印制電路板高速電鍍通孔的研究
發(fā)布時(shí)間：2018-11-01 13:42
【摘要】：金屬銅具有良好的導(dǎo)電性和導(dǎo)熱性,其鍍層可用于實(shí)現(xiàn)印制電路板的孔金屬化。由于電子產(chǎn)業(yè)的快速發(fā)展,印制電路板的尺寸逐漸減小,性能要求逐漸升高。這就要求板上的線路更精細(xì),通孔的厚徑比更高,鍍層的穩(wěn)定性更好。厚徑比的升高使得鍍液的分散能力降低,加大了孔金屬化的難度。并且,隨著印制電路板需求量的逐漸增大,需要提高電流密度,縮短電鍍時(shí)間,采用高速電鍍工藝,從而增大了電路板不同區(qū)域的濃差極化,對(duì)印制電路板電鍍銅提出了更大的挑戰(zhàn)。目前,通過新開發(fā)電鍍添加劑,提高電鍍液的均鍍能力,可以較好地滿足日益提高的電鍍銅要求。本文從添加劑的作用機(jī)理入手,創(chuàng)立了新的添加劑性能評(píng)估方法,并通過實(shí)驗(yàn)驗(yàn)證了方法的準(zhǔn)確性。采用循環(huán)伏安剝離法可以對(duì)抑制劑進(jìn)行定性分析和定量分析,根據(jù)不同抑制劑的循環(huán)伏安曲線相似度來判斷它們的性能差異;將鍍液的循環(huán)伏安曲線與標(biāo)準(zhǔn)曲線對(duì)比,可以計(jì)算出鍍液中的抑制劑濃度。采用計(jì)時(shí)電位法可以對(duì)電鍍銅整平劑進(jìn)行性能評(píng)估,銅沉積電位的負(fù)移幅度越大,表明整平劑對(duì)沉積電位的影響越大,整平性能越好。加入整平劑后,若電位負(fù)移幅度超過30毫伏,可對(duì)其進(jìn)一步測(cè)試,采用這種方法對(duì)劣質(zhì)整平劑進(jìn)行初次淘汰。在電鍍過程中,氧化還原電對(duì)會(huì)在鍍液中發(fā)生氧化還原反應(yīng),與銅離子的沉積反應(yīng)競(jìng)爭(zhēng)消耗電能,降低電鍍銅的電流效率,利用板面和孔內(nèi)電流效率降低的程度不同,達(dá)到改善鍍液均鍍能力的目的。本文在鍍液中分別加入硫酸鐵和對(duì)苯醌這兩種含有氧化還原電對(duì)的化合物,研究了它們對(duì)高速電鍍銅的鍍液性能的影響。結(jié)果表明,微量的鐵離子不會(huì)改變電鍍液的均鍍能力;對(duì)苯醌會(huì)在鍍液下實(shí)現(xiàn)氧化態(tài)和還原態(tài)的不斷轉(zhuǎn)換,影響電流效率,提高鍍液的均鍍能力,因此能夠應(yīng)用于電鍍銅工藝中。在不同電鍍條件下,有機(jī)添加劑在印制電路板上的吸附狀態(tài)也有所不同。本文對(duì)鍍液的重要成分配比進(jìn)行了優(yōu)化實(shí)驗(yàn)設(shè)計(jì),得到了一組符合高速電鍍銅的施鍍參數(shù),并發(fā)現(xiàn)光亮劑是高速電鍍的重要影響因素。在優(yōu)化控制條件下,對(duì)厚徑比為6.4:1的通孔(Φ=0.25 mm)進(jìn)行電鍍實(shí)驗(yàn),并對(duì)其進(jìn)行了鍍層性能測(cè)試,鍍液的均鍍能力能達(dá)到80%以上,孔徑的微觀形貌無瑕疵。將這一參數(shù)用于其他厚徑比的通孔電鍍,也得到了較好的結(jié)果。最后通過改變電流密度和攪拌強(qiáng)度,研究了它們?cè)诟咚匐婂冎械淖饔�。提高電流密度雖然能加快銅沉積速率,但會(huì)降低鍍液的均鍍能力;攪拌能夠?qū)﹃帢O表面?zhèn)髻|(zhì)產(chǎn)生一定影響,從而改善電流分布的均勻性。
[Abstract]:Metal copper has good electrical conductivity and thermal conductivity, and its coating can be used to realize the metallization of the hole of printed circuit board. With the rapid development of electronic industry, the size of printed circuit board (PCB) is decreasing and the performance requirement is increasing. This requires that the lines on the plate are finer, the ratio of thickness to diameter of the through hole is higher, and the stability of the coating is better. The increase of thick-diameter ratio reduces the dispersion ability of plating solution and increases the difficulty of pore metallization. In addition, with the increasing demand of PCB, it is necessary to increase the current density, shorten the electroplating time, and adopt high-speed electroplating process, thus increasing the concentration polarization in different areas of PCB. This paper presents a greater challenge to copper plating on printed circuit boards. At present, through the new development of electroplating additives to improve the plating ability of electroplating solution, can meet the increasing requirements of copper plating. Based on the mechanism of additives, a new method for evaluating the properties of additives has been established, and the accuracy of the method has been verified by experiments. The cyclic voltammetric stripping method can be used to qualitatively analyze and quantitatively analyze the inhibitors, and their performance differences can be judged according to the similarity of cyclic voltammetry curves of different inhibitors. By comparing the cyclic voltammetry curve with the standard curve, the concentration of inhibitor in the bath can be calculated. The performance of electroplated copper leveling agent can be evaluated by chronopotentiometry. The greater the negative shift of copper deposition potential, the greater the influence of leveling agent on deposition potential, the better the leveling performance is. After adding leveling agent, if the range of negative shift of potential exceeds 30 millivolts, it can be further tested, and the inferior leveling agent is eliminated for the first time by this method. In the electroplating process, the redox reaction will take place in the plating bath, and the electric energy will be consumed in competition with the copper ion deposition reaction, and the current efficiency of the electroplating copper will be reduced, and the reduction of current efficiency will be different from that of the plate surface and the hole. To achieve the purpose of improving the uniform plating ability of plating bath. In this paper, ferric sulfate and p-benzoquinone were added to the bath respectively. The effects of these compounds on the properties of high speed copper plating bath were studied. The results show that the average plating ability of electroplating solution will not be changed by trace iron ion. P-benzoquinone can realize the continuous conversion of oxidizing state and reducing state under the plating bath, which affects the current efficiency and improves the plating ability of the plating bath, so it can be used in the electroplating process of copper. The adsorption state of organic additives on printed circuit board is different under different electroplating conditions. In this paper, the optimum experiment design of the important composition ratio of the plating bath is carried out, and a group of plating parameters that accord with the high speed electroplating copper is obtained, and it is found that the brightener is an important influence factor of the high speed electroplating. Under the optimized control condition, the through hole (桅 = 0.25 mm) with a thickness to diameter ratio of 6.4: 1 was electroplated. The coating performance was tested. The average plating ability of the plating solution was over 80%, and the pore size was flawless. This parameter has been applied to other through hole electroplating with thick-diameter ratio, and good results have been obtained. Finally, by changing the current density and stirring intensity, the role of them in high-speed electroplating was studied. Although increasing the current density can accelerate the deposition rate of copper, it will reduce the average plating ability of the plating bath, and stirring can affect the mass transfer on the cathode surface to some extent, thus improving the uniformity of the current distribution.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TQ153.14
本文編號(hào)：2304090
[Abstract]:Metal copper has good electrical conductivity and thermal conductivity, and its coating can be used to realize the metallization of the hole of printed circuit board. With the rapid development of electronic industry, the size of printed circuit board (PCB) is decreasing and the performance requirement is increasing. This requires that the lines on the plate are finer, the ratio of thickness to diameter of the through hole is higher, and the stability of the coating is better. The increase of thick-diameter ratio reduces the dispersion ability of plating solution and increases the difficulty of pore metallization. In addition, with the increasing demand of PCB, it is necessary to increase the current density, shorten the electroplating time, and adopt high-speed electroplating process, thus increasing the concentration polarization in different areas of PCB. This paper presents a greater challenge to copper plating on printed circuit boards. At present, through the new development of electroplating additives to improve the plating ability of electroplating solution, can meet the increasing requirements of copper plating. Based on the mechanism of additives, a new method for evaluating the properties of additives has been established, and the accuracy of the method has been verified by experiments. The cyclic voltammetric stripping method can be used to qualitatively analyze and quantitatively analyze the inhibitors, and their performance differences can be judged according to the similarity of cyclic voltammetry curves of different inhibitors. By comparing the cyclic voltammetry curve with the standard curve, the concentration of inhibitor in the bath can be calculated. The performance of electroplated copper leveling agent can be evaluated by chronopotentiometry. The greater the negative shift of copper deposition potential, the greater the influence of leveling agent on deposition potential, the better the leveling performance is. After adding leveling agent, if the range of negative shift of potential exceeds 30 millivolts, it can be further tested, and the inferior leveling agent is eliminated for the first time by this method. In the electroplating process, the redox reaction will take place in the plating bath, and the electric energy will be consumed in competition with the copper ion deposition reaction, and the current efficiency of the electroplating copper will be reduced, and the reduction of current efficiency will be different from that of the plate surface and the hole. To achieve the purpose of improving the uniform plating ability of plating bath. In this paper, ferric sulfate and p-benzoquinone were added to the bath respectively. The effects of these compounds on the properties of high speed copper plating bath were studied. The results show that the average plating ability of electroplating solution will not be changed by trace iron ion. P-benzoquinone can realize the continuous conversion of oxidizing state and reducing state under the plating bath, which affects the current efficiency and improves the plating ability of the plating bath, so it can be used in the electroplating process of copper. The adsorption state of organic additives on printed circuit board is different under different electroplating conditions. In this paper, the optimum experiment design of the important composition ratio of the plating bath is carried out, and a group of plating parameters that accord with the high speed electroplating copper is obtained, and it is found that the brightener is an important influence factor of the high speed electroplating. Under the optimized control condition, the through hole (桅 = 0.25 mm) with a thickness to diameter ratio of 6.4: 1 was electroplated. The coating performance was tested. The average plating ability of the plating solution was over 80%, and the pore size was flawless. This parameter has been applied to other through hole electroplating with thick-diameter ratio, and good results have been obtained. Finally, by changing the current density and stirring intensity, the role of them in high-speed electroplating was studied. Although increasing the current density can accelerate the deposition rate of copper, it will reduce the average plating ability of the plating bath, and stirring can affect the mass transfer on the cathode surface to some extent, thus improving the uniformity of the current distribution.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TQ153.14
【參考文獻(xiàn)】
相關(guān)期刊論文 前3條
1 ;Preparation and characterization of molybdenum powders with copper coating by the electroless plating technique[J];Rare Metals;2008年04期
2 李雪春;印制電路板的電鍍銅技藝[J];印制電路信息;2004年05期
3 陳彥青;高厚徑比多層板的電鍍控制[J];印制電路信息;2001年11期
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