Display device

Abstract

To simplify a manufacturing process of a thin film transistor that is mounted on an EL display device.SOLUTION: A thin film transistor is manufactured as follows: a first conductive film, an insulating film, a semiconductor film, an impurity semiconductor film, and a second conductive film are stacked; a first resist mask is formed thereover; a thin-film stack body is formed by performing a first etching; a gate electrode layer is formed by performing a second etching including side etching to the thin-film stack body; and then a source electrode and a drain electrode layer and the like are formed using a second resist mask. By using this thin film transistor, an EL display device is manufactured.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an EL display device having a thin film transistor. [Background technology]

[0002] In recent years, a thin film with a thickness of several nm to several hundred nm has been formed on a substrate having an insulating surface such as a glass substrate. Thin-film transistors, which are made of semiconductor thin films of about The data includes electronic devices such as ICs (Integrated Circuits) and electro-optical devices. Thin film transistors are widely used in electronic devices, particularly in liquid crystal displays or electroluminescent (EL) displays. The screen of image display devices, such as photoluminescence (PEL) displays, Development of this element as a switching element is being rushed.

[0003] In an active matrix EL display device, the light emitting element provided in the selected pixel A voltage is applied between one electrode and the other electrode that sandwiches the EL layer together with the first electrode. This causes a current to flow through the EL layer, causing the light-emitting layer to emit light. This light emission is observed as a display pattern. In this case, the active matrix type EL display device is a By driving the pixels arranged in a grid with switching elements, a display panel is formed on the screen. This refers to an EL display device that employs a method in which turns are formed.

[0004] The applications of active matrix EL display devices are expanding, with screen sizes becoming larger and There is a growing demand for higher resolution and higher aperture ratio. High reliability is required for the equipment, and high productivity and reduced production costs are required for the production method. One of the methods to increase productivity and reduce production costs is to simplify the process. do.

[0005] In active matrix EL displays, thin-film transistors are mainly used as switching elements. In the manufacture of thin-film transistors, photolithography is used. Reducing the number of photomasks is important for simplifying the process. When one mask is added, the processes such as resist coating, pre-baking, exposure, development, and post-baking are required. The process includes the formation of a coating film, the etching process, and the resist removal process. This requires cleaning and drying processes, and therefore requires an additional photomask to be used in the manufacturing process. Therefore, the number of steps increases significantly by simply adding a photomask. Many technologies have been developed to reduce this.

[0006] A thin-film transistor is a top-gate transistor in which the channel forming region is provided below the gate electrode. The two types are the top-gate type, in which the channel formation region is provided above the gate electrode, and the bottom-gate type, in which the channel formation region is provided above the gate electrode. The number of photomasks used in the manufacturing process of a bottom-gate type thin film transistor is the number of photomasks used in the manufacturing process of a top-gate thin-film transistor. It is known that the number of photons emitted by a bottom-gate thin-film transistor is less than that of a conventional thin-film transistor. Generally, they are made using a mask.

[0007] Conventional techniques for reducing the number of photomasks include backside exposure, resist reflow, or Many of these involve complex techniques such as the lift-off method, which requires special equipment. The use of such complex technology can lead to various problems, resulting in low yields. In addition, the electrical characteristics of the thin-film transistors had to be sacrificed. Often there isn't.

[0008] A typical method for reducing the number of photomasks in the manufacturing process of thin film transistors. As a step, a multi-tone mask (also called a half-tone mask or gray-tone mask) The technology using multi-tone masks is widely known. For example, Patent Document 1 can be mentioned. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2003-179069 A Summary of the Invention [Problem to be solved by the invention]

[0010] However, when a bottom-gate type thin film transistor is manufactured using the above-mentioned multi-tone mask, Even if the photomask is used in a single step, at least two photomasks are required. It is difficult to reduce the number of these. One of them is used for patterning the gate electrode layer. It is used.

[0011] Here, one aspect of the present invention is to provide a new photomask for patterning a gate electrode layer. The objective of this study is to provide a new method for fabricating thin-film transistors without using any In other words, it does not require complicated technology and can be created with just one photomask. A method for fabricating a thin film transistor is disclosed.

[0012] This allows the number of photomasks used in the manufacture of thin-film transistors to be reduced compared to conventional methods. It is also possible to reduce

[0013] In addition, the thin film transistor according to one embodiment of the present invention is used in particular in a pixel of an EL display device. One embodiment of the present invention is a method for manufacturing an EL display device without using complicated techniques. The objective of the present invention is to reduce the number of photomasks used in the photolithography method compared to the conventional method. Another object of one embodiment of the present invention is to simplify the manufacturing process of an EL display device. [Means for solving the problem]

[0014] In a method for manufacturing a thin film transistor according to one embodiment of the present invention, a first conductive film and A thin film stack in which an insulating film, a semiconductor film, an impurity semiconductor film, and a second conductive film are stacked in this order on a conductive film. and forming a layer body, and exposing the first conductive film by a first etching process, A pattern of the thin film laminate is also formed, and the pattern of the first conductive film is formed by a second etching. Here, the second etching is performed under conditions in which the first conductive film is side-etched. This is done by:

[0015] Here, the first etching may be dry etching or wet etching. However, it is preferable to use a highly anisotropic etching method (physical etching). By using a highly anisotropic etching method for the etching of the pattern, the processing accuracy of the pattern is improved. In addition, when the first etching is performed by dry etching, However, the first etching is preferably performed by wet etching. In this case, the first etching is performed in a plurality of steps. It is preferable to use a dry etch.

[0016] The second etching may be dry etching or wet etching. However, it can be done by etching methods dominated by isotropic etching (chemical etching). It is preferable that the second etching is an etching method in which isotropic etching is dominant (chemical etching). By using the etching gas, the first conductive film can be side-etched. The second etching is preferably wet etching.

[0017] Here, the second etching is performed under conditions that involve side etching of the first conductive film. Therefore, the first conductive film is recessed inward from the patterned thin film stack. After the second etching, the side surface of the first conductive film is larger than the side surface of the patterned thin film stack. Furthermore, the side surface of the patterned first conductive film and the patterned The distances between the sides of the thin film stack are approximately equal.

[0018] The pattern of the first conductive film is, for example, a gate electrode, a gate wiring, and a capacitance electrode. This refers to the top surface layout of the metal wiring to be formed.

[0019] In one aspect of the present invention, a gate electrode layer is formed using side etching, preferably with a recess. A source electrode and a source electrode are formed on the gate electrode layer by using a resist mask having the same structure. The present invention relates to a method for manufacturing an EL display device having a thin film transistor in which a drain electrode layer is formed.

[0020] One embodiment of the present invention is a semiconductor film including a first conductive film, a first insulating film, an impurity semiconductor film, and a second a first resist mask is formed on the second conductive film; and The first insulating film, the semiconductor film, and the impurity semiconductor film are formed by using the first resist mask. A first etching is performed on the conductive film and the second conductive film to remove at least a surface of the first conductive film. a second etching is performed on a portion of the first conductive film to expose a surface of the first insulating film; A gate electrode layer is formed so as to have a width narrower than that of the second conductive film, and a second resist is formed on the second conductive film. a second resist mask is formed, and the second conductive film and the impurity semiconductor are formed using the second resist mask; A third etching is performed on the conductive film and a part of the semiconductor film to form a source electrode and a drain electrode. A thin film transistor is formed by forming a semiconductor layer, a source region and a drain region layer, and a semiconductor layer. The second resist mask is removed, and a second insulating film is formed covering the thin film transistor. a second insulating film to expose a portion of the source electrode and drain electrode layer; An opening is formed in the film, and a first pixel electrode is selectively formed on the opening and the second insulating film. forming an EL layer on the first pixel electrode; and forming a second pixel electrode on the EL layer. The present invention relates to a method for producing an EL display device.

[0021] One embodiment of the present invention is a semiconductor film including a first conductive film, a first insulating film, an impurity semiconductor film, and a second a first resist mask is formed on the second conductive film; and The first insulating film, the semiconductor film, and the impurity semiconductor film are formed by using the first resist mask. A first etching is performed on the conductive film and the second conductive film to remove at least a surface of the first conductive film. a second resist mask is formed on the second conductive film; and After forming a mask, a second etching is performed on a part of the first conductive film to form the first insulating film. A gate electrode layer is formed so as to have a width narrower than that of the film, and the second resist mask is used to form the gate electrode layer. A third etching is performed on the second conductive film, the impurity semiconductor film, and a part of the semiconductor film. The source electrode and drain electrode layers, the source region and drain region layers, and the semiconductor layer a thin film transistor is formed by forming a second resist mask, and the second resist mask is removed. A second insulating film is formed covering the thin film transistor, and the source electrode and drain electrode layers are An opening is formed in the second insulating film so as to expose a portion of the second insulating film. A first pixel electrode is selectively formed on the insulating film, an EL layer is formed on the first pixel electrode, and A method for producing an EL display device, comprising forming a second pixel electrode on the EL layer. .

[0022] One embodiment of the present invention is a semiconductor film including a first conductive film, a first insulating film, an impurity semiconductor film, and a second The conductive films are sequentially laminated, and a first resist mask having a recess is formed on the second conductive film. A first resist mask is formed on the first insulating film, the semiconductor film, and the front surface of the first insulating film. A first etching is performed on the impurity semiconductor film and the second conductive film to form a first conductive film. At least the surface is exposed, and a second etching is performed on a portion of the first conductive film to form the A gate electrode layer is formed so as to have a width narrower than that of the first insulating film, and the first resist mask is The second conductive film is formed by removing the first resist mask from the recessed portion of the first conductive film. While exposing the substrate, a second resist mask is formed, and the second resist mask is used to A third etching is performed on the second conductive film, the impurity semiconductor film, and a part of the semiconductor film to form a semiconductor film. Forming source and drain electrode layers, source and drain region layers, and a semiconductor layer The second resist mask is removed, and the thin film transistor is formed. A second insulating film is formed covering the transistor, and a part of the source electrode and drain electrode layer is exposed. An opening is formed in the second insulating film so as to form a first insulating film on the opening and the second insulating film. a first pixel electrode is selectively formed, an EL layer is formed on the first pixel electrode, and an insulating layer is formed on the EL layer. The method for manufacturing an EL display device is characterized in that a second pixel electrode is formed on the first pixel electrode.

[0023] One embodiment of the present invention is a semiconductor film including a first conductive film, a first insulating film, an impurity semiconductor film, and a second The conductive films are sequentially laminated, and a first resist mask having a recess is formed on the second conductive film. A first resist mask is formed on the first insulating film, the semiconductor film, and the front surface of the first insulating film. A first etching is performed on the impurity semiconductor film and the second conductive film to form a first conductive film. At least the surface is exposed, and the first resist mask is recessed to form the first resist. A second resist mask is then removed while exposing the second conductive film that overlaps the recesses of the resist mask. After forming the second resist mask, a second etching is performed on a part of the first conductive film. forming a gate electrode layer having a width narrower than that of the first insulating film by etching; The second conductive film, the impurity semiconductor film, and the semiconductor film are patterned using a second resist mask. A third etching is performed on a portion of the source electrode and drain electrode layer, the source region and the drain region. A thin film transistor is formed by forming a gate region layer and a semiconductor layer. The mask is removed, a second insulating film is formed covering the thin film transistor, and the source An opening is formed in the second insulating film so as to expose a part of the drain electrode layer and the front electrode layer. A first pixel electrode is selectively formed on the opening and the second insulating film, An EL device comprising: an EL layer formed on the electrode; and a second pixel electrode formed on the EL layer. A method for manufacturing a display device.

[0024] In the above-mentioned method, when the first resist mask has a recess, The first resist mask is preferably formed using a multi-tone mask. By using the above, a resist mask having a recess can be formed in a simple process.

[0025] By applying the method for manufacturing an EL display device having the above-mentioned configuration, An element region is formed, and the second etching is performed to form a substantially equal area from the side of the element region. The side surface of the gate electrode layer can be formed at a distance inward.

[0026] The method for manufacturing an EL display device using the first etching and the second etching of the above configuration In any one of the above, the first etching is performed by dry etching, and the second etching is performed by dry etching. The etching is preferably performed by wet etching. It is preferable to perform the first etching with high accuracy, and the second etching process involves side etching. Dry etching is preferable for high-precision processing, while wet etching is also preferable. Etching utilizes a chemical reaction, so side etching is less likely to occur than with dry etching. This is because it is easy to use.

[0027] In the method for producing an EL display device having the above-mentioned configuration, the second insulating film is formed by a CVD method or a spa An insulating film formed by a tarpaulin method and an insulating film formed by a spin coating method are laminated. It is particularly preferable to form a silicon nitride film by a CVD method or a sputtering method. The first insulating film is formed by a coating method, and the organic resin film is formed by a spin coating method. By forming the thin film transistor in this manner, impurity elements that may affect the electrical characteristics of the thin film transistor can be eliminated. The thin film transistor is protected from the above-mentioned defects, and the flatness of the surface on which the pixel electrode is formed is improved, thereby increasing the yield. It is possible to prevent a decrease in the

[0028] The thin film transistor formed when the above-described manufacturing method of the EL display device is applied is a gate. a gate insulating film covering the gate electrode layer, a semiconductor layer on the gate insulating film, a source region and a drain region on the body layer, a source electrode and a drain electrode, and a cavity is provided in contact with a side surface of the gate electrode layer. The cavity reduces the dielectric constant near the edge of the gate electrode. k) can be achieved.

[0029] The term "film" refers to a non-patterned material formed over the entire surface, and the term "layer" refers to a non-patterned material formed over the entire surface. refers to a pattern formed into a desired shape using a resist mask, etc. The respective layers of the membrane may be used without any particular distinction between membrane and layer.

[0030] In addition, "etching" refers to unintentional etching. It is preferable to carry out the reaction under conditions that minimize the occurrence of ".

[0031] In this specification, the term "heat resistant" means that a film is resistant to heat in a subsequent process. Depending on the degree, the film maintains its shape as a film and maintains the functions and properties required of the film. This means that it is possible.

[0032] Note that the "gate wiring" refers to a wiring connected to a gate electrode of a thin film transistor. The gate wiring is formed by the gate electrode layer. The gate wiring is also called the scanning line. There is a saying.

[0033] In addition, the term "source wiring" refers to a wiring that is connected to one of the source electrode and the drain electrode of a thin film transistor. The source wiring is formed by the source electrode and the drain electrode layer. The source line is sometimes called the signal line.

[0034] Moreover, a "power supply line" refers to a wiring that is connected to a power supply and is maintained at a constant potential. Effect of the Invention

[0035] No new photomask is required for patterning the gate electrode, and thin-film transistors can be fabricated. The number of manufacturing steps can be significantly reduced, and the thin film transistor can be applied to EL display devices. Therefore, the number of steps required to manufacture an EL display device can be significantly reduced.

[0036] More specifically, the number of photomasks can be reduced. It is also possible to fabricate thin film transistors using a photo-aligned mask. This allows for a significant reduction in the number of steps required to manufacture the device.

[0037] In addition, unlike conventional techniques that aim to reduce the number of photomasks, There is no need to go through complicated processes such as strip flow and lift-off. Therefore, the yield is improved. It is possible to greatly reduce the number of steps in the manufacture of an EL display device without degrading the optical performance.

[0038] In addition, conventional techniques aimed at reducing the number of photomasks sacrifice electrical characteristics. However, in one embodiment of the present invention, The number of steps for manufacturing a thin film transistor can be significantly reduced while maintaining the characteristics. Therefore, the number of manufacturing steps for EL display devices can be increased without sacrificing the display quality of the EL display devices. can be reduced in width.

[0039] Furthermore, due to the above effects, the manufacturing costs of the EL display device can be significantly reduced. Note that the thin film transistor according to one embodiment of the present invention has a cavity in contact with an end portion of a gate electrode layer. Therefore, the leakage current occurring between the gate electrode and the drain electrode is small. [Brief description of the drawings]

[0040] [Figure 1] FIG. 2 illustrates an example of a pixel circuit of a display device. [Diagram 2] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Diagram 3] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 4] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Diagram 5] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 6] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 7] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 8] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 9]1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 10] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 11] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 12] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 13] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 14] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 15] 1A to 1C illustrate an example of a method for manufacturing a thin film transistor and a display device. [Figure 16] FIG. 4 is a diagram for explaining a multi-tone mask. [Figure 17] FIG. 4 is a diagram illustrating a connection portion of an active matrix substrate. [Figure 18] FIG. 4 is a diagram illustrating a connection portion of an active matrix substrate. [Figure 19] FIG. 4 is a diagram illustrating a connection portion of an active matrix substrate. [Figure 20] 1A to 1C are diagrams illustrating electronic devices. [Figure 21] 1A to 1C are diagrams illustrating electronic devices. [Figure 22] 1A to 1C are diagrams illustrating electronic devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description, and may be modified in any form without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that various modifications may be made to the details. The present invention should not be construed as being limited to the description of the embodiment shown below. In describing the configuration of the invention using the drawings, the same reference numerals are used in different drawings. In addition, when referring to similar items, the same hatch pattern is used and no particular symbol is attached. In addition, the insulating film is not shown in the top view.

[0042] (Embodiment 1) In this embodiment mode, a method for manufacturing a thin film transistor and a method for manufacturing the thin film transistor using a matrix An example of a method for manufacturing an EL display device having a rectangular array will be described with reference to FIGS. do.

[0043] EL display devices that use thin-film transistors as switching elements (active EL displays) Various pixel circuits for the liquid crystal display (LCD) are being considered. An example of a pixel circuit is shown in FIG. 1, and a method for fabricating a pixel structure using this pixel circuit is described. However, in this embodiment, the pixel circuit of the EL display device is not limited to the configuration shown in FIG. It is not something that can be determined.

[0044] In the pixel structure of the EL display device shown in FIG. 1, a pixel 21 includes a first transistor 11, The semiconductor device includes a second transistor 12, a third transistor 13, a capacitor 14, and a light-emitting element 15. The first to third transistors are n-type transistors. The gate electrode of the first gate electrode is connected to the gate wiring 16, and one of the source electrode and the drain electrode (the first ) is connected to the source wiring 18, and the other of the source electrode and the drain electrode ( The second electrode (hereinafter referred to as the second electrode) is a gate electrode of the second transistor 12 and one of the capacitors 14. The other electrode (hereinafter referred to as the second electrode) of the capacitance element 14 is connected to the first electrode. ) is one of the source electrode and the drain electrode of the second transistor 12 (the first 1. The source electrode and the drain electrode of the third transistor 13 (the first 1, and one electrode (referred to as the first electrode) of the light-emitting element 15. The other of the source electrode and the drain electrode of the second transistor 12 (hereinafter referred to as the second electrode) The source electrode of the third transistor 13 and the The other of the drain electrodes (hereinafter referred to as the second electrode) is connected to a first power supply line 17. The electrode is connected to the gate wiring 16. The other electrode of the light emitting element 15 (hereinafter referred to as the second electrode) ) is connected to a common electrode 20. The first power supply line 17 and the second power supply line 19 The potentials are different.

[0045] The operation of the pixel 21 will be described. When 13 is turned on, the first electrode of the second transistor 12, the first electrode of the light-emitting element 15, The potential of the second electrode of the capacitance element 14 is equal to the potential of the first power supply line 17 (V 17 ) is equal to Here, the potential of the first power supply line 17 (V 17 ) is constant, so the second transistor The potential of the first electrode 12 is constant (V 17 ).

[0046] When the first transistor 11 is selected and turned on by a signal on the gate line 16, The potential of the signal from the signal line 18 (V 18 ) is connected to the second transistor via the first transistor 11. At this time, the potential of the second power supply line 19 (V 19 )but The potential of the first power supply line 17 (V 17 ) is higher than V gs =V 18 -V 17 And then T, V gs If the threshold voltage of the second transistor 12 is greater than the threshold voltage of the second transistor 12, Star 12 turns on.

[0047] Therefore, when the second transistor 12 is operated in the linear region, the source wiring 18 Potential (V 18 ) is changed (for example, to a binary value) to turn on the second transistor 12. That is, by applying a voltage to the EL layer of the light emitting element 15, You can control whether or not to

[0048] When the second transistor 12 is operated in the saturation region, the voltage of the source wiring 18 is Place (V 18 ) can be used to control the amount of current flowing through the light emitting element 15. .

[0049] In this manner, when the second transistor 12 is operated in the linear region, the light-emitting element 1 5, the light emitting element 15 can be turned on or off. Such a driving method is, for example, digital time gray scale driving. Digital time gray scale driving divides one frame into multiple subframes. A driving method is used to control the light emitting state and non-light emitting state of the light emitting element 15 in each subframe. In addition, when the second transistor 12 is operated in the saturation region, The amount of current that flows can be controlled, and the luminance of the light-emitting element 15 can be adjusted.

[0050] Next, a pixel structure to which the pixel circuit shown in FIG. 1 is applied and a method for fabricating the pixel structure will be described below. do.

[0051] 2 to 6 are top views of the thin film transistor according to this embodiment, and FIG. 7 to 9 are diagrams showing the completed state including the formation of pixel electrodes. 10 to 12 are cross-sectional views taken along the line B-B' shown in FIGS. 2 to 6. 13 to 15 are cross-sectional views taken along the line CC' shown in FIGS.

[0052] First, a first conductive film 102, a first insulating film 104, a semiconductor film 106, an insulator film 108, and a silicon substrate 109 are formed on a substrate 100. A pure semiconductor film 108 and a second conductive film 110 are formed. These films are formed as single layers. Alternatively, it may be a laminated film in which a plurality of films are laminated.

[0053] The substrate 100 is an insulating substrate, and may be, for example, a glass substrate or a quartz substrate. In this embodiment mode, a glass substrate is used.

[0054] The first conductive film 102 is formed of a conductive material. Tantalum, molybdenum, chromium, tantalum, tungsten, aluminum, copper, neodymium, Conductive materials such as metal materials such as obium or scandium, or alloy materials that contain these as their main components However, in the subsequent steps (formation of the first insulating film 104, etc.), The heat resistance is necessary to a degree that can be endured in the subsequent steps (etching the second conductive film 110, etc.). It is necessary to select a material that is not etched or corroded. 02 is not limited to any particular material.

[0055] The first conductive film 102 is formed by, for example, a sputtering method or a CVD method (thermal CVD method or It can be formed by methods such as plasma CVD, etc. However, it is limited to certain methods. It is not something that is done.

[0056] The first insulating film 104 is formed of an insulating material. For example, the first insulating film 104 is The insulating layer can be formed using a silicon oxide film, a nitride film, an oxynitride film, a nitride oxide film, or the like. However, like the first conductive film 102, it must be heat resistant and must not be etched or corroded in a later process. In this respect, the first insulating film 104 is made of a material that is not susceptible to the above-mentioned problems. There is no limitation on the material.

[0057] The first insulating film 104 is formed by, for example, a CVD method (thermal CVD method, plasma CVD method, etc.). It can be formed by a method such as deposition (including deposition of a thin film) or sputtering, but is limited to a specific method. It's not something like that.

[0058] The first insulating film 104 functions as a gate insulating film.

[0059] The semiconductor film 106 is formed of a semiconductor material, for example, silane gas. The first conductive layer can be formed of amorphous silicon or the like. Like the conductive film 102, the material must be heat resistant and not be etched or corroded in the subsequent process. In this respect, the semiconductor film 106 is not limited to a specific material. Therefore, germanium or the like may also be used.

[0060] The semiconductor film 106 is formed by, for example, a CVD method (including a thermal CVD method or a plasma CVD method, etc.). ) or sputtering method, etc. However, it is not limited to a specific method. It is not something that can be achieved.

[0061] The semiconductor film 106 is preferably a laminated film of a crystalline semiconductor film and an amorphous semiconductor film. Examples of the crystalline semiconductor film include a polycrystalline semiconductor film and a microcrystalline semiconductor film.

[0062] A polycrystalline semiconductor film is a semiconductor film that is composed of crystal grains and contains many grain boundaries between the crystal grains. The polycrystalline semiconductor film is formed by, for example, a thermal crystallization method or a laser crystallization method. Here, the thermal crystallization method is a method of forming an amorphous semiconductor film on a substrate and heating the substrate to form an amorphous semiconductor film. The laser crystallization method is a method of crystallizing an amorphous semiconductor on a substrate. A semiconductor film is formed, and the amorphous semiconductor film is irradiated with a laser to crystallize the amorphous semiconductor. Alternatively, a crystallization method in which crystallization is achieved by adding a crystallization-promoting element such as nickel is used. In the case where a crystallization promoting element is added to crystallize the semiconductor film, a laser is applied to the semiconductor film. Irradiation is preferably performed.

[0063] Polycrystalline semiconductors are crystallized at temperatures and times that do not cause distortion in the glass substrate. S (Low Temperature Poly Silicon) and crystallize at higher temperatures HTPS (High Temperature Poly Silicon) To be classified.

[0064] A microcrystalline semiconductor film is a semiconductor film that contains crystal grains with a grain size of approximately 2 nm to 100 nm. The entire surface of the film is made up of crystal grains, or there is amorphous semiconductor between the crystal grains. The method for forming a microcrystalline semiconductor film includes forming a crystal nucleus and then A method for growing an amorphous semiconductor film, and forming an insulating film and a metal film in contact with the amorphous semiconductor film. The metal film is irradiated with a laser to generate heat, which causes an amorphous A method for crystallizing a semiconductor may be used. However, for an amorphous semiconductor film, thermal crystallization is used. The term "crystalline semiconductor film" does not include a crystalline semiconductor film formed by a crystallization method or a laser crystallization method.

[0065] The semiconductor film 106 is formed by stacking an amorphous semiconductor film on a crystalline semiconductor film, for example. By using such a laminated film, it is possible to operate transistors in pixel circuits of EL display devices at high speed. Here, the crystalline semiconductor film may be a polycrystalline semiconductor (LTPS or HTPS A film including a crystalline semiconductor film or a microcrystalline semiconductor film may be used.

[0066] By providing an amorphous semiconductor film on a crystalline semiconductor film, the surface of the crystalline semiconductor film is protected from oxidation. In addition, the breakdown voltage can be improved and the off-current can be reduced. This can be done.

[0067] However, as long as the pixel circuit of the EL display device operates normally, the result of the semiconductor film 106 The crystallinity is not particularly limited.

[0068] The impurity semiconductor film 108 is a semiconductor film containing an impurity element that imparts one conductivity type. The semiconductor material gas is formed by adding an impurity element that imparts electrical conductivity. In this case, for example, phosphine (chemical formula: PH 3 ) The insulating layer may be formed of a silicon film containing phosphorus, which is formed by using a silane gas containing Like the first conductive film 102 and the like, the second conductive film 103 must be heat resistant and must not be etched or corroded in subsequent processes. In this respect, the impurity semiconductor film 108 is made of a specific material. The crystallinity of the impurity semiconductor film 108 is not particularly limited. In addition, a part of the semiconductor layer formed by the semiconductor film 106 is not doped. When a region capable of making an ohmic contact is provided by etching or the like, the impurity semiconductor film 108 is There is no need to set it up.

[0069] In this embodiment, in order to manufacture an n-type thin film transistor, one conductive material is added. As the impurity element, arsenic or the like may be used. The lanthanum gas contains arsine (chemical formula: AsH 3 ) at the desired concentration.

[0070] The impurity semiconductor film 108 is formed by, for example, a CVD method (thermal CVD method or plasma CVD method). However, the method is not limited to a specific method. stomach.

[0071] The second conductive film 110 is made of a conductive material (such as the materials listed for the first conductive film 102). Therefore, the first conductive film 102 is formed of a material different from that of the first conductive film 102. Specifically, the second etching process, which will be described later, is used to etch the In addition, similar to the first conductive film 102, a material having heat resistance may be selected. It is necessary to select a material that will not be etched or corroded in the subsequent process. Insofar as this is the case, the second conductive film 110 is not limited to a specific material.

[0072] The second conductive film 110 is formed by, for example, a sputtering method or a CVD method (thermal CVD method or It can be formed by methods such as plasma CVD, etc. However, it is limited to certain methods. It is not something that is done.

[0073] The first conductive film 102, the first insulating film 104, the semiconductor film 106, and the impurities The heat resistance required for the semiconductor film 108 and the second conductive film 110 is 02 is the highest, followed by the second conductive film 110 in the order mentioned above, and the second conductive film 110 is the lowest. When the semiconductor film 106 is an amorphous semiconductor film containing hydrogen, the temperature is set to about 300° C. or higher. Hydrogen in the conductive film is released, and the electrical characteristics change. In subsequent steps, the temperature should preferably not exceed 300°C.

[0074] Next, a first resist mask 112 is formed on the second conductive film 110 (FIG. 7(A), 10(A) and 13(A). Here, the first resist mask 112 has a recess or It is preferable that the resist mask has a convex portion. In other words, the resist mask has a plurality of regions with different thicknesses. The first resist pattern can be called a resist mask consisting of two regions (here, two regions). In the first resist mask 112, the thick regions are called convex portions of the first resist mask 112, and the thin regions are called convex portions of the first resist mask 112. The area is referred to as a recess of the first resist mask 112. However, the present invention is not limited to this. A resist mask having no concave or convex portions may be used.

[0075] In the first resist mask 112, a region in which a source electrode and a drain electrode layer are to be formed is A protrusion is formed in the region, and the semiconductor layer is exposed without having the source electrode and drain electrode layers. A recess is formed in the area to be covered.

[0076] The first resist mask 112 can be formed using a multi-tone mask. Here, the multi-tone mask will be described below with reference to FIG.

[0077] A multi-tone mask is a mask that can perform exposure with multiple levels of light intensity. Representative examples include This refers to a method in which exposure is performed at three levels of light intensity: exposed area, semi-exposed area, and unexposed area. By using a mask, multiple (typically two types) A resist mask having a certain thickness can be formed. Therefore, a multi-tone mask is used. This makes it possible to reduce the number of photomasks.

[0078] 16(A-1) and 16(B-1) show cross-sectional views of a typical multi-tone mask. FIG. 16(A-1) shows a gray-tone mask 140, and FIG. 16(B-1) shows a half-tone mask. 1 shows the mask 145.

[0079] The gray-tone mask 140 shown in FIG. 16(A-1) is formed on a light-transmitting substrate 141. A light-shielding portion 142 formed by a light-shielding film, and a diffraction grating provided by a pattern of the light-shielding film It consists of 143 parts.

[0080] The diffraction grating unit 143 is made up of slits spaced at intervals equal to or less than the resolution limit of the light used for exposure. By providing dots or meshes, the amount of light transmitted is controlled. The slits, dots or meshes provided in the It may be something like that.

[0081] The light-transmitting substrate 141 may be made of quartz or the like. The light-shielding film constituting the diffraction grating portion 143 may be formed using a metal film, and is preferably a chromium film. The insulating layer 11 is made of chromium or chromium oxide.

[0082] When the gray-tone mask 140 is irradiated with light for exposure, the pattern shown in FIG. As shown in FIG. 1, the light transmittance in the area overlapping the light shielding portion 142 is 0%, and the light transmittance in the area overlapping the light shielding portion 142 is 0%. The light transmittance in the area where the diffraction grating portion 143 is not provided is 100%. The light transmittance of the grating portion 143 is in the range of about 10 to 70%, and the slits of the diffraction grating, This can be adjusted by adjusting the spacing of the dots or meshes.

[0083] The halftone mask 145 shown in FIG. 16(B-1) is formed on a light-transmitting substrate 146. A semi-transparent portion 147 formed of a semi-transparent film and a light-shielding portion 148 formed of a light-shielding film It is composed.

[0084] The semi-transmitting portion 147 is made of a material such as MoSiN, MoSi, MoSiO, MoSiON, or CrSi. The light-shielding portion 148 can be formed using a light-shielding film similar to that of a gray-tone mask. The metal film may be formed of chromium or chromium oxide. .

[0085] When the halftone mask 145 is irradiated with light for exposure, the pattern shown in FIG. As shown in FIG. 1, the light transmittance in the area overlapping the light shielding portion 148 is 0%, and the light transmittance in the area overlapping the light shielding portion 148 or The light transmittance in the area where the semi-transparent portion 147 is not provided is 100%. The light transmittance of the portion 147 is generally in the range of 10 to 70%, and the type or shape of the material used to form the portion 147 may vary. This can be adjusted by the thickness of the film to be formed.

[0086] By exposing and developing using a multi-tone mask, a first layer having regions with different film thicknesses is formed. A resist mask 112 can be formed.

[0087] However, the present invention is not limited to this, and the first resist mask may be formed without using a multi-tone mask. As described above, the first resist mask may have no concave or convex portions. It may be a resist mask.

[0088] Next, a first etching is performed using the first resist mask 112. The insulating film 104, the semiconductor film 106, the impurity semiconductor film 108, and the second conductive film 110 are etched. The thin film laminate 114 is formed by patterning using a thin film deposition method (FIGS. 2, 7(B), and 10). 13B). At this time, at least the surface of the first conductive film 102 is exposed. This etching step is called the first etching. The first etching may be performed by dry etching or wet etching. When the etching is performed by dry etching, it can be performed in one step. When the etching is performed by wet etching, the first etching is performed in a plurality of steps. The etching rate differs depending on the type of film to be etched, and Because it is difficult to do.

[0089] The first etching may be performed, for example, by a three-stage dry etching process. 2 Gas and CF 4 Gas and O 2 Etching is performed in a mixture of gases, then Cl 2 Gas only Finally, etching was performed using CHF 3 Etching can be performed using gas only .

[0090] Next, a second etching is performed using the first resist mask 112. The conductive film 102 is patterned by etching to form a gate electrode layer 116 (FIG. 3, see Fig. 7(C), Fig. 10(C), Fig. 13(C). This etching process is called the second etching process. This is called "switching."

[0091] The gate electrode layer 116 is used for a gate electrode of a thin film transistor, a gate wiring, a capacitor element, The gate electrode layer 116A constitutes one of the electrodes and a support portion. The gate wiring, the gate electrode of the first transistor 11, and the gate electrode of the third transistor 13 When written as gate electrode layer 116B, it refers to the electrode layer constituting the second transistor. The gate electrode of the transistor 12 and the electrode layer that constitutes one of the electrodes of the capacitance element 14. When the term "support electrode layer 116C" is used, it refers to the electrode layer that constitutes the support portion. These are collectively referred to as gate electrode layer 116 .

[0092] The second etching is performed on the side surface of the gate electrode layer 116 formed by the first conductive film 102. However, the etching is performed under the conditions that the thin film laminate 114 is formed on the inner side from the side surface. Then, the side surface of the gate electrode layer 116 is formed in contact with the bottom surface of the thin film stack 114. (The width of the gate electrode layer 116 is equal to the width of the thin film stack 114 in the A-A' cross section.) (The etching is performed so that the second conductive film 110 becomes smaller.) The etching rate of the first conductive film 102 is small and the etching rate of the first conductive film 102 is large. In other words, the etching selection of the first conductive film 102 with respect to the second conductive film 110 is performed. The second etching is performed under conditions with a large selectivity. A gate electrode layer 116 can be formed.

[0093] Note that the shape of the side surface of the gate electrode layer 116 is not particularly limited. For example, it may be a tapered shape. The shape of the side surface of the gate electrode layer 116 may be determined by the chemical used in the second etching. It is determined based on the following conditions:

[0094] Here, the etching rate of the second conductive film 110 is small, and the etching rate of the first conductive film "Conditions under which the etching rate for the second conductive film 110 is large" or "Conditions under which the etching rate for the second conductive film 110 is large" The condition for a large etching selectivity of the conductive film 102 is defined as the first and second conditions below. It means something that meets the requirements.

[0095] The first requirement is that the gate electrode layer 116 remain where needed. The necessary area of ​​116 is the area shown by the dotted lines in Figs. 3 to 6. That is, the second After etching, the gate electrode layer 116 becomes a gate wiring, a gate electrode of a transistor, It is necessary that the gate electrode is left so as to form one electrode of the capacitor element. In order for the layers to form the gate wiring, a second etch is performed to prevent these wirings from being broken. As shown in FIG. 3 and FIG. 7, the thin film stack 114 is formed at a distance d 1 It is preferable that the side surface of the gate electrode layer 116 is formed on the inner side by the distance d 1 is the implementer can be set appropriately according to the layout.

[0096] The second requirement is that the minimum width d of the gate wiring formed by the gate electrode layer 116 3 ,and The minimum width d of the source wiring and the power supply line formed by the source electrode and drain electrode layer 120 2The second etch is performed to obtain the source electrode and When the drain electrode layer 120 is etched, the minimum width d 2 Is small This is because the current density of the source wiring and the power supply line becomes excessive, and the electrical characteristics are deteriorated. Therefore, in the second etching, the etching rate of the first conductive film 102 becomes excessively high. The etching is performed under conditions whereby the etching rate of the second conductive film 110 is as small as possible.

[0097] In addition, the minimum width d of the source wiring and the power supply line 2 It is difficult to make the source wiring large. and the minimum width of the power line, d 2 is the minimum width d of the semiconductor layer that overlaps with the source wiring and power supply line 4 By The minimum width of the source wiring and power supply wiring is determined by d 2 In order to increase the minimum width d 4 This is because it is necessary to increase the size of the gate wiring, which makes it difficult to insulate the adjacent gate wiring. The minimum width of the semiconductor layer is d 4 is the interval d 1 It should be smaller than approximately twice the size of the , interval d 1 is the minimum width of the semiconductor layer, d 4 Make it larger than about half of the

[0098] The width of the semiconductor layer that overlaps the source wiring and the power supply line is set to a minimum width d 4 The part that is The second etching is performed by providing the second electrode layer at a necessary location to separate the elements. Therefore, the width of the semiconductor layer is d 4 The gate electrode layer 116 does not remain in the portion overlapping the portion where the gate electrode layer 116 is formed. It is possible to form a pattern with a large area.

[0099] Note that the portion connected to the pixel electrode layer is formed by the source electrode and the drain electrode layer. The width of the electrode is the minimum width d 2 It is preferable to set the above.

[0100] As described above, the second etching is performed under conditions involving side etching. It is very important that the second etching is accompanied by side etching of the first conductive film 102. As a result, not only between adjacent gate wirings formed by the gate electrode layer 116, , which can be patterned to provide desired connections for the elements within the pixel circuit. This is why.

[0101] Here, side etching refers to etching in the thickness direction of the film to be etched (the direction perpendicular to the substrate surface or Not only the direction perpendicular to the surface of the film under the film to be etched, but also the direction perpendicular to the thickness direction ( The direction parallel to the substrate surface or the surface of the film under the film to be etched The edge of the film that is side-etched is removed. The etching rate of the etching gas or chemical used for etching the silver film varies depending on the etching conditions. They are formed into various shapes, but are often formed with curved ends. .

[0102] The gate electrode layer 116C shown in FIG. 3 functions as a support portion for supporting the thin film stack 114. The support portion can be used to facilitate film peeling of the gate insulating film formed above the gate electrode layer. Furthermore, by providing the support portion, the gate can be prevented from peeling off by the second etching. This can prevent the cavity region formed in contact with the base electrode layer 116 from becoming unnecessarily large. By providing the support portion, the thin film laminate 114 is prevented from being destroyed or broken by its own weight. This is preferable because it can prevent the support portion from being damaged and improves the yield. The present invention is not limited to a configuration having a support portion, and the support portion may not be provided.

[0103] As described above, the second etching is preferably performed by wet etching. It is nice.

[0104] When the second etching is performed by wet etching, the first conductive film 102 is Aluminum or molybdenum is formed as the second conductive film 110, and titanium or tungsten is formed as the second conductive film 111. A chemical solution containing nitric acid, acetic acid, and phosphoric acid may be used for etching. The first conductive film 102 is made of molybdenum, and the second conductive film 110 is made of titanium or aluminum. For etching, use a chemical solution containing hydrogen peroxide. good.

[0105] When the second etching is performed by wet etching, it is most preferable to use a wet etching method. The conductive film 102 is a laminated film of molybdenum on aluminum containing neodymium. The second conductive film 110 is made of tungsten, and etching is performed using 2% nitric acid and 2% acetic acid. A chemical solution containing 10% acid and 72% phosphoric acid is used. By using a chemical solution with this composition, The first conductive film 102 is etched without etching the second conductive film 110. The neodymium added to the first conductive film 102 serves to reduce the resistance of aluminum and to improve the hysteresis loop. It is added to prevent cracking.

[0106] In addition, the gate electrode layer 116 is formed to have corners when viewed from above (see FIG. 3). This is because the second etching for forming the gate electrode layer 116 proceeds approximately isotropically. The distance d between the side of the gate electrode layer 116 and the side of the thin film stack 114 is 1 are roughly equal This is because the metal is etched in such a way that

[0107] Next, the first resist mask 112 is recessed to expose the second conductive film 110. Then, a second resist mask 118 is formed. The first resist mask 112 is recessed, The second resist mask 118 may be formed by, for example, an oxygen plasma annealing method. However, the first resist mask 112 is recessed to form a second resist. The method for forming the mask 118 is not limited to this. The region in which the first resist mask 112 is formed roughly corresponds to the region of the protrusions of the first resist mask 112. In this case, the second resist mask 118 is formed after the second etching. However, the present invention is not limited to this. After forming the second resist mask 118, the second etching may be performed. Switching may also be performed.

[0108] In addition, when a multi-tone mask is not used to form the first resist mask 112, The second resist mask 118 may be formed separately using a photomask.

[0109] Next, the second conductive film in the thin film stack 114 is patterned using the second resist mask 118. 110 is etched to form the source and drain electrode layers 120 (FIGS. 4 and 8(a) and 8(b)). 11(D), 14(D). Here, the etching conditions are: Select conditions that do not cause or are unlikely to cause etching or corrosion of films other than 10. It is important to perform the process under conditions that do not cause or are unlikely to cause etching or corrosion of the electrode layer 116. .

[0110] The source electrode and drain electrode layer 120 is a source electrode or The drain electrode, the source wiring, the power supply line, the other electrode of the capacitor element, and the thin film transistor The source electrode and drain electrode layer 1 form an electrode that is connected to one electrode of the light-emitting element. When written as 20A, the source wiring 18 and the source electrode of the first transistor 11 are The source and drain electrode layer 120 When written as B, it refers to the electrode layer constituting the first power line 17. When the first transistor 11 is denoted as a source electrode layer 120C, the first transistor 11 is denoted as a source electrode layer 120C. The other of the input electrodes and the electrode that connects the first transistor 11 and the pixel electrode When the source and drain electrode layer 120D is used, it refers to the second power line. 19, and an electrode constituting one of the source electrode and the drain electrode of the second transistor 12 The source and drain electrode layer 120E refers to the third transistor. The source electrode and the drain electrode of the transistor 13 are both electrode layers. When written as a drain electrode layer 120F, it is the other electrode of the capacitance element 14, the second transistor the other of the source and drain electrodes of the third transistor 12 and the source electrode of the third transistor 13 and the other of the drain electrodes, and an electrode connected from these to one electrode of the light emitting element. This refers to the electrode layer that

[0111] The second resist mask 118A overlaps with the source and drain electrode layer 120A. The second resist mask 118B is a mask for covering the source and drain electrode layers 1 20B, and the second resist mask 118C is a mask for forming the source electrode and the drain electrode. The second resist mask 118D overlaps with the source electrode layer 120C. and the drain electrode layer 120D. The second resist mask 118E is The second resist mask 1 overlaps with the source and drain electrode layers 120E. 18F indicates a portion overlapping with the source and drain electrode layer 120F.

[0112] The second conductive film 110 in the thin film stack 114 is etched by wet etching. Either etching or dry etching may be used.

[0113] Next, the impurity semiconductor film 108 and the upper part of the semiconductor film 106 in the thin film stack 114 ( The back channel portion is etched to form the source and drain regions 122 and the semiconductor layer 1 24 is formed (see FIG. 5, FIG. 8(E), FIG. 11(E), FIG. 14(E)). The etching conditions are as follows: etching and corrosion of the films other than the impurity semiconductor film 108 and the semiconductor film 106. In particular, the gate electrode layer 116 is prevented from being etched or corroded. It is important to carry out the experiment under conditions that do not or are unlikely to cause such a phenomenon.

[0114] In addition, the impurity semiconductor film 108 and the upper part of the semiconductor film 106 in the thin film stack 114 ( The etching of the gate channel portion can be performed by dry etching or wet etching. This can be done.

[0115] Thereafter, the second resist mask 118 is removed, and the thin film transistor is completed (FIG. 6, (See Fig. 8(F), Fig. 11(F), Fig. 14(F). As explained above, the thin-film transistor The pattern can be produced using a single photomask (multi-tone mask).

[0116] The steps described with reference to FIG. 8(F) and FIG. 8(E) are collectively referred to as the third edge. The third etching can be performed in multiple steps, as explained above. That's fine, and you can do it all at once.

[0117] A second insulating film is formed to cover the thin film transistor formed as described above. The second insulating film may be formed only of the first protective film 126. 126 and the second protective film 128 (FIG. 9(G), FIG. 12(G), FIG. 15(G) The first protective film 126 may be formed in the same manner as the first insulating film 104, but is preferably or formed of silicon nitride containing hydrogen or silicon oxynitride containing hydrogen, It prevents impurities such as metals from penetrating and diffusing into the semiconductor layer, thereby causing contamination.

[0118] The second protective film 128 is formed by a method that results in a substantially flat surface. The surface of the second protective film 128 is roughly flattened to form a first pixel electrode layer 8 on the second protective film 128. This is because it is possible to prevent the breakage of the 132. Therefore, the term "approximately flat" used here means However, it is sufficient to achieve the above-mentioned objective, and high flatness is not required. .

[0119] The second protective film 128 is made of, for example, photosensitive polyimide, acrylic, or epoxy resin. The film can be formed by a spin coating method or the like. However, these materials Also, the present invention is not limited to a forming method.

[0120] The second protective film 128 is the above-mentioned protective film formed by a method that results in a substantially flat surface. This is covered with a protective film that prevents moisture from entering or escaping. The protective film for preventing the intrusion and release of moisture is preferably made of silicon nitride, oxynitride, or the like. The insulating layer is preferably made of silicon oxide, aluminum oxide nitride, aluminum nitride, or the like. It is preferable to use a sputtering method as a formation method.

[0121] Next, a first opening 130 and a second opening 131 are formed in the second insulating film (FIG. 9( 12(H), 15(H). The first opening 130 is for forming a source electrode and a drain electrode. The second opening 131 is formed so as to reach at least the surface of the gate electrode layer. The first opening 130 and the second opening 131 are formed so as to reach at least the surface of the electrode layer. The method of forming 131 is not limited to a specific method, and may be performed depending on the diameter of the first opening 130, etc. For example, dry etching is performed by photolithography. In this way, the first opening 130 and the second opening 131 can be formed.

[0122] The first opening 130 is provided so as to reach the source electrode and drain electrode layer 120. As shown in FIG. 6, a plurality of first openings 130A are provided at necessary locations. The first opening 130B is provided on the source and drain electrode layer 120C. The first opening 130C is provided on the drain electrode layer 120B, and the first opening 130C is provided on the source electrode and the drain electrode The first opening 130D is formed on the source and drain electrode layer 120F. It shall be established.

[0123] The second opening 131 is provided so as to reach the gate electrode layer 116. That is, the second opening 131 penetrates not only the second insulating film but also the first insulating film 104, the semiconductor layer The desired portion of 124 is also removed and provided.

[0124] In addition, by forming the openings using photolithography, it is possible to fabricate the device using only one photomask. It will be used.

[0125] Next, the first pixel electrode layer 132 is formed on the second insulating film (FIG. 6, FIG. 9(H), FIG. 1 2(H), FIG. 15(H). The first pixel electrode layer 132 is The source and drain electrode layer 120 or the gate electrode layer 11 is 6. Specifically, the first pixel electrode layer 132 is formed so as to be connected to the first opening 130A, the source electrode and drain electrode layer 120C is connected to the first opening 13 0B, and the source electrode and drain electrode layer 120B is connected to the first opening 130C. and connected to the source and drain electrode layer 120E through a first opening 130D. and is connected to the source and drain electrode layer 120F through the second opening 131. The first pixel electrode layer 132 is formed so as to be connected to the gate electrode layer 116B. The insulating film may be formed as a single layer or as a laminated film having a plurality of films laminated thereon.

[0126] In addition, the first pixel electrode layer 132 is formed by photolithography. You will need to use one mask.

[0127] Since the thin film transistor of the pixel is an n-type transistor, the first pixel electrode layer 1 The cathode 32 is preferably made of a material having a work function of 0.1 to 0.5. Examples of materials with low resistance include Ca, Al, MgAg, and AlLi.

[0128] Next, the partition wall 133 is formed on the side surface (end portion) of the first pixel electrode layer 132 and on the second insulating film. The partition wall 133 has an opening, and the first pixel electrode layer 132 is exposed through the opening. The partition wall 133 is formed using an organic resin film, an inorganic insulating film, or an organic polysiloxane. Specifically, polyimide, polyamide, polyimide amide, acrylic, and benzene are used. It is preferable to form the first pixel using a photosensitive material. An opening is formed on the electrode layer 132, and the sidewall of the opening is formed with a continuous curvature. It is preferable to form the surface so as to have an inclined surface.

[0129] Next, the EL layer 1 is formed so as to contact the first pixel electrode layer 132 at the opening of the partition wall 133. The EL layer 134 may be composed of a single layer or a plurality of layers may be laminated. The EL layer 134 may be formed of a laminated film having at least a light-emitting layer. The light-emitting layer is preferably connected to the second pixel electrode layer 135 via a hole transport layer. stomach.

[0130] Then, a second pixel electrode layer 135 is formed from a material that will become an anode so as to cover the EL layer 134. The second pixel electrode layer 135 corresponds to the common electrode 20 in FIG. The electrode layer 135 can be formed using a light-transmitting conductive material. Examples of conductive materials that have this property include indium tin oxide (ITO), tin oxide, and Indium oxide with tungsten oxide, indium zinc oxide with tungsten oxide, Indium oxide containing titanium, indium tin oxide containing titanium oxide, indium zinc Examples of the material include indium tin oxide and silicon oxide. The formation of the conductive material film may be performed by sputtering or CVD. The method is not limited to the above. The second pixel electrode layer 135 is also formed as a single layer. Alternatively, a laminated film in which a plurality of films are laminated may be used.

[0131] Here, ITO is used as the second pixel electrode layer 135. The first pixel electrode layer 132, the EL layer 134, and the second pixel electrode layer 135 are overlapped. Thus, the light emitting element 136 is formed. The light emitting element 136 corresponds to the light emitting element 15 in FIG. After this, in order to prevent oxygen, hydrogen, moisture, carbon dioxide, etc. from entering the light emitting element 136, It is preferable to form a third protective film 137 on the second pixel electrode layer 135 and the partition wall 133. The third protective film 137 is made of a material that is resistant to moisture, similar to the second protective film 128. Select a material that has the function of preventing the intrusion and release of silicon nitride and silicon oxynitride. It is preferable that the insulating layer 11 is made of aluminum oxynitride, aluminum nitride, or the like. Furthermore, it is preferable that the third protective film is covered with a silicon nitride film, a DLC film, or the like.

[0132] In addition, to prevent exposure to the outside air, a protective film (lamination film, UV-curable resin) It is preferred to provide further packaging (enclosure) using a covering material such as a plastic film. The protective film and cover material should be made of materials that have low gas permeability and little outgassing. It is preferable that

[0133] As described above, the light emitting element of the top emission type EL display device (See FIG. 9(I), FIG. 12(I), and FIG. 15(I). The EL display device of the present embodiment is not limited to the above description, and may have a bottom emission structure (bottom emitter). Dual emission type EL display device or dual emission type EL display device In the bottom emission structure and the double emission structure, the first pixel electrode layer A light-transmitting conductive material may be used for the first pixel electrode layer 132. When the first pixel electrode layer 132 is made of a material that is a polarizing electrode, the first pixel electrode layer 132 is made of, for example, ITO. By forming the first pixel electrode layer 132 in this structure, the light emitting This improves the efficiency of extracting light, making it possible to fabricate a bottom-emission type EL display device. Then, the EL layer 134 is covered with a material that will become a cathode to form a second pixel. The second pixel electrode layer 135 may be formed on the common electrode 20 in FIG. The cathode material has a small work function, such as Ca, Al, MgAg The EL layer 134 and the second pixel electrode layer 135 are formed by a mask. Therefore, the second pixel electrode layer 135 is preferably formed by deposition through a deposition method. It is preferable to form the pixel electrode from a material that can be formed by the above-mentioned method. When the circuit shown in FIG. 1 is used, the first pixel electrode layer 132 is used as an anode, and the second pixel It is preferable that the electrode layer 135 be a cathode.

[0134] The protective film and the like described above are not limited to the above-mentioned materials and forming methods, and may be formed by any method other than those described above. Any film that does not block light and can prevent deterioration or the like may be used.

[0135] Alternatively, in a top emission structure, the first Alternatively, a pixel electrode layer 132A may be formed. In this case, the first pixel electrode layer 132B Only a conductive layer corresponding to the first pixel electrode layer 132C is formed, and a first opening is formed on the conductive layer. An insulating film having a first opening 130D is formed, and a source electrode and a drain electrode are formed through the first opening 130D. The first pixel electrode layer 132A may be formed so as to be connected to the first pixel electrode layer 120F. The first pixel electrode layer 132A is formed so as to include the area in which the element circuit is formed. This allows the light emitting area to be enlarged, enabling a higher definition display.

[0136] Although the organic EL element has been described as the light-emitting element here, inorganic light-emitting elements may also be used. An EL element can also be used.

[0137] Here, the terminal connection portion of the active matrix substrate manufactured by the above process is shown in FIG. 17 to 19.

[0138] 17 to 19 show the structure of the active matrix substrate manufactured by the above process. 1A and 1B are a top view and a cross-sectional view of a terminal connection portion on the gate wiring side and a terminal connection portion on the source wiring side.

[0139] FIG. 17 shows the pixel section at the terminal connection part on the gate line side and the terminal connection part on the source line side. 1 shows a top view of the gate wiring and the source wiring extending from the first power supply line 17 and The second power supply line 19 may be the same as the source line 18. The second pixel electrode layer 135 is not shown in FIG.

[0140] FIG. 18 shows a cross-sectional view taken along the line X-X' in FIG. 17. That is, FIG. 18 shows the gate wiring 18 shows a cross-sectional view of a terminal connection portion on the side of the gate electrode layer 116. In FIG. A terminal portion is connected to the exposed region of the gate electrode layer 116.

[0141] FIG. 19 shows an example of a cross-sectional view taken along the line Y-Y′ in FIG. 17. That is, FIG. An example of a cross-sectional view of a terminal connection portion on the wiring side is shown in FIG. The layer 116 and the source and drain electrode layer 120 are connected to a first pixel electrode layer 132 (at least Also, the first pixel electrode layer 132B or the first pixel electrode layer 132C is connected via the same layer. FIG. 19 shows a gate electrode layer 116 and a source electrode and drain electrode layer 120. Various connection forms are shown. Here, any of these can be used for the terminal connection portion of the EL display device. 19. Alternatively, a connection form other than that shown in FIG. 19 may be used. By connecting the drain electrode layer 120 to the gate electrode layer 116, the height of the connection part of the terminal is approximately It can be made equal.

[0142] The number of openings is not particularly limited to the number shown in FIG. In addition to providing one opening, a plurality of openings may be provided for one terminal. By providing a plurality of openings to the Even if the opening is not well formed for some reason, electrical connection can be achieved through other openings. Furthermore, even if all the openings are formed without any problems, This is preferable because the area can be increased and the contact resistance can be reduced.

[0143] In FIG. 19A, the ends of the first protective film 126 and the second protective film 128 are etched or otherwise removed. , exposing the gate electrode layer 116 and the source and drain electrode layers 120. The first pixel electrode layer 132 (at least the first pixel electrode layer 132) is formed on the exposed area. 32B or the same layer as the first pixel electrode layer 132C) to realize electrical connection. The top view shown in FIG 17 corresponds to the top view of FIG 19(A).

[0144] In addition, the gate electrode layer 116 and the source and drain electrode layers 120 are exposed. The formation of the region can be performed simultaneously with the formation of the first opening 130 and the second opening 131. do.

[0145] In FIG. 19B, a third opening 160 is formed in the first protective film 126 and the second protective film 128. A is provided, and the ends of the first protective film 126 and the second protective film 128 are etched or the like. By removing the gate electrode layer 116 and the source and drain electrode layers 120, The first pixel electrode layer 132 (at least the first pixel electrode layer The electrical connection is realized by forming a second pixel electrode layer (the same layer as the first pixel electrode layer 132B or the first pixel electrode layer 132C). This is manifested.

[0146] The formation of the third opening 160A and the formation of the region in which the gate electrode layer 116 is exposed This can be performed simultaneously with the formation of the first opening 130 and the second opening 131.

[0147] In FIG. 19C, a third opening 160 is formed in the first protective film 126 and the second protective film 128. By providing the B and fourth openings 161, the gate electrode layer 116 and the source electrode and The drain electrode layer 120 is exposed, and the first pixel electrode layer 132 (a small At least the same layer as the first pixel electrode layer 132B or the first pixel electrode layer 132C) is formed. Here, as in Figs. 19(A) and (B), the first The ends of the first protective film 126 and the second protective film 128 are removed by etching or the like. , this area is used as the terminal connection.

[0148] The formation of the third opening 160B and the fourth opening 161 and the gate electrode layer 11 The formation of the exposed region 6 is performed simultaneously with the formation of the first opening 130 and the second opening 131. can be carried out.

[0149] The third opening 160 is a hole for forming a source electrode and a drain electrode, similar to the first opening 130. The fourth opening 161 is provided so as to reach the pole layer 120, similar to the second opening 131. 18 and 19, the insulating layer 114 is formed so as to reach the gate electrode layer 116. The wall 133 and the second pixel electrode layer 135 are shown, but they are not provided at the terminal connection portion. It doesn't have to be.

[0150] The input terminal of this terminal portion (the exposed area of ​​the gate electrode layer 116 in FIG. 19) FPC (Flexible Printed Circuit) is connected. FPC is Wiring is formed on an organic resin film such as polyimide using a conductive film, providing anisotropic conductivity. Paste (Anisotropic Conductive Paste, hereafter referred to as ACP) ACP is connected to the input terminal via a paper that acts as an adhesive. and particles with a diameter of several tens to several hundreds of μm that are plated with gold or the like and have a conductive surface. Particles mixed in the paste are rubbing against the conductive layer on the input terminal and the FPC. By contacting the conductive layer on the terminal connected to the wiring, electrical connection can be achieved. can.

[0151] In this manner, an EL display device can be fabricated.

[0152] As described above, the number of photomasks used is reduced, and the thin film transistor and E This allows the number of steps in manufacturing L display devices to be significantly reduced.

[0153] In addition, the method does not require complicated processes such as backside exposure, resist reflow, and lift-off. The number of manufacturing steps for thin film transistors can be significantly reduced. This makes it possible to significantly reduce the number of steps in the manufacture of an EL display device.

[0154] In addition, the manufacturing process of the thin film transistor can be greatly simplified while maintaining the electrical characteristics of the thin film transistor. can be reduced in width.

[0155] Furthermore, due to the above effects, the manufacturing costs of the EL display device can be significantly reduced.

[0156] (Embodiment 2) This embodiment relates to a display panel or a display device manufactured by the method described in the first embodiment. An electronic device incorporating the device as a display unit will be described with reference to Figs. 20 to 22. Examples of such electronic devices include cameras such as video cameras and digital cameras, Head-mounted displays (goggle-type displays), car navigation, projects Video players, car stereos, personal computers, portable information terminals (mobile computers , mobile phones, electronic books, etc. An example of such is shown in FIG.

[0157] FIG. 20(A) shows a television set. By incorporating an EL display panel into the housing, The television device shown in FIG. 20(A) can be completed. The main screen 223 is formed by a display panel to which the above manufacturing method is applied, and other auxiliary equipment A speaker unit 229, operation switches, etc. are provided.

[0158] As shown in FIG. 20(A), the manufacturing method described in the first embodiment is applied to the housing 221. A display panel 222 is built in, and a receiver 225 is used to receive general television broadcasts. Therefore, the device can be connected to a wired or wireless communication network via a modem 224. Communication can be one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) The television set can be operated by a switch built into the housing or by a separate switch. This can be done by a remote control 226, which also has A display unit 227 for displaying the output information may be provided.

[0159] In addition to the main screen 223, the television device also has a sub-screen 228 on a second display panel. and may be provided with a configuration for displaying the channel, volume, etc.

[0160] FIG. 21 is a block diagram showing the main components of a television device. The display panel includes: A pixel portion 251 is formed. A signal line driving circuit 252 and a scanning line driving circuit 253 are The panel may be mounted using the COG method.

[0161] As for the configuration of other external circuits, on the video signal input side, a signal received by a tuner 254 is A video signal amplifier circuit 255 amplifies the video signal, and outputs the signal a video signal processing circuit 256 which converts the video signals into color signals corresponding to the colors red, green, and blue; It has a control circuit 257 for converting the input specifications of the driver IC. The control circuit 257 outputs signals to the scanning line side and the signal line side. In this case, a signal dividing circuit 258 is provided on the signal line side to divide the input digital signal into an integer number of parts. The power supply may be configured to be supplied via the power supply.

[0162] Of the signals received by the tuner 254, the audio signal is sent to an audio signal amplifier circuit 259. The output of the control circuit 26 is supplied to a speaker 263 via an audio signal processing circuit 260. 1 receives control information for a receiving station (receiving frequency) and volume from an input unit 262, and and sends a signal to the audio signal processing circuit 260.

[0163] Of course, the EL display device according to one embodiment of the present invention is not limited to a television device. The monitors of mobile computers, information display panels at train stations and airports, and street displays The present invention can also be applied to large-area display media such as advertising display boards. By applying the method for producing an EL display device according to the present invention, the productivity of these display media can be improved. It can be done.

[0164] The main screen 223 and the sub-screen 228 are manufactured by the method for manufacturing the display device described in the first embodiment. By using the display panel or display device, the productivity of the television device can be improved. .

[0165] The portable computer shown in FIG. 20B includes a main body 231, a display unit 232, etc. The display portion 232 is a display panel manufactured by the method for manufacturing the display device described in Embodiment 1. The use of a panel or display can increase the productivity of a computer.

[0166] FIG. 22 shows an example of a mobile phone, in which FIG. 22(A) is a front view, FIG. 22(B) is a rear view, and FIG. 22(C) is a front view of the mobile phone 200 when the two housings are slid together. The mobile phone 200 is composed of two housings, a mobile phone 201 and a housing 202. It has both functions as a mobile phone and an information terminal, and can handle a variety of functions in addition to voice calls. It is a so-called smartphone capable of data processing.

[0167] The mobile phone 200 is composed of a housing 201 and a housing 202. The display unit 203, the speaker 204, the microphone 205, the operation keys 206, the pointing device 207, a front camera lens 208; an external connection terminal jack 209; and an input device 207. The housing 202 is equipped with a keyboard 211, an external memory slot, etc. The device is composed of a touch panel 212, a rear camera 213, a light 214, etc. is built into the housing 201.

[0168] In addition to the above configuration, the mobile phone 200 also includes a non-contact IC chip, a small recording device, etc. may be built in.

[0169] The overlapping housings 201 and 202 (shown in FIG. 22(A)) can be slid. By sliding it, it can be deployed as shown in FIG. 22(C). A display panel or a display device to which the manufacturing method of the display device described in Embodiment 1 is applied is assembled. It is possible to embed the display unit 203 and the front camera lens 208 on the same surface. Therefore, it can be used as a videophone. By using it in combination, it is possible to take still images and videos using the rear camera 213 and the light 214. be.

[0170] Using a speaker 204 and a microphone 205, the mobile phone 200 can record voice messages. It can be used as a recording device (audio recorder) or an audio playback device. 6 allows you to make and receive calls, input simple information such as e-mails, and display images on the display unit. It is possible to scroll the screen and move the cursor to select the information to be displayed on the display. It is.

[0171] In addition, when handling a large amount of information, such as when creating documents or using it as a mobile information terminal, It is convenient to use the card 211. Furthermore, the overlapping housings 201 and 202 (FIG. 22 By sliding (A), it can be unfolded as shown in Figure 22(C). When used as an information terminal, the keyboard 211 and the pointing device 207 The external connection terminal jack 209 can be used to connect an AC adapter and a USB It can be connected to various cables such as USB cable, and can be used for charging and connecting to a personal computer, etc. In addition, a recording medium can be inserted into the external memory slot 212 for more data communication. It becomes possible to store and move large amounts of data.

[0172] The rear surface of the housing 202 (FIG. 22(B)) is provided with a rear camera 213 and a light 214. It is possible to take still images and moving images using the display unit 203 as a viewfinder.

[0173] In addition to the above functional configuration, infrared communication function, USB port, TV One Seg reception It may also be equipped with a function, a contactless IC chip, an earphone jack, etc.

[0174] The various electronic devices described in this embodiment are the same as those described in the first embodiment. Since the manufacturing method of the electronic device can be applied to the manufacturing of the electronic device, Productivity can be improved.

[0175] Therefore, the manufacturing costs of these electronic devices can be significantly reduced. [Explanation of symbols]

[0176] 11 First transistor 12 Second transistor 13 The third transistor 14 Capacitive element 15 Light emitting element 16 Gate wiring 17 First power line 18 Source wiring 19 Second power line 20 common electrode 21 pixels 100 Substrates 102 First conductive film 104 First insulating film 106 Semiconductor Film 108 Impurity Semiconductor Film 110 Second conductive film 112 First resist mask 114 Thin Film Laminates 115 Etched first conductive film 116 Gate electrode layer 116A Gate electrode layer 116B Gate electrode layer 116C Gate electrode layer 116D Gate electrode layer 118 Second resist mask 118A Second resist mask 118B Second resist mask 118C Second resist mask 118D Second resist mask 118E Second resist mask 118F Second resist mask 120 Source and drain electrode layers 120A source and drain electrode layer 120B source and drain electrode layers 120C Source and drain electrode layers 120D Source and drain electrode layer 120E Source and drain electrode layers 120F Source and drain electrode layers 122 Source and drain regions 122A Source and drain regions 122B Source and drain regions 122C Source and drain regions 122D Source and drain regions 124 Semiconductor layer 126 First protective film 128 Second Protective Film 130 First opening 130A First opening 130B First opening 130C First opening 130D First opening 131 Second Opening 132 First pixel electrode layer 132A First pixel electrode layer 132B First pixel electrode layer 132C First pixel electrode layer 133 Bulkhead 134 EL layer 135 Second pixel electrode layer 136 Light-emitting element 137 Third Protective Film 140 Gray Tone Mask 141 Substrate 142 Light shielding part 143 Diffraction grating section 145 Halftone Mask 146 Substrate 147 Semi-transparent part 148 Shading part 160 Third Opening 160A Third Opening 160B Third opening 161 Fourth Opening 170 First resist mask 171 Second resist mask 200 Mobile Phones 201 Case 202 Case 203 Display section 204 Speaker 205 Microphone 206 Operation Key 207 Pointing Device 208 Surface camera lens 209 External connection terminal jack 210 Earphone jack 211 Keyboard 212 External memory slot 213 Rear Camera 214 Light 221 Case 222 Display Panel 223 Main screen 224 Modem 225 Receiver 226 Remote Controlled Device 227 Display section 228 Sub Screen 229 Speaker section 231 Main Body 232 Display section 251 Pixel section 252 Signal line driver circuit 253 Scanning line driver circuit 254 Tuner 255 Video signal amplifier circuit 256 Video signal processing circuit 257 Control Circuit 258 Signal splitting circuit 259 Audio signal amplifier circuit 260 Audio signal processing circuit 261 Control circuit 262 Input section 263 Speaker

Claims

[Claim 1] A first conductive film, a first insulating film, a semiconductor film, an impurity semiconductor film, and a second conductive film are sequentially stacked to form the first conductive film, forming a first resist mask on the second conductive film; performing a first etching process on the first insulating film, the semiconductor film, the impurity semiconductor film, and the second conductive film using the first resist mask to expose at least a surface of the first conductive film; performing a second etching process involving side etching on a portion of the first conductive film to form a gate electrode; forming a second resist mask on the second conductive film; a third etching is performed on the second conductive film, the impurity semiconductor film, and a part of the semiconductor film using the second resist mask to form a source electrode, a drain electrode, a source region, a drain region, and a semiconductor layer, thereby forming a thin film transistor; removing the second resist mask and forming a second insulating film covering the thin film transistor; forming an opening in the second insulating film so as to expose a portion of the source electrode and the drain electrode; selectively forming a first pixel electrode on the opening and the second insulating film; forming an EL layer on the first pixel electrode; forming a second pixel electrode on the EL layer.

Images