Electrode connection structure, lead frame, and method for forming electrode connection structure

Patent metadata

Field	Value
Publication number	US-2019103341-A1
Application number	US-201716083389-A
Country	US
Kind code	A1
Filing date	Mar 7, 2017
Priority date	Mar 10, 2016
Publication date	Apr 4, 2019
Grant date	—

Abstract

[Problem] To provide an electrode connection structure and the like in which a plurality of elongated leads are arranged in parallel and a longitudinal side surface of each lead is connected to an electrode by plating treatment with high quality.
[Solution] An electrode connection structure in which a semiconductor chip 12 electrode and/or a substrate electrode is connected to a plurality of elongated leads 11 of a lead frame 10 by plating. The plurality of elongated leads 11 of the lead frame 10 are arranged in parallel, and a longitudinal side surface of each lead 11 is connected to the semiconductor chip 12 electrode and/or the substrate electrode by plating. At a connection portion of a first connection surface 13 of the semiconductor chip 12 electrode and/or the substrate electrode, the first connection surface 13 being connected to the leads 11, and a second connection surface 14 in the longitudinal side surface of each lead 11, the second connection surface 14 being connected to the first connection surface 13, a distance between the first connection surface 13 and the second connection surface 14 continuously increases from an edge portion 15 of the second connection surface 14, the edge portion 15 being in contact with the first connection surface 13, toward an outer portion 16 of the second connection surface 14.

First claim

1 . An electrode connection structure comprising:
an electrode of an electronic device or a substrate; and a lead frame containing a plurality of leads being connected to said electrode by plating, wherein the plurality of leads in the lead frame are elongated and arranged in parallel, and a longitudinal side surface of each lead is connected to the electrode by plating, and at a first connection portion of a first connection surface of the electrode, the first connection surface being connected to the leads, and a second connection surface in the longitudinal side surface of each lead, the second connection surface being connected to the first connection surface, a first distance between the first connection surface and the second connection surface continuously increases from an edge portion of the second connection surface, the edge portion being in contact with the first connection surface, toward an outer portion of the second connection surface.

2 . The electrode connection structure according to claim 1 , wherein:
each lead is reduced in thickness from the edge portion of the second connection surface toward the outer portion of the second connection surface.

3 . The electrode connection structure according to claim 2 , wherein:
the edge portion is formed at a longitudinal center portion of the second connection surface.

4 . The electrode connection structure according to claim 1 , wherein:
the edge portion comprises a plurality of transverse edge portions that are formed at a predetermined interval in a transverse direction of the second connection surface, and a transverse concave groove-like gap is formed between each pair of adjacent transverse edge portions, the transverse gap penetrating in a transverse direction of the second connection surface.

5 . The electrode connection structure according to claim 1 , wherein:
a longitudinal concave groove-like gap that is continuous or discontinuous in a longitudinal direction of the second connection surface is formed.

6 . The electrode connection structure according to claim 1 , wherein:
at a second connection portion of a third connection surface on a back surface side of the second connection surface and a fourth connection surface of the electrode, the fourth connection surface being connected to the third connection surface, a second distance between the fourth connection surface and the third connection surface continuously increases from a second edge portion of the third connection surface, the second edge portion being in contact with the fourth connection surface, toward a second outer portion of the third connection surface.

7 . An electrode connection structure comprising:
an electrode of an electronic device or a substrate; and a lead frame containing a plurality of leads being connected to said electrode by plating, wherein: the plurality of leads in the lead frame are elongated and arranged in parallel, and a longitudinal side surface of each lead is connected to the electrode by plating, and at a connection portion of a first connection surface of the electrode, the first connection surface being connected to the leads, and a second connection surface in the longitudinal side surface of each lead, the second connection surface being connected to the first connection surface, a plurality of edge portions each in contact with the first connection surface are formed at a predetermined interval in a transverse direction of the second connection surface, and a concave groove-like gap is formed between each pair of adjacent edge portions, the gap penetrating in a transverse direction of the second connection surface.

8 . The electrode connection structure according to claim 1 , wherein:
the connection by plating is made by plating with a metal or an alloy having a melting point of 700° C. or higher.

9 . The electrode connection structure according to claim 8 , wherein:
the metal or the alloy is nickel or a nickel alloy.

10 . The electrode connection structure according to claim 1 , wherein:
an angle between the electrode and the longitudinal side surface of each lead at the edge portion of each lead is 3 to 15 degrees.

11 . A method for forming the electrode connection structure according to claim 3 , wherein:
the edge portion is formed by press working or etching processing.

12 . A lead frame connected to an electrode of an electronic device or a substrate by plating, comprising:
a plurality of leads being elongated and arranged in parallel; and an edge portion in contact with the electrode is formed on a longitudinal side surface of each lead joined to the electrode.

13 . The lead frame according to claim 12 , wherein:
each lead is reduced in thickness from the edge portion toward an outer portion of a connection surface including the edge portion.

14 . The lead frame according to claim 13 , wherein:
the edge portion is formed at a center portion of the connection surface in a longitudinal direction.

15 . The lead frame according to claim 12 , wherein:
the edge portion comprises a plurality of transverse edge portions that are formed at a predetermined interval in a transverse direction of the connection surface, and a transverse concave groove-like gap is formed between each pair of adjacent transverse edge portions, the transverse gap penetrating in a transverse direction of the connection surface.

16 . The lead frame according to claim 12 , wherein:
a longitudinal concave groove-like gap that is continuous or discontinuous in a longitudinal direction of the connection surface is formed.

17 . The lead frame according to claim 12 , wherein:
another edge portion is formed on the longitudinal side surface of each lead on a back surface side of the connection surface on which the edge portion is formed.

18 . The lead frame according to claim 12 , wherein:
the edge portion of each lead is formed at an angle of 3 to 15 degrees with respect to a surface of the electrode, the surface being joined to the edge portion.

19 . A method for forming an electrode connection structure in which an electrode of an electronic device or a substrate is connected to a lead of a lead frame, comprising:
providing the lead frame including a plurality of leads being elongated and arranged in parallel, and an edge portion on a longitudinal side surface of each lead; and applying ultrasonic vibration in a state where the electrode is in contact with the edge portion of each lead to buckle a tip of the edge portion, whereby the electrode is ultrasonically joined to each lead.

20 . The electrode connection structure forming method according to claim 19 , wherein:
a plating joining process is performed in a state where the electrode is temporarily joined to each lead of the lead frame by the ultrasonic joining.

21 . The electrode connection structure forming method according to claim 19 , wherein:
an angle between the edge portion of each lead and the electrode is 3 to 15 degrees.

22 . The electrode connection structure forming method according to claim 19 , wherein:
a buckling width of a tip of the edge portion is 1 to 50 μm.

23 . The electrode connection structure forming method according to claim 19 , wherein:
a frequency of the ultrasonic vibration is 15 to 150 kHz.

Assignees

• Univ Waseda
• Mitsui High Tec

Inventors

• Tatsumi Kohei
• Ueda Kazutoshi
• Sato Nobuaki
• Shimizu Koji

Classifications

• H10W90/766

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W72/07553

  changes in shapes · CPC title

• H10W72/07251

  characterised by changes in properties of the bump connectors during connecting · CPC title

• H10W72/533

  Cross-sectional shape · CPC title

• H10W72/531

  Shapes of wire connectors · CPC title