JP2010272229A - Method for manufacturing transparent electrode of organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a film effectively without the need to change pressure inside a vacuum tank or input power to an electrode at sputtering deposition while restraining damage to an organic thin film on a substrate to the minimum. <P>SOLUTION: In soft deposition, a shutter 5 is arranged to face to a target 8, and a substrate 3 is conveyed to a side part of the shutter 5 by a substrate convey mechanism 4. In that state, target particles leaked slightly from a side of the shutter 5 are made collide to the substrate 3 to carry out soft deposition. After soft deposition, the substrate 3 is conveyed to a back part of the shutter 5 by the substrate convey mechanism 4 to carry out high-rate deposition through movement of the shutter 5. In this state, a discharge space facing to the target electrode 2 is spread downward of the substrate 3, target particles, recoil ions and γ electrons in high-energy state collide to the substrate 3 in large quantity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a transparent electrode of an organic electroluminescent element (organic EL element), and more particularly to a production method using a sputtering method.

  An organic EL element formed by sequentially laminating a transparent electrode, an organic light emitting layer, and a metal electrode on a substrate is subjected to a sealing process in order to prevent deterioration due to moisture in the atmosphere. Sealing is performed by can sealing or film sealing, but development of film sealing is the mainstream due to the trend of lightening and flexibility of elements.

  By the way, for the production of film sealing, a dry process is preferred because of the nature of the organic EL element. Specifically, thin film formation techniques such as vacuum deposition and sputtering are used.

  5 (a) and 5 (b) are explanatory views showing an example of moving film formation in a vertical vacuum apparatus for performing conventional sputtering. The white arrow in the figure indicates the direction in which the substrate 3 advances as the process advances.

  5 (a) and 5 (b), a target electrode 2 and a substrate transport mechanism 4 for transporting the substrate 3 are provided in the vacuum chamber 1, and the target is adjusted in the vacuum chamber 1 to a predetermined gas pressure. By applying a voltage to the electrode 2, plasma 6 is generated and the target 8 on the target electrode 2 is sputtered to form a sealing film on the substrate 3.

  Since the discharge is not stable at the beginning of the discharge, or a natural oxide film left on the surface of the target 8 when it is opened to the atmosphere by the previous film formation process, the film quality on the substrate 3 is not good. For this reason, the shutter 5 is often used to shield the initial target particles from the substrate 3.

  FIG. 5A shows a schematic arrangement of the target electrode 2, the substrate 3 and the shutter 5 before film formation. The plasma 6 and the target are disposed above the target electrode 2 (between the target electrode 2 and the shutter 5). The particle scattering range 7 is widened. Prior to film formation, the substrate 3 stands by at a position outside the target particle scattering range 7 due to the shielding effect of the shutter 5 or the like.

  FIG. 5B shows a schematic arrangement of the target electrode 2, the substrate 3, and the shutter 5 during film formation. During film formation, the shutter 5 is positioned outside the target particle scattering range 7 with respect to the substrate 3. The substrate 3 is disposed at a position facing the target electrode 2 and deposited.

  When the film formation is completed, the discharge is stopped and the substrate transport mechanism 4 is used to transport the substrate 3 to the next step downstream in the transport direction.

  However, in the case of forming an inorganic film having a good sealing property in an organic EL element by sputtering, it is a problem that the organic EL element is deteriorated due to an attack by high energy particles on the film formation surface. Various measures for preventing this deterioration have been studied.

For example, in Patent Document 1, when forming a conductive thin film on the surface of an organic thin film formed on a substrate, the initial pressure in the vacuum chamber is set to 1.33 × 10 ⁻² Pa or less, and electrons incident on the substrate By reducing the existence probability of ions, damage to the organic thin film is reduced, and since the film formation rate is low as it is, the first layer is formed at a somewhat low rate, and then sputtering gas is introduced into the vacuum chamber. A technique is disclosed in which the second layer is formed by increasing the film formation rate by increasing the plasma density of the target surface by flowing a large amount (adjusting the pressure). Thereby, the first layer can be formed softly and the second layer can be formed in a short time.

  In addition, by controlling the input power and setting the sealing film to a low value at the beginning of applying the sealing film, and gradually increasing it, the initial film softly formed with particles having a low sputtering energy results in a high sputtering energy thereafter. A method for protecting the element from the particles is also conceivable.

  In Patent Document 2, the distance between the target electrode unit and the substrate transported by the transport mechanism in the vacuum chamber is reduced continuously or stepwise from the substrate transport upstream side to the substrate transport downstream side. Has been proposed.

  According to the above method, when sputtering is performed, the distance between the substrate to be transported and the target gradually decreases as the substrate is transported downstream in the transport direction, so that the deposition time elapses on the substrate. From the state where the film formation rate of the sputtering film is low and soft film formation is possible, the film formation rate is gradually increased to the state where a desired film thickness can be formed in a short time.

  Therefore, at the beginning of film attachment, that is, for example, a film-forming material adhering immediately above an organic thin film previously formed on a substrate is softly formed so as not to damage the organic thin film, and then a high rate is obtained. (The material deposited softly on the organic thin film etc. does not directly collide with the organic thin film, and the organic thin film is protected) .

  As a result, good film formation can be achieved in a short time, and of course, there is no need to change the gas pressure in the vacuum chamber and the input power to the electrodes as in the conventional case, and the degree of vacuum, plasma or voltage can be stabilized. It is said that production tact time can be shortened by the amount of time required.

JP 2005-340225 A JP 2008-63616 A

  However, when the pressure in the vacuum chamber is adjusted as disclosed in Patent Document 1, depending on the capacity of the vacuum chamber, by adjusting the pressure, it is possible to stabilize the time required to reach a predetermined degree of vacuum and plasma. The time required is in units of several tens of seconds. For this reason, the total production tact time increases in minutes.

  Currently, in an organic EL element manufacturing apparatus, for example, a tact time from when a substrate on which a transparent electrode (ITO) is formed to when an organic light emitting layer, a metal electrode, and a sealing film are formed and carried out Is required for 3-5 minutes. For this reason, an increase in tact time in minutes is a major problem in actual production, and new implementation means are demanded.

  Even when the input power is gradually changed as in the prior art, it takes time to stabilize the voltage, the sputtering state becomes unstable, and the quality of the sealing film is lowered, which is difficult in reality.

  In addition, as disclosed in Patent Document 2, when the damage is adjusted by the distance between the substrate in the vacuum chamber and the target, the substrate is transported in one direction with respect to the target, so the orientation of the film attached to the substrate Is biased.

  Even if another similar target is attached in a different manner, the film is formed as a low-damage film → high-damage film → low-damage film, and the desired film structure (low-damage film from the side close to the EL layer) (→ Highly damaged film) Even if it is a film that can withstand use, an extra film layer is formed, which is disadvantageous in terms of running cost of materials and production tact.

  Furthermore, it is considered difficult to keep the difference between low damage and high damage within a desired range due to the inclination of the target (or magnetic circuit).

  The present invention solves the above-mentioned problems, and it is not necessary to change the pressure in the vacuum chamber or the input power to the electrodes during film formation, and minimizes damage to the organic thin film on the substrate. An object of the present invention is to provide a method for producing a transparent electrode of an organic EL element using a sputtering method having excellent practicality, which enables efficient film formation while limiting to the limit.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a shutter is disposed opposite to a target provided in a vacuum chamber, and a substrate is conveyed behind the shutter and to the side of the shutter. A first step of forming a film on the substrate, and a second step of moving the shutter to a position where the space facing the target is not blocked and forming the film on the substrate at a position facing the target. It is characterized by including.

  With such a configuration, by creating a step capable of forming a film near a relatively thin discharge space of plasma near the target side surface and a step capable of forming a film near a plasma dense discharge space near the target, Since it is possible to make a difference in the energy of recoil ions and γ-electrons, the situation of the film required when softly forming a film directly above the organic EL element and when the film formation speed is more important than damage It is possible to achieve film formation that matches the requirements. In addition, the discharge state is stable because it is controlled only by the position of the shutter and the substrate, rather than by controlling the damage due to high energy particles by changing the pressure or input power, or the distance between the target and the substrate, or even by a magnetic circuit. Thus, film formation is possible.

  According to a second aspect of the present invention, in the method for manufacturing a transparent electrode of an organic electroluminescent element according to the first aspect, the first step includes a step in which the substrate reciprocates a plurality of times between both sides of the shutter. Features.

  With such a configuration, it is possible to prevent light distribution from occurring in a film to be formed.

  According to a third aspect of the present invention, in the method for manufacturing a transparent electrode of an organic electroluminescent element according to the first aspect, the substrate is reciprocated in at least one of the first step and the second step. It is characterized in that film formation is performed.

  With such a configuration, it is possible to cancel the influence by orienting the film inclined in one direction with respect to the substrate by forming the film in the vicinity of the target side surface.

  According to a fourth aspect of the present invention, in the method for manufacturing a transparent electrode of an organic electroluminescent element according to the first aspect, the substrate transport mechanism is installed in a plurality of rows in the vertical direction at a position facing the target, and a plurality of transported In the substrate, the substrate on the target side functions as a shutter for the substrate on which film formation is started.

  With such a configuration, the film formation of the rear substrate with respect to the target is performed at the positions on both sides of the shutter, and the film formation of the front substrate with respect to the target is performed at a position facing the target. Since the film forming step can be performed simultaneously, the production tact time can be shortened and the utilization efficiency of the target can be improved.

  According to a fifth aspect of the present invention, in the method for producing a transparent electrode of an organic electroluminescent element according to the fourth aspect, the target-side substrate is a dummy substrate.

  Invention of Claim 6 is a manufacturing method of the transparent electrode of the organic electroluminescent element of any one of Claims 1-5. WHEREIN: The moving direction of a board | substrate is with respect to the line bank of the said organic electroluminescent element. It is characterized by being parallel.

  With such a configuration, target particles flying onto the substrate are not shielded by the line bank, and uniform film formation can be performed over the entire surface of the element.

  According to the present invention, it is not necessary to change the pressure in the vacuum chamber or the input power to the electrodes during film formation, and efficient film formation is possible while minimizing damage to the organic thin film on the substrate, A manufacturing method that is extremely practical and stable and suitable for mass production is realized.

Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 1 of this invention Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 1 of this invention Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 1 of this invention Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 1 of this invention Explanatory drawing about reduction of the influence of orientation in Embodiment 1 of the present invention Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 2 of this invention Explanatory drawing about the moving film-forming of the vertical vacuum apparatus which performs sputtering for describing Embodiment 2 of this invention Explanatory drawing when the present embodiment is carried out in the manufacture of a top emission type organic electroluminescence device Explanatory drawing of moving film formation in a vertical vacuum apparatus for performing conventional sputtering Explanatory drawing of moving film formation in a vertical vacuum apparatus for performing conventional sputtering

  Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIGS. 1A to 1D are explanatory views of moving film formation in a vertical vacuum apparatus that performs sputtering for explaining the first embodiment of the present invention. In the following description, members corresponding to those described in FIGS. 5A and 5B are denoted by the same reference numerals.

  After the inside of the vacuum chamber 1 is adjusted to a predetermined sputtering pressure by an evacuation system (not shown) attached to the vacuum chamber 1, power is applied from a power source (not shown) connected to the target electrode 2. As a result, discharge is started.

  By the discharge, target particles jump out of the target 8 on the target electrode 2 and adhere to the substrate 3 to start film formation. At the same time, recoil ions and γ electrons also jump out and collide with the substrate 3. .

  First, the shutter 5 is disposed at a position facing the target electrode 2 where the discharge for film formation is started and at a position where the plasma is dark and the area where the distance between the target and the substrate is short is shielded. A slight leak from both sides of the shutter 5 is performed (so that a film can be formed on the substrate).

  FIG. 1A shows a schematic arrangement of the target electrode 2, the substrate 3 and the shutter 5 before soft film formation. The target electrode 2 is positioned above the target electrode 2 (direction facing the surface of the target electrode 2, Between the shutter 5), the plasma 6 and the target particle scattering range 7 are widened. Prior to film formation, the substrate 3 stands by at a position outside the target particle scattering range 7 due to the shielding effect of the shutter 5 or the like.

  FIG. 1B shows a schematic arrangement of the target electrode 2, the substrate 3 and the shutter 5 during the soft film formation, and the arrangement of the target electrode 2 and the shutter 5 is not different from the standby arrangement. The substrate 3 moves parallel to the surface of the target electrode 2 at a certain distance from the target electrode 2. The film formation is performed by causing target particles that slightly leak from both sides of the shutter 5 to collide with the substrate 3 (first step).

  Next, when the film is formed in the above-described state, damage can be reduced, but since the film formation rate is very slow, when the film is formed to a thickness that does not damage the substrate (organic EL element) 3, high-energy particles are formed. Even if a large number of aircraft come in, the production rate is increased by increasing the film formation rate.

  FIG. 1C shows a schematic arrangement of the target electrode 2, the substrate 3 and the shutter 5 immediately after the soft film formation. After the soft film formation, the substrate transport mechanism 4 moves the substrate 3 to the rear side of the shutter 5. The target particle is shielded by moving to (position facing the target electrode 2).

  FIG. 1 (d) shows a schematic arrangement of the target electrode 2, the substrate 3 and the shutter 5 during high-rate film formation, and only the shutter 5 is retracted from the state of FIG. 1 (c). As a result, the discharge space facing the target electrode 2 extends below the substrate 3, and a large amount of target particles, recoil ions, and γ electrons collide with the substrate 3. Therefore, a large number of high-energy particles come in, but film formation can be performed at a high film formation rate (second step).

  In the first embodiment, the film is formed on both sides of the shutter 5. However, if the soft film formation is performed on only one of the left and right sides, the angle between the target electrode 2 and the substrate 3 becomes an acute angle. The orientation of the deposited film is made.

  Therefore, as shown in FIG. 2, in order to reduce the influence of the orientation, the substrate 3 is reciprocated from the right side of the shutter 5 to the left side, the left side, the right side, and so on with respect to the shutter 5 as indicated by the arrows in the figure. It is desirable to perform soft film formation to cancel the orientation.

(Embodiment 2)
FIGS. 3A and 3B are explanatory views of moving film formation of a vertical vacuum apparatus that performs sputtering for explaining the second embodiment of the present invention.

  The difference from the first embodiment is that the substrate transfer mechanisms 4 are arranged in a plurality of upper and lower rows (two rows are shown in the figure. The substrate transfer mechanisms 4 are arranged in parallel), and the substrates 3 can be transferred independently. Is a point. Moreover, each board | substrate conveyance mechanism 4 can move the board | substrate 3 to arbitrary positions and arbitrary timings, and there is no shutter 5 of Embodiment 1 instead.

  In this example, the substrate transport mechanism 4 is connected so as to be able to return the substrate 3 and sequentially transport the substrates 3.

  FIG. 3A shows a schematic arrangement of the target electrode 2, the substrate 3, and the substrate 3 ′ during the soft film formation on the first substrate, and the substrate transport mechanism 4 on the side far from the target electrode 2 has a substrate. 3, and before starting the soft film formation on the substrate 3, the first substrate 3 ′ is placed on the substrate transport mechanism 4 on the side close to the target electrode 2, and the first substrate 3 'Is disposed at a position facing the target electrode 2 so that the first substrate 3' has the function of the shutter 5 in the first embodiment (hereinafter, the first substrate 3 'is referred to as the shutter substrate 3'). ).

  The substrate 3 of the substrate transport mechanism 4 on the side far from the target electrode 2 is arranged beside the shutter substrate 3 'as in FIG. After the arrangement of both the substrates 3 and 3 ′ is determined by the two rows of substrate transport mechanisms 4, soft film formation is started.

  FIG. 3B shows a schematic arrangement of the target electrode 2, the substrate 3, and the shutter substrate 3 ′ during high-rate film formation on the substrate, and after the deposition of a predetermined film thickness on the substrate 3 is finished, 3 is conveyed downstream in the conveying direction (left side in the figure).

  On the other hand, the shutter substrate 3 ′ completes the role as a shutter for the substrate 3 at the same time as the high-rate film formation of the substrate 3 is finished, and is transported to the downstream side (right side in the figure) in the transport direction that is completely unrelated to the film formation. Is done. The deposited substrate 3 circulates in the transfer region, moves to the substrate transfer mechanism 4 on the side close to the target electrode 2, and is disposed at a position facing the target electrode 2.

  After that, although not shown in the figure, when the second substrate is formed, since it is necessary to perform soft film formation as described earlier, one piece is placed on the substrate transfer mechanism far from the target electrode. Place it next to the eye substrate. In this case, the first substrate mounted on the substrate transport mechanism on the side close to the target electrode functions as a shutter with respect to the second substrate, and the low damage film formation (second substrate) and the high rate are achieved. Film formation (first sheet) can be performed simultaneously. Thereafter, the film formation is repeated by this repetition.

  When starting the soft film formation for the first time, before the film formation, the substrate of the substrate transport mechanism 4 on the side close to the target electrode 2 is replaced with a dummy substrate and disposed at a position facing the target electrode 2. Accordingly, the dummy substrate may be provided with the function of the shutter 5 in the first embodiment.

  FIG. 4 is a perspective view for explaining a top emission type organic electroluminescent element.

  In FIG. 4, a reflective electrode 12 is patterned as a first electrode on a substrate 11, and a partition wall 13 that is a line bank is formed between the reflective electrodes 12.

  On the reflective electrode 12, a hole transport layer and an organic light emitting layer are provided in this order, and an electron injecting protective layer and a transparent electrode as a second electrode are further provided on the organic light emitting layer. And the board | substrate 11 provided with the reflective electrode 12, the partition 13, the positive hole transport layer, the organic light emitting layer, the electron injection property protective layer, and the transparent electrode is sealed with the barrier layer, the resin layer, and the sealing base material. .

  When the substrate 3 is moved and sputtered as in the embodiment shown in FIGS. 1 to 3, since the partition wall 13 may shield the sputtered particles, the transport direction of the substrate 11 is a direction parallel to the partition wall 6 ( (Arrow direction) is desirable.

  As described above, in the present embodiment, the arrangement of the target electrode 2 and the substrate 3 is unnecessary without controlling the gas pressure in the vacuum chamber 1 or the input power to the electrodes as in the prior art (in a state where these are kept constant). With the structure alone, in the initial stage of film formation, a soft film is formed so as not to damage the organic thin film at a low rate, and the organic thin film is covered with the initial film formed by the soft film formation. It is possible to form a film with a desired thickness in time (the organic film is protected by the initial film even if the film is formed at a high rate with great damage to the organic film).

  Since the present embodiment is configured as described above, it does not damage the organic thin film or the like when the film is deposited, that is, the film forming material that adheres immediately above the organic thin film or the like previously formed on the substrate 3. After the soft film formation, the high-rate film formation can be performed (the film formed softly on the organic thin film or the like does not cause the high-rate film formation material to directly collide with the organic thin film, etc. The organic thin film is protected), and good film formation can be performed in a short time. Of course, there is no need to change the gas pressure in the vacuum chamber or the input power to the electrode as in the prior art. The production tact time can be shortened by the amount of time required for voltage stabilization.

  Accordingly, an organic EL element is manufactured by forming a sealing film for sealing the light emitting portion on the light emitting portion formed by sequentially laminating the anode, the organic light emitting layer, and the cathode on the substrate as described above. In this case, a high-quality sealing film can be formed in a short time without damaging the light emitting portion, and the quality and productivity of the organic EL element can be improved.

  In particular, when forming a bottom emission type organic EL device formed by sequentially laminating an anode, an organic light emitting layer, a cathode, and a sealing film on a transparent substrate, a cathode or a sealing film ( Or a top emission type organic EL device formed by sequentially laminating an insulating layer, a metal anode, an organic light emitting layer, a metal auxiliary cathode, a transparent electrode, and a sealing film on a substrate. In this case, the metal thin film on the substrate is damaged by forming a metal auxiliary cathode, a transparent electrode or a sealing film (or at least two of these films) using the sputtering method of the present embodiment. A sputtered film can be efficiently formed while minimizing.

  Therefore, according to the present embodiment, it is not necessary to change the pressure in the vacuum chamber and the input power to the electrodes during the film formation, and it is possible to efficiently perform the process while minimizing the damage to the organic thin film on the substrate. It is extremely practical for enabling membranes.

  Note that the present invention is not limited to the configuration of the present embodiment, and the specific configuration of each component can be changed as appropriate according to specifications and the like.

  The present invention is applied to a manufacturing method for manufacturing a transparent electrode of an organic electroluminescent element by forming a transparent conductive film on a substrate in a sputtering method.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Target electrode 3, 3 'Substrate 4 Substrate conveyance mechanism 5 Shutter 6 Plasma 7 Target particle scattering range 8 Target 11 Substrate 12 Reflective electrode 13 Partition

Claims (6)

A first step of forming a film on the substrate by disposing a shutter facing a target provided in a vacuum chamber, transporting the substrate behind the shutter and to the side of the shutter, and
And a second step of moving the shutter to a position where the space facing the target is not blocked and performing film formation on the substrate at a position facing the target. Manufacturing method.   2. The method of manufacturing a transparent electrode of an organic electroluminescent device according to claim 1, wherein the first step includes a step of reciprocating the substrate a plurality of times between both sides of the shutter.   2. The transparent electrode of the organic electroluminescent element according to claim 1, wherein the film formation is performed while reciprocating the substrate in at least one of the first step and the second step. Production method.   The substrate transport mechanism is installed in a plurality of rows in a vertical direction at a position facing the target, and among the substrates to be transported, the substrate on the target side functions as the shutter for the substrate on which film formation is started. The method for producing a transparent electrode of an organic electroluminescent element according to claim 1.   The method for producing a transparent electrode of an organic electroluminescent element according to claim 4, wherein the substrate on the target side is a dummy substrate.   The method for producing a transparent electrode of an organic electroluminescent element according to any one of claims 1 to 5, wherein the moving direction of the substrate is parallel to the line bank of the organic electroluminescent element.

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