Flip-chip LED, method for manufacturing the same and flip-chip package of the same

• US 9,559,265 B2
• Filed: 03/20/2015
• Issued: 01/31/2017
• Est. Priority Date: 03/21/2014
• Status: Active Grant

• Current Assignee: Top Bumping Semiconductor Company Limited
• Original Assignee: Mao Bang Electronic Co., Ltd.
• Inventors: Chyu, Christopher, Sung, Ta-Lun, Lai, Tung-Sheng
• Primary Examiner(s): Patel, Reema
• Application Number:
  US14/664,037
• Publication Number:
  US 20150270448A1
• Time in Patent Office: 683 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/81 using a bump connector
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/486 adapted for surface mounting

Abstract

A flip-chip LED, a method for manufacturing the same and a flip-chip LED package are revealed. The LED includes at least one multi-layer reflective layer covered over the outermost layer thereof. The multi-layer reflective layer includes non-conductive reflective layer or combination of the non-conductive reflective layer with conductive reflective layer. The multi-layer reflective layer is manufactured by physical vapor deposition (PVD) with a mask at one time. The mask is used to form a pattern of the multi-layer reflective layer. Thus a photoresist layer is further formed on surface of exposed electrodes. Then a pumping and venting process is used only once during to complete vacuum deposition of each layer of the multi-layer reflective layer in turn.

Claims

1. A flip-chip LED comprising:

a sapphire substrate;

an N-type ohmic contact layer formed and disposed on the substrate;

a P-type ohmic contact layer formed and arranged at the N-type ohmic contact layer;

a light emitting layer formed at an interface between the N-type ohmic contact layer and the P-type ohmic contact layer;

a transparent conductive metal oxide layer formed and set on the P-type ohmic contact layer;

two exposed electrodes with different polarities including a negative electrode and a positive electrode; and

a multi-layer reflective layer covered over an outermost layer thereof;

wherein the multi-layer reflective layer is manufactured by Physical Vapor Deposition (PVD) with a mask at one time to form each layer of the multi-layer reflective layer in turn on an outer surface of the flip-chip LED except the outer surface disposed with the exposed electrodes;

wherein the mask is used to form a pattern of the multi-layer reflective layer so that a photoresist layer is disposed on surface of each of the two exposed electrodes with different polarities;

then a pumping and venting process is used only once to form each layer of the multi-layer reflective layer in turn, and

wherein the multi-layer reflective layer is formed by a non-conductive silicon dioxide (SiO2) film, a conductive aluminum film and a non-conductive silicon dioxide (SiO2) film;

the conductive aluminum film is formed between the two non-conductive silicon dioxide (SiO2) films.

2. The flip-chip LED as claimed in claim 1, wherein the multi-layer reflective layer is disposed with an electrode division area by which the multi-layer reflective layer is divided into two separate half reflective layers that are electrically insulated from each other and electrically connected the two exposed electrodes with different polarities respectively.

3. The flip-chip LED as claimed in claim 1, wherein the multi-layer reflective layer is formed by non-conductive distributed Bragg reflector (DBR).

4. The flip-chip LED as claimed in claim 1, wherein a conductive reflective layer is disposed over the multi-layer reflective layer;

the conductive reflective layer is formed on an outer surface of the multi-layer reflective layer by physical vapor deposition (PVD) with the same mask at one time.

5. The flip-chip LED as claimed in claim 4, wherein the conductive reflective layer is a metal reflective layer formed by an aluminum film, a silver film or combinations of the aluminum film with the silver film.

6. A flip-chip LED package comprising:

a flip-chip LED chip; and

a heat spreader;

wherein the LED chip includes a sapphire substrate, an N-type ohmic contact layer, a light emitting layer, a P-type ohmic contact layer, a transparent conductive metal oxide layer, two exposed electrodes with different polarities, and a multi-layer reflective layer covered over the outermost layer thereof;

wherein the multi-layer reflective layer is manufactured by Physical Vapor Deposition (PVD) with a mask at one time and is formed on an outer surface of the flip-chip LED except the outer surface disposed with the exposed electrodes;

wherein the mask is used to form a pattern of the multi-layer reflective layer so that a photoresist layer is disposed on surface of each of the two exposed electrodes with different polarities;

then a pumping and venting process is used only once to form each layer of the multi-layer reflective layer in turn;

wherein the LED chip is aligned and mounted to contacts on the heat spreader with conductive adhesive in an upside-down manner by die bonding and reflow soldering, and

wherein the multi-layer reflective layer is formed by a non-conductive silicon dioxide (SiO2) film, a conductive aluminum film and a non-conductive silicon dioxide (SiO2) film;

the conductive aluminum film is formed between the two non-conductive silicon dioxide (SiO2) films.

7. The flip-chip LED package as claimed in claim 6, wherein a conductive reflective layer is disposed over the multi-layer reflective layer;

the conductive reflective layer is formed on an outer surface of the multi-layer reflective layer by physical vapor deposition (PVD) with the same mask at one time.

8. The flip-chip LED package as claimed in claim 7, wherein the conductive reflective layer is a metal reflective layer formed by an aluminum film, a silver film or combinations of the aluminum film with the silver film.