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CN-114937726-B - Micro LED chip and manufacturing method thereof

CN114937726BCN 114937726 BCN114937726 BCN 114937726BCN-114937726-B

Abstract

The invention relates to a MicroLED chip and a manufacturing method thereof, belonging to the technical field of semiconductors, and comprising a DBR reflecting layer, an epitaxial structure positioned on the DBR reflecting layer, a current blocking layer positioned on the epitaxial structure, a transparent conducting layer positioned on the epitaxial structure and the current blocking layer, an expansion electrode positioned on the transparent conducting layer, an insulating protective layer positioned on the DBR reflecting layer, the epitaxial structure, the current blocking layer, the transparent conducting layer and the expansion electrode, and a welding electrode positioned on the epitaxial structure, the expansion electrode and the insulating protective layer, thereby providing a novel chip structure, wherein the chip structure is a positive chip structure, the positive and negative welding electrodes are equal in height, and the MicroLED chip structure is expanded.

Inventors

  • WANG BINFEI
  • LIU LINQI

Assignees

  • 刘林启

Dates

Publication Date
20260512
Application Date
20220608

Claims (10)

  1. 1. The Micro LED chip is characterized by comprising a DBR reflecting layer, an epitaxial structure, a first current blocking layer, a second current blocking layer, a transparent conducting layer, a first extension electrode, a second extension electrode, an insulating protection layer, a first welding electrode and a second welding electrode; The epitaxial structure is arranged on the DBR reflecting layer, and an included angle of the epitaxial structure relative to the horizontal direction where the upper surface of the DBR reflecting layer is positioned is an acute angle, and the angle is 85-20 degrees; The first current blocking layer and the second current blocking layer are arranged on the epitaxial structure and are positioned at two ends of the epitaxial structure; The transparent conductive layer is arranged on the first current blocking layer, the second current blocking layer and the epitaxial structure between the first current blocking layer and the second current blocking layer; the first expansion electrode and the second expansion electrode are arranged on the transparent conductive layer at intervals; The insulating protection layer covers the outer surface of the structure consisting of the epitaxial structure, the first current blocking layer, the second current blocking layer, the transparent conductive layer, the first expansion electrode and the second expansion electrode and is in contact with the upper surface of the DBR reflecting layer which is not in contact with the epitaxial structure; A first opening and a second opening are reserved on the insulating protective layer; the first welding electrode is arranged on the insulating protection layer and is electrically connected with the first expansion electrode through the first opening; the second welding electrode is arranged on the insulating protection layer and is electrically connected with the epitaxial structure through the second opening; The first current blocking layer, the first extension electrode, and the first welding electrode correspond to each other, and the second current blocking layer, the second extension electrode, and the second welding electrode correspond to each other in a projection direction of the DBR reflection layer.
  2. 2. The chip of claim 1, wherein the DBR reflective layer comprises a plurality of films of different materials, the films are made of SiO 2 、SiN、TiO 2 、Ta 2 O 5 or MgF, and the DBR reflective layer has a thickness of 1.5-10 μm.
  3. 3. The chip of claim 1, wherein the epitaxial structure comprises a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in this order from bottom to top, wherein the first semiconductor layer and the second semiconductor layer are opposite in electrical property.
  4. 4. The chip of claim 1, wherein the materials of the first current blocking layer, the second current blocking layer, and the insulating protective layer are all insulating transparent materials, the insulating transparent materials including one or more of SiO 2 、SiN、TiO 2 、Ta 2 O 5 , mgF, hfO, and Al 2 O 3 ; the thickness of the first current blocking layer and the second current blocking layer is 50-20000A, and the thickness of the insulating protective layer is 2000-20000A.
  5. 5. The chip of claim 1, wherein the transparent conductive layer is made of ITO, gaO or ZnO, and the thickness of the transparent conductive layer is 100-3000A.
  6. 6. The chip of claim 1, wherein the first extension electrode and the second extension electrode have the same structure, and the first extension electrode comprises a bonding ohmic contact layer, a reflecting layer, a barrier layer, a current extension layer, an etching stop layer and a bonding layer which are sequentially stacked from bottom to top; The material of the bonding ohmic contact layer comprises one or more of Cr, ni and Ti, the thickness is 10-50A, the material of the reflecting layer comprises one or more of Al and Ag, the thickness is 500-3000A, the material of the blocking layer comprises one or more of Ti, pt and Ni, the thickness is 500-3000A, the material of the current expansion layer comprises one or more of Pt and Au, the thickness is 2000-30000A, the material of the etching stop layer comprises one or more of Pt and Ni, the thickness is 500-3000A, the material of the bonding layer comprises one or more of Ti and Ni, and the thickness is 500-3000A.
  7. 7. The chip of claim 1, wherein the first welding electrode and the second welding electrode have the same structure, and the first welding electrode comprises a bonding ohmic contact layer, a reflecting layer, a barrier layer and a welding layer which are sequentially laminated from bottom to top; The material of the bonding ohmic contact layer comprises one or more of Cr, ni and Ti, the thickness is 10-50A, the material of the reflecting layer comprises one or more of Al and Ag, the thickness is 500-3000A, the material of the blocking layer comprises one or more of Ti, pt and Ni, the thickness is 500-3000A, the material of the welding layer comprises one or more of Au, sn, in, ag, cu, and the thickness is 0.1-30 μm.
  8. 8. The chip of claim 1, wherein a spacing between the first current blocking layer and the second current blocking layer is 5-200 μm, a spacing between the first extension electrode and the second extension electrode is 5-200 μm, and a spacing between the first bonding electrode and the second bonding electrode is 5-200 μm.
  9. 9. A method for manufacturing a Micro LED chip, which is used for manufacturing the Micro LED chip according to claim 1, comprising the steps of: the method comprises the steps of providing an epitaxial wafer, wherein the epitaxial wafer comprises a growth substrate and an epitaxial structure which are sequentially stacked from bottom to top; manufacturing a first current blocking layer and a second current blocking layer on the epitaxial structure; Manufacturing transparent conductive layers on the first current blocking layer, the second current blocking layer and the epitaxial structure; Manufacturing a first expansion electrode and a second expansion electrode on the transparent conductive layer; manufacturing insulating protection layers on the growth substrate, the epitaxial structure, the first current blocking layer, the second current blocking layer, the transparent conducting layer, the first expansion electrode and the second expansion electrode; Etching a partial region of the insulating protective layer to form a first opening and a second opening, wherein the first opening is used for exposing a part of the first extension electrode; Manufacturing a first welding electrode on the insulating protection layer and the first expansion electrode, wherein the first welding electrode is electrically connected with the first expansion electrode through the first opening, manufacturing a second welding electrode on the insulating protection layer and the epitaxial structure, and the second welding electrode is electrically connected with the epitaxial structure through the second opening to form an initial chip; Bonding the initial chip to the temporary substrate by means of bonding; Removing the growth substrate by adopting a laser stripping mode; manufacturing a DBR reflecting layer under the epitaxial structure and the insulating protective layer; and removing the temporary substrate to form the Micro LED chip.
  10. 10. The method of claim 9, wherein providing an epitaxial wafer comprises: Providing an initial epitaxial wafer, wherein the initial epitaxial wafer comprises a growth substrate, a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are sequentially stacked from bottom to top; etching the initial epitaxial wafer, exposing the side surfaces of the second semiconductor layer and the light-emitting layer and the surface of the first semiconductor layer, and forming an intermediate epitaxial wafer; And continuing to etch the middle epitaxial wafer, and exposing the side surface of the first semiconductor layer and the surface of the growth substrate to form an epitaxial wafer.

Description

Micro LED chip and manufacturing method thereof Technical Field The invention relates to the technical field of semiconductors, in particular to a Micro LED chip and a manufacturing method thereof. Background A light emitting Diode (LIGHT EMITTING Diode, LED) is a semiconductor device capable of converting a current into light in a specific wavelength range, and its light emitting principle is that electrons move between an n-type semiconductor and a p-type semiconductor to have energy difference, and release energy in the form of light, so that the light emitting Diode is called a cold light source, and has advantages of low power consumption, small size, high brightness, easy matching with an integrated circuit, high reliability, and the like, and is widely used as a light source. Further, as LED technology is mature, technology of an LED display or a Micro LED (Micro light emitting diode) display directly using an LED as a self-luminous display dot pixel is also increasingly widely used. Micro LEDs, which are LED chips with a size of <50 μm, are considered to be the most likely replacement of OLEDs, and are the next generation of mainstream display technologies, and because of their small size, the pitch can be less than P0.5, and are widely used in devices and places where high brightness, ultra-high resolution, and high color saturation are required. Because the chip is smaller and the welding area is limited, the positive and negative welding electrodes of the chip are required to be as high as possible, but the current Micro LED chip mostly adopts a flip chip structure (the light emitting direction is deviated from the electrode direction) for stripping the growth substrate, and the requirement that the positive and negative welding electrodes are as high as possible cannot be met. Disclosure of Invention The invention aims to provide a Micro LED chip and a manufacturing method thereof, which adopt a forward chip structure with the light emitting direction being the same as the electrode direction, and lead the positive electrode and the negative electrode of the chip to be welded at the same height. In order to achieve the above object, the present invention provides the following solutions: A Micro LED chip, the chip comprising a DBR reflective layer, an epitaxial structure, a first current blocking layer, a second current blocking layer, a transparent conductive layer, a first extension electrode, a second extension electrode, an insulating protective layer, a first welding electrode, and a second welding electrode; The epitaxial structure is arranged on the DBR reflecting layer; The first current blocking layer and the second current blocking layer are arranged on the epitaxial structure and are positioned at two ends of the epitaxial structure; The transparent conductive layer is arranged on the first current blocking layer, the second current blocking layer and the epitaxial structure between the first current blocking layer and the second current blocking layer; the first expansion electrode and the second expansion electrode are arranged on the transparent conductive layer at intervals; The insulating protection layer covers the outer surface of the structure consisting of the epitaxial structure, the first current blocking layer, the second current blocking layer, the transparent conductive layer, the first expansion electrode and the second expansion electrode and is in contact with the upper surface of the DBR reflecting layer which is not in contact with the epitaxial structure; A first opening and a second opening are reserved on the insulating protective layer; the first welding electrode is arranged on the insulating protection layer and is electrically connected with the first expansion electrode through the first opening; the second welding electrode is arranged on the insulating protection layer and is electrically connected with the epitaxial structure through the second opening; The first current blocking layer, the first extension electrode, and the first welding electrode correspond to each other, and the second current blocking layer, the second extension electrode, and the second welding electrode correspond to each other in a projection direction of the DBR reflection layer. A method for manufacturing a Micro LED chip, the method comprising: the method comprises the steps of providing an epitaxial wafer, wherein the epitaxial wafer comprises a growth substrate and an epitaxial structure which are sequentially stacked from bottom to top; manufacturing a first current blocking layer and a second current blocking layer on the epitaxial structure; Manufacturing transparent conductive layers on the first current blocking layer, the second current blocking layer and the epitaxial structure; Manufacturing a first expansion electrode and a second expansion electrode on the transparent conductive layer; manufacturing insulating protection layers on the growth substrate, the epitaxial