JP5218917B2 - Manufacturing method of organic EL panel - Google Patents

Description

  The present invention relates to a method for manufacturing an organic EL (electroluminescence) panel using a substrate with wiring.

  Conventionally, an organic EL panel including an organic EL element that is a self-luminous element formed of an organic material is, for example, a first electrode made of indium tin oxide (ITO) or the like serving as an anode, and an organic layer having at least a light emitting layer And a non-translucent second electrode made of aluminum (Al) or the like serving as a cathode are sequentially stacked to form the organic EL element (see, for example, Patent Document 1).

  Further, in the dot matrix type organic EL panel, a passive driving method is known as its driving method. In the passive drive organic EL panel, signal electrodes are formed in a plurality of lines on a substrate, and scanning electrodes are formed in a plurality of lines so as to intersect the signal electrodes. The intersection position is a light emitting pixel, and a plurality of the light emitting pixels are arranged to constitute a light emitting unit. In such an organic EL display, a line-sequentially scanned image is displayed on the display unit. Such a passively driven organic EL panel has the advantage that it is easier to manufacture than the active drive method.

  In recent years, dot matrix type organic EL panels have been required to be colored and high-definition. For this reason, it is necessary to reduce the resistance of the wiring portion. However, there is a limit to reducing the resistance of the ITO layer conventionally used for wiring materials. Therefore, by using a low resistance metal such as aluminum (Al) or Al alloy as an auxiliary wiring in combination with the ITO layer as used in thin film transistors (TFTs) and liquid crystal panels, the organic EL element circuit can be further reduced in resistance. It is known to be realized. However, although Al or the like has a low resistance, hillocks are likely to occur, and an Al oxide is easily formed on the surface, resulting in high contact resistance when electrically connected to another metal. Furthermore, for example, when a transparent conductor layer such as ITO and Al etc. are in direct electrical contact, Al and Al alloys are used as a single layer because Al and the transparent conductor layer have a high oxidation-reduction potential difference and are likely to corrode. There is inconvenience that we cannot do it.

  On the other hand, for example, Patent Document 2 discloses a method in which a cap layer made of molybdenum (Mo) or an Mo alloy is formed on an upper layer and a lower layer (between Al and ITO) of Al.

  In Patent Document 3, as a technique for reducing the contact resistance between the cathode and the auxiliary electrode, titanium nitride (TiN) or chromium (Cr) is used as an underlayer, Al or Al alloy is used as an upper layer, and the cathode and the lower electrode are used. A method of partially contacting the formation in direct contact is disclosed.

  Further, cited document 4 discloses an Al—Ni—B alloy in which nickel (Ni) and boron (B) are contained in Al as a technique that allows the cap layer to be omitted.

JP 59-194393 A JP 2001-311954 A JP 11-329750 A JP 2007-142356 A

  However, in the technique described in Patent Document 2, the laminate for reducing the resistance of the wiring has a three-layer structure, so that the manufacturing method becomes complicated, the manufacturing cost increases, and the productivity decreases. there were. Further, the technique described in Patent Document 3 has a problem that two photolithography processes are required to form the auxiliary wiring. Furthermore, using TiN as the underlayer requires dry etching for patterning, which causes a problem in productivity. When Cr is used for the underlayer, the contact resistance may be remarkably increased when left at a high temperature of about 100 ° C. even if the initial contact characteristics are good. In the technique described in Patent Document 4, the Al—Ni—B alloy is heated to, for example, 200 ° C. or higher after film formation in order to reduce the resistivity. However, in the manufacturing of a dot matrix type organic EL panel, an Al-Ni-B alloy after heat treatment is corroded in a chemical solution used in photoetching generally performed in an insulating film forming process for defining a light emitting pixel. There is a problem that the Al—Ni—B alloy cannot always be used in a single layer. In addition, even when a cap layer is formed on an Al—Ni—B alloy, there is a problem in that if the patterning is performed after the heat treatment, the chemical solution penetrates from the side surface, and the quality of the organic EL panel deteriorates and the yield decreases. there were.

  The present invention has been made in view of this problem. In an organic EL panel using a substrate with wiring, an organic EL panel that has low resistance and hardly generates hillocks, and that can improve quality and yield. The object is to provide a manufacturing method.

In order to solve the above problems, the present invention provides a first electrode formed on the substrate side on the substrate on which a wiring portion including a conductor layer containing aluminum, nickel, and boron is formed, and the first electrode a second electrode and an organic light emitting layer formed by sandwiching a light emitting portion opposed, patterned by photo-etching, an insulating film is formed to cover an end portion of at least the first electrode is patterned by photoetching , it forms a, and partition walls to be formed so as to separate the second electrode into a plurality of the wiring portion is the first, at least one electrically connected to become an organic EL panel of the second electrode In the manufacturing method, at least the wiring portion, the insulating film, and the partition are formed, and then the base is heated to perform a heat treatment for reducing the resistivity of the wiring portion.

  The wiring portion is formed by laminating a cap layer containing molybdenum or a molybdenum alloy on the conductor layer.

  Further, the wiring portion is formed by forming a transparent conductor layer between the base and the conductor layer.

  The wiring portion is a wiring for electrically connecting at least one of the first and second electrodes and a drive circuit.

  The present invention relates to an organic EL panel using a substrate with wiring, which is low in resistance and hardly generates hillocks, and can improve quality and yield.

The rear view of the organic electroluminescent panel in embodiment of this invention. The principal part enlarged view of the organic electroluminescent panel in embodiment same as the above. Sectional drawing which shows the organic electroluminescent panel in embodiment same as the above. The figure which shows the manufacturing process of the support substrate with wiring and organic electroluminescent panel of embodiment same as the above. The figure which shows the manufacturing method of the support substrate with wiring and organic electroluminescent panel of embodiment same as the above.

  Hereinafter, embodiments in which the present invention is applied to an organic EL panel will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing an organic EL panel. The organic EL panel includes a support substrate (base) 1, a light emitting region 2, a driver IC (drive circuit) 3, an anode wiring portion 4, and a cathode wiring portion 5.

  The support substrate 1 is an electrically insulating substrate with wiring made of a rectangular transparent glass material. On the support substrate 1, a light emitting region 2, a driver IC 3, an anode wiring part (wiring part) 4, and a cathode wiring part (wiring part) 5 are formed. Further, a sealing member that covers the light emitting region 2 in an airtight manner is disposed on the support substrate 1, but the sealing member is omitted in FIGS. 1 and 2.

  As shown in FIGS. 2 and 3, the light emitting region 2 includes a plurality of anodes (first electrodes) 6 formed in a line, an insulating film 7, a partition wall 8, a functional layer 9, and a plurality of lines. A cathode (second electrode) 10 to be formed is formed. That is, in the organic EL panel, each anode 6 and each cathode 10 intersect, and a plurality of light emitting portions (organic EL elements) each having a functional layer 9 sandwiched between the anode 6 and the cathode 10 are arranged in a dot matrix. It is what is done. The anode 6 and the cathode 10 are electrically connected to the driver IC 3 through the anode wiring part 4 and the cathode wiring part 5. In addition, each of the light emitting portions is airtightly covered with a sealing member 11 as shown in FIG.

  The driver IC 3 constitutes a drive circuit that drives the light emitting units in the light emitting region 2 and includes a signal line drive circuit, a scanning line drive circuit, and the like. The driver IC 3 is disposed on the support substrate 1 by COG (Chip On Glass) technology, and is electrically connected to each anode 6 and each cathode 10 through the anode wiring portion 4 and the cathode wiring portion 5.

  The anode wiring part 4 and the cathode wiring part 5 are members for electrically connecting the anode 6 and the cathode 10 and the driver IC 3 respectively. The anode wiring part 4 and the cathode wiring part 5 are made of an Al—Ni—B alloy containing a transparent conductor layer formed on the support substrate 1 and at least nickel (Ni) and boron (B) in aluminum (Al). And a cap layer made of molybdenum (Mo) or an Mo alloy are stacked from the support substrate 1 in this order. FIG. 3 shows a cathode wiring portion 5, which is formed by laminating a transparent conductor layer 5 a, a conductor layer 5 b, and a cap layer 5 c on a support substrate 1. Although not shown, the anode wiring portion 4 has the same laminated structure, and is formed by laminating a transparent conductor layer such as ITO, a conductor layer, and a cap layer extending from the anode 6.

  The transparent conductor layer 5 a is made of, for example, ITO, which is the same material as the anode 6, and is formed on the support substrate 1 in the same process as the anode 6.

The conductor layer 5b is made of an Al—Ni—B alloy, and is formed on the transparent conductor layer 5a of the support substrate 1 in order to reduce the resistance of the wiring. The Al—Ni—B alloy can be directly bonded to the transparent conductor layer 5a, and Ni forms an intermetallic compound with Al by heat treatment to provide bonding characteristics in the direct bonding of the conductor layer 5b to the transparent conductor layer 5a. Has the effect of improving. However, when the Ni content increases, the specific resistance of the wiring itself increases and becomes impractical. Conversely, when the Ni content is low, the amount of intermetallic compound produced with Al is reduced, and direct bonding with the transparent conductor layer 5a is not possible, and the heat resistance tends to decrease. B, like Ni, acts on heat resistance, but if its content increases, the specific resistance of the wiring itself increases and becomes impractical. Therefore, in the conductor layer 5b, when the Ni content is the atomic percentage Xat% of Ni and the B content is the atomic percentage Yat% of B,
Formula (1) 0.5 ≦ X ≦ 10.0
Formula (2) 0.05 ≦ Y ≦ 11.00
Formula (3) Y + 0.25X> 1.00
Formula (4) Y + 1.15X <= 11.50
It is desirable that each of the above formulas be satisfied and the balance be Al. Furthermore, it is preferable that the Ni content is 4.0 at% or more and the B content is 0.8 at% or less because the bonding reliability is improved. The conductor layer 5b preferably has a thickness of 100 to 500 nm so that sufficient conductivity and good patterning can be obtained.

  The cap layer 5c is made of Mo or Mo alloy, and is formed on the conductor layer 5b in order to protect the conductor layer 5b from corrosion. Examples of the Mo alloy include Ni-Mo, Mo-niobium (Nb), Mo-tantalum (Ta), Mo-vanadium (V), and Mo-tungsten (W). The cap layer 5c preferably has a thickness of 10 to 100 nm from the viewpoint of moisture resistance and patterning properties.

  The anode 6 is made of a transparent conductive material such as ITO, and after forming a layer of the transparent conductive material on the support substrate 1 by means such as vapor deposition or sputtering, a line shape is formed so as to be substantially parallel to each other by photoetching or the like. A plurality are formed. Further, the anode 6 is connected to the driver IC 3 through an anode wiring portion 4 extending from one side of the end portion (lower side in FIG. 1).

  The insulating film 7 is made of, for example, a polyimide-based electrically insulating material, and is formed on at least the end of the anode 6 so as to be positioned between the anode 6 and the cathode 10, thereby preventing a short circuit between the electrodes 6 and 10. In addition, it has an opening 7a that defines each light emitting portion of the light emitting region 2. The insulating film 7 is also extended between the cathode wiring part 5 and the cathode 10 and has a contact hole 7 b for connecting the cathode wiring part 5 and the cathode 10.

  The partition wall 8 is made of, for example, a phenol-based electrically insulating material and is formed on the insulating film 7. The partition wall 8 is formed by means such as photoetching so that the cross section thereof has a reverse taper shape with respect to the insulating film 7. A plurality of partition walls 8 are formed at equal intervals in a direction orthogonal to the anode 6. The partition wall 8 separates the functional layer 9 and the metal film into a plurality in a direction perpendicular to the anode 6 when a metal film to be the functional layer 9 and the cathode 10 is formed from above by a vapor deposition method or a sputtering method. is there.

  The functional layer 9 is formed on the anode 6 and has at least an organic light emitting layer. In this embodiment, the functional layer 9 is formed by sequentially laminating a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and an electron injection layer by means such as vapor deposition.

  For the cathode 10, a plurality of metallic conductive materials having higher conductivity than the anode 6 such as aluminum (Al) and magnesium silver (Mg: Ag) are formed in a line shape so as to intersect the anode 6 by means such as vapor deposition. It will be. The cathode 10 is formed by separating the metal film formed of the conductive material into a plurality by the partition walls 8. The cathode 10 is connected to the cathode wiring portion 5 through a contact hole 7 b provided in the insulating film 7, and is electrically connected to the driver IC 3 through the cathode wiring portion 5.

  The sealing member 11 is a flat plate member made of, for example, a glass material, and includes a concave portion 11a that houses each light emitting portion of the light emitting region 2 and a joint portion 11b that is formed so as to surround the entire circumference of the concave portion 11a. And disposed on the support substrate 1 via an adhesive 11c.

  The organic EL panel is configured by the above-described units.

  Next, an example of a method for manufacturing an organic EL panel using the support substrate with wiring 1 and the support substrate 1 will be described with reference to FIGS.

  First, in the anode etc. forming step S1, a transparent conductive material such as ITO is formed on the support substrate 1 in a layer thickness of 150 nm on the support substrate 1 by means such as sputtering, and then patterned by photoetching or the like to make the anode wiring portion 4 transparent. The conductor layer, the transparent conductor layer 5a of the cathode wiring part 5 and the anode 6 are formed (see FIG. 5A).

  Next, in wiring part formation process S2, it sputter | spatters in the inert gas atmosphere on the support substrate 1 using an Al-Ni-B alloy target, and forms into a film with a film thickness of 410 nm, and also using Mo alloy type target Mo or Mo alloy is sputtered to form a film with a thickness of 20 nm. The resistivity of the laminate immediately after sputtering is as high as about 10 μΩ / cm. Thereafter, patterning is performed by photoetching to form a conductor layer and a cap layer of the anode wiring portion 4, and a conductor layer 5b and a cap layer 5c of the cathode wiring portion 5 (see FIG. 5B). Thereby, the support substrate 1 with wiring which has the anode wiring part 4 and the cathode wiring part 5 as wiring is obtained. Mo or Mo alloy can be etched at approximately the same rate with the same etching solution (acidic aqueous solution) as Al-Ni-B alloy. Therefore, by using Mo or Mo alloy for the cap layer and cap layer 5c, the conductor layer and conductor layer 5b and the cap layer and cap layer 5c can be patterned in a lump. At this time, the temperature used in photolithography is set to 100 ° C. or less, so that the anode wiring portion 4 and the cathode wiring portion 5 maintain the composition and structure immediately after sputtering.

  Next, in an insulating film forming step S3, an electrically insulating material is applied on the support substrate 1, and then patterned by photoetching to form an insulating film 7 having an opening 7a and a contact hole 7b in the light emitting region 2 (see FIG. (Refer FIG.5 (c)).

  Next, in the partition formation step S4, an electrically insulating material is applied on the support substrate 1, and then patterned by photoetching to form the partition 8 perpendicular to the anode 6 on the insulating film 7.

  Next, in the heat treatment step S5, the conductor layer and the conductor layer 5b are activated, and the support substrate 1 is heated to perform a heat treatment in order to lower the resistivity to a desired value. The heating temperature in the heat treatment step S4 does not cause thermal damage to the insulating film 7 and the partition wall 8, and can reduce the resistivity of the conductor layer of the anode wiring part 4 and the conductor layer 5b of the cathode wiring part 5. Requires temperature. In this embodiment, the support substrate 1 was heated at 250 ° C. for 30 minutes. Further, depending on the material of the insulating film 7 and the partition wall 8, it is possible to heat at a temperature from 250 ° C. to 400 ° C. The heating time is 30 minutes, which is the time when the resistivity of the conductor layer and the conductor layer 5b decreases and saturates, but the heating may be performed for a longer time.

  Then, the functional layer 9 is laminated and formed so as to correspond to the anode 6 in the functional layer forming step S6, and the cathode 10 is laminated and formed on the functional layer 9 in the cathode forming step S7. Obtained (see FIG. 5D).

  And in sealing process S8, the sealing member 11 which has the recessed part 11a which covers the light emission area | region 2 is prepared, and it arrange | positions and fixes on the support substrate 1 via the ultraviolet curable adhesive 11c (FIG.5 (d)). reference). It is desirable that a moisture absorbent (not shown) that adsorbs moisture is disposed on the surface of the recess 11a facing the light emitting units. The organic EL panel having the light emitting region 2 is obtained by the above manufacturing process.

  In the organic EL panel using the support substrate 1 which is such a substrate with wiring, by forming the conductor layer and the conductor layer 5b made of an Al—Ni—B alloy, hillocks are hardly generated with low resistance. Since it can be directly bonded to the transparent conductor layer and the transparent conductor layer 5a, it is possible to obtain a wiring structure having excellent productivity without using a lower cap layer. Moreover, by forming the cap layer and the cap layer 5c made of Mo or Mo alloy on the conductor layer and the conductor layer 5b, corrosion of the conductor layer and the conductor layer 5b is prevented, and moisture resistance and heat resistance are improved. In addition, since the conductor layer and the conductor layer 5b can be patterned together, it is possible to obtain a wiring structure with excellent patterning performance.

  Furthermore, it was confirmed that the passive matrix type organic EL panel to which the present manufacturing process was applied was free from defects and improved in quality and yield. Conventionally, the deterioration of the quality and yield of the organic EL panel is caused by corrosion caused by contact of a chemical solution used for photoetching of an insulating film and a partition wall with a conductive layer in a state where an intermetallic compound is formed by heat treatment. It seems to be caused by scattering on the panel. The inventor of the present application pays attention to this point, and in the manufacturing process of the organic EL panel, after the insulating film 7 and the partition wall 8 are formed, the conductor layer and the conductor layer 5b are subjected to heat treatment for reducing the resistivity. It has been found that the deterioration of quality and yield can be suppressed without corroding the conductor layer 5b.

  In the present embodiment, the cathode wiring portion 5 is composed of a laminate of the transparent conductor layer 5a, the conductor layer 5b, and the cap layer 5c, and the anode wiring portion 4 is also composed of the same laminated structure. In the present invention, the wiring portion only needs to include at least a conductor layer made of an Al-Ni-B alloy, and the transparent conductor layer is not formed, but the conductor layer is formed directly on the substrate. A configuration in which the cap layer is not formed may be used.

  The present invention relates to a method for manufacturing an organic EL panel, and more particularly to a method for manufacturing an organic EL panel using a substrate with wiring.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Light emission area 3 Driver IC
DESCRIPTION OF SYMBOLS 4 Anode wiring part 5 Cathode wiring part 5a Transparent conductor layer 5b Conductive layer 5c Cap layer 6 Anode 7 Insulating film 7a Contact hole 8 Partition 9 Organic layer 10 Cathode 11 Sealing member

Claims (4)

An organic light emitting layer is formed by a first electrode formed on the substrate side and a second electrode facing the first electrode on a substrate on which a wiring portion including a conductor layer containing aluminum, nickel, and boron is formed. and sandwiching and formed by the light emitting portion, is patterned by photo-etching, an insulating film is formed to cover an end portion of at least the first electrode is patterned by photoetching to separate the second electrode into a plurality And the wiring portion is electrically connected to at least one of the first and second electrodes, and is a method of manufacturing an organic EL panel,
A method of manufacturing an organic EL panel, comprising: after forming at least the wiring portion, the insulating film, and the partition wall, performing a heat treatment for heating the base to lower the resistivity of the wiring portion. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is formed by laminating a cap layer containing molybdenum or a molybdenum alloy on the conductor layer. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is formed by forming a transparent conductor layer between the base and the conductor layer. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is a wiring for electrically connecting at least one of the first and second electrodes and a drive circuit.

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