JP2006344459A - Transfer method and transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer method and a transfer device wherein device configuration can be simplified and miniaturized. <P>SOLUTION: In the transfer method, first, a process overlapping the transfer substrate 20 wherein a luminous layer 23 is formed on one main surface side of a supporting substrate on a substrate 10 to be transferred is performed in such a state that the luminous layer 23 is directed to the substrate 10 to be transferred, then, a process making a vacuum atmosphere between the substrate 10 to be transferred and the transfer substrates 20 is performed in such a state that the transfer substrate 20 is overlapped on the substrate 10 to be transferred, and then, a process transferring the luminous layer 23 to the substrate 10 to be transferred is performed by irradiating the transfer substrate 20 with laser light from a laser light source 41 under the vacuum atmosphere. The transfer device 30 used for this transfer method is also disclosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transfer method and a transfer apparatus used therefor, and particularly to a transfer method and a transfer apparatus used for thermal transfer of a light emitting layer of an organic electroluminescent element (organic EL element).

  An organic electroluminescent element using electroluminescence of an organic material has an organic layer in which a hole transport layer and a light emitting layer are laminated between a lower electrode and an upper electrode, and is driven by a low voltage direct current drive. It attracts attention as a light emitting element capable of emitting light with high luminance.

A full-color display device using such an organic electroluminescent element has R (red), G (green),
B (blue) organic electroluminescent elements of respective colors are arranged on a substrate. In manufacturing such a display device, it is necessary to pattern-form a light emitting layer made of an organic light emitting material that emits light of each color for each light emitting element.

  As one method for forming the pattern of the light emitting layer, a transfer method using an energy source (heat source) (that is, a thermal transfer method) has been proposed. As the thermal transfer method, a transfer method in which a transfer substrate and a transfer substrate are transferred in close contact with each other via a transfer layer (see, for example, Patent Document 1), and the transfer substrate and the transfer substrate are separated from each other. There has been reported a separation method in which transfer is performed in a state (see, for example, Patent Document 2).

JP 2004-200170 A JP 2004-79540 A

  A transfer apparatus used for the thermal transfer method generally includes a vacuum chamber for performing a transfer process and an irradiation source for irradiating radiation for applying heat to a transfer substrate introduced into the vacuum chamber. For example, a movable holding member that holds the transfer substrate and the transfer substrate and moves in the vertical direction is disposed in the vacuum chamber. The transfer substrate holding member is arranged on the upper side of the vacuum chamber with respect to the transfer substrate holding member so that the transfer substrate and the transfer substrate face each other.

  Further, an opening that is slightly smaller than the transfer substrate is provided in the upper part of the vacuum chamber, and an airtight seal is provided on the periphery of the opening on the inner wall side of the upper part of the vacuum chamber. The transfer substrate closes the opening through the hermetic seal, so that the vacuum chamber can be hermetically sealed.

  On the other hand, the radiation source of the transfer substrate is disposed above the vacuum chamber, and is configured to apply heat to the transfer substrate. As the heat source, for example, there is a laser light source, and an XY scanner that performs scanning while irradiating the laser beam with a spot by moving the laser light source in the XY direction is disposed.

  In the case where the light emitting layer of the organic electroluminescent element is formed by using, for example, a contact thermal transfer method using the transfer device as described above, a hole injection layer is formed on the substrate of the display device via the lower electrode (anode), A hole transport layer is sequentially laminated to form a transfer substrate. On the other hand, a transfer substrate is formed by forming a light emitting layer on another substrate via a photothermal conversion layer (light absorption layer). Next, the transfer substrate and the transfer substrate are introduced into the vacuum chamber, and each holding member is placed so that the hole transport layer provided on the transfer substrate and the light emitting layer provided on the transfer substrate face each other. Installing.

  Next, the opening at the top of the vacuum chamber is closed with a gate valve from the outside to close the vacuum chamber, and then the inside of the vacuum chamber is decompressed to be in a vacuum atmosphere. Subsequently, the holding member holding the transfer substrate is moved upward to close the opening in the upper part of the vacuum chamber from the inside with the transfer substrate, and the holding member holding the transfer substrate is pushed up to transfer The substrate for transfer and the substrate to be transferred are overlaid. After that, when the gate valve is opened, the upper portion of the vacuum chamber including the transfer substrate is pushed from above by the atmospheric pressure, so that the transfer substrate and the transfer substrate are brought into close contact with each other. In this state, the light-emitting layer is thermally transferred onto the hole transport layer in a predetermined region with good positional accuracy by scanning the transfer substrate while irradiating it with laser light.

  On the other hand, when transferring by the thermal transfer method of the separation method, the basic configuration of the transfer device is the same, and the transfer substrate introduced into the vacuum chamber and the transfer substrate are opposed to each other with a certain distance. Deploy. Thereafter, the inside of the vacuum chamber is placed in a vacuum atmosphere, and the transfer substrate is transferred from the transfer substrate to the transfer substrate by irradiating the transfer substrate with laser light.

  However, according to the above-described close-contact transfer method, the transfer substrate and the transfer target substrate are placed in opposition to each other in a vacuum atmosphere, and then the transfer substrate and the transfer target substrate are overlapped. It is necessary to dispose a movable holding member that moves the transfer substrate in the vacuum chamber. Moreover, since each holding member maintains the said board | substrate in the state pushed up with respect to atmospheric pressure, the intensity | strength which can endure a load is required. This complicates and enlarges the configuration of the vacuum chamber, which increases the equipment cost. Furthermore, when forming the light emitting layer of the organic electroluminescent element in order to bring the transfer substrate and the transfer substrate into close contact with each other, there is a problem of contamination and damage of foreign matters in the pixels of the transfer substrate.

  The separation type transfer device also requires a movable holding member and a space for maintaining the transfer substrate and the transfer substrate in a separated state in the vacuum chamber, so that the structure of the vacuum chamber is complicated. Will become larger and larger.

  For this reason, there has been a demand for a transfer device and a transfer method that can simplify the apparatus configuration and can be miniaturized.

  In order to achieve the above-described object, the transfer method of the present invention is such that a transfer substrate having a transfer layer formed on one main surface side of a support substrate is first directed to the transfer substrate side. In this state, a process of superimposing on the transfer substrate is performed. Next, a process of creating a vacuum atmosphere between the transfer substrate and the transfer substrate is performed with the transfer substrate superimposed on the transfer substrate. Next, the transfer substrate is transferred to the transfer substrate by irradiating the transfer substrate with radiation in a vacuum atmosphere.

  According to such a transfer method, a vacuum atmosphere is formed between the transfer substrate and the transfer substrate after the step of superimposing the transfer substrate on the transfer substrate. Therefore, it is not necessary to provide a movable holding member for superimposing the transfer substrate and the transfer substrate.

  The transfer device of the present invention is a transfer device for transferring a transfer layer formed on a transfer substrate to a transfer substrate, and can be placed in a state where the transfer substrate is superimposed on the transfer substrate. A vacuum chamber having a mounting portion and storing the transfer target substrate and the transfer substrate in an overlapped state; and an irradiation source disposed above the vacuum chamber and irradiating the transfer substrate with radiation. ing. The vacuum chamber is configured to sandwich the substrate to be transferred and the transfer substrate placed in a state of being superimposed on the placement unit between the placement unit and the upper portion of the vacuum chamber. The mounting portion is fixed at a position where the transfer substrate and the transfer substrate are sandwiched.

  According to such a transfer apparatus, the vacuum chamber needs only to have a space for storing the transfer substrate and the transfer target substrate in an overlapped state. There is no need to provide a movable holding member for superposing the transfer substrate and the transfer substrate in an opposing manner. Further, even when compared with a conventional separation type transfer apparatus, a movable holding member and a space for maintaining the transfer substrate and the transfer substrate in a separated state are not required. For this reason, the configuration of the vacuum chamber is simplified and the volume can be reduced.

  As described above, according to the transfer method and transfer apparatus of the present invention, the configuration of the vacuum chamber is simplified and the volume of the vacuum chamber can be reduced as compared with the conventional transfer apparatus. Therefore, an increase in equipment cost can be prevented and the transfer device can be downsized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Implementation of applying the transfer method and transfer device of the present invention to a manufacturing method of a full-color display device in which organic electroluminescent elements of each color of red (R), green (G), and blue (B) are arranged on a substrate Will be described.

<Transfer substrate>
First, the transferred substrate will be described. FIG. 1A is an enlarged cross-sectional view of a main part illustrating a transfer substrate 10 used in the present embodiment, and FIG. 1B is an enlarged plan view of the main part. FIG. 1A is a cross-sectional view taken along the line XX ′ of FIG.

  First, as shown in FIG. 1A, after TFTs (thin film transistors) (not shown) are arrayed on a substrate 11 made of, for example, glass, for example, chromium (not shown) is interposed via an interlayer insulating film (not shown). A plurality of lower electrodes (anodes) 12 made of Cr) are pattern-formed for each pixel. Next, after forming a film of polyimide, for example, in a state of covering the lower electrode 12, an insulating layer 13 having a lattice shape in plan view for separating each pixel is formed through a first photolithography process. Thereby, each pixel A is formed in a strip-shaped pattern having a pitch P of 300 um / pixel.

  Next, through a second photolithography process, the upper portion of the insulating layer 13 is patterned to form a substantially rectangular parallelepiped protrusion 13a. Here, the protrusions 13a are formed on all the intersections of the grid-like insulating layer 13 over the entire pixel region where the pixels A are arranged (see FIG. 1B). At this time, the height h of the insulating layer 13 is 1 μm, and the height h ′ of the protrusion 13a is 2 μm.

  Here, the protrusion 13a functions as a spacer when the transfer substrate is superimposed on the transfer substrate 10 in a transfer process described later. As a result, even when the substrates are stacked, a space corresponding to the protrusion 13a is generated between the insulating layer 13 of the substrate to be transferred 10 and a light emitting layer provided on the transfer substrate described later. It communicates with the outside. For this reason, it is possible to create a vacuum atmosphere between the substrates after the substrates are stacked.

  Further, since the protrusion 13a is interposed when the transfer substrate is overlaid on the transfer substrate 10, the light emitting layer of the transfer substrate is prevented from coming into close contact with the pixel A. Damage to the inside and entry of foreign matter from the transfer substrate is prevented. Furthermore, since only the protrusion 13a is in contact with the light emitting layer of the transfer substrate, the light emitting layer of the transfer substrate can be reused.

  The present invention can be applied even when the protrusion 13a is not formed. However, when the protrusion 13a is formed, the space between the substrates can be communicated with the space outside the substrate in a state where the transfer substrate is superimposed on the substrate 10 to be transferred, and the substrate is reliably vacuumed. Since it can be set as an atmosphere, it is preferable. Furthermore, it is preferable because foreign substances can be prevented from entering and damaging the pixels of the transfer substrate from the transfer substrate by bringing the substrates into close contact with each other.

  Here, the example in which the protruding portions 13a are formed on all the intersecting portions in the lattice-like insulating layer 13 has been described. However, the protruding portions 13a are in a state where the transfer substrate and the transferred substrate 10 are overlapped. As long as it is possible to create a vacuum atmosphere between the substrates, it may not be provided on all the intersections, and may not be on the intersections. Furthermore, the protrusions 13a do not need to be provided in the pixel region. For example, the plurality of protrusions 13a may be arranged in a frame shape on the insulating layer 13 outside the pixel region. However, when the plurality of protrusions 13a are evenly arranged in the pixel region, the substrate to be transferred 10 and the transfer substrate in all regions of the pixel region in a state where the substrate to be transferred 10 and the transfer substrate are overlapped. The distance between and is maintained evenly. For this reason, the vacuum atmosphere can be surely formed between the substrates in all the pixel regions, which is preferable.

  Next, a hole injection layer 14 made of m-MTDATA [4,4,4-tris (3-methylphenylphenylamino) triphenylamine] is formed on the lower electrode 12 by using, for example, a vapor deposition method to a thickness of 25 nm. It is formed with a film thickness. Subsequently, it is made of α-NPD [4,4-bis (N-1-naphthyl-N-phenylamino) biphenyl], which is common to all the RGB pixels on the hole injection layer 14, for example, by vapor deposition. The hole transport layer 15 is formed with a film thickness of 30 nm.

  Although illustration is omitted here, the corner of the substrate 11 outside the pixel region formed by arranging a plurality of pixels A is used as a reference for alignment with a laser irradiation unit to be described later. A reference mark (not shown) is formed. As described above, the transfer substrate 10 is formed.

<Transfer substrate>
Next, the transfer substrate will be described. 2A and 2B are schematic views for explaining the transfer substrate 20 used in the present embodiment. FIG. 2A is a cross-sectional view, and FIG. 2B is a plan view.

  Here, a light-to-heat conversion layer (light absorption layer) 22 made of, for example, chromium (Cr) is formed to 200 nm on a glass support substrate 21 having one main surface side approximately the same size as the transfer substrate 10 by sputtering. The film thickness is formed. The photothermal conversion layer 22 converts laser light into heat when irradiating the transfer substrate 20 with laser light in a transfer step described later.

  Next, the light emitting layer 23 is formed with a film thickness of, for example, 25 nm on the photothermal conversion layer 22. In the present embodiment, in order to perform color display by emitting a plurality of display pixels R, G, and B arranged in a matrix on the transfer substrate 10 described above, for R, G, and B For each light emitting layer 23, a different material is used as an organic compound having a light emitting function. That is, at least three transfer substrates 20 are used for one transfer substrate 10.

  The red light emitting layer includes, for example, at least one of a red light emitting material, a hole transporting material, an electron transporting material, and a both charge transporting material. The red light emitting material may be fluorescent or phosphorescent. In this embodiment mode, the red light-emitting layer has a thickness of about 30 nm, and di (2-naphthyl) anthracene (ADN) is 2,6-bis [(4′-methoxydiphenylamino) styryl] -1,5- It is composed of 30% by weight of dicyanonaphthalene (BSN).

  In addition, the green light emitting layer includes, for example, at least one of a green light emitting material, a hole transporting material, an electron transporting material, and a charge transporting material. The green light emitting material may be fluorescent or phosphorescent. In the present embodiment, the green light-emitting layer has a thickness of about 30 nm in this example, and is configured by mixing 5% by weight of coumarin 6 with ADN.

  Furthermore, the blue light emitting layer contains, for example, at least one of a blue light emitting material, a hole transporting material, an electron transporting material, and a charge transporting material. The blue light emitting material may be fluorescent or phosphorescent. In the present embodiment, the blue light emitting layer has a thickness of about 30 nm, for example, and 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] biphenyl (DPAVBi) is added to ADN. Is mixed with 2.5% by weight.

  Here, the film-forming range of the light-to-heat conversion layer 22 and the light emitting layer 23 is on the substrate 11 (see FIG. 1A) when it is overlapped with the transfer substrate 10, as shown in FIG. An area that does not cover the reference mark provided at the corner is formed. As described above, the transfer substrate 20 is formed. Here, a glass substrate is used as the support substrate 21, but the present invention is not limited to this, and the support substrate 21 may be in the form of a film.

<Transfer device>
Next, the transfer device will be described with reference to FIG. As shown in this figure, the transfer device 30 is directed to a vacuum chamber 31 that can be accommodated in a state where the transfer substrate 20 is superimposed on the transfer substrate 10, and a transfer substrate 20 that is accommodated in the vacuum chamber 31. And a laser irradiation unit 40 for irradiating radiation.

  The vacuum chamber 31 includes a container-like base body 32 having an upper portion made of, for example, stainless steel and an upper portion opened, and a frame-like lid body 33 made of, for example, stainless steel disposed on the upper portion of the base body 32.

  The base 32 has a placement portion 34 that can be placed in a state where the transfer substrate 20 is stacked on the transfer substrate 10. The mounting portion 34 is configured integrally with the bottom portion of the base body 32. The container-like base 32 is configured to have a height that can accommodate the transfer target substrate 10 and the transfer substrate 20 placed in a state of being stacked on the placement portion 34.

  Further, the side wall 32b of the base 32 is connected to an exhaust port 35 connected to a vacuum pump (not shown) for bringing the inside of the vacuum chamber 31 into a vacuum atmosphere, and a leak for releasing the vacuum atmosphere in the vacuum chamber 31. A mouth 36 is provided. The exhaust port 35 is provided with a valve 35a, and the leak port 36 is provided with a valve 36a.

  Here, it is preferable that the side wall 32 b is provided with a space B interposed between the transfer target substrate 10 and the transfer substrate 20 placed in a state of being superimposed on the previous placement portion 34. As a result, in the transfer step described later, the space between the transfer substrate 10 and the transfer substrate 20 formed by the protrusions 13a provided on the transfer substrate 10 can be communicated with the space B. Then, by making the inside of the vacuum chamber 31 a vacuum atmosphere, the space between the substrates can be surely made a vacuum atmosphere via the space B. However, a smaller space B is preferable because the volume of the vacuum chamber 31 can be reduced.

  On the other hand, the frame-shaped lid 33 covers the base 32 and constitutes the upper portion of the vacuum chamber 31, and the opening 33 a constituting the frame of the lid 33 is provided slightly smaller than the transfer substrate 20. It has been. On the surface (inner wall surface) 33b facing the base body 32 in the lid 33, an airtight seal 37 is disposed on the outer edge and the periphery of the opening 33a.

  The vacuum chamber 31 composed of the base body 32 and the lid body 33 is configured such that the base body 32 and the lid body 33 are connected by, for example, one side of the lid body 33 and opened by lifting the opposite side. 33 is configured to be locked in the closed state. Here, the base body 32 and the lid body 33 are connected to each other on one side of the lid body 33, but the lid body 33 may be provided so as to slide on the base body 32, and is connected to the base body 32. It does not have to be.

  Here, as a characteristic configuration of the present invention, the vacuum chamber 31 is configured such that the transfer target substrate 10 and the transfer substrate 20 that are placed on the placement portion 34 are superposed on the placement portion 34. And the lid 33. That is, by placing the lid 33 on the transfer substrate 20 and the base body 32 placed on the placement portion 34 via the transfer substrate 10 via the airtight seal 37, the transfer substrate 20 is placed. Thus, the opening 33 a is closed, and an airtight space is formed by the transfer substrate 20, the lid 33, and the base 32. In this state, the inside of the vacuum chamber 31 is made into a vacuum atmosphere, whereby the lid 33 is pulled inside the vacuum chamber 31 and the transfer substrate and the lid 33 are pressed from above at atmospheric pressure. As a result, the transfer substrate 10 and the transfer substrate 20 placed in a state of being superimposed on the placement portion 34 are sandwiched between the placement portion 34 and the lid 33.

  The placement portion 34 is fixed at a position where the transfer substrate 10 and the transfer substrate 20 are sandwiched. Here, the mounting portion 34 is fixed by being configured integrally with the bottom portion of the base body 32. Accordingly, a movable holding member for holding the transfer target substrate 10 in the vacuum chamber 31 is not required as compared with the conventional transfer apparatus, and it can sufficiently withstand a load due to atmospheric pressure. Thereby, the structure in the vacuum chamber 31 is simplified.

  Further, the mounting surface 34 a of the mounting portion 34 is provided on the same plane as the bottom surface 32 a of the base 32, and the distance D between the mounting surface 34 a and the inner wall surface 33 a of the lid 33 is determined so that the transfer surface 10 and the transfer substrate 10 are transferred. Suppose that it is provided so that it may become substantially equivalent to thickness D 'of the state which piled up the board | substrate 20 for an object. As a result, the height (distance D) that defines the volume of the vacuum chamber 31 may be a minimum height required for placing the transfer substrate 20 on the transfer substrate 10 in a conventional manner. This is preferable because the volume of the vacuum chamber 31 can be reduced as compared with the transfer apparatus of FIG. However, in this case, since the airtight seal 37 is crushed when the inside of the vacuum chamber 31 is placed in a vacuum atmosphere, the thickness is negligible.

  A laser irradiation unit 40 is disposed above the vacuum chamber 31 as a radiation source. The laser irradiation unit 40 includes a laser light source 41 and an XY scanner 42 that moves the laser light source 41 in the X and Y directions while performing spot irradiation. Although not shown in the figure, the laser light source 41 is provided with an alignment camera adjacent thereto, and a reference mark provided on the transfer substrate 10 is taken in. The laser light source 41 and the transfer substrate 10 Can be aligned.

  Here, the laser light source 41 is used as the radiation source. However, the irradiation source is not limited to the laser light source 42, and a heat bar, a thermal head, or the like may be used. In this case, since heat is directly applied to the transfer substrate 20, it is not necessary to form the photothermal conversion layer 22 on the transfer substrate 20.

  In the transfer device 30 described above, it is assumed that, for example, three transfer devices 30 for transferring the light emitting layers 23 of the respective colors are arranged inside an external chamber 50 replaced with an inert gas. Accordingly, when the transferred substrate 11 after transfer is moved to a transfer device that transfers the light emitting layer 23 of another color, the organic layer including the light emitting layer 23 is not exposed to water or oxygen in the atmosphere. It is preferable because damage is prevented.

  Here, the example in which the substrate mounting surface is provided in the same plane as the bottom surface 32a of the base 32 has been described, but the stage portion for mounting the substrate on the bottom surface 32a of the base 32 is provided with a step. May be. However, it is preferable that the mounting surface of the substrate is provided in the same plane as the bottom surface 32 a of the base 32 because the volume of the vacuum chamber 31 can be reduced.

  Although an example in which the lid 33 is a frame will be described here, the lid 33 may be a plate-like member instead of a frame. In this case, in the transfer step to be described later, the transfer substrate 20 is irradiated with laser light through the lid 33. Therefore, the lid 33 is made of a transparent plate-like member such as glass. I will do it. However, it is preferable that the lid 33 is a frame because the transfer substrate 20 can be directly irradiated with laser light, so that the transmittance is good and the refractive index of the lid 33 is not affected. When the lid 33 is formed of a plate-like member, the transfer is performed with the substrate to be transferred 10 placed on the placement portion 34 in a state where the lid 33 is bent downward in a vacuum atmosphere. By sandwiching the transfer substrate 20, the entire area of the transfer substrate 20 is evenly pressed toward the transfer target substrate 10. For this reason, it is preferable that the side wall 32b of the base 32 is slightly higher than the upper surface of the transfer substrate 20 in a range where the lid 33 contacts the entire upper surface of the transfer substrate 20 in a vacuum atmosphere.

  Further, in the present embodiment, the example in which the vacuum chamber 31 is configured by the container-like base body 32 and the lid body 33 has been described. However, the present invention is not limited to this, and the vacuum chamber 31 is mounted. The portion 34 and the upper portion of the vacuum chamber 31 are configured to sandwich the transferred substrate 10 and the transfer substrate 20 in an overlapped state, and the mounting portion 34 is fixed at a position where the substrate is sandwiched. It only has to be. For example, it may be a vacuum chamber provided with a base made of a plate-like member and a box-like lid that closes in a state of covering the base, and the base and the lid are integrally formed. It may be a vacuum chamber into which the substrate can be introduced from the side wall side. Furthermore, a plurality of recesses that can be accommodated in a state where the transfer substrate 10 and the transfer substrate 20 are stacked are formed on the bottom surface of the external chamber 50 as described above, and a plate-like member that closes the recesses It may be a vacuum chamber provided with a lid made of

<Transfer process>
Next, a transfer method for transferring, for example, the red light emitting layer 23 (transfer layer) from the transfer substrate 20 to the transfer substrate 10 using the transfer apparatus 30 described above will be described. First, the substrate 10 to be transferred is placed on the placement portion 34 of the base 32 constituting the vacuum chamber 31 with the inside of the external chamber 50 in an inert gas atmosphere. At this time, as shown in FIG. 4A, the lower electrode 12 is placed with the formation surface side facing upward. Here, although not shown here, since the hole injection layer 14 and the hole transport layer 15 described with reference to FIG. 1A are sequentially stacked on the lower electrode 12, The surface becomes the hole transport layer 15.

  Next, the transfer substrate 20 is overlaid on the transfer substrate 10 with the formation surface side of the light emitting layer 23 provided on the transfer substrate 20 facing the transfer substrate 10 side. As a result, since the substrate to be transferred 10 is provided with a plurality of protrusions 13a, the transfer substrate 20 is supported by the protrusions 13a. In addition, a space C communicating with the outside is formed between the substrate to be transferred 10 and the transfer substrate 20 by the protruding portion 13a. At this time, as shown in the top view of FIG. 4B, the reference mark S provided at the corner of the transfer substrate 10 is confirmed through the transfer substrate 20.

  Here, the transfer substrate 10 and the transfer substrate 20 are overlapped in the base 32, but the transfer substrate 10 is transferred onto the transfer substrate 10 in the external chamber 50 in an inert gas atmosphere shown in FIG. After the substrate 20 is overlaid, the transfer substrate 10 and the transfer substrate 20 may be placed on the placement portion 34 in the overlaid state.

  Next, as shown in FIG. 3, the frame-shaped lid 33 is disposed and locked on the base 32 and the transfer substrate 20 through an airtight seal 37. As a result, the transfer chamber 20 closes the opening 33a of the lid 33, so that the vacuum chamber 31 is closed.

  Thereafter, the valve 35 a provided at the exhaust port 35 is opened, and the inside of the vacuum chamber 31 is depressurized. At this time, the lid 33 placed on the substrate 32 and the transfer substrate 20 via the airtight seal 37 is pulled inside the vacuum chamber 31, and the inside of the vacuum chamber 31 is in a vacuum atmosphere. Also, the lid 33 and the transfer substrate 20 are pushed toward the transfer substrate 11 by atmospheric pressure from above, and the transfer substrate 20 on the transfer substrate 10 is placed in a state of being supported by the protrusions 13a. It is sandwiched between the part 34 and the lid 33.

  In this state, the space B in the vacuum chamber 31 becomes a vacuum atmosphere, and the space C (see FIG. 4A) between the substrate to be processed 10 and the transfer substrate 20 communicating with the space B becomes a vacuum atmosphere. . At this time, since the light emitting layer 23 provided on the transfer substrate 20 is in contact only with the protrusion 13a, damage to the light emitting layer 23 is suppressed, so that the transfer substrate 20 is used for the second and subsequent transfers. Can be used. Further, since the protrusion 13a is interposed, adhesion between the transfer substrate 20 and the transfer substrate is prevented, so that the foreign matter from the transfer substrate 20 is detected by the pixel A of the transfer substrate 10 (see FIG. 4A). Reference)), the damage in the pixel A of the substrate 10 to be transferred due to the transfer substrate 20 is also suppressed.

  Next, the reference mark S (see FIG. 4A) of the substrate to be transferred 10 is taken into the alignment camera of the laser irradiation unit 40, thereby aligning the substrate to be transferred 10 and the laser light source 41, For example, an infrared laser beam of 800 nm is spot-irradiated from the laser light source 41 and absorbed by the photothermal conversion layer 22 of the transfer substrate 20. Then, using this heat, the light emitting layer 23 is selectively transferred onto the hole transport layer 15 formed on the substrate 10 to be processed. At this time, the cutting width of the infrared laser light is 100 μm.

  Here, the transfer process of selectively irradiating the spot-irradiated laser beam in the X and Y directions has been described, but only the portion that irradiates the laser beam between the laser irradiation unit 40 and the transfer substrate 20. A light-shielding mask (not shown) having an opening may be arranged to irradiate the entire surface with laser light.

  After the transfer is completed, the valve 35a of the exhaust port 35 is closed, and the valve 36a of the leak port 36 is opened, thereby covering the vacuum chamber 31 in a vacuum atmosphere to normal pressure. Thereafter, the lid 33 is opened, the transfer substrate 20 is moved away from the transfer substrate 10 and moved in the external chamber 50 under an inert gas atmosphere, and the transfer substrate 30 for B and G is transferred to the transfer substrate 10. To move. Thereafter, using the transfer substrate 20 corresponding to B and G, the blue light emitting layer and the green light emitting layer are also transferred in the same process.

  The subsequent manufacturing process is performed in the same process as the manufacturing method of a normal organic electroluminescent element. That is, the electron transport layer is formed on the light emitting layer 23 in a state where the entire display area is solid. The electron transport layer has a thickness of about 20 nm and is made of 8-hydroxyquinoline aluminum (Alq3).

  Subsequently, as an electron injection layer, lithium fluoride (LiF) is formed with a film thickness of about 0.3 nm (deposition rate˜0.01 nm / sec) by vacuum deposition, and then magnesium silver (MgAg) is formed as an upper electrode. ) Is formed with a film thickness of 10 nm by a vacuum deposition method. This cathode is formed as a common upper common electrode.

  At this time, the upper common electrode is formed by a film forming method in which the energy of the film forming particles is small enough not to affect the base, for example, a vapor deposition method or a CVD (chemical vapor deposition) method. Desirably, the upper common electrode is continuously formed in the same apparatus as the formation of the organic layer without exposing the organic layer to the atmosphere, thereby preventing deterioration of the organic layer due to moisture in the atmosphere. .

  In this case, the upper common electrode is formed transparently with a material having a low work function so that electrons can be efficiently injected into the organic layer. It is preferable to form as a metal thin film that can be formed by

  After the above, an insulating or conductive protective film is provided on the upper common electrode described above. In this case, a protective film is formed by, for example, a vapor deposition method or a chemical vapor deposition (CVD) method with a film formation method in which the energy of the film formation particles is small so as not to affect the base. In addition, the protective film is formed continuously in the same apparatus as the formation of the upper common electrode without exposing the upper common electrode to the atmosphere. Prevents deterioration of the organic layer due to moisture and oxygen.

  The protective film is formed with a sufficient film thickness using a material having low permeability and water absorption for the purpose of preventing moisture from reaching the organic layer. Further, when the display device is a top emission type, this protective film is made of a material that transmits light generated in the organic layer, and has a transmittance of, for example, about 80%.

  In particular, here, the protective film is formed of an insulating material, that is, the insulating protective film is directly formed on the upper common electrode having a single-layer structure made of a metal thin film.

  As such a protective film, an inorganic amorphous insulating material such as amorphous silicon (α-Si), amorphous silicon carbide (α-SiC), amorphous silicon nitride (α-Si1-x Nx) or amorphous carbon (α -C) and the like can be preferably used. Such an inorganic amorphous insulating material does not constitute grains, and thus has low water permeability and becomes a good protective film.

  For example, when forming a protective film made of amorphous silicon nitride, it is formed to a thickness of 2 to 3 μm by a CVD method. However, at this time, the film formation temperature is set to room temperature in order to prevent a decrease in luminance due to the deterioration of the organic layer, and further, film formation is performed under conditions that minimize film stress in order to prevent the protective film from peeling off. Is desirable.

  When the protective film is made of a conductive material, a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is used. After the protective film is formed as described above, a glass substrate is fixed on the protective film via an ultraviolet curable resin as necessary to complete the display device.

  According to the transfer method and the transfer apparatus as described above, a vacuum atmosphere is formed between the transfer substrate 20 and the transfer substrate 10 after the step of superimposing the transfer substrate 20 on the transfer substrate 10. The vacuum chamber 31 of the transfer device 30 used in this transfer method only needs to have a space for placing the transfer substrate 20 on the transfer target substrate 10. Accordingly, it is not necessary to provide a movable holding member for placing the transfer target substrate 10 and the transfer substrate 20 in the vacuum chamber 31 so as to face each other and to stack them in the vacuum chamber 31 as compared with a conventional close-contact transfer device. Further, as compared with a conventional separation type transfer apparatus, a holding member and a space for maintaining the transfer target substrate 10 and the transfer substrate 20 in a separated state are not required. For this reason, the configuration of the vacuum chamber 31 can be simplified and the volume of the vacuum chamber 31 can be reduced. Therefore, an increase in equipment cost can be prevented and the transfer device can be downsized.

  Further, since the configuration of the vacuum chamber 31 is simplified and the volume can be reduced, the distance between the transfer substrate 20 and the laser light source 41 can be made relatively short. For example, it is possible to use a light source that requires an objective condenser lens and has a limited focal length, such as a semiconductor laser, and the selectivity of the light source is expanded. Further, the shortening of the distance also improves the alignment accuracy between the light irradiation position and the transferred substrate. Furthermore, since a movable member for superimposing the transfer substrate 10 and the transfer substrate 20 can be disposed under a normal pressure environment, accessibility can be improved and maintenance can be improved.

  Further, since the protrusions 13 a are provided on the transfer substrate 10, the space between the substrates can be surely set in a vacuum atmosphere in a state where the transfer substrate 20 is superimposed on the transfer substrate 10. Therefore, the light emitting layer 23 can be transferred from the transfer substrate 10 with high positional accuracy.

  In the above embodiment, an example in which only the light emitting layer 23 of the organic layers constituting the organic electroluminescent element is formed by the thermal transfer method has been described. However, the present invention is not limited to the light emitting layer 23, and the hole injection layer 14, hole transport The present invention can be applied to other organic layers such as the layer 15 and the electron transport layer.

  In the present embodiment, the example of the method for manufacturing the top emission display device using the organic electroluminescence element has been described. However, the present invention is not limited to this, and the bottom emission type (transmission type) display is provided. It may be a device. In this case, the lower electrode 12 is formed using a highly transparent conductive material such as ITO, and the upper electrode is formed using a highly reflective conductive material.

  In the above embodiment, an example in which the lower electrode 12 is an anode and the upper electrode is a cathode has been described. However, the present invention can be applied to a display device in which the lower electrode 12 is a cathode and the upper electrode is an anode. is there. In this case, the light emitting layer 23 is formed in a state where the electron injection layer and the electron transport layer are laminated on the lower electrode 12.

  In the case where thermal transfer is performed using the transfer device 30 described above and a substrate thinner than the transfer target substrate 10 or the transfer substrate 20 used in this embodiment, the height of the bottom surface 32a of the base 32 is adjusted. A mounting plate (not shown) may be arranged, and the substrate 10 to be processed may be mounted on the mounting plate. In this case, the upper surface of the mounting plate is the mounting surface. Further, when thermal transfer is performed using the transfer apparatus 30 using a substrate that is thicker than the transfer target substrate 10 or the transfer substrate 20 used in the present embodiment, a frame-like shape having the same opening shape as the base 32 is used. It is also possible to separately arrange the constituent members on the base body 32 and adjust the height of the base body 32.

It is the principal part expanded sectional view (a) and principal part enlarged plan view (b) of the to-be-transferred substrate used for embodiment which concerns on the transfer method of this invention. It is a schematic diagram of the transfer substrate used in the embodiment according to the transfer method of the present invention, a sectional view (a) and a plan view (b). It is a section lineblock diagram for explaining an embodiment concerning a transfer device of the present invention. It is sectional drawing (a) and top view (b) for demonstrating embodiment which concerns on the transfer method of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Substrate to be transferred, 12 ... Lower electrode, 13a ... Projection, 20 ... Transfer substrate, 21 ... Support substrate, 23 ... Light emitting layer, 30 ... Transfer device, 31 ... Vacuum chamber, 32 ... Substrate, 32a ... Bottom surface, 33 ... lid, 33a ... opening, 33b ... inner wall surface, 34 ... mounting part, 34a ... mounting surface, 41 ... laser light source

Claims (8)

A step of superimposing a transfer substrate having a transfer layer formed on one main surface side of a support substrate on the transfer substrate in a state where the transfer layer faces the transfer substrate;
In a state where the transfer substrate is superimposed on the transfer substrate, a step of creating a vacuum atmosphere between the transfer substrate and the transfer substrate;
And a step of transferring the transfer layer onto the transfer substrate by irradiating the transfer substrate with radiation in a vacuum atmosphere. The transfer substrate supports the transfer substrate in a state where the transfer substrate is superimposed on the transfer substrate, and communicates with the outside between the transfer substrate and the transfer substrate. The transfer method according to claim 1, wherein a projecting portion that forms a space is provided. The substrate to be transferred is provided with an electrode on one main surface side of the substrate used for the organic electroluminescence device,
The transfer method according to claim 1, wherein the transfer layer is an organic layer including at least a light emitting layer. A transfer device that transfers a transfer layer formed on a transfer substrate to a transfer substrate,
A vacuum chamber that has a placement portion that can be placed in a state where the transfer substrate is overlaid on the transfer substrate, and stores the transfer substrate and the transfer substrate in the overlaid state;
An irradiation source that is disposed above the vacuum chamber and irradiates the transfer substrate with radiation;
The vacuum chamber is configured to sandwich the substrate to be transferred and the transfer substrate placed in a state of being superimposed on the placement unit between the placement unit and the upper portion of the vacuum chamber. And
The transfer device according to claim 1, wherein the placement unit is fixed at a position where the transfer substrate and the transfer substrate are sandwiched. The mounting portion has a mounting surface in the same plane as the bottom surface of the vacuum chamber, and the distance between the bottom surface and the inner wall surface of the upper portion of the vacuum chamber is determined by the transfer substrate and the transfer substrate. The transfer device according to claim 4, wherein the transfer device is provided so as to be substantially equal to a thickness in a state where the two are overlapped. The transfer apparatus according to claim 4, wherein the vacuum chamber includes a base body having the mounting portion described above and a lid that covers the base body and forms an upper portion of the vacuum chamber. The lid is a frame having an opening that is slightly smaller than the transfer substrate, and the opening comprises the frame by the transfer substrate placed on the placement portion via the transfer substrate. The transfer device according to claim 6, wherein an airtight space is formed by the transfer substrate, the lid, and the base body by closing the portion. The transfer apparatus according to claim 4, wherein the irradiation source is a laser light source.

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