TWI378841B - - Google Patents

Description

1378841 VI. Description of the Invention: [Technical Field] The present invention relates to a metal filler which can be used for connection and filling of various electronic parts, and a lead-free solder containing the same, particularly for lead-free solder for low temperature connection Flux" The present invention also relates to a connection structure obtained by using the lead-free solder, and a component mounting substrate having the connection structure and the substrate.

[Prior Art] Conventionally, as a flux used in reflow heat treatment, a Sn-37Pb eutectic solder having a melting point of 183 Å has been conventionally used. Further, as a high-temperature flux used in an electronic component requiring high heat resistance, a solid phase wire 27〇t and a liquidus line 305t are widely used: iSn_9〇pb high-temperature flux. However, in recent years, as shown by the environmental regulations (WEEE, R〇HS Directive), the harmfulness of Pb has become a problem. As a result, from the viewpoint of preventing environmental pollution, the flux has not progressed rapidly. In such a situation, as a generation of ^_37 eutectic solder (4), the gas-free flux of Sn3__5Cu contained in the vicinity of the melting point 22 () 〇c is more representative. As the reflow heat treatment condition of the error-free flux, the peak temperature is generally in the temperature range of about 240t to 260t. Compared with the 37Pb ytterbium flux, the lead-free solder containing Sn-3.〇Ag-〇.5Cu is about 220 Cb. Because of the high melting point of the alloy, the reflow heat conditions are only required to be higher. Recently, when there is concern about problems such as fossil fuel exhaustion and ball warming, it is expected that the energy-saving process and the low-carbon dioxide emission process will be established by making the reflow heat treatment low. In addition, it is expected that the low temperature of the reflow heat treatment temperature can suppress the thermal damage of the 146300.doc / leaf 丄 ^, electronic equipment and substrate materials, and the selection range of the substrate P that can be used is relatively wide. At present, as a representative example of a non-hybrid solder material which can be joined at a low temperature, there are Asn_58Bi eutectic solder 2 = two rnt), In (hyun 15rc), Sn 52in alloy solder (refining point), etc. (refer to the patent document 丨And ❻, after the welding of the flux materials, the refining of the flux material will cause re-melting when it is again at a temperature higher than the melting point. ▲In addition, the electronic device represented by the mobile phone is miniaturized, lightweight, and high. The trend of this trend is staggering. Following this, high-density mounting technology has continued to progress. It has been developed to store parts in the substrate, or to make a plural: LS: form a package, etc. for efficient use of limited volume. A variety of mounting techniques. On the other hand, the higher the density, the more the solder joints that are incorporated into the interior of the substrate or the inside of the package are subjected to heat treatment in the subsequent step. Therefore, the flux is re-smelted in the subsequent step. , & the gap between the part and the sealing resin flows out, and a short circuit occurs between the electrode of the part, etc., and a problem is becoming significant. Therefore, the part incorporated into the inside of the substrate or inside the package is connected. Among them, it is expected that the flux material will not be melted even if it is subjected to a plurality of heat treatments in the subsequent step. The inventors have proposed a kind of high heat-resistant solder (four) material, under the reflow heat treatment condition of the no-material agent, for example, the peak temperature of 246t. It can be melt-bonded and joined, and then turbulent under the same heat treatment condition τ (Patent Document 3 contains a mixture of the first metal particles of the metal particles contained in the flux material and the second metal particles having a lower melting point than the first metal particles. In the technique of Patent Document 3, ~ 146300. doc ^78841 is used as the second metal particle. The flux material is a second metal which is melted when it is subjected to reflow heat treatment at 232. The diffusion of the metal between the particles and the first metal particles is carried out, and the joint portion M having excellent heat resistance is formed to take into consideration the demand for energy saving and low carbon dioxide emission, and the application of the substrate (4) having low heat sealing property and electronic equipment. A material that can be joined at a lower temperature and does not re-melt under the reflow heat treatment conditions of lead-free solder after bonding.

Therefore, the inventors of the present invention have proposed a flux material which can be melt-bonded at a low temperature of 149 C or higher at a peak temperature, and has heat resistance at 26 (after heat bonding (Patent Document 4). The conductive filler is a mixture of the first metal particles and the second metal particles having a higher melting point than the second metal particles. Further, as a flux paste containing a plurality of metal particles and capable of low-temperature bonding, it is proposed to use A flux paste of a mixture of a Cu powder and a Sn-Bi powder (see Patent Document 5). [Prior Art Document] [Patent Document] [Patent Document 1] JP-A-2001-334386 [Patent Document 2] [Patent Document 3] International Publication No. 2006/109573 [Patent Document 4] JP-A-2008-183582 (Patent Document 5) JP-A-2008-200718 (Invention) [ The problem that the invention wants to solve]

14630〇.d〇Q 1378841 However, in the technique described in Patent Document 4, there is room for improvement in the joint strength at room temperature after the mouth is removed. In addition, the patent document goes to "Technology of 4". In the use of In, Ag, etc., a mussel metal for the first metal particles, the material cost is high and the alloy composition is complicated, so there is a problem that the manufacturing cost is high. In the technique described in Patent Document 5, the Cu powder is easily oxidized, and if it is hygroscopic, it is more strongly coagulated, and thus the storage stability is problematic. Further, in the techniques described in the documents 4 and 5, there is room for improvement in joint strength at room temperature after joining. The present invention has been made in view of the above problems, and an object thereof is to provide a metal filler which can be cooled at a lower temperature than a reflow heat treatment condition of a Sn-37Pb eutectic solder (for example, a peak temperature of 16 Å. The bonding strength is good at room temperature after bonding. The object of the present invention is to provide a lead-free solder containing the metal filler, a connection structure obtained by using the lead-free solder, and a component having the connection structure and the substrate. [Means for Solving the Problem] [1] A metal filler comprising a mixture of a first metal particle and a second metal particle, the first metal particle containing 7L of the highest mass ratio as a main component Cu, and further comprising an alloy particle, wherein the second metal particle contains 4% to 7〇% by mass, and is selected from the group consisting of

Cu alloy and one or more kinds of metals in the Sn group are from 3 to 60% by mass of the Bi alloy particles, and the amount of the second metal particles is from 40 to 300 parts by mass relative to the first metal particles of from 1 to 146,300. The metal filler according to the above [1], wherein the second metal particles contain Sn. [3] The metal filler according to the above (1) or [2] wherein the average particle diameter of the metal particles and the second metal particles are in the range of 5 to 25. [4] The metal filler according to any one of the above [1], wherein the first metal particles further comprise a metal selected from the group consisting of Ag and the above. [5] The metal filler according to any one of the above [1] to [4] wherein the first metal particle contains Ag 5 to 15% by mass, Bi 2 to 8 mass%, cu 49 to 81 mass%, and In 2 to 8 mass%, and Sn 1〇~2〇f amount 0/〇, the first metal particle has a temperature of 230 to 30 (differential heat observed in the range of TC) under differential scanning calorimetry (DSC) The peak, and at least one endothermic peak observed in the range of 480 to 530 ° C. [6] A lead-free solder comprising the metal filler according to any one of the above (1) to [5]. [7] a structure including a second electronic component, a second electronic zero-receiving member, and a flux bonding portion for bonding the first electronic component and the second electronic component, wherein the solder bonding portion is described in the above [6] The substrate is formed by a reflow heat treatment. The m-type component mounting substrate has a substrate and the connection structure described in the above [7] mounted on the substrate. [Effect of the Invention] The metal filler of the present invention and the like A lead-free solder of a metal filler which can be used at a low temperature than a reflow heat treatment condition of, for example, a Sn-37Pb eutectic solder (For example, the peak degree is 160 C or more), the fusion bonding is performed, and even if it is subjected to a plurality of heat treatments after the joining in the subsequent step, the two squid buckets 4 are not melted again. The effect of preventing the short circuit caused by the remelting of the flux generated by the poles of the genus 1 is obtained. 2 ^ In addition, the metal filler of the present invention and the error-free tamping agent containing the metal filler can be connected to I & [Embodiment] <Metal filler> The metal filler of the present invention includes a metal filler of a metal particle and a second metal particle. The first metal particle contains, as a main component, a Cu alloy particle of the sum of the mass of the bismuth, Cu (copper), and further contains In (indium) and = (tin), and the second metal particle system Including ugly (four) 4 (four) mass % and one or more metals selected from the group consisting of Ag (silver), Cu (copper) 'In (steel), and Sn (4), 3 〇 to 6 〇 mass% of the alloy particles, and the second The amount of metal particles is relative to the first genus 4 Θ I genus 100 罝 罝 4 0 to 30,000 parts by mass. In the present invention, the melting point of the first metal particles by the combination of the second metal particles and the second metal particles is set to be higher than the melting point of the second metal particles. Reflow heat treatment, melting of the second metal particles having a lower melting point than the second metal particles 'the alloying reaction between the metal particles and the molten second metal particles due to thermal expansion: forming a higher stability than the melting point of the second metal particles Alloy phase. In a typical embodiment, the first metal particles are not melted at a reflow heat treatment temperature when the materialless agent of the present invention is used. Thereby, the flux-free solder containing the metal filler of the present invention can be fusion-bonded under low temperature conditions (typically low temperature conditions under the reflow heat treatment conditions of the ^37Pb eutectic solder), 146300.doc 丄j/8841 and after fusion bonding' It has the effect of no longer melting under heat treatment. It can be used at low temperatures and can be used in energy-saving processes and low-carbon dioxide emissions processes, and is advantageous in terms of thermal damage such as electrical and electronic equipment and substrate materials that can be suppressed. In the present invention, the group D ′ of the first metal particles and the second metal particles having the above composition can avoid the problem of agglomeration due to moisture absorption when using, for example, Cu powder. Further, in the present invention, the ith metal particles have Cu as a main component and 镰M to a genus particle contain a large amount of B i . Thereby, it is possible to provide a metal filler which can be melt-bonded at a low temperature and has a good bonding strength at room temperature after bonding, and can reduce the amount of use of a high-valent metal such as In or Ag. [First Metal Particle] The first metal is mainly composed of Cu. That is, the mass ratio of Cu among the elements constituting the first metal particles is the highest. The first metal particles further contain In and Sn in addition to Cu. Take this, the first! Metal particles can form a quasi-stable alloy phase. The formation of the quasi-stable alloy phase promotes the combination of the second metal particles and the second metal particles, so that a good bonding strength can be obtained during the melt bonding at a low temperature. In addition to TCu and InASn, the first metal particles are preferably one or more selected from the group consisting of Ag and Bi, in addition to the viewpoint of the alloying of the second metal particles. In a preferred embodiment, the first metal particles comprise Ag 5 to 15 mass. /. , out of 2 to 8 quality. /〇, Cu 49~81% by mass, In 2~8f amount % ' and Sn 1〇~2〇% by mass. Furthermore, it is also possible to contain unavoidable impurities at this time. In the preferred aspect, the first! The metal particles have at least one exothermic peak observed in the range of 230 to 300 t in differential scanning calorimetry (DM), and at least one endothermic peak is observed in the range of J46300.doc 1378841 and in the range of 480 to 530 °C. The peak of the heat observed in the range of 230 to 300 ° C, indicating the first! The metal particles form a quasi-stable alloy phase, and an endothermic peak observed in the range of 480 to 530 ° C indicates the melting point of the first metal particles. Further, the melting point described in the present specification means the solidus temperature determined by differential scanning calorimetry (DSC). Further, the above-described difference scanning heat measurement is typically carried out in a nitrogen atmosphere at a temperature increase rate of 10 ° C / min, in the range of 40 to 58 (rc measurement range. In a better aspect, the first metal The particles include Ag 5 to 15% by mass, 2 to 8% by mass, Cu 49 to 81% by mass, In 2 to 8 % by mass, and Sn 1 to 2% by mass, and the first metal particles are inferior. In the scanning calorimetry (Dsc), there are at least one exothermic peak observed in the range of 230 to 300 t, and at least one endothermic peak observed in the range of 480 to 530 ° C. The average diameter of the first metal particle is When the average particle diameter of the metal particles is 2 μηι or more, the specific surface area of the particles is small. Therefore, when the flux is formed from the metal filler of the present invention, for example, using a helping agent described later. The life of the contact surface solder paste of the first metal particle and the flux is longer. Further, when the flat diameter of the i-th metal particle is 2 or more, the reduction of the metal filler in the source self-flux can be reduced in the reflow heat treatment. The reaction (ie, the removal of the oxide film of the metal filler particles) The gas can reduce the voids generated inside the flux connection. In addition, from the viewpoint of the strength of the detailed paste, the average diameter of the metal particles is preferably below (4). When the particle size is too large, the gap between the particles becomes large. Therefore, it is easy to damage the dryness of the agent paste, and the part is easily detached from the time when the tantalum-bonded part is placed to the reflow heat treatment bundle. The average particle diameter of the first metal particles is 146300.doc 1378841, which is more preferably in the range of 5 to 25 μm. In addition, the average particle diameter in this specification is a value measured by the laser diffraction type particle diameter distribution measuring apparatus. • [Second metal particle] • The second metal particle contains Bi 40 to 70% by mass, and The metal of one or more of Ag, cu, In, and Sn is 30 to 60 mass%. / 〇. In addition, the unavoidable impurities may be contained at this time. The second metal particle may be returned to φ by the above composition. Melting during the heat treatment is favorably achieved by alloying between the first metal particles and the molten second metal particles due to thermal diffusion. • The content of Bi in the second metal particles is melt-bonded at room temperature. , and obtain room temperature after bonding Viewpoint of good bonding strength of view, based ./ ^ 4〇 mass above 70% by mass or less. The content of the above-described mass is preferably 5〇~6〇%.

The content of the metal selected from the group consisting of Ag, Cu, In, and the like in the second metal particles is 30% by mass or more from the viewpoint of achieving good metalization of the metal particles and the second metal particles. It is contained in a sufficient amount from m: in the second metal particle, it can be melted and joined at a low temperature, and is not more than 6% by mass. The above content is preferably 4 Å to 5 Å by mass. It is preferred that the genus genus particles contain Sn. In this case, a metal filler can be provided, and the low-temperature melting property and the bonding property of the metal filler are good, and even if the fusion bonding at a low temperature is performed, the Sn content in the good bonding strong particles is 40 to 5 〇 mass%. Preferably. "The first choice is from the 1" 1 ... metal 7 to improve m to improve low melting point, mechanical strength, etc. 146300.doc 11- 1378841 In addition, from the viewpoint of low temperature meltability and jointability, the second The metal particles are more preferably Sn-Bi-based alloy particles. Further, it is preferably a eutectic composition (typically Sn_58Bi) 2Sn Bi-based alloy particles which is less likely to cause solidification defects and segregation.

The Sn-Bi-based alloy particles are typically composed of only yttrium and yttrium as constituent elements (but may contain unavoidable impurities), but are preferably selected from Ag, Cu for the purpose of improving ductility, improving low melting point and mechanical strength. And one or more metals in the sputum. The average diameter of the second metal particles is preferably in the range of 5 to 40 μm from the viewpoint of the same as the average particle diameter of the first metal particles, that is, from the viewpoint of the reactivity with the flux and the adhesion of the solder paste. The first! The average particle diameter of the metal particles is more preferably in the range of 5 to 2 5 μm. [Mixing of First Metal Particles and Second Metal Particles] The metal filler of the present invention contains a mixture of the second metal particles and the second metal particles. In the metal filler of the mixture, the amount of the second metal particles (hereinafter also referred to as "the mixing ratio of the second metal particles") is in the range of 40 to 300 parts by mass based on 1 part by mass of the second metal particles. When the mixing ratio of the second metal particles is 4 Å or more, the ratio of the presence of the molten component during the reflow heat treatment in the metal filler is increased, so that the fusion bonding at a low temperature can be favorably performed, and for example, it can be used as a flux after bonding. With good physical strength. On the other hand, when the mixing ratio of the second metal particles exceeds 1 part by mass, a more excellent physical strength can be obtained. On the other hand, when the mixing ratio of the second metal particles exceeds 3 Å by mass, the proportion of the stable alloy phase having a high melting point formed by the reaction between the molten second metal particles and the second metal particles is small, and thus heat resistance cannot be obtained. . From the viewpoint of physical strength and heat resistance of the flux joint portion, the mixing ratio of the second metal particles 146300.doc 12 1378841 is preferably in the range of 100 to 300 parts by mass. The particle size distribution of the first metal particles and the second metal particles may be in accordance with the use of the solder paste. For example, in the screen printing application, 纟 attaches great importance to the problem that the amount of transfer of the solder paste on the substrate is small, and the particle size distribution is better with the addition of the palace; in the distribution use and the use of the through hole filling, the liquidity and the hole are emphasized. Under burying, it is better to sharpen the particle size distribution. As mentioned above, from the viewpoint of reactivity with flux and characteristics of solder paste, the first! The average particle diameter of the metal particles and the second metal particles is preferably in the range of Η(4)′ and 5 to 40 Å, and more preferably, the average particle diameter of the ith metal particles and the second metal particles are both 5 to 25 Å. range. For example, in combination with a flux, the metal filler of the present invention can form a paste. When the component is mounted using the error-free solder, there is a case where a flux layer is formed on the surface of the solder joint portion formed particularly by the solder trace portion. If the fine particles of the metal filler in the average particle layer of the metal filler are in the state of floating X, the metal particles are easy to follow each other, and the parts joined by the flux are supplied to the subsequent aid agent for washing. In the net step, the particle of the metal filler in the cleaning liquid is produced =: the defect of the part. When the first metal particle and the second metal particle are controlled to be 5_, the part is installed in the flux layer, and the sub-component The micro-pillars of the production 1 will be difficult to follow. It can inhibit the floating particles in the layer of the aiding agent: it can reduce the amount of particles that the cleaning liquid will flow out. The other side: the average of the paste particles and the second metal particles The particle size is below 25 (four) or less. "The dryness of the agent is not easily damaged, so it is preferable. The bright spot of the second metal particle is preferably in the range of 80 to 160 ° C, more preferably 146300.doc 13 1378841 100~ In the typical embodiment, the second metal particles are melted at the reflow heat treatment temperature when the lead-free solder of the present invention is used. Further, the first metal particles and the second metal particles specified in the present specification. The composition of the elements. For example, it can be combined The ICP (ICP) luminescence analysis and the like are confirmed (10). In addition, the element 3 of the particle profile can be analyzed by sem-EDX (characteristic X-ray analysis device). As a method for producing the second metal particle and the second metal particle, respectively. As a method of producing the fine powder, a well-known method can be employed, but a rapid solidification method is preferred. Examples of the method for producing the fine powder by the rapid solidification method include a water spray method, a gas spray method, and a centrifugal spray method. Etc. In terms of the oxygen content that can be suppressed, the gas method and the centrifugal spray method == the second two" use inert gas such as nitrogen, nitrogen, helium, etc. The line speed, the speed of cooling is 5,5_t / sec. The second degree of continuous formation on the disc - 硪 ~ spray method, by rotating in the circle _ 〇Ν) is better, the disc rotation speed is two to the celen. The rate of abuse is in the range of 64 to 120,000 rpm. <Lead-free tincture> The present invention also provides a seed. The content of the metal of the present invention is (U^;: error-free), and refers to the metal filler component and the second aid: according to the environmental regulations. The lead-free solder is preferably included in the solder paste containing the wound. The lead-free 146300.doc j37B841 bismuth agent of the present invention is more typically composed of a metal filler component and a fluxing component, and may also contain the above-mentioned material of the n-n metal filler, but in the non-destructive Inventive effect / metal filler. As the content of the metal filler component in the above solder paste, from the solder sound] η poetry. Take the dragon's point of view, for the detailed d paste 100 quality ο / ο in the 84~94 The quality s is better now. The above range with better right distance can be used in the flux paste, / tongue. h. For example, in screen printing applications, the solder paste is applied to the substrate. Q7 Q1 ^ θ In the case of "in the case of ^, the above content ratio is preferably in the range of 87 to 91%.

^ m feet live in the range of 88 to 90% by mass. In the distribution use, it is important to pay attention to the discharge fluidity 0/ _. The above 3 yield is preferably in the range of 85 to 89% by mass, more preferably 86 to 88% by mass. The flux component contains rosin, a solvent active agent, and Thixotropic agents are preferred. The flux composition as described above is suitable for the surface treatment of the metal filler. That is, by removing the oxide film of the metal filler component in the solder paste during the reprocessing, _ re-emulsification can promote the melting of the metal and the alloying due to thermal diffusion. As a component of the flux, well-known materials can be used. <Connection Structure> The present invention also provides a connection structure including a first sub-part, a second electronic component, and a solder joint portion s joining the first electronic component and the second electronic component The above-described materialless agent of the present invention is subjected to a reflow treatment to form the flux joint portion. The combination of the i-th electronic component and the second electronic component includes a combination of a substrate electrode and a mounted component electrode. A method of joining the phantom electronic component and the second electronic component for forming the connection structure of the present invention is a method in which a solder paste is applied to a substrate electrode, and a component electrode is mounted thereon, and then joined by a reflow heat treatment; The 146300.doc 1378841 two-piece electrode or substrate electrode is coated with a solder paste, and is formed by reflow heat treatment. Then, the component electrode and the substrate electrode are overlapped and mounted again by reflow. Method and so on. In the above case, the electrode can be joined by a solder joint. The temperature of the reflow heat treatment of the door is 100~·. The range of c is preferably better. The reflow heat treatment temperature is typically 4: it is set so as not to reach the melting point of the first metal particles and above the bright point of the second metal particles. When the electrode electrode plate electrode of the electronic device or the like is mounted by using the lead-free solder of the present invention, when the heat is applied to the melting point of the D metal particles or more, the second metal particle is melted, and the second metal particle is melted. The metal particles and the mounted component electrodes are bonded to the substrate electrodes. At this time, the thermal diffusion reaction is accelerated between the metal of the i-th metal particle and the second metal particle, and the synthesis is higher than the melting point of the second metal particle. The new stable alloy phase is formed to form the i-th metal particle and the electrode of the connected component. A connection structure to the substrate electrode. The new stable alloy phase has a higher refining point than the Sn-3.〇Ag-0.5Cl^ non-correcting flux (e.g., about 260 t), and does not melt even if it is subjected to a plurality of heat treatment fluxes in the subsequent step. According to the present invention, it is possible to prevent a short circuit generated between the electrodes of the parts due to remelting of the flux. <Parts-mounted substrate> The present invention also provides a component mounting substrate having a substrate and the above-described connection structure of the present invention mounted on the substrate. [Examples] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto. 146300.doc -16- 1378841 [Example 1] (1) Production of first metal particles Cu 6.5 kg (purity of 99% by mass or more), Sn i 5 kg (purity of 99% by mass or more), Ag of 1.0 kg (purity) 99% by mass or more), 5 kg (purity of 99% by mass or more) and In 〇·5 kg (purity of 99% by mass or more) (ie, target constituent element, Cu: 65 mass% 'Sn: 15% by mass' Ag : 1 〇 mass 〇 / 〇, Bi: 5 mass. / 〇, and 111: 5 mass%), placed in graphite crucible, heated to 140 by high frequency induction heating device in a 体积 atmosphere of 99 vol% or more Then, the molten metal is introduced into the spray chamber of the helium atmosphere from the tip end of the crucible, and then helium gas is ejected from a gas nozzle provided near the tip end of the crucible (purity of 99% by volume or more, and oxygen concentration is less than 1% by volume). , the pressure of 2 5 Μρ &) was atomized to produce the first metal particles. The cooling rate at this time was 26 〇〇 it / sec. Using the air flow classifier (Nissin Engineering: TC_15N), the i-th metal particles were 20 μηι setting for classification, after recovering large particle fractions, set again with • 3〇μηι setting for small fractionation Sub-portion. The recovered alloy particles were measured by a laser diffraction particle diameter distribution measuring device (HEL〇S & R〇D〇s), and the average particle size was 丨5”μηι. The differential scanning calorimeter (Shimadzu Corporation). DSC-50) The temperature of the heating solution was measured at a temperature of 1 〇 in a nitrogen atmosphere. The range of 40: 580 C was measured in the range of 40 to 580 C, and was measured at 5 〇 2 <> c and 521 核. The endothermic peak can be confirmed by the plurality of melting points thus displayed, and the presence of a plurality of alloy phases is detected. Further, an exothermic peak is detected at 258t and 282t, and the presence of the quasi-stable alloy phase can be confirmed. Hereinafter, it is referred to as a first metal particle A. I46300.doc • 17- 1378841 Similarly, the first metal particles obtained by atomization are classified by a setting of 1 〇 0 claws, and after recovering a large particle portion, again, 2 〇 μηη The fractionation was carried out to recover small particle fractions, and the recovered alloy particles were measured by a laser diffraction particle diameter distribution measuring apparatus (HELOS & RODOS) to find that the average particle diameter was 8.1 μη. The second metal particle B. Similarly, the ruthenium metal particles obtained by atomization are set at 16 μm, and the large particle fraction is recovered, and then fractionated by 1 , to recover the small particle fraction. The recovered alloy particles are The laser diffraction type particle diameter distribution measuring apparatus (HELOS & ROD〇s) measured the average particle diameter of 2·7 μπι^ and the obtained i-th metal particles were hereinafter referred to as the second metal particles C. Similarly, the first metal particles obtained by atomization were classified by setting 3 μ μm to recover large particle fractions. The collected alloy particles were measured by a laser diffraction particle diameter distribution measuring apparatus (HELOS & RODOS), and the average particle diameter was found to be 30.2 μη. The obtained metal particles are hereinafter referred to as work metal particles D. (2) Production of the second metal particles The second metal particles were obtained by using a flux powder of 25 μm to 45 μηη, manufactured by Seishi Metal Co., Ltd., and a flux powder Bi_42Sn (element composition, (1): 58% by mass, Sn: 42% by mass) (hereinafter referred to as the second metal particle A), or the flux powder of the particle size of 1 〇μιη to 25 μηι, manufactured by Yamaishi Metal Co., Ltd. (element composition, Bi: 58% by mass, Sn: 42% by mass) (Hereinafter, it is described as the second metal particle B). By differential scanning calorimeter (Shimadzu: dsc_ 146300.doc • 18- 1378841

50) The melting point measured under the same measurement conditions as described above, both the second metal particles A and the second metal particles B were 138 °C. Further, the second metal particles a and the second metal particles B were measured by a laser diffraction type particle diameter distribution measuring apparatus (HELOS & RODOS), and the average particle diameters thereof were 35 Å and 20.4 μηη, respectively. (3) Preparation of lead-free solder paste The above-mentioned second metal particles Α and the second metal particles _ + A were mixed at a mass ratio of 100 : 300 as a metal filler component. Next, the metal filler component is mixed with 89.5 mass% and the auxiliary agent (A) l〇.5 mass. /. A solder paste was prepared by sequentially applying a solder softening machine (MARUKOMU: SPS-1) and a defoaming kneader (Songo industry: snb_350). (4) Measurement of joint strength (shear strength) The above-mentioned solder paste was printed and applied on a Cu substrate having a size of 25 mm × 25 mm and a thickness of 〇 25 mm, and mounted on a wafer having a size of 2 mm × 2 mm 'thickness 〇 5 claws. Reflow heat treatment at a peak temperature of 16 〇t in a nitrogen atmosphere. The heat treatment apparatus used a reflux simulator (MARUKOMU: SRS-1C). The temperature distribution is from 丨5«c / sec from heat treatment (normal temperature) to 120 C, from 120 °. (: After 1 sec. gradually warmed up to 135 〇 c, the temperature was raised by 2. 〇 ° C / sec and kept at the peak temperature for 15 seconds. The printing pattern was formed using a screen printing machine (Micr〇tek) : MT-320TV. The printing cover is made of metal and the applicator is made of urethane. The opening size of the cover is 2 mm x 3.5 mm and the thickness is ^ mm. The printing condition is speed 5 〇 mm / wear > , printing pressure 〇 1 MPA, squeegee pressure 〇 2 MPa, back pressure 〇 · 1 MPa, invasive angle 20. 'Pitch 0 mm, printing times is 1. 146300.doc -19- 1378841 Then, at room temperature ( 25. The cutting direction of the sample prepared as described above: the wafer bonding strength is measured by the load measuring device at a pressing speed, and is converted into a value per unit area, which is 15 4 . The sample prepared above was heated to 26 Torr on a hot plate, and after holding for 3 minutes, the wafer bonding strength in the shear direction was measured in the same manner as described above, and the value per unit area was 0.35 MPa. It can be confirmed that the sample has a heat resistance of 26 even when the TC is heated. Further, it can be protected. The bonding strength is a bonding strength of 〇. 2 〇 MPa or more. ', [Examples 2 to 10, Comparative Examples 2 and 2] The mixing ratio of the first metal particle A to the second metal particle is changed. A solder paste was prepared in the same manner as in Example 金属, and the wafer bonding strength was measured in the same manner as in Example 1. The results are shown in Examples 2 to 5 of the Table and Comparative Examples, respectively. The temperature distribution of the Cu wafer when the Cu wafer was joined was the same as that of the example 丨5 to 5, and the temperature was adjusted from 1.5 C / sec from the heat treatment (normal temperature) to 12 (Γ (:, from 12 〇 after 110 seconds) After gradually raising the temperature to l35 ° C, the temperature was raised by 2 (rc / sec, and maintained at a peak temperature of 180 ° C for 15 seconds, and the results are also shown in Examples 6 to 10 and Comparative Example 2 of the Table. As a result of the comparative example, it is apparent that when the first metal particles are not contained, the flux joint portion (joining portion) is melted when heated at 26 ° C, so the shear strength is 〇 MPa. On the other hand, it is understood that the first metal is contained. In the examples 1 to 1 of the particles, even when heated by 26 〇. The bonding strength is also 0.2 MPa or more, and the flux is not melted. Further, in the present specification, the flux is not remelted, and the bonding strength is 〇2〇MPaw 146300.doc -20-1378841 [Comparative Example 3] Using the previous representative lead-free solder (Sn-3.0Ag-〇_5Cu) paste, the same method as in Example 1 (4) was carried out (the measurement of the bonding strength of the wafer was carried out. The results are shown in Table 1. However, The reflow and temperature distribution when bonding the Cu flakes using the flux material is carried out by heating from the beginning of the heat treatment (normal temperature) to l4 〇 ° C in seconds, and then gradually heating from 140 ° C to 11 〇 to 17 〇 » c after 2.0 C/sec is raised from 170C to 250. (:, and maintained at a peak temperature of 25 〇 ° C for 15 φ seconds. From the results of Comparative Example 3, it is known that when a representative lead-free bismuth Sn-3.OAg-0.5Cu is used, flux bonding at 260 ° C heating The part was melted, and the bonding strength was 0 MPa. [Examples 11 to 20] Using the metal filler component in which the mixing ratio of the first metal particles B and the second metal particles B was changed, a solder paste was produced in the same manner as in Example ,, and further The reflow heat treatment was carried out at a peak temperature of 160 C or 180 C (the same as in Examples 1 to 10), and the joint strength was measured in the same manner. The results are shown in Table 2, Examples 11 to 20. According to Table 2, it is found that In Examples U to 20 of the i-th metal particles 8, the bonding strength of 〇2 MPa or more was also exhibited in the case of heating, and the heat resistance in the bonded state was exhibited. [Example 21] On the Cu substrate of the printed circuit board of the heat-resistant epoxy resin glass cloth, (4) (4) The error-free flux prepared in the second embodiment is equipped with a 0603-size laminated ceramic f crystal moon f container (hereinafter abbreviated as _3C, or a single-loaded component), 乂Shell = Example 1. „Contained conditions for reflow heat treatment, making samples Next, the sample prepared above was applied to the hot plate at 1 G5. (: heating, the underfill was applied to the upper portion of the mounting part without covering the upper portion of the mounting part, and the hardener was hardened at 165 ° C in an electric furnace. Then, the transparent molding resin was applied to the upper part and the periphery of the mounting part and hardened by electric furnace for 4 hours. Then, after absorbing 40 C and 60% RH for 40 hours, the peak temperature was 260 eC in a nitrogen atmosphere. Reflow heat treatment. The heat treatment device uses reflux simulation (MARUKOMU: SRS-1C). The temperature distribution is increased from 1 to 5 °C from the start of heat treatment (normal temperature) at i 5 °c / sec, and 1 〇 from 150 ° C. The leap second gradually warms up to 21 (after TC, then raises the temperature from 21 〇t to 26 (TC at 2.0 eC/sec, and maintains the peak temperature at 260 C for 15 seconds. Then, the flux is melted by reflow treatment, and the parts are visually observed. Whether the electrodes were short-circuited between the electrodes. The results are shown in Table 3. It was confirmed that in Example 21, the short circuit between the component electrodes was not observed, and the heat resistance of the flux material at 260 ° C was not observed. [Comparative Example 4] The same method as in Embodiment 21, Evaluation of the previous representative lead-free solder Sn-3.0Ag-0.5Cu. However, the temperature distribution is different only when 〇6〇3C is mounted, and the temperature is raised to 140 C from the heat treatment (normal temperature) at 1.51:/sec. C gradually warmed up to 17 经过 after 1 〇〇 second, then increased from 210 C to 250 ° C at 2.0 C / sec, and at a peak temperature of 25 (TC maintained for 15 seconds. The results are shown in Table 3. From Table 3 As is clear from the results, in Comparative Example 4, the flux was melted at a very high probability, and a short circuit occurred between the electrode electrodes. On the other hand, in Example 21, although the melting point of the second metal particles was i38 ° C, no short circuit between the component electrodes occurred. From the above results, it is understood that the use of the flux-free flux of the metal filler of the present invention allows joining of parts at a low temperature, and even after reflow, the solder 146300.doc-22-1378841 does not melt and flow out, and is a material excellent in heat resistance. . [Example 22]

The first metal particle A and the second metal ion A are mixed at a mass ratio of 100: 186 as a component of the metal filler. Then, a flux paste was prepared by mixing the metal filler component of 9% by mass and 10% by mass of the flux (B) in the same manner as in Example 。. Applying a solder paste to the electrode of a printed circuit board containing a high heat-resistant epoxy resin glass cloth, and mounting a film of a 5 size resistor (hereinafter referred to as 1005R. or simply as a mounting part), under a nitrogen atmosphere Take the peak ^ degrees 160. (: The conditions of the reflow heat treatment were carried out, and the sample of the sample was obtained by embedding the k-type oxygen tree, and the cross-section polishing was performed to observe the joint part of the mounted part. 'The flux existing in the upper layer of the solder of the joint part of the mounting part was calculated. The number of metal particles (floating particles) present in the layer in a floating state (ie, the state in which the metal particles are separated from each other). The results are shown in the table [again, the number of floating particles that are not angry, the system will calculate _R 6 The value of the floating particles at the joint is taken as the average.

[Examples 23 to 24J In place of the first metal particles A of Example 22, the same evaluation was carried out using the i-th metal particles 8 or the first metal particles C. The results are shown in Table 4. As is clear from the results of Fig. 4, when the α-based particles c having an average particle diameter of 27 (4) were used, it was observed that a large amount of floating particles in the flux layer of the upper portion of the solder at the joint portion was used, and an average particle size of the metal particles was used. When the first metal particle of the first diameter of 15.1 μm is the first metal particle, it is known that the number of floating particles generated in the flux layer is small. l Thus, when the diameter of the metal particles used is small (for example, 2_7 μηη), it is known that the average particle size is, for example, μ 146300.doc -23- 1378841 and 15.1 μπι. The advantage that floating particles are less likely to be generated in the flux layer can be obtained. [Examples 25 to 27] The i-th metal particles VIII and the second metal particles 〇B were mixed at a mass ratio of 1 〇〇: 186 as a metal filler component. Next, a metal filler component of 89 5 mass = and a flux (Β) of 1 〇·5 mass% were mixed, and a paste was prepared in the same manner as in the example. The obtained solder paste was printed and applied on an aluminum telluride substrate, and the adhesion was measured using a standing tester (manufactured by MARUKOMU Co., Ltd.) ΤΚ-1. The results are shown in Example 25 of Table 5. The adhesion was measured at 5 points, and the average value thereof was not shown in Table 5. Further, in place of the second metal particles, the second metal particles β or the first metal particles D were used, and a solder paste was prepared in the same manner as in Example ,, and the adhesion was measured in the same manner. The results are shown in Example 26 and π of Table 5, respectively. From this, it can be seen that the average particle diameter of the metal particles used is the same as that of the metal particles d (average particle diameter: 30.2 μηι), and the average particle diameter is, for example, 8.1 μm and 15.1 μm. The advantage of being strong as a solder paste showing a high adhesion value is obtained. [Examples 28 and 29] The first metal particles a and the second metal particles were mixed at a mass ratio of 100:186 as a metal filler component. Then, a flux paste was prepared by the same procedure as in Example 1 by mixing a metal filler component of 9% by mass and a flux (B) of 10% by mass. Using the obtained solder paste as in Example 1 (4), a Cu wafer bonded substrate was prepared by a reflow heat treatment at a peak temperature of 16 (rc) under a nitrogen atmosphere, and the joint strength at room temperature and heating at 26 〇t was measured. Example 28 in Table 6. 146300.doc • 24· 1378841 In addition, the second metal particles A and the second metal particles B are mixed as a metal filler component at a mass ratio of 1 〇〇: 186. Then the metal filler component is mixed 89 5 Quality: /., and flux just 5% by mass 'The flux was prepared in the same manner as in Example i, and in the same manner as in Example 1 (4), a reflow heat treatment was performed under a nitrogen atmosphere at a peak temperature to prepare a μ piece. Bonded substrate measurement; ^ and 26 (bonding strength at TC heating. The results are shown in Table 2, [Comparative Examples 5 and 6] Mixed at a mass ratio of 100: 186 (^Flour (Futian Metal Foil Powder Industry Co., Ltd.) system,

The Cu-HWQ average particle diameter of 15 μm) and the second metal particle A' are used as metal filler components. Then, the metal filler component was mixed at 9 mass%, and the flux (m) was mass%, and a solder paste was prepared in the same manner as in the example (4), and the obtained paste was used in a nitrogen atmosphere in the same manner as in the example 1 (4). Next, a reflow heat treatment was performed at a peak temperature of 16 generations to prepare a Cu wafer bonded substrate, and the joint strength at normal temperature and heating at 260 ° C was measured. The results are shown in Comparative Example 5 of Table 6. In addition, it is mixed with a mass ratio of 100: 186. Powder (Cu-HWQ IS μηΐ, manufactured by Futian Metal Powder Industry Co., Ltd.) and the second metal particles 3' were used as metal filler components. Then, a flux paste was prepared by mixing the metal filler component of 89.5 mass% and the flux (〇) of 1 〇 5 mass% in the same manner as in the first embodiment. In the same manner as in Example 1 (4), a paste obtained by subjecting the obtained paste to a reflow heat treatment at a peak temperature of 16 Torr in a nitrogen atmosphere was used to prepare a Cu wafer bonded substrate, and the joint strength at room temperature and heating at 260 ° C was measured. The results are shown in Comparative Example 6 of Table 6, 〇Comparative Example 28 and Comparative Example 5 or Example 29 and Comparative Example 6, 146300.doc -25-1378841 and Bi-42Sn and Cu powder of 苐2 metal. In the combination, it was found that the combination of Bi-42Sn and the first metal particles A using the second metal was excellent in bonding strength at normal temperature. [Comparative Examples 7 and 8] The following evaluations were carried out in comparison with the prior art of the present inventors (JP-A-2008-183582). Production of the third metal particles: 1.0 kg of Ag particles (purity of 99% by mass or more), 2 particles of Bi particles (purity of 99% by mass or more), 1.5 kg of Cu particles (purity of 99% by mass or more), and 2.0 kg of chemical particles (purity) 99% of the quality of summer and above), Sn particles of 3 5 kg (purity of 99% by mass or more) (ie, the target constituent element, Ag: 丨〇 mass. / 〇, Bi: 2 〇 mass%, Cu. 15 mass%, In : 20) Mass %, and Sn · 35 mass %) were placed in graphite crucible at 99 volumes. The atmosphere τ above / 〇 is melted by heating to 1400 C by a high frequency induction heating device. Next, the molten metal is introduced into the spray chamber of the helium atmosphere from the tip end of the crucible, and then helium gas is discharged from a gas nozzle provided near the tip end of the crucible (purity of 99% by volume or more, oxygen concentration is less than 〇.丨% by volume, pressure 2.5) MPa) was atomized to produce a third metal particle. The cooling rate at this time is 2600 C / sec. The obtained third metal particles were observed by a scanning electron microscope (manufactured by Hitachi, Ltd.: s_27〇〇) and found to be spherical. The metal particles were classified by a gas flow classifier (TC-15N manufactured by Nissin Engineering Co., Ltd.) at a setting of 5 μm, and a large particle fraction was recovered, and then fractionated again by 15 μπι β to recover small particle fractions. . The 3rd to genus particles recovered by the laser diffraction type particle 彳 two-knife measuring device (Hel〇s & r〇d〇s) were determined to have an average enthalpy of 5.5 μm. The third metal 146300.doc -26·1378841 particles thus obtained were used. The material was subjected to poor scanning without thermal measurement. The junction is in the end of the pit and the third-order endothermic peak, and has a plurality of melting points in the lower and lower regions. Next, the i-th metal particles VIII and the third metal scorpion 6 ′ are mixed at a mass ratio 186 as a metal filler component. The metal filler component is then mixed with 884 mass. /. And the welding of the Qichuan. 6 mass%, with the example! The same steps to make solder paste. In the same manner as in the case of the example i (4), the obtained paste was subjected to a reflow heat treatment at a peak temperature of 16 〇t under a nitrogen atmosphere to prepare a Cu wafer bonded substrate, and the joint strength at normal temperature and 260 dead heating was measured. The results are shown in Table 7 in Comparative Example 7. Further, a Cu powder (Cu-HWQ 15 μηι, manufactured by Fukuda Metal Foil Co., Ltd.) and a third metal particle were mixed at a mass ratio of 100 to 186 to form a metal filler component. Then, a flux paste was prepared by mixing the metal filler component 88 7 mass% and the flux (β) ι mass % ' in the same manner as in Example 1. In the same manner as in the example (4), the peak temperature was 16 Torr under a nitrogen atmosphere. 〇Reflow heat treatment was performed. • Cu wafer bonded substrate was prepared, and normal temperature and 26 (joint strength at TC heating were measured. The results are shown in Comparative Example 8 of Table 7. According to Examples 28 and 29 and Comparative Example 7, the first metal was used. When the metal filler in which the third metal particles were mixed was used as the particles in place of the second metal particles, it was found that the bonding strength at the system temperature was low. Further, comparing Comparative Example 7 and Comparative Example 8, it was found that the joint strength was low. The value is approximately the same as the joint strength. That is, when the third metal particles are used, it is confirmed that the combination with the second metal particles A and the combination with the Cu powder exhibits low joint strength. 146300.doc -27- 1378841 [ Table i] Reflow heat treatment peak temperature Metal filler composition (mass ratio) Bonding strength (MPa) First metal particle A Second metal particle A Normal temperature 260 〇C Example 1 160 ° C 100 300 15.4 0.35 Example 2 160 ° C 100 186 12.4 0.72 Example 3 160 ° C 100 122 10.2 0.97 Example 4 160 ° C 100 82 3.4 0.78 Example 5 160 ° C 100 54 2.4 0.48 Example '6 180 ° C 100 300 15.9 0.34 Example 7 180 ° C 100 186 13.2 1.1 Example 8 180 ° C 100 122 9.8 1.7 Example 9 180 ° C 100 82 7.7 1.1 Example 10 180 ° C 100 54 3.4 0.8 Comparative Example 1 160 ° C 0 100 38.2 0 Comparative Example 2 180 ° C 0 100 44.3 0 Comparative Example 3 250 〇C Sn-3.0Ag-0.5Cu 26.4 0 [Table 2] Reflow heat treatment peak temperature Metal filler composition (mass ratio) Bonding strength (MPa) First metal particle B Second metal particle B Normal temperature 260 〇 C Example 11 160 ° C 100 300 14 0.5 Example 12 160. 100 186 12.4 0.9 Example 13 160 ° C 100 122 6.7 1.2 Example 14 160 ° C 100 82 3.0 0.9 Example 15 160 ° C 100 54 2.8 1.1 Implementation Example 16 180 ° C 100 300 17.1 0.7 146300.doc -28- 1378841 Example 17 180 ° C 100 186 14.9 1.0 Example 18 180 ° C 100 122 7.4 0.9 Example 19 180 ° C 100 82 4.8 1.0 Example 20 180 °C 100 54 4.5 1.3 [Table 3] Number of occurrences of short circuit between parts and the total number of occurrences Example 21 0/45 0% Comparative Example 4 17/83 20.5%

[Table 4] First metal particles (mass ratio) Second metal particles (mass ratio) Number of floating particles (s) First metal particles A First metal particles B First metal particles C Second metal particles A Example 22 100 0 0 186 7 Example 23 0 100 0 34 Example 24 0 0 100 878

[Table 5] First metal particle (mass ratio) Second metal particle (mass ratio) Adhesion (g · 0 First metal particle A First metal particle B First metal particle D Second metal particle B Example 25 100 0 0 186 148 Example 26 0 100 0 160 Example 27 0 0 100 91 146300.doc •29· 1378841 [Table 6] Reflow heat treatment peak temperature Metal filler composition (mass ratio) Bonding strength (MPa) First metal particle A Cu powder second metal particle A second metal particle B normal temperature 260 〇C Example 28 160 ° C 100 0 186 0 13.5 0.86 Example 29 160 ° C 100 0 0 186 26.8 0.65 Comparative Example 5 160 ° C 0 100 186 0 4.3 0.63 Comparative Example 6 160°C 0 100 0 186 12.4 1.3 [Table 7] Reflow heat treatment peak temperature Metal filler composition (mass ratio) Bonding strength (MPa) First metal particle A Cu powder 3rd metal particle normal temperature 260 〇 C comparison Example 7 160 ° C 100 0 186 3.82 1.74 Comparative Example 8 160 ° C 0 100 186 3.48 1.51 [Industrial Applicability] The metal filler of the present invention and the lead-free solder containing the same can be applied to the subsequent steps for a plurality of times. The purpose of heat treatment (such as the built-in substrate of the part and The electronic device used in the solder material loaded the like, as well as for example a conductive adhesive), and may be mounted to achieve a low temperature. 146300.doc -30-

Claims (1)

7. Patent application scope: A metal filler comprising a mixture of a first metal particle and a second metal particle, the first metal particle containing the element having the highest mass ratio as the main component, Cu' And the alloy particles of the second metal particles are contained in the group of the second metal particles containing Bi 40 to 70% by mass, and the metal selected from the group consisting of Ag Cu, In and Sn, 3〇~6〇% by mass of B i alloy particles; the amount of the second metal particles is 40 to 300 parts by mass based on 1 part by mass of the second metal particles. The metal filler according to claim 1, wherein the second metal particle contains Sn 〇 3. The metal filler according to claim 1 or 2, wherein an average particle diameter of the ith metal particle and the second metal particle are both - The scope. 4. The metal filler according to claim 1 or 2, wherein the first metal particles further contain one or more metals selected from the group consisting of Ag and Bi. 5. The metal filler according to claim 2 or 2, wherein the i-th metal particle comprises Ag 5 to i 5 mass%, Bi 2 to 8 mass%, cu 49 to 8 i mass%, mass... 0/〇, and Sn 10 to 20 mass 〇 / 〇, the first metal particles have at least one heat peak observed in the range of 230 to WC under differential scanning calorimetry (Dsc), and observed in the range of ~53 (TC range) At least one endothermic peak. 6. A materialless agent containing a metal filler as claimed in claim 2 or 2. 7. A connecting structure having a first <f sub-part, a second electronic part, 146300.doc 1378841 And bonding the soldering portion to the electronic component, and the flux bonding portion is formed by reflow heat treatment. The flux bonding between the component and the second electronic component is performed by placing the lead-free soldering agent according to claim 6 into the component mounting substrate. And having a substrate and a connection structure as claimed in claim 7 mounted on the substrate. I46300.doc