Semiconductor package and lead frame therefor

• US 20060138615A1
• Filed: 12/21/2005
• Published: 06/29/2006
• Est. Priority Date: 12/24/2004
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Sato, Takashi, Shirasaka, Kenichi
• Granted Patent: US 7,397,112 B2
• Time in Patent Office: Days
• US Class Current: 257/666
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• 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 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/49548 Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/49582 Metallic layers on lead frames
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/207 Diameter ranges

Abstract

A lead frame adapted to a semiconductor package, which is enclosed in a molded resin body and is connected with a board, is formed by processing a thin metal plate so as to include a stage for mounting a semiconductor chip thereon, a plurality of leads arranged to encompass the stage, and a plurality of lead interconnecting members (or dam bars) for interconnecting the leads together. At least one recess, which is of a circular shape or a non-circular shape, is formed on the backside of the lead (or the lead interconnecting member), which is substantially arranged in the same plane with a terminal surface of the molded resin body. Due to the formation of the recess that is subjected to plating, it is possible to increase the joining strength between the lead and solder; hence, it is possible to improve reliability regarding electric connection between the semiconductor package and board.

Claims

1. A lead frame that is adapted to a semiconductor package enclosed in a molded resin body and that is formed by processing a thin metal plate, said lead frame comprising:

a stage on which a semiconductor chip is mounted;

a plurality of leads that are arranged to encompass the stage and that are partially exposed to a terminal surface lying in a thickness direction of the molded resin body; and

a plurality of lead interconnecting members for connecting the leads together,

wherein at least one recess is formed with respect to the terminal surface of the molded resin body.

2. A lead frame according to claim 1, wherein at least one through hole is formed to run through the lead in its thickness direction at a prescribed position allowing a cutting line, by which the leads are electrically isolated from each other, to pass therethrough.

3. A lead frame according to claim 1, wherein at least one through hole is formed to run through the lead interconnecting member in its thickness direction at a prescribed position allowing a cutting line, by which the leads are electrically isolated from each other, to pass therethrough.

4. A lead frame according to claim 3, wherein the through hole is enlarged in a direction for alignment of a prescribed number of the leads.

5. A semiconductor package enclosed in a molded resin body and encapsulating a plurality of leads, which are partially exposed to a terminal surface lying in a thickness direction of the molded resin body, wherein at least one recess is formed at a prescribed position of the lead that is exposed to the terminal surface of the molded resin body.

6. A semiconductor package according to claim 5, wherein the lead is exposed to a side surface adjacent the terminal surface of the molded resin body, and wherein the recess is opened outwardly from the side surface of the molded resin body.

7. A semiconductor package according to claim 5, wherein a secondary recess allowing a cutting line, by which the lead is subjected to cutting, to pass therethrough is formed in addition to the at least one recess on a backside of the lead in its longitudinal direction.

8. A semiconductor package according to claim 5, wherein the at least one recess is formed in a non-circular shape on a backside of the lead.

9. A semiconductor package according to claim 5, wherein a secondary recess having a non-circular shape allowing a cutting line, by which the lead is subjected to cutting, to pass therethrough is formed in addition to the at least one recess that is formed in a non-circular shape on a backside of the lead in its longitudinal direction.