JP4339000B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device having a circuit formed of a thin film transistor (hereinafter referred to as TFT) and a manufacturing method thereof. For example, the present invention relates to an electronic apparatus in which an electro-optical device typified by a liquid crystal display device or a light emitting device having an OLED is mounted as a component.
[0002]
Note that in this specification, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics, and an electro-optical device, a semiconductor circuit, and an electronic device are all semiconductor devices.
[0003]
[Prior art]
In recent years, a technique for forming a thin film transistor (TFT) using a semiconductor thin film (having a thickness of about several to several hundred nm) formed on a substrate having an insulating surface has attracted attention. Thin film transistors are widely applied to electronic devices such as ICs and electro-optical devices, and development of switching devices for image display devices is urgently required.
[0004]
Conventionally, a liquid crystal display device is known as an image display device. Active matrix liquid crystal display devices are often used because high-definition images can be obtained compared to passive liquid crystal display devices. In an active matrix liquid crystal display device, a display pattern is formed on a screen by driving pixel electrodes arranged in a matrix. Specifically, by applying a voltage between the selected pixel electrode and the counter electrode corresponding to the pixel electrode, optical modulation of the liquid crystal layer disposed between the pixel electrode and the counter electrode is performed. The optical modulation is recognized by the observer as a display pattern.
[0005]
In addition, for a light emitting device using an OLED, a TFT is an essential element for realizing an active matrix driving method. Therefore, in a light emitting device using an OLED, at least a TFT that functions as a switching element and a TFT that supplies current to the OLED are provided in each pixel. A light-emitting element using an organic compound having characteristics such as thin and light weight, high-speed response, and direct current low-voltage driving as a light emitter is expected to be applied to a next-generation flat panel display. In particular, a display device in which light emitting elements are arranged in a matrix is considered to be superior to a conventional liquid crystal display device in that it has a wide viewing angle and excellent visibility.
[0006]
The light-emitting mechanism of the light-emitting element recombines electrons injected from the cathode and holes injected from the anode at the emission center in the organic compound layer by applying a voltage with the organic compound layer sandwiched between a pair of electrodes. Thus, it is said that molecular excitons are formed, and when the molecular excitons return to the ground state, energy is emitted and light is emitted. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.
[0007]
For a light-emitting device formed by arranging such light-emitting elements in a matrix, driving methods such as passive matrix driving (simple matrix type) and active matrix driving (active matrix type) can be used. However, when the pixel density increases, the active matrix type in which a switch is provided for each pixel (or one dot) is considered to be advantageous because it can be driven at a lower voltage.
[0008]
Applications of such active matrix display devices (typically liquid crystal display devices and light-emitting display devices) are expanding, and demands for higher definition, higher aperture ratio, and higher reliability as the screen size increases. Is growing. At the same time, demands for improved productivity and lower costs are increasing.
[0009]
[Problems to be solved by the invention]
Conventionally, when a TFT is manufactured using aluminum as the gate wiring material of the TFT, TFT malfunction and TFT characteristics are caused by the formation of protrusions such as hillocks and whiskers by heat treatment and diffusion of aluminum atoms into the channel formation region. Was causing a decline. Therefore, when using a metal material that can withstand heat treatment, typically a metal element having a high melting point, problems such as increased wiring resistance occur when the screen size is increased, resulting in increased power consumption. And so on.
[0010]
Therefore, an object of the present invention is to provide a structure of a semiconductor device that realizes low power consumption even when the screen is enlarged and a manufacturing method thereof.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention forms an insulating layer and forms a buried wiring (such as Cu, Au, Ag, Ni, chromium, palladium, rhodium, tin, lead, or an alloy thereof) in the insulating layer. Further, after planarizing the surface of the insulating layer, a metal protective film (Ti, TiN, Ta, TaN, etc.) is formed on the exposed portion, and this embedded wiring is used as various wiring (gate wiring) of the light emitting device or the liquid crystal display device. , Source wiring, power supply line, common wiring, etc.) to reduce the resistance of the wiring. According to the present invention, low power consumption can be realized even when the screen size is increased.
[0012]
The configuration of the invention disclosed in this specification is, as shown in FIG.
Between the first substrate having an insulating surface and the second substrate having a light-transmitting property, a first electrode, a layer containing an organic compound in contact with the first electrode, and a layer containing the organic compound A light emitting device having a pixel portion having a plurality of light emitting elements having a second electrode in contact therewith, and a driving circuit having a thin film transistor,
In the light-emitting device, the gate wiring, the source wiring, or the power supply line arranged in the pixel portion is a buried wiring.
[0013]
In the above configuration, the embedded wiring is characterized by being copper, silver, gold, or an alloy thereof that can be plated. The embedded wiring is provided below the thin film transistor.
[0014]
In the above structure, the layer containing an organic compound is a material that emits white light, and is combined with a color filter provided on the second substrate. Alternatively, the layer containing an organic compound is a material that emits monochromatic light, and is characterized by being combined with a color conversion layer or a colored layer provided on the second substrate.
[0015]
The configuration of the invention for realizing the above structure is as follows.
A first step of forming a conductive etching stopper layer on the insulating surface;
A second step of forming a first insulating film covering the etching stopper layer;
Etching the first insulating film to form an opening reaching the etching stopper layer;
Forming a seed, plating, and forming a buried wiring covering the opening;
A fifth step of performing planarization;
A sixth step of forming a second insulating film containing aluminum;
A seventh step of forming a third insulating film on the second insulating film;
An eighth step of forming a semiconductor layer on the third insulating film;
A ninth step of forming a fourth insulating film on the semiconductor layer;
A tenth step of forming a gate electrode on the fourth insulating film;
An eleventh step of forming a wiring connected to the semiconductor layer and a wiring connected to the embedded wiring;
A twelfth step of forming a first electrode;
A method for manufacturing a light-emitting device, comprising: a layer containing an organic compound on the first electrode; and a thirteenth step of forming a second electrode on the layer containing the organic compound.
[0016]
In the structure related to the manufacturing method, the embedded wiring is a power supply line.
[0017]
In the structure related to the manufacturing method, the embedded wiring is copper, silver, gold, or an alloy thereof.
[0018]
Further, in the configuration relating to each of the above manufacturing methods, the etching stopper layer Plating may be performed using as a seed.
[0019]
In addition, as shown in FIG.
A pixel portion including a first electrode, a second electrode, and a liquid crystal material sandwiched between the first substrate having an insulating surface and the second substrate having a light-transmitting property; A liquid crystal display device having a driving circuit having a thin film transistor,
In the liquid crystal display device, the gate wiring or the source wiring arranged in the pixel portion is a buried wiring.
[0020]
In the above structure, the embedded wiring is copper, silver, gold, or an alloy thereof. In the above structure, the embedded wiring is provided below the thin film transistor.
[0021]
The configuration of the invention for realizing the above structure is as follows.
A first step of forming a conductive etching stopper layer on the insulating surface;
A second step of forming a first insulating film covering the etching stopper layer;
Etching the first insulating film to form an opening reaching the etching stopper layer;
Forming a seed, plating, and forming a buried wiring covering the opening;
A fifth step of performing planarization;
A sixth step of forming a second insulating film containing aluminum;
A seventh step of forming a third insulating film on the second insulating film;
An eighth step of forming a semiconductor layer on the third insulating film;
A ninth step of forming a fourth insulating film on the semiconductor layer;
A tenth step of forming a gate electrode on the fourth insulating film;
An eleventh step of forming a source wiring connected to the semiconductor layer and a wiring connecting the buried wiring and the gate electrode;
It is a manufacturing method of the liquid crystal display device characterized by having.
[0022]
In the structure related to the manufacturing method, the embedded wiring is a gate wiring. In the structure related to the manufacturing method, the embedded wiring is copper, silver, gold, or an alloy thereof.
[0023]
Note that the light-emitting element (EL element) includes a layer containing an organic compound (hereinafter, referred to as an EL layer) from which luminescence generated by applying an electric field is obtained, an anode, and a cathode. Luminescence in an organic compound includes light emission (fluorescence) when returning from a singlet excited state to a ground state and light emission (phosphorescence) when returning from a triplet excited state to a ground state, which are produced according to the present invention. The light emitting device can be applied to either light emission.
[0024]
The layer containing an organic compound has a laminated structure. Typically, a stacked structure of a hole transport layer / a light emitting layer / an electron transport layer is provided on the anode. This structure has very high luminous efficiency, and most of the light emitting devices that are currently under research and development employ this structure. In addition, a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer, or a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer / an electron injection layer are sequentially laminated on the anode. Good structure. You may dope a fluorescent pigment | dye etc. with respect to a light emitting layer. These layers may all be formed using a low molecular weight material, or may be formed using a high molecular weight material. Note that in this specification, all layers provided between a cathode and an anode are collectively referred to as a layer containing an organic compound (EL layer). Therefore, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer are all included in the EL layer. The layer containing an organic compound (EL layer) may also contain an inorganic material such as silicon.
[0025]
In the light emitting device of the present invention, the screen display driving method is not particularly limited, and for example, a dot sequential driving method, a line sequential driving method, a surface sequential driving method, or the like may be used. Typically, a line sequential driving method is used, and a time-division gray scale driving method or an area gray scale driving method may be used as appropriate. The video signal input to the source line of the light-emitting device may be an analog signal or a digital signal, and a drive circuit or the like may be designed in accordance with the video signal as appropriate.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0027]
Here, FIG. 1 shows an example in which a buried wiring and a TFT are formed.
[0028]
First, the etching stopper layer 102 is formed over the substrate 100 having an insulating surface. As the etching stopper layer 102, Ni, Ti, W, WSi _X Alternatively, an element selected from Al, Mo, Ta, Cr, or Mo, a film mainly containing an alloy material or compound material containing the element as a main component, or a stacked film thereof may be used. The etching stopper layer 102 can also be used as a seed layer (cathode by plating method) for an electrolytic plating process to be performed later. Next, an insulating film 101 containing silicon as a main component covering the etching stopper layer 102 is formed. (Fig. 1 (A))
[0029]
Next, patterning is performed, and the insulating film 101 is selectively etched to form openings (grooves) that reach the etching stopper layer 102. Next, after forming the first barrier layer 103, electrolytic plating is performed to form a low-resistance metal film having a sufficient thickness in the opening (groove). The electrolytic plating process is a method in which a direct current is passed through an aqueous solution containing metal ions to be formed by a plating method to form a metal film on the cathode surface. As the metal to be plated, a material having low electrical resistance, such as copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof can be used. The thickness of the metal film formed in the electrolytic plating process can be appropriately set by the practitioner by controlling the current density and time. Since the electrical resistance of copper is very low, an example in which copper (Cu) capable of electrolytic plating is used as the low resistance metal film is shown here. It is desirable to form a seed before plating. The first barrier layer 103 is a copper diffusion preventing layer that diffuses quickly in an insulating film containing silicon oxide as a main component, that is, a barrier metal, and has a specific resistance value of about 300 to 500 μΩcm or less. (WN _X , TaN _X TiSi _X N _Y , WSi _X N _Y , TaSi _X N _Y Etc.) is preferable. Further, since copper has poor adhesion with an insulating film containing silicon oxide as a main component, it is useful to form the first barrier layer 103 with good adhesion.
[0030]
Next, by performing a planarization process represented by a chemical mechanical polishing method (hereinafter referred to as a CMP method), copper and the first barrier layer are left only in the openings (grooves), and unnecessary portions are removed. Embedded wirings (hereinafter referred to as embedded wirings) 104a and 104b are formed. (Fig. 1 (B))
[0031]
Next, a second barrier layer 106 is formed to increase the oxidation resistance of the exposed copper. The second barrier layer 106 is also useful as a copper diffusion prevention layer that diffuses quickly in an insulating film containing silicon oxide as a main component, and is a silicon nitride film or a metal material (TiN, NbN, WN). _X , TaN _X TiSi _X N _Y , WSi _X N _Y , TaSi _X N _Y Etc.) is preferable. Further, since copper has poor adhesion to an insulating film containing silicon oxide as a main component, it is useful to form the second barrier layer 106 with good adhesion.
[0032]
Next, AlN is used as a base insulating film for preventing impurity diffusion into the TFT formed later. _X O _Y The layer 107 shown by is formed. AlN _X O _Y The layer 107 shown by the above may be formed by introducing oxygen, nitrogen, or a rare gas from the gas introduction system by an RF sputtering method using a target made of AlN or Al. AlN _X O _Y In the layer represented by the above, it may be in a range containing several atm% or more, preferably 2.5 atm% to 47.5 atm%, and oxygen is 47.5 atm% or less, preferably 0.01 to less than 20 atm%. I just need it.
[0033]
Next, a base insulating film 108 including a stack of insulating films such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed. Although a two-layer structure is used here as the base insulating film 108, a single-layer film of the insulating film or a structure in which two or more layers are stacked may be used. As the first layer 108a of the base insulating film, a plasma CVD method is used, and SiH _Four , NH _Three And N ₂ A silicon oxynitride film formed using O as a reaction gas is formed to a thickness of 10 to 200 nm (preferably 50 to 100 nm). Here, a silicon oxynitride film (composition ratio: Si = 32%, O = 27%, N = 24%, H = 17%) with a thickness of 50 nm is formed. Next, as the second layer 108b of the base insulating film, a plasma CVD method is used, and SiH _Four And N ₂ A silicon oxynitride film formed using O as a reaction gas is formed to a thickness of 50 to 200 nm (preferably 100 to 150 nm). Here, a 100-nm-thick silicon oxynitride film (composition ratio Si = 32%, O = 59%, N = 7%, H = 2%) is formed. (Figure 1 (C))
[0034]
Next, a semiconductor layer is formed over the base film. The semiconductor layer is formed by forming a semiconductor film having an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, etc.), and then known crystallization treatment (laser crystallization method, thermal crystallization method). Or a crystalline semiconductor film obtained by performing a thermal crystallization method using a catalyst such as nickel) is formed into a desired shape by patterning. The semiconductor layer is formed with a thickness of 25 to 80 nm (preferably 30 to 60 nm). There is no limitation on the material of the crystalline semiconductor film, but it is preferably formed of silicon or a silicon germanium alloy.
[0035]
When a crystalline semiconductor film is formed by laser crystallization, a pulse oscillation type or continuous emission type excimer laser, YAG laser, YVO _Four A laser can be used. When these lasers are used, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly collected by an optical system and irradiated onto a semiconductor film. Crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 Hz and the laser energy density is 100 to 400 mJ / cm. ² (Typically 200-300mJ / cm ² ). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is 1 to 10 kHz, and the laser energy density is 300 to 600 mJ / cm. ² (Typically 350-500mJ / cm ² ) Then, when the laser beam condensed linearly with a width of 100 to 1000 μm, for example, 400 μm is irradiated over the entire surface of the substrate, the superposition ratio (overlap ratio) of the linear laser light at this time is 80 to 98%. Good.
[0036]
Next, the surface of the semiconductor layer is washed with an etchant containing hydrofluoric acid to form a gate insulating film 109 that covers the semiconductor layer. The gate insulating film 109 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by using a plasma CVD method or a sputtering method. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N = 7%, H = 2%) is formed to a thickness of 115 nm by plasma CVD. Needless to say, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.
[0037]
Next, after cleaning the surface of the gate insulating film 109, the gate electrode 110 or the connection electrode is formed. In addition, before forming the gate electrode 110, a contact hole reaching the embedded wirings 104a and 104b is formed, and the gate electrode 110 in contact with the embedded wiring 104b or a connection electrode in contact with the embedded wiring 104a is formed to make electrical connection. Do.
[0038]
Next, an impurity element imparting p-type conductivity to the semiconductor (such as B), here boron, is added as appropriate, so that the source region 111 and the drain region 112 are formed. After the addition, heat treatment, intense light irradiation, or laser light irradiation is performed to activate the impurity element. Simultaneously with activation, plasma damage to the gate insulating film and plasma damage to the interface between the gate insulating film and the semiconductor layer can be recovered. In particular, in an atmosphere of room temperature to 300 ° C., it is very effective to activate the impurity element by irradiating the second harmonic of the YAG laser from the front surface or the back surface. A YAG laser is a preferred activation means because it requires less maintenance.
[0039]
In the subsequent steps, an interlayer insulating film 113 made of an organic material or an inorganic material is formed, hydrogenated, and then contact holes reaching the source region, the drain region, or the connection electrode are formed. Next, a source electrode (wiring) 115 and a drain electrode 114 are formed to complete a TFT having a buried wiring (p-channel TFT). Here, an example in which the buried wiring and the drain electrode 114 are connected through the connection electrode formed simultaneously with the gate electrode is shown. However, the contact reaching the buried wiring without using the connection electrode. After forming the hole, the drain electrode may be formed.
[0040]
The TFTs having the embedded wirings 104a and 104b obtained by the above-described processes are various semiconductor devices such as TFTs (current control TFTs) of light emitting devices as shown in FIG. 2 and liquid crystal display devices as shown in FIG. It can be used for a pixel TFT.
[0041]
Here, although the embedded wiring 104b connected to the gate electrode and the embedded wiring 104a connected to the drain electrode are illustrated, there is no particular limitation, and various wirings such as a source wiring, a lead wiring, and a power supply are shown. The resistance of the wiring can be reduced by using it for a line, a capacitor wiring or the like.
[0042]
Further, the present invention is not limited to the TFT structure of FIG. 1E, and if necessary, a lightly doped drain (LDD) having an LDD region between a channel formation region and a drain region (or source region). ) Structure may be used. In this structure, a region to which an impurity element is added at a low concentration is provided between a channel formation region and a source region or a drain region formed by adding an impurity element at a high concentration, and this region is referred to as an LDD region. I'm calling. Further, a so-called GOLD (Gate-drain Overlapped LDD) structure in which an LDD region is disposed so as to overlap with a gate electrode through a gate insulating film may be employed.
[0043]
In addition, although a p-channel TFT has been described here, an n-type impurity element (P, As, etc.) is used instead of the p-type impurity element. n Needless to say, a channel TFT can be formed.
[0044]
Although the top gate type TFT has been described as an example here, the present invention can be applied regardless of the TFT structure. For example, it can be applied to a bottom gate type (reverse stagger type) TFT or a forward stagger type TFT. Is possible.
[0045]
The present invention having the above-described configuration will be described in more detail with the following examples.
[0046]
(Example)
[Example 1]
In this embodiment, an example in which the main part of the power supply line of the light emitting device is embedded wiring is shown in FIGS.
[0047]
First, according to the above embodiment, an etching stopper layer and an insulating film mainly composed of silicon covering the etching stopper layer are formed on a substrate having an insulating surface, and the insulating film is selectively etched to form an etching stopper. After forming an opening (groove) reaching the layer and forming the first barrier layer, electrolytic plating is performed to form a low-resistance metal film having a sufficient thickness in the opening (groove). Next, a planarization process represented by a chemical mechanical polishing method (hereinafter referred to as a CMP method) is performed, leaving copper and the first barrier layer only in the opening (groove), and removing unnecessary portions to embed the mold. The wiring is formed. A top view at this stage is shown in FIG. 3, and a cross-sectional view taken along a dotted line xx ′ corresponds to FIG. In FIG. 3, reference numeral 12 denotes a pixel portion, 13 denotes a source side driver circuit, and 14 and 15 denote regions where gate side driver circuits are arranged. As shown in FIG. 3, connection electrode pads are provided at the corners of the substrate at the end portions of the power supply lines 16 to allow current to flow from an external power source when electrolytic plating is performed. In this embodiment, since the monochromatic light emitting elements are arranged in a matrix, the power supply line 16 is common to each pixel, and the patterns are connected so as to be all conductive.
[0048]
For simplification, only eight power supply lines 16 are shown. However, in actuality, when the number of pixels is m × n (m rows and n columns), m power supply lines are provided. Alternatively, the number of spare wirings for increasing the uniformity of electrolytic plating is one or two.
[0049]
Next, in order to increase the oxidation resistance of the exposed copper, a second barrier layer is formed, and further, AlN is used as a base insulating film. _X O _Y Then, a base insulating film formed by stacking insulating films such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed. Next, the crystalline semiconductor film is patterned into a desired shape to form a semiconductor layer, and a gate insulating film covering the semiconductor layer is formed.
[0050]
Next, after forming a contact hole reaching the buried wiring, a gate wiring, a terminal electrode, and a routing electrode are formed on the gate insulating film. This routing electrode is an electrode provided between the source side driving circuit 13 and the pixel portion 12 and arranged so that a source wiring to be formed later does not overlap with the routing wiring (wiring connected to the cathode or anode of the light emitting element) 17. is there. A plurality of terminal electrodes are provided at the end of the substrate, some of which are connected to power supply lines which are embedded wirings. FIG. 4 is a top view at this stage.
[0051]
Next, an impurity element that imparts p-type conductivity (such as B) or an impurity element that imparts n-type conductivity (such as P or As) to the semiconductor is added as appropriate to form source and drain regions. Next, heat treatment, intense light irradiation, or laser light irradiation is performed to activate the added impurity element. Next, after forming an interlayer insulating film and performing hydrogenation, contact holes reaching the source region, the drain region, the lead-out electrode, the terminal electrode, or the buried wiring are formed.
[0052]
Next, a source electrode (wiring), a drain electrode, or a connection electrode is formed to complete various TFTs. At the stage where the above steps are completed, in the pixel portion 12, the source region and the power supply line are electrically connected, and a connection electrode (not shown here) in contact with the drain region is formed. In the driver circuit, a source electrode (wiring) in contact with the source region and a drain electrode in contact with the drain region are formed. In the terminal portion, a source wiring in contact with a certain terminal electrode and a routing wiring (wiring connected to the cathode or anode of the light emitting element) 17 in contact with another terminal electrode are formed. A lead wiring (wiring connected to the cathode or anode of the light emitting element) 17 is provided between the driving circuit and the pixel portion. FIG. 5 is a top view at this stage.
[0053]
Next, in the pixel portion, the first electrodes 19 in contact with the connection electrodes in contact with the drain region are arranged in a matrix. The first electrode 19 serves as an anode or a cathode of the light emitting element. Next, an insulator (referred to as a bank, a partition, a barrier, a bank, or the like) that covers the end portion of the first electrode 19 is formed. Next, a layer 10 containing an organic compound is formed in the pixel portion, and a second electrode 11 is formed thereon to complete the light emitting element. The second electrode 11 serves as a cathode or an anode of the light emitting element. Note that the second electrode 11 is in contact with and electrically connected to the lead wiring 17 in a region between the pixel portion and the source side driver circuit.
[0054]
Next, the substrate and the sealing material (translucent substrate here) 30 are bonded to each other with the sealing material 31. FIG. 6 is a top view at this stage. Further, a protective film made of a silicon nitride film, a silicon oxynitride film, or a DLC (diamond-like carbon) film may be formed over the second electrode 11 in order to block outside air. Finally, an FPC (flexible printed circuit) for connecting to an external circuit is attached to the terminal electrode.
[0055]
The active matrix light emitting device is completed through the above steps.
[0056]
Note that an active matrix light-emitting device having a TFT can have two structures in the light emission direction. One is a structure in which light emitted from the light emitting element is emitted through the second electrode and enters the observer's eyes. In this case, the observer can recognize the image from the second electrode side. The other is a structure in which light emitted from the light-emitting element is emitted through the first electrode and the substrate and enters the observer's eyes.
[0057]
As shown in FIG. 2A, in the case where light emitted from the light-emitting element is emitted through the second electrode and enters the observer's eyes, the second electrode 11 (the electrode in FIG. 2A) is used. 119) preferably uses a light-transmitting material.
[0058]
For example, when the first electrode 19 (the electrode 117 in FIG. 2A) is used as an anode, the material of the first electrode 19 is a metal having a high work function (Pt, Cr, W, Ni, Zn, Sn, In) and an end portion is covered with an insulator (referred to as a bank, partition wall, barrier, bank, etc.) 116, and then a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution acting as a hole injection layer (PEDOT / PSS) is applied to the entire surface and baked, and then a luminescent center dye (1,1,4,4-tetraphenyl-1,3-butadiene (TPB), 4-dicyanomethylene-2-acting as a luminescent layer. After coating and baking the whole surface with a methyl-6- (p-dimethylamino-styryl) -4H-pyran (DCM1), Nile Red, Coumarin 6 etc.) doped polyvinylcarbazole (PVK) solution Work metal having a low function (Li, Mg, Cs) and a thin film comprising, the laminated transparent conductive film on (ITO (indium oxide-tin oxide alloy), indium oxide-zinc oxide alloy (In ₂ O _Three The second electrode 11 (the electrode 119 in FIG. 2A) formed of a stack of —ZnO), zinc oxide (ZnO), or the like may be formed as a cathode. Note that in FIG. 2A, an auxiliary electrode 120 is provided over the insulator 116 in order to reduce the resistance of the cathode. The light-emitting element thus obtained emits white light. PEDOT / PSS uses water as a solvent and does not dissolve in organic solvents. Therefore, when PVK is applied from above, there is no fear of redissolving. Further, since PEDOT / PSS and PVK have different solvents, it is preferable not to use the same film forming chamber. Note that although an example in which the layer 10 including an organic compound (118 in FIG. 2A) is formed by coating is shown here, the present invention is not particularly limited, and the layer 10 may be formed by an evaporation method.
[0059]
In the above example, an example in which an organic compound layer is stacked as shown in FIG. 7B is shown, but the organic compound layer can be a single layer as shown in FIG. 7A. For example, an electron transporting 1,3,4-oxadiazole derivative (PBD) may be dispersed in hole transporting polyvinyl carbazole (PVK). Further, white light emission can be obtained by dispersing 30 wt% PBD as an electron transporting agent and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red). Further, as shown in FIG. 7C, a layer made of a high molecular material and a layer made of a low molecular material may be stacked as the organic compound layer.
[0060]
The organic compound film is formed between the anode and the cathode, and the holes injected from the anode and the electrons injected from the cathode are recombined in the organic compound film, so that the organic compound film emits white light. Is obtained.
[0061]
It is also possible to obtain white light emission as a whole by appropriately selecting an organic compound film emitting red light, an organic compound film emitting green light, or an organic compound film emitting blue light and mixing them in layers.
[0062]
There are various methods for forming a light emitting element that emits white light to achieve full color display. For example, as shown in FIG. 8A, there is a method of obtaining red, green, and blue light emission by passing the obtained white light emission through a color filter (hereinafter referred to as a color filter method).
[0063]
A color provided with a colored layer (R) that absorbs light other than red light, a colored layer (G) that absorbs light other than green light, and a colored layer (B) that absorbs light other than blue light in the direction in which the organic compound film emits white light. By forming the filter, white light emission from the light emitting element can be separated and obtained as red light emission, green light emission, and blue light emission. In the case of the active matrix type, a TFT is formed between the substrate and the color filter. In the color filter, a light shielding layer is provided between the colored layers, and when the screen is enlarged, it is preferable to include a desiccant in the light shielding layer.
[0064]
In addition, the colored layer (R, G, B) can use a simplest stripe pattern, an oblique mosaic arrangement, a triangular mosaic arrangement, an RGBG four-pixel arrangement, or an RGBW four-pixel arrangement.
[0065]
An example of the relationship between the transmittance and wavelength of each colored layer using a white light source (D65) is shown in FIG. The colored layer constituting the color filter is formed using a color resist made of an organic photosensitive material in which a pigment is dispersed. FIG. 10 shows the color reproduction range when white light emission and a color filter are combined as chromaticity coordinates. The chromaticity coordinates of white light emission are (x, y) = (0.34, 0.35). FIG. 10 shows that the color reproducibility as a full color is sufficiently secured.
[0066]
In this case, even if the luminescent color obtained is different, all the organic compound films exhibiting white luminescence are formed, so that it is not necessary to separately form the organic compound film for each luminescent color. Further, a circularly polarizing plate that prevents specular reflection can be omitted.
[0067]
Next, a CCM method (color changing mediums) realized by combining a blue light emitting element having a blue light emitting organic compound film and a fluorescent color conversion layer will be described with reference to FIG.
[0068]
In the CCM method, blue light emitted from a blue light emitting element excites a fluorescent color conversion layer, and color conversion is performed in each color conversion layer. Specifically, the color conversion layer converts blue to red (B → R), the color conversion layer converts blue to green (B → G), and the color conversion layer converts blue to blue (B → B). ) (Note that the conversion from blue to blue is not necessary) to obtain red, green and blue light emission. Also in the case of the CCM method, the active matrix type has a structure in which TFTs are formed between the substrate and the color conversion layer.
[0069]
In this case, it is not necessary to form the organic compound film separately. Further, a circularly polarizing plate that prevents specular reflection can be omitted.
[0070]
Further, when the CCM method is used, since the color conversion layer is fluorescent, it is excited by external light and has a problem of lowering the contrast. Therefore, a color filter is attached as shown in FIG. To increase the contrast.
[0071]
Here, an external view of the entire active matrix light-emitting device will be described with reference to FIG. 11A is a top view illustrating the light-emitting device, and FIG. 11B is a cross-sectional view taken along line AA ′ in FIG. 11A. Reference numeral 901 indicated by a dotted line denotes a source signal line driver circuit, 902 denotes a pixel portion, and 903 denotes a gate signal line driver circuit. Reference numeral 904 denotes a sealing substrate, reference numeral 905 denotes a sealant, and the inside surrounded by the sealant 905 is a space 907.
[0072]
Note that reference numeral 908 denotes wiring for transmitting signals input to the source signal line driver circuit 901 and the gate signal line driver circuit 903, and a video signal and a clock signal are received from an FPC (flexible printed circuit) 909 serving as an external input terminal. receive. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.
[0073]
Next, a cross-sectional structure is described with reference to FIG. A driver circuit and a pixel portion are formed over the substrate 910. Here, a source signal line driver circuit 901 and a pixel portion 902 are shown as the driver circuits.
[0074]
Note that as the source signal line driver circuit 901, a CMOS circuit in which an n-channel TFT 923 and a p-channel TFT 924 are combined is formed. The TFT forming the driving circuit may be formed by a known CMOS circuit, PMOS circuit or NMOS circuit. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not always necessary, and the driver circuit may be formed outside the substrate.
[0075]
The pixel portion 902 is formed by a plurality of pixels including a switching TFT 911, a current control TFT 912, and a first electrode (anode) 913 electrically connected to the drain thereof. A buried wiring 930 is electrically connected to the source of the current control TFT 912.
[0076]
An insulating layer 914 is formed on both ends of the first electrode (anode) 913, and a layer 915 containing an organic compound is formed on the first electrode (anode) 913. Further, a second electrode (cathode) 916 is formed over the layer 915 containing an organic compound. Thus, a light-emitting element 918 including the first electrode (anode) 912, the layer 915 containing an organic compound, and the second electrode (cathode) 916 is formed. Here, since the light-emitting element 918 emits white light, a color filter including a colored layer 931 and a BM 932 (overcoat layer is not shown here for simplification) is provided.
[0077]
The second electrode (cathode) 916 also functions as a wiring common to all pixels, and is electrically connected to the FPC 909 via the connection wiring 908. In addition, a third electrode (auxiliary electrode) is formed over the insulating layer 914, and the resistance of the second electrode is reduced.
[0078]
In addition, in order to seal the light emitting element 918 formed over the substrate 910, the sealing substrate 904 is attached with a sealant 905. Note that a spacer made of a resin film may be provided in order to secure a space between the sealing substrate 904 and the light-emitting element 918. A space 907 inside the sealing agent 905 is filled with an inert gas such as nitrogen. Note that an epoxy resin is preferably used as the sealant 905. In addition, the sealant 905 is desirably a material that does not transmit moisture and oxygen as much as possible. Furthermore, a substance having an effect of absorbing oxygen and water may be contained in the space 907.
[0079]
Further, in this embodiment, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like is used as a material constituting the sealing substrate 904 as a material constituting the sealing substrate 904. be able to. In addition, after the sealing substrate 904 is bonded using the sealing agent 905, the sealing substrate 904 can be further sealed with a sealing agent so as to cover the side surface (exposed surface).
[0080]
By encapsulating the light emitting element in the space 907 as described above, the light emitting element can be completely blocked from the outside, and a substance that promotes deterioration of the organic compound layer such as moisture and oxygen can be prevented from entering from the outside. Can do. Therefore, a highly reliable light-emitting device can be obtained.
[0081]
On the other hand, as shown in FIG. 2B, when the light emitted from the light-emitting element is emitted through the first electrode and the substrate and enters the eyes of the observer, the first electrode 19 (FIG. 2B The electrode 117) in A) is preferably made of a light-transmitting material.
[0082]
For example, when the first electrode 19 (electrode 117 in FIG. 2B) is used as an anode, a transparent conductive film (ITO (indium tin oxide alloy), indium oxide zinc oxide alloy) is used as the material of the first electrode 19. (In ₂ O _Three -ZnO), zinc oxide (ZnO) or the like is used, and an end portion is covered with an insulator (referred to as a bank, partition wall, barrier, bank, or the like) 116, and then a layer 118 containing an organic compound is formed thereon. Metal film (MgAg, MgIn, AlLi, CaF ₂ And the second electrode 11 (electrode 119 in FIG. 2B) made of an alloy such as CaN, or a film formed by co-evaporation of an element belonging to Group 1 or Group 2 of the periodic table and aluminum. What is necessary is just to form. In forming the cathode, a resistance heating method using vapor deposition may be used, and the cathode may be selectively formed using a vapor deposition mask.
[0083]
This embodiment can be freely combined with the embodiment mode.
[0084]
[Example 2]
Here, an example in which the main part of the gate wiring of the liquid crystal display device is a buried wiring is shown in FIGS.
[0085]
First, according to the above embodiment, an etching stopper layer and an insulating film mainly composed of silicon covering the etching stopper layer are formed on a substrate having an insulating surface, and the insulating film is selectively etched to form an etching stopper. After forming an opening (groove) reaching the layer and forming the first barrier layer, electrolytic plating is performed to form a low-resistance metal film having a sufficient thickness in the opening (groove). Next, a planarization process represented by a chemical mechanical polishing method (hereinafter referred to as a CMP method) is performed, leaving copper and the first barrier layer only in the opening (groove), and removing unnecessary portions to embed the mold. The wiring is formed.
[0086]
Next, in order to increase the oxidation resistance of the exposed copper, a second barrier layer is formed, and further, AlN is used as a base insulating film. _X O _Y Then, a base insulating film formed by stacking insulating films such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed. Next, the crystalline semiconductor film is patterned into a desired shape to form a semiconductor layer, and a gate insulating film covering the semiconductor layer is formed.
[0087]
Next, after forming a contact hole reaching the buried wiring, a gate electrode and a terminal electrode are formed on the gate insulating film. Note that the gate electrode is connected to the buried wiring, and the resistance of the gate wiring is reduced. A plurality of terminal electrodes are provided at the end of the substrate.
[0088]
Next, an impurity element that imparts p-type conductivity (such as B) or an impurity element that imparts n-type conductivity (such as P or As) to the semiconductor is added as appropriate to form source and drain regions. Next, heat treatment, intense light irradiation, or laser light irradiation is performed to activate the added impurity element. Next, an interlayer insulating film is formed, hydrogenated, and contact holes reaching the source region, the drain region, and the terminal electrode are formed.
[0089]
Next, a source electrode (wiring) 55 or a drain electrode is formed to complete various TFTs. When the above steps are completed, in the pixel portion 52, the drain region and the drain electrode are electrically connected, and the source region and the source electrode (wiring) are electrically connected. In the driver circuit, a source electrode (wiring) in contact with the source region and a drain electrode in contact with the drain region are formed. In the terminal portion, a source wiring that contacts a certain terminal electrode is formed. Next, in the pixel portion, pixel electrodes 59 in contact with the connection electrodes in contact with the drain region are arranged in a matrix. FIG. 13 is a top view at this stage. In FIG. 13, reference numeral 52 denotes a pixel portion, 53 denotes a source side driver circuit, and 54 denotes an area where a gate side driver circuit is arranged. As shown in FIG. 13, connection electrode pads for flowing a current from an external power source at the end of the gate wiring 56 are provided in the vicinity of the end face of the substrate when performing electrolytic plating. In this embodiment, connection electrode pads corresponding to the same number of gate wirings 56 are provided. Alternatively, the gate wiring may be divided so that all the gate wirings have a conductive potential and then plated, and then divided to form individual gate wirings.
[0090]
Next, after the alignment film 62a is formed, a rubbing process is performed. Next, the substrate and the counter substrate 60 are bonded to each other with a sealing material (not shown), and a liquid crystal material 63 is injected between the substrates, followed by sealing. The counter substrate 60 is previously provided with a counter electrode 61 made of a transparent conductive film and an alignment film 62b that has been subjected to a rubbing process. Finally, an FPC (flexible printed circuit) for connecting to an external circuit is attached to the terminal electrode, and a polarizing plate and a color filter are further provided.
[0091]
The active matrix liquid crystal display device is completed through the above steps.
[0092]
Note that three types of structures (transmission type, reflection type, and transflective type) can be considered for an active matrix liquid crystal display device having TFTs. The pixel electrode is a transparent conductive film, a transmissive type with a backlight, the pixel electrode is a reflective metal film, the reflective type reflects external light, and a part of the pixel electrode is a transparent conductive film, and the other part is a reflective metal. There is a transflective type in which the film is switched as appropriate, but the present invention can be applied to any structure.
[0093]
This embodiment can be freely combined with the embodiment mode.
[0094]
[Example 3]
Various modules (active matrix type liquid crystal module, active matrix type EC module) can be completed in the driver circuit and the pixel portion formed by implementing the present invention. That is, according to the present invention, all electronic devices in which they are incorporated into the display portion can be completed.
[0095]
Such electronic devices include video cameras, digital cameras, head mounted displays (goggles type displays), car navigation systems, projectors, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones, electronic books, etc.), etc. Can be mentioned. Examples of these are shown in FIGS.
[0096]
FIG. 14A illustrates a personal computer, which includes a main body 2001, an image input portion 2002, a display portion 2003, a keyboard 2004, and the like.
[0097]
FIG. 14B shows a mobile computer, which includes a main body 2201, a camera unit 2202, an image receiving unit 2203, operation switches 2204, a display unit 2205, and the like.
[0098]
FIG. 14C shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded, and includes a main body 2401, a display portion 2402, a speaker portion 2403, a recording medium 2404, an operation switch 2405, and the like. This player uses a DVD (Digital Versatile Disc), CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet.
[0099]
FIG. 15A illustrates a portable book (electronic book), which includes a main body 3001, display portions 3002 and 3003, a storage medium 3004, operation switches 3005, an antenna 3006, and the like.
[0100]
FIG. 15B shows a display, which includes a main body 3101, a support base 3102, a display portion 3103, and the like. The present invention can complete the display portion 3103 having a diagonal of 10 to 50 inches.
[0101]
As described above, the applicable range of the present invention is so wide that electronic devices in various fields can be completed. In addition, the electronic apparatus of this example can be realized by using a configuration including any combination of the embodiment mode, the first example, and the second example.
[0102]
【The invention's effect】
According to the present invention, in a semiconductor device typified by an active matrix light-emitting display device or a liquid crystal display device, an excellent display can be realized even if the area of a pixel portion is increased and the screen size is increased. Since the resistance of the wiring of the pixel portion can be greatly reduced, the present invention can be applied to, for example, a large screen with a diagonal of 40 inches or a diagonal of 50 inches.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a process of the present invention. (Embodiment)
FIG. 2 is a cross-sectional view of a light emitting element of the present invention. (Example 1)
FIGS. 3A and 3B are top views of a light-emitting device in the manufacturing process. FIGS. (Example 1)
FIGS. 4A and 4B are top views of a manufacturing process of a light-emitting device. FIGS. (Example 1)
FIGS. 5A and 5B are top views of a manufacturing process of a light-emitting device. FIGS. (Example 1)
FIGS. 6A and 6B are top views of a manufacturing process of a light-emitting device. FIGS. (Example 1)
FIG 7 illustrates a stacked structure of a light-emitting element. (Example 1)
FIG. 8 is a schematic diagram in the case of full color using white light emission. (Example 1)
FIG. 9 is a graph showing the transmittance of a colored layer. (Example 1)
FIG. 10 is a diagram showing chromaticity coordinates. (Example 1)
11A and 11B are a cross-sectional view and a top view of an active display device. (Example 1)
FIG. 12 is a cross-sectional view of a liquid crystal display device. (Example 2)
FIG. 13 is a top view of a manufacturing process of a liquid crystal display device. (Example 2)
FIG 14 illustrates an example of an electronic device.
FIG 15 illustrates an example of an electronic device.

Claims (16)

A substrate having an insulating surface;
A first insulating film on the substrate;
A wiring embedded in the first insulating film;
A first insulating film and a second insulating film on the wiring;
A thin film transistor on the second insulating film,
The thin film transistor has a semiconductor layer, a gate insulating film, and a gate electrode,
The wiring is made of copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof,
A barrier layer is provided between the wiring and the first insulating film and between the wiring and the second insulating film, and the barrier layer is in contact with the wiring,
The semiconductor device, wherein the gate electrode of the thin film transistor is electrically connected to the wiring. A substrate having an insulating surface;
A first insulating film on the substrate;
A wiring embedded in the first insulating film;
A first insulating film and a second insulating film on the wiring;
A thin film transistor on the second insulating film,
The thin film transistor includes a semiconductor layer having a source region and a drain region, a gate insulating film, and a gate electrode,
The wiring is made of copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof,
A barrier layer is provided between the wiring and the first insulating film and between the wiring and the second insulating film, and the barrier layer is in contact with the wiring,
The semiconductor device is characterized in that the source region of the thin film transistor is electrically connected to the wiring. A substrate having an insulating surface;
A first insulating film on the substrate;
A wiring embedded in the first insulating film;
A first insulating film and a second insulating film on the wiring;
A thin film transistor on the second insulating film,
The thin film transistor includes a semiconductor layer having a source region and a drain region, a gate insulating film, and a gate electrode,
The wiring is made of copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof,
A barrier layer is provided between the wiring and the first insulating film and between the wiring and the second insulating film, and the barrier layer is in contact with the wiring,
The semiconductor device, wherein the drain region of the thin film transistor is electrically connected to the wiring. In claim 1,
The semiconductor device, wherein the wiring is a gate wiring. In claim 2,
The semiconductor device is characterized in that the wiring is a source wiring or a power supply line. A substrate having an insulating surface;
A first insulating film on the substrate;
A gate wiring embedded in the first insulating film;
A second insulating film on the first insulating film and the gate wiring;
A thin film transistor on the second insulating film,
The thin film transistor has a semiconductor layer, a gate insulating film, and a gate electrode,
The gate wiring is made of copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof.
The semiconductor device, wherein the gate electrode of the thin film transistor is electrically connected to the gate wiring. A substrate having an insulating surface;
A first insulating film on the substrate;
A power supply line embedded in the first insulating film;
The first insulating film and the second insulating film on the power supply line;
A thin film transistor on the second insulating film,
The thin film transistor includes a semiconductor layer having a source region and a drain region, a gate insulating film, and a gate electrode,
The power supply line is made of copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof.
The semiconductor device, wherein the source region of the thin film transistor is electrically connected to the power supply line. In any one of Claims 1 thru | or 7 ,
A light-emitting element formed on the substrate, in which a first electrode, a layer containing an organic compound, and a second electrode are sequentially stacked; and a sealing substrate that is bonded to the substrate and seals the light-emitting element; A semiconductor device comprising: 9. The semiconductor device according to claim 8 , wherein the layer containing an organic compound is a material that emits white light, and is combined with a color filter provided on the sealing substrate. 9. The semiconductor device according to claim 8 , wherein the layer containing an organic compound is a material that emits monochromatic light, and is combined with a color conversion layer or a colored layer provided on the sealing substrate.   11. The semiconductor device according to claim 1, wherein the semiconductor device is a display, a DVD player, an electronic game machine, or a personal computer.   The semiconductor device according to claim 1, wherein the semiconductor device is a light emitting device. In any one of claims 1 to 7, a semiconductor device wherein the semiconductor device is a liquid crystal display device. Forming a conductive etching stopper layer on the insulating surface;
Forming a first insulating film covering the etching stopper layer;
Etching the first insulating film to form an opening reaching the etching stopper layer;
Forming a seed in the opening;
Plating the seed, forming an embedded wiring covering the opening;
Performing a planarization process to planarize the upper surface of the first insulating film and the upper surface of the embedded wiring;
Forming a second insulating film containing aluminum on the first insulating film and the embedded wiring;
Forming a third insulating film on the second insulating film;
A thin film transistor having a semiconductor layer having a source region and a drain region, a gate insulating film, and a gate electrode is formed on the third insulating film,
The method for manufacturing a semiconductor device, wherein the source region, the drain region, or the gate electrode is electrically connected to the embedded wiring.   15. The method for manufacturing a semiconductor device according to claim 14, wherein the embedded wiring is a source wiring, a gate wiring, or a power supply line.   16. The method for manufacturing a semiconductor device according to claim 14, wherein the embedded wiring is copper, silver, gold, chromium, iron, nickel, platinum, or an alloy thereof.

Images