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KR-102962880-B1 - Three-layer photoresist system and method for organic device patterning

KR102962880B1KR 102962880 B1KR102962880 B1KR 102962880B1KR-102962880-B1

Abstract

Design and method of a trilayer resist system for patterning an organic device including an organic light-emitting diode (OLED) device suitable for a high-resolution light field display. The trilayer resist system comprises a fluoropolymer base layer, an inorganic transfer layer, and an upper positive photoresist layer that protects the organic material formed on the substrate from damage caused by radiation, developer, and solvent used in traditional photolithography techniques, thereby creating a high-resolution multi-color OLED array.

Inventors

  • 바흐만, 다니엘
  • 왕, 첸슈
  • 마디, 모하마드

Assignees

  • 아발론 홀로그래픽스 인크.

Dates

Publication Date
20260508
Application Date
20220630
Priority Date
20210702

Claims (20)

  1. As a method for patterning an organic device, Step of depositing a bottom electrode on a substrate; A step of depositing a triple-layer resist system on a substrate, wherein the triple-layer resist system is: Fluoropolymer base layer; Intermediate weapon warrior layer; and A deposition step comprising an upper positive type photoresist layer; and As a step of creating at least one organic device, the organic device is: Patterning an upper positive-type photoresist layer using photolithography to create an image layer aligned with a bottom electrode; Etching the intermediate weapon transfer layer exposed through the image layer; Etching the fluoropolymer base layer exposed through the inorganic transfer layer to expose the bottom electrode using reactive ion etching; Depositing at least one organic layer on the exposed bottom electrode; Perform a lift-off procedure to remove the remaining components of the triple-layer resist system; and A step of producing at least one organic device produced by depositing an upper electrode on top of an organic layer; method.
  2. In paragraph 1, The above organic device is an organic light-emitting diode, method.
  3. In paragraph 1, The above organic device is an organic field-effect transistor, an organic solar cell, a photovoltaic device, an organic semiconductor, or an organic laser. method.
  4. In any one of paragraphs 1 through 3, The above fluoropolymer base layer has a visible light transmittance of 95% or more, method.
  5. In any one of paragraphs 1 through 3, The above positive type photoresist layer has a thickness between 340 and 500 nm, method.
  6. In any one of paragraphs 1 through 3, Etching the inorganic transfer layer through the patterned positive photoresist layer creates an undercut region between the positive photoresist image layer and the inorganic transfer layer, method.
  7. In any one of paragraphs 1 through 3, Etching the above fluoropolymer base layer generates a lateral undercut profile and a longitudinal undercut profile, method.
  8. In Paragraph 7, The above lateral undercut profile has a length of ≥0.25μm, method.
  9. In any one of paragraphs 1 through 3, The above lift-off procedure utilizes a fluorinated solvent to dissolve the fluoropolymer base layer, method.
  10. In any one of paragraphs 1 through 3, The above-mentioned inorganic transfer layer comprises one or more of metals and dielectric materials, method.
  11. In any one of paragraphs 1 through 3, At least one of the organic layers comprises one or more electron transport layers (ETL), emission layers (EML), hole transport layers (HTL), and hole injection layers (HIL). method.
  12. In Paragraph 11, The above-mentioned emission layer (EML) emits at least one of red, green, and blue colors. method.
  13. In any one of paragraphs 1 through 3, An oxide layer is deposited on a substrate and an electrode array prior to the deposition of the above-mentioned triple-layer resist system, method.
  14. In Paragraph 13, The oxide layer comprises a transparent conductive oxide, method.
  15. As a method for patterning an array of organic devices, A step of depositing an array of bottom electrodes on a substrate; A step of depositing a trilayer resist system on a substrate using a trilayer resist deposition method, wherein the trilayer resist system is: Fluoropolymer base layer; Intermediate weapon warrior layer; and A deposition step comprising an upper positive type photoresist layer; and A step of generating a plurality of organic devices for a first set of organic devices using an organic device deposition method, wherein the organic device deposition method is: A step of patterning an upper positive-type photoresist layer using photolithography to create an image layer aligned with a set of arrays of bottom electrodes; A step of etching the intermediate weapon transfer layer exposed through the image layer; A step of etching a fluoropolymer base layer exposed through an inorganic transfer layer using reactive ion etching to expose a set of arrays of bottom electrodes; A step of depositing at least one organic layer on a set of exposed bottom electrodes; A step of creating a plurality of organic devices, comprising: a step of performing a lift-off procedure to remove the remaining components of a triple-layer resist system; A step of repeating a triple-layer resist deposition method to deposit a triple-layer resist system on a substrate; A step of repeating an organic device deposition method to produce a second set of organic devices aligned with a second set of bottom electrodes; and A step of repeating the lift-off procedure to remove the remaining components of the triple-layer resist system; comprising method.
  16. In paragraph 15, A further step of depositing an upper electrode on the upper surface of each organic device, method.
  17. In paragraph 15 or 16, The organic device is an OLED, and the first set of organic devices and the second set of organic devices emit different colors, method.
  18. In paragraph 15 or 16, Etching the inorganic transfer layer through the patterned positive-type photoresist image layer forms an undercut region between the positive-type photoresist image layer and the inorganic transfer layer. method.
  19. In paragraph 15 or 16, Etching the fluoropolymer base layer generates lateral undercut profiles and longitudinal undercut profiles, method.
  20. In Paragraph 19, The lateral undercut profile has a length of ≥0.25μm, method.

Description

Three-layer photoresist system and method for organic device patterning Cross-reference regarding related applications This application claims priority to U.S. Patent Application No. 63/217,776 filed July 2, 2021, the entire contents of which are incorporated herein by reference. Technology field The present disclosure relates to semiconductor processing technology, and in particular to photolithography technology using a photoresist system to pattern an organic device. Due to the sensitivity of organic materials to temperature and other materials, organic light-emitting diodes (OLEDs) are inherently difficult to pattern. These structures are traditionally deposited using evaporation through a shadow mask. Deposition through a shadow mask typically involves placing a template in front of a substrate that blocks the substrate everywhere except for the desired deposition location for the OLED material. Traditional patterning methods, such as lithography, are generally not used because OLEDs are composed of organic materials that are susceptible to dissolution or degradation by the solvents required for photoresist technology found in conventional lithography. If these limitations did not exist, conventional lithography methods would be the simplest method for manufacturing OLED structures and other organic devices. Common deposition methods used to deposit and pattern organic devices, particularly OLED devices, involve the use of fine metal masks, which are a type of shadow mask. A shadow mask is typically a large sheet made as thin as possible with small holes. Deposition occurs through point sources where organic material evaporates onto the mask, and the organic material exiting through these holes terminates on the substrate at the appropriate location as directed by the mask. Among other things, limitations on how small the holes in the shadow mask can be, how thin the shadow mask can be made, and how close the shadow mask can be placed to the substrate result in resolution limits that restrict feature size and the density of the patterned organic material. Among the problems caused by the physical dimensions of the shadow mask is the shadowing effect, where material is deposited beneath the masked area of the shadow mask, while the unmasked area exhibits non-uniform deposition. The shadowing effect occurs during deposition beneath the physically masked area of the substrate because the evaporated material deviates from its normal arrival angle. The thickness of the shadow mask is a factor in determining the extent of unwanted shadowing effects on the substrate, which can lead to resolution limits for patterning organic materials. Therefore, it is desirable to use a very thin shadow mask, as there is a risk of the mask breaking or deforming if it is too thin. Due to the target dimensions of high-resolution OLEDs for optical field display technology, photolithography is a mature and well-developed ideal deposition technique often used for small-scale patterning of semiconductors and metals. However, it should be noted that materials generally used in semiconductor manufacturing, and metals in particular, are less sensitive to process than organic materials. Many microfabrication processes are designed to remove organic materials through development, and in many cases, organic materials are considered contaminants. In particular, standard photolithography cleaning procedures are designed to remove organic contaminants. There are specially manufactured resist systems that use solvents safe for organic materials. These specially designed systems typically utilize a two-layer photolithography lift-off method, where the bottom photolithography layer is used as a sacrificial layer and the top layer is a photosensitive resist layer. In one technique, the bottom layer is rotated and baked on a wafer before the top layer is rotated, baked, and patterned. The basis of this type of photoresist system is that the top and bottom layers can be dissolved in different solvents or at least at different rates in the same solvent, allowing each of the two layers to be selectively etched or removed. For the patterning of organic materials, a lift-off technique is often utilized to create an undercut profile in the photosensitive resist layer, thereby creating a cavity structure where the top layer of the resist protrudes over an opening in the bottom layer of the resist. The material to be lifted off is deposited through the opening, and the cavity beneath the overhanging resist profile leaves the deposited material in the patterned opening, leaving additional space for the solvent to access the resist system after the desired material has been deposited. It has been proven that exposure to ultraviolet (UV) light, which is required for photolithography processes used with specially manufactured resist systems, can damage OLED structures. Some organic safety resist systems use a negative photoresist top layer that must be exp