Light-emitting display device

Abstract

In a pixel equipped with a thin-film transistor using an oxide semiconductor, improvement of aperture ratio One of the objectives is to provide a light-emitting display device that can measure [the required level of light]. [Solution] The system has a plurality of pixels having thin-film transistors and light-emitting elements, and the pixels are scanned The thin-film transistor is electrically connected to a first wiring that functions as a line, and the first wiring The line has an oxide semiconductor layer provided via a gate insulating film, and the oxide semiconductor layer is first The wiring extends beyond the area where it is provided, and the light-emitting element and the oxide semiconductor layer overlap. It is laid out like a tatami mat.

Description

Technical Field

[0001] The present invention relates to a light-emitting display device. It also relates to an electronic device including the light-emitting display device.

Background Art

[0002] Thin film transistors formed on a flat plate such as a glass substrate, as typified by liquid crystal display devices, are made of amorphous silicon or polycrystalline silicon. Although thin film transistors using amorphous silicon have a low field-effect mobility, they can cope with the enlargement of the area of the glass substrate. On the other hand, thin film transistors using crystalline silicon have a high field-effect mobility, but require a crystallization process such as laser annealing and do not necessarily suit the enlargement of the area of the glass substrate. On the other hand, a technique of manufacturing a thin film transistor using an oxide semiconductor and applying it to an electronic device or an optoelectronic device

[0003] has attracted attention. For example, Patent Document 1 discloses a technique of manufacturing a thin film transistor using zinc oxide or an In-Ga-Zn-O-based oxide semiconductor as an oxide semiconductor film and using it for a switching element of a light-emitting display device.

Prior Art Documents

Patent Documents

Patent Document 1

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A thin film transistor using an oxide semiconductor in the channel region has a channel made of amorphous silicon Higher field-effect mobility is obtained compared to thin-film transistors used in the Nell region. A pixel comprising a thin-film transistor formed using an oxide semiconductor is used in an EL display. Applications in light-emitting display devices such as 3D displays and 4K2K displays are expected. In light-emitting display devices with further added value, such as those mentioned above, the area per pixel becomes smaller. While this is expected, there is a demand for light-emitting display devices with pixels that have an improved aperture ratio.

[0006] Therefore, the present invention relates to a pixel comprising a thin-film transistor using an oxide semiconductor, One of the objectives is to provide a light-emitting display device that can improve the output rate. [Means for solving the problem]

[0007] One aspect of the present invention has a plurality of pixels having a thin film transistor and an light-emitting element, the pixels The thin-film transistor is electrically connected to the first wiring which functions as a scan line, and the second The wiring has an oxide semiconductor layer provided on it via a gate insulating film, and the oxide semiconductor layer is The first wiring extends beyond the region where it is provided, and includes a light-emitting element and an oxide semiconductor layer. This is a light-emitting display device in which two elements are superimposed.

[0008] One aspect of the present invention has a plurality of pixels having a thin film transistor and an light-emitting element, the pixels It is electrically connected to a first wire that functions as a scan line and a second wire that functions as a signal line. The thin-film transistor is provided with an oxide film on the first wiring via a gate insulating film. The material has a semiconductor layer, and the oxide semiconductor layer extends beyond the region where the first wiring is provided. The second wiring extends over the gate insulating film on the first wiring and contacts the oxide semiconductor layer. It is a light-emitting display device in which a light-emitting element and an oxide semiconductor layer are provided so as to overlap each other.

[0009] One aspect of the present invention has a plurality of pixels having a thin-film transistor and a light-emitting element, and the pixels are electrically connected to a first wiring functioning as a scanning line and a second wiring functioning as a signal line and the thin-film transistor has an oxide semiconductor layer provided via a gate insulating film on the first wiring and the oxide semiconductor layer is provided so as to protrude from the region where the first wiring is provided and the second wiring extends on the gate insulating film on the first wiring and an interlayer insulating film on the gate insulating film and contacts the oxide semiconductor layer, and it is a light-emitting display device in which a light-emitting element and an oxide semiconductor layer are provided so as to overlap each other.

[0010] One aspect of the present invention has a plurality of pixels having a first thin-film transistor, a second thin-film transistor, and a light-emitting element, and the pixels are electrically connected to a first wiring functioning as a scanning line and a second wiring functioning as a signal line and the first thin-film transistor has an oxide semiconductor layer provided via a gate insulating film on the first wiring and the oxide semiconductor layer is provided so as to protrude from the region where the first wiring is provided and the second wiring extends on the gate insulating film on the first wiring and contacts the oxide semiconductor layer, and a third wiring for making an electrical connection between the oxide semiconductor layer and the first thin-film transistor and the second thin-film transistor is provided by extending on the gate insulating film on the first wiring <�000084>and it is a light-emitting display device in which a light-emitting element and an oxide semiconductor layer are provided so as to overlap each other. and it is a light-emitting display device in which a light-emitting element and an oxide semiconductor layer are provided so as to overlap each other.

[0011] One aspect of the present invention has a plurality of pixels having a thin-film transistor and a light-emitting element, and the pixels is electrically connected to a first wiring that functions as a scanning line and a second wiring that functions as a signal line The thin film transistor is provided with an oxide semiconductor layer provided via a gate insulating film on the first wiring The oxide semiconductor layer extends beyond the region where the first wiring is provided The second wiring extends on the gate insulating film on the first wiring and the interlayer insulating film on the gate insulating film and contacts the oxide semiconductor layer The third wiring that contacts the oxide semiconductor layer and makes an electrical connection between the first thin film transistor and the second thin film transistor extends on the gate insulating film on the first wiring and the interlayer insulating film on the gate insulating film A light-emitting display device is provided in which a light-emitting element and an oxide semiconductor layer are superimposed on the gate insulating film on the first wiring and the interlayer insulating film on the gate insulating film

Effect of the Invention

[0012] Therefore, a light-emitting display device having a high-definition display section can be obtained

Brief Description of the Drawings

[0013] [Figure 1] Cross-sectional view for explaining the light-emitting display device [Figure 2] Top view for explaining the light-emitting display device [Figure 3] Top view and cross-sectional view for explaining the light-emitting display device \> [Figure 4] Top view for explaining the light-emitting display device [Figure 5] Top view and cross-sectional view for explaining the light-emitting display device [Figure 6] Top view for explaining the light-emitting display device [Figure 7] Circuit diagram for explaining the light-emitting display device [Figure 8] Circuit diagram for explaining the light-emitting display device [Figure 9] A cross-sectional view illustrating a light-emitting device. [Figure 10] A diagram explaining electronic devices. [Figure 11] A diagram explaining electronic devices. [Figure 12] A top view and a cross-sectional view illustrating a light-emitting device. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention will not be described in the following description. The present invention is not limited to, and its form and details may vary without departing from the spirit and scope of the present invention. Those skilled in the art will readily understand that this can be changed. Therefore, the present invention can be implemented as follows: The description of the form is not to be interpreted as being limited to the content of the description. Furthermore, the structure of the present invention described below In the design, the same reference numeral is used for identical parts or parts with similar functions across different drawings. It is used in this way, and the explanation of its repetition is omitted.

[0015] In each figure described herein, the size of each component, the thickness of the layer, or the area is clearly indicated. It may be exaggerated for illustrative purposes. Therefore, it is not necessarily limited to that scale.

[0016] Furthermore, the terms "1st," "2nd," "3rd," etc. used in this specification are used to avoid confusion of constituent elements. This is attached to the number and does not limit it numerically. Therefore, for example, "the first" can be written as " This can be explained by appropriately replacing it with "the second" or "the third," etc.

[0017] (Embodiment 1) In this embodiment, as an example, a thin-film transistor (hereinafter also referred to as TFT) and the T This section describes a pixel having a light-emitting element connected to the FT, and explains the light-emitting display device. A pixel is an element provided in each pixel of a display device, such as a thin-film transistor or light-emitting element. This refers to a group of elements that control the display using electrical signals such as wiring. This refers to the following. Note that pixels may include color filters, etc., and each pixel may, It can also be considered as one color element that can control brightness. Therefore, as an example, the RGB color elements In the case of a color display device, the smallest unit of an image is a pixel with red (R) and a pixel with green (G) and a pixel with blue (B). It consists of three pixels, and an image can be obtained using multiple pixels. Yes.

[0018] The light-emitting element has a configuration in which a light-emitting layer is provided between a pair of electrodes (anode and cathode), and on the electrodes It is formed by stacking elements that constitute the light-emitting layer. In this specification, one electrode of the light-emitting element is shown in the figure. In some contexts, it is referred to as a light-emitting element.

[0019] Furthermore, when it is stated that A and B are connected, it means that A and B are electrically connected. This includes the case where A and B are connected, and the case where A and B are directly connected. Here, A and B are It is defined as an object that has an electrical effect. Specifically, this includes transistors and other transistors. A and B are connected via a switching element, and the conduction of the switching element causes A and B to be connected. When B and A are at approximately the same potential, or when A and B are connected via a resistive element, both of the resistive elements If the potential difference generated at the ends is such that it does not affect the operation of the circuit including A and B, However, when considering the circuit operation, it is acceptable to treat the part between A and B as the same node. This indicates a state where something is in a particular condition.

[0020] Figure 1(A) shows a top view of a pixel. Note that the structure of the TFT shown in Figure 1(A) is a bottom view. It has a gate-type structure, and the oxide semiconductor layer that forms the channel region is opposite the gate wiring. A so-called inverted staggered type, having a wiring layer on one side that serves as the source and drain electrodes of the TFT. This shows the configuration.

[0021] Pixel 100 shown in Figure 1(A) is a first wiring 101A that functions as a scan line, and a signal line. The second wiring 102A, the first oxide semiconductor layer 103A, and the second oxide semiconductor layer function together. It has 103B, a power line 104A, a capacitive electrode 101B, and a light-emitting element 105. Also, Figure 1(A The pixel 100 shown in the diagram electrically connects the first oxide semiconductor layer 103A and the capacitive electrode 101B. A third wire 102B for connection is provided, and the first thin-film transistor 107A is formed. Furthermore, the pixel 100 shown in Figure 1(A) consists of a second oxide semiconductor layer 103B and a light-emitting element 10 5 has a fourth wiring 104B for electrically connecting to the second thin-film transistor 10 7B is formed.

[0022] First wiring 101A, second wiring 102A, third wiring 102B, fourth wiring 104B, The first oxide semiconductor layer 103A, the second oxide semiconductor layer 103B, the power line 104A, and A partition wall 106 is provided on the capacitive electrode 101B to separate the light-emitting elements for each pixel. Furthermore, a light-emitting element 105 connected to the fourth wiring 104B is provided inside the partition wall 106. And so it becomes.

[0023] The first wiring 101A is also a wiring that functions as the gate of the first thin-film transistor 107A. Yes. Capacitive electrode 101B is the gate of the second thin-film transistor 107B, and one of the capacitive elements. It is also a wiring that functions as an electrode. The second wiring 102A is connected to the first thin-film transistor. It is also a wire that functions as either the source or drain electrode of the 107A. Line 102B is the other of the source electrode or drain electrode of the first thin-film transistor 107A. It is also a wiring that functions as a second thin-film transistor 107B. Power line 104A is the second thin-film transistor 107B Even wiring that functions as one of the electrodes (either a drain electrode or a capacitive element) and the other electrode of a capacitive element. Yes. The fourth wire 104B is the source electrode or drain of the second thin-film transistor 107B. This wiring also functions as the other side of the input electrode.

[0024] The first wiring 101A and the capacitive electrode 101B are provided from the same layer, and the second wiring 102 A, the third wiring 102B, the power line 104A, and the fourth wiring 104B are provided from the same layer. Furthermore, the power line 104A and the capacitive electrode 101B are provided in a partially overlapping manner, and the second This forms the retention capacitance of thin-film transistor 107B.

[0025] Furthermore, the first oxide semiconductor layer 103A of the first thin-film transistor 107A is the first It is provided on the wiring 101A via a gate insulating film (not shown). The conductor layer 103A extends beyond the area where the first wiring 101A is provided and beyond the partition wall 106. It is being done.

[0026] Note that when A protrudes beyond B, if we look at the top view focusing on the stacked A and B, then A This refers to a situation where the ends of B do not coincide, and A extends outward beyond the end of B.

[0027] In addition to the first thin-film transistor 107A and the second thin-film transistor 107B, several The configuration may also include a thin-film transistor. The first thin-film transistor 107A is , and has a function for selecting a pixel that is equipped with the first thin-film transistor 107A. Also called a selector transistor. The second thin-film transistor 107B is the second thin-film transistor. It has a function for controlling the current flowing to the light-emitting element 105 of the pixel having a converter 107B. Also called a drive transistor.

[0028] Figure 1(B) also shows the cross-sections between the dashed lines A-A', B-B', and C-C' in Figure 1(A). The surface structure is shown. In the cross-sectional structure shown in Figure 1(B), the substrate 111 has a base film 1 A first wiring 101A, which is a gate, and a capacitive electrode 101B are provided via 12. A gate insulating film 113 is provided so as to cover the first wiring 101A and the capacitive electrode 101B. On the gate insulating film 113, there is a first oxide semiconductor layer 103A and a second oxide semiconductor layer A conductive layer 103B is provided. A second wiring 1 is provided on the first oxide semiconductor layer 103A. On the third wiring 102B and the second oxide semiconductor layer 103B, there is a power line 104A. A fourth wiring 104B is provided. Also, the first oxide semiconductor layer 103A and the second acid The ionized semiconductor layer 103B, the second wiring 102A, the third wiring 102B, the power line 104A, and On the fourth wiring 104B, there is an oxide insulating layer 114 that functions as a passivation film. It is provided. First wiring 101A, second wiring 102A, third wiring 102B, fourth Wiring 104B, first oxide semiconductor layer 103A, second oxide semiconductor layer 103B, power supply A partition wall 106 is provided on the oxide insulating layer 114 on wire 104A and capacitive electrode 101B. Furthermore, an opening is formed in the oxide insulating layer 114 on the fourth wiring 104B. At the opening, the electrodes of the light-emitting element 105 are connected to the fourth wiring 104B. In the dashed line B-B', the third wiring 102B and the capacitive electrode 101B are connected by a gate insulating film. It is connected through an opening formed in 113.

[0029] Note that the pixels shown in Figures 1(A) and 1(B) are multiple pixels 701 on the substrate 700 shown in Figure 7. As shown, they are arranged in a matrix. In Figure 7, the pixel section 7 is on the substrate 700. 02. A configuration having a scan line drive circuit 703 and a signal line drive circuit 704 is shown. The pixel 701 is powered by a first wiring 101A connected to the scan line drive circuit 703. The scanning signal determines whether each row is selected or not. Pixel 701, selected by the number, is connected to a second wiring that is connected to the signal line drive circuit 704. 102A supplies the video voltage (also called the image signal, video signal, or video data). Furthermore, the pixel 701 extends from the power supply circuit 705 located outside the substrate 700. It is connected to power line 104A provided therein.

[0030] In Figure 7, the scan line drive circuit 703 and the signal line drive circuit 704 are provided on the substrate 700. Although the configuration has been shown, either the scan line drive circuit 703 or the signal line drive circuit 704 The configuration may be such that the elements are provided on the substrate 700. Alternatively, only the pixel section 702 may be provided on the substrate 700. This configuration is also acceptable. In Figure 7, the power supply circuit 705 is provided outside the circuit board 700. Although the configuration is shown, it may also be configured to be mounted on a circuit board 700.

[0031] In Figure 7, the pixel section 702 has multiple pixels 701 arranged in a matrix (stripe arrangement). An example is shown. Note that pixel 701 is not necessarily arranged in a matrix. It is not necessary; for example, pixel 701 may be arranged in a delta configuration or a Bayer configuration. The display method used in the element 702 is either progressive or interlaced. It is possible to do so. Furthermore, the color elements controlled by pixels when displaying color are RGB( It is not limited to three colors (R is red, G is green, B is blue), but can be more than that, for example, RGBW( W is white), or RGB with one or more additional colors such as yellow, cyan, or magenta. There is a possibility that the size of the display area for each dot of the color element may differ.

[0032] In Figure 7, the first wiring 101A, the second wiring 102A, and the power line 104A are for the pixel This is shown according to the number in the row and column directions. Note that the first wiring 101A and the second wiring 10 2A and power line 104A are used for subpixels (also called secondary pixels or sub-pixels) that make up a pixel. The number of lines may be increased depending on the number of ) or the number of transistors within the pixel. The first wiring 101A, the second wiring 102A, and the power line 104A are shared between the pixels. It can also be configured to drive the basic 701.

[0033] Note that in Figure 1(A), the shape of the TFT is shown assuming that the second wiring 102A is rectangular. However, the shape surrounding the third wiring 102B (specifically, U-shaped or C-shaped) is as follows: The configuration may also be designed to increase the area of ​​the region where the carrier moves, thereby increasing the amount of current flowing.

[0034] Furthermore, the width of the first wiring 101A other than the region that becomes the first thin-film transistor 107A is It may be made smaller so that it becomes thinner in parts. By reducing the width of the first wiring, the pixels This can improve the aperture ratio.

[0035] The aperture ratio represents the area of ​​light that is transmitted per unit area. As the area occupied by the light-impermeable material increases, the aperture ratio decreases, and the light-transmitting material... As the area occupied increases, the aperture ratio improves. In light-emitting display devices, inside the partition wall Ensure that no light-impermeable wiring or other objects overlap the area occupied by the light-emitting element. Reducing the size of thin-film transistors improves the aperture ratio.

[0036] Furthermore, a thin-film transistor has at least three components, including a gate, a drain, and a source. It is an element having terminals, and has a channel region between the drain region and the source region. Current can be passed through the drain region, channel region, and source region. Here, The source and drain depend on the transistor's structure and operating conditions, so which one is... It is difficult to determine whether something is a source or a drain. The area that functions as a source or drain is sometimes not called a source or drain. For example, they may be referred to as terminal 1 and terminal 2, respectively. These are sometimes referred to as the first electrode and the second electrode. Alternatively, they may be referred to as the first region and the second region. There are cases where this is the case.

[0037] Next, based on the top view and cross-sectional view shown in Figures 1(A) and (B), the method for creating pixels is shown in Figure 1. I will explain using example 2.

[0038] First, a glass substrate can be used for the light-transmitting substrate 111. The above prevents the diffusion of impurities from the substrate 111, or ensures close contact with each element provided on the substrate 111. The diagram shows a configuration that includes a base film 112 to improve performance. Note that the base film 112 is not required. There is no need to set one up.

[0039] Next, after forming a conductive layer over the entire surface of the substrate 111, the first photolithography process is performed. A resist mask is formed, and unwanted parts are removed by etching to create the first wiring 101A. , a capacitive electrode 101B is formed. At this time, at least the first wiring 101A and the capacitive electrode 1 Etch the end of 01B so that it becomes tapered.

[0040] The first wiring 101A and the capacitive electrode 101B are made of aluminum (Al) or copper (Cu), etc. It is desirable to form it with a low-resistance conductive material, but pure Al has poor heat resistance and is also corrosive. Because of issues such as low cost, it is formed in combination with a heat-resistant conductive material. The materials used are titanium (Ti), tantalum (Ta), tungsten (W), and molybdenum (M). o), an element selected from chromium (Cr), neodymium (Nd), scandium (Sc), or an alloy containing the above-mentioned elements, or an alloy combining the above-mentioned elements, or the above-mentioned It is formed from nitrides composed of the specified elements.

[0041] Furthermore, the wiring and other components that make up the TFT can be formed using inkjet or printing methods. These technologies enable manufacturing at room temperature, under low vacuum conditions, or on large substrates. Because it can be manufactured without using a photomask, the transistor layout can be modified. It can be easily modified. Furthermore, since there is no need to use a resist, the material cost is low. This reduces the number of steps involved. Furthermore, inkjet and printing methods can be used to shape resist masks, etc. It is also possible to form a resist only in the necessary areas using inkjet or printing methods. Furthermore, by exposing and developing the material to create a resist mask, it is possible to form a resist over the entire surface rather than forming a resist over the entire surface. This allows for cost reduction.

[0042] Furthermore, a multi-gradation mask creates a resist mass with multiple (typically two) thickness regions. You may form a loop and then form wiring or other structures.

[0043] Next, an insulating film (hereinafter referred to as gate insulating film 11) is applied to the first wiring 101A and the capacitive electrode 101B. A film (referred to as 3) is deposited over the entire surface. The gate insulating film 113 is deposited using a sputtering method or the like.

[0044] For example, the gate insulating film 113 is formed using a silicon oxide film by sputtering. Of course, the gate insulating film 113 is not limited to such silicon oxide films, but also nitrogen oxides. Other insulating films such as silicon oxide films, silicon nitride films, aluminum oxide films, and tantalum oxide films. These materials may be used to form a single-layer or laminated structure.

[0045] Furthermore, before depositing the oxide semiconductor film, an inverse plasma is generated by introducing argon gas. It is preferable to perform puttering to remove dust adhering to the surface of the gate insulating film 113. Nitrogen, helium, etc. may be used instead of an argon atmosphere. The procedure can also be carried out in an atmosphere with oxygen, N2O, etc. added to the surrounding air. Alternatively, Cl2 in an argon atmosphere can be used. You can also do it in a style that incorporates CF4, etc.

[0046] Next, an oxide semiconductor is placed on the gate insulating film 113, and the surface of the gate insulating film 113 undergoes plasma treatment. After processing, the film is deposited without exposure to the atmosphere. Oxide semiconductors are used as semiconductor layers in transistors. By doing so, compared to silicon-based semiconductor materials such as amorphous silicon, the field effect transfer is improved. The degree can be increased. Examples of oxide semiconductors include zinc oxide (ZnO) and acid Tin oxide (SnO2) can also be used. Furthermore, in addition to ZnO, in addition to ga, etc. It is also possible to do so.

[0047] InMO3(ZnO) is an oxide semiconductor. x Using a thin film denoted as (x>0) Yes, it is possible. Note that M stands for gallium (Ga), iron (Fe), nickel (Ni), and manganese (M). n) represents one or more metallic elements selected from cobalt (Co). For example, In addition to the possibility of M being Ga, other combinations such as Ga and Ni or Ga and Fe, etc., are also possible. Metal elements may be present. Furthermore, in the above oxide semiconductor, gold may be included as M. In addition to the group elements, impurity elements include Fe, Ni, and other transition metal elements, or acids of said transition metals. Some contain oxidized compounds. For example, the In-Ga-Zn-O system as an oxide semiconductor layer. A membrane can be used.

[0048] Oxide semiconductor (InMO3(ZnO) x (x>0) InGa-Zn-O system film Instead, InMO3(ZnO) is formed by replacing M with another metallic element. x (x>0) A membrane can also be used. In addition to the above, other oxide semiconductors include In-Sn-Zn-O and In-Al-Z nO system, Sn-Ga-Zn-O system, Al-Ga-Zn-O system, Sn-Al-Zn-O system , In-Zn-O system, Sn-Zn-O system, Al-Zn-O system, In-O system, Sn-O system, Zn-O based oxide semiconductors can be applied.

[0049] Furthermore, an In-Ga-Zn-O system is used as the oxide semiconductor. Here, In2O3:G A target with a ratio of a2O3:ZnO = 1:1:1 is used. The distance between the substrate and the target is Distance 100mm, pressure 0.6Pa, DC power supply 0.5kW, oxygen (oxygen flow rate ratio 1 The film is deposited in a 00% atmosphere. Note that if a pulsed DC power supply is used, the following will occur during film deposition. This reduces the amount of powdery material (also called particles or dust) and ensures a uniform film thickness distribution. preferable.

[0050] Furthermore, the oxide semiconductor film deposition was performed using the same chamber in which the reverse sputtering was previously carried out. Alternatively, the film may be deposited in a different chamber than the one in which the reverse sputtering was performed earlier.

[0051] Sputtering methods include RF sputtering, which uses a high-frequency power supply for sputtering, and DC sputtering, which uses a DC power supply. There is DC sputtering, and also pulsed DC sputtering, which applies a pulsed bias. Sputtering is mainly used for depositing insulating films, while DC sputtering is mainly used for depositing metal films. It is used in the following cases:

[0052] There are also multi-point sputtering systems that can set up multiple targets made of different materials. The apparatus can deposit multiple layers of different material films in the same chamber, or multiple types of materials in the same chamber. It is also possible to deposit films by simultaneously discharging electrical currents from similar materials.

[0053] Furthermore, a sputtering apparatus that uses the magnetron sputtering method, which has a magnetic mechanism inside the chamber. Alternatively, ECR sputtering uses plasma generated with microwaves instead of glow discharge. There are sputtering machines that use this method.

[0054] Furthermore, as a film deposition method using the sputtering method, the target material and sputtering gas components are deposited during film deposition. Reactive sputtering is a method that uses chemical reactions to form thin films of these compounds, and during film formation... There is also a bias sputtering method that applies voltage to the circuit board.

[0055] Next, the oxide semiconductor layer is dehydrated or dehydrogenated. The heat treatment temperature for step 1 is 400°C or higher and less than 750°C, preferably 425°C or higher. If the temperature is 425°C or higher, the heat treatment time can be 1 hour or less, but if it is below 425°C... If so, the heat treatment time shall be longer than 1 hour. Here, one of the heat treatment apparatuses The substrate is introduced into an electric furnace, and the oxide semiconductor layer is heat-treated under a nitrogen atmosphere. After this process, without exposure to the atmosphere, the re-incorporation of water and hydrogen into the oxide semiconductor layer is prevented, and oxidation occurs. A material semiconductor layer is obtained. In this embodiment, the oxide semiconductor layer is dehydrated or dehydrogenated. Using the same furnace, from a thermal temperature T, the temperature is raised to a sufficient temperature so that no water enters again, specifically the heating temperature Slowly cool under a nitrogen atmosphere until the temperature drops by more than 100°C below degree T. Furthermore, it is not limited to a nitrogen atmosphere. Dehydration or dehydrogenation occurs under a noble gas atmosphere (helium, neon, argon, etc.). To do so.

[0056] Furthermore, the heat treatment device is not limited to electric furnaces, but also includes heat conduction or heat from heat-generating elements such as resistance heating elements. The device may include an apparatus that heats the object to be processed by radiation. For example, GRTA(Gas Rapid Thermal Anneal) equipment, LRTA (Lamp Rapid RTA (Rapid Thermal Angle) for Thermal Annealing devices, etc. A neal device can be used. The LRTA device uses halogen lamps and metal halide lamps. Lamps, xenon arc lamps, carbon arc lamps, high-pressure sodium lamps, high pressure A device that heats an object to be processed by radiation of light (electromagnetic waves) emitted from lamps such as mercury lamps. The GRTA device is a device that performs heat treatment using high-temperature gas. The gas contains A Noble gases such as argon, or nitrogen, which hardly react with the material being treated during heat treatment. An inert gas is used.

[0057] By heat-treating the oxide semiconductor layer at a temperature of 400°C to less than 750°C, the oxide semiconductor layer Dehydration and dehydrogenation are achieved, preventing subsequent re-impregnation with water (H2O).

[0058] Furthermore, in the first heat treatment, nitrogen or noble gas such as helium, neon, or argon is used. It is preferable that it does not contain water, hydrogen, etc. Alternatively, nitrogen introduced into the heat treatment device, Alternatively, the purity of noble gases such as helium, neon, and argon must be 6N (99.9999%) or higher. Preferably 7N (99.99999%) or higher (i.e., impurity concentration of 1 ppm or less, preferably It is preferable to keep the concentration at 0.1 ppm or less.

[0059] Furthermore, depending on the conditions of the first heat treatment, or the material of the oxide semiconductor layer, the oxide semiconductor layer In some cases, crystallization may occur, forming a microcrystalline or polycrystalline film. For example, if the crystallization rate is 90% or higher. Alternatively, it may become an oxide semiconductor film with more than 80% microcrystalline properties. Also, the first heat treatment Depending on the conditions or the material of the oxide semiconductor layer, amorphous oxide semiconductors that do not contain crystalline components may be used. It can also form a conductive film.

[0060] The oxide semiconductor layer becomes oxygen-deficient after the first heat treatment for dehydration or dehydrogenation. , reducing resistance. The oxide semiconductor layer after the first heat treatment is less durable than the oxide semiconductor film immediately after deposition. The carrier concentration also increases, preferably 1 × 10⁻⁶ 18 / cm 3 Having the above carrier concentration This forms an oxide semiconductor layer.

[0061] Next, a second photolithography process is performed to form a resist mask, followed by etching. By removing the unnecessary parts, the first oxide semiconductor layer 103A and the second oxide semiconductor layer are made of oxide semiconductor material. The oxide semiconductor layer 103B is formed. Note that the first oxide semiconductor layer 103A and the second oxide The first heat treatment of the semiconductor layer 103B is performed on the oxide semiconductor before it is processed into an island-shaped oxide semiconductor layer. This can also be done on conductive films. The etching method used in this case is wet etching or dry etching. Lye etching is used. A cross-sectional view at this stage is shown in Figure 2(A).

[0062] Furthermore, after the gate insulating film 113 is formed, the gate insulating film 113 is treated as shown in Figure 2(A). An opening 121 is formed that reaches the capacitance electrode 101B, and the connection between the wiring to be formed later and the capacitance electrode is made You may do so.

[0063] Next, a conductive film made of a metallic material is formed on the oxide semiconductor layer using sputtering or vacuum deposition. The conductive film material may be an element selected from Al, Cr, Ta, Ti, Mo, W, or Examples include alloys composed of the elements mentioned above, or alloys combining the elements mentioned above. Furthermore, when performing heat treatment at 200°C to 600°C, the conductive film must have sufficient heat resistance to withstand this heat treatment. It is preferable to have it. Al alone has problems such as poor heat resistance and susceptibility to corrosion. Therefore, it is formed in combination with a heat-resistant conductive material. Heat-resistant conductive material combined with Al Examples include titanium (Ti), tantalum (Ta), tungsten (W), and molybdenum (Mo). ), elements selected from chromium (Cr), neodymium (Nd), and scandium (Sc), This refers to an alloy containing the above-mentioned elements, or an alloy combining the above-mentioned elements, or the above-mentioned It is formed from nitrides composed of elements.

[0064] Here, a single-layer titanium film structure is used as the conductive film. Alternatively, the conductive film can also be a two-layer structure. Often, a titanium film may be laminated on an aluminum film. Also, a Ti film may be used as a conductive film, and An aluminum (Al-Nd) film containing Nd is layered on top of the Ti film, and then on top of that... A three-layer structure with a Ti film may also be used. The conductive film is a single aluminum film containing silicon. A layered structure is also acceptable.

[0065] Next, a third photolithography process is performed to form a resist mask, followed by etching. Further removal of unnecessary parts results in a second wiring 102A, a third wiring 102B, and a power supply, all made of conductive film. Line 104A and the fourth wiring 104B are formed. The etching method used in this process is wet Tectonic etching or dry etching is used. For example, ammonia hydrogen peroxide (31% by weight) For wet etching using hydrogen oxide solution:28 wt% ammonia solution:water (5:2:2) Furthermore, the conductive film of the Ti film is etched to create the second wiring 102A, the third wiring 102B, and the power supply. Line 104A and the fourth wiring 104B are selectively etched to form the first oxide semiconductor layer 1 03A and the second oxide semiconductor layer 103B can be left intact.

[0066] Furthermore, depending on the etching conditions, the oxide semiconductor in the third photolithography process... The exposed area of ​​the layer may be etched. In that case, the second wiring 102A and the third The first oxide semiconductor layer 103A in the region sandwiched between the wiring 102B is on the first wiring 101A. Compared to the oxide semiconductor layer in the region overlapping with the second wiring 102A and the third wiring 102B, the film The thickness becomes thinner. Also, the second acid in the region sandwiched between the power line 104A and the fourth wiring 104B The ionized semiconductor layer 103B is located on the capacitive electrode 101B, along with the power line 104A and the fourth wiring 104B. The film thickness is thinner compared to the oxide semiconductor layer in the overlapping region.

[0067] Next, the gate insulating film 113, the first oxide semiconductor layer 103A, and the second oxide semiconductor layer 1 03B, second wiring 102A, third wiring 102B, power line 104A, fourth wiring 104 An oxide insulating layer 114 is formed on B. At this stage, the first oxide semiconductor layer 103A and Furthermore, a portion of the second oxide semiconductor layer 103B is in contact with the oxide insulating layer 114. Region of the first oxide semiconductor layer 103A that overlaps with the first wiring 101A across the insulating film 113. , and the region of the second oxide semiconductor layer 103B that overlaps with the capacitive electrode 101B is a channel formation region It becomes a region.

[0068] The oxide insulating layer 114 has a thickness of at least 1 nm, and is oxidized by sputtering or other methods. The material insulating layer can be formed using appropriate methods that prevent the incorporation of impurities such as water and hydrogen. In this embodiment, a silicon oxide film is formed as an oxide insulating layer using a sputtering method. The substrate temperature during film formation should be between room temperature and 300°C; in this embodiment, it is 100°C. The deposition of silicon oxide films by sputtering is performed in a noble gas atmosphere (typically argon). Under ambient air, under an oxygen atmosphere, or under a mixed atmosphere of a noble gas (typically argon) and oxygen It can be done by using a silicon oxide target or silicon target. A silicon target can be used in an oxygen and noble gas atmosphere. A silicon oxide film can be formed by sputtering. This results in a low-resistance oxide semiconductor. The oxide insulating layer formed in contact with the body layer is protected from moisture, hydrogen ions, and OH - Contains impurities such as First, an inorganic insulating film is used to block these from entering from the outside, typically as an oxidation Using silicon film, silicon nitride / oxide film, aluminum oxide film, or aluminum oxide / nitride film, etc. Furthermore, the oxide insulating layer formed by the sputtering method is particularly dense, and impurities do not penetrate the adjacent layer. It can be used as a protective film to suppress diffusion phenomena, even as a single layer. Using a target doped with (P) or boron (B), phosphorus (P) or boron ( You can also add B).

[0069] In this embodiment, the purity is 6N, and the silicon target is a columnar polycrystalline B-doped material (resistivity value 0 Using a pressure of 0.01 Ωcm, the distance between the substrate and the target (TS distance) was set to 89 mm, and pressure Pulse test conducted under a pressure of 0.4 Pa, a DC power supply of 6 kW, and an oxygen atmosphere (oxygen flow rate ratio of 100%). The film will be deposited by DC sputtering. The film thickness will be 300 nm.

[0070] Furthermore, the oxide insulating layer 114 is provided in contact with the region that will become the channel formation region of the oxide semiconductor layer. It is also keratinized and functions as a channel protection layer.

[0071] Next, a second heat treatment (preferably 200°C to 400°C, for example 250°C to 3 The process may be carried out at temperatures below 50°C under an inert gas atmosphere or a nitrogen gas atmosphere. For example, A second heat treatment is performed at 250°C for 1 hour under a nitrogen atmosphere. After the second heat treatment, Parts of the first oxide semiconductor layer 103A and the second oxide semiconductor layer 103B form an oxide insulating layer. It is heated in contact with 114.

[0072] A first oxide semiconductor layer 103A whose resistance has been reduced by a first heat treatment, and a second oxide semiconductor When the body layer 103B is in contact with the oxide insulating layer 114, the oxide The region in contact with the insulating layer 114 becomes oxygen-rich. As a result, the first oxide semiconductor layer 1 From the region where 03A and the oxide insulating layer 114 of the second oxide semiconductor layer 103B are in contact, In the depth direction of the first oxide semiconductor layer 103A and the second oxide semiconductor layer 103B, Convert to Type I (increase resistance).

[0073] Next, the oxide insulating layer 114 is subjected to a fourth photolithography process to create the opening 122. Form it. A cross-sectional view at this stage is shown in Figure 2(B).

[0074] Next, a light-transmitting conductive film is formed for connection to the fourth wiring 104B. Materials for conductive films having this property include indium oxide (In2O3) and indium oxide. SnO2 alloys (In2O3-SnO2, abbreviated as ITO), etc., are processed using methods such as sputtering and vacuum deposition. The film is formed using [a specific material]. As another material for a light-transmitting conductive film, nitrogen-containing Al-Zn [another specific material] is used. -O-based films, i.e., Al-Zn-ON-based films, Zn-O-based films containing nitrogen, and nitrogen-containing films A Sn-Zn-O system film may also be used. Note that the zinc composition ratio of the Al-Zn-ON system film is also important. The atomic percentage (Atomic%) should be 47 atomic% or less, and should be greater than the composition ratio (Atomic%) of aluminum in the film. The proportion of aluminum in the film (atomic %) is greater than the proportion of nitrogen in the film (atomic %). Etching of such materials is performed using hydrochloric acid-based solutions. However, especially with ITO Since etching tends to generate residue, indium oxide is used to improve etching processability. Zinc oxide alloy (In2O3-ZnO) may also be used.

[0075] The composition ratio of the light-transmitting conductive film is expressed in atomic percent, and the electron beam microanalyzer... (EPMA:Electron Probe X-ray MicroAnalyzer The evaluation shall be conducted by analysis using ).

[0076] Next, a fifth photolithography step is performed to form a resist mask, followed by etching. Further removal of unnecessary parts forms one electrode of the light-emitting element. The light-emitting element consists of a pair of electrodes (positive The device has a configuration comprising a light-emitting layer between the electrode and the cathode, with the elements constituting the light-emitting layer being stacked on the electrodes. It is formed in this way. Therefore, one electrode of the light-emitting element is called the light-emitting element 105.

[0077] Next, the first wiring 101A, the second wiring 102A, the third wiring 102B, and the fourth wiring 1 04B, first oxide semiconductor layer 103A, second oxide semiconductor layer 103B, power line 104 A and a partition wall 106 are provided on the capacitive electrode 101B to separate the light-emitting elements for each pixel. A light-emitting element 105 connected to the fourth wiring 104B is provided inside the partition wall 106. This will result in a cross-sectional view at this stage, as shown in Figure 2(C).

[0078] Thus, the device has a first thin-film transistor 107A and a second thin-film transistor 107B. Pixels can be created. Then, these can be arranged in a matrix corresponding to individual pixels. An active-matrix type light-emitting display device is fabricated by arranging the elements to form the pixel section. It is possible.

[0079] The advantages of the configuration of this embodiment, as explained in Figures 1 and 2, are illustrated in Figures 3(A) and (B). I will explain in detail.

[0080] Figures 3(A) and 3(B) are enlarged views of the vicinity of the oxide semiconductor layer in the top view of Figure 1(A). Also, the width of the first oxide semiconductor layer 103A in Figure 3(A) (W1 in Figure 3(A)) A larger version of the diagram shows the width of the first oxide semiconductor layer 103A in Figure 3(B) (in Figure 3(B), This corresponds to the diagram labeled W2).

[0081] In this embodiment, the top view of the pixels in Figure 1(A) is as shown in Figures 3(A) and (B). Without branching the wiring from the first wiring 101A, the first wiring 101A An oxide semiconductor layer 103A is provided. The second wiring 102A and the third wiring in the oxide semiconductor layer The channel region formed between wiring 102B and the superimposed region on the first wiring 101A The first oxide semiconductor layer 103A is formed when light is irradiated into the channel region. This can cause variations in TFT characteristics, so the first wiring 101A was branched off. The need to reliably block light through wiring was a factor that reduced the aperture ratio of the pixels. An oxide semiconductor layer is provided so as to be superimposed on the first wiring 101A, which is the configuration of the embodiment. By not forming wiring branched from the first wiring 101A, the aperture ratio can be improved. Cut.

[0082] Furthermore, a translucent oxide semiconductor layer is used as the semiconductor layer of the thin-film transistor. As a result, the oxide semiconductor layer is shifted from the region where it overlaps with the first wiring 101A to the position in the design. Even when formed in a specific region and superimposed with the light-emitting element 105, the aperture ratio is reduced. It is possible to display it without any issues.

[0083] By forming an oxide semiconductor layer with a pattern larger than a predetermined size, multiple patterns can be formed from the design position. Even if an oxide semiconductor layer is formed in a slightly misaligned location, this can lead to malfunctions and a decrease in aperture ratio. It can display clearly without any problems. Therefore, the active matrix of the light-emitting display device This makes it easier to manufacture the substrates, which can lead to an improvement in yield.

[0084] Next, by using a thin-film transistor with an oxide semiconductor layer, the retention capacitance is reduced. An example of a specific top view for this process is shown below.

[0085] In thin-film transistors having oxide semiconductors, the gate is set to a non-conductive state. The current flowing through the transistor when a voltage is applied (hereinafter referred to as leakage current) is 0.1 pA. In contrast to the following, thin-film transistors with amorphous silicon have a current of several hundred nA. This is the extent of the reduction in retention capacitance in thin-film transistors with oxide semiconductors. This can be achieved in pixels where a thin-film transistor having an oxide semiconductor is provided. Compared to pixels equipped with thin-film transistors having amorphous silicon, the range of each element is This allows for greater flexibility in the selection process.

[0086] Thin-film transistors with an oxide semiconductor layer have very low leakage current, therefore, the retained capacitance is low. It is also possible to omit this. Specifically, a top view and a cross-section when the holding capacity is omitted. The diagram is shown in Figures 12(A) and (B). The top view of the pixels shown in Figure 12(A) is explained above. This corresponds to the top view in Figure 1(A) with the capacitance lines omitted. As can be seen from the top view and the cross-sectional view shown in Figure 12(B), a thin film having an oxide semiconductor layer. By using transistors, the arrangement of the second thin-film transistors determines the third wiring 10 This allows for shorter routing of components such as 2B, thereby improving the aperture ratio.

[0087] As described above, by adopting the configuration shown in this embodiment, a thin oxide semiconductor can be used. When fabricating pixels equipped with film transistors, it is possible to improve the aperture ratio. Therefore, This allows for the creation of a light-emitting display device with a high-definition display section.

[0088] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0089] (Embodiment 2) An example of configuring pixels in a display device with a TFT configuration different from the embodiment described above is described below.

[0090] Figure 4(A) shows a top view of the pixels, which differs from the configuration of Embodiment 1. The TFT structure shown is a bottom-gate type structure, and the channel is viewed from the gate wiring. On the opposite side of the oxide semiconductor layer which forms the drain region, the source and drain electrodes of the TFT are arranged. This shows a so-called inverse staggered configuration that has a layer of wires.

[0091] Pixel 400 shown in Figure 4(A) is the first wiring 401A which functions as a scan line, and the signal line The second wiring 402A, the first oxide semiconductor layer 403A, and the second oxide semiconductor layer function together. It has 403B, a power line 404A, a capacitive electrode 401B, and a light-emitting element 405. Also, the first Third wiring 40 for electrically connecting the oxide semiconductor layer 403A and the capacitive electrode 401B It has 2B, and the first thin-film transistor 407A is formed. Also, the second oxide semiconductor It has a fourth wiring 404B for electrically connecting layer 403B and light-emitting element 405, Two thin-film transistors 407B are formed. Also, the first wiring 401A and the second wiring 40 2A, third wiring 402B, fourth wiring 404B, first oxide semiconductor layer 403A, second On the oxide semiconductor layer 403B, the power line 404A, and the capacitive electrode 401B, a light-emitting element is provided. A partition wall 406 is provided to separate each pixel. A fourth wiring 4 is located inside the partition wall 406. A light-emitting element 405 will be provided to be connected to 04B.

[0092] The first wiring 401A is also a wiring that functions as the gate of the first thin-film transistor 407A. Yes. Capacitive electrode 401B is one of the gate and holding capacitances of the second thin-film transistor 407B. It is also a wiring that functions as an electrode. The second wiring 402A is the first thin film transistor. This wiring also functions as either the source or drain electrode of the ZISTA 407A. Wiring 402B in section 3 is either the source or drain electrode of the first thin-film transistor 407A. It is also a wiring that functions as the other side. Power line 404A is connected to the second thin-film transistor 407 The electrode that functions as either the source electrode or the drain electrode of B, and the other electrode of the holding capacity It is also a line. The fourth wire 404B is the source electrode of the second thin-film transistor 407B. This is also the wiring that functions as the other side of the drain electrode.

[0093] The first wiring 401A and the capacitive electrode 401B are provided from the same layer, and the second wiring 402 A, the third wiring 402B, the power line 404A, and the fourth wiring 404B are provided from the same layer. Furthermore, the power line 404A and the capacitive electrode 401B are provided in a partially overlapping manner, and the second This forms the retention capacitance of the thin-film transistor 407B. The first oxide semiconductor layer 403A of 07A has a gate insulating film on the first wiring 401A. It is provided via (not shown), and the first oxide semiconductor layer 403A is connected to the first wiring 40 It extends beyond the area where 1A and partition wall 406 are provided.

[0094] Figure 4(B) also shows the cross-sections between the dashed lines A-A', B-B', and C-C' in Figure 4(A). The surface structure is shown. In the cross-sectional structure shown in Figure 4(B), the substrate 411 has a base film 4 A first wiring 401A, which is a gate, and a capacitive electrode 401B are provided via 12. A gate insulating film 413 is provided so as to cover the first wiring 401A and the capacitive electrode 401B. On the gate insulating film 413, there is a first oxide semiconductor layer 403A and a second oxide semiconductor layer A conductive layer 403B is provided. A second wiring 4 is provided on the first oxide semiconductor layer 403A. On the third wiring 402B and the second oxide semiconductor layer 403B, there is a power line 404A. A fourth wiring 404B is provided. Also, the first oxide semiconductor layer 403A and the second acid The ionized semiconductor layer 403B, the second wiring 402A, the third wiring 402B, the power line 404A, and On the fourth wiring 404B, there is an oxide insulating layer 414 which functions as a passivation film. It is provided. First wiring 401A, second wiring 402A, third wiring 402B, fourth Wiring 404B, first oxide semiconductor layer 403A, second oxide semiconductor layer 403B, power supply A partition wall 406 is provided on the oxide insulating layer 414 on the wire 404A and the capacitive electrode 401B. Furthermore, an opening is formed in the oxide insulating layer 414 on the fourth wiring 404B. At the opening, the electrodes of the light-emitting element 405 are connected to the fourth wiring 404B. In the dashed line B-B', the third wiring 402B and the capacitive electrode 401B are connected by a gate insulating film. It is connected through an opening formed in 413.

[0095] Note that the pixels shown in Figures 4(A) and (B) are the same as those described in Figures 1(A) and (B) of Embodiment 1. Similarly, in Figure 7, multiple pixels 701 arranged in a matrix on the substrate 700. The explanation regarding Figure 7 is the same as in Embodiment 1.

[0096] Furthermore, the cross-sectional view shown in Figure 4(B) is the same as the cross-sectional view shown in Figure 1(B), and the pixel fabrication process The method is the same as described in Figure 2 of Embodiment 1.

[0097] The advantages of the configuration of this embodiment, as explained in Figures 4(A) and 4(B), are shown in Figures 5(A) and 4(B). ) will be used to provide a detailed explanation.

[0098] Figures 5(A) and 5(B) are enlarged views of the vicinity of the oxide semiconductor layer in the top view of Figure 4(A). Also, the width of the first oxide semiconductor layer 403A in Figure 5(A) (W1 in Figure 5(A)) A larger version of the diagram shows the width of the first oxide semiconductor layer 403A in Figure 5(B) (in Figure 5(B), This corresponds to the diagram labeled W2).

[0099] In this embodiment, the top view of the pixels in Figure 4(A) is as shown in Figures 5(A) and (B). Furthermore, without branching the wiring from the first wiring 401A, the first wiring 401A is connected to the first An oxide semiconductor layer 403A is provided. The second wiring 402A and the third wiring in the oxide semiconductor layer The channel region formed between wiring 402B and the superimposed region on the first wiring 401A In addition, in this embodiment, the first oxide semiconductor layer 403A is the first The second wiring 402A and the third wiring 402B extend over the gate insulating film on wiring 401A. This will come into contact with it.

[0100] The first oxide semiconductor layer 403A exhibits TFT characteristics when light is irradiated into the channel region. Because light may occur, ensure that the wiring branched from the first wiring 401A provides reliable light shielding. This process was necessary and also contributed to lowering the pixel aperture ratio. This is the configuration of this embodiment. An oxide semiconductor layer is provided so as to be superimposed on the first wiring 401A, and from the first wiring 401A A configuration that does not form branched wiring, and extending on the gate insulating film on the first wiring 401A The second wiring 402A and the third wiring 402B are in contact with the first oxide semiconductor layer 403A. This allows for an improvement in the aperture ratio.

[0101] Furthermore, a translucent oxide semiconductor layer is used as the semiconductor layer of the thin-film transistor. As a result, the oxide semiconductor layer is shifted from the region where it overlaps with the first wiring 401A to the position in the design. Even when formed in a region and superimposed with the light-emitting element 405, the aperture ratio is reduced. It is possible to display it without any issues.

[0102] Furthermore, the second wiring 402A and the third wiring extending along the first wiring 401A shown in Figure 4(A) Line 402B only needs to be superimposed on the first wiring 401A. Also, the second wiring 402A and the third wiring 402B may be routed in a meandering manner. Alternatively, the wiring may be arranged in a straight line.

[0103] By forming an oxide semiconductor layer with a pattern larger than the predetermined size, the design position can be slightly different. Even if an oxide semiconductor layer is formed in a misaligned location, malfunction and a decrease in aperture ratio will occur. It can display well without any problems. Therefore, the active matrix of the light-emitting display device This makes it easier to manufacture risk substrates, which can lead to improved yield.

[0104] As described above, by adopting the configuration shown in this embodiment, a thin oxide semiconductor can be used. When fabricating pixels equipped with film transistors, it is possible to improve the aperture ratio. Therefore, This allows for the creation of a light-emitting display device with a high-definition display section.

[0105] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0106] (Embodiment 3) An example of configuring pixels in a display device with a TFT configuration different from the embodiment described above is described below.

[0107] Figures 6(A) and (B) show a top view and cross-sectional view of the pixels, which differ from the configuration of Embodiment 2. The structure of the top view shown in Figure 6(A) is the same as that of Figure 4(A), and therefore will not be explained here. Omitted. Also, the structure of the cross-sectional view shown in Figure 6(B) is different from the structure of the cross-sectional view shown in Figure 4(B). One point to note is that an interlayer insulating layer 601A is provided between the first wiring 401A and the second wiring 402A. The components are formed, and an interlayer insulating layer 601 between the first wiring 401A and the third wiring 402B. The key feature is the configuration that includes B.

[0108] The second wiring 402A and the third wiring 402B are provided extending from the first wiring 401A. In some cases, depending on the thickness of the gate insulating film 413, the first wiring 401A and the second wiring 402A , between the first wiring 401A and the third wiring 402B, and between the first wiring 401A and power line 4 Parasitic capacity will be generated between 04A. Therefore, as shown in Figure 6(B), interlayer isolation By providing the edge layer 601A and the interlayer insulating layer 601B, parasitic capacitance is reduced, preventing malfunctions and other defects. It can be reduced.

[0109] As described above, by adopting the configuration shown in this embodiment, a thin oxide semiconductor can be used. When fabricating pixels equipped with film transistors, it is possible to improve the aperture ratio. In this embodiment, in addition to the configuration of the second embodiment described above, it is possible to reduce the parasitic capacity. Therefore, a light-emitting display device having a high-definition display unit and capable of reducing malfunctions is required. It is possible.

[0110] (Embodiment 4) In this embodiment, the configuration of the light-emitting element, which is a display element, will be described.

[0111] Figure 9 shows one form of the cross-sectional structure of a light-emitting element connected to a thin-film transistor. The light-emitting element consists of a first electrode 911, an EL layer 913 having a light-emitting layer, and a second electrode 914. These are arranged in a stack in order. Either the first electrode 911 or the second electrode 914 is the anode. One side functions as the anode, and the other as the cathode. The light-emitting element receives holes injected from the anode and the cathode The electrons injected into the EL layer recombine in the light-emitting layer and emit light. The pole 911 is connected to the thin-film transistor 107B formed on the substrate 111. Covering one electrode that will be the source or drain of the film transistor 107B and the first electrode 911. A partition wall 106 is provided in such a manner. Also, at the opening of the partition wall 106 on the first electrode 911, E An L layer 913 is provided, and a second electrode 914 is provided so as to cover the EL layer 913 and the partition wall 106. In this embodiment, the thin-film transistor shown in Embodiment 1 was used. Alternatively, thin-film transistors as shown in other embodiments can be used.

[0112] The first electrode 911 or the second electrode 914 is made of a metal, alloy, or electrically conductive compound. It is formed by doing so.

[0113] For example, the first electrode 911 or the second electrode 914 has a large work function (work function is 4. Metals, alloys, and electrically conductive compounds (above 0 eV) can be used. Typically, oxidation Indium tin oxide (ITO), silicon, or acid Indium oxide-tin oxide and indium oxide-zinc oxide (IZO:In) containing silicon dioxide. zinc oxide containing zinc oxide, tungsten oxide, and zinc oxide There is a transparent conductive metal oxide layer, such as zinc (IWZO).

[0114] Furthermore, the first electrode 911 or the second electrode 914 has a small work function (typically, work (Functions of 3.8 eV or less) Metals, alloys, electrically conductive compounds, etc. can be used. In general, elements belonging to Group 1 or Group 2 of the periodic table, such as lithium and cesium. Alkali metals, and alkaline earth metals such as magnesium, calcium, and strontium. Metals, and alloys containing these (alloys of aluminum, magnesium and silver, alloys of aluminum and lithium), rare earth metals such as europium and ytterbium, and alloys containing these exist.

[0115] Alkali metals, alkaline earth metals, and alloys containing these are formed using, for example, vacuum evaporation methods, sputtering methods, etc. It is also possible to form them by ejecting silver paste or the like by an inkjet method and firing. Further, the first electrode 911 and the second electrode 914 are not limited

[0116] to being single-layer, and can also be formed by lamination. In order to extract the light emitted by the EL layer to the outside, either one or both of the first electrode 911 and the second electrode 91 4 are formed so as to transmit the light emitted from the EL layer. When only the first electrode 911 is a light-transmitting electrode, the light passes through the first electrode 911 as shown by the arrow direction 900, and is extracted from the substrate 111 side with a luminance corresponding to the video signal input from the signal line. Also, when only the second electrode 914 is a light-transmitting electrode, the light passes through the second electrode 914 and is extracted from the sealing substrate 916 side with a luminance corresponding to

[0117] the video signal input from the signal line. When both the first electrode 911 and the second electrode 914 are light-transmitting electrodes, the light passes through the first electrode 911 and the second electrode 914, and is extracted from both the substrate 111 side and theA thin metal layer such as silver or aluminum, and a transparent conductive metal oxide layer. It can also be arranged in a layered structure.

[0118] Either the first electrode 911 or the second electrode 914, which functions as the anode, has a large work function. (Work function of 4.0 eV or higher) It is preferable to use metals, alloys, electrically conductive compounds, etc. Furthermore, the other of the first electrode 911 or the second electrode 914, which functions as a cathode, has a work function of It is preferable to use metals, alloys, or electrically conductive compounds with a small work function (3.8 eV or less). Typical examples include alkali metals, alkaline earth metals, and alloys and compounds containing them. They can also be formed using transition metals, including rare earth metals.

[0119] The EL layer 913 has a light-emitting layer. In addition to the light-emitting layer, the EL layer 913 also has hole injection The structure may include layers, a hole transport layer, an electron transport layer, and an electron injection layer. The hole transport layer is connected to the anode and light emission. It is placed between the layers. Additionally, the hole injection layer is located between the anode and the light-emitting layer, or between the anode and the hole transport layer. It is provided between the two. On the other hand, the electron transport layer is provided between the cathode and the light-emitting layer. Electron injection The layer is placed between the cathode and the light-emitting layer, or between the cathode and the electron transport layer. It is not necessary to provide all layers, including the hole transport layer, electron transport layer, and electron injection layer; they can be provided as needed. You can select and install them according to their functions and other requirements.

[0120] The light-emitting layer contains a light-emitting substance. Examples of light-emitting substances include fluorescent substances that emit fluorescence. Compounds or phosphorescent compounds that emit phosphorescence can be used.

[0121] Furthermore, the light-emitting layer can be formed by dispersing a light-emitting substance in a host material. When dispersed in a light-emitting material to form a light-emitting layer, the light-emitting substances cause a quenching reaction between them, resulting in concentration quenching. It can suppress phenomena such as crystallization.

[0122] When the luminescent substance is a fluorescent compound, the host material is more singlet excited than the fluorescent compound. Using materials with a large energy (the energy difference between the ground state and the singlet excited state) It is preferable. Furthermore, in the case of phosphorescent compounds, the host material is more triplet excited than the phosphorescent compound. Using materials with a large energy (the energy difference between the ground state and the triplet excited state) preferable.

[0123] Furthermore, the luminescent substances dispersed in the host material include the phosphorescent compounds and fluorescent compounds mentioned above. A blend can be used.

[0124] Furthermore, two or more types of host materials and a light-emitting substance may be used as the light-emitting layer, or two types A luminescent substance of a certain class or higher and a host material may be used. In addition, two or more types of host materials and Two or more luminescent materials may be used.

[0125] Furthermore, the hole injection layer includes a layer containing a material with high hole transport properties and a material that exhibits electron-accepting properties. It is possible. A layer containing a material with high hole transport properties and a material that exhibits electron acceptance can be a carrier. It has high density and excellent hole injection properties. Furthermore, it exhibits electron-accepting properties in materials with high hole transport capabilities. By using a layer containing such a material as a hole injection layer in contact with the electrode that functions as the anode, Therefore, regardless of the magnitude of the work function of the electrode material that functions as the anode, various metals, alloys, and electrical Conductive compounds and mixtures thereof can be used.

[0126] The light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer can be formed by vapor deposition, coating, or the like. It can be formed by.

[0127] Also, a passivation layer 915 may be formed on the second electrode 914 and the partition wall 106 by sputtering method or CVD method. By providing the passivation layer 915, deterioration of the light-emitting element due to intrusion of moisture and oxygen from the outside can be reduced. Furthermore nitrogen may be enclosed in the space between the passivation layer 915 and the sealing substrate 916, and a desiccant may be arranged. Alternatively, the space between the passivation layer 915 and the sealing substrate 916 may be filled with an organic resin having light transmittance and high water absorption. It may be filled with an organic resin having light transmittance and high water absorption.

[0128] When the light-emitting element exhibits white light emission, full-color display can be performed by providing a color filter, a color conversion layer, or the like on the substrate 11 1 or the sealing substrate 916.

[0129] Also, in order to enhance the contrast, a polarizing plate or a circular polarizing plate may be provided on the substrate 111 or the sealing substrate 916.

[0130] In the pixel of the present embodiment as well, by combining the configurations of the above-described embodiments, when fabricating a pixel including a thin film transistor using an oxide semiconductor, the aperture ratio can be improved by taking measures.

[0131] The present embodiment can be implemented by appropriately combining with the configurations described in other embodiments. It is possible.

[0132] (Embodiment 5) In the present embodiment, a circuit configuration of a pixel applicable to a light-emitting display device will be described.

[0133] Figure 8 shows an example of a pixel configuration that can be applied to a light-emitting display device. Pixel 800 is the first Thin-film transistor 801, second thin-film transistor 802, capacitive element 803, light-emitting element It has 804. The gate of the first thin-film transistor 801 is connected to the first wiring 805 and electrical They are connected. The first terminal of the first thin-film transistor 801 is electrically connected to the second wiring 806. The second terminal of the first thin-film transistor 801 is connected to the first electrode of the capacitive element 803. The second thin-film transistor 802 is electrically connected to the gate of the capacitive element 803. The electrode is electrically connected to the power line 807. First terminal of the second thin-film transistor 802. It is electrically connected to the power line 807. The second terminal of the second thin-film transistor 802 is It is electrically connected to one electrode of the light-emitting element 804.

[0134] Regarding the first wiring 805, the functions of the first wiring 101A described in Embodiment 1 above are as follows: The same applies to the second wiring 806. The function is the same as that of 2A. Regarding the power line 807, it is the same as the power line described in Embodiment 1 above. It is equivalent to the function of 104A. The configuration of the light-emitting element 804 is described in Embodiment 4 above. This is equivalent to the configuration of the light-emitting element described.

[0135] In the pixels of this embodiment as well, by combining the configuration of the above embodiment, acid When fabricating pixels equipped with thin-film transistors using semiconductor materials, the aperture ratio is improved. It is possible.

[0136] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0137] (Embodiment 6) In this embodiment, the electronic device equipped with the light-emitting display device described in the above embodiment Let me explain with an example.

[0138] Figure 10(A) shows a portable gaming machine, consisting of a casing 9630, a display unit 9631, and a speaker 9633. It may have, for example, an operation key 9635, a connection terminal 9636, a recording medium reading unit 9672, etc. The portable gaming machine shown in Figure 10(A) has a program or data recorded on the recording medium. Features include the ability to read data and display it on the display unit, and the ability to share information wirelessly with other portable gaming machines. It can have the following functions, etc. Note that the portable gaming machine shown in Figure 10(A) has The functions are not limited to these, and it can have a variety of functions.

[0139] Figure 10(B) shows a digital camera, consisting of a housing 9630, a display unit 9631, and a speaker 963 3. Operation key 9635, connection terminal 9636, shutter button 9676, image receiving unit 9677 It can have, etc. The digital camera with television receiving function shown in Figure 10(B) is Features for taking still images, recording videos, and automatically or manually correcting captured images. Functions, functions to acquire various information from the antenna, captured images, or information acquired from the antenna It has a function to save the information it has collected, and to display the captured image or information acquired from the antenna on the display unit. It can have functions such as the ability to receive television signals. The functions of a camera are not limited to these, and it can have a variety of functions.

[0140] Figure 10(C) shows a television receiver, consisting of a housing 9630, a display unit 9631, and a speaker 9633. It may have an operation key 9635, a connection terminal 9636, etc., as shown in Figure 10(C). A television receiver has the function of processing television signals and converting them into image signals, and processing the image signals. It has functions such as converting signals to those suitable for display, and converting the frame frequency of image signals. It is possible to do so. However, the functions of the television receiver shown in Figure 10(C) are not limited to this. Furthermore, it can have a variety of functions.

[0141] Figure 11(A) shows a computer, consisting of a casing 9630, a display unit 9631, and a speaker 9633. Operation key 9635, connection terminal 9636, external connection port 9680, pointing device It can have chairs 9681, etc. The computer shown in Figure 11(A) can provide various information Functions to display (still images, videos, text images, etc.) on the display unit, various software (P Functions that control processing by program, communication functions such as wireless or wired communication, communication devices Functions that connect to various computer networks using their capabilities, and functions that connect to various data It can have functions for transmitting or receiving data, etc. Note that the code shown in Figure 11(A) The functions of a computer are not limited to these; it can have a variety of functions.

[0142] Next, Figure 11(B) shows a mobile phone, consisting of a casing 9630, a display unit 9631, and a speaker 963 3. It may have operation keys 9635, a microphone 9638, etc. Figure 11(B) The mobile phone shown has the function of displaying various information (still images, videos, text images, etc.). Functions to display a calendar, date, or time on the display unit, and to operate the information displayed on the display unit. This includes editing functions, functions to control processing by various software (programs), etc. It may have these functions. However, the functions of the mobile phone shown in Figure 11(B) are not limited to these. It can have various functions.

[0143] Next, Figure 11(C) shows an electronic paper (also called an e-book), with a casing 9630 and a front It may have an indicator 9631, an operation key 9635, etc. The electronic page shown in Figure 11(C) The page has functions to display various information (still images, videos, text images, etc.), and a calendar. A function to display the date or time on the display unit, and a function to operate or edit the information displayed on the display unit. It has functions, such as the ability to control processing through various software (programs). This is possible. However, the functions of the electronic paper shown in Figure 11(C) are not limited to this. It can have a variety of functions.

[0144] The electronic device described in this embodiment has multiple pixels constituting the display unit, and the aperture ratio Improvement can be achieved.

[0145] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case. [Explanation of Symbols]

[0146] 100 pixels 103 Oxide semiconductor layer 105 Light-emitting element 106 Bulkhead 111 circuit board 112 Undercoat 113 Gate insulating film 114 Oxide insulating layer 121 Opening 122 Opening 400 pixels 405 Light-emitting element 406 Bulkhead 411 circuit board 412 Undercoat 413 Gate insulating film 414 Oxide insulating layer 700 circuit boards 701 pixels 702 pixel section 703 Scan line drive circuit 704 Signal Line Drive Circuit 705 Power supply circuit 800 pixels 801 Thin-film transistor 802 Thin-Film Transistor 803 Capacitive element 804 Light-emitting element 805 Wiring 806 Wiring 807 Power line 900 Arrow direction 911 Electrode 912 Bulkhead 913 EL layer 914 Electrode 915 Passivation Layer 916 Sealing substrate 101A Wiring 101B Capacitive electrode 102A Wiring 102B Wiring 103A Oxide semiconductor layer 103B Oxide semiconductor layer 104A power line 104B Wiring 107A Thin-Film Transistor 107B Thin-Film Transistor 401A Wiring 401B Capacitive electrode 402A Wiring 402B Wiring 403A Oxide Semiconductor Layer 403B Oxide Semiconductor Layer 404A power line 404B wiring 407A Thin-Film Transistor 407B Thin-Film Transistor 601A Interlayer Insulation 601B Interlayer Insulation 9630 cabinet 9631 Display section 9633 Speaker 9635 Operation Keys 9636 Connection terminal 9638 Microphone 9672 Recording medium reading unit 9676 Shutter button 9677 Image receiving unit 9680 External connection port 9681 Pointing device

Claims

[Claim 1] It has multiple pixels having transistors and light-emitting elements, One of the plurality of pixels is electrically connected to a first wiring that functions as a scan line, The transistor has an oxide semiconductor layer provided on the first wiring via a gate insulating film, In a plan view, the oxide semiconductor layer extends beyond the region where the first wiring is provided. A light-emitting device comprising a light-emitting element having a region that overlaps with the oxide semiconductor layer in a plan view.

Images