Nano-metal composite solder and manufacturing method therefor

Abstract

As for a nano-metal composite solder according to an embodiment of the present invention, a Sn-58Bi alloy powder containing tin was solid-phase mixed with a two-dimensional metal carbide nanosheet powder to prepare a nano-metal composite powder, and a solder powder containing the nano–metal composite powder was thermally treated, followed by manual cold-compressing and a reflow process, to manufacture a Ti3C2Tx-SnBi nano-metal composite solder. By refining the structure of the Sn-58Bi alloy and controlling the generation of intermetallic compounds at the interface, such a nano-metal composite solder exhibits excellent mechanical strength, enhanced thermal and mechanical properties, and improved thermal conductivity, thereby providing the effect of improving heat dissipation characteristics.

Description

Nano metal composite solder and method for manufacturing the same

[0001] The present invention relates to a nano metal composite solder mixed with two-dimensional metal carbide nanosheet powder and a method for manufacturing a nano metal composite solder.

[0002] The present invention relates to a technology for applying a nano-metal composite solder mixed with two-dimensional metal carbide nanosheet powder to the packaging of electronic components requiring high strength and high heat dissipation.

[0003] Solder, which can be joined at low temperatures and is inexpensive and highly reliable, is mainly used to connect electronic components and printed circuit boards used in electronic devices.

[0004] Recently, there has been an increasing trend of electronic products to enhance the convenience and safety of electronic devices and automobiles, and the selection of solder materials is crucial for increasing the reliability of these products.

[0005] Traditionally, Pb-Sn, an alloy of lead and tin, was primarily used as a solder alloy; however, its use has become difficult due to regulations on lead components, which cause environmental pollution when electronic devices using it are discarded.

[0006] Therefore, recently, there has been active development of lead-free solder containing tin (Sn), silver (Ag), copper (Cu), bismuth (Bi), and indium (In) alloy metals without using Pb. However, the high melting point of lead-free solder causes thermal damage to electronic components, and there are problems such as reduced bond strength due to fatigue aging of the solder after cycles and the growth of intermetallic compounds at the interface between the substrate and the solder.

[0007] Recently, to solve this problem, technologies are being developed to add metal elements to lead-free solder or to mix carbon-based nanoparticles into the solder.

[0008] The technical problem to be solved by the present invention is to a nano metal composite solder containing MXene and a method for manufacturing the same.

[0009] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0010] To achieve the above technical problem, one embodiment of the present invention provides a nano metal composite solder.

[0011] According to one embodiment of the present invention, the invention comprises the tin (Sn)-based solder powder; and a two-dimensional metal carbide nanosheet powder; wherein the two-dimensional metal carbide nanosheet powder can be attached to the surface of the tin-based solder powder particles.

[0012] In addition, according to one embodiment of the present invention, the tin (Sn)-based solder powder may include the following chemical formula 1.

[0013] [Chemical Formula 1] Sn-xBi

[0014] In Chemical Formula 1 above, x represents the weight percent of Bi contained in the tin alloy. x is 50 to 60.)

[0015] In addition, according to one embodiment of the present invention, the two-dimensional metal carbide nanosheet powder is a titanium-based MXene Ti3C2Tx, and Tx may include one or more selected from O, OH, F, and Cl.

[0016] In addition, according to one embodiment of the present invention, the two-dimensional metal carbide nanosheet powder may be 0.03 to 0.2 weight% relative to the total nano metal composite solder.

[0017] In addition, according to one embodiment of the present invention, the diameter of the two-dimensional metal carbide nanosheet powder may be 0.1 μm to 10 μm.

[0018] In addition, according to one embodiment of the present invention, the particle size of the tin (Sn)-based solder powder may be 25 μm to 45 μm.

[0019] In addition, the hardness of the nano metal composite solder may be 30 to 44.

[0020] To achieve the above technical problem, another embodiment of the present invention provides a method for manufacturing a nano metal composite solder.

[0021] According to another embodiment of the present invention, a method for manufacturing a nano metal composite solder can be provided, comprising: a first step of mixing tin (Sn)-based solder powder and two-dimensional metal carbide nanosheet powder; and a second step of ball milling the mixed powder.

[0022] According to one embodiment of the present invention, the ball milling may preferably include performing the process using Zr balls for 120 minutes or more and 600 minutes.

[0023] According to one embodiment of the present invention, the method may further include the step of cold-compressing the nano metal composite solder powder to form a nano metal composite solder.

[0024] According to one embodiment of the present invention, the process may further include reflowing the nano metal composite solder at 180°C to 200°C.

[0025] A nano metal composite solder according to one embodiment of the present invention has the effect of attaching powdered two-dimensional metal carbide nanosheets to the surface of a tin-bismuth alloy, thereby refining the structure of the tin-bismuth alloy and controlling the formation of intermetallic compounds at the interface.

[0026] 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 configuration of the invention described in the detailed description of the invention or the claims.

[0027] FIG. 1 is a schematic diagram showing a method for manufacturing a nano metal composite powder according to one embodiment of the present invention.

[0028] Figure 2 is an image showing the ball milling process of one embodiment of the present invention.

[0029] Figure 3 is an SEM image and an EDS analysis image of one embodiment of the present invention.

[0030] Figure 4 is an OM image of one embodiment of the present invention.

[0031] FIG. 5 is a histogram showing the distribution of the layered structure and interlayer spacing of one embodiment of the present invention.

[0032] Figure 6 is an SEM image and IMC thickness data of one embodiment of the present invention.

[0033] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0034] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0035] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0036] Hereinafter, the present invention will be described with reference to the drawings presented in the present invention.

[0037] In the following, unless otherwise noted, units are weight percent.

[0038] A nano metal composite solder according to one embodiment of the present invention is described.

[0039] A nano metal composite solder according to one embodiment of the present invention comprises tin (Sn)-based solder powder; and two-dimensional metal carbide nanosheet powder, wherein the two-dimensional metal carbide nanosheet powder may be attached to the surface of the tin (Sn)-based solder powder.

[0040] First, the present invention may include tin (Sn)-based solder powder.

[0041] At this time, the tin (Sn)-based solder powder used in the present invention may include the following chemical formula 1.

[0042] [Chemical Formula 1] Sn-xBi

[0043] (In Chemical Formula 1 above, x represents the weight percentage of Bi contained in the tin alloy. x is 50 to 60.)

[0044] At this time, the present invention is not limited to the type of powder described above, but may also be applicable to other types of powder.

[0045] For example, the powder composition may further include metals such as Ni, Au, Pd, Pt, Fe, Co, and Cu.

[0046] Next, the present invention may include two-dimensional metal carbide nanosheet powder.

[0047] At this time, the two-dimensional metal carbide nanosheet powder material used in the present invention is titanium-based MXene Ti3C2Tx, and Tx may include one or more selected from O, OH, F, and Cl.

[0048] The general chemical formula of MXene is M (n+1) X n It is represented as Tx(n=1, 2, 3), where X represents a carbon or nitrogen layer. This X layer is covered from above and below by a transition metal layer (M), and this metal layer (M) combines with O, OH, F, Cl, etc. to form surface functional groups (Tx).

[0049] To date, more than 100 types of compositions and solid solutions have been studied, which possess high electrical conductivity, thermal conductivity, and hydrophilicity, which are characteristics of MXene, through various combinations of M and X layers.

[0050] The diameter of the two-dimensional metal carbide nanosheet powder used in the present invention may be 0.1 μm to 10 μm.

[0051] At this time, the reason the diameter of the two-dimensional metal carbide nanosheet powder is 0.1 μm to 10 μm is that if the diameter is less than 0.1 μm, there may be a problem with the nanomaterial particles aggregating, and if it exceeds 10 μm, there may be a problem with the nanomaterial particles being difficult to disperse within the nanocomposite solder.

[0052] At this time, the two-dimensional metal carbide nanosheet powder may be included in an amount of 0.03 to 0.2 weight percent relative to the total solder content of the nano metal composite.

[0053] The reason the content of the above two-dimensional metal carbide nanosheet powder is 0.03 to 0.2 weight% is that if it is less than 0.03 weight%, there may be a problem in that the mechanical strength and heat dissipation characteristics of the nanocomposite solder are not improved by the nanomaterial particles, and if it exceeds 0.2 weight%, there may be a problem in that the nanomaterial particles aggregate within the nanometalcomposite solder and it is difficult to form solder balls.

[0054] The size of the above tin (Sn)-based solder powder particles may be 25 μm to 45 μm.

[0055] The hardness of the above nano metal composite solder may be 30 to 44.

[0056] In this case, the nano metal composite solder has the effect of improving mechanical properties and thermal conductivity by trapping the material on the surface of the nano metal composite solder within tin-containing powder, thereby enhancing hardness through a reduction in the solder's grain size and improving heat dissipation characteristics.

[0057] In addition, the Ti3C2Tx-SnBi metal nanocomposite solder of the present invention has a finer Sn and Bi structure compared to SnBi alloy, and as a result, the Ti3C2Tx-SnBi metal nanocomposite solder exhibits higher hardness.

[0058] As a result of measuring the hardness of the Ti3C2Tx-SnBi composite, the Ti3C2Tx content was of the total weight The highest hardness value is shown in the case of approximately 0.13 weight%.

[0059] Specific process conditions regarding this will be explained in the following nanocomposite solder manufacturing method.

[0060] Hereinafter, a method for manufacturing a nano metal composite solder according to another embodiment of the present invention will be described.

[0061] A method for manufacturing a nano metal composite solder according to one embodiment of the present invention refers to FIGS. 1 and FIGS. 2.

[0062] According to FIG. 1, the two-dimensional metal carbide nanosheet powder of the present invention is characterized by being attached to the surface of the tin (Sn)-based solder powder.

[0063] According to FIG. 2, the method may include: a first step of mixing tin (Sn)-based solder powder and two-dimensional metal carbide nanosheet powder; and a second step of ball milling the mixed powder.

[0064] At this time, the method is characterized by placing zr balls into a ball mill, adding tin (Sn)-based solder powder and two-dimensional metal carbide nanosheet powder, and then mixing at an idle speed of 150 rpm for 120 minutes to 600 minutes.

[0065] At this time, the tin (Sn)-based solder powder used in the present invention may include the following chemical formula 1.

[0066] [Chemical Formula 1] Sn-xBi

[0067] (In Chemical Formula 1 above, x represents the weight percentage of Bi contained in the tin alloy. x is 50 to 60.)

[0068] At this time, other types of powder may be included.

[0069] For example, the powder composition may further include metals such as Ni, Au, Pd, Pt, Fe, Co, and Cu.

[0070] At this time, in the present invention, the two-dimensional metal carbide nanosheet powder is titanium-based MXene Ti3C2Tx, and Tx may include one or more selected from O, OH, F, and Cl.

[0071] The above two-dimensional metal carbide nanosheet powder may be included in an amount of 0.03 to 2 weight percent relative to the total mixture content.

[0072] The diameter of the above two-dimensional metal carbide nanosheet powder may range from 0.1 μm to 10 μm.

[0073] The size of the tin (Sn)-based solder powder particles may range from 25 μm to 45 μm.

[0074] At this time, the grain size of the tin (Sn)-based solder powder and the two-dimensional metal carbide nanosheet powder can be reduced to suppress the growth of the IMC (Intermetallic Compound) and to limit the particle size to improve hardness.

[0075] In addition, IMC growth refers to the thickening of intermetallic compounds due to external stress such as thermal shock. Although IMC growth is formed at a thickness of about 1 to 5 µm at the beginning of bonding, if the thickness exceeds 7 µm, it causes problems with bonding strength.

[0076] The above ball milling can be performed using Zr balls for 120 minutes to 600 minutes.

[0077] At this time, the size of the Zr balls is 3 mm or less, and if the ball milling time is 120 minutes or less, the particle size is large and molding is difficult, and if it is 600 minutes or more, the particles become fine and may re-aggregate, so the time is adjusted to 120 minutes to 600 minutes.

[0078] The method may further include a step of forming a metal composite by pressing the above-mentioned nano metal composite solder powder. The method for manufacturing the metal composite involves heat treating at 180°C and forming by manual, cold compression pressing.

[0079] The process may further include reflowing the above nano metal composite solder at 180°C to 200°C.

[0080] At this time, the reflow process is a process of manufacturing a circuit board by applying heat through a soldering device to melt the nano metal composite solder and then solidifying it again. If the reflow temperature is high, the substrate and semiconductor package other than the solder may be heated, which can cause problems such as device damage or warpage of the component.

[0081] The present invention will be explained in more detail below through manufacturing examples and experimental examples. These comparative examples, manufacturing examples, and experimental examples are solely for the purpose of illustrating the present invention, and the scope of the present invention is not limited by these comparative examples, manufacturing examples, and experimental examples.

[0082] (Example 1) Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.03 wt%)

[0083] Nano metal composite solder powder was prepared with reference to Fig. 1.

[0084] First, 50g of Sn-58Bi powder with a particle size of 25–45um was mixed with powdered MXene Ti3C2Tx content (0.03 wt%, 0.015g), and then ball-milled using Zr balls to prepare a Ti3C2Tx / Sn-58Bi mixture.

[0085] (Example 2) Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.07 wt%)

[0086] The procedure was carried out in the same manner as Example 1, except that a Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.07 wt%, 0.0375 g) was used.

[0087] (Example 3) Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.1 wt%)

[0088] The procedure was carried out in the same manner as Example 1, except that a Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.1 wt%, 0.05 g) was used.

[0089] (Example 4) Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.13 wt%)

[0090] The procedure was carried out in the same manner as Example 1, except that a Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.13 wt%, 0.065 g) was used.

[0091] (Example 5) Ti3C2Tx / Sn-58Bi composite Ti3C2T x content (0.17 wt%)

[0092] Ti3C2Tx The procedure was carried out in the same manner as Example 1, except that Sn-58Bi composite Ti3C2Tx content (0.17 wt%, 0.085 g) was used.

[0093] (Example 6) Ti3C2Tx / Sn-58Bi composite Ti3C2Tx content (0.2 wt%)

[0094] Ti3C2Tx The procedure was carried out in the same manner as Example 1, except that Sn-58Bi composite Ti3C2Tx content (0.2 wt%, 0.1 g) was used.

[0095] (Comparative Example 1) Sn-58Bi powder

[0096] In Comparative Example 1, 50g of commercial Sn-58Bi powder was used.

[0097] Experimental Example 1: Verification Experiment of Nano Metal Composite Solder Manufacturing

[0098] In Experimental Example 1, the preparation of a nano metal composite solder is confirmed with reference to Fig. 3.

[0099] The SEM image in Fig. 3 shows the surface morphology and compositional distribution of the Ti3C2Tx-SnBi composite powder produced by the ball milling method.

[0100] Figure 3 (a) shows the surface morphology of Sn-58Bi particles without Ti3C2Tx, and (b) shows the surface morphology of the Ti3C2Tx-SnBi composite powder; as seen in (b), Ti3C2Tx nanosheets attached to the surface of the Sn-58Bi particles were observed.

[0101] Figures 3(c) to 3(f) show the results of EDS analysis of the Ti3C2Tx-SnBi composite powder, and the presence of Ti elements was observed, confirming the existence of Ti3C2Tx on the surface.

[0102] Experimental Example 2: Experiment to Verify Nano-Metal Composite Solder Properties

[0103] In Experimental Example 2, the characteristics of the nano metal composite solder are confirmed with reference to Fig. 4.

[0104] Figure 4 shows the microstructural changes resulting from the addition of two-dimensional metal carbide nanosheets through SEM / EDX analysis of the nano metal composite solder, and Vickers hardness was evaluated to assess changes in mechanical properties.

[0105] Fig. 4 shows (a) Sn-58Bi powder and (b) Ti3C2T, respectively. x - The microstructure of a sample sintered with SnBi composite powder at 180°C for 70 minutes and (c) the experimental result of measuring the hardness of the sample using a micro-Vicker.

[0106] (c) Ti3C2T in Fig. 4 x Ti3C2T according to composition x - As a result of measuring the hardness of the SnBi composite, Ti3C2T x The hardness of SnBi not containing this was 33.33 HV, and Ti3C2T x 0.13 wt% of Ti3C2T x It exhibited the highest hardness of 43.73 HV among SnBi composites.

[0107] This is Ti3C2T as seen in Figures 4 (a) and (b).x - SnBi composites have finer Sn and Bi structures compared to SnBi alloys, and as a result, Ti3C2T x It was found that the SnBi composite has higher hardness.

[0108] Figure 5 shows Ti3C2T x (a)–(g) Ti3C2T in the eutectic lamellae structure shown by the SnBi complex x This is a histogram showing the distribution of interlayer spacing (or grain size) of Sn and Bi layered structures according to their composition.

[0109] Also, (f) of Fig. 5 is Ti3C2T x It shows that the average interlayer spacing changes according to the composition, and at a content of 0.07 wt.%, the interlayer spacing rapidly became finer, and thereafter showed a tendency to gradually decrease as the content increased.

[0110] Experimental Example 3: Experiment to Verify Nano-Metal Composite Solder Properties

[0111] In Experimental Example 3, the characteristics of the nano metal composite solder are confirmed with reference to Fig. 6.

[0112] Figure 6 shows the microstructure of solder balls fabricated using solder paste containing Ti3C2Tx-SnBi composite powders with various compositions, and the change in thickness of intermetallic compounds was confirmed through optical microscopy and SEM analysis. As shown in Figure 6, as the content of Ti3C2Tx increases, the microstructure of the SnBi alloy becomes finer, and the thickness of the intermetallic compounds formed at the interface with the ENIG substrate decreases, changing from a scallop shape to a thin filament shape.

[0113] As described above, the present invention has been explained by specific details and limited embodiments; however, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0114] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

1. Tin (Sn)-based solder powder; and Includes two-dimensional metal carbide nanosheet powder; and A nano metal composite solder characterized by the above two-dimensional metal carbide nanosheet powder being attached to the surface of the above tin-based solder powder particles.

2. In Paragraph 1, The above tin (Sn)-based solder powder is a nano metal composite solder characterized by comprising the following chemical formula 1. [Chemical Formula 1] Sn-xBi (In Chemical Formula 1 above, x represents the weight percentage of Bi contained in the tin alloy. x is 50 to 60.) 3. In Paragraph 1, The above-described two-dimensional metal carbide nanosheet powder is titanium-based MXene Ti3C2Tx, and the nano metal composite solder is characterized in that Tx includes one or more selected from O, OH, F, and Cl.

4. In Paragraph 1, The above-described two-dimensional metal carbide nanosheet powder is titanium-based MXene Ti3C2Tx, and the nano metal composite solder is characterized in that Tx includes one or more selected from O, OH, F, and Cl.

5. In Paragraph 1, Na, characterized in that the diameter of the above-mentioned two-dimensional metal carbide nanosheet powder is 0.1 μm to 10 μm. No metal composite solder.

6. In Paragraph 1, A nano metal composite solder characterized in that the size of the tin (Sn)-based solder powder particles is 25 μm to 45 μm.

7. In Paragraph 1, A nano metal composite solder characterized by having a hardness of 30 to 44.

8. Step 1 of mixing tin (Sn)-based solder powder and two-dimensional metal carbide nanosheet powder; A method for manufacturing a nano metal composite solder, characterized by performing a process including the second step of ball milling the above-mentioned mixed powder.

9. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized in that the tin (Sn)-based solder powder comprises the following chemical formula 1. [Chemical Formula 1] Sn-xBi (In Chemical Formula 1 above, x represents the weight percentage of Bi contained in the tin alloy. x is 50 to 60.) 10. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized in that the above-described two-dimensional metal carbide nanosheet powder is titanium-based MXene Ti3C2Tx, and Tx comprises one or more selected from O, OH, F, and Cl.

11. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized in that the above-described two-dimensional metal carbide nanosheet powder is 0.03 to 0.2 weight% relative to the total nano metal composite solder.

12. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized in that the diameter of the above two-dimensional metal carbide nanosheet powder is 0.1 μm to 10 μm.

13. In Paragraph 8, A method for manufacturing a nano metal composite solder characterized in that the size of the tin (Sn)-based solder powder particles is 25 μm to 45 μm.

14. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized by performing the ball milling using Zr balls for 120 minutes to 600 minutes.

15. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized by further including the step of heat-treating the above nano metal composite solder powder at 180°C and manually cold-compressing it to form a nano metal composite solder.

16. In Paragraph 8, A method for manufacturing a nano metal composite solder, characterized by further including a process of reflowing the above nano metal composite solder at 180°C to 200°C.

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