JP2008053526A - Fabricating method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of highly accurately executing thin film processing in a simple process without using a photomask and a resist, and to provide a method of fabricating a semiconductor device at a low cost. <P>SOLUTION: A first layer 101 is formed on a substrate 100, a light absorbing layer 103 is formed on the first layer 101, and the light absorbing layer 103 is selectively irradiated with a laser beam 105. The light absorbing layer 103 absorbs the energy of the laser beam 105, and thus, one part thereof is physically dissociated based on emission of a gas in the light absorbing layer 103 and sublimation or evaporation of the light absorbing layer 103. That means, the one part of the light absorbing layer is irradiated with the laser beam 105 to remove the one part of the irradiated layer. In this way, the remaining light absorbing layer 113 is used as a mask to etch the first layer 101, thereby processing the first layer 101 into a desired site and shape without using a conventional photolithographic technique. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device having a semiconductor element.

  2. Description of the Related Art Conventionally, a so-called active matrix driving display panel or semiconductor integrated circuit including a thin film transistor (hereinafter also referred to as “TFT”) or a semiconductor element typified by a MOS transistor has a light exposure process using a photomask ( Hereinafter, it is manufactured by forming a resist mask by a photolithography process and selectively etching various thin films.

  In the photolithography process, a resist is applied to the entire surface of the substrate and pre-baked, and then the resist is exposed to ultraviolet rays and the like through a photomask, and developed to form a resist mask. Thereafter, using the resist mask as a mask, a thin film (thin film formed of a semiconductor material, an insulator material, or a conductor material) existing in a portion other than a semiconductor layer or a portion to be a wiring is removed by etching, and the semiconductor layer or Wiring is formed.

Further, the present applicant has disclosed a thin film processing method for forming a groove by irradiating a light-transmitting conductive film with a linear beam using a laser beam having a wavelength of 400 μm or less in Patent Document 1 and Patent Document 2. It is described.
JP-A 63-84789 JP-A-2-317

  However, a photomask using a photolithography technique is very expensive because it has a fine shape and requires high accuracy of the shape. Furthermore, in order to manufacture a semiconductor device, it is necessary to prepare a plurality of expensive photomasks, which imposes a very large industrial burden on the cost.

Further, when the design of the semiconductor device is changed, it is naturally necessary to prepare a new photomask in accordance with the processing pattern to be changed. As described above, since the photomask is a modeled object formed with a fine shape with high accuracy, a considerable amount of time is required for manufacturing. In other words, not only a financial burden but also a time delay risk is borne in exchange of a photomask due to a design change or design deficiency.

  In addition, when the laser beam emitted from the laser oscillator is focused at one or more locations by the optical system and the opening is formed by irradiating the laser beam, the effects of variations in pointing stability, etc., of the laser oscillator Therefore, there is a problem that the position where the laser beam is condensed fluctuates.

  In addition, when a semiconductor film having a desired shape is formed by etching a semiconductor film using a conventional photolithography process, a resist is applied to the surface of the semiconductor film. At this time, since the surface of the semiconductor film is directly exposed to the resist, there is a problem that the semiconductor film is contaminated by impurities such as oxygen, carbon, and heavy metal elements contained in the resist. Due to this contamination, impurity elements are mixed in the semiconductor film, and the characteristics of the semiconductor element are deteriorated. In particular, TFTs have a problem of causing variation and deterioration in transistor characteristics.

  Therefore, the present invention presents a method for performing thin film processing with high accuracy in a simple process without using a photomask or a resist. In addition, a method for manufacturing a semiconductor device at low cost is proposed.

  In the present invention, a first layer is formed over a substrate, a light absorption layer is formed over the first layer, and the light absorption layer is selectively irradiated with a laser beam. When the light absorption layer absorbs the energy of the laser beam, a part of the light absorption layer is physically dissociated due to gas emission in the light absorption layer, sublimation or evaporation of the light absorption layer, and the like. That is, a part of the light absorption layer is irradiated with a laser beam, and a part of the irradiation region is removed. By using the remaining light absorption layer as a mask and etching the first layer, the first layer can be processed into a desired location and shape without using a conventional photolithography technique.

  In addition, a laser beam is selectively irradiated to the light absorption layer using a laser irradiation apparatus having an electro-optic element. The electro-optic element can selectively control the position and area where the laser beam is irradiated by data designed by a CAD (calculation support design) apparatus. Therefore, it is possible to selectively irradiate the light absorption layer with a laser beam without using a photomask.

  According to one embodiment of the present invention, a first layer is formed over a substrate, a light absorption layer is formed over the first layer, the light absorption layer is selectively irradiated with a laser beam, and the light irradiated with the laser beam A part of an absorption layer is removed to expose a part of the light absorption layer, and the exposed light absorption layer and the first layer are etched to form a second layer. This is a manufacturing method.

  According to one embodiment of the present invention, a first layer is formed over a substrate, a light absorption layer is formed over the first layer, the light absorption layer is selectively irradiated with a laser beam, and the light irradiated with the laser beam In a method for manufacturing a semiconductor device, a part of an absorption layer is removed to expose a part of a first layer, and the exposed first layer is etched to form a second layer. is there.

  According to one embodiment of the present invention, a first layer is formed over a substrate, a light absorption layer is formed over the first layer, the laser absorption beam is selectively irradiated to the light absorption layer, and the laser beam is irradiated. A part of the light absorption layer is removed to form a light absorption layer having a first film thickness and a light absorption layer having a second film thickness that is thinner than the first film thickness. A method for manufacturing a semiconductor device is characterized in that the second layer is formed by etching the light absorption layer and the first layer using the mask as a mask.

  The second layer may be a stacked layer of an etched light absorption layer and a first layer. Further, after the second layer is formed, the light absorption layer of the second layer may be removed.

  The etching is wet etching or dry etching.

  The laser beam is emitted from a laser irradiation apparatus having an electro-optic element. The area and area of the electro-optic element that is irradiated with the laser beam are controlled by the control device. The laser beam is rectangular or linear.

  In the present invention, the display device refers to a device using a display element, that is, an image display device. In addition, a connector, for example, a module in which a flexible printed wiring (FPC), TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) is attached to the display panel, and a printed wiring board is attached to the end of the TAB tape or TCP. It is assumed that the display device includes all provided modules or modules in which an IC (Integrated Circuit) or a CPU is directly mounted on a display element by a COG (Chip On Glass) method.

  By irradiating the light absorption layer with a laser beam, the light absorption layer can be freely processed. Further, the processed light absorption layer can be used as a mask for processing a thin film.

  In addition, a laser irradiation apparatus having an electro-optic element that can selectively control the irradiation region of the laser beam is used, and the light absorption layer is selectively irradiated with data designed by a CAD (calculation support design) apparatus. Can do.

  For this reason, a layer having a desired shape is formed in a predetermined place by etching a thin film using a light absorption layer functioning as a mask formed by irradiation of a laser beam whose irradiation region is controlled by a gas optical element. It is possible to form.

  In addition, a plurality of regions can be obtained in a short time by irradiating the light absorption layer with a laser beam having a large beam spot area, such as a linear laser beam, a rectangular laser beam, a planar laser beam, or a beam of any shape. Thus, a semiconductor device can be manufactured with high productivity.

  Therefore, the thin film can be processed into an arbitrary shape without using a resist or a photomask that is necessary in the conventional photolithography technique. For this reason, since a photomask is not used, it is possible to reduce the time loss required for photomask replacement, and it is possible to produce a small amount of products. Further, since a resist and a resist developer are not used, a large amount of chemical solution or water is not required. Furthermore, the semiconductor film can be processed while avoiding the mixing of impurity elements into the semiconductor film by resist coating. As described above, the process can be greatly simplified and the cost can be reduced as compared with a process using a conventional photolithography technique.

  As described above, by using the present invention, thin film processing in manufacturing a semiconductor device can be accurately performed with a simple process. In addition, a semiconductor device can be manufactured at low cost with high throughput and yield.

  The best mode for carrying out the invention will be described below with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention should not be construed as being limited to the description of the embodiment modes. In the drawings, common portions are denoted by the same reference numerals, and detailed description thereof is omitted.

(Embodiment 1)
In this embodiment, a laser ablation patterning process (LAPP (Laser Ablation Patterning Process)) that processes a thin film using a laser beam without passing through a photolithography step is described in the following embodiments and examples. Show. 1 and 3 are cross-sectional views showing a step of selectively forming a layer having an arbitrary shape on a substrate. FIGS. 2 and 4 are electro-optical elements of a laser irradiation apparatus, and FIGS. It is a top view.

  As shown in FIG. 1A, a first layer 101 that functions as a base film on one side of a substrate 100, a second layer 102 over the first layer 101, and a light absorption layer 103 over the second layer 102. Form.

  As the substrate 100, a glass substrate, a plastic substrate, a metal substrate, a ceramic substrate, or the like can be used as appropriate. Further, a printed wiring board or FPC can be used. When the substrate 100 is a glass substrate or a plastic substrate, a large area substrate such as 320 mm × 400 mm, 370 mm × 470 mm, 550 mm × 650 mm, 600 mm × 720 mm, 680 mm × 880 mm, 1000 mm × 1200 mm, 1100 mm × 1250 mm, 1150 mm × 1300 mm is used. be able to.

  The first layer 101 that functions as a base film is not necessarily required, but is preferably provided because it has a function of preventing the substrate 100 from being etched when the second layer is etched later. The first layer 101 may be formed using a suitable material as appropriate. Typically, there are silicon oxide, silicon nitride, silicon oxynitride, aluminum nitride, and the like.

  For the second layer 102, a conductive material, a semiconductor material, or an insulating material is used as appropriate depending on a part to be manufactured such as an electrode, a pixel electrode, a wiring, an antenna, a semiconductor layer, an insulating layer, a partition wall of a plasma display, or a phosphor. What is necessary is just to form. Note that the second layer 102 may be a single layer or a stacked layer.

  The light absorption layer 103 is formed using a material that absorbs a laser beam irradiated later. As a material that absorbs the laser beam, a material having a band gap energy smaller than that of a laser beam to be irradiated later is used. The light absorption layer 103 is preferably formed using a material having a boiling point or a sublimation point lower than the melting point of the second layer 101. By using such a material, the laser beam can be absorbed while the second layer 101 is not melted, and part of the light absorption layer can be removed using the energy of the laser beam.

In this embodiment mode, it is preferable that a difference in etching rate between the light absorption layer 103 and the second layer 102 is large. Typically, the etching rate of the second layer 102 is preferably higher than the etching rate of the light absorption layer 103. Alternatively, the thickness of the second layer 102 is preferably smaller than the thickness of the light absorption layer 103. As a result, the second layer can be etched after the light absorption layer which functions as a mask is formed by irradiation with the laser beam.

  As the light absorption layer, a conductive material, a semiconductor material, or an insulator material can be used as appropriate. As the conductive material, titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), molybdenum (Mo), copper (Cu), chromium (Cr), neodymium (Nd), iron (Fe), Nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), silver (Ag), gold (Au), platinum (Pt), An element selected from cadmium (Cd), zinc (Zn), silicon (Si), germanium (Ge), zirconium (Zr), and barium (Ba) can be used. Further, it can be formed of a single layer or a stacked layer of an alloy material containing the element as a main component, a nitrogen compound, or the like. Indium oxide containing tungsten oxide (IWO), Indium zinc oxide containing tungsten oxide (IWZO), Indium oxide containing titanium oxide (ITO), Indium tin oxide containing titanium oxide (ITTiO) Indium tin oxide A light-transmitting conductive material such as a material (ITO), indium zinc oxide (IZO), or indium tin oxide added with silicon oxide (ITSO) can also be used.

The insulating material can be formed using a single layer of an oxygen compound, a carbon compound, or a halogen compound of the above element. Further, a stack of these can be used. Typically, zinc oxide, aluminum nitride, zinc sulfide (ZnS), silicon nitride (SiN), silicon oxide (SiO ₂ ), mercury sulfide (HgS), aluminum chloride (AlCl ₃ ), and the like are given. An insulating film in which particles capable of absorbing light are dispersed, typically a silicon oxide film in which silicon microcrystals are dispersed, can be used. Alternatively, an organic resin such as polyimide, polyamide, BCB (benzocyclobutene), or acrylic can be used. Further, siloxane, polysilazane, or the like can be used. Alternatively, an insulating layer in which a dye is dissolved or dispersed in an organic resin, siloxane, polysilazane, or the like can be used.

  As the semiconductor material, silicon, germanium, or the like can be used. In addition, an amorphous semiconductor, a semi-amorphous semiconductor in which an amorphous state and a crystalline state are mixed (also referred to as SAS), and a microcrystal in which a crystal grain of 0.5 nm to 20 nm can be observed in the amorphous semiconductor. A film having any state selected from a semiconductor and a crystalline semiconductor film can be used. Furthermore, acceptor-type elements or donor-type elements such as phosphorus, arsenic, and boron may be included.

  Further, the light absorption layer 103 absorbs a laser beam to be irradiated later, and emits a gas in the light absorption layer or sublimates or evaporates the light absorption layer by the energy of the laser beam, or a part of the light absorption layer or It is preferable to use a material capable of physically dissociating part of the layer in contact with the light absorption layer. By using such a material, the light absorption layer can be easily removed.

  As a light absorption layer capable of releasing gas in the light absorption layer by the energy of the laser beam, there is a layer formed of a material containing at least one of hydrogen and a rare gas element. Typically, a semiconductor layer containing hydrogen, a conductive layer containing noble gas or hydrogen, an insulating layer containing noble gas or hydrogen, and the like can be given. In this case, since the physical dissociation occurs in part of the light absorption layer as the gas is released in the light absorption layer, the light absorption layer can be easily removed.

As the light absorption layer that can be sublimated by the energy of the laser beam, a material having a low sublimation point of about 100 to 2000 ° C. is preferable. Alternatively, a material having a melting point of 1500 to 3500 ° C. and a thermal conductivity of 0.1 to 100 W / mK can be used. As a light absorption layer capable of sublimation, there is a material having a low sublimation point of about 100 to 2000 ° C., and typical examples thereof include aluminum nitride (AlN), zinc oxide (ZnO), zinc sulfide (ZnS), Examples include silicon nitride (SiN), mercury sulfide (HgS), and aluminum chloride (AlCl ₃ ). Examples of materials having a boiling point of 1000 to 2700 ° C. and a thermal conductivity of 0.1 to 100 W / mK include germanium (Ge), silicon oxide (SiO ₂ ), chromium (Cr), and titanium (Ti). is there.

  As a method for forming the light absorption layer 103, a coating method, an electroplating method, a PVD method (Physical Vapor Deposition), or a CVD method (Chemical Vapor Deposition) is used.

  Next, the light absorption layer 103 is irradiated with a laser beam 105.

  As the laser beam 105, one having energy absorbed by the light absorption layer 103 is appropriately selected. Typically, irradiation is performed by appropriately selecting a laser beam in an ultraviolet region, a visible region, or an infrared region.

  Here, the laser irradiation apparatus used in the present invention is described below. The laser irradiation apparatus used in the present invention can control the area and position of the laser beam irradiation using data designed by the CAD apparatus. By using such a laser irradiation apparatus, a laser beam can be selectively irradiated without using a photomask.

  A typical example of such a laser irradiation apparatus will be described with reference to FIG. FIG. 9 is a perspective view showing an example of the manufacturing apparatus of the present invention. The emitted laser beam is output from a laser oscillator 1003 (YAG laser device, excimer laser device, etc.), and a first optical system 1004 for making the beam shape rectangular and a second optical system 1005 for shaping. And the third optical system 1006 for making parallel rays, and the optical path is bent in the vertical direction by the reflection mirror 1007. Thereafter, the laser beam is passed through an electro-optic element 1008 that selectively adjusts the area and position of the laser beam irradiated on the light absorption layer 103, and the irradiated surface is irradiated with the laser beam.

As the laser oscillator 1003, gas lasers such as Ar laser, Kr laser, and excimer laser (KrF, ArF, KrF, XeCl), single crystal YAG, YVO ₄ , forsterite (Mg ₂ SiO ₄ ), YAlO ₃ , GdVO ₄ In addition, one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta are added as dopants to polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , and GdVO _4. One or more of laser diodes, semiconductor laser oscillators such as GaN, GaAs, GaAlAs, InGaAsP, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser, copper vapor laser or gold vapor laser What is oscillated from can be used. When a solid-state laser whose laser medium is a solid is used, there are advantages that a maintenance-free state can be maintained for a long time and output is relatively stable.

As the laser beam 105, a continuous wave laser beam or a pulsed laser beam can be used as appropriate. In a pulsed laser beam, a frequency band of several tens of Hz to several kHz is usually used, but an oscillation frequency of 10 MHz or higher, a pulse width of a frequency range of picoseconds or a femtosecond (10 ⁻¹⁵⁾ , which is significantly higher than that. A pulsed laser having a frequency on the order of seconds) may be used. In particular, a laser beam emitted from a pulse laser oscillated with a pulse width of 1 femtosecond to 10 picoseconds provides a high-intensity laser beam, which produces a nonlinear optical effect (multiphoton absorption), and the energy of the laser beam. Even the light absorption layer having a larger band gap energy can be removed by the energy of the laser beam.

The control device 1016 is typically a computer and includes a storage unit (RAM, ROM, etc.) for storing design data of the semiconductor device, and a microprocessor including a CPU. By inputting an electrical signal based on CAD data for designing a semiconductor device to the electro-optic element from the control device 1016, the position and area of the laser beam irradiated to the substrate by the electro-optic element is controlled. For example, when a stage on which a substrate to be processed is fixed is moved, the emission timing of the laser oscillator, the electric signal input to the electro-optical element, and the moving speed of the stage are synchronized.

The electro-optical element 1008 functions as an optical shutter or an optical reflector and functions as a variable mask by inputting an electrical signal based on design CAD data of the semiconductor device. The area and position of the laser beam can be changed by changing the electric signal input to the electro-optical element serving as an optical shutter by the control device 1016. That is, the area and position where the thin film is processed can be selectively changed. Therefore, the shape of the laser beam can be a linear shape, a rectangular shape, or an arbitrary shape, and a laser beam having a complicated shape can be irradiated.

The electro-optical element 1008 includes an element that can selectively adjust an area through which light is transmitted, for example, an element having a liquid crystal material or an electrochromic material. Further, there is an element that can selectively adjust light reflection, for example, a digital micromirror device (also referred to as DMD). DMD is a kind of spatial light modulator, and is a device in which a large number of small mirrors called micromirrors that rotate around a fixed axis by an electrostatic field effect or the like are arranged in a matrix on a semiconductor substrate such as Si. As another electro-optical element, a PLZT element that is an optical element that modulates transmitted light by an electro-optical effect can be used. The PLZT element is an oxide ceramic containing lead, lanthanum, zircon, and titanium, and is a device called PLZT from the initials of each element symbol. The PLZT element transmits light with a transparent ceramic, but when a voltage is applied, the direction of polarization of light can be changed, and an optical shutter is configured by combining with a polarizer. However, the electro-optic element 1008 is a device that can withstand even a laser beam that passes therethrough.

  The electro-optic element 1008 can have the same region as the substrate to be processed through which the beam can pass. In the electro-optical element, when the region through which the beam can pass is the same as that of the substrate to be processed, the laser beam is scanned while the position of the substrate to be processed and the electro-optical element is aligned and the positions are fixed. In this case, the electric signal input to the electro-optical element is one time in one thin film processing.

  Further, in order to reduce the size of the manufacturing apparatus, the electro-optic element may have an elongated rectangular shape that can pass or reflect at least a rectangular beam. For example, when an elongated DMD is used, the number of micromirrors that control the angle of reflection can be reduced, so that the modulation speed can be increased. Further, when an electro-optic element using an elongated liquid crystal is used, the same effect can be obtained because the number of scanning lines and signal lines is reduced and the driving speed can be increased. In addition, when the electro-optic element is a long and narrow rectangle, the number of times of changing the electric signal input to the electro-optic element in one thin film processing is plural. The thin film is continuously processed by sequentially changing the electric signal input to the electro-optical element so as to synchronize with the scanning of the rectangular beam.

Further, the spot shape of the laser beam irradiated on the irradiation surface is preferably rectangular or linear, and specifically, a rectangular shape having a short side of 1 mm to 5 mm and a long side of 10 mm to 50 mm. do it. When a laser beam spot with less aberration is desired, a square of 5 mm × 5 mm to 50 mm × 50 mm may be used. In the case of using a large-area substrate, the long side of the laser beam spot is preferably set to 20 cm to 100 cm in order to shorten the processing time. Further, a plurality of laser oscillators and optical systems shown in FIG. 9 may be provided to process a large area substrate in a short time. Specifically, a plurality of electro-optical elements may be installed above the substrate stage, and a laser beam may be emitted from a corresponding laser oscillator to share the processing area of one substrate. Furthermore, the area per shot may be set to the above-described size, and the electro-optical element may be controlled so that a laser beam having a complicated spot shape is irradiated therein. For example, a laser beam having a spot shape similar to the wiring shape can be irradiated.

Furthermore, a laser beam having a complicated spot shape may be used by superimposing rectangular or linear laser beams.

Further, instead of the stage for holding the substrate, the substrate may be moved by a method of blowing a gas to float the substrate 100. 590mm x 670mm, 600mm x 720mm, 650mm x 830mm are used on the production line as large area substrate sizes, and in the future, 680mm x 880mm, 730mm x 920mm, or larger sizes will be used. It is estimated that In the case of using a glass substrate having a side exceeding 1 m, it is preferable to move the substrate by a transport method that can reduce bending due to its own weight, for example, a method of blowing a gas to float the substrate.

Further, a holder for holding a standing substrate may be used instead of the stage for holding the substrate placed horizontally. By irradiating the laser beam while standing the substrate, the scattered matter can be removed from the substrate.

Further, a plurality of optical systems may be arranged on the optical path between the laser oscillator 1003 and the substrate 100 to perform further fine processing. Typically, the area and position of the laser beam can be finely processed by performing reduction projection using a stepper method having an electro-optic element larger than the substrate and a reduction optical system. Further, it is possible to perform the same magnification projection using the mirror projection method.

Moreover, it is preferable to install a position alignment means that is electrically connected to the control device. The alignment of the irradiation position can be performed with high accuracy by installing an image sensor such as a CCD camera and performing laser irradiation based on data obtained from the image sensor. In addition, a position marker can be formed by irradiating a laser beam to a desired position with this manufacturing apparatus.

In addition, when dust is generated by laser beam irradiation, it is preferable to further install a blow unit or a dust vacuum unit in the manufacturing apparatus for preventing the dust from adhering to the surface of the substrate to be processed. By simultaneously blowing or vacuuming the dust while irradiating the laser beam, the dust can be prevented from adhering to the substrate surface.

Note that FIG. 9 is an example, and the positional relationship between the optical systems and electro-optical elements disposed in the optical path of the laser beam is not particularly limited. For example, if the laser oscillator 1003 is disposed above the substrate 100 and the laser beam emitted from the laser oscillator 1003 is disposed in a direction perpendicular to the substrate surface, the reflection mirror may not be used. Each optical system may use a condensing lens, a beam expander, a homogenizer, or a polarizer, or a combination thereof. Moreover, you may combine a slit as each optical system.

By irradiating the irradiation region of the laser beam on the surface to be irradiated two-dimensionally and appropriately with the laser beam or the substrate, it is possible to irradiate a wide area of the substrate. Here, scanning is performed by a moving means (not shown) that moves the substrate stage 1009 holding the substrate in the XY directions.

In addition, the control device 1016 is preferably interlocked so as to be able to control a moving unit that moves the substrate stage 1009 in the XY directions. Further, the control device 1016 is preferably interlocked so that the laser oscillator 1003 can also be controlled. Furthermore, the control device 1016 is preferably linked to a position alignment mechanism for recognizing a position marker.

  FIG. 2A shows a top view of a part of the electro-optical element 1008 for irradiating the laser beam 105 as shown in FIG. Here, a mode in which the electro-optical element 1008 functions as an optical shutter is shown. In the electro-optical element 1008 shown in FIG. 2A, a laser beam light-shielding region 116a and a laser beam transmission region 116b are provided.

The light absorption layer 103 is selectively irradiated with the laser beam 105 using the electro-optical element 1008. The laser beam 105 has an energy density sufficient for gas emission in the light absorption layer 103 and sublimation or evaporation of the light absorption layer, typically within an energy density range of 1 μJ / cm ^{2 to} 100 J / cm ^2. be able to. A laser beam 105 having a sufficiently high energy density is absorbed by the light absorption layer 103. At this time, the light absorption layer 103 is locally and rapidly heated by the energy of the absorbed laser beam and sublimates or evaporates. The light absorption layer 104 is physically dissociated and scattered by the volume expansion accompanying the sublimation or evaporation. Through the above steps, the etched light absorption layer 113 can be formed over the second layer 102 as illustrated in FIG.

  As a result, as shown in FIG. 1B, part of the light absorption layer irradiated with the laser beam is removed by sublimation or evaporation of the light absorption layer 103. A top view of FIG. 1B is shown in FIG.

  Irradiation with the laser beam 105 can be performed under atmospheric pressure or reduced pressure. When the process is performed under reduced pressure, the scattered matter that is generated when the light absorption layer 103 is removed can be easily collected. For this reason, it is possible to prevent the scattered matter from remaining on the substrate.

  Furthermore, the light absorption layer 103 may be irradiated with a laser beam while the substrate 100 is heated. Also in this case, the light absorption layer 103 can be easily removed.

  Through the above steps, a mask can be selectively formed on the substrate by using part of the light absorption layer by irradiating the light absorption layer with a laser beam without using a photolithography step.

  Next, as shown in FIG. 1C, the second layer 112 is formed by etching the second layer 102 using the etched light absorption layer 113 as a mask. As an etching method of the second layer 102, dry etching, wet etching, or the like can be used as appropriate. Note that a top view of FIG. 1C is shown in FIG.

  Next, as shown in FIG. 1D, the light absorption layer 113 may be etched to expose the second layer 112. A top view of FIG. 1D is shown in FIG.

  Through the above steps, the second layer 112 having a predetermined shape can be formed in a predetermined place.

  Through the above steps, a layer having an arbitrary shape can be selectively formed over the substrate without using a photomask and a resist. In addition, a semiconductor device can be manufactured at low cost.

(Embodiment 2)
In this embodiment mode, a process of forming a layer having a desired shape by a process different from that of Embodiment Mode 1 will be described with reference to FIGS. The present embodiment is different from the first embodiment in the process of removing the light absorption layer using a laser beam.

As shown in FIG. 3A, as in Embodiment Mode 1, the first layer 101 is formed over the substrate 100, the second layer 102 is formed over the first layer 101, and the second layer A light absorption layer 103 is formed over the layer 102.

  Next, using the laser irradiation apparatus described in Embodiment 1, the light absorption layer 103 is irradiated with the laser beam 105. FIG. 4A shows a top view of a part of the electro-optical element 1008 for irradiating the laser beam 105 as shown in FIG.

  As a result, as shown in FIG. 3B, a part of the light absorption layer irradiated with the laser beam is removed. Here, part of the light absorption layer 103 remains in the region irradiated with the laser beam 105. That is, in the cross-sectional structure of the light absorption layer 133, d1 <d2 and d1> 0, where d1 is the thickness of the region 133a irradiated with the laser beam and d2 is the thickness of the region 133b not irradiated with the laser beam. is there.

  Therefore, a top view of FIG. 3B is shown in FIG. 4B, but unlike the first embodiment, the second layer 102 is not exposed, and only the light absorption layer 133 is exposed.

  Next, as illustrated in FIG. 3C, the light absorption layer 133 and the second layer 102 are etched using the thick region 133 b of the light absorption layer 113 as a mask, as in Embodiment Mode 1. As a result, a stack of the second layer 112 and the light absorption layer 113 can be formed. Note that a top view of FIG. 3C is shown in FIG. A top view of FIG. 3D is shown in FIG.

  Further, as in Embodiment Mode 1, as shown in FIG. 3D, the light absorption layer 113 may be etched to expose the second layer 112. A top view of FIG. 3D is shown in FIG.

  Through the above steps, a layer having an arbitrary shape can be selectively formed over the substrate without using a photomask and a resist. In addition, a semiconductor device can be manufactured at low cost.

(Embodiment 3)
In this embodiment mode, an etching process applicable in Embodiment Mode 1 or 2 will be described with reference to FIGS. Note that although the first embodiment is described here, the present invention can be applied to the second embodiment as appropriate.

As shown in FIG. 5A, as in Embodiment Mode 1, the first layer 101 is formed over the substrate 100, the second layer 102 is formed over the first layer 101, and the second layer A light absorption layer 103 is formed over the layer 102.

  Next, the light absorption layer 103 is irradiated with a laser beam 105.

  As a result, as shown in FIG. 5B, the light absorption layer irradiated with the laser beam 105 is removed, and the light absorption layer 113 functioning as a mask can be formed.

  Next, as shown in FIG. 5C, the second layer 102 is etched using the etched light absorption layer 113 as a mask. Here, as an etching method of the second layer 102, wet etching is performed. Further, the difference in etching rate between the light absorption layer 113 and the second layer 102 is large, and it is preferable that the etching rate of the second layer 102 is typically high. The second layer 102 is selectively isotropically etched. As a result, the light absorption layer 113 can be formed over the second layer 142 whose side surfaces are inclined and the second layer 142.

  Further, similarly to Embodiment Mode 1, as shown in FIG. 5D, the light absorption layer 113 may be etched to form a second layer 142 single layer.

  Through the above steps, a layer whose side surface is inclined can be formed. By using such a layer as a semiconductor layer of a top gate thin film transistor or a gate electrode of a thin film transistor or an inverted staggered thin film transistor, the coverage of the semiconductor layer or the gate insulating film formed over the gate electrode can be increased. As a result, leakage current of the semiconductor layer and the gate electrode can be reduced, and a highly reliable semiconductor device can be manufactured.

(Embodiment 4)
In this embodiment, a method for manufacturing a semiconductor element using Embodiment 1 will be described with reference to FIGS. Although this embodiment mode is described using Embodiment Mode 1, Embodiment Mode 2 or 3 can also be used.

  Here, an inverted staggered thin film transistor is used as a semiconductor element. Note that not only the inverted staggered thin film transistor but also a semiconductor element such as a forward staggered thin film transistor, a coplanar thin film transistor, a top gate thin film transistor, a diode, or a MOS transistor can be manufactured.

  As shown in FIG. 6A, a first layer 101 which functions as a base film, a second layer 102 which forms a gate electrode later, and a light absorption layer 103 are formed over a substrate 100.

  Here, a glass substrate is used as the substrate 100. A silicon oxynitride layer having a thickness of 50 to 200 nm is formed as the first layer 101 by a plasma CVD method, and a tungsten layer having a thickness of 50 to 500 nm, preferably 100 to 200 nm, is formed as a second layer 102 by a sputtering method. A layer is formed, and a chromium layer having a thickness of 50 to 300 nm, preferably 50 to 250 nm is formed as the light absorption layer 103 by a sputtering method.

  Next, the light absorption layer 103 is irradiated with the laser beam 105 by using the laser irradiation apparatus described in Embodiment 1. Here, the fourth harmonic (wavelength 266 nm) of YAG is used as the laser beam 105, and the laser beam irradiation conditions are an output of 2 W, a frequency of 15 kHz, a pulse width of 10 nanoseconds, and a maximum energy of one pulse of 130 μJ.

  By irradiating the light absorption layer 103 with the laser beam 105, as shown in FIG. 6B, a part of the light absorption layer 103 is removed and a light absorption layer 162 functioning as a mask is formed.

  Next, as illustrated in FIG. 6C, the second layer is formed by etching the second layer using the light absorption layer 162 functioning as a mask. Here, the second layer 102 is etched by dry etching.

  Next, as illustrated in FIG. 6D, the light absorption layer 162 is used as a mask, and the second layer 161 is wet-etched, so that the second layer 164 whose side surfaces are inclined is formed. Here, wet etching is preferably performed using an etchant that selectively etches the second layer 102. Thereafter, the light absorption layer 162 functioning as a mask is removed.

  Next, as illustrated in FIG. 6E, an insulating layer 165 that functions as a gate insulating film is formed over the second layer 164 that functions as a gate electrode, and a semiconductor layer 166 is formed thereover. A conductive semiconductor layer 167 is formed, and a light absorption layer 168 is formed thereover.

  As the semiconductor layer 166, an amorphous semiconductor, a semi-amorphous semiconductor in which an amorphous state and a crystalline state are mixed (also referred to as SAS), and crystal grains of 0.5 nm to 20 nm are observed in the amorphous semiconductor. A film having any state selected from a microcrystalline semiconductor and a crystalline semiconductor film which can be used can be used.

  The conductive semiconductor layer 167 is a semiconductor layer containing an acceptor element or a donor element such as phosphorus, arsenic, or boron.

  Here, as the insulating layer 165 functioning as a gate insulating film, a silicon oxynitride layer having a thickness of 10 to 50 nm is formed using a plasma CVD method, and an amorphous layer having a thickness of 50 to 150 nm is formed as a semiconductor layer 166 using a plasma CVD method. A silicon layer is formed, an amorphous silicon layer doped with phosphorus with a thickness of 50 to 150 nm is formed as the conductive semiconductor layer 167 using a plasma CVD method, and a sputtering method is used as the light absorption layer 168. Thus, a chromium layer having a thickness of 50 to 300 nm, preferably 50 to 250 nm is formed.

  Next, the light absorption layer 168 is irradiated with the laser beam 170 using the laser irradiation apparatus described in Embodiment 1. As a result, a light absorption layer 171 functioning as a mask is formed as shown in FIG.

  Next, the conductive semiconductor layer 167 and the semiconductor layer 166 are etched using the light absorption layer 171 as a mask. Here, the conductive semiconductor layer 167 and the semiconductor layer 166 are etched by dry etching. As a result, as shown in FIG. 7A, an etched semiconductor layer 174 and a conductive semiconductor layer 175 can be formed. Note that the semiconductor layer 174 and the conductive semiconductor layer 175 may be formed by a photolithography process.

  Next, the light absorption layer 171 is irradiated with the laser beam 178 using the laser irradiation apparatus described in Embodiment 1, so that part of the light absorption layer 171 is removed. As a result, a light absorption layer 179 functioning as a mask is formed as shown in FIG.

  Next, the semiconductor layer 174 and the conductive semiconductor layer 175 are etched using the light absorption layer 179 as a mask. As a result, as shown in FIG. 7C, the conductive semiconductor layer 182 that functions as a contact layer by dividing the conductive semiconductor layer 175 can be formed. At this time, the semiconductor layer 175 is also slightly etched. A semiconductor layer in which the channel portion is slightly etched is referred to as a semiconductor layer 181. Note that the semiconductor layer 181 functions as a channel region. Note that the semiconductor layer 181 and the conductive semiconductor layer 182 may be formed by a photolithography process.

  Next, as illustrated in FIG. 7D, after the light absorption layer 179 is removed, the insulating layer 165 functioning as a gate insulating film, the conductive semiconductor layer 182 functioning as a contact layer, and functioning as a channel region An insulating layer 183 is formed over the semiconductor layer 181 and the light absorption layer 179.

  Here, the insulating layer 183 is formed using polyimide by applying and baking the composition.

  Next, the insulating layer 183 and the light absorption layer 179 are irradiated with the laser beam 184 using the laser irradiation apparatus described in Embodiment 1. As a result, as shown in FIG. 7E, part of the insulating layer 183 and the light absorption layer 179 is removed to form an opening. In the opening, one or more of the light absorption layer 179, the conductive semiconductor layer 182, and the semiconductor layer 181 are exposed. Note that the opening formed in the insulating layer 183 may be formed using a photolithography process.

  Next, a wiring 186 is formed in the opening. The wiring 186 can be formed in a manner similar to that of the second layer 164 functioning as a gate electrode. Alternatively, a droplet of a prepared composition may be ejected from a minute hole to form a layer having a predetermined shape. Moreover, you may form using a printing method. Alternatively, after forming a conductive layer on a substrate by a CVD method, a PVD method, a coating method, or the like, the conductive layer may be selectively etched by a photolithography process. Here, a wiring mainly composed of silver is formed by a droplet discharge method.

  Through the above steps, a thin film transistor can be formed.

(Embodiment 5)
In this embodiment, a thin film transistor having a structure in which a wiring is in contact with a thin film transistor without an interlayer insulating film as compared with Embodiment 4 is described with reference to FIGS.

  8A, the first layer 101, the second layer 164 functioning as a gate electrode, and the insulating layer 165 functioning as a gate insulating film are formed over the substrate 100. The semiconductor layer 174, the conductive semiconductor layer 175, and the light absorption layer 176 are formed.

  Next, the conductive layer 191 and the light absorption layer 192 are formed over the semiconductor layer 174, the conductive semiconductor layer 175, and the light absorption layer 176. Here, an aluminum layer having a thickness of 500 to 1000 nm is formed as the conductive layer 191 by a sputtering method, and a chromium layer having a thickness of 5 to 50 nm, preferably 10 to 40 nm, is formed as the light absorption layer 192. Note that the light absorption layer 192 is not necessarily provided, and may be provided only when the conductive layer 191 is difficult to be removed by laser beam irradiation. By providing the light absorption layer 192, the light absorption layer 195 functioning as a mask can be easily formed.

  Next, the light absorption layer 192 is irradiated with the laser beam 194 using the laser irradiation apparatus described in Embodiment 1, and part of the light absorption layer 192 is removed, as illustrated in FIG. A light absorption layer 195 functioning as a mask is formed.

  Next, the conductive layer 191 and the light absorption layer 176 are etched using the light absorption layer 195 as a mask. Here, the conductive layer 191 and the light absorption layer 176 are etched by dry etching. As a result, a wiring 197 and a light absorption layer 198 are formed as shown in FIG.

  Next, as shown in FIG. 8D, the light absorption layer 198 functioning as a mask is removed. Note that the wiring 197 may be formed by a photolithography process.

  Next, the conductive semiconductor layer 175 and the semiconductor layer 174 are etched using the wiring 197 as a mask. As a result, as shown in FIG. 8E, a conductive semiconductor layer 199 functioning as a contact layer and a semiconductor layer 200 functioning as a channel region are formed.

  Through the above steps, the thin film transistor 1188 can be formed.

  In this embodiment, a liquid crystal display panel is formed as a semiconductor device. FIG. 10 is a cross-sectional view of one pixel of the liquid crystal display panel, which will be described below.

  As shown in FIG. 10A, the thin film transistor 1188 described in Embodiment 5 and the insulating layer 1190 which covers the thin film transistor 1188 are formed over the substrate 100. Here, the composition is applied by a coating method and baked to form an insulating layer 1190 formed of polyimide. Note that although the thin film transistor described in Embodiment 5 is used here as the thin film transistor 1188, the thin film transistor described in Embodiment 4, a coplanar thin film transistor, or a top gate thin film transistor can be used as appropriate.

Next, part of the insulating layer 1190 is irradiated with a laser beam to provide an opening, so that the insulating layer 1191 having the opening is formed. Thereafter, the oxide formed on the surface of the wiring 197 may be removed.

  Next, as illustrated in FIG. 10B, a conductive layer 1192 connected to the wiring 197 is formed over the opening and the surface of the insulating layer 1190. Note that the conductive layer 1192 functions as a pixel electrode. Here, the conductive layer 1192 is formed using ITO by the method described in Embodiment 1. By forming the light-transmitting conductive layer 1192, a transmissive light-emitting display panel can be manufactured later. Further, by forming a conductive layer having reflectivity such as Ag (silver), Au (gold), Cu (copper), W (tungsten), Al (aluminum) as the conductive layer 1192, a reflective light-emitting display is performed later. Panels can be made. Furthermore, a transflective display panel can be manufactured by forming the light-transmitting conductive layer and the reflective conductive layer for each pixel.

  Note that as illustrated in FIG. 10B, an opening can be formed so that the wiring 197 and the conductive layer 1192 are in contact with each other on the surface of the wiring 197.

  Further, as illustrated in FIG. 10C, the opening can be formed so that the conductive semiconductor layer 199 and the conductive semiconductor layer 199 are in contact with each other on the surface of the conductive semiconductor layer 199.

Through the above steps, an active matrix substrate can be formed.

  Next, an insulating film is formed by a printing method or a spin coating method, and rubbing is performed to form an alignment film 1193. Note that the alignment film 1193 can also be formed by an oblique evaporation method.

Next, in the counter substrate 1261 provided with the alignment film 1264, the second pixel electrode (counter electrode) 1263, and the coloring layer 1262, a closed loop sealant (illustrated) is formed in a region around the pixel portion by a droplet discharge method. Not). A filler may be mixed in the sealing material, and a color filter, a shielding film (black matrix), or the like may be formed on the counter substrate 1261.

Next, after the liquid crystal material is dropped inside the closed loop formed of the sealing material by a dispenser type (dropping type), the counter substrate and the active matrix substrate are bonded together in a vacuum, and ultraviolet curing is performed, thereby liquid crystal A liquid crystal layer 1265 filled with the material is formed. Note that as a method of forming the liquid crystal layer 1265, a dip method (pumping method) in which a liquid crystal material is injected using a capillary phenomenon after the counter substrate is bonded can be used instead of the dispenser method (dropping method).

After that, a wiring substrate, typically an FPC, is attached to the connection terminal portions of the scanning lines and signal lines through the connection conductive layer. Through the above process, a liquid crystal display panel can be formed.

Note that although a TN liquid crystal panel is described in this embodiment mode, the above process can be similarly applied to other types of liquid crystal panels. For example, the present embodiment can be applied to a horizontal electric field type liquid crystal panel in which an electric field is applied in parallel with a glass substrate to align liquid crystals. In addition, this embodiment mode can be applied to a VA (Vertical Alignment) liquid crystal panel.

11 and 12 show a pixel structure of a VA liquid crystal panel. FIG. 11 is a plan view, and FIG. 12 shows a cross-sectional structure corresponding to the cutting line I-J shown in the figure. The following description will be given with reference to both the drawings.

In this pixel structure, a single pixel has a plurality of pixel electrodes, and a TFT is connected to each pixel electrode. Each TFT is configured to be driven by a different gate signal. In other words, a multi-domain designed pixel has a configuration in which signals applied to individual pixel electrodes are controlled independently.

The pixel electrode layer 1624 is connected to the TFT 1628 through a wiring layer 1618 through an opening (contact hole) 1623. The pixel electrode layer 1626 is connected to the TFT 1629 through an opening (contact hole) 1627 through a wiring layer 1619. The gate wiring layer 1602 of the TFT 1628 and the gate electrode layer 1603 of the TFT 1629 are separated so that different gate signals can be given. On the other hand, the wiring layer 1616 functioning as a data line is used in common by the TFT 1628 and the TFT 1629.

The pixel electrode layer 1624 and the pixel electrode layer 1626 can be manufactured similarly to the above embodiment mode.

The pixel electrode layer 1624 and the pixel electrode layer 1626 have different shapes and are separated by a slit 1625. A pixel electrode layer 1626 is formed so as to surround the outside of the V-shaped pixel electrode layer 1624. The timing of the voltage applied to the pixel electrode layer 1624 and the pixel electrode layer 1626 is varied depending on the TFT 1628 and the TFT 1629, thereby controlling the alignment of the liquid crystal. A counter substrate 1601 is provided with a light-blocking film 1632, a coloring layer 1636, and a counter electrode layer 1640. In addition, a planarization film 1637 is formed between the coloring layer 1636 and the counter electrode layer 1640 to prevent alignment disorder of the liquid crystal. FIG. 13 shows a structure on the counter substrate side. The counter electrode layer 1640 is a common electrode between different pixels, but a slit 1641 is formed. By arranging the slits 1641 and the slits 1625 on the pixel electrode layer 1624 and pixel electrode layer 1626 side to alternately engage with each other, an oblique electric field can be effectively generated to control the alignment of the liquid crystal. Thereby, the direction in which the liquid crystal is aligned can be varied depending on the location, and the viewing angle is widened.

This embodiment can be freely combined with the above embodiment modes as appropriate.

Note that a protection circuit for preventing electrostatic breakdown, typically a diode or the like, may be provided between the connection terminal and the source wiring (gate wiring) or in the pixel portion. In this case, electrostatic breakdown can be prevented by manufacturing the TFT in the same process as the above-described TFT and connecting the gate wiring layer of the pixel portion and the drain or source wiring layer of the diode.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. Further, since a liquid crystal display device can be manufactured through a simplified process without using a complicated photolithography process, material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable liquid crystal display device can be manufactured with high yield.

  In this embodiment, a light-emitting display panel is formed as a semiconductor device. Further, FIG. 14 shows one pixel of the light emitting display panel, which will be described below.

  Similarly to Example 1, as illustrated in FIG. 14A, the thin film transistor 1188 described in Embodiment 5 and the insulating layer 1191 having an opening are formed over the substrate 100.

  Next, as shown in FIG. 14B, a first conductive layer 201 connected to the wiring 197 is formed as in the first embodiment. Note that the first conductive layer 201 functions as a pixel electrode.

  Next, as illustrated in FIG. 14C, an insulating layer 202 which covers an end portion of the first conductive layer 201 which functions as a pixel electrode is formed. Such an insulating layer can be formed by forming an insulating layer (not shown) over the insulating layer 1191 and the first conductive layer 201 and removing the insulating layer over the first conductive layer 201.

  Next, a layer 1203 having a light-emitting substance is formed on the exposed portion of the first conductive layer 201 and part of the insulating layer 202, and a second conductive layer 204 functioning as a pixel electrode is formed thereover. Through the above steps, the light-emitting element 1205 including the first conductive layer 201, the layer 1203 having a light-emitting substance, and the second conductive layer 204 can be formed.

  Here, the structure of the light-emitting element 1205 will be described.

  By forming a layer having a light emitting function using an organic compound (hereinafter, referred to as a light emitting layer 343) in the layer 1203 containing a light emitting substance, the light emitting element 1205 functions as an organic EL element.

Examples of the light-emitting organic compound include 9,10-di (2-naphthyl) anthracene (abbreviation: DNA) and 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA). ), 4,4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), coumarin 30, coumarin 6, coumarin 545, coumarin 545T, perylene, rubrene, periflanthene, 2,5,8,11-tetra (Tert-butyl) perylene (abbreviation: TBP), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyltetracene, 4- (dicyanomethylene) -2-methyl-6- [p- (dimethylamino) ) Styryl] -4H-pyran (abbreviation: DCM1), 4- (dicyanomethylene) -2-methyl-6- [2- Loridin-9-yl) ethenyl] -4H-pyran (abbreviation: DCM2), 4- (dicyanomethylene) -2,6-bis [p- (dimethylamino) styryl] -4H-pyran (abbreviation: BisDCM) and the like. Can be mentioned. In addition, bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ² ] (picolinato) iridium (abbreviation: FIrpic), bis {2- [3 ′, 5′-bis (trifluoromethyl) Phenyl] pyridinato-N, C ² } (picolinato) iridium (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), Tris (2-phenylpyridinato-N, C ² ) iridium (abbreviation: Ir (ppy)) _3), (acetylacetonato) bis (2-phenylpyridinato--N, ^{C 2)} iridium (abbreviation: _Ir (ppy) 2 (acac)), (acetylacetonato) bis [2- (2'-thienyl ) pyridinato -N, ^{C 3]} iridium _{(abbreviation: Ir (thp) 2 (acac} )), ( acetylacetonato) bis (2-phenylquinolinato--N, ^{C 2)} iridium ( _Aka: such as 2 (acac)): Ir ( pq) 2 (acac)), (Ir (btp acetylacetonato) bis [2- (2'-benzothienyl) pyridinato -N, ^{C 3]} iridium (abbreviation) A compound capable of emitting phosphorescence can also be used.

  As shown in FIG. 15A, a hole injection layer 341 formed of a hole injection material, a hole transport layer 342 formed of a hole transport material, and light emission on the first conductive layer 201. A light-emitting layer 343 formed of an organic compound, an electron transport layer 344 formed of an electron-transport material, a layer 318 containing a light-emitting material formed of an electron injection layer 345 formed of an electron-inject material, and The second light-emitting element 1205 may be formed using the second second conductive layer 204.

The hole transporting material includes phthalocyanine (abbreviation: H ₂ Pc), copper phthalocyanine (abbreviation: CuPc), vanadyl phthalocyanine (abbreviation: VOPc), and 4,4 ′, 4 ″ -tris (N, N-diphenyl). Amino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 1,3,5 -Tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl -4,4'-diamine (abbreviation: TPD), 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4'-bis {N- [ 4-di (m-tolyl) amino Phenyl-N-phenylamino} biphenyl (abbreviation: DNTPD), 4,4′-bis [N- (4-biphenylyl) -N-phenylamino] biphenyl (abbreviation: BBPB), 4,4 ′, 4 ″- Examples include tri (N-carbazolyl) triphenylamine (abbreviation: TCTA), but are not limited thereto. Among the above-mentioned compounds, aromatic amine compounds typified by TDATA, MTDATA, m-MTDAB, TPD, NPB, DNTPD, BBPB, TCTA, NPB and the like easily generate holes and are suitable as organic compounds. It is a compound group. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher.

As the hole injecting material, there is a material obtained by chemically doping a conductive polymer compound in addition to the above hole transporting material. Polyethylenedioxythiophene (abbreviation: PEDOT) doped with polystyrene sulfonic acid (abbreviation: PSS). ) And polyaniline (abbreviation: PAni) can also be used. Also effective are inorganic semiconductor thin films such as molybdenum oxide (MoO _x ), vanadium oxide (VO _x ), nickel oxide (NiO _x ), and ultra-thin films of inorganic insulators such as aluminum oxide (Al ₂ O ₃ ). .

Here, the electron transporting materials are tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h]. -Quinolinato) Beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), etc., a material comprising a metal complex having a quinoline skeleton or a benzoquinoline skeleton Can be used. In addition, bis [2- (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) A material such as a metal complex having an oxazole-based or thiazole-based ligand such as ₂ ) can also be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (P-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- ( 4-biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2, 4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and the like can be used. The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher.

Examples of the electron injection material include alkali metal halides such as LiF and CsF, alkaline earth halides such as CaF ₂ , and alkali metal oxides such as Li ₂ O in addition to the electron transport materials described above. Insulator ultrathin films are often used. In addition, alkali metal complexes such as lithium acetylacetonate (abbreviation: Li (acac) and 8-quinolinolato-lithium (abbreviation: Liq) are also effective. Furthermore, the above-described electron transporting materials, Mg, Li, Cs, and the like are also effective. It is also possible to use a material in which a metal having a small work function is mixed by co-evaporation or the like.

  15B, the first conductive layer 201, a hole transport layer 346 formed of an organic compound and an inorganic compound having an electron accepting property with respect to the organic compound, and a light-emitting organic compound are used. A light-emitting layer 343 formed, a light-emitting material layer 318 formed of an electron-transport layer 347 formed of an inorganic compound having an electron-donating property with respect to the light-emitting organic compound, and a second second conductive material The light-emitting element 1205 may be formed using the layer 204.

  The hole-transport layer 346 formed using a light-emitting organic compound and an inorganic compound having an electron-accepting property with respect to the light-emitting organic compound appropriately uses the above-described hole-transport organic compound as the organic compound. Form. The inorganic compound may be anything as long as it can easily receive electrons from an organic compound, and various metal oxides or metal nitrides can be used. Any one of Groups 4 to 12 of the periodic table can be used. These transition metal oxides are preferable because they easily exhibit electron accepting properties. Specific examples include titanium oxide, zirconium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, and zinc oxide. Among the metal oxides described above, any of the transition metal oxides in Groups 4 to 8 of the periodic table has a high electron accepting property and is a preferred group. Vanadium oxide, molybdenum oxide, tungsten oxide, and rhenium oxide are particularly preferable because they can be vacuum-deposited and are easy to handle.

  The electron-transport layer 347 formed using a light-emitting organic compound and an inorganic compound having an electron-donating property with respect to the light-emitting organic compound is formed using the above-described electron-transport organic compound as appropriate as the organic compound. In addition, the inorganic compound may be anything as long as it easily gives electrons from an organic compound, and various metal oxides or metal nitrides are possible. Alkali metal oxides, alkaline earth metal oxides, Rare earth metal oxides, alkali metal nitrides, alkaline earth metal nitrides, and rare earth metal nitrides are preferred because they easily exhibit electron donating properties. Specific examples include lithium oxide, strontium oxide, barium oxide, erbium oxide, lithium nitride, magnesium nitride, calcium nitride, yttrium nitride, and lanthanum nitride. In particular, lithium oxide, barium oxide, lithium nitride, magnesium nitride, and calcium nitride are preferable because they can be vacuum-deposited and are easy to handle.

  Since the electron transport layer 347 or the hole transport layer 346 formed using a light-emitting organic compound and an inorganic compound has excellent electron injection / transport characteristics, the first conductive layer 201 and the second second conductive layer are used. Both materials can be used with almost no work function limitations. In addition, the driving voltage can be reduced.

  In addition, the light-emitting element 1205 functions as an inorganic EL element because the layer 1203 containing a light-emitting substance has a layer having a light-emitting function using an inorganic compound (hereinafter referred to as a light-emitting layer 349). Inorganic EL elements are classified into a dispersion-type inorganic EL element and a thin-film inorganic EL element depending on the element structure. The former has a layer containing a light emitting material in which particles of the light emitting material are dispersed in a binder, and the latter has a layer containing a light emitting material made of a thin film of the light emitting material. The common point is that electrons accelerated by an electric field are required. Note that the obtained light emission mechanism includes donor-acceptor recombination light emission using a donor level and an acceptor level, and localized light emission using inner-shell electron transition of a metal ion. In many cases, dispersion-type inorganic EL emits donor-acceptor recombination light emission, and thin-film inorganic EL element emits localized light emission. The structure of the inorganic EL element is shown below.

  A light-emitting material that can be used in this embodiment mode includes a base material and an impurity element that serves as a light-emission center. By changing the impurity element to be contained, light emission of various colors can be obtained. As a method for manufacturing the light-emitting material, various methods such as a solid phase method and a liquid phase method (coprecipitation method) can be used. Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, method combining these methods with high temperature firing, liquid phase method such as freeze-drying method, etc. can be used.

  The solid phase method is a method in which a base material and an impurity element or a compound containing the impurity element are weighed, mixed in a mortar, heated and fired in an electric furnace, reacted, and the base material contains the impurity element. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. Although firing at a relatively high temperature is required, it is a simple method, so it has high productivity and is suitable for mass production.

  The liquid phase method (coprecipitation method) is a method in which a base material or a compound containing the base material and an impurity element or a compound containing the impurity element are reacted in a solution, dried, and then fired. The particles of the luminescent material are uniformly distributed, and the reaction can proceed even at a low firing temperature with a small particle size.

As a base material used for a light-emitting material of an inorganic EL element, sulfide, oxide, or nitride can be used. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used, such as calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

  As emission centers of localized emission, manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), praseodymium (Pr) or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation.

  On the other hand, a light-emitting material containing a first impurity element that forms a donor level and a second impurity element that forms an acceptor level can be used as the emission center of donor-acceptor recombination light emission. As the first impurity element, for example, fluorine (F), chlorine (Cl), aluminum (Al), or the like can be used. For example, copper (Cu), silver (Ag), or the like can be used as the second impurity element.

In the case where a light-emitting material for donor-acceptor recombination light emission is synthesized using a solid-phase method, a base material, a first impurity element or a compound containing the first impurity element, a second impurity element, or a second impurity element Each compound containing an impurity element is weighed and mixed in a mortar, and then heated and fired in an electric furnace. As the base material, the above-described base material can be used, and examples of the first impurity element or the compound containing the first impurity element include fluorine (F), chlorine (Cl), and aluminum sulfide (Al ₂ S). ₃ ) etc. can be used. In addition, as the second impurity element or the compound containing the second impurity element, for example, copper (Cu), silver (Ag), copper sulfide (Cu ₂ S), silver sulfide (Ag ₂ S), or the like is used. Can do. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state.

  In addition, as an impurity element in the case of using a solid phase reaction, a compound including a first impurity element and a second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. As the compound including the first impurity element and the second impurity element, for example, copper chloride (CuCl), silver chloride (AgCl), or the like can be used.

  Note that the concentration of these impurity elements may be 0.01 to 10 atom% with respect to the base material, and is preferably in the range of 0.05 to 5 atom%.

  FIG. 15C illustrates a cross section of an inorganic EL element in which a layer 1203 containing a light-emitting substance includes a first insulating layer, a light-emitting layer 349, and a second insulating layer 350.

  In the case of a thin-film inorganic EL, the light emitting layer 349 is a layer containing the above light emitting material, and is a physical vapor deposition method (such as a resistance heating vapor deposition method, a vacuum vapor deposition method such as an electron beam vapor deposition (EB vapor deposition) method, or a sputtering method ( PVD), metal organic chemical vapor deposition (CVD), chemical vapor deposition (CVD) such as hydride transport low pressure CVD, atomic epitaxy (ALE), or the like.

The first insulating layer 348 and the second insulating layer 350 are not particularly limited. However, the first insulating layer 348 and the second insulating layer 350 have high insulation resistance, preferably have a dense film quality, and preferably have a high dielectric constant. For example, silicon oxide (SiO ₂ ), yttrium oxide (Y ₂ O ₃ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), tantalum oxide (Ta ₂ O ₅ ), Barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), lead titanate (PbTiO ₃ ), silicon nitride (Si ₃ N ₄ ), zirconium oxide (ZrO ₂ ), etc., a mixed film thereof, or two or more kinds thereof Lamination can be used. The first insulating layer 348 and the second insulating layer 350 can be formed by sputtering, vapor deposition, CVD, or the like. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm. Note that the light-emitting element of this embodiment mode does not necessarily require hot electrons, and thus can be formed into a thin film and has an advantage that a driving voltage can be reduced. The film thickness is preferably 500 nm or less, more preferably 100 nm or less.

Note that although not illustrated, a buffer layer may be provided between the light-emitting layer 349 and the insulating layers 348 and 350 or between the light-emitting layer 349 and the first conductive layers 201 and 319. This buffer layer has a role of facilitating carrier injection and suppressing mixing of both layers. The buffer layer is not particularly limited. For example, ZnS, ZnSe, ZnTe, CdS, SrS, BaS, or the like, which is a base material of the light emitting layer, or CuS, Cu ₂ S, or LiF that is an alkali halide is used. CaF ₂ , BaF ₂ , MgF ₂ or the like can be used.

  In addition, as illustrated in FIG. 15D, the layer 1203 containing a light-emitting substance may include a light-emitting layer 349 and a first insulating layer 348. In this case, FIG. 15D illustrates a mode in which the first insulating layer 348 is provided between the second second conductive layer 204 and the light-emitting layer 349. Note that the first insulating layer 348 may be provided between the first conductive layer 201 and the light-emitting layer 349.

  Further, the layer 1203 containing a light-emitting substance may be formed using only the light-emitting layer 349. That is, the light-emitting element 1205 may be formed using the first conductive layer 201, the layer 1203 containing a light-emitting substance, and the second second conductive layer 204.

  In the case of a dispersion type inorganic EL, a particulate luminescent material is dispersed in a binder to form a layer containing a film-like luminescent substance. Process into particles. When particles having a desired size cannot be obtained sufficiently by the method for manufacturing a light emitting material, the particles may be processed into particles by pulverization or the like in a mortar or the like. The binder is a substance for fixing a granular light emitting material in a dispersed state and holding it in a shape as a layer containing a light emitting substance. The light emitting material is uniformly dispersed and fixed in the layer containing the light emitting substance by the binder.

  In the case of a dispersion-type inorganic EL, a method for forming a layer containing a light-emitting substance includes a droplet discharge method that can selectively form a layer containing a light-emitting substance, a printing method (such as screen printing or offset printing), and a spin coating method. An application method, a dipping method, a dispenser method, or the like can also be used. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm. In the layer including a light-emitting material and a light-emitting substance including a binder, the ratio of the light-emitting material may be 50 wt% or more and 80 wt% or less.

  The element in FIG. 15E includes a first conductive layer 201, a layer 1203 containing a light-emitting substance, and a second second conductive layer 204. The layer 1203 containing a light-emitting substance is a light-emitting material 352 and a binder 351. The light-emitting layer and the insulating layer 348 dispersed in each other. Note that although the insulating layer 348 is in contact with the second second conductive layer 204 in FIG. 15E, the insulating layer 348 may be in contact with the first conductive layer 201. The element may include an insulating layer in contact with each of the first conductive layer 201 and the second second conductive layer 204. Further, the element does not have to have an insulating layer in contact with the first conductive layer 201 and the second second conductive layer 204.

As a binder that can be used in this embodiment, an insulating material such as an organic material or an inorganic material can be used. Further, a mixed material of an organic material and an inorganic material may be used. As the organic insulating material, a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, or a resin such as polyethylene, polypropylene, polystyrene resin, silicone resin, epoxy resin, or vinylidene fluoride can be used. Alternatively, a heat-resistant polymer such as aromatic polyamide, polybenzimidazole, or siloxane resin may be used. Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent. Moreover, resin materials such as vinyl resins such as polyvinyl alcohol and polyvinyl butyral, phenol resins, novolac resins, acrylic resins, melamine resins, urethane resins, and oxazole resins (polybenzoxazole) may be used. Moreover, a photocuring type etc. can be used. The dielectric constant can be adjusted by appropriately mixing fine particles of high dielectric constant such as barium titanate (BaTiO ₃ ) and strontium titanate (SrTiO ₃ ) with these resins.

Examples of the inorganic insulating material used for the binder include silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon containing oxygen and nitrogen, aluminum nitride (AlN), aluminum containing oxygen and nitrogen, or aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), BaTiO ₃ , SrTiO ₃ , lead titanate (PbTiO ₃ ), potassium niobate (KNbO ₃ ), lead niobate (PbNbO ₃ ), tantalum oxide (Ta ₂ O ₅ ), A material selected from substances including barium tantalate (BaTa ₂ O ₆ ), lithium tantalate (LiTaO ₃ ), yttrium oxide (Y ₂ O ₃ ), zirconium oxide (ZrO ₂ ), ZnS and other inorganic insulating materials. Can be formed. By including an inorganic material having a high dielectric constant in the organic material (by addition or the like), the dielectric constant of the layer containing the light emitting material including the light emitting material and the binder can be further controlled, and the dielectric constant can be further increased. Can do.

  In the manufacturing process, the light-emitting material is dispersed in a solution containing a binder, but as a solvent of the solution containing the binder that can be used in this embodiment mode, a method of forming a light-emitting layer by dissolving the binder material (various wet types A solvent capable of producing a solution having a viscosity suitable for the process) and a desired film thickness may be appropriately selected. For example, when a siloxane resin is used as a binder, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate (also referred to as PGMEA), 3-methoxy-3-methyl-1-butanol (also referred to as MMB) can be used. Etc. can be used.

  Inorganic EL light-emitting elements can emit light by applying a voltage between a pair of electrodes sandwiching a layer containing a light-emitting substance, but can operate in either DC driving or AC driving.

Here, as a light-emitting element that displays red, an ITO layer containing silicon oxide with a thickness of 125 nm is formed as the first conductive layer 201 functioning as the first pixel electrode. As the layer 1203 containing a light-emitting substance, DNTPD is 50 nm, NPB is 10 nm, bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (acetylacetonato) (abbreviation: Ir (Fdpq) ₂ (acac) ) 30nm NPB of which is added, the Alq ₃ 30nm, formed by 30nm of Alq _3, and LiF was 1nm laminated. An Al layer having a thickness of 200 nm is formed as the second conductive layer 1204 functioning as the second pixel electrode.

As a light-emitting element that displays green, an ITO layer containing silicon oxide with a thickness of 125 nm is formed as the first conductive layer 201 functioning as the first pixel electrode. Further, as the layer 1203 including a light-emitting substance, a 50 nm, 10 nm and NPB, coumarin 545T (C545T) 40 nm of Alq ₃ that is added to form a Alq ₃ 30 nm, and LiF was 1nm laminated DNTPD. An Al layer having a thickness of 200 nm is formed as the second conductive layer 1204 functioning as the second pixel electrode.

As a light-emitting element that displays blue, an ITO layer containing silicon oxide with a thickness of 125 nm is formed as the first conductive layer 201 functioning as the first pixel electrode. Further, as the layer 1203 containing a light-emitting substance, 9- [4- (N) to which DNTPD is added to 50 nm, NPB is added to 10 nm, and 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP) is added. -Carbazolyl)] phenyl-10-phenylanthracene (abbreviation: CzPA :) 30 nm, Alq ₃ 30 nm, and LiF 1 nm. An Al layer having a thickness of 200 nm is formed as the second conductive layer 1204 functioning as the second pixel electrode.

  Next, a protective film is preferably formed over the second conductive layer 204.

After that, a wiring substrate, typically an FPC, is attached to the connection terminal portions of the scanning lines and signal lines through the connection conductive layer. Through the above steps, a light-emitting display panel can be formed.

Note that a protection circuit for preventing electrostatic breakdown, typically a diode or the like, may be provided between the connection terminal and the source wiring (gate wiring) or in the pixel portion.

  Here, in the light-emitting display panel having the light-emitting elements shown in FIGS. 15A and 15B, the case where radiation is emitted to the substrate 100 side, that is, the case where downward emission is performed will be described with reference to FIG. In this case, a conductive layer 484 having a light-transmitting property, a layer 485 containing a light-emitting substance, and a conductive layer 486 having a light-blocking property or a reflective property are sequentially stacked in contact with the wiring 197 so as to be electrically connected to the thin film transistor 1188. The The substrate 100 through which light is transmitted needs to be transparent to at least light in the visible region.

  Next, the case where radiation is performed on the side opposite to the substrate 100, that is, the case where upward radiation is performed will be described with reference to FIG. The thin film transistor 1188 can be formed in a manner similar to that of the thin film transistor described above. A wiring 197 electrically connected to the thin film transistor 1188 is in contact with and electrically connected to the conductive layer 463 having a light-blocking property or a reflective property. A conductive layer 463 having a light-blocking property or a reflective property, a layer 464 containing a light-emitting substance, and a conductive layer 465 having a light-transmitting property are sequentially stacked. The conductive layer 463 is a light-blocking or reflective metal layer, and reflects light emitted from the light-emitting element to the upper surface of the arrow. Note that a light-transmitting conductive layer may be formed over the light-blocking or reflective conductive layer 463. Since light emitted from the light-emitting element is emitted through the light-transmitting conductive layer 465, the light-transmitting conductive layer 465 is formed using a light-transmitting material at least in the visible region.

  Next, the case where light is emitted to both the substrate 100 side and the opposite side, that is, the case where both are emitted will be described with reference to FIG. A conductive layer 472 having a first light-transmitting property is electrically connected to the wiring 197 that is electrically connected to the semiconductor layer of the thin film transistor 1188. A conductive layer 472 having a first light-transmitting property, a layer 473 containing a light-emitting substance, and a conductive layer 474 having a second light-transmitting property are sequentially stacked. At this time, when both the first light-transmitting conductive layer 472 and the second light-transmitting conductive layer 474 are formed with a light-transmitting material or a thickness capable of transmitting light at least in the visible region. Both radiation is realized. In this case, the insulating layer that transmits light and the substrate 100 also need to have a light-transmitting property with respect to at least light in the visible region.

  Here, a pixel circuit of a light-emitting display panel having the light-emitting elements shown in FIGS. 15A and 15B and an operation configuration thereof will be described with reference to FIGS. There are two types of operation configurations of the light-emitting display panel, in which a video signal input to a pixel is defined by voltage and a current is defined by current in a display device in which a video signal is digital. There are two types of video signals defined by voltage, one having a constant voltage applied to the light emitting element (CVCV) and one having a constant current applied to the light emitting element (CVCC). In addition, a video signal is defined by current, there are a constant voltage applied to the light emitting element (CCCV) and a constant current applied to the light emitting element (CCCC). In this embodiment, a pixel that performs a CVCV operation will be described with reference to FIGS. Further, a pixel that performs the CVCC operation will be described with reference to FIG.

  In the pixel shown in FIGS. 17A and 17B, a signal line 3710 and a power supply line 3711 are arranged in the column direction, and a scanning line 3714 is arranged in the row direction. In addition, the pixel includes a switching TFT 3701, a driving TFT 3703, a capacitor element 3702, and a light emitting element 3705.

  Note that the switching TFT 3701 and the driving TFT 3703 operate in a linear region when turned on. The driving TFT 3703 has a role of controlling whether or not a voltage is applied to the light emitting element 3705. Both TFTs preferably have the same conductivity type in terms of manufacturing process. The driving TFT 3703 may be a depletion type TFT as well as an enhancement type. The ratio (W / L) of the channel width W to the channel length L (W / L) of the driving TFT 3703 is preferably 1 to 1000 depending on the mobility of the TFT. The larger the W / L, the better the electrical characteristics of the TFT.

  In the pixel shown in FIGS. 17A and 17B, the switching TFT 3701 controls input of a video signal to the pixel. When the switching TFT 3701 is turned on, the video signal is input into the pixel. Then, the voltage of the video signal is held in the capacitor 3702.

  In FIG. 17A, when the power supply line 3711 is Vss and the counter electrode of the light-emitting element 3705 is Vdd, the counter electrode of the light-emitting element is an anode and the electrode connected to the driving TFT 3703 is a cathode. In this case, luminance unevenness due to characteristic variations of the driving TFT 3703 can be suppressed.

  In FIG. 17A, when the power supply line 3711 is Vdd and the counter electrode of the light-emitting element 3705 is Vss, the counter electrode of the light-emitting element is a cathode and the electrode connected to the driving TFT 3703 is an anode. In this case, when a video signal having a voltage higher than Vdd is input to the signal line 3710, the voltage of the video signal is held in the capacitor 3702, and the driving TFT 3703 operates in a linear region. It is possible to improve.

  The pixel shown in FIG. 17B has the same pixel structure as that shown in FIG. 17A except that a TFT 3706 and a scanning line 3715 are added.

  The TFT 3706 is controlled to be turned on or off by a newly arranged scanning line 3715. When the TFT 3706 is turned on, the charge held in the capacitor 3702 is discharged, and the driving TFT 3703 is turned off. That is, the arrangement of the TFT 3706 can forcibly create a state in which no current flows through the light emitting element 3705. Therefore, the TFT 3706 can be called an erasing TFT. Therefore, the structure in FIG. 17B can improve the light emission duty ratio because the lighting period can be started simultaneously with or immediately after the start of the writing period without waiting for signal writing to all the pixels. Is possible.

  In the pixel having the above operation configuration, the current value of the light-emitting element 3705 can be determined by the driving TFT 3703 that operates in a linear region. With the above structure, variation in TFT characteristics can be suppressed, and luminance unevenness of a light-emitting element due to variation in TFT characteristics can be improved, so that a display device with improved image quality can be provided.

  Next, a pixel that performs the CVCC operation will be described with reference to FIG. In the pixel illustrated in FIG. 17C, a power supply line 3712 and a current control TFT 3704 are provided in the pixel configuration illustrated in FIG. Note that in the pixel illustrated in FIG. 17C, the gate electrode of the driving TFT 3703 may be connected to the power supply line 3712 arranged in the row direction with the power supply line 3712 arranged in the column direction.

  Note that the switching TFT 3701 operates in a linear region, and the driving TFT 3703 operates in a saturation region. The driving TFT 3703 has a role of controlling a current value flowing through the light emitting element 3705, and the current controlling TFT 3704 has a role of operating in a saturation region and controlling supply of current to the light emitting element 3705.

Note that the CVCC operation can also be performed in the pixels shown in FIGS. 17A and 17B. In addition, in the pixel having the operation structure illustrated in FIG. 17C, Vdd and Vss can be changed as appropriate depending on the direction in which the current of the light-emitting element flows, as in FIGS. 17A and 17B. .

  In the pixel having the above structure, since the current control TFT 3704 operates in a linear region, a slight change in Vgs of the current control TFT 3704 does not affect the current value of the light emitting element 3705. That is, the current value of the light emitting element 3705 can be determined by the driving TFT 3703 operating in the saturation region. With the above structure, it is possible to provide a display device in which luminance unevenness of a light-emitting element due to variation in TFT characteristics is improved and image quality is improved.

  In particular, in the case of forming a thin film transistor having an amorphous semiconductor or the like, it is preferable to increase the area of the semiconductor film of the driving TFT because the variation of the TFT can be reduced. In addition, the pixel shown in FIGS. 17A and 17B can increase the aperture ratio because the number of TFTs is small.

  Note that although a structure including the capacitor 3702 is shown, the present invention is not limited to this, and the capacitor 3702 is not provided in the case where the capacity for holding a video signal can be covered by a gate capacitor or the like. May be.

  In addition, when the semiconductor layer of the thin film transistor is formed using an amorphous semiconductor film, a threshold value is likely to shift. Therefore, a circuit for correcting the threshold value is preferably provided in or around the pixel.

  Such an active matrix light-emitting device is considered to be advantageous because it can be driven at a low voltage because a TFT is provided in each pixel when the pixel density is increased. On the other hand, a passive matrix light-emitting device can also be formed. A passive matrix light-emitting device has a high aperture ratio because a TFT is not provided for each pixel.

  In the display device of the present invention, the screen display driving method is not particularly limited. 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 display 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.

  As described above, various pixel circuits can be employed.

According to this embodiment, a component such as a wiring constituting the light emitting display panel can be formed in a desired shape. Further, since a light-emitting display panel can be manufactured through a simplified process without using a complicated photolithography process, material loss is small and cost reduction can be achieved. Thus, a high-performance and highly reliable light-emitting display device can be manufactured with high yield.

In this embodiment, a typical example of an electrophoretic display panel will be described with reference to FIGS. An electrophoretic element is a microcapsule in which a positive and negative charged black and white particle is confined between a first conductive layer and a second conductive layer. This is an element that performs display by causing a potential difference in the second conductive layer to move black and white particles between electrodes.

  Similarly to Example 1, as illustrated in FIG. 18, the thin film transistor 1188 described in Embodiment 5 and the insulating layer 1191 having an opening are formed over the substrate 100 so as to cover the thin film transistor 1188.

  Next, as in Example 1, a first conductive layer 1171 connected to the wiring 197 is formed. Note that the first conductive layer 1171 functions as a pixel electrode. Here, the first conductive layer 1171 is formed using aluminum by the method described in the above embodiment mode.

  In addition, a second conductive layer 1173 is formed over the substrate 1172. The second conductive layer 1173 is also preferably formed in parallel. Here, the second conductive layer 1173 is formed using ITO by the method described in the above embodiment mode.

  Next, the substrate 100 and the substrate 1172 are attached to each other with a sealant. At this time, the microcapsules 1170 are dispersed between the first conductive layer 1171 and the second conductive layer 1173, so that an electrophoretic element is formed between the substrate 100 and the substrate 1172. The substrate 100 and the substrate 1172 are attached to each other with a sealant so that the first conductive layer 1171 and the second conductive layer 1173 intersect with each other. The electrophoretic element includes a first conductive layer 1171, a microcapsule 1170, and a second conductive layer 1173. The microcapsule 1170 is fixed between the first conductive layer 1171 and the second conductive layer 1173 by a binder.

  Next, the structure of the microcapsule will be described with reference to FIG. As shown in FIGS. 19A and 19B, in the microcapsule 1170, a transparent dispersion medium 1176, charged black particles 1175a, and white particles 1175b are dispersed in a fine transparent container 1174. Instead of the black particles 1175a, blue particles, red particles, green particles, yellow particles, blue green particles, and red purple particles may be used. Further, as shown in FIGS. 19C and 19D, a microcapsule 1330 in which a colored dispersion medium 1333 and white particles 1332 are dispersed in a fine transparent container 1331 may be used. Note that the colored dispersion medium 1333 is colored in any one of black, blue, red, green, yellow, blue-green, and magenta. Further, by providing each pixel with microcapsules in which blue particles, red particles, and green particles are dispersed, color display can be performed. In addition, by providing microcapsules in which yellow particles, blue-green particles, and red-violet particles are dispersed, color display can be performed. Further, color display can be performed by arranging microcapsules having blue, red, and green dispersion media in one pixel. In addition, color display can be performed by arranging microcapsules having yellow, blue-green, and magenta dispersion media in one pixel.

  Next, a display method using an electrophoretic element will be described. Specifically, a display method of the microcapsule 1170 having two-color particles is described with reference to FIGS. Here, a microcapsule using white particles and black particles as two-color particles and having a transparent dispersion medium is shown. Note that particles of other colors may be used instead of the black particles of the two colors.

  In the microcapsule 1170, it is assumed that the black particles 1175a are positively charged and the white particles 1175b are negatively charged, and an electric field is applied to the first conductive layer 1171 and the second conductive layer 1173. Here, when an electric field is applied in the direction from the second conductive layer to the first conductive layer as indicated by an arrow, the black particles 1175a migrate to the second conductive layer 1173 side as shown in FIG. 19A. Then, the white particles 1175b migrate to the first conductive layer 1171 side. As a result, when the microcapsule is viewed from the first conductive layer 1171 side, it is observed as white, and when viewed from the second conductive layer 1173 side, it is observed as black.

  On the other hand, when an electric field is applied in the direction from the first conductive layer 1171 to the second conductive layer 1173 as indicated by an arrow, black particles 1175a are formed on the first conductive layer 1171 side as illustrated in FIG. The white particles 1175b migrate to the second conductive layer 1173 side. As a result, when the microcapsule is viewed from the first conductive layer 1171 side, it is observed as white, and when viewed from the second conductive layer 1173 side, it is observed as black.

  Next, a display method of the microcapsule 1330 including white particles and a colored dispersion medium is described. Here, an example in which the dispersion medium is colored in black is shown, but the same applies even when a dispersion medium colored in another color is used.

  In the microcapsule 1330, the white particles 1332 are negatively charged, and an electric field is applied to the first conductive layer 1171 and the second conductive layer 1173. Here, when an electric field is applied in the direction from the second conductive layer to the first conductive layer as indicated by an arrow, white particles 1175b are formed on the first conductive layer 1171 side as shown in FIG. 19C. Migrate. As a result, when the microcapsule is viewed from the first conductive layer 1171 side, it is observed as white, and when viewed from the second conductive layer 1173 side, it is observed as black.

  On the other hand, when an electric field is applied in the direction from the first conductive layer to the second conductive layer as indicated by an arrow, white particles 1175b are formed on the second conductive layer 1173 side as shown in FIG. As a result, when the microcapsule is viewed from the first conductive layer 1171 side, it is observed as white, and when viewed from the second conductive layer 1173 side, it is observed as black.

Here, the electrophoretic element has been described, but a display device using a twisting ball display method may be used instead. In the twisting ball display method, spherical particles that are separately painted in white and black are arranged between the first conductive layer and the second conductive layer, and a potential difference is generated between the first conductive layer and the second conductive layer. In this method, display is performed by controlling the orientation of the spherical particles.

  Further, instead of a thin film transistor, a MIM (Metal-Insulator-Metal), a diode, or the like can be used as a switching element.

  A display device having an electrophoretic element or a display device using a twisting ball display system maintains the same state as when an electric field is applied for a long time after the field effect transistor is removed. Thus, the display state can be maintained even when the power is turned off. For this reason, low power consumption is possible.

According to this embodiment, it is possible to form components such as wirings constituting the electrophoretic display panel in a desired shape. Further, since a semiconductor device having an electrophoretic element can be manufactured through a simplified process without using a complicated photolithography process, material loss is small and cost reduction can be achieved. Accordingly, a semiconductor device including a high-performance and highly reliable electrophoretic element can be manufactured with high yield.

  In the display panels (EL display panel, liquid crystal display panel, electrophoretic display panel) manufactured according to Embodiments 1 to 3, the semiconductor layer is formed of an amorphous semiconductor or semi-amorphous silicon (SAS), and the scanning line side An example in which a drive circuit is formed on a substrate is shown.

FIG. 20 shows a block diagram of a scanning line side driving circuit constituted by an n-channel TFT using SAS capable of obtaining a field effect mobility of 1 to 15 cm ² / V · sec.

  In FIG. 20, a block denoted by reference numeral 8500 corresponds to a pulse output circuit that outputs a sampling pulse for one stage, and the shift register includes n pulse output circuits. Reference numeral 8501 denotes a buffer circuit to which a pixel 8502 is connected.

  FIG. 21 shows a specific configuration of the pulse output circuit 8500, and a circuit is configured by n-channel TFTs 8601 to 8612. At this time, the size of the TFT may be determined in consideration of the operating characteristics of the n-channel TFT using SAS. For example, if the channel length is 8 μm, the channel width can be set in the range of 10 to 80 μm.

  Further, a specific structure of the buffer circuit 8501 is shown in FIG. Similarly, the buffer circuit includes n-channel TFTs 8620 to 8635. At this time, the size of the TFT may be determined in consideration of the operating characteristics of the n-channel TFT using SAS. For example, if the channel length is 10 μm, the channel width is set in the range of 10 to 1800 μm.

  In order to realize such a circuit, it is necessary to connect the TFTs by wiring.

As described above, a driver circuit can be incorporated in the display panel.

  Next, mounting of a driver circuit on the display panel described in the above embodiment will be described with reference to FIGS.

  As shown in FIG. 23A, a source line driver circuit 1402 and gate line driver circuits 1403a and 1403b are mounted around the pixel portion 1401. In FIG. 23A, as a source line driver circuit 1402 and gate line driver circuits 1403a and 1403b, a mounting method using a known anisotropic conductive adhesive and an anisotropic conductive film, a COG method, wire bonding The IC chip 1405 is mounted on the substrate 1400 by a method, a reflow process using a solder bump, or the like. Here, the COG method is used. Then, the IC chip and an external circuit are connected through the FPC 1406.

  Note that a part of the source line driver circuit 1402, for example, an analog switch may be formed over the substrate, and the other part may be separately mounted using an IC chip.

  As shown in FIG. 23B, when a TFT is formed using SAS or a crystalline semiconductor, the pixel portion 1401, gate line driver circuits 1403a and 1403b, and the like are formed over the substrate, and the source line driver circuit 1402 and the like are formed. It may be mounted as an IC chip separately. In FIG. 23B, an IC chip 1405 is mounted on a substrate 1400 as a source line driver circuit 1402 by a COG method. Then, the IC chip and an external circuit are connected through the FPC 1406.

  Note that a part of the source line driver circuit 1402, for example, an analog switch may be formed over the substrate, and the other part may be separately mounted using an IC chip.

  Further, as shown in FIG. 23C, the source line driver circuit 1402 and the like may be mounted by a TAB method instead of the COG method. Then, the IC chip and an external circuit are connected through the FPC 1406. Although the source line driver circuit is mounted by a TAB method in FIG. 23C, the gate line driver circuit may be mounted by a TAB method.

  When the IC chip is mounted by the TAB method, a pixel portion can be provided larger than the substrate, and a narrow frame can be achieved.

  The IC chip is formed using a silicon wafer, but an IC (hereinafter referred to as a driver IC) in which a circuit is formed on a glass substrate may be provided instead of the IC chip. Since an IC chip is taken out from a circular silicon wafer, the shape of the base substrate is limited. On the other hand, the driver IC has a mother substrate made of glass and has no restriction in shape, so that productivity can be improved. Therefore, the shape of the driver IC can be set freely. For example, when the length of the long side of the driver IC is 15 to 80 mm, the required number can be reduced as compared with the case where the IC chip is mounted. As a result, the number of connection terminals can be reduced, and the manufacturing yield can be improved.

  The driver IC can be formed using a crystalline semiconductor formed over a substrate, and the crystalline semiconductor is preferably formed by irradiation with a continuous wave laser beam. A semiconductor film obtained by irradiation with a continuous wave laser beam has few crystal defects and large crystal grains. As a result, a transistor having such a semiconductor film has favorable mobility and response speed, can be driven at high speed, and is suitable for a driver IC.

  Next, a module having the display panel shown in the above embodiment will be described with reference to FIG. FIG. 24 shows a module in which a display panel 9801 and a circuit board 9802 are combined. On the circuit board 9802, for example, a control circuit 9804, a signal dividing circuit 9805, and the like are formed. In addition, the display panel 9801 and the circuit board 9802 are connected by a connection wiring 9803. As the display panel 9801, a liquid crystal display panel, a light-emitting display panel, an electrophoretic display panel, or the like as described in Embodiments 1 to 3 can be used as appropriate.

  This display panel 9801 includes a pixel portion 9806 in which a light-emitting element is provided in each pixel, a scanning line driver circuit 9807, and a signal line driver circuit 9808 that supplies a video signal to a selected pixel. The configuration of the pixel portion 9806 is the same as in Embodiments 1 to 3. The scanning line driver circuit 9807 and the signal line driver circuit 9808 are a mounting method using an anisotropic conductive adhesive and an anisotropic conductive film, a COG method, a wire bonding method, a reflow process using a solder bump, and the like. By the method described above, a scanning line driver circuit 9807 and a signal line driver circuit 9808 formed with IC chips are mounted on a substrate.

  According to this embodiment, a module having a display panel can be formed with high yield.

  As an electronic device including the semiconductor device described in the above embodiment mode or a semiconductor device, a television device (also simply referred to as a television or a television receiver), a digital camera, a digital video camera, or a mobile phone device (also simply referred to as a mobile phone or a mobile phone) ), Portable information terminals such as PDAs, portable game machines, computer monitors, computers, sound reproduction apparatuses such as car audio, and image reproduction apparatuses equipped with recording media such as home game machines. A specific example will be described with reference to FIG.

  A portable information terminal illustrated in FIG. 25A includes a main body 9201, a display portion 9202, and the like. By applying what is described in the above embodiment to the display portion 9202, a portable information terminal can be provided at low cost.

  A digital video camera shown in FIG. 25B includes a display portion 9701, a display portion 9702, and the like. By applying the display portion 9701 to any of the above embodiments, a digital video camera can be provided at low cost.

  A portable terminal illustrated in FIG. 25C includes a main body 9101, a display portion 9102, and the like. By applying the display portion described in any of the above embodiments to the display portion 9102, a portable terminal can be provided at low cost.

  A portable television device shown in FIG. 25D includes a main body 9301, a display portion 9302, and the like. By applying the display portion described in any of the above embodiments to the display portion 9302, a portable television device can be provided at low cost. Such a television device can be widely applied from a small one mounted on a portable terminal such as a cellular phone to a medium-sized one that can be carried and a large one (for example, 40 inches or more). .

  A portable computer shown in FIG. 25E includes a main body 9401, a display portion 9402, and the like. By applying the display portion described in the above embodiment to the display portion 9402, a portable computer can be provided at low cost.

  A television set illustrated in FIG. 25F includes a main body 9601, a display portion 9602, and the like. A television device can be provided at low cost by applying the display portion 9602 to the display portion 9602.

  Here, the structure of the television device will be described with reference to FIG.

  FIG. 26 is a block diagram illustrating a main configuration of a television device. A tuner 9511 receives a video signal and an audio signal. The video signal includes a video detection circuit 9512, a video signal processing circuit 9513 that converts the signal output from the video signal into a color signal corresponding to each color of red, green, and blue, and converts the video signal into the input specifications of the driver IC. Is processed by a control circuit 9514. The control circuit 9514 outputs signals to the scan line driver circuit 9516 and the signal line driver circuit 9517 of the display panel 9515, respectively. In the case of digital driving, a signal dividing circuit 9518 may be provided on the signal line side so that an input digital signal is divided into m pieces and supplied.

  Of the signals received by the tuner 9511, the audio signal is sent to the audio detection circuit 9521, and the output is supplied to the speaker 9523 through the audio signal processing circuit 9522. The control circuit 9524 receives control information on the receiving station (reception frequency) and volume from the input unit 9525 and sends a signal to the tuner 9511 and the audio signal processing circuit 9522.

  This television device includes the display panel 9515, whereby low power consumption of the television device can be achieved. In addition, a television device can be manufactured.

  Note that the present invention is not limited to a television receiver, and is applicable to various uses as a display medium of a particularly large area such as a monitor of a personal computer, an information display board in a railway station or airport, an advertisement display board in a street, etc. can do.

8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are top views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are top views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. It is a perspective view explaining the laser irradiation apparatus applicable to this invention. It is sectional drawing explaining the manufacturing method of the semiconductor device of this invention of this invention. It is a top view illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are top views illustrating a method for manufacturing a semiconductor device of the present invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. It is a figure explaining the cross-section of the light emitting element which can be applied to this invention. It is a figure explaining the cross-section of the light emitting element which can be applied to this invention. It is a figure explaining the equivalent circuit of the light emitting element which can be applied to this invention. 8A to 8D are cross-sectional views illustrating a method for manufacturing a semiconductor device of the present invention. It is a figure explaining the cross-sectional structure of the electrophoretic element which can be applied to this invention. 4A and 4B each illustrate a circuit structure in the case where a scan line side driver circuit is formed using TFTs in a display panel of the present invention; 4A and 4B illustrate a circuit structure in the case where a scan line driver circuit is formed using TFTs in a display panel of the present invention (shift register circuit). 4A and 4B illustrate a circuit configuration in the case where a scan line side driver circuit is formed using TFTs in a display panel of the present invention (buffer circuit). It is a top view illustrating a semiconductor device of the present invention. It is a top view illustrating a semiconductor device of the present invention. FIG. 11 is a perspective view illustrating an electronic device using the semiconductor device of the invention. FIG. 11 illustrates an electronic device using a semiconductor device of the present invention.

Claims (10)

Forming a first layer on the substrate, forming a light absorption layer on the first layer,
Selectively irradiating the light absorbing layer with a laser beam;
Removing a part of the light absorption layer irradiated with the laser beam to expose a part of the first layer;
A method for manufacturing a semiconductor device, wherein the exposed first layer is etched to form a second layer. Forming a first layer on the substrate, forming a light absorption layer on the first layer,
Selectively irradiating the light absorbing layer with a laser beam;
Removing a part of the light absorption layer irradiated with the laser beam to form a light absorption layer having a first thickness and a light absorption layer having a second thickness smaller than the first thickness;
A method for manufacturing a semiconductor device, wherein the second layer is formed by etching the light absorption layer and the first layer using the light absorption layer having the first thickness as a mask. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the second layer is a stacked layer of an etched light absorption layer and the first layer.   4. The method for manufacturing a semiconductor device according to claim 1, wherein the etching is wet etching. 5. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the etching is dry etching. 5.   6. The method for manufacturing a semiconductor device according to claim 1, wherein after the second layer is formed, the light absorption layer of the second layer is removed.   7. The method for manufacturing a semiconductor device according to claim 1, wherein the laser beam has a rectangular shape.   The method for manufacturing a semiconductor device according to claim 1, wherein the laser beam is linear.   9. The method for manufacturing a semiconductor device according to claim 1, wherein the laser beam is emitted from a laser irradiation apparatus.   10. The method for manufacturing a semiconductor device according to claim 1, wherein the laser irradiation apparatus includes an electro-optic element, and the electro-optic element is connected to a control device.

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