KR20180027767A - Lead free solder composition with high ductility - Google Patents

Abstract

The present invention relates to a lead free solder composition which includes 0.02 to 6 wt% of antimony, 0.03 to 3 wt% of copper, 0.03 to 8 wt% of bismuth, 40 to 60 wt% of indium, 0.3 to 8 wt% of silver, 5 to 11 wt% of magnesium, 0.1 to 2.5 wt% of scandium, 0.4 to 1.5% wt% of niobium, and 10 to 45 wt% of tin. The lead free solder composition of the present invention has the solidification temperature which is not lower than 120°C and has excellent ductility and stability. So, it is suitable for soldering an electrical connector on a metallized surface of glass.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lead-free solder composition having high ductility,

The present invention relates to lead-free solder compositions, and more particularly to lead-free solder compositions having high ductility.

BACKGROUND OF THE INVENTION [0002] Automotive rear windows generally include electrical devices such as defrosters mounted on glass. To provide an electrical connection to an electrical device, a small portion of the metal coating is generally applied to the glass to obtain a metallized surface configured to be electrically connected to the electrical device, and the electrical connector of the electrical device Can be soldered.

In the prior art, the electrical connector is soldered onto the metallized surface of the glass with solder containing lead (Pb). However, lead-free solders have begun to be used in soldering products as lead usage is becoming increasingly limited due to environmental pollution by lead. For example, lead-free solders containing a high content of tin (Sn), typically at least 80%, are used in some industries.

However, since glass is fragile, common lead-free solders with high tin content tend to cause cracking of the glass during soldering of electrical devices on glass. Moreover, the soldering of two materials with significantly different coefficients of thermal expansion (CTE) (e.g., glass and copper) stresses the solder during cooling of the solder joint or during subsequent temperature excursions. Thus, solder compositions suitable for soldering electrical devices on glass, on the one hand, can be soldered onto a glass surface, since high melting points and corresponding high process temperatures impose high stresses on the solder during cooling, increasing the adverse effects of CTE mismatch It is necessary to have a melting point sufficiently low (i.e., a liquidus temperature) that cracks do not occur in the automobile glass during the process. As a result, the solder is further required to have good ductility. On the other hand, the melting point of the solder composition must be sufficiently high such that the solder is not melted during normal use of the vehicle, such as when the car window is closed with sunlight or under extreme environmental conditions.

A lead-free solder composition comprising 64.35 to 65.65% by weight of indium (In), 29.7 to 30.3% by weight of tin (Sn), 4.05 to 4.95% by weight of silver (Ag) and 0.25 to 0.75% by weight of copper (Hereinafter referred to as "65 indium solder").

However, indium-containing solders usually have much lower melting points than other solders. For example, 65 indium solder has a solidification temperature of 109 ° C compared to 160 ° C of lead solder and also has a liquidus temperature of 127 ° C compared to 224 ° C of lead solder. In general, the higher indium content in the solder results in a lower solidification temperature of the solder. As some automotive manufacturers require solder joints to withstand elevated temperatures, indium-containing solders have a solidification temperature of no lower than 120 without any performance degradation, and good ductility at temperatures between -40 ° C and 120 ° C .

Also, in soldering multiple closely packed electrical connectors, the soldering of the electrical connector will affect adjacent soldered electrical connectors, so that the solder must have high stability and ductility, otherwise the re- Cracks will occur.

It is an object of the present invention to provide an antimony based antimony compound which comprises 0.02 to 6 wt% of antimony, 0.03 to 3 wt% of copper, 0.03 to 8 wt% of bismuth, 40 to 60 wt% of indium, 0.3 to 8 wt% of silver, 5 to 11 wt% A lead-free solder composition comprising 0.1 to 2.5 wt%, 0.4 to 1.5 wt% niobium, and 10 to 45 wt% tin.

The present invention relates to an antimony based antimony composition comprising 0.02 to 6 wt% of antimony, 0.03 to 3 wt% of copper, 0.03 to 8 wt% of bismuth, 40 to 60 wt% of indium, 0.3 to 8 wt% of silver, 5 to 11 wt% of magnesium, 2.5 wt%, 0.4-1.5 wt% niobium, and 10-45 wt% tin.

Preferably, the lead-free solder composition may comprise 1.2 to 1.5 wt% scandium.

Preferably, the lead-free solder composition comprises 1.0 to 1.2 wt% niobium.

The lead-free solder composition may have a solidification temperature ranging from 120 < 0 > C to 135 < 0 > C.

The lead-free solder composition may also have a liquidus temperature ranging from 130 캜 to 145 캜.

Preferably, the lead-free solder composition may comprise 3 to 4% by weight of antimony.

Preferably, the lead-free solder composition may comprise from 4 to 5% by weight of bismuth.

The lead-free solder composition of the present invention is suitable for soldering electrical connectors on a metallized surface of glass, having a solidification temperature not lower than 120 占 폚, and having excellent ductility and stability.

The present disclosure will be described in detail below with some embodiments. The particular embodiments described herein are to be construed as merely illustrative of the disclosure rather than limiting the invention.

The present disclosure provides lead-free solder compositions suitable for soldering electrical devices to glass. Illustratively, the soldering is required for the manufacture of a rear window of an automobile comprising a window defrosting device consisting of an electrically resistive defrost line embedded in the rear window or deposited on the inner surface of the rear window. The defrost line is electrically connected to a pair of electrical contact strips (i.e., electrical contact surfaces, also referred to as bus bars) located on the inner surface of the rear window. The electrical contact strip may be comprised of a conductive coating deposited on the inner surface of the rear window. Typically, the electrical contact strip is formed from a silver-containing material.

In order to solve the problems of the prior art, an embodiment of the present invention is a method of manufacturing a semiconductor device comprising 0.02 to 6 wt% of antimony, 0.03 to 3 wt% of copper, 0.03 to 8 wt% of bismuth, 40 to 60 wt% of indium, Lead-free solder composition, wherein the lead-free solder composition comprises 5 to 11 wt% magnesium, 0.1 to 2.5 wt% scandium, 0.4 to 1.5 wt% niobium, and 10 to 45 wt% tin.

In this embodiment, the lead-free solder composition includes scandium and niobium, wherein the scandium has the effect of reducing particle size and raising the recrystallization temperature, improving the ductility and stability of the solder, High strength and strong corrosion resistance can be provided to improve the strength, high temperature resistance and corrosion resistance of the solder, to prevent cracking of the solder joint, and to set the solidification temperature of the solder composition within the range of 120 to 135 ° C And the liquidus temperature is increased to fall within the range of 130 캜 to 145 캜.

According to one embodiment, the lead-free solder composition may include scandium in an amount of 1.2 wt% to 1.5 wt%, and more preferably 1.1 wt%.

According to one embodiment, the lead-free solder composition may include 1.0 to 1.2% by weight of niobium, and more preferably 1.2% by weight.

According to one embodiment, the lead-free solder composition may comprise 3 wt% to 4 wt% antimony and 4 wt% to 5 wt% bismuth.

According to one embodiment, the lead-free solder composition may include magnesium in an amount of 6 to 10 wt%, preferably 7 to 9 wt%, more preferably 8 wt% . According to another embodiment, the lead-free solder composition may comprise 8 to 9 wt% magnesium.

As described above, the lead-free solder composition of the present invention has a solidification temperature ranging from 120 캜 to 135 캜 and a liquefaction temperature ranging from 130 캜 to 145 캜. The solidification temperature is defined as the temperature at which the alloy begins to substantially melt. Below the solidification temperature, the material is completely solid without a melt phase. The liquidus temperature is the maximum temperature at which crystals (unmelted metal or alloy) can coexist with the melt. Above the liquidus temperature, the material is composed solely of solutes and is homogeneous. The solder treatment temperature is higher than the liquidus temperature depending on the degree value determined by the soldering technique.

The solder composition of the present invention is lead-free and has a higher operating temperature than other solders of the same type, typically about 105 ° C. In addition, the solder composition of the present invention has much better ductility and safety than conventional conventional lead-free solder compositions.

The combination of bismuth and copper with other components improves the overall performance of the solder composition, including an expected increase in the operating temperature of the solder and improved mechanical performance of the solder under certain conditions.

In some embodiments, the lead-free solder composition may have a solidification temperature in the range of 120 < 0 > C to 135 < 0 > C.

Also in some embodiments, the lead-free solder composition may have a liquidus temperature ranging from 130 캜 to 145 캜.

In some embodiments, the lead-free solder composition may comprise 3 wt% to 4 wt% antimony.

In some embodiments, the lead-free solder composition may comprise from 4 wt% to 5 wt% of bismuth.

The lead-free solder composition of the present invention is suitable for soldering electrical connectors on a metallized surface of glass, having a solidification temperature not lower than 120 占 폚, and having excellent ductility and stability.

As shown in Table 1, the crack resistance of the solder joint formed by the lead-free solder composition of the present invention is compared with the embodiment of the present invention and some comparative examples.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 content
(weight%) Antimony One 2.3 4 4.3 5 4 5 Copper 0.1 0.5 One 1.4 2 One 2 Bismuth 0.5 1.5 3 5 7 3 5 indium 40 45 50 55 60 45 50 silver 0.5 1.5 2.5 4 6 2.5 4 magnesium 5 7 8 9 10 8 9 scandium 0.1 0.5 One 1.2 2.5 0.05 2.8 Niobium 0.4 0.6 0.8 1.1 1.5 0.05 2 Remark 10 20 25 30 40 30 40 Crack resistance √ √ √ √ √ × × ductility Great Great Great Great Great lack lack

√: No cracks in adjacent solder joints during soldering

X: Cracks in adjacent solder joints during soldering

As can be seen from the above table, when scandium is contained in the solder composition in an amount ranging from 0.1 wt% to 2.5 wt%, cracking of the solder joint formed by the lead-free solder composition of the present invention can be prevented in subsequent steps have. However, when scandium is contained in the solder composition in an amount of less than 0.1% by weight or more than 2.5% by weight, the crack resistance of the solder is lowered. In addition, when niobium is included in the solder composition in an amount ranging from 0.4% to 1.5% by weight, the solder joint formed by the lead-free solder composition of the present invention has excellent ductility. However, when niobium is contained in the solder composition in an amount of less than 0.4 wt% or more than 1.5 wt%, the ductile performance of the solder is deteriorated.

High Temperature Storage Experiment

The ductile performance of the lead-free solder according to the embodiment of the present invention was tested through a high temperature storage experiment. In this experiment, the temperature of the temperature control chamber was maintained at a constant temperature of 120 DEG C, and the electrical connector and the electrical connector were put into the temperature control chamber with the metallized surface soldered by the solder of the present invention, Hooked on electrical connector for hours. After 24 hours, the electrical connector was pulled by a digital force gauge for 3 seconds with a force of 50 N (at room temperature conditions), and no cracking of the electrical connector occurred during the experiment at all.

It is noted that the foregoing description is merely illustrative of the preferred embodiments and application technology principles of the present disclosure described above. In addition, it will be understood by those of ordinary skill in the art that the present disclosure is not limited to the specific embodiments described herein. Various changes, modifications, and substitutions may be made by one of ordinary skill in the art without departing from the scope of protection of the present disclosure. Thus, while the present disclosure has been described in detail by way of the above embodiments, it is to be understood that the present disclosure is not limited by the above embodiments, but may include other equivalent embodiments without departing from the concept of the present disclosure. The scope of the disclosure is directed to the claimed claims.

Claims (5)

Wherein the composition comprises 0.02 to 6 wt% of antimony, 0.03 to 3 wt% of copper, 0.03 to 8 wt% of bismuth, 40 to 60 wt% of indium, 0.3 to 8 wt% of silver, 5 to 11 wt% 0.4 to 1.5% by weight niobium, and 10 to 45% by weight tin. The lead-free solder composition of claim 1, comprising from 1.2 to 1.5 weight percent scandium. The lead-free solder composition according to claim 1, comprising from 1.0 to 1.2% by weight of niobium. The lead-free solder composition of claim 1, having a solidification temperature in the range of 120 to 135 占 폚. 4. The lead-free solder composition of claim 3 having a liquidus temperature in the range of from 130 to 145 < 0 > C.