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Method for manufacturing light emitting device

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Title: Method for manufacturing light emitting device.
Abstract: A method for manufacturing a light emitting device, includes: forming a first multilayer body including a first substrate, a first semiconductor layer provided on the first substrate and having a light emitting layer, and a first metal layer provided on the first semiconductor layer; forming a second multilayer body including a second substrate having a thermal expansion coefficient different from a thermal expansion coefficient of the first substrate, and a second metal layer provided on the second substrate; a first bonding step configured to heat the first metal layer and the second metal layer being in contact with each other; removing the first substrate after the first bonding step; and a second bonding step configured to perform, after the removing, heating at a temperature higher than a temperature of the first bonding step. ...


Browse recent Kabushiki Kaisha Toshiba patents - Tokyo, JP
Inventors: Yasuhiko Akaike, Ryo Saeki, Yoshinori Natsume
USPTO Applicaton #: #20120104446 - Class: 257 98 (USPTO) - 05/03/12 - Class 257 
Active Solid-state Devices (e.g., Transistors, Solid-state Diodes) > Incoherent Light Emitter Structure >With Reflector, Opaque Mask, Or Optical Element (e.g., Lens, Optical Fiber, Index Of Refraction Matching Layer, Luminescent Material Layer, Filter) Integral With Device Or Device Enclosure Or Package

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The Patent Description & Claims data below is from USPTO Patent Application 20120104446, Method for manufacturing light emitting device.

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CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Division of application Ser. No. 12/544,353 filed Aug. 20, 2009; the entire contents of which are incorporated herein by reference.

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-028908, filed on Feb. 10, 2009; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for manufacturing a light emitting device.

2. Background Art

Semiconductor light emitting devices capable of emitting visible light including blue to red light can be widely used in such applications as illumination lamps, displays, and traffic signals. Such light emitting devices with high brightness can find wider application in light sources replacing fluorescent lamps and incandescent bulbs. Furthermore, reduction of operating current facilitates achieving low power consumption.

Here, in a light emitting device which uses a substrate made of e.g. GaAs having a bandgap wavelength of generally 870 nm, visible light emitted from the light emitting device and having emission wavelengths of 700 nm or less is absorbed by the substrate, causing the problem of decreased brightness.

If the substrate is made of e.g. GaP having a bandgap wavelength of generally 550 nm, optical absorption by the substrate can be reduced for visible light having longer wavelengths, which facilitates increasing the brightness. However, the lattice constant of InGaAlP-based semiconductors capable of emitting visible light in the wavelength range from yellow-green to red differs from the lattice constant of GaP by as large as several %, which makes it difficult to directly form an InGaAlP-based light emitting layer with low crystal defect density on a GaP substrate.

JP-A 2005-019424 (Kokai) discloses a technique related to a method for manufacturing a light emitting device by wafer bonding. In this technique, a substrate and a light emitting layer section are bonded via a metal layer. Here, a diffusion blocking semiconductor layer is provided to prevent metal diffusion from the metal layer into the light emitting layer, thereby preventing decrease in light emission characteristics.

However, it is difficult to achieve good wafer bonding characteristics while preventing cracking of the substrate in the heat treatment step for substrate lamination.

SUMMARY

OF THE INVENTION

According to an aspect of the invention, there is provided a method for manufacturing a light emitting device, including: forming a first multilayer body including a first substrate, a first semiconductor layer provided on the first substrate and having a light emitting layer, and a first metal layer provided on the first semiconductor layer; forming a second multilayer body including a second substrate having a thermal expansion coefficient different from a thermal expansion coefficient of the first substrate, and a second metal layer provided on the second substrate; a first bonding step configured to heat the first metal layer and the second metal layer being in contact with each other; removing the first substrate after the first bonding step; and a second bonding step configured to perform, after the removing, heating at a temperature higher than a temperature of the first bonding step.

According to an aspect of the invention, there is provided a method for manufacturing a light emitting device, including: forming a first multilayer body including a first substrate made of one of GaAs, GaP, and SiC, a first semiconductor layer provided on the first substrate and having a light emitting layer, and a first metal layer provided on the first semiconductor layer; forming a second multilayer body including a second substrate having a thermal expansion coefficient different from a thermal expansion coefficient of the first substrate and made of one of Si, Ge, and SiC, and a second metal layer provided on the second substrate; a first bonding step configured to heat the first metal layer and the second metal layer being in contact with each other; removing the first substrate after the first bonding step; and a second bonding step configured to perform, after the removing, heating at a temperature higher than a temperature of the first bonding step.

According to an aspect of the invention, there is provided a method for manufacturing a light emitting device, including: forming a first multilayer body including a first substrate made of sapphire, a first semiconductor layer provided on the first substrate and having a light emitting layer, and a first metal layer provided on the first semiconductor layer; forming a second multilayer body including a second substrate having a thermal expansion coefficient different from a thermal expansion coefficient of the first substrate and made of one of Si, Ge, and SiC, and a second metal layer provided on the second substrate; a first bonding step configured to heat the first metal layer and the second metal layer being in contact with each other; removing the first substrate after the first bonding step; and a second bonding step configured to perform, after the removing, heating at a temperature higher than a temperature of the first bonding step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a light emitting device according to a first embodiment;

FIGS. 2A to 2D are process cross-sectional views of a method for manufacturing the light emitting device according to the first embodiment;

FIGS. 3A to 3D are process cross-sectional views of a method for manufacturing a light emitting device according to a comparative example;

FIGS. 4A to 4D are process cross-sectional views showing a method for manufacturing a light emitting device according to a second embodiment

FIGS. 5A to 5D are process cross-sectional views of a light emitting device according to a variation of the second embodiment;

FIG. 6 is a schematic cross-sectional view of a light emitting device according to a third embodiment;



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Light-emitting device
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Method of manufacturing color filter substrate, semi-transmissive liquid crystal display using the same, and manufacturing method thereof
Industry Class:
Active solid-state devices (e.g., transistors, solid-state diodes)
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stats Patent Info
Application #
US 20120104446 A1
Publish Date
05/03/2012
Document #
13343810
File Date
01/05/2012
USPTO Class
257 98
Other USPTO Classes
257103, 257E33066
International Class
01L33/60
Drawings
9



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