US20090297391A1

US20090297391A1 - Manufacturing method for a silver alloy bonding wire and products thereof

Info

Publication number: US20090297391A1
Application number: US12/128,097
Authority: US
Inventors: Jun-Der LEE
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-28
Filing date: 2008-05-28
Publication date: 2009-12-03

Abstract

A manufacturing method for a silver alloy bonding wire and products thereof A primary material of Ag is melted in a vacuum melting furnace, and then a plurality of secondary metal materials are added into the vacuum melting furnace and co-melted with the primary material to obtain a silver alloy ingot. The obtained silver alloy ingot is drawn to obtain a silver alloy wire. The silver alloy wire is then drawn to obtain a silver alloy bonding wire with a predetermined diameter.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention generally relates to a bonding wire used as a packaging wire, in particular, to a manufacturing method for a silver alloy boding wire and products thereof.
2. Description of Related Art
In semiconductor device packaging processes for IC, LED, SAW, a wire bonding process is often performed to electrically connect the chip to the substrate by bonding wire, which used as a signal and electrical current transmitting medium between the chip and the substrate.
The primary characteristics of a bonding wire, such as breaking load, elongation, loop, melting point, and bondability with IC chips are dependent on the materials used as the bonding wire. The performance of the packaged semiconductor device is influenced by the characteristics of the bonding wire. According to different types of chip and substrate, the adapted bonding wire has different specification.
The conventional bonding wires are usually made of pure Au material. Pure Au bonding wire has better physical properties, such as elongation and electrical conductivity. However, pure Au bonding wire inevitably leads to high cost.
Therefore, the purpose of the present invention is to solve the above mentioned problem to provide a low cost bonding wire with performance comparable to pure Au bonding wire.

SUMMARY OF THE INVENTION

The purpose of this invention is to provide a low cost silver alloy bonding wire made of a plurality of materials, capable of having performance as good as a pure Au bonding wire.
In order to obtain the above mentioned purpose, a manufacturing method for a silver alloy bonding wire and products thereof is disclosed. A primary metal material of Ag is melted in a vacuum melting furnace, and then a plurality of secondary metal materials are added into the vacuum melting furnace and co-melted with the primary metal material of Ag to obtain a silver alloy ingot consisting 90.00 to 99.99% Ag by weight. The obtained silver alloy ingot is then drawn to obtain a silver alloy wire. Finally, the obtained silver alloy wire is then drawn to obtain a silver alloy bonding wire with a predetermined diameter.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart for manufacturing silver alloy bonding wire of the present invention; and

FIG. 2 shows detailed sub-steps in the flow chart of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In cooperation with attached drawings, the technical contents and detailed description of the present invention are described thereinafter according to a preferable embodiment, being not used to limit its executing scope. Any equivalent variation and modification made according to appended claims is all covered by the claims claimed by the present invention.
Please refer to FIG. 1 and FIG. 2, which respectively are a flow chart for manufacturing silver alloy bonding wire of the present invention and a drawing showing detailed sub-steps in the flow chart of FIG. 1. Step 100, a primary material of Ag is provided.
Step 102, the material of Ag is melted in a vacuum melting furnace (step 102 a). Specific amounts of secondary metal materials of Au and Cu are added into the vacuum melting furnace (step 102 b), and co-melted with the primary material of Ag in the vacuum melting furnace to obtain a silver alloy ingot (step 102 c). The silver alloy ingot consists of 90.00-99.99% Ag, 0.0001-9.9997% Au, 0.0001-9.9997% Cu, by weight. Beside, Specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material and secondary materials in the vacuum melting furnace to obtain a silver alloy ingot further consisting 0.0001-9.9997% Be and 0.0001-9.9997% Al, by weight.
Subsequently, continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with diameter of 4-8 mm (step 102 d). The silver alloy wire is rewired by a reeling machine (step 102 e) and then composition analysis (102 f) is performed on the silver alloy wire to check if the obtained composition meets the requirement. Step 104, a drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 4-8 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 3 mm or smaller than 3 mm (step 104 a). The silver alloy wire with a diameter of 3 mm or smaller than 3 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a predetermined diameter of 1 mm or smaller than 1 mm (step 104 b). The silver alloy wire with diameter 1 mm or smaller than 1 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.5 mm or smaller than 0.5 mm (step 104 c). Then the silver alloy wire with a diameter of 0.5 mm or smaller than 0.5 mm is sequentially drawn by the second thin drawing machine (step 104 d), a very thin drawing machine (step 104 e) and an ultra thin drawing machine (step 104 f) to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) to 0.010 mm (0.40 mil).
Step 106, the surface of silver alloy bonding wire is cleaned.
Step 108, the silver alloy bonding wire is annealed to ensure a final product with desirable physical properties of breaking load and elongation.
The silver alloy bonding wire can be applied to packaging process of IC, LED and SAW.
The invention is more detailed described by seven embodiments below:

Embodiment 1

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 98.659 wt. % Ag, 0.50 wt. % Au, 0.84 wt. % Cu, 0.0008 wt. % Be and 0.0002 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 6 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 3 mm. The silver alloy wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 1 mm. The silver alloy wire with a diameter of 1 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.5 mm. Then the silver alloy wire with a diameter of 0.5 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 2

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 99.99 wt. % Ag, 0.005 wt. % Au, 0.003 wt. % Cu, 0.001 wt. % Be and 0.001 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 6 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 3 mm. The silver alloy wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.8 mm. The silver alloy wire with a diameter of 0.8 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 3

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 95 wt. % Ag, 1.25 wt. % Au, 1.25 wt. % Cu, 1.25 wt. % Be and 1.25 wt. % Al. Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 6 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 3 mm. The silver alloy wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.9 mm. The silver alloy wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 4

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 90 wt. % Ag, 0.0001 wt. % Au, 0.0001 wt. % Cu, 9.9997 wt. % Be and 0.0001 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 4 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 4 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 2.5 mm. The silver alloy wire with a diameter of 2.5 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.9 mm. The silver alloy wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 5

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 90 wt. % Ag, 9.9997 wt. % Au, 0.0001 wt. % Cu, 0.0001 wt. % Be and 0.0001 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 8 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 8 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 2 mm. The silver alloy wire with a diameter of 2 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.9 mm. The silver alloy wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 6

A primary material of Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 90 wt. % Ag, 0.0001 wt. % Au, 0.0001 wt. % Cu, 0.0001 wt. % Be and 9.9997 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 6 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 3 mm. The silver alloy wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.9 mm. The silver alloy wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.

Embodiment 7

A primary material with Ag is provided and is melted in a vacuum melting furnace. Then, specific amounts of secondary metal materials of Au and Cu and specific amounts of trace metal materials of Be and Al are added into the vacuum melting furnace, and co-melted with the primary material in the vacuum melting furnace to obtain a silver alloy ingot. The silver alloy ingot consists of: 90 wt. % Ag, 0.0001 wt. % Au, 9.9997 wt. % Cu, 0.0001 wt. % Be and 0.0001 wt. % Al.
Continuous casting process is performed on the silver alloy ingot to draw to obtain a silver alloy wire with a diameter of 6 mm. The silver alloy wire is rewired by a reeling machine and then composition analysis is performed on the silver alloy wire to check if the obtained composition meets the requirement.
A drawing process is performed on the silver alloy wire; the obtained silver alloy wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a silver alloy wire with a diameter of 2 mm. The silver alloy wire with a diameter of 2 mm is drawn by a second thick drawing machine to obtain a silver alloy wire with a diameter of 0.9 mm. The silver alloy wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a silver alloy wire with a diameter of 0.45 mm. Then the silver alloy wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin silver alloy bonding wire with a predetermined diameter of 0.0508 mm to 0.010 mm.
Finally, the surface of silver alloy bonding wire is cleaned and is annealed.
While the invention is described in by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, the aim is to cover all modifications, alternatives and equivalents falling within the spirit and scope of the invention as defined by the appended claims.

Claims

1. A manufacturing method for a silver alloy bonding wire, comprising:

a) providing a primary material of Ag;

b) melting the primary material in a vacuum melting furnace, adding a plurality of secondary metal materials of Au and Cu into the vacuum melting furnace and co-melting with the primary material in the vacuum melting furnace to obtain a silver alloy ingot;

c) drawing the silver alloy ingot to obtain a silver alloy wire; and

d) drawing the silver alloy wire to obtain a silver alloy bonding wire with a predetermined diameter.

2. The manufacturing method according to claim 1, wherein the weight percent of Ag in step a) is 90.00%˜99.99%.

3. The manufacturing method according to claim 2, wherein the weight percent of Au in step b) is 0.0001%˜9.9997%.

4. The manufacturing method according to claim 3, wherein the weight percent of Cu in step b) is 0.0001%˜9.9997%.

5. The manufacturing method according to claim 4, wherein a plurality of trace metal materials of Be and Al are added into the vacuum melting furnace and co-melted in step b).

6. The manufacturing method according to claim 5, wherein the weight percent of Be in step b) is 0.0001%˜9.9997%.

7. The manufacturing method according to claim 6, wherein the weight percent of Al in step b) is 0.0001%˜9.9997%.

8. The manufacturing method according to claim 7, wherein the surface of the silver alloy bonding wire is cleaned and is annealed after step d).

9. A silver alloy bonding wire, comprising:

90.00-99.99 wt. % Ag;

0.0001˜9.9997 wt. % Au; and

0.0001˜9.9997 wt. % Cu.

10. The silver alloy bonding wire according to claim 9, further comprises 0.0001%˜9.9997% wt. Be.

11. The silver alloy bonding wire according to claim 10, further comprises 0.0001%˜9.9997% wt. Al.