for forming a gate electrode so as to face the channel region, and a data line electrically connected to the source / drain region on the data line side Comprising a data line forming step of forming, and forming a pixel electrode so as to be electrically connected to the pixel electrode side source drain regions.

According to the method for manufacturing an electro-optical device of the present invention, when a semiconductor layer constituting a TFT is formed, an insulating film containing SiO ₂ or the like is formed thereon. And the part which overlaps with the area | region which should become a channel region of the semiconductor layer in an insulating film is removed. That is, the insulating film has a partially opened shape.

In the present invention, in particular, the exposed surface of the semiconductor layer is oxidized by performing oxidation treatment from the opening of the insulating film. Then, the surface portion of the oxidized semiconductor layer is removed together with the insulating film. As a result, the region to be the channel region of the semiconductor layer is thinner than the other regions. That is, it is thinned by the amount removed by oxidation.

A channel region, a pixel electrode side source / drain region, and a data line side source / drain region are formed in the semiconductor layer. A gate electrode is disposed opposite to the channel region with a gate insulating film interposed therebetween. For example, the data line is electrically connected to the data line side source / drain region through a contact hole. The pixel electrode is electrically connected to the pixel electrode side source / drain region through, for example, a contact hole.

In the present invention, the channel region of the semiconductor layer is formed thinner than the pixel electrode side source / drain region and the data line side source / drain region. Therefore, light leakage current generated in the semiconductor layer can be reduced.

On the other hand, the pixel electrode side source / drain region and the data line side source / drain region are formed thicker than the channel region. Therefore, overetching or the like when forming the contact hole can be prevented.

As described above, according to the electro-optical device manufacturing method of the present invention, it is possible to reduce light leakage and to manufacture the device suitably.

In the electro-optical device manufacturing method of the present invention, various aspects similar to the various aspects of the electro-optical device of the present invention described above can be employed.

The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

1 is a plan view illustrating an overall configuration of an electro-optical device according to an embodiment. It is the HH 'sectional view taken on the line of FIG. FIG. 6 is an equivalent circuit diagram of various elements, wirings, and the like in the image display region of the electro-optical device according to the embodiment. FIG. 3 is a plan view showing a plurality of adjacent pixel units in the electro-optical device according to the embodiment. FIG. 5 is a cross-sectional view taken along line A-A ′ of FIG. 4. FIG. 6 is a process cross-sectional view (part 1) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 2) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 3) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 4) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 5) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 6) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 12 is a process cross-sectional view (part 7) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 8) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. FIG. 12 is a process cross-sectional view (part 9) illustrating the manufacturing process of the electro-optical device according to the embodiment in order. It is a top view which shows the structure of the projector which is an example of the electronic device to which the electro-optical apparatus is applied.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Electro-optical device>
The electro-optical device according to the present embodiment will be described with reference to FIGS. In the following embodiments, a TFT active matrix driving type liquid crystal device with a built-in driving circuit will be described as an example of the electro-optical device of the present invention.

First, the overall configuration of the electro-optical device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing the overall configuration of the electro-optical device according to this embodiment.
2 is a cross-sectional view taken along line HH ′ of FIG.

1 and 2, in the electro-optical device according to the present embodiment, a TFT array substrate 10 and a counter substrate 20 are disposed to face each other. The TFT array substrate 10 is, for example, a transparent substrate such as a quartz substrate or a glass substrate, a silicon substrate, or the like. The counter substrate 20 is a transparent substrate such as a quartz substrate or a glass substrate. Between the TFT array substrate 10 and the counter substrate 20, there is a liquid crystal layer 5.
0 is enclosed. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between a pair of alignment films.

The TFT array substrate 10 and the counter substrate 20 are bonded to each other by a sealing material 52 provided in a sealing region located around the image display region 10a provided with a plurality of pixel electrodes.

The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and after being applied on the TFT array substrate 10 in the manufacturing process,
It is cured by heating or the like. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance between the TFT array substrate 10 and the counter substrate 20 (that is, the inter-substrate gap) to a predetermined value is dispersed. The gap material is used as the sealing material 52.
In addition to or instead of those mixed in the image display area 10a or the image display area 10a
You may make it arrange | position to the peripheral region located in the periphery of.

A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. A part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, the image display area 10 is thus obtained.
In order to connect the two scanning line driving circuits 104 provided on both sides of a, the TFT array substrate 1
A plurality of wirings 105 are provided along one remaining side of 0 and so as to be covered with the frame light shielding film 53.

In a region facing the four corners of the counter substrate 20 on the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with a vertical conduction material are arranged. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

In FIG. 2, on the TFT array substrate 10, a pixel switching T as a driving element is formed.
A laminated structure in which wirings such as FT, scanning lines, and data lines are formed is formed. Although the detailed configuration of this laminated structure is not shown in FIG. 2, ITO (In
A pixel electrode 9a made of a transparent material such as (dium tin oxide) is formed in an island shape in a predetermined pattern for each pixel.

The pixel electrode 9 a is formed in the image display area 10 a on the TFT array substrate 10 so as to face the counter electrode 21. On the surface of the TFT array substrate 10 facing the liquid crystal layer 50, that is, on the pixel electrode 9a, an alignment film 16 is formed so as to cover the pixel electrode 9a.

A light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. For example, the light shielding film 23 is formed in a lattice shape when viewed in plan on the facing surface of the facing substrate 20. In the counter substrate 20, a non-opening area is defined by the light shielding film 23, and an area partitioned by the light shielding film 23 is an opening area through which light emitted from, for example, a projector lamp or a direct viewing backlight is transmitted. The light shielding film 23 may be formed in a stripe shape, and the non-opening region may be defined by the light shielding film 23 and various components such as data lines provided on the TFT array substrate 10 side.

On the light shielding film 23, a counter electrode 21 made of a transparent material such as ITO is formed so as to face the plurality of pixel electrodes 9a. Further, in order to perform color display in the image display area 10a, a color filter (not shown in FIG. 2) may be formed on the light shielding film 23 in an area including a part of the opening area and the non-opening area. Good. On the opposite surface of the opposite substrate 20,
An alignment film 22 is formed on the counter electrode 21.

Note that the data line driving circuit 1 described above is provided on the TFT array substrate 10 shown in FIGS.
01, a sampling circuit that samples the image signal on the image signal line and supplies it to the data line in addition to the driving circuit such as the scanning line driving circuit 104, and a precharge signal having a predetermined voltage level precedes the image signal to a plurality of data lines In addition, a precharge circuit to be supplied, an inspection circuit for inspecting quality, defects, and the like of the electro-optical device during manufacture or shipment may be formed.

Next, an electrical configuration of the pixel portion of the electro-optical device according to the present embodiment will be described with reference to FIG. FIG. 3 is an equivalent circuit diagram of various elements, wirings, and the like in a plurality of pixels formed in a matrix forming the image display area of the electro-optical device according to this embodiment.

In FIG. 3, a pixel electrode 9a and a TFT 30 are formed in each of a plurality of pixels formed in a matrix that forms the image display region 10a. The TFT 30 includes a pixel electrode 9a
The pixel electrode 9a is switching-controlled during operation of the electro-optical device according to the present embodiment. The data line 6a to which the image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. May be.

The scanning line 11 is electrically connected to the gate of the TFT 30, and the electro-optical device according to the present embodiment pulse-scans the scanning signals G 1, G 2,.
-It is comprised so that Gm may be applied in a line-sequential order in this order. The pixel electrode 9a is a TFT
The image signal S1, S supplied from the data line 6a is electrically connected to the drain of the TFT 30, and the TFT 30 as a switching element is closed for a certain period.
2, ..., Sn are written at a predetermined timing. A predetermined level of image signals S1, S2,..., Sn written in the liquid crystal as an example of the electro-optical material via the pixel electrode 9a is held for a certain period with the counter electrode formed on the counter substrate. The

The liquid crystal constituting the liquid crystal layer 50 (see FIG. 2) modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. For example, in the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel. In the normally black mode, the transmittance is applied in units of each pixel. As a result, the transmittance for incident light is increased, and light having a contrast corresponding to an image signal is emitted from the electro-optical device as a whole.

In order to prevent the image signal held here from leaking, the pixel electrode 9a and the counter electrode 2
1 (see FIG. 2), a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between them. The storage capacitor 70 is a capacitive element that functions as a storage capacitor that temporarily holds the potential of each pixel electrode 9a in response to supply of an image signal. One electrode of the storage capacitor 70 is electrically connected to the drain of the TFT 30 in parallel with the pixel electrode 9a, and the other electrode is electrically connected to the capacitor line 300 having a fixed potential so as to have a constant potential. ing. According to the storage capacitor 70, the potential holding characteristic of the pixel electrode 9a is improved, and the display characteristics such as improvement of contrast and reduction of flicker can be improved.

Next, a specific configuration of the pixel portion that realizes the above-described operation will be described with reference to FIGS. FIG. 4 is a plan view showing a plurality of adjacent pixel portions in the electro-optical device according to this embodiment, and FIG. 5 is a cross-sectional view taken along line AA ′ of FIG. In FIGS. 4 and 5, the scale of each layer / member is different for each layer / member to have a size that can be recognized on the drawing. In FIG. 4, for convenience of explanation, among the layers shown in FIG.
The layer on the upper layer side from 0 is omitted.

4 and 5, the TFT 30 includes the semiconductor layer 1a and the gate electrode 3b.

The semiconductor layer 1a is made of, for example, polysilicon, and has a channel region 1a ′ having a channel length along the Y direction, a data line side LDD region 1b, a pixel electrode side LDD region 1c, a data line side source / drain region 1d, and a pixel electrode side. It consists of a source / drain region 1e. That is,
The TFT 30 has an LDD structure. Here, the data line side LDD region 1b is an example of the “first junction region” in the present invention, and the pixel electrode side LDD region 1c is an example of the “second junction region” in the present invention.

The data line side source / drain region 1d and the pixel electrode side source / drain region 1e are formed substantially in mirror symmetry along the Y direction with respect to the channel region 1a ′. The data line side LDD region 1b is formed between the channel region 1a 'and the data line side source / drain region 1d. The pixel electrode side LDD region 1c is formed between the channel region 1a ′ and the pixel electrode side source / drain region 1e.

The data line side LDD region 1b, the pixel electrode side LDD region 1c, the data line side source / drain region 1d, and the pixel electrode side source / drain region 1e are formed by implanting impurities into the semiconductor layer 1a by an impurity implantation such as an ion implantation method. This is an impurity region.
The data line side LDD region 1b and the pixel electrode side LDD region 1c are formed as low concentration impurity regions with less impurities than the data line side source / drain region 1d and the pixel electrode side source / drain region 1e, respectively. According to such an impurity region, when the TFT 30 is not operating, the off-current flowing between the source region and the drain region is reduced, and the TFT 30
It is possible to suppress a decrease in on-current flowing during the operation.

The TFT 30 preferably has an LDD structure, but the data line side LDD region 1b.
An offset structure in which no impurity is implanted into the pixel electrode side LDD region 1c may be used, and impurities are implanted at a high concentration using the gate electrode as a mask to form the data line side source / drain region and the pixel electrode side source / drain region. It may be self-aligned.

Here, in this embodiment, in particular, the channel region 1a ′ in the semiconductor layer 1a, the data line side L
The DD region 1b and the pixel electrode side LDD region 1c are formed to be thinner than the data line side source / drain region 1d and the pixel electrode side source / drain region 1e.

The channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c in the semiconductor layer 1a are more likely to generate a light leakage current than the data line side source / drain region 1d and the pixel electrode side source / drain region 1e. It is an area. And this optical leakage current is
It tends to increase as the volume of the generated region increases. Therefore, if the channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c are formed so as to be thin, their respective volumes are reduced, and as a result, the light leakage current can be reduced. it can.

Note that when compared with the data line side LDD region 1b and the pixel electrode side LDD region 1c, a light leak current is likely to occur in the pixel electrode side LDD region 1c. Therefore, the film thickness of the data line side LDD region 1b is set to the data line side source / drain region 1d and the pixel electrode side source / drain region 1e.
Even if the configuration is such that only the film thickness of the pixel electrode side LDD region 1c is reduced, the above-described effects can be obtained accordingly.

The data line side source / drain region 1d in the semiconductor layer 1a is electrically connected to the data line 6a through the contact hole 81, and the pixel electrode side source / drain region 1e is
It is electrically connected to the lower capacitor electrode 71 through the contact hole 83. In this embodiment, the semiconductor layer 1a is thinned in the channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c, and the data line side source / drain region 1
d and the pixel electrode side source / drain region 1e are formed relatively thick. Therefore,
It is possible to prevent overetching when the contact holes 81 and 83 are formed.

4 and 5, the gate electrode 3b is made of, for example, conductive polysilicon. The gate electrode 3b is electrically connected to the scanning line 11 through contact holes 34a and 34b, and is disposed so as to overlap with the channel region 1a ′ in the semiconductor layer 1a. Between the gate electrode 3b and the semiconductor layer 1a, a gate oxide film 2a and a gate insulating film 2b are provided.
Is insulated by.

In FIG. 5, the scanning line 11 is provided on the lower layer side of the TFT 30 on the TFT array substrate 10 through the base insulating film 12. The scanning line 11 is configured by stacking refractory metals such as Ti (titanium), for example. The scanning line 11 is incident on the TFT array substrate 10 from the side of the TFT array substrate 10 such as back-surface reflection on the TFT array substrate 10 or light emitted from another liquid crystal device by a multi-plate projector or the like and penetrating the composite optical system. The channel region 1a ′ of the TFT 30 and its periphery are shielded from light.

In addition to the function of insulating the TFT 30 from the scanning line 11 between layers, the base insulating film 12 is formed on the entire surface of the TFT array substrate 10 so that the surface of the TFT array substrate 10 is roughened when it is polished, or remains after cleaning. Thus, the pixel switching TFT 30 has a function of preventing deterioration of characteristics.

In FIG. 5, a storage capacitor 70 is provided on the upper layer side of the TFT 30 on the TFT array substrate 10 via the first interlayer insulating film 41. The storage capacitor 70 is formed by arranging a lower capacitor electrode 71 and an upper capacitor electrode 72 to face each other with a dielectric film 75 therebetween.

The upper capacitor electrode 72 is a fixed potential side capacitor electrode that is electrically connected to a constant potential source and maintained at a fixed potential. The upper capacitor electrode 72 is formed of a non-transparent metal film containing a metal or alloy such as Al (aluminum) or Ag (silver), for example, and also functions as an upper light shielding film (built-in light shielding film) that shields the TFT 30. To do. The upper capacitor electrode 72 is made of, for example, Ti, Cr, W
, Ta, Mo, Pd, or other high-melting point metals, and may be composed of a single metal, an alloy, a metal silicide, a polysilicide, or a laminate of these. In this case, the function of the upper capacitor electrode 72 as a built-in light shielding film can be enhanced.

The lower capacitor electrode 71 is made of, for example, conductive polysilicon, and functions as a pixel potential side capacitor electrode electrically connected to the pixel electrode side source / drain region 1e of the TFT 30 and the pixel electrode 9a. More specifically, the lower capacitor electrode 71 is electrically connected to the pixel electrode side source / drain region 1 e through the contact hole 83 and electrically connected to the relay layer 93 through the contact hole 84. Yes. Further, the relay layer 93 is electrically connected to the pixel electrode 9 a through the contact hole 85. That is, the lower capacitor electrode 71 relays the electrical connection between the pixel electrode side source / drain region 1e and the pixel electrode 9a together with the relay layer 93. The lower capacitance electrode 71 has a function as a light absorption layer or a light shielding film disposed between the upper capacitance electrode 72 as an upper light shielding film and the TFT 30 in addition to the function as a pixel potential side capacitance electrode.

The dielectric film 75 is, for example, an HTO (High Temperature Oxide) film or an LTO (Low Temperat).
It has a single layer structure or a multilayer structure composed of a silicon oxide (SiO 2) film such as a ure oxide film or a silicon nitride (SiN) film.

In FIG. 5, a data line 6 a and a relay layer 93 are provided on the upper layer side of the storage capacitor 70 on the TFT array substrate 10 via the second interlayer insulating film 42.

The data line 6a is electrically connected to the data line side source / drain region 1d of the semiconductor layer 1a through a contact hole 81 penetrating the first interlayer insulating film 41 and the second interlayer insulating film. The inside of the data line 6a and the contact hole 81 is, for example, Al—Si—Cu,
Al (aluminum) -containing material such as Al-Cu, Al alone, or Al layer and TiN
It consists of a multilayer film with layers. The data line 6a also has a function of shielding the TFT 30 from light.

The relay layer 93 is formed on the second interlayer insulating film 42 in the same layer as the data line 6a.
For the data line 6a and the relay layer 93, a thin film made of a conductive material such as a metal film is formed on the second interlayer insulating film 42 by using a thin film forming method, and the thin film is partially removed. It forms in the state mutually spaced apart by patterning. Therefore, since the data line 6a and the relay layer 93 can be formed in the same process, the manufacturing process of the device can be simplified.

In FIG. 5, the pixel electrode 9a is formed on the upper layer side through the third interlayer insulating film 43 relative to the data line 6a. The pixel electrode 9a includes a lower capacitor electrode 71 and contact holes 83 and 84.
And 85 and the relay layer 93 are electrically connected to the pixel electrode side source / drain region 1e of the semiconductor layer 1a. The contact hole 85 is formed by depositing a conductive material constituting the pixel electrode 9a such as ITO on the inner wall of a hole formed so as to penetrate the interlayer insulating layer 43. Although not shown here, an alignment film subjected to a predetermined alignment process such as a rubbing process is provided on the upper surface of the pixel electrode 9a.

The configuration of the pixel portion described above is common to each pixel portion as shown in FIG. Image display area 1
Such pixel portions are periodically formed at 0a (see FIG. 1).

As described above, according to the electro-optical device according to the present embodiment, the channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c in the semiconductor layer are formed thin. Light leakage can be reduced, and the apparatus can be preferably manufactured.

<Method of manufacturing electro-optical device>
Next, a method for manufacturing the electro-optical device according to this embodiment will be described with reference to FIGS. 6 to 14 respectively show the manufacturing process of the electro-optical device according to this embodiment.
It is process sectional drawing shown in order. 6 to 14, for convenience of description, TFTs in a pixel and TFTs in a driver (that is, the data line driving circuit 101 and the scanning line driving circuit 104) are shown side by side. In the following, the manufacturing process of the TFT 30 deeply related to the present invention will be described in detail, and the description of the other manufacturing processes will be omitted.

In FIG. 6, in the method of manufacturing the electro-optical device according to this embodiment, first, the semiconductor layer 1 a is provided on the base insulating film 11. An insulating film 400 is provided on the semiconductor layer 1a. The insulating film 400 includes, for example, SiO ₂ and is formed so as to cover the entire surface of the TFT array substrate 10.

In FIG. 7, a mask 510 is formed on the insulating film 400 and wet etching is performed. The mask 510 includes the channel region 1a of the semiconductor layer 1a on the pixel portion side and the data line side LD.
They are not provided in the regions to be the D region 1b and the pixel electrode side LDD region 1c (see FIG. 5). On the other hand, the entire surface of the semiconductor layer 1 a on the driver side is covered with the mask 510.

In FIG. 8, as a result of wet etching, the insulating film 400 is partially removed, and the semiconductor layer 1 a on the pixel portion side is partially exposed from the opening 410. On the other hand, the semiconductor layer 1 on the driver side
a is not exposed.

In FIG. 9, the semiconductor layer 1a on the pixel portion side is subjected to, for example, an oxidation process by heat. Thus, an oxide film 200 is formed on the surface of the semiconductor layer 1a on the pixel portion side exposed from the insulating film 400.

In FIG. 10, after the oxidation process, the insulating film 4 is obtained by performing etch back.
00 is removed. At this time, the oxide film 200 formed on the pixel-side semiconductor layer 1a is also removed. Therefore, the semiconductor layer 1a on the pixel side has a shape in which the central portion is recessed.

In FIG. 11, a gate oxide film 2a and a gate insulating film 2b are formed on the semiconductor layer 1a. Then, channel doping is performed on the semiconductor layer 1a through the gate oxide film 2a and the gate insulating film 2b.

In FIG. 12, after channel doping, a gate electrode 3b is formed on the gate insulating film 2b. When the gate insulating film 3b is formed, N ⁻ ions are implanted into the semiconductor layer 1a. At this time, the gate insulating film 3b functions as a mask.

In FIG. 13, N ⁻ ions are not implanted into a region of the semiconductor layer 1a that overlaps with the gate insulating film 3b. Thereby, the channel region 1a is formed. A mask 520 is formed on the gate electrode 3b, and N ⁺ ions are implanted into the semiconductor layer 1a.

In FIG. 14, the region where N ⁺ ions are implanted is the data line side source / drain region 1.
d and the pixel electrode side source / drain region 1e. The regions where N ⁺ ions are not implanted become the data line side LDD region 1b and the pixel electrode side LDD region 1c. In this way, the TFT 30 is completed.

According to the manufacturing method of the electro-optical device according to this embodiment, the channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c in the semiconductor layer 1a on the pixel unit side are formed thin. Therefore, it is possible to reduce the light leak and to manufacture the apparatus suitably.

On the other hand, the semiconductor layer 1a on the driver side includes a channel region 1a ′ and a data line side LDD region 1.
The film thickness of b and the pixel electrode side LDD region 1c is not formed thin. That is, the semiconductor layer 1a on the driver side has a different shape from the semiconductor layer 1a in the pixel portion.

Since the area where the driver is provided is not a part that contributes to display and is configured such that light is not incident thereon, light leakage current hardly occurs compared to the display area. Therefore, even if the channel region of the semiconductor layer 1a is not formed to be thin, the light leakage current is sufficiently reduced.

In the present embodiment, the channel region 1a ′, the data line side LDD region 1b, and the pixel electrode side LDD region 1c of the semiconductor layer 1a only need to be thinned by only the pixel portion. An increase in cost can be prevented.

<Electronic equipment>
Next, the case where the liquid crystal device which is the above-described electro-optical device is applied to various electronic devices will be described. FIG. 15 is a plan view showing a configuration example of the projector. Hereinafter, a projector using the liquid crystal device as a light valve will be described.

As shown in FIG. 15, a projector 1100 includes a lamp unit 1102 made up of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112,
While the R and B light is refracted at 90 degrees, the G light goes straight. Therefore, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B.

The liquid crystal panels 1110R, 1110B and 1110G include a dichroic mirror 1
Since light corresponding to the primary colors of R, G, and B is incident by 108, it is not necessary to provide a color filter.

In addition to the electronic device described with reference to FIG. 15, a mobile personal computer, a mobile phone, an LCD TV, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic device Examples include notebooks, calculators, word processors, workstations, videophones, POS terminals, and devices with touch panels. Needless to say, the present invention can be applied to these various electronic devices.

In addition to the liquid crystal devices described in the above embodiments, the present invention is not limited to a reflective liquid crystal device (LCO).
S), plasma display (PDP), field emission display (FED, SED),
The present invention can also be applied to an organic EL display, a digital micromirror device (DMD), an electrophoresis apparatus, and the like.

The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change. In addition, an electronic apparatus including the electro-optical device and a method for manufacturing the electro-optical device are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1a ... Semiconductor layer, 1a '... Channel region, 1b ... Data line side LDD region, 1c ... Pixel electrode side LDD region, 1d ... Data line side source / drain region, 1e ... Pixel electrode side source / drain region, 3b ... Gate electrode, 6a ... data line, 9a ... pixel electrode, 10 ... TFT array substrate, 10a ... image display area, 11 ... scanning line, 12 ... underlying insulating film, 20 ... counter substrate, 30 ... T
FT, 50 ... liquid crystal layer, 70 ... storage capacitor, 200 ... oxide film, 400 ... insulating film, 510, 52
0 ... Mask

Claims (6)

A plurality of pixel electrodes provided in the display area;
A data line for supplying an image signal to the pixel electrode;
A pixel electrode side source / drain region electrically connected to the pixel electrode, a data line side source / drain region electrically connected to the data line, and the pixel electrode side source / drain region and the data line side source / drain region A semiconductor layer having a channel region positioned therebetween;
A gate electrode disposed opposite to the channel region of the semiconductor layer via a gate insulating film;
With
The electro-optical device, wherein the semiconductor layer is formed so that a film thickness of the channel region is thinner than a film thickness of the pixel electrode side source / drain region and the data line side source / drain region. The semiconductor layer is
A first junction region provided between the channel region and the data line side source / drain region, and a second junction region provided between the channel region and the pixel electrode side source / drain region,
2. The electro-optic according to claim 1, wherein the film thickness of the second junction region is smaller than the film thickness of the pixel electrode side source / drain region and the data line side source / drain region. apparatus. 3. The semiconductor layer is formed so that the film thickness of the first junction region is thinner than the film thickness of the pixel electrode side source / drain region and the data line side source / drain region. The electro-optical device according to 1. Another semiconductor layer provided in a peripheral region located around the display region;
The other semiconductor layer is not formed so that a film thickness of the channel region is thinner than a film thickness of the pixel electrode side source / drain region and the data line side source / drain region. 4. The electro-optical device according to any one of items 1 to 3. An electronic apparatus comprising the electro-optical device according to claim 1. A semiconductor formation step of forming a semiconductor layer;
Forming an insulating film on the semiconductor layer;
A first removal step of removing a portion of the insulating film that overlaps a region to be a channel region of the semiconductor layer;
An oxidation step of oxidizing the surface of the semiconductor layer exposed from the insulating film by oxidizing the surface;
A second removal step of removing a portion oxidized by the oxidation treatment in the insulating film and the semiconductor layer;
Forming a channel region, a pixel electrode side source / drain region, and a data line side source / drain region in the semiconductor layer;
Forming a gate electrode so as to face the channel region; and forming a data line so as to be electrically connected to the data line side source / drain region;
And a step of forming a pixel electrode so as to be electrically connected to the pixel electrode side source / drain region.

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