200403965 (1) 玖、發明說明 【發明所屬之技術領域】 本發明係有關於一種使用熔融Sn-Ag-Cu系無鉛銲錫 以實施配線基板和電子零件之錫銲的方法，且特別有關於 一種管理流動銲錫浴而使可靠度很高的錫銲方法。 【先前技術】 將電子零件搭載到配線基板以實施錫銲安裝之手段， 有使配線基板下表面接觸到收容熔融銲錫的銲錫浴，使電 子零件之導線連接到配線基板之電路端子部，亦即所謂之 流動安裝正被廣泛使用中（參照日本特開2001-308508號 公報）。 .可是，過去在上述安裝中，用於實施配線圖樣和電子 零件接合之銲錫材料，有錫-鉛共晶銲錫，其因爲對於電 極材料之濕濡性、接合可靠性及錫銲溫度等很優良，所以 逐漸被廣泛採用。可是，正被電子機器廣泛使用之上述含 鉛銲錫材料一旦被廢棄的話，對人體有害的鉛會溶出到環 境中’很有可能會引起重金屬污染，所以，近年來不含給 之所謂無給銲錫材料正快速地被採用中。 現在’流動女裝用無給銲錫材料，有Sn-Ag-Cu系、 Sn-Cu系及Sn-Zn系等材料被廣泛知悉，而這些銲錫材料 之中’ Sn-Ag-Cu系及Sn-Cii系之銲錫材料很穩定，所以 被廣泛採用。 42合 又’電子零件之端子部材料，有銅或鐵，或者 (2) (2)200403965 金等Fe-Ni系合金被採用，這些端子部材料表面爲了改善 錫銲時之濕濡性，而有實施Sn-Pb等組成之電鍍。 可是，使用現在一般採用中之無鉛銲錫材料以實施流 動安裝的話，在銲錫固化時，針狀之金屬間化合物或析出 物會在錫銲過之端子部及接近前述端子部之其他不期望部 分之間，以架橋狀態固著，產生所謂架橋，而會引起短 路。 改善上述架橋現象之方法，有在實施流動安裝之錫銲 裝置中，在錫銲部脫離銲錫浴的瞬間，藉由加熱器等加熱 錫銲部以阻止纖維狀物之形成，而防止架橋之產生（參照 日本特開2 00 1 -3 0 8 5 0 8號公報）。可是，利用上述方法的 話’必須改造錫銲裝置本身，又，此複雜的方法有必要在 配線基板脫離銲錫浴之瞬間噴射熱風，而需要非常高精度 之控制。 【發明內容】 〔發明所欲解決的課題〕 本發明之目的，係爲改善採用無鉛銲錫的流動安裝法 中之上述問題點，而提供一種藉由簡易的方法有效地防止 架橋現象，而且接合可靠度很高的錫銲方法。 〔用於解決課題的手段〕 本發明係用於解決上述習知技術之課題而開發出之錫 銲方法，其中，其爲使用熔融Sn-Ag-Cu系無鉛銲錫以實 -6 - (3) (3)200403965 施配線基板和電子零件之錫銲的方法，其特徵在於：調整 銲錫浴之組成，以使熔融銲錫浴中之銅元素係〇. 5〜1 · 1 5 重量％範圍內，並且鉛元素相當於不純物之濃度。 在上述本發明之錫銲方法中，鉛元素之組成係在3 00 〜3500 ppm範圍內。 又，在上述本發明中，前述銲錫浴組成調整之實施， 係藉由在前述銲錫浴組成中，添加不含銅元素及鉛元素之 其他至少一項成分，或者，添加自初期銲錫浴組成中削減 銅元素及鉛元素之物質。 更有基者，在上述本發明中，前述銲錫浴組成之管 理，能夠在銲錫浴經過既定使用時間後，自銲錫浴中取樣 銲錫，針對取樣出的銲錫實施元素分析，當銅元素及鉛元 素之至少一者脫離既定範圍時，藉由將構成前述銲錫浴之 至少一項元素成分添加到前述銲錫浴材料中，以使銲錫浴 組成回復到既定範圍；或者，在浸漬入銲錫浴的配線基板 數量達到既定數目後，自銲錫浴中取樣銲錫，實施元素分 析，當銅元素及鉛元素之至少一者脫離既定範圍時，藉由 將構成前述銲錫浴之至少一項元素成分添加到前述銲錫浴 材料中，以使銲錫浴組成回復到既定範圍。 上述本發明，係依據檢討採用流動銲錫浴之安裝而獲 得之下列見識所產生者。亦即，Sn-Ag-Cu系銲錫材料， 係在錫銲工序中，對於配線基板接地部或配線圖案之銅的 腐蝕量很少，而且能實施銲錫浴組成穩定之錫銲，但是， 即使在這種銲錫浴中，銅元素也會從使用於配線基板上之 (4) (4)200403965 導電材料熔出，當蓄積於銲錫浴中之銅元素達到既定濃度 以上時，銲錫浴之黏度會上升，而成爲產生架橋之原因。 在此’針對此銲錫浴定期實施組成分析，如果銅元素含量 被檢出達到一定値以上時，則添加不足或缺少的原料以調 整組成，藉此，能有效避免架橋現象。 又，如果濃度相當於存在上述銲錫浴中不純物的鉛元 素存在的話，因爲會降低銲錫浴之黏度，所以，即使在含 有更高濃度銅元素的銲錫浴中，也能抑制架橋產生，延長 調整銲錫浴組成之間隔時間，而且能減少錫銲工序之工 時，有效率地實施銲錫浴管理。本發明即得知上述關係而 完成者。 在本發明中，將銲錫浴組成之管理範圍設定於銅元素 含量爲0 · 5〜1 · 1 5重量％ ;鉛元素含量相當於不純物含量 之範圍，更具體說的話，鉛元素含量在3 00〜3 5 00 ppm之 間，其理由在於：當銅元素在銲錫浴中之含量低於〇 . 5 % 的話，會有濕濡性降低而減低錫銲可靠性之問題，或者， 會有對於使用在配線基板之銅材料的腐蝕量大的問題，所 以，不是很好。另外，如果銅元素在銲錫浴中之含量高於 1 · 1 5 °/。的話，銲錫浴黏度會上升，容易形成針狀金屬間化 合物或析出物，而成爲銲錫架橋之原因，錫銲不良修整率 會增加。 又，如果鉛元素在銲錫浴中之含量低於3 00 ppm的 話，銅元素之適當組成範圍係0.5〜1.0重量％左右，其 非常狹窄，會增加銲錫浴調整之工序，使作業效率降低。 -8 - (5) (5)200403965 另外，如果鉛元素在銲錫浴中之含量高於3 500 ppm的 話，除了在銲錫材料凝固中，銲錫會部分剝離，亦即經常 會產生所謂浮豎（lift-off )現象之外，也必須採取防止因 爲鉛溶出而造成環境問題之對策，非常不經濟。 在上述本發明中，前述銲錫浴組成之調整，最好藉由 在前述銲錫浴組成中，添加不含銅元素及鉛元素之其他成 分的至少一項來實施。另，在上述本發明中，前述銲錫浴 組成之調整，最好藉由在前述銲錫浴組成中，添加使銅元 鲁 素及鉛元素自初期銲錫浴組成中減量之成分組成的材料來 實施。 在上述本發明中，前述銲錫浴之組成管理，最好在銲 錫浴經過既定使用時間後，自銲錫浴中取樣銲錫，針對取 樣出的銲錫實施元素分析，當銅元素及鉛元素之配合比脫 離既定範圍時，藉由將構成前述銲錫浴之至少一項元素成 分添加到前述銲錫浴材料中，以使銲錫浴組成回復到既定 範圍。 φ 在上述本發明中，前述銲錫浴之組成管理，最好在浸 漬入銲錫浴的配線基板數量達到既定數目後，自銲錫浴中 取樣銲錫，實施元素分析，當銅元素及鉛元素之至少一者 脫離既定範圍時，藉由將構成前述銲錫浴之至少一項元素 成分添加到前述銲錫浴材料中，以使銲錫浴組成回復到既 定範圍。 上述本發明，係本案申請人依據爲了解決上述課題而 檢討後所獲得之下述見識而得者。亦即，在無鉛銲錫中， -9- (6) (6)200403965 隨著重複錫銲工序，銲錫浴組成中構成電路圖案之銅元素 或構成電子零件導線之銅元素會熔解到銲錫浴中而蓄積。 結果，可以瞭解到：銲錫浴黏度會上升，在錫銲工序中生 成針狀金屬間化合物或析出物，其爲造成架橋之原因。 復，可以瞭解到：同樣地在無鉛銲錫中，如果導線電鍍材 料等所含有的鉛元素會熔解混入到銲錫浴組成中的話，接 合部之凝固溫度範圍會擴大。特別，當鉛元素細微偏析的 話，在錫銲接合之表層部中，銲錫雖然會凝固，但是在銲 錫內部中，會殘留未凝固之低黏度熔融銲錫區域，此區域 在逐漸凝固的過程中，因爲基板等的凝固收縮而應力會增 加，而會產生錫銲接合之剝離或變形。因此，想到藉由管 理及控制銲錫浴組成，能防止架橋或浮豎（lift-off)現象 之產生，乃至完成本發明。 【實施方式】 〔發明之最佳實施型態〕 # 以下，詳細說明本發明之實施型態。 本發明中所採用之無鉛銲錫材料，可以使用眾所周知 的Sn-Ag-Cu系銲錫。銲錫材料雖然依各別材料而異，可 是，大體上，在氮氣環境氣體中，於250^2 °C之溫度範圍 下維持熔融，可使用於流動安裝之錫銲工序。 隨著配線基板錫銲工序數量之增加，銅、鉛及其他金 屬會熔解混入銲錫浴中，銲錫浴組成隨著銲錫浴使用時間 之增加，或者浸漬到銲錫浴中配線基板數目之增加，組成 -10 - (7) (7)200403965 會逐漸改變。亦即，銅、鉛及鐵等，配線基板之配線圖案 材料、搭載於配線基板之電子零件導線材料或者電鍍到前 述導線表面之材料等所函知金屬元素會熔解混入銲錫浴 中’這些金屬元素之比率會上升，不使用於配線基板中之 錫、銀等元素的比率會相對降低。 在此，經常或採取適當間隔時間自銲錫浴中取樣銲錫 材料’使用ICP分析法等元素分析法，定量分析銲錫浴之 構成元素，以調查銲錫浴之組成。而且，爲了在此組成脫 離既定範圍之階段，補充銲錫浴組成中缺乏的元素，而添 加比率正在增加中之銅、鉛元素以外的無鉛銲錫材料構成 元素到銲錫浴中。或者，將銅、鉛元素之外的成分很豐富 的銲錫材料添加到銲錫浴中。 上述補充元素之添加，可以各別添加正欠缺之各個金 屬元素，也可以添加預先將銅及鉛以外之構成金屬元素熔 融合金化而製成之顆粒。如果使用添加上述合金化顆粒之 方法的話，銲錫浴組成管理能快速實施，非常實用。又， 將這些金屬元素在添加到銲錫浴之前事先加以熔融，而以 熔融金屬添加的話，能夠更加快速地調整銲錫浴組成。 另，補充金屬也可以添加自初期階段所用之銲錫組成中， 降低銅元素及鉛元素配合比率之材料。藉此，能使組成調 整頻率變得很高之銲錫，讓組成調整結果及組成變均一之 時間縮短。 〔實施例〕 -11 - (8) 200403965 將含有350 ppm鉛元素而且具有Sn-Ag-Cu組成 錫6 0 0公斤加以熔融’然後維持2 5 〇艺而成爲銲錫浴 述銲錫浴中’使銅含量爲0.52% 。使零件數量1 1〇〇 雙面配線基板內面浸漬到上述銲錫浴中3 · 5秒，以實 驛。如上述程序，每處理約1 0000片配線基板後，在 浴材料維持熔融之狀態下，將銲錫材料取樣5〇〇公克 由ICP元素分析法實施元素分析，與初期之銲錫浴材 成做比較。當重複此循環5次時，因爲鉛元素含 3 1 00 ppm，而銅元素含量達到1 · 1 5% ，所以，將日常 到銲錫浴中之銲錫，由Sn-Ag-Cu系改變成Sn-Ag系。 在以上述方法實施組成管理的銲錫浴中，雖然實 1〇〇, 〇〇〇張配線基板之安裝，但是，架橋發生率爲 ppm以下，浮豎（iift-0ff )現象發生率爲2%以下 此’架橋發生率，係將架橋產生數量除以全部錫銲點 比率；浮豎（lift_off )現象發生率，係將浮豎（ off )現象產生數量除以全部錫銲點數之比率。 另外，完全不以上述方法實施銲錫浴管理之銲錫 實施過50,000張配線基板之錫銲後，銲錫架橋發生 第40,000張以後會增加，達到1〇〇〇〜1200 ppm又， (lift-off)現象發生率約達到50% 。 〔發明效果〕 使用上述說明過之本發明的話，在使用不引起環 染之無鉛銲錫之同時，即使銲錫浴長時間使用，也不 之銲 °刖 件之 施錫 婷錫 ，藉 料組 量爲 添加 施過 600 。在 數之 lift- 浴， 率在 浮豎 境污 會產 -12- (9)200403965 生銲錫架橋或浮豎（lift-off)現象，而發揮能實施高可靠 性錫銲之特徵效果。200403965 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for performing soldering of a wiring substrate and an electronic component using molten Sn-Ag-Cu lead-free solder, and particularly to a management A highly reliable soldering method with a flowing solder bath. [Prior technology] The method of mounting electronic components on a wiring substrate for soldering installation involves contacting the lower surface of the wiring substrate with a solder bath containing molten solder, and connecting the wires of the electronic components to the circuit terminal portion of the wiring substrate, that is, The so-called mobile installation is being widely used (see Japanese Patent Application Laid-Open No. 2001-308508). However, in the past, in the above-mentioned installation, solder materials used for the implementation of wiring patterns and electronic parts bonding include tin-lead eutectic solder, which is excellent in wettability of electrode materials, bonding reliability, and soldering temperature. , So it is gradually widely adopted. However, once the above-mentioned lead-containing solder materials that are widely used in electronic equipment are discarded, lead harmful to human body will be dissolved into the environment. It is likely to cause heavy metal pollution. It is being adopted quickly. At present, 'unsold solder materials for mobile women's clothing are widely known as Sn-Ag-Cu, Sn-Cu, and Sn-Zn. Among these solder materials,' Sn-Ag-Cu and Sn-Cii ' The solder material is very stable, so it is widely used. The materials of the terminal parts of 42heyou's electronic parts are copper or iron, or (2) (2) 200403965 gold and other Fe-Ni based alloys are used. The surface of these terminal part materials is to improve the wettability during soldering. There is electroplating of Sn-Pb and other components. However, when using lead-free solder materials that are currently commonly used for flow mounting, needle-shaped intermetallic compounds or precipitates will form in the soldered terminals and other undesired parts near the terminals when the solder is cured. At the same time, it is fixed in a bridged state, so-called bridging occurs, which may cause a short circuit. To improve the bridging phenomenon mentioned above, in a soldering device for mobile installation, when the soldering part is released from the solder bath, the soldering part is heated by a heater or the like to prevent the formation of fibrous objects and prevent the generation of bridging. (Refer to Japanese Patent Laid-Open No. 2001-3 0 8 5 0 8). However, if the above method is used, the soldering apparatus itself must be modified, and this complicated method requires the hot air to be sprayed as soon as the wiring board is released from the solder bath, and very precise control is required. [Summary of the Invention] [Problems to be Solved by the Invention] The object of the present invention is to improve the above-mentioned problems in the flow mounting method using lead-free solder, and to provide a simple method to effectively prevent the bridging phenomenon and reliable bonding. High degree of soldering method. [Means for Solving the Problems] The present invention is a soldering method developed to solve the problems of the above-mentioned conventional technology. Among them, a molten Sn-Ag-Cu-based lead-free solder is used.-6-(3) (3) 200403965 A method for applying soldering to wiring substrates and electronic parts, which is characterized in that the composition of the solder bath is adjusted so that the copper element in the molten solder bath is in the range of 0.5 to 1.5% by weight, and The lead element corresponds to the concentration of impurities. In the above-mentioned soldering method of the present invention, the composition of the lead element is in the range of 3 00 to 3500 ppm. In the present invention, the solder bath composition adjustment is performed by adding at least one component that does not contain copper and lead elements to the solder bath composition, or by adding it to the initial solder bath composition. Substances that reduce copper and lead. More fundamentally, in the above invention, the management of the aforementioned solder bath composition can be used to sample solder from the solder bath after a predetermined use time of the solder bath, and perform elemental analysis on the sampled solder. When the copper and lead elements are When at least one of them deviates from the predetermined range, at least one element component constituting the solder bath is added to the solder bath material to restore the solder bath composition to the predetermined range; or the wiring substrate immersed in the solder bath After the quantity reaches a predetermined number, solder is sampled from the solder bath and elemental analysis is performed. When at least one of the copper element and the lead element leaves the predetermined range, at least one element component constituting the solder bath is added to the solder bath. Material to restore the solder bath composition to a predetermined range. The present invention described above is the result of the following insights obtained by reviewing the installation using a flowing solder bath. That is, the Sn-Ag-Cu based solder material is used in the soldering process, has a small amount of copper corrosion on the grounding portion of the wiring board or the wiring pattern, and can perform stable soldering with a solder bath composition. In this solder bath, the copper element will also be melted out of (4) (4) 200403965 conductive material used on the wiring substrate. When the copper element stored in the solder bath reaches a predetermined concentration or higher, the viscosity of the solder bath will increase. , And become the cause of bridges. Here's a regular composition analysis for this solder bath. If the copper content is detected to be above a certain level, add insufficient or missing raw materials to adjust the composition, thereby effectively avoiding bridging. In addition, if the concentration of lead element corresponding to the presence of impurities in the solder bath is present, the viscosity of the solder bath will be reduced. Therefore, even in a solder bath containing a higher concentration of copper element, bridging can be suppressed and the solder can be adjusted for a longer period of time. The interval time of the bath composition can also reduce the man-hours of the soldering process and efficiently implement the solder bath management. The present invention has been completed by learning the above-mentioned relationship. In the present invention, the management range of the composition of the solder bath is set to a copper element content of 0. 5 to 1. 15 weight%; the lead element content is equivalent to the range of the impurity content, and more specifically, the lead element content is 300 The reason is between ~ 3,500 ppm: when the content of copper in the solder bath is less than 0.5%, there is a problem that the wettability is reduced and the reliability of soldering is reduced, or there is a problem for use The problem of large amount of corrosion of the copper material in the wiring board is not good. In addition, if the copper content in the solder bath is higher than 1 · 15 ° /. In this case, the viscosity of the solder bath will increase, and acicular intermetallic compounds or precipitates will be easily formed, which will cause the solder bridging, and the defective solder repair rate will increase. If the content of lead element in the solder bath is less than 300 ppm, the proper composition range of copper element is about 0.5 to 1.0% by weight, which is very narrow, and the process of adjusting the solder bath is increased, which reduces the work efficiency. -8-(5) (5) 200403965 In addition, if the content of lead element in the solder bath is higher than 3 500 ppm, the solder will be partially peeled apart from the solidification of the solder material, that is, the so-called lift is often generated. -off) phenomenon, it is necessary to take measures to prevent environmental problems caused by lead elution, which is very uneconomical. In the present invention described above, the adjustment of the solder bath composition is preferably performed by adding at least one of other components that do not contain a copper element and a lead element to the solder bath composition. Further, in the present invention described above, the adjustment of the solder bath composition is preferably performed by adding a material composition that reduces the amount of copper elements and lead elements from the initial solder bath composition to the solder bath composition. In the above-mentioned present invention, the composition management of the aforementioned solder bath is preferably performed after the solder bath has passed a predetermined use time, sampling the solder from the solder bath, and performing elemental analysis on the sampled solder. When the mixing ratio of the copper element and the lead element is separated In the predetermined range, at least one element component constituting the solder bath is added to the solder bath material to restore the solder bath composition to the predetermined range. φ In the above-mentioned present invention, the composition management of the aforementioned solder bath is preferably performed after the number of wiring substrates immersed in the solder bath reaches a predetermined number, solder is sampled from the solder bath, and elemental analysis is performed. When the person is out of the predetermined range, at least one element component constituting the solder bath is added to the solder bath material to restore the solder bath composition to the predetermined range. The above-mentioned present invention is obtained by the applicant of the present case based on the following knowledge obtained after review in order to solve the above-mentioned problems. That is, in the lead-free solder, -9- (6) (6) 200403965 With the repeated soldering process, the copper element constituting the circuit pattern in the solder bath composition or the copper element constituting the lead of the electronic part will melt into the solder bath and Accumulation. As a result, it can be understood that the viscosity of the solder bath increases, and acicular intermetallic compounds or precipitates are generated during the soldering process, which is the cause of bridging. It can be understood that, similarly, in lead-free solder, if the lead element contained in the wire plating material is melted and mixed into the solder bath composition, the solidification temperature range of the joint portion will be expanded. In particular, when the lead element is slightly segregated, although the solder solidifies in the surface layer portion of the solder joint, in the interior of the solder, an unsolidified low-viscosity molten solder region remains. This region is gradually solidifying because The stress of the substrate and the like solidifies and shrinks, and peeling or deformation of the solder joint occurs. Therefore, it is thought that by managing and controlling the composition of the solder bath, it is possible to prevent the occurrence of bridging or lift-off, and even complete the present invention. [Embodiment] [Best Embodiment of Invention] # Hereinafter, the embodiment of the present invention will be described in detail. As the lead-free solder material used in the present invention, a well-known Sn-Ag-Cu-based solder can be used. Although the solder material varies depending on each material, in general, it can be maintained in a temperature range of 250 ^ 2 ° C in a nitrogen ambient gas, which can be used for the soldering process of mobile installation. With the increase of the number of soldering processes on the wiring substrate, copper, lead and other metals will melt and mix into the solder bath. The composition of the solder bath increases with the use of the solder bath, or the number of wiring substrates immersed in the solder bath increases. 10-(7) (7) 200403965 will change gradually. That is, copper, lead, iron, etc., the wiring pattern material of the wiring board, the wire material of electronic parts mounted on the wiring board, or the material plated on the aforementioned wire surface, and other known metal elements will melt and mix into the solder bath. These metal elements The ratio will increase, and the ratio of elements such as tin and silver that are not used in the wiring substrate will relatively decrease. Here, samples of solder materials from the solder bath are often taken at appropriate intervals, and the elemental analysis methods such as ICP analysis are used to quantitatively analyze the constituent elements of the solder bath to investigate the composition of the solder bath. In addition, in order to supplement the missing elements in the composition of the solder bath at the stage where the composition deviates from the predetermined range, the addition ratio is increasing to the elements of lead-free solder materials other than copper and lead in the solder bath. Alternatively, a solder material rich in components other than copper and lead may be added to the solder bath. The addition of the above-mentioned supplementary elements may be the addition of individual metal elements that are lacking, or particles made by melting and metallizing the constituent metal elements other than copper and lead in advance. If the method of adding the above alloyed particles is used, the composition management of the solder bath can be implemented quickly, which is very practical. In addition, these metal elements are melted before being added to the solder bath, and when the molten metal is added, the solder bath composition can be adjusted more quickly. In addition, supplementary metals may be added to the composition of the solder used in the initial stage to reduce the proportion of copper and lead elements. As a result, the solder whose composition adjustment frequency becomes very high can shorten the composition adjustment result and the time for uniform composition. [Example] -11-(8) 200403965 melted 600 kg of tin containing 350 ppm of lead and having a Sn-Ag-Cu composition, and then maintained it at 250 ° C to form a solder bath described in the solder bath to make copper The content is 0.52%. The number of parts 1 100 was immersed in the above-mentioned solder bath for 3 to 5 seconds to complete the inside of the double-sided wiring board. As described above, after processing about 10,000 wiring substrates, the solder material is sampled for 500 grams while the bath material remains molten, and elemental analysis is performed by ICP elemental analysis, which is compared with the initial solder bath material. When this cycle is repeated 5 times, since the lead element contains 3 1 00 ppm and the copper element content reaches 1 · 15%, the solder used in the daily solder bath is changed from Sn-Ag-Cu system to Sn- Ag system. In the solder bath that is managed by the composition method described above, although 10,000 wiring boards are installed, the bridging rate is less than ppm, and the floating vertical (iift-0ff) phenomenon is less than 2%. The occurrence rate of bridging is the ratio of the number of bridges generated divided by the total solder joints; the occurrence rate of the lift-off phenomenon is the ratio of the number of floating vertical (off) divisions divided by the total number of solder joints. In addition, after soldering 50,000 wiring substrates without using the solder bath management method described above, the solder bridging will increase after the 40,000th, reaching 1000 ~ 1200 ppm. The incidence rate is about 50%. [Effects of the Invention] When the present invention described above is used, the lead-free solder that does not cause ring staining is used, and even if the solder bath is used for a long time, the soldering tin tin tin is not used. Over 600. In the number of lift-baths, the pollution in the floating vertical environment will produce -12- (9) 200403965 raw solder bridging or lift-off phenomenon, and exert the characteristic effect of high reliability soldering.
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