LED chip with improved bonding strength and LED module using the LED chip

• US 10,644,212 B2
• Filed: 08/22/2018
• Issued: 05/05/2020
• Est. Priority Date: 11/27/2017
• Status: Active Grant

• Current Assignee: Lumens Co., Ltd.
• Original Assignee: Lumens Co., Ltd.
• Inventors: Kim, Daewon, Won, Yelim
• Primary Examiner(s): Ojeh, Nduka E
• Application Number:
  US16/108,158
• Publication Number:
  US 20190165230A1
• Time in Patent Office: 622 Days
• CPC Class Codes: H01L 24/14 of a plurality of bump connectors
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

An LED module is disclosed. The LED module includes: a mount substrate including electrodes; an LED chip including a semiconductor stacked structure, a passivation layer covering the outer surface of the semiconductor stacked structure, and electrode pads connected to the outer surface of the semiconductor stacked structure through openings formed in the passivation layer; and solder bumps connecting the electrode pads to the corresponding electrodes and formed using a solder material represented by Sn-M (where M is a metal).

Claims

1. An LED chip comprising:

a semiconductor stacked structure comprising a first conductive semiconductor layer and an active layer and a second conductive semiconductor layer sequentially formed on one area of the first conductive semiconductor layer;

a passivation layer covering the outer surface of the semiconductor stacked structure and comprising a first opening and a second opening;

a first electrode pad connected to the first conductive semiconductor layer through the first opening; and

a second electrode pad connected to the second conductive semiconductor layer through the second opening,

wherein each of the first electrode pad and the second electrode pad comprises a multilayer body comprising a plurality of metal layers and a contact body connected to the multilayer body, the contact body of the first electrode pad comprises a surface contact part in contact with the passivation layer outside the first opening and an ohmic contact part in contact with the first conductive semiconductor layer through the first opening, the contact body of the second electrode pad comprises a surface contact part in contact with the passivation layer outside the second opening and an ohmic contact part in contact with the second conductive semiconductor layer through the second opening, each of the ohmic contact parts comprises an ohmic contact layer in direct contact with the first or second conductive semiconductor layer and comprising Au and one or more metal layers formed on the ohmic contact layer and interposed between the ohmic contact layer and the surface contact part, and a ratio of an area of the first or second opening to a surface area of the ohmic contact layer is from 0.1;

1 to 0.3;

1.

2. The LED chip according to claim 1, wherein the multilayer body comprises a structure consisting of different metal layers stacked alternately on one another.

3. The LED chip according to claim 1, wherein the surface contact part comprises a common contact metal layer in contact with the passivation layer and the ohmic contact part.

4. The LED chip according to claim 3, wherein a height of the contact interface between the common contact metal layer and the passivation layer is different from that of the contact interface between the common contact metal layer and the ohmic contact part.

5. The LED chip according to claim 1, wherein the area of the first opening is larger than that of the second opening.

6. The LED chip according to claim 1, wherein an Au end layer is formed in the multilayer body.

7. The LED chip according to claim 6, wherein the Au end layer has a thickness of less than 1500 Å

and the total thickness of Au layers, comprising the Au end layer, is less than 15% of the thickness of the multilayer body.

8. The LED chip according to claim 1, wherein the multilayer body comprises a metal stacked structure formed by stacking two or more metals selected from the group consisting of Pt, Cr, Al, Ni, Ti, Au, Cu, Mo, W and Au.

9. An LED chip comprising:

a semiconductor stacked structure comprising a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;

a passivation layer comprising an opening through which a portion of the lower surface of the semiconductor stacked structure is exposed;

an upper electrode pad connected to the upper surface of the semiconductor stacked structure; and

a lower electrode pad connected to the lower surface of the semiconductor stacked structure through the opening,

wherein the lower electrode pad comprises a multilayer body comprising a plurality of metal layers and a contact body connected to the multilayer body, the contact body comprises a surface contact part in contact with the passivation layer outside the opening and an ohmic contact part in contact with the first or second conductive semiconductor layer through the opening, the ohmic contact part comprises an ohmic contact layer in direct contact with the first or second conductive semiconductor layer and comprising Au and one or more metal layers formed on the ohmic contact layer and interposed between the ohmic contact layer and the surface contact part, and a ratio of an area of the opening to a surface area of the ohmic contact layer is from 0.1;

1 to 0.3;

1.

10. The LED chip according to claim 9, wherein the multilayer body comprises a structure consisting of different metal layers stacked alternately on one another.

11. The LED chip according to claim 9, wherein the surface contact part comprises a common contact metal layer in contact with the passivation layer and the ohmic contact part.

12. The LED chip according to claim 11, wherein a height of the contact interface between the common contact metal layer and the passivation layer is different from that of the contact interface between the common contact metal layer and the ohmic contact part.

13. The LED chip according to claim 9, wherein an Au end layer is formed in the multilayer body.

14. The LED chip according to claim 13, wherein the Au end layer has a thickness of less than 1500 Å

and the total thickness of Au layers, comprising the Au end layer, is less than 15% of the thickness of the multilayer body.

15. The LED chip according to claim 9, wherein the multilayer body comprises a metal stacked structure formed by stacking two or more metals selected from the group consisting of Pt, Cr, Al, Ni, Ti, Au, Cu, Mo, W and Au.

16. An LED module comprising:

a mount substrate comprising electrodes;

an LED chip comprising a semiconductor stacked structure, a passivation layer covering the outer surface of the semiconductor stacked structure, and electrode pads connected to the outer surface of the semiconductor stacked structure through openings formed in the passivation layer; and

solder bumps connecting the electrode pads to the corresponding electrodes and formed using a solder material represented by Sn-M (where M is a metal),

wherein each of the electrode pads comprises a multilayer body comprising a plurality of metal layers and a contact body connected to the multilayer body, the contact body comprises a surface contact part in contact with the passivation layer outside the opening and an ohmic contact part in contact with the semiconductor stacked structure through the opening, the surface contact part in contact with the passivation layer blocks the Sn component of the solder bump from reaching the ohmic contact part through the opening, the ohmic contact part comprises an ohmic contact layer in direct contact with the semiconductor stacked structure and comprising Au and one or more metal layers formed on the ohmic contact layer and interposed between the ohmic contact layer and the surface contact part, and a ratio of an area of the opening to a surface area of the ohmic contact layer is from 0.1;

1 to 0.3;

1.

17. The LED module according to claim 16, wherein the multilayer body comprises an Au end layer at an end thereof, the Au end layer has a thickness of less than 1500 Å

, and the total thickness of Au layers, comprising the Au end layer, is less than 15% of the thickness of the multilayer body.

18. The LED module according to claim 16, wherein the multilayer body comprises a metal stacked structure formed by stacking two or more metals selected from the group consisting of Pt, Cr, Al, Ni, Ti, Au, Cu, Mo, W and Au.

19. The LED module according to claim 16, wherein the ohmic contact part comprises an ohmic contact layer in direct contact with the semiconductor stacked structure and the ratio of the area of the opening to the surface area of the ohmic contact layer is from 0.1:

1 to 0.3;

1.

20. The LED module according to claim 16, wherein the ohmic contact part comprises a metal compound comprising Au.

21. The LED module according to claim 16, wherein the ohmic contact part comprises an ohmic contact layer formed using a metal compound selected from the group consisting of GeAu, GeNiAu, TiPtAu, BeAu, and PdGeAu.

22. The LED module according to claim 16, wherein the semiconductor stacked structure comprises GaAs semiconductor layers.

23. The LED module according to claim 16, wherein each of the solder bumps partially covers the side surface of the electrode pad, the electrode pad comprises a metal stacked structure formed by stacking two or more metals, and Au is absent at a height of the metal stacked structure where the solder bump covers.

24. The LED module according to claim 16, wherein the multilayer body comprises an Au end layer, a diffusion barrier layer in contact with the Au end layer, and an adhesive layer in contact with the diffusion barrier layer.

25. The LED module according to claim 24, wherein the diffusion barrier layer is a Pt layer and the adhesive layer is a Ti layer.

26. The LED module according to claim 16, wherein the multilayer body comprises an Au end layer, a metal stacked structure consisting of Al layers and Ti layers stacked alternately on one another is formed between the Au end layer and the ohmic contact part, and the total thickness of the Al layers is two times that of the Ti layers.

27. The LED module according to claim 26, wherein a thickness of the Au end layer is smaller than those of the other metal layers in the metal stacked structure.