JP2016148744A - Light emitting panel, display module, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel light emitting panel having excellent convenience or reliability, a novel display module having excellent convenience or reliability, and a novel display device having excellent convenience or reliability.SOLUTION: This invention employs a configuration comprising a segment circuit that is supplied with a control signal and a signal and has the function of supplying predetermined power, and a light emitting element that is supplied with predetermined power.SELECTED DRAWING: Figure 1

Description

One embodiment of the present invention relates to a light-emitting panel, a display module, or a display device.

Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, as a technical field of one embodiment of the present invention disclosed more specifically in this specification, a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof, Can be cited as an example.

A technique (local dimming method) for displaying an image by dividing the display area of a liquid crystal display device into a plurality of areas and controlling the brightness of the backlight for each of the divided display areas is known. When the local dimming method is used, an image in which a bright part and a dark part are arranged in different areas can be displayed with high contrast.

For example, the resolution is increased using super-resolution processing. Then, after super-resolution processing, a method of driving a liquid crystal display device that performs display by controlling the luminance of the backlight using local dimming is used (Patent Document 1).

JP 2010-164953 A

An object of one embodiment of the present invention is to provide a novel light-emitting panel that is highly convenient or reliable. Another object is to provide a novel display module that is highly convenient or reliable. Another object is to provide a novel display device that is highly convenient or reliable. Another object is to provide a novel light-emitting panel, a novel display module, a novel display device, or a novel semiconductor device.

Note that the description of these problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not have to solve all of these problems. Issues other than these will be apparent from the description of the specification, drawings, claims, etc., and other issues can be extracted from the descriptions of the specification, drawings, claims, etc. It is.

One embodiment of the present invention includes a first connection portion, a segment circuit electrically connected to the first connection portion, a light-emitting element electrically connected to the first connection portion, and a segment circuit. A light-emitting panel having a first base material provided and a second base material on which a light-emitting element is disposed.

The segment circuit is electrically connected to the first power supply line, electrically connected to the selection line, and electrically connected to the signal line.

The selection line has a function of supplying a selection signal, and the signal line has a function of supplying a control signal.

The segment circuit has a function of supplying power to the first connection unit, and has a function of controlling power based on the selection signal and the control signal.

The light emitting element includes a first electrode and a second electrode, the first electrode is electrically connected to the first connection portion, and the second electrode is electrically connected to the second power supply line. The first electrode is supplied with power. The second power supply line supplies a potential different from that of the first power supply line.

Another embodiment of the present invention is the above light-emitting panel including a plurality of segment circuits.

The plurality of segment circuits are arranged in a matrix on the first base material, the selection lines are electrically connected to the plurality of segment circuits arranged in the row direction, and the signal lines are arranged in the row direction. It is electrically connected to a plurality of segment circuits arranged in the intersecting column direction.

The light-emitting panel of one embodiment of the present invention includes a segment circuit which is supplied with a control signal and a signal and has a function of supplying power, and a light-emitting element to which power is supplied. Thereby, the electric power determined based on the control signal and the signal can be supplied to the light emitting element. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

In one embodiment of the present invention, the second base material includes a region overlapping with the first base material, the second base material is disposed between the light-emitting element and the first base material, The base material of 2 is an above-mentioned luminescent panel provided with an opening, and the 1st connection part contains the 1st wiring arranged in the opening.

Another embodiment of the present invention is the above light-emitting panel including the second connection portion that is electrically connected to the first power supply line. The segment circuit is electrically connected to the second connection portion, and the first power supply line and the second power supply line are disposed on the second base material.

In the light-emitting panel of one embodiment of the present invention, the first base material on which the segment circuit is disposed and the second base material on which the light-emitting element electrically connected to the segment circuit is stacked The segment circuit and the light emitting element are configured to include a connection portion that is electrically connected. Thereby, an external shape can be made small. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

In one embodiment of the present invention, the segment circuit includes a first transistor in which a gate is electrically connected to a selection line, a first electrode is electrically connected to a signal line, and a gate is the first transistor. The second transistor is electrically connected to the second electrode, the first electrode is electrically connected to the first connection portion, and the second electrode is electrically connected to the first power supply line. And a capacitor element in which the first electrode is electrically connected to the gate of the second transistor, and the second electrode is electrically connected to the second electrode of the second transistor. It is a light emitting panel.

Another embodiment of the present invention is the above light-emitting panel in which the segment circuit includes a plurality of transistors, and the plurality of transistors includes a semiconductor film that can be formed in the same process.

Another embodiment of the present invention is the above light-emitting panel, in which the segment circuit includes a plurality of transistors, and the plurality of transistors includes an oxide semiconductor film that can be formed in the same step.

The light-emitting panel of one embodiment of the present invention includes a switch that can be turned on or off based on a selection signal, and a capacitor that holds electric charge based on a control signal supplied in the conductive state in the non-conductive state. An element and a transistor that supplies electric power based on a voltage held by the capacitor are included. Accordingly, the light emitting element can be driven with power based on the control signal supplied during the period in which the selection signal is supplied. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

Another embodiment of the present invention is a display module including the above light-emitting panel and a display panel including a region overlapping with the light-emitting panel. The display panel includes a plurality of pixels in a region overlapping with one light emitting element.

The light-emitting panel of one embodiment of the present invention includes a plurality of pixels in a region overlapping with a light-emitting element that is electrically connected to one segment circuit. Thereby, an image can be displayed using the light whose luminance is adjusted for each segment. As a result, a novel display module that is highly convenient or reliable can be provided.

Another embodiment of the present invention includes the above display module and a driver portion which is electrically connected to the display module. The driving unit has a function of supplying an image signal, a selection signal, and a control signal, the display panel is supplied with the image signal, and the light emitting panel is a display device supplied with the selection signal and the control signal.

The display device of one embodiment of the present invention includes a driving portion that supplies an image signal for controlling the display panel, a selection signal for controlling the light-emitting panel for each segment, and a control signal. Thereby, an image with a wide gradation can be displayed with high contrast. As a result, a novel display device that is highly convenient or reliable can be provided.

In the drawings attached to the present specification, the components are classified by function, and the block diagram is shown as an independent block. However, it is difficult to completely separate the actual components for each function. May involve multiple functions.

In this specification, the terms “source” and “drain” of a transistor interchange with each other depending on the polarity of the transistor or the level of potential applied to each terminal. In general, in an n-channel transistor, a terminal to which a low potential is applied is called a source, and a terminal to which a high potential is applied is called a drain. In a p-channel transistor, a terminal to which a low potential is applied is called a drain, and a terminal to which a high potential is applied is called a source. In this specification, for the sake of convenience, the connection relationship between transistors may be described on the assumption that the source and the drain are fixed. However, the names of the source and the drain are actually switched according to the above-described potential relationship. .

In this specification, the source of a transistor means a source region that is part of a semiconductor film functioning as an active layer or a source electrode connected to the semiconductor film. Similarly, a drain of a transistor means a drain region that is part of the semiconductor film or a drain electrode connected to the semiconductor film. The gate means a gate electrode.

In this specification, the state where the transistors are connected in series means, for example, a state where only one of the source and the drain of the first transistor is connected to only one of the source and the drain of the second transistor. To do. In addition, the state where the transistors are connected in parallel means that one of the source and the drain of the first transistor is connected to one of the source and the drain of the second transistor, and the other of the source and the drain of the first transistor is connected. It means a state of being connected to the other of the source and the drain of the second transistor.

In this specification, the connection means an electrical connection, and corresponds to a state where current, voltage, or potential can be supplied or transmitted. Therefore, the connected state does not necessarily indicate a directly connected state, and a wiring, a resistor, a diode, a transistor, or the like is provided so that current, voltage, or potential can be supplied or transmitted. The state of being indirectly connected through a circuit element is also included in the category.

In this specification, even when independent components on the circuit diagram are connected to each other, in practice, for example, when a part of the wiring functions as an electrode, In some cases, it also has the functions of the components. In this specification, the term “connection” includes a case where one conductive film has functions of a plurality of components.

In this specification, one of a first electrode and a second electrode of a transistor refers to a source electrode, and the other refers to a drain electrode.

According to one embodiment of the present invention, a novel light-emitting panel that is highly convenient or reliable can be provided. Alternatively, a novel display module that is highly convenient or reliable can be provided. Alternatively, a novel display device that is highly convenient or reliable can be provided. Alternatively, a novel light-emitting panel, a novel display module, a novel display device, or a novel semiconductor device can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

4A and 4B illustrate a structure of a light-emitting panel according to an embodiment. FIG. 6 is a circuit diagram illustrating a structure of a segment according to an embodiment. 8A and 8B illustrate a structure of a display module according to an embodiment. 8A and 8B illustrate a structure of a display device according to an embodiment. 10A and 10B each illustrate a structure of a segment and a transistor according to Embodiment. 3A and 3B illustrate a structure of a transistor according to an embodiment. 3A and 3B illustrate a semiconductor layer of a transistor according to an embodiment. 3A and 3B illustrate a structure of a transistor according to an embodiment. 4A to 4D illustrate a method for manufacturing a transistor according to an embodiment. 4A to 4D illustrate a method for manufacturing a transistor according to an embodiment. 4A to 4D illustrate a method for manufacturing a transistor according to an embodiment. 4A to 4D illustrate a method for manufacturing a transistor according to an embodiment. 4A and 4B illustrate a structure of a light-emitting panel according to an embodiment. 8A and 8B illustrate a structure of a display module according to an embodiment. 8A and 8B illustrate a structure of a display module according to an embodiment. 3A and 3B illustrate a structure of a transistor according to an embodiment.

A light-emitting panel of one embodiment of the present invention includes a segment circuit that is supplied with a control signal and a signal and has a function of supplying predetermined power, and a light-emitting element that is supplied with predetermined power.

Thereby, the electric power determined based on the control signal and the signal can be supplied to the light emitting element. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated.

(Embodiment 1)
In this embodiment, the structure of the light-emitting panel of one embodiment of the present invention will be described with reference to FIGS. 1, 2, 5, and 13.

FIG. 1 illustrates a structure of a light-emitting panel of one embodiment of the present invention. 1A is a projection view of the light-emitting panel 400 of one embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating a part of FIG. 1A in an enlarged manner. FIG. ) Is a cross-sectional view taken along a cutting line Z1-Z2 in FIG.

FIG. 2 is a circuit diagram illustrating a structure of a segment of the light-emitting panel of one embodiment of the present invention.

FIG. 2A is a circuit diagram illustrating the segment 402 (i, j) of the light-emitting panel 400 of one embodiment of the present invention. FIG. 2B is a circuit diagram illustrating a segment 402B (i, j) having a configuration different from that of the segment 402 (i, j).

FIG. 5 is a cross-sectional view illustrating in detail the structure shown in FIG.

FIG. 13 is a top view illustrating the configuration shown in FIG.

<Configuration Example 1 of Light-Emitting Panel>>
The light-emitting panel 400 described in this embodiment includes a first connection portion CON1, a segment circuit SC (i, j) electrically connected to the first connection portion CON1, and a first connection portion CON1. A light emitting element 450 (i, j) that is electrically connected, a first base material 410 on which a segment circuit SC (i, j) is disposed, and a light emitting element 450 (i, j) are disposed. A second base material 470 (see FIGS. 1A, 1C, and 2A).

The segment circuit SC (i, j) is electrically connected to the first power supply line VSS. The segment circuit SC (i, j) is electrically connected to the selection line GL (i), and the segment circuit is electrically connected to the signal line SL (j) (see FIG. 1B). .

The selection line GL (i) has a function of supplying a selection signal, and the signal line SL (j) has a function of supplying a control signal.

The segment circuit SC (i, j) has a function of supplying power to the first connection part CON1, and the segment circuit SC (i, j) has a function of controlling power based on the selection signal and the control signal. .

The light-emitting element 450 (i, j) includes a first electrode 451 and a second electrode 452, and the first electrode 451 is electrically connected to the first connection portion CON1, and the second electrode 452 is Are electrically connected to the second power supply line VDD.

The first electrode 451 is supplied with power, and the second power supply line VDD supplies a potential different from that of the first power supply line VSS.

The light-emitting panel 400 includes one or more segment circuits SC (i, j), and the plurality of segment circuits SC (i, j) are arranged in a matrix on the first base material 410 ( (See FIG. 1A). Note that i or j is an integer of 1 or more.

Selection line GL (i) is electrically connected to a plurality of segment circuits SC (i, j) arranged in the row direction.

The signal line SL (j) is electrically connected to a plurality of segment circuits SC (i, j) arranged in the column direction intersecting with the row direction.

The light-emitting panel 400 illustrated in this embodiment includes a segment circuit SC (i, j) that is supplied with a selection signal and a control signal and has a function of supplying power, and a light-emitting element 450 (i, j) that is supplied with power. ) And. Thereby, the electric power determined based on the control signal and the signal can be supplied to the light emitting element. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

Further, the second base material 470 includes a region overlapping with the first base material 410 (see FIG. 1C).

The second base material 470 is disposed between the light emitting element 450 (i, j) and the first base material 410.

The second base material 470 includes an opening 428a (see FIG. 1C). The first connection part CON1 includes a first wiring L1 disposed in the opening 428a (see FIG. 2A).

The light emitting panel 400 includes a second connection part CON2 that is electrically connected to the first power supply line VSS. The second base material 470 includes an opening 428b. The second connection part CON2 includes a second wiring L2 disposed in the opening 428b (see FIG. 2A). The through-hole connection method can be used for the first connection part CON1 or the second connection part CON2.

The segment circuit SC (i, j) is electrically connected to the second connection part CON2, and the first power supply line VSS and the second power supply line VDD are disposed on the second base 470.

In the segment 402 (i, j) illustrated in FIG. 2A, the first connection portion CON1 and the second connection portion CON2 include the segment circuit SC (i, j) and the light emitting element 450 (i, j). Connect electrically.

Note that in the segment 402B (i, j) illustrated in FIG. 2B, the first power supply line VSS is provided on the first base material 410, and the second connection portion CON2 is omitted.

The light-emitting panel 400 exemplified in this embodiment includes a first base material 410 on which a segment circuit SC (i, j) is disposed, and a second substrate on which a light-emitting element 450 (i, j) is disposed. The base material is overlaid, and includes a connection part CON1 that electrically connects the segment circuit SC (i, j) and the light emitting element 450 (i, j). Thereby, an external shape can be made small. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

In addition, the light-emitting panel 400 can include an optical element 450P. The optical element 450P transmits at least part of the light emitted from the light emitting element 450.

In addition, the light-emitting panel 400 can include a drive circuit GD having a function of supplying a selection signal to the selection line GL (i). Alternatively, the driver circuit SD can have a function of supplying a control signal to the signal line SL (j).

In addition, the light-emitting panel 400 can include a terminal portion 419 in which a terminal electrically connected to the control line GL (i) or a terminal electrically connected to the signal line SL (j) is disposed.

In addition, the light-emitting panel 400 can include a terminal portion 479 in which a terminal electrically connected to the first power supply line VSS or a terminal electrically connected to the second power supply line VDD is disposed.

For example, the flexible printed circuit board FPC1 can be electrically connected to the terminal portion 419 to supply various signals or power supply potentials. Further, the flexible printed circuit board FPC2 can be electrically connected to the terminal portion 479 to supply various signals or power supply potentials.

Below, each element which comprises the light emission panel 400 is demonstrated.

<Configuration example>
The light emitting panel 400 includes a first connection part CON1, a segment circuit SC (i, j), a light emitting element 450 (i, j), a first base material 410, or a second base material 470.

In addition, the light-emitting panel 400 includes a first power supply line VSS, a second power supply line VDD, a selection line GL (i), or a signal line SL (j). In addition, the first wiring L1 or the second wiring L2 is provided.

In addition, the light emitting panel 400 includes a second connection part CON2.

<< First base material >>
For example, a material having heat resistance enough to withstand a manufacturing process and a thickness and size applicable to a manufacturing apparatus can be used for the first base material 410.

An organic material, an inorganic material, a composite material of an organic material and an inorganic material, or the like can be used for the first substrate 410. For example, an inorganic material such as glass, ceramics, or metal can be used for the first base material 410.

Specifically, alkali-free glass, soda-lime glass, potash glass, crystal glass, or the like can be used for the first base material 410. Specifically, an inorganic oxide film, an inorganic nitride film, an inorganic oxynitride film, or the like can be used for the first substrate 410. For example, silicon oxide, silicon nitride, silicon oxynitride, an alumina film, or the like can be used for the first base material 410. SUS, aluminum, or the like can be used for the first base material 410.

For example, an organic material such as a resin, a resin film, or plastic can be used for the first substrate 410. Specifically, a resin film or a resin plate such as polyester, polyolefin, polyamide, polyimide, polycarbonate, or an acrylic resin can be used for the first substrate 410.

For example, a composite material in which a film such as a metal plate, a thin glass plate, or an inorganic material is attached to a resin film or the like can be used for the first base material 410. For example, a composite material in which a fibrous or particulate metal, glass, inorganic material, or the like is dispersed in a resin film can be used for the first substrate 410. For example, a composite material in which a fibrous or particulate resin, an organic material, or the like is dispersed in an inorganic material can be used for the first substrate 410.

In addition, a single layer material or a material in which a plurality of layers are stacked can be used for the first base material 410. For example, a material in which a base material and an insulating film that prevents diffusion of impurities contained in the base material are stacked can be used for the first base material 410. Specifically, a material in which one or a plurality of films selected from glass and a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or the like that prevents diffusion of impurities contained in the glass is stacked is used as the first base material 410 can be applied. Alternatively, a material in which a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like that prevents resin and diffusion of impurities that permeate the resin is stacked can be applied to the first base material 410.

<< Second base material >>
A material that can be used for the first base material 410 can be used for the second base material 470.

For example, a material that can electrically connect a wiring or a terminal formed on one surface of the second base 470 and a wiring or a terminal formed on the other surface using a through-hole connection method. Can be used.

"wiring"
A material having conductivity is used for wiring such as the first power supply line VSS, the second power supply line VDD, the selection line GL (i), the signal line SL (j), the first wiring L1, or the second wiring L2. be able to.

A material that can be used for the wiring can be used for the terminal provided in the terminal portion 419 or the terminal portion 479.

For example, an inorganic conductive material, an organic conductive material, a metal, a conductive ceramic, or the like can be used for the wiring or the terminal.

Specifically, a metal element selected from aluminum, gold, platinum, silver, copper, chromium, tantalum, titanium, molybdenum, tungsten, nickel, iron, cobalt, palladium, or manganese is used for the wiring or the terminal. it can. Alternatively, an alloy containing the above metal element can be used for the wiring or the terminal. Alternatively, an alloy or the like in which the above metal elements are combined can be used for the wiring or the terminal. In particular, an alloy of copper and manganese is suitable for fine processing using a wet etching method.

Specifically, a two-layer structure in which a titanium film is laminated on an aluminum film, a two-layer structure in which a titanium film is laminated on a titanium nitride film, a two-layer structure in which a tungsten film is laminated on a titanium nitride film, a tantalum nitride film or A two-layer structure in which a tungsten film is stacked over a tungsten nitride film, a titanium film, and a three-layer structure in which an aluminum film is stacked over the titanium film and a titanium film is further formed thereon can be used.

Specifically, a conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide added with gallium can be used for the wiring or the terminal.

Specifically, a film containing graphene or graphite can be used for the wiring or the terminal.

For example, by forming a film containing graphene oxide and reducing the film containing graphene oxide, the film containing graphene can be formed. Examples of the reduction method include a method of applying heat and a method of using a reducing agent.

Specifically, a conductive polymer can be used for the wiring or the terminal.

<< 1st connection part, 2nd connection part >>
A conductive material can be used for the first connection part CON1 or the second connection part CON2 (see FIG. 5).

For example, solder, a conductive paste, an anisotropic conductive film, or the like can be used for the first connection part CON1 or the second connection part CON2.

Specifically, an anisotropic conductive film including conductive particles CP and a material in which the particles CP are dispersed can be used.

For example, particles having a shape such as a spherical shape, a columnar shape, or a filler shape with a size of 1 μm to 200 μm, preferably 3 μm to 150 μm can be used for the particle CP.

For example, particles covered with a conductive material including nickel or gold can be used.

Specifically, particles containing polystyrene, acrylic resin, titanium oxide, or the like can be used.

For example, synthetic rubber, thermosetting resin, thermoplastic resin, or the like can be used as the material for dispersing the particles CP.

<Light emitting element>
For example, an element that includes the first electrode 451 and the second electrode 452 and converts current flowing between the first electrode 451 and the second electrode 452 into light can be used for the light-emitting element 450.

Specifically, a light-emitting diode that emits white light or the like can be used for the light-emitting element 450 (i, j).

"segment"
The segment 402 (i, j) includes a light emitting element 450 (i, j) and a segment circuit SC (i, j) electrically connected to the light emitting element 450 (i, j). A plurality of segments may be arranged in a linear style or in a pen tile style.

<Optical element>
The optical element 450P can be used for the light-emitting panel 400. The optical element 450P modulates or diffuses at least a part of the light emitted from the light emitting element 450.

Specifically, a linearly polarizing plate, a circularly polarizing plate, a diffusion plate, a prism sheet, or the like can be used for the optical element 450P.

<Segment circuit>
For example, the segment circuit SC (i, j) includes a first transistor SW, a second transistor M0, and a capacitor C (see FIG. 2A).

The first transistor SW has a gate electrically connected to the selection line GL (i) and a first electrode electrically connected to the signal line SL (j).

The second transistor M0 has a gate electrically connected to the second electrode of the first transistor SW, a first electrode electrically connected to the first connection part CON1, and a second electrode connected to the second electrode. 1 power line VSS.

In the capacitor C, the first electrode is electrically connected to the gate of the second transistor M0, and the second electrode is electrically connected to the second electrode of the second transistor M0.

<Transistor>
For example, a semiconductor film that can be formed in the same step can be used for the first transistor SW and the second transistor M0. Specifically, an oxide semiconductor film that can be formed in the same step can be used.

For example, a transistor using a Group 4 element, a compound semiconductor, an oxide semiconductor, or the like for the semiconductor layer can be used. Specifically, a transistor in which a semiconductor layer is formed using a semiconductor containing silicon, a semiconductor containing gallium arsenide, an oxide semiconductor containing indium, or the like can be used.

For example, a transistor in which single crystal silicon, polysilicon, amorphous silicon, or the like is used for a semiconductor layer can be used.

For example, a bottom-gate transistor can be used.

Note that an example of a transistor that can be used as the transistor SW or the transistor M0 is described in detail in Embodiment 4.

《Flexible printed circuit board》
The flexible printed circuit board FPC1 has a coating layer including a wiring electrically connected to the terminal portion 419, a base material supporting the wiring, and a region overlapping with the wiring. The wiring includes a region sandwiched between the base material and the coating layer and a region that does not overlap the coating layer. The flexible printed circuit board FPC2 can have the same configuration as that of the flexible printed circuit board FPC1, except that the flexible printed circuit board FPC2 includes a wiring electrically connected to the terminal portion 479.

In addition, the wiring in the area | region which does not overlap with a coating layer can be used for the terminal of flexible printed circuit board FPC1.

A conductive material can be used for wiring of the flexible printed circuit board FPC1. For example, a material that can be used for the first power supply line VSS or the like can be used for wiring of the flexible printed circuit board FPC1. Specifically, copper or the like can be used.

A material having an insulating region in a region in contact with the wiring of the flexible printed circuit board FPC1 can be used for the base material of the flexible printed circuit board FPC1.

For example, an organic material such as a resin, a resin film, or plastic can be used for the base material. Specifically, a resin layer such as polyester, polyolefin, polyamide, polyimide, polycarbonate, or acrylic resin, a resin film, or a resin plate can be used as the base material. A resin film having a glass point transition temperature of 150 ° C. or higher, preferably 200 ° C. or higher, more preferably 250 ° C. or higher and 375 ° C. or lower can be used as the substrate.

The light-emitting panel 400 illustrated in this embodiment holds a switch that can be turned on or off based on a selection signal and a charge based on a control signal supplied in the conductive state in the non-conductive state. The capacitor C is configured to include a transistor M0 that supplies electric power based on the voltage held by the capacitor C. Accordingly, the light emitting element can be driven with power based on the control signal supplied during the period in which the selection signal is supplied. As a result, a novel light-emitting panel that is highly convenient or reliable can be provided.

Note that this embodiment can be combined with any of the other embodiments described in this specification as appropriate.

(Embodiment 2)
In this embodiment, the structure of the display module of one embodiment of the present invention will be described with reference to FIGS.

FIG. 3A is a projection view illustrating the structure of the display module 600M of one embodiment of the present invention. FIG. 3B is a top view illustrating the display panel 600 illustrated in FIG. FIG. 3C is a schematic diagram illustrating the arrangement of the pixels 602 in the display panel illustrated in FIG.

FIG. 14A is a projection view illustrating the structure of the display module 600MT of one embodiment of the present invention, and FIG. 14B is a top view.

FIG. 15A is a cross-sectional view taken along section line ABCD shown in FIG. FIG. 15B is a top view illustrating an enlarged part of the display module 600MT of one embodiment of the present invention. FIG. 15C is a cross-sectional view taken along section line X5-X6 shown in FIG.

<Configuration Example of Display Module 1. >
A display module 600M described in this embodiment includes the light-emitting panel 400 described in Embodiment 1 and the display panel 600 including a region overlapping with the light-emitting panel 400 (FIGS. 3A and 3B). )reference).

The display panel 600 includes a plurality of pixels 602 in a region overlapping with one light-emitting element 450 (i, j) (see FIG. 3C). Note that the pixel 602 includes a display element.

The display module 600M illustrated in this embodiment includes a plurality of pixels in a region overlapping with the light-emitting element 450 (i, j) electrically connected to one segment circuit SC (i, j). The As a result, an image can be displayed using light whose luminance is adjusted for each segment in the backlight of the display panel 600. As a result, a novel display module that is highly convenient or reliable can be provided.

The display module 600M includes a pixel 602 including a plurality of subpixels. Specifically, the pixel 602 includes a sub-pixel 602R, a sub-pixel 602G, a sub-pixel 602B, and a sub-pixel 602Y.

The display module 600M includes a flexible printed circuit board FPC1 electrically connected to the segment circuit SC (i, j), a flexible printed circuit board FPC2 electrically connected to the light emitting element 450 (i, j), and the display panel 600. And a flexible printed circuit board FPC3 that is electrically connected to the circuit board.

The flexible printed circuit board FPC3 can supply an image signal or the like to the display panel 600, for example.

Hereinafter, individual elements constituting the display module 600M will be described.

<Configuration example>
The display module 600M includes a light emitting panel 400 and a display panel 600.

The display module 600M includes a flexible printed circuit board FPC1, a flexible printed circuit board FPC2, or a flexible printed circuit board FPC3.

<Display panel>
The pixel 602 can be used for the display panel 600.

A plurality of subpixels can be used for the pixel 602. For example, a subpixel 602R, a subpixel 602G, a subpixel 602B, and a subpixel 602Y can be used. Specifically, a subpixel 602R that displays red, a subpixel 602G that displays green, a subpixel 602B that displays blue, a subpixel 602Y that displays yellow, and the like can be used.

For example, a display element having a function of controlling light transmission can be used for the pixel 602 or the sub-pixel of the display panel 600. For example, a liquid crystal display element or a shutter-type MEMS display element can be used.

Specifically, an IPS (In-Plane-Switching) mode, a TN (Twisted Nematic) mode, an FFS (Fringe Field Switching) mode, an ASM (Axial Symmetrical Aligned Micro-cell) mode, and an OCB (Op ted Cic mode). A liquid crystal element such as a (Ferroelectric Liquid Crystal) mode or an AFLC (Antiferroelectric Liquid Crystal) mode can be used.

Specifically, DMS (Digital Micro Shutter) or MIRASOL (registered trademark) element can be used.

《Flexible printed circuit board》
A material that can be used for the flexible printed circuit board FPC1 described in Embodiment 1 can be used for the flexible printed circuit board FPC3.

<Configuration Example of Display Module 2. >
A display module 600MT described in this embodiment has a structure similar to that of the display module 600M except that the display module 600MT includes a proximity sensor (see FIG. 14A). Note that the display module 600MT including the proximity sensor can be referred to as a touch panel module.

The display panel 600T includes a proximity sensor. Note that the display panel 600T including the proximity sensor can be referred to as a touch panel.

The display panel 600T includes a flexible printed circuit board FPC4 that is electrically connected to the proximity sensor. The display panel 600T includes a sub-pixel 602R and a drive circuit SD6. In addition, a wiring 611 that is electrically connected to the sub-pixel 602R or the driver circuit is provided (see FIGS. 14B and 15A).

The wiring 611 is electrically connected to the terminal 619, and the terminal 619 is electrically connected to the flexible printed circuit board FPC4 through the connection member ACF.

The drive circuit SD6 is electrically connected to the subpixel 602R and includes a transistor MD or a capacitive element CD.

《Subpixel》
The sub-pixel 602R includes a liquid crystal element 650R and a pixel circuit electrically connected to the liquid crystal element 650R, and the pixel circuit includes a transistor M6.

Note that when a transistor with extremely small leakage current is used for the pixel circuit, the pixel circuit can hold charge for a long time. For example, a transistor including an oxide semiconductor in a semiconductor film can be used for the pixel circuit. Specifically, when the transistor described in Embodiment 4 is used for a pixel circuit, the refresh rate of the pixel can be set to 60 Hz or lower, 30 Hz or lower, preferably 1 Hz or lower. Accordingly, a still image can be displayed without rewriting the pixel circuit, for example, for 1 second or longer, preferably 1 minute or longer. As a result, a display in which flicker is suppressed can be displayed.

The liquid crystal element 650R includes a layer 653 containing liquid crystal, and a first electrode 651 and a second electrode 652 arranged so that an electric field can be applied to the layer 653 containing liquid crystal.

The layer 653 including liquid crystal is provided in a region surrounded by the base material 610, the base material 670, and the sealing material 605.

The insulating film 621 is provided between the first electrode 651 and the second electrode 652.

《Proximity sensor》
The proximity sensor 675 includes a control line CL (i) and a signal line ML (j) that intersects the control line CL (i). In addition, an electrode C1 (i) electrically connected to the control line CL (i) and an electrode C2 (j) electrically connected to the signal line ML (j) are provided (see FIG. 15B). .

The control line CL (i) includes a wiring BR (i, j) at a portion intersecting with the signal line ML (j) (see FIGS. 15B and 15C). Note that the insulating film 671 is provided between the wiring BR (i, j) and the signal line ML (j).

<Others>
The light shielding layer BM includes an opening in a region overlapping with the liquid crystal element 650R (see FIG. 15A).

The colored layer CF includes a region overlapping with the opening of the light shielding layer BM.

An optical element 450P and an optical element 670P are provided. The liquid crystal element 650R is disposed between the optical elements 450P and 670P.

Note that this embodiment can be combined with any of the other embodiments described in this specification as appropriate.

(Embodiment 3)
In this embodiment, the structure of the display device of one embodiment of the present invention is described with reference to FIGS.

FIG. 4 illustrates a structure of a display device of one embodiment of the present invention. FIG. 4A is a block diagram of a display device 3000 according to one embodiment of the present invention.

FIG. 4B is a projection view illustrating the appearance of the display device 3000 described with reference to FIG.

FIG. 4C illustrates an appearance of a display device 3000B having an appearance different from that of the display device 3000 described with reference to FIG.

<Configuration example of display device>
A display device 3000 described in this embodiment includes a display module 600M described in Embodiment 2 and a driver 3500 electrically connected to the display module 600M (see FIG. 4A).

The driving unit 3500 has a function of supplying the image signal 10, the selection signal 11, and the control signal 12.

The display panel 600 is supplied with the image signal 10, and the light emitting panel 400 is supplied with the selection signal 11 and the control signal 12.

A display device 3000 described in this embodiment includes an image signal 10 for controlling the display panel 600, a selection signal 11 for controlling the light-emitting panel 400 for each segment, and a drive unit 3500 for supplying a control signal 12. . Thereby, an image with a wide gradation can be displayed with high contrast. As a result, a novel display device that is highly convenient or reliable can be provided.

The driving unit 3500 includes a display panel driving unit 3560 and a light emitting panel driving unit 3540. The display panel driving unit 3560 supplies the image signal 10, and the light emitting panel driving unit 3540 supplies the selection signal 11 and the control signal 12.

In addition, the display device 3000 includes a calculation unit 3100. The calculation unit 3100 includes a function for generating image information and a storage unit 3110 for storing the generated image information. The storage unit 3110 can be used for a frame memory, for example.

The calculation unit 3100 supplies the signal 13 and the signal 14 to the drive unit 3500 based on the image information stored in the storage unit 3110.

For example, the display device 3000 can display an image using a local dimming method.

Specifically, in the first step, the arithmetic unit 3100 determines a representative value from gradation information included in a predetermined image displayed in a region overlapping with a plurality of light emitting elements. Specifically, the average value is determined from the gradation information of a predetermined image displayed in the area overlapping with the light emitting element 450 (i, j).

In the second step, the luminance for causing the light emitting element to emit light is determined based on the representative value. Specifically, the luminance for causing the light emitting element 450 (i, j) to emit light is determined.

In a third step, a signal 14 is provided to illuminate the light emitting element with the determined brightness. Specifically, a signal 14 is supplied that causes the light-emitting element 450 (i, j) that overlaps the bright area to emit light with higher luminance than the light-emitting element that overlaps the dark area.

In the fourth step, the signal 13 is supplied so that a predetermined image is displayed in a region overlapping with the light emitting element 450 (i, j) that emits light with the luminance determined in the third step.

The light emitting panel 400 includes light emitting elements 450 (i, j) arranged in a matrix. The light emitting element 450 (i, j) is electrically connected to the segment circuit SC (i, j), and the luminance of each light emitting element can be controlled independently using the segment circuit.

In addition, the light emitting element 450 (i, j) may emit light based on the control signal supplied together with the one selection signal during a period from the supply of the one selection signal to the supply of the next selection signal. it can. Accordingly, the number of light-emitting elements provided in the light-emitting panel 400 can be increased without shortening the period during which one light-emitting element 450 (i, j) emits light. As a result, it is possible to divide the backlight into fine regions, and solve the problem that a portion in which contrast is difficult to improve when roughly divided is generated at the boundary of the regions.

Specifically, in the display panel 600 in which 3800 or more, preferably 7500 or more and 17000 or less pixels are arranged in the horizontal direction, and 2100 or more, preferably 4500 or more and 10,000 or less pixels are arranged in the vertical direction. 380 to 780 light emitting elements are arranged in the horizontal direction, and 210 to 450 light emitting elements are arranged in the vertical direction.

Alternatively, in the display panel 600 having a diagonal dimension of 10 inches (25.4 cm) or more, preferably 21 inches (53.3 cm) or more and 32 inches or less, 92 to 192 light emitting elements are arranged in the horizontal direction, 54 to 108 light-emitting elements are arranged in the vertical direction. Further, it can be used for a large display device of 32 inches or more, 60 inches or more, 80 inches or more, or 152 inches or more, for example, a television system.

<< Configuration Example 1 >>
The display device 3000 includes a display module 600M, a display panel 600, a light emitting panel 400, a driving unit 3500, a display panel driving unit 3560, a light emitting panel driving unit 3540, a calculation unit 3100, or a storage unit 3110. In addition, the housing 3001 or the operation unit RC is provided.

The housing 3001 houses the display module 600M, the drive unit 3500, and the calculation unit 3100. The operation unit RC supplies a display command and the like to the display device.

<< Configuration Example 2 >>
The display device 3000B has the same configuration as the display device 3000 except that the display module 600MB and the housing 3001B are smaller.

Note that this embodiment can be combined with any of the other embodiments described in this specification as appropriate.

(Embodiment 4)
In this embodiment, a structure and a manufacturing method of a transistor that can be used for the light-emitting panel of one embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a cross-sectional view illustrating the structure of the light-emitting panel of one embodiment of the present invention to which the transistor described in this embodiment is applied. Specifically, the transistor 100 described in this embodiment is applied to the light-emitting panel 400 described in Embodiment 1.

6 to 8 are a top view and a cross-sectional view illustrating a structure of a transistor that can be used for the light-emitting panel 400 of one embodiment of the present invention.

9 to 12 are cross-sectional views illustrating a method for manufacturing a transistor that can be used for the light-emitting panel 400 of one embodiment of the present invention.

<Configuration Example 1 of Semiconductor Device>
6A is a top view of the transistor 100 that can be used for the light-emitting panel of one embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along the dashed-dotted line X1-X2 in FIG. 6A. 6C corresponds to a cross-sectional view of a cross section taken along a dashed-dotted line Y1-Y2 in FIG. 6A. Note that in FIG. 6A, some components (such as an insulating film functioning as a gate insulating film) are not illustrated in order to avoid complexity. The direction of the alternate long and short dash line X1-X2 may be referred to as a channel length direction, and the direction of the alternate long and short dash line Y1-Y2 may be referred to as a channel width direction. Note that in the top view of the transistor, some components may be omitted in the following drawings as in FIG. 6A.

The transistor 100 includes a conductive film 104 functioning as a gate electrode over a base material 410, an insulating film 106 over the base material 410 and the conductive film 104, an insulating film 107 over the insulating film 106, and an oxide over the insulating film 107. A semiconductor film, a conductive film 112a functioning as a source electrode electrically connected to the oxide semiconductor film 108, and a conductive film 112b functioning as a drain electrode electrically connected to the oxide semiconductor film 108 Have. In addition, insulating films 114 and 116 and an insulating film 118 are provided over the transistor 100, more specifically, over the conductive films 112 a and 112 b and the oxide semiconductor film 108. The insulating films 114, 116, and 118 function as protective insulating films for the transistor 100. Note that an insulating film 421 including a region overlapping with the insulating film 118 may be provided over the insulating film 118 (see FIG. 5).

The oxide semiconductor film 108 includes a first oxide semiconductor film 108a on the conductive film 104 side that functions as a gate electrode and a second oxide semiconductor film 108b over the first oxide semiconductor film 108a. Have. The insulating film 106 and the insulating film 107 have a function as a gate insulating film of the transistor 100.

As the oxide semiconductor film 108, an In-M (M represents Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf) oxide or an In-M-Zn oxide is used. it can. In particular, an In-M-Zn oxide is preferably used for the oxide semiconductor film 108.

The first oxide semiconductor film 108a includes a first region in which the atomic ratio of In is larger than the atomic ratio of M. In addition, the second oxide semiconductor film 108b includes a second region in which the atomic ratio of In is smaller than that of the first oxide semiconductor film 108a. The second region has a thinner part than the first region.

When the first oxide semiconductor film 108a includes the first region in which the atomic ratio of In is larger than the atomic ratio of M, the field-effect mobility of the transistor 100 (sometimes simply referred to as mobility or μFE). Can be high. Specifically, the field effect mobility of the transistor 100 can exceed 10 cm ² / Vs.

For example, the above-described transistor having a high field-effect mobility is used for a gate driver that generates a gate signal (particularly, a demultiplexer connected to an output terminal of a shift register included in the gate driver). A semiconductor device or a display device (also referred to as a frame) can be provided.

On the other hand, with the use of the first oxide semiconductor film 108a including the first region in which the atomic ratio of In is larger than the atomic ratio of M, the electrical characteristics of the transistor 100 easily change during light irradiation. However, in the semiconductor device of one embodiment of the present invention, the second oxide semiconductor film 108b is formed over the first oxide semiconductor film 108a. In addition, the thickness of the channel region of the second oxide semiconductor film 108b is smaller than the thickness of the first oxide semiconductor film 108a.

Further, since the second oxide semiconductor film 108b includes the second region in which the atomic ratio of In is smaller than that of the first oxide semiconductor film 108a, Eg is larger than that of the first oxide semiconductor film 108a. Become. Therefore, the oxide semiconductor film 108 having a stacked structure of the first oxide semiconductor film 108a and the second oxide semiconductor film 108b has high resistance due to the optical negative bias stress test.

With the oxide semiconductor film having the above structure, the amount of light absorbed by the oxide semiconductor film 108 during light irradiation can be reduced. Accordingly, variation in electrical characteristics of the transistor 100 during light irradiation can be suppressed. In the semiconductor device of one embodiment of the present invention, the insulating film 114 or the insulating film 116 contains excess oxygen; thus, variation in electrical characteristics of the transistor 100 due to light irradiation can be further suppressed. .

Here, the oxide semiconductor film 108 is described in detail with reference to FIGS.

FIG. 7 is an enlarged cross-sectional view of the vicinity of the oxide semiconductor film 108 of the transistor 100 illustrated in FIG.

In FIG. 7, the thickness of the first oxide semiconductor film 108a is denoted by t1, and the thickness of the second oxide semiconductor film 108b is denoted by t2-1 and t2-2. Since the second oxide semiconductor film 108b is provided over the first oxide semiconductor film 108a, the first oxide semiconductor film 108a is etched or etched when the conductive films 112a and 112b are formed. There is no exposure to solutions. Therefore, the first oxide semiconductor film 108a is not reduced or very little. On the other hand, in the second oxide semiconductor film 108b, when the conductive films 112a and 112b are formed, portions of the second oxide semiconductor film 108b that do not overlap with the conductive films 112a and 112b are etched to form recesses. The That is, the thickness of the region overlapping the conductive films 112a and 112b of the second oxide semiconductor film 108b is t2-1, and the thickness of the region not overlapping the conductive films 112a and 112b of the second oxide semiconductor film 108b is t2. t2-2.

The relation between the thicknesses of the first oxide semiconductor film 108a and the second oxide semiconductor film 108b is preferably t2-1> t1> t2-2. With such a film thickness relationship, a transistor having high field effect mobility and a small amount of fluctuation in threshold voltage during light irradiation can be obtained.

Further, in the oxide semiconductor film 108 included in the transistor 100, when oxygen vacancies are formed, electrons serving as carriers are generated, which tends to be normally on. Therefore, reducing oxygen vacancies in the oxide semiconductor film 108, particularly oxygen vacancies in the first oxide semiconductor film 108a is important in obtaining stable transistor characteristics. Therefore, in the structure of the transistor of one embodiment of the present invention, excess oxygen is introduced into the insulating film over the oxide semiconductor film 108, here, the insulating film 114 and / or the insulating film 116 over the oxide semiconductor film 108. Thus, oxygen is transferred from the insulating film 114 and / or the insulating film 116 into the oxide semiconductor film 108, so that oxygen vacancies in the oxide semiconductor film 108, particularly in the first oxide semiconductor film 108a, are filled. Features.

Note that the insulating films 114 and 116 preferably have a region containing oxygen in excess of the stoichiometric composition (oxygen-excess region). In other words, the insulating films 114 and 116 are insulating films capable of releasing oxygen. Note that in order to provide the oxygen-excess region in the insulating films 114 and 116, for example, oxygen is introduced into the insulating films 114 and 116 after film formation to form the oxygen-excess region. As a method for introducing oxygen, an ion implantation method, an ion doping method, a plasma immersion ion implantation method, a plasma treatment, or the like can be used.

In order to fill oxygen vacancies in the first oxide semiconductor film 108a, it is preferable to reduce the thickness of the second oxide semiconductor film 108b near the channel region. Therefore, the relationship of t2-2 <t1 may be satisfied. For example, the thickness of the second oxide semiconductor film 108b in the vicinity of the channel region is preferably 1 nm to 20 nm, and more preferably 3 nm to 10 nm.

Hereinafter, other components included in the semiconductor device of the present embodiment will be described in detail.

<Board>
Although there is no big restriction | limiting in the material of the base material 410, etc., it is necessary to have the heat resistance of the grade which can endure at least heat processing after that. For example, a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, or the like may be used as the base material 410. It is also possible to apply a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc., and a semiconductor element provided on these substrates May be used as the substrate 410. When a glass substrate is used as the base material 410, the sixth generation (1500 mm × 1850 mm), the seventh generation (1870 mm × 2200 mm), the eighth generation (2200 mm × 2400 mm), the ninth generation (2400 mm × 2800 mm), the first By using a large-area substrate of 10 generations (2950 mm × 3400 mm) or the like, a large display device can be manufactured.

Alternatively, a flexible substrate may be used as the base material 410, and the transistor 100 may be formed directly over the flexible substrate. Alternatively, a separation layer may be provided between the base material 410 and the transistor 100. The separation layer can be used to separate a part from the base material 410 and transfer it to another substrate after a semiconductor device is partially or entirely completed thereon. At that time, the transistor 100 can be transferred to a substrate having poor heat resistance or a flexible substrate.

<Conductive film that functions as a gate electrode, a source electrode, and a drain electrode>
As the conductive film 104 functioning as a gate electrode, the conductive film 112a functioning as a source electrode, and the conductive film 112b functioning as a drain electrode, chromium (Cr), copper (Cu), aluminum (Al), gold (Au) , Silver (Ag), zinc (Zn), molybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), manganese (Mn), nickel (Ni), iron (Fe), cobalt (Co) Each of these can be formed using a metal element selected from the above, an alloy containing the above-described metal element as a component, an alloy combining the above-described metal elements, or the like.

In addition, the conductive films 104, 112a, and 112b may have a single-layer structure or a stacked structure including two or more layers. For example, a single-layer structure of an aluminum film containing silicon, a two-layer structure in which a titanium film is stacked on an aluminum film, a two-layer structure in which a titanium film is stacked on a titanium nitride film, and a two-layer structure in which a tungsten film is stacked on a titanium nitride film Layer structure, two-layer structure in which a tungsten film is stacked on a tantalum nitride film or tungsten nitride film, a three-layer structure in which a titanium film, an aluminum film is stacked on the titanium film, and a titanium film is further formed thereon is there. Alternatively, aluminum may be an alloy film or a nitride film in which one or a combination selected from titanium, tantalum, tungsten, molybdenum, chromium, neodymium, and scandium is used.

The conductive films 104, 112a, and 112b include indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, and indium tin oxide containing titanium oxide. Alternatively, a light-transmitting conductive material such as indium zinc oxide or indium tin oxide to which silicon oxide is added can be used.

Further, a Cu—X alloy film (X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) may be applied to the conductive films 104, 112a, and 112b. By using a Cu-X alloy film, it can be processed by a wet etching process, and thus manufacturing costs can be suppressed.

<Insulating film that functions as a gate insulating film>
As the insulating films 106 and 107 functioning as the gate insulating film of the transistor 100, a plasma enhanced chemical vapor deposition (PECVD) method, a sputtering method, or the like is used to form a silicon oxide film, a silicon oxynitride film, or a nitride film. One or more kinds of silicon oxide film, silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film and neodymium oxide film Each insulating layer can be used. Note that instead of the stacked structure of the insulating films 106 and 107, a single-layer insulating film selected from the above materials or an insulating film having three or more layers may be used.

The insulating film 106 functions as a blocking film that suppresses permeation of oxygen. For example, in the case where excess oxygen is supplied into the insulating films 107, 114, and / or the oxide semiconductor film 108, the insulating film 106 can suppress permeation of oxygen.

Note that the insulating film 107 in contact with the oxide semiconductor film 108 functioning as the channel region of the transistor 100 is preferably an oxide insulating film, and includes a region containing oxygen in excess of the stoichiometric composition (oxygen-excess region). ) Is more preferable. In other words, the insulating film 107 is an insulating film capable of releasing oxygen. In order to provide the oxygen-excess region in the insulating film 107, for example, the insulating film 107 may be formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 107 after film formation to form an oxygen excess region. As a method for introducing oxygen, an ion implantation method, an ion doping method, a plasma immersion ion implantation method, a plasma treatment, or the like can be used.

Further, when hafnium oxide is used as the insulating film 107, the following effects are obtained. Hafnium oxide has a higher dielectric constant than silicon oxide or silicon oxynitride. Therefore, since the physical film thickness can be increased with respect to the equivalent oxide film thickness, the leakage current due to the tunnel current can be reduced even when the equivalent oxide film thickness is 10 nm or less or 5 nm or less. That is, a transistor with a small off-state current can be realized. Further, hafnium oxide having a crystal structure has a higher dielectric constant than hafnium oxide having an amorphous structure. Therefore, in order to obtain a transistor with low off-state current, it is preferable to use hafnium oxide having a crystal structure. Examples of the crystal structure include a monoclinic system and a cubic system. Note that one embodiment of the present invention is not limited thereto.

Note that in this embodiment, a silicon nitride film is formed as the insulating film 106 and a silicon oxide film is formed as the insulating film 107. A silicon nitride film has a higher relative dielectric constant than a silicon oxide film and a large film thickness necessary for obtaining a capacitance equivalent to that of a silicon oxide film. Therefore, a silicon nitride film is used as a gate insulating film of the transistor 150. Insulating film can be physically thickened. Accordingly, a decrease in the withstand voltage of the transistor 100 can be suppressed, and further, the withstand voltage can be improved, thereby suppressing electrostatic breakdown of the transistor 100.

<Oxide semiconductor film>
For the oxide semiconductor film 108, any of the above materials can be used. In the case where the oxide semiconductor film 108 is an In-M-Zn oxide, the atomic ratio of metal elements of a sputtering target used for forming the In-M-Zn oxide satisfies In ≧ M and Zn ≧ M. It is preferable. As the atomic ratio of the metal elements of such a sputtering target, In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, In: M: Zn = 2: 1: 3, In: M: Zn = 3: 1: 2, and In: M: Zn = 4: 2: 4.1 are preferable. In the case where the oxide semiconductor film 108 is an In-M-Zn oxide, a target including a polycrystalline In-M-Zn oxide is preferably used as the sputtering target. By using a target including a polycrystalline In-M-Zn oxide, the oxide semiconductor film 108 having crystallinity can be easily formed. Note that the atomic ratio of the oxide semiconductor film 108 to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target as an error. For example, when the atomic ratio of In: Ga: Zn = 4: 2: 4.1 is used as the sputtering target, the atomic ratio of the oxide semiconductor film 108 to be formed is In: Ga: Zn = 4: There may be a case in the vicinity of 2: 3.

For example, as the first oxide semiconductor film 108a, the above-described In: M: Zn = 2: 1: 3, In: M: Zn = 3: 1: 2, and In: M: Zn = 4: 2: 4 are used. .1 etc. may be used. The second oxide semiconductor film 108b may be formed using the above-described In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, or the like. Note that the atomic ratio of the metal elements of the sputtering target used for the second oxide semiconductor film 108b does not need to satisfy In ≧ M and Zn ≧ M, and may have a composition satisfying In ≧ M and Zn <M. Specifically, In: M: Zn = 1: 3: 2, etc. are mentioned.

The oxide semiconductor film 108 has an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more. In this manner, off-state current of the transistor 100 can be reduced by using an oxide semiconductor with a wide energy gap. In particular, an oxide semiconductor film with an energy gap of 2 eV or more, preferably 2 eV or more and 3.0 eV or less is used for the first oxide semiconductor film 108a, and an energy gap of 2 e is used for the second oxide semiconductor film 108b. It is preferable to use an oxide semiconductor film with a thickness of 0.5 eV to 3.5 eV. In addition, the energy gap of the second oxide semiconductor film 108b is preferably larger than that of the first oxide semiconductor film 108a.

The thickness of each of the first oxide semiconductor film 108a and the second oxide semiconductor film 108b is 3 nm to 200 nm, preferably 3 nm to 100 nm, more preferably 3 nm to 50 nm. Note that it is preferable that the film thickness relationship described above is satisfied.

As the second oxide semiconductor film 108b, an oxide semiconductor film with low carrier density is used. For example, the second oxide semiconductor film 108b has a carrier density of 1 × 10 ¹⁷ pieces / cm ³ or less, preferably 1 × 10 ¹⁵ pieces / cm ³ or less, more preferably 1 × 10 ¹³ pieces / cm ³ or less. More preferably, it is 1 × 10 ¹¹ pieces / cm ³ or less.

Note that the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, and the like) of the transistor. In order to obtain the required semiconductor characteristics of the transistor, the carrier density, impurity concentration, defect density, and atomic ratio of metal element to oxygen of the first oxide semiconductor film 108a and the second oxide semiconductor film 108b It is preferable to make the interatomic distance, density, etc. appropriate.

Note that as the first oxide semiconductor film 108a and the second oxide semiconductor film 108b, an oxide semiconductor film with a low impurity concentration and a low density of defect states is used, so that even better electrical characteristics can be obtained. A transistor having the same can be manufactured, which is preferable. Here, low impurity concentration and low defect level density (low oxygen deficiency) are referred to as high purity intrinsic or substantially high purity intrinsic. A highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has few carrier generation sources, and thus can have a low carrier density. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film rarely has electrical characteristics (also referred to as normally-on) in which the threshold voltage is negative. In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and thus may have a low density of trap states. Further, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has an extremely small off-state current, a channel width of 1 × 10 ⁶ μm, and a channel length L of 10 μm. When the voltage between the drain electrodes (drain voltage) is in the range of 1V to 10V, it is possible to obtain a characteristic that the off-current is less than the measurement limit of the semiconductor parameter analyzer, that is, 1 × 10 ⁻¹³ A or less.

Therefore, a transistor in which a channel region is formed in the high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor film can have a small variation in electrical characteristics and can be a highly reliable transistor. Note that the charge trapped in the trap level of the oxide semiconductor film takes a long time to disappear, and may behave as if it were a fixed charge. Therefore, a transistor in which a channel region is formed in an oxide semiconductor film with a high trap state density may have unstable electrical characteristics. Examples of impurities include hydrogen, nitrogen, alkali metals, and alkaline earth metals.

Hydrogen contained in the oxide semiconductor film reacts with oxygen bonded to metal atoms to become water, and forms oxygen vacancies in a lattice from which oxygen is released (or a portion from which oxygen is released). When hydrogen enters the oxygen vacancies, electrons serving as carriers may be generated. In addition, a part of hydrogen may be combined with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor including an oxide semiconductor film containing hydrogen is likely to be normally on. Therefore, it is preferable that hydrogen be reduced in the oxide semiconductor film 108 as much as possible. Specifically, in the oxide semiconductor film 108, the hydrogen concentration obtained by SIMS analysis is 2 × 10 ²⁰ atoms / cm ³ or less, preferably 5 × 10 ¹⁹ atoms / cm ³ or less, more preferably 1 × 10 ^19. atoms / cm ³ or less, 5 × 10 ¹⁸ atoms / cm ³ or less, preferably 1 × 10 ¹⁸ atoms / cm ³ or less, more preferably 5 × 10 ¹⁷ atoms / cm ³ or less, more preferably 1 × 10 ¹⁶ atoms / cm ³ or less. cm ³ or less.

The first oxide semiconductor film 108a preferably includes a portion with a lower hydrogen concentration than the second oxide semiconductor film 108b. Since the first oxide semiconductor film 108a has a portion with a lower hydrogen concentration than the second oxide semiconductor film 108b, a highly reliable semiconductor device can be obtained.

In addition, when silicon or carbon which is one of Group 14 elements is included in the first oxide semiconductor film 108a, oxygen vacancies increase in the first oxide semiconductor film 108a, and the n-type oxide semiconductor film 108a is formed. Therefore, the concentration of silicon or carbon in the first oxide semiconductor film 108a and the concentration of silicon or carbon in the vicinity of the interface with the first oxide semiconductor film 108a (concentration obtained by SIMS analysis) are 2 × 10. ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

In the first oxide semiconductor film 108a, the concentration of alkali metal or alkaline earth metal obtained by SIMS analysis is 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less. To do. When an alkali metal and an alkaline earth metal are combined with an oxide semiconductor, carriers may be generated, and the off-state current of the transistor may be increased. Therefore, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the first oxide semiconductor film 108a.

In addition, when nitrogen is contained in the first oxide semiconductor film 108a, electrons as carriers are generated, the carrier density is increased, and the n-type is easily obtained. As a result, a transistor including an oxide semiconductor film containing nitrogen is likely to be normally on. Therefore, nitrogen in the oxide semiconductor film is preferably reduced as much as possible. For example, the nitrogen concentration obtained by SIMS analysis is preferably 5 × 10 ¹⁸ atoms / cm ³ or less.

The first oxide semiconductor film 108a and the second oxide semiconductor film 108b may each have a non-single-crystal structure. The non-single-crystal structure includes, for example, a CAAC-OS (C Axis Crystallized Oxide Semiconductor) described later, a polycrystalline structure, a microcrystalline structure, or an amorphous structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.

<Insulating film that functions as a protective insulating film of a transistor>
The insulating films 114 and 116 have a function of supplying oxygen to the oxide semiconductor film 108. The insulating film 118 has a function as a protective insulating film of the transistor 100. In addition, the insulating films 114 and 116 include oxygen. The insulating film 114 is an insulating film that can transmit oxygen. Note that the insulating film 114 also functions as a damage reducing film for the oxide semiconductor film 108 when an insulating film 116 to be formed later is formed.

As the insulating film 114, silicon oxide, silicon oxynitride, or the like with a thickness of 5 nm to 150 nm, preferably 5 nm to 50 nm can be used.

The insulating film 114 preferably has a small amount of defects. Typically, the ESR measurement indicates that the spin density of a signal appearing at g = 2.001 derived from a dangling bond of silicon is 3 × 10 ¹⁷ spins / It is preferable that it is cm ³ or less. This is because when the density of defects contained in the insulating film 114 is large, oxygen is bonded to the defects, and the amount of oxygen transmitted through the insulating film 114 is reduced.

Note that in the insulating film 114, all of the oxygen that has entered the insulating film 114 from the outside does not move to the outside of the insulating film 114 but also remains in the insulating film 114. Further, oxygen enters the insulating film 114 and oxygen contained in the insulating film 114 may move to the outside of the insulating film 114, so that oxygen may move in the insulating film 114. When an oxide insulating film that can transmit oxygen is formed as the insulating film 114, oxygen released from the insulating film 116 provided over the insulating film 114 is transferred to the oxide semiconductor film 108 through the insulating film 114. Can be made.

The insulating film 114 includes an oxide insulating film in which the level density of nitrogen oxide is low between the energy (E _{v — os} ) at the upper end of the valence band of the oxide semiconductor film and the energy (E _{c — os} ) at the lower end of the conduction band. Can be used. As an oxide insulating film having a low nitrogen oxide level density between E _{v — os} and E _{c — os,} a silicon oxynitride film with a low nitrogen oxide emission amount, an aluminum oxynitride film with a low nitrogen oxide emission amount, or the like Can be used.

Note that a silicon oxynitride film with a small amount of released nitrogen oxide is a film in which the amount of released ammonia is larger than the amount of released nitrogen oxide in the temperature programmed desorption gas analysis method. Typically, the amount of released ammonia is Is 1 × 10 ¹⁸ pieces / cm ³ or more and 5 × 10 ¹⁹ pieces / cm ³ or less. Note that the amount of ammonia released is the amount released by heat treatment at a film surface temperature of 50 ° C. to 650 ° C., preferably 50 ° C. to 550 ° C.

Nitrogen oxide (NO _x , x is 0 or more and 2 or less, preferably 1 or more and 2 or less), typically NO ₂ or NO forms a level in the insulating film 114 or the like. The level is located in the energy gap of the oxide semiconductor film 108. Therefore, when nitrogen oxide diffuses to the interface between the insulating film 114 and the oxide semiconductor film 108, the level may trap electrons on the insulating film 114 side. As a result, trapped electrons remain in the vicinity of the interface between the insulating film 114 and the oxide semiconductor film 108, so that the threshold voltage of the transistor is shifted in the positive direction.

Nitrogen oxide reacts with ammonia and oxygen in heat treatment. Since nitrogen oxide contained in the insulating film 114 reacts with ammonia contained in the insulating film 116 in the heat treatment, nitrogen oxide contained in the insulating film 114 is reduced. Therefore, electrons are hardly trapped at the interface between the insulating film 114 and the oxide semiconductor film 108.

By using an oxide insulating film having a low nitrogen oxide level density between E _{v — os} and E _{c — os} as the insulating film 114, a shift in threshold voltage of the transistor can be reduced. Variations in electrical characteristics can be reduced.

Note that the insulating film 114 has a g value of 2.037 or more in a spectrum obtained by measurement with an ESR of 100 K or less by heat treatment in a manufacturing process of the transistor, typically 300 ° C. or more and less than 350 ° C. A first signal having a g value of 2.001 or more and 2.003 or less and a third signal having a g value of 1.964 or more and 1.966 or less are observed. The split width of the first signal and the second signal and the split width of the second signal and the third signal are about 5 mT in the X-band ESR measurement. In addition, the first signal having a g value of 2.037 to 2.039, the second signal having a g value of 2.001 to 2.003, and the g value of 1.964 to 1.966. The total density of the spins of the third signal is less than 1 × 10 ¹⁸ spins / cm ³ , typically 1 × 10 ¹⁷ spins / cm ³ or more and less than 1 × 10 ¹⁸ spins / cm ³ .

In the ESR spectrum of 100K or less, a first signal having a g value of 2.037 to 2.039, a second signal having a g value of 2.001 to 2.003, and a g value of 1.964 to 1 A third signal of .966 or less corresponds to a signal caused by nitrogen oxides (NO _x , x is 0 or more and 2 or less, preferably 1 or more and 2 or less). Typical examples of nitrogen oxides include nitrogen monoxide and nitrogen dioxide. That is, the first signal having a g value of 2.037 to 2.039, the second signal having a g value of 2.001 to 2.003, and the g value of 1.964 to 1.966. It can be said that the smaller the total density of spins of the third signal, the smaller the content of nitrogen oxide contained in the oxide insulating film.

In addition, the oxide insulating film in which the level density of nitrogen oxide is low between E _{v — os} and E _{c — os} has a nitrogen concentration measured by SIMS of 6 × 10 ²⁰ atoms / cm ³ or less.

An oxide insulating film with a low nitrogen oxide level density is formed between _{Ev_os} and _{Ec_os} by using a PECVD method with a substrate temperature of 220 ° C. or higher and 350 ° C. or lower and using silane and dinitrogen monoxide. By doing so, a dense and high hardness film can be formed.

The insulating film 116 is formed using an oxide insulating film containing more oxygen than that in the stoichiometric composition. Part of oxygen is released by heating from the oxide insulating film containing oxygen in excess of that in the stoichiometric composition. An oxide insulating film containing oxygen in excess of the stoichiometric composition has an oxygen desorption amount of 1.0 × 10 ¹⁹ atoms / cm ³ or more in terms of oxygen atoms in TDS analysis. The oxide insulating film is preferably 3.0 × 10 ²⁰ atoms / cm ³ or more. The surface temperature of the film at the time of the TDS analysis is preferably in the range of 100 ° C. to 700 ° C., or 100 ° C. to 500 ° C.

As the insulating film 116, silicon oxide, silicon oxynitride, or the like with a thickness of 30 nm to 500 nm, preferably 50 nm to 400 nm can be used.

The insulating film 116 preferably has a small amount of defects. Typically, the ESR measurement shows that the spin density of a signal appearing at g = 2.001 derived from a dangling bond of silicon is 1.5 × 10 ^18. It is preferably less than spins / cm ³ and more preferably 1 × 10 ¹⁸ spins / cm ³ or less. Note that the insulating film 116 is farther from the oxide semiconductor film 108 than the insulating film 114, and thus has a higher defect density than the insulating film 114.

In addition, since the insulating films 114 and 116 can be formed using the same kind of insulating film, the interface between the insulating film 114 and the insulating film 116 may not be clearly confirmed. Therefore, in this embodiment mode, the interface between the insulating film 114 and the insulating film 116 is indicated by a broken line. Note that although a two-layer structure of the insulating film 114 and the insulating film 116 has been described in this embodiment mode, the present invention is not limited thereto, and for example, a single-layer structure of the insulating film 114 may be employed.

The insulating film 118 includes nitrogen. The insulating film 118 includes nitrogen and silicon. The insulating film 118 has a function of blocking oxygen, hydrogen, water, alkali metal, alkaline earth metal, or the like. By providing the insulating film 118, diffusion of oxygen from the oxide semiconductor film 108 to the outside, diffusion of oxygen contained in the insulating films 114 and 116, hydrogen from the outside to the oxide semiconductor film 108, Ingress of water and the like can be prevented. As the insulating film 118, for example, a nitride insulating film can be used. Examples of the nitride insulating film include silicon nitride, silicon nitride oxide, aluminum nitride, and aluminum nitride oxide. Note that an oxide insulating film having a blocking effect of oxygen, hydrogen, water, or the like may be provided instead of the nitride insulating film having a blocking effect of oxygen, hydrogen, water, alkali metal, alkaline earth metal, or the like. Examples of the oxide insulating film having a blocking effect of oxygen, hydrogen, water, and the like include aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, and hafnium oxynitride.

Note that various films such as the conductive film, the insulating film, and the oxide semiconductor film described above can be formed by a sputtering method or a PECVD method; however, other methods such as a thermal CVD (Chemical Vapor Deposition) method are used. May be formed. As an example of the thermal CVD method, an MOCVD (Metal Organic Chemical Deposition) method or an ALD (Atomic Layer Deposition) method may be used.

The thermal CVD method has an advantage that no defect is generated due to plasma damage because it is a film forming method that does not use plasma.

In the thermal CVD method, film formation may be performed by sending a source gas and an oxidant into the chamber at the same time, making the inside of the chamber under atmospheric pressure or reduced pressure, reacting in the vicinity of the substrate or on the substrate and depositing on the substrate. .

In addition, in the ALD method, film formation may be performed by setting the inside of the chamber to atmospheric pressure or reduced pressure, sequentially introducing source gases for reaction into the chamber, and repeating the order of introducing the gases. For example, each switching valve (also referred to as a high-speed valve) is switched to supply two or more types of source gases to the chamber in order, so that a plurality of types of source gases are not mixed with the first source gas at the same time or thereafter. An active gas (such as argon or nitrogen) is introduced, and a second source gas is introduced. When the inert gas is introduced at the same time, the inert gas becomes a carrier gas, and the inert gas may be introduced at the same time when the second raw material gas is introduced. Further, instead of introducing the inert gas, the second raw material gas may be introduced after the first raw material gas is exhausted by evacuation. The first source gas is adsorbed on the surface of the substrate to form a first layer, reacts with a second source gas introduced later, and the second layer is stacked on the first layer. As a result, a thin film is formed. By repeating this gas introduction sequence a plurality of times until the desired thickness is achieved, a thin film having excellent step coverage can be formed. Since the thickness of the thin film can be adjusted by the number of times the gas introduction sequence is repeated, precise film thickness adjustment is possible, which is suitable for manufacturing a fine FET.

The thermal CVD method such as the MOCVD method or the ALD method can form various films such as the conductive film, the insulating film, the oxide semiconductor film, and the metal oxide film of the above-described embodiment, for example, an In—Ga—ZnO film. Is used, trimethylindium, trimethylgallium, and dimethylzinc are used. Note that the chemical formula of trimethylindium is In (CH ₃ ) ₃ . The chemical formula of trimethylgallium is Ga (CH ₃ ) ₃ . The chemical formula of dimethylzinc is Zn (CH ₃ ) ₂ . Moreover, it is not limited to these combinations, Triethylgallium (chemical formula Ga (C ₂ H ₅ ) ₃ ) can be used instead of trimethylgallium, and diethylzinc (chemical formula Zn (C ₂ H ₅ ) is used instead of dimethylzinc. ₂ ) can also be used.

For example, when a hafnium oxide film is formed by a film formation apparatus using ALD, a liquid containing a solvent and a hafnium precursor compound (hafnium amide such as hafnium alkoxide or tetrakisdimethylamide hafnium (TDMAH)) is vaporized. Two kinds of gases, that is, source gas and ozone (O ₃ ) as an oxidizing agent are used. Note that the chemical formula of tetrakisdimethylamide hafnium is Hf [N (CH ₃ ) ₂ ] ₄ . Other material liquids include tetrakis (ethylmethylamide) hafnium.

For example, in the case where an aluminum oxide film is formed by a film forming apparatus using ALD, a source gas obtained by vaporizing a liquid (such as trimethylaluminum (TMA)) containing a solvent and an aluminum precursor compound, and H ₂ as an oxidizing agent. Two kinds of gases of O are used. Note that the chemical formula of trimethylaluminum is Al (CH ₃ ) ₃ . Other material liquids include tris (dimethylamido) aluminum, triisobutylaluminum, aluminum tris (2,2,6,6-tetramethyl-3,5-heptanedionate) and the like.

For example, in the case where a silicon oxide film is formed by a film formation apparatus using ALD, hexachlorodisilane is adsorbed on the film formation surface, chlorine contained in the adsorbate is removed, and an oxidizing gas (O ₂ , monoxide) Dinitrogen) radicals are supplied to react with the adsorbate.

For example, in the case where a tungsten film is formed by a film forming apparatus using ALD, an initial tungsten film is formed by repeatedly introducing WF ₆ gas and B ₂ H ₆ gas successively, and then WF ₆ gas and H _2. Gases are simultaneously introduced to form a tungsten film. Note that SiH ₄ gas may be used instead of B ₂ H ₆ gas.

For example, in the case where an oxide semiconductor film such as an In—Ga—ZnO film is formed by a film formation apparatus using ALD, In (CH ₃ ) ₃ gas and O ₃ gas are sequentially introduced and In—O is sequentially introduced. Then, Ga (CH ₃ ) ₃ gas and O ₃ gas are simultaneously introduced to form a GaO layer, and then Zn (CH ₃ ) ₂ and O ₃ gas are simultaneously introduced to form a ZnO layer. To do. Note that the order of these layers is not limited to this example. Alternatively, a mixed compound layer such as an In—Ga—O layer, an In—Zn—O layer, or a Ga—Zn—O layer may be formed by mixing these gases. Incidentally, O ₃ may be used of H _{2 O} gas obtained by bubbling with an inert gas such as Ar in place of the gas, but better to use an O ₃ gas containing no H are preferred. Further, In (C ₂ H ₅ ) ₃ gas may be used instead of In (CH ₃ ) ₃ gas. Further, Ga (C ₂ H ₅ ) ₃ gas may be used instead of Ga (CH ₃ ) ₃ gas. Alternatively, Zn (CH ₃ ) ₂ gas may be used.

<Configuration Example 2 of Semiconductor Device>
Next, a structural example different from the transistor 100 illustrated in FIGS. 6A, 6 </ b> B, and 6 </ b> C is described with reference to FIGS. In addition, when it has the function similar to the function demonstrated previously, a hatch pattern may be made the same and a code | symbol may not be attached | subjected especially.

8A is a top view of the transistor 140 that is a semiconductor device of one embodiment of the present invention, and FIG. 8B is a cross-sectional view taken along the dashed-dotted line X1-X2 in FIG. 8A. 8C corresponds to a cross-sectional view of a cross-sectional surface taken along alternate long and short dash line Y1-Y2 in FIG. 8A.

The transistor 170 includes the conductive film 104 functioning as a first gate electrode over the base material 410, the insulating film 106 over the base material 410 and the conductive film 104, the insulating film 107 over the insulating film 106, and the insulating film 107. The oxide semiconductor film 108, the insulating film 114 over the oxide semiconductor film 108, the insulating film 116 over the insulating film 114, and the conductive film 112a functioning as a source electrode electrically connected to the oxide semiconductor film 108 112b functioning as a drain electrode electrically connected to the oxide semiconductor film 108, an insulating film 114 over the oxide semiconductor film 108, an insulating film 116 over the insulating film 114, and an insulating film over the insulating film 116 A film 118, a conductive film 120a over the insulating film 118, and a conductive film 120b over the insulating film 118 are included. The insulating films 114, 116, and 118 function as a second gate insulating film of the transistor 170. In addition, the conductive film 120a is electrically connected to the conductive film 112b through the opening 142c provided in the insulating films 114, 116, and 118. In the transistor 170, the conductive film 120a functions as a pixel electrode used for a display device, for example. In the transistor 170, the conductive film 120b functions as a second gate electrode (also referred to as a back gate electrode).

8C, the conductive film 120b is connected to the conductive film 104 functioning as the first gate electrode in the openings 142a and 142b provided in the insulating films 106, 107, 114, 116, and 118. Is done. Thus, the same potential is applied to the conductive film 120b and the conductive film 104.

Note that although the opening 142a and 142b are provided and the conductive film 120b and the conductive film 104 are connected in this embodiment mode, the present invention is not limited to this. For example, a structure in which only one of the opening 142a and the opening 142b is formed and the conductive film 120b and the conductive film 104 are connected, or the conductive film 120b without the openings 142a and 142b is provided. The conductive film 104 may not be connected. Note that in the case where the conductive film 120b and the conductive film 104 are not connected to each other, different potentials can be applied to the conductive film 120b and the conductive film 104, respectively.

Further, as illustrated in FIG. 8B, the oxide semiconductor film 108 is positioned so as to face the conductive film 104 functioning as a gate electrode and the conductive film 120b functioning as a second gate electrode, It is sandwiched between conductive films functioning as two gate electrodes. The length in the channel length direction and the length in the channel width direction of the conductive film 120b functioning as the second gate electrode are longer than the length in the channel length direction and the length in the channel width direction of the oxide semiconductor film 108, respectively. The entire oxide semiconductor film 108 is covered with the conductive film 120b with the insulating films 114, 116, and 118 interposed therebetween. In addition, since the conductive film 120b functioning as the second gate electrode and the conductive film 104 functioning as the gate electrode are connected to each other through the openings 142a and 142b provided in the insulating films 106, 107, 114, 116, and 118, The side surface of the oxide semiconductor film 108 in the channel width direction is opposed to the conductive film 120b functioning as the second gate electrode with the insulating films 114, 116, and 118 interposed therebetween.

In other words, in the channel width direction of the transistor 170, the conductive film 104 functioning as the gate electrode and the conductive film 120b functioning as the second gate electrode are the insulating films 106 and 107 functioning as the gate insulating film and the second gate. Insulating films 114, 116, and 118 that function as insulating films 114, 116, and 118 that function as insulating films and connect as insulating films 106 and 107 that function as gate insulating films and insulating films 114, 116, and 118 that function as second gate insulating films The oxide semiconductor film 108 is surrounded by

With such a structure, the oxide semiconductor film 108 included in the transistor 170 can be electrically surrounded by an electric field of the conductive film 104 functioning as a gate electrode and the conductive film 120b functioning as a second gate electrode. it can. A device structure of a transistor that electrically surrounds an oxide semiconductor film in which a channel region is formed by an electric field of the gate electrode and the second gate electrode as in the transistor 170 is referred to as a surrounded channel (s-channel) structure. it can.

Since the transistor 170 has an s-channel structure, an electric field for inducing a channel can be effectively applied to the oxide semiconductor film 108 by the conductive film 104 functioning as a gate electrode. Capability is improved, and high on-current characteristics can be obtained. Further, since the on-state current can be increased, the transistor 170 can be miniaturized. Further, since the transistor 170 has a structure surrounded by the conductive film 104 functioning as a gate electrode and the conductive film 120b functioning as a second gate electrode, the mechanical strength of the transistor 170 can be increased.

The other structure of the transistor 170 is similar to that of the transistor 100 described above, and has the same effect.

In the transistor according to this embodiment, each of the above structures can be freely combined. For example, the transistor 100 illustrated in FIG. 6 can be used as a pixel transistor of the display device, and the transistor 170 illustrated in FIG. 8 can be used as a gate driver transistor of the display device.

<Method 1 for Manufacturing Semiconductor Device>
Next, a method for manufacturing the transistor 100 which is a semiconductor device of one embodiment of the present invention will be described in detail with reference to FIGS. 9 to 11 are cross-sectional views illustrating a method for manufacturing a semiconductor device.

Note that a film included in the transistor 100 (an insulating film, an oxide semiconductor film, a conductive film, or the like) is formed by a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, or a pulsed laser deposition (PLD) method. can do. Alternatively, it can be formed by a coating method or a printing method. As a film forming method, a sputtering method and a plasma enhanced chemical vapor deposition (PECVD) method are typical, but a thermal CVD method may be used. As an example of the thermal CVD method, an MOCVD (metal organic chemical deposition) method or an ALD (atomic layer deposition) method may be used.

In the thermal CVD method, the inside of a chamber is set to atmospheric pressure or reduced pressure, and a source gas and an oxidant are simultaneously sent into the chamber, reacted in the vicinity of the substrate or on the substrate, and deposited on the substrate. Thus, the thermal CVD method is a film forming method that does not generate plasma, and thus has an advantage that no defect is generated due to plasma damage.

In the ALD method, film formation is performed by setting the inside of the chamber to atmospheric pressure or reduced pressure, sequentially introducing raw material gases for reaction into the chamber, and repeating the order of introducing the gases. For example, by switching each switching valve (also referred to as a high-speed valve), two or more kinds of source gases are sequentially supplied to the chamber, and at the same time or after the first source gas so as not to mix a plurality of kinds of source gases. An inert gas (such as argon or nitrogen) is introduced, and the second source gas is introduced. When the inert gas is introduced at the same time, the inert gas becomes a carrier gas, and the inert gas may be introduced at the same time when the second raw material gas is introduced. Further, instead of introducing the inert gas, the second raw material gas may be introduced after the first raw material gas is exhausted by evacuation. The first source gas is adsorbed on the surface of the substrate to form a first monoatomic layer, and reacts with a second source gas introduced later, so that the second monoatomic layer becomes the first monoatomic layer. A thin film is formed by being stacked on the atomic layer.

By repeating this gas introduction sequence a plurality of times until the desired thickness is achieved, a thin film having excellent step coverage can be formed. Since the thickness of the thin film can be adjusted by the number of times the gas introduction sequence is repeated, precise film thickness adjustment is possible, which is suitable for manufacturing a fine transistor.

First, a conductive film is formed over the base material 410, and the conductive film is processed by a lithography process and an etching process, so that the conductive film 104 functioning as a gate electrode is formed. Next, insulating films 106 and 107 functioning as gate insulating films are formed over the conductive film 104 (see FIG. 9A).

The conductive film 104 functioning as a gate electrode can be formed by a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, or a pulsed laser deposition (PLD) method. Alternatively, it can be formed by a coating method or a printing method. As a film formation method, a sputtering method or a plasma enhanced chemical vapor deposition (PECVD) method is typical, but a thermal CVD method such as the metal organic chemical vapor deposition (MOCVD) method described above, or an atomic layer deposition ( (ALD) method may be used.

In this embodiment, a glass substrate is used as the base material 410, and a tungsten film with a thickness of 100 nm is formed by a sputtering method as the conductive film 104 functioning as a gate electrode.

The insulating films 106 and 107 functioning as gate insulating films can be formed by a sputtering method, a PECVD method, a thermal CVD method, a vacuum evaporation method, a PLD method, or the like. In this embodiment, a 400-nm-thick silicon nitride film is formed as the insulating film 106 and a 50-nm-thick silicon oxynitride film is formed as the insulating film 107 by PECVD.

Note that the insulating film 106 can have a stacked structure of silicon nitride films. Specifically, the insulating film 106 can have a three-layer structure including a first silicon nitride film, a second silicon nitride film, and a third silicon nitride film. As an example of the three-layer structure, it can be formed as follows.

As the first silicon nitride film, for example, silane having a flow rate of 200 sccm, nitrogen having a flow rate of 2000 sccm, and ammonia gas having a flow rate of 100 sccm are supplied as source gases to the reaction chamber of the PE-CVD apparatus, and the pressure in the reaction chamber is controlled to 100 Pa. Then, a power of 2000 W may be supplied using a 27.12 MHz high frequency power source so that the thickness is 50 nm.

As the second silicon nitride film, silane having a flow rate of 200 sccm, nitrogen having a flow rate of 2000 sccm, and ammonia gas having a flow rate of 2000 sccm are supplied as source gases to the reaction chamber of the PECVD apparatus, and the pressure in the reaction chamber is controlled to 100 Pa; A thickness of 300 nm may be formed by supplying 2000 W of power using a 12 MHz high frequency power source.

As the third silicon nitride film, silane having a flow rate of 200 sccm and nitrogen having a flow rate of 5000 sccm are supplied as source gases to the reaction chamber of the PECVD apparatus, the pressure in the reaction chamber is controlled to 100 Pa, and a high frequency power source of 27.12 MHz is used. Then, the power may be formed so as to have a thickness of 50 nm by supplying power of 2000 W.

Note that the substrate temperature at the time of forming the first silicon nitride film, the second silicon nitride film, and the third silicon nitride film can be 350 ° C.

When the insulating film 106 has a three-layer structure of a silicon nitride film, for example, when a conductive film containing copper (Cu) is used for the conductive film 104, the following effects can be obtained.

The first silicon nitride film can suppress diffusion of copper (Cu) element from the conductive film 104. The second silicon nitride film has a function of releasing hydrogen and can improve the withstand voltage of the insulating film functioning as a gate insulating film. The third silicon nitride film emits less hydrogen from the third silicon nitride film and can suppress diffusion of hydrogen released from the second silicon nitride film.

The insulating film 107 is formed using an insulating film containing oxygen in order to improve interface characteristics with the oxide semiconductor film 108 (more specifically, the first oxide semiconductor film 108a) to be formed later. preferable.

Next, the first oxide semiconductor film 108 a is formed over the insulating film 107. After that, a second oxide semiconductor film 108b is formed over the first oxide semiconductor film 108a (see FIG. 9B).

In this embodiment, the first oxide semiconductor film is formed by a sputtering method using an In—Ga—Zn metal oxide target (In: Ga: Zn = 3: 1: 2 (atomic ratio)). Then, the second oxidation is performed by sputtering using an In—Ga—Zn metal oxide target (In: Ga: Zn = 1: 1: 1.2 (atomic ratio)) continuously in vacuum. A stacked oxide semiconductor film is formed by forming a physical semiconductor film. Next, a mask is formed over the oxide semiconductor film of the previous layer by a lithography process, and the island-shaped oxide semiconductor film 108 is formed by processing the stacked oxide semiconductor film into a desired region.

Note that when the oxide semiconductor film 108 is formed by a sputtering method, a rare gas (typically argon), oxygen, a rare gas, and a mixed gas of oxygen are used as appropriate as the sputtering gas. In the case of a mixed gas, it is preferable to increase the oxygen gas ratio relative to the rare gas. In addition, it is necessary to increase the purity of the sputtering gas. For example, oxygen gas or argon gas used as a sputtering gas is a gas having a dew point of −40 ° C. or lower, preferably −80 ° C. or lower, more preferably −100 ° C. or lower, more preferably −120 ° C. or lower. By using it, moisture and the like can be prevented from being taken into the oxide semiconductor film 108 as much as possible.

In the case where the oxide semiconductor film 108 is formed by a sputtering method, an adsorption vacuum exhaust pump such as a cryopump is used as a chamber in the sputtering apparatus so as to remove water or the like that is an impurity for the oxide semiconductor film 108 as much as possible. It is preferable to perform high vacuum evacuation (from about 5 × 10 ⁻⁷ Pa to about 1 × 10 ⁻⁴ Pa) using Alternatively, it is preferable to combine a turbo molecular pump and a cold trap so that a gas, particularly a gas containing carbon or hydrogen, does not flow backward from the exhaust system into the chamber.

Next, a conductive film 112 functioning as a source electrode and a drain electrode is formed over the insulating film 107 and the oxide semiconductor film 108a (see FIG. 9C).

In this embodiment, a stacked film of a tungsten film with a thickness of 50 nm and an aluminum film with a thickness of 400 nm is formed as the conductive film 112 by a sputtering method. Note that although a two-layer structure of the conductive film 112 is employed in this embodiment mode, the present invention is not limited to this. For example, the conductive film 112 may have a three-layer structure of a tungsten film with a thickness of 50 nm, an aluminum film with a thickness of 400 nm, and a titanium film with a thickness of 100 nm.

Next, masks 140a and 140b are formed in desired regions over the conductive film 112 (see FIG. 9D).

In this embodiment, the masks 140a and 140b are formed by applying a photosensitive resin film and patterning the photosensitive resin film by a lithography process.

Next, the conductive film 112 and the second oxide semiconductor film 108b are processed using the etching gas 138 over the conductive film 112 and the masks 140a and 140b (see FIG. 10A).

In this embodiment, the conductive film 112 and the second oxide semiconductor film 108b are processed using a dry etching apparatus. However, the method for forming the conductive film 112 is not limited thereto, and the conductive film 112 and the second oxide semiconductor film 108b can be formed using a wet etching apparatus by using a chemical solution for the etching gas 138, for example. It may be processed. However, the conductive film 112 and the second oxide semiconductor film 108b were processed using a dry etching apparatus rather than the conductive film 112 and the second oxide semiconductor film 108b were processed using a wet etching apparatus. This is more preferable because a finer pattern can be formed.

Next, by removing the masks 140a and 140b, the conductive film 112a functioning as a source electrode over the second oxide semiconductor film 108b and the conductive film functioning as a drain electrode over the second oxide semiconductor film 108 112b. In the oxide semiconductor film 108, a first oxide semiconductor film 108a and a second oxide semiconductor film 108b having a depression are formed (see FIG. 10B).

Alternatively, a chemical solution may be applied over the second oxide semiconductor film 108b and the conductive films 112a and 112b to clean the surface (back channel side) of the second oxide semiconductor film 108b.
Examples of the cleaning method include cleaning using a chemical solution such as phosphoric acid. By cleaning with a chemical solution such as phosphoric acid, impurities attached to the surface of the second oxide semiconductor film 108b (eg, elements contained in the conductive films 112a and 112b) can be removed. Note that the cleaning is not necessarily performed, and in some cases, the cleaning may not be performed.

In addition, when the conductive films 112a and 112b are formed and / or in the cleaning step, the second oxide semiconductor film 108b includes a second region that is thinner than the first oxide semiconductor film 108a.

Next, insulating films 114 and 116 are formed over the oxide semiconductor film 108 and the conductive films 112a and 112b (see FIG. 10C).

Note that after the insulating film 114 is formed, the insulating film 116 is preferably formed continuously without being exposed to the air. After forming the insulating film 114, the insulating film 114 and the insulating film are formed by continuously forming the insulating film 116 by adjusting one or more of the flow rate, pressure, high frequency power, and substrate temperature of the source gas without opening to the atmosphere. The concentration of impurities derived from atmospheric components can be reduced at the interface 116, and oxygen contained in the insulating films 114 and 116 can be transferred to the oxide semiconductor film 108, so that the amount of oxygen vacancies in the oxide semiconductor film 108 can be reduced. Can be reduced.

For example, as the insulating film 114, a silicon oxynitride film can be formed by a PECVD method. In this case, it is preferable to use a deposition gas and an oxidation gas containing silicon as the source gas. Typical examples of the deposition gas containing silicon include silane, disilane, trisilane, and fluorinated silane. Examples of the oxidizing gas include dinitrogen monoxide and nitrogen dioxide. Further, by using a PECVD method in which the oxidizing gas with respect to the depositing gas is greater than 20 times and less than 100 times, preferably 40 or more and 80 or less, and the pressure in the processing chamber is less than 100 Pa, preferably 50 Pa or less. The film 114 is an insulating film containing nitrogen and having a small amount of defects.

In this embodiment mode, as the insulating film 114, the temperature at which the base material 410 is held is 220 ° C., silane having a flow rate of 50 sccm and dinitrogen monoxide having a flow rate of 2000 sccm are used as source gas, and the pressure in the processing chamber is 20 Pa. A silicon oxynitride film is formed using a PECVD method in which high-frequency power supplied to the plate electrode is 13.56 MHz and 100 W (power density is 1.6 × 10 ⁻² W / cm ² ).

As the insulating film 116, a substrate placed in a processing chamber evacuated by a PECVD apparatus is held at 180 ° C. or higher and 350 ° C. or lower, and a raw material gas is introduced into the processing chamber so that the pressure in the processing chamber is 100 Pa or higher and 250 Pa or lower. , more preferably not more than 200Pa than 100 Pa, the electrode provided in the processing chamber 0.17 W / cm ² or more 0.5 W / cm ² or less, more preferably 0.25 W / cm ² or more 0.35 W / cm ² or less of A silicon oxide film or a silicon oxynitride film is formed depending on conditions for supplying high-frequency power.

As the conditions for forming the insulating film 116, by supplying high-frequency power with the above power density in the reaction chamber at the above pressure, the decomposition efficiency of the source gas in plasma increases, oxygen radicals increase, and the oxidation of the source gas proceeds. Therefore, the oxygen content in the insulating film 116 is higher than the stoichiometric composition. On the other hand, in a film formed at the above substrate temperature, since the bonding force between silicon and oxygen is weak, part of oxygen in the film is released by heat treatment in a later step. As a result, an oxide insulating film containing more oxygen than that in the stoichiometric composition and from which part of oxygen is released by heating can be formed.

The step of forming the insulating film 116 is preferably performed at a temperature of 180 ° C. to 350 ° C. with a PECVD apparatus, and the temperature of the step of forming the insulating film 116 is preferably highest during the manufacturing process of the transistor 100. For example, by performing the insulating film 116 at a temperature of 350 ° C., the transistor 100 can be directly formed on a flexible printed circuit board or the like.

Note that in the formation process of the insulating film 116, the insulating film 114 serves as a protective film of the oxide semiconductor film 108. Therefore, the insulating film 116 can be formed using high-frequency power with high power density while reducing damage to the oxide semiconductor film 108.

Note that the amount of defects in the insulating film 116 can be reduced by increasing the flow rate of the deposition gas containing silicon with respect to the oxidizing gas under the deposition conditions of the insulating film 116. Typically, by ESR measurement, the spin density of a signal appearing at g = 2.001 derived from a dangling bond of silicon is less than 6 × 10 ¹⁷ spins / cm ³ , preferably 3 × 10 ¹⁷ spins / cm ³ or less. An oxide insulating layer with a small amount of defects that is preferably 1.5 × 10 ¹⁷ spins / cm ³ or less can be formed. As a result, the reliability of the transistor can be improved.

Further, heat treatment may be performed after the insulating films 114 and 116 are formed. By the heat treatment, nitrogen oxides contained in the insulating films 114 and 116 can be reduced. Further, part of oxygen contained in the insulating films 114 and 116 is moved to the oxide semiconductor film 108 by the heat treatment, so that the amount of oxygen vacancies contained in the oxide semiconductor film 108 can be reduced.

The temperature of heat treatment for the insulating films 114 and 116 is typically 150 ° C to 350 ° C inclusive. The heat treatment may be performed in an atmosphere of nitrogen, oxygen, ultra-dry air (air with a water content of 20 ppm or less, preferably 1 ppm or less, preferably 10 ppb or less), or a rare gas (such as argon or helium). Note that an electric furnace, an RTA apparatus, or the like can be used for the heat treatment in which hydrogen, water, or the like is preferably not contained in the nitrogen, oxygen, ultradry air, or the rare gas.

In this embodiment, heat treatment is performed at 350 ° C. for one hour in a nitrogen atmosphere. Note that in the step of forming the transistor 100, it is only necessary that the temperature at which the insulating film 116 is formed be the highest, and a temperature equivalent to the temperature at which the insulating film 116 is formed may be performed in a different step.

Next, an oxide conductive film 131 is formed over the insulating film 116 (see FIG. 10D).

The oxide conductive film 131 includes oxygen and a metal (at least one selected from indium, zinc, titanium, aluminum, tungsten, tantalum, and molybdenum).

Examples of the oxide conductive film 131 include a tantalum oxynitride film, a titanium oxide film, an indium tin oxide (hereinafter also referred to as ITO) film, an aluminum oxide film, and an oxide semiconductor film (for example, an IGZO film (In: Ga: Zn = 1: 4: 5 (atomic ratio)) and the like. The oxide conductive film 131 can be formed by a sputtering method. The thickness of the oxide conductive film 131 is preferably 1 nm to 20 nm, or 2 nm to 10 nm. In this embodiment, indium tin oxide (Indium Tin SiO ₂ Doped Oxide: hereinafter referred to as an ITSO film) to which silicon oxide with a thickness of 5 nm is added is used as the oxide conductive film 131.

Next, oxygen 139 is added to the insulating films 114 and 116 and the oxide semiconductor film 108 through the oxide conductive film 131 (see FIG. 11A).

As a method for adding oxygen 139 to the insulating films 114 and 116 and the oxide semiconductor film 108 through the oxide conductive film 131, an ion doping method, an ion implantation method, a plasma treatment method, or the like can be given. In addition, when adding oxygen 139, oxygen 139 can be effectively added to the insulating films 114 and 116 and the oxide semiconductor film 108 by applying a bias to the substrate side. As the bias, for example, the power density may be 1 W / cm ² or more and 5 W / cm ² or less. By providing the oxide conductive film 131 over the insulating film 116 and adding oxygen, the oxide conductive film 131 functions as a protective film that suppresses release of oxygen from the insulating film 116. Therefore, more oxygen can be added to the insulating films 114 and 116 and the oxide semiconductor film 108.

Next, the oxide conductive film 131 is removed with an etchant 142 (see FIG. 11B).

As a method for removing the oxide conductive film 131, a dry etching method, a wet etching method, a method in which the dry etching method and the wet etching method are combined, or the like can be given. In the case of the dry etching method, the etchant 142 is an etching gas, and in the case of the wet etching method, the etchant 142 is a chemical solution. In this embodiment, the oxide conductive film 131 is removed by a wet etching method.

Next, an insulating film 118 is formed over the insulating film 116 (see FIG. 11C).

Note that heat treatment is performed before the insulating film 118 is formed or after the insulating film 118 is formed, so that excess oxygen contained in the insulating films 114 and 116 is diffused into the oxide semiconductor film 108. Oxygen deficiency can be compensated. Alternatively, when the insulating film 118 is formed by heating, excess oxygen contained in the insulating films 114 and 116 can be diffused into the oxide semiconductor film 108 to fill oxygen vacancies in the oxide semiconductor film 108. .

In the case where the insulating film 118 is formed by a PECVD method, it is preferable that the substrate temperature be 180 ° C. or higher and 350 ° C. or lower because a dense film can be formed.

For example, in the case where a silicon nitride film is formed as the insulating film 118 by a PECVD method, it is preferable to use a deposition gas containing silicon, nitrogen, and ammonia as a source gas. By using a small amount of ammonia as compared with nitrogen, ammonia is dissociated in the plasma and active species are generated. The active species breaks the bond between silicon and hydrogen contained in the deposition gas containing silicon and the triple bond of nitrogen. As a result, the bonding between silicon and nitrogen is promoted, the bonding between silicon and hydrogen is small, the defects are few, and a dense silicon nitride film can be formed. On the other hand, when the amount of ammonia with respect to nitrogen is large, decomposition of the deposition gas containing silicon and nitrogen does not proceed, and silicon and hydrogen bonds remain, resulting in an increased defect and a rough silicon nitride film. End up. For these reasons, in the source gas, the flow rate ratio of nitrogen to ammonia is preferably 5 or more and 50 or less and 10 or more and 50 or less.

In this embodiment, as the insulating film 118, a silicon nitride film with a thickness of 50 nm is formed from a source gas of silane, nitrogen, and ammonia using a PECVD apparatus. The flow rates are 50 sccm for silane, 5000 sccm for nitrogen, and 100 sccm for ammonia. The processing chamber pressure is 100 Pa, the substrate temperature is 350 ° C., and high frequency power of 1000 W is supplied to the parallel plate electrodes using a high frequency power source of 27.12 MHz. PECVD apparatus is a PECVD apparatus of a parallel plate type electrode area is 6000 cm ^2, which is in terms 1.7 × ¹⁰ -1 W / cm ² to the power per unit area power supplied (power density).

Through the above steps, the transistor 100 illustrated in FIG. 6 can be formed.

<Method 2 for Manufacturing Semiconductor Device>
Next, a method for manufacturing the transistor 170 which is one embodiment of the present invention will be described in detail with reference to FIGS. FIG. 12 is a cross-sectional view illustrating a method for manufacturing a semiconductor device. 12A, 12C, 12E, and 12G are cross-sectional views in the channel length direction during the manufacture of the transistor 170. FIGS. 12B, 12D, 12F, and 12H are transistors. It is sectional drawing of the channel width direction in the middle of preparation of 170. FIG.

First, steps similar to those for manufacturing the transistor 100 described above (steps illustrated in FIGS. 9 to 11) are performed, and the conductive film 104, the insulating films 106 and 107, the oxide semiconductor film 108, and the conductive film are formed over the base 410. 112a and 112b and insulating films 114, 116, and 118 are formed (see FIGS. 12A and 12B).

Next, a mask is formed over the insulating film 118 by a lithography process, and an opening 142 c is formed in a desired region of the insulating films 114, 116, and 118. Further, a mask is formed over the insulating film 118 by a lithography process, and openings 142 a and 142 b are formed in desired regions of the insulating films 106, 107, 114, 116, and 118. Note that the opening 142c is formed so as to reach the conductive film 112b. The openings 142a and 142b are formed so as to reach the conductive film 104, respectively (see FIGS. 12C and 12D).

Note that the openings 142a and 142b and the opening 142c may be formed in the same process or in different processes. In the case where the openings 142a and 142b and the opening 142c are formed in the same process, for example, a gray-tone mask or a half-tone mask can be used. Further, the openings 142a and 142b may be formed in a plurality of times. For example, the insulating films 106 and 107 are processed, and then the insulating films 114, 116, and 118 are processed.

Next, a conductive film 120 is formed over the insulating film 118 so as to cover the openings 142a, 142b, and 142c (see FIGS. 12E and 12F).

For the conductive film 120, for example, a material containing one kind selected from indium (In), zinc (Zn), and tin (Sn) can be used. In particular, the conductive film 120 includes indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide (ITO), A light-transmitting conductive material such as indium zinc oxide or indium tin oxide to which silicon oxide is added (ITSO film) can be used. Further, the conductive film 120 can be formed by, for example, a sputtering method. In this embodiment, an ITSO film with a thickness of 110 nm is formed by a sputtering method.

Next, a mask is formed over the conductive film 120 by a lithography process, and the conductive film 112 is processed into a desired shape, so that the conductive films 120a and 120b are formed (see FIGS. 12G and 12H).

Examples of a method for forming the conductive films 120a and 120b include a dry etching method, a wet etching method, or a method in which the dry etching method and the wet etching method are combined. In this embodiment, the conductive film 120 is processed into the conductive films 120a and 120b by a wet etching method.

Through the above process, the transistor 170 illustrated in FIG. 8 can be manufactured.

<Configuration Example 2 of Semiconductor Device>
FIG. 16A is a cross-sectional view of a transistor 100B that can be used for the light-emitting panel of one embodiment of the present invention.

The transistor 100B includes an oxide semiconductor film 108c. The shape of the oxide semiconductor film 108c is different from that of the oxide semiconductor film 108b included in the transistor 100.

<Configuration Example 3 of Semiconductor Device>
FIG. 16B is a cross-sectional view of a transistor 100C that can be used for the light-emitting panel of one embodiment of the present invention.

The transistor 100C includes one oxide semiconductor film 108.

<Configuration Example 4 of Semiconductor Device>
FIG. 16C is a cross-sectional view of a transistor 100D that can be used for the light-emitting panel of one embodiment of the present invention.

The transistor 100D includes an oxide semiconductor film 108a and an oxide semiconductor film 108b that is thinner than the oxide semiconductor film 108a.

<Structure Example 5 of Semiconductor Device>
FIG. 16D is a cross-sectional view of a transistor 100E that can be used for the light-emitting panel of one embodiment of the present invention.

The transistor 100E includes the insulating film 119 between the insulating film 118 and the oxide semiconductor film 108c.

Note that this embodiment can be combined with any of the other embodiments described in this specification as appropriate.

For example, in this specification and the like, when X and Y are explicitly described as being connected, X and Y are electrically connected, and X and Y are functional. And the case where X and Y are directly connected are disclosed in this specification and the like. Therefore, it is not limited to a predetermined connection relationship, for example, the connection relationship shown in the figure or text, and anything other than the connection relation shown in the figure or text is also described in the figure or text.

Here, X and Y are assumed to be objects (for example, devices, elements, circuits, wirings, electrodes, terminals, conductive films, layers, etc.).

As an example of the case where X and Y are directly connected, an element that enables electrical connection between X and Y (for example, a switch, a transistor, a capacitor, an inductor, a resistor, a diode, a display, etc.) Element, light emitting element, load, etc.) are not connected between X and Y, and elements (for example, switches, transistors, capacitive elements, inductors) that enable electrical connection between X and Y X and Y are not connected via a resistor element, a diode, a display element, a light emitting element, a load, or the like.

As an example of the case where X and Y are electrically connected, an element (for example, a switch, a transistor, a capacitive element, an inductor, a resistance element, a diode, a display, etc.) that enables electrical connection between X and Y is shown. More than one element, light emitting element, load, etc.) can be connected between X and Y. Note that the switch has a function of controlling on / off. That is, the switch is in a conductive state (on state) or a non-conductive state (off state), and has a function of controlling whether or not to pass a current. Alternatively, the switch has a function of selecting and switching a path through which a current flows. Note that the case where X and Y are electrically connected includes the case where X and Y are directly connected.

As an example of the case where X and Y are functionally connected, a circuit (for example, a logic circuit (an inverter, a NAND circuit, a NOR circuit, etc.) that enables a functional connection between X and Y, signal conversion, etc. Circuit (DA conversion circuit, AD conversion circuit, gamma correction circuit, etc.), potential level conversion circuit (power supply circuit (boost circuit, step-down circuit, etc.), level shifter circuit that changes signal potential level, etc.), voltage source, current source, switching Circuit, amplifier circuit (circuit that can increase signal amplitude or current amount, operational amplifier, differential amplifier circuit, source follower circuit, buffer circuit, etc.), signal generation circuit, memory circuit, control circuit, etc.) One or more can be connected between them. As an example, even if another circuit is interposed between X and Y, if the signal output from X is transmitted to Y, X and Y are functionally connected. To do. Note that the case where X and Y are functionally connected includes the case where X and Y are directly connected and the case where X and Y are electrically connected.

In addition, when it is explicitly described that X and Y are electrically connected, a case where X and Y are electrically connected (that is, there is a separate connection between X and Y). And X and Y are functionally connected (that is, they are functionally connected with another circuit between X and Y). And the case where X and Y are directly connected (that is, the case where another element or another circuit is not connected between X and Y). It shall be disclosed in the document. In other words, when it is explicitly described that it is electrically connected, the same contents as when it is explicitly described only that it is connected are disclosed in this specification and the like. It is assumed that

Note that for example, the source (or the first terminal) of the transistor is electrically connected to X through (or not through) Z1, and the drain (or the second terminal or the like) of the transistor is connected to Z2. Through (or without), Y is electrically connected, or the source (or the first terminal, etc.) of the transistor is directly connected to a part of Z1, and another part of Z1 Is directly connected to X, and the drain (or second terminal, etc.) of the transistor is directly connected to a part of Z2, and another part of Z2 is directly connected to Y. Then, it can be expressed as follows.

For example, “X and Y, and the source (or the first terminal or the like) and the drain (or the second terminal or the like) of the transistor are electrically connected to each other. The drain of the transistor (or the second terminal, etc.) and the Y are electrically connected in this order. ” Or “the source (or the first terminal or the like) of the transistor is electrically connected to X, the drain (or the second terminal or the like) of the transistor is electrically connected to Y, and X or the source ( Or the first terminal or the like, the drain of the transistor (or the second terminal, or the like) and Y are electrically connected in this order. Or “X is electrically connected to Y through the source (or the first terminal) and the drain (or the second terminal) of the transistor, and X is the source of the transistor (or the first terminal). Terminal, etc.), the drain of the transistor (or the second terminal, etc.), and Y are provided in this connection order. By using the same expression method as in these examples and defining the order of connection in the circuit configuration, the source (or the first terminal, etc.) and the drain (or the second terminal, etc.) of the transistor are separated. Apart from that, the technical scope can be determined.

Alternatively, as another expression method, for example, “a source (or a first terminal or the like of a transistor) is electrically connected to X through at least a first connection path, and the first connection path is The second connection path does not have a second connection path, and the second connection path includes a transistor source (or first terminal or the like) and a transistor drain (or second terminal or the like) through the transistor. The first connection path is a path through Z1, and the drain (or the second terminal, etc.) of the transistor is electrically connected to Y through at least the third connection path. The third connection path is connected and does not have the second connection path, and the third connection path is a path through Z2. " Or, “the source (or the first terminal or the like) of the transistor is electrically connected to X via Z1 by at least a first connection path, and the first connection path is a second connection path. The second connection path has a connection path through the transistor, and the drain (or the second terminal, etc.) of the transistor is at least connected to Z2 by the third connection path. , Y, and the third connection path does not have the second connection path. Or “the source of the transistor (or the first terminal or the like) is electrically connected to X through Z1 by at least a first electrical path, and the first electrical path is a second electrical path Does not have an electrical path, and the second electrical path is an electrical path from the source (or first terminal or the like) of the transistor to the drain (or second terminal or the like) of the transistor; The drain (or the second terminal or the like) of the transistor is electrically connected to Y through Z2 by at least a third electrical path, and the third electrical path is a fourth electrical path. The fourth electrical path is an electrical path from the drain (or second terminal or the like) of the transistor to the source (or first terminal or the like) of the transistor. can do. Using the same expression method as those examples, by defining the connection path in the circuit configuration, the source (or the first terminal or the like) of the transistor and the drain (or the second terminal or the like) are distinguished. The technical scope can be determined.

In addition, these expression methods are examples, and are not limited to these expression methods. Here, it is assumed that X, Y, Z1, and Z2 are objects (for example, devices, elements, circuits, wirings, electrodes, terminals, conductive films, layers, and the like).

In addition, even when the components shown in the circuit diagram are electrically connected to each other, even when one component has the functions of a plurality of components. There is also. For example, in the case where a part of the wiring also functions as an electrode, one conductive film has both the functions of the constituent elements of the wiring function and the electrode function. Therefore, the term “electrically connected” in this specification includes in its category such a case where one conductive film has functions of a plurality of components.

C1 (i) Electrode C2 (j) Electrode CON1 Connection part CON2 Connection part L1 Line L2 Line M0 Transistor M6 Transistor SD6 Drive circuit FPC1 Flexible printed circuit board FPC2 Flexible printed circuit board FPC3 Flexible printed circuit board FPC4 Flexible printed circuit board 10 Image signal 11 Selection signal 12 Control signal 13 signal 14 signal 100 transistor 100B transistor 100C transistor 100D transistor 100E transistor 104 conductive film 106 insulating film 107 insulating film 108 oxide semiconductor film 108a oxide semiconductor film 108b oxide semiconductor film 108c oxide semiconductor film 112 conductive film 112a conductive Film 112b Conductive film 114 Insulating film 116 Insulating film 118 Insulating film 119 Insulating film 120 Conductive film 120a Conductive film 120b Conductive film 131 Oxide conductive film 138 Etching gas 139 Oxygen 140 Transistor 140a Mask 140b Mask 142 Etchant 142a Opening 142b Opening 142c Opening 150 Transistor 170 Transistor 400 Light emitting panel 402 Segment 402B Segment 410 Base material 419 Terminal portion 421 Insulating film 428a Opening 428b Opening 450 Light-emitting element 450P Optical element 451 Electrode 452 Electrode 470 Base material 479 Terminal panel 600 Display panel 600M Display module 600MB Display module 600MT Display module 600T Display panel 602 Pixel 602B Subpixel 602G Subpixel 602R Subpixel 602Y Subpixel 605 Sealing material 610 Base material 611 Wiring 619 Terminal 621 Insulating film 650R Liquid crystal element 651 Electrode 652 Electrode 653 layer 670 substrate 670P optical element 671 insulating film 675 proximity sensor 3000 display 3000B display device 3001 housing 3001B housing 3100 calculation unit 3110 storing unit 3500 driver 3540 emitting panel driver 3560 display panel drive unit

Claims (9)

A first connection portion, a segment circuit, a light emitting element, a first base material, and a second base material;
The segment circuit is electrically connected to the first connection portion,
The light emitting element is electrically connected to the first connection portion,
The first base material is provided with the segment circuit,
The second base material is provided with the light emitting element. The segment circuit is electrically connected to a first power line,
The segment circuit is electrically connected to a selection line,
The segment circuit is electrically connected to the signal line,
The selection line has a function of supplying a selection signal,
The signal line has a function of supplying a control signal,
The segment circuit has a function of supplying power to the first connection unit,
The segment circuit has a function of controlling the power based on the selection signal and the control signal,
The light emitting element includes a first electrode and a second electrode,
The first electrode is electrically connected to the first connecting portion;
The second electrode is electrically connected to a second power line;
The first electrode is supplied with the power,
The light emitting panel in which the second power supply line supplies a potential different from that of the first power supply line. A plurality of the segment circuits;
The plurality of segment circuits are arranged in a matrix on the first base material,
The selection line is electrically connected to the plurality of segment circuits arranged in a row direction,
The light emitting panel according to claim 1, wherein the signal line is electrically connected to the plurality of segment circuits arranged in a column direction intersecting with the row direction. The second base material includes a region overlapping the first base material,
The second base material is disposed between the light emitting element and the first base material,
The second substrate includes an opening,
The light emitting panel according to claim 1, wherein the first connection portion includes a first wiring disposed in the opening. A second connecting portion electrically connected to the first power line;
The segment circuit is electrically connected to the second connection portion,
4. The light-emitting panel according to claim 1, wherein the first power line and the second power line are disposed on the second base material. 5. The segment circuit includes a first transistor, a second transistor, and a capacitor,
The first transistor has a gate electrically connected to the selection line, a first electrode electrically connected to the signal line,
The second transistor has a gate electrically connected to the second electrode of the first transistor, a first electrode electrically connected to the first connection portion, and a second electrode connected to the second electrode. Electrically connected to the first power line,
The capacitor element has a first electrode electrically connected to a gate of the second transistor, and a second electrode electrically connected to a second electrode of the second transistor. The light-emitting panel according to claim 4. The segment circuit includes a plurality of transistors,
The light emitting panel according to claim 1, wherein the plurality of transistors include a semiconductor film that can be formed in the same process. The segment circuit includes a plurality of transistors,
The light emitting panel according to claim 1, wherein the plurality of transistors include an oxide semiconductor film that can be formed in the same process. A light emitting panel according to any one of claims 1 to 7,
A display panel having a region overlapping with the light-emitting panel,
The display panel includes a plurality of pixels in a region overlapping with one of the light emitting elements. A display module according to claim 8;
A drive unit electrically connected to the display module;
The drive unit has a function of supplying an image signal, the selection signal, and the control signal,
The display panel is supplied with the image signal,
The light emitting panel is a display device to which the selection signal and the control signal are supplied.

Images