Heat sink board for a semiconductor device

Abstract

A semiconductor package according to an embodiment of the present invention includes: a heat sink board including an insulated board and a first metal layer formed on the insulated board; at least one semiconductor chip placed on the first metal layer; a plurality of lead frames connected to the semiconductor chips used to electrically connect the semiconductor chips to the outside; and a package housing partially covering the heat sink board, wherein both end parts of the insulated board are projected further than both end parts of the first metal layer.

Claims

1. A heat sink board comprising: an insulated board; a first metal layer formed on the insulated board, wherein ends of the insulated board are projected further than ends of the first metal layer, respectively; and a second metal layer formed on the first metal layer, wherein the ends of the first metal layer are aligned with ends of the second metal layer, respectively, wherein the insulated board has a thickness greater than a sum of thicknesses of the first and second metal layers, wherein the sum of the thicknesses of the first and second metal layers is 1 micrometer to 100 micrometers, wherein materials of the first and second metal layers are different from each other.

2. The heat sink board of claim 1, wherein the second metal layer comprises a plurality of stacked sub metal layers.

3. The heat sink board of claim 1, wherein the ends of the insulated board are projected further toward the outside than the ends of the first metal layer by 5 micrometers to 8 cm.

4. The heat sink board of claim 1, wherein the first metal layer comprises any one selected from silver (Ag) and an alloy comprising above 50% of silver (Ag).

5. The heat sink board of claim 1, wherein any one of the first metal layer and the second metal layer comprises any one selected from nickel (Ni), copper (Cu), and an alloy comprising above 50% of nickel (Ni) or copper (Cu).

6. The heat sink board of claim 1, wherein the thickness of the insulated board is 0.1 mm to 10 mm.

7. The heat sink board of claim 1, wherein the second metal layer is configured to be directly attached to a lower surface of a semiconductor chip.

8. A method of manufacturing a heat sink board comprising: forming a first metal layer on an insulated board by using a plating process or a sputtering process; and forming a second metal layer on the first metal layer, ends of the first metal layer being aligned with ends of the second metal layer, respectively, wherein ends of the insulated board are projected further than the ends of the first metal layer, wherein the insulated board has a thickness greater than a sum of thicknesses of the first and second metal layers, wherein the sum of the thicknesses of the first and second metal layers is 1 micrometer to 100 micrometers, wherein materials of the first and second metal layers are different from each other.

9. The method of claim 8, further comprising attaching a semiconductor chip directly to an upper surface of the second metal layer.

10. A semiconductor package comprising: a heat sink board comprising an insulated board, a first metal layer formed on the insulated board, and a second metal layer formed on the first metal layer, ends of the first metal layer being aligned with ends of the second metal layer, respectively; at least one semiconductor chip placed on the second metal layer; a plurality of lead frames connected to the semiconductor chips used to electrically connect the semiconductor chips to the outside; and a package housing partially covering the heat sink board, wherein ends of the insulated board are projected further than the ends of the first metal layer, respectively, wherein the insulated board has a thickness greater than a sum of thicknesses of the first and second metal layers, wherein the sum of the thicknesses of the first and second metal layers is 1 micrometer to 100 micrometers, wherein materials of the first and second metal layers are different from each other.

11. The semiconductor package of claim 10, wherein the first metal layer comprises any one selected from silver (Ag) and an alloy comprising above 50% of silver (Ag).

12. The semiconductor package of claim 10, wherein any one of the first metal layer and the second metal layer comprises any one selected from nickel (Ni), copper (Cu), and an alloy comprising above 50% of nickel (Ni) or copper (Cu).

13. The semiconductor package of claim 10, wherein the thickness of the insulated board is 0.1 mm to 10 mm.

14. The semiconductor package of claim 10, wherein the heat sink board has more than 50% of area exposed to the outside of the package housing.

15. The semiconductor package of claim 10, further comprising a plurality of connecting means electrically connecting each of the plurality of semiconductor chips, wherein the connecting means comprise a metal clip or a metal spacer and are attached to chip pads of the semiconductor chips.

16. The semiconductor package of claim 10, wherein the semiconductor chip is directly attached to an upper surface of the second metal layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

(2) FIG. 1 is a cross-sectional view of a heat sink board according to an embodiment of the present invention;

(3) FIG. 2 is a perspective view of a heat sink board according to an embodiment of the present invention;

(4) FIG. 3 is a cross-sectional view of a heat sink board according to another embodiment of the present invention;

(5) FIG. 4 is a flowchart illustrating a method of manufacturing a heat sink board according to another embodiment of the present invention;

(6) FIG. 5 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention;

(7) FIG. 6 is a perspective view of a semiconductor package according to an embodiment of the present invention;

(8) FIG. 7 is an exploded perspective view of a part in FIG. 6; and

(9) FIG. 8 is an enlarged perspective view of a metal clip connected to a lead frame illustrated in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

(10) Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings to be easily implemented by those of ordinary skill in the art. This invention may be embodied in many alternate forms and should not be construed as limited to only the exemplary embodiments set forth herein.

(11) FIG. 1 is a cross-sectional view of a heat sink board 100 according to an embodiment of the present invention and FIG. 2 is a perspective view of the heat sink board 100 according to an embodiment of the present invention.

(12) As illustrated in FIGS. 1 and 2, the heat sink board 100 according to an embodiment of the present invention includes an insulated board 10 and a first metal layer 20 formed on the insulated board 10.

(13) The insulated board 10 may include any one selected from ceramic (Al.sub.2O.sub.3), aluminum nitride (AlN), silicon nitride (Si.sub.3N.sub.4), aluminum silicon carbide (AlSiC), silicon carbide (SiC), zirconium (Zr), and a mixture thereof. A thickness of the insulated board 10 may be 0.1 mm to 10 mm.

(14) The first metal layer 20 may include any one selected from a single metal including silver (Ag) and an alloy including above 50% of silver (Ag). Also, the first metal layer 20 may include any one selected from a single metal including nickel (Ni), a single metal including copper (Cu), and an alloy including above 50% of nickel (Ni) or copper (Cu).

(15) A thickness of the first metal layer 20 may be 1 um to 100 um. As such, the thickness of the first metal layer 20 may be thinner than the thickness of the insulated board 10 so that heat emission effect may be greatly increased.

(16) Both end parts 10a and 10b of the insulated board 10 may be projected further toward the outside than both end parts 20a and 20b of the first metal layer 20.

(17) Here, the end part 10a of the insulated board 10 may be projected further toward the outside than the end part 20a of the first metal layer 20 by a first projected length D1 of 5 um to 8 cm. As in the same manner, the other end part 10b of the insulated board 10 may be projected further toward the outside than the other end part 20b of the first metal layer 20 by a second projected length D2 of 5 um to 8 cm.

(18) Here, the first projected length D1 and the second projected length D2 may be the same or different from each other.

(19) According to an embodiment of the present invention, the first metal layer 20 is only formed on the insulated board 10, however, a second metal layer 30 may be formed on the first metal layer 20 in another embodiment of the present invention.

(20) Hereinafter, the heat sink board 100 according to another embodiment of the present invention will be described in detail with reference to FIG. 3.

(21) FIG. 3 is a cross-sectional view of the heat sink board 100 according to another embodiment of the present invention.

(22) The description in the embodiment illustrated in FIG. 3 is the same as that of in the embodiment illustrated in FIGS. 1 and 2 except for structures of the second metal layer 30 and thus, the same description is omitted herein.

(23) As illustrated in FIG. 3, the heat sink board 100 according to another embodiment of the present invention includes the insulated board 10, the first metal layer 20 formed on the insulated board 10, and the second metal layer 30 formed on first metal layer 20.

(24) Here, the both end parts 20a and 20b of the first metal layer 20 and both end parts 30a and 30b of the second metal layer 30 may be placed at the same imaginary lines L1 and L2.

(25) A thickness of the insulated board 10 may be 0.1 mm to 10 mm. Also, the both end parts 10a and 10b of the insulated board 10 may be projected further toward the outside than the both end parts 20a and 20b of the first metal layer 20. As in the same manner, the both end parts 10a and 10b of the insulated board 10 may be projected further toward the outside than the both end parts 30a and 30b of the second metal layer 30.

(26) Here, the end part 10a of the insulated board 10 may be projected further toward the outside than the end part 20a of the first metal layer 20 or the end part 30a of the second metal layer 30 by the first projected length D1 of 5 um to 8 cm. As in the same manner, the other end part 10b of the insulated board 10 may be projected further toward the outside than the other end part 20b of the first metal layer 20 or the other end part 30b of the second metal layer 30 by the second projected length D2 of 5 um to 8 cm. Here, the first projected length D1 and the second projected length D2 may be the same or different from each other.

(27) The second metal layer 30 may include a plurality of stacked sub metal layers 31. In the embodiment of FIG. 3, three sub metal layers 31 are illustrated. However, the present invention is not limited thereto and various numbers of sub metal layer 31 may be formed.

(28) The thickness of the first metal layer 20 and the second metal layer 30 may be respectively 1 um to 100 um. However, the present invention is not limited thereto and the sum of the thickness of the first metal layer 20 and the second metal layer 30 may be 1 um to 100 um.

(29) Hereinafter, a method of manufacturing the heat sink board 100 illustrated in FIG. 3 above will be described in detail.

(30) FIG. 4 is a flowchart illustrating a method of manufacturing the heat sink board 100 according to another embodiment of the present invention.

(31) As illustrated in FIG. 4, the method of manufacturing the heat sink board 100 firstly includes forming of the first metal layer 20 having a small thickness on the insulated board 10 by using a plating process or a sputtering process, in operation S10. The plating process may include electroplating or electroless plating. Since the first metal layer 20 is formed by using a plating process or a sputtering process, the first metal layer 20 having a reduced thickness may be formed and thus, manufacturing costs may be reduced so that heat emission effect may be greatly increased.

(32) Here, the both end parts 10a and 10b of the insulated board 10 may be projected further toward the outside than the both end parts 20a and 20b of the first metal layer 20.

(33) Next, the second metal layer 30 may be formed on the first metal layer 20 by using a plating process or a sputtering process, in operation S20. Here, the both end parts 20a and 20b of the first metal layer 20 and the both end parts 30a and 30b of the second metal layer 30 may be placed at the same imaginary lines L1 and L2.

(34) As described above, when the first metal layer 20 and the second metal layer 30 are both formed by using a plating process or a sputtering process, the first metal layer 20 and the second metal layer 30 may have a reduced thickness so that manufacturing costs may be reduced and heat emission effect may be greatly increased.

(35) FIG. 5 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention, FIG. 6 is a perspective view of a semiconductor package according to an embodiment of the present invention, FIG. 7 is an exploded perspective view of a part in FIG. 6, and FIG. 8 is an enlarged perspective view of a metal clip connected to a lead frame illustrated in FIG. 6.

(36) As illustrated in FIGS. 5 through 8, a semiconductor package according to an embodiment of the present invention includes the heat sink board 100, at least one semiconductor chip 200, a plurality of lead frames 300, a plurality of connecting members 400, and a package housing 500.

(37) The heat sink board 100 includes the insulated board 10 and the first metal layer 20 formed on the insulated board 10. In the current embodiment of the present invention, the first metal layer 20 is only illustrated. However, the present invention is not limited thereto and the second metal layer 30 having a plurality of sub metal layers 31 may be formed.

(38) The insulated board 10 may include any one selected from ceramic (Al.sub.2O.sub.3), aluminum nitride (AlN), silicon nitride (Si.sub.3N.sub.4), aluminum silicon carbide (AlSiC), silicon carbide (SiC), zirconium (Zr), and a mixture thereof. A thickness of the insulated board 10 may be 0.1 mm to 10 mm.

(39) The first metal layer 20 may include any one selected from a single metal including silver (Ag) and an alloy including above 50% of silver (Ag). Also, the first metal layer 20 may include any one selected from a single metal including nickel (Ni), a single metal including copper (Cu), and an alloy including above 50% of nickel (Ni) or copper (Cu).

(40) A thickness of the first metal layer 20 may be 1 um to 100 um. As such, the thickness of the first metal layer 20 may be thinner than the thickness of the insulated board 10 so that heat emission effect may be greatly increased.

(41) The both end parts 10a and 10b of the insulated board 10 may be projected further toward the outside than the both end parts 20a and 20b of the first metal layer 20. Here, the end part 10a of the insulated board 10 may be projected further toward the outside than the end part 20a of the first metal layer 20 by the first projected length D1 of 5 um to 8 cm. As in the same manner, the other end part 10b of the insulated board 10 may be projected further toward the outside than the other end part 20b of the first metal layer 20 by the second projected length D2 of 5 um to 8 cm. Here, the first projected length D1 and the second projected length D2 may be the same or different from each other.

(42) The heat sink board 100 according to an embodiment of the present invention illustrated in FIGS. 5 through 8 is applied from the heat sink board 100 illustrated in FIGS. 1 and 2. However, the present invention is not limited thereto and the heat sink board 100 according to another embodiment of the present invention illustrated in FIG. 3 may be applicable.

(43) As illustrated in FIGS. 5 through 8, the semiconductor chips 200 may be placed on the first metal layer 20. Such semiconductor chips 200 may be attached to the first metal layer 20 by using an adhesive means 220 through a soldering process, a silver (Ag) sintering process, or a copper (Cu) sintering process.

(44) The semiconductor chips 200 may include any one selected from metal-oxide semiconductor filed effect transistor (MOSFET), insulated gate bipolar transistor (IGBT), and diode. Such semiconductor chips 200 may be formed of any one selected from silicon (Si), silicon carbide (SiC), and gallium nitride (GaN). The semiconductor chips 200 may include a chip pad 210 used to electrically connect to connecting means 400.

(45) The plurality of connecting means 400 may be used to electrically connect each of the plurality of semiconductor chips 200. Such connecting means 400 may include a metal clip or a metal spacer and FIG. 8 illustrates the connecting means 400 formed with metal clips. The connecting means 400 may be attached and electrically connected to the chip pads 210 of the semiconductor chips 200.

(46) The lead frames 300 are connected to the semiconductor chips 200 through the plurality of connecting means 400 and electrically connect the semiconductor chips 200 to the outside.

(47) Here, the lead frames 300 may be attached to the first metal layer 20 of the heat sink board 100 through an ultrasonic welding process without using an additional adhesive means.

(48) The package housing 500 may partially cover the heat sink board 100 in order to protect the heat sink board 100. Here, more than 50% of area of the heat sink board 100 may be exposed to the outside of the package housing 500. Accordingly, heat emission effect may be greatly increased. Such a package housing 500 may be formed of any one selected from epoxy molding compound (EMC), polybutylene terephthalate (PBT), and polyphenylene sulfide (PPS).

(49) In the heat sink board and the semiconductor package including the heat sink board according to an embodiment of the present invention, the metal layers are formed on the insulated board by using a plating process or a sputtering process and thus, manufacturing costs may be reduced.

(50) In addition, since the metal layers are formed by using a plating process or a sputtering process, the metal layers may have reduced thicknesses and thus, heat emission effect may be greatly increased.

(51) While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.