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CN-116149138-B - Preparation method of mixed photoresist and metal electrode

CN116149138BCN 116149138 BCN116149138 BCN 116149138BCN-116149138-B

Abstract

The application provides a preparation method of a mixed photoresist and a metal electrode, and relates to the technical field of luminescence. The raw materials of the mixed photoresist comprise negative photoresist and extinction photoresist, and the volume ratio of the negative photoresist to the extinction photoresist is (2.5-3.5): 1. The preparation method of the metal electrode comprises the steps of performing first coating on the surface of a set structure by using negative photoresist to obtain a first photoresist layer, continuously performing second coating by using mixed photoresist to obtain a second photoresist layer, exposing the double-layer photoresist layer to obtain a double-layer photoresist layer with a set pattern, setting a metal layer on the second photoresist layer with the set pattern, and stripping the double-layer photoresist layer under the metal layer to obtain the metal electrode.

Inventors

  • SUN ZHENG

Assignees

  • 深圳市思坦科技有限公司

Dates

Publication Date
20260512
Application Date
20230218

Claims (8)

  1. 1. A method of making a metal electrode, the method comprising: Performing first coating on the surface of the set structure by using negative photoresist to obtain a first photoresist layer; Performing second coating on the surface of the first photoresist layer by using mixed photoresist to obtain a second photoresist layer; exposing the first photoresist layer and the second photoresist layer to obtain the first photoresist layer and the second photoresist layer with set patterns; providing a metal layer on the second photoresist layer with the set pattern; stripping the first photoresist layer and the second photoresist layer below the metal layer to obtain a metal film layer which is a metal electrode; the raw materials of the mixed photoresist comprise negative photoresist and extinction photoresist, and the volume ratio of the negative photoresist to the extinction photoresist in the mixed photoresist is (2.5-3.5): 1; The extinction photoresist includes a black photoresist.
  2. 2. The method of claim 1, wherein the exposure dose is 80mJ/cm 2 -100mJ/cm 2 .
  3. 3. The method of claim 1 or 2, wherein the first thickness of the first photoresist layer and the second photoresist layer after being stacked is 1.5 to 2 times the second thickness of the metal film layer.
  4. 4. The method according to claim 1, wherein after the first coating, the method further comprises a pre-baking treatment of the negative photoresist; And after the second coating, performing pre-baking treatment on the mixed photoresist.
  5. 5. The method of preparation of claim 1, wherein the method comprises at least one of the following conditions: a. the first coating and the second coating each independently comprise preparation using a spin-coating process; b. the spin coating process comprises the steps of performing first low-speed spin coating, then performing high-speed spin coating, and then performing second low-speed spin coating; c. the spin speeds of the first low-speed spin coating and the second low-speed spin coating are 300rpm-500rpm, and the spin time is 5s-10s; d. the spin-coating rotating speed of the high-speed spin coating is 1500rpm-2500rpm, and the spin-coating time is 50s-70s; e. The method further comprises the steps of performing pre-baking treatment on the negative photoresist for 2-4 min at 100-120 ℃; f. The step of performing the second coating, which further comprises the step of performing pre-baking treatment on the mixed photoresist for 3-5 min at the temperature of 100-120 ℃; g. The thickness of the first photoresist layer is 6-8 mu m, the thickness of the second photoresist layer is 1-2 mu m, and the total thickness of the photoresist layers after the first photoresist layer and the second photoresist layer are overlapped is 3-4 mu m; h. The exposure is further carried out by baking at 100-120 ℃ for 5-10 min, then putting into developing solution for development, taking out, and then carrying out post-baking at 100-120 ℃ for 3-5 min.
  6. 6. The preparation method of the miniature LED chip is characterized by comprising the steps of providing a miniature LED epitaxial wafer and etching a mesa structure on the miniature LED epitaxial wafer; preparing a metal electrode on the surface of the mesa structure by using the preparation method of the metal electrode in any one of claims 1-5; And preparing a passivation layer on the surface of the metal electrode, and etching the passivation layer to obtain an electrode contact hole.
  7. 7. The method of manufacturing a micro LED chip as set forth in claim 6, wherein at least one of the following conditions is also satisfied: g. The miniature LED epitaxial wafer comprises a substrate, a buffer layer, a third semiconductor layer, a first semiconductor layer, a multiple quantum well structure and a second semiconductor layer from bottom to top in sequence; h. Removing part of the second semiconductor layer and the multiple quantum well structure on the miniature LED epitaxial wafer by adopting an inductive coupling plasma etching method to expose the first semiconductor layer; i. The preparation method of the passivation layer comprises a plasma enhanced chemical vapor deposition method; j. The etching includes a process using dry and/or wet etching.
  8. 8. A micro LED chip, characterized in that it is manufactured by using the manufacturing method of the micro LED chip according to claim 6 or 7.

Description

Preparation method of mixed photoresist and metal electrode Technical Field The application relates to the technical field of luminescence, in particular to a preparation method of a mixed photoresist and a metal electrode. Background The micro LED display technology is a display technology in which self-luminous micro LEDs are used as light-emitting pixel units, and the light-emitting pixel units are assembled on a driving panel to form a high-density LED array. The display device has the characteristics of high brightness, high luminous efficiency, high contrast ratio, quick response, long service life, high color gamut, self-luminescence, seamless splicing and the like, and has performances far higher than those of the existing LCD and OLED display devices, and is considered as the next generation display technology following the LCD and OLED. The micro LED has the characteristic of self-luminescence, does not need a backlight source, is easier to debug in color compared with an OLED, and has higher resolution (1500 ppi), faster response speed (ns level), longer service life and higher brightness. However, in the prior art, the electrode size precision of the high resolution micro light emitting device is not high. Disclosure of Invention The application aims to provide a preparation method of a mixed photoresist and a metal electrode. The mixed photoresist capable of reducing the light intensity is provided and used on the surface of the negative photoresist layer in the Lift-off process, so that the photoetching exposure dose when light reaches the negative photoresist layer is reduced, the exposure intensity of the negative photoresist layer is reduced, the photoetching precision of the negative photoresist layer is improved, and the dimensional precision of the metal electrode is further improved. In order to achieve the above object, the technical scheme of the present application is as follows: In a first aspect, the application provides a hybrid photoresist, the raw materials of which comprise negative photoresist and extinction photoresist, wherein the volume ratio of the negative photoresist to the extinction photoresist in the hybrid photoresist is (2.5-3.5): 1. Preferably, the extinction photoresist comprises black photoresist. In a second aspect, the present application provides a method for preparing a metal electrode, the method comprising: Performing first coating on the surface of the set structure by using negative photoresist to obtain a first photoresist layer; Performing second coating on the surface of the first photoresist layer by using a mixed photoresist to obtain a second photoresist layer, wherein the mixed photoresist comprises the mixed photoresist of the first aspect; exposing the first photoresist layer and the second photoresist layer to obtain the first photoresist layer and the second photoresist layer with set patterns respectively; providing a metal layer on the second photoresist layer with the set pattern; and stripping the first photoresist layer and the second photoresist layer below the metal layer to obtain a metal film layer which is a metal electrode. Preferably, the exposure dose of the exposure is 80mJ/cm 2-100mJ/cm2. Preferably, the first thickness of the sum of the first photoresist layer and the second photoresist layer is 1.5 to 2 times the second thickness of the metal film layer. Preferably, after the first coating, the method further comprises the step of performing pre-baking treatment on the negative photoresist; And after the second coating, performing pre-baking treatment on the mixed photoresist. Preferably, the method further comprises at least one of the following conditions: a. the first coating and the second coating each independently comprise preparation using a spin-coating process; b. the spin coating process comprises the steps of performing first low-speed spin coating, then performing high-speed spin coating, and then performing second low-speed spin coating; c. the spin speeds of the first low-speed spin coating and the second low-speed spin coating are 300rpm-500rpm, and the spin time is 5s-10s; d. the spin-coating rotating speed of the high-speed spin coating is 1500rpm-2500rpm, and the spin-coating time is 50s-70s; e. the method further comprises the steps of pre-baking the negative photoresist for 2-4 min at 100-120 ℃; f. the step of performing the second coating, which further comprises the step of performing pre-baking treatment on the mixed photoresist for 3-5 min at the temperature of 100-120 ℃; g. The thickness of the first photoresist layer is 6-8 mu m, the thickness of the second photoresist layer is 1-2 mu m, and the total thickness of the photoresist layers after the first photoresist layer and the second photoresist layer are overlapped is 3-4 mu m; h. The exposure is further carried out by baking at 100-120 ℃ for 5-10 min, then putting into developing solution for development, taking out, and then carrying out post-bakin