JP2011195870A - Film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film forming method for suppressing a material except for the film forming material from mixing into the layer to be formed and preventing decrease in the performance of a light emitting element.SOLUTION: The film forming method comprises: disposing a first substrate having an absorption layer formed on one surface of the substrate and having a material layer containing a film forming material formed, as an outermost surface of the one surface of the substrate, on the absorption layer, and a second substrate having a base layer formed as an outermost surface of the substrate surface where a film is to be formed, in such a manner that the one surface of the first substrate opposes to the surface of the second substrate where a film is to be formed; and heat treating the first substrate from the other surface side so as to form a layer of the film forming material on the base layer by using the film forming material included in the heated material layer. In the method, the same material is used for the main component of the film forming material layer and for the main component of the base layer.

Description

The present invention relates to a film forming method for forming a film on a substrate.

In recent years, research and development of light-emitting elements using electroluminescence (hereinafter referred to as EL) have been actively conducted. The basic structure of these light-emitting elements is such that a layer containing a light-emitting substance (hereinafter referred to as an EL layer) is sandwiched between a pair of electrodes. By applying voltage to this element, light emission from the light-emitting substance can be obtained.

The EL layer included in the light-emitting element has at least a light-emitting layer. In addition, the EL layer can have a stacked structure including a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like in addition to the light-emitting layer.

Further, EL materials for forming the EL layer are roughly classified into low molecular (monomer) materials and high molecular (polymer) materials. In general, a low molecular weight material is often formed using a vapor deposition method, and a high molecular weight material is often formed using an ink jet method or a spin coat method.

A vapor deposition apparatus used in the case of the vapor deposition method includes a substrate holder for installing a substrate, a crucible (or vapor deposition boat) enclosing a vapor deposition material (here, EL material), a heater for heating the EL material in the crucible, It has a shutter for preventing the diffusion of the EL material to be sublimated, and the EL material heated by the heater is sublimated to form a film on the substrate.

However, in practice, in order to uniformly form a film, it is necessary to rotate the deposition target substrate and to keep the distance between the substrate and the crucible more than a certain value. In addition, when performing painting through a shadow mask such as a metal mask using a plurality of EL materials, the interval between the pixels is designed wide, and the width of the partition made of an insulator provided between the pixels is widened. It will be necessary. For this reason, high definition (increase in the number of pixels) of a light emitting device including a light emitting element and miniaturization of each display pixel pitch accompanying downsizing are major issues. At the same time, it is required to improve productivity and reduce costs.

On the other hand, a method of forming an EL layer of a light emitting element by thermal transfer has been proposed (see Patent Document 1). Patent Document 1 describes an evaporation source substrate having a material layer composed of a mixture of an evaporation material and a binder material. By heat-treating such a deposition source substrate, a deposition material layer can be formed on the deposition target substrate.

JP 2008-291352 A

In the method of forming a deposition material on a deposition target substrate by heat-treating the deposition source substrate as in the above-described thermal transfer, in order to deposit the deposition material at a high rate, the deposition source substrate and the deposition target are formed. The distance between the substrates needs to be very small. Therefore, during the heat treatment, the temperature of the base layer on the deposition substrate rapidly increases, and the vapor deposition material and the base layer material may be mixed in the vapor deposition material layer formed on the base layer. is there.

As described above, the EL layer can have a stacked structure of layers having different functions, such as a light-emitting layer and a hole injection layer. In this stacked structure, an EL material that forms another layer in one layer is used. When mixed, the performance such as the light emission efficiency and life of the light emitting element may deteriorate.

In view of the above, an object of one embodiment of the present invention is to provide a film formation method in which a material other than a film formation material is prevented from being mixed into a film formation layer to prevent deterioration in performance of the light-emitting element.

The above-described problem is that at least an absorption layer and a material layer are formed on one surface, a deposition substrate having the material layer on the outermost surface of the one surface, and an underlayer on the outermost surface of the deposition surface Using the deposition substrate, heat treatment is performed from the other side of the deposition substrate so that the absorption layer absorbs energy to generate heat, and deposition is performed with the deposition material included in the heated material layer. This is a film formation method in which a film formation material layer is formed over the base layer of the substrate, and can be solved by a film formation method using the same substance as the main component of the base layer and the main component of the film formation material layer.

One embodiment of the present invention includes an absorption layer formed over one surface of a substrate, and a material layer including a film formation material formed over the absorption layer and formed on the outermost surface of one surface of the substrate. One surface of the first substrate having the surface and the film formation surface of the second substrate having the base layer formed on the outermost surface of the film formation surface of the substrate are arranged to face each other, and the other surface of the first substrate In this film forming method, a heat treatment is performed from the surface side of the substrate so that the absorption layer absorbs energy to generate heat, and a film formation material included in the heated material layer forms a film formation material layer on the base layer. In other words, the same material is used for the main component of the film forming material layer and the main component of the base layer.

In one embodiment of the present invention, an absorption layer formed over one surface of the substrate, and a material layer including a film formation material formed over the absorption layer and formed on the outermost surface of the one surface of the substrate And the first substrate having a film formation surface of the second substrate having a base layer formed on the outermost surface of the film formation surface of the substrate facing each other. By performing heat treatment from the other surface side of the film, the absorption layer absorbs energy to generate heat, and a film formation material included in the heated material layer forms a film formation material layer on the base layer This is a film forming method in which the base layer is formed of a substance used for the film forming material layer.

Another embodiment of the present invention is a deposition method in which the absorption layer is formed in an island shape or a stripe shape in the above structure.

Another embodiment of the present invention is a deposition method in which the material layer is formed in an island shape or a stripe shape in the above structure.

Another embodiment of the present invention is a film formation method in which a reflective layer having an opening is formed between the first substrate and the absorption layer in the above structure.

Another embodiment of the present invention is a film formation method in which, in the above structure, a heat insulating layer having an opening in a position overlapping with the opening of the reflective layer is formed between the reflective layer and the absorption layer.

Another embodiment of the present invention is a deposition method in which a protective layer is formed between an absorption layer and a material layer in the above structure.

Another embodiment of the present invention is the above structure, in which the material layer is formed by a vapor deposition method, a sputtering method, a spin coating method, a printing method, a droplet discharge method, a spray method, a dropping method, an ink jet method, a nozzle printing method, or a dispensing method. Is a film forming method formed on the absorption layer.

Further, according to one embodiment of the present invention, in the above structure, the heat treatment is performed by irradiating light from the other surface side of the first substrate using a light source and heating the absorption layer by absorbing light. This is a film forming method to be used.

Another embodiment of the present invention is a film formation method using the laser oscillator, the flash lamp, or the halogen lamp as a light source in the above structure.

According to one embodiment of the present invention, a film formation method can be provided in which a material other than a film formation material is prevented from being mixed into a layer to be formed, and deterioration in performance of the light-emitting element is prevented.

4A and 4B illustrate a film formation method of one embodiment of the present invention. 4A and 4B illustrate a film formation method of one embodiment of the present invention. 4A and 4B illustrate a film formation method of one embodiment of the present invention. 3A and 3B illustrate a light-emitting element of an example. FIG. 10 shows voltage-luminance characteristics of the light-emitting element 1 and the comparative light-emitting element 2. FIG. 11 shows luminance-current efficiency characteristics of the light-emitting element 1 and the comparative light-emitting element 2; FIG. 6 shows emission spectra of the light-emitting element 1 and the comparative light-emitting element 2. FIG. 9 shows results of reliability tests of the light-emitting element 1 and the comparative light-emitting element 2;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be 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.

(Embodiment 1)
In this embodiment, a film formation method of one embodiment of the present invention will be described. In this embodiment, the case where an EL layer of a light-emitting element is formed using the film formation method of one embodiment of the present invention will be described with reference to FIGS. In this embodiment, the EL layer of the light-emitting element includes a hole-transport layer and a light-emitting layer, and the light-emitting layer is formed over the hole-transport layer using the film formation method of one embodiment of the present invention. The case will be described. In this embodiment, a case where heat treatment is performed using a light source will be described. 1A1 is a perspective view illustrating a deposition substrate used in the deposition method of one embodiment of the present invention, and FIG. 1A2 illustrates a deposition target substrate used in the deposition method of one embodiment of the present invention. FIGS. 1B and 1C are perspective views illustrating a concept of a film formation method of one embodiment of the present invention.

In FIG. 1A1, an absorption layer 103 is formed over one surface of a first substrate 101 which is a supporting substrate. In addition, a material layer 105 containing a film formation material is formed over the absorption layer 103. In FIG. 1A 2, the base layer 109 is formed over one surface of the second substrate 107.

A method for manufacturing the deposition substrate illustrated in FIG. 1A1 will be described.

First, the absorption layer 103 is formed on one surface of the first substrate 101. The first substrate 101 is a support substrate such as an absorption layer or a material layer, and is a substrate that transmits light used for forming a light-emitting layer over a deposition target substrate. Therefore, the first substrate 101 is preferably a substrate with high light transmittance. Specifically, when lamp light or laser light is used to form the light-emitting layer, it is preferable to use a substrate that transmits the light as the first substrate 101. As the first substrate 101, for example, a glass substrate, a quartz substrate, a plastic substrate containing an inorganic material, or the like can be used.

The absorption layer 103 is a layer that absorbs light irradiated to heat the material layer 105 and converts it into heat. The absorption layer 103 is preferably formed of a material having a low reflectance of 70% or less with respect to the irradiated light and a high absorption rate. Moreover, it is preferable that the absorption layer 103 is formed of a material having excellent heat resistance so that the absorption layer 103 does not change by heat. As a material that can be used for the absorption layer 103, for example, a metal nitride such as titanium nitride, tantalum nitride, molybdenum nitride, tungsten nitride, chromium nitride, or manganese nitride, molybdenum, titanium, tungsten, carbon, or the like can be used. preferable.

The absorption layer 103 can be formed using various methods. For example, the absorption layer 103 can be formed by a sputtering method using a target such as molybdenum, tantalum, titanium, or tungsten, or a target using an alloy thereof. The absorbing layer 103 is not limited to a single layer, and may be composed of a plurality of layers.

The thickness of the absorption layer 103 is preferably a thickness that does not transmit irradiated light. Although it varies depending on the material, the film thickness is preferably 100 nm or more and 2 μm or less. In particular, by setting the thickness of the absorption layer 103 to 100 nm or more and 600 nm or less, it is possible to efficiently absorb irradiated light and generate heat.

Note that the absorption layer 103 may transmit a part of the irradiation light as long as the deposition material included in the material layer 105 is heated to the sublimation temperature. Note that a material that does not decompose even when irradiated with light is preferably used for the material layer 105 when part of the irradiated light is transmitted.

Next, the material layer 105 including at least a film formation material is formed over the absorption layer 103. The material layer 105 is a layer formed including a film formation material to be formed over the base layer 109 formed over the second substrate 107. For the substance that is a main component of the deposition material included in the material layer 105, the same substance as the main component of the base layer 109 is used.

As the material layer 105, one kind of film forming material may be used, or two or more kinds of film forming materials may be used. The material layer 105 may be a single layer or a plurality of layers may be stacked.

The material layer 105 is formed by various methods. For example, a wet coating method such as spin coating, spray coating, ink jet, dip coating, casting, die coating, roll coating, blade coating, bar coating, gravure coating, nozzle printing or printing Can be used. Alternatively, a dry method such as a vacuum evaporation method or a sputtering method can be used.

In the case where the material layer 105 is formed by a wet method, a desired film forming material may be dissolved or dispersed in a solvent to adjust a solution or a dispersion. The solvent is not particularly limited as long as it can dissolve or disperse the film forming material and does not react with the film forming material. For example, halogen solvents such as chloroform, tetrachloromethane, dichloromethane, 1,2-dichloroethane, or chlorobenzene, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, n-propyl methyl ketone, or cyclohexanone, benzene, toluene, or Aromatic solvents such as xylene, ethyl acetate, n-propyl acetate, n-butyl acetate, ethyl propionate, γ-butyrolactone, ester solvents such as diethyl carbonate, ether solvents such as tetrahydrofuran or dioxane, dimethylformamide Alternatively, an amide solvent such as dimethylacetamide, dimethyl sulfoxide, hexane, water, or the like can be used. Moreover, you may mix and use multiple types of these solvents. By using the wet method, the utilization efficiency of the material can be increased, and the manufacturing cost can be reduced.

In this embodiment mode, a light-emitting layer is formed over a hole-transport layer of a light-emitting element formed over a deposition target substrate; Use compounds.

As the light-emitting substance, for example, a fluorescent compound that emits fluorescence or a phosphorescent compound that emits phosphorescence can be used.

As the light-emitting substance, the following phosphorescent compounds can be used. For example, bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) tetrakis (1-pyrazolyl) borate (abbreviation: FIr6), bis [2- (4 ′, 6 '-Difluorophenyl) pyridinato-N, C ^2' ] iridium (III) picolinate (abbreviation: FIrpic), bis [2- (3 ', 5'-bistrifluoromethylphenyl) pyridinato-N, C ^2' ] iridium ( III) Picolinate (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) acetylacetonate (abbreviation: FIracac), tris (2-phenylpyridinato-) iridium (III) (abbreviation: Ir _(ppy) 3), bis (2-phenylpyridinato ) Iridium (III) acetylacetonate _{(abbreviation: Ir (ppy) 2 (acac} )), bis (benzo [h] quinolinato) iridium (III) acetylacetonate _{(abbreviation: Ir (bzq) 2 (acac} )), bis (2,4-diphenyl-1,3-oxazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (dpo) ₂ (acac)), bis [2- (4′-perfluorophenyl) Phenyl) pyridinato] iridium (III) acetylacetonate (abbreviation: Ir (p-PF-ph) ₂ (acac)), bis (2-phenylbenzothiazolate-N, C ^{2 ′} ) iridium (III) acetylacetate inert _{(abbreviation: Ir (bt) 2 (acac} )), bis [2- (2'-benzo [4, 5-alpha] thienyl) Pirijina -N, C ^{3 ']} iridium (III) acetylacetonate _{(abbreviation: Ir (btp) 2 (acac} )), bis (1-phenylisoquinolinato--N, C ^2') iridium (III) acetylacetonate ( Abbreviations: Ir (piq) ₂ (acac)), (acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (abbreviation: Ir (Fdpq) ₂ (acac)), ( Acetylacetonato) bis (2,3,5-triphenylpyrazinato) iridium (III) (abbreviation: Ir (tppr) ₂ (acac)), 2,3,7,8,12,13,17,18 -Octaethyl-21H, 23H-porphyrin platinum (II) (abbreviation: PtOEP), tris (acetylacetonato) (monophenanthroline) tellurium Bium (III) (abbreviation: Tb (acac) ₃ (Phen)), tris (1,3-diphenyl-1,3-propanedionate) (monophenanthroline) europium (III) (abbreviation: Eu (DBM) ₃ ( Phen)), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: Eu (TTA) ₃ (Phen)) and the like.

Further, as the luminescent substance, the following fluorescent compounds can be used. For example, N, N′-bis [4- (9H-carbazol-9-yl) phenyl] -N, N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4- (9H-carbazole- 9-yl) -4 '-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (9H-carbazol-9-yl) -4'-(9,10-diphenyl-2- Anthryl) triphenylamine (abbreviation: 2YGAPPA), N, 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2 , 5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4- (10-phenyl-9-anthryl) -4 '-(9-phenyl-9H-ca Basol-3-yl) triphenylamine (abbreviation: PCBAPA), N, N ″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) bis [N, N ′, N ′ -Triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N, 9-diphenyl-N- [4- (9,10-diphenyl-2-anthryl) phenyl] -9H-carbazol-3-amine ( Abbreviation: 2PCAPPA), N- [4- (9,10-diphenyl-2-anthryl) phenyl] -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N, N , N ′, N ′, N ″, N ″, N ′ ″, N ′ ″-octaphenyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC) ), Coumarin 30,9,10-diphenyl-2- [N-phenyl-N- (9-phenyl-9H-carbazol-3-yl) amino] anthracene (abbreviation: 2PCAPA), N- [9,10-bis (1,1′-biphenyl-2-yl) -2-anthryl] -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N- (9,10-diphenyl-2-anthryl) -N, N ', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis (1,1'-biphenyl-2-yl) -2-anthryl]- N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis (1,1′-biphenyl-2-yl) -N- [4- (9H-carbazo -9-yl) phenyl] -N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N, 9-triphenylanthracen-9-amine (abbreviation: DPhAPhA) coumarin 545T, N, N'- Diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12-bis (1,1′-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), 2- (2- {2- [ 4- (dimethylamino) phenyl] ethenyl} -6-methyl-4H-pyran-4-ylidene) propanedinitrile (abbreviation: DCM1), 2- {2-methyl-6- [2- (2,3,6) , 7-Tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCM2 N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, N′-tetrakis (4-Methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2- {2-isopropyl-6- [2- (1,1,7,7- Tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTI), 2- { 2-tert-butyl-6- [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl]- 4H-Pyra -4-ylidene} propanedinitrile (abbreviation: DCJTB), 2- (2,6-bis {2- [4- (dimethylamino) phenyl] ethenyl} -4H-pyran-4-ylidene) propanedinitrile (abbreviation) : BisDCM), 2- {2,6-bis [2- (8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolidine -9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM).

As the organic compound that disperses the light-emitting substance, when the light-emitting substance is a fluorescent compound, a substance having a singlet excitation energy (energy difference between the ground state and the singlet excited state) larger than that of the fluorescent compound is used. preferable. In the case where the light-emitting substance is a phosphorescent compound, a substance having a triplet excitation energy (energy difference between a ground state and a triplet excited state) larger than that of the phosphorescent compound is preferably used.

Examples of the organic compound in which the light-emitting substance is dispersed include tris (8-quinolinolato) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq ₃ ), and bis. (10-hydroxybenzo [h] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis ( 8-quinolinolato) zinc (II) (abbreviation: Znq), bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: Zn (BOX) ₂ ), bis [2- (2-benzothiazolyl) ) phenolato] zinc (II) (abbreviation: Zn _{(BTZ) 2)} metal complexes, such as, 2- (4-biphenylyl) -5- (4 tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazole-2- Yl] benzene (abbreviation: OXD-7), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 2,2 ', 2''-(1,3,5-benzenetriyl) tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 9 Heterocyclic compounds such as-[4- (5-phenyl-1,3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (abbreviation: CO11), 4,4'-bis [N- ( 1- Butyl) -N-phenylamino] biphenyl (abbreviation: NPB or α-NPD) and N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4, Aromatic amines such as 4′-diamine (abbreviation: TPD) and 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB) Compounds. In addition, condensed polycyclic aromatic compounds such as anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo [g, p] chrysene derivatives can be given. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth) N, N-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: CzA1PA), 4- (10-phenyl-9-anthryl) triphenyl Amine (abbreviation: DPhPA), YGAPA, PCAPA, N, 9-diphenyl-N- {4- [4- (10-phenyl-9-anthryl) phenyl] phenyl} -9H-carbazol-3-amine (abbreviation: PCAPBA) ) 2PCAPA, 6,12-dimethoxy-5,11-diphenylchrysene, N, N, ', N', N ″, N ″, N ′ ″, N ′ ″-octaphenyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA), 3,6-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: DPCzPA), 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10- Di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,9′-bianthryl (abbreviation: BANT), 9,9 ′-(stilbene-3,3′-diyl) diphenanthrene (abbreviation: DPNS) 9,9 ′-(stilbene-4,4′-diyl) diphenanthrene (abbreviation: DPNS2), 3,3 ′, 3 ″-(benzene-1,3,5-triyl) tripylene (abbreviation: TPB3) And so on.

Note that as the film formation material included in the material layer 105, two or more kinds of organic compounds in which a light-emitting substance is dispersed may be used, or two or more kinds of light-emitting substances dispersed in an organic compound may be used. Further, an organic compound in which two or more kinds of luminescent substances are dispersed and two or more kinds of luminescent substances may be used.

In this embodiment, 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA) and 9,10-diphenyl-2- [N] are used as film formation materials included in the material layer 105. -Phenyl-N- (9-phenyl-9H-carbazol-3-yl) amino] anthracene (abbreviation: 2PCAPA) is used.

The material layer 105 may contain a polymer compound in addition to the film formation material. As the polymer compound included in the material layer 105, a cycloolefin polymer is preferable. Since the cycloolefin polymer is easily dissolved in a solvent, after forming a film on the film formation substrate, the cycloolefin polymer containing the film formation material remaining on the film formation substrate is redissolved in the solvent. It can be reused. Therefore, the consumption and cost of the material can be suppressed. Further, as the polymer compound, olefin, vinyl, acrylic, polyimide (PI), or the like may be used, or a polymer material EL material may be used. Examples of the polymer material EL material include poly (N-vinylcarbazole) (PVK) and poly (p-phenylene vinylene) (PPV). In addition, a cross-linked polymer such as an epoxy resin, an acrylic resin, or siloxane may be used.

In the case where a plurality of film formation materials (for example, a first film formation material and a second film formation material) are used for the material layer 105, the glass transition temperature of the high molecular compound used for the material layer 105 is represented by the following formula ( A polymer compound satisfying 1) is preferred. More preferably, a polymer compound having a glass transition temperature satisfying the following mathematical formula (2) is used. Note that in the following formulas (1) and (2), the sublimation temperatures of the first film-forming material and the second film-forming material are measured at the same degree of vacuum (for example, a degree of vacuum of 10 ⁻³ Pa).

(In the formula (1) (2), S represents the glass transition temperature (℃) of the polymer compound, T _a, of the first film forming material or the second sublimation temperature of the film forming material (℃) High temperature (℃))

If the glass transition temperature of the polymer compound is in the range satisfying the above formula (1), preferably the above formula (2), the temperature reaches the lower one of the sublimation temperatures of the first film forming material or the second film forming material. However, the film-forming material that has reached the sublimation temperature is hardly transferred from the material layer. This is because the high molecular compound suppresses the movement of the first film formation material and the second film formation material in the material layer. When the temperature of the sublimation temperature of the first film forming material or the second film forming material exceeds a high temperature, the first film forming material and the second film forming material can easily move in the material layer. And transferred onto the deposition substrate. Accordingly, a time difference is hardly generated between the transfer of the first film formation material and the transfer of the second film formation material, and a light-emitting layer with a small concentration gradient can be formed over the deposition target substrate.

However, if the glass transition temperature of the polymer compound is lower than the range of the above mathematical formula (1), the first film-forming material and the second film-forming material are difficult to suppress movement in the material layer. When the temperature reaches the lower sublimation temperature of the film forming material or the second film forming material, the film forming material having the lower sublimation temperature is transferred first, and then the film forming material having the higher sublimation temperature is transferred. Further, if the glass transition temperature of the polymer compound is higher than the range of the mathematical formula (1), the first film-forming material and the second film-forming material after the first sublimation temperature exceeds a high temperature, The film-forming material and the second film-forming material are prevented from moving in the material layer, and transfer is not easily performed.

Therefore, as the polymer compound, it is preferable to use a polymer compound having a glass transition temperature that satisfies the above formula (1), preferably the above formula (2). Note that in this embodiment mode, transfer means that the first film formation material or the second film formation material included in the material layer is transferred onto the deposition target substrate.

Note that a material having a glass transition temperature of 200 ° C. was used as the polymer compound, and a material having a sublimation temperature of 210 ° C. and a material having a sublimation temperature of 260 ° C. were used as the first film formation material and the second film formation material. In some cases, good transfer was achieved. On the other hand, a material having a glass transition temperature of 200 ° C. is used as the polymer compound, and a material having a sublimation temperature of 210 ° C. and a material having a sublimation temperature of 302 ° C. are used as the first film forming material and the second film forming material. If it was, good transfer was not realized. This indicates that a suitable EL layer can be realized under the conditions meeting the above formulas (1) and (2).

Since the viscosity of the polymer compound can be easily adjusted, the viscosity of the polymer compound solution can be freely adjusted according to the application. For example, in the case where the material layer 105 is formed by a droplet discharge method, by increasing the viscosity of the polymer compound solution, the polymer compound does not spread on the deposition surface, and a fine pattern can be formed. it can.

Adjustment of the viscosity of the polymer compound solution can be achieved by adjusting the molecular weight of the polymer compound or changing the ratio of the polymer compound and the solvent. In general, as the ratio of the polymer compound increases, the viscosity of the solution increases.

Note that the thickness of a film formation material layer formed over the base layer 109 in a later step depends on the material layer 105 formed over the first substrate 101. Therefore, by controlling the thickness of the material layer 105, the thickness of the deposition material layer formed over the base layer 109 can be easily controlled. Note that the material layer 105 is not necessarily a uniform layer as long as the thickness and uniformity of the deposition material layer can be maintained. For example, it may be formed in a fine island shape, or may be formed in a layered structure.

Further, although the case where the absorption layer 103 and the material layer 105 are formed over the entire surface of the first substrate 101 has been described in this embodiment, the absorption layer 103 and the material layer 105 may be selectively formed.

Note that in this embodiment, a support substrate having a material layer including a film formation material and having an area approximately the same as a deposition target substrate is used; however, this embodiment is not limited thereto. Instead, the supporting substrate need not have the same area as the deposition target substrate.

Note that the film formation substrate only needs to have the material layer 105 formed on the outermost surface of the surface on which the absorption layer 103 is formed, and between the first substrate 101 and the absorption layer 103 or between the absorption layer 103 and the material layer. Another layer may be provided between the layers 105.

Next, a method for manufacturing the deposition target substrate illustrated in FIG.

The second substrate 107 is a deposition target substrate on which a desired layer is formed by heat treatment. The second substrate 107 is not limited to a specific one as long as it has necessary heat resistance and has an insulating surface. For example, a glass substrate, a quartz substrate, a stainless steel substrate on which an insulating film is formed, and the like can be given. Alternatively, a plastic substrate having heat resistance enough to withstand heat treatment may be used.

Note that although not illustrated in FIG. 1, here, in order to describe the case where a light-emitting element is formed using the film formation method of one embodiment of the present invention, one of the light-emitting elements is formed over the second substrate 107. It has the 1st electrode layer used as an electrode. The end of the first electrode layer is preferably covered with an insulator. In this embodiment mode, the first electrode layer indicates an electrode which serves as an anode or a cathode of the light emitting element.

A base layer 109 is formed on the first electrode layer. As the main component of the base layer 109, the same substance as the main component of the deposition material included in the material layer 105 of the deposition substrate is used. In particular, the base layer 109 is preferably formed using a film formation material included in the material layer 105.

In this embodiment mode, a hole transport layer is formed as the base layer 109. The hole transport layer is a layer containing a substance having a high hole transport property, and examples of the substance having a high hole transport property include 4,4′-bis [N- (1-naphthyl) -N-phenylamino. ] Biphenyl (abbreviation: NPB or α-NPD) and N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl)- N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB), etc. An aromatic amine compound or the like can be used. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Note that the layer containing a substance having a high hole-transport property is not limited to a single layer, and two or more layers containing the above substances may be stacked.

In this embodiment, 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA) is used for the base layer 109 as a material having a high hole-transport property.

Although the case where the base layer 109 is a hole transport layer is described in this embodiment mode, the present invention is not limited to this. In this embodiment mode, the deposition substrate may have the base layer 109 on the outermost surface of the deposition surface, and other layers may be interposed between the first electrode layer and the base layer 109. It may be formed.

Next, as illustrated in FIG. 1B, the base layer 109 of the second substrate 107 is formed on the first substrate 101 at a position facing the surface on which the absorption layer 103 and the material layer 105 are formed. Arrange the surface.

The surface of the material layer 105 and the surface of the base layer 109 are arranged with an interval of a distance d. Here, the distance d is greater than 0 mm and 2 mm or less, preferably greater than 0 mm and 0.05 mm or less, more preferably greater than 0 mm and 0.03 mm or less. By reducing the distance d to approximately the above range, the utilization efficiency of the film forming material can be improved. In this embodiment mode, the distance between the deposition substrate and the deposition target substrate is narrowed (in order to reduce the distance d) in order to improve the material utilization efficiency. The form is not limited to this.

Further, although the case where the number of deposition target substrates is one is described in this embodiment mode, a plurality of deposition target substrates may be arranged side by side so as to face the deposition target substrate. In this case, the areas of the plurality of deposition target substrates and the deposition substrate are set to be approximately the same. By providing a plurality of deposition substrates with respect to the deposition substrate, a plurality of deposition substrates can be processed at the same time.

The surface of the material layer 105 and the surface of the base layer 109 are preferably arranged so as to be parallel to each other.

The first substrate 101 and the second substrate 107 only need to face each other, and the angle of these substrates with respect to the horizontal plane is not particularly limited. That is, a film formation apparatus used in one embodiment of the present invention may be a face-down method, a face-up method, or a vertical substrate method.

Then, as shown in FIG. 1C, by performing heat treatment from the back surface of the first substrate 101, that is, from the other surface side of the first substrate 101 in which the material layer 105 is formed on one surface, The absorption layer 103 absorbs energy to generate heat, and the deposition material in the heated material layer 105 is deposited on the deposition target substrate. The heat treatment is performed so that the entire surface of the first substrate 101 is heated. By the heat treatment, a deposition material layer 111 that is a light-emitting layer of the light-emitting element is formed over the base layer 109.

Here, since the distance between the material layer 105 and the base layer 109 is narrow, the temperature of the base layer 109 rapidly increases during the heat treatment, and in the film formation material layer 111 formed in contact with the base layer 109, The film forming material and the material of the underlayer may be mixed. However, in this embodiment mode, CzPA is used as the main component of the deposition material included in the material layer 105 and the material of the base layer 109. In this manner, by using the same material as the main component of the base layer 109 as the main component of the film formation material included in the material layer 105 (preferably, the base layer 109 is formed using a substance used for the film formation material). In addition, it is possible to prevent a material other than the film formation material from being mixed into the film formation material layer 111.

In this embodiment mode, the temperature of the heat treatment is preferably set higher than the sublimation temperature of the film formation material and in a range not exceeding 50 ° C. than the sublimation temperature of the film formation material. Further, depending on the distance between the first substrate and the second substrate, or the material and thickness of the second substrate which is the film formation substrate, in order to reduce the influence of the radiant heat of the heat source, the above temperature range may be satisfied. It may be set lower. Here, the temperature of the heat treatment is measured on the surface of the first substrate.

In the case of using a plurality of film formation materials, it is preferable to perform heat treatment so that the sublimation temperature of the plurality of film formation materials is equal to or higher than the highest sublimation temperature. In this case, it is preferable to set the temperature higher than the sublimation temperature of the film forming material having the highest sublimation temperature and up to 50 ° C., but the decomposition temperature of the substance having the lower sublimation temperature, In consideration of the distance and the material and thickness of the film formation substrate, the temperature may be set to a lower temperature within the above temperature range (however, the sublimation temperature of the substance having the highest sublimation temperature).

The heat treatment is preferably performed by a method of irradiating the first substrate 101 with light using a lamp or a laser oscillation device. The lamp and the laser oscillation device may be installed so that the back surface of the first substrate 101 can be irradiated with light.

As the lamp, a flash lamp (xenon flash lamp, krypton flash lamp, etc.), a xenon lamp, a discharge lamp typified by a metal halide lamp, a heating lamp typified by a halogen lamp, or a tungsten lamp can be used. Since the flash lamp can repeatedly irradiate a large area with a very high intensity light in a short time (0.1 milliseconds to 10 milliseconds), it is efficient regardless of the area of the first substrate 101. It can be heated uniformly. In addition, heating of the first substrate 101 can be controlled by changing a time interval of light emission. Further, since the flash lamp has low power consumption during light emission standby and a long life, the running cost can be kept low.

A laser oscillation device may be used as a light source other than the lamp. As the laser light, gas laser such as Ar laser, Kr laser, excimer laser, single crystal YAG, YVO ₄ , forsterite (Mg ₂ SiO ₄ ), YAlO ₃ , GdVO ₄ , or polycrystalline (ceramic) YAG, A laser using a medium in which one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta are added as dopants to Y ₂ O ₃ , YVO ₄ , YAlO ₃ , and GdVO ₄ , A glass laser, a ruby laser, an alexandrite laser, a Ti: sapphire laser, a copper vapor laser, or a gold vapor laser that is oscillated from one or a plurality of types can be used. In addition, when a solid-state laser whose laser medium is solid is used, there are advantages that a maintenance-free state can be maintained for a long time and output is relatively stable.

In addition, film formation by light irradiation is preferably performed in a reduced pressure atmosphere. Therefore, it is preferable that the film forming chamber has an atmosphere of 5 × 10 ⁻³ Pa or less, preferably 10 ⁻⁴ Pa or less. Note that although heat treatment is performed using a light source in this embodiment mode, heat treatment may be performed using a heat source such as a heater.

As described above, since the film formation method described in this embodiment uses the same material for the main component of the film formation material layer and the main component of the base layer, a material other than the film formation material is used for the film formation material layer. Can be prevented from being mixed. Therefore, in a light-emitting element manufactured using the film formation method of one embodiment of the present invention, light emission efficiency, lifetime, and the like of a light-emitting element which are generated when an EL material forming another layer is mixed into one layer of the EL layer. A decrease in performance can be suppressed.

Note that this embodiment can be freely combined with any of the other embodiments.

(Embodiment 2)
In this embodiment, a film formation method of one embodiment of the present invention will be described. Note that in this embodiment, the case where an EL layer of a light-emitting element is formed using the film formation method of one embodiment of the present invention will be described with reference to FIGS. In this embodiment, the EL layer of the light-emitting element includes a hole-transport layer and a light-emitting layer, and the case where the light-emitting layer is formed over the hole-transport layer using the film formation method of one embodiment of the present invention is described. To do. Note that the film formation method described in this embodiment is performed using the same material and manufacturing method as those in the above embodiment, unless otherwise specified.

FIG. 2 shows an example in which a reflective layer, a heat insulating layer, and a protective layer are formed on the first substrate. In FIG. 2A, a reflective layer 302 is selectively formed on one surface of a first substrate 301 which is a support substrate. Note that the reflective layer 302 has an opening 308. In addition, a heat insulating layer 304 is formed on the reflective layer 302. Note that the heat insulating layer 304 has an opening 308 at a position overlapping with the opening of the reflective layer 302. In addition, an absorption layer 303 covering the opening is formed over the first substrate 301 over which the reflective layer 302 and the heat insulating layer 304 are formed. A protective layer 306 is formed over the absorption layer 303. In addition, a material layer 305 containing a film formation material is formed over the protective layer 306.

Note that in this specification, “overlap” means not only a case where elements (for example, a reflective layer and an absorption layer) constituting a film formation substrate are in direct contact with each other but also an overlapping layer. Including the case of overlapping.

A method for manufacturing the deposition substrate illustrated in FIG. 2A will be described below.

First, the reflective layer 302 is selectively formed on one surface of the first substrate 301. The reflective layer 302 is a layer that reflects light applied to the first substrate 301 and blocks the material layer 305 formed in a region overlapping with the reflective layer 302 so as not to apply heat. Therefore, the reflective layer 302 is preferably formed using a material having a high reflectivity with respect to light to be irradiated. Specifically, the reflective layer 302 is preferably formed of a material having a high reflectivity of 85% or more, more preferably 90% or more, with respect to the irradiated light. .

As a material that can be used for the reflective layer 302, for example, aluminum, silver, gold, platinum, copper, an alloy containing aluminum (eg, an aluminum-titanium alloy, an aluminum-neodymium alloy, an aluminum-titanium alloy), or silver can be used. An alloy (silver-neodymium alloy) or the like can be used.

Note that the reflective layer 302 can be formed by various methods. For example, it can be formed by sputtering, electron beam vapor deposition, vacuum vapor deposition, or the like. Moreover, although the film thickness of the reflective layer 302 changes with materials, it is preferable to set it as 100 nm or more. By setting the film thickness to 100 nm or more, the irradiated light can be prevented from passing through the reflective layer 302.

Note that the type of material suitable for the reflective layer 302 varies depending on the wavelength of light with which the first substrate 301 is irradiated. The reflective layer is not limited to a single layer, and may be composed of a plurality of layers. Alternatively, the absorption layer 303 may be formed directly over the first substrate 301 without providing a reflective layer.

Note that the greater the difference in reflectance between the reflective layer 302 and the absorbing layer 303, the better. Specifically, the difference in reflectance with respect to the wavelength of light to be irradiated is preferably 25% or more, more preferably 30% or more.

Various methods can be used to form the opening in the reflective layer 302, but dry etching is preferably used. By using dry etching, the sidewall of the opening becomes sharp and a fine pattern can be formed.

Next, a heat insulating layer 304 is selectively formed over the reflective layer 302. The heat insulating layer 304 is a layer for suppressing the material layer 305 located in the region overlapping with the reflective layer 302 from being heated and sublimated. As the heat insulating layer 304, for example, titanium oxide, silicon oxide, silicon oxynitride, zirconium oxide, titanium carbide, or the like can be preferably used. Note that the heat insulating layer 304 is formed using a material having lower thermal conductivity than the material used for the reflective layer 302 and the absorbing layer 303. Note that in this specification, an oxynitride is a substance that has a higher oxygen content than nitrogen, and a nitrided oxide is a substance that has a higher nitrogen content than oxygen. It is.

The heat insulating layer 304 can be formed using various methods. For example, it can be formed by sputtering, electron beam evaporation, vacuum evaporation, CVD, or the like. Moreover, although the film thickness of a heat insulation layer changes with materials, it is 10 nm or more and 2 micrometers or less, Preferably it can be 100 nm or more and 600 nm or less. By setting the thickness of the heat insulating layer 304 to 10 nm or more and 2 μm or less, even when the reflective layer 302 is heated, there is an effect of blocking heat conduction to the material layer positioned on the reflective layer 302.

The heat insulating layer 304 has an opening formed in a region overlapping with the opening of the reflective layer 302. Various methods can be used for forming the pattern of the heat insulating layer 304, but dry etching is preferably used. By using dry etching, the patterned heat insulating layer 304 has a sharp side wall, and a fine pattern can be formed.

Note that when pattern formation of the heat insulating layer 304 and the reflective layer 302 is performed by a single etching process, the sidewalls of the openings provided in the heat insulating layer 304 and the reflective layer 302 can be aligned, and a finer pattern can be formed. This is preferable.

In this embodiment mode, the heat insulating layer 304 is formed only at a position overlapping the reflective layer 302, but the heat insulating layer 304 may be formed to cover the reflective layer 302 and the opening of the reflective layer 302. In this case, the heat insulating layer 304 needs to have a property of transmitting visible light.

Next, the absorption layer 303 is formed over the heat insulating layer 304. The absorption layer 303 can be formed using a material similar to that of the absorption layer 103 described in Embodiment 1. Note that the absorption layer 303 may be selectively formed. For example, after the absorption layer 303 is formed over the entire surface of the first substrate 301, the absorption layer 303 is patterned, and the pattern is formed in an island shape so as to cover the openings of the reflective layer 302 and the heat insulating layer 304. In this case, compared to the case where the absorption layer is formed on the entire surface, heat can be prevented from being conducted in the surface direction in the absorption layer, so that a finer EL layer pattern can be formed and a high-performance light emitting device can be realized. can do.

Next, the protective layer 306 is formed over the absorption layer 303. The protective layer 306 is formed in order to prevent a substance used for the absorption layer 303 from being sublimated and mixed as an impurity in an EL layer formed over the deposition target substrate. The protective layer 306 prevents the absorption layer 303 from being oxidized, altered, or deformed by heat. By forming the protective layer 306, deterioration of the absorption layer 303 can be prevented, so that the deposition substrate can be used more frequently. Therefore, the consumption and cost of the material can be suppressed. The protective layer 306 includes, for example, silicon nitride, silicon nitride oxide, titanium oxide, silicon oxide, silicon oxynitride, zirconium oxide, titanium nitride, titanium carbide, or indium tin oxide (ITO). Has been. The thickness of the protective layer 306 is preferably such that the absorbing layer 303 can be well protected, and can be, for example, about 100 nm. Note that the protective layer 306 is not necessarily provided. Further, the protective layer 306 may be selectively formed in a portion overlapping with the absorption layer 303.

Next, the material layer 305 is formed over the protective layer 306. The material layer 305 includes at least a deposition material. The structure described in Embodiment 1 can be applied to the deposition material included in the material layer 305. Further, the material layer 305 may be selectively formed. In addition, the substance that is a main component of the film formation material included in the material layer 305 is the same substance as the main component of the base layer 311 over the deposition target substrate.

In this embodiment, 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA) and 9,10-diphenyl-2- [N] are used as film formation materials included in the material layer 305. -Phenyl-N- (9-phenyl-9H-carbazol-3-yl) amino] anthracene (abbreviation: 2PCAPA) is used.

Next, a deposition method using the deposition substrate illustrated in FIG. 2A will be described with reference to FIGS. First, as shown in FIG. 2B, the surface of the second substrate 307 on which the base layer 311 is formed is arranged on the first substrate 301 at a position facing the surface on which the material layer 305 and the like are formed. To do.

Note that here, in order to describe the case where the EL layer of the light-emitting element is formed using the film formation method of one embodiment of the present invention, the first substrate which is one electrode of the light-emitting element is formed over the second substrate 307. An electrode layer 309 is provided. An end portion of the first electrode layer 309 is preferably covered with an insulator 312. In this embodiment mode, the first electrode layer indicates an electrode which serves as an anode or a cathode of the light emitting element.

A base layer 311 is formed over the first electrode layer 309. As the main component of the base layer 311, the same substance as the main component of the deposition material included in the material layer 305 over the deposition substrate is used. In particular, the base layer 311 is preferably formed using a film formation material included in the material layer 305.

In this embodiment, 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA) is used for the base layer 311 in order to form a hole-transport layer.

Although the case where the base layer 311 is a hole transport layer is described in this embodiment mode, the present invention is not limited to this. In this embodiment mode, the deposition substrate may have the base layer 311 on the outermost surface of the deposition surface, and other layers may be provided between the first electrode layer 309 and the base layer 311. May be formed.

The surface of the material layer 305 and the surface of the base layer 311 are arranged with an interval of a distance d. Here, the distance d is greater than 0 mm and 2 mm or less, preferably greater than 0 mm and 0.05 mm or less, more preferably greater than 0 mm and 0.03 mm or less.

Then, as shown in FIG. 2C, the absorption layer is formed by heat treatment from the back surface of the first substrate 301, that is, the other surface side of the first substrate 301 in which the material layer 305 is formed on one surface. The film formation material in the heated material layer 305 is formed on the second substrate 307 by absorbing energy in 303 and generating heat. Thus, a film formation material layer 313 that is a light emitting layer of the light emitting element is selectively formed over the second substrate 307.

Here, since the distance between the surface of the material layer 305 and the base layer 311 is narrow, the temperature of the base layer 311 rapidly increases during the heat treatment, and the film formation material layer 313 formed over the base layer 311 is used. The film forming material and the material of the underlayer may be mixed. However, in this embodiment mode, CzPA is used as the main component of the deposition material included in the material layer 305 and the material of the base layer 311. In this manner, by using the same material as the main component of the base layer 311 as the main component of the film formation material included in the material layer 305 (preferably, the base layer 311 is formed using a substance used for the film formation material). In addition, it is possible to suppress a material other than the film formation material from being mixed into the film formation material layer 313.

In this embodiment, for example, when a lamp is used as a light source, the light 310 irradiated from the back surface of the first substrate 301 is reflected in the region where the reflective layer 302 is formed and is provided in the reflective layer 302. The light passes through the opening 308 and is absorbed by the absorption layer 303 in a region overlapping with the opening. When the absorbed light is converted into thermal energy, the material layer 305 in contact with the absorption layer 303 in the region is heated, and a film formation material is formed over the deposition target substrate.

Note that when the first substrate 301 is irradiated with the light 310, the heat generated in the absorption layer 303 is conducted in the surface direction and the reflective layer 302 in contact with the absorption layer may be heated. Even if the reflective layer 302 is formed using a material having a reflectance of 85% or more, some heat is absorbed depending on the amount of heat of light to be irradiated. However, in the deposition substrate in this embodiment, since the heat insulating layer 304 formed using a material having low thermal conductivity is provided between the reflective layer 302 and the material layer 305, the reflective layer 302 is heated. Even in such a case, heat conduction to the material layer 305 can be blocked in the heat insulating layer 304. Thus, a film formation material included in the material layer 305 in a region overlapping with the opening 308 is selectively formed over the deposition target substrate, and a light-emitting layer having a desired pattern is formed as the film formation material layer 313. can do.

In this embodiment mode, light is irradiated as compared with the case where the entire surface of the material layer is heated in order to selectively heat a region in contact with the absorption layer in the material layer formed over the first substrate. The time can be relatively short. For example, in the case where a halogen lamp is used as a light source, by holding 500 to 800 ° C. for about 7 to 15 seconds, a region of the material layer 305 that overlaps with the opening 308 is heated to form a film formation material. A film can be formed on the substrate.

Note that although the case where the second substrate which is a deposition target substrate is located below the first substrate which is a supporting substrate is illustrated in this embodiment mode, this embodiment mode is not limited thereto. The direction in which the substrate is installed can be set as appropriate.

As described above, the reflective layer and the heat insulating layer are selectively formed on the first substrate, and the absorption layer, the protective layer, and the material layer including the film forming material are formed on the first substrate and the heat insulating layer. When the film is formed, the material layer containing the film formation material is selectively heated, and the pattern formation of the film formation material layer formed on the deposition target substrate can be performed.

In addition, since the film formation method described in this embodiment uses the same material for the main component of the film formation material layer and the main component of the base layer, materials other than the film formation material are mixed into the film formation material layer. Can be prevented. Therefore, it is possible to suppress a decrease in performance such as light emission efficiency and lifetime of the light emitting element, which is caused by mixing an EL material forming another layer into a layer having an EL layer.

Note that this embodiment can be freely combined with any of the other embodiments.

(Embodiment 3)
In this embodiment, a light-emitting device capable of full-color display by forming an EL layer of a light-emitting element using a plurality of deposition substrates in the film formation method of one embodiment of the present invention described in Embodiment 2 A manufacturing method of will be described.

In Embodiment Mode 1 and Embodiment Mode 2, a case where a light-emitting layer made of the same material is formed on a plurality of base layers formed on a deposition target substrate in one film formation process is shown. In this embodiment, the case where any one of three types of light emitting layers having different light emission is formed over a plurality of base layers formed over a deposition target substrate will be described.

First, three deposition substrates shown in FIG. 2A in Embodiment Mode 2 are prepared. However, each support substrate is formed with a material layer including a film forming material for forming light emitting layers having different light emission. Specifically, a deposition substrate (R) having a material layer (R) containing a deposition material for forming a light emitting layer (light emitting layer (R)) that emits red light, and a light emitting layer that emits green light. In order to form a film-forming substrate (G) having a material layer (G) containing a film-forming material for forming (light-emitting layer (G)) and a light-emitting layer (light-emitting layer (B)) that emits blue light. A film formation substrate (B) having a material layer (B) containing the film formation material is prepared.

In addition, one deposition target substrate including the plurality of first electrodes and the base layer illustrated in FIG. 2B in Embodiment Mode 2 is prepared. An underlayer (R) in which the same material as the main component of the film forming material included in the material layer (R), the material layer (G), or the material layer (B) is used as a main component of the deposition target substrate. The underlayer (G) and the underlayer (B) are formed. Another layer such as a hole injection layer may be formed between the first electrode of the deposition target substrate and the base layer. Note that as illustrated in FIG. 2B, the end portions of the plurality of first electrodes over the deposition target substrate are covered with the insulator 414, and thus the light-emitting region is formed using the first electrode. It corresponds to a part of the region that is exposed without overlapping with the insulator.

First, as a first film formation step, the film formation substrate and the film formation substrate (R) are overlapped and aligned as in FIG. Note that an alignment marker is preferably provided on the deposition target substrate. In addition, it is preferable to provide an alignment marker on the deposition substrate (R). Note that since the absorption substrate, the material layer, and the like are provided on the deposition substrate (R), the absorption layer, the material layer, and the like around the alignment marker are preferably removed in advance.

Then, light is irradiated from the back surface (the surface on which the reflective layer 302, the heat insulating layer 304, the absorption layer 303, the protective layer 306, and the material layer 305 shown in FIG. 2 are not formed) of the film formation substrate (R). The absorption layer absorbs the irradiated light and applies heat to the material layer (R), so that the film formation material included in the material layer (R) is heated and the base layer (R) on the film formation substrate is heated. A light emitting layer (R) is formed thereon. After the first film formation, the film formation substrate (R) is moved to a place away from the film formation substrate.

Next, as a second film formation step, the film formation substrate and the film formation substrate (G) are overlapped and aligned. In the film formation substrate (G), an opening portion of the reflective layer is formed so as to be shifted by one pixel from the film formation substrate (R) used in the first film formation.

Then, light is irradiated from the back surface (the surface on which the reflective layer 302, the heat insulating layer 304, the absorption layer 303, the protective layer 306, and the material layer 305 shown in FIG. 2 are not formed) of the film formation substrate (G). The absorption layer absorbs the irradiated light and applies heat to the material layer (G), so that the film formation material included in the material layer (G) is heated and is part of the deposition target substrate. The light emitting layer (G) is formed on the base layer (G) adjacent to the base layer (R) on which the light emitting layer (R) is formed in the first film formation. After the second deposition, the deposition substrate (G) is moved to a location away from the deposition target substrate.

Next, as a third film formation step, the film formation substrate and the film formation substrate (B) are overlapped and aligned. In the film formation substrate (B), an opening portion of the reflective layer is formed by being shifted by two pixels from the film formation substrate (B) used in the first film formation.

Then, light is irradiated from the rear surface (the surface on which the reflective layer 302, the heat insulating layer 304, the absorption layer 303, the protective layer 306, and the material layer 305 shown in FIG. 2 are not formed) of the deposition substrate (B). The state immediately before the third film formation corresponds to the top view of FIG. In FIG. 3A, the reflective layer 401 has an opening 402. Therefore, the light transmitted through the opening 402 of the reflective layer 401 of the deposition substrate (B) is transmitted through the heat insulating layer and absorbed by the absorption layer. In addition, a base layer (B) is formed in a region overlapping with the opening 402 of the deposition substrate (B) of the deposition target substrate. Note that the light-emitting layer (R) 411 already formed by the first film formation and the second film formation are formed over the deposition target substrate below the region indicated by the dotted line in FIG. The light emitting layer (G) 412 is located.

Then, the light emitting layer (B) 413 is formed by the third deposition. The absorption layer absorbs the irradiated light and applies heat to the material layer (B), so that the deposition material included in the material layer (B) is heated and is part of the deposition target substrate. The light emitting layer (B) 413 is formed on the base layer (B) adjacent to the base layer (G) on which the light emitting layer (G) 412 is formed in the second film formation. After the third deposition, the deposition substrate (B) is moved to a location away from the deposition target substrate.

In this manner, the light-emitting layer (R) 411, the light-emitting layer (G) 412, and the light-emitting layer (B) 413 can be formed over the same deposition target substrate at regular intervals (see FIG. 3B). A light emitting element can be formed by forming a second electrode over these films. Further, another layer such as an electron transport layer may be formed between the light emitting layer and the second electrode.

Through the above process, a light-emitting element capable of full color display can be formed by forming light-emitting elements that emit different light on the same substrate.

Although FIG. 3 shows an example in which the shape of the opening 402 of the reflective layer formed on the deposition substrate is rectangular, the shape is not particularly limited, and may be a stripe-shaped opening. In the case of a stripe-shaped opening, a film is also formed between light emitting regions having the same light emission color. However, since the film is formed on the insulator 414, a portion overlapping with the insulator 414 is not a light emitting region. .

Further, the pixel arrangement is not particularly limited, and one pixel shape may be a polygon, for example, a hexagon. Note that in order to form a polygonal pixel, a film formation substrate having a reflective layer having a polygonal opening may be used.

Note that in this embodiment mode, three film formation substrates are used to form three types of light emitting layers having different light emission, but a material layer (R) and a material layer ( G) and the material layer (B) may be selectively formed. In this case, the deposition substrate and the deposition substrate need only be aligned once, which is preferable because the utilization efficiency and productivity of the material are increased.

In manufacturing a light-emitting device capable of full-color display described in this embodiment, the thickness of a film formed over a deposition target substrate is controlled by controlling the thickness of a material layer formed over the deposition substrate. Can be controlled. That is, the thickness of the material layer is set in advance so that the film formed on the deposition target substrate has a desired thickness by heating all the deposition materials included in the material layer formed on the deposition substrate. Therefore, it is not necessary to monitor the film thickness when the film is formed on the film formation substrate. Therefore, it is not necessary for the user to adjust the deposition rate using the film thickness monitor, and the film forming process can be fully automated. Therefore, productivity can be improved.

In addition, since the film formation method described in this embodiment uses the same material for the main component of the film formation material layer and the main component of the base layer, materials other than the film formation material are mixed into the film formation material layer. Can be prevented. Therefore, it is possible to suppress a decrease in performance such as light emission efficiency and lifetime of the light emitting element, which is caused by mixing an EL material forming another layer into a layer having an EL layer. Therefore, a highly reliable light-emitting device can be realized by using a light-emitting element manufactured by the film formation method of one embodiment of the present invention.

Note that the structure described in this embodiment can be combined with any of the structures described in Embodiments 1 and 2 as appropriate.

In this example, an example of a light-emitting element having a light-emitting layer formed using the film formation method of one embodiment of the present invention will be described with reference to FIGS. Note that structural formulas of substances used in this example are shown below.

A method for manufacturing the light-emitting element 1 and the comparative light-emitting element 2 manufactured in this example will be described below.

(Light emitting element 1)
First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate 1100 by a sputtering method, so that a first electrode 1101 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm. Here, the first electrode 1101 is an electrode functioning as an anode of the light-emitting element.

Next, as a pretreatment for forming a light-emitting element over the substrate 1100, the surface of the substrate was washed with water, baked at 200 ° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

Thereafter, the substrate is introduced into a vacuum vapor deposition apparatus whose internal pressure is reduced to about 10 ⁻⁴ Pa, vacuum baking is performed at 170 ° C. for 30 minutes in a heating chamber within the vacuum vapor deposition apparatus, and then the substrate 1100 is subjected to about 30 minutes. Allowed to cool.

Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode 1101 is formed is downward, and 10 ⁻⁴ Pa. After reducing the pressure to the extent, 9- [4- (N-carbazolyl) phenyl] -10-phenylanthracene (abbreviation: CzPA) and molybdenum oxide (VI) are formed on the first electrode 1101 by an evaporation method using resistance heating. ) Was co-evaporated to form a hole injection layer 1111. The film thickness was 50 nm, and the weight ratio of CzPA to molybdenum oxide (VI) was adjusted to 4: 2 (= CzPA: molybdenum oxide). Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

Next, CzPA was formed to a thickness of 10 nm over the hole injection layer 1111 to form a hole transport layer 1112.

Further, by using the film formation method of one embodiment of the present invention, CzPA and 9,10-diphenyl-2- [N-phenyl-N- (9-phenyl-9H-carbazole-3-] are formed over the hole-transport layer 1112. The light emitting layer 1113 made of (yl) amino] anthracene (abbreviation: 2PCAPA) was formed. Here, the weight ratio of CzPA and 2PCAPA was adjusted to be 1: 0.01 (= CzPA: 2PCAPA). The thickness of the light emitting layer 1113 was set to 30 nm.

After that, tris (8-quinolinolato) aluminum (III) (abbreviation: Alq) is formed to a thickness of 10 nm on the light-emitting layer 1113, and then bathophenanthroline (abbreviation: BPhen) is formed on the Alq layer. A film was formed to a thickness of 20 nm, and an electron transport layer 1114 made of Alq and BPhen was formed.

Further, lithium fluoride (LiF) was vapor-deposited with a thickness of 1 nm on the electron transport layer 1114 to form an electron injection layer 1115.

Lastly, as the second electrode 1103 functioning as a cathode, aluminum was deposited to a thickness of 200 nm, whereby the light-emitting element 1 of this example was manufactured.

Note that, in the above-described vapor deposition process, the vapor deposition was all performed by a resistance heating method.

Here, a method for manufacturing the light-emitting layer 1113 using the film formation method of one embodiment of the present invention is specifically described.

A glass substrate was used as the support substrate. A titanium film having a thickness of 150 nm was selectively formed as an absorption layer on the supporting substrate. Then, a silicon nitride film having a thickness of 100 nm was formed as a protective layer on the absorption layer.

Further, a material layer was formed on the protective layer by a wet method. The material layer includes a film forming material and a polymer compound. 2PCAPA and CzPA were used as film forming materials. In addition, a cycloolefin polymer having a glass transition temperature of 285 ° C. was used as the polymer compound, and these materials were dissolved in toluene used as a solvent. The ratio of toluene, cycloolefin polymer, CzPA and 2PCAPA was adjusted to be 250: 5: 1: 0.1 (= toluene: cycloolefin polymer: CzPA: 2PCAPA) by weight. The film thickness of the material layer was 150 nm.

After the material layer was formed, heat treatment was performed in a vacuum atmosphere in order to remove toluene remaining in the material layer. Specifically, it was heated at a vacuum degree of 1 Pa and 160 ° C. for 1 hour.

Next, the deposition target substrate was disposed on the support substrate at a position facing the surface on which the absorption layer and the material layer were formed. The deposition target substrate was disposed with the surface side on which the hole transport layer 1112 of the light emitting element 1 was formed on the outermost surface of the substrate 1100 facing the support substrate. At this time, the distance d between the surface of the material layer and the surface of the hole transport layer 1112 was set to 100 μm. In addition, film formation by light irradiation is preferably performed in a reduced pressure atmosphere. Therefore, the degree of vacuum in the film formation chamber was kept at 5 × 10 ⁻³ Pa or less. Then, the material layer is heated by irradiating a halogen lamp from the back surface of the support substrate, that is, the other surface side of the support substrate on which the material layer is formed, for 9 seconds to emit light on the hole transport layer 1112 of the glass substrate 1100. Layer 1113 was formed.

(Comparative light emitting element 2)
Except for the hole-injection layer 1111 and the hole-transport layer 1112, the light-emitting element 1 was manufactured. Specifically, the hole injection layer 1111 is formed by co-evaporation of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB) and molybdenum oxide (VI). Formed. The film thickness was 50 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1 (= NPB: molybdenum oxide). Further, NPB was formed to a thickness of 10 nm, whereby a hole transport layer 1112 was formed.

Table 1 shows element structures of the light-emitting element 1 and the comparative light-emitting element 2 obtained as described above.

After performing the operation | work which seals the light emitting element 1 and the comparative light emitting element 2 with a glass substrate so that a light emitting element may not be exposed to air | atmosphere in a nitrogen atmosphere glove box, it measured about the operating characteristic of these light emitting elements. It was. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

FIG. 5 shows voltage-luminance characteristics of the light-emitting element 1 and the comparative light-emitting element 2. In FIG. 5, the horizontal axis represents applied voltage (V), and the vertical axis represents luminance (cd / m ² ). Further, FIG. 6 shows luminance-current efficiency characteristics. In FIG. 6, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). Further, FIG. 7 shows an emission spectrum when a current of 1 mA is passed. In FIG. 7, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). In addition, Table 2 shows voltage (V), current density (mA / cm ² ), CIE chromaticity coordinates (x, y), and current efficiency (cd / A) when the luminance is around 750 cd / cm ² in each light-emitting element. Show.

As can be seen from the CIE chromaticity coordinates in FIG. 7 and Table 2, it was found that light emission derived from 2PCAPA was obtained from the manufactured light-emitting element 1 and comparative light-emitting element 2. Further, as can be seen from FIG. 5, the light-emitting element 1 has higher luminance at a lower voltage than the comparative light-emitting element 2.

Next, the reliability test of the light-emitting element 1 and the comparative light-emitting element 2 was performed. The result of the reliability test is shown in FIG. In FIG. 8, the vertical axis represents normalized luminance (%) when the initial luminance is 100%, and the horizontal axis represents element driving time (h). In the reliability test, the initial luminance was set to 1000 cd / m ² , and the light-emitting element 1 and the comparative light-emitting element 2 of this example were driven under a condition where the current density was constant. From FIG. 8, the luminance after 1300 hours of the light emitting element 1 maintained 64% of the initial luminance, and the luminance after 430 hours of the comparative light emitting element 2 maintained 50% of the initial luminance. It became clear that the light emitting element 1 showed higher reliability than the comparative light emitting element 2.

In the method for manufacturing the light-emitting layer 1113 in this embodiment, the distance between the material layer and the hole-transport layer 1112 is narrow during the heat treatment, and thus the light-emitting layer 1113 is formed in the light-emitting layer 1113 formed over the hole-transport layer 1112. In some cases, the film forming material and the material of the hole transporting layer 1112 are mixed. In the comparative light-emitting element 2 of this example, NPB is used for the hole transport layer 1112, and CzPA and 2PCAPA are used for the film forming material. Therefore, NPB is mixed in the light emitting layer 1113 during the heat treatment, and the lifetime of the element is reduced. On the other hand, since the light-emitting element 1 uses CzPA as the main component of the hole transporting layer 1112 and the film forming material, it is possible to prevent a material other than the film forming material from being mixed into the light emitting layer 1113, thereby extending the life of the element. Led to.

101 First substrate 103 Absorbing layer 105 Material layer 107 Second substrate 109 Underlayer 111 Film forming material layer 301 First substrate 302 Reflecting layer 303 Absorbing layer 304 Heat insulating layer 305 Material layer 306 Protective layer 307 Second substrate 308 Opening 309 First electrode layer 310 Light 311 Base layer 312 Insulator 313 Film forming material layer 401 Reflective layer 402 Opening 411 Light emitting layer (R)
412 Light emitting layer (G)
413 Light emitting layer (B)
414 Insulator 1100 Substrate 1101 First electrode 1103 Second electrode 1111 Hole injection layer 1112 Hole transport layer 1113 Light emitting layer 1114 Electron transport layer 1115 Electron injection layer

Claims (10)

1st board | substrate which has the absorption layer formed on the one surface of a board | substrate, and the material layer which is formed on the said absorption layer and was formed in the outermost surface of the one surface of the said board | substrate, and formed into a film-forming material One side of
A second substrate having a base layer formed on the outermost surface of the deposition surface of the substrate, the deposition surface of the second substrate is opposed to each other,
By performing heat treatment from the other surface side of the first substrate, the absorption layer absorbs energy to generate heat, and the film formation material contained in the heated material layer is formed on the base layer. A film forming method for forming a film material layer,
A film forming method using the same substance as a main component of the film forming material layer and a main component of the underlayer. 1st board | substrate which has the absorption layer formed on the one surface of a board | substrate, and the material layer which is formed on the said absorption layer and was formed in the outermost surface of the one surface of the said board | substrate, and formed into a film-forming material One side of
A second substrate having a base layer formed on the outermost surface of the deposition surface of the substrate, the deposition surface of the second substrate is opposed to each other,
By performing heat treatment from the other surface side of the first substrate, the absorption layer absorbs energy to generate heat, and the film formation material contained in the heated material layer is formed on the base layer. A film forming method for forming a film material layer,
A film forming method for forming the underlayer with a material used for the film forming material layer. In claim 1 or claim 2,
The film formation method in which the absorption layer is formed in an island shape or a stripe shape. In claim 3,
The film forming method wherein the material layer is formed in an island shape or a stripe shape. In any one of Claims 1 thru | or 4,
A film forming method in which a reflective layer having an opening is formed between the first substrate and the absorbing layer. In claim 5,
The film-forming method which forms the heat insulation layer which has an opening part in the position which overlaps with the opening part of the said reflection layer between the said reflection layer and the said absorption layer. In any one of Claims 1 thru | or 6,
A film forming method in which a protective layer is formed between the absorption layer and the material layer. In any one of Claims 1 thru | or 7,
The material layer is formed on the absorbing layer by vapor deposition, sputtering, spin coating, printing, droplet ejection, spraying, dropping, inkjet, nozzle printing, or dispensing. . In any one of Claims 1 thru | or 8,
The heat treatment is a film formation method using a method in which light is irradiated from the other surface side of the first substrate using a light source, and the absorption layer is heated by absorbing light. In claim 9,
A film forming method using a laser oscillation device, a flash lamp or a halogen lamp as the light source.