Patent Application
20240100634
This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0123648, filed on Sep. 28, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
Embodiments relate to a lead-free solder alloy composition, a solder ball including the same, a solder paste including the lead-free solder alloy composition, a semiconductor device including a hybrid bonding structure including the lead-free solder alloy composition, and a method of manufacturing a solder paste including the lead-free solder alloy composition.
Recently, as the electronics industry advances and the demands of consumers increase, the small size and high performance of semiconductor devices have been considered.
The embodiments may be realized by providing a lead-free solder alloy composition including a lead-free solder alloy; and a flower-shaped metal nano-particle including a metal core and protrusion portions extending from a surface of the metal core, wherein the metal core and the protrusion portions of the metal nano-particle include only one metal element.
The embodiments may be realized by providing a solder paste including the lead-free solder alloy composition according to an embodiment.
The embodiments may be realized by providing a solder ball including the lead-free solder alloy composition according to an embodiment.
The embodiments may be realized by providing a method of manufacturing a solder paste, the method including immersing a lead-free solder alloy and a metal nano-particle in a hexane solution; mixing the lead-free solder alloy with the metal nano-particle by performing an ultrasonic processing; removing the hexane solution by performing a thermal treatment; and mixing a flux with the lead-free solder alloy and the metal nano-particle after performing the ultrasonic processing, wherein the metal nano-particle includes a flower-shaped metal nano-particle including a metal core and protrusion portions extending from a surface of the metal core, and the metal core and the protrusion portions include only one metal element.
The embodiments may be realized by providing a semiconductor device including a printed circuit board (PCB); a semiconductor part; and a hybrid bonding structure between the PCB and the semiconductor part, the hybrid bonding structure including a solder paste, wherein the solder paste includes a lead-free solder alloy composition, the lead-free solder alloy composition includes a lead-free solder alloy and a flower-shaped metal nano-particle including a metal core and protrusion portions extending from a surface of the metal core, and the metal core and the protrusion portions each include only one metal element.
Features will be apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which:
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The lead-free solder alloy 12 may be a lead-free solder alloy including tin (Sn). In an implementation, the lead-free solder alloy 12 may include, e.g., a tin-bismuth (Sn—Bi) alloy, a tin-bismuth-silver (Sn—Bi—Ag) alloy, or a tin-bismuth-indium (Sn—Bi—In) alloy. As used herein, the term “or” is not an exclusive term, e.g., “A or B” would include A, B, or A and B. In an implementation, when the lead-free solder alloy 12 is an Sn—Bi alloy, a wt % of Bi may be about 35 wt % to about 70 wt % and a wt % of Sn may be a remainder or balance amount, based on a total weight of the Sn—Bi. In an implementation, when the lead-free solder alloy 12 is a Sn—Bi—Ag alloy, a wt % of Bi may be about 35 wt % to about 75 wt %, a wt % of Ag may be about 0.1 wt % to about 20 wt %, and a wt % of Sn may be a remainder or balance amount, based on a total weight of the Sn—Bi—Ag. In an implementation, when the lead-free solder alloy 12 is an Sn—Bi—In alloy, a wt % of Bi may be about 15 wt % to about 65 wt %, a wt % of In may be about 5 wt % to about 75 wt %, and a wt % of Sn may be a remainder or balance amount, based on a total weight of the Sn—Bi—In.
The metal nano-particle 14 may be a flower-shaped metal nano-particle 14 including a metal core and protrusion portions extending from a surface of the metal core. In an implementation, the metal core and the protrusion portions may include only one metal element (e.g., may be a uniform, homogenous material consisting of a single metal element). In an implementation, the metal element may include silver (Ag), gold (Au), platinum (Pt), copper (Cu), or tungsten (W). In an implementation, the metal nano-particle 14 may be a flower-shaped metal nano-particle 14 that includes a metal core including only (e.g., consisting of) Ag and protrusion portions including only (e.g., consisting of) Ag and extending from the surface of the metal core. In an implementation, the metal nano-particle 14 may be included in the composition in an amount of, e.g., about 0.1 wt % to about 2.0 wt %, about 0.4 wt % to about 1.5 wt %, or about 1.0 wt % to about 1.5 wt %, based on a total weight of the lead-free solder alloy composition 10. In an implementation, the metal nano-particle 14 may be included in an amount of about 1.0 wt %, based on the total weight of the lead-free solder alloy composition 10. In an implementation, the metal core may have a spherical shape. In an implementation, a diameter of the metal core may be about 200 nm to about 500 nm. In an implementation, a length of each of the protrusion portions may be about 9 nm to about 22 nm. Here, a length of each of the protrusion portions may denote a length of each of the protrusion portions in a direction vertical to (e.g., outward from) the surface of the metal core. In an implementation, the protrusion portions may melt at about 100° C. or about 140° C. or about 120° C. to about 140° C. In an implementation, the protrusion portions may melt at about 140° C.
Some other lead-free solder alloy compositions may include metal nano-particles having a spherical shape. In this case, the metal nano-particles having a spherical shape may have a relatively high adhesion force, and the metal nano-particles may agglomerate in the other lead-free solder alloy compositions and may thus not be dispersed well. Due to this, in a case where a soldering process is performed on a solder paste including the other lead-free solder alloy compositions and a solder ball, Ag3Sn formed by the soldering process may not be dispersed well and may be coarsened. Therefore, the mechanical properties of a solder including the other lead-free solder alloy compositions may be reduced, and misalignment between the solder paste and the solder ball could occur when performing a soldering process. In an implementation, the lead-free solder alloy composition 10 according to an embodiment may include the flower-shaped metal nano-particles 14. In this case, the flower-shaped metal nano-particles 14 may include the protrusion portions, and the flower-shaped metal nano-particles 14 may have a relatively low adhesion force and thus may not readily agglomerate in the lead-free solder alloy composition 10 and instead may be dispersed well. In an implementation, in a case where a soldering process is performed on a solder paste including a solder ball and the lead-free solder alloy composition 10 according to an embodiment, Ag3Sn formed by the soldering process may be dispersed well and formed. Accordingly, the mechanical properties of a solder may be improved, and misalignment between the solder paste and the solder ball may be prevented when performing a soldering process.
The lead-free solder alloy composition 10 described above may be provided in the form of a solder ball or a solder paste.
The solder paste may include about 3 wt % to about 25 wt % of a flux, with respect to all of the lead-free solder alloy composition 10 (e.g., based on a total weight of the solder paste). In an implementation, the flux may include, e.g., a RMA-type paste flux and may be liquid at room temperature.
A compound of the lead-free solder alloy composition 10 and the flux may form a paste phase at room temperature.
The solder ball may be about 50 μm to about 1,000 μm in diameter and may be provided by molding the lead-free solder alloy composition 10 in a spherical shape.
In an implementation, the lead-free solder alloy composition 10 may be provided as an arbitrary icon, e.g., a cream, a bar, or a wire.
The following Examples and Comparative Examples are provided in order to highlight characteristics of one or more embodiments, but it will be understood that the Examples and Comparative Examples are not to be construed as limiting the scope of the embodiments, nor are the Comparative Examples to be construed as being outside the scope of the embodiments. Further, it will be understood that the embodiments are not limited to the particular details described in the Examples and Comparative Examples.
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In an implementation, the metal nano-particle may be a flower-shaped metal nano-particle including a metal core and protrusion portions extending from a surface of the metal core. In an implementation, the metal core and the protrusion portions may include only Ag. In an implementation, a wt % of the metal nano-particle may be about 0.4 wt % to about 2.0 wt %, with respect to a total weight of the lead-free solder alloy composition. The metal nano-particle may be manufactured through the following process. First, a silver nitrate solution may be manufactured by adding silver nitrate to deionized water, an ammonium citrate dibasic solution may be manufactured by adding ammonium citrate dibasic to deionized water, and a boric acid solution may be manufactured by adding boric acid to deionized water. Subsequently, the silver nitrate solution, the ammonium citrate dibasic solution, and the boric acid solution may be heated to a temperature of about 50° C., and the solutions may be mixed. Subsequently, a mixed solution where the solutions are mixed may be stirred for about 2 sec at a temperature of about 50° C., and an ammonia solution may be added until the mixed solution is transparent. Subsequently, an L-ascorbic acid solution having the same concentration as that of the silver nitrate solution may be manufactured by adding L-ascorbic acid to deionized water, and then, the L-ascorbic acid solution may be added to the mixed solution to which the ammonia solution is added and the mixed solution to which the L-ascorbic acid is added may be stirred for about 30 min, thereby manufacturing the metal nano-particle. The mixed solution including the manufactured metal nano-particle may be vacuum-filtered, and then, by performing a cleaning process using deionized water, the metal nano-particle in a solid powder form may be obtained.
Subsequently, in order to mix metal nano-particles with a lead-free solder alloy immersed in the hexane solution, ultrasound or ultrasonic processing may be performed on the lead-free solder alloy and the metal nano-particles in operation S120. In an implementation, the ultrasonic processing may be performed by using tip-type ultrasound waves. In an implementation, the ultrasonic processing may be performed for, e.g., about 1 min to about 3 min. In an implementation, the ultrasonic processing may be performed, e.g., 6 times to 12 times or 8 times to 10 times. In an implementation, the ultrasonic processing may be performed 9 times, each time of the ultrasonic processing may be performed for about 2 min. In an implementation, the ultrasonic processing may be performed with intervals of about 5 sec to about 15 sec therebetween. In an implementation, the ultrasonic processing may be performed 9 times and with an interval of about 10 sec between each time the ultrasonic processing is performed.
Subsequently, in order to remove the hexane solution, thermal treatment may be performed on the hexane (in which the lead-free solder alloy has been mixed with the metal nano-particles) in operation S130. In an implementation, the thermal treatment may be performed at about 30° C. to about 50° C. In an implementation, the thermal treatment may be performed for about 15 min to about 25 min. In an implementation, the thermal treatment may be performed at a temperature of about 40° C. and may be performed for about 20 min. The hexane solution may be removed by the thermal treatment.
Finally, the lead-free solder alloy and the metal nano-particles (which have been mixed with each other) may be mixed with flux. In an implementation, the lead-free solder alloy and the metal nano-particles may be mixed with the flux using a Thinky mixer. In an implementation, the Thinky mixer may rotate for about 1 min at a rotational speed of about 1,000 rpm to mix the flux with the lead-free solder alloy and the metal nano-particles. As operation S140 is performed, a solder paste including the lead-free solder alloy composition according to an embodiment may be manufactured.
Other lead-free solder alloy compositions may include metal nano-particles having a spherical shape. In this case, the metal nano-particles having a spherical shape may have a relatively high adhesion force, and the metal nano-particles may agglomerate in the other lead-free solder alloy composition and may thus not be dispersed well. Due to this, if a soldering process were to be performed using a solder paste including the other lead-free solder alloy composition and a solder ball, Ag3Sn formed by the soldering process may not be dispersed well and could be coarsened. Therefore, the mechanical properties of a solder including the other lead-free solder alloy composition may be reduced, and misalignment between the solder paste and the solder ball may occur when performing a soldering process. On the other hand, the lead-free solder alloy composition 10 according to an embodiment may include flower-shaped metal nano-particles. In this case, the flower-shaped metal nano-particles include protrusion portions, and the flower-shaped metal nano-particles may have a relatively low adhesion force and may thus may not agglomerate well in the lead-free solder alloy composition 10, and may be dispersed well. Therefore, in a case where a soldering process is performed using a solder paste including a solder ball and the lead-free solder alloy composition 10 according to an embodiment, Ag3Sn formed by the soldering process may be dispersed well and formed. Accordingly, the mechanical properties of a solder may be improved, and misalignment between the solder paste and the solder ball may be prevented when performing a soldering process.
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The semiconductor part 111 may include a plurality of first pads 113. The plurality of first pads 113 may be buried in the semiconductor part 111. In an implementation, an upper surface of each of the plurality of first pads 113 may be coplanar with an upper surface of the semiconductor part 111. A passivation layer 120 may be on the upper surface of the semiconductor part 111.
The solder balls 130 may be on the plurality of first pads 113 of the semiconductor part 111. In an implementation, the solder balls 130 may overlap the plurality of first pads 113 in a direction vertical to the upper surface of the semiconductor part 111.
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Some other lead-free solder alloy compositions may include metal nano-particles having a spherical shape. In this case, the metal nano-particles having a spherical shape may have a relatively high adhesion force, and the metal nano-particles may agglomerate in the other lead-free solder alloy compositions and may thus not be dispersed well. Due to this, in a case where a soldering process is performed on a solder paste including the other lead-free solder alloy compositions and a solder ball, Ag3Sn formed by the soldering process may not be dispersed well and may be coarsened. Therefore, the mechanical properties of a solder including the other lead-free solder alloy compositions may be reduced, and misalignment between the solder paste and the solder ball could occur when performing a soldering process. On the other hand, the lead-free solder alloy composition 10 according to an embodiment may include the flower-shaped metal nano-particles. In this case, the flower-shaped metal nano-particles may include protrusion portions, and the flower-shaped metal nano-particles may have a relatively low adhesion force and may thus may not agglomerate well in the lead-free solder alloy composition 10 and may be dispersed well. Therefore, in a case where a soldering process is performed on a solder paste including a solder ball and the lead-free solder alloy composition 10 according to an embodiment, Ag3Sn formed by the soldering process may be dispersed well and formed. Accordingly, the mechanical properties of a solder may be improved, and misalignment between the solder paste and the solder ball may be prevented when performing a soldering process. As a result, the mechanical properties of a plurality of hybrid bonding structures formed by performing a soldering process on the solder paste and the solder ball may be improved, and thus, the structure reliability of a semiconductor device including the hybrid bonding structures may be improved.
By way of summation and review, a plurality of semiconductor devices may be highly integrated and mounted on one substrate. In this case, in order to prevent a reduction in performance of a semiconductor device caused by thermal damage and the occurrence of a defect such as warpage of a semiconductor device, a solder alloy composition may facilitate mounting of a semiconductor device on a substrate at a low temperature.
One or more embodiments may provide a lead-free solder alloy composition including a lead-free solder alloy and a metal nano-particle.
One or more embodiments may provide a lead-free solder alloy composition having excellent mechanical properties.
One or more embodiments may provide a method of manufacturing a solder paste including a lead-free solder alloy composition having excellent mechanical properties.
One or more embodiments may provide a semiconductor device including a hybrid bonding structure formed by a solder paste including a lead-free solder alloy composition having excellent mechanical properties.
Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0123648 | Sep 2022 | KR | national |
