JP2002280186A - Light emitting device and method for producing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device capable of solving the problem of a conventional device wherein a first electrode is not evenly formed and a point emitting no light (called a dark spot since it is observed as a black point) is produced, and eventually a failure of horizontal short-circuiting of the first electrode and a second electrode occurs, if an insulated surface forming the first electrode is not flat and there is an uneven part or a foreign article having a thickness equivalent to or thicker than the film thickness of the first electrode. SOLUTION: The structure of this light emitting device has the first electrode formed on the insulated surface, a first insulating layer covering the end of the first electrode and having a taper rim, a second insulating layer of one or more kinds selected from silicon oxide, silicon nitride, oxidized and oxynitride silicon, an organic compound layer formed on the second insulating layer, and a second electrode formed on the organic compound layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using a light emitting element having a film containing an organic compound capable of emitting fluorescence or phosphorescence by applying an electric field (hereinafter referred to as "organic compound layer"). And a method for manufacturing the same.

[0002] In the present invention, a light-emitting element refers to an element having an organic compound layer provided between a pair of electrodes, and a light-emitting device refers to an image display device or a light-emitting device using a light-emitting element as a light-emitting element. Further, a connector such as an anisotropic conductive film (FPC: Flexible Pr.
inted Circuit) or TAB (Tape Automated Bondi)
ng) A module with a tape or TCP (Tape Carrier Package) attached, a module with a printed wiring board provided at the end of a TAB tape or TCP, or an IC (integrated circuit) using a COG (Chip On Glass) method for the light emitting element. All the modules directly mounted are also included in the light emitting device.

[0003]

2. Description of the Related Art Light-emitting elements using organic compounds having characteristics such as thinness and lightness, high-speed response, and low-voltage direct current drive as light-emitting elements are expected to be applied to next-generation flat panel displays. In particular, a display device in which light-emitting elements are arranged in a matrix is compared with a conventional liquid crystal display device.
It is considered to be superior in that the viewing angle is wide and the visibility is excellent.

The light emitting mechanism of the light emitting element is such that electrons injected from the second electrode and holes injected from the first electrode are applied to the organic compound layer by applying a voltage across the organic compound layer between the electrodes. It is said that a molecular exciton forms a molecular exciton by recombination at the center of the luminescence, and emits energy when the molecular exciton returns to the ground state. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.

[0005] As a driving method of a light emitting device formed by arranging such light emitting elements in a matrix, both passive matrix driving (simple matrix type) and active matrix driving are possible. However, when the pixel density increases, it is considered that active matrix driving in which a switch is provided for each pixel (or one dot) is advantageous because it can be driven at a low voltage.

An active matrix light emitting device having a light emitting element has an element structure as shown in FIG. 2, in which a thin film transistor (hereinafter referred to as TFT) 202 is formed on a substrate 201, and Then, an interlayer insulating film 203 is formed. On the interlayer insulating film 203, a first electrically connected TFT 202 via a wiring 204 is formed.
Electrode (anode) 205 is formed. First electrode 205
A transparent conductive material having a large work function is suitable as a material for forming the layer, and typically, ITO (indium tin oxy) is used.
des) is used.

On the first electrode 205, the organic compound layer 2
06 is formed. Note that in this specification, all layers provided between the first electrode and the second electrode are referred to as organic compound layers for convenience. The organic compound layer 206 specifically includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, and the like. Basically, the light emitting element has a structure in which a first electrode / a light emitting layer / a second electrode are sequentially stacked. In addition to this structure, a first electrode / a hole injection layer / a light emitting layer / It may have a structure in which a second electrode or a first electrode / a hole injection layer / a light emitting layer / an electron transport layer / a second electrode are stacked in this order.

After forming the organic compound layer 206, the second
The light emitting element 209 is formed by forming the electrode 207 of FIG. As the second electrode, a metal having a small work function (typically, a metal belonging to Group 1 or 2 of the periodic table)
Is often used.

A first insulating layer 208 made of an organic resin material is formed so as to cover an end of the first electrode, and to prevent a short circuit between the second electrode and the first electrode at this portion. Are formed. Note that FIG. 2 shows only light-emitting elements formed in one pixel; however, in practice, a plurality of these elements are formed in a pixel portion to form an active matrix light-emitting device.

[0010]

However, since the organic compound layer is formed with a thickness of about 50 to 150 nm,
If the surface of the first electrode (anode) is not flat and has fine irregularities, there is a problem that the organic compound layer is not formed with a uniform thickness.

If the insulating surface on which the first electrode is formed is not flat and there are irregularities or foreign matters having a thickness of about the thickness of the first electrode or more, the electrode is not formed uniformly first. There is a problem that the organic compound layer is not uniformly formed due to the unevenness.

As a result, when the second electrode (cathode) is formed on the organic compound layer, a point that does not emit light (referred to as a dark spot because it is observed as a black point) occurs in one pixel, and consequently the first electrode. This causes a defect that the electrode and the second electrode are short-circuited vertically.

The organic compound layer has the property of being easily degraded by oxygen or moisture, but the material used as the interlayer insulating film is often an organic resin material such as polyimide, polyamide, or acrylic. There is a problem that a light emitting element is deteriorated by a gas such as oxygen generated from an interlayer insulating film formed by using the method.

As the second electrode material of the light emitting element, an alkali metal or alkaline earth metal material such as Li or Mg, which is a mobile ion for the semiconductor forming the TFT and is a bad impurity, is used. Therefore, in the active matrix type light emitting device, the second electrode material is TF
It is necessary not to diffuse to the T side.

The present invention has been made in view of the above problems, and has as its object to improve the reliability of a light emitting device including a light emitting element using an organic compound.

[0016]

In order to solve the above problems,
The structure of the light emitting device of the present invention includes a first electrode formed on an insulating surface, a first insulating layer having a tapered edge covering an end of the first electrode, a first electrode, and the first electrode. A second insulating layer formed on the first insulating layer and formed of one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride; and an organic compound layer formed on the second insulating layer. ,
A second electrode formed on the organic compound layer.

In addition to the above structure, a thin film transistor having a source region and a drain region, an interlayer insulating film on the source region and the drain region, an opening formed in the interlayer insulating film, and a drain electrode connected to the drain region When,
A first layer formed on the interlayer insulating film and connected to the drain electrode;
Forming an opening on the first electrode and the first electrode; and
A first electrode covering an end of the first electrode and having a tapered edge;
A second insulating layer formed on the first electrode and the first insulating layer, the second insulating layer being formed of one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride; An organic compound layer formed on the insulating layer and a second electrode formed on the organic compound layer are provided. The second insulating layer may be formed using a material containing carbon as a main component. Typically, diamond-like carbon can be applied.

The second insulating layer has a thickness of 1 to 10 nm, preferably 2 to 10 nm.
With a thickness of about 3 nm, a tunnel current can flow between the first electrode and the organic resin layer. By providing the second insulating layer, fine irregularities on the surface of the first electrode (anode) can be planarized, and the organic compound layer can be formed uniformly. Even when the first interlayer insulating film or the second interlayer insulating film has unevenness or foreign matter of several tens to several hundreds of nm, a dark spot or a first electrode can be formed by forming the second insulating layer. And the second electrode can be prevented from being short-circuited and the light-emitting element from being turned off.

The insulating surface or the interlayer insulating film is formed of polyimide, acrylic, silicon nitride, or silicon oxynitride.

In order to solve the above problems, a method for manufacturing a light emitting device according to the present invention comprises forming a first electrode on an insulating surface, covering an end of the first electrode, and having a tapered edge. Forming one insulating layer, forming a second insulating layer of one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride on the first electrode and the first insulating layer; In this method, an organic compound layer is formed over a second insulating layer, and a second electrode is formed over the organic compound layer.

In another method, an interlayer insulating film is formed on the source and drain regions of a thin film transistor having a source region and a drain region, and an opening reaching the drain region is formed in the interlayer insulating film. Forming a drain electrode, forming a first electrode connected to the drain electrode on the interlayer insulating film, and forming a first electrode connected to the drain electrode;
Forming an insulating layer covering the first electrode, forming an opening on the first electrode to provide a first insulating layer, and forming silicon oxide and silicon nitride on the first electrode and the first insulating layer. And a method of forming a second insulating layer made of one or more kinds selected from silicon oxynitride, and forming a second electrode on the organic compound layer.

The second insulating layer may be formed of a material containing carbon as a main component. Typically, diamond-like carbon (hereinafter referred to as DLC) can be used. The second insulating layer is formed with a thickness of 1 to 10 nm, preferably 2 to 3 nm. In order to form a film with such a small thickness and uniformity over the first electrode and the first insulating layer, it is preferable to form the film by a plasma CVD method or a sputtering method.

The light-emitting element of the present invention includes light emission in one of a singlet excited state and a triplet excited state, or both.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a method for manufacturing a pixel portion of a light emitting device and its structure will be described with reference to FIGS.

In FIG. 1A, TF is placed on a substrate 100.
T101 is formed. The TFT shown here is a TFT for controlling a current flowing to the light emitting element, and is referred to as a current control TFT 101 in this specification. This T
In the semiconductor film of the FT 101, a source region 102 and a drain region 103 to which an impurity of one conductivity type is added are formed.

An interlayer insulating film 104 is formed on the current controlling TFT 101. The interlayer insulating film 104 is formed using an organic resin material such as polyimide, acrylic, or polyimide amide. These materials can be planarized by applying them with a spinner and then heating and baking or polymerizing them. Further, the organic resin material generally has a low dielectric constant, so that the parasitic capacitance can be reduced.

Next, a second interlayer insulating film 105 is formed on the first interlayer insulating film 104 so that degassing from the interlayer insulating film 104 does not adversely affect the light emitting element. The second interlayer insulating film 105 may be formed using an inorganic insulating film, typically, a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a stacked film obtained by combining them. 20-200Pa, substrate temperature 30
It is formed by discharging at a high frequency (13.56 MHz) at a power density of 0.1 to 1.0 W / cm ² at a temperature of 0 to 400 ° C. Alternatively, a plasma treatment may be performed on the surface of the interlayer insulating film to form a cured film containing one or more kinds of gas elements selected from hydrogen, nitrogen, carbon halide, hydrogen fluoride, and a rare gas.

Thereafter, a resist mask having a desired pattern is formed, a contact hole reaching the drain region of the current controlling TFT 101 is formed, and a wiring 106 is formed. As a wiring material, a conductive metal film such as Al or T
In addition to i, a film may be formed by a sputtering method or a vacuum evaporation method using these alloy materials, and then patterned into a desired shape.

Next, the first electrode 107 of the light emitting element is
The transparent conductive film is formed using indium tin oxide (ITO) or a mixture of indium oxide and zinc oxide (ZnO) at 2 to 20%.

As will be described later, ITO is used when the second insulating layer is formed of one or more selected from silicon oxide, silicon nitride, and silicon oxynitride. Also,
In the case where the second insulating layer is formed by DLC, the second insulating layer can be formed with good adhesion by using ZnO or a compound of ZnO and ITO.

Subsequently, as shown in FIG. 1B, the first conductive film 107 is formed by etching the transparent conductive film. Thereafter, an organic resin film made of polyimide, acrylic, or polyimide amide is formed on the entire surface. These can be made of a thermosetting material that is cured by heating or a photosensitive material that is cured by irradiating ultraviolet rays. When a thermosetting material is used, a resist mask is formed thereafter, and the first insulating layer 109 having an opening over the first electrode is formed by dry etching. In the case of using a photosensitive material, the first insulating layer 109 having an opening is formed over the first electrode by performing exposure and development using a photomask. In any case, the first insulating layer 109
Is formed so as to cover the end of the first electrode 107 and have a tapered edge. By forming the edge in a tapered shape, coverage with a second insulating layer, an organic compound layer, or the like to be formed later can be improved.

Next, the surface of the first electrode 108 is wiped with a cleaning liquid using a PVA (polyvinyl alcohol) -based porous material to flatten the surface of the first electrode 108 and remove dust and the like. Note that in this specification, a process of wiping the surface of the first electrode with a PVA (polyvinyl alcohol) -based porous body and performing flattening and removing dust is referred to as wiping.

Thereafter, at 200 to 300 ° C., preferably 2
By heating at 50 ° C., moisture contained in the first insulating layer 109 is released. Accordingly, a change in volume and dehydration of the first insulating layer after the light-emitting element is completed can be prevented, and initial deterioration and long-term stability of the light-emitting device can be secured.

After wiping the surface of the first electrode, the second electrode
Is formed. The second insulating layer is formed using one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride, or an insulating material mainly containing carbon. Preferably, a silicon oxynitride film formed using a mixed gas of SiH ₄ and N ₂ O by a plasma CVD method is used. The ratio of oxygen (O) and nitrogen (N) contained in the silicon oxynitride film is set so that (O / (N + O)) = 0.8 to 1.2. With such a composition ratio,
It enhances light transmittance in a short wavelength region and enhances blocking properties of alkali metals and alkaline earth metals.

Other effects similar to those of the second insulating layer can be obtained by an insulating film containing carbon as a main component. A typical example is DLC.

Since the second insulating layer 112 is formed so as to be interposed between the first insulating film 108 and an organic compound layer 113 to be formed later, the second insulating layer 112 needs to be thick enough to allow a tunnel current to flow. . Therefore, the thickness is 1-10 nm,
Preferably, it is formed as 2-3 nm.

The organic compound layer 113 includes a hole transporting layer, a hole blocking layer, an electron transporting layer,
It is formed by laminating a plurality of layers such as an electron injection layer and a buffer layer in combination. This organic compound layer 113 is formed with a thickness of about 10 to 150 nm.

The second electrode 114 has an organic compound layer 113
After the film formation, it is formed by an evaporation method. As a material to be the second electrode 114, in addition to the MgAg alloy and the AlLi alloy,
A film in which an element belonging to Group 1 or 2 of the periodic table and aluminum are formed by a co-evaporation method can also be used.
Note that the thickness of the second electrode 114 is preferably about 80 to 200 nm.

As described above, 1 to 10 n is formed on the first electrode.
By providing a second insulating layer having a thickness of about m, preferably about 2 to 3 nm through which a tunnel current can flow, fine irregularities on the surface of the first electrode (anode) are flattened and the organic compound layer is uniformly formed. Can be formed. Even when the first interlayer insulating film 104 or the second interlayer insulating film 105 has irregularities or foreign matter of several tens to several hundreds of nm, a dark spot or a first spot is formed by forming the second insulating layer. And the second electrode can be prevented from being short-circuited and the light emitting element from turning off.

By providing the second insulating layer 112,
Degassing from the first insulating layer 109 formed of an organic resin material such as polyimide, polyamide, or acrylic can be prevented, and the organic compound layer 113 can be prevented from being deteriorated. In addition, it is possible to prevent Li and Mg, which are elements constituting the second electrode 114, from diffusing to the current control TFT 101 side.

[0041]

[Embodiment 1] In this embodiment, a light emitting element manufactured by using the present invention will be described. Here, an example of a method for simultaneously manufacturing a pixel portion having the light-emitting element of the present invention over the same substrate and a TFT (n-channel TFT and p-channel TFT) of a driver circuit provided around the pixel portion is described. This will be described with reference to FIGS.

First, as shown in FIG. 3A, a substrate 900 made of glass such as barium borosilicate glass represented by Corning # 7059 glass or # 1737 glass, or aluminoborosilicate glass is used. Note that the substrate 900 is not limited as long as it has a light-transmitting property, and a quartz substrate may be used. Further, a plastic substrate having heat resistance that can withstand the processing temperature of the present embodiment may be used.

Next, a base insulating film 901 made of an insulating film such as a silicon oxide film, a silicon nitride film or a silicon oxynitride film is formed on the substrate 900. Although a two-layer structure is used as the base insulating film 901 in this embodiment, 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 of the base insulating film 901, a silicon oxynitride film 901a formed using SiH ₄ , NH ₃ , and N ₂ O as a reaction gas by a plasma CVD method is 10 to 200 nm (preferably 50 to 100 nm). Form. In this embodiment, a 50 nm-thick silicon oxynitride film 901a (composition ratio Si = 3
2%, O = 27%, N = 24%, H = 17%). Next, as the second layer of the base insulating film 901, a silicon oxynitride film 901 b formed using SiH ₄ and N ₂ O as a reaction gas by plasma CVD is used to form a 50 to 20 layer.
The layer is formed to a thickness of 0 nm (preferably 100 to 150 nm). In this embodiment, a 100 nm-thick silicon oxynitride film 901b (composition ratio: Si = 32%, O = 59%, N = 7)
%, H = 2%).

Next, the semiconductor layer 9 is formed on the base insulating film 901.
02 to 905 are formed. The semiconductor layers 902 to 905 are
After forming a semiconductor film having an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, or the like), a known crystallization treatment (laser crystallization method, thermal crystallization method, nickel, or the like) The crystalline semiconductor film obtained by performing the thermal crystallization method using a catalyst described above is patterned into a desired shape and formed. These semiconductor layers 902 to 90
5 is formed to have a thickness of 25 to 80 nm (preferably 30 to 60 nm). Without limitation on the material of the crystalline semiconductor film, preferably silicon (silicon) or silicon germanium _{(Si X Ge 1-X (} X = 0.0001~0.0
2)) It is good to form with an alloy etc. In this embodiment, after a 55 nm amorphous silicon film is formed by a plasma CVD method, a solution containing nickel is held on the amorphous silicon film. Dehydrogenation of this amorphous silicon film (500 ° C, 1 hour)
Is performed, thermal crystallization (550 ° C., 4 hours) is performed, and a laser annealing process for improving crystallization is performed to form a crystalline silicon film. Then, semiconductor layers 902 to 905 are formed by patterning the crystalline silicon film using a photolithography method.

After forming the semiconductor layers 902 to 905, the semiconductor layers 90 to 905 are controlled in order to control the threshold value of the TFT.
2 to 905 may be doped with a trace amount of an impurity element (boron or phosphorus).

When a crystalline semiconductor film is formed by a laser crystallization method, a pulse oscillation type or continuous emission type excimer laser, a YAG laser, or a YVO ₄ laser can be used. In the case of using these lasers, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly condensed by an optical system and irradiated on a semiconductor film. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is set to 300 Hz, and the laser energy density is set to 100 to 4.
(Typically ^{200~300mJ / cm 2) 00mJ / cm} 2 to.
When a YAG laser is used, the second harmonic is used to set the pulse oscillation frequency to 30 to 300 kHz and the laser energy density to 300 to 600 mJ / cm ² (typically 350 to 500 mJ / cm ² ). And width 100
The entire surface of the substrate is irradiated with a laser beam condensed linearly at a wavelength of １０００1000 μm, for example, 400 μm, and the superposition rate (overlap rate) of the linear laser light at this time is 50-90.
% May be used.

Next, a gate insulating film 906 covering the semiconductor layers 902 to 905 is formed. The gate insulating film 906 is formed by a plasma CVD method or a sputtering method and has a thickness of 40 to
The insulating film containing silicon is formed to have a thickness of 150 nm. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N =
7%, H = 2%). Of course, 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.

When a silicon oxide film is used, TEOS (Tetraethyl Ortho Silicon Cathode) is formed by a plasma CVD method.
e) and O ₂ were mixed, the reaction pressure was 40 Pa, and the substrate temperature was 30.
It can be formed by discharging at a high-frequency (13.56 MHz) power density of 0.5 to 0.8 W / cm ² at 0 to 400 ° C. The silicon oxide film thus produced is
Good characteristics as a gate insulating film can be obtained by thermal annealing at 00 to 500 ° C.

Then, a heat-resistant conductive layer 907 for forming a gate electrode on the gate insulating film 906 is
It is formed with a thickness of 0 nm (preferably 250 to 350 nm). The heat-resistant conductive layer 907 may be formed as a single layer, or may have a stacked structure including a plurality of layers such as two layers or three layers as needed. Ta, Ti,
An element selected from W, an alloy containing the above element, or an alloy film combining the above elements is included. These heat-resistant conductive layers are formed by a sputtering method or a CVD method, and it is preferable to reduce the impurity concentration to reduce the resistance.
It is good to be 0 ppm or less. In this embodiment, the W film is 300 n
It is formed with a thickness of m. The W film is formed by sputtering using W as a target.

On the other hand, when a Ta film is used for the heat-resistant conductive layer 907, it can be similarly formed by a sputtering method. The Ta film uses Ar as a sputtering gas. Also, if an appropriate amount of Xe or Kr is added to the gas during sputtering,
The internal stress of the film to be formed can be relaxed to prevent the film from peeling. Although not shown, the heat-resistant conductive layer 907
It is effective to form a silicon film doped with phosphorus (P) with a thickness of about 2 to 20 nm under the layer. Thereby, the adhesion of the conductive film formed thereon is improved and oxidation is prevented, and at the same time, the alkali metal element present in a trace amount in the heat-resistant conductive layers 907 and 908 has the first shape. 906 can be prevented. In any case, the heat-resistant conductive layer 907 has a resistivity of 10 to 50 μm.
It is preferable to set it in the range of Ωcm.

In this embodiment, a TaN film is formed on the first conductive layer (first conductive film 907), and a W film is formed on the second conductive layer (second conductive film 908) (FIG. 3).
(A)).

Next, a resist mask 909 is formed by using a photolithography technique. And
A first etching process is performed. The first etching process is performed under the first etching condition and the second etching condition.

[0053] using an ICP etching device in the present embodiment, using Cl ₂ and CF ₄ O ₂ as etching gas, the gas flow rate is set to 25/25/10, 3.2 W / cm ² at a pressure of 1Pa Of RF (13.56 MHz) power to form plasma. RF (13.56 MHz) power of 224 mW / cm ² is also applied to the substrate side (sample stage), whereby a substantially negative self-bias voltage is applied.
The W film is etched under the first etching condition. Subsequently, without removing the resist mask, the etching conditions were changed to the second etching condition, and CF ₄ and C
Using l ₂ , each gas flow ratio is set to 30/30 (SCC
M), and RF (13.56 MHz) power is applied at a pressure of 1 Pa to form plasma. Substrate side (sample stage)
Also, a 20 W RF (13.56 MHz) power is applied, and a substantially negative self-bias voltage is applied.

The conductive layers 910 to 913 having the first tapered shape are formed by the first etching process. The angle of the tapered portion of the conductive layers 910 to 913 is 15 to 30 °
It is formed so that In order to perform etching without leaving a residue, over-etching is performed to increase the etching time at a rate of about 10 to 20%. Silicon oxynitride film (gate insulating film 9) for W film
06) is 2-4 (typically 3),
By the over-etching process, the exposed surface of the silicon oxynitride film is etched by about 20 to 50 nm (FIG. 3).
(B)).

Then, a first doping process is performed to add an impurity element of one conductivity type to the semiconductor layer. Here, a step of adding an impurity element for imparting n-type without removing the resist mask 909 is performed. Semiconductor layers 902 to 90
5, a conductive film 910 having a first tapered shape.
Impurities are added in a self-aligning manner using 913 as a mask to form first n-type impurity regions 914 to 917. An element belonging to group 15 of the group 15, typically phosphorus (P) or arsenic (As) is used as the impurity element imparting n-type conductivity. Here, phosphorus (P) is used, and the first n-type impurity is doped by ion doping. In the regions 914 to 917, 1 × 10 ²⁰ to 1 × 10 ²¹
An impurity element imparting n-type is added in a concentration range of / cm ³ (FIG. 3B).

Next, a second etching process is performed without removing the resist mask. The second etching is performed under the third etching condition and the fourth etching condition. The second etching process is also performed by an ICP etching apparatus in the same manner as the first etching process, using CF ₄ and Cl ₂ as etching gases, adjusting the respective gas flow rates to 30/30 (SCCM), and applying RF at a pressure of 1 Pa. (13.
(56 MHz) power is supplied to form plasma. 20W RF (13.56 MH) on the substrate side (sample stage)
z) Turn on the power and apply a substantially negative self-bias voltage. Under the third etching condition, the W film and the TaN film are etched to the same extent as the conductive films 918 to 918.
921 is formed (FIG. 3C).

Thereafter, the mask made of resist is used as it is, and the etching condition is changed to the fourth etching condition, a mixed gas of CF ₄ , Cl ₂ and O ₂ is used as an etching gas, and RF power (13.56 MHz) is applied at a pressure of 1 Pa. ) Power is applied to form plasma. A 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. The W film is etched under the fourth etching conditions to form the second shape conductive films 922-9.
25 are formed (FIG. 3D).

Next, a second doping step (addition of an n-type impurity element to the semiconductor layer through the first conductive films 922a to 925a of the second shape) is performed to form the first n-type impurity regions 914 to 917. And second n-type impurity regions 926 to 929 are formed on the side of the channel formation region in contact with. The second n
The impurity concentration in the type impurity region is 1 × 10 ¹⁶ to 1 ×
It should be 10 ¹⁹ / cm ³ . In the second doping step, the second-layer conductive films 922a to 922a of the first layer are formed.
The condition is such that the n-type impurity element is added to the semiconductor layer even through the tapered portion 925a, and in this specification, the first-layer second-shape conductive films 922a to 925 are used.
The second n-type impurity region overlapping with a is Lov (ov is overlapp
region, attached in the meaning of ed) Region, first layer conductive film 9 of second shape
A second n-type impurity region that does not overlap with any of 22a to 925a is referred to as Loff (off means offset) (FIG. 4A).

As shown in FIG. 4B, impurity regions 932 (932a, 932a, 932) of a conductivity type opposite to one conductivity type are formed in semiconductor layers 902, 905, which will be active layers of the p-channel TFT later.
32b) and 933 (9323a, 933b). Also in this case, an impurity element imparting p-type is added using the first shape conductive layers 910 and 913 as a mask to form an impurity region in a self-aligned manner. At this time, the semiconductor layers 903 and 904 which will be active layers of the subsequent n-channel TFT are
Masks 930 and 931 made of resist are formed and the entire surface is covered. P-type impurity region 93 formed here
_2, 933 are formed by ion doping using diborane (B ₂ H ₆ ), and the concentration of the impurity element imparting p-type in the p-type impurity regions 932, 933 is 2 × 10 ²⁰ to 2 × 10 ²¹ /. c
made to be m ^3.

The p-type impurity regions 932 and 933 specifically contain an impurity element imparting n-type, and the concentration of the impurity element imparting p-type in these impurity regions 932 and 933 is n-type. Of the concentration of the impurity element that imparts
Since the p-type impurity region functions as the source region and the drain region of the p-channel TFT by being added so as to be 5 to 3 times, there is no problem.

Thereafter, as shown in FIG. 4C, a first interlayer insulating film 934 is formed on the conductive layers 922 to 925 having the second shape and the gate insulating film 906. The first interlayer insulating film 934 may be formed using a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a stacked film obtained by combining these. In any case, the first interlayer insulating film 934 is formed from an inorganic insulating material. The thickness of the first interlayer insulating film 934 is 100 to 200 nm. In the case where a silicon oxide film is used as the first interlayer insulating film 934, TEOS and O ₂ are mixed by a plasma CVD method, the reaction pressure is 40 Pa, the substrate temperature is 300 to 400 ° C., and the high frequency (1
(3.56 MHz) can be formed by discharging at a power density of 0.5 to 0.8 W / cm ² . Also, the first interlayer insulating film 92
When a silicon oxynitride film is used as 8, a silicon oxynitride film formed from SiH ₄ , N ₂ O, and NH ₃ by a plasma CVD method, or a silicon oxynitride film formed from SiH ₄ and N ₂ O is used. It may be formed. The production conditions in this case are a reaction pressure of 20 to 200 Pa and a substrate temperature of 300 to 200 Pa.
400 ℃, high frequency (60MHz) power density 0.1 ~
It can be formed at 1.0 W / cm ² . Alternatively, as the first interlayer insulating film 934, a hydrogenated silicon oxynitride film formed using SiH ₄ , N ₂ O, and H ₂ may be used. Similarly, the silicon nitride film is made of SiH ₄ , NH ₃ by a plasma CVD method.
It is possible to produce from.

Then, a step of activating the impurity elements imparting n-type or p-type added at the respective concentrations is performed. This step is performed by a thermal annealing method using a furnace annealing furnace. In addition, a laser annealing method or a rapid thermal annealing method (RTA method) can be applied. In the thermal annealing method, the oxygen concentration is 400 to 70 ppm in a nitrogen atmosphere of 1 ppm or less, preferably 0.1 ppm or less.
0 ° C., typically at 500-600 ° C.,
In this embodiment, the heat treatment is performed at 550 ° C. for 4 hours. When a plastic substrate having a low heat-resistant temperature is used as the substrate 900, a laser annealing method is preferably applied.

In this heat treatment step, the catalyst element (nickel) used in the step of crystallizing the semiconductor layer contains a high concentration of an element belonging to Group 15 of the periodic table having a gettering action (phosphorus in this embodiment). By moving (gettering) to the added first n-type impurity region, the concentration of the catalyst element in the channel formation region can be reduced.

Subsequent to the activation step, the atmosphere gas is changed and the atmosphere gas is changed to 300 to 100% in an atmosphere containing 3 to 100% hydrogen.
A heat treatment is performed at 450 ° C. for 1 to 12 hours to hydrogenate the semiconductor layer. This step is to terminate dangling bonds of 10 ¹⁶ to 10 ¹⁸ / cm ^{3 in} the semiconductor layer by thermally excited hydrogen. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed. In any case, the semiconductor layer 9
It is preferable that the defect density in the range of 02 to 905 be 10 ¹⁶ / cm ³ or less.
% May be provided.

Then, a second interlayer insulating film 935 made of an organic insulating material is formed with an average thickness of 1.0 to 2.0 μm. As organic resin materials, polyimide, acrylic,
Polyamide, polyimide amide, BCB (benzocyclobutene) and the like can be used. For example, in the case of using a polyimide of a type that is thermally polymerized after being applied to a substrate, it is formed by firing at 300 ° C. in a clean oven.
In the case of using acrylic, a two-component type is used, and after mixing the main material and the curing agent, the whole surface is applied using a spinner and then pre-heated at 80 ° C. for 60 seconds on a hot plate. Then, it can be formed by firing in a clean oven at 250 ° C. for 60 minutes.

As described above, by forming the second interlayer insulating film 935 from an organic insulating material, the surface can be satisfactorily planarized. In addition, since organic resin materials generally have a low dielectric constant, parasitic capacitance can be reduced. However, since it is hygroscopic and is not suitable as a protective film, it may be used in combination with a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or the like formed as the first interlayer insulating film 934 as in this embodiment. .

Meanwhile, the second interlayer insulating film 935 formed using an organic insulating material may generate moisture and gas. It is known that a light emitting element is easily deteriorated by moisture or gas (oxygen). The heat generated when a light emitting device formed using an organic resin insulating film as an interlayer insulating film is actually used generates moisture and gas from the organic resin insulating film, and the light emitting element is likely to deteriorate. It is possible. Therefore, an insulating film 936 is formed over the second interlayer insulating film 935 formed using an organic insulating material.

Note that the insulating film 936 is a silicon oxide film,
It is formed using a silicon oxynitride film, a silicon nitride film, or the like. Note that the insulating film 936 formed here may be formed by a sputtering method or a plasma CVD method. Alternatively, the insulating film 936 may be formed after forming the contact hole.

Thereafter, a resist mask having a predetermined pattern is formed, and a contact hole formed in each semiconductor layer and reaching an impurity region serving as a source region or a drain region is formed. The contact hole is formed by a dry etching method. In this case, CF ₄ ,
First, the insulating film 936 is etched using a mixed gas of O ₂ , then the second interlayer insulating film 935 made of an organic resin material is etched using a mixed gas of CF ₄ , O ₂ , and He. Is changed to CF ₄ and O ₂ , and the first interlayer insulating film 934 is etched. Further, in order to increase the selectivity with respect to the semiconductor layer, a contact hole can be formed by switching the etching gas to CHF ₃ and etching the gate insulating film 906.

Then, a conductive metal film is formed by a sputtering method or a vacuum evaporation method, patterned by a mask, and then etched to form wirings 937 to 943.
Although not shown, in the present embodiment, this wiring is formed of a 50 nm-thick Ti film and a 500 nm-thick alloy film (A
1 and an alloy film of Ti).

Next, a transparent conductive film is further formed on the transparent conductive film.
The first electrode 944 is formed with a thickness of 20 nm and etched (FIG. 5A). In this embodiment, indium tin oxide (I) is used as a transparent electrode.
TO) film or indium oxide with 2-20% zinc oxide (Z
A transparent conductive film mixed with nO) is used.

The first electrode 944 is formed so as to be in contact with and overlap with the drain wiring 943, so that an electrical connection is formed with the drain region of the current controlling TFT (FIG. 5A). Here, 180 with respect to the first electrode 944
The heat treatment may be performed at -350 ° C.

Next, as shown in FIG. 5B, an insulating film 945 made of an organic resin material is formed over the first electrode 944. Here, a processing room (clean room) may be moved to form a light-emitting element. An extremely thin film having an antistatic effect (hereinafter, referred to as an antistatic film) 946 is formed over the insulating film 945 made of an organic resin material so that the TFT substrate is not contaminated with dust in the air or broken. The antistatic film 946 is formed from a material that can be removed by washing with water (FIG. 5C).

When the TFT substrate is carried into a processing room (clean room) for forming a light emitting element, an antistatic film 946 is formed.
Is removed by washing with water to form an insulating film 9 made of an organic resin material.
45 is etched to form a first insulating layer 947 having an opening at a position corresponding to the first electrode 944.
In this embodiment, the first insulating layer 947 is formed using a resist. In the present embodiment, the thickness of the first insulating layer 947 is set to about 1 μm, and a region covering a portion where the wiring and the first electrode are in contact is formed to have a tapered shape (FIG. 6).
(A)).

In this embodiment, a film made of a resist is used as the first insulating layer 947. However, in some cases, polyimide, polyamide, acryl, BC
B (benzocyclobutene), a silicon oxide film, or the like can also be used. The first insulating layer 947 may be an organic substance or an inorganic substance as long as the substance has an insulating property. However, in the case where the first insulating layer 947 is formed using photosensitive acrylic,
180-350 after etching the photosensitive acrylic film
It is preferable to carry out the heat treatment at a temperature of ° C. In the case of using a non-photosensitive acrylic film, it is preferable to perform heat treatment at 180 to 350 ° C. and then perform etching to form a first insulating layer.

Next, the surface of the first electrode 944 is subjected to a wiping treatment. Note that in this embodiment, the surface of the first electrode 944 is flattened and dust attached to the surface is removed by wiping the surface of the first electrode 944 using Berglin (manufactured by Ozu Sangyo). Pure water was used as the cleaning liquid for the wiping, and the rotation speed of the shaft around which Berglin was wound was 10
The pressure is set to 0 to 300 rpm, and the pushing value is set to 0.1 to 1.0 mm (FIG. 6A).

Next, a second insulating layer 948 is formed to cover the first insulating layer 947 and the first electrode 944. The second insulating layer 948 is made of SiH ₄ , N ₂ O by a plasma CVD method.
1. A silicon oxynitride film formed using a mixed gas of
It is formed to a thickness of 5 nm.

Next, an organic compound layer 949 and a second electrode 950 are formed over the second insulating layer 948 by an evaporation method.
In this embodiment, Mg is used as the second electrode of the light emitting element.
Although an Ag electrode is used, other known materials may be used.
Note that the organic compound layer 949 is formed by combining and stacking a plurality of layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a buffer layer in addition to the light-emitting layer. The structure of the organic compound layer used in the present embodiment will be described in detail below.

In this embodiment, copper phthalocyanine is used as the hole injection layer, and α-NPD is used as the hole transport layer.
Are formed by a vapor deposition method.

Next, a light emitting layer is formed. In this embodiment, an organic compound layer which emits different light is formed by using different materials for the light emitting layer. In the present embodiment,
An organic compound layer that emits red, green, and blue light is formed. In addition, since a vapor deposition method is used as a film formation method, a light emitting layer can be formed using a different material for each pixel by using a metal mask at the time of film formation.

[0081] The light-emitting layer that develops color to red, DC to Alq ₃
It is formed using a material doped with M. Other
N, N'-salicyltitane-1,6-hexaneseaminato) sink (II) (Zn
(Salhn)) is the Eu complex (1,10-phenanthroline) tris
(1,3-diphenyl-fluoro-1,3-diionato) europium (III) (Eu
A material doped with (DBM) ₃ (Phen) or the like can be used, but other known materials can also be used.

The light emitting layer that emits green light can be formed by co-evaporation of CBP and Ir (ppy) ₃ . At this time, it is preferable that the hole blocking layer is laminated using BCP. In addition, aluminum quinolinolato complex (Alq ₃ ) and benzoquinolinolato beryllium complex (BeBq) can be used. Further, quinolinato aluminum complex (Alq ₃ ) using a material such as coumarin 6 or quinacridone as a dopant is also possible, but other known materials can also be used.

Further, the light-emitting layer that emits blue light is composed of DPVBi, a distyryl derivative, and N, N'-diisalylicitidine-1,6-hexanesiaminato) ink (II), which is a zinc complex having an azomethine compound as a ligand. ) (Zn (salhn)) and 4,4'-bis
(2,2-Diphenyl-phenyl) -diphenyl (DPVBi) doped with perylene may be used, but other known materials may be used.

Next, an electron transport layer is formed. Note that a material such as a 1,3,4-oxadiazole derivative or a 1,2,4-triazole derivative (TAZ) can be used for the electron transporting layer.
3 by evaporation using triazole derivative (TAZ)
It is formed with a film thickness of 0 to 60 nm.

As described above, an organic compound layer having a laminated structure is formed. The thickness of the organic compound layer 950 in this embodiment is 10 to 400 nm (typically 60 to 1 nm).
50 nm), and the thickness of the second electrode 951 is 80 to 200 nm.
(Typically 100 to 150 nm).

After the formation of the organic compound layer, the second electrode 951 of the light emitting element is formed by an evaporation method. In this embodiment, the conductive film serving as the second electrode of the light emitting element is made of MgA.
Although g is used, an Al-Li alloy film (an alloy film of aluminum and lithium) or a film formed by co-evaporation of aluminum with an element belonging to Group 1 or 2 of the periodic table may be used. It is possible.

Thus, a light emitting device having a structure as shown in FIG. 6B is completed. Note that a portion 954 stacked with the first electrode 947, the organic compound layer 950, and the second electrode 951 is used.
Is called a light emitting element.

A p-channel TFT 1000 and an n-channel TFT 1001 are TFTs of a driving circuit,
S is formed. The switching TFT 1002 and the current control TFT 1003 are TFTs in a pixel portion, and the TFT in the driver circuit and the TFT in the pixel portion can be formed over the same substrate.

In the case of a light emitting device using a light emitting element,
The voltage of the power supply of the drive circuit is about 5-6V, and the maximum is 10V
Since the degree is sufficient, deterioration due to hot electrons in the TFT does not cause much problem. Thus, the substrate 1
A light emitting device that emits light toward the 00 side can be completed.

[Example 2] In Example 1, the first electrode was made of a MgAg or Al-Li alloy film, or a film formed by co-evaporation of aluminum with an element belonging to Group 1 or 2 of the periodic table and aluminum. By using a transparent conductive film material as the second electrode, a light-emitting device that emits light to the side opposite to the substrate 100 can be completed.

[Embodiment 3] In accordance with Embodiment 1, up to the second interlayer insulating film 935 is formed. Next, a method for modifying the surface of the second interlayer insulating film 935 by performing plasma treatment on the second interlayer insulating film instead of forming the insulating film 936 in Embodiment 1 will be described with reference to FIG.

The second interlayer insulating film 935 is formed of hydrogen, nitrogen, hydrocarbon, carbon halide, hydrogen fluoride, or a rare gas (A
r, He, Ne, etc.) to form the second interlayer insulating film 9 by performing a plasma treatment in one or more kinds of gases.
The second interlayer insulating film 9 is formed by forming a new coating on the surface of the second 35 or changing the type of functional group present on the surface.
35 surface modifications can be performed. On the surface of the second interlayer insulating film 935, as shown in FIG.
5B is formed. In this specification, this film is referred to as a cured film 935B. This can prevent gas and moisture from being released from the organic resin film.

Furthermore, since the first electrode (ITO) is formed after the surface modification is performed as in the present embodiment, heat treatment is not performed in a state where materials having different coefficients of thermal expansion are in direct contact with each other. . Therefore, it is possible to prevent the occurrence of cracks (cracks) and the like in the ITO, and it is also possible to prevent deterioration of the light emitting element. Note that the plasma treatment of the second interlayer insulating film 935 may be performed before or after forming the contact hole.

The cured film 935B is formed by depositing hydrogen, nitrogen, hydrocarbon, carbon halide, hydrogen fluoride or rare gas (A) on the surface of the second interlayer insulating film 935 made of an organic insulating material.
r, He, Ne, etc.). Therefore, the cured film 935B contains hydrogen, nitrogen, hydrocarbon, halogenated carbon, hydrogen fluoride, or a rare gas (Ar, He, N
e) is considered to contain the gas element.

[Embodiment 4] In accordance with Embodiment 1, up to the second interlayer insulating film 935 is formed. Next, as shown in FIG. 12, a DLC film 936B may be formed as an insulating film 936 over the second interlayer insulating film 935.

[0096] As a feature of the DLC film has a peak of asymmetric per 1550 cm ^-1, a Raman spectrum distribution with a shoulder per 1300 cm ^-1. In addition, it shows a hardness of 15 to 25 GPa when measured with a micro hardness tester,
It has the feature of excellent chemical resistance. Further, the DLC film can be formed by a CVD method or a sputtering method, and can be formed in a temperature range from room temperature to 100 ° C. or less. As a film formation method, a method such as a sputtering method, an ECR plasma CVD method, a high-frequency plasma CVD method, or an ion beam evaporation method may be used, and the film may be formed to a thickness of about 5 to 50 nm.

[Embodiment 5] In accordance with Embodiment 1, up to the second interlayer insulating film 935 is formed. Next, as shown in FIG. 13, the surface of the second interlayer insulating film 935 is subjected to plasma treatment to modify the surface to form a cured film 935B, and then the cured film 9 is formed.
A DLC film 936B may be formed on 35B. In addition,
The DLC film 936B is formed by a sputtering method,
5 to 50 nm using a method such as a CR plasma CVD method, a high-frequency plasma CVD method, or an ion beam evaporation method.
It may be formed with a film thickness of about.

[Embodiment 6] After the first insulating layer 947 is formed in accordance with the process of Embodiment 1, the surface of the first insulating layer 947 is modified by performing a plasma treatment on the surface of the first insulating layer 947. An example of the operation will be described with reference to FIG.

Although the first insulating layer 947 is formed using an organic resin insulating film, it generates moisture and gas,
There is a problem that moisture or gas is easily generated by heat generated when the light emitting device is actually used.

Therefore, after performing the heat treatment, a plasma treatment is performed to modify the surface of the first insulating layer 947 as shown in FIG. Plasma treatment is performed in one or more kinds of gases selected from hydrogen, nitrogen, halogenated carbon, hydrogen fluoride, and a rare gas.

As a result, the surface of the first insulating layer 947 is densified, and a cured film containing one or more kinds of gas elements selected from hydrogen, nitrogen, halogenated carbon, hydrogen fluoride, or a rare gas is formed. Generation of moisture or gas (oxygen) from the inside can be prevented, and deterioration of the light-emitting element can be prevented.

This embodiment can be used in combination with any of the first to sixth embodiments.

[Embodiment 7] In this embodiment, a method for crystallizing a semiconductor film to be an active layer of a TFT using a catalyst element and thereafter reducing the concentration of the catalyst element in the obtained crystalline semiconductor film will be described. I do.

In FIG. 14A, a substrate 1100 is
Preferably, barium borosilicate glass, aluminoborosilicate glass, quartz, or the like can be used. On the surface of the substrate 100, an inorganic insulating film with a thickness of 10 to 200 nm is formed as a base insulating film 1101. An example of a suitable base insulating film is a silicon oxynitride film formed by a plasma CVD method, in which a first silicon oxynitride film formed of SiH ₄ , NH ₃ , and N ₂ O is formed to a thickness of 50 nm. ,
Next, a second silicon oxynitride film formed of SiH ₄ and N ₂ O with a thickness of 100 nm is applied.
The base insulating film 1101 is provided so that alkali metal contained in the glass substrate does not diffuse into a semiconductor film formed thereover. The base insulating film 1101 can be omitted when quartz is used as the substrate.

Next, a silicon nitride film 1102 is formed on the base insulating film 1101. The silicon nitride film 102 further contains oxygen contained in the base insulating film 1101 in order to prevent a catalyst element (typically, nickel) used in a later semiconductor film crystallization step from permeating the base insulating film 1101. It is formed for the purpose of preventing adverse effects. Note that the silicon nitride film 1102 is formed by a plasma CVD method.
It may be formed with a thickness of 5 nm.

Next, an amorphous semiconductor film 1103 is formed over the silicon nitride film 1102. Amorphous semiconductor film 1102
Uses a semiconductor material containing silicon as a main component. Typically, an amorphous silicon film or an amorphous silicon germanium film is applied, and a plasma CVD method or a low pressure CVD method is used.
It is formed to a thickness of 10 to 100 nm by a method or a sputtering method. In order to obtain high-quality crystals, the amorphous semiconductor film 110
The concentration of impurities such as oxygen and nitrogen contained in 3 is 5 × 10 ¹⁸
It is better to reduce it to / cm ³ or less. These impurities are factors that hinder the crystallization of the amorphous semiconductor and increase the density of trapping centers and recombination centers even after crystallization. For this purpose, not only is a high-purity material gas used, but also a mirror surface treatment (electric polishing treatment) in the reaction chamber and an ultra-high vacuum compatible CV equipped with an oil-free vacuum exhaust system.
It is desirable to use a D device. Note that the base insulating film 11
From 01 to the amorphous semiconductor film 1103, continuous film formation can be performed without opening to the atmosphere.

Thereafter, a metal element having a catalytic action for promoting crystallization is added to the surface of the amorphous silicon film 1103 (FIG. 14B). Examples of metal elements having a catalytic action for promoting crystallization of a semiconductor film include iron (Fe) and nickel (N
i), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (O
s), iridium (Ir), platinum (Pt), copper (C
u), gold (Au), or the like, and one or more selected from them can be used. Typically, nickel is used, and a nickel acetate salt solution containing 1 to 100 ppm by weight of nickel is applied with a spinner to form a catalyst-containing layer 1.
104 is formed. In this case, as a surface treatment of the amorphous silicon film 1103, an extremely thin oxide film is formed with an aqueous solution containing ozone, and the oxide film is mixed with hydrofluoric acid and a hydrogen peroxide solution in order to improve the familiarity of the solution. To form a clean surface, and then treat again with an ozone-containing aqueous solution to form an extremely thin oxide film. Since the surface of a semiconductor film such as silicon is hydrophobic in nature, a nickel acetate solution can be uniformly applied by forming an oxide film in this manner.

Of course, the catalyst containing layer 1104 is not limited to such a method, and may be formed by a sputtering method, an evaporation method, a plasma treatment, or the like.

A heat treatment for crystallization is performed while maintaining the state in which the amorphous silicon film 1103 and the catalyst element-containing layer 1104 are in contact with each other. As a heat treatment method, a furnace annealing method using an electric furnace or an RTA method using a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, a high-pressure mercury lamp, or the like is employed. Alternatively, a gas heating RTA using a heated inert gas can be applied.

When the RTA method is used, a heating lamp light source is turned on for 1 to 60 seconds, preferably 30 to 60 seconds.
It is repeated 1 to 10 times, preferably 2 to 6 times. Although the light emission intensity of the lamp light source is arbitrary, the semiconductor film is instantaneously heated to 600 to 1000 ° C., preferably 650 to 75 ° C.
Heat to about 0 ° C. Even at such a high temperature, the semiconductor film is only instantaneously heated, and the substrate 1100 itself is not distorted and deformed. Thus, the amorphous semiconductor film is crystallized, and FIG.
Although a crystalline silicon film 1105 shown in FIG. 4C can be obtained, crystallization by such a process can be achieved only by providing a catalyst element-containing layer.

When the furnace annealing method is used as another method, one hour at 500 ° C. prior to the heat treatment.
A heat treatment for about an hour is performed to form an amorphous silicon film 1103.
The hydrogen contained in is released. Then, using an electric furnace in a nitrogen atmosphere at 550 to 600 ° C., preferably 5 to 600 ° C.
Heat treatment at 80 ° C. for 4 hours to perform amorphous silicon film 11
03 is crystallized. Thus, a crystalline silicon film 1105 shown in FIG. 14C is formed.

In order to further increase the crystallization rate (the ratio of the crystal component in the total volume of the film) and repair defects remaining in the crystal grains, the crystalline silicon film 1105 may be irradiated with laser light. It is valid.

In the crystalline silicon film 1105 thus obtained, the catalyst element (nickel in this case) remains at an average concentration exceeding 1 × 10 ¹⁹ / cm ³ . If the catalyst element remains, the characteristics of the TFT may be adversely affected, so that the concentration of the catalyst element in the semiconductor layer needs to be reduced. Therefore, a method for reducing the concentration of the catalytic element in the semiconductor layer following the crystallization step will be described.

First, a thin layer 1106 is formed on the surface of the crystalline silicon film 1105 as shown in FIG.
In this specification, a thin layer 1106 provided over a crystalline silicon film 1105 is a layer provided so that the crystalline silicon film 1105 is not etched when a gettering site is removed later. I do.

The thickness of the barrier layer 1106 is about 1 to 10 nm, and a chemical oxide formed by simply treating with ozone water may be used as the barrier layer. Also,
Chemical oxide can be similarly formed by treating with an aqueous solution in which a hydrogen peroxide solution is mixed with sulfuric acid, hydrochloric acid, nitric acid or the like. As another method, the plasma treatment in an oxidizing atmosphere or the oxidation treatment by generating ozone by ultraviolet irradiation in an oxygen-containing atmosphere may be performed. Further, a barrier layer may be formed by heating to about 200 to 350 ° C. using a clean oven to form a thin oxide film. Alternatively, an oxide film of about 1 to 5 nm may be deposited as a barrier layer by a plasma CVD method, a sputtering method, an evaporation method, or the like. In any case, in the gettering step, the catalyst element can move to the gettering site side, and in the gettering site removing step, the etchant does not soak (protects the crystalline silicon film 1105 from the etchant). For example, a chemical oxide film, a silicon oxide film (SiOx), or a porous film formed by treatment with ozone water may be used.

Next, a second semiconductor film containing a rare gas element at a concentration of 1 × 10 ²⁰ / cm ³ or more (typically, a non-conductive layer) as a gettering site 1107 on the barrier layer 1106 by sputtering. (Amorphous silicon film) having a thickness of 25 to 250 nm. Gettering site 1 to be removed later
In order to increase the etching selectivity with respect to the crystalline silicon film 1105, it is preferable to form a film 107 having a low density.

Note that the rare gas element itself is inactive in the semiconductor film, and therefore does not adversely affect the crystalline silicon film 1105. As the rare gas element, one or a plurality of helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) are used. The present invention is characterized in that these rare gas elements are used as an ion source to form a gettering site, and that a semiconductor film containing these elements is formed and this film is used as a gettering site.

In order to surely achieve gettering, it is necessary to perform a heat treatment thereafter. The heat treatment is performed by a furnace annealing method or an RTA method. When the furnace annealing method is used, 450 to 600 ° C. in a nitrogen atmosphere
For 0.5 to 12 hours. When the RTA method is used, a heating lamp light source is used for 1 to 60 seconds.
It is preferably turned on for 30 to 60 seconds, and it is turned on 1 to 10 times,
Preferably, it is repeated 2 to 6 times. The emission intensity of the lamp light source is arbitrary, but the semiconductor film is
The temperature is set to about 000 ° C, preferably about 700 to 750 ° C.

In the gettering, the catalytic element in the region to be gettered (capture site) is released by thermal energy and moves to the gettering site by diffusion. Therefore, gettering depends on the processing temperature, and the higher the temperature, the faster the gettering proceeds. In the present invention, the distance that the catalytic element moves during gettering is about the thickness of the semiconductor film, and the gettering can be completed in a relatively short time (FIG. 14).
(E)).

Note that 1 × 10 ¹⁹
/ cm ³ -1 × 10 ²¹ / cm ³ , preferably 1 × 10 ²⁰ / cm ³ -1
The semiconductor film 1107 containing a rare gas element at a concentration of × 10 ²¹ / cm ³ , more preferably 5 × 10 ²⁰ / cm ³ does not crystallize. This is considered to be because the rare gas element is not re-emitted even in the above-mentioned processing temperature range and remains in the film to inhibit crystallization of the semiconductor film.

After the end of the gettering step, the gettering sites 1107 are selectively removed by etching. As an etching method, dry etching without plasma using ClF ₃ , hydrazine, tetraethylammonium hydroxide (chemical formula (C
It can be performed by wet etching using an alkaline solution such as an aqueous solution containing H ₃ ) ₄ NOH). At this time, the barrier layer 1106 functions as an etching stopper. The barrier layer 1106 may be removed with hydrofluoric acid thereafter.

Thus, as shown in FIG. 14F, a crystalline silicon film 1108 in which the concentration of the catalytic element has been reduced to 1 × 10 ¹⁷ / cm ³ or less can be obtained. The crystalline silicon film 1108 thus formed is formed as a thin rod-shaped crystal or a thin flat rod-shaped crystal by the action of a catalyst element, and each crystal grows in a specific direction when viewed macroscopically.

This embodiment can be used in combination with Embodiments 1 to 6.

[Embodiment 8] In this embodiment, a light emitting device manufactured by combining Embodiments 1 to 6 to the state shown in FIG. 6B is completed by assembling a sealing material and an external input wiring. The method will be described in detail with reference to FIG.

FIG. 9A is a top view of a light-emitting panel in which an element substrate is sealed, and FIG. 9B is a cross-sectional view of FIG. 9A taken along the line AA ′. Reference numeral 801 indicated by a dotted line denotes a source side driver circuit, 802 denotes a pixel portion, and 803 denotes a gate side driver circuit. Reference numeral 804 denotes a sealing substrate, 805 denotes a sealant, and an inside surrounded by the sealant 805 is a space 807.

A wiring (not shown) for transmitting signals input to the source-side drive circuit 801 and the gate-side drive circuit 803 allows a video signal or the like from an FPC (flexible printed circuit) 809 serving as an external input terminal. Receive a clock signal. Note that although a state where the FPC is connected to the light-emitting panel is shown here, a module in which an IC (integrated circuit) is directly mounted via the FPC is referred to as a light-emitting device in this specification.

Next, the cross-sectional structure will be described with reference to FIG. A pixel portion 802 and a gate side driver circuit 803 are formed above the substrate 810. The pixel portion 802 includes a plurality of pixels including a current control TFT 811 and a first electrode 812 which is electrically connected to a drain thereof. It is formed. The gate side drive circuit 803 is an n-channel type T
It is formed using a CMOS circuit in which an FT 813 and a p-channel TFT 814 are combined.

After the first insulating layer 815 is formed at both ends of the first electrode 812, the insulating film 821, the organic compound layer 816, and the second electrode 817 are formed on the first electrode 812.
Is formed, and the light emitting element 818 is formed.

It is to be noted that the second electrode 817 functions as a wiring common to all pixels, and the FPC 8 via the connection wiring 808.
09 is electrically connected.

[0130] Note that a sealing substrate 804 made of glass is adhered by a sealant 805. Note that an ultraviolet curable resin or a thermosetting resin is preferably used as the sealant 805. Further, if necessary, a spacer made of a resin film may be provided in order to secure an interval between the sealing substrate 804 and the light emitting element 818. The space 807 inside the sealant 805 is filled with an inert gas such as nitrogen or a rare gas. Further, it is desirable that the sealant 805 is a material that does not transmit moisture and oxygen as much as possible.

With the structure described above, the light emitting element is
The light emitting element can be completely shut off from the outside by enclosing the light emitting element, and deterioration of the light emitting element due to moisture or oxygen entering from the outside can be prevented. Therefore, a highly reliable light-emitting device can be obtained.

The structure of this embodiment can be implemented by combining the structures of the first to sixth embodiments.

[Embodiment 9] Here, a more detailed top structure of a pixel portion of a light emitting device formed by using the present invention is shown in FIG.
FIG. 10A shows a circuit diagram. 10, the switching TFT 704 provided on the substrate is the switching (n-channel) TFT 1002 of FIG.
It is formed by using. Therefore, for the description of the structure, the description of the switching (n-channel) TFT 1002 may be referred to. A wiring denoted by reference numeral 703 is a gate wiring for electrically connecting the gate electrodes 704a and 704b of the switching TFT 704.

Although the present embodiment has a double gate structure in which two channel formation regions are formed, a single gate structure in which one channel formation region is formed or a triple gate structure in which three channel formation regions are formed. good.

The source of the switching TFT 704 is connected to the source wiring 715, and the drain is connected to the drain wiring 705. Further, the drain wiring 705 is electrically connected to the gate electrode 707 of the current controlling TFT 706. Note that the current control TFT 706 is formed using the current control (p-channel type) TFT 1003 in FIG. Therefore, for the description of the structure, the description of the current control (p-channel type) TFT 1003 may be referred to. In this embodiment, a single gate structure is used, but a double gate structure or a triple gate structure may be used.

The current control TFT 706 has a source electrically connected to the current supply line 716 and a drain electrically connected to the drain wiring 717. Further, a drain wiring 717 is a first electrode (anode) 718 indicated by a dotted line.
Is electrically connected to

At this time, a storage capacitor (capacitor) is formed in a region indicated by 719. Capacitor 719
Represents the semiconductor film 7 electrically connected to the current supply line 716
20, formed between an insulating film (not shown) in the same layer as the gate insulating film and the gate electrode 707; Further, a capacitor formed by the gate electrode 707, the same layer (not shown) as the first interlayer insulating film, and the current supply line 716 can be used as a storage capacitor.

The structure of this embodiment is the same as that of Embodiments 1 to
It is possible to implement by combining the configurations of the sixth embodiment.

[Embodiment 10] Since a light emitting device using a light emitting element is of a self-luminous type, it has better visibility in a bright place and a wider viewing angle than a liquid crystal display device. Therefore, it can be used for display portions of various electric appliances.

Electric appliances using the light emitting device manufactured according to the present invention include a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproducing device (car audio, audio component, etc.), a notebook type personal computer. Computers, game consoles, personal digital assistants (mobile computers, mobile phones, portable game consoles, electronic books, etc.),
An image reproducing device provided with a recording medium (specifically, a device provided with a display device capable of reproducing a recording medium such as a digital video disk (DVD) and displaying the image) is provided. In particular, in a portable information terminal in which a screen is often viewed from an oblique direction, since a wide viewing angle is regarded as important, it is preferable to use a light emitting device having a light emitting element. FIG. 11 shows specific examples of these electric appliances.

FIG. 11A shows a display device,
01, a support base 2002, a display unit 2003, a speaker unit 2004, a video input terminal 2005, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2003. Since a light-emitting device having a light-emitting element is a self-luminous type, it does not require a backlight and can have a thinner display portion than a liquid crystal display device. The display device includes all information display devices for personal computers, TV broadcast reception, advertisement display, and the like. When used for TV broadcast reception, the light emitting device of the present invention can be applied even when the screen size is 30 inches.

FIG. 11B shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103,
An operation key 2104, an external connection port 2105, a shutter 2106, and the like are included. The light-emitting device manufactured according to the present invention can be used for the display portion 2102.

FIG. 11C shows a notebook personal computer, which includes a main body 2201, a housing 2202, and a display section 2.
203, keyboard 2204, external connection port 220
5, including a pointing mouse 2206 and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2203.

FIG. 11D shows a mobile computer, which includes a main body 2301, a display portion 2302, and a switch 230.
3, an operation key 2304, an infrared port 2305, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2302.

FIG. 11E shows a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, and includes a main body 2401, a housing 2402, a display portion A 2403, a display portion B 2404, and a recording medium ( DVD, etc.) reading unit 240
5, operation keys 2406, a speaker unit 2407, and the like. The display portion A2403 mainly displays image information and the display portion B2404 mainly displays character information. The light-emitting device manufactured according to the present invention employs these display portions A and B240.
3, 2404. Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

FIG. 11F shows a goggle-type display (head-mounted display).
1, including a display unit 2502 and an arm unit 2503. The light-emitting device manufactured according to the present invention can be used for the display portion 2502.

FIG. 11G shows a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, and an image receiving portion 260.
6, a battery 2607, a voice input unit 2608, operation keys 2609, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2602.

FIG. 11H shows a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, a voice input portion 2704, a voice output portion 2705, operation keys 2706,
An external connection port 2707, an antenna 2708, and the like are included.
The light-emitting device manufactured according to the present invention can be used for the display portion 2703. Note that the display portion 2703 displays white characters on a black background, so that power consumption of the mobile phone can be suppressed.

If the emission luminance of the organic material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front-type or rear-type projector.

In addition, the above-mentioned electric appliances are available on the Internet or C
Information distributed through an electronic communication line such as an ATV (cable television) is frequently displayed, and in particular, opportunities to display moving image information are increasing. Since the response speed of the organic material is extremely high, the light-emitting device is preferable for displaying moving images.

In the light emitting device, since the light emitting portion consumes power, it is preferable to display information so that the light emitting portion is reduced as much as possible. Therefore, when a light emitting device is used for a portable information terminal, particularly a display portion mainly for character information such as a mobile phone or a sound reproducing device, the light emitting portion is driven to form character information with a non-light emitting portion as a background. Is preferred.

As described above, the applicable range of the light emitting device manufactured by using the present invention is extremely wide, and it can be used for electric appliances in various fields. Further, in the electric appliance of the present embodiment, the light emitting devices shown in Examples 1 to 9 can be used for the display unit.

[0153]

As described above, the first electrode (anode) and the first insulating layer have a thickness of 1 to 10 nm, preferably 2 to 10 nm.
By providing the second insulating layer having a thickness of about 3 nm through which a tunnel current can flow, fine irregularities on the surface of the first electrode (anode) can be flattened, and the organic compound layer can be formed uniformly. Even when the first interlayer insulating film 104 or the second interlayer insulating film 105 has irregularities or foreign matter of several tens to several hundreds of nm, a dark spot or a first spot is formed by forming the second insulating layer. And the second electrode can be prevented from being short-circuited and the light emitting element from turning off.

Further, by providing the second insulating layer 112, degassing from the first insulating layer 109 formed of an organic resin material such as polyimide, polyamide, or acrylic is prevented, and the organic compound layer 113 is formed. Deterioration can be prevented. In addition, it is possible to prevent Li and Mg, which are elements constituting the second electrode 114, from diffusing to the current control TFT 101 side.

[Brief description of the drawings]

FIG. 1 illustrates an embodiment of a method for manufacturing a light-emitting device.

FIG. 2 illustrates an example of a conventional light emitting device.

FIG. 3 illustrates a manufacturing process of a light-emitting device.

FIG. 4 illustrates a manufacturing process of a light-emitting device.

FIG. 5 illustrates a manufacturing process of a light-emitting device.

FIG. 6 illustrates a manufacturing process of a light-emitting device.

FIG. 7 illustrates an embodiment of a manufacturing process of a light-emitting device.

FIG. 8 illustrates an embodiment of a manufacturing process of a light-emitting device.

FIG. 9 illustrates a sealing structure of a light-emitting device.

FIG. 10 illustrates a structure of a pixel portion of a light-emitting device.

FIG. 11 illustrates an example of an electric appliance.

FIG. 12 illustrates an embodiment of a manufacturing process of a light-emitting device.

FIG. 13 illustrates an embodiment of a manufacturing process of a light-emitting device.

FIG. 14 illustrates an embodiment of a manufacturing process of a light-emitting device.

Claims (22)

[Claims] 1. A first electrode formed on an insulating surface, and a first electrode having a tapered edge covering an end of the first electrode.
An insulating layer, a second insulating layer formed on the first electrode and the first insulating layer, and formed of one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride; An organic compound layer formed on the second insulating layer;
A second electrode formed on the organic compound layer. 2. A first electrode formed on an insulating surface, and a first electrode having a tapered edge covering an end of the first electrode.
An insulating layer formed on the first electrode and the first insulating layer, a second insulating layer mainly containing carbon, and an organic compound layer formed on the second insulating layer. And a second electrode formed on the organic compound layer. 3. A light emitting device according to claim 1, wherein said insulating surface is formed of polyimide or acrylic. 4. The light emitting device according to claim 1, wherein the insulating surface is formed of silicon nitride or silicon oxynitride. 5. A thin film transistor having a source region and a drain region, an interlayer insulating film over the source region and the drain region, a drain electrode having an opening formed in the interlayer insulating film and connected to the drain region, A first electrode formed on the interlayer insulating film and connected to the drain electrode; an opening formed on the first electrode; and a tapered edge covering an end of the first electrode. A first insulating layer, a second insulating layer formed on the first electrode and the first insulating layer, and formed of one or more kinds selected from silicon oxide, silicon nitride, and silicon oxynitride; A light-emitting device comprising: an organic compound layer formed on the second insulating layer; and a second electrode formed on the organic compound layer. 6. A thin film transistor having a source region and a drain region, an interlayer insulating film on the source region and the drain region, an opening formed in the interlayer insulating film, and a drain electrode connected to the drain region. A first electrode formed on the interlayer insulating film and connected to the drain electrode; an opening formed on the first electrode; and a tapered edge covering an end of the first electrode. A first insulating layer, a second insulating layer formed on the first electrode and the first insulating layer and mainly containing carbon, and an organic compound formed on the second insulating layer A light-emitting device comprising: a layer; and a second electrode formed on the organic compound layer. 7. The light emitting device according to claim 5, wherein said interlayer insulating film is formed of polyimide or acrylic. 8. The interlayer insulating film according to claim 5, wherein the interlayer insulating film includes a first layer made of polyimide or acrylic;
A light-emitting device comprising a second layer made of silicon nitride or silicon oxynitride. 9. The light emitting device according to claim 1, wherein the first insulating layer is formed of polyimide or acrylic. 10. The light emitting device according to claim 1, wherein the second insulating layer has a thickness of 1 to 10 nm. 11. The light emitting device according to claim 1, wherein the second insulating layer has a thickness of 2 to 3 nm. 12. The light-emitting device according to claim 1, wherein the light-emitting device is a display device, a digital still camera, a notebook personal computer, a mobile computer, a portable image reproducing device including a recording medium, A light emitting device characterized by being a kind selected from a goggle type display, a video camera, and a mobile phone. 13. A first electrode is formed on an insulating surface, a first insulating layer covering an end of the first electrode and having a tapered edge is formed, and the first electrode and the first electrode are formed. Forming a second insulating layer of one or more selected from silicon oxide, silicon nitride, and silicon oxynitride on the first insulating layer; forming an organic compound layer on the second insulating layer; A method for manufacturing a light-emitting device, wherein a second electrode is formed over the organic compound layer. 14. A first electrode is formed on an insulating surface, a first insulating layer covering an end of the first electrode and having a tapered edge is formed, and the first electrode and the first electrode are formed. Forming a second insulating layer mainly containing carbon on the first insulating layer, forming an organic compound layer on the second insulating layer, and forming a second electrode on the organic compound layer; A method for manufacturing a light-emitting device, comprising: 15. A thin film transistor having a source region and a drain region, wherein an interlayer insulating film is formed on the source region and the drain region, an opening reaching the drain region is formed in the interlayer insulating film, and then a drain electrode is formed. Forming a first electrode connected to the drain electrode on the interlayer insulating film, forming an insulating layer covering the first electrode connected to the drain electrode, and then forming an opening on the first electrode; Forming a first insulating layer, the first insulating layer
A second insulating layer made of one or more of silicon oxide, silicon nitride, and silicon oxynitride is formed on the first electrode and the first insulating layer, and a second electrode is formed on the organic compound layer. Forming a light emitting device. 16. A thin film transistor having a source region and a drain region, an interlayer insulating film is formed on the source region and the drain region, an opening reaching the drain region is formed in the interlayer insulating film, and then a drain electrode is formed. Forming a first electrode connected to the drain electrode on the interlayer insulating film, forming an insulating layer covering the first electrode connected to the drain electrode, and then forming an opening on the first electrode; Forming a first insulating layer, the first insulating layer
Forming a second insulating layer containing carbon as a main component on the first electrode and the first insulating layer, and forming a second electrode on the organic compound layer. . 17. The method for manufacturing a light emitting device according to claim 15, wherein the interlayer insulating film is formed of polyimide or acrylic. 18. The semiconductor device according to claim 15, wherein the interlayer insulating film is formed of a first layer made of polyimide or acrylic and a second layer made of silicon nitride or silicon oxynitride. For manufacturing a light emitting device. 19. The method for manufacturing a light emitting device according to claim 13, wherein the first insulating layer is formed of polyimide or acrylic. 20. The method for manufacturing a light-emitting device according to claim 13, wherein the second insulating layer is formed with a thickness of 1 to 10 nm. 21. The method for manufacturing a light-emitting device according to claim 13, wherein the second insulating layer is formed with a thickness of 2 to 3 nm. 22. The method for manufacturing a light-emitting device according to claim 13, wherein the second insulating layer is formed by a plasma CVD method or a sputtering method.