JP5311985B2 - Vapor deposition apparatus and organic light emitting device manufacturing method - Google Patents

Description

  The present invention relates to a vapor deposition apparatus for depositing evaporated or sublimated material on a film formation target, and more particularly to an apparatus used for manufacturing an organic light emitting device.

  In recent years, in the manufacture of an organic light emitting display panel, it is required to increase the size of a substrate in order to reduce the manufacturing cost. Patent Documents 1 and 2 propose a vapor deposition apparatus using an evaporation source having a plurality of discharge ports in a discharge part as means for forming a uniform film on a large substrate.

  In manufacturing an organic light emitting display panel, a method of forming a film by placing a metal mask (hereinafter simply referred to as a mask) on a film forming surface of a substrate (mask forming method) is widely adopted. In order to manufacture a high-resolution organic light-emitting display panel, a mask having a high-definition pattern is used.

  When a high-definition mask is used to form a film with an evaporation apparatus, the substrate and the mask expand due to radiant heat from an evaporation source that is a heat source. Since the substrate and the mask are made of different materials, that is, often have different thermal expansion coefficients, the respective expansion amounts are different, and the relative positions of the substrate and the mask are shifted. As a result, there exists a problem that the precision of the vapor deposition pattern by a mask falls.

In particular, the evaporation sources described in Patent Document 1 and Patent Document 2 have a large amount of radiant heat due to the large area of the discharge portion provided with the discharge port, and the displacement of the relative position between the substrate and the mask also increases.
JP 2007-332458 A JP 2002-249868 A

  Therefore, if a heat shield member having an opening at a position corresponding to the emission port is installed so that the radiant heat from the vapor deposition source does not reach the substrate or the mask, the relative positional deviation between the substrate and the mask can be reduced. . By providing a water cooling mechanism on the heat shield member, a higher effect can be obtained.

  However, since the temperature of the heat shield member is lower than that of the vapor deposition source, the position of the opening of the heat shield member hardly fluctuates while the position of the discharge port greatly fluctuates due to thermal expansion. As a result, there is a risk that the discharge port may hit the heat shield member or be blocked by the heat shield member.

  When the discharge port collides with the heat shield member, the angle of the discharge port with respect to the substrate shifts and affects the film thickness distribution, or the temperature of the discharge port decreases due to heat transfer from the contact portion, and the material accumulates. Will be blocked. Further, when the discharge port is blocked by the heat shielding member, the vapor of the material does not reach the substrate, and a desired film thickness cannot be obtained.

  In particular, when the area of the discharge part is large, the amount of variation due to thermal expansion is larger in the discharge port arranged away from the place where the discharge part is fixed, and such a problem is likely to occur.

  The present invention has been made in view of the above points, and provides a vapor deposition apparatus capable of minimizing the amount of radiant heat from a vapor deposition source to a substrate and a mask while maintaining film thickness uniformity. In particular, an object of the present invention is to provide a vapor deposition apparatus suitable for manufacturing an organic light emitting device with high resolution and little quality variation.

  A material accommodating portion for accommodating the film forming material, a means for heating the material accommodating portion, a plurality of discharge ports for discharging vapor of the film forming material generated by heating, and the material accommodating portion to the respective discharge ports A vapor deposition apparatus comprising: a transport pipe for transporting a vapor of a film forming material; and a heat shield member having an opening at a position corresponding to each of the discharge ports, wherein each opening range of the heat shield member corresponds to The discharge port includes a range that varies in the horizontal direction due to thermal expansion.

  Furthermore, a method of manufacturing an organic light emitting device using the device, the step of determining a relative position between a substrate and a mask having a plurality of openings, and heating the vapor deposition source to the openings of the mask on the substrate And a step of forming a film having a corresponding pattern.

  According to the present invention, the amount of radiant heat from the vapor deposition source to the substrate is reduced, and the discharge port is thermally expanded to prevent the material from being deposited due to the temperature in the vicinity thereof being lowered due to contact with the heat shield member. Can do. Further, it is possible to prevent the discharge port from being blocked by the heat blocking member. Thereby, a stable and uniform film thickness can be formed. Furthermore, if the vapor deposition apparatus which concerns on this invention is used, manufacture of the organic light emitting element without a quality variation with high image quality will be attained.

  First, the whole vapor deposition apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an embodiment of a vapor deposition apparatus according to the present invention.

  The substrate 101 and the mask 102 are aligned in an alignment chamber (not shown), held by the substrate holding mechanism 103, and transferred into the film forming vacuum chamber 104. If the alignment chamber and the film-forming vacuum chamber 104 are previously depressurized to the same pressure, the alignment position can be prevented from shifting and the tact time can be reduced.

  In the film-forming vacuum chamber 104, there are arranged a material container 106 containing the film-forming material 105, a transport pipe 107 for transporting the vapor of the film-forming material 105 to the discharge unit 108, and a discharge port 109 for discharging the vapor. Yes. These are collectively referred to as a deposition source.

  The material container 106 is heated by a heating means (not shown) capable of controlling the temperature, and the temperature is adjusted to obtain a desired vapor deposition rate. A film thickness monitor 110 is disposed between the discharge port 109 and the mask 102 at a position that does not block the vapor flow of the vapor deposition material from the discharge port 109 toward the film formation surface of the substrate 101. The value of the vapor deposition rate calculated based on the film thickness measured by the film thickness monitor 110 is fed back to the temperature control unit of the heating means, and the temperature of the material container 106 is set so as to keep the vapor deposition rate constant. Adjusted.

  The transport pipe 107, the discharge portion 108, and the discharge port 109 through which the vapor of the film forming material 105 flows are provided with a superheating means and a thermocouple (both not shown). By these heating means and thermocouple, the path through which the vapor flows is controlled in the vicinity of the evaporation temperature of the film forming material so that the vapor of the film forming material 105 does not cool and aggregate or solidify inside the vapor deposition source.

  As a heating means for the vapor deposition source, a resistance heater, an induction heating coil, or the like can be used depending on the material of the vapor deposition source.

  Between the discharge port 109, the substrate 101, and the mask 102, a heat shield member 111 that blocks radiant heat from the vapor deposition source to the substrate is provided. The heat shield member 111 is preferably formed of a metal material having an emissivity of 0.1 or less in order to enhance the heat shield effect. For example, aluminum is one of the materials suitable for the heat shield member 111 in terms of low emissivity, low cost, and high workability. Furthermore, in order to further reduce the amount of radiant heat from the heat shield member 111 to the substrate 101, a cooling mechanism may be provided in the heat shield member 111. If the heat shield member is cooled too much, the temperature of the discharge port is lowered and the film forming material is deposited on the discharge port. Therefore, it is preferable to cool the heat shield member to about room temperature, and a water cooling pipe that allows water at about room temperature to flow through the heat shield member can be suitably used as the cooling mechanism.

  Next, the positional relationship between the discharge port of the vapor deposition apparatus according to the present invention and the heat shield member will be described in detail.

  The heat shielding member 111 is disposed so as to effectively use the material and obtain a uniform film thickness within the surface of the deposition target substrate. That is, it is arranged so as not to block the flow of vapor from all of the discharge ports 109 to the deposition target substrate, and the material discharged from the discharge ports 109 adheres to the heat shield member, or the discharge port 109 is caused by the adhered material. Arrange them so that they are not blocked. For this reason, it is preferable to dispose the tip of the discharge port 109 so as to protrude from the heat shield member 111.

  Each opening 112 provided in the heat shield member 111 is set so as to include a range in which the corresponding discharge port 109 varies in the horizontal direction due to thermal expansion. From the material of the heat shield member, the material of the vapor deposition source, the temperature reached by each member, the range in which each opening of the heat shield member varies due to thermal expansion, and the range in which each discharge port varies. Then, each opening range of the heat shield member is set so as to include a range in which the corresponding discharge port varies in the horizontal direction.

  At this time, if the opening range of the heat shield member 111 is set too large with an allowance, the effect of the heat shield member 111 blocking the radiant heat will be reduced. Therefore, it is preferable to set the difference between the range in which the discharge port fluctuates in the horizontal direction and the opening range as small as possible. However, errors in manufacturing the device, design errors, inclination of the entire discharge part due to piping distortion, etc. may occur. It is necessary to be able to cope with. Therefore, the opening range provided in the heat shield member is preferably provided with a margin of 1 to 5 mm with respect to the range in which the discharge port varies.

  Next, the arrangement of the discharge port 109 and the heat shield member 111 according to the present invention will be described with specific examples.

  FIG. 2 is a schematic view showing an example of a vapor deposition source in which the discharge port 109 is linearly arranged in the longitudinal direction of the discharge unit 108. The discharge part 108 is fixed to the transport pipe 107 at the center.

  The discharge ports 109 are provided at six locations symmetrically about the center of the discharge portion so that the film thickness distribution on the substrate is ± 3% or less in the calculation.

  The heat shield member 111 is disposed so that one opening 109 is included in each opening provided in the heat shield member.

  The tip of the discharge port 109 is disposed so as to protrude from the heat shield member 111 so that the flow of steam is not blocked by the heat shield member.

  The openings 112a, 112b, and 112c of the heat shield member 111 are set so as to include a range in which the discharge port 109 varies in the horizontal direction due to thermal expansion. Since the two discharge ports 109a closest to the center of the discharge part, where the discharge part is fixed to the transport pipe, have a small amount of fluctuation due to heat, the shape of the opening 112a corresponding to 109a is substantially circular.

  Since the amount of fluctuation due to heat at the two discharge ports 109b closest to the center of the discharge part next to the opening 112a increases in the longitudinal direction of the discharge part, the shape of the corresponding opening 112b is also substantially elliptical long in the long direction of the discharge part. It becomes a shape. Similarly, the shape of the two openings 112c farthest from the center of the discharge portion is also a substantially oval shape that is long in the longitudinal direction of the discharge portion.

  At this time, considering that the variation due to the thermal expansion of the discharge port is away from the center of the discharge portion, the discharge ports 109b and 109c are shifted from the center of the corresponding openings 112b and 112c toward the discharge portion center side at room temperature. Should be placed. In this way, the difference between the range in which the discharge port fluctuates in the horizontal direction and the opening range can be set even smaller, and the heat shield effect of the heat shield plate is also increased.

  FIG. 3 is a schematic view showing an example of a vapor deposition source in which discharge ports are two-dimensionally arranged on a plane. (A) is a perspective view of a vapor deposition source, (b) is the top view seen from the board | substrate side.

  The discharge ports 109 are provided at 10 positions symmetrically about the center of the discharge portion 108 so that the film thickness distribution on the substrate is ± 3% or less in the calculation.

  Since the discharge part 108 is fixed to the transport pipe 107 at the center, the position of each discharge port 112 varies radially in a direction away from the center of the discharge part due to thermal expansion. Accordingly, each opening 112 has a substantially oval shape in which a line connecting the center of the emitting portion 108 and the center of each opening 112 overlaps the major axis as shown in FIG. Since the position variation due to heat is larger in the discharge port located away from the center of the discharge portion, the major axis of the ellipse becomes large.

  Similarly to the case of FIG. 2, considering the direction in which the discharge port fluctuates due to thermal expansion, the discharge port changes when the discharge port is shifted from the center of the corresponding opening toward the center of the discharge portion at room temperature. The difference between the opening range and the opening range can be set smaller.

  As described above, the variation due to the thermal expansion of the discharge port has been described on the assumption that the discharge port is fixed to the transport pipe at the center. However, when it is fixed at a location other than the center of the discharge part, the variation due to thermal expansion is taken into account with the fixed location as a reference. In this case as well, a uniform film thickness can be obtained by making the opening smaller as it is closer to the fixed portion of the emission part and larger as it is farther away as in the embodiment. Further, the temperature rise of the substrate and mask is reduced, and high-precision patterning is possible.

  Subsequently, a film forming method will be described. Here, the case of the vapor deposition source shown in FIG. 3 will be described. Since the entire configuration can adopt the same configuration as that in FIG. 1, FIG. 1 is used.

After the substrate 101 is aligned with the mask 102 in an alignment chamber (not shown), the substrate 101 is held by the substrate holding mechanism 103 and carried into the film formation vacuum chamber 104. The alignment chamber and the film formation vacuum chamber 104 are evacuated to about 1 × 10 ⁻⁴ to 1 × 10 ⁻⁵ Pa by an unillustrated exhaust system.

  In the film formation vacuum chamber 104, the discharge port 109 and the film formation surface of the substrate 101 are arranged to face each other. The film forming material heated to vapor inside the material container 106 by a heat source (not shown) is discharged from the discharge port 109 through the transport pipe 107 and is deposited on the substrate 101 through the opening of the mask 102. Thereby, a film having a pattern corresponding to the opening pattern of the mask 102 can be formed on the substrate 101.

  The deposition rate is calculated by a film thickness monitor disposed between the discharge port 109 and the mask 102 at a position that does not block the flow of vapor from each discharge port 109 toward the film formation surface of the substrate 101. The deposition rate is fed back to a temperature control unit of a heating means (not shown) that heats the material container 106, and the heating temperature is adjusted. Thereby, a vapor deposition rate can be kept substantially constant.

  Hereinafter, an example of a manufacturing method using the vapor deposition apparatus according to the present invention will be described by taking an organic light emitting display panel as an example. However, the vapor deposition apparatus according to the present invention is not limited to this example, and is widely used in general vapor deposition. be able to.

(Example)
An organic light emitting display panel was manufactured by arranging the vapor deposition source shown in FIG. 2 in the vapor deposition apparatus shown in FIG. An organic light-emitting display panel having a light-emitting area size of 30 μm × 120 μm and a display area of 350 mm × 450 mm was prepared on a non-alkali glass substrate having a size of 400 mm × 500 mm using Alq3 as an organic compound.

  In the present embodiment, the deposition source needs to be heated to 330 to 360 ° C. in order to deposit Alq3 with a deposition rate of 10 [Å / s] and a film thickness of 1000 [Å]. Therefore, the temperature reached by the vapor deposition source was set to 360 ° C. to set the opening range of the heat shield member. The vapor deposition source and the transport pipe were made of stainless steel, and a water-cooled pipe was placed on the heat shield member 111, and water at about 26 ° C. was allowed to flow.

  Six discharge ports 109 are arranged at positions where the film thickness distribution on the substrate is ± 3% or less in the calculation so as to be symmetric with respect to the center of the discharge portion fixed to the transport pipe 107.

  The heat shield member 111 was disposed at a position where the tip of the discharge port 109 protrudes 2 mm from the heat shield member. Further, the heat shield member 111 is provided with openings 112a, 112b, and 112c so as to include a range in which the discharge port 109 fluctuates in the horizontal direction due to thermal expansion.

  The two openings 112a closest to the transport pipe 107 have a substantially circular shape, and the diameter thereof is the outer diameter of the discharge port 109 + 2 mm. The two openings 112b close to the transport pipe 107 next to the opening 112a have a substantially elliptical shape and are arranged so that the major axis is parallel to the line where the discharge port 109 is arranged. The short diameter of the opening 112b was the outer diameter of the discharge port +2 mm, and the long diameter was the outer diameter +4 mm. The center of the discharge port 109 was shifted from the center of the opening 112 by 1 mm toward the transport pipe along the major axis.

  The two openings 112c farthest from the transport pipe 107 are also substantially elliptical in shape so that the minor axis is perpendicular to the line where the discharge port 109 is arranged and the major axis is parallel. The short diameter was the outer diameter of the discharge port + 2 mm, and the long diameter was the outer diameter + 5 mm. The center of the discharge port 109 is also shifted from the center of the opening 112 by 1.5 [mm] along the long axis.

  First, a circuit 401 made of a thin film transistor (TFT) and electrode wirings were formed in a matrix on a glass substrate 402 using a known method. In order to alleviate the unevenness of the circuit 401 and the wiring, an acrylic resin was spin-coated to form a planarization layer 403 over the entire surface of the glass substrate 402 where the circuit 401 was formed. A plurality of contact holes 405 for electrically connecting the circuit 401 and a lower electrode 404 to be formed later are formed in the planarization layer 403.

  Next, a lower electrode 404 made of a laminate of Al and ITO was formed. First, Al was deposited by sputtering to a thickness of 70 nm, and then patterned by photolithography. Further, ITO was deposited by sputtering to a thickness of 70 nm and patterned by photolithography. As shown in FIG. 4, the lower electrode 404 and the circuit 401 are electrically connected through the contact hole 405.

  Subsequently, an acrylic resin was spin-coated on the surface provided with the lower electrode 404 to form an acrylic film having a thickness of about 2 μm, and a plurality of 30 μm × 120 μm size openings serving as light emitting regions were formed by photolithography. The acrylic film remaining on the substrate is called a bank 406, covers the hole of the contact hole 405 and the end of the lower electrode 404, and prevents a film to be stacked later from becoming discontinuous at the stepped portion. Hereinafter, the glass substrate 402 provided up to the bank is referred to as a substrate 101.

  Next, after aligning the mask 102 provided with a plurality of openings corresponding to the light emitting regions in the alignment chamber and the opening of the bank of the substrate 101, the mask 102 and the substrate 101 were held by the substrate holding mechanism.

  The mask 102 and the substrate 101 held by the substrate holding function were transferred into the film forming vacuum chamber 104 of the vapor deposition apparatus of FIG. In the film forming vacuum chamber, the film was transported at a constant speed of 4 [mm / sec] while being kept horizontal so that the distance from the discharge port 109 arranged in a line was 300 [mm]. The conveyance direction of the substrate is a direction perpendicular to the length of the vapor deposition source in FIG.

  The Alq3 film was formed with a target of a deposition rate of 10 [ｓ / s] and a film thickness of 1000 [Å]. The deposition rate was monitored by the film thickness monitor 110 and fed back to a heater control unit (not shown) that heats the material container 106 to control the heater temperature.

  At this time, the temperature of the material accommodating part 105 became substantially constant at about 340 degreeC. Further, the transport channel 107 to the discharge port 109 were controlled to be constant at about 330 ° C. by a heater and a thermocouple (not shown).

  Finally, ITO was deposited by sputtering to a thickness of 30 nm to form an upper electrode, thereby forming an organic light emitting display panel.

  As described above, when the vapor deposition apparatus according to the present invention is used to form the organic light emitting display panel, the radiation heat from the vapor deposition source is blocked by the heat shield member without contacting the discharge port and the heat shield member. I was able to finish. As a result, the organic light-emitting display panel was able to produce an organic light-emitting display panel having a light-emitting layer thickness distribution of about ± 2.0% and less variation in luminance and pixel defects.

The figure which shows an example of schematic structure of the vapor deposition apparatus concerning this invention. Schematic which shows one structural example of the vapor deposition source used for the apparatus apparatus concerning this invention. Schematic which shows one structural example of the vapor deposition source used for the apparatus apparatus concerning this invention. The schematic sectional drawing which shows an example of the organic light emission display panel manufactured using the vapor deposition apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Substrate 102 Mask 103 Substrate holding mechanism 104 Film-forming vacuum chamber 105 Film-forming material 106 Material housing part 107 Transport pipe 108 Release part 109 Release port 110 Film thickness monitor 111 Heat shield member 112 Opening 401 Circuit 402 Glass substrate 403 Flattening layer 404 Lower electrode 405 Contact hole 406 Bank 407 Light emitting layer 408 Electron transport layer 409 Electron injection layer 410 Upper electrode

Claims (5)

A material accommodating portion for accommodating a film forming material, a means for heating the material accommodating portion , a discharge portion having a plurality of discharge ports for discharging vapor of the film forming material generated by heating , and a fixing portion on the discharge portion A vapor deposition apparatus comprising: a transport pipe that transports vapor of the film forming material from the material accommodating portion to each of the discharge ports; and a heat shield member that has an opening at a position corresponding to each of the discharge ports. There,
The vapor deposition apparatus characterized in that each opening range of the heat shield member includes a range that fluctuates in a horizontal direction due to thermal expansion at a temperature reached by a corresponding discharge port, and is larger as the distance from the fixing portion increases . The vapor deposition apparatus according to claim 1, wherein a length along a line connecting the center of the opening and the fixing portion in the opening range becomes longer as the center of the opening and the fixing portion are separated from each other. The vapor deposition apparatus according to claim 1, wherein the discharge port is disposed near the fixed portion of the opening range of the corresponding opening at normal temperature. The vapor deposition apparatus according to any one of claims 1 to 3, wherein a tip of the discharge port is provided so as to protrude from the heat shield member. A method for manufacturing an organic light emitting device using the device according to claim 1, wherein a relative position between a substrate and a mask having a plurality of openings is determined, and the material container is heated. Forming a film having a pattern corresponding to the opening of the mask on the substrate.

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