KR100812027B1 - Laser induced transfer imaging and fabricating method of organic light emitting diode using the same - Google Patents

Abstract

In the present invention, when a light emitting layer is formed on a substrate by a laser thermal transfer method, a hole injection layer (HIL), a hole transfer layer (HTL) and an emitting layer (EML) are directed toward a donor film. The present invention relates to a laser thermal transfer apparatus capable of preventing detachment and a method of manufacturing an organic light emitting device using the same. In the laser thermal transfer apparatus forming the light emitting layer of the organic light emitting device according to the present invention, a donor film having an acceptor substrate on which a pixel region of the organic light emitting element is formed and a light emitting layer to be transferred to the pixel region is sequentially transferred and stacked. A substrate stage; A laser oscillator for irradiating a laser onto the donor film; A pressure regulator installed outside the chamber in contact with the substrate stage and maintaining a uniform pressure between the acceptor substrate and the donor film; And a chamber having at least the substrate stage therein. By such a configuration, color mixing does not occur and color uniformity can be improved.

Laser Thermal Transfer, Pressure Regulator, Donor Film

Description

LASER INDUCED TRANSFER IMAGING AND FABRICATING METHOD OF ORGANIC LIGHT EMITTING DIODE USING THE SAME}

1 is a schematic cross-sectional view of a laser thermal transfer apparatus according to the prior art.

2 is a view showing a defective pixel region during laser thermal transfer according to the prior art.

3 is a schematic cross-sectional view of a laser thermal transfer apparatus according to the present invention.

4A to 4D are cross-sectional views illustrating a method of transferring a light emitting layer according to the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

310: chamber 320: substrate stage

330: laser oscillator 340: substrate

350: donor film 370: pressure regulator

The present invention relates to a laser thermal transfer apparatus and a method for manufacturing an organic light emitting device using the same, and more particularly, when forming a light emitting layer on a substrate by a laser thermal transfer method, a constant pressure between the donor film and the substrate as a pressure control device. Laser thermal transfer which prevents the above vacuum from being caught and prevents the hole injection layer (HIL), the hole transfer layer (HTL) and the emitting layer (EML) from being released toward the donor film An apparatus and a method of manufacturing an organic light emitting device using the same.

Among the methods of forming the organic film layer, the deposition method is a method of forming an organic film layer by vacuum depositing an organic light emitting material using a shadow mask, and it is difficult to form a high-definition fine pattern by deformation of the mask. Difficult to apply

In order to solve the problem of the vapor deposition method, an inkjet method of directly patterning an organic film layer has been proposed. The inkjet method is a method in which an organic film layer is formed by dissolving or dispersing a light emitting material in a solvent and discharging it from a head of an inkjet printing apparatus as a discharge liquid. The inkjet method has a relatively simple process, but has a problem of low yield and nonuniformity in film thickness, which is difficult to apply to a large-area display device.

On the other hand, a method of forming an organic film layer using a laser thermal transfer method has been proposed. In the laser thermal transfer method, a donor film including a substrate, a light-heat conversion layer, and a transfer layer is irradiated with a laser to convert a laser beam passing through the substrate into a heat in the light-heat conversion layer to expand the light-heat conversion layer. The transfer layer is bonded to the acceptor substrate by expanding the adjacent transfer layer. Laser thermal transfer is a laser-induced imaging process with inherent advantages such as high resolution pattern formation, film thickness uniformity, multilayer lamination capability, and scalability to large motherboards.

When the laser thermal transfer method is conventionally performed, the inside of the chamber where the transfer is performed is preferably performed in a vacuum state so as to be synchronized with the deposition process when forming the organic light emitting device. However, when laser thermal transfer is performed in a conventional vacuum state, there is a problem in that the pressure is not uniform between the donor film and the acceptor substrate, so that the transfer characteristics of the transfer layer are poor. Therefore, in the laser thermal transfer method, a method of laminating a donor film and an acceptor substrate has an important meaning, and various methods for solving the problem have been studied.

Hereinafter, a conventional laser thermal transfer apparatus will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a laser thermal transfer apparatus according to the prior art.

Referring to FIG. 1, the laser thermal transfer apparatus 100 includes a substrate stage 120 positioned inside the chamber 110 and a laser irradiation apparatus 130 positioned above the chamber 110.

The substrate stage 120 is used to sequentially position the acceptor substrate 140 and the donor film 150 introduced into the chamber 110. The substrate stage 120 includes the acceptor substrate 140 and the donor film ( The first mounting groove 121 and the second mounting groove 123 are formed to align the 150, respectively. The first mounting groove 121 is formed along the circumferential direction of the acceptor substrate 140, and the second mounting groove 123 is formed along the circumferential direction of the donor film 150. Typically, since the acceptor substrate 140 has a smaller area than the donor film 150, the acceptor substrate 140 has a smaller first mounting groove 121 than the second mounting groove 123.

At this time, the first mounting groove 121 and the first mounting groove 121 and the first, without maintaining the vacuum inside the chamber 110 is made of laser thermal transfer in order to lamination without foreign matter or space between the acceptor substrate 140 and the donor film 150 2 pipes 161 and 163 are connected to a lower section of the mounting groove 123 and are sucked with a vacuum pump P to laminate the acceptor substrate 140 and the donor film 150.

However, in the vacuum pump P, the lamination of the acceptor substrate 140 and the donor film 150 at an uneven pressure causes the hole injection layer and the hole transport layer 141 on the acceptor substrate 140 to detach. Alternatively, the light emitting layer 151 on the donor film 150 may be detached to cause a mixed color defect in the light emitting area.

2 is a view showing a defective pixel area during laser thermal transfer according to the prior art.

As shown in FIG. 2, a circular defect A of 1 to 3 mm occurs mainly in the outer region Edge of the substrate. This is because when laminating the donor film and the acceptor substrate, a vacuum is taken from the outer region of the acceptor substrate so that a difference in the degree of vacuum occurs on the outer and inner sides of the acceptor substrate. When the degree of vacuum of the outer side of the acceptor substrate is maintained in a high state, there is a problem in that the hole injection layer, the hole transport layer, and the light emitting layer are detached from the outer region of the acceptor substrate due to the influence of the vacuum degree.

Accordingly, the present invention is an invention designed to solve the above-mentioned conventional problems, and an object of the present invention is to form a hole injection layer (HIL), a hole when a light emitting layer is formed on a substrate by a laser thermal transfer method. The present invention provides a laser thermal transfer apparatus capable of preventing the transport layer (HTL) and the emitting layer (EML) from being detached toward a donor film, and a method of manufacturing an organic light emitting device using the same.

In order to achieve the above object, according to the present invention, there is provided a laser thermal transfer apparatus for forming a light emitting layer of an organic light emitting device, comprising: an acceptor substrate on which a pixel region of the organic light emitting device is formed and a light emitting layer to be transferred to the pixel region; A substrate stage on which the donor film is sequentially transported and stacked, a laser oscillator for irradiating a laser to the donor film, and an outer side of the chamber in contact with the substrate stage, and having a uniform pressure between the acceptor substrate and the donor film. And a chamber including at least the substrate stage therein.

Preferably, the chamber includes a vacuum line for maintaining the interior in a vacuum, the pressure regulator is disposed in the vacuum line. The donor film may include a base substrate, a light-to-heat conversion layer, and a light emitting layer, and further include an intercalation layer between the light-to-heat conversion layer and the light emitting layer.

Further, in the method of manufacturing an organic light emitting device in which a light emitting layer is formed between a first electrode layer and a second electrode layer by a laser thermal transfer method according to the present invention, an acceptor for positioning an acceptor substrate having a pixel region formed on a substrate stage A substrate transfer step, a donor film transfer step of transferring a donor film having a light emitting layer on the acceptor substrate, and the acceptor substrate and the donor film are bonded to each other while maintaining a uniform pressure throughout the pixel region with a pressure adjusting device. And a transfer step of transferring the light emitting layer to the pixel area of the acceptor substrate by irradiating a laser to the donor film.

Preferably, a hole transport layer is further formed between the first electrode layer and the light emitting layer.

Hereinafter, with reference to the drawings showing an embodiment of the present invention will be described in detail a laser thermal transfer apparatus and a method of manufacturing an organic light emitting device using the same.

3 is a schematic cross-sectional view of a laser thermal transfer apparatus according to the present invention.

As shown in FIG. 3, the laser thermal transfer apparatus includes a chamber 310, a substrate stage 320, a laser oscillator 330, and a pressure regulator 370.

The chamber 310 may use a chamber 310 used in a conventional laser thermal transfer apparatus, and transfer the donor film 350 and the acceptor substrate 340 to the chamber 310 outside the chamber 310. Transfer means (not shown) for the robot arm is provided.

On the other hand, the substrate stage 320 is located on the inner bottom surface of the chamber 310, the substrate stage 320 may be further provided with a driving means (not shown) for moving. For example, when the laser is irradiated in the longitudinal direction, it may further include a drive means for moving the substrate stage 320 in the horizontal direction.

In addition, the substrate stage 320 may include respective mounting means for receiving and mounting the acceptor substrate 340 and the donor film 350. The mounting means allows the acceptor substrate 340, which has been transferred into the chamber 310 by the transfer means, to be accurately mounted at a predetermined position of the substrate stage 320.

In the present embodiment, the mounting means may include a through hole (not shown), a guide bar (not shown), movable plates 361 and 363, a support (not shown), and mounting grooves 321 and 323. have. At this time, the guide bar moves up or down in conjunction with the moving plates 361 and 363 and the support, and the guide bar moves up through the through-hole to accommodate the acceptor substrate 340, and descends to accept the acceptor substrate 340. ) Is mounted on the mounting grooves 321 and 323. At this time, it is preferable that the mounting grooves 321 and 323 have an oblique wall surface for accurate mounting of the acceptor substrate 340 and the donor film 350.

The laser oscillator 330 may be installed outside or inside the chamber 310, and the laser oscillator 330 may be installed to allow the laser to shine from above. In addition, the laser oscillator 330 uses a CW ND: YAG laser (1604 nm), includes two galvanometer scanners, and includes, but is not limited to, a scan lens and a cylinder lens.

The donor film 350 may be formed on a base film 353, a light to heat conversion layer (LTHC) 352 formed on the base substrate 353, and on the light-heat conversion layer 352. The light emitting layer 351 is formed on the substrate. An interlayer insertion layer (not shown) may be further included between the light-to-heat conversion layer 352 and the light emitting layer 351.

Referring to the donor film 350 in detail, the substrate 353 serves as a support and uses a substrate having a light transmittance of 90% or more. Polyester, polycarbonate, polyolefin, polyvinyl resin, or the like is used as a material for forming the base substrate 353. Among them, polyethylene terephthalate (PET) having excellent transparency is most used.

The light-to-heat conversion layer 352 serves to provide transfer energy capable of transferring the light emitting layer 351 onto a receptor such as an acceptor substrate 340, and absorbs a laser to convert the heat absorber into heat energy. radiation absorber). In the case where the light-to-heat conversion layer 352 is formed too thin, the energy absorption rate is low, the amount of energy converted into heat is small, the expansion pressure is low, and the transmitted energy is increased, thereby damaging the substrate circuit of the organic light emitting element. Since it gives, it is formed about 1㎛ to 5㎛.

The light-to-heat conversion layer 352 is formed in a thin film form using metallic and metal compounds. More specifically, it can be formed by dry methods such as sputtering and evaporative deposition, and the granular coating can be formed using a binder and any suitable dry or wet coating method. An interlayer insertion layer (not shown) for protecting the light-to-heat conversion layer 352 serves to prevent foreign substances of the light-to-heat conversion layer 352 from entering the light emitting layer 351.

The pressure regulator 370 is attached to a vacuum line that maintains a vacuum inside the chamber 310, and adjusts the degree of vacuum so as not to rise above a certain degree of vacuum. According to the present invention, by laminating by applying a uniform pressure between the donor film 350 and the acceptor substrate 340 through the pressure regulator 370, rather than a method of directly sucking the vacuum from the pump (P), Desorption of the hole injection layer / hole transport layer 341 and the light emitting layer 351 in the outer region can be prevented.

4A to 4D are cross-sectional views illustrating a method of transferring a light emitting layer according to the laser thermal transfer method of the present invention.

As shown in FIG. 4A, when the structure of the thin film transistor 207 formed on the substrate 200 is briefly described, a buffer layer 201 is formed on the substrate 200, and a portion of the buffer layer 201 is formed. A semiconductor layer 202 including an LDD layer (not shown) is formed between the active channel layer 202a and the ohmic contact layer 202b. The gate insulating layer 203 and the gate electrode 204 are patterned on the semiconductor layer 202 and sequentially formed. The interlayer insulating layer 205 formed on the gate electrode 204 and formed to expose the ohmic contact layer 202b of the semiconductor layer 202 and the exposed ohmic contact layer 202b. Source and drain electrodes 206a and 206b are formed on one region of the insulating layer 205.

In addition, a planarization layer 208 is formed on the thin film transistor 207, and one region of the planarization layer 208 is etched on the planarization layer 208 so that any one of the source and drain electrodes 206a and 206b may be etched. One of the source and drain electrodes 206a and 206b and the first electrode layer 209 are electrically connected through a via hole (not shown) formed so that one is exposed. The first electrode layer 209 is formed in one region of the planarization layer 208, and a pixel definition layer 210 is formed on the planarization layer 208.

An opening 218 is formed to etch one region of the pixel definition layer 210 so that the first electrode layer 209 is at least partially exposed. When the openings 218 are formed, they are etched using a photoresist process. A photoresist is uniformly coated on one region of the pixel definition layer 210 and selectively exposed and developed to form a photoresist pattern, and the pixel definition layer 210 is used as a mask. Is selectively etched and the unnecessary photoresist layer is removed by etching solution.

As shown in FIG. 4B, a hole transport layer 211 is formed on the pixel definition layer 210 and the opening 218. The hole transport layer 211 is formed by vacuum deposition using a mask. As the mask, a metal mask manufactured by processing a semiconductor such as SUS, Ni, Fe, Ni alloy (for example, Ni-Fe alloy) or silicon having a thickness of about 0.1 mm by etching or the like is generally used. .

Next, as shown in FIG. 4C, the donor film 215 is positioned on the substrate 200, and the laser is irradiated on the donor film 215 in the region where the light emitting layer 214 is to be transferred. As the light-to-heat conversion layer 213 of the portion irradiated with the laser on the donor film 215 expands, the light emitting layer 214 expands and is separated from the donor film 215 and patterned onto the substrate 200. The light emitting layer 214 is transferred to one region and the opening 218 of 211.

When the substrate 200 and the donor film 215 are aligned, a pressure regulator attached to a vacuum line prevents a vacuum above a predetermined pressure from being applied between the substrate and the donor film 215. Laminate at a uniform pressure.

Thereafter, as shown in FIG. 4D, when the light emitting layer 214 is transferred to the substrate 200, the donor film 215 and the substrate 200 are separated. On the separated substrate 200, the light emitting layer 214 is transferred along the uneven surface 220 and the opening 218 of one region of the hole transport layer 211, and the laser is irradiated from the light emitting layer 214 under the donor film 215. Only the light emitting layer 214 of the region is transferred, and the light emitting layer 214 of the region not irradiated with the laser remains on the donor film 215.

Therefore, when the donor film and the substrate are laminated, the pressure is uniformly applied by the pressure regulating device, whereby a hole injection layer (HIL), a hole transfer layer (HTL) and an emission layer (EML) are emitted. It is possible to prevent the phenomenon of detachment toward the donor film.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, when the light emitting layer is formed on the substrate by the laser thermal transfer method, a hole injection layer (HIL) is prevented by applying a pressure or higher pressure between the donor film and the substrate by the pressure adjusting device. By preventing the separation of the hole injection layer (HTL), the hole transfer layer (HTL) and the emitting layer (EML) toward the donor film, color uniformity may be improved since color mixing does not occur.

Claims (7)

In the laser thermal transfer apparatus for forming a light emitting layer of the organic light emitting element in the chamber, A substrate stage on which an acceptor substrate having a pixel region of the organic light emitting element and a donor film including a light emitting layer to be transferred to the pixel region are sequentially transferred and stacked; A moving plate for transferring the acceptor substrate and the donor film onto the substrate stage; A laser oscillator for irradiating a laser onto the donor film; A vacuum line having one end disposed outside the chamber and the other end disposed inside the chamber, the vacuum line maintaining the inside of the chamber in a vacuum state; And A laser is provided on the vacuum line disposed outside the chamber, the pressure adjusting device for maintaining the vacuum degree inside the chamber by performing the opening and closing operation according to the degree of vacuum in the chamber; Heat transfer device. delete delete The laser induced thermal imaging apparatus according to claim 1, wherein the donor film comprises a base substrate, a light-to-heat conversion layer, and a light emitting layer. The laser induced thermal imaging apparatus according to claim 4, wherein the donor film further comprises a hole transport layer between the light-to-heat conversion layer and the light emitting layer. In the method of manufacturing an organic light emitting device in which the light emitting layer is formed between the first electrode layer and the second electrode layer by the laser thermal transfer method in the chamber, An acceptor substrate transfer step of positioning an acceptor substrate having a pixel region on the substrate stage; A donor film transfer step of transferring a donor film having a light emitting layer on the acceptor substrate; It is provided on the vacuum line disposed outside the chamber, uniformly over the entire pixel area by using a pressure control device to maintain the vacuum degree uniformly in the chamber by performing the opening and closing operation according to the vacuum degree inside the chamber. Lamination step of bonding the donor film to the acceptor substrate by maintaining pressure; And And a transfer step of transferring the donor film to the pixel area of the acceptor substrate by irradiating a laser to the donor film. The method of claim 6, wherein a hole transporting layer is further formed between the first electrode layer and the light emitting layer.

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