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Leadframe having a mold inflow groove and method for making

Imported: 23 Feb '17 | Published: 22 Oct '02

Hyung Ju Lee

USPTO - Utility Patents

Abstract

A leadframe having a mold inflow groove provides for an increase in the number of inner leads for connecting with outer electrical sources and accurate singulation. A molding compound is introduced through mold inflow grooves positioned at both sides of a tie bar into the cavity so that no culls remain on the tie bar after molding. The end of a runner of the mold die is positioned at a sufficient distance away from the molding area of the leadframe to allow the top and bottom surfaces of the tie bar to remain free of culls.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of one embodiment of a leadframe of the present invention with shading to indicate void areas of the leadframe.

FIG. 2 is a cross-section of the leadframe of FIG. 1 after a mold die and semiconductor chip have been secured to the leadframe.

FIG. 3 is a top plan view taken along the

3

3 line of FIG. 4 showing the mold flow path into the cavity formed by the mold die and leadframe.

FIG. 4 is a cross-section of the leadframe of FIG. 3 taken along the line

4

4, showing the mold flowing from the runner into the mold-inflow groove and then into the cavity surrounding the semiconductor chip and leadframe.

FIG. 5 is a side view of an exemplary singulation step for the leadframe of FIG. 1 after the molding process has been completed.

FIG. 6 is top plan view of a corner of the leadframe of FIG. 3 after a mold die has been removed during the molding process.

Claims

1. A leadframe, comprising:

2. The leadframe according to claim 1, wherein said mold inflow groove allows a mold compound to flow on both lateral sides of a respective tie bar at a point on said tie bar where a die/runner border crosses said tie bar.

3. The leadframe according to claim 2, wherein an upper side of said mold compound and an upper surface of said respective tie bar are in a same plane after molding.

4. The leadframe according to claim 2, wherein a side of said mold inflow groove adjacent to said respective tie bar is spaced apart from said die/runner border in a direction along said tie bar.

5. The leadframe according to claim 1, wherein a mold inflow groove is formed at each corner of said frame body.

6. The leadframe according to claim 1, wherein said mold inflow groove allows said leadframe to be level with a singulation die when said leadframe is placed on said singulation die.

7. A leadframe for a semiconductor device, comprising:

8. The leadframe according to claim 7, wherein an upper side of said mold compound and an upper surface of said attaching means are in a same plane after molding.

9. The leadframe according to claim 7, wherein a side of said receiving means adjacent to said attaching means is spaced apart from said die/runner border in a direction along said attaching means.

10. The leadframe according to claim 7, wherein one of said receiving means is formed at each comer of said leadframe.

11. The leadframe according to claim 7, wherein said receiving means allows said leadframe to be level with a singulation die when said leadframe is placed on said singulation die.

12. The leadframe according to claim 7, wherein said receiving means is divided into two domains by said attaching means.

13. A semiconductor device, comprising:

14. The semiconductor device according to claim 13, wherein said mold inflow groove allows said mold compound to flow on both lateral sides of said tie bar at a point on said tie bar where a die/runner border crosses said tie bar.

15. The semiconductor device according to claim 14, wherein an upper side of said mold compound and an upper surface of said tie bar are in the same plane after said molding process is completed.

16. The semiconductor device according to claim 14, wherein a side of said mold inflow groove adjacent to said tie bar is spaced apart from said die/runner border in a direction along said tie bar.

17. The semiconductor device according to claim 13, wherein a mold inflow groove is formed at each corner of said leadframe.

18. The semiconductor device according to claim 13, wherein said mold inflow groove allows said leadframe to be level with a singulation die when said leadframe is placed on said singulation die.

19. The semiconductor device according to claim 13, wherein said mold inflow groove is divided into two domains by said attaching means.