JP2010123909A - Electro-optical device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an optical leakage current of a semiconductor element such as an element for pixel switching without increasing the rate of occupation of an image display region of a liquid crystal device by a non-opening region. <P>SOLUTION: On a TFT array substrate 10, a projection 42a is formed in an island shape covering a semiconductor layer 1a. A light shield film 25 extends over an upper surface and a side surface of the projection 42a. The light shield film 25 may be formed by: forming a light shield film of large size enough to extend to the projection 42a and its periphery and then patterning the light shield film of the large size such that the light shield film 25 remains on the upper surface and the side surface of the projection 42a; or forming the film by a CVD method on the upper surface and the side surface of the projection 42a. The semiconductor layer 1a is covered with the light shield film 25 from its upper side and side surface side in three-dimensional view. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of, for example, an electro-optical device such as a liquid crystal device and a manufacturing method thereof.

  In a liquid crystal device that is an example of this type of electro-optical device, a light shielding film that shields a TFT provided in each pixel portion as a pixel switching element is often provided on an upper layer side and a lower layer side of the element (Patent Literature). 1). The light-shielding film is provided in a non-opening region that does not transmit light and is provided in a non-opening region that does not transmit light on a substrate on which a semiconductor element such as a TFT is formed. Reduce optical leakage current.

JP 2000-164875 A

  However, when the size of the light-shielding film is increased for the purpose of shielding the TFT by the light-shielding film, the proportion of the non-opening area in the display area for displaying the image increases, and the liquid crystal device displays the image. There arises a problem that the display performance is lowered.

  Therefore, the present invention has been made in view of the above problems and the like. For example, without increasing the ratio of the non-opening area in the display area, more preferably, while reducing the ratio of the non-opening area, the pixel It is an object of the present invention to provide an electro-optical device capable of reducing light leakage current in a semiconductor element such as a switching element, and a manufacturing method thereof.

  In order to solve the above problems, an electro-optical device according to the present invention includes a semiconductor layer formed in a display region on a substrate, a convex portion formed in an island shape so as to cover the semiconductor layer, and a A light shielding film extending on each of the upper surface and the side surface.

  The electro-optical device according to the present invention is formed, for example, by patterning a semiconductor film such as a polysilicon film formed on a substrate into a predetermined shape. Such a semiconductor layer is, for example, a semiconductor portion in which a channel region, a source region, and a drain region of a pixel switching TFT to be formed in a display region on a substrate are to be formed.

  The convex portion is formed in an island shape so as to cover the semiconductor layer. The convex portion is formed, for example, by partially removing an interlayer film such as an insulating film formed on the semiconductor layer by using a patterning method such as etching.

  The light shielding film extends on each of the upper surface and the side surface of the convex portion. For example, after the light shielding film having a large size is formed so as to extend to the convex portion and its periphery, the large size light shielding film is patterned so that the light shielding film remains on the upper surface and the side surface of the convex portion. Alternatively, the film may be formed on the upper surface and the side surface of the convex portion using film formation such as CVD.

  Therefore, according to the electro-optical device according to the present invention, the semiconductor layer is covered with the light shielding film from each of the upper side surface and the side surface side in three dimensions. Therefore, according to the electro-optical device according to the present invention, the light applied to the semiconductor layer from the upper surface and the side surface of the semiconductor layer from the substrate can be reliably blocked by the light shielding film. In addition, according to the electro-optical device according to the present invention, the light shielding property is improved while reducing the area of the light shielding film in a plan view as compared with the case where the light shielding film is formed flat along the substrate surface of the substrate. be able to. More specifically, for example, the width of the non-opening region that separates the opening regions of the pixel regions adjacent to each other among the plurality of pixel regions constituting the display region corresponds to the size of the light shielding film. The aperture ratio in the pixel region can be increased by reducing the planar area, that is, the size of the light-shielding film while improving the light-shielding property.

  Therefore, according to the electro-optical device according to the present invention, the opening region narrowed by the light-shielding film can be prevented from being reduced as much as possible, the display performance of the electro-optical device can be improved, and the semiconductor layer can be improved. The light leakage current can be reduced by improving the light shielding property.

  In one aspect of the electro-optical device according to the invention, a distance from the upper surface of the semiconductor layer to the light shielding film may be larger than a distance from an edge of the semiconductor layer to the side surface.

  According to this aspect, the light shielding film can be formed on the upper surface and the side surface of the convex portion so that the semiconductor layer can be shielded efficiently.

  In another aspect of the electro-optical device according to the invention, the semiconductor layer constitutes a part of a thin film transistor that is a switching element that performs switching control of each of a plurality of pixel portions constituting the display region, The thin film transistor may be formed in a non-opening region that separates open regions in the display region.

  According to this aspect, it is possible to increase the proportion of the display area occupied by the aperture area, that is, the aperture ratio, and to improve the display performance of the electro-optical device.

  In order to solve the above problems, a method for manufacturing an electro-optical device according to the present invention includes a first step of forming a semiconductor layer in a display region on a substrate, and forming a convex portion in an island shape so as to cover the semiconductor layer. A second step and a third step of forming a light-shielding film extending on each of the upper surface and the side surface of the convex portion.

  According to the method for manufacturing an electro-optical device according to the present invention, similarly to the electro-optical device described above, it is possible to prevent the opening area narrowed by the light-shielding film from being narrowed as much as possible, and to improve the display performance of the electro-optical device. In addition, it is possible to manufacture an electro-optical device that can reduce the light leakage current by increasing the light shielding property to the semiconductor layer.

  In one aspect of the method of manufacturing the electro-optical device according to the invention, the second step includes a fourth step of forming an interlayer film on the semiconductor layer, and the interlayer film is partially removed, thereby And a fifth step of forming a convex portion.

  According to this aspect, the convex portion can be easily formed.

  In this aspect, in the fifth step, the interlayer film is partially removed so that the distance from the upper surface of the semiconductor layer to the light shielding film is larger than the distance from the edge of the semiconductor layer to the side surface. May be.

  According to this aspect, in the third step to be performed later, it is possible to form the convex portion so that the light shielding film covering the semiconductor layer can be easily formed.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

It is a top view which shows the whole structure of the liquid crystal device which concerns on this embodiment. It is II-II 'sectional drawing of FIG. 4 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixel portions formed in a matrix that forms an image display region of the liquid crystal device according to the present embodiment. It is a top view of the pixel part of the liquid crystal device concerning this embodiment. It is VV 'sectional drawing of FIG. It is process top view (the 1) which showed in a turn the main processes of the manufacturing method of the liquid crystal device concerning this embodiment. It is process top view (the 2) which showed the main process of the manufacturing method of the liquid crystal device concerning this embodiment in order.

  Hereinafter, an electro-optical device and a manufacturing method thereof according to the present invention will be described with reference to the drawings. Hereinafter, a liquid crystal device will be described as an embodiment of the electro-optical device according to the invention.

<1: Liquid crystal device>
<1-1: Overall Configuration of Liquid Crystal Device>
First, the overall configuration of the liquid crystal device 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the liquid crystal device 1 as seen from the counter substrate side together with the components formed on the TFT array substrate, and FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG.

  1 and 2, in the liquid crystal device 1, a TFT array substrate 10, which is an example of the “substrate” of the present invention, and a counter substrate 20 are disposed to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are images that are display regions in which a plurality of pixel portions 72 (see FIG. 3) are provided. They are bonded to each other by a sealing material 52 provided in a sealing area located around the display area 10a.

  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 is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  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. However, 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. There is a peripheral area located around the image display area 10a. In other words, particularly in the present embodiment, when viewed from the center of the TFT array substrate 10, the distance from the frame light shielding film 53 is defined as the peripheral region.

  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, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10 a in this way, a plurality of the pixel lines are covered along the remaining side of the TFT array substrate 10 and covered with the frame light shielding film 53. Wiring 105 is provided.

  Vertical conductive members 106 functioning as vertical conductive terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corner portions. 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, an alignment film 16 (see FIG. 5) is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. ing. On the other hand, on the counter substrate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed on the uppermost layer portion. 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 the pair of alignment films.

  1 and 2, on the TFT array substrate 10, in addition to the drive circuits such as the data line drive circuit 101 and the scanning line drive circuit 104, the image signal on the image signal line is sampled to obtain data. Sampling circuit that supplies lines, precharge circuit that supplies pre-charge signals of a predetermined voltage level to multiple data lines in advance of image signals, inspection of quality, defects, etc. of the electro-optical device during production or shipment An inspection circuit or the like may be formed.

<1-2: Electrical configuration of liquid crystal device>
Next, the electrical configuration of the liquid crystal device 1 will be described with reference to FIG. FIG. 3 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixel portions formed in a matrix that forms the image display region 10 a of the liquid crystal device 1.

  In FIG. 3, a pixel electrode 9 a and a TFT 30 are formed in each of a plurality of pixel regions arranged in a matrix that forms the image display region 10 a of the liquid crystal device 1. The TFT 30 is a pixel switching element that is electrically connected to the pixel electrode 9 a and performs switching control of the pixel electrode 9 a made of a transparent conductive film such as ITO during the operation of the liquid crystal device 1. 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 3a is electrically connected to the gate of the TFT 30, and the liquid crystal device 1 sequentially applies the scanning signals G1, G2,..., Gm to the scanning line 3a in a pulse sequence in this order at a predetermined timing. It is comprised so that it may apply. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,... Supplied from the data line 6a is closed by closing the switch of the TFT 30 serving as a switching element for a certain period. Sn is 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 contained in the liquid crystal layer 50 modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The transmittance with respect to light is increased, and light having a contrast corresponding to an image signal is emitted from the liquid crystal device 1 as a whole. In the storage capacitor 70, one capacitor electrode is electrically connected to the fixed potential line 300 and the other capacitor electrode is electrically connected to the pixel electrode 9a in order to prevent the image signal from leaking. . Such a storage capacitor 70 is added in parallel with a liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode.

<1-3: Specific Configuration of Pixel Unit>
A specific configuration of the pixel unit 72 will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view showing a partial configuration of the image display area 10a. 5 is a cross-sectional view taken along the line VV ′ of FIG. In FIG. 4, the components of the liquid crystal device 1 provided on the upper layer side of the light shielding film 25 and the lower layer side of the semiconductor layer 1a are not shown for convenience of explanation, and are adjacent to each other. Four matching pixel parts are shown.

  As shown in FIG. 4, on the TFT array substrate 10 of the liquid crystal device 1, a plurality of transparent pixel electrodes 9a (contours are indicated by dotted line portions 9a ′) in a matrix along each of the X direction and the Y direction. And data lines (not shown) and scanning lines 3a are provided along the vertical and horizontal boundaries of the pixel electrode 9a. Of the image display area 10a on the TFT array substrate 10, the area where the opaque lines such as the data lines and the scanning lines 3a extending vertically and horizontally, and the light shielding film 25 as an example of the “light shielding film” of the present invention are formed, This is a non-opening area in which light is not substantially transmitted in the image display area 10a. In addition, an area in which light contributing to image display can be transmitted among the pixel area is an opening area. The pixel switching TFT 30 is provided in each of the regions where the scanning line 3a and the data line overlapping the light shielding film 25 intersect each other.

  Of the scanning line 3a, a portion that is a part of the semiconductor layer 1a and overlaps with the channel region 1c indicated by the hatched region rising to the right in FIG. 4 is the gate electrode 3a2 of the TFT 30. The gate electrode 3a2 is formed by patterning a conductive film such as a metal film.

  The TFT 30 includes a semiconductor layer 1a extending along the Y direction that is the channel length direction. The semiconductor layer 1a is an example of the “semiconductor layer” in the present invention. The TFT 30 includes a gate electrode 3a2, a channel region 1c in the semiconductor layer 1a in which a channel is formed by an electric field from the scanning line 3a, a source region 1s and a drain region 1d provided on both sides of the channel region 1c, and a contact portion. 1f and 1g. The TFT 30 may have an LDD (Lightly Doped Drain) structure. According to the TF 30 having the LDD structure, the TFT 30 transistor can operate at high speed, and the display performance of the liquid crystal device 1 can be improved. The TFT 30 is electrically connected to the data line via a contact hole 81 electrically connected to the contact portion 1f, and the pixel electrode 9a via a contact hole 83 electrically connected to the contact portion 1g. Is electrically connected. Therefore, according to the TFT 30, it is possible to reliably supply the image signal to the pixel electrode 9a by switching control of the pixel portion by the TFT 30, and it is possible to display a high-quality image corresponding to the image signal.

  As shown in FIG. 5, the liquid crystal device 1 includes a light shielding film 11, an interlayer film 41, a semiconductor layer 1a, an interlayer film 42 including a convex portion 42a which is an example of the “convex portion” of the present invention, and the “light shielding film of the present invention. The light shielding film 25 and the interlayer film 43 are provided as an example.

  The light shielding film 11 is formed so as to protrude upward in the figure from the TFT array substrate 10. The light shielding film 11 shields light irradiated on the semiconductor layer 1a from the lower side of the semiconductor layer 1a. Therefore, according to the light shielding film 11, it is possible to reduce the light leakage current that may be generated in the semiconductor layer 1 a during the operation of the liquid crystal device 1. The interlayer film 41 is an insulating film formed on the light shielding film 11.

  The semiconductor layer 1a is formed by patterning a semiconductor film such as a polysilicon film formed on the interlayer film 41 into a predetermined shape.

  The convex portion 42a is formed in an island shape on the TFT array substrate 10 so as to cover the semiconductor layer 1a. The convex portion 42a is formed by partially removing the interlayer film 42, which is an insulating film formed on the semiconductor layer 1a, using a patterning method such as etching.

  The light shielding film 25 extends on each of the upper surface and the side surface of the convex portion 42a. The light shielding film 25 is formed by patterning the large size light shielding film so that the light shielding film 25 remains on the upper surface and the side surface of the convex portion 42a after a large size light shielding film is formed so as to extend to the convex portion 42a and its periphery. Alternatively, it may be formed on the upper surface and the side surface of the convex portion 42a using film formation such as CVD. The interlayer film 43 is formed on the light shielding film 25, and the pixel electrode 9a and the alignment film 16 are sequentially formed thereon.

  Therefore, according to the liquid crystal device 1 according to the present embodiment, the semiconductor layer 1a is covered with the light shielding film 25 from the upper side and the side surface side in three dimensions. Therefore, according to the liquid crystal device 1 according to the present embodiment, during the operation of the liquid crystal device 1, the light irradiated on the semiconductor layer 1 a from the upper surface and the side surface of the semiconductor layer 1 a from the TFT array substrate 10 is irradiated. The light shielding film 25 can surely shield the light. In addition, according to the liquid crystal device 1, compared with the case where the light shielding film 25 is formed flat along the substrate surface of the TFT array substrate 10, the light shielding property is reduced while reducing the area of the light shielding film 25 in plan view. Can be increased. More specifically, the width W2 (see FIGS. 4 and 5) of the non-opening region that separates the open regions of the pixel regions adjacent to each other among the plurality of pixel regions constituting the image display region 10a is shielded from light. Since it corresponds to the size of the film 25, the aperture ratio in the pixel region can be increased by reducing the planar area, that is, the size of the light shielding film 25 while improving the light shielding property.

  Therefore, according to the liquid crystal device 1 according to the present embodiment, it is possible to prevent the opening region narrowed by the light-shielding film from being narrowed as much as possible, to improve the display performance of the liquid crystal device 1, and to improve the semiconductor layer. The light leakage current can be reduced by improving the light shielding property against 1a.

  Further, as shown in FIG. 5, in the liquid crystal device 1, in particular, the distance T1 from the upper surface of the semiconductor layer 1a to the light shielding film 25 is larger than the distance W1 from the edge of the semiconductor layer 1a to the side surface of the convex portion 42a. At the time of manufacturing the liquid crystal device 1, the light shielding film 25 can be easily formed on the upper surface and side surfaces of the convex portion 42a so as to cover the semiconductor layer 1a.

<2: Manufacturing method of liquid crystal device>
Next, a manufacturing method of a liquid crystal device for manufacturing the liquid crystal device 1 will be described with reference to FIGS. 6 and 7 are process cross-sectional views sequentially showing main processes of the method of manufacturing the liquid crystal device according to the present embodiment.

  As shown in FIG. 6A, after the light shielding film 11 and the interlayer film 41 are formed in the region to be the image display region 10a on the TFT array substrate 10, the semiconductor layer 1a is formed thereon.

  Next, as shown in FIG. 6B, an interlayer film 42 is formed on the semiconductor layer 1a. Next, as shown in FIG. 7C, the interlayer film 42 is partially removed to form island-shaped protrusions 42a so as to cover the semiconductor layer 1a. More specifically, the interlayer film 42 is partially removed using a general-purpose patterning method such as a photolithography technique or an etching method to form the convex portion 42a. At this time, the interlayer film 42 is partially removed so that the distance T1 from the upper surface of the semiconductor layer 1a to the light shielding film 25 is larger than the distance W1 from the edge of the semiconductor layer 1a to the side surface of the convex portion 42a. By partially removing the interlayer film 42 in this way, the light shielding film 25 that covers the semiconductor layer 1a can be easily formed when the light shielding film 25 is formed on each of the upper surface and the side surface of the convex portion 42a in a later step. Can be formed.

  Next, as shown in FIG. 7D, the light shielding film 25 extending on the upper surface and the side surface of the convex portion 42a is formed by using a general-purpose film forming method such as a CVD method or a sputtering method. Thereafter, the liquid crystal device 1 is manufactured by sequentially forming the components of the liquid crystal device 1 provided on the upper layer side of the light shielding film 25.

  According to such a method for manufacturing a liquid crystal device, the light shielding film 25 can be formed so as not to narrow the opening region narrowed by the light shielding film 25 as much as possible, and the liquid crystal device 1 with improved display performance can be manufactured. In addition, it is possible to manufacture the liquid crystal device 1 in which the light leakage current is reduced by improving the light shielding property with respect to the semiconductor layer 1a.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 1c ... Channel region, 1s ... Source region, 1d ... Drain region, 1f, 1g ... Contact part, 3a2 ... Gate electrode, 10 ... TFT array Substrate, 20 ... counter substrate, 11, 25 ... light shielding film, 30 ... TFT, 41, 43 ... interlayer film, 42a ... convex part

Claims (6)

A semiconductor layer formed in a display region on the substrate;
A convex portion formed in an island shape so as to cover the semiconductor layer;
An electro-optical device comprising: a light-shielding film extending on each of an upper surface and a side surface of the convex portion. The electro-optical device according to claim 1, wherein a distance from an upper surface of the semiconductor layer to the light shielding film is larger than a distance from an edge of the semiconductor layer to the side surface. The semiconductor layer constitutes a part of a thin film transistor which is a switching element that controls switching of each of a plurality of pixel portions constituting the display region, and the thin film transistor separates an opening region in the display region from each other. The electro-optical device according to claim 1, wherein the electro-optical device is formed in a non-opening region. A first step of forming a semiconductor layer in a display region on a substrate;
A second step of forming a convex portion in an island shape so as to cover the semiconductor layer;
And a third step of forming a light-shielding film extending on each of an upper surface and a side surface of the convex portion. The second step includes a fourth step of forming an interlayer film on the semiconductor layer, and a fifth step of forming the convex portion by partially removing the interlayer film. The method of manufacturing an electro-optical device according to claim 4. In the fifth step, the interlayer film is partially removed so that a distance from an upper surface of the semiconductor layer to the light shielding film is larger than a distance from an edge of the semiconductor layer to the side surface. The method of manufacturing an electro-optical device according to claim 5.

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