JP2011059229A - Electro-optical device, method of manufacturing the same, and electric apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device and a method of manufacturing the same, capable of improving contrast and brightness using a simple process, and to provide an electric apparatus. <P>SOLUTION: The method of manufacturing the electro-optical device includes: a step of forming patterning of a first conductive film 9b on a substrate; a step of forming an insulating film 8b on the substrate and the first conductive film 9b; a step of subjecting the insulating film 8b to flattening processing and exposing an top surface of the first conductive film 9b from the insulating film 8b; and a step of forming a second conductive film 9 that is provided on the insulating film 8b so that the second conductive film 9 is overlapped with the top surface of the first conductive film 9b and electrically connected with the first conductive film 9b in plan view. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Among various electro-optical devices, in a liquid crystal device, an element substrate in which a pixel switching element such as a field effect transistor and an island-shaped pixel electrode are formed on a support substrate, and a counter substrate are disposed to face each other. A liquid crystal layer is held between the element substrate and the counter substrate. Among such electro-optical devices, in a reflection type electro-optical device in which a pixel electrode is formed of a light-reflective conductive film and an image is displayed in a reflection mode, the reflective pixel electrode is provided in order to ensure contrast and brightness. It is necessary to form as flat as possible. Among them, there is a risk that contrast and brightness may be reduced due to disorder of liquid crystal alignment and scattering of reflected light due to unevenness of a contact hole for connecting a pixel electrode and a lower drive element. On the other hand, for example, a method for realizing flattening by embedding a W plug or the like generally used in a semiconductor process has been proposed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-72799

  However, in the method described in Patent Document 1, a new facility for plug embedding is required and the process is somewhat complicated.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 Patterning and Forming a First Conductive Film on a Substrate, Forming an Insulating Film on the Substrate and the First Conductive Film, and Planarizing the Insulating Film And exposing the upper surface of the first conductive film to a second surface so as to overlap the upper surface of the first conductive film and to be electrically connected to the first conductive film in plan view. And a step of forming a conductive film.

  According to this, since the insulating film and the first conductive film can be flattened, an overlapping portion between the second conductive film and the first conductive film for connecting the underlying driving element without performing the plug process. Disclosed is a method for manufacturing an electro-optical device, which can suppress the disorder of liquid crystal alignment and the scattering of reflected light due to the unevenness, and can improve contrast and brightness through a simple process.

  Application Example 2 In the electro-optical device manufacturing method, the first conductive film is electrically connected to either a source region or a drain region of a transistor. Manufacturing method.

  According to this, when the direction of the current flowing through the transistor is reversed, the source and the drain are interchanged, but this can be easily handled.

  Application Example 3 A method for manufacturing an electro-optical device according to the above-described method, wherein the second conductive film is a pixel electrode.

  According to this, it is possible to suppress the disorder of the liquid crystal alignment and the scattering of the reflected light due to the unevenness of the overlapping portion between the pixel electrode and the first conductive film for connecting the transistor.

  Application Example 4 A method for manufacturing an electro-optical device according to the above-described method, wherein the planarization process is CMP and etch back.

  According to this, a high-speed and smooth polished surface can be obtained.

  Application Example 5 A plurality of first conductive films formed on a substrate, an insulating film disposed between the plurality of first conductive films, and the plurality of first conductive films formed on the insulating film And an area of the upper surface of the first conductive film is smaller than an area of the lower surface of the first conductive film, and the first conductive film is electrically connected to the first conductive film. An electro-optical device, wherein the upper surface of the insulating film and the upper surface of the insulating film are flush with each other.

  According to this, since the insulating film and the first conductive film can be flattened, an overlapping portion between the second conductive film and the first conductive film for connecting the underlying driving element without performing the plug process. Disclosed is an electro-optical device that can suppress the disorder of liquid crystal alignment and the scattering of reflected light due to the unevenness, and can improve contrast and brightness through a simple process.

  Application Example 6 In the electro-optical device, the first conductive film is electrically connected to either a source region or a drain region of a transistor.

  According to this, when the direction of the current flowing through the transistor is reversed, the source and the drain are interchanged, but this can be easily handled.

  Application Example 7 In the electro-optical device described above, the second conductive film is a pixel electrode.

  According to this, it is possible to suppress the disorder of the liquid crystal alignment and the scattering of the reflected light due to the unevenness of the overlapping portion between the pixel electrode and the first conductive film for connecting the transistor.

  Application Example 8 An electronic apparatus comprising the electro-optical device according to any one of the above.

  According to this, an electronic device that can improve contrast and brightness is provided.

1 is a block diagram illustrating an electrical configuration of a reflective electro-optical device according to an embodiment. FIGS. 4A and 4B are a plan view of the liquid crystal panel of the reflection type electro-optical device according to the present embodiment as viewed from the side of the counter substrate together with each component, and a cross-sectional view taken along the line H-H ′. (A) and (B) are each a plan view of adjacent pixels in the element substrate used in the reflective electro-optical device according to the present embodiment, and the element substrate cut at a position corresponding to the line AA ′. FIG. FIG. 10 is a process cross-sectional view illustrating the manufacturing method of the reflective electro-optical device according to the embodiment. Explanatory drawing of the electronic device using the reflection type electro-optical apparatus which concerns on this embodiment.

  The present embodiment will be described with reference to the drawings. In the drawings to be referred to in the following description, the scales of the layers and members are made different from each other in order to make each layer and each member recognizable on the drawing. Note that when the direction of the current flowing through the field effect transistor is reversed, the source and the drain are interchanged. However, in the following description, for convenience, the side to which the pixel electrode is connected is used as the drain and the data line is connected. The side will be described as a source.

(overall structure)
FIG. 1 is a block diagram showing an electrical configuration of the reflective electro-optical device according to this embodiment. As shown in FIG. 1, the reflective electro-optical device 100 includes a liquid crystal panel 100p, and the liquid crystal panel 100p includes a pixel region 10b in which a plurality of pixels 100a are arranged in a matrix in the central region. Yes. In the liquid crystal panel 100p, a plurality of data lines 6a and a plurality of scanning lines 3a extend vertically and horizontally inside the pixel region 10b on an element substrate 10 as a substrate described later, and positions corresponding to the intersections thereof. A pixel 100a is formed. In each of the plurality of pixels 100a, a field effect transistor 30 as a pixel switching element and a pixel electrode 9 as a second conductive film described later are formed. The data line 6 a is electrically connected to the source of the field effect transistor 30, the scanning line 3 a is electrically connected to the gate of the field effect transistor 30, and the pixel electrode is connected to the drain of the field effect transistor 30. 9 is electrically connected.

  In the element substrate 10, a scanning line driving circuit 104 and a data line driving circuit 101 are configured outside the pixel region 10 b. The data line driving circuit 101 is electrically connected to one end of each data line 6a, and sequentially supplies the image signal supplied from the image processing circuit to each data line 6a. The scanning line driving circuit 104 is electrically connected to each scanning line 3a, and sequentially supplies a scanning signal to each scanning line 3a.

  In each pixel 100a, the pixel electrode 9 is opposed to a common electrode formed on a counter substrate, which will be described later, via a liquid crystal, and constitutes a liquid crystal capacitor 50a. In addition, a holding capacitor 60 is added to each pixel 100a in parallel with the liquid crystal capacitor 50a in order to prevent fluctuation of an image signal held in the liquid crystal capacitor 50a. In the present embodiment, in order to configure the storage capacitor 60, the capacitor line 3b extending in parallel with the scanning line 3a across the plurality of pixels 100a is formed.

(Configuration of liquid crystal panel and element substrate)
2A and 2B are a plan view of the liquid crystal panel 100p of the reflection type electro-optical device 100 according to the present embodiment as viewed from the side of the counter substrate together with each component, and a cross-sectional view thereof taken along line HH ′. It is. As shown in FIGS. 2A and 2B, in the liquid crystal panel 100p of the reflective electro-optical device 100, the element substrate 10 and the counter substrate 20 are connected to each other with a sealant 107 through a predetermined gap. The sealing material 107 is disposed along the edge of the counter substrate 20. The sealing material 107 is an adhesive made of a photo-curing resin, a thermosetting resin, or the like, and is mixed with a gap material such as glass fiber or glass beads for setting the distance between both substrates to a predetermined value. In the present embodiment, the support substrate of the element substrate 10 is a translucent substrate 10d, and the support substrate of the counter substrate 20 is a similar translucent substrate 20d.

  In the element substrate 10, the data line driving circuit 101 and the plurality of terminals 102 are formed along one side of the element substrate 10 in the outer region of the sealant 107, and the scanning line is formed along another side adjacent to the one side. A drive circuit 104 is formed. Further, at least one corner of the counter substrate 20 is formed with a vertical conductive material 109 for electrical conduction between the element substrate 10 and the counter substrate 20.

  As will be described in detail later, on the element substrate 10, light reflective pixel electrodes 9 (light reflective layers) are formed in a matrix. On the other hand, a frame 108 made of a light-shielding material is formed in the inner area of the sealing material 107 on the counter substrate 20, and the inner side is an image display area 10 a. A common electrode 21 made of an ITO (Indium Tin Oxide) film is formed on the counter substrate 20. Note that a light shielding film (not shown) called a black matrix or a black stripe may be formed on the counter substrate 20 at a position facing between the pixel electrodes 9. In addition, in the pixel area 10b, a dummy pixel may be configured in an area overlapping with the frame 108. In this case, an area excluding the dummy pixel in the pixel area 10b is used as the image display area 10a. become.

  In the reflection type electro-optical device 100 formed in this way, the light incident from the counter substrate 20 side is reflected by the pixel electrode 9 and again emitted from the counter substrate 20 side by the liquid crystal layer 50 for each pixel. As a result of the light modulation, an image is displayed. Here, the reflective electro-optical device 100 can be used as a color display device of an electronic device such as a mobile computer or a mobile phone. In this case, the counter substrate 20 is provided with a color filter (not shown) or a protective film. It is formed. Further, on the surface of the counter substrate 20 on the light incident side, the type of the liquid crystal layer 50 to be used, that is, an operation mode such as a TN (twisted nematic) mode, an STN (super TN) mode, or a normally white mode / normally. Depending on the black mode, a polarizing film, a retardation film, a polarizing plate and the like are arranged in a predetermined direction. Further, the reflective electro-optical device 100 can be used as a light valve for RGB in a projection display device (liquid crystal projector) described later. In this case, each of the RGB reflective electro-optical devices 100 receives light of each color separated through RGB color separation dichroic mirrors as projection light. Not formed.

(Configuration of each pixel)
3A and 3B are respectively a plan view of adjacent pixels in the element substrate 10 used in the reflective electro-optical device 100 according to the present embodiment, and a position corresponding to the line AA ′. It is sectional drawing when the element substrate 10 is cut | disconnected. 3A, the pixel electrode 9 is indicated by a long dotted line, the data line 6a is indicated by an alternate long and short dash line, the scanning line 3a and the capacitor line 3b are indicated by solid lines, and the semiconductor layer 1a is indicated by a short and thin dotted line. It is shown. A plurality of dots are attached to the gap 9s between adjacent pixel electrodes 9.

  As shown in FIGS. 3A and 3B, the element substrate 10 includes a first surface 10x and a second surface 10y of a translucent substrate 10d (support substrate) made of a quartz substrate, a glass substrate, or the like. A transparent base insulating layer 15 made of a silicon oxide film or the like is formed on the first surface 10x located on the counter substrate 20 side, and an N-channel type electric field is formed on the upper layer side so as to overlap with the pixel electrode 9. An effect transistor 30 is formed. The field effect transistor 30 includes a channel region 1g, a low-concentration source region 1b, a high-concentration source region 1d, and a low-concentration drain with respect to an island-shaped polysilicon film or a semiconductor layer 1a made of an island-shaped single crystal semiconductor layer. It has an LDD structure in which a region 1c and a high concentration drain region 1e are formed. A translucent gate insulating layer 2 made of a silicon oxide film is formed on the surface side of the semiconductor layer 1a, and a gate electrode (scanning line) made of a metal film or a doped silicon film is formed on the surface of the gate insulating layer 2. 3a) is formed. In addition, the capacitor line 3b is opposed to the portion extending from the high concentration drain region 1e in the semiconductor layer 1a with the gate insulating layer 2 interposed therebetween, and a storage capacitor 60 is formed. In the present embodiment, the field effect transistor 30 has an LDD (Lightly Doped Drain) structure, but has a structure in which a high concentration source region and a high concentration drain region are formed in a self-aligned manner on the scanning line 3a. It may be adopted. In the present embodiment, the gate insulating layer 2 is made of a silicon oxide film formed by thermal oxidation, but a silicon oxide film or silicon nitride film formed by a CVD method or the like can also be used.

  On the upper layer side of the field effect transistor 30, interlayer insulating films 7 and 8 made of a translucent insulating film such as a silicon oxide film are formed. A data line 6 a made of a metal film or a doped silicon film is formed on the surface of the interlayer insulating film 7. The data line 6 a is electrically connected to the high concentration source region 1 d through a contact hole 7 a formed in the interlayer insulating film 7. Connected. A first conductive pattern 9 a made of a metal film or the like is formed on the surface of the interlayer insulating film 7, and the first conductive pattern 9 a is connected to the high concentration drain region 1 e through a contact hole 7 b formed in the interlayer insulating film 7. Is electrically connected.

  A second conductive pattern 9b as a first conductive film made of a metal film or the like is formed on the surface of the first conductive pattern 9a. The area of the upper surface of the second conductive pattern 9b is smaller than the area of the lower surface of the second conductive pattern 9b.

  On the surface of the interlayer insulating film 8, a light-reflective pixel electrode 9 (reflective layer) made of a single aluminum film, an aluminum alloy film, a single silver film, a silver alloy film, or a laminated film thereof is formed. Are electrically connected to the high-concentration drain region 1e through the first and second conductive patterns 9a and 9b formed in the interlayer insulating film 8. The upper surface of the second conductive pattern 9b and the upper surface of the interlayer insulating film 8 are flush with each other. An alignment film 16 is formed on the pixel electrode 9.

  The element substrate 10 configured as described above is disposed so as to face the counter substrate 20 so that the pixel electrode 9 and the common electrode 21 face each other, and between these substrates is in a space surrounded by the sealing material 107. A liquid crystal layer 50 as an electro-optical material is enclosed. The liquid crystal layer 50 takes a predetermined alignment state by the alignment films 16 and 26 formed on the element substrate 10 and the counter substrate 20 in a state where an electric field from the pixel electrode 9 is not applied. The liquid crystal layer 50 is made of, for example, one or a mixture of several types of nematic liquid crystals.

(Measures for flattening the pixel electrode 9)
In the reflective electro-optical device 100 configured as described above, in the element substrate 10, island-shaped pixel electrodes 9 are formed on the surface of the interlayer insulating film 8. However, in the present embodiment, the surface of the second conductive pattern 9b connected to the drain of the field effect transistor 30 is exposed by the planarization process of the interlayer insulating film 8, and this is used as a contact to connect the pixel electrode 9. ing. Therefore, the second conductive pattern 9b and the interlayer insulating film 8 are polished so as to be flush with each other, and the surface of the pixel electrode 9 provided in the upper layer portion thereof is flat.

(Manufacturing method of the reflective electro-optical device 100)
Hereinafter, of the manufacturing process of the reflective electro-optical device 100, processes after the formation of the interlayer insulating film 7 will be described. FIG. 4 is a process cross-sectional view illustrating the manufacturing method of the reflective electro-optical device 100 according to the present embodiment.

  First, as shown in FIG. 4A, the silicon oxide is formed so as to cover the field effect transistor 30 and the like on the surface side of the element substrate 10 (the first surface 10x of the translucent substrate 10d (support substrate)). After the interlayer insulating film 7 is formed by, for example, contact holes 7a and 7b are formed in the interlayer insulating film 7 by using a photolithography technique and an etching technique, and the data line 6a and the first conductive layer are formed on the upper side of the interlayer insulating film 7. A pattern 9a is formed.

  Next, as shown in FIG. 4B, a second conductive pattern 9b is formed on the upper layer side of the first conductive pattern 9a.

  Next, as shown in FIG. 4C, the insulating film 8b is covered with silicon oxide or the like so as to cover the data line 6a, the first conductive pattern 9a, and the second conductive pattern 9b on the surface of the interlayer insulating film 7. Form. At this time, the insulating film 8b is made thicker than the height of the second conductive pattern 9b.

  Next, as shown in FIG. 4D, the insulating film 8b is polished from the surface. Such polishing is performed until the second conductive pattern 9b is exposed. In the present embodiment, the time when the second conductive pattern 9b is exposed is defined as the polishing end point. As such a polishing process, chemical mechanical polishing (CMP) can be used. In such chemical mechanical polishing, the action of chemical components contained in the polishing liquid and the relative movement between the polishing agent and the translucent substrate 10d are smooth at high speed. A polished surface can be obtained. More specifically, in a polishing apparatus, while relatively rotating a surface plate on which a polishing cloth (pad) made of nonwoven fabric, foamed polyurethane, porous fluororesin, or the like is attached, and a holder that holds the translucent substrate 10d. Polish. At that time, for example, an abrasive containing cerium oxide particles having an average particle diameter of 0.01 to 20 μm, an acrylate derivative as a dispersant, and water is supplied between the polishing cloth and the translucent substrate 10d. The insulating film 8b can also be removed by performing etch back after performing chemical mechanical polishing. The interlayer insulating film 8 is formed by the insulating film 8b.

  Next, as shown in FIG. 4E, a single aluminum film, an aluminum alloy film, a single silver film, a silver alloy film, or a laminated film thereof is formed on the upper side of the interlayer insulating film 8 including the second conductive patterns 9b. The pixel electrode 9 made of is formed in an island shape.

  Thereafter, the alignment film 16 is formed to obtain the element substrate 10. In such an element substrate 10, the portion overlapping the second conductive pattern 9 b of the pixel electrode 9 can be flattened without performing a plug process, so that contrast and brightness can be improved with a simple process. become.

[Other Embodiments]
In the above embodiment, the film thickness of the insulating film 8b is thicker than the height dimension of the second conductive pattern 9b. However, the film thickness of the insulating film 8b may be thinner than the height dimension of the second conductive pattern 9b. . In this case, in the polishing step, the surface of the insulating film 8b may be polished by polishing for a predetermined time after the second conductive pattern 9b is exposed.

  In the above-described embodiment, the present embodiment is applied to the production of the reflection type electro-optical device. However, the present embodiment may be applied to the production of the transmission type electro-optical device. A pixel electrode is formed by the conductive film. Even in such a transmission type electro-optical device, if this embodiment is applied, the portion overlapping the second conductive pattern 9b of the pixel electrode 9 can be flattened without performing the plug process, and therefore, with a simple process. It will be possible to improve the contrast and brightness.

[Example of mounting on electronic devices]
The reflective electro-optical device 100 according to this embodiment is used in a projection display device (liquid crystal projector / electronic device) shown in FIG. 5A and a portable electronic device shown in FIGS. 5B and 5C. be able to.

  A projection display apparatus 1000 shown in FIG. 5A includes a polarization illumination apparatus 800 including a light source unit 810, an integrator lens 820, and a polarization conversion element 830 arranged along the system optical axis L, and the polarization illumination apparatus 800. The polarization beam splitter 840 that reflects the S-polarized light beam emitted from the S-polarized light beam reflection surface 841 and the blue light (B) component of the light reflected from the S-polarized light beam reflection surface 841 of the polarization beam splitter 840. It has a dichroic mirror 842 that separates, and a dichroic mirror 843 that reflects and separates the red light (R) component of the luminous flux after the blue light is separated. The projection display apparatus 1000 includes three reflective electro-optical devices 100 (reflective electro-optical devices 100R, 100G, and 100B) on which each color light is incident. Further, the projection display apparatus 1000 combines the light modulated by the three reflective electro-optical devices 100R, 100G, and 100B by the dichroic mirrors 842 and 843 and the polarization beam splitter 840, and then combines the combined light with the projection lens. The image is projected onto the screen 860 via 850.

  A cellular phone 3000 illustrated in FIG. 5B includes a plurality of operation buttons 3001, scroll buttons 3002, and the reflective electro-optical device 100 as a display unit. By operating the scroll button 3002, the screen displayed on the reflective electro-optical device 100 is scrolled. A personal digital assistant (PDA) 4000 shown in FIG. 5C includes a plurality of operation buttons 4001, a power switch 4002, and the reflective electro-optical device 100 as a display unit. When operated, various types of information such as an address book and a schedule book are displayed on the reflective electro-optical device 100.

  Furthermore, if a color filter is formed on the counter substrate 20 or the like, the reflective electro-optical device 100 capable of color display can be formed. In addition, if the reflective electro-optical device 100 in which a color filter is formed is used, a single-plate projection display device can be configured.

  DESCRIPTION OF SYMBOLS 1a ... Semiconductor layer 1b ... Low concentration source region 1c ... Low concentration drain region 1d ... High concentration source region 1e ... High concentration drain region 1g ... Channel region 2 ... Gate insulating layer 3a ... Scan line 3b ... Capacitance line 6a ... Data line 7 , 8 ... Interlayer insulating film 7a, 7b ... Contact hole 8b ... Insulating film 9 ... Pixel electrode (reflection layer) (second conductive film) 9a ... First conductive pattern 9b ... Second conductive pattern (first conductive film) 9s ... Gap 10 ... Element substrate (substrate) 10a ... Image display region 10b ... Pixel region 10d ... Translucent substrate (support substrate) 10x ... First surface 10y ... Second surface 15 ... Underlying insulating layers 16, 26 ... Alignment film 20 ... Counter substrate 20d ... Translucent substrate 21 ... Common electrode 30 ... Field-effect transistor 50 ... Liquid crystal layer (electro-optic material) 50a ... Liquid crystal capacitance 60 ... Retention capacitance DESCRIPTION OF SYMBOLS 100,100R, 100G, 100B ... Reflective electro-optical device 100a ... Pixel 100p ... Liquid crystal panel 101 ... Data line drive circuit 102 ... Terminal 104 ... Scanning line drive circuit 107 ... Sealing material 108 ... Frame 109 ... Vertical conduction material 800 ... Polarization Illuminating device 810: Light source unit 820 ... Integrator lens 830 ... Polarization conversion element 840 ... Polarizing beam splitter 841 ... S-polarized light beam reflecting surface 842, 843 ... Dichroic mirror 850 ... Projection lens 860 ... Screen 1000 ... Projection type display device 3000 ... Mobile phone 3001, 4001 ... Operation buttons 3002 ... Scroll buttons 4002 ... Power switch.

Claims (8)

Patterning and forming a first conductive film on a substrate;
Forming an insulating film on the substrate and the first conductive film;
Planarizing the insulating film to expose an upper surface of the first conductive film from the insulating film;
Forming a second conductive film on the insulating film so as to overlap the upper surface of the first conductive film in plan view and to be electrically connected to the first conductive film;
A method for manufacturing an electro-optical device. The method of manufacturing the electro-optical device according to claim 1,
The method of manufacturing an electro-optical device, wherein the first conductive film is electrically connected to either a source region or a drain region of a transistor. The method of manufacturing an electro-optical device according to claim 1 or 2,
The method of manufacturing an electro-optical device, wherein the second conductive film is a pixel electrode. In the manufacturing method of the electro-optical device according to any one of claims 1 to 3,
The method of manufacturing an electro-optical device, wherein the planarization treatment is CMP and etch back. A plurality of first conductive films formed on the substrate;
An insulating film disposed between the plurality of first conductive films;
A second conductive film formed on the insulating film and electrically connected to one of the plurality of first conductive films;
Have
The area of the upper surface of the first conductive film is smaller than the area of the lower surface of the first conductive film,
An electro-optical device, wherein an upper surface of the first conductive film and an upper surface of the insulating film are flush with each other. The electro-optical device according to claim 5.
The electro-optical device, wherein the first conductive film is electrically connected to either a source region or a drain region of a transistor. The electro-optical device according to claim 5 or 6,
The electro-optical device, wherein the second conductive film is a pixel electrode.   An electronic apparatus comprising the electro-optical device according to claim 5.