Bonding wire

Patent metadata

Field	Value
Publication number	US-12290883-B2
Application number	US-202318855536-A
Country	US
Kind code	B2
Filing date	Jun 27, 2023
Priority date	May 30, 2023
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

There is provided a novel alloy-coated Cu bonding wire that achieves a favorable FAB shape and also a favorable initial bondability of a 2nd bonding part including adhesion of the 2nd bonding part, and that reduces a galvanic corrosion in a high-temperature environment to achieve a favorable bond reliability of the 2nd bonding part. The alloy-coated Cu bonding wire includes a core material of Cu or Cu alloy, and a coating layer having a total concentration of Pd and Ni of 90 atomic % or more formed on a surface of the core material. The bonding wire is characterized in that:
in a concentration profile in a depth direction of the wire obtained by performing measurement using Auger electron spectroscopy (AES) so that the number of measurement points in the depth direction is 50 or more for the coating layer, a thickness of the coating layer is 10 nm or more and 130 nm or less, an average value X is 0.1 or more and 35.0 or less, the average value X being defined as an average value of a ratio of a Pd concentration C Pd (atomic %) to an Ni concentration C Ni (atomic %), C Pd /C Ni , for all measurement points in the coating layer, the total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.3X or less is 50% or more relative to the total number of measurement points in the coating layer, and the bonding wire satisfies the following condition (A): (A) the bonding wire contains one or more elements selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Zn, Zr, Nb, Mo, Ru, Rh, Sn, Ta, W, Os, Ir, Pt, Au and Bi (hereinafter referred to as “first additive element”), and the total concentration of the first additive element relative to the entire wire is 5 ppm by mass or more and 450 ppm by mass or less.

First claim

The invention claimed is:

1. A bonding wire comprising:
a core material of Cu or Cu alloy; and
a coating layer having a total concentration of Pd and Ni of 90 atomic % or more formed on a surface of the core material, wherein
in a concentration profile in a depth direction of the bonding wire obtained by performing measurement using Auger electron spectroscopy (AES) so that the number of measurement points in the depth direction is 50 or more for the coating layer,
a thickness of the coating layer is 10 nm or more and 130 nm or less,
an average value X is 0.1 or more and 35.0 or less where X is defined as an average value of a ratio of a Pd concentration C Pd (atomic %) to an Ni concentration C Ni (atomic %), C Pd /C Ni , for all measurement points in the coating layer,
a total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.3X or less is 50% or more relative to a total number of measurement points in the coating layer, and
the bonding wire satisfies the following condition (A):
(A) the bonding wire contains one or more elements (hereinafter referred to as a “first additive element”) selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Zn, Zr, Nb, Mo, Ru, Rh, Sn, Ta, W, Os, Ir, Pt, Au and Bi, and a total concentration of the first additive element relative to the entire bonding wire is 5 ppm by mass or more and 450 ppm by mass or less.

2. The bonding wire according to claim 1 , wherein the total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.2X or less is 50% or more relative to the total number of the measurement points in the coating layer.

3. The bonding wire according to claim 1 , wherein when linearly approximating C Pd or C Ni by the method of least squares for all measurement points in the coating layer to obtain an approximate straight line, a difference between a maximum value and a minimum value of the obtained approximate straight line in a depth range of the coating layer is 20 atomic % or less.

4. The bonding wire according to claim 1 , wherein the concentration profile in the depth direction of the bonding wire is obtained by performing the measurement using AES under the following <Condition>while digging down the bonding wire from its surface in the depth direction by Ar sputtering:
<Condition>a center of width of a measuring surface is aligned with a center of width of the bonding wire, the width of the measuring surface is 5% or more and 15% or less of a diameter of the bonding wire, and a length of the measuring surface is five times the width of the measuring surface.

5. The bonding wire according to claim 1 , wherein
the bonding wire contains one or more elements selected from the group consisting of B, P and Mg (hereinafter referred to as a “second additive element”), and
a total concentration of the second additive element is 1 ppm by mass or more and 100 ppm by mass or less relative to the entire bonding wire.

6. The bonding wire according to claim 1 , wherein
the bonding wire contains one or more elements selected from the group consisting of Se, Te, As and Sb (hereinafter referred to as a “third additive element”), and
a total concentration of the third additive element is 1 ppm by mass or more and 100 ppm by mass or less relative to the entire bonding wire.

7. The bonding wire according to claim 1 , wherein
the bonding wire contains one or more elements selected from the group consisting of Ga and Ge (hereinafter referred to as a “fourth additive element”), and
a total concentration of the fourth additive element is 0.011% by mass or more and 1.5% by mass or less relative to the entire bonding wire.

8. The bonding wire according to claim 1 , wherein
the bonding wire contains one or more elements selected from the group consisting of In and Ag (hereinafter referred to as a “fifth additive element”), and
a total concentration of the fifth additive element is 1 ppm by mass or more and 500 ppm by mass or less relative to the entire bonding wire.

9. A bonding wire comprising:
a core material of Cu or Cu alloy; and
a coating layer having a total concentration of Pd and Ni of 90 atomic % or more formed on a surface of the core material, wherein
in a concentration profile in a depth direction of the bonding wire obtained by performing measurement using Auger electron spectroscopy (AES) so that the number of measurement points in the depth direction is 50 or more for the coating layer,
a thickness of the coating layer is 10 nm or more and 130 nm or less,
an average value X is 0.1 or more and 35.0 or less where X is defined as an average value of a ratio of a Pd concentration C Pd (atomic %) to an Ni concentration C Ni (atomic %), C Pd /C Ni , for all measurement points in the coating layer,
a total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.3X or less is 50% or more relative to a total number of measurement points in the coating layer, and
the bonding wire satisfies the following conditions (A) and (B):
(A) the bonding wire contains one or more elements (hereinafter referred to as a “first additive element”) selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Zn, Zr, Nb, Mo, Ru, Rh, Sn, Ta, W, Os, Ir, Pt, Au and Bi, and the total concentration of the first additive element relative to the entire bonding wire (provided that, the concentration of Au is the concentration thereof in the core material part) is 5 ppm by mass or more and 450 ppm by mass or less; and
(B) the bonding wire contains Au at a surface of the wire, and a concentration of Au relative to the entire wire is 0.5% by mass or less.

10. The bonding wire according to claim 9 , wherein the total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.2X or less is 50% or more relative to the total number of the measurement points in the coating layer.

11. The bonding wire according to claim 9 , wherein when linearly approximating C Pd or C Ni by the method of least squares for all measurement points in the coating layer to obtain an approximate straight line, a difference between a maximum value and a minimum value of the obtained approximate straight line in a depth range of the coating layer is 20 atomic % or less.

12. The bonding wire according to claim 9 , wherein the concentration profile in the depth direction of the bonding wire is obtained by performing the measurement using AES under the following <Condition>while digging down the bonding wire from its surface in the depth direction by Ar sputtering:
<Condition>a center of width of a measuring surface is aligned with a center of width of the bonding wire, the width of the measuring surface is 5% or more and 15% or less of a diameter of the bonding wire, and a length of the measuring surface is five times the width of the measuring surface.

13. The bonding wire according to claim 9 , wherein
the bonding wire contains one or more elements selected from the group consisting of B, P and Mg (hereinafter referred to as a “second additive element”), and
a total concentration of the second additive element is 1 ppm by mass or more and 100 ppm by mass or less relative to the entire bonding wire.

14. The bonding wire according to claim 9 , wherein
the bonding wire contains one or more elements selected from the group consisting of Se, Te, As and Sb (hereinafter referred to as a “third additive element”), and
a total concentration of the third additive element is 1 ppm by mass or more and 100 ppm by mass or less relative to the

Assignees

• Nippon Micrometal Corp

Inventors

• Oda Daizo
• Eto Motoki
• Oishi Ryo

Classifications

• H10W72/01515

  Forming coatings · CPC title

• H10W72/522

  Multilayered bond wires, e.g. having a coating concentric around a core · CPC title

• H10W72/5524

  comprising aluminium [Al] · CPC title

• H10W90/756

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

• H10W72/59

  Bond pads specially adapted therefor · CPC title