JP5895344B2 - Method for producing solder powder and method for producing solder paste using solder powder produced by this method - Google Patents
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Description
本発明は、ファインピッチ用鉛フリーのハンダ粉末の製造方法及びこの方法により製造されたハンダ粉末を用いてハンダ用ペーストを製造する方法に関する。更に詳しくは、平均粒径が５μｍ以下の微細なＳｎ系ハンダ粉末の製造方法及びこの方法により製造されたハンダ粉末を用いてハンダ用ペーストを製造する方法に関するものである。 The present invention relates to a method for producing a lead-free solder powder for fine pitch and a method for producing a solder paste using the solder powder produced by this method. More specifically, the present invention relates to a method for producing a fine Sn-based solder powder having an average particle size of 5 μm or less and a method for producing a solder paste using the solder powder produced by this method.
電子部品の接合に用いられるハンダは環境の面から鉛フリー化が進められ、現在では、錫を主成分としたハンダ粉末が採用されている。ハンダ粉末のような微細な金属粉末を得る方法としては、ガスアトマイズ法や回転ディスク法等のアトマイズ法の他に、メルトスピニング法、回転電極法、機械的プロセス、化学的プロセス等が知られている。ガスアトマイズ法は、誘導炉やガス炉で金属を溶融した後、タンディッシュの底のノズルから溶融金属を流下させ、その周囲より高圧ガスを吹き付けて粉化する方法である。また回転ディスク法は、遠心力アトマイズ法とも呼ばれ、溶融した金属を高速で回転するディスク上に落下させて、接線方向に剪断力を加えて破断して微細粉を作る方法である。 Solder used for joining electronic parts has been made lead-free from the viewpoint of the environment, and at present, solder powder mainly composed of tin is used. As a method for obtaining a fine metal powder such as a solder powder, in addition to an atomizing method such as a gas atomizing method or a rotating disk method, a melt spinning method, a rotating electrode method, a mechanical process, a chemical process, or the like is known. . The gas atomization method is a method in which after melting a metal in an induction furnace or a gas furnace, the molten metal is caused to flow down from a nozzle at the bottom of the tundish, and high pressure gas is sprayed from the surrounding area to pulverize. The rotating disk method is also called a centrifugal force atomizing method, and is a method in which molten metal is dropped on a rotating disk at high speed, and a shearing force is applied in a tangential direction to break and make a fine powder.
一方、電子部品の微細化とともに接合部品のファインピッチ化も進んでおり、より微細な粒径のハンダ粉末が求められているため、こうしたファインピッチ化に向けた技術の改良も盛んに行われている。例えば、ガスアトマイズ法を改良した技術として、ガスを巻き込ませた状態の金属溶湯をノズルから噴出させ、このノズルの周囲から高圧ガスを吹き付ける金属微粉末の製造方法が開示されている（例えば、特許文献１参照。）。この特許文献１に記載の方法では、溶湯がノズルを通過する際にガスを巻き込ませることによって、ノズルから出湯した時点で溶湯がすでに分断され、より小さな粉末を製造することができる。 On the other hand, the fine pitch of joining parts is progressing along with the miniaturization of electronic parts, and there is a demand for solder powder with a finer particle size. Therefore, the technology for fine pitch is being actively improved. Yes. For example, as a technique for improving the gas atomization method, a method for producing a metal fine powder is disclosed in which a molten metal in a gas state is ejected from a nozzle and a high-pressure gas is blown from the periphery of the nozzle (for example, a patent document) 1). In the method described in Patent Document 1, by introducing gas when the molten metal passes through the nozzle, the molten metal is already divided when the molten metal is discharged from the nozzle, and a smaller powder can be manufactured.
また、回転ディスク法を改良した技術として、回転体に金属微粉末サイズ調整手段としてのメッシュを配し、このメッシュを通して溶融金属を飛散させる金属微粉末の製法が開示されている（例えば、特許文献２参照。）。この特許文献２に記載の方法では、従来の回転ディスク法に比べて微細な金属微粉末を効率良く生成できる。 Further, as an improved technique of the rotating disk method, a metal fine powder manufacturing method in which a mesh as metal fine powder size adjusting means is arranged on a rotating body and molten metal is scattered through the mesh is disclosed (for example, Patent Documents). 2). In the method described in Patent Document 2, fine metal fine powder can be efficiently generated as compared with the conventional rotating disk method.
更に、化学的プロセスを用いた技術として、本出願人は、中心核及び中心核を被包する被覆層で構成される構造を有する平均粒径５μｍ以下のハンダ粉末であって、中心核が錫よりも貴な金属或いは水素過電圧が低い金属である銀、銅、ビスマス、ゲルマニウム、ニッケル又はインジウムからなり、被覆層が錫からなることを特徴とするハンダ粉末を開示している（例えば、特許文献３参照。）。この特許文献３に示されるハンダ粉末では、錫よりも貴な金属或いは水素過電圧が低い金属とした中心核を構成する金属元素により、ハンダ合金の機械的強度が向上する。溶媒に中心核を構成する金属元素を含む化合物と被覆層を構成する金属元素を含む化合物及び分散剤をそれぞれ添加して混合することにより溶解液を調製し、この調製した溶解液に還元剤水溶液を添加して混合することにより、還元反応を生じさせ、錫よりも貴な金属或いは水素過電圧が低い金属を還元させて中心核を形成し、続いて錫が還元させて、錫を中心核の表面に析出させることで、上記構造の金属粉末を形成している。 Further, as a technique using a chemical process, the applicant of the present application is a solder powder having an average particle diameter of 5 μm or less having a structure composed of a central core and a coating layer encapsulating the central core, the central core being tin. Disclosed is a solder powder characterized in that it is made of silver, copper, bismuth, germanium, nickel, or indium, which is a noble metal or a metal having a lower hydrogen overvoltage, and the coating layer is made of tin (for example, patent document) 3). In the solder powder disclosed in Patent Document 3, the mechanical strength of the solder alloy is improved by the metal element constituting the central core made of a noble metal or a metal having a lower hydrogen overvoltage than tin. A solvent is prepared by adding a compound containing a metal element constituting the central core to the solvent, a compound containing the metal element constituting the coating layer, and a dispersing agent, and mixing them. An aqueous reducing agent solution is added to the prepared solution. Is added and mixed to cause a reduction reaction, and a noble metal or a metal having a lower hydrogen overvoltage than tin is reduced to form a central nucleus, and then tin is reduced, so that tin becomes a central nucleus. By depositing on the surface, the metal powder having the above structure is formed.
しかしながら、上記従来の特許文献１，２に示された、いわゆるアトマイズ法により微細な粉末を得るためには、この方法によって得られた金属粉末を更に分級して、ファインピッチ化に対応する５μｍ以下の微細なものを採取する必要がある。このため、歩留まりが非常に悪くなる。一方、７μｍ程度の粉末であれば、この方法でも歩留まりは良くなるものの、この程度の粒径のものでは、近年のファインピッチ化には十分に対応できない。 However, in order to obtain a fine powder by the so-called atomization method shown in the above-mentioned conventional Patent Documents 1 and 2, the metal powder obtained by this method is further classified to 5 μm or less corresponding to fine pitch formation. It is necessary to collect the fine thing. For this reason, a yield will become very bad. On the other hand, if the powder is about 7 μm, the yield is improved even with this method, but a particle having this particle size cannot sufficiently cope with the recent fine pitch.
また、上記特許文献３に示されたハンダ粉末のように、錫とは異なる種類の金属元素が核になっている場合、溶食反応の後に拡散が起こるため、ハンダバンプ形成の溶融時に時間がかかるため、濡れ性が悪いという問題を有していた。 In addition, as in the case of the solder powder shown in Patent Document 3, when a metal element of a different type from tin is used as a nucleus, diffusion occurs after the erosion reaction, so it takes time to melt the solder bump formation. For this reason, it has a problem of poor wettability.
本発明の第１の目的は、ファインピッチ化を実現するハンダ用ペーストに好適な微細なハンダ粉末であって、リフロー時の溶融拡散性が良く、ハンダバンプ形成時の組成制御が容易であり、濡れ性に優れた、ハンダ粉末を製造する方法を提供することにある。本発明の第２の目的は、このハンダ粉末を用いてハンダ用ペーストを製造する方法を提供することにある。 The first object of the present invention is a fine solder powder suitable for a solder paste that realizes fine pitch, has good melt diffusibility during reflow, easy composition control during solder bump formation, and wetness An object of the present invention is to provide a method for producing solder powder having excellent properties. The second object of the present invention is to provide a method for producing a solder paste using this solder powder.
本発明の第１の観点は、溶媒に、銀、銅、インジウム又は金の金属元素を含む化合物と錫元素を含む化合物と分散剤とをそれぞれ添加して混合することにより、ｐＨ０〜２．０の範囲にある溶解液を調製する工程と、前記溶解液と同程度のｐＨを有する還元剤水溶液を前記溶解液に添加混合することにより、前記溶解液中の銀、銅、インジウム又は金の金属イオンが還元されて形成された金属元素核とこの金属元素核を被覆する錫からなる被覆層で構成された金属粉末が分散した分散液を得る工程と、前記分散液を固液分離して固形分を回収する工程と、前記回収した固形分に、沸点が１００℃以上の高沸点溶媒を加えて分散させ、不活性ガス雰囲気下、銀を用いたとき、１００℃〜１２０℃で２０分間〜１時間加熱し、銅を用いたとき、７０℃〜１００℃で２０分間〜１時間加熱し、インジウムを用いたとき、６０℃〜８０℃で２０分間〜１時間加熱し、金を用いたとき、１４０〜１６０℃で２０分間〜１時間加熱し、この加熱処理を施すことにより、前記金属元素核とこの金属元素核と接触している前記錫被覆層の一部が反応して、前記金属元素核とこの金属元素核の外周を被覆する前記金属元素と錫との金属間化合物層の２層構造からなる中心核が形成され、この中心核を錫からなる被覆層で被覆した平均粒径５μｍ以下のハンダ粉末を得る工程と、を含むハンダ粉末の製造方法である。 According to the first aspect of the present invention, a solvent containing a silver, copper, indium or gold metal element compound, a tin element compound and a dispersant are added to and mixed with the solvent, respectively, to adjust the pH to 0 to 2.0. The step of preparing a solution in the range of the above, and adding and mixing a reducing agent aqueous solution having the same pH as the solution into the solution, silver, copper, indium or gold metal in the solution A step of obtaining a dispersion in which metal powder composed of a metal element nucleus formed by reduction of ions and a coating layer made of tin covering the metal element nucleus is dispersed; A step of recovering the component, and adding the high-boiling solvent having a boiling point of 100 ° C. or higher to the recovered solid component and dispersing the silver in an inert gas atmosphere at 100 ° C. to 120 ° C. for 20 minutes to When heated for 1 hour and using copper, 7 When heated at 20 ° C to 100 ° C for 20 minutes to 1 hour, with indium, heated at 60 ° C to 80 ° C for 20 minutes to 1 hour, and with gold, heated at 140 to 160 ° C for 20 minutes to 1 hour Then, by performing this heat treatment, the metal element nucleus and a part of the tin coating layer in contact with the metal element nucleus react to coat the outer periphery of the metal element nucleus and the metal element nucleus. Forming a central core having a two-layer structure of an intermetallic compound layer of the metal element and tin, and obtaining a solder powder having an average particle diameter of 5 μm or less in which the central core is covered with a coating layer made of tin. It is a manufacturing method of solder powder.
本発明の第２の観点は、溶媒に、ニッケル又はコバルトの金属元素を含む化合物と分散剤とをそれぞれ添加して混合することにより、ｐＨ０〜２．０の範囲にある溶解液を調製する工程と、前記溶解液と同程度のｐＨを有する還元剤水溶液を前記溶解液に添加混合することにより、前記溶解液中のニッケル又はコバルトの金属イオンが還元されて形成された金属元素核が分散した第１分散液を得る工程と、前記第１分散液に錫元素を含む化合物を添加して混合することにより、前記金属元素核とこの金属元素核を被覆する錫からなる被覆層で構成された金属粉末が分散した第２分散液を得る工程と、前記第２分散液を固液分離して固形分を回収する工程と、前記回収した固形分に、沸点が１００℃以上の高沸点溶媒を加えて分散させ、不活性ガス雰囲気下、ニッケルを用いたとき、１００℃〜１３０℃で２０分間〜１時間加熱し、コバルトを用いたとき、９０〜１１０℃で２０分間〜１時間加熱し、この加熱処理を施すことにより、前記金属元素核とこの金属元素核と接触している前記錫被覆層の一部が反応して、前記金属元素核とこの金属元素核の外周を被覆する前記金属元素と錫との金属間化合物層の２層構造からなる中心核が形成され、この中心核を錫からなる被覆層で被覆した平均粒径５μｍ以下のハンダ粉末を得る工程と、を含むハンダ粉末の製造方法である。 The second aspect of the present invention is a step of preparing a solution in the range of pH 0 to 2.0 by adding and mixing a compound containing a nickel or cobalt metal element and a dispersant to a solvent. Then, by adding and mixing a reducing agent aqueous solution having a pH comparable to that of the solution into the solution, metal element nuclei formed by reduction of nickel or cobalt metal ions in the solution were dispersed. A step of obtaining a first dispersion and a coating layer made of tin covering the metal element nucleus by adding and mixing a compound containing tin element to the first dispersion and mixing. A step of obtaining a second dispersion in which metal powder is dispersed, a step of solid-liquid separation of the second dispersion to recover a solid content, and a high boiling point solvent having a boiling point of 100 ° C. or higher in the recovered solid content. In addition, disperse and inert When nickel is used in a glass atmosphere, heating is performed at 100 to 130 ° C. for 20 minutes to 1 hour, and when cobalt is used, heating is performed at 90 to 110 ° C. for 20 minutes to 1 hour, and this heat treatment is performed. A part of the tin coating layer in contact with the metal element nucleus reacts with the metal element nucleus and the metal between the metal element nucleus and the metal covering the outer periphery of the metal element nucleus and the metal. And a step of obtaining a solder powder having an average particle size of 5 μm or less in which a central core having a two-layer structure of compound layers is formed and the central core is coated with a coating layer made of tin.
本発明の第３の観点は、前記中心核が銀、銅、インジウム又は金からなる金属元素核と、この金属元素核の外周に前記金属元素と錫との金属間化合物層を有する２層構造からなり、前記被覆層が錫からなる本発明の第１の観点のハンダ粉末の製造方法である。 According to a third aspect of the present invention, there is provided a two-layer structure in which the central nucleus includes a metal element nucleus composed of silver, copper, indium or gold, and an intermetallic compound layer of the metal element and tin on the outer periphery of the metal element nucleus. made, the coating layer is a manufacturing method of the first aspect of the solder powder of the present invention that Do tin.
本発明の第４の観点は、前記中心核がニッケル又はコバルトからなる金属元素核と、この金属元素核の外周に前記金属元素と錫との金属間化合物層を有する２層構造からなり、前記被覆層が錫からなる本発明の第２の観点のハンダ粉末の製造方法である。
本発明の第５の観点は、第３の観点に基づく発明であって、銀を含むとき銀の含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜１０質量％であり、銅を含むとき銅の含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜２．０質量％であり、インジウムを含むときインジウムの含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜１０質量％であり、金を含むとき金の含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であるハンダ粉末の製造方法である。
本発明の第６の観点は、第４の観点に基づく発明であって、ニッケルを含むときニッケルの含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であり、コバルトを含むときコバルトの含有割合が前記ハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であるハンダ粉末の製造方法である。
本発明の第７の観点は、第３ないし第６のいずれかの観点の方法で製造されたハンダ粉末とハンダ用フラックスを混合してペースト化することによりハンダ用ペーストを製造する方法である。
本発明の第８の観点は、第７の観点に基づく発明であって、電子部品の実装用にハンダ用ペーストを製造するハンダ用ペーストの製造方法である。
According to a fourth aspect of the present invention, there is provided a two-layer structure having a metal element nucleus in which the central nucleus is made of nickel or cobalt and an intermetallic compound layer of the metal element and tin on the outer periphery of the metal element nucleus, coating layer is a method for producing a solder powder of the second aspect of the present invention that Do tin.
5th viewpoint of this invention is invention based on 3rd viewpoint, Comprising: When silver is included, the content rate of silver is 0.1-10 mass% with respect to 100 mass% of the whole quantity of the said solder powder. When copper is included, the copper content is 0.1 to 2.0% by mass with respect to 100% by mass of the total amount of the solder powder, and when indium is included, the content of indium is 100% of the total amount of the solder powder. 0.1 to 10% by mass with respect to mass%, and when gold is included, the content of gold is 0.1 to 1.0% by mass with respect to 100% by mass of the total amount of the solder powder . It is a manufacturing method .
6th viewpoint of this invention is invention based on 4th viewpoint, Comprising: When nickel is included, the content rate of nickel is 0.1-1.0 mass% with respect to 100 mass% of the whole quantity of the said solder powder. In the method for producing solder powder , when cobalt is contained, the content ratio of cobalt is 0.1 to 1.0 mass% with respect to 100 mass% of the total amount of the solder powder.
A seventh aspect of the present invention, a method of manufacturing a by rehabilitation Sunda paste to paste by mixing the produced solder powder and solder flux in any aspect of the method of the third to sixth It is.
An eighth aspect of the present invention is an invention based on the seventh aspect, and is a solder paste manufacturing method for manufacturing a solder paste for mounting electronic components.
本発明の第１の観点の方法及び第２の観点の方法により製造されたハンダ粉末は、中心核と中心核を被覆する被覆層で構成される平均粒径５μｍ以下のハンダ粉末において、中心核が銀、銅、ニッケル、インジウム、コバルト又は金からなる金属元素核と、この金属元素核の外周に金属元素と錫との金属間化合物層を有する２層構造からなり、被覆層が錫からなる。このように、本発明のハンダ粉末では、中心核を金属元素核と、この金属元素核の外周に金属元素と錫との金属間化合物層を有する２層構造としているため、中心核が金属元素のみで構成された従来のハンダ粉末に比べ、リフロー時の溶融拡散性が良く、ハンダバンプ形成時の組成制御が容易であり、濡れ性に優れる。また、平均粒径５μｍ以下と微細な粉末であるため、この粉末を原料としたハンダ用ペーストを基板等に印刷する際に、ファインピッチパターンで印刷できる。 The solder powder produced by the method according to the first aspect and the method according to the second aspect of the present invention is a solder powder having an average particle size of 5 μm or less composed of a central core and a coating layer covering the central core. but it becomes silver, copper, nickel, indium, a metal element nuclei consisting of cobalt or gold, a two-layer structure having an intermetallic compound layer of a metal element and tin on the outer periphery of the metal element core, the coating layer is made of tin . As described above, in the solder powder of the present invention, the central nucleus has a metal element nucleus and a two-layer structure having an intermetallic compound layer of a metal element and tin on the outer periphery of the metal element nucleus. Compared to the conventional solder powder composed only of the above, it has good melt diffusibility during reflow, easy composition control during solder bump formation, and excellent wettability. Further, since it is a fine powder having an average particle size of 5 μm or less, it can be printed with a fine pitch pattern when a solder paste made from this powder is printed on a substrate or the like.
本発明の第７の観点の方法で製造されたハンダ用ペーストは、上記本発明のハンダ粉末を用いて得られる。そのため、このハンダ用ペーストは、リフロー時の溶融が速く、濡れ性が非常に良いため、ハンダバンプ形成時に溶融したペーストが微細な球状になって飛散する、いわゆるソルダボールの発生を大幅に抑制することができる。また、形成後のハンダバンプにおける組成をより均一にできるため、溶け残りが生じないハンダバンプを形成することができる。更にハンダ粉末は５μｍ以下と微細であるため、このハンダ用ペーストを用いれば、基板等にファインピッチパターンで印刷でき、より微細な電子部品を実装できる。 The solder paste manufactured by the method of the seventh aspect of the present invention is obtained using the solder powder of the present invention. For this reason, this solder paste is rapidly melted at the time of reflow and has very good wettability, so that the paste melted at the time of solder bump formation becomes a fine sphere and scatters so-called solder balls are greatly suppressed. Can do. Further, since the composition of the solder bumps after formation can be made more uniform, it is possible to form solder bumps that do not cause unmelted residue. Furthermore, since the solder powder is as fine as 5 μm or less, if this solder paste is used, it can be printed on a substrate or the like with a fine pitch pattern, and a finer electronic component can be mounted.
次に本発明を実施するための形態を図面に基づいて説明する。 Next, an embodiment for carrying out the present invention will be described with reference to the drawings.
本発明のハンダ粉末は、図１に示すように、中心核１１と、この中心核を被覆する被覆層１２により構成され、平均粒径が５μｍ以下、好ましくは０．１〜５μｍの粉末である。ハンダ粉末の平均粒径を５μｍ以下に限定したのは、５μｍを越えるとハンダ用ペーストを基板等にファインピッチパターンで印刷できず、微細な電子部品をハンダ用ペーストにより実装できないからである。なお、本明細書において、粉末の平均粒径とは、レーザー回折散乱法を用いた粒度分布測定装置（堀場製作所社製、レーザー回折／散乱式粒子径分布測定装置ＬＡ−９５０）にて測定した体積累積中位径(Ｍｅｄｉａｎ径、Ｄ50)をいう。そして、本発明のハンダ粉末の特徴ある構成は、中心核が銀、銅、ニッケル、インジウム、コバルト又は金からなる金属元素核と、この金属元素核の外周に金属元素と錫との金属間化合物層を有する２層構造からなり、被覆層が錫からなるところにある。
As shown in FIG. 1, the solder powder of the present invention comprises a
このように、本発明のハンダ粉末は、中心核を金属元素核と、この金属元素核の外周に金属元素と錫との金属間化合物層を有する２層構造としているため、中心核が金属元素のみで構成された従来のハンダ粉末に比べ、リフロー時の溶融拡散性が良く、ハンダバンプ形成時の組成制御が容易であり、濡れ性に優れる。また、平均粒径５μｍ以下と微細な粉末であるため、この粉末を原料としたハンダ用ペーストを基板等に印刷する際に、ファインピッチパターンで印刷できる。 Thus, the solder powder of the present invention has a two-layer structure in which the central nucleus has a metal element nucleus and an intermetallic compound layer of a metal element and tin on the outer periphery of the metal element nucleus. Compared to the conventional solder powder composed only of the above, it has good melt diffusibility during reflow, easy composition control during solder bump formation, and excellent wettability. Further, since it is a fine powder having an average particle size of 5 μm or less, it can be printed with a fine pitch pattern when a solder paste made from this powder is printed on a substrate or the like.
中心核を構成する金属間化合物層としてはＡｇ3Ｓｎ、Ｃｕ6Ｓｎ5、ＣｏＳｎ、Ｃｏ3Ｓｎ2、ＣｏＳｎ2、Ｎｉ3Ｓｎ、Ｎｉ3Ｓｎ2、Ｎｉ3Ｓｎ4、Ｉｎ3Ｓｎ、ＩｎＳｎ4、ＡｕＳｎ、ＡｕＳｎ2、ＡｕＳｎ4が挙げられる。 As the intermetallic compound layer constituting the central core, Ag 3 Sn, Cu 6 Sn 5 , CoSn, Co 3 Sn 2 , CoSn 2 , Ni 3 Sn, Ni 3 Sn 2 , Ni 3 Sn 4 , In 3 Sn, InSn 4 , AuSn, AuSn 2 , and AuSn 4 .
ハンダ粉末が銀を含むとき、即ちハンダ粉末の中心核が銀元素核と、この銀元素核の外周に銀と錫との金属間化合物層を有する２層構造から構成される場合、銀の含有割合がハンダ粉末の全体量１００質量％に対して０．１〜１０質量％であることが好ましい。 When the solder powder contains silver, that is, when the solder powder has a two-layer structure in which the central core of the solder powder has a silver element nucleus and an intermetallic compound layer of silver and tin around the silver element nucleus, the inclusion of silver The ratio is preferably 0.1 to 10% by mass with respect to 100% by mass of the total amount of solder powder.
また、銅を含むとき銅の含有割合がハンダ粉末の全体量１００質量％に対して０．１〜２．０質量％であることが好ましい。ニッケルを含むときニッケルの含有割合がハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であることが好ましい。インジウムを含むときインジウムの含有割合がハンダ粉末の全体量１００質量％に対して０．１〜１０質量％であることが好ましい。コバルトを含むときコバルトの含有割合がハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であることが好ましい。金を含むとき金の含有割合がハンダ粉末の全体量１００質量％に対して０．１〜１．０質量％であることが好ましい。ここで、上記元素の含有割合をそれぞれ上記範囲に限定したのは、共晶点から組成がずれるのを防止してハンダ粉末の融点を低くするとともに、形成したハンダバンプにおけるハンダ合金の電気抵抗の増加を抑え、機械的強度を向上させるためである。 Moreover, it is preferable that the content rate of copper is 0.1-2.0 mass% with respect to 100 mass% of whole quantity of solder powder, when copper is included. When nickel is included, the nickel content is preferably 0.1 to 1.0% by mass with respect to 100% by mass of the total amount of solder powder. When indium is contained, the content of indium is preferably 0.1 to 10% by mass with respect to 100% by mass of the total amount of solder powder. When cobalt is contained, the content ratio of cobalt is preferably 0.1 to 1.0% by mass with respect to 100% by mass of the total amount of solder powder. When gold is contained, the content of gold is preferably 0.1 to 1.0% by mass with respect to 100% by mass of the total amount of solder powder. Here, the content ratios of the above elements are limited to the above ranges, respectively, to prevent the composition from deviating from the eutectic point and to lower the melting point of the solder powder, and to increase the electrical resistance of the solder alloy in the formed solder bump. This is to suppress mechanical strength and improve mechanical strength.
続いて、上記本発明のハンダ粉末を製造する方法について説明する。銀、銅、インジウム又は金を中心核とする場合には、先ず、溶媒に、中心核の金属元素核並びに金属間化合物層を構成する金属元素、即ち銀、銅、インジウム又は金を含む化合物と、中心核の金属間化合物層や被覆層を構成する錫元素を含む化合物及び分散剤とをそれぞれ添加して混合することにより、溶解液を調製する。溶解液中における金属元素を含む化合物と、錫元素を含む化合物の含有割合は、金属粉末製造後に、各金属元素の含有割合が上記範囲になるように調整する。 Subsequently, a method for producing the solder powder of the present invention will be described. In the case of using silver, copper, indium or gold as a central nucleus, first, in a solvent, a metal element nucleus of the central nucleus and a metal element constituting the intermetallic compound layer, that is, a compound containing silver, copper, indium or gold A solution is prepared by adding and mixing a compound containing a tin element constituting the intermetallic compound layer of the central core and the coating layer, and a dispersant. The content ratio of the compound containing the metal element and the compound containing the tin element in the solution is adjusted so that the content ratio of each metal element is within the above range after the metal powder is produced.
溶媒としては、水、アルコール、エーテル、ケトン、エステル等が挙げられる。中心核を銀と錫との金属間化合物とする場合、使用される銀化合物としては、塩化銀又は硝酸銀等が挙げられる。銅化合物としては、塩化銅(II)、硫酸銅(II)又は酢酸銅等が挙げられる。インジウム化合物としては、塩化インジウム、硝酸インジウム又は硫酸インジウム等が挙げられる。金化合物としては、テトラクロロ金（III）酸等が挙げられる。一方、錫元素を含む化合物としては、塩化錫(II)、硫化錫(II)、酢酸錫(II)、シュウ酸錫(II)等が挙げられる。分散剤としては、セルロース系、ビニル系、多価アルコール等が挙げられ、その他にゼラチン、カゼイン等を用いることができる。調製した溶解液はｐＨ調整する。溶解液のｐＨは、生成したハンダ粉末の再溶解等を考慮して、０〜２．０の範囲に調整するのが好ましい。なお、溶媒に上記金属元素を含む化合物と錫元素を含む化合物をそれぞれ添加して溶解させた後、錯化剤を加えて、各金属元素を錯体化した後に、分散剤を添加しても良い。錯化剤を加えることでｐＨがアルカリ側でも金属イオンが沈殿せず、広い範囲での合成が可能となる。錯化剤としては、コハク酸、酒石酸、グリコール酸、乳酸、フタル酸、リンゴ酸、クエン酸、シュウ酸、エチレンジアミン四酢酸、イミノ二酢酸、ニトリロ三酢酸又はその塩等が挙げられる。 Examples of the solvent include water, alcohol, ether, ketone, ester and the like. When the central core is an intermetallic compound of silver and tin, examples of the silver compound used include silver chloride and silver nitrate. Examples of the copper compound include copper (II) chloride, copper (II) sulfate, and copper acetate. Examples of indium compounds include indium chloride, indium nitrate, and indium sulfate. Examples of the gold compound include tetrachloroauric (III) acid. On the other hand, examples of the compound containing tin element include tin (II) chloride, tin (II) sulfide, tin (II) acetate, and tin (II) oxalate. Examples of the dispersant include cellulose-based, vinyl-based, and polyhydric alcohols. In addition, gelatin, casein, and the like can be used. The pH of the prepared solution is adjusted. The pH of the solution is preferably adjusted to a range of 0 to 2.0 in consideration of redissolution of the generated solder powder. In addition, after adding and dissolving each of the compound containing the metal element and the compound containing tin element in the solvent, a complexing agent may be added to complex each metal element, and then a dispersant may be added. . By adding a complexing agent, metal ions do not precipitate even when the pH is alkaline, and synthesis in a wide range is possible. Examples of the complexing agent include succinic acid, tartaric acid, glycolic acid, lactic acid, phthalic acid, malic acid, citric acid, oxalic acid, ethylenediaminetetraacetic acid, iminodiacetic acid, nitrilotriacetic acid, and salts thereof.
次に、還元剤を溶解した水溶液を調製し、この水溶液のｐＨを、上記調製した溶解液と同程度に調整する。還元剤としては、テトラヒドロホウ酸ナトリウム、ジメチルアミンボラン等のホウ素水素化物、ヒドラジン等の窒素化合物、三価のチタンイオンや２価のクロムイオン等の金属イオン等が挙げられる。 Next, an aqueous solution in which the reducing agent is dissolved is prepared, and the pH of the aqueous solution is adjusted to the same level as that of the prepared solution. Examples of the reducing agent include boron hydrides such as sodium tetrahydroborate and dimethylamine borane, nitrogen compounds such as hydrazine, metal ions such as trivalent titanium ions and divalent chromium ions, and the like.
次に、上記溶解液に還元剤水溶液を添加して混合することにより、溶解液中の各金属イオンが還元され、液中に金属粉末が分散した分散液が得られる。この還元反応では、先ず、錫よりも貴な金属又は水素過電圧が低い金属が還元されて中心核が形成される。続いて錫が還元され、形成された中心核の表面に錫が析出することにより、中心核とこの中心核を被覆する錫で構成された、平均粒径５μｍ以下の金属粉末が形成される。 Next, by adding a reducing agent aqueous solution to the solution and mixing, each metal ion in the solution is reduced, and a dispersion in which metal powder is dispersed in the solution is obtained. In this reduction reaction, first, a noble metal or a metal having a lower hydrogen overvoltage than tin is reduced to form a central nucleus. Subsequently, tin is reduced, and tin is deposited on the surface of the formed central core, thereby forming a metal powder having an average particle diameter of 5 μm or less, which is composed of the central core and tin covering the central core.
ニッケル又はコバルトを中心核とする場合には、先ず、溶媒に中心核の金属間化合物を構成する金属元素を含む化合物、即ちニッケル又はコバルトを含む化合物と分散剤とをそれぞれ添加して混合することにより溶解液を調製する。溶媒及び分散剤には上記と同等のものを使用できる。使用されるニッケル化合物としては、塩化ニッケル(II)、硫酸ニッケル(II)六水和物又は硝酸ニッケル(II)六水和物等が挙げられる。コバルト化合物としては、塩化コバルト(II)又は硝酸コバルト(II)又は硫酸コバルト(II)等が挙げられる。調製した溶解液はｐＨ調整する。溶解液のｐＨは、生成したハンダ粉末の再溶解等を考慮して、０〜２．０の範囲に調整するのが好ましい。 When the central core of nickel or cobalt, first, compounds containing metal elements constituting the intermetallic compound of the central core in a solvent, i.e., mixing by adding respectively with a compound containing nickel or cobalt dispersing agent and the Prepare the lysate. As the solvent and the dispersant, the same ones as described above can be used. Examples of the nickel compound used include nickel (II) chloride, nickel (II) sulfate hexahydrate, and nickel (II) nitrate hexahydrate. Examples of the cobalt compound include cobalt (II) chloride, cobalt (II) nitrate, and cobalt (II) sulfate. The pH of the prepared solution is adjusted. The pH of the solution is preferably adjusted to a range of 0 to 2.0 in consideration of redissolution of the generated solder powder.
次に、上記溶解液に還元剤水溶液を添加して混合することにより、溶解液中の金属イオンが還元され、液中に金属核が形成される。還元剤には上記と同等のものを使用でき、この水溶液のｐＨは、上記調製した溶解液と同程度に調整される。 Next, by adding a reducing agent aqueous solution to the solution and mixing, the metal ions in the solution are reduced, and metal nuclei are formed in the solution. As the reducing agent, the same one as described above can be used, and the pH of the aqueous solution is adjusted to the same level as the prepared solution.
次に、中心核の金属間化合物や被覆層を構成する錫元素を含む化合物及び分散剤とを上記溶解液と同程度のｐＨに調整し、先ほどの混合液に追加することにより、錫が先ほどの金属核を中心として成長し、中心核とこの中心核を被覆する錫で構成された、平均粒径５μｍ以下の金属粉末が形成される。 Next, by adjusting the intermetallic compound of the central core and the compound containing the tin element constituting the coating layer and the dispersant to the same pH as the above-mentioned solution, and adding to the previous mixture, tin is Thus, a metal powder having an average particle size of 5 μm or less, which is composed of the central core and tin covering the central core, is formed.
このような反応は微細な粒径の粉末が製造し易いという効果がある。溶解液と還元剤水溶液を混合する方法としては、容器内の溶解液に所定の添加速度で還元剤水溶液を滴下し、スターラ等で攪拌する方法や、所定の径を有する反応チューブを用い、この反応チューブ内に両液を所定の流量で注ぎ込み、混合させる方法等が挙げられる。 Such a reaction has an effect that it is easy to produce a fine particle size powder. As a method of mixing the dissolving solution and the reducing agent aqueous solution, the reducing agent aqueous solution is dropped into the dissolving solution in the container at a predetermined addition rate and stirred with a stirrer or a reaction tube having a predetermined diameter. Examples include a method of pouring both solutions into a reaction tube at a predetermined flow rate and mixing them.
次いで、この分散液を、デカンテーション等によって固液分離し、回収した固形分を水又はｐＨを０．５〜２に調整した塩酸水溶液、硝酸水溶液、硫酸水溶液、或いはメタノール、エタノール、アセトン等で洗浄する。洗浄後は、再度固液分離して固形分を回収する。洗浄から固液分離までの工程を、好ましくは２〜５回繰り返す。 Then, this dispersion is subjected to solid-liquid separation by decantation or the like, and the collected solid content is water or a hydrochloric acid aqueous solution, a nitric acid aqueous solution, a sulfuric acid aqueous solution, or methanol, ethanol, acetone, etc., adjusted to a pH of 0.5-2. Wash. After washing, the solid content is recovered by solid-liquid separation again. The steps from washing to solid-liquid separation are preferably repeated 2 to 5 times.
次に、回収した固形分に、沸点が１００℃以上の高沸点溶媒を加えて分散させ、不活性ガス雰囲気下、所定の温度で加熱する。この加熱処理を施すことにより、上記還元反応で形成された金属粉末の金属元素からなる中心核と、中心核と接触している被覆層の一部が反応して、金属元素核と、この金属元素核の外周を被覆する金属元素と錫との金属間化合物層の２層構造からなる中心核が形成され、この中心核を錫からなる被覆層で被覆した構成となる。 Next, a high-boiling solvent having a boiling point of 100 ° C. or higher is added to the recovered solid content and dispersed, and heated at a predetermined temperature in an inert gas atmosphere. By performing this heat treatment, the central core composed of the metal element of the metal powder formed by the above reduction reaction reacts with a part of the coating layer in contact with the central core, and the metal element nucleus and the metal A central nucleus having a two-layer structure of an intermetallic compound layer of a metal element and tin covering the outer periphery of the element nucleus is formed, and the central nucleus is covered with a coating layer made of tin.
使用される高沸点溶媒としてはジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、ヒマシ油等が挙げられる。 Examples of the high boiling point solvent used include diethylene glycol, triethylene glycol, polyethylene glycol, and castor oil.
金属元素に銀を用いたとき、１００℃〜１２０℃で２０分間〜１時間加熱することが好ましく、１１０℃で３０分間加熱することが特に好ましい。また、銅を用いたとき、７０℃〜１００℃で２０分間〜１時間加熱することが好ましく、９０℃で３０分間加熱することが特に好ましい。また、ニッケルを用いたとき、１００℃〜１３０℃で２０分間〜１時間加熱することが好ましく、１２０℃で３０分間加熱することが特に好ましい。また、インジウムを用いたとき、６０℃〜８０℃で２０分間〜１時間加熱することが好ましく、７０℃で３０分間加熱することが特に好ましい。また、コバルトを用いたとき、９０〜１１０℃で２０分間〜１時間加熱することが好ましく、１００℃で３０分間加熱することが特に好ましい。また、金を用いたとき、１４０〜１６０℃で２０分間〜１時間加熱することが好ましく、１５０℃で３０分間加熱することが特に好ましい。 When silver is used as the metal element, it is preferably heated at 100 ° C. to 120 ° C. for 20 minutes to 1 hour, and particularly preferably heated at 110 ° C. for 30 minutes. Moreover, when using copper, it is preferable to heat at 70 to 100 degreeC for 20 minutes to 1 hour, and it is especially preferable to heat at 90 degreeC for 30 minutes. When nickel is used, it is preferably heated at 100 ° C. to 130 ° C. for 20 minutes to 1 hour, particularly preferably heated at 120 ° C. for 30 minutes. When indium is used, it is preferably heated at 60 ° C. to 80 ° C. for 20 minutes to 1 hour, and particularly preferably heated at 70 ° C. for 30 minutes. Moreover, when cobalt is used, it is preferable to heat at 90-110 degreeC for 20 minutes-1 hour, and it is especially preferable to heat at 100 degreeC for 30 minutes. Further, when gold is used, it is preferably heated at 140 to 160 ° C. for 20 minutes to 1 hour, and particularly preferably heated at 150 ° C. for 30 minutes.
なお上記温度未満での加熱、或いは保持時間が短い加熱では、中心核に金属間化合物層が形成されず、また上記温度を越える加熱では、錫被膜の酸化により溶融性が低下する不具合が生じる。なお、必要以上に保持時間が長い加熱を施すと、中心核の全てが金属間化合物になる。 When heating is performed at a temperature lower than the above temperature or when the holding time is short, an intermetallic compound layer is not formed on the central core. When heating is performed at a temperature exceeding the above temperature, the melting property is lowered due to oxidation of the tin coating. When heating is performed for a longer holding time than necessary, all of the central core becomes an intermetallic compound.
加熱後は、再度上記洗浄から固液分離までの工程を、好ましくは２〜５回繰り返した後、回収した固形分を真空乾燥させることにより、本発明のハンダ粉末を得ることができる。 After heating, the steps from washing to solid-liquid separation are preferably repeated 2 to 5 times, and then the collected solid content is vacuum dried to obtain the solder powder of the present invention.
なお、この実施の形態では、金属元素からなる中心核と、この中心核を被覆する錫からなる被覆層から構成された金属粉末の製造に、還元反応による化学的手法を用いたが、中心核の製造には、アトマイズ法のような物理的手法でも可能である。 In this embodiment, a chemical method based on a reduction reaction is used for the production of metal powder composed of a central core made of a metal element and a coating layer made of tin covering the central core. For the production of this, a physical method such as an atomizing method is also possible.
以上の工程により、本発明のハンダ粉末を得ることができる。このハンダ粉末は、ハンダ用フラックスと混合してペースト化して得られるハンダ用ペーストの材料として好適に用いられる。ハンダ用ペーストの調製は、例えばハンダ用フラックスを、好ましくは１０〜３０質量％、更に好ましくは１０〜２５質量％混合してペースト化することにより行われる。ハンダ用フラックスの混合量を１０〜３０質量％とするのは、１０質量％未満ではフラックス不足でペースト化できず、３０質量％を越えるとペースト中のフラックスの含有割合が多すぎて金属の含有割合が少なくなってしまい、ハンダ溶融時に所望のサイズのハンダバンプを得ることができないからである。 Through the above steps, the solder powder of the present invention can be obtained. This solder powder is suitably used as a material for a solder paste obtained by mixing with a solder flux to form a paste. The solder paste is prepared, for example, by mixing a solder flux, preferably 10-30% by mass, more preferably 10-25% by mass, into a paste. The amount of solder flux mixed is set to 10 to 30% by mass. If the amount is less than 10% by mass, the flux cannot be made into a paste due to insufficient flux. If the amount exceeds 30% by mass, the content of the flux in the paste is too high. This is because the ratio decreases, and a solder bump having a desired size cannot be obtained when the solder is melted.
このハンダ用ペーストは、上記本発明のハンダ粉末を材料としているため、溶融性及び濡れ性が非常に良く、ソルダボールが生じにくい点で優れる。また、形成後のハンダバンプにおける組成をより均一できるため、これを用いて形成されるハンダバンプは、溶け残りが生じない点で優れる。更に５μｍ以下の微細なハンダ粉末によって調製されるため、このハンダ用ペーストを用いれば、基板等にファインピッチパターンで印刷でき、高さのバラツキが少ないハンダバンプを形成することができる。そのため、このハンダ用ペーストは、より微細な電子部品の実装に好適に用いることができる。 Since this solder paste is made of the above-described solder powder of the present invention, it is excellent in that it has very good meltability and wettability, and hardly produces solder balls. Further, since the composition of the solder bumps after formation can be made more uniform, the solder bumps formed using this are excellent in that no undissolved residue occurs. Furthermore, since it is prepared with a fine solder powder of 5 μm or less, by using this solder paste, it is possible to print on a substrate or the like with a fine pitch pattern, and to form a solder bump with little height variation. Therefore, this solder paste can be suitably used for mounting finer electronic components.
次に本発明の実施例と参考例を比較例とともに詳しく説明する。以下に示す実施例３及び実施例６は実施例ではなく参考例である。 Next, examples and reference examples of the present invention will be described in detail together with comparative examples. Examples 3 and 6 shown below are reference examples, not examples.
＜実施例１＞
先ず、水５０ｍＬに塩化銅(II)を３．４５×１０-4ｍｏｌ、塩化錫(II)を２．６２×１０-2ｍｏｌ加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を塩酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら ９０℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ｃｕ元素核と、このＣｕ元素核の外周に金属間化合物Ｃｕ6Ｓｎ5層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 1>
First, 3.45 × 10 −4 mol of copper (II) chloride and 2.62 × 10 −2 mol of tin (II) chloride were added to 50 mL of water, and the mixture was stirred for 5 minutes at a rotational speed of 300 rpm using a stirrer. A lysis solution was prepared. After adjusting the pH of this solution to 0.5 with hydrochloric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred for 10 minutes at a rotation speed of 300 rpm. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, and the mixture was heated at 90 ° C. for 30 minutes with stirring at a rotational speed of 300 rpm. After heating, the dispersion was allowed to stand again for 60 minutes to settle the heated metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes was repeated four times. Washing was performed. Finally, this is dried with a vacuum drier to form a Cu element nucleus and a two-layer structure having an intermetallic compound Cu 6 Sn 5 layer on the outer periphery of the Cu element nucleus as a central core and Sn as a coating layer A powder was obtained.
＜実施例２＞
先ず、水５０ｍＬに硫酸銀(I)を４．３６×１０-4ｍｏｌ、硫酸錫(II)を２．５６×１０-2ｍｏｌ加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を硫酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら１１０℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ａｇ元素核と、このＡｇ元素核の外周に金属間化合物Ａｇ3Ｓｎ層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 2>
First, 4.36 × 10 −4 mol of silver (I) sulfate and 2.56 × 10 −2 mol of tin (II) sulfate were added to 50 mL of water, and the mixture was stirred for 5 minutes at a rotation speed of 300 rpm using a stirrer. A lysis solution was prepared. After adjusting the pH of this solution to 0.5 with sulfuric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred at a rotational speed of 300 rpm for 10 minutes. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, followed by heating at 110 ° C. for 30 minutes while stirring at a rotational speed of 300 rpm. After heating, the dispersion was allowed to stand again for 60 minutes to settle the heated metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes was repeated four times. Washing was performed. Finally, this is dried in a vacuum drier to obtain a metal powder having an Ag element nucleus and a two-layer structure having an intermetallic compound Ag 3 Sn layer around the Ag element nucleus as a central core and Sn as a coating layer Got.
＜実施例３＞
先ず、水２５ｍＬに塩化コバルト(II)を１．６０×１０-3ｍｏｌ加え、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、スターラを用いて回転速度３００ｒｐｍにて１０分間攪拌し、溶解させた。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌した。次に、水２５ｍＬに塩化錫(II)を２．５６×１０-2ｍｏｌを加え、塩酸にてｐＨを０．５に調整した溶液を、添加速度５０ｍＬ／ｓｅｃにて溶解液に加えた後、回転速度３００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら１００℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ｃｏ元素核と、このＣｏ元素核の外周に金属間化合物ＣｏＳｎ層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 3>
First, 1.60 × 10 −3 mol of cobalt (II) chloride is added to 25 mL of water, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) is added as a dispersant, and the rotational speed is set to 300 rpm using a stirrer. And stirred for 10 minutes to dissolve. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to the solution at an addition rate of 50 mL / sec, and the mixture was stirred at a rotation rate of 500 rpm for 10 minutes. Next, 2.56 × 10 −2 mol of tin (II) chloride was added to 25 mL of water, and a solution adjusted to pH 0.5 with hydrochloric acid was added to the solution at an addition rate of 50 mL / sec. The mixture was stirred at a rotational speed of 300 rpm for 10 minutes to reduce each metal ion, thereby obtaining a dispersion liquid in which metal powder was dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, followed by heating at 100 ° C. for 30 minutes while stirring at a rotational speed of 300 rpm. After heating, the dispersion was allowed to stand again for 60 minutes to settle the heated metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes was repeated four times. Washing was performed. Finally, this is dried in a vacuum dryer to obtain a metal powder having a Co element nucleus and a two-layer structure having an intermetallic compound CoSn layer on the outer periphery of the Co element nucleus as a central core and Sn as a coating layer. It was.
＜実施例４＞
先ず、水２５ｍＬに塩化ニッケル(II)を５．３４×１０-5ｍｏｌ加え、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、スターラを用いて回転速度３００ｒｐｍにて１０分間攪拌し、溶解させた。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌した。次に、水２５ｍＬに塩化錫(II)を２．６４×１０-2ｍｏｌ加え、塩酸にてｐＨを０．５に調整した溶液を、添加速度５０ｍＬ／ｓｅｃにて溶解液に加えた後、回転速度３００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら１２０℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰り返すことで洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ｎｉ元素核と、このＮｉ元素核の外周に金属間化合物Ｎｉ3Ｓｎ層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 4>
First, 5.34 × 10 −5 mol of nickel (II) chloride is added to 25 mL of water, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) is added as a dispersant, and the rotational speed is set to 300 rpm using a stirrer. And stirred for 10 minutes to dissolve. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to the solution at an addition rate of 50 mL / sec, and the mixture was stirred at a rotation rate of 500 rpm for 10 minutes. Next, 2.64 × 10 −2 mol of tin (II) chloride was added to 25 mL of water, and a solution adjusted to pH 0.5 with hydrochloric acid was added to the solution at an addition rate of 50 mL / sec. Each metal ion was reduced by stirring for 10 minutes at a rotational speed of 300 rpm to obtain a dispersion in which metal powder was dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, and the mixture was heated at 120 ° C. for 30 minutes while stirring at a rotation speed of 300 rpm. After heating, the dispersion is allowed to stand again for 60 minutes to precipitate the heated metal powder, and then the supernatant is discarded, 100 mL of water is added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes is repeated four times. And washed. Finally, this is dried with a vacuum drier to obtain a metal powder having a Ni element nucleus and a two-layer structure having an intermetallic compound Ni 3 Sn layer on the outer periphery of the Ni element nucleus as a central core and Sn as a coating layer. Got.
＜実施例５＞
先ず、水５０ｍＬに塩化インジウム(III)を２．７３×１０-4ｍｏｌ、塩化錫(II)を２．６１×１０-2ｍｏｌ加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を塩酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら７０℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ｉｎ元素核と、このＩｎ元素核の外周に金属間化合物Ｉｎ3Ｓｎ層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 5>
First, 2.73 × 10 −4 mol of indium (III) chloride and 2.61 × 10 −2 mol of tin (II) chloride were added to 50 mL of water, and the mixture was stirred for 5 minutes at a rotational speed of 300 rpm using a stirrer. A lysis solution was prepared. After adjusting the pH of this solution to 0.5 with hydrochloric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred for 10 minutes at a rotation speed of 300 rpm. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, followed by heating at 70 ° C. for 30 minutes while stirring at a rotational speed of 300 rpm. After heating, the dispersion was allowed to stand again for 60 minutes to settle the heated metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes was repeated four times. Washing was performed. Finally, this is dried with a vacuum drier to obtain a metal powder having an In element nucleus and a two-layer structure having an intermetallic compound In 3 Sn layer around the In element nucleus as a central core and Sn as a coating layer. Got.
＜実施例６＞
先ず、水５０ｍＬにテトラクロロ金(III)酸を１．５９×１０-3ｍｏｌ、塩化錫(II)を２．３８×１０-2ｍｏｌ加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を塩酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。その後、エチレングリコール１００ｍＬを加えて分散させ、回転速度３００ｒｐｍにて攪拌しながら１５０℃で３０分加熱を行った。加熱後、再び分散液を６０分間静置して加熱した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ａｕ元素核と、このＡｕ元素核の外周に金属間化合物ＡｕＳｎ層を有する２層構造を中心核、Ｓｎを被覆層とする金属粉末を得た。
<Example 6>
First, 1.59 × 10 −3 mol of tetrachloroauric (III) acid and 2.38 × 10 −2 mol of tin (II) chloride are added to 50 mL of water, and stirred for 5 minutes at a rotation speed of 300 rpm using a stirrer. Then, a solution was prepared. After adjusting the pH of this solution to 0.5 with hydrochloric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred for 10 minutes at a rotation speed of 300 rpm. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Thereafter, 100 mL of ethylene glycol was added and dispersed, followed by heating at 150 ° C. for 30 minutes while stirring at a rotational speed of 300 rpm. After heating, the dispersion was allowed to stand again for 60 minutes to settle the heated metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the operation of stirring at a rotational speed of 300 rpm for 10 minutes was repeated four times. Washing was performed. Finally, this is dried in a vacuum dryer to obtain a metal powder having a Au core layer, a two-layer structure having an intermetallic compound AuSn layer on the outer periphery of the Au core layer, and Sn as a coating layer. It was.
＜比較例１＞
先ず、水５０ｍＬに塩化銅(II)を３．４５×１０-4ｍｏｌ、塩化錫(II)を２．６２×１０-2ｍｏｌ加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を塩酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ｃｕを中心核、Ｓｎを被覆層とする金属粉末を得た。
<Comparative Example 1>
First, 3.45 × 10 −4 mol of copper (II) chloride and 2.62 × 10 −2 mol of tin (II) chloride were added to 50 mL of water, and the mixture was stirred for 5 minutes at a rotational speed of 300 rpm using a stirrer. A lysis solution was prepared. After adjusting the pH of this solution to 0.5 with hydrochloric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred for 10 minutes at a rotation speed of 300 rpm. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid. The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Finally, this was dried with a vacuum dryer to obtain a metal powder having Cu as the core and Sn as the coating layer.
＜比較例２＞
先ず、水５０ｍＬに硫酸銀(I)を４．３６×１０-4ｍｏｌ、硫酸錫(II)を２．５６×１０-2ｍｏｌを加え、スターラを用いて回転速度３００ｒｐｍにて５分間攪拌し、溶解液を調製した。この溶解液を硫酸にてｐＨを０．５に調整した後、分散剤としてポリビニルアルコール５００（平均分子量が５００のポリビニルアルコール）を０．５ｇ加え、更に回転速度３００ｒｐｍにて１０分間攪拌した。次いで、この溶解液にｐＨを０．５に調整した１．５８ｍｏｌ／Ｌの２価クロムイオン水溶液５０ｍＬを、添加速度５０ｍＬ／ｓｅｃにて加え、回転速度５００ｒｐｍにて１０分間攪拌して各金属イオンを還元し、液中に金属粉末が分散する分散液を得た。
この分散液を６０分間静置して生成した金属粉末を沈降させた後、上澄み液を捨て、ここに水１００ｍＬを加えて回転速度３００ｒｐｍにて１０分間攪拌する操作を４回繰返し、洗浄を行った。最後にこれを真空乾燥機にて乾燥することにより、Ａｇを中心核、Ｓｎを被覆層とする金属粉末を得た。
<Comparative Example 2>
First, 4.36 × 10 −4 mol of silver (I) sulfate and 2.56 × 10 −2 mol of tin (II) sulfate were added to 50 mL of water, and the mixture was stirred for 5 minutes at a rotation speed of 300 rpm using a stirrer. A lysate was prepared. After adjusting the pH of this solution to 0.5 with sulfuric acid, 0.5 g of polyvinyl alcohol 500 (polyvinyl alcohol having an average molecular weight of 500) was added as a dispersant, and the mixture was further stirred at a rotational speed of 300 rpm for 10 minutes. Next, 50 mL of a 1.58 mol / L divalent chromium ion aqueous solution whose pH was adjusted to 0.5 was added to this solution at an addition rate of 50 mL / sec and stirred for 10 minutes at a rotational speed of 500 rpm. To obtain a dispersion in which the metal powder is dispersed in the liquid.
The dispersion was allowed to stand for 60 minutes to settle the metal powder, and then the supernatant was discarded, 100 mL of water was added thereto, and the mixture was stirred for 10 minutes at a rotational speed of 300 rpm, and washed four times. It was. Finally, this was dried with a vacuum dryer to obtain a metal powder having Ag as a central core and Sn as a coating layer.
＜比較試験及び評価＞
実施例１〜６及び比較例１，２で得られた金属粉末について、次に述べる方法により、粉末を構成する金属粒子の構造、粉末の平均粒径、組成の分析又は測定を行い、また金属粉末の濡れ性を評価した。これらの結果を以下の表１に示す。また、図２に実施例２で得られた金属粉末のＸＲＤ構造解析データを示す。
<Comparison test and evaluation>
The metal powders obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were analyzed or measured for the structure of the metal particles constituting the powder, the average particle diameter of the powder, and the composition by the method described below. The wettability of the powder was evaluated. These results are shown in Table 1 below. FIG. 2 shows XRD structural analysis data of the metal powder obtained in Example 2.
(1) 構造分析：粉末Ｘ線回折装置（リガク社製：ＲＩＮＴ Ｕｌｔｉｍａ＋／ＰＣ）により構造分析を行った。 (1) Structural analysis: The structural analysis was performed with a powder X-ray diffractometer (manufactured by Rigaku Corporation: RINT Ultimate + / PC).
(2) 平均粒径：レーザー回折散乱法を用いた粒度分布測定装置（堀場製作所社製、レーザー回折／散乱式粒子径分布測定装置ＬＡ−９５０）にて粒径分布を測定し、その体積累積中位径（Ｍｅｄｉａｎ径、Ｄ50）を金属粉末の平均粒径とした。 (2) Average particle size: The particle size distribution is measured with a particle size distribution measuring device (Horiba, Ltd., laser diffraction / scattering particle size distribution measuring device LA-950) using a laser diffraction scattering method, and the volume is accumulated. The median diameter (Median diameter, D 50 ) was defined as the average particle diameter of the metal powder.
(3) 組成：誘導結合プラズマ発光分光分析（Inductively Coupled Plasma - Atomic Emission Spectroscopy：ＩＣＰ−ＡＥＳ）により金属元素含有量を測定した。 (3) Composition: The metal element content was measured by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES).
(4) 濡れ性評価方法はＪＩＳＺ３２８４に記されている「ぬれ効力及びディウエッティング試験」に準じて行った。評価についても同様に濡れ広がり度合いを１〜４に区分した。 (4) The wettability evaluation method was performed according to the “wetting efficacy and dewetting test” described in JISZ3284. Similarly, the degree of wet spread was divided into 1-4.
表１から明らかなように、中心核が金属元素からなる比較例１，２の金属粉末では濡れ広がり度合いが「２」であるのに対し、中心核が金属元素核とこの外周に金属間化合物層を有する２層構造からなる実施例１〜６の金属粉末では濡れ広がり度合いが「１」と、中心核を金属元素核とこの外周に金属間化合物層を有する２層構造とすることで、濡れ性が向上することが確認された。 As is apparent from Table 1, the metal powders of Comparative Examples 1 and 2 in which the central core is made of a metal element have a wet spread degree of “2”, whereas the central core is a metal element core and an intermetallic compound around this core. In the metal powders of Examples 1 to 6 having a two-layer structure having a layer, the degree of wetting and spreading is “1”, and the central core is a two-layer structure having a metal element core and an intermetallic compound layer on the outer periphery. It was confirmed that the wettability was improved.
本発明のハンダ粉末は、ファインピッチ用鉛フリーのハンダ粉末として利用でき、このハンダ粉末を原料として得られるハンダ用ペーストは、微細な電子部品の実装に好適に用いることができる。 The solder powder of the present invention can be used as a lead-free solder powder for fine pitch, and the solder paste obtained using this solder powder as a raw material can be suitably used for mounting fine electronic components.
１０ ハンダ粉末
１１ 中心核
１１ａ 金属元素
１１ｂ 金属間化合物
１２ 被覆層（Ｓｎ）
10
Claims (8)
前記溶解液と同程度のｐＨを有する還元剤水溶液を前記溶解液に添加混合することにより、前記溶解液中の銀、銅、インジウム又は金の金属イオンが還元されて形成された金属元素核とこの金属元素核を被覆する錫からなる被覆層で構成された金属粉末が分散した分散液を得る工程と、
前記分散液を固液分離して固形分を回収する工程と、
前記回収した固形分に、沸点が１００℃以上の高沸点溶媒を加えて分散させ、不活性ガス雰囲気下、銀を用いたとき、１００℃〜１２０℃で２０分間〜１時間加熱し、銅を用いたとき、７０℃〜１００℃で２０分間〜１時間加熱し、インジウムを用いたとき、６０℃〜８０℃で２０分間〜１時間加熱し、金を用いたとき、１４０〜１６０℃で２０分間〜１時間加熱し、この加熱処理を施すことにより、前記金属元素核とこの金属元素核と接触している前記錫被覆層の一部が反応して、前記金属元素核とこの金属元素核の外周を被覆する前記金属元素と錫との金属間化合物層の２層構造からなる中心核が形成され、この中心核を錫からなる被覆層で被覆した平均粒径５μｍ以下のハンダ粉末を得る工程と、を含むハンダ粉末の製造方法。 A solution containing a metal element of silver, copper, indium or gold, a compound containing a tin element, and a dispersant are added to the solvent and mixed to prepare a solution having a pH in the range of 0 to 2.0. Process,
A metal element nucleus formed by reducing a metal ion of silver, copper, indium or gold in the solution by adding and mixing a reducing agent aqueous solution having a pH comparable to that of the solution to the solution. A step of obtaining a dispersion in which a metal powder composed of a coating layer made of tin covering the metal element nucleus is dispersed;
Solid-liquid separation of the dispersion to recover a solid content;
A high boiling point solvent having a boiling point of 100 ° C. or more is added to the recovered solid content and dispersed, and when silver is used in an inert gas atmosphere, the copper is heated at 100 ° C. to 120 ° C. for 20 minutes to 1 hour, When used, it is heated at 70 to 100 ° C. for 20 minutes to 1 hour, when indium is used, it is heated at 60 to 80 ° C. for 20 minutes to 1 hour, and when gold is used, it is heated at 140 to 160 ° C. for 20 minutes. By heating for 1 minute to 1 hour and applying this heat treatment, a part of the tin coating layer in contact with the metal element nucleus and the metal element nucleus reacts, and the metal element nucleus and the metal element nucleus A central core composed of a two-layer structure of the intermetallic compound layer of the metal element and tin covering the outer periphery of the metal is formed, and a solder powder having an average particle size of 5 μm or less is obtained by covering the central core with a coating layer composed of tin. A process for producing solder powder comprising the steps of:
前記溶解液と同程度のｐＨを有する還元剤水溶液を前記溶解液に添加混合することにより、前記溶解液中のニッケル又はコバルトの金属イオンが還元されて形成された金属元素核が分散した第１分散液を得る工程と、
前記第１分散液に錫元素を含む化合物を添加して混合することにより、前記金属元素核とこの金属元素核を被覆する錫からなる被覆層で構成された金属粉末が分散した第２分散液を得る工程と、
前記第２分散液を固液分離して固形分を回収する工程と、
前記回収した固形分に、沸点が１００℃以上の高沸点溶媒を加えて分散させ、不活性ガス雰囲気下、ニッケルを用いたとき、１００℃〜１３０℃で２０分間〜１時間加熱し、コバルトを用いたとき、９０〜１１０℃で２０分間〜１時間加熱し、この加熱処理を施すことにより、前記金属元素核とこの金属元素核と接触している前記錫被覆層の一部が反応して、前記金属元素核とこの金属元素核の外周を被覆する前記金属元素と錫との金属間化合物層の２層構造からなる中心核が形成され、この中心核を錫からなる被覆層で被覆した平均粒径５μｍ以下のハンダ粉末を得る工程と、を含むハンダ粉末の製造方法。 A step of preparing a solution in the range of pH 0 to 2.0 by adding and mixing a compound containing a metal element of nickel or cobalt and a dispersant to the solvent, and
A reducing agent aqueous solution having a pH comparable to that of the dissolving solution is added to and mixed with the dissolving solution, whereby the metal element nuclei formed by reduction of nickel or cobalt metal ions in the dissolving solution are dispersed. Obtaining a dispersion;
A second dispersion liquid in which a metal powder composed of the metal element nucleus and a coating layer made of tin covering the metal element nucleus is dispersed by adding and mixing a compound containing tin element to the first dispersion liquid. Obtaining
Solid-liquid separation of the second dispersion to recover a solid content;
A high boiling point solvent having a boiling point of 100 ° C. or higher is added to the collected solid and dispersed. When nickel is used in an inert gas atmosphere, the cobalt is heated at 100 ° C. to 130 ° C. for 20 minutes to 1 hour, When used, heating is performed at 90 to 110 ° C. for 20 minutes to 1 hour, and by performing this heat treatment, a part of the tin coating layer in contact with the metal element nucleus reacts with the metal element nucleus. A central nucleus composed of a two-layer structure of an intermetallic compound layer of the metallic element and tin covering the outer periphery of the metallic element nucleus and the metallic element nucleus is formed, and the central nucleus is covered with a coating layer made of tin And obtaining a solder powder having an average particle size of 5 μm or less.
Priority Applications (1)
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| CN103619529B (en) * | 2011-09-02 | 2015-05-06 | 三菱综合材料株式会社 | Solder powder, and solder paste using solder powder |
| CN104470657A (en) * | 2012-07-06 | 2015-03-25 | 三井金属矿业株式会社 | Composite copper particles, and method for producing same |
| JP6079374B2 (en) * | 2013-03-29 | 2017-02-15 | 三菱マテリアル株式会社 | Solder powder manufacturing method and solder paste using the powder |
| JP6079375B2 (en) * | 2013-03-29 | 2017-02-15 | 三菱マテリアル株式会社 | Solder powder, method for producing the same, and solder paste using the powder |
| US10325693B2 (en) | 2014-08-28 | 2019-06-18 | E I Du Pont De Nemours And Company | Copper-containing conductive pastes and electrodes made therefrom |
| JP6408696B2 (en) | 2014-08-28 | 2018-10-17 | イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニーＥ．Ｉ．Ｄｕ Ｐｏｎｔ Ｄｅ Ｎｅｍｏｕｒｓ Ａｎｄ Ｃｏｍｐａｎｙ | Copper-containing conductive paste and electrode made from copper-containing conductive paste |
| CN106575537A (en) | 2014-08-28 | 2017-04-19 | E.I.内穆尔杜邦公司 | Solar cells with copper electrodes |
| JP6428409B2 (en) * | 2015-03-18 | 2018-11-28 | 三菱マテリアル株式会社 | Solder powder and solder paste using this powder |
| JP6607006B2 (en) * | 2015-12-01 | 2019-11-20 | 三菱マテリアル株式会社 | Solder powder and method for preparing solder paste using the powder |
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| JP2006225691A (en) * | 2005-02-15 | 2006-08-31 | Mitsui Mining & Smelting Co Ltd | Tin-coated copper powder and electrically conductive paste using the tin-coated copper powder |
| JP2006225692A (en) * | 2005-02-15 | 2006-08-31 | Mitsui Mining & Smelting Co Ltd | Tin-coated copper powder and composite electrically conductive paste using the tin-coated copper powder |
| JP2008138266A (en) * | 2006-12-04 | 2008-06-19 | Mitsubishi Materials Corp | Solder powder, and solder paste using the same |
| JP2008149366A (en) * | 2006-12-20 | 2008-07-03 | Mitsubishi Materials Corp | Solder powder, and soldering paste using the same |
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