Lead frame, its manufacturing method, and semiconductor light emitting device using the same

• US 20110133232A1
• Filed: 02/04/2011
• Published: 06/09/2011
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Original Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Inventors: Tsukamoto, Takehito, Motomura, Hitoshi, Yoshioka, Osamu
• Granted Patent: US 8,841,692 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 21/4828 Etching etching for cleaning without patterning H01L21/4835
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01055 Cesium [Cs]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/15787 Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/60 Reflective elements
• 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
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

A lead frame comprises on a same plane, a pad part including an LED chip mounting upper surface A on which at least an LED chip is to be mounted, and a lead part including an electric connection area C in which an electric connection with the LED chip is made. A relationship between an area S1 of the mounting upper surface of the pad part 2 and an area S2 of a radiating lower surface opposite to the mounting upper surface is represented by 0<S1<S2. Side surfaces of the pad part between the mounting upper surface and the radiating lower surface are provided with stepped parts or tapered parts which spread in a direction from the mounting upper surface toward the radiating lower surface and hold a resin-filled during molding.

Claims

1. A lead frame comprising:

on a same plane,

a pad part 2 including an LED chip mounting upper surface A on which at least an LED chip 10 is to be mounted; and

a lead part 2a including an electric connection area C in which an electric connection with the LED chip is made,

wherein a relationship between an area S1 of the mounting upper surface A of the pad part 2 and an area S2 of a radiating lower surface B opposite to the mounting upper surface A is represented by 0<

S1<

S2, and

side surfaces of the pad part 2 between the mounting upper surface A and the radiating lower surface B are provided with stepped parts or tapered parts E which spread in a direction from the mounting upper surface A toward the radiating lower surface B and hold a resin-filled during molding.

2. The lead frame according to claim 1, wherein a relationship between an area S3 of the electric connection area C of the lead part 2a and an area S4 of a radiating lower surface D opposite to the electric connection area C and in plane with the radiating lower surface B of the pad part 2 is represented by 0<

S3<

S4, and

side surfaces of the lead part 2a between the electric connection area C and the radiating lower surface D are provided with stepped parts or tapered parts E which spread in a direction from the electric connection area C toward the radiating lower surface D and hold a resin-filled during molding.

5. The lead frame according to claim 1, wherein the pad part 2 and the lead part 2a of which both an upper surface and a lower surface are in a same plane form a unit frame, the each unit frame mutually connected via one or a plurality of tie bars and arranged in longitudinal and horizontal directions, and

an upper surface of each of the tie bars is lower than that of the pad part 2 and the lead part 2a, or a lower surface of each of the tie bars is higher than that of the pad part 2 and the lead part 2a, and

each of the tie bars is set to be smaller in thickness than the pad part 2 and the lead part 2a.

3. A lead frame comprising:

on a same plane,

a pad part 2 including an LED chip mounting upper surface A on which at least an LED chip 10 is to be mounted; and

a lead part 2a including an electric connection area C in which an electric connection with the LED chip is made,

wherein a relationship between an area S1 of the mounting upper surface A of the pad part 2 and an area S2 of a radiating lower surface B opposite to the mounting upper surface A is represented by 0<

S1<

S2,

the pad part 2 is formed of a first upper structure including the mounting upper surface A and a first lower structure integrated with the first upper structure and including the radiating lower surface B,

side surfaces of the first upper structure are provided with stepped parts or tapered parts E which spread in a direction from the mounting upper surface A toward the radiating lower surface B and hold a resin-filled during molding, and

side surfaces of the first lower structure are provided with stepped parts or tapered parts E1 which spread in a direction from the radiating lower surface B toward the mounting upper surface A and hold a resin-filled during molding.

4. The lead frame according to claim 3, wherein a relationship between an area S3 of the electric connection area C of the lead part 2a and an area S4 of a radiating lower surface D opposite to the electric connection area C and in plane with the radiating lower surface B of the pad part 2 is represented by 0<

S3<

S4,

the lead part 2a is formed of a second upper structure including the electric connection area C and a second lower structure integrated with the second upper structure and including the radiating lower surface D,

side surfaces of the second upper structure are provided with stepped parts or tapered parts E which spread in a direction from the electric connection area C towards the radiating lower surface D and hold a resin-filled during molding, and

side surfaces of the second lower structure are provided with stepped parts or tapered parts E1 which spread in a direction from the radiating lower surface D toward the electric connection area C and hold a resin-filled during molding.

6. A method of manufacturing lead frame comprising:

forming a photoresist pattern configured to form a mounting upper surface A including an area S1 of a pad part 2 on a upper surface of a plate-shaped lead frame metal material;

forming a photoresist pattern configured to form a radiating lower surface B including an area S2 opposite to the mounting upper surface A of the pad part 2 on a lower surface of the metal material; and

etching the metal material from both upper and lower surfaces to form stepped parts or tapered parts E, which spread in a direction from the mounting upper surface A toward the radiating lower surface B and hold a resin-filled during molding, on side surfaces of the pad part 2 between the mounting upper surface A and the radiating lower surface B for which a relationship between the area S1 of the mounting upper surface A of the pad part 2 and the area S2 of the radiating lower surface B is represented by 0<

S1<

S2.

7. The method of manufacturing lead frame according to claim 6, comprising:

forming a photoresist pattern configured to form an electric connection area C including an area S3 of a lead part 2a on the upper surface of the metal material when a photoresist pattern configured to form the mounting upper surface A is formed;

forming a photoresist pattern configured to form a radiating lower surface D including an area S4 opposite to the electric connection area C of the lead part 2a on the lower surface of the metal material when a photoresist pattern configured to form the radiating lower surface B is formed; and

etching the metal material from both upper and lower surfaces to form stepped parts or tapered parts E, which spread in a direction from the electric connection area C toward the radiating lower surface D and hold a resin-filled during molding, on side surfaces of the lead part 2a between the electric connection area C and the radiating lower surface D for which a relationship between the area S3 of the electric connection area C of the lead part 2a and the area S4 of the radiating lower surface C is represented by 0<

S3<

S4.

10. The method of manufacturing lead frame according to claim 6, wherein the pad part 2 and the lead part 2a of which both an upper surface and a lower surface are in a same plane form a unit frame, the each unit frame mutually connected via one or a plurality of tie bars and arranged in longitudinal and horizontal directions, and

an upper surface of each of the tie bars is lower than that of the pad part 2 and the lead part 2a, or a lower surface of each of the tie bars is higher than that of the pad part 2 and the lead part 2a, and

each of the tie bars is set to be smaller in thickness than the pad part 2 and the lead part 2a.

8. A method of manufacturing lead frame comprising:

forming a photoresist pattern configured to form a mounting upper surface A including an area S1 of a pad part 2 on the upper surface of a lead frame metal material;

forming a photoresist pattern configured to form a radiating lower surface B including an area S2 opposite to the mounting upper surface A of the pad part 2 on the lower surface of the metal material; and

etching the metal material from both upper and lower surfaces to form stepped parts or tapered parts E for which a relationship between the area S1 of the mounting upper surface A of the pad 2 and the area S2 of the radiating lower surface B is represented by 0<

S1<

S2 and the pad 2 is formed of an first upper structure including the mounting upper surface A and a first lower structure integrated with the first upper structure and including the radiating lower surface B, and which spread in a direction from the mounting upper surface A toward the radiating lower surface B on side surfaces of the first upper structure and hold a resin-filled during molding, and to form a stepped sections or tapered sections E1 which spread in a direction from the radiating lower surface B toward the mounting upper surface A on side surfaces of the first lower structure and hold a resin-filled during molding.

9. The method of manufacturing lead frame according to claim 8, comprising:

forming a photoresist pattern configured to form an electric connection area C including an area S3 of a lead part 2a on the surface of the metal material when a photoresist pattern configured to form the mounting upper surface A is formed;

forming a photoresist patter configured to form a radiating lower surface D including an area S4 opposite to the electric connection area C of the lead part 2a on the lower surface of the metal material when a photoresist pattern configured to form the radiating lower surface B is formed; and

etching the metal material from both surfaces to form stepped parts or tapered parts E for which a relationship between the area S3 of the electric connection area C of the lead 2a and the area S4 of the radiating lower surface D is represented by S3<

S4 and the lead 2a is formed of a second upper structure including the electric connection area C and a second lower structure integrated with the second upper structure and including the radiating lower surface D and which spread in a direction from the electric connection area C toward the radiating lower surface D on side surfaces of the second upper structure and hold a resin-filled during molding, and to form a stepped parts or tapered parts E1 which spread in a direction from the radiating lower surface D toward the electric connection area C on side surfaces of the lower structure and hold a resin-filled during molding.

11. A semiconductor light emitting device in which a lead frame comprising:

in a same plane,

a pad part 2 including an LED chip mounting upper surface A on which at least an IC chip such as an LED chip 10 is mounted; and

a lead part 2a including an electric connection area C in which an electric connection with the LED chip is made,

the lead frame molded with a resin-filled in a thickness direction from the mounting upper surface A toward a radiating lower surface B opposite to the mounting upper surface A, and a transparent resin covering the mounting upper surface A of the pad part 2 while including the LED chip and the electric connection area C,

wherein a relationship between an area S1 of the mounting upper surface A of the pad part 2 and an area S2 of the radiating lower surface B is represented by 0<

S1<

S2,

side surfaces of the pad part 2 between the mounting upper surface A and the radiating lower surface B are provided with stepped parts or tapered parts E which spread in a direction from the mounting upper surface A toward the radiating lower surface B, and

the resin-filled is held in the stepped parts or tapered parts E.

13. The device according to claim 11, wherein a relationship between an area S3 of the electric connection area C of the lead part 2a and an area S4 of a radiating lower surface D opposite to the electric connection area C and in plane with the radiating lower surface B of the pad part 2 is represented by 0<

S3<

S4,

side surfaces of the lead part 2a between the electric connection area C and the radiating lower surface D are provided with stepped parts or tapered parts E which spread in a direction from the electric connection area C toward the radiating lower surface D and hold the resin-filled, and

the resin-filled is held in the stepped parts or tapered parts E.

14. The device according to claim 11, wherein a relationship between an area S3 of the electric connection area C of the lead part 2a and an area S4 of a radiating lower surface D opposite to the electric connection area C and in plane with the radiating lower surface B of the pad part 2 is represented by 0<

S3<

S4,

the lead part 2a is formed of an upper structure including the electric connection area C and a lower structure integrated with the upper structure and including the radiating lower surface D,

side surfaces of the upper structure are provided with stepped parts or tapered parts E which spread in a direction from the electric connection area C toward the radiating lower surface D and hold a resin-filled during resin molding,

side surfaces of the lower structure are provided with stepped parts or tapered parts E1 which spread in a direction from the radiating lower surface D toward the electric connection area C and hold a resin-filled during resin molding, and

the resin-filled is held in the stepped parts or tapered parts E and E1.

15. The device according to claim 11, wherein a relationship between an optical refraction index n1 of the resin-filled and an optical refraction index n2 of the transparent resin is set at n1>

n2 and the resin-filled has a high reflectivity.

16. The device according to claim 11, wherein the resin-filled is added with a particulate for improving a reflecting property.

12. A semiconductor light emitting device in which a lead frame comprising:

in a same plane,

a pad part 2 including an LED chip mounting upper surface A on which at least an IC chip such as an LED chip 10 is mounted; and

a lead part 2a including an electric connection area C in which an electric connection with the LED chip is made,

the lead frame molded with a resin-filled in a thickness direction from the mounting upper surface A toward a radiating lower surface B opposite to the mounting upper surface A, and a transparent resin covering the mounting upper surface A of the pad part 2 while including the LED chip and the electric connection area C,

wherein a relationship between an area S1 of the mounting upper surface A of the pad part 2 and an area S2 of the radiating lower surface B is represented by 0<

S1<

S2,

the pad is formed of an upper structure including the mounting upper surface A and a lower structure integrated with the upper structure and including the radiating lower surface,

side surfaces of the upper structure are provided with stepped parts or tapered parts E from the mounting upper surface A toward the radiating lower surface B,

side surfaces of the lower structure are provided with stepped parts or tapered parts E1 from the radiating lower surface B toward the mounting upper surface A, and

the resin-filled is held in the stepped parts or tapered parts E and E1.

17. A lead frame comprising:

structures in which an upper structure on the upper surface and a lower structure on the lower surface are integrated together, the structures separated from each other;

a resin-filled formed between and outside the structures and having the same thickness as the structures,

the upper structure including a pad part 2 and a lead part 2a separated from the pad part 2,

the lower structure including a radiator 3 integrated with the pad part 2 and a radiator 3a integrated with the lead part 2a,

a relationship between an area S1 of the surface of the pad part 2 and an area S2 of the lower surface of the radiator 3 represented by 0<

S1<

S2,

a relationship between an area S3 of the surface of the lead part 2a and an area S4 of the lower surface of the radiator 3a represented by 0<

S3<

S4,

side surfaces of the each upper structure provided with stepped parts or tapered parts which spread in a direction from the upper surface of the structures toward the lower surface thereof, and

side surfaces of the each lower structure provided with stepped parts or tapered parts which spread in a direction from the lower surface of the lead frame toward the surface thereof; and

a light reflecting ring 4a formed on the upper surface and outside the pad part 2 and the lead part 2a, the light reflecting ring 4a comprising an inner periphery surface tilted to the pad part 2, and the light reflecting ring 4a integrally formed with the resin-filled and projecting from the resin-filled.

18. The lead frame according to claim 17, wherein a tilt angle of the inner periphery surface of the light reflecting ring 4a relative to the upper surface of the pad part 2 is between 30 degrees and 85 degrees.

19. The lead frame according to claim 17, wherein the resin-filled is a light diffusing resin mixed with a powdery additive and has an optical refraction index of 2 or more.

20. The lead frame according to claim 17, wherein the pad part 2 and the lead part 2a of which both an upper surface and a lower surface are in a same plane form unit frame, the each unit frame mutually connected via one or a plurality of tie bars and arranged in longitudinal and horizontal directions, and

an upper surface of each of the tie bars is lower than that of the pad part 2 and the lead part 2a, or a lower surface of each of the tie bars is higher than that of the pad part 2 and the lead part 2a, and

each of the tie bars is set to be smaller in thickness than the pad part 2 and the lead part 2a.

21. A method of manufacturing lead frame comprising:

forming photoresist patterns configured to form a chip mounting upper surface A including an area S1 of a pad part 2 and an electric connection area C including an area S3 of a lead part 2a on a surface of a lead frame metal material;

forming photoresist patterns configured to form a radiating lower surface B including an area S2 opposite to the chip mounting upper surface A and a radiating lower surface D including an area S4 opposite to the electric connection area C on a lower surface of the metal material;

etching the metal material from both surfaces to form an integrated structure including an upper structure and a lower structure made of the metal material for which a relationship between the area S1 of the chip mounting upper surface A of the pad part 2 and the area S2 of the radiating lower surface B is set at 0<

S1<

S2 and a relationship between the area S3 of the electric connection area C and the area S4 of the radiating lower surface D is set at 0<

S3<

S4, to form stepped parts or tapered parts E which spread in a direction from the chip mounting upper surface A toward the radiating lower surface B on side surfaces of the upper structure, to form stepped parts or tapered parts E1 which spread in a direction from the radiating lower surface B toward the chip mounting upper surface A on side surfaces of the lower structure, to integrally form the pad part 2 including the chip mounting upper surface A in the upper structure and a radiator 3 including the radiating lower surface B in the lower structure, and to integrally form the lead part 2a including the electric connection area C in the upper structure and a radiator 3a including the radiating lower surface D in the lower structure;

providing an integrated structure including the upper structure and the lower structure in a mold for molding; and

filling and molding a resin in the mold to form a resin-filled having the same thickness as the integrated structure including the upper structure and the lower structure around the integrated structure including the upper structure and the lower structure, and to form a light reflecting ring 4a for light reflection including an inner periphery surface tilted to the chip mounting upper surface A at side of the mounting upper surface A and outside the pad part 2 and the lead part 2a, at the same time as the formation of the resin-filled so as to form the light reflecting ring 4a to be integral with the resin-filled and be projected from the resin-filled.

22. The method according to claim 21, wherein the pad part 2 and the lead part 2a of which both an upper surface and a lower surface are in a same plane form unit frame, the each unit frame mutually connected via one or a plurality of tie bars and arranged in longitudinal and horizontal directions, and

an upper surface of each of the tie bars is lower than that of the pad part 2 and the lead part 2a, or a lower surface of each of the tie bars is higher than that of the pad part 2 and the lead part 2a, and

each of the tie bars is set to be smaller in thickness than the pad part 2 and the lead part 2a.

23. A semiconductor light emitting device comprising:

a lead frame including structures in which an upper structure on a upper surface and a lower structure on a lower surface are integrated, structures separated from one another;

a resin-filled which is formed between and outside the structures of the lead frame and has the same thickness as the lead frame,

the upper structure including a pad part 2, and a lead part 2a separated from the pad part 2,

the lower structure including a radiator 3 integrated with the pad part 2 and a radiator 3a integrated with the lead part 2a,

side surfaces of the each upper structure provided with stepped parts or tapered parts which spread in a direction from the surface of the lead frame toward the lower surface thereof,

side surfaces of the each lower structure provided with stepped parts or tapered parts which spread in a direction from the lower surface of the lead frame toward the surface thereof; and

a light reflecting ring 4a for light reflection on the upper surface and outside the pad part 2 and the lead part 2a, the light reflecting ring 4a including an inner periphery surface tilted relative to the pad part, integrally formed with the resin-filled, and projecting from the resin-filled,

an LED chip is mounted on the surface of the pad part 2,

an electrode of the LED chip is electrically connected to the lead part 2a, and

a transparent resin which covers the LED chip and contacts the inner periphery surface of the light reflecting ring 4a is formed.

24. The device according to claim 23, wherein a relationship between an area S1 of the surface of the pad part 2 and an area S2 of the lower surface of the radiator 3 is represented by 0<

S1<

S2, and

a relationship between an area S3 of the surface of the lead part 2a and an area S4 of the lower surface of the radiator 3a is represented by 0<

S3<

S4.

25. The device according to claim 23, wherein the resin-filled is a light diffusing resin in which a powdery additive is mixed into a resin, and has an optical refraction index of 2 or more, which is higher than a refraction index of the transparent resin.