Method for forming a semiconductor device having a metal substrate

• US 6,555,405 B2
• Filed: 08/21/2001
• Issued: 04/29/2003
• Est. Priority Date: 03/22/2001
• Status: Expired due to Fees

• Current Assignee: Unit Light Technology Incorporated
• Original Assignee: Unit Light Technology Incorporated
• Inventors: Chen, Nai-Chuan, Tzou, Yuan-Hsin, Chen, Chien-An, Yih, Nae-Guann, Wu, Bor-Jen
• Primary Examiner(s): Mulpuri, Savitri
• Application Number:
  US09/933,642
• Publication Number:
  US 20020137244A1
• Time in Patent Office: 616 Days
• Field of Search: 438/22, 438/24, 438/29, 438/33, 438/46, 438/455, 438/458, 438/459, 438/977, 438/464
• US Class Current: 438/22
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2933/0075 relating to heat extraction or cooling elements
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: Y10S 438/977 Thinning or removal of substrate

Abstract

The present invention provides a method for forming a semiconductor device with a metal substrate. The method includes providing at least one semiconductor substrate; forming at least one semiconductor layer on the semiconductor substrate; forming the metal substrate on the semiconductor substrate and then removing the semiconductor substrate. The metal substrate has advantages of high thermal and electrical conductivity that can improve the reliability and lifetime of the semiconductor device.

Claims

1. A method for forming a light emitting diode with a metal substrate, said method comprising:

providing a semiconductor substrate;

forming an epitaxial layer on said semiconductor substrate, said epitaxial layer consisting of a plurality of semiconductor layers for forming light emitting diode;

forming a metal ohmic electrode layer on said epitaxial layer;

forming said metal substrate on said metal ohmic electrode layer;

removing said semiconductor substrate; and

forming a ohmic electrode bonding pad on said epitaxial layer.

2. The method according to claim 1, wherein said metal substrate is formed by the evaporation of a metal material, and said metal material is selected from the groups of Au, Pt, Pd, Zn, Al, Ni, Ti, Cr, single layer and alloys of the above, or multiple layers and alloys of the above.

3. The method according to claim 1, wherein said metal substrate is formed by the sputtering of a metal material, and said metal material is selected from the groups of Au, Pt, Pd, Zn, Al, Ni, Ti, Cr, single layer and alloys of the above, or multiple layers and alloys of the above.

4. The method according to claim 1, wherein said metal substrate is formed by fusing at least a cold-forming metal that subsequently is cast on said semiconductor layer, and said cold-forming metal is selected from the groups of In, Pb, Sn, single layer and alloys of the above, or multiple layers and alloys of the above.

5. The method according to claim 1, wherein said metal substrate is formed by fusing at least a cold-forming metal material with at least one other metal materials.

6. The method according to claim 1, wherein said metal substrate is formed by the electroplating of a metal material, and said metal material is selected from the groups of Cu, Ni, Cr, Zn, Sn, Ag, Au, single layer and alloys of the above, or multiple layers and alloys of the above.

7. The method according to claim 1, wherein said metal substrate is formed by the electrodeless electroplating of a metal material, and said metal material is selected from the groups of Cu, Ni, Au, Pt, Pd, single layer and alloys of the above, or multiple layers and alloys of the above.

8. The method according to claim 1 further comprising forming a distributed Bragg reflector between said epitaxial layer and said metal ohmic electrode layer, thereby enhances reflection and further enhances efficiency of light emitting.

9. The method according to claim 1 further comprising forming a non-absorbing layer covering whole or portion of a wafer between said epitaxial layer and said metal ohmic electrode layer, which has a refracting index smaller than that of said epitaxial layer and thereby enhances reflectivity and further enhances efficiency of light emitting, said non-absorbing layer is selected from the groups of In₂O₃, SnO₂, ITO, HfO₂, MgO, SiO(SiO₂□

SiO_x), TiO(TiO₂,TiO_x, Ti₂O₃, Ti₂O₅), ZnO, ZnS, Al₂O₃Ta₂O₃, and Ta₂O₅.

10. The method according to claim 1 further comprising forming a rough layer between said epitaxial layer and said metal ohmic electrode layer, thereby enhances upward reflection and further enhances efficiency of light emitting.

11. The method according to claim 1 further comprising locally forming a semi-insulating layer between said epitaxial layer and said metal ohmic electrode layer during the formation of said epitaxial layer, said semi-insulating layer positioned right above said ohmic electrode bonding pad and thereby blocks directly downward current and further enhances efficiency of light emitting.

12. The method according to claim 1 further comprising locally forming a semiconductor layer with a second conduction type between said epitaxial layer and said metal ohmic electrode layer during the formation of said epitaxial layer, said semiconductor layer with a second conduction type positioned right above said ohmic electrode bonding pad and thereby blocks directly downward current and further enhances efficiency of light emitting.

13. The method according to claim 1 further comprising locally forming a semi-insulating layer between said epitaxial layer and said metal ohmic electrode layer by the method of ion implantation, said semi-insulating layer positioned right above said ohmic electrode bonding pad and thereby blocks directly downward current and further enhances efficiency of light emitting.

14. The method according to claim 1 further comprising locally forming an insulating layer between said epitaxial layer and said metal ohmic electrode layer, said insulating layer positioned right above said ohmic electrode bonding pad and thereby blocks directly downward current and further enhances efficiency of light emitting.

15. The method according to claim 1 further comprising locally forming a non-ohmic contact metal region between said epitaxial layer and said metal ohmic electrode layer, said non-ohmic contact metal region positioned right above said ohmic electrode bonding pad and thereby blocks directly downward current and further enhances efficiency of light emitting.