Nanocomposite solder containing two-dimensional nanomaterial and soldering method for nanocomposite solder using reflow operation

Abstract

One embodiment of the present invention provides a nanocomposite solder containing a two-dimensional nanomaterial and a soldering method for the nanocomposite solder using a reflow operation. The nanocomposite solder according to an embodiment of the present invention confines the two-dimensional nanomaterial in a tin-containing paste, thereby reducing the grain size of the solder and enhancing hardness. As a result, the nanocomposite solder has enhanced mechanical properties and thermal conductivity, thereby exhibiting enhanced heat dissipation characteristics.

Description

Nanocomposite solder containing two-dimensional nanomaterials and soldering method of nanocomposite solder through reflow process

[0001] The present invention relates to a nanocomposite solder containing a two-dimensional nanomaterial and a soldering method of the nanocomposite solder through a reflow process.

[0002] Recently, the installation of electronic components in automobiles has been increasing to enhance convenience and safety. These automotive electronic components require high reliability, and to achieve this, the reliability of the solder materials connecting the electronic components to the printed circuit board is crucial.

[0003] In particular, as the use of lead solder is regulated in the automotive electrical components field, ternary alloys of tin, silver, and copper are widely used as substitutes for lead solder. However, automotive electrical components operated in harsh environments require solder materials with higher reliability.

[0004] To improve reliability, a technology has been developed to alloy tin-silver-copper alloys by adding various microelements, and another technology is being developed to mix nanoparticles into solder.

[0005] As part of this technological development, the development of nanocomposite solder compositions containing carbon nanoparticles is underway. By doping CNTs or graphene into lead-free solder, the carbon particles located between the grains form smaller and more uniform crystal structures due to the pinning effect, which can enhance mechanical performance such as structural refinement, inhibition of intermetallic compound growth, improvement of shear strength or hardness, and expansion of dislocation density. In addition to the mechanical aspect, it can improve the current density and electrical properties in the solder alloy, and as the size of the carbon particles decreases, the pinning effect is maximized, which can improve the mechanical and electrical properties.

[0006] In addition, conventional solder technology has a problem in that when a crack occurs in the solder, the thermal conductivity of the solder decreases and the crack increases further, which ultimately causes destruction of the solder or accelerates deterioration of the silicon (Si) die because the heat generated in the silicon (Si) die is not well dissipated.

[0007] In addition, as the operating temperature of silicon carbide (SiC) power semiconductors, which are key components of electric vehicles, rises to 250°C, high-temperature bonding such as copper (Cu) sintering, silver (Ag) sintering, TLP (Transient Liquid Phase) bonding, and TLPS (Transient Liquid Phase Sintering) is required. At this time, since the power semiconductor module is a multilayer structure in which materials with different coefficients of thermal expansion (CTE), such as metals, ceramics, and polymers, are bonded, stress is generated due to different stress distributions within the module, and this stress difference is a major factor in lowering the reliability of the power semiconductor module.

[0008] The heat generated from the silicon die is transferred to the heat sink through the solder joints adjacent to the silicon die, the DBC (Direct bonded copper) substrate, and the base plate, and the heat is dissipated. The IGBT (Insulated gate bipolar transistor) is a power device applied in various industrial fields such as automobiles, electric vehicles, aviation, home appliances, and various other fields. It is an important device for changing, controlling, and transmitting electric power, and is a core component of electric vehicles and hybrid electric vehicles.

[0009] Therefore, it is necessary to develop a solder that can effectively dissipate the generated heat and prevent deterioration of the silicon (Si) die.

[0010] This patent is the result of a local government-university collaboration-based regional innovation project (Chosun University), funded by the Ministry of Education and supported by the National Research Foundation of Korea in 2023. (Project Management Number: 2021RIS-002)

[0011] This patent was conducted with the support of the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT (MSIT) (Dankook University) (No. NRF-2022R1A2C2006379).

[0012] This patent was conducted with the support of the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT (MSIT) (No. RS-2023-00236572).

[0013] <Prior Art Document> Republic of Korea Patent No. 10-1962107

[0014] The technical problem to be achieved by the present invention is to provide a nanocomposite solder containing a two-dimensional nanomaterial and a soldering method of the nanocomposite solder through a reflow process.

[0015] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0016] To achieve the above technical task, one embodiment of the present invention provides a nanocomposite solder.

[0017] According to one embodiment of the present invention, the nanocomposite solder comprises a tin (Sn)-based solder paste; and a two-dimensional nanomaterial, wherein the two-dimensional nanomaterial can be impregnated into the tin (Sn)-based solder paste.

[0018] Additionally, according to one embodiment of the present invention, the tin (Sn)-based solder paste may include at least one selected from the group consisting of Sn-58Bi paste, Sn-3.0Ag-0.5Cu paste, Sn-3.5Ag paste, and Sn-1.0Ag-0.7Cu paste.

[0019] In addition, according to one embodiment of the present invention, the two-dimensional nanomaterial is MXene, titanium-based MXene (Ti3C2, Ti2C, Ti3(C,N)2, Ti2N, Ti4N3), molybdenum-based MXene (Mo2C, Mo2N), vanadium-based MXene (V2C, V4C3), tungsten-based MXene (W 1.3 C), niobium-based MXene (Nb2C, Nb 1.3 It may include at least one selected from the group consisting of C, Nb4C3), zirconium-based MXene (Zr3C2), tantalum-based and alloy-based MXene ((Ti,V)2C, (Ti,Nb)2C, (Ti,V)3C2, (Nb,V)4C3, (Ti,Nb)4C3, (Nb,Zr)4C3, (Ti,Nb)4C3).

[0020] Additionally, according to one embodiment of the present invention, the diameter of the two-dimensional nanomaterial may be 0.1 μm to 10 μm.

[0021] Additionally, according to one embodiment of the present invention, the two-dimensional nanomaterial may be included in an amount of 0.2 wt% to 10 wt% relative to the total nanocomposite solder content.

[0022] Additionally, according to one embodiment of the present invention, the two-dimensional nanomaterial can be dispersed within the tin (Sn)-based solder paste.

[0023] Additionally, according to one embodiment of the present invention, the grain size of the nanocomposite solder may be 0.1 μm to 100 μm.

[0024]

[0025] In order to achieve the above technical task, another embodiment of the present invention provides a soldering method using a reflow process.

[0026] A soldering method using the reflow process according to one embodiment of the present invention comprises the steps of preparing a first substrate having a nanocomposite solder positioned on a surface thereof and a second substrate spaced apart from the first substrate; and the step of performing a reflow process by irradiating a laser beam on the nanocomposite solder positioned in a space between the first substrate and the second substrate to perform soldering, wherein the temperature of a processing area irradiated with the laser beam can be gradually lowered.

[0027] Additionally, according to one embodiment of the present invention, the temperature of the reflow process can be cooled from a temperature range of 160°C to 140°C to a temperature range of 140°C to 135°C depending on the temperature setting of the equipment.

[0028] Additionally, according to one embodiment of the present invention, cooling can be stopped when the grain size of the nanocomposite solder becomes 0.1 μm to 10 μm.

[0029] Additionally, according to one embodiment of the present invention, the grain size of the nanocomposite solder may be 0.1 μm to 100 μm.

[0030] A nanocomposite solder according to one embodiment of the present invention has the effect of improving mechanical properties by entrapping a two-dimensional nanomaterial in a paste containing tin, thereby improving hardness through a reduction in the grain size of the solder, and improving thermal conductivity, thereby improving heat dissipation characteristics.

[0031] In addition, the soldering method using a nanocomposite solder according to one embodiment of the present invention has the effect of minimizing the amount of heat input during the process by gradually lowering the reflow temperature through the reflow process and soldering while confining the two-dimensional nanomaterial inside without releasing it.

[0032] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0033] Figure 1 is an actual photograph of a tin-based paste (comparative example) and a nanocomposite solder including a two-dimensional nanomaterial (example).

[0034] Figure 2 is a schematic diagram showing the particle diameter of a two-dimensional nanomaterial of one embodiment of the present invention.

[0035] Figure 3 is an actual photograph showing the shape of a nanocomposite solder (Type 3) containing a two-dimensional nanomaterial of one embodiment of the present invention according to the number of mixing cycles.

[0036] Figure 4 is an actual photograph showing the shape of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial of one embodiment of the present invention according to the number of mixing cycles.

[0037] Figure 5 is an SEM image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0038] Figure 6 is an SEM image showing the reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention using a furnace.

[0039] Figure 7 is an EDX Mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0040] Figure 8 is a map sum spectrum image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0041] Figure 9 is an EDX mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0042] Figure 10 is an EDX mapping image showing the temperature-dependent reflow pattern inside the solder of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0043] Figure 11 is an SEM image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0044] Figure 12 is an EDX Mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0045] Figure 13 is an EDX line scan image of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial of one embodiment of the present invention, magnified 10,000 times.

[0046] Figure 14 is an EDX line scan image of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial of one embodiment of the present invention, magnified 20,000 times.

[0047] Figure 15 is an EDX Mapping showing the reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention at different temperatures (135°C).

[0048] Figure 16 is an EDX line scan image and graph of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0049] Figure 17 is an EDX mapping showing the reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention at different temperatures (140°C).

[0050] Figure 18 is an EDX Point scan image and graph of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0051] FIG. 19 is an optical image and Vickers hardness graph of a nanocomposite solder (Type 3) including SnBi solder and a two-dimensional nanomaterial as an embodiment of the present invention.

[0052] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0053] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another member in between. Furthermore, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0054] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0055]

[0056] Below, the present invention will be described with reference to the drawings presented in this specification. Note that the drawings may be exaggerated to illustrate the features of the present invention. In such cases, it is preferable to interpret them in light of the overall intent of this specification.

[0057]

[0058] A nanocomposite solder according to one embodiment of the present invention is described.

[0059] A nanocomposite solder according to one embodiment of the present invention comprises a tin (Sn)-based solder paste; and a two-dimensional nanomaterial, wherein the two-dimensional nanomaterial can be impregnated into the tin (Sn)-based solder paste.

[0060] First, the present invention may include a tin (Sn)-based solder paste.

[0061] At this time, the tin (Sn)-based solder paste used in the present invention may include at least one selected from the group consisting of Sn-58Bi paste, Sn-3.0 Ag-0.5 Cu paste, Sn-3.5Ag paste, and Sn-1.0Ag-0.7Cu paste.

[0062] At this time, the present invention is not only applicable to the above-described type of paste, but may also be applicable to other types of paste.

[0063] For example, the paste composition may further include metals such as Ni, Au, Pd, Pt, Fe, and Co.

[0064] Next, the present invention may include a two-dimensional nanomaterial.

[0065] At this time, the two-dimensional nanomaterials used in the present invention are MXene, titanium-based MXene (Ti3C2, Ti2C, Ti3(C,N)2, Ti2N, Ti4N3), molybdenum-based MXene (Mo2C, Mo2N), vanadium-based MXene (V2C, V4C3), tungsten-based MXene (W 1.3 C), niobium-based MXene (Nb2C, Nb1.3 C, Nb4C3), zirconium-based MXene (Zr3C2), tantalum-based and alloy-based MXene ((Ti,V)2C, (Ti,Nb)2C, (Ti,V)3C2, (Nb,V)4C3, (Ti,Nb)4C3, (Nb,Zr)4C3, (Ti,Nb)4C3).

[0066] At this time, the present invention uses Mxene as the two-dimensional nanomaterial, which is a type of graphene and is named by synthesizing M of MAX and ene of X graphene.

[0067] The above MXenes, unlike general graphene, have a band structure similar to a semiconductor, making it possible to implement semiconductor properties.

[0068] The greatest advantages of the above MXenes are their high electrical conductivity (thermal conductivity) and hydrophilicity. Furthermore, their size, measured in nanometers (nm), is advantageous for semiconductor miniaturization.

[0069] At this time, the diameter of the two-dimensional nanomaterial used in the present invention may be 0.1 μm to 10 μm.

[0070] At this time, the reason why the diameter of the two-dimensional nanomaterial is 0.1 μm to 10 μm is that if the diameter is less than 0.1 μm, there may be a problem of agglomeration of nanomaterial particles, and if the diameter exceeds 10 μm, there may be a problem of difficulty in dispersing the nanomaterial particles within the nanocomposite solder.

[0071] At this time, the two-dimensional nanomaterial may be included in an amount of 0.2 wt% to 10 wt% relative to the total nanocomposite solder content.

[0072] The reason why the content of the above two-dimensional nanomaterial is 0.2 wt% to 10 wt% is that when it is less than 0.2 wt%, there may be a problem that the mechanical strength and heat dissipation properties of the nanocomposite solder are not improved by the nanomaterial particles, and when it exceeds 10 wt%, there may be a problem that the nanomaterial particles aggregate within the nanocomposite solder and it is difficult to form solder balls.

[0073] At this time, the two-dimensional nanomaterial of the present invention can be dispersed within the tin (Sn)-based solder paste.

[0074] At this time, a reflow process can be used to disperse the above two-dimensional nanomaterial within a tin (Sn)-based solder paste and solder it.

[0075] At this time, if excessive soldering conditions are applied during soldering using the reflow process, there may be a problem of release of maxine due to solder melting, or decrease in hardness due to increase in grain size due to excessive heat input.

[0076] Accordingly, the present invention has discovered a minimum solderable temperature while confining MXene within the solder paste without releasing it, by lowering the temperature of the reflow process, which is a soldering condition, from a temperature range of 160°C to 140°C to a temperature range of 140°C to 135°C.

[0077] In this case, when the temperature of the reflow process is lowered, the grain size is minimized, which has the effect of increasing the hardness.

[0078] At this time, the grain size of the nanocomposite solder of the present invention is characterized by being 0.1 μm to 100 μm.

[0079] Since the crystal grain size can be adjusted to a very small size of 0.1 μm to 10 μm when producing a composite solder, the hardness of the present invention can be increased.

[0080] At this time, as a method of reducing the temperature of the reflow process of the present invention, it can be performed by adjusting the temperature setting of the reflow equipment.

[0081] For this, specific process conditions are described in the nanocomposite solder manufacturing method below.

[0082]

[0083] In addition, a method for manufacturing a nanocomposite solder according to another embodiment of the present invention is described.

[0084] A method for manufacturing a nanocomposite solder according to one embodiment of the present invention may include a step of manufacturing a mixture by putting a tin (Sn)-based solder paste and a two-dimensional nanomaterial into a mixer and then mixing them.

[0085] At this time, the tin (Sn)-based solder paste used in the present invention may include at least one selected from the group consisting of Sn-58Bi paste, Sn-3.0 Ag-0.5 Cu paste, Sn-3.5Ag paste, and Sn-1.0Ag-0.7Cu paste.

[0086] At this time, the present invention is not only applicable to the above-described type of paste, but may also be applicable to other types of paste.

[0087] For example, the paste composition may further include metals such as Ni, Au, Pd, Pt, Fe, and Co.

[0088] Additionally, the present invention may include a two-dimensional nanomaterial.

[0089] At this time, the two-dimensional nanomaterials used in the present invention are MXene, titanium-based MXene (Ti3C2, Ti2C, Ti3(C,N)2, Ti2N, Ti4N3), molybdenum-based MXene (Mo2C, Mo2N), vanadium-based MXene (V2C, V4C3), tungsten-based MXene (W 1.3 C), niobium-based MXene (Nb2C, Nb 1.3It may include at least one selected from the group consisting of C, Nb4C3), zirconium-based MXene (Zr3C2), tantalum-based and alloy-based MXene ((Ti,V)2C, (Ti,Nb)2C, (Ti,V)3C2, (Nb,V)4C3, (Ti,Nb)4C3, (Nb,Zr)4C3, (Ti,Nb)4C3).

[0090] The above two-dimensional nanomaterial may be included in an amount of 0.2 wt% to 10 wt% relative to the total mixture content.

[0091] At this time, the two-dimensional nanomaterial of the present invention is characterized in that it is dispersed within the tin (Sn)-based solder paste, and the tin (Sn)-based solder paste and the two-dimensional nanomaterial are introduced into a paste mixer and mixed at a process speed of 800 rpm and a rotation speed of 500 rpm.

[0092] At this time, the number of mixing times can be 1 to 5 times for 1 minute each, and is not limited to the number of mixing times described above, and mixing can be performed until the two-dimensional nanomaterial is sufficiently dispersed within the tin (Sn)-based solder paste.

[0093]

[0094] In addition, a soldering method using a reflow process according to another embodiment of the present invention is described.

[0095] A soldering method according to one embodiment of the present invention comprises the steps of: preparing a first substrate having a nanocomposite solder positioned on a surface thereof and a second substrate spaced apart from the first substrate; and performing a reflow process by irradiating a laser beam on the nanocomposite solder positioned in a space between the first substrate and the second substrate to perform soldering, wherein the temperature of a processing area irradiated with the laser beam can be gradually lowered.

[0096] First, the present invention can prepare a first substrate having a nanocomposite solder positioned on the surface and a second substrate spaced apart from the first substrate.

[0097] At this time, the types of the first substrate and the second substrate on which the nanocomposite solder is positioned on the surface may be the same or different.

[0098] Next, the present invention may include a step of soldering by performing a reflow process on a nanocomposite solder positioned in a space between the first substrate and the second substrate.

[0099] At this time, the present invention performs a reflow process at a low temperature to solve the problem of a process in which a two-dimensional nanomaterial is released to the outside together with the flux when a conventional two-dimensional nanocomposite solder containing a two-dimensional nanomaterial is excessively soldered above the melting point, and when a reflow process is performed, an effect can be obtained in which the two-dimensional nanomaterial exists inside the nanocomposite solder without being released while being soldered.

[0100] At this time, the present invention can cool the temperature of the reflow process from a temperature range of 160°C to 140°C to a temperature range of 140°C to 135°C.

[0101] At this time, the temperature of the reflow process can be cooled by performing a method of setting the setting temperature of the reflow equipment, and the temperature is characterized by being lowered in steps.

[0102] For example, the temperature of the reflow process can be gradually lowered from 160°C to 140°C, from 140°C to 138°C, from 138°C to 136°C, and from 136°C to 135°C.

[0103] At this time, a specific method for gradually lowering the temperature of the reflow process is to set an accurate temperature by repeating the trial and error method.

[0104] In addition, the principle of reducing the grain size by lowering the temperature of the reflow process is that the particles of the nanocomposite solder reduce the soldering temperature and time, thereby reducing the total amount of energy input during soldering, thereby preventing excessive soldering and minimizing grain growth.

[0105] Accordingly, the soldering method using the reflow process of the present invention has the effect of minimizing the amount of heat input during the process compared to the excessive soldering process in which the nanocomposite solder is heated above the melting point.

[0106]

[0107] Hereinafter, the present invention will be described in more detail through manufacturing examples and experimental examples. These comparative examples, manufacturing examples, and experimental examples are intended solely to illustrate the present invention, and the scope of the present invention is not limited by these comparative examples, manufacturing examples, and experimental examples.

[0108]

[0109] Comparative Example 1: Sn-3.0 Ag-0.5 Cu paste (Type 1)

[0110] In Comparative Example 1, commercial Sn-3.0 Ag-0.5 Cu paste was used.

[0111]

[0112] Comparative Example 2: Sn-58Bi paste (Type 2)

[0113] In Comparative Example 2, commercial Sn-58Bi paste was used.

[0114]

[0115] Manufacturing example

[0116] First, a mixture was prepared by adding 0.1 g of powder-type MXene to 50 g of Sample 3 (Type 3) to Sample 9 (Type 9) pastes with different metal particle sizes as shown in Table 1 below.

[0117] Next, the mixture was adjusted to a process speed of 800 rpm and a rotation speed of 500 rpm of the paste mixer, and Sn-58Bi paste-maxene nanocomposite solders of Type 3 to Type 9 were manufactured according to the mixing number of times in Table 1 below.

[0118] At this time, the above mixing was performed once for 1 minute.

[0119] Sample (Type) Particle size (particle size) Mixing times 325~45μm 5 times 91~6μm 3 times

[0120]

[0121] Experimental Example 1: Nanocomposite solder manufacturing verification experiment

[0122] In this experimental example 1, the manufacturing of nanocomposite solder is confirmed with reference to FIGS. 1 to 4.

[0123] Figure 1 is an actual photograph of a tin-based paste (comparative example) and a nanocomposite solder including a two-dimensional nanomaterial (example).

[0124] Fig. 1(a) is an image observed after the reflow process of Sn-3.0 Ag-0.5 Cu paste, Fig. 1(b) is an image observed after the reflow process of Sn-58Bi paste-MXene nanocomposite solder, Fig. 1(c) is an image observed after the reflow process of Sn-3.0 Ag-0.5 Cu paste, and Fig. 1(d) is an image observed after the reflow process of Sn-58Bi paste-MXene nanocomposite solder.

[0125] Referring to Figures 1(b) and 1(d), the shape of black spots is observed, confirming that the nanocomposite solder contains maxene.

[0126] In order to prevent the release of MXene from the nanocomposite solder as shown in Fig. 1(b) and Fig. 1(d), the present invention controlled the number of mixing times.

[0127] Figure 2 is a schematic diagram showing the particle diameter of a two-dimensional nanomaterial of one embodiment of the present invention.

[0128] Figure 3 is an actual photograph showing the morphology of a nanocomposite solder (Type 3) containing a two-dimensional nanomaterial according to one embodiment of the present invention according to the number of mixing cycles. Here, it can be confirmed that the degree of dispersion of the nanomaterial within the composite solder gradually improves as the number of mixing cycles increases.

[0129] Figure 4 is an actual photograph showing the morphology of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial according to one embodiment of the present invention according to the number of mixing cycles. Here, it can be confirmed that the degree of dispersion of the nanomaterial within the composite solder gradually improves as the number of mixing cycles increases.

[0130] Referring to FIGS. 4 and 5, the process of soldering a Type 3 nanocomposite solder including a two-dimensional nanomaterial as the mixing number increases and the temperature increases is illustrated.

[0131]

[0132] Experimental Example 2: Experiment to Confirm Nanocomposite Solder Characteristics

[0133] In this Experimental Example 2, the microstructural changes due to the addition of two-dimensional nanomaterials were observed through SEM / EDX analysis inside the nanocomposite solder, and the Vickers hardness was evaluated to evaluate the mechanical property changes.

[0134] Figure 5 is an SEM image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0135] Figure 6 is an SEM image showing the reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention using a furnace.

[0136] Referring to FIGS. 5 and 6, it can be confirmed that the present invention is a process in which soldering is performed when the temperature is gradually increased to 140°C, although soldering is hardly performed at 130°C.

[0137]

[0138] Figure 7 is an EDX Mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0139] Figure 8 is an image of the EDX composition analysis results showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0140] Figure 9 is an EDX mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0141] Figure 10 is an EDX mapping image showing the temperature-dependent reflow pattern inside the solder of a nanocomposite solder (Type 3) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0142] Referring to FIGS. 7 to 10, the present invention can confirm that the two-dimensional nanomaterial exists on the outer surface of nanocomposite solder particles or inside the solder, such as flux, at a low temperature for soldering, such as 130°C.

[0143]

[0144] Figure 11 is an SEM image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0145] Figure 12 is an EDX Mapping image showing the temperature-dependent reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0146] Referring to FIGS. 11 and 12, it can be confirmed that the present invention is a process in which soldering is gradually performed as the temperature increases from 130°C to 140°C.

[0147] Figure 13 is an EDX line scan image of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial of one embodiment of the present invention, magnified 10,000 times.

[0148] Figure 14 is an EDX line scan image of a nanocomposite solder (Type 9) containing a two-dimensional nanomaterial of one embodiment of the present invention, magnified 20,000 times.

[0149] Referring to FIGS. 13 and 14, the present invention can confirm that a two-dimensional nanomaterial exists on the outer surface of a nanocomposite solder particle or between fluxes.

[0150]

[0151] Figure 15 is an EDX Mapping showing the reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention at different temperatures (135°C).

[0152] Figure 16 is an EDX line scan image and graph of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0153] Figure 17 is an EDX mapping showing the reflow pattern of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention at different temperatures (140°C).

[0154] Figure 18 is an EDX Point scan image and graph of a nanocomposite solder (Type 9) including a two-dimensional nanomaterial of one embodiment of the present invention.

[0155] Referring to FIGS. 15 to 18, the present invention can confirm that a two-dimensional nanomaterial exists on the outer surface of a nanocomposite solder particle or between fluxes.

[0156]

[0157] FIG. 19 is an optical image and Vickers hardness graph of a nanocomposite solder (Type 3) including SnBi solder and a two-dimensional nanomaterial as an embodiment of the present invention.

[0158] Referring to Fig. 19, it can be confirmed through Figs. 19(a) and (b) that the mixed vacancy structure of Sn and Bi phases of the nanocomposite solder including the two-dimensional nanomaterial is refined, and through Fig. 19(c), it can be confirmed that the mechanical strength is improved as the numerical value increases from 33.33 HV to 36.19 HV.

[0159]

[0160] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0161] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. Tin (Sn) based solder paste; and Including two-dimensional nanomaterials, A nanocomposite solder characterized in that the above two-dimensional nanomaterial is impregnated into the tin (Sn)-based solder paste.

2. In paragraph 1, A nanocomposite solder characterized in that the above tin (Sn)-based solder paste comprises at least one selected from the group consisting of Sn-58Bi paste, Sn-3.0 Ag-0.5 Cu paste, Sn-3.5Ag paste, and Sn-1.0Ag-0.7Cu paste.

3. In paragraph 1, The above two-dimensional nanomaterials include MXene, titanium-based MXene (Ti3C2, Ti2C, Ti3(C,N)2, Ti2N, Ti4N3), molybdenum-based MXene (Mo2C, Mo2N), vanadium-based MXene (V2C, V4C3), and tungsten-based MXene (W 1.3 C), niobium-based MXene (Nb2C, Nb 1.3 A nanocomposite solder characterized by comprising at least one selected from the group consisting of zirconium-based MXene (C, Nb4C3), zirconium-based MXene (Zr3C2), tantalum-based and alloy-based MXene ((Ti,V)2C, (Ti,Nb)2C, (Ti,V)3C2, (Nb,V)4C3, (Ti,Nb)4C3, (Nb,Zr)4C3, (Ti,Nb)4C3).

4. In paragraph 1, A nanocomposite solder characterized in that the diameter of the above two-dimensional nanomaterial is 0.1 μm to 10 μm.

5. In paragraph 1, A nanocomposite solder characterized in that the above two-dimensional nanomaterial is contained in an amount of 0.2 wt% to 10 wt% relative to the total nanocomposite solder content.

6. In paragraph 1, A nanocomposite solder characterized in that the above two-dimensional nanomaterial is dispersed within the tin (Sn)-based solder paste.

7. In the first, A nanocomposite solder characterized in that the grain size of the above nanocomposite solder is 0.1 μm to 100 μm.

8. A step of preparing a first substrate having a nanocomposite solder positioned on the surface and a second substrate spaced apart from the first substrate; and A step of soldering by performing a reflow process by irradiating a laser beam on the nanocomposite solder located in the space between the first substrate and the second substrate, A soldering method using a reflow process characterized by gradually lowering the temperature of a processing area irradiated with the laser beam.

9. In paragraph 8, A soldering method using a reflow process, characterized in that the temperature control method of the above reflow process is performed to cool from a temperature range of 160°C to 140°C to a temperature range of 140°C to 135°C.

10. In paragraph 8, A soldering method using a reflow process, characterized in that cooling is stopped when the grain size of the nanocomposite solder becomes 0.1 μm to 10 μm.

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