201016083 九、發明說明： 【發明所屬之技術領域】 本發明侧於—種電路板齡’ _是有_-種可避免產生 伽凡尼腐蝕現象的微蝕方法。 【先前技術】 印刷電路板(printed circuit board，PCB)是電子元件的支撐體，是 ❹電子元器件線路連接的提供者。現今印刷電路板係利用其上的= 導線圖案來電連結各個電子元件’目前銅導線職的製作步驟一 般需經過在電路板上錢銅膜、形成圖案化光阻、對銅膜進行侧 處理以及去除絲。在完成崎線㈣之後，依序料經過壓合、 鑽孔、鍍通孔、形成綠漆以及金屬表面處理，其中一般常見的金 屬表面處理的方式有噴錫(HotAirLeveUng，HAL)、電錄錄金、化 學錄金、直接金、化學錫、化學銀以及形成有機保焊劑(〇屯滅201016083 IX. Description of the invention: [Technical field to which the invention pertains] The present invention is a method of micro-etching which avoids the occurrence of galvanic corrosion. [Prior Art] A printed circuit board (PCB) is a support for electronic components and is a provider of 线路 electronic component wiring connections. Nowadays, printed circuit boards use the = wire pattern on them to electrically connect various electronic components. At present, the manufacturing steps of the copper wire are generally carried out by using a copper film on the circuit board, forming a patterned photoresist, laterally processing the copper film, and removing wire. After the completion of the Saki line (4), the material is pressed, drilled, plated through holes, green paint and metal surface treatment. The common metal surface treatment methods are hot air (HotAirLeveUng, HAL), electric recording Gold, chemical gold, direct gold, chemical tin, chemical silver and the formation of organic soldering agent (annihilation
Solder Preservative，OSP) °Solder Preservative, OSP) °
Q 其中以電_金、化學鎳金、直接金三種金屬表面處理為例， 在完成金屬表面處理之後，從外部的表面上觀察得知，該電路板 之。卩刀的銅導線上覆有綠漆，而一部分的銅導線上則覆有金 層’而剩餘部分的銅導線則是裸露出來，裸露的銅導線因為接觸 到工氣’即會在其表面形成—層極薄的氧化銅。_ ’此形成氧 •化銅的部分，岐後續要以有機保焊紐蓋的區域。 因此’在進行有機赌劑製程之前’需先對電路板進行紐處理， 201016083 其目的在於絲銅導絲面的髒汗和氧化銅，並且將銅導線表面 粗化以利賴有機糾臟膜，f知技射所制的顯液皆為 酸性系統包含：過硫酸納(SPS)/稀硫酸水溶液、硫酸/雙氧水水溶 液以及稀硫酸水溶液。進行微餘製程時，係將電路板利用上述的 微錄淋沖’而在淋沖㈣程，首先氧化銅會先被去除，露出鋼 導線表面，之後，電路板的鑛金層和裸露的銅導線會同時接觸微 蝕液，如此一來，即會產生伽凡尼腐蝕(galvanicc〇rr〇si〇n)現象， ❹伽凡尼雜現祕指具林同氧化電位的金屬在電解液中，會有 電位差而產生電化學反應，其中由氧化電位高的（如辞、鐵等） 形成陽極，氧化電位低的作為陰極，而陽極在電化學反應時會 形成離子而溶於電解液中，因此陽極金屬會逐漸被腐蚀。在微钮 製程時，所產生伽凡尼腐蝕現象，係由裸露的銅導線作為陽極， 鍍金層作為陰極，陽極的導線會和微蝕液中的活化物生成有機銅 錯化物，溶於微蝕液中，並拋出兩個電子，而電子將經過線路， 使微餘液中的銅離子還原而沉積在陰極的鍍金層上’造成鍍金層 ® 顏色變深，並且裸露的銅導線逐漸變細，更甚者，則產生斷線現 象。 由此可知，目前業界急需一種改良的微蝕方法，在去除氧化銅 的同時，可以避免電路板上的銅導線發生伽凡尼腐蝕現象。 【發明内容】 有鑑於此，本發明提出一種新穎的電路板微蝕方法，特別是使 201016083 用在形成有機保焊劑前的預處理步驟，其可以有效預防銅導線因 伽凡尼效應而腐钱。 根據本發明之一實施例，本發明提供避免伽凡尼腐蝕效應的電 路板微触方法，包含：首先，提供一電路板，其上定義有一銅導 線圖案，其中該銅導線圖案之一第一區域覆有一金屬層，該銅導 線圖案之一第二區域覆有一銅氧化物；以及使用一酸性電解水微 蝕該電路板，以去除該銅氧化物，同時避免該第二區域的該銅導 線圖案產生伽凡尼腐餘現象。根據本發明之一實施例，上述之酸 性電解水的pH值係介於2.0至3.5之間。 為讓本發明之上述目的、特徵、和優點能更明顯易僅，下文特 舉一實施方式，並配合所附圖式，作詳細說明如下。然而如下之 -實施方式與圖式僅供參考與說_，並_來對本發明加以限 制者。 【實施方式】 第1圖所繪*的是本㈣之電路板侧姻。第2崎示的是本 發明有機保焊劑的預處理步驟之流程圖。 如第1圖所不，首先提供一電路板10，電路板10包含一基材 12導電通孔16貫穿基材I2、以及-圖案化之銅導線圖案14。 在銅導線圖案14之第一區域A之表面覆有-金屬層20，例如以 201016083 電鑛鎳金槪賴金為本實_之說明，其巾金制μ分為一第 二金屬層2〇b和-第-金屬層咖，第二金屬層為一鍵錄層， 而第-金屬層20a為-鑛金層，然在其他未纷示的實施例中該 金屬層20亦可以為單—金屬層結構，例如金、銀、料。而銅導 _案14之第二區域B則為裸露的銅導線’但由於曝露在空氣 中，因此’在第二區域B的銅導線圖案14很快就會形成一氧化銅 22。此外，在第一區域A的銅導線圖# 14和部分第二區域b的 銅導線圖案14狀導電通孔16電連結，句話說，電路板ι〇已 經元成鑽孔、鍍通孔、形成圖案化銅導線 理的製程，輪曙要進行咖焊獅之前 驟。 如第2圖所示’形成有機保焊膜之前，電路板1()首先需經過 酸性脫脂3G財除表面上的雜，接著進行水洗％以洗淨酸性 脫脂劑’然後再進行微減理34，以去除前述的氧化銅22，接著 © 再進入水洗36以去除微餘液，之後進行預浸38和水洗4〇，即可 進入有機保焊劑製程42。有別於傳統製程，本發明的特徵在於微 蝕處理34中係使用酸性電解水作為微蝕液來淋沖電路板1〇。 第3圖所繪示的是微蝕槽之示意圖。請同時參閱第丨囷和第3圖， 一徵蚀槽50承裝酸性電解水52作為微钱液，電路板1〇經由一輸 送帶53送入微姓槽50中，在徵银槽5〇中的酸性電解水％可經 由泵供應給徵蝕槽50的喷灑裝置54，利用喷灑裝置54將酸性電 解水52淋沖在電路板1〇上，而酸性電解水的溫度則保持在 201016083 45±5°C，如此一來，即可去除電路板10上的氧化銅22，此外，也 可以利用浸泡的方式來去除氧化銅22。根據本發明之一實施例， 其中該酸性電解水52的氧化還原電位介於mv之 間，而pH值介於2〜3.5之間。 由於前述適當操作條件的酸性電解水主要會對氧化銅產生反 應，而幾乎不會溶钱銅表面。因此，在去除氧化銅後而裸露的銅 ❹導線圖案不會被進-步被溶钱，如此一來，伽凡尼腐蚀效應即被 抑止，而銅斷線現象以及在鍍金層產生銅還原的現象則可以被有 效避免。值得注意的是：雖然上述實施例是以經過鎳金表面處理 的電路板為例，但本發明之酸性電解水，不僅對於鎳金表面處理 後的電路板，有防止伽凡尼腐蝕效應的效果，對於經過其它金屬 表面處理的電路板，使得電路板表面上有鍍金、鍍銀、鍍鉑或是 其它氧化電位較銅為低的金屬的情況，皆可以使用本發明之酸性 電解水來進行微触，達到去除氧化銅和避免伽凡尼腐蝕效應的目 〇 的。 上述的酸性電解水52 ’係利用陽極與陰極之間具有離子穿透性 隔膜的電解槽，進行純水電解所獲得，由於純水的導電性差，因 此在純水中會加入少量的氣化鈉。根據本發明之一實施例，要生 成酸性電解水的起始預電解時間介於5〜1〇分鐘之間，電解電壓介 於200〜240伏特(V)之間。 201016083 第4a圖至第(5b圖為分別使用傳統微蝕液和本發明之酸性電解 水微钮電路板之電子顯微鏡檢測圖。 第4a圖中的電路板係經由本發明之酸性電解水重覆微蝕三 次’第4b®為第4a圖中的電路板之部分放大圖，如第处圖所示， 電路板上的銅導線圖案皆完整。第5a圖中的電路板係經由傳統微 蝕液重覆微餘二次’第5b圖為第5a圖中的電路板之部分放大圖。 如第5b圖所示，相較於4b圖，第5b圖中的銅導線圖案有數個明 11 顯的斷線部位。 第6a圖中的電路板係經由本發明之酸性電解水重覆微蝕三 次’如第6a圖所示，電路板上的銅導線圖案皆完整。第汍圖中 的電路板係經由傳統微餘液重覆微蝕三次，如第6b圖所示，相較 於6a圖’第％圖中的銅導線圖案有數個用方框標示處，顯示被 伽凡尼腐姓效應侵餘的部位。由上述檢測圖可知，即使用酸性電 〇 解水微蝕三次後，銅導線圖案依然可以維持完整，所以本發明之 酸性電解水的確可以成功的避免伽凡尼腐钱效應。 有別於習知技術，本發明採用酸性電解水取代過硫酸納稀硫酸 水溶液、硫酸/雙氧水水溶液以及稀硫酸水溶液作為微钱液，根據 中請人的長期研究發現，使用酸性電解水來微蚀經過錄金表面處 理製程的電路板’不但可以有效的將氧化銅去除，更可以避免在 清洗過程中’伽凡尼腐賊象的發生。因為具有射操作條件的 201016083 酸性電解水主要會對氧化銅產生反應，使得氧化銅溶出變成銅離 子’而幾乎不會溶蝕銅表面。因此，在去除氧化銅後而裸露的銅 導線圖案不會被溶银，如此一來，伽凡尼腐蝕效應即被抑止，而 銅斷線現象以及在ϋ金層產生賴原的現㈣可以被有效避免。 以上所述僅為本發明之一實施例，凡依本發明申請專利範圍 所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。Q In the case of three kinds of metal surface treatments of electric gold, chemical nickel gold, and direct gold, after the metal surface treatment is completed, the circuit board is observed from the external surface. The copper wire of the file is covered with green lacquer, while the part of the copper wire is covered with a gold layer' while the remaining part of the copper wire is exposed. The exposed copper wire will form on the surface due to contact with the working gas. - Very thin layer of copper oxide. _ 'This forms part of the oxygen-copper, which is followed by the area covered by the organic soldering cap. Therefore, 'Before the organic gambling process, 'the board needs to be processed first, 201016083. The purpose is to the dirty sweat and copper oxide on the wire guide surface, and the surface of the copper wire is roughened to benefit the organic smear film. The known liquids produced by the company are all acidic systems including: sodium persulfate (SPS) / dilute sulfuric acid aqueous solution, sulfuric acid / hydrogen peroxide aqueous solution and dilute sulfuric acid aqueous solution. When performing the micro-remaining process, the board is made of the above-mentioned micro-recording and rinsing, and in the first step, the copper oxide is first removed to expose the surface of the steel wire, and then the gold layer of the circuit board and the bare copper. The wire will contact the micro-etching solution at the same time, so that the phenomenon of galvanicc〇rr〇si〇n will occur, and the gamma-Vanni is the metal with the oxidation potential in the electrolyte. There is a potential difference to generate an electrochemical reaction, in which an anode is formed by a high oxidation potential (such as rhetoric, iron, etc.), and a low oxidation potential is used as a cathode, and an anode forms an ion in an electrochemical reaction and dissolves in the electrolyte. The anode metal is gradually corroded. In the micro-button process, the Galvanic corrosion phenomenon is caused by the bare copper wire as the anode, the gold plating layer as the cathode, the anode wire and the activator in the micro-etching solution to form the organic copper complex, soluble in the micro-etching. In the liquid, and throwing two electrons, and the electrons will pass through the line, reducing the copper ions in the remnant and depositing on the gold plating layer of the cathode, causing the gold plating layer to become darker and the bare copper wire is tapered. And even worse, it is broken. It can be seen that there is an urgent need for an improved micro-etching method in the industry to avoid the occurrence of galvanic corrosion of copper wires on the circuit board while removing copper oxide. SUMMARY OF THE INVENTION In view of this, the present invention proposes a novel circuit board micro-etching method, in particular, 201016083 is used in a pre-treatment step before forming an organic soldering flux, which can effectively prevent copper wires from being corrupted due to the gamma-neon effect. . According to an embodiment of the present invention, the present invention provides a circuit board micro-touch method for avoiding a Galvanic corrosion effect, comprising: first, providing a circuit board having a copper wire pattern defined thereon, wherein the copper wire pattern is first The region is covered with a metal layer, a second region of the copper wire pattern is covered with a copper oxide; and the circuit board is microetched with an acidic electrolytic water to remove the copper oxide while avoiding the copper wire of the second region The pattern produces the phenomenon of gamma sin. According to an embodiment of the present invention, the acidic electrolyzed water has a pH of between 2.0 and 3.5. The above described objects, features, and advantages of the present invention will become more apparent from the following description. However, the following embodiments and drawings are for reference only and are intended to limit the invention. [Embodiment] The drawing of Fig. 1 is the side of the circuit board of this (4). The second schematic shows a flow chart of the pretreatment step of the organic solder resist of the present invention. As shown in Fig. 1, first, a circuit board 10 is provided. The circuit board 10 includes a substrate 12, a conductive via 16 extending through the substrate I2, and a patterned copper conductor pattern 14. The surface of the first region A of the copper wire pattern 14 is covered with a metal layer 20, for example, according to the description of 201016083 electro-nine nickel-gold ruthenium, and the towel gold-made μ is divided into a second metal layer 2〇 b and - the first metal layer, the second metal layer is a bond layer, and the first metal layer 20a is a -mine gold layer, but in other embodiments not shown, the metal layer 20 may also be single - Metal layer structure, such as gold, silver, material. The second region B of the copper conductor 14 is a bare copper wire 'but due to exposure to air, the copper wire pattern 14 in the second region B will soon form copper oxide 22. In addition, the copper wire pattern #14 of the first region A and the copper wire pattern 14-shaped conductive via hole 16 of the portion of the second region b are electrically connected. In other words, the circuit board has been drilled, plated, and formed. The process of patterning copper wire is to be done before the rim is to be welded. As shown in Fig. 2, before the formation of the organic solder mask, the board 1 (1) first needs to be acid degreased to remove impurities on the surface, followed by water washing to wash the acidic degreaser' and then micro-reduction 34. To remove the aforementioned copper oxide 22, and then into the water wash 36 to remove the residual liquid, followed by pre-dip 38 and water washing 4, the organic flux-preserving agent process 42 is entered. Different from the conventional process, the present invention is characterized in that the micro-etching treatment 34 uses acidic electrolyzed water as a micro-etching liquid to rinse the circuit board. Figure 3 is a schematic view of a microetching trench. Please refer to the third and third figures at the same time. A corrosion tank 50 carries the acidic electrolyzed water 52 as a micro-money liquid, and the circuit board 1〇 is sent into the micro-slot 50 through a conveyor belt 53 in the levy tank 5 The acidic electrolytic water % can be supplied to the spraying device 54 of the etching tank 50 via a pump, and the acidic electrolyzed water 52 is sprayed on the circuit board 1 by the spraying device 54, while the temperature of the acidic electrolyzed water is maintained at 201016083 45 ±5 ° C, in this way, the copper oxide 22 on the circuit board 10 can be removed, and the copper oxide 22 can also be removed by immersion. According to an embodiment of the invention, the acidic electrolyzed water 52 has an oxidation-reduction potential between mv and a pH between 2 and 3.5. The acidic electrolyzed water due to the aforementioned appropriate operating conditions mainly reacts to the copper oxide, and hardly dissolves the copper surface. Therefore, the exposed copper beryllium wire pattern after the removal of the copper oxide is not further dissolved, so that the Galvanic corrosion effect is suppressed, and the copper wire breakage phenomenon and the copper reduction in the gold plating layer are caused. Phenomena can be effectively avoided. It is worth noting that although the above embodiment is exemplified by a nickel-gold surface treated circuit board, the acidic electrolyzed water of the present invention has an effect of preventing the Galvanic corrosion effect not only on the nickel-gold surface-treated circuit board. For the circuit board treated with other metal surfaces, if the surface of the circuit board is plated with gold, silver plated, platinized or other metal having a lower oxidation potential than copper, the acidic electrolyzed water of the present invention can be used for micro-application. Touch, to achieve the goal of removing copper oxide and avoiding the Galvanic corrosion effect. The above-mentioned acidic electrolyzed water 52' is obtained by electrolyzing electrolytic cells having an ion-permeable membrane between the anode and the cathode, and pure water is electrolyzed. Since pure water has poor conductivity, a small amount of sodium carbonate is added to the pure water. . According to an embodiment of the present invention, the initial pre-electrolysis time for generating the acidic electrolyzed water is between 5 and 1 minute, and the electrolysis voltage is between 200 and 240 volts (V). 201016083 4a to 5b (5b are electron micrographs of the conventional microetching liquid and the acidic electrolyzed water micro-button circuit board of the present invention, respectively. The circuit board in Fig. 4a is repeated by the acidic electrolyzed water of the present invention. Micro-etching three times '4b® is a partial enlarged view of the circuit board in Figure 4a. As shown in the figure above, the copper wire pattern on the circuit board is complete. The circuit board in Figure 5a is via traditional micro-etching liquid. Figure 5b is a partial enlarged view of the circuit board in Figure 5a. As shown in Figure 5b, the copper wire pattern in Figure 5b has several distinct features compared to Figure 4b. The broken part. The circuit board in Fig. 6a is micro-etched three times by the acidic electrolyzed water of the present invention. As shown in Fig. 6a, the copper wire pattern on the circuit board is complete. The circuit board in Fig. Repeated micro-etching three times through the traditional micro-remaining liquid, as shown in Figure 6b, compared with the copper wire pattern in Figure 6A, the number of copper wire patterns is marked with a number of squares, indicating that the Gaffini rot effect is invaded. The position of the above test chart shows that after using the acid electric enthalpy to dissolve the water three times, The wire pattern can still be maintained intact, so the acidic electrolyzed water of the present invention can successfully avoid the gamma sin effect. Unlike the prior art, the present invention uses acidic electrolyzed water instead of sodium persulfate aqueous solution of sulfuric acid, sulfuric acid/hydrogen peroxide. Aqueous solution and dilute sulfuric acid aqueous solution are used as micro-money liquid. According to the long-term research of Zhongzhong people, the use of acidic electrolyzed water to micro-etch the circuit board after gold-plated surface treatment process can not only effectively remove copper oxide, but also avoid cleaning. In the process, the occurrence of 'Gamni rot thief elephant'. Because of the operating conditions of 201016083, the acidic electrolyzed water mainly reacts to copper oxide, so that the copper oxide dissolves into copper ions' and hardly erodes the copper surface. Therefore, it is removed. After the copper oxide, the exposed copper wire pattern is not dissolved by silver, so that the Galvanic corrosion effect is suppressed, and the copper wire breakage phenomenon and the current (4) in the sheet metal layer can be effectively avoided. The foregoing is only one embodiment of the present invention, and the equal variations and modifications made by the scope of the patent application of the present invention are Also belong the present invention.
【圖式簡單說明】 第1圖所緣示的是本發明之電路板側視圖。 第2 _示的是本發明有機保焊劑的預處理步驟之流程圖。 第3圖所緣示的是本發明之微蝕槽示意圖。 圖帛6b圖為为別使用傳統微餘液和本發明之酸性電解水 微触電路板之電子顯微鏡檢測圖。 〇 【主要元件符號說明】 10 電路板 12 基材 14 銅導線圖案 16 導電通孔 20b 第二金屬層 20a 第一金屬層 22 氧化鋼 30 酸性脫脂 32 水洗 34 微姓處理 36 水洗 38 預浸 40 水洗 42 有機保焊劑製程 11 201016083 50 徵蝕槽 52 酸性電解水 53 輸送帶 54 喷灑裝置 20 金屬層 ΟBRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a circuit board of the present invention. The second embodiment shows a flow chart of the pretreatment step of the organic solder resist of the present invention. Figure 3 is a schematic view of the microetching tank of the present invention. Figure 6b is an electron microscopic inspection chart for the use of the conventional micro-remaining liquid and the acidic electrolyzed water micro-touch circuit board of the present invention. 〇【Main component symbol description】 10 Circuit board 12 Substrate 14 Copper conductor pattern 16 Conductive through hole 20b Second metal layer 20a First metal layer 22 Oxidized steel 30 Acid degreasing 32 Washed 34 Micro-processing 36 Washing 38 Pre-dipping 40 Washing 42 Organic flux soldering process 11 201016083 50 Erosion tank 52 Acidic electrolysis water 53 Conveyor belt 54 Spraying device 20 Metal layer Ο
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