JPH04149065A - High strength precision parts - Google Patents

Abstract

PURPOSE:To form precision parts having high mechanical strength and toughness, superior heat resistance, thermal stability and thermal shock resistance by adopting a compsn. consisting of yttrium oxide, aluminum oxide and zirconium oxide as a base. CONSTITUTION:Each of the title precision parts is composed of 0.5-5wt.% yttrium oxide, 10-40wt.% aluminum oxide and the balance essentially of zirconium oxide. The precision parts can be tapered and are suitably utilizable as wire bonding capillaries enabling high density wire bonding.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to bonding capillaries used for wire bonding of semiconductor manufacturing equipment such as LSI and IC, optical connector components for connecting optical fibers, and relates to high-strength precision parts used as various wire guide members,
In particular, it relates to high-strength precision parts that have excellent heat resistance, thermal stability, and thermal shock resistance, can withstand harsh operating environments, and have a long life.

(Prior Art) Materials with particularly excellent mechanical strength and heat resistance are used in precision parts that are repeatedly subjected to load and heat, such as materials for bonding capillaries in semiconductor manufacturing equipment and optical connectors. A bonding capillary of a semiconductor manufacturing device will be explained below as an example.

ICs, which are widely used as electronic components, usually consist of a lead frame, an IC chip, and a package.
The diameter of the IC chip and lead frame is 0.015mm.
Bonding is performed using a thin gold (AU) wire of approximately 0.1 mm. This wire bonding process is
This is done by feeding out the Au wire from the tip of the capillary (thin tube), alternately crimping the capillary to predetermined positions on the lead frame and IC, and fusing the wire onto the lead frame and IC chip. Since the capillary is crimped mechanically and at high speed, the capillary is strongly hit against a lead frame or the like. Also, the capillary is hit against the lead frame and momentarily becomes 100
High temperatures above 0°C may be reached. Therefore, impact resistance and heat resistance are required characteristics of the capillary.

Conventionally, the material of this capillary has been glass or ultra-hard material, but from the viewpoint of wear resistance, it has recently been made of alumina (,i,,03) polycrystalline ceramic, or made of alumina as a raw material. It has been widely used as a single crystal ruby or sapphire.

In particular, capillaries made of alumina polycrystalline ceramic are the most commonly used because they are low cost and economical. The capillary 1
As shown in FIG. 2, the outer shape of the vicinity of the tip is gradually tapered toward the tip 1a, and has a diameter of 0.025 to 0.025 to send out the Au wire 2 to the tip. It has pores 3 of about 1 mm.

(Problems to be Solved by the Invention) However, in recent years, as IC chips have become more highly integrated and smaller, there has been a demand for thinner wires and wire bonding at a higher density. Therefore, the capillary itself is required to have a small outer diameter near the tip and a small hole diameter. Conventionally, the outer diameter of the capillary tip was 2
It used to be about 0.00μm, but now it is used for highly integrated parts.
A fine capillary of about 0 μm is required.

In order to meet this demand, AI!, which was conventionally used as a capillary material! Using 203 series ceramics, the shape is the same as the conventional one, and the outer diameter of the capillary tip is 50 μm.
When manufacturing a capillary with such a capillary, the following problems arise. In other words, although it is true that a capillary with a smaller outer diameter than the conventional one can be obtained, AI! Due to the lack of strength of the capillary 203, cracks may occur in the capillary and the capillary becomes unusable within a short period of time, resulting in a short lifespan.

On the other hand, ruby and sapphire have the disadvantage that they are more expensive to manufacture than alumina polycrystalline ceramics.

In order to perform wire bonding with even higher precision, the shape of the tip of the capillary is changing from the truncated cone shape shown in FIG. 2 to the bottleneck shape shown in FIG. 1. That is, the tip of the capillary 4 shown in FIG. 1 is formed with its outer surface curved inward in order to reduce processing strain and prevent the occurrence of cracks.

Therefore, the outer diameter of the tip is much smaller than the conventional one shown in FIG. 2, and in order to maintain the same strength as the conventional one, it must be made of a material with higher toughness. Partially stabilized zirconia (Z r
Capillaries formed using 02) have also been used on a trial basis. However, partially stabilized zirconia formed into a bottleneck shape tends to chip at its tip during molding or use, and has the disadvantage of short life.

In addition, the tip of the capillary is always heated to about 3008C, and as mentioned above, it is struck against the electrode at a high speed of about 14 times per second when crimping the Au wire to the electrode lead frame, etc. Temperatures can reach temperatures as high as 1000°C or more.

However, conventional partially stabilized zirconia has relatively low heat resistance and strength, and has a problem in that a long-life capillary cannot be obtained.

The present invention has been made to solve the above problems, and has high mechanical strength and toughness, as well as excellent heat resistance, thermal stability, and thermal shock resistance, so that the tip can have a small diameter. The purpose of the present invention is to provide high-strength precision parts used in wire bonding capillaries and the like that enable high-density wire bonding.

[Structure of the invention]

(Means and Effects for Solving the Problem) In order to achieve the above object, the inventors of the present application have repeatedly investigated and researched various ceramic materials, and found that yttrium oxide (Y 20 a ) was 0.5% by weight. ~5%, aluminum oxide (1!203') from 1-0 to 40%, with high toughness and heat resistance when forming a part containing substantially zirconium oxide, and a narrow diameter shape. The present invention has been completed based on the knowledge that a precision part having excellent strength can be obtained even when formed.

Yttrium oxide, aluminum oxide, and zirconium oxide used in the high-strength precision parts that are the object of the present invention can be those that are generally commercially available as powders. Moreover, yttrium oxide is 0. It is contained in an amount of 5 to 5% by weight. This yttrium oxide functions as a stabilizer that partially stabilizes zirconium oxide, and has the effect of increasing the toughness and strength of precision parts. However, if the content of yttrium oxide is less than 0.5%, the toughness and strength will be insufficient, while if the content exceeds 5%, it will be difficult to sinter, so the content should be in the range of 0.5 to 5%. is set within.

It also contains 10 to 40% by weight of aluminum oxide.

This aluminum oxide is added to improve heat resistance and thermal stability. However, if the content of aluminum oxide is less than 10%, the heat resistance stability will be insufficient, while if the content exceeds 40%, the sinterability will decrease like yttrium oxide, so the content should be 10 to 40%. Set within the range.

Next, the manufacturing process of a precision component having the characteristics targeted by the present invention will be explained using the bonding capillary as an example.

That is, first, raw material powders of yttrium oxide, aluminum oxide, and zirconium oxide are weighed so as to have the above composition and mixed in a ball mill or the like.

It is preferable to use raw material powders having an average particle size of 20 to 200 particles because the ceramics obtained after combustion will be dense and have high hardness.

The obtained mixed powder is press-molded at room temperature and processed into a green molded body. What is important in processing this green molded body is that it is rough-machined to form straight pores 5 and cheek holes 6 as shown in Figure 1, so the capillary body is ground during this drilling process. It must be strong enough to be played on a board, etc. Normally, in order to ensure this strength, the bulk density of the molded body may be set to 25 to 3.8 g/ctd. For this purpose, it is preferable to set the press pressure during pressure molding to a range of 700 to 1000 kg/d.

After completing the perforation process, this molded body is sintered under predetermined conditions. The properties of the obtained sintered body, such as mechanical strength and hardness, are greatly influenced by the sintering conditions at this time. In order to exhibit the above-mentioned characteristic range, the sintering temperature may be 1400 to 1600° C. and the sintering time may be 0.5 to 4 hours, for example.

Furthermore, the capillary formed by sintering does not have a shape in which the outer diameter gradually decreases toward the tip like the conventional capillary 1 shown in FIG. 2, but the capillary 4 shown in FIG. It has a so-called bottleneck shape, in which the outer diameter of the tube suddenly decreases from a predetermined position. Therefore, there is less processing strain at the tip, making it possible to crimp the Au wire with high precision.

In addition, the addition of yttrium oxide forms a ceramic material with high toughness, so even if the tip is formed into a fine bottleneck shape, cracks are unlikely to occur in the capillary and stable bonding can be achieved over a long period of time. performance can be maintained.

Furthermore, aluminum oxide is added to form a ceramic material with significantly improved heat resistance, which reduces chipping and abrasion of the capillary tip due to heat shock, making it possible to maintain stable honding function over a long period of time. This makes it possible to stabilize the quality of semiconductor products such as ICs and reduce variations in quality.

In addition, since this capillary 4 is made of high-strength ceramics, in order to obtain the same strength, the tip 4a is relatively
It is possible to further reduce the pore diameter and outer diameter of the pore size, and it is possible to sufficiently respond to higher density and smaller size of the final product.

The high-toughness precision component according to the present invention is applied to component materials that require heat resistance and high toughness, such as optical connector members and various wire guides, in addition to wire bonding capillaries as described above. However, its scope of application is not limited to the above-mentioned parts, but can be applied to all precision parts that have complex shapes, are thin, and are prone to chipping or cracking.

(Example) Next, examples of the present invention will be described in more detail.

Examples 1 to 6 The capillary has a shape as shown in Fig. 1, and the outer diameter of the capillary tip is 70 μm1 The hole diameter of the capillary tip is 25 μm1 The outer diameter of the capillary body before the outer diameter suddenly decreases is 300 μm
1. The position from the tip of the bottle neck is 400 μm, 1. The opening degree θ of the taper hole 6 is 18 degrees, and the capillary has a total length of 11 cm. The yttrium oxide content is 0.7 as shown in the ceramic composition shown in the left column of Table 1. -4.0%, the content of aluminum oxide was varied in the range of 12 to 38%, and the remainder was formed of a sintered body consisting of zirconium oxide (Zr02) to form Examples 1 to 6.

In order to evaluate the mechanical strength of the obtained capillary, bending strength and fracture toughness were measured. In addition, in order to investigate the heat resistance, strength, and lifespan of the capillary itself, we actually inserted a wire into the capillary and performed wire bonding.
The possible number of hondings was measured. The above results are shown in Table 1.

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.

Comparative Examples 1 to 4 On the other hand, as Comparative Examples 1 and 2, powder mixtures were prepared in which the yttrium oxide content was 0.3% and 7%, respectively, the aluminum oxide content was 20%, and the balance was zirconium oxide. A capillary sintered body was formed in the same shape and under the same conditions as in Examples 1 to 6, and the mechanical properties and the number of hondings were measured in the same manner.

In addition, as Comparative Examples 3 and 4, powder mixtures containing 4% yttrium oxide, 6% and 50% aluminum oxide, and the remainder zirconium oxide were treated under the same conditions as Examples 1 to 6. Then, a capillary sintered body was formed and the characteristic values were measured in the same manner.

Comparative Example 5 Also, as Comparative Example 5, yttrium oxide (Y2O2) 3
Capillaries having the same shape and size as those in Examples 1 to 6 were manufactured using sintered bodies in which the balance by weight was zirconium oxide (ZrO3), and the mechanical properties and the number of wire bondings were measured in the same manner.

Comparative Example 6 Furthermore, as Comparative Example 6, magnesium oxide (Mgo) 0.
2% by weight, silicon oxide (S 102 ) 0°2% by weight,
Al2 with the remainder consisting of aluminum oxide (A1203)
Capillaries having the same shape and size as those in Examples 1 to 6 were manufactured using O3 ceramics, and their characteristic values were measured in the same manner.

The measurement results of Examples 12 to 6 and Comparative Examples 1 to 6 are shown in Table 1 below.

[Margin below]

As is clear from the results in Table 1, within the range of the IJ'7 oxide (Y203) content and the aluminum oxide (A1203) content shown in Examples 1 to 6, the Mg and Compared to conventional capillaries made of aluminum oxide-based ceramics doped with S+02, higher fracture toughness values are obtained in all cases, and the number of bonding operations is also dramatically increased.

On the other hand, as shown in Comparative Examples 1 and 2, those with too little yttrium oxide have comparatively low bending strength and fracture toughness values, and the number of bondings is also low. Connection failures occurred frequently.

Furthermore, as shown in Comparative Examples 3 and 4, those with too little aluminum oxide content have low heat resistance, are prone to cracking and breakage due to heat shock, and have a low bonding frequency.
If there is too much, the sinterability will be low and the life will be short.

Furthermore, as shown in Comparative Example 5, even if a material contains an appropriate amount of yttrium oxide, a material that does not contain aluminum oxide still has low heat resistance and is prone to cracking due to heat shock, and the number of hondings is also reduced.

〔Effect of the invention〕

As explained above, according to the high-strength precision parts according to the present invention, the fracture toughness value and heat resistance are significantly improved compared to conventional products, so even when processed into fine shapes, there is no possibility of chipping due to heat shock during use. High-precision processing is possible without cracking.

In particular, when this high-strength precision component is used as a wire bonding capillary, there is little adhesion of Au conductor or lead frame powder to the tip (also, it has high high-temperature strength and thermal shock resistance, so it is less likely to chip or wear due to heat shock). Not only can wire bonding be performed stably and the quality of semiconductor components such as ICs can be stabilized, but the cost can be lower than that of ruby sapphire. Capillaries with many features can be provided.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a capillary as a high-strength precision component according to the present invention, and FIG. 2 is a partial sectional view showing an example of the structure of a conventional capillary. 1... Capillary, 1a... Tip, 2... Au wire, 3... Pore, 4... Capillary, 4a... Tip, 5... Pore, 6... Taper Hole, θ...Opening degree of the tapered hole. Applicant's agent Hisashi Hatano 1 Museum 211

Claims (1)

[Claims] Yttrium oxide in weight percentage of 0.5% or more5
% or less, and contains 10% or more and 40% or less of aluminum oxide, and the remainder substantially consists of zirconium oxide.