上世紀90年代初開始,在美國、歐洲和日本等先後立法對鉛在工業上的應用加以限製,並進行無鉛焊料的研究與開發工作,我(wǒ)國對此(cǐ)也十分重視,許多高等院校、科研院所及有條件的企業,都在廣泛開展研究與開發(fā)工作,取得了較(jiào)好(hǎo)的成果,基(jī)本上與國際同步。
含鉛焊料與鉛合金塗覆工藝長期(qī)以來在電子產品製(zhì)造技術中被廣泛應用,尤其是Sn-Pb共晶焊料(liào)以其使用的方便性、穩定的焊接性、價格的合理(lǐ)性作為實用的低溫合(hé)金,從古羅馬時代開始直到當今高密度(dù)的電子組裝,一(yī)直擔任著最適宜的角色。但是由(yóu)於大量電子產(chǎn)品廢棄物及舊家(jiā)用(yòng)電器逐漸造成的鉛汙染,對人類生存的地(dì)球環境也造(zào)成很大的危害,從日(rì)前舉辦(bàn)的第13屆NEPCON展(zhǎn)上展示的電子設備、電子材料(liào)來看,電子(zǐ)組裝業(yè)已開始邁向一個適合綠色環(huán)保(bǎo)要求的新時期。無鉛化電子組(zǔ)裝(zhuāng)工藝已(yǐ)成為新世(shì)紀電子製造業的開發和應用重點。
1990年美國提出了“在所有(yǒu)電子機器的廣泛範圍內禁止使用鉛的法案”,由此世界範圍內開始了電子組裝業替代焊料(無鉛焊料)的研發活動,並對替代焊料的各種應用穩定性、可靠(kào)性等進行了係列(liè)研究。
在目(mù)前的應用情況下,無鉛化組裝還留有一些技術課題,在使用特性、可焊性方麵有以下幾項:潤濕性不(bú)如原來的Sn-Pb焊料(liào);焊接作業性比原來(lái)的差;對波峰焊接會發生的Lift-off還沒有完好的對策;焊點的耐腐蝕(shí)性問題;量產化的品(pǐn)質管理、工藝問題(tí);接合後的長期可靠性(xìng)等。
建立針(zhēn)對無鉛化組裝的簡便式檢測方法是亟(jí)待完善的任務。譬如(rú)無鉛化組裝焊點的外觀檢查,必(bì)須要(yào)建(jiàn)立外觀檢查的有關標準,對於整個行業來說(shuō),應該早日完成行業或國家標(biāo)準。
無鉛化組裝的可靠性,一般來說(shuō)無鉛焊(hàn)料難以發生蠕變,焊料本身同(tóng)樣具(jù)有(yǒu)良好的可靠性,組裝時的不利因素主要來自(zì)組裝元件和基板焊區的組裝應力,這個方(fāng)麵的可行性(xìng)認定,可以(yǐ)由企業自行展開,也(yě)可以通過專業學(xué)會,或企業間共同努力來推進。
在推行無鉛化組裝的(de)過程中,要看到向(xiàng)無鉛化轉移時的時間偏差,如(rú)生產周期短的產(chǎn)品,完成無鉛化可能會簡(jiǎn)單一些,周期長或多品種少批(pī)量的企業向無鉛化轉移(yí)的時間就會長一些。還有一個現象是,對(duì)於無鉛化應用中的判斷、評價,因為目(mù)前的應(yīng)用標準還(hái)沒有,要是不能(néng)及時完善,對產品(pǐn)向無鉛化轉(zhuǎn)移會變得不吻(wěn)合。
無鉛化的推廣(guǎng)應用會帶來應用成本的提升,但是作為(wéi)一(yī)項(xiàng)全球化的應用趨勢,作為整機廠商,對於無鉛化的成本上升問題,應從綜合(hé)的觀點(diǎn)來考慮,最好是在保持產品性價比(bǐ)的基(jī)礎上,消化吸引(yǐn)因無(wú)鉛(qiān)化技術引起的成本上升,這才是適應市場競爭(zhēng)的理性觀點,也是(shì)整機廠(chǎng)、元件廠有待深入探討(tǎo)的問題。
為了人類(lèi)居住(zhù)的地球環境,電子產品推行無(wú)鉛化已是一個不可扭轉的趨(qū)勢,日、歐、美等國的產業研(yán)究所、專業學會曾專門就此事向廣大市(shì)民、中小企業、跨國製造商作了無鉛化調(diào)查,所得到的(de)調查結(jié)果可歸納為下麵幾項。
大企業應該向中小企業提供或公示(shì)無鉛化技術信息。跨國(guó)公司類的著名企業,因經濟(jì)實力雄厚(hòu),可能會先行一步(bù)進入無鉛化(huà)領域,但對於眾(zhòng)多的中小企業,僅依靠自己的技術或(huò)力量(liàng),要一下進入實用無鉛(qiān)化領域(yù),還會存在一些困難,希望已經進入無鉛化技術的大企業能提供(gòng)無鉛應用技術信(xìn)息,為全行業的無鉛化作相應貢獻。
對無(wú)鉛焊料統(tǒng)一命名、製訂相應標準。當前不管是已完成無鉛化的(de)元件(jiàn)廠商,還是焊料(liào)生產廠商,所設定的應用工藝、應用焊料名稱是不統一的,這對於推(tuī)廣中(zhōng)會(huì)出現因供應廠商的不同,所提供的使用(yòng)說明(míng)、技術確認方式(shì)也不同的局麵(miàn),由此隻會給(gěi)無鉛化的推進造成障礙。要徹底解決這個問題,在不同(tóng)廠商之間期待於焊料(liào)組成、組裝(zhuāng)工藝條件、無鉛焊接使用時間的規定等方(fāng)麵的統一是必要的。
國際標準化。關(guān)於無鉛化國際標準的建立(lì),眾多廠商提出“建立向世界各國發布無鉛化技術信息製度”、“在國際標準方案的(de)製訂上要采(cǎi)取(qǔ)主動權”、“向其他國(guó)家發布信(xìn)息或技術轉移的前提是應該設立無鉛化公(gōng)用方案”、“盡快設定世界性的推(tuī)廣(guǎng)應用方(fāng)針,訂出無鉛化SCHEDULE”。這些意見對我們來說應該積極參考(kǎo)。
知識產權與國際協調。電子組裝無(wú)鉛(qiān)化的專(zhuān)利,調查中跨國類公司發表了很多(duō)意見,代表性的有兩點,一是要盡快建立無鉛焊料的專利信息數據庫,二(èr)是應設法使已(yǐ)有(yǒu)的(de)美(měi)國專利經專業網站(zhàn)給予(yǔ)公布(bù),以減少重複申(shēn)請。
現在生產組織性跨國的大公司,基本(běn)是“世(shì)界性工廠”,這類公司生產新技術的應用,生產規模製訂等,必須在不同國家子公司的協(xié)調下才能完成。同樣推廣無鉛化計劃必須要進行國際(jì)間的協調,同(tóng)步展(zhǎn)開才能取得相應效果。
關於無鉛化的技術標準,從目前還在使用的(de)鉛錫焊料來說,在共晶焊料以外已有多種焊料(liào)標準,對應的作用也很廣。鉛錫焊(hàn)料的特征反映(yìng)在不同產(chǎn)品上的使用方便性,所以不一定要強製設立標準。對於無鉛化推廣來(lái)說,應用標準不一定是單一品種組成的統一,主要是指所限定焊料合金係的應用範(fàn)疇與分類。例如日本NEDO的執(zhí)行方案中已對無鉛焊料(liào) 的標準分類有了提案。
與無鉛化標準發(fā)生牽連(lián)的另一方麵(miàn)是元器件連接電極鍍層(金屬)是(shì)否同無鉛焊料取得統一。對這個問題首先要搞清楚在組裝(zhuāng)基板焊區、元件電極與使用的無(wú)鉛焊料(liào)間有(yǒu)沒有等同性的(de)必要。同類焊料和不同(tóng)類元素混放時給產品會帶來什麽樣的影響,同時也有待於權威性標準化組織在綜合各方麵的意見後提出(chū)相應的建議。
無鉛化國際標(biāo)準的建立對推動這項事業是有利的。目前公(gōng)開的技術信息,專利文(wén)獻還(hái)不是很(hěn)多,但隨著今後國(guó)際法規時間表推(tuī)出,一定會(huì)形成一個適用性很強的標準框架。
無鉛焊接應用案(àn)例
SONY(索(suǒ)尼)公司從1996年開始a研究無鉛化組(zǔ)裝工藝,並在無鉛化的可(kě)靠性、量產性、成本性方麵對Sn-Ag係、Sn-Zn係焊料進行了驗證。在1999年的第三季度與500多(duō)家元器件製造銷售商進行無(wú)鉛化協商,簽訂了無鉛實用化協議。
在(zài)無鉛產品商品化推廣中,2000年3月向市場推出DCR-TRV20數碼攝錄一體機。
NEC 從NEC公司的對外公告上獲知(zhī),其2002年(nián)Sn-Pb焊料的使用量同1997 年相比削(xuē)減50%。20 00年(nián)以來,NEC已(yǐ)在多種產品上執行了無鉛化,於1999 年率先在筆記本電腦上進入量產化生產。
FUJITSU研(yán)究(jiū)所
FUJITSU研究所(suǒ)於(yú)1999年10月發表了無鉛化在“全球通信程序服務器GS8900”的應用。GS8900全球通信程序服務器中的(de)MCM無(wú)鉛化組裝(分級焊接(jiē)),這種分級焊接無鉛化方式今後還將在更多的(de)高端(duān)產品中(zhōng)得到應用。
Panasonic
鬆下公司從1998年開始在便攜式數碼音(yīn)頻(pín)產品“MD”上進行了無鉛化量產(chǎn)生產。近年(nián)來已形成P-MD 產品的無鉛化係列。
Since the beginning of the 1990s, in the United States, Europe and Japan have legislation to limit the application of lead in the industry to be limited, and lead-free solder research and development work, our country also attaches great importance to many institutions of higher learning, scientific research Institutions and qualified enterprises, are in a wide range of research and development work, and achieved good results, basically with the international synchronization. The same time as
Lead-containing solder and lead alloy coating process has long been widely used in electronic product manufacturing technology, especially Sn-Pb eutectic solder with its convenience, stable welding, the price of rationality as a practical low-temperature alloys , From the ancient Roman era until today's high-density electronic assembly, has served as the most appropriate role. However, due to a large number of electronic products and old household appliances and lead gradually lead pollution, the human environment of the human environment also caused great harm, from the recently held at the 13th NEPCON show on the display of electronic equipment, electronic materials, Electronic assembly has begun to move towards a new era of green environmental requirements. Lead-free electronic assembly technology has become the new century, the development and application of electronic manufacturing focus. The same time as
In 1990, the United States proposed the Act on the Prohibition of the Use of Lead in the Extensive Range of All Electronic Machines, which began the development of alternative solder (lead-free solder) in the electronic assembly industry and the various applications of alternative solders Stability, reliability and so on a series of studies. The same time as
In the current application, the lead-free assembly also left some technical issues, the use of characteristics, solderability aspects of the following: wetting less than the original Sn-Pb solder; welding work than the original poor; The Lift-off of the wave soldering will not have a good countermeasure; the corrosion resistance of the solder joint; the quality management of the mass production, the process problem; the long-term reliability after the joining. The same time as
The establishment of a simple detection method for lead-free assembly is an urgent task. For example, the appearance of lead-free assembly of solder joints inspection, must establish the relevant standards of inspection, for the entire industry, should be completed early industry or national standards. The same time as
Lead-free assembly of the reliability, in general, lead-free solder is difficult to creep, the solder itself has the same good reliability, the assembly of the unfavorable factors mainly from the assembly components and substrate welding area of the assembly stress, this aspect of the feasibility Identified, can be launched by the enterprise itself, you can also learn through professional, or to work together to promote the enterprise. The same time as
In the process of lead-free assembly, to see the time shift to lead-free transfer, such as the short production cycle of the product, the completion of lead-free may be simple, long or many varieties of small batch of enterprises to no Lead transfer time will be longer. There is also a phenomenon, for the application of lead-free evalsuation, evalsuation, because the current application standards have not, if not timely improvement of the product to lead-free transfer will become inconsistent. The same time as
Lead-free application will bring the application of the cost of upgrading, but as a global application trends, as a whole machine manufacturers, the cost of lead-free rise, should be considered from a comprehensive point of view, it is best to maintain Product cost-effective on the basis of digestion and attracting lead-free technology caused by rising costs, this is to adapt to market competition rational point of view, but also machine factory, component plant to be further explored. The same time as
In order to human living in the global environment, the implementation of lead-free electronic products is an irreversible trend, Japan, Europe, the United States and other countries of the Institute of Industry, professional society has specialized on the matter to the general public, small and medium enterprises, multinational manufacturers The results of the survey can be summarized as follows. The same time as
Large enterprises should provide or publicize lead-free technical information to small and medium-sized enterprises. Multinational companies like the famous enterprises, due to economic strength, may be the first step into the field of lead-free, but for many small and medium enterprises, relying solely on their own technology or strength, to enter the field of practical lead-free, there will be some Difficult, hope that has entered the lead-free technology, large enterprises can provide lead-free application of technical information for the industry-wide lead-free contribution to the corresponding. The same time as
Lead free solder named after the formation of the corresponding standards. Whether the current has been completed lead-free component manufacturers, or solder manufacturers, set the application process, the application of solder name is not uniform, which will appear in the promotion due to the different manufacturers, provided instructions, Technical confirmation is also a different situation, which will only lead to lead to promote the obstacles. It is necessary to completely solve this problem, and it is necessary to unify the consistency between the different manufacturers and the requirements of the composition of the solder, the assembling process conditions and the lead-free soldering time. The same time as
International Standardization. On the establishment of international standards for lead-free, many manufacturers put forward the "establishment of the world to publish lead-free technology information system", "in the development of international standard programs to take the initiative", "to other countries to publish information or technology transfer The premise is that should be set up lead-free public program "," as soon as possible to set the world to promote the application of guidelines, made of lead-free SCHEDULE ". These comments should be a positive reference for us. The same time as
Intellectual Property and International Coordination. Electronic assembly of lead-free patent, the survey of multinational companies published a lot of opinions, there are two representative, one is to establish a patented information database as soon as possible lead-free solder, the second is to try to make the existing US patents by professional The website is given a notice to reduce duplicate applications. The same time as
Now the production of organized transnational large companies, the basic "world factory", the production of new technologies such companies, the scale of production, etc., must be coordinated in different countries to complete the subsidiary. The same promotion of lead-free plan must be carried out international coordination, synchronized to achieve the appropriate effect. The same time as
On the lead-free technical standards, from the currently used lead-tin solder, eutectic solder in addition to a variety of solder standards, the corresponding role is also very wide. The characteristics of the lead solder are reflected in the ease of use on different products, so it is not necessary to enforce the standard. For lead-free promotion, the application of standards is not necessarily a single species of unity, mainly refers to the limited scope of the application of solder alloy and classification. For example, Japan NEDO implementation of the program has been on the standard classification of lead-free solder with a proposal. The same time as
Another aspect related to lead-free standards is whether the electrode-attached electrode coating (metal) is united with lead-free solder. The first question on this issue is to find out whether there is any need for uniformity between the component electrodes and the lead-free solders used in assembling the substrate pads. Similar products and different types of elements mixed when the product will bring what kind of impact, but also to be authoritative standardization organizations in the comprehensive views of various aspects of the corresponding recommendations. The same time as
The establishment of international standards for lead-free to promote the cause is beneficial. The current disclosure of technical information, patent literature is not a lot, but with the future international regulatory timetable introduced, will form a very applicable standard framework. The same time as
Lead - free soldering applications
SONY (Sony) from 1996 to study a lead-free assembly process, and in the lead-free reliability, mass production, cost of Sn-Ag, Sn-Zn solder was verified. In the third quarter of 1999 with more than 500 components manufacturing and sales of lead-free consultation, signed a lead-free utility agreement. The same time as
In the lead-free product commercialization promotion, in March 2000 to market the market DCR-TRV20 digital camcorder. The same time as
NEC from NEC's external announcement that its 2002 Sn-Pb solder usage compared with 1997 reduced by 50%. Since 20 years, NEC has been in a variety of products on the implementation of the lead-free, in 1999 took the lead in the notebook computer into mass production. The same time as
FUJITSU Institute
The FUJITSU Institute published the lead-free application in the "Global Communications Program Server GS8900" in October 1999. GS8900 global communication program server MCM lead-free assembly (graded welding), this grading welding lead-free way in the future will be more high-end products in the application. The same time as
Panasonic
Matsushita Corporation since 1998 in the portable digital audio products "MD" on the lead-free production. In recent years has formed P-MD products lead-free series.