JPS6276527A - Wire bonding capillary - Google Patents

Abstract

PURPOSE:To realize high-density wire bonding with a capillary having a tip of a fine diameter by making the capillary have a bottle neck-shaped part and formed of ceramics comprising one kind of groups Si3N4, ZrO2, Al2O3, SiC, and Si-Al-O-N, as a main element. CONSTITUTION:A capillary 2 is formed of ceramics which comprise one kind selected from groups Si3N4, ZrO2, Al2O3, SiC, and Si-Al-O-N, as a main element. Si3N4 group ceramics comprising Al2O3 in 0.5-5wt%, AlN in 0.5-5wt%, Y2O3 in 1-7wt%, and Si3N4 in the remnant are desirable. And, the capillary 2 has a bottle neck shaped in which its outer diameter becomes small rapidly from a prescribed portion. Therefore, a capillary having a high degree of strength, even with its inner and outer diameters of the tip 2a made small, can be obtained. Besides, because the capillary is made of very strong ceramics, the inner and outer diameters of the tip 2 can be made smaller.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a wire bonding capillary, and more particularly, the present invention relates to a wire bonding capillary that has high mechanical strength, can therefore be formed into a small diameter tip, and has a high density wire bonding capillary. This invention relates to a wire bonding capillary that makes possible the following.

[Technical background of the invention and its problems] ICs, which are widely used as electronic components, usually consist of a lead frame, an IC chip, and a package, and the IC chip and lead frame are wire bonded using Au wire. ing. This wire bonding is performed by putting Au wires into capillaries (thin tubes), placing the capillaries alternately at predetermined positions on the lead frame and the IC, and fusing the wires onto the lead frame and the IC chip. Since this capillary arrangement is performed mechanically and at high speed, the capillary is strongly hit against a lead frame or the like. therefore.

The capillary itself is required to have #impact resistance.

Conventionally, this capillary is made of a material such as 1203 series ceramics, and the outer shape of its tip is as follows:
As shown in FIG. 2, is the shape gradually tapering toward the tip 1a? I was doing it.

Incidentally, in recent years, with the miniaturization of IC chips, there has been a demand for thinner wires and high-density wire bonding. Therefore, the capillary itself needs to have a small outer diameter and a small hole diameter near the tip. Conventionally, the outer diameter of the tip of a capillary was about 200 μm, but capillaries with a diameter of about 50 μm are now required.

In order to meet this demand, Af120. When manufacturing a capillary using ceramics having the same shape as the conventional one and having an outer diameter of 50 mm at the capillary tip, the following problems occur. In other words, although it is true that a capillary with a smaller outer diameter than the conventional method can be obtained, the problem is that the capillary becomes unusable due to the insufficient strength of Al2O5, which causes cranks to occur in the capillary.

[Objective of the Invention] The present invention solves the above-mentioned problems and provides a wire bonding capillary that has high mechanical strength, can have a small diameter tip, and enables high-density wire bonding. purpose.

[Summary of the Invention] As a result of extensive research in order to achieve the above object, the present inventors have discovered that the shape of the capillary near its tip has a bottleneck shape as described below. The present invention was completed based on the discovery that if the material is a high-strength ceramic as described later, a capillary with excellent strength can be obtained even if the pore diameter and outer diameter are made small.

That is, the wire bonding capillary of the present invention is
It is characterized by having a bottleneck-shaped portion. Also, the capillary is Si3N4, ZrO2゜A203
, SiC, Si-A-N-O-N as a main component.

First, in the capillary of the present invention, as shown in FIG. 1, the vicinity of the tip of the capillary 2 has a bottleneck shape. That is, the capillary of the present invention does not have a shape in which the outer diameter of the capillary gradually tapers toward the tip like the conventional capillary 1 shown in FIG. It has a so-called Bo1-, +Renneck shape. By having such a bottleneck shape, the tip 2
Even if the hole diameter and outer diameter of a are made smaller, a high-strength cavity 1) can be obtained. Furthermore, since this capillary is made of high-strength ceramics, which will be described later, the hole diameter and outer diameter of the tip 2a can be further reduced.

In the bottle A, a capillary having a hollow-shaped part, the position where the outer diameter suddenly decreases is determined by determining the outer diameter of the tip by adjusting the hole diameter of the tip 2a from 10 to 40μ, although it cannot be determined generally. When the thickness is 40 to 150 μm, it is preferably 02 to 0.5 mm from the capillary tip 2a. In addition, at the position where the outer diameter suddenly decreases, the rate of decrease in the outer diameter is determined by the outer diameter before the decrease.
When the number of units is 300 to 350, the outer diameter after reduction is preferably 200 to 250 tnm. Further, it is preferable that the angle (θ in FIG. 1) of the portion of the capillary where the wire is arranged into the hole at the tip is set to about 15 to 20'C. Note that the shape of the bottleneck in the capillary of the present invention is not limited to the above numerical values or the shape shown in FIG. 1, but the shape of the bottleneck can be as shown in FIG. It is preferable to have a shape that is curved inward, otherwise machining distortion remains and is likely to cause cracks.

Next, the capillary of the present invention is made of Si3Na, ZrO
2゜Al203, SiC, Si-AfL-0-N
It is made of ceramics whose main component is one selected from the group of. Among these ceramics, Aai2
03° is 0.5-5% by weight, and A-N is 0.5-5% by weight.

Preferred examples include Si3N4 ceramics containing 1 to 7% by weight of Y2O3 and the remainder being Si3N4. In addition, as stabilizers, 0.5 to 3% by weight of CaO, 1 to 7% by weight of Y2O3, and 0.0% of I'1gO are used.
5-3% by weight, AI, 0. Partially stabilized zirconia containing 0.1 to 0.5% by weight with the remainder being ZrO2 is also preferred.

These ceramics have excellent mechanical strength, at least better than Al2O type ceramics, and have a bending strength of 60 to 100 kg/mmZ.

The capillary of the present invention can be manufactured by adding, for example, the above-described main component powder (e.g., Si3 N4, ZrO2, etc.) to
This is done by blending various sintering aids into a molded body of a predetermined shape, cutting the molded body to form a capillary precursor, and sintering it under predetermined conditions.

[Embodiments of the invention] Example 1 Outer diameter of the capillary tip is 70μ, hole diameter of the capillary tip is 2
5 houses, outer diameter 300μm before the outer diameter suddenly decreases, position 400yn from the tip of the bottleneck, 0618°C
A capillary having a total length of 111 Ilffl was manufactured from the following ceramics.

A capillary of the above size was manufactured from a Si3N4 sintered body consisting of A-cross, 033% double discharge, Y2o 35% by weight, A-cross N3% by weight, and the balance being Si3N4.

In order to examine the mechanical strength of the obtained capillary, bending strength and fracture toughness were measured. In addition, in order to examine the strength and life of the capillary itself, a wire was actually inserted into the capillary and wire bonding was performed, and the possible number of bondings was measured and the results of 0 or more are shown in the table. Further, when the bonding properties of an IC chip and a lead frame bonded by wire bonding using the capillary of the present invention were examined, it was found that both were bonded well.

Example 2 Gao single star% is used as the capillary material.

Example 1 except that partially stabilized zirconia consisting of 35% by weight of Y2O, 1% by weight of Mg, and the balance ZrO2 was used.
A capillary with the same shape and size was manufactured and measurements were performed in the same manner.

Comparative example As the capillary material, Mg0 is 0.2% by weight.

120 consisting of SiO20.2% by weight, balance Al203
A capillary was manufactured using 3-series ceramic 7x, with a tip having a shape as shown in FIG. 2, an outer diameter of 70mm at the tip, and a hole diameter of 25IIj at the tip of the capillary.

Then, when measurements were carried out in the same manner as in Example 1, the capillary broke during the wire bonding test. The above results are shown in the table.

[Effects of the Invention] As is clear from the examples, the wire bonding capillary of the present invention has an outer diameter of 50 mm at the tip of the capillary.
Even when the capillary is as small as μ, it does not break and has excellent mechanical strength and a long life, and its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a capillary of the present invention, and FIG. 2 is a partial sectional view showing a conventional capillary. 2: Capillary of the present invention 1: Conventional capillary Fig. 1 Fig. 2

Claims (1)

[Claims] 1. A wire bonding capillary characterized by having a bottleneck-shaped portion. 2. Wire bonding capillary is Si_3N_4Z
rO_2, Al_2O_3, SiC, Si-Al-O-
2. The wire bonding capillary according to claim 1, wherein the wire bonding capillary is made of a ceramic whose main component is at least one member selected from the group consisting of N. 3. Wire bonding capillary is Si_3N_4,
The wire bonding capillary according to claim 1, wherein the wire bonding capillary is made of a ceramic whose main component is at least one member selected from the group of ZrO_2, SiC, and Si-Al-O-N.