TWI360452B - Composite lead-free solder composition having nano - Google Patents

Description

1360452 Replacement page on November 16, 100. Description of the Invention: [Technical Field of the Invention] The present invention relates to a composite lead-free solder composition, in particular, a method for inhibiting the formation of a metal-containing compound of a tin-silver-copper alloy. Nano composite lead-free solder composition. [Prior Art] In current electronic products, tin-lead alloys are often used as solders for bonding small electronic components. However, due to the toxic pollution of lead and its compounds to the environment, international regulations have gradually limited the use of miserable solders in electronic products. For example, the “Waste Electrical and Electronic Equipment 'WEEE” rule sets forth standards for the collection and recycling of electronic products, and the “restriction of hazardous substances (RoHS) regulations are an attempt Reducing the use of these electronic products in the use, processing and exposure of the above-mentioned regulations, many of the electronics OEMs began to transform the assembly of products sold in Europe and Japan into error-free processes, especially the major semiconductor packages廒Commercial and passive component suppliers are following this trend to introduce a variety of error-free packaged products and error-free passive components. Currently, in the production cost control and technical reliability, the use of lead-free tan products has matured, of which common lead-free solder According to the melting point of lead-containing solder Sn37Pb (containing 37% lead, melting point 183 ° C), it is divided into: low melting point solder, such as Sn58Bi (containing 58% of bismuth, melting point 138C), In3Ag (containing 97% of indium and 3% silver, melting point 143 ° C), 1360452 100 November 100 replacement page

Sn52In (containing 52% of the face 'melting point 118. 〇; approximate Sn37Pb eutectic spot solder, such as Sn0.7Cu (containing 0.7% copper, melting point 227. 〇), Sn3.5Ag (containing 3.5% copper, Hyun point 221 〇 C), Sn9Zn (containing 9% zinc, melting point 199 ° C), Sn3.5AgO.7Cu (including 3.5% silver and 0.7%

Copper 'refining point 221 ° C); and, high-point solder has Au20Sn (80% gold and 20% tin, melting point 282. 〇, Sn5Sb (including 5% 绨, melting point 233-240 ° C), etc. Table 1 below is a material analysis of commonly used error-free solders. Under the test point and cost, tin-silver alloys such as Sn0.7Cu and Sn3.5Ag have better competitive advantages. However, on the other hand, tin-silver alloys. However, it also has problems such as poor mechanical properties and low welding reliability.

Table 1. Material characteristics of commonly used lead-free solders. Solder Sn37Pb Sn3.5Ag Sn0.7Cu Sn3.5Ag0.7 Cu Au2〇Sn Melting point (°c) 183 221 227 217 280 Specific gravity (g/cm3) 8.4 7.5 7.3 7.5 14.51 Resistance value (μΩ«η) 15 10.8 10-15 13 17.9 Thermal conductivity (W/cm.°C) 0.5 (85°〇0.33 (85°〇—0.35 (85〇C) 57 Thermal expansion coefficient CTE (ppm/K) 25 30 25 17 16 Tensile strength (Mpa) 46 35 23 48.5 36 Shear strength (Mpa) 23 27 20-23 — A Young's modulus (GPa) 30 16.5 12.8 — 60 ductility (%) 31 39 45 36.5

On November 16th, 100th, the replacement of the electronic products with the development of electronic products has become smaller, more versatile, high-frequency and high-density density. Some electronic components have been created, for example: ball grid package (ball grid Array, BGA), flip chip assembly (FCA), multi-chip module (MCM), chip scaie package (CSP), wafer level package (WLP level package) )Wait. As the number of input/output terminals I/0 (Input/0utput) of the package structure continues to increase and the diameter of the flip-chip bump continues to decrease, as shown in Fig. 1, the diameter is 20 μm (micrometer). Tin-silver (SnAg) alloy flip-chip bumps, which can be used to connect between a chip and a substrate to form a flip-chip solder joint. The current density of the flip chip is generally increased as the size is reduced, so that the current density through the solder joint may be as high as 1 安 4 amps/cm 2 (A/cm 2 ) or more. At such high current densities through the flip chip, the amount of heat generated by the current will increase at a very high rate. Many studies have pointed out that at least two or more embrittlement modes of the joint between the lead-free solder and the copper pad are caused by the damage caused at the interface, and the main factor of failure is mechanical shock or It is the thermal stress caused by the difference in thermal expansion coefficient (CTE) of the material, which will cause the interfacial layer to form an intermetallic compound (IMC) and become the starting point of the failure; of course. The origin of the breakdown of mechanical shock also occurs at the interface. As described above, when solder soldering is bonded to an electronic component, the solder may have to undergo thermal stress alone during the long-term high-temperature use of the replacement page on November 16, 100, which causes the solder to creep. This phenomenon will cause the electronic signal to be not correctly transmitted. For example, in the field of semiconductor packaging, when a tin-silver alloy solder (such as Sn3.5Ag), a tin-copper alloy solder (such as Sn0.7Cu) or a gold-tin alloy solder (such as Au20Sn) is used as a bump to media bond wafer pads When the substrate pad is used, a metal-containing compound layer (for example, Ag3Sn, Cu3Sn, AuSn, etc.) is easily generated, which causes a creep in the temperature cycle test to be incapable of withstanding thermal stress caused by the thermal stress. Or can not withstand the load caused by external mechanical stress. Therefore, the hard and brittle intermetallic compound layer tends to become the starting point at which cracking occurs, thus causing failure of the solder joint. In order to prevent this problem from happening, the solder joint must have a stable microstructure and excellent creep resistance, and it is necessary to avoid the formation of a brittle predile compound after welding to prevent it from becoming a source of damage. The packaging industry hopes to develop new alloys to replace the known shipless solder alloys described above to provide excellent creep impedance in extreme temperature environments. Therefore, it is necessary to provide a lead-free solder composition to solve the problems of the prior art. SUMMARY OF THE INVENTION The main object of the present invention is to provide a nano-composite lead-free solder composition which is further provided with nano-particles in a lead-free solder based on a tin-silver-copper alloy to utilize the characteristics of the nano-particles. Refining the structure of tin-silver-copper alloy, suppressing the coarsening of the tin-silver-copper alloy. 1360452 Replacement of the complexes on November 16th, in order to increase the mechanical strength and inhibit the growth of the intermetallic metal after welding' and slow down the intermetallic Increased thickness, which in turn enhances the soldering of the electronic product and its service life. A secondary object of the present invention is to provide a nano-composite lead-free solder composition, which is selected by using a rolling kneading method or a magnetic stirring method to uniformly mix nano particles in a tin-silver-copper alloy to smoothly manufacture a nanometer. Composite lead-free solder, which is beneficial to improve the quality of solder blending and reduce manufacturing costs. To achieve the above object, the present invention provides a nanocomposite lead-free solder composition comprising: 0.01 to 5.0% by weight of silver (Ag), 0.01 to 3.0% by weight of copper (Cu), and 0.25 to 2.0% by weight The nano particles and the rest are tin (Sn) ' wherein the nano particles are selected from the group consisting of titanium dioxide (Dings 2), aluminum oxide (Αία;), zinc peroxide (Ζη02), zirconium dioxide (zr〇2) And a carbon nanotube (CNT) or a mixture thereof, and the nanoparticle has a particle size of between 5 and 500 nanometers (nm). In one embodiment of the invention, the nanocomposite lead-free solder composition is composed of a tin-silver-copper alloy (Sn-Ag_Cu alloy) mixed with the nanoparticle. In one embodiment of the invention, the nanoparticles are mixed into a tin-silver-copper alloy by a rolling kneading process. In one embodiment of the invention, the nanoparticles are uniformly dispersed between a plurality of layers of tin-silver-copper alloy sheets of the error-free solder laminate. In one embodiment of the invention, the nanoparticles are de-mixed into the tin-silver-copper alloy using magnetic agitation. 8100 November 16 曰 Replacement page In one embodiment of the invention, the silver content is selected from the group consisting of 2.5% by weight, reset/°, 3.5% by weight, 38% by weight, and 39% by weight. % by weight, 4.5% by weight or 5. % by weight. Re-emphasis in the invention - copper. ·6 heavy ~ discussion, 0. coffee or. Chuanzhong implements the wealth, and the content of the naphthene is selected from η 〇. 5 wt%, L 〇 wt% or 1.5 wt%. Titanium, 1 is invented - in the embodiment, the nanoparticle is selected from the group consisting of dioxins, and the particles 2 to 3 are oxidized. The nanoparticles are selected from the group consisting of trioxide II. The peroxidized nanoparticle is selected from the group consisting of aluminum in an embodiment of the invention having a particle size of 30 to 40 nm. In one embodiment of the invention, the particle size is 35 to 45 nm. In one embodiment of the invention, zirconium having a particle size of from 20 to 30 nm is prudent in one of the inventions: a point of gentleman's tube having a particle size of from 2 Å to (10) nm. The nanoparticle is selected from the group consisting of Naicai carbon (Ce) in the embodiment of the invention. 〇.〇〗 to 55 weight 〇/0 In the present invention - another embodiment (Bi). 〇·〇] to 0.5% by weight

f. The purpose, features, and advantages of the present invention can be made apparent by the above-described and other alternative pages of the present invention on November 16th, and the preferred embodiments of the present invention will be described hereinafter. The details are as follows. In a preferred embodiment of the present invention, the present invention provides a nanocomposite lead-free solder composition for applying soldering electronic components combined with various electronic products, for example, in the field of semiconductor packaging, as a bump. Solder for solder bonding of wafer pads and substrate pads; or as solder ball solder on the lower surface pads of the substrate. In addition, the nano-composite lead-free solder composition of the present invention may also be applied to an electrode pre-solder as a passive component; or as a solder for surface mount technology (SMT) of an electronic component. In order to solder the electronic components to the circuit board (such as the motherboard or mobile phone board). However, the above is merely illustrative of possible fields of application of the nano-composite error-free solder composition of the present invention, but is not intended to limit the present invention. In a preferred embodiment of the present invention, the nanocomposite lead-free tin-forming composition of the present invention is mainly composed of a tin-silver-copper alloy (Sn-Ag-Cu alloy) mixed with nanoparticles, wherein the tin-silver-copper alloy It may be selected from various ratios of tin-silver-copper alloys, but generally comprises: O.Oi to 5 〇% by weight of silver (Ag) and 〇.〇1 to 3. 〇% by weight of copper (Cu), the nai The proportion of the rice particles blended into the tin-silver-copper alloy is 0.25 to 2.0% by weight, and the remainder is supplemented with tin (Sn) to 1% by weight. If necessary, the present invention may further comprise: 0.01 to 0.5% by weight of cerium (Ce) (for example, adding 0.25 % by weight) to slow the coarsening of the Ag3Sn particles and suppress the problem of the strength drop of the aging push test; or may also include 0.01 to 0.5% by weight of bismuth (Bi) (for example, adding 1360452 100 牟November 16, replacement page 5·5 wt%) to reduce the melting point of the nanocomposite lead-free solder. In a preferred embodiment of the invention, the nanoparticle means a group of specific substances pre-ground to have a nanometer-sized particle size, preferably selected from the group consisting of titanium dioxide (Ti〇2) and aluminum oxide (Al2〇3). ), zinc peroxide (Zn〇2), a zirconium oxide (Zr〇2), a carbon nanotube (CNT) or a mixture thereof. Meanwhile, in the present invention, the particle size of the nanoparticle The system is controlled between 5 and 500 nanometers (nm).

In a preferred embodiment of the invention, the silver content of the nanocomposite lead-free solder composition is controlled to be between 0.01 and 5.0% by weight, preferably between 2.5 and 5.0% by weight, especially 2.5 parts by weight. %, 3.0% by weight, 3.5% by weight, 3.8% by weight, 3.9% by weight, 4.0% by weight, 4.5% by weight or 5.0% by weight. Furthermore, the copper content is controlled between 0.01 and 3.0% by weight, preferably between 〇.2 and 1.0% by weight, in particular 0.5% by weight, 0.6% by weight, 0.7% by weight, 0.8% by weight or 0.9. weight%. In one embodiment, the tin-silver-copper alloy substrate of the present invention is preferably selected from one of the following composition ratios (all in weight percent): tin - 2.5% silver - 0.8 〇 / 〇 copper (ie 8112.5 eight 0.8 (:11), tin-3.0% silver-0.5% copper (ie 8113.0 into 0.5(:11), tin-3.5% silver-0.5〇/〇 copper (ie 8113.5 into 8〇.5(:11), tin -3.5% silver-0.9% copper (ie 8113.5 八吕 0.9〇1), tin-3.8 〇/〇 silver-0.5〇/〇 copper (ie 8113.8 into §0.5 (:11), tin 3.8% silver-0.7〇/ Beryllium copper (ie Sn3.8AgO.7Cu), tin-3.9°/. silver-0.6% copper (ie Sn3.9AgO.6Cu), or tin-4.0% silver-0.5% copper (ie Sn4.0Ag0.5Cu), In particular, it is selected from the group consisting of tin-3.5% silver-〇.5°/. copper (ie, Sn3.5AgO.5Cu), but is not limited thereto. 11 1360452 November 16, 2010 Replacement Page In the preferred embodiment of the present invention The nanoparticle in the nano composite lead-free solder composition may be selected from the group consisting of titanium dioxide, aluminum oxide, peroxide, zirconium dioxide, carbon nanotubes or a mixture thereof, and the nano particles are mixed into The ratio in the tin-silver-copper alloy is controlled to be between 0.25 and 2.0% by weight, preferably between 0.25 and 1.8% by weight. Between 0.25 and 1.5% by weight, the particle size of the nanoparticle is controlled between 5 and 500 nanometers (nm), preferably between 20 and 100 nanometers, especially Between 20 and 50 nm. In one embodiment, the nanoparticulate is selected from the group consisting of titanium dioxide having a particle size of 20 to 30 nm (e.g., 25 nm or 30 nm), and a blending ratio thereof. The control is 0.25 to 1.5% by weight. In another embodiment, the nanoparticle is selected from the group consisting of aluminum oxide, having a particle size of 30 to 40 nm (for example, 35 nm), and the mixing ratio thereof is controlled. It is 0.25 to 1.5% by weight. In still another embodiment, the nanoparticle is selected from the group consisting of zinc peroxide having a particle size of 35 to 45 nm (for example, 40 nm), and the mixing ratio thereof is controlled to 0.25. In another embodiment, the nanoparticle is selected from the group consisting of zirconium dioxide, having a particle size of 20 to 30 nm (for example, 20 nm), and the mixing ratio thereof is controlled to 0.25 to 1.5. In still another embodiment, the nanoparticle is selected from the group consisting of a carbon nanotube having a particle diameter (tube diameter) of 20 to 100 nm (for example, 25 nm) and a length of 100 to 3000 nm, and the blending ratio thereof is controlled to be 0.25 to 1.5% by weight. Referring to Figures 2A to 2E and 3A to 3B, the nano composite lead-free solder composition of the preferred embodiment of the present invention is mainly The tin-silver-copper alloy is mixed with the nanometer particles, and the preferred method is to use the rolling mixed 12 1360452 2 method or the magnetic mixing method to apply the nano-fine teaching to the alloy, and the process steps of the two will be Referring to Figures 2A to 2E, in the example of the present invention, the present invention chooses to use the hybrid compounding method - the first implementation of the tin-silver-copper alloy sheet u: first prepare a plurality of

Rice microparticles] 2 (4) When 様 (4) and the tin-silver-copper alloy sheet, and 51 UX) are coated on the body η stacked into a lead-free bismuth-doped laminate.接接: Silver-copper alloy sheet Rolling the error-free solder stack 4 to make it extend and use - roller 2: After the first-time spin-drying, the lead-free 对 times are folded in half. Subsequently, the two rollers are used to stretch again to increase the length and reduce the thickness. = two people

In November, 100, the replacement page of L-------- is mixed in tin-silver-copper. The following is a detailed description of the process of continuation = 峨 and half-fold until the thickness of the tin-silver-copper sheet Decrease to - predetermined value. Thus, a nano-composite tin-free 1G can be obtained, and the nano-particles 12 can be substantially spread over hundreds or thousands of layers of the tin-silver-copper alloy sheet u. After the above steps of the rolling and mixing method, the nano composite composite can be directly used for various welding purposes, and can be made into (10), rod or strip (10); or, Reflowing or remelting is performed to remelt into the lead-free solder composition of the present invention, at which time the substrate of the tin-silver-copper alloy has no layered structure, and the nano The particles 12 can be substantially uniformly dispersed in the substrate of the tin-silver-copper alloy (not shown). In the present process, the composition ratio of the silver and copper of the present invention on November 16, 100, and the composition of the nanoparticles must be controlled within the composition ratio range mentioned above in the present invention. Referring to Figures 3A through 3B, in a second embodiment of the present invention, the present invention selectively employs a magnetic stirring method in which a tin-silver-copper alloy 31 and at least one nanoparticle 32 are first prepared. Next, a container 4 is prepared and a magnetic stirrer 5 is placed in advance, and the tin-silver-copper alloy 31 and the nanoparticle 32 are poured into the container 4. Subsequently, the container 4 is heated by a heating type electromagnetic stirrer 6 to melt the tin-silver-copper alloy 31, and the magnetic stirrer 5 is rotated by the magnetic turntable (not shown) inside the heated electromagnetic stirrer 6. The tin-silver-copper alloy 31 and the nano-particles 32 are uniformly mixed. In the present invention, the nanoparticle 32 may be added to the container 4 at the beginning, or may be slowly added thereto after the tin-silver-copper alloy 31 is melted. Further, the tin-silver-copper alloy 31 may be directly selected from the alloy powder of tin-silver-copper or may be selected from a composite powder in which individual metal powders of tin, silver and copper are mixed in proportion. After stirring for a predetermined period of time, the molten metal is poured out to be cooled and solidified into a nanometer-composite lead-free solder 30, so that the nanoparticle 32 can be substantially uniformly dispersed in the tin-silver-copper alloy 31. In the present process, the composition ratio of silver, copper and nanoparticles must be controlled within the composition ratio range mentioned above in the present invention. After the nano-composite lead-free solder composition is prepared by the rolling kneading method or the magnetic mixing method, the nano-particles are evenly dispersed in the tin-silver-copper alloy, and the nano-particles can withstand more than 300 degrees. The high temperature, so it has the excellent characteristics of not participating in the splicing melting reaction, not gathering coarsening and there will be no diffusion 14 1360452 __ 100 November replacement page phenomenon. Thus, for example, in one embodiment, when the nanocomposite lead-free solder composition of the present invention is applied to the field of semiconductor package t as a bump material, it can be reflowed first (refl0W; • is bonded to the aluminum pad or copper pad (not shown) of the wafer, and then soldered to the copper pad (not shown) of the substrate to be between the aluminum pad or the copper pad of the wafer and the copper pad of the substrate. A bump welded structure is formed. In the bump soldering structure, the nanoparticle can effectively inhibit the formation of an intermetallic compound (IMC) layer between the tin-silver-copper alloy and the copper pad, and the intermetallic compound layer is reduced to less significant. degree. Furthermore, even if the nano-composite layer in the vicinity of the intermetallic compound layer is formed in the solder joint of the nano-composite lead-free solder, the nano-particles can be used as barrier particles to effectively suppress the copper at the intermetallic compound layer. It diffuses into the tin-silver-copper alloy through the intermetallic compound layer. More specifically, suppressing the diffusion of copper can avoid the formation of a kekendo micropore in the intermetallic compound layer (Kirkenda11 ν. ♦ thus effectively reducing the intermetallic metal layer due to micropores) Structural embrittlement and cracking risk 0 In addition, the present invention is based on the tin-alloy base (four) mixed with the nano-micromixed (four) mechanical strength system is significantly better than the pure copper alloy machine = strength, but its ductility will The principle of improving the mechanical strength of the present invention is the precipitation strengthening mechanism of the alloy material. Therefore, based on the above principle, the nanoparticle of the present invention can effectively refine the tin-silver-copper alloy structure and suppress the tin-silver. The steel alloy produces a coarsened intermetallic compound to increase its mechanical strength, and inhibits the growth of the post-weld intermetallic metal, and slows the increase in the thickness of the intermetallic metal to prevent the formation of tin-silver-copper alloy. The solder joints crack the surface under temperature cycling test or external mechanical shock, thereby improving the reliability of the electronic product and its service life. In a preferred embodiment of the invention, the present invention has a composition of 0.25 wt%, φ OJ wt%, and I.0, respectively, based on tin-silver-copper. (Sn3.5Ag〇.5Cu) lead-free solder. % by weight of titanium dioxide nanoparticle (particle size 30 nits) 'to test the solidus temperature, liquidus temperature and melting range using a thermal difference analyzer (DSC) And the mechanical properties analysis, the analysis results are shown in Table 2 and Table 3 below: Table 2, the nano composite lead-free solder composition of the present invention and the general tin-silver-copper (SAC) lead-free solder using a thermal difference analyzer to test the solid phase Wire temperature (Ts), liquidus temperature (T!) and melting point range (eight D data, solder nano-Ti02 Ts T, ΔT (% by weight) CC) ΓΟ (°C) Conventional SAC — 220.1 223.6 3.5 The present invention SAC-0.25TiO2 0.25 220.5 224.8 4.3 The present invention SAC-0.5TiO2 0.5 220.6 225.7 5.1 The present invention SAC-1.0TiO2 1.0 220.9 226.8 5.9 Table 3, the present invention nano-composite error-free solder composition and general tin silver copper jSAC) Analysis of mechanical properties of lead-free solder_ solder nano microhardness tensile strength 0.2 fluctuating ductility 16 , 452 100 November 16 replacement page

Ti02 (% by weight) (Hv) (MPa) Strength (MPa) (Pet) Conventional SAC — 15.2 55.7 53.2 48.6 The present invention SAC-0.25TiO2 0.25 17.1 61.5 59.5 40.5 The present invention SAC-0.5TiO2 0.5 17.5 69.1 67.6 32.1 The SAC of the present invention -1.0TiO2 1.0 18.5 70.1 69.3 25.2

Please refer to Figures 4A and 4B, which are electronic displays of the alloy microstructure of a general tin-silver-copper (Sn3.5AgO.5Cu) lead-free solder alloy and its reflow soldering (refl〇w) bonded to the copper pad of the wafer. The micrograph shows that the base of the tin-silver-copper alloy has a gray-white coarse needle-like Ag3Sn and a gray-black needle-like Cu^Sn5 intermetallic compound. Referring to Figures 5A, 5B, 5C, and 6, the present invention adds 〇·25 wt%, 0.5 wt%, and 1 wt% of tin-silver steel (sn3 5Ag〇.5Cu) error-free solder, respectively. Nano-composite lead-free solder joint prepared by titanium dioxide nano particles

An electron micrograph of the microstructure of the alloy and its reflow solder bonded to the copper pad of the wafer, which shows that no coarse intermetallic compound is present in the substrate of the tin-silver-copper alloy, wherein the interfacial layer only forms a CU6Sn5 intermetallic compound, ChSn media, metal compounds were not produced. In addition, in the solder position, no plate-shaped human heart and other metal compounds such as CU6%5 are formed, and the addition of dioxetane can effectively fine-tune the microstructure and inhibit; the formation and formation of metal compounds and slow down Kekendo The creation of a Kirkendall void. Please refer to Figure 7 for the mechanical properties analysis of different amounts of dioxin (10) rice particles added to the nano-composite error-free solder of the invention. It can be seen that the invention is in Xi 2 17 1360452 1 November 2005 On the daily replacement page, the copper (SnDAgG.Wu) material-free substrate, %, 〇·5% by weight, and Μ% by weight of the titanium dioxide nanoparticles (10)·strain (%) behaved better than pure tin-silver; Sn^5Ag0.5CU) is a solder-free solder, and the higher the content of titanium dioxide nanoparticles, the better the mechanical properties. As described above, in the present invention, nano-particles are further added in a solder-free solder using a tin-silver-copper alloy as a substrate to refine the tin-silver-copper alloy structure and suppress tin by utilizing the characteristics of the nanoparticle. The silver-copper alloy produces a coarse-grained intermetallic compound to increase its mechanical strength, inhibit the growth of the intermetallic metal after welding, and slow down the increase in the thickness of the intermetallic metal, thereby improving the soldering sin and the service life of the electronic product. Furthermore, the present invention selects the uniform blending of nano particles in a tin-silver-copper alloy by a rolling kneading method or a magnetic stirring method to smoothly manufacture a nano-composite lead-free solder, which is also advantageous for the promotion of soldering and blending. Quality and reduced manufacturing costs. While the present invention has been described in its preferred embodiments, the present invention is not intended to be limited thereto, and it is intended that various modifications and changes may be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a tin-silver (SnAg) alloy flip-chip bump attached to a wafer. 2A to 2E are schematic views showing the flow of a method for producing a nano composite lead-free solder composition according to a first embodiment of the present invention. 18 1360452 Replacement page on November 16, 100 Figures 3A to 3B are schematic views showing the flow of a method for producing a tin composite lead-free solder composition according to a second embodiment of the present invention. Figures 4A and 4B: Electron photomicrographs of a conventional tin-silver-copper (Sn3.5AgO.5Cu) lead-free solder alloy and its alloy microstructure reflowed to a copper pad of the wafer. 5A, 5B and 5C: a nano-composite lead-free solder alloy prepared by different amounts of titanium dioxide nano-particles in a tin-silver-copper error-free solder according to the present invention and an alloy microstructure bonded to a copper pad of a wafer Electron micrograph. Fig. 6 is an electron micrograph showing the microstructure of an interface alloy in which a titanium-titanium-copper nano-particle is added to a tin-silver-copper lead-free solder and a nano-composite lead-free solder alloy is reflow-bonded to a copper pad of the wafer. Fig. 7 is a graph showing the mechanical property analysis of different amounts of titanium dioxide nanoparticles added to the nanocomposite lead-free solder of the present invention. [Main component symbol description] 1 Lead-free solder laminate 10 Nano composite lead-free solder 11 Tin-silver-copper alloy sheet 12 Nanoparticle 2 Roller 30 Nano-composite error-free solder 31 Tin-silver-copper alloy 32 Nanoparticle 4 Container 5 Magnetic Stirrer 6 heating type electromagnetic stirrer 19

Claims (1)

1360452 - - November 16, 2010 Replacement Page VII. Patent Application Range: 1. A nanocomposite lead-free solder composition comprising: 0.01 to 5.0% by weight of silver, 0.01 to 3.0% by weight of copper, 0.25 to 2.0 The weight-% of the nanoparticle and the balance are tin, wherein the nanoparticle is selected from the group consisting of di-titanium oxide, aluminum oxide, zinc peroxide, cerium oxide, nanocarbon tube or a mixture thereof, and the naphthalene The particle size of the rice particles is between 5 and 500 • nanometer. 2. The nanocomposite lead-free solder group according to claim 1, wherein the nano-composite error-free solder composition is composed of tin-silver-copper alloy mixed with the nanoparticle. 3. The nanocomposite lead-free solder composition according to claim 2, wherein the nanoparticle is mixed into the tin-silver-copper alloy by rolling and kneading. 4. The nanocomposite lead-free solder composition of claim 3, wherein the nanoparticle is uniformly dispersed between a plurality of layers of tin-silver-copper alloy sheets of a lead-free solder laminate φ. 5. The nanocomposite lead-free solder composition of claim 2, wherein the nanoparticle is mixed into the tin-silver-copper alloy by magnetic stirring. 6. The nanocomposite lead-free solder composition of claim 1, wherein the silver content is selected from the group consisting of 2.5% by weight, 3.0% by weight, 3.5'% by weight, 3.8% by weight, 3.9% by weight, 4.0% by weight. , 4.5 weight • % by volume or 5.0% of halo. 7. The nanocomposite lead-free solder as described in claim 1 or 6 of the patent scope 20 1360452 100 years] January 6th replacement page composition 'where the copper content is selected from 0.5 weight 0.7% by weight, 0.8% by weight or 〇. 9% by weight. The nano-composite error-free soldering group described in the item, the content of the nanometer (four) is selected from **%'!.〇tt〇/o, tl5tt〇/〇〇重里/〇〇, 5 9二nt circumference The nanocomposite of the present invention is characterized in that the nanoparticle is selected from the group consisting of titanium dioxide and having a particle size of 10. The composition of the invention of claim 1 or 8 wherein the nanoparticle is selected; ^ ° : Wrong solder 30 to 40 nm. (4) One oxidation, one particle size is 1L, as claimed in the patent scope! Or 8 items of the composition, 1 兮 迚 迚 不 复合 复合 复合 复合 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 The rice particles are selected two, and the tin is 20 to 30 nm. The rolling is wrong, and its particle size is 13. For example, the scope of the patent application or the eighth component of the composition 'where the nano-micro (four) is from tin 2 to 10 nanometer. It is not ruthless, and its particle size is 14: Please refer to the nanocomposite-warfare described in 1 item, and also contain 0.01 to 0.5 heavy fiber field, and the product, including _ to 〇.5 wt% . ...口知锡组 21 1360452 - • Replacement page on November 16, 100. 4. Designation of representative drawings: ' (1) The representative figure of the present is: (6). - (2) A brief description of the symbol of the representative figure: * None 5. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: