A kind of preparation method of high-brightness flip-chip ultraviolet LED chip

Abstract

The invention provides a method for manufacturing high-brightness flip ultraviolet LED chips. The method has the advantages that the external quantum efficiency of the ultraviolet LED chips and the brightness of the chips can be improved, and contact voltages of the chips can be reduced; Ni / Ag / Al combined reflecting mirrors with high ultraviolet reflectance replace the traditional thick Ag reflecting mirrors, accordingly, the high-brightness flip ultraviolet LED chips are high in ultraviolet reflectance, and reflecting effects of the high-brightness flip ultraviolet LED chips are superior to reflecting effects of the Ag reflecting mirrors in deep ultraviolet regions; ultra-thin Ni / Ag of the high-brightness ultraviolet LED chips can be in ohmic contact with type-P gallium nitride after the ultra-thin Ni / Ag are annealed, accordingly, the contact voltages of the flip chips can be reduced, ultraviolet absorption can be reduced as compared with the traditional thick Ag reflecting mirrors, and the brightness of the chips can be improved.

Description

technical field

[0001] The invention belongs to the technical field of LED chip preparation, and mainly relates to a method for preparing a high-brightness flip-chip ultraviolet LED chip. Background technique

[0002] With the development of LED applications, UV LEDs are widely used because of their wider spectral range (light emitting wavelengths can cover the 210-400nm band), more energy-saving, and no toxic mercury. In many aspects of life, such as UV disinfection, UV hardening, optical sensors, UV authentication, body fluid detection and analysis and other fields. At present, the technical bottleneck of ultraviolet LED is mainly low efficiency. For chips with a wavelength lower than 365nm, the output power of the UV LED is only 5%-8% of the input power; when the wavelength is above 385nm, the efficiency of the UV LED is improved, but only 15% of the input power.

[0003] Flip-chip LED chips can effectively improve the brightness of LED chips. The traditional flip-chip...

Examples

Embodiment 1

[0029] figure 1 It is a structural diagram of a flip-chip ultraviolet LED chip of the present invention, and its manufacturing process is as follows figure 2 Shown: Using ICP etching technology for low-damage ultraviolet gallium nitride etching, using evaporation technology for high reflectivity P-type ohmic contact Ni / Ag / Al thin film preparation and P, N binding electrode Au / Sn film Layer preparation, using PECVD to deposit a silicon dioxide insulating layer and using BOE to etch it to form P and N electrode through holes.

[0030] The best embodiment of preparation technology is given below:

[0031] 1. Use aqua regia (HNO 3 : HCl=1:3) for surface treatment for 10 minutes, rinse with deionized water and dry;

[0032] 2. Put it into the ICP equipment for low-damage ultraviolet gallium nitride etching technology. The P-type gallium nitride layer and the underlying multi-quantum well light-emitting layer in the epitaxial wafer are etched to expose the N-type gallium nitride...

Embodiment 2

[0043] The thin film evaporation machine performs Ni / Ag thin film evaporation, and the Ni evaporation rate is Evaporation thickness The Ag evaporation rate is Evaporation thickness When evaporating, the vacuum degree is higher than 2.0×10-6Torr; the annealing temperature is 400°C, and the annealing time is 8 minutes; the thin film evaporation machine performs Al thin film evaporation, and the evaporation rate is Evaporation thickness The rest of the processes are the same as those in the first embodiment, and a high-brightness flip-chip ultraviolet LED chip can be prepared, which can be directly welded by eutectic soldering technology.

Embodiment 3

[0045] The thin film evaporation machine performs Ni / Ag thin film evaporation, and the Ni evaporation rate is Evaporation thickness The Ag evaporation rate is Evaporation thickness When evaporating, the vacuum degree is higher than 2.0×10-6Torr; nitrogen protection annealing, annealing temperature 410 ℃, annealing time 10min; thin film evaporation machine for Al thin film evaporation, evaporation rate is Evaporation thickness The rest of the processes are the same as those in the first embodiment, and a high-brightness flip-chip ultraviolet LED chip can be prepared, which can be directly welded by eutectic soldering technology.

[0046] 40*40mil prepared using the scheme of the present invention 2 The ultraviolet LED chip with a peak wavelength of 375nm has an optical power of 90mw and a voltage of 3.5V; the chip with a peak wavelength of 385nm has an optical power of 155mw and a voltage of 3.3V; the chip with a peak wavelength of 400nm has an optical power of 250mw ...

technical field

[0001] The invention belongs to the technical field of LED chip preparation, and mainly relates to a method for preparing a high-brightness flip-chip ultraviolet LED chip. Background technique

[0002] With the development of LED applications, UV LEDs are widely used because of their wider spectral range (light emitting wavelengths can cover the 210-400nm band), more energy-saving, and no toxic mercury. In many aspects of life, such as UV disinfection, UV hardening, optical sensors, UV authentication, body fluid detection and analysis and other fields. At present, the technical bottleneck of ultraviolet LED is mainly low efficiency. For chips with a wavelength lower than 365nm, the output power of the UV LED is only 5%-8% of the input power; when the wavelength is above 385nm, the efficiency of the UV LED is improved, but only 15% of the input power.

[0003] Flip-chip LED chips can effectively improve the brightness of LED chips. The traditional flip-chip...

Examples

Embodiment 1

[0029] figure 1 It is a structural diagram of a flip-chip ultraviolet LED chip of the present invention, and its manufacturing process is as follows figure 2 Shown: Using ICP etching technology for low-damage ultraviolet gallium nitride etching, using evaporation technology for high reflectivity P-type ohmic contact Ni / Ag / Al thin film preparation and P, N binding electrode Au / Sn film Layer preparation, using PECVD to deposit a silicon dioxide insulating layer and using BOE to etch it to form P and N electrode through holes.

[0030] The best embodiment of preparation technology is given below:

[0031] 1. Use aqua regia (HNO 3 : HCl=1:3) for surface treatment for 10 minutes, rinse with deionized water and dry;

[0032] 2. Put it into the ICP equipment for low-damage ultraviolet gallium nitride etching technology. The P-type gallium nitride layer and the underlying multi-quantum well light-emitting layer in the epitaxial wafer are etched to expose the N-type gallium nitride...

Embodiment 2

[0043] The thin film evaporation machine performs Ni / Ag thin film evaporation, and the Ni evaporation rate is Evaporation thickness The Ag evaporation rate is Evaporation thickness When evaporating, the vacuum degree is higher than 2.0×10-6Torr; the annealing temperature is 400°C, and the annealing time is 8 minutes; the thin film evaporation machine performs Al thin film evaporation, and the evaporation rate is Evaporation thickness The rest of the processes are the same as those in the first embodiment, and a high-brightness flip-chip ultraviolet LED chip can be prepared, which can be directly welded by eutectic soldering technology.

Embodiment 3

[0045] The thin film evaporation machine performs Ni / Ag thin film evaporation, and the Ni evaporation rate is Evaporation thickness The Ag evaporation rate is Evaporation thickness When evaporating, the vacuum degree is higher than 2.0×10-6Torr; nitrogen protection annealing, annealing temperature 410 ℃, annealing time 10min; thin film evaporation machine for Al thin film evaporation, evaporation rate is Evaporation thickness The rest of the processes are the same as those in the first embodiment, and a high-brightness flip-chip ultraviolet LED chip can be prepared, which can be directly welded by eutectic soldering technology.

[0046] 40*40mil prepared using the scheme of the present invention 2 The ultraviolet LED chip with a peak wavelength of 375nm has an optical power of 90mw and a voltage of 3.5V; the chip with a peak wavelength of 385nm has an optical power of 155mw and a voltage of 3.3V; the chip with a peak wavelength of 400nm has an optical power of 250mw ...

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