Title of Invention	"SEMICONDUCTOR DEVICE AND A METHOD FOR MANUFACTURE THEREOF"
Abstract	A mount 2 is secured on a circuit board 1 to support a diode chip 3 thereon. A plurality of legs 7, 12 formed in the mount 2 are in contact with an electrode 4 on the circuit board 1 to form at least a dent 14. The mount 2 also has an inclined surface 8 formed at the periphery which faces the electrode 4. Solder 9 is filled in the dent 14 between the legs 7, 12 and in the flaring area 13 between the circuit board 1 and the inclined surface 8 of the mount 2 to prevent exfoliation or detachment of the mount from the electrode 4. (Fig. 1)

Title of Invention

"SEMICONDUCTOR DEVICE AND A METHOD FOR MANUFACTURE THEREOF"

Abstract

A mount 2 is secured on a circuit board 1 to support a diode chip 3 thereon. A plurality of legs 7, 12 formed in the mount 2 are in contact with an electrode 4 on the circuit board 1 to form at least a dent 14. The mount 2 also has an inclined surface 8 formed at the periphery which faces the electrode 4. Solder 9 is filled in the dent 14 between the legs 7, 12 and in the flaring area 13 between the circuit board 1 and the inclined surface 8 of the mount 2 to prevent exfoliation or detachment of the mount from the electrode 4. (Fig. 1)

Full Text	ing slant attachment of a mount on a circuit board. Another object of the invention is to provide a semiconductor device which has a mount certainly secured on a circuit board correctly in the upright condition. Summary of the Invention The semiconductor device according to the present invention includes a support, a mount secured on the support by brazing metal and a semiconductor element secured on the mount. The mount is formed with at least an inclined surface formed at the periphery which faces the support and a plurality of legs formed inside the inclined surface to form at least a dent between the legs. The inclined surface is divergent away from the support, and the legs are in contact with the support. The brazing metal is disposed in a gap including the dent and a flaring area between the support and the inclined surface of the mount between the support and mount. In an embodiment of the present invention, the mount is formed into substantially rectangular shape to form four inclined surfaces, and the legs forms a cross dent inwardly extending from each inclined surface. The legs are formed into columns or elongated protrusions separated from each other, extending from the mount. The support includes a circuit board on which at least an electrode and circuit conductor are formed thereon for electrical connection. The method for manufacturing a semiconductor device according to the present invention comprises the steps of: providing a mount formed with a plurality of integrally formed legs and at least an inclined surface formed at the periphery; piling in turn on an electrode fonncd on a support, an adhesive solder paste, the mount, an adhesive solder past and a semiconductor chip to form a subassembly; and heating the subassembly to re-fuse the solder pastes and then cooling same for full setting to simultaneously bond the mount and semiconductor chip on the support. Gas produced in brazing metal is released during the heating process through at least a dent formed between the legs and the inclined surface out of the brazing metal, thus preventing trapping of bubbles therein. The legs formed in the mount are effective to prevent slant attachment of the mount on the support with substantially uniform thickness of brazing metal between the support and mount. In addition, the mount is firmly bonded on the support by brazing metal filled in the dent between the legs and in the flaring area between the support and the inclined surface of the mount to prevent exfoliation or detachment of the mount from the support when the semiconductor device is used under severe variation of ambient temperature. As a result, the semiconductor device can keep good electric properties during its long duration and improve yield in manufacture. A plurality of legs separated from each other provide stable attachment of the mount against its inclined condition because gas produced in brazing metal is released through the dent out of the brazing metal, thus preventing trapping of bubbles therein and enhancement of braze strength. The above-mentioned as well as other objects of the present invention will become apparent during the course of the following detailed description and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partial section view of an embodiment of the semiconductor device according to the present invention. Fig. 2 is a partial plan view of the semiconductor device. Fig. 3 is a side view of a mount used in the semiconductor device shown in Fig. 1. Fig. 4 is a bottom view of the mount. Fig. 5 is a partial section view of a second embodiment of the semiconductor device according to the present invention. Fig. 6 is a side view of the mount used in the second embodiment shown in Fig- 5. Fig. 7 is a bottom view of the mount used in the second embodiment shown in Fig. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Figs. 1 to 4 indicate a first embodiment of the semiconductor device according to the present invention. As shown in Fig. 1, the semiconductor device comprises a circuit board 1 to form a support of ceramics such as alumina (Al2O3), a mount 2 secured on the circuit board 1, and a diode chip 3 of silicon (Si) as a semiconductor clement. Not shown but, the mount 2 We Claim 1 A semiconductor device comprising a support (1), a mount (2) secured on said support (1) by brazing metal (9) and a semiconductor element (3) secured on said mount (2); said mount (2) being formed of metallic material which comprises a main body (6); at least an inclined surface (8) formed at the periphery of said main body (6) to face said support (1); and a plurality of legs (7) extending from said main body (6) inside said inclined surface (8) to form at least a dent (14) between said legs (7); said inclined surface (8) being divergent away from said support (1); said legs (7) being in direct contact with said support (1) to prevent inclined arrangement of said mount (2); said mount (2) being firmly secured on said support (1) by brazing metal (9) filled in a gap which includes said dent (14) and a flaring area (13) formed between said support (1) and inclined surface (8) of said mount (2). 2 The semiconductor device of claim 1, wherein said mount (2) is formed into substantially rectangular shape to form four inclined surfaces (8); said legs (7) forms the dent (14) inwardly extending from each inclined surface (8). 3 The semiconductor device of claim 1, wherein said legs (7) are formed into columns separated from each other, extending from said mount (2). 4 The semiconductor device of claim 1, wherein said legs (7) are formed into elongated protrusions separated from each other, extending from said mount (2). 5 The semiconductor device of claim 1, wherein said support (1) includes a circuit board on which at least an electrode and circuit conductor are formed for electrical connection. 6 A method for manufacturing a semiconductor device comprising the steps of: providing a mount (2) formed with a plurality of integrally formed legs (7) and at least an inclined surface (8) formed at the periphery; piling in turn on an electrode (4) formed on a support (1), an adhesive solder paste, said mount (2), an adhesive solder paste and a semiconductor element (3) to form a subassembly; and heating said subassembly to re-fuse said solder pastes and then cooling same for full setting to simultaneously bond said mount (2) and semiconductor element (3) on said support (1); said legs (7) being in direct contact with said support (1) to prevent inclined disposition of said mount (2); said mount (2) being secured on said support (1) by brazing metal (9) filled in a gap which includes said dent (14) and a flaring area (13) formed between said support (1) and inclined surface (8) of said mount (2). 7 The method of claim 6, wherein gas produced in brazing metal (9) is released during said heating process through at least a dent (14) formed between said legs (7) and said inclined surface (8) out of the brazing metal (9), thus preventing trapping of bubbles therein. 8. A semiconductor device substantially as herein described with reference to by the accompanying drawings.

Full Text

ing slant attachment of a mount on a circuit board.
Another object of the invention is to provide a semiconductor device which has a mount certainly secured on a circuit board correctly in the upright condition.
Summary of the Invention
The semiconductor device according to the present invention includes a support, a mount secured on the support by brazing metal and a semiconductor element secured on the mount. The mount is formed with at least an inclined surface formed at the periphery which faces the support and a plurality of legs formed inside the inclined surface to form at least a dent between the legs. The inclined surface is divergent away from the support, and the legs are in contact with the support. The brazing metal is disposed in a gap including the dent and a flaring area between the support and the inclined surface of the mount between the support and mount.
In an embodiment of the present invention, the mount is formed into substantially rectangular shape to form four inclined surfaces, and the legs forms a cross dent inwardly extending from each inclined surface. The legs are formed into columns or elongated protrusions separated from each other, extending from the mount. The support includes a circuit board on which at least an electrode and circuit conductor are formed thereon for electrical connection.
The method for manufacturing a semiconductor device according to the present invention comprises the steps of: providing a mount formed with a plurality of integrally formed legs and at least an inclined surface formed at the periphery; piling in turn on an electrode fonncd on a support, an adhesive solder paste, the mount, an adhesive solder past and a semiconductor chip to form a subassembly; and heating the subassembly to re-fuse the solder pastes and then cooling same for full setting to simultaneously bond the mount and semiconductor chip on the support. Gas produced in brazing metal is released during the heating process through at least a dent formed between the legs and the inclined surface out of the brazing metal, thus preventing trapping of bubbles therein.
The legs formed in the mount are effective to prevent slant attachment of the mount on the support with substantially uniform thickness of brazing metal between the support and
mount. In addition, the mount is firmly bonded on the support by brazing metal filled in the dent between the legs and in the flaring area between the support and the inclined surface of the mount to prevent exfoliation or detachment of the mount from the support when the semiconductor device is used under severe variation of ambient temperature. As a result, the semiconductor device can keep good electric properties during its long duration and improve yield in manufacture. A plurality of legs separated from each other provide stable attachment of the mount against its inclined condition because gas produced in brazing metal is released through the dent out of the brazing metal, thus preventing trapping of bubbles therein and enhancement of braze strength.
The above-mentioned as well as other objects of the present invention will become apparent during the course of the following detailed description and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial section view of an embodiment of the semiconductor device according to the present invention.
Fig. 2 is a partial plan view of the semiconductor device.
Fig. 3 is a side view of a mount used in the semiconductor device shown in Fig. 1.
Fig. 4 is a bottom view of the mount.
Fig. 5 is a partial section view of a second embodiment of the semiconductor device according to the present invention.
Fig. 6 is a side view of the mount used in the second embodiment shown in Fig- 5.
Fig. 7 is a bottom view of the mount used in the second embodiment shown in Fig. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figs. 1 to 4 indicate a first embodiment of the semiconductor device according to the present invention. As shown in Fig. 1, the semiconductor device comprises a circuit board 1 to form a support of ceramics such as alumina (Al2O3), a mount 2 secured on the circuit board 1, and a diode chip 3 of silicon (Si) as a semiconductor clement. Not shown but, the mount 2

We Claim
1 A semiconductor device comprising a support (1), a mount (2) secured on
said support (1) by brazing metal (9) and a semiconductor element (3) secured on
said mount (2);
said mount (2) being formed of metallic material which comprises a main body (6); at least an inclined surface (8) formed at the periphery of said main body (6) to face said support (1); and a plurality of legs (7) extending from said main body (6) inside said inclined surface (8) to form at least a dent (14) between said legs (7);
said inclined surface (8) being divergent away from said support (1);
said legs (7) being in direct contact with said support (1) to prevent inclined arrangement of said mount (2);
said mount (2) being firmly secured on said support (1) by brazing metal (9) filled in a gap which includes said dent (14) and a flaring area (13) formed between said support (1) and inclined surface (8) of said mount (2).
2 The semiconductor device of claim 1, wherein said mount (2) is formed
into substantially rectangular shape to form four inclined surfaces (8); said legs
(7) forms the dent (14) inwardly extending from each inclined surface (8).
3 The semiconductor device of claim 1, wherein said legs (7) are formed
into columns separated from each other, extending from said mount (2).
4 The semiconductor device of claim 1, wherein said legs (7) are formed
into elongated protrusions separated from each other, extending from said mount
(2).
5 The semiconductor device of claim 1, wherein said support (1) includes a
circuit board on which at least an electrode and circuit conductor are formed for
electrical connection.
6 A method for manufacturing a semiconductor device comprising the
steps of: providing a mount (2) formed with a plurality of integrally formed legs
(7) and at least an inclined surface (8) formed at the periphery;
piling in turn on an electrode (4) formed on a support (1), an adhesive solder paste, said mount (2), an adhesive solder paste and a semiconductor element (3) to form a subassembly; and heating said subassembly to re-fuse said solder pastes and then cooling same for full setting to simultaneously bond said mount (2) and semiconductor element (3) on said support (1);
said legs (7) being in direct contact with said support (1) to prevent inclined disposition of said mount (2);
said mount (2) being secured on said support (1) by brazing metal (9) filled in a gap which includes said dent (14) and a flaring area (13) formed between said support (1) and inclined surface (8) of said mount (2).
7 The method of claim 6, wherein gas produced in brazing metal (9) is
released during said heating process through at least a dent (14) formed between
said legs (7) and said inclined surface (8) out of the brazing metal (9), thus
preventing trapping of bubbles therein.
8. A semiconductor device substantially as herein described with reference to by the accompanying drawings.

Documents:

1439-del-1997-abstract.pdf

1439-del-1997-claims.pdf

1439-del-1997-complete specification (granted).pdf

1439-del-1997-corresopndence-others.pdf

1439-del-1997-corresopndence-po.pdf

1439-del-1997-description (complete).pdf

1439-del-1997-form-1.pdf

1439-del-1997-form-13.pdf

1439-del-1997-form-19.pdf

1439-del-1997-form-2.pdf

1439-del-1997-form-3.pdf

1439-del-1997-gpa.pdf

1439-del-1997-pa.pdf

1439-del-1997-petition-others.pdf

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Patent Number

193976

Indian Patent Application Number

1439/DEL/1997

PG Journal Number

36/2004

Publication Date

04-Sep-2004

Grant Date

03-Feb-2006

Date of Filing

29-May-1997

Name of Patentee

MITSUBISHI ELECTRIC CORPORATION

Applicant Address

2-3 MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO, 100, JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	HISAO TOMIZAWA	SANKEN ELECTRIC CO., LIMITED 6-3, KITANO 3-CHOME, NIIZA-SHI, SAIAMA-PREF. 352, JAPAN

PCT International Classification Number

H01L 23/48

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA