METHOD FOR MANUFACTURING LIGHT EMITTING DEVICE

• US 20100203659A1
• Filed: 08/20/2009
• Published: 08/12/2010
• Est. Priority Date: 02/10/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: NATSUME, Yoshinori, SAEKI, Ryo, AKAIKE, Yasuhiko
• Granted Patent: US 8,110,451 B2
• Time in Patent Office: Days
• US Class Current: 438/29
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate

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.

Claims

1. A method for manufacturing a light emitting device, comprising:

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.

2. The method according to claim 1, wherein

the first metal layer includes a first metal film having a first melting point and a second metal film having a second melting point different from the first melting point, and

the second melting point of the second metal film provided between the first metal film provided adjacent to the first semiconductor layer and the second metal layer is lower than both the first melting point and a melting point of the second metal layer.

3. A method for manufacturing a light emitting device, comprising:

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.

4. The method according to claim 3, wherein the second bonding step includes forming a first electrode on the first semiconductor layer and forming a second electrode on the second substrate, followed by heating at the temperature higher than the temperature of the first bonding step.

5. The method according to claim 4, wherein the temperature in the second bonding step allows ohmic contact to be formed between the first semiconductor layer and the first electrode, and between the second substrate and the second electrode, respectively.

6. The method according to claim 3, wherein the removing includes using at least one of mechanical polishing method and wet etching method.

7. The method according to claim 3, wherein

the first metal layer includes a first Au film at its surface, and

the second metal layer includes a second Au film at its surface.

8. The method according to claim 7, wherein the first metal layer further includes a first Ti film provided adjacent to the first semiconductor layer and a first Pt film provided between the first Ti film and the first Au film, or further includes an Ni film provided between the first semiconductor layer and the first Au film.

9. The method according to claim 7, wherein the second metal layer further includes a second Ti film provided adjacent to the second substrate and a second Pt film provided between the second Ti film and the second Au film.

10. The method according to claim 3, wherein

at least one of the first metal layer and the second metal layer includes a solder layer,

the temperature of the first bonding step is lower than a melting point of the solder layer, and

the temperature of the second bonding step is equal to or higher than the melting point of the solder layer.

11. The method according to claim 10, wherein the solder layer includes at least one of AuSn, AuGe, AuSi, and In.

12. A method for manufacturing a light emitting device, comprising:

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.

13. The method according to claim 12, wherein the forming the first multilayer body includes forming the first semiconductor layer represented by a composition formula In_xGa_yAl₁₋

x−

yN (0≦

x≦

1, 0≦

y≦

1, x+y≦

1).

14. The method according to claim 13, wherein the removing includes using at least one of laser lift-off method and mechanical polishing method.

15. The method according to claim 12, wherein the forming the first multilayer body includes forming a transparent electrode between the first semiconductor layer and the first metal layer.

16. The method according to claim 12, wherein

the first metal layer includes a first Au film at its surface, and

the second metal layer includes a second Au film at its surface.

17. The method according to claim 16, wherein the first metal layer further includes a first Ti film provided adjacent to the first semiconductor layer and a first Pt film provided between the first Ti film and the first Au film, or includes an Ni film provided between the first semiconductor layer and the first Au film.

18. The method according to claim 16, wherein the second metal layer further includes a second Ti film provided adjacent to the second substrate and a second Pt film provided between the second Ti film and the second Au film.

19. The method according to claim 12, wherein

at least one of the first metal layer and the second metal layer includes a solder layer,

the temperature of the first bonding step is lower than a melting point of the solder layer, and

the temperature of the second bonding step is equal to or higher than the melting point of the solder layer.

20. The method according to claim 19, wherein the solder layer includes at least one of AuSn, AuGe, AuSi, and In.