JPH01294474A - Package of bonding wire - Google Patents

Abstract

PURPOSE:To prevent oxidation over a long period of time, by sealing both of or either one of an oxygen adsorbent and a moisture absorbent in a bag. CONSTITUTION:A copper wire 1 is wound around a cylindrical spool 2 made of aluminum to be received in a spool case 3 along with the spool 2. The spool case 3 is hermetically sealed in a bag 6 constituted of a plastic film rich in a gas barrier property used in a usual vacuum package or a multilayer structure thereof. Further, an oxygen adsorbent 4 and a moisture absorbent 5 are together enclosed in the bag 6 and, further, said bag 6 is sealed with argon gas as the gas inert to copper. In the package of the copper wire 1 thus constituted, the open air becomes hard to penetrate in the bag 6 and the oxygen and moisture in the air remaining in the bag 6 are absorbed by the oxygen adsorbent 4 and the moisture absorbent 5 to be prevented from the contact with the surface of the copper wire 1. Therefore, the surface oxidation of the copper wire 1 can be prevented over a long period of time.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a packaging body for bonding wires for devices such as semiconductors, and in particular improves bonding wires made of copper or copper alloy to prevent surface oxidation. The present invention relates to a bonding wire package.

[Prior Art] Conventionally, gold wires have been most commonly used as bonding wires for devices such as semiconductors, but due to the trend toward metallization, various base metal wires are being used. among them,
Copper wires or copper alloy wires, which have excellent bonding properties and high-temperature properties, are beginning to be put into practical use.

However, copper wire or copper alloy wire has the drawback that it is more easily oxidized by oxygen in the air than conventional gold wire, and oxidation is particularly likely to be accelerated in an atmosphere containing moisture. Therefore, preventing oxidation of the surface during storage is an important issue.

Conventionally, for example, copper wire was wound around a spool, the spool was housed in a spool case, and then sealed in a synthetic resin film bag, and the inside of the bag was either evacuated or filled with inert gas. The copper wires were then stored or transported.

[Problem M to be solved by the invention] However, in the conventional packaging body described above, it is difficult to create a complete vacuum inside the bag, and even when inert gas is sealed inside the bag, air is left inside the bag. may remain. Also,
It is difficult for the bag mouth body to maintain perfect sealing over a long period of time, and air gradually enters the bag. Therefore, there was a problem in that the surface of the copper wire was gradually oxidized.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bonding wire package that can prevent oxidation over a long period of time.

[Means for Solving the Problems] In order to achieve the above object, the present invention is characterized in that both or one of an oxygen adsorbent and a moisture absorbent are enclosed in a bag.

In this case, it is desirable to create a vacuum inside the bag.

Further, a gas inert to copper may be sealed in the bag.

Further, the gas inert to copper is preferably an inert gas such as argon gas or nitrogen gas.

Furthermore, the gas may be a mixture of an inert gas and hydrogen gas or a mixture of nitrogen gas and hydrogen gas.

[Function] In the present invention, oxygen and/or moisture in the air in the bag is absorbed by the oxygen adsorbent or moisture absorbent, and the oxygen and/or moisture is absorbed onto the surface of the bonding wire. You won't be able to touch it.

In addition, when the inside of the bag is evacuated, the small amount of acid, element, and/or moisture in the air remaining inside the bag can be quickly absorbed into the oxygen adsorbent and/or moisture absorbent. On the other hand, absorb.

Furthermore, when a gas inert to copper is sealed in the bag, the oxygen and/or moisture remaining in the bag can be absorbed into the oxygen adsorbent and/or moisture absorbent in a short period of time. On the other hand, it absorbs air, and the pressure of the gas inside the bag makes it difficult for air to enter from the outside.

In addition, when hydrogen is mixed with an inert gas such as argon gas or nitrogen gas, the hydrogen that reaches the bonding wire surface significantly reduces the oxygen partial pressure on the bonding wire surface, and the oxygen is transferred to the bonding wire surface. It suppresses the adsorption of oxygen atoms and the bonding between oxygen atoms and metal atoms.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. However, this example is, of course, merely to show an example embodying the invention, and is not intended to limit the technical scope of the invention.

In FIGS. 1 and 2, 1 is a copper wire with a diameter of 25μ, which is used as a bonding wire for devices such as semiconductors, and this copper wire 1 is attached to a cylindrical spool 2 made of aluminum.
wrapped around. The copper wire l is housed together with the spool 2 in a spool case 3 made of polyvinyl chloride. The spool case 3 includes a lower portion 13a that fits into the inner peripheral surface of the spool 2 from below, and an upper lid 3b that fits into the inner peripheral surface from above. This spool case 3 is sealed with a bag 6. This bag 6 is made of a plastic film with high gas barrier properties used in ordinary vacuum packaging or a multilayer structure thereof.
For example, it is composed of a two-layer laminate film of polyamide and polypropylene, or a three-layer laminate film of polyvinyl chloride, polypropylene, and polyethylene. Further, inside the bag 6, an oxygen adsorbent 4 and a moisture absorbent 5 are enclosed. As the oxygen adsorbent 4, a material that easily combines with oxygen, such as iron or rare earth elements, is used, and as the moisture absorbent 5, silica gel or the like is used. Furthermore, argon gas 7 is sealed in the bag 6 as a gas inert to copper. To enclose the argon gas 7 in the bag 6, the inside of the bag 6 is evacuated, and then the bag 6 is filled with argon gas and sealed.

In the package in which the copper wire l is sealed in the bag 6 as described above, the oxygen in the air remaining in the bag 6 is absorbed by the oxygen adsorbent 4.
The moisture in the air is absorbed by the moisture absorbent 5. At this time, since the inside of the bag 6 is evacuated and then filled with argon gas 7, only a small amount of oxygen and moisture remain in the bag 6, and the oxygen and moisture are absorbed into the oxygen adsorbent in a short time. 4 and the moisture absorbent 5. Furthermore, the pressure of the argon gas 7 within the bag 6 makes it difficult for outside air to enter the bag 6.

Therefore, according to the package of copper wire 1 as described above, it becomes difficult for outside air to enter into the bag 6, and the oxygen and moisture in the air remaining in the bag 6 are absorbed by the oxygen adsorbent 4 and the moisture absorbent 5. It is absorbed by the copper wire and no longer touches the surface of the copper wire. Therefore, oxidation of the surface of the copper wire 1 can be prevented for a long period of time.

In the above embodiment, argon gas was used as the gas sealed in the bag 6, but other inert gases such as helium gas may be used, or gases inert to copper such as nitrogen gas. You can. Further, the gas may be a mixture of an inert gas and hydrogen, or a mixture of hydrogen and a gas inert to copper, such as nitrogen gas.

Moreover, although both the oxygen adsorbent 4 and the moisture absorbent 5 are enclosed in the bag 6, either the oxygen adsorbent 4 or the moisture absorbent 5 may be enclosed.

[Experimental Example] Next, an experiment was conducted to investigate the effect of the package of copper wire 1 as described above.

First, for the bag 6, a laminate film having a three-layer structure of polyvinyl chloride, polypropylene, and polyethylene and a total thickness of near 0 μm was used.

Then, the spool case 3 containing the spool 2 wound with the copper wire 1 is packed in an air pack, a vacuum bag, an argon gas or nitrogen gas pack, or after mixing hydrogen gas into the gas, the packaging example 1 of the present invention is carried out. -12, and for comparison, air pack, vacuum pack, argon gas or nitrogen gas bag, or hydrogen gas mixed in the above gas without enclosing oxygen adsorbent and/or moisture absorber, and then pack. Package examples 1-6 were manufactured.

Next, in order to investigate the effects of these packages, the packages were left for about 1 month and about 3 months, and the amount of surface oxidation and bonding properties of the copper wires 1 were investigated. The amount of surface oxidation was determined using an Auger M 1cro probe.
The irradiation time required for the oxygen intensity to reach the pack ground level is measured by Ar bombardment, and the bonding performance is measured by performing ball-stitch bonding using these copper wires on an Ag-plated lead frame, and determining whether the wires will peel off by a pull test. We investigated the rate at which this occurs. These results are shown in Table 1.

From the results shown in Table 1 below, it can be seen that in comparison packages and package examples 1 to 6 that do not contain an oxygen adsorbent and/or moisture absorbent, the amount of surface oxidation and the wire peeling rate are higher than that of thick copper. On the other hand, in package example 1-10 of the present invention, the amount of surface oxidation was extremely small and the wire peeling rate was 0%, and the oxygen adsorbent and / It can be seen that the inclusion of the moisture absorbent greatly suppresses oxidation on the surface of the copper wire 1 and significantly contributes to maintaining the cleanliness of the surface of the copper wire 1.

Effects of the invention As is clear from the above explanation, according to this invention,
Oxygen and/or moisture in the air within the bag are absorbed by the oxygen adsorbent or moisture absorbent, and the oxygen and/or moisture no longer come into contact with the surface of the bonding wire. Therefore, bonding wires made of copper or copper alloy, whose surfaces are easily oxidized by oxygen in the air, can be stored for a long period of time.

In addition, when the inside of the bag is evacuated, the amount of oxygen and moisture remaining in the bag becomes extremely small, so the oxygen and/or moisture is absorbed into both the oxygen adsorbent and the moisture absorbent in a short period of time. Alternatively, either one of them can be absorbed, and in this case, the absorption performance of both or either of the oxygen adsorbent and the moisture absorbent will be less deteriorated. Therefore, oxygen and/or moisture in the air entering from the outside can be absorbed for a long period of time, and oxidation of the bonding wire can be prevented for a long period of time.

Furthermore, if the inside of the bag is evacuated and then filled with gas that is inert to copper, the oxygen and/or moisture remaining in the bag can be removed in a short period of time. Both or either of the oxygen adsorbent and the moisture absorbent can be absorbed, and the pressure of the gas inside the bag makes it difficult for air to enter from the outside. Therefore, also in this case, oxidation of the bonding wire can be prevented for a long period of time.

In addition, when the gas is an inert gas such as argon gas or nitrogen gas, the surface of the bonding wire is protected by the inert gas or nitrogen gas, so oxidation of the bonding wire can be prevented for a long time in this case as well. be able to.

Furthermore, when the gas is a mixture of hydrogen and an inert gas such as argon gas, or a mixture of nitrogen gas and hydrogen, the hydrogen that reaches the bonding wire surface significantly increases the oxygen partial pressure on the bonding wire surface. Since the adsorption of oxygen to the surface of the bonding wire and the bonding between oxygen atoms and metal atoms are suppressed by reducing the amount of oxygen, oxidation of the bonding wire can be prevented for a long period of time in this case as well.

[Brief explanation of the drawing]

FIG. 1 illustrates the packaging form of the bonding wire of the present invention, and FIG. 1(a) is a plan view of the spool case;
FIG. 1(b) is an exploded side view showing the spool case, the spool, wire, oxygen adsorbent and moisture absorbent contained therein, and FIG. 2 is a side view of the bonding wire package of the present invention. ! ......Copper wire (bonding wire), 2...
...Spool, 3...Spool case, 4.
...Oxygen adsorbent, 5...Moisture absorbent, 6...
...Bag, 7...Argon gas.

Claims (5)

[Claims] (1) In a bonding wire package in which a copper or copper alloy bonding wire for devices such as semiconductors wound around a spool is stored in a spool case, and the spool case is further sealed with a film-like bag, inside the bag: A bonding wire package characterized in that an oxygen adsorbent and/or a moisture absorbent are encapsulated in the package. (2) The bonding wire package according to claim 1, wherein the inside of the bag is evacuated. (3) The bonding wire package according to claim 1, wherein a gas inert to copper is sealed in the bag. (4) The bonding wire package according to claim 3, wherein the gas is an inert gas such as argon gas or nitrogen gas. (5) The bonding wire package according to claim 3, wherein the gas is a mixture of an inert gas such as argon gas and hydrogen gas, or a mixture of nitrogen gas and hydrogen gas.