# US 7,465,592 B2 · Method of making vertical structure semiconductor devices including forming hard and soft copper layers

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- Number: US 7,465,592 B2
- Document ID: US7465592B2
- Status: Granted
- Kind: B2
- Application number: 11/117,084
- Filed: 2005-04-27
- Published: 2005-11-03
- Granted: 2008-12-16
- Earliest claimed: 2004-04-28
- Assignees: Verticle, Inc.
- Inventors: Myung Cheol Yoo
- Web page: https://patentgrep.com/patent/US7465592B2

## CPC

- H10H 20/018: {Bonding of wafers}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H 20/841: Reflective coatings, e.g. dielectric Bragg reflectors
- H10P 34/42: with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20)
- H10W 72/07521: {Aligning}
- H10W 72/536: {the connected ends being ball-shaped}
- H10W 72/5522: {comprising gold [Au]}
- H10W 72/884: {Die-attach connectors and bond wires}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

The invention provides a reliable way to fabricate a new vertical structure compound semiconductor device with improved light output and a laser lift-off processes for mass production of GaN-based compound semiconductor devices. A theme of the invention is employing direct metal support substrate deposition prior to the LLO by an electro-plating method to form an n-side top vertical structure. In addition, an ITO DBR layer is employed right next to a p-contact layer to enhance the light output by higher reflectivity. A perforated metal wafer carrier is also used for wafer bonding for easy handling and de-bonding. A new fabrication process is more reliable compared to the conventional LLO-based vertical device fabrication. Light output of the new vertical device having n-side up structure is increased 2 or 3 times higher than that of the lateral device fabricated with same GaN/InGaN epitaxial films.

## Claims

### Claim 1

A method of fabricating semiconductor devices, comprising the steps of:
forming a plurality of semiconductor layers over an insulated substrate, at least one of said plurality of semiconductor layers comprises GaN;
forming a plurality of metal support layers deposited using electroplating including a copper layer plated using cyanide or acid-base bath and a sulfate-base copper alloy layer over a first side of said plurality of semiconductor layers;
removing said insulated substrate from said plurality of semiconductor layers;
forming one or more electrical contacts, after said insulated substrate was removed, over a second side of said plurality of semiconductor layers wherein said second side is opposite said first side; and
separating said plurality of semiconductor layers into a plurality of individual semiconductor devices.

### Claim 2 (depends on 1)

The method of claim 1, further comprising the step of:
forming a buffer layer between said plurality of semiconductor layers and said insulated substrate.

### Claim 3 (depends on 1)

The method of claim 1, wherein;
said removing includes applying a laser beam to an interface between said plurality of semiconductor layers and said insulated substrate, and inserting a diffusing media between a laser source that produces said laser beam and said insulated substrate for uniform laser beam energy distribution.

### Claim 4 (depends on 1)

The method of claim 1, further comprising the step of:
attaching a perforated wafer carrier to said plurality of metal support layers.

### Claim 5 (depends on 2)

The method of claim 2, further comprising the step of:
attaching a perforated wafer carrier to said plurality of metal support layers.

### Claim 6 (depends on 3)

The method of claim 3, further comprising the step of:
attaching a perforated wafer carrier to said plurality of metal support layers.

### Claim 7 (depends on 2)

The method of claim 2, wherein:
said separating includes forming a trench between two devices of said plurality of individual semiconductor devices, passivating exposed portions of said plurality of individual semiconductor devices, and transferring said plurality of individual semiconductor devices to a support film.

### Claim 8 (depends on 2)

The method of claim 2, further comprising the step of:
assembling at least one of said plurality of individual semiconductor devices to a lead frame using a one-step die bonding and wire bonding technique.

### Claim 9 (depends on 7)

The method of claim 7, further comprising the step of:
assembling at least one of said plurality of individual semiconductor devices to a lead frame using a one-step die bonding and wire bonding technique.

### Claim 10

A method of fabricating a light emitting semiconductor device, comprising the steps of:
forming a diode structure over a substrate;
forming a plurality of metal layers over a first side of said diode structure;
forming an Indium Tin Oxide (ITO) layer including a copper layer plated using cyanide or acid-base bath and a sulfate-base copper alloy layer over said diode structure;
removing said substrate from said diode structure;
forming one or more contacts over a second side of said diode structure where said substrate was removed, said second side being opposite said first side; and
separating said diode structure into a plurality of individual diodes wherein said removing includes applying a laser beam to an interface between said diode structure and said substrate, inserting diffusing media between a laser source that produces said laser beam and said substrate, and liquefying at least a portion of a first buffer layer formed over said substrate.

### Claim 11 (depends on 10)

The method of claim 10, wherein the said forming the said diode structure comprises the steps of:
depositing said first buffer layer including one of CaN and AlN over said substrate; and
depositing a n-GaN layer over said first buffer layer.

### Claim 12 (depends on 10)

The method of claim 10, wherein said forming said diode structure comprises the steps of:
depositing said first buffer layer including one of GaN and AlN over said substrate;
depositing a second buffer layer including AlGaN over said substrate; and
depositing a n-GaN layer over said second buffer layer.

### Claim 13 (depends on 10)

The method of claim 10, wherein:
said separating includes forming a trench between two diodes of said plurality of individual diodes, passivating exposed portions of said plurality of individual diodes, and transferring said plurality of individual diodes to a support film.

### Claim 14 (depends on 10)

The method of claim 10, further comprising the step of:
attaching a wafer carrier to said plurality of metal layers.

### Claim 15

A method of fabricating semiconducter devices, comprising:
forming a GaN-containing layer over a substrate;
forming a p-type ITO layer, said p-type ITO layer being disposed toward a first side of said GaN-containing layer;
forming a metal support layer, said metal support layer being disposed toward said first side of said GaN-containing layer, said metal support layer being deposited using electroplating including a copper layer plated using cyanide or acid-base bath and a sulfate-base copper alloy layer, wherein said p-type ITO layer is disposed between said GaN-containing layer and said metal support layer;
removing said substrate front said GaN-containing layer;
forming one or more electrical contacts, after said substrate was removed, toward a second side of said GaN-containing layer, wherein said second side is opposite said first side.

### Claim 16 (depends on 15)

The method of claim 15, further comprising forming a buffer layer between said GaN-containing layer and said substrate.

### Claim 17 (depends on 15)

The method of claim 15, wherein said removing includes applying a laser beam to an interface between said GaN-containing layer and said substrate, and inserting a diffusing media between a laser source that produces said laser beam and said substrate for uniform laser beam energy distribution.

### Claim 18 (depends on 15)

The method of claim 15 further comprising forming a plurality of individual devices by creating trenches between at least two of said electrical contacts and passivating exposed portions of said plurality of individual devices after said creating.

### Claim 19 (depends on 18)

The method of claim 18, further comprising assembling at least one of said plurality of individual devices to a lead frame using a one-step die bonding and wire bonding technique.

### Claim 20 (depends on 15)

The method of claim 15 wherein said one or more electrical contacts includes n-contacts.

### Claim 21 (depends on 15)

The method of claim 15 wherein said one or more electrical contacts includes n-ITO contacts.