Light Emitting Device and Method of Manufacturing the Same

• US 20080191632A1
• Filed: 08/07/2006
• Published: 08/14/2008
• Est. Priority Date: 08/10/2005
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: Lee, Jae Ho
• Granted Patent: US 7,897,981 B2
• Time in Patent Office: Days
• US Class Current: 315/185.00R
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers

Abstract

The present invention provides a light emitting device comprising a first semiconductor substrate including a light emitting cell block having a plurality of light emitting cells connected in series on one surface thereof; a second semiconductor substrate having one surface formed with a rectifying bridge and the other surface bonded to the other surface of the first semiconductor substrate; and a submount substrate to which the second semiconductor substrate is flip-chip bonded to be in contact with the one surface of the second semiconductor substrate, wherein rectified power is applied to the light emitting cell block through the rectifying bridge. The present invention further provides a method of manufacturing the light emitting device. The light emitting device and the method of manufacturing the same according to the present invention have advantages in that a flicker effect generated from an AC power source can be minimized and constant brightness can be maintained even in changes in the voltage of the AC power source by integrating a rectifying circuit into a light emitting device with a flip-chip structure, and in that there is no cumbersomeness of mounting an additional auxiliary device, resulting in increase of the degree of utilization of space and improved light output.

Claims

1. A light emitting device, comprising:

a first semiconductor substrate including a light emitting cell block having a plurality of light emitting cells connected in series on one surface thereof;

a second semiconductor substrate having one surface formed with a rectifying bridge and the other surface bonded to the other surface of the first semiconductor substrate; and

a submount substrate to which the second semiconductor substrate is flip-chip bonded to be in contact with the one surface of the second semiconductor substrate,

wherein rectified power is applied to the light emitting cell block through the rectifying bridge.

2. The light emitting device as claimed in claim 1, wherein the rectifying bridge comprises:

a first diode block connected between first and second nodes;

a second diode block connected between the first node and a fourth node;

a third diode block connected between the second node and a third node; and

a fourth diode block connected between the third and fourth nodes.

3. The light emitting device as claimed in claim 2, wherein the light emitting cell block is connected between the second and fourth nodes, and a power source is connected between the first and third nodes.

4. The light emitting device as claimed in claim 2, wherein the submount substrate comprises first and second connection pads and first and second power supply pads, the connection and the power supply pads being formed to be spaced apart form one another, and

the first power supply pad is connected between the first and second diode blocks, the second power supply pad is connected between the third and fourth diode blocks, the first connection pad is connected between the first and third diode blocks, the second connection pad is connected between the second and fourth diode blocks, and both ends of the light emitting cell block are respectively connected to the first and second connection pads.

5. The light emitting device as claimed in claim 1, wherein each of the plurality of light emitting cells of the light emitting cell block comprises N-type and P-type semiconductor layers, and

the N-type and P-type semiconductor layers of adjacent light emitting cells are electrically connected, an N-type bonding pad is formed on the N-type semiconductor layer of the light emitting cell at one end of the light emitting cell block, and a P-type bonding pad is formed on the P-type semiconductor layer of the light emitting cell at the other end of the light emitting cell block.

6. The light emitting device as claimed in claim 1, wherein uneven portion are formed on at least one surface of the first or second semiconductor substrate.

7. A method of manufacturing a light emitting device, comprising the steps of:

providing a first semiconductor substrate by forming a light emitting cell block having a plurality of light emitting cells connected in series on one surface of a first substrate;

providing a second semiconductor substrate by forming a rectifying bridge on one surface of a second substrate;

bonding the first and second substrates such that the other surfaces of the first and second substrates are in contact with each other; and

bonding the second substrate to a submount substrate such that the rectifying bridge of the second semiconductor substrate is connected thereto, and connecting the light emitting cell block to the rectifying bridge.

8. The method as claimed in claim 7, wherein the step of providing the first semiconductor substrate comprises the steps of:

sequentially forming N-type and P-type semiconductor layers on the one surface of the first substrate;

partially removing the N-type and P-type semiconductor layers to form a plurality of light emitting cells; and

connecting the N-type semiconductor layer of one light emitting cell to the P-type semiconductor of another light emitting cell adjacent thereto through a bridge wire.

9. The method as claimed in claim 7, wherein the step of providing the second semiconductor substrate comprises the step of forming four diode blocks each of which has one or more light emitting cells on the one surface of the second substrate.

10. The method as claimed in claim 9, wherein the step of forming the diode blocks comprises the steps of:

forming a plurality of light emitting cells on the one surface of the second substrate;

connecting the N-type semiconductor layer of one light emitting cell and the P-type semiconductor of another light emitting cell adjacent thereto through a bridge wire; and

forming an N-type bonding pad on the N-type semiconductor layer of the light emitting cell at one end of the diode block, and forming a P-type bonding pad on the P-type semiconductor layer of the light emitting cell at the other end of the diode block.

11. The method as claimed in claim 8, wherein the bridge wire connects the N-type semiconductor layer of one light emitting cell to the P-type semiconductor layer of the other light emitting cell adjacent thereto through a bridge process or a step coverage process.

12. The method as claimed in claim 7, further comprising the step of forming uneven portion on the one surface of the first substrate before the step of providing the first semiconductor substrate.