TW201513427A - Hydrophobic bank - Google Patents

Abstract

A method of fabricating an electronic device having an electrically insulating bank structure having a side wall defining a well, the method comprising: forming the bank structure such that the side wall comprises a first slope extending from a surface layer region and a second steeper slope extending from the first slope, the side wall having a surface energy discontinuity at a point on the second slope spaced from the first slope; forming a layer structure having at least one layer comprising organic semiconductive material by depositing a solution of said material in the well, wherein the deposited solution wets the first and second slopes up to a pinning point at the surface energy discontinuity; and drying the deposited solution.

Description

Hydrophobic dike

The present invention generally relates to a method of fabricating an electronic device including a substrate having a surface layer and a bank structure defining the well on the surface layer, and a bank structure having a surface layer and a defined well on the surface layer Electronic device for the substrate.

A method involving the deposition of an active component (solution treatment) from a solution for manufacturing an electronic device has been extensively studied. If the active component is deposited from a solution, the active components are preferably contained in a desired region of the substrate. This can be achieved by providing a substrate comprising a patterned bank layer defining a well in which the active component can be deposited from solution. The wells contain the solution as it dries to maintain the active component in the zone of the substrate defined by the wells.

These methods have been found to be particularly useful for depositing organic materials from solution. The organic materials may be electrically conductive, semi-conductive, and/or photo-active such that they emit light when current is passed or by detecting current when light is applied thereto. Devices that utilize such materials are referred to as organic electronic devices. If the organic material is a luminescent material, the device is referred to as an organic light-emitting device (OLED). In addition, solution processing allows low cost, low temperature fabrication of thin film transistors (TFTs) and, in particular, organic thin film transistors (OTFTs). In such devices, it is particularly desirable to include an organic semiconductor (OSC) in a suitable region and in particular in the channel of the device, and a bank defining the well to contain the OSC may be provided.

Some devices may require more than a single solution deposited layer. A typical OLED (such as used in a display) can have two layers of organic semiconductor material, one of which can be A layer of luminescent material such as a light emitting polymer (LEP), and the other may be a layer of a hole transporting material such as a polythiophene derivative or a polyaniline derivative.

An advantageous simple bank structure has a single material/layer that is designed to contain all of these deposited liquids. However, for devices having a single bank material for all deposited liquids and a single pinning point, there is an electrical leakage path or short circuit risk between the electrodes on either side of the solution deposited layer. For example, in an OLED structure including an anode-HIL-IL-EL-cathode structure, leakage current can flow between the anode and the cathode via a leakage path on the boundary of the HIL. Similarly, the leakage path may be caused by direct contact of the cathode with a hole injection layer (HIL) on the bank, a very thin stack of devices on the bank, or point contact at the pinning point. The JV (current density-voltage) curve through the full printing device can, for example, exhibit high leakage (high current) when driven in reverse and/or before being turned on. In the case of a spin-coated intermediate layer (IL) and an electroluminescent layer (EL), the leakage is much lower because the HIL is completely covered by the spin-coated film on top. Can result in much lower efficiency.

Currently, low leakage devices typically require a dual bank system to separate the anode pinning point from the cathode. However, a single bank can reduce complexity compared to a double bank structure. Alternatively or in addition, a single bank patterned by photolithography can provide an inexpensive method for pixel (deck) definition. However, this bank may expose the anode region to hydrocarbons (resist residues) and/or provide a single fluid pinning point for all solution treated layers (HIL, IL and EL). It has been shown that the short path length between the highly conductive HIL plus the anode (ITO) surface and the HIL-IL-EL-cathode coincident pinning point will result in a high leakage device.

Similarly, a light-emitting device having a bank structure can have poor color uniformity and/or luminous efficiency across the active area.

Accordingly, it is desirable to provide an improved structure that allows different liquids to be contained within the well and/or a process for making the structure. The improved structure may have advantages such as any one or more of the following: in particular, improved color uniformity across the device, lower and/or tunable electrical leakage, increased interaction across the device Total power efficiency and / or efficiency Rate uniformity, (eg, OLED emission) improved service life stability (preferably, for example, more stable and/or more repeatable device illumination during life testing), more compact devices, and The ability to reduce structural complexity and/or make through fewer processing steps (either of which can result in improved time or cost efficiency of device fabrication, improved device yield, repeatability, can (for example) The reduced cost requirement for the volume and/or number of constituent materials).

Reference is made to the following disclosure for use in understanding the present invention: - US 8,063,551 (Du Pont); - US 2006/197086 (Samsung Electronics Co Ltd.); - US2010/271353 (Sony Corporation (Sony Corp));- WO2009042792 (inventor Tsai Yaw-Ming A et al.); - US2007/085475 (Semiconductor Energy Lab); - US7799407 (Seiko Epson Corp); US7604864 (Dainippon Screen MFG); - WO9948339 (Seiko Epson Corporation); - JP2007095425A (Seiko Epson Corporation); - WO 2009/077738 (PCT/GB2008/004135, on June 25, 2009 The inventors are Burroughes and Dowling); and - WO2011/070316 A2 (PCT/GB2010/002235, published on June 16, 2011, the inventors are Crankshaw and Dowling).

The present invention relates to a method of fabricating an electronic device having an electrically insulating bank structure including a sidewall defining a well, the method comprising: forming the bank structure such that the sidewall includes a first slope extending from the surface layer region and The second bevel extends the second steeper slope a surface energy discontinuity at a point spaced apart from the first slope on the second slope; forming at least one of the materials by depositing a solution of the organic semiconducting material in the well a layer structure of the layer, wherein the deposited solution wets the first slope and the second slope until a pinning point at the surface energy discontinuity; and drying the deposited solution.

According to a first aspect of the present invention, there is provided a method of fabricating an electronic device comprising a substrate having a surface layer and a bank structure defining a well on the surface layer, the bank structure comprising an electrically insulating material and having an area surrounding the surface layer One region thereby defining a sidewall of the well, the surface layer region including a first electrode, and the device further includes a second electrode and a semiconducting material disposed between the first electrode and the second electrode, The method includes forming the bank structure having the sidewall including a first slope extending from the surface layer region and a second slope extending from the first slope, wherein the second slope is steeper than the first slope, wherein the The sidewall has a surface energy discontinuity at a point spaced apart from the first slope on the second slope; forming a layer structure having at least one layer disposed between the first electrode and the second electrode And having the semiconductive material, wherein the forming the layer structure comprises: depositing an organic solution on the surface layer region and the first slope surface and the second slope surface of the sidewall to form This layer of processing liquid, wherein the organic solution was deposited wets the first inclined surface and the second inclined surface until the staple of the discontinuity of the surface energy of tie points; and drying the deposited organic solution.

Thus, embodiments may provide a pinning point for at least one solution processable layer (preferably, a plurality of solution processable layers are all pinned at the same point) such that the pinning point is by virtue of its The paths having different slopes and deviating from the straight line are separated from the surface layer regions. This can reduce the risk of a leakage path or short circuit between the electrodes (eg, the anode and cathode) on either side of the solution deposition layer. For example, in an OLED structure comprising an anode-HIL-IL-EL-cathode structure, any leakage path between the anode and the cathode along the boundary of the preferably high resistance HIL is extended. The extended path preferably has a sufficiently high resistance Force to prevent leakage that would otherwise significantly degrade, for example, efficiency, reliability, and/or service life, color variations, and the like.

More specifically, the resulting device structure is contemplated, and it should be noted that the surface is preferably formed by a process step that results in a boundary between a wet (e.g., hydrophilic) region and an unwetted (e.g., hydrophobic) region. Energy discontinuity. This boundary is preferably at the top of the second bevel. The top of the second bevel is preferably adjacent to a relatively flat surface of the bank structure, the flat surface being opposite and parallel to the surface layer. In any event, the surface energy discontinuity is preferably remote from the first bevel and thus away from the surface layer region.

The method can include depositing at least another solution (eg, an EL (light emitting layer) and/or an IL (intermediate layer)) over the solution processable layer, wherein the at least one other solution wets up to the pinning point; Drying the deposited at least one other solution. Thus, a plurality of such solution processable layers can have the same pinning point.

The method may further be provided, wherein the forming the bank structure comprises: forming a first bank layer comprising a photoresist on the surface layer of the substrate; photo patterning and developing the first bank layer to expose the surface a region of the layer; depositing a fluorinated photoresist solution onto the first bank layer and the exposed regions of the surface layer to form a second bank layer; baking to harden the second bank layer a fluorine-containing compound of the fluorinated photoresist solution migrates to a surface of the second bank layer during the baking to increase a contact angle of the organic solution with the surface; and photopatterning and developing the second bank a portion to re-expose the region of the surface layer and expose the region of the first bank layer such that the first bank layer region has the first slope and the second bank layer has the second slope, wherein The contact angle is increased above a contact angle of the organic solution with the first slope and the second slope, and the pinning point is at a boundary of the surface of the second bank layer having the migrated fluorine-containing compound. The surface to which the compounds migrate to during baking can generally be referred to as a "free surface", that is, interfaced with an external environment (e.g., air). As in any embodiment using such a fluorinated photoresist, the photoresist may be supplied by fluorination by a photoresist manufacturer, or the process may have the addition of a fluorochemical to the non-fluorinated compound. An additional step of the photoresist. In any event, after the second bank layer has hardened, the second bank layer preferably includes a higher concentration of fluorochemical than the first bank layer. Further, after the second bank layer has been developed to remove portions of the second bank layer, a portion of the portion of the previous "free surface" preferably has the second bank exposed by the removal The wet/non-wet boundary of the edge of the layer, which is part of the sidewall. Therefore, in addition to the double inclined side walls, pinning points can also be formed.

The method may further be provided, wherein the forming the bank structure may include: forming a bank structure layer by depositing a fluorinated photoresist solution on the surface layer, and drying the deposited solution to make the bank structure layer Hardening, wherein the fluorine-containing compound of the fluorinated photoresist solution migrates to the surface of the bank structure layer during the baking to increase the contact angle of the organic solution with the surface; depositing on the bank structure layer and Drying the photoresist layer and photo patterning and developing the photoresist layer; a dry etching step for etching the bank structure layer through the developed photoresist layer to expose the surface layer region, such that the Etching the bank structure layer having the sidewall surrounding the exposed surface layer region and including the first slope and the second slope; and removing the developed photoresist layer to expose the surface of the bank structure layer, the The exposed surface includes the migrated fluorine-containing compound, wherein the surface energy discontinuity is at an interface between the exposed surface comprising the migrated fluorine-containing compound and the etched sidewall. The dry etching step can include reactive ion etching, preferably using an oxygen plasma. Similarly to the above, the portion of the portion of the "free surface" that was previously the layer of the bank layer preferably has a wetting with the edge of the bank layer of the developed exposure by removing portions of the bank layer. The border is not wetted and this edge is part of the sidewall. Therefore, in addition to the double inclined side walls, pinning points can also be formed.

Still further provided, the method of forming the bank structure can include: developing and photo patterning the bank structure layer to expose the surface layer region surrounded by sidewalls of the bank structure layer, wherein the bank portion is Depositing the photoresist layer on the structural layer includes depositing a photoresist solution on the photopatterned bank structure layer, and developing the photoresist layer includes re-exposure The surface layer region, and the dry etching step for exposing the surface layer region, extends the exposed region by thinning the bank structure layer to thereby form the first slope and the second slope.

The method may further be provided wherein: the photo patterning the photoresist layer may comprise passing through a substantially non-transmissive region, a partially transmissive region, and a substantially fully transmissive region (at least having a greater transmissive region than the portion) a mask of the transmittance) radiates the photoresist layer; and the developing the photoresist layer includes a region where the photoresist is completely removed and partially removes the photoresist exposed to the radiation through the portion of the transmissive region region.

The method may further be further provided, wherein the forming the bank structure comprises: forming a bank layer by depositing a fluorinated photoresist solution on the surface layer; baking to harden the bank layer, wherein The fluorine compound of the photoresist solution migrates to the surface of the bank layer during the baking to thereby increase the contact angle of the organic solution with the surface; the light patterning the hardened bank layer, the light patterning includes The first radiation dose radiates a first region of the bank layer and the second region of the bank layer is irradiated with a second radiation dose, the second radiation dose being less than the first radiation dose; developing the bank layer to expose the surface The region of the layer and partially removing the region of the bank layer that is irradiated by the second radiation dose, the portion being removed thereby providing a sidewall having a first bevel and a second bevel surrounding the exposed region, wherein The pinning point is at the boundary between the surface of the bank layer having the migrated fluorine-containing compound and the sidewall. The first region may be above the surface region or over a portion of the bank structure that will remain, depending on whether a negative photoresist or a positive photoresist is used. The portion removes preferably thinning the region of the bank layer extending to a region of the surface layer to give a longer edge along the sidewall and thus along the edge of the solutionable layer to be deposited in the well The bracket structure of the path length.

The method may further be provided wherein: the patterning of light comprises simultaneously radiating the bank layer through the first mask and the second mask, wherein the radiating the first region at the first dose comprises passing through the first mask The cover and the fully transmissive region of the second mask radiate the first region, And radiating the second region at the second dose includes radiating the second region through at least a portion of the transmissive region of each of the first mask and the second mask. The at least partially transmissive region can include a fully transmissive region of the first mask and/or a partially transmissive region of the second mask. At least one of the regions is preferably a partially transmissive region having a transmission gradient.

The method can further be provided wherein: the photo patterning comprises irradiating the bank layer through a mask having a partially transmissive region and a more (preferably, fully) transmissive region, wherein the first dose is irradiated The first region includes radiating the first region through the more transmissive region, and the radiating the second region at the second dose includes radiating the second region through the partially transmissive region.

Still further provided, the method comprising: depositing a reflector layer on a region of the surface layer, wherein: depositing the fluorinated photoresist solution deposits the fluorinated solution on the reflector layer and the surface layer; Photo patterning includes radiating the bank layer through a mask, wherein the radiating the first region includes the first region absorbing a portion of the first dose received directly through the mask and absorbing from the first mask And reflecting back to one of the doses in the first region by the reflector layer.

The method may further be provided, wherein the electronic device is an optoelectronic device, such as a light emitting device or a light absorbing device, preferably a light absorbing device such as an organic photovoltaic device (OPV; for example, a solar cell) or such as an organic light emitting diode (OLED) ) illuminating device. Alternatively, the device is a thin film transistor.

The method may further be further provided, wherein the electronic device is an organic light emitting diode and the organic solution is used to provide a hole injection layer (HIL). Additionally, at least another solution processable layer may be formed on the solution processable layer and between the first electrode and the second electrode, the (or other) solution processable layer being used to separately provide an intermediate layer ( IL) and/or luminescent layer (EL).

The method may further be provided, wherein the organic solution is deposited on the first slope and The contact angle is 10° or less from the first bevel extending to at least one of the second bevel regions of the pinning point. This contact angle generally allows for good wetting of the surface.

The method may further be provided wherein the organic solution has a contact angle of 50 or more when deposited on an area of the bank structure extending away from the first slope from the pinning point. This contact angle generally does not allow for good wetting of the surface, i.e., no wetting.

According to a second aspect of the present invention, there is provided an electronic device comprising a substrate having a surface layer and a bank structure defining the well on the surface layer, the bank structure comprising an electrically insulating material and having one of the surface layers surrounding The region thereby defining a sidewall of the well, the surface layer region comprising a first electrode, and the device further comprising a second electrode and a semiconducting material disposed between the first electrode and the second electrode, wherein: The sidewall has a first bevel extending from the surface layer region and a second bevel extending from the first bevel, wherein the second bevel is steeper than the first bevel; and the device comprises a layer structure having at least one layer, at least one The layer is a solution-processable layer having the semi-conductive material and disposed between the first electrode and the second electrode, wherein: at least one of the solution-processable layers has the second slope and the a pinning point at a point at which the first bevel is spaced apart, the solution treatable layer being disposed on the surface layer region and the first bevel and the second bevel of the sidewall.

Thus, and similarly to the first aspect, embodiments may provide a pinning point for (several) solution-processable layers that are offset from the line by having different slopes along their entire length Separated from the surface layer area. This in turn reduces the risk of a leakage path or short circuit between the electrodes (e.g., anode and cathode) on either side of the solution deposition layer. For example, any leakage path between the anode and the cathode along the boundary of the preferred high resistance HIL of the OLED is preferably extended to have a sufficiently high resistance to prevent leakage which would otherwise For example, efficiency, reliability, and/or service life, color variations, and the like are significantly degraded.

More specifically, the device structure is contemplated, it being noted that the surface layer can include one of an electrode (eg, an anode) and/or a partially reflective layer. For the bottom emitter embodiment, the table The top layer (e.g., tin oxide, such as indium tin oxide (ITO)) and the substrate (glass) are preferably at least partially transparent. A separate sub-layer (e.g., a silver layer) of the surface layer can provide a partially reflective layer as described above, the partially reflective layer can be configured to form a size that is sufficiently small to allow for narrower illumination from the illumination device The optical cavity of the visible quantum effect of the emission spectrum, or specifically the microcavity. For devices comprising such (eg, Ag) reflective layers, the fabrication of the device can include: blanket Ag (alloy) deposition; blanket ITO deposition; patterning ITO to form at least one electrode; And then the bank is patterned. Alternatively, the electrode layer of the surface layer can further function as a partially reflective layer.

The electronic device may be further provided, wherein a solution for forming the solution-processable layer disposed on the surface layer region is deposited on the first slope and from the first slope to the second slope of the pinned region In at least one of the solutions, the contact angle of the solution is 10 or less. Additionally or alternatively, when a solution for forming the solution processable layer disposed on the surface layer region is deposited on a surface region of the bank structure extending from the pinning point away from the first slope surface, The contact angle of the solution is 50 or more. Therefore, this solution may have a contact angle of both 10° or less and 50° or more.

The electronic device can be further provided, wherein the bank structure includes at least one photoresist layer.

The electronic device can be further provided, wherein the photoresist layer has the point on the second slope and includes a fluorine-containing compound.

The electronic device can be further provided, wherein the bank structure includes a plurality of photoresist layers, the photoresist layer having the first slope.

The electronic device can be further provided, wherein the bank structure includes the photoresist layer having a fluorine-containing compound and the first slope and the second slope.

The electronic device can be further provided wherein the first bevel has a bevel angle of less than or equal to 20 degrees (more preferably, less than 5 degrees, 10 degrees, or 15 degrees) relative to the surface layer. The angle may be along the first slope and/or in particular at the first slope The average of the cases.

The electronic device may be further provided, wherein the first slope extends to a thickness of a bank structure of less than 300 nm, preferably less than 200 nm at a boundary with the second slope (wherein the height difference of the thickness relative to the surface layer), Preferably, at least one of the first slope and the second slope extends along a thickness of the bank structure of 100 nm to 150 nm (thus, the height traversed by the first slope and/or the second slope is preferably The ground is in the range of 100 nm to 150 nm; in the case where the bank structure is formed in a plurality of layers and has respective slopes, at least one, for example, the first slope preferably traverses a height of 100 nm to 150 nm).

The electronic device can still be further provided wherein the sidewall extends from the surface region to provide a bank structure thickness of at least 300 nm, preferably at least 1 μm. Therefore, the maximum height of the side wall above the surface layer is preferably at least 300 nm. In an embodiment, the maximum height is advantageously sufficiently thick to withstand a dry etching step, such as RIE.

Still further provided, the electronic device, wherein the first slope extends along the surface layer for a length of at least 1 μm, preferably wherein the second slope extends along the surface layer for a length of at least 8 μm, preferably Wherein the sidewall (at least the first bevel and the second bevel) extends across the surface layer for a length of at least 10 μm.

The electronic device can be further provided, wherein the device is a light emitting device, and wherein the solution processable layer comprises an organic semiconducting material for providing a hole injection layer (HIL), preferably wherein the light emitting device is an OLED. Additionally, at least one of the solution processable layers can include another organic semiconducting material disposed over the material for providing the HIL, wherein the other organic semiconducting material is used to provide an intermediate layer (IL) or Light-emitting layer (EL).

When the electronic device is a light emitting device such as an OLED, preferably one of the first electrode layer and the second electrode layer (either one of the first electrode layer or the second electrode layer; Preferably, if the bank emitter device is a second electrode layer, it is light transmissive (if the cell emitter device is used, preferably the substrate is also transmissive). The device preferably includes being disposed (eg, between (preferably, a glass) substrate and the first electrode layer) A portion of the light reflective (preferably complete) layer of the microcavity having the reflective electrode layer is formed (preferably metallic, such as silver, and/or preferably blanket deposited rather than patterned). This cavity may allow for amplification of the light and/or making the device more efficient.

The preferred embodiment is defined in the accompanying independent technical solution.

Any one or more of the above aspects of the preferred embodiment and/or any of the above selected features may be combined in any permutation manner.

11‧‧‧ surface layer

12‧‧‧deck structural layer

13‧‧‧Surface area

14‧‧‧ photoresist layer

15‧‧‧ surface

21‧‧‧ surface layer

22‧‧‧deck structural layer

23‧‧‧Surface area

24‧‧‧ photoresist layer

25‧‧‧ Surface

31‧‧‧ surface layer

32‧‧‧First dike layer

33‧‧‧Surface area

34‧‧‧ surface

41‧‧‧ surface layer

42‧‧‧deck layer

43‧‧‧Surface area

44‧‧‧Area

45‧‧‧ surface

51‧‧‧ surface layer

52‧‧‧deck layer

53‧‧‧Surface area

54‧‧‧Area

55‧‧‧ Surface

61‧‧‧ surface layer

62‧‧‧deck layer

63‧‧‧Surface area

64‧‧‧Area

65‧‧‧ surface

L1‧‧‧Solid-treated layer/layer

L2‧‧‧ Another solutionable layer/layer

S1‧‧‧First bevel/bevel

S2‧‧‧Second slope/bevel

For a better understanding of the present invention and how the invention may be practiced, reference will now be made to the accompanying drawings, in which FIG. 1a shows an exemplary fabrication method in which a fluorinated bank material is spin coated to an anode (eg, , ITO), and photopatterning to provide a well; Figure 1b shows the use of a single masking step for a portion of the transmissive region of the mask to define a long anode to cathode distance; Figure 1c shows a RIE with a short sidewall path length Patterning bank pixels (upper to middle) and, conversely, embodiments providing pixels of longer path length (lowermost pattern) according to an embodiment; Figure 1d shows a process formed from Figure 1a or Figure 1b Figure 2 shows a graph of service life (device stability); Figure 3a shows a dual development process; Figure 3b shows a double mask process using a single patterned layer; Figure 3c shows a single mask using a single patterned layer Cover portion transmissive process; Figure 3d shows a single mask process using a single patterned layer using a reflective region and a secondary exposure dose; Figures 4a through 4e show scanning power for a stent bank profile of the embodiment Microscopic image; FIG. 5 shows the variation across the active region of the device and the thickness of the HIL + IL emission CIE values; FIG. 6 illustrates the structure of the boundary of the steep portion of the bank to be eliminated; and Figure 7 shows a histogram of the thickness measurement of the HIL region for a standard bank embodiment and a shallow bank embodiment.

In general, the layers of an exemplary OLED embodiment can be as follows:

A germanium substrate, such as glass, preferably having a surface layer comprising an ITO (80 nm) electrode and optionally a reflective layer (eg, Ag) for forming a microcavity

̇HIL (hole injection layer) = inkjet printing using ND3202b from Nissan Chemical Industries

̇IL (middle layer)

̇EL (Light Emitting Layer) comprising a light emitting polymer LEP, such as a green light emitting polymer.

Embodiments typically provide, for example, a single bank configuration with a longer path length to thereby reduce leakage current. For OLEDs, this path length can be between the anode surface (eg, ITO) and the HIL-IL-EL coincident fluid pinning point. These longer path lengths beside the high resistance HIL can form a high resistance path for any potential parasitic leakage current and/or non-emissive edge device diode. This bank structure has proven an improvement in the service life stability of OLEDs.

Several bank processes for this embodiment are contemplated in the following description. For example: (i) developed hydrophobic bank via secondary layer patterning and partial reactive ion etching (RIE); (ii) unpatterned hydrophobic with partially exposed pixel edges due to RIE masking layer a dike portion; (iii) a dual development process; (iv) a double mask process using a single patterned layer; (v) a single mask partial transmission (leakage) process using a single patterned layer; and (vi) utilization A single masking process using a single patterned layer for the reflective region and the secondary exposure dose.

An example of such a process can provide a single developed hydrophobic bank having a partially oxygen plasma etched cradle. Advantageously, a single developed hydrophobic bank and subsequent patterning steps Oxygen plasma is allowed to purge the ITO region and also partially etch a predefined amount of bank. The ITO and the partially etched bank are preferably hydrophilic, allowing the HIL to wet up to the unetched regions of the hydrophobic bank. The section of HIL has a bank below the HIL pinning point that will share this pinning point with IL and EL. The active anode is advantageously separated from the cathode for a long and preferably device designed distance, thus causing, for example, lower current leakage when using a high resistance HIL.

A single bank configuration for the OLED can thus be improved by providing a wetted anode surface (ITO) and a longer path length between the anode surface and the HIL-IL-EL coincident fluid pinning point. These longer path lengths can form a high resistance option for any potential parasitic leakage current. Embodiments allow the anode-to-cathode path to be extended in a controlled manner and thus tunable to reduce parasitic leakage current, which in turn can improve device efficiency.

Alternatively or in addition, such processes may reduce the structural complexity relative to the dual bank construction.

Figure 1a shows an exemplary fabrication process in which a fluorinated bank material (bank structure layer 12) is spin coated onto an anode (surface layer 11) (eg, ITO) and photopatterned to provide a well (see The area above the surface layer region 13). The photoresist layer 14 over the bank material is then photopatterned and additional processing is performed to remove the sections of the bank, thereby extending the insulating bank bracket. This additional processing can include reactive ion etching that is partially applied through the bank material by application for etching. The photoresist is removed after additional processing. The contour of the bank material at the edge of the well can thus be varied such that the profile provides a longer path length. As shown by only illustrative thin lines along the first bevel s1 and the second bevel s2 in FIG. 1, the etching results in a longer electrical path to the surface 15 exposed by the photoresist.

The alternative shown in Figure 1b uses a single masking step with a portion of the transmissive region in the mask to define a long anode to cathode distance for the bank of the bank; the RIE step preferably etches a thin positive masking layer therein The edge of the pixel. The RIE can etch the pixels where the edges of the pixels are exposed to the plasma due to the thin masking layer. Can use this method by changing The amount of masked design of the developed bank pixels relative to the size of the RIE patterned openings is used to adjust the anode to cathode distance and thus the amount of parasitic leakage current. This is in contrast to simple photo-patterned bank pixels and/or simple RIE patterned bank pixels, each of which will typically give a short path length from the anode to the cathode (blue region) and its length is typically not adjustable. Specifically, FIG. 1b shows surface layer 21, bank structure layer 22, surface layer region 23, photoresist layer 24, slopes s1 and s2, and surface 25.

(Fig. 1c shows RIE patterned bank pixels (upper to intermediate pattern) with short sidewall path lengths and conversely, fabrication of pixels (lowermost pattern) providing longer path lengths according to an embodiment).

Figure 1d shows a bank formed from a process embodiment as set forth above and further comprising a solution processable layer L1 in the form of a HIL (hole injection layer) and as an IL (intermediate layer) and/or LEP (light emitting polymer) Another device in the form of a layer that can treat layer L2. As seen in Figure 1d, the HIL, IL and LEP fluids have coincident pinning points. The IL and/or LEP layer may be covered by an EIL (electron injection layer), which in turn may be covered by a cathode layer. Preferably, the EIL does not share the pinning points of layers L1 and L2, but covers the layers and extends across adjacent regions of the bank structure. The cathode layer may preferably be deposited directly onto the EIL, which in an embodiment conformally coats the EIL to extend across the layers and the adjacent regions.

In view of the above, the embodiments provide a single bank structure having a long insulating bracket in contrast to a double bank system that separates the anode pinning point from the cathode. A single hydrophobic bank can be used and a subsequent patterning process applied to elongate the bank bracket. In an embodiment, the ITO and bank brackets may be hydrophilic to allow the HIL to wet until a predefined point where the bank becomes hydrophobic (ink pinning point). The section of the HIL will have a bank below the HIL pinning point that will share this pinning point with the IL and LEP. By using a high-resistance HIL, the active anode can be separated from the cathode for a long (and device-designable) distance.

Embodiments allow the anode to cathode path length to be increased in a controlled manner and thus provide a tunable process to reduce parasitic leakage current, which results in a more stable life test (and repeatable) device illumination. In contrast, a single bank formed by a standard photolithography process or a more complex but standard RIE (Reactive Ion Etch) process can provide an inexpensive method for pixel (deck) definition. However, two standard techniques allow the short anode to cathode path length to be maintained at the edge of the pixel (device). The short path length (short bracket) between the anode (ITO) surface and the HIL-IL-EL-cathode coincident pinning point has been shown to cause an unstable device when driven over time.

Another alternative of Figure 1a is considered to be an embodiment of a process flow for a single bank having a long bracket. The process involves a two-step patterning process to create a long bank bracket. The length of the carrier from the anode (ITO) to the ink pinning point can be controlled by a secondary patterning step, and the depth of the carrier can be similarly controlled to provide sufficient electrical isolation from the anode. This embodiment can be used to adjust the anode to cathode distance (see only illustrative thin lines) and thereby adjust parasitic leakage by varying the masked design size of the developed bank pixels relative to the pixel size of the secondary portion patterning step (see only illustrative thin lines) The amount of current. And, for example, simple light-patterned bank pixels or simple RIE patterned bank pixels (each of which will typically give a short path length (<1 μm) from the anode to the cathode and the length is typically not adjustable ( This embodiment produces a long bracket arrangement (e.g., > 2 [mu]m), in addition to the height of the bank.

A longer anode to cathode distance can also be achieved by making the bank higher, however, this will generally have a negative impact on the HIL-IL-EL profile at the edge of the pixel, making it thicker and causing uneven emission.

Preferably, the HIL, IL and EL of the embodiment all have coincident pinning points. This can result in a long leakage path from the anode to the cathode where the HIL (conductive hole injection layer) is in contact with the metal cathode. This effect is minimized by using a high resistance HIL and then separating the anode (ITO) from the cathode to achieve a long lateral HIL distance (as described above).

Considering the results of the device, the stability of the device during the life test showed a significant improvement. In an embodiment, the long bracket significantly reduces the pixel edge diode effect (which is a non-emissive thin diode) by increasing the resistance (path length) to a point at which the HIL-IL-EL conforms.

Figure 2 shows a graph of service life (device stability). It can be seen that the initial bright wave (increased illumination at a fixed current) for a single bank short bracket device (dashed curve) is significantly different between the devices. This may be due to the presence of a vertical leak path that "burns out" during the test, causing the current to be redistributed. In Figure 2, a single bank terminator (continuous curve) shows a much tighter distribution of bright wave magnitudes, which means that this effect may be independent of leakage current. It is possible to use this dike to evaluate materials and process stability. For a single bank bay configuration, lifetime (device degradation) is more predictable and much less dependent on pixel edge device effects. Therefore, a single hydrophobic bank with a long bracket has proven to be an improvement with regard to the stability of the life of the OLED.

Considering the complexity of the process, it should be noted that the simplified process method can produce a single hydrophobic single bank of long brackets, and/or reduce the size of the single bank by having a long insulating bracket to reduce leakage. The complexity of the construction. Advantageously, this simplified embodiment allows the anode to cathode path to grow in a controlled manner and thus tunably reduce parasitic leakage current, which reduces device efficiency. Embodiments encompass an alternative simplified method of achieving a single bank pixel.

Further focusing on process complexity, the process of Figure 1a involves a developed hydrophobic bank via secondary layer patterning and partial reactive ion etching (RIE). This may require two lithographic patterning loops (eg, cleaning, baking, coating, baking, exposing, baking, developing, embankment curing, coating, exposure, development) plus RIE steps and positive resist Agent stripping.

However, for example, the embodiment of FIG. 1b can be compared to an embodiment of a long bracket (as shown in FIG. 1a) required to use two photo-patterning steps plus reactive ion etching to create OLED device stability. A simplified process for providing a single slab of a single developed hydrophobic bank.

However, the first simplification shown in Figure Ib shows an unpatterned hydrophobic bank with partially exposed pixel edges due to the RIE masking layer. This process eliminates the need for masking and development steps on the first patterned loop.

An alternative simplification is shown in Figure 3a, which is illustrated as a dual development process. This process can be eliminated In addition to the need for RIE and stripping steps. Preferably, the first patterned bank is thin with a shallow bevel to the pixel. Preferably, the first thin bank layer is deposited, such as spin coated and hardened. The thin layer is then photopatterned and subsequently developed to expose the area of the anode having a gentle slope to the exposed areas. The other bank layer is then deposited, photopatterned and developed. Advantageously, a species such as a fluorine species (eg, a fluorine moiety) within the other bank layer migrates to the top surface of the other bank layer during baking of the other layer such that the top surface and the other bank The sidewalls of the layer, preferably also the sidewalls of the layer, are less wettable by the solution deposited on the exposed areas. Specifically, Figure 3a shows a surface layer 31, a first bank layer 32, a surface layer region 33, a second bank layer having a surface 34 and slopes s1 and s2.

Figure 3b shows an alternative simplification in the form of a double mask process using a single patterned layer. This does not use a single patterning step process of the positive resist layer, but it may require two light masks and a double exposure step. The upper mask (mask 2) may be a gradient mask to define the slopes s1 and s2 more clearly. Specifically, Figure 3b shows a surface layer 41, a bank layer 42, a surface layer region 43, slopes s1 and s2, and a surface 45, wherein the region 44 is between the bank layer 44 or below the surface 45 ( a number) a second region of the first region.

Figure 3c shows another alternative simplification: a single mask partial transmission (leakage) process using a single patterned layer. This does not use a single patterning step process of the positive resist layer, but it may require a higher cost light mask, but using a single exposure step. Specifically, Figure 3c shows surface layer 51, bank layer 52, surface layer region 53, ramps s1 and s2, and surface 55, wherein region 54 is between the banks 54 or below surface 55. a number) a second region of the first region. Partially transmissive (eg, sub-resolution characterization) masks may be gradient masks to more clearly define the slopes s1 and s2.

Figure 3d shows yet another alternative simplification: a single masking process using a single patterned layer using a reflective region and a secondary threshold exposure dose. This is a single patterning step process that does not use a positive resist layer but uses a single exposure step. The design of the above layers may incorporate reflective regions for creating higher dose regions to completely cross the banks. This method can be used to adjust the anode to The cathode distance and thus the amount of parasitic leakage current is adjusted. Specifically, FIG. 3d shows a surface layer 61, a bank layer 62, a surface layer region 63, slopes s1 and s2, and a surface 65, wherein the region 64 is a first region of the bank layer opposite to the surface 65 (several) The second area.

This is in contrast to photo-patterning a single bank pixel and/or RIE patterned bank pixel, each of which will typically give a short path length from the anode to the cathode (blue region) and its length is typically not adjustable (see Figure 1c).

For various methods and embodiments as described above, FIG. 4 shows a plurality of example cradle embankment images. Figure 4a shows a double-developed long bay embankment, Figure 4b shows a double-developed long bay embankment with HIL, Figure 4c shows a long bay embankment with a recess through RIE, and Figure 4d shows a single developed dike And Figure 4e shows a single developed bank with HIL (short (none) bracket).

The flat thickness variation curve of HIL+IL is desirable to maximize the effectiveness of the OLED device on the microcavity platform. In an ink jet printing apparatus, the thickness variation curve depends on the underwall structure. This details the preferred bank profile to achieve a suitable flat thickness variation curve in a single bank inkjet printing apparatus. Advantageously, this profile can provide a gradual transition from the bank of the bank to the active zone, thereby allowing the printed HIL to form a flat profile suitable for the microcavity OLED device.

Specifically considering the use of a flat carrier profile with a gradient carrier single bank + waterless HIL, embodiments can provide a gradual transition from the bank of the bank to the active zone, thus allowing the printed HIL to form a flat profile suitable for a microcavity OLED device. The flat thickness variation curve of HIL+IL is desirable to maximize the effectiveness of the OLED device on the microcavity platform. In an ink jet printing apparatus, the thickness variation curve depends on the underwall structure. Embodiments provide a bank profile for achieving a suitable flat thickness variation curve in a single bank inkjet printing device.

The maximum performance at the point where the best possible color point is achieved typically requires precise control of layer thickness and profile in the microcavity OLED device. Furthermore, if there is significant non-uniformity in the contour region of the HIL+IL layer, then non-optimal output coupling will occur and performance will suffer.

For example, a width profile of the HIL+IL thickness of an inkjet printing device is shown in FIG. The edge region display of the visible pixel is significantly thicker than the central region. The CIE coordinates are shifted according to the target color point in these areas. This results in a compromise of overall device performance.

The type of bank has been developed to minimize the amount of edge thickening and thus improve printing performance. The sharp transition from the carrier to the ITO causes the edge to thicken due to the inability of the HIL to closely follow the contour of the bank.

An embodiment with a tapered bank bracket is shown in Figure 6, which is shown in a lower view with a close-up view of the upper annular region, wherein in the lower hand side lower view the embodiment is shown with no gradient tilt (left hand side) This tilt.

The use of this gradient cradle type has been shown to maximize the effectiveness of the device on the inkjet printing platform, making it comparable to SC (spin coating) data (showing information for devices that emit green light):

Where DE = D (u'v') is defined using u', v' ("CIELUV") in the CIE 1976 color space. The watch shows that an inkjet printing device such as a gradient cradle device has an performance comparable to that of a spin coating device.

Further in this regard, attention should be paid to the conversion from CIExy of the 1931 CIE XYZ color space to CIE u'v' of CIELUV (ie, CIE1931→CIE1976): And by using the color difference metric DE defined by u', v' of CIELUV, the following: , that is, the Euclidean distance in the CIE 1976 space.

For embodiments such as the "gradient cradle embankment" device described above, the CIEx and y targets (NTSC) for green emission are 0.213 and 0.724, respectively. CIExy was obtained using a Minolta colorimeter, and dE was calculated using CIExy.

dE = 0.02 is a preferred upper limit acceptable in the examples, however, 0.005, 0.01 or 0.015 is more desirable.

Figure 7 shows a histogram showing that the standard bank has a larger ratio of thicker regions than the embodiment with the tapered bracket bank. The histogram is obtained by measuring the thickness at regularly spaced points across the upper active area above the surface layer region surrounded by the sidewalls of the bank structure. The device having the "standard bank" is a device having a long bracket of substantially constant thickness similar to that shown in the upper portion of Fig. 6. A device having a "deck" has a long bracket that tapers toward the surface layer of the device, such as a first bevel having an angle of preferably less than 5, 10, 15, or 20 degrees. The "deck" device has a narrower thickness distribution than the "standard bank" device, thus allowing for more controlled output coupling in the OLED (input coupling in the light absorbing device).

There is no doubt that those skilled in the art will come up with many other effective alternatives. It is to be understood that the invention is not to be construed as being limited to

11‧‧‧ surface layer

12‧‧‧deck structural layer

13‧‧‧Surface area

14‧‧‧ photoresist layer

15‧‧‧ surface

S1‧‧‧ first bevel

S2‧‧‧Second slope

Claims (15)

A method of fabricating an electronic device comprising a surface layer and a substrate defining a bank structure of the well on the surface layer, the bank structure comprising an electrically insulating material and having a region surrounding the surface layer to thereby define the well a sidewall, the surface layer region comprising a first electrode, and the device further comprising a second electrode and a semiconducting material disposed between the first electrode and the second electrode, the method comprising: forming having a surface layer included a bank structure of the sidewall of the first bevel extending from the first bevel and the second bevel extending from the first bevel, wherein the second bevel is steeper than the first bevel, wherein the sidewall has the second bevel a surface energy discontinuity at a point at which the first bevel is spaced apart; forming a layer structure having at least one layer disposed between the first electrode and the second electrode and having the semiconducting material, wherein the layer Forming the layer structure includes: depositing an organic solution on the surface layer region and the first slope surface and the second slope surface of the sidewall to form a solution processable layer, wherein the sinking The organic solution wetting the first inclined plane and the second inclined surface until the staple of the discontinuity of the surface energy of tie points; and drying the deposited organic solution. The method of claim 1, comprising: depositing at least another solution over the solution processable layer, wherein the at least one other solution wets up to the pinning point; and drying the deposited at least one other solution. The method of claim 1 or 2, wherein the forming the bank structure comprises: forming a first bank layer comprising a photoresist on the surface layer of the substrate; photo patterning and developing the first bank layer Exposing the region of the surface layer; depositing the fluorinated photoresist solution onto the first bank layer and the surface layer Forming a second bank layer on the region; baking to harden the second bank layer, wherein the fluorine-containing compound of the fluorinated photoresist solution migrates to the second bank layer during the baking a surface to increase a contact angle of the organic solution with the surface; and photo patterning and developing the second bank layer to re-expose the region of the surface layer and exposing a region of the first bank layer such that the first The bank layer region has the first slope and the second bank layer has the second slope, wherein the increased contact angle is higher than a contact angle between the organic solution and the first slope and the second slope, and the nail The tie is at the boundary of the surface of the second bank layer having the migrated fluorine-containing compound. The method of claim 1 or 2, wherein the forming the bank structure comprises: forming a bank structure layer by depositing a fluorinated photoresist solution on the surface layer, and drying the deposited solution to make the bank portion The structural layer is hardened, wherein the fluorine-containing compound of the fluorinated photoresist solution migrates to the surface of the bank structure layer during the baking to increase the contact angle of the organic solution with the surface; on the bank structure layer Depositing and drying a photoresist layer, and photo patterning and developing the photoresist layer; a dry etching step for etching the bank structure layer through the developed photoresist layer to expose the surface layer region, such that The etched bank structure layer has the sidewall surrounding the exposed surface layer region and includes the first slope and the second slope; and removing the developed photoresist layer to expose the surface of the bank structure layer, The exposed surface includes the migrated fluorine-containing compound, wherein the surface energy discontinuity is at an interface between the exposed surface comprising the migrated fluorine-containing compound and the etched sidewall. The method of claim 4, wherein the forming the bank structure comprises: Developing and photo patterning the bank structure layer to expose the surface layer region surrounded by sidewalls of the bank structure layer, wherein depositing the photoresist layer on the bank structure layer is included in the photopatterned bank Depositing a photoresist solution on the structural layer, and developing the photoresist layer includes re-exposing the surface layer region, and the dry etching step for exposing the surface layer region is performed by thinning the bank structure layer Forming the first bevel and the second bevel to extend the exposed region; preferably wherein the photo patterning the photoresist layer comprises passing through a non-transmissive region, a partially transmissive region, and a fully transmissive region The mask radiates the photoresist layer; and developing the photoresist layer includes completely removing one region of the photoresist and partially removing the photoresist region exposed to the radiation through the portion of the transmissive region; Preferably, the dry etching step comprises reactive ion etching preferably using an oxygen plasma. The method of claim 1, wherein the forming the bank structure comprises: forming a bank layer by depositing a fluorinated photoresist solution on the surface layer; baking to harden the bank layer, wherein The fluorine compound of the photoresist solution migrates to the surface of the bank layer during the baking to thereby increase the contact angle of the organic solution with the surface; the light patterning the hardened bank layer, the light patterning includes The first radiation dose radiates a first region of the bank layer and the second region of the bank layer is irradiated with a second radiation dose, the second radiation dose being less than the first radiation dose; developing the bank layer to expose the surface a region of the layer and partially removing an area of the bank layer that is irradiated with the second radiation dose, the portion being removed thereby providing the surrounding area and having the first bevel and the second bevel a sidewall, wherein the pinning point is in the bank layer having the migrated fluorine-containing compound The boundary between the face and the side wall. The method of claim 6, wherein: the patterning of the light comprises simultaneously radiating the bank layer through the first mask and the second mask, wherein the radiating the first region at the first dose comprises passing the first The mask and the fully transmissive region of the second mask radiate the first region, and the radiating the second region at the second dose includes passing through each of the first mask and the second mask At least a portion of the transmissive region radiates the second region; and/or the photo patterning includes radiating the embankment layer through a mask having a partially transmissive region and a more transmissive region, wherein the first dose is radiated The first region includes radiating the first region through the more transmissive region, and the radiating the second region at the second dose includes radiating the second region through the partially transmissive region; and/or the method Including depositing a reflector layer on a region of the surface layer, wherein: depositing the fluorinated photoresist solution deposits the fluorinated solution on the reflector layer and the surface layer; and the photo patterning comprises passing through the mask The cover radiates the bank layer, wherein the radiation of the first region package The first portion of the region directly absorbed through the mask receiving the first dose of the mask and is absorbed from the first receiving reflected by the reflector layer back to a portion of the first region of the dosage. The method of any one of claims 1, 2, 6 and 7, wherein the electronic device is an optoelectronic device, such as a light emitting device or a light absorbing device, preferably a light absorbing device such as an organic photovoltaic device (OPV) or such as organic A light-emitting device of a light-emitting diode (OLED). The method of any one of claims 1, 2, 6 and 7, wherein the electronic device is an OLED and the organic solution is used to provide a hole injection layer (HIL), the method preferably being included in the solution processable layer Forming at least another solution processable layer between the first electrode and the second electrode, the other solution processable The layers are used to provide an intermediate layer (IL) and/or an illuminating layer (EL). The method of any one of claims 1, 2, 6 and 7, wherein: the organic solution is at least one of a first bevel deposited on the first bevel and a second bevel extending from the first bevel to the pinning point The contact angle is 10° or less; and/or wherein the organic solution has a contact angle of 50° when deposited on a region of the bank structure extending from the pinning point away from the first slope Or bigger. An electronic device comprising a substrate having a surface layer and a bank structure defining a well on the surface layer, the bank structure comprising an electrically insulating material and having an area surrounding the surface layer to thereby define a sidewall of the well, The surface layer region includes a first electrode, and the device further includes a second electrode and a semiconductive material disposed between the first electrode and the second electrode, wherein: the sidewall has a first extension from the surface layer region a bevel and a second bevel extending from the first bevel, wherein the second bevel is steeper than the first bevel; and the device comprises a layer structure having at least one layer, at least one of the layers being a solutionable layer, the layer structure Having the semiconducting material and disposed between the first electrode and the second electrode, wherein: at least one of the solution treatable layers has a pinning at a point spaced apart from the first bevel on the second bevel The solution layer is disposed on the surface layer region and the first slope and the second slope of the sidewall. The electronic device of claim 11, wherein the bank structure comprises at least one photoresist layer, preferably wherein: the photoresist layer has the point on the second slope and comprises a fluorine-containing compound; and/or The bank structure includes a plurality of photoresist layers, the photoresist layer having the first slope; and/or The bank structure includes the photoresist layer having the fluorine-containing compound and the first slope and the second slope. The electronic device of any of claims 11 to 12, wherein the first bevel has a bevel angle of less than or equal to 20 degrees, more preferably less than 10 degrees, relative to the surface layer. The electronic device of any one of claims 11 to 12, wherein: the first slope extends to a thickness of the bank structure of less than 300 nm, preferably less than 200 nm, at a boundary with the second slope, preferably At least one of the first bevel and the second bevel extends along a thickness of the bank structure from 100 nm to 150 nm; and/or the sidewall extends from the surface region to provide a bank structure thickness of at least 300 nm; and/or the A bevel extends across the surface layer for a length of at least 1 μm, preferably wherein the second bevel extends along the surface layer for a length of at least 8 μm, preferably wherein the sidewall extends across the surface layer A length of at least 10 μm. The electronic device of any one of claims 11 to 12, wherein the device is a light emitting device, and wherein the solution processable layer comprises an organic semiconductive material for providing a hole injection layer (HIL), preferably wherein The illumination device is an OLED, preferably wherein at least one of the solution processable layers comprises another organic semiconducting material disposed over the material for providing the HIL, and the other organic semiconducting material is used to provide Intermediate layer (IL) or luminescent layer (EL).