JP5258669B2 - Film forming method and transfer substrate - Google Patents

Description

  The invention disclosed in this specification relates to a film formation method and a method for manufacturing a light-emitting device.

  Light-emitting elements using organic compounds having characteristics such as thin and light weight, high-speed response, and direct current low-voltage driving as light emitters are applied to next-generation flat panel displays. In particular, a display device in which light emitting elements are arranged in a matrix is considered to be superior to a conventional liquid crystal display device in that it has a wide viewing angle and excellent visibility.

  The light-emitting mechanism of the light-emitting element is such that when a voltage is applied with an EL layer sandwiched between a pair of electrodes, electrons injected from the cathode and holes injected from the anode are recombined at the emission center of the EL layer. It is said that when excitons are formed and the molecular excitons relax to the ground state, they emit energy and emit light. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.

  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.

  In addition, an organic material is uniformly formed on a substrate called a donor substrate, the donor substrate on which the organic material is formed and the transfer target substrate are superimposed, and the donor is irradiated with a laser beam, and the laser beam is irradiated. A technique for transferring an organic thin film (EL layer of a light emitting element) in a region to a transfer target substrate has been developed (see Patent Documents 1 to 5). As such laser transfer techniques, LIPS (Laser-Induced Pattern-Wise Sublimation), LITI (Laser-Induced Thermal Imaging) (see Patent Document 6), and RIST (Radiation Induced Substimulation Trans) are proposed.

Special table 2007-504621 Japanese Patent Laid-Open No. 2003-223991 JP 2003-308974 A JP 2003-197372 A Japanese Patent Laid-Open No. 10-208881 JP 2006-5328 A

  In order to transfer the organic material to the transfer target substrate using the transfer technique described above, the organic material deposited on the donor substrate may be irradiated with light. However, since an organic material in a region that is not irradiated with light is not used, if there are many regions that are not irradiated with light, the utilization efficiency of the organic material may be lowered.

  In view of this, an object of one embodiment of the present invention is to increase the utilization efficiency of an organic material formed over a donor substrate.

  A light-transmitting substrate having a plurality of recesses on one surface is used as a donor substrate, and a light absorption layer and an organic material are formed on the recesses.

  The concave shape of the concave portion of the donor substrate is such that when the donor substrate and the transfer target substrate are opposed to each other, the surface of the light absorption layer formed on the donor substrate faces the region where the organic material on the transfer target substrate is to be transferred. To design.

  The donor substrate and the transfer target substrate are opposed to each other, and a laser beam or lamp light (hereinafter simply referred to as “light”) is emitted from the other surface of the donor substrate (the surface on which the light absorption layer and the organic material are not formed). Irradiate. When the light is converted into heat in the light absorption layer, the organic material jumps out of the donor substrate.

  At this time, if the temperature of the light absorption layer is uniform, the organic material flies perpendicularly and straight to the surface of the light absorption layer. Therefore, the organic material formed in the concave portion of the donor substrate is transferred onto the transfer target substrate.

  By forming the concave portion of the donor substrate so as to surround a desired region on the transfer target substrate, it is possible to reduce the organic material flying to the region other than the transfer target substrate. Thereby, an organic material can be used efficiently.

  Forming a light absorption layer and a first organic material layer on a first substrate having a plurality of recesses on a first surface, and making a second substrate face the first surface of the first substrate; Light is irradiated from the second surface opposite to the first surface. The present invention relates to a film forming method characterized in that, by irradiating the light, the first organic material layer on the first substrate is skipped, and the second organic material layer is formed on the second substrate.

  The organic material layer is one or more of a light emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

  A light absorption layer and a first organic material layer are formed on a first substrate having a plurality of recesses on a first surface, and the first surface of the second substrate is one of an anode and a cathode. Electrodes and insulators are formed. The first surface of the second substrate is opposed to the first surface of the first substrate, and light is irradiated from the second surface opposite to the first surface. By irradiating the light, the first organic material layer on the first substrate is skipped, and a second organic material layer is formed on the first electrode and the insulator, and the second organic material is formed. The present invention relates to a method for manufacturing a light-emitting device, in which a second electrode which is the other of an anode and a cathode is formed on a layer.

  The organic material layer includes a light emitting layer.

  The first substrate having a plurality of recesses on the first surface is a light-transmitting substrate having a concave cylindrical array surface.

  An organic material is formed in the concave portion of the donor substrate, and the formed organic material is efficiently transferred onto the transfer target substrate by appropriately designing the shape of the concave portion of the donor substrate and the position of the transfer substrate. Can do. Thereby, the utilization efficiency of an organic material can be raised significantly.

Sectional drawing which shows the film-forming method. The figure which shows the structure used for calculation. The figure which shows the structure used for calculation. The figure which shows the relationship between time and temperature in each position. The figure which shows the relationship between time and temperature in each position. The figure which shows temperature distribution. The figure which shows the relationship between the wavelength of light, and relative intensity. 4A and 4B illustrate a method for manufacturing a light-emitting device.

  Hereinafter, embodiments of the invention disclosed in this specification will be described with reference to the drawings. However, the invention disclosed in this specification can be implemented in many different modes, and various changes can be made in form and details without departing from the spirit and scope of the invention disclosed in this specification. It will be readily understood by those skilled in the art. Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in the drawings described below, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

  Note that in the invention disclosed in this specification, a semiconductor device refers to all elements and devices that function by utilizing a semiconductor, and includes an electric device including an electronic circuit, a display device, a light-emitting device, and the like. The category is the electronic equipment.

[Embodiment 1]
Embodiment modes will be described with reference to FIGS. 1A to 1C and FIGS. 8A to 8C.

  First, the base film 102, the light absorption layer 103, and the organic material layer 104 are stacked over the first surface of the donor substrate 101 having a recess on the first surface. As for the donor substrate which has a recessed part, the translucent board | substrate with a concave cylindrical array surface is mentioned, for example. Next, the substrate 111 to be transferred and the first surface of the donor substrate 101 are opposed to each other (see FIG. 1A).

  Note that a protective layer that protects the light absorption layer 103 during light irradiation may be provided between the light absorption layer 103 and the organic material layer 104. The protective layer can be formed using a silicon oxide film or a nitrogen oxide film.

  As the light-transmitting substrate, for example, a glass substrate, a quartz substrate, a plastic substrate containing an inorganic material, or the like can be used. In this embodiment, a glass substrate is used as the light-transmitting substrate.

  The concave cylindrical array surface provided on the first surface of the donor substrate 101 is designed to face the region on the substrate 111 where the organic material layer 104 is to be transferred when facing the substrate 111 to be transferred.

  For example, it is assumed that the pixel formed on the substrate 111 has a size of 100 μm and a pixel pitch of 300 μm. In this case, when the distance between the first surface of the donor substrate 101 and the transfer target substrate 111 is about 10 μm, the radius of curvature of the concave surface of the donor substrate 101 is about 150 μm. When the distance between the first surface of the donor substrate 101 and the substrate 111 to be transferred is about 100 μm, the radius of curvature of the concave surface of the donor substrate 101 is about 210 μm.

  When the distance between the first surface of the donor substrate 101 and the substrate 111 to be transferred is 10 μm or less, the radius of curvature is less than the pixel pitch in the design, so it is necessary to make the plane between the concave and concave shapes of the donor substrate 101 flat. There is. In that case, the reflective layer 108 may be formed on the back surface of the planar portion (see FIG. 1C).

  The reflective layer 108 has a reflectance of 85% or more, more preferably 90% or more, with respect to the irradiated light.

  Therefore, the reflective layer 108 is preferably formed of a material having a high reflectance with respect to the light to be irradiated. For example, aluminum, silver, gold, platinum, copper, an alloy containing aluminum, an alloy containing silver, or the like can be used.

  As the base film 102, any of a silicon oxide film containing nitrogen, a silicon oxide film, a silicon nitride film, and a silicon nitride film containing oxygen may be used. In this embodiment mode, a silicon oxide film containing nitrogen is used as the base film 102. Is used.

  The light absorption layer 103 is preferably formed of a material having a low reflectance with respect to the irradiated light and a high absorption rate. Moreover, it is preferable that it is a material excellent in heat resistance. For example, molybdenum, tantalum nitride, titanium, tungsten, carbon, or the like can be used. In this embodiment, a titanium film is used as the light absorption layer 103.

  A light emitting layer may be used as the organic material layer 104. Furthermore, any of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer can be formed using this embodiment mode. In that case, as the organic material layer 104, a hole is formed. Any of an injection layer, a hole transport layer, an electron transport layer, and an electron injection layer may be used. Alternatively, as the organic material layer 104, a stacked film in which any two or more of a light emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer are stacked may be used.

A vacuum degree of 10 ⁻³ Pa or less is maintained between the donor substrate 101 and the transfer target substrate 111 using a vacuum jig or the like. In this state, the light 105 is irradiated from the second surface opposite to the first surface of the donor substrate 101.

  As the light 105, when a glass substrate or a plastic substrate is used as the donor substrate 101, light from near infrared to near ultraviolet is preferable.

  By placing the donor substrate 101 and the substrate 111 on a stage that scans in the X direction and the Y direction, the entire surface of the donor substrate 101 can be irradiated with the light 105.

  By irradiation with the light 105, the organic material layer 104 over the donor substrate 101 is transferred to the substrate 111 to be transferred, and the organic material layer 107 is formed over the substrate 111 (see FIG. 1B). In FIG. 1B, the transferred organic material layer 107 is an organic material layer 107a, and the organic material layer 107 being transferred is an organic material layer 107b.

  Since the surface of the light absorption layer 103 is concave, the organic material layer 104 jumps out in the direction in which the curved surface faces. Therefore, the organic material layer 104 can be transferred to a desired region of the substrate 111 to be transferred.

  FIGS. 8A to 8C illustrate a method for manufacturing a light-emitting device using the manufacturing steps of FIGS. 1A to 1B. 8A to 8C and FIGS. 1A to 1B are denoted by the same reference numerals.

  A first electrode 121 and an insulator 125 are formed on the first surface of the substrate 111. Next, the donor substrate 101 in which the base film 102, the light absorption layer 103, and the organic material layer 104 are first stacked over the surface is opposed to the first surface of the substrate 111 (see FIG. 8A).

  Next, in the same manner as the manufacturing process illustrated in FIG. 1B, light 105 is irradiated from the second surface of the donor substrate 101, so that the organic material layer 107 is formed over the electrode 121 and the insulator 125 (see FIG. 8B). B)). 8B, similarly to FIG. 1B, the transferred organic material layer 107 is an organic material layer 107a, and the organic material layer 107 being transferred is an organic material layer 107b.

  After the organic material layer 107 is formed, the second electrode 122 is formed over the organic material layer 107 (see FIG. 8C). One of the first electrode 121 and the second electrode 122 may be an anode and the other may be a cathode. Thus, a light emitting element is manufactured.

  Note that when the light-emitting element is manufactured, the organic material layer 104 includes a light-emitting layer, or any one of the light-emitting layer and the hole injection layer, the hole transport layer, the electron transport layer, or the electron injection layer. A laminated film in which one or more are laminated may be used.

  In this embodiment, calculation results of the temperature distribution on the surface of the donor substrate will be described with reference to FIGS. 2, 3, 4, 5, 6 (A) to 6 (B), and 7.

  In this embodiment, a temperature distribution when white light is irradiated from below is obtained using the structure having the synchronous structure shown in FIG. 2 as a calculation model. The structure shown in FIG. 2 includes a base film 102, a light absorption layer 103, and an organic material layer 104 over a donor substrate 101. The donor substrate 101 is set to be a glass substrate, the base film 102 is set to a silicon oxide film having a thickness of 500 nm, the light absorption layer 103 is set to 150 nm, and the organic material layer 104 is set to have a thickness of 50 nm. The radius of curvature R is 210 μm, and the half length L of the pitch of the synchronous structure is 150 μm.

  Further, it is assumed that there is no reflection, interference, or transmission of light in the light absorption layer 103 and no influence of an electromagnetic field. Further, it is assumed that the light intensity at a certain position depends only on the incident angle.

  In calculating the amount of heat generation, the light absorption layer 103 is divided into seven regions (regions 1 to 7) as shown in FIG. 3, and the light intensity at the center point of each region is determined by the light intensity of the region. The amount of heat generated is defined by the ratio of the strength as a representative.

  The amount of heat generation is defined so that the heat generation is 0.2 ms and the surface of the organic material layer 104 is about 300 ° C.

Table 1 shows the energy ratio of each region obtained from the incident angle of light at the center of each region in regions 1 to 7. However, the heat generation amount of the region 1 is 113.4 W / cm ² .

  The light is assumed to be a flash lamp having the relative intensity shown in FIG.

  The temperature distribution of the maximum temperature was around 280 ° C to 340 ° C. At this time, the region below about 300 ° C. is about 26% of the entire region, and the region is a region from region 5 to region 7 as indicated by the dotted line in FIG.

  Although the amount of heat generated in the region 7 is the smallest, the heat in the region 7 having an upwardly convex shape is small, so that the temperature in the vicinity thereof is high.

  FIG. 4 shows the relationship between time and temperature at each position obtained by heat conduction calculation. FIG. 5 shows the relationship between time and temperature at each position from region 5 to region 7.

  4 and 5, each position is represented by a distance x to the highest point of the recess, starting from the lowest point of the recess of the donor substrate 101 (x = 0). (See FIG. 2).

  FIG. 6A shows a temperature distribution when the maximum temperature reaches 300 ° C. FIG. 6B shows the temperature distribution when the maximum temperature is reached (0.2 milliseconds from the start of heat generation).

  In the calculation results described in this embodiment, the same temperature is distributed in parallel to the surface of the light absorption layer 103, and the temperature decreases from the surface of the light absorption layer 103 along the depth direction.

101 Donor substrate 102 Base film 103 Light absorption layer 104 Organic material layer 105 Light 107 Organic material layer 107a Organic material layer 107b Organic material layer 108 Reflective layer 111 Substrate 121 Electrode 125 Insulator 122 Electrode

Claims (2)

The first substrate and the second substrate are opposed to each other,
A film forming method for forming a second layer above the second substrate by skipping organic substances contained in a first layer provided on a first surface of the first substrate,
The first surface has a plurality of recesses,
The concave portion has a curved shape,
A third layer having a function of absorbing light is provided so as to have a portion overlapping with the recess,
The first layer is provided so as to have a portion that overlaps the concave portion via the third layer,
Irradiating light from the second surface opposite to the first surface of the first substrate, the organic matter contained in the first layer is blown, and the second substrate is placed above the second substrate. Forming a second layer ;
The film forming method , wherein the curved surface shape is a partial shape of a cylindrical side surface . Having a plurality of recesses,
The concave portion has a curved shape,
A first layer having a function of absorbing light is provided so as to have a portion overlapping the concave portion
A second layer containing an organic substance is provided so as to have a portion overlapping the concave portion via the first layer ;
The substrate for transfer , wherein the curved surface shape is a partial shape of a cylindrical side surface .