JPH10180480A - Lead-free soldering material and electronic parts using the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable electronic parts by incorporating at least one kind of Fe and Ni of the prescribed quantity into Sn as the lead-free soldering material and performing the soldering through a Ni film thereby improving joining performance. SOLUTION: The lead-free soldering material has the composition consisting of, by weight, at least one kind of 0.01-5.0% Fe and Ni, and the balance Sn with inevitable impurities, preferably, 0.01-4.99% Fe, 0.01-4.99% Ni while the sum of Fe and Ni is 0.02-5.0%, and the balance Sn with inevitable impurities. An electronic member is joined with a substrate to form an electronic parts through the Ni film using the lead-free soldering material of this composition. In the soldering material, Sn raw material is preferably >=99.9wt.%, and the higher its purity is, the more the mixing of Pb can be avoided. The joining property with Ni interposition can be improved even in the Sn-based lead-free soldering material by the multiplier effect of at least one kind of Fe and Ni with Sn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-free solder material which does not use lead and has excellent performance for preventing damage to a Ni film. More specifically, the present invention relates to a method for connecting an IC chip, a capacitor, and a substrate with a Ni film. The present invention relates to a lead-free solder material suitable for use in joining and an electronic component using the solder material.

[0002]

2. Description of the Related Art At present, when a semiconductor device, a hybrid IC or the like is mounted on an IC chip or a capacitor and the substrate is joined, a lead (Pb) -based solder represented by a composition of 5% by weight Sn-95% by weight Pb is used. Joining is performed using materials. On the other hand, recently, there has been an increasing demand for a lead-free solder material that does not use lead due to issues such as disposal of electronic devices and the like and promotion of environmental measures. For this reason, a lead-free solder material suitable for joining a substrate to a soldering material such as the IC chip or capacitor is required, but an Sn-based lead-free solder material is most suitable in consideration of melting point, wettability, and cost.

In the present invention, the term "electronic member" refers to a soldering material which is joined to a substrate when mounting an electronic component, such as an electronic element such as an IC chip, a chip component such as a capacitor or a resistor. Can be The electronic component refers to a semiconductor device mounted by soldering, a functional component such as a capacitor, and a wiring board on which the functional component and the like are mounted.

[0004] Various proposals have recently been made as a lead-free solder material suitable for bonding the electronic member and the substrate from the above-mentioned circumstances. For example, Japanese Patent Application Laid-Open No. 8-132277 proposes a Sn-based lead-free solder material suitable for mounting small chip components and the like on a circuit board of an electronic device or the like with high accuracy.

On the other hand, when a Pb-based solder material is used for soldering an electronic member and a board, soldering is usually performed with a coating of Ni, Cu or the like interposed therebetween in order to improve the bonding property. I have. However, when soldering is performed using the Sn-based lead-free solder material with a Ni coating interposed therebetween, there is a problem that the improvement of the joining property as obtained when the Pb-based solder material is used cannot be obtained. Was.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, in the present invention, the composition is lead-free, Sn-based,
Sn that can improve the bondability (hereinafter referred to as Ni-bonded bondability) by soldering with an i-film interposed
It is an object to provide a lead-free solder material and an electronic component using the same.

[0007]

As a result of intensive studies by the present inventors, the above-mentioned object can be attained by making the composition of the solder material include at least one of Fe and Ni in Sn in a predetermined amount. It has been found that the present invention can be achieved, and the present invention has been completed.

That is, the lead-free solder material of the present invention is characterized in claim 1
As described, at least one of Fe and Ni is 0.01 to 5.0% by weight, and the balance is composed of Sn and unavoidable impurities.

The lead-free solder material according to the present invention is characterized in that Fe: 0.01 to 4.99% by weight and Ni:
0.01 to 4.99% by weight and the total amount is 0.02 to
It is characterized by 5.0% by weight and the balance consisting of Sn and unavoidable impurities.

In the electronic component according to the present invention, at least one of Fe and Ni is contained in an amount of 0.01 to 0.01.
The electronic member and the substrate are joined via a Ni film using a lead-free solder material containing 5.0% by weight and the balance of Sn and unavoidable impurities.

The electronic component according to the present invention is characterized in that Fe: 0.01 to 4.99% by weight and Ni: 0.0
An electronic member and a substrate are joined via a Ni coating by using a lead-free solder material comprising 1 to 4.99% by weight, the total amount being 0.02 to 5.0% by weight, and the balance being Sn and unavoidable impurities. It is characterized by having done.

In the electronic component of the present invention, at least one of Fe and Ni is contained in an amount of 0.01 to 0.01.
4.99% by weight, 0.01% of selected components other than Fe and Ni
The electronic member and the substrate are joined via a Ni coating using a lead-free solder material of up to 4.99% by weight, the total amount of which is 0.02 to 5.0% by weight, and the balance being Sn and unavoidable impurities. It is characterized by having done.

Further, the electronic component of the present invention is characterized in that Fe: 0.01 to 4.98% by weight and Ni: 0.0
1-4.98% by weight, optional components other than Fe and Ni: 0.
01 to 4.98% by weight, and the total amount is from 0.03 to 5.
The electronic member and the substrate are joined via a Ni coating by using a lead-free solder material containing 0% by weight and the balance consisting of Sn and unavoidable impurities.

The electronic component of the present invention is characterized in that the electronic member is an IC chip or a capacitor.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The composition of the solder material according to the present invention needs to be lead-free. The lead-free in the present invention means that the Pb content is reduced to a preferable amount for environmental measures,
Preferably, it is a lead-free one reduced to a trace amount contained in the inevitable impurities.

The solder material of the present invention is Sn-based in consideration of melting point, wettability, cost and the like. As the Sn raw material in the present invention, it is preferable to use high purity Sn of 99.9% by weight or more. More preferably, it is 99.99% by weight or more. The higher the purity of the Sn raw material, the more Pb in the unavoidable impurities
It is preferable because it is possible to avoid the contamination.

In the present invention, at least one of Fe and Ni and the remainder are made of a lead-free solder material comprising Sn and unavoidable impurities, so that at least one of Fe and Ni and Sn are mixed. Due to the synergistic effect, the composition becomes S
Although it is an n-based lead-free solder material, it is possible to improve the Ni intervening bonding property.

In a Sn-based lead-free solder material containing at least one of Fe and Ni, when the content of at least one of Fe and Ni is 0.01% by weight or more, 0.0
Compared with less than 1% by weight, the Ni intervening bondability can be greatly improved. Therefore, the content of at least one of Fe and Ni needs to be 0.01% by weight or more. Among these, when the content of at least one of Fe and Ni is 0.1% by weight or more, the Ni intervening bondability is further improved, and therefore it is preferably 0.1% by weight or more.

When the content of at least one of Fe and Ni exceeds 5% by weight, the Ni intervening bondability is reduced as compared with 5% by weight or less. Therefore, the content of at least one of Fe and Ni needs to be 5% by weight or less.

In at least one of the predetermined amounts of Fe and Ni, the content of Fe is 0.01 to 4.99% by weight and the content of Ni is 0.01 to 4.99% by weight. .
By setting the content to 02 to 5% by weight, the Ni intervening bondability is further improved, and it is more preferably used. Most preferably, the total amount is 0.1 to 5% by weight.

For this reason, at least one of Fe and Ni
The content of at least one of Fe and Ni in the lead-free solder material whose seeds and balance are Sn and unavoidable impurities is determined to be 0.01 to 5% by weight. Preferably it is 0.1 to 5% by weight. More preferably, 0.01 to 4.9 Fe is used.
9% by weight and 0.01 to 4.99% by weight of Ni, with the total amount being 0.02 to 5% by weight, and most preferably the total amount is 0.1 to 5% by weight. It is.

In the lead-free solder material of the present invention, at least one of Fe and Ni is contained in Sn at 0.01 to 4%.
/ 99% by weight as long as the content of selected components other than Fe and Ni is 0.01 to 4.99% by weight, and the total amount is 0.1%.
When the content is from 02 to 5% by weight, the Ni interposition bonding property can be improved. In addition, 0.01 to 4.0 of Fe is contained in Sn.
As long as 98% by weight and 0.01 to 4.98% by weight of Ni are contained, optional components other than Fe and Ni are contained at 0.01 to 4.98%.
% By weight, and when the total amount is 0.03 to 5.0% by weight, it is possible to improve the Ni-mediated bonding property.

In the present invention, the selected component is an additive having a function of not losing the effect (improvement of Ni intervening bonding) obtained by including at least one of a predetermined amount of Fe and Ni in Sn. These are so-called incidental elements which can be optionally contained.
The optional components according to the present invention include Zn, Si, Cu,
P, Ag, Sb and the like can be exemplified. However, it is preferable not to contain a selective component other than Fe and Ni in order to improve the Ni interposed bonding property.

In the lead-free solder material of the present invention, the total content of Sn and unavoidable impurities must be 95% by weight or more. At this time, it is possible to improve the Ni interposed bonding property.

In the lead-free solder material of the present invention, it is apparent that the inclusion of at least one of a predetermined amount of Fe and Ni in a predetermined amount of Sn can improve the Ni-mediated bonding. This is probably because the degree of damage to the Ni film is small. Observation of the degree of damage of the Ni film by solder reflow after the solder bonding on the Ni film shows that the damage of the Ni film is large in the case of the conventional Sn-based lead-free solder material. In the case of the base lead-free solder material, it can be said that the damage of the Ni film is minute.

The Sn-based lead-free solder material used in the present invention can be used after being processed into a tape, wire, pellet, or ball shape, or can be used as an immersion bath or vapor deposition material. It can also be used as a composite material mixed with high melting point particles.

The following methods can be exemplified as a method for processing a tape or a wire. In the case of a tape, it is cast into an ingot and then subjected to rolling and slitting to finish the tape into a predetermined size. The tape has a thickness of 0.05 to 0.5 mm and a width of 0.5 to 5.
A range of 0 mm is preferred. In the case of a wire, a wire is obtained by extruding an ingot or a quenching method in which a molten metal is jetted into water, and finished to a wire of a predetermined size by wire drawing. The wire size is preferably in the range of 0.05 to 5.0 mm in diameter.

When using the Sn-based lead-free solder material according to the present invention for die bonding or hybrid IC for joining a semiconductor element to a substrate, high melting point particles are mixed into the solder material in order to maintain the levelness of the semiconductor element and the substrate. It can be used as a composite material. The melting point of the high melting point particles is preferably 400 ° C. or more, the content is 0.001 to 0.6% by weight, and the diameter of the particles is preferably 5 to 100 μm. As the material of the high melting point particles, metal particles such as Cu and Ni, SiO ₂
And carbides such as SiC.

The product of the present invention can be used on a surface of an electronic member or a substrate.
In the case where the i-coat is applied, the joining property by soldering can be improved. Among them, it is preferable to apply a Ni coating to ceramics such as alumina or the like and solder them. As a method for forming the Ni film, a method such as plating or vapor deposition is used. The thickness of the Ni coating by evaporation is 1
000-3000 Å is preferred.

Next, an example of an electronic component according to the present invention will be described with reference to FIG. FIG. 1 is a side view of the semiconductor device before resin sealing. Die 1 of lead frame as substrate
Ni plating 2 is provided on the surface. I which is a semiconductor element
An Al electrode 6 is provided on the upper surface of the C chip 5, and a Ni plating 4 as a metallized layer is provided on the lower surface. That is, the solder layer 3
Is connected to the dies 1 through the plating layers 2 and 4 which are Ni coatings.
C chip 5 is connected. Al on the upper surface of the IC chip 5
A gold wire 7 is wire-bonded to the electrode 6. The connection method using the solder layer 3 is as follows.
, A solder pellet and an IC chip 5 having a Ni plating layer 4 are sequentially stacked on the surface of the die 1 and passed through a heating furnace in a hydrogen atmosphere to perform soldering. Also, an electronic member such as an IC chip or a capacitor having a Ni coating is connected and mounted via solder at a predetermined position on the wiring on the printed board,
Thereafter, resin sealing is performed to obtain a semiconductor device which is an electronic component.

[0032]

【Example】

(Embodiment 1) A description will be given with reference to a schematic diagram of a test apparatus and a measurement method shown in FIG. Purity 99.99 wt% Sn
A predetermined amount of the base metal and Fe were mixed, melted in vacuum, and then cast to obtain an ingot having the composition shown in Table 1. The ingot was rolled to obtain a tape having a thickness of 0.1 mm and a width of 10.0 mm.
Further, the tape was used as a raw material to perform press working, thereby completing a solder pellet having a thickness of 0.1 mm and a diameter of 1.8 mm. 2000 angstrom Ni coatings 12 and 12 ′ were formed on the alumina substrates 11 and 11 ′ by vapor deposition, and a flux (R5003 made by Nippon Alpha Metal) was applied via the Ni coatings 12 and 12 ′ as shown in the figure. The solder pellet 13 is placed at three places, and the Ni coating 1
2, 12 'were wired by leads 14 as shown. Next, after heating the test apparatus in a heating furnace in a hydrogen atmosphere,
The alumina substrate 1 is taken out of the furnace and cooled.
1, 11 'were soldered and joined at three places via Ni coatings 12, 12'. Next, as shown in the figure, a constant current of 1 mA was passed to measure the voltages V ₁ and V ₂ between the solder pellets, and the resistance was measured from R = (V ₁ + V ₂ ) / I. The same test apparatus as that shown in FIG.
Deterioration performance due to soldering repeated 0 times was tested. The resistance value R when performing once soldering aforementioned soldering method as R _1, the resistance value R when performing 10 times
Was a R _10, and the soldering property deterioration degree of the (R ₁₀ / R _1). Table 2 shows the average values of the five test devices as the measurement results of the degree of deterioration in solderability.

(Examples 2 to 20 / Comparative Examples 1 to 6) Solder pellets were obtained in the same manner as in Example 1 except that the composition of the ingot described in Example 1 was as described in Table 1. After that, a test device was prepared and a solderability deterioration test was performed. Table 2 shows the average value of the five test devices as the measurement result of the degree of deterioration in solderability.

[0034]

[Table 1]

[0035]

[Table 2]

According to the above measurement results, when a Ni coating was formed on the surface of alumina having poor solderability, and a soldering test was performed. When the Sn-based lead-free solder material according to the present invention was used, the Pb-based solder material was used. As a result, an improvement in the bondability obtained when using was obtained. When the conventional Sn-based lead-free solder material is used, a sufficient improvement in the joining property has not been obtained, but it has been found that the reason is that the Ni coating is dissolved and damaged and a non-joining surface is formed. Focusing on the fact that the formation of the non-bonded surface increases the electrical resistance, in this test, the above-mentioned (R ₁₀ / R ₁ ) was used as the solderability evaluation criterion as the solderability deterioration degree.

That is, 0.01 to 5.0% by weight of Fe
And Examples 1 to 4 in which the balance is unavoidable impurities and Sn,
The degree of deterioration in solderability was 1.6 to 2.0, indicating an excellent effect. Among them, the content of Fe is 0.1 to 5.0% by weight.
No. 1 exhibited a more excellent effect with a solderability deterioration degree of 1.6 to 1.8.

In Examples 5 to 8 in which 0.01 to 5.0% by weight of Ni and the balance were unavoidable impurities and Sn, the degree of deterioration in solderability was 1.6 to 2.0, showing excellent effects. . Among them, those having a Ni content of 0.1 to 5.0% by weight are:
Deterioration degree of solderability was 1.6 to 1.8, which was a further excellent effect.

0.01 to 4.0% by weight of Fe and 0.01
To 4.0% by weight of Ni in a total amount of 0.2 to 5.0.
Example 9 in which the weight percent is used and the balance is unavoidable impurities and Sn.
No. 16 to No. 16 showed a further excellent effect with a solderability deterioration degree of 1.1 to 1.4.

At least one of the predetermined amounts of Fe and Ni
Seed and Zn, Si, Cu, P as selective components 0.2 to 0.2
The deterioration of the solderability of Examples 17 to 20 in which 3.0% by weight and the balance are unavoidable impurities and Sn was 2.3 to 2.7.
A tentative result has been obtained.

On the other hand, in Comparative Example 1 consisting only of unavoidable impurities and Sn, the degree of deterioration in solderability was 3.9, which was poor. Comparative Example 2, which does not contain both predetermined amounts of Fe and Ni, contains 0.2% by weight of Si as a selective component, and the balance is unavoidable impurities and Sn, has a poor degree of deterioration in solderability of 3.8. Met. In Comparative Examples 3 and 4, in which 7.0% by weight of Fe or Ni and the balance were unavoidable impurities and Sn, the degree of deterioration in solderability was as poor as 3.5 to 3.6. Fe
And Ni as a total amount of 7.0% by weight, and the balance of Comparative Example 5 in which the balance was unavoidable impurities and Sn was as poor as 3.2. Predetermined amounts of Fe and Ni
Of at least one selected from the group consisting of 8.0% by weight Zn as a selective component, and the balance being unavoidable impurities and S
The degree of solderability deterioration of Comparative Example 6 where n was 3.1 was as poor as 3.1.

[0042]

As described above, according to the lead-free solder material of the present invention, at least one of a predetermined amount of Fe and Ni is contained in Sn at the time of soldering with a Ni film interposed therebetween. The degree of property deterioration was improved. Therefore, it is a lead-free Sn base, and has an excellent effect that the joining property when soldering with a Ni coating interposed can be improved. As long as it contains at least one of the predetermined amounts of Fe and Ni, which are essential components of the present invention, it may contain up to 0.48% by weight of selected components. However, among them, a certain amount of Fe and N
By including at least one of i in Sn, N
A more favorable effect was obtained that could improve the bonding property when soldering with the i-coat interposed. Further, a predetermined amount of F
By including both e and Ni in Sn, Ni
The most favorable effect was obtained that could improve the bonding property when soldering with a coating interposed.

According to the electronic component of the present invention, since the electronic member and the substrate are soldered by using the above-mentioned lead-free solder material with a Ni coating interposed therebetween, it is possible to cope with problems such as disposal and environmental measures. It was possible to provide a highly reliable electronic component which was excellent in bonding property between the electronic member and the substrate. Among these, when a lead-free solder material containing a predetermined amount of at least one of Fe and Ni without containing a selective component is used, soldering jointability can be improved, and a more reliable electronic component can be obtained. . In addition, when a lead-free solder material containing both predetermined amounts of Fe and Ni was used, solderability could be further improved, and the most reliable electronic component was obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a semiconductor device illustrating an example of an electronic component.

FIG. 2 is a schematic diagram illustrating a test apparatus and a measurement method.

[Explanation of symbols]

 1: Die of lead frame 2, 4: Ni plating (Ni coating) 3: Solder layer (lead-free solder material) 5: IC chip 6: Al electrode 7: Wire 11, 11 ': Alumina substrate 12, 12': Ni coating 13: Solder pellet (lead-free solder material) 14: Lead 15: Power supply 16: Voltmeter 17: Ammeter

Claims (7)

[Claims] 1. A lead-free solder material comprising 0.01 to 5.0% by weight of at least one of iron (Fe) and nickel (Ni), with the balance being tin (Sn) and unavoidable impurities. 2. Iron (Fe) is 0.01 to 4.99% by weight, nickel (Ni) is 0.01 to 4.99% by weight, and the total amount is 0.02 to 5.0%. %, And the balance is tin (Sn) and a lead-free solder material composed of unavoidable impurities. 3. An electronic device using a lead-free solder material comprising at least one of iron (Fe) and nickel (Ni) in an amount of 0.01 to 5.0% by weight and a balance of tin (Sn) and unavoidable impurities. An electronic component in which a member and a substrate are joined via a Ni film. 4. An iron (Fe) content of 0.01 to 4.99% by weight and a nickel (Ni) content of 0.01 to 4.99% by weight, the total amount of which is 0.02 to 5.0%. An electronic component in which an electronic member and a substrate are joined via a Ni coating by using a lead-free solder material containing tin (Sn) and unavoidable impurities in the balance. 5. At least one of iron (Fe) and nickel (Ni) is 0.01 to 4.99% by weight, the optional component is 0.01 to 4.99% by weight, and the total amount is An electronic component in which an electronic member and a substrate are joined via a Ni coating using a lead-free solder material containing 0.02 to 5.0% by weight and the balance being tin (Sn) and unavoidable impurities. 6. An iron (Fe) content of 0.01 to 4.98% by weight, a nickel (Ni) content of 0.01 to 4.98% by weight, and a selective component of 0.01 to 4.98% by weight. An electronic component in which an electronic member and a substrate are joined via a Ni coating using a lead-free solder material having a total amount of 0.03 to 5.0% by weight and a balance of tin (Sn) and unavoidable impurities. 7. The electronic component according to claim 3, wherein the electronic member is an IC chip or a capacitor.