201108903 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種挾著絕緣層$ 線’並經由導通孔之層間連接部而^複數個電路配 印刷電路板及其製造方法。 各θ之電路配線的 【先前技術】 以往，為了在多層印刷電路板 '緣之各電路配線，係貫穿絕緣層二 == 之導通孔。該層間連接時係採用在乂又有導電材料 内填充銅電鍍或導電性膏的方法^於絕緣層之導通孔 廣間連接方法具有製造時對環境寺^是使用導電性膏之 法簡便的優點。 負擔小，且製造方 如第3圖所示，該層間連 緣層1的兩面貼合有鋼帛2 轉聚醯亞胺等之絕 鋼笛2上貼合PET等== 兩:-板4之表面側的 射光等在銅笛2之指定Γ置开成^三八圖），使用，雷 夏办成導通孔笛二Rfsi、,, 時，亦有依序在遮光膜5盘^ 一 "。 ^ /、銅泊2及絕緣層1中形成開孔 部=孔的方法，或是同時形成貫穿孔之方法。其次， 在導通孔6内填充導電性膏8並使 圖）。之後，剝離遮光膜5 (第二1弟一 ^ 、弟一 D圖），進行熱擠壓，而 形成導電性貧8之層間連接構造。其次，在銅箱2,3上塗 布或貼合無圖不之抗姓材料，將指定之電路圖案曝光，除 告電路圖案部以外之抗蝕劑，在㈣2, 3上形成指定之電Η 201108903 路圖案，而完成導電性膏8之層間連接構造（第三£圖）。 其他’如專利文獻i所揭示，亦有在黏合片之兩面貼 合薄膜’藉由雷射光形成貫穿孔，在該貫穿孔中填充導電 性貧後，剝離薄膜’在黏合片之兩面貼合金屬落並實施熱 擠壓，而連接兩面之金屬箔的層間連接方法。 但疋’導電性膏係藉由樹脂中之銀及銅等各導電性粒 子的接觸而產生導電性者，會發生基板上之電路的金屬箱 與填充於貫穿孔之導電性膏的接觸面積縮小，以及因接觸 狀態而電阻值變大的情況。再者，由於近年來電路結構之 馬密度化及小型化，導致接觸部分之面積極小，而電路電 阻增加。此外’因熱循環等之環境變化，而在基板上發生 反覆之應力時’會有損害導電性膏與電路用金屬R接 觸’導致接觸電阻增加，而無法獲得良好之導電特性的情 況。特別是伴隨多屬電路基板等之電路的微細化，電路之 金屬謂變薄且雜也變小’因此與導電性膏之接觸面積減 少，電阻增大’以致電性導通之可靠性降低。 因此，專利文獻2 +揭示之層間連接方法係提出··在 设有形成電路之金屬㈣絕緣層之基板中形成貫穿孔 由填充於該貫穿孔内之導電性^電性 :BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit-bonded printed circuit board and a method of manufacturing the same according to an interlayer connection portion of a via hole. [Circular Technology] of the θ Circuit Wiring In the related art, in order to route the circuits of the multilayer printed circuit board, the through holes of the insulating layer 2 == are penetrated. The interlayer connection is a method of filling a copper plating or a conductive paste in a conductive material, and a method of connecting the conductive vias to the insulating layer, and the method of using the conductive paste for the environment is simple. . The burden is small, and the manufacturer has the same as shown in Fig. 3, and the two sides of the interlaminar layer 1 are bonded with a steel crucible 2, a bismuth iodide or the like, and the PET is attached to the PET 2, etc. == Two: - Plate 4 The surface of the surface of the light, etc. in the design of the copper flute 2 set into ^ 38 figure), use, Lei Xia into the conduction hole flute two Rfsi,,, when there are also in the light film 5 disk ^ a ; ^ /, copper poking 2 and the method of forming the opening portion = hole in the insulating layer 1, or the method of forming the through hole at the same time. Next, the conductive paste 8 is filled in the via hole 6 and patterned. Thereafter, the light-shielding film 5 (the second one, the first one, and the second one) is peeled off, and hot extrusion is performed to form an interlayer connection structure of electrically conductive lean. Next, the copper box 2, 3 is coated or bonded with the anti-surname material, and the specified circuit pattern is exposed, and the resist other than the circuit pattern portion is formed on (4) 2, 3 to form the designated electric power 201108903 The road pattern is completed, and the interlayer connection structure of the conductive paste 8 is completed (third map). Others, as disclosed in Patent Document i, there is also a film which is bonded to both sides of the adhesive sheet. The through hole is formed by the laser light. After the conductive hole is filled in the through hole, the peeling film is attached to the metal on both sides of the adhesive sheet. Falling and performing hot extrusion, and joining the two layers of the metal foil interlayer connection method. However, when the conductive paste is electrically conductive by contact of each of the conductive particles such as silver and copper in the resin, the contact area between the metal case of the circuit on the substrate and the conductive paste filled in the through hole is reduced. And the case where the resistance value becomes large due to the contact state. Furthermore, due to the recent densification and miniaturization of the circuit structure, the surface of the contact portion is actively small, and the circuit resistance is increased. In addition, when the stress is reversed on the substrate due to environmental changes such as thermal cycling, the contact between the conductive paste and the circuit metal R may be impaired, resulting in an increase in contact resistance and inability to obtain good electrical conductivity. In particular, with the miniaturization of circuits such as circuit boards, the metal of the circuit is thin and the amount of impurities is small. Therefore, the contact area with the conductive paste is reduced, and the resistance is increased, and the reliability of the call-through is lowered. Therefore, the interlayer connection method disclosed in Patent Document 2+ proposes that a through hole is formed in a substrate provided with a metal (four) insulating layer forming a circuit, and electrical conductivity filled in the through hole is:
面之金屬領者，且係在位於貫穿 土板表U 形成凹面，使填充之導電性緣的金屬箱之端面 以確保接觸狀態者。4_狀接觸面積增大， 此外’專利文獻3所揭示之層間連 孔中填充有用於層間導通之導電性膏的兩面印：2 .201108903 形成電路的銅箔之一面，貼合遮光膜作為印刷用遮罩。而 後，形成導通孔時，首先藉由雷射照射，而在該遮光膜上 開設孔徑比導通孔徑大之開孔部。其次，藉由雷射光在其 開孔部内形成直徑比其開孔部小之導通孔。此時，與表面 之銅箔一起亦在絕緣層中形成穿透孔，而使背面之銅箔露 出於導通孔内。之後，在導通孔内填充導電性膏，剝離遮 光臈，將填充之導電性膏實施熱擠壓使其硬化。再者，在 表面之銅箔上塗布抗蝕劑，將指定之電路圖案曝光，蝕刻 除去電路圖案以外之抗蝕劑，而形成電路之兩面印刷電路 板的製造方法。該製法係首先在遮光膜上形成大的開孔， 並在其内側形成直徑小之導通孔，以增大形成電路之銅箔 與導通孔内之導電性膏的接觸面積。 仁疋先如之方法會有藉由雷射光所形成之遮光膜的 開孔部周緣部隆起，遮光膜之孔徑比導通孔徑小，而阻礙 導電性膏之填充的問題。此因遮光膜之開孔狹窄時，阻礙 分散於導電膏中之金屬粒子的2次凝聚粒子在填充製程中 從開孔部侵入導電性膏。再者，亦可能在開孔部之隆起部 周圍形成膏淤積等’而阻礙向開孔部内填充。 此外，上述專利文獻1所揭示之層間連接構造，有在 將導電性膏填充於貫穿孔後，貼合金㈣之製程，因此製 程複雜，藉由金屬箔形成電路之接端面部時，不易與層門 連接之導電性膏的位践準，因而不㈣用於微細電ς圖 案之電路板。此外，專利文獻2所揭示之層間連接方法， 在表面之金屬箔的端面形成凹部之製程困難，而無法適用 201108903 ' 於薄的金屬箔及微細之電路圖案。再者，專利文獻3所揭 示之層間連接方法，係於藉由雷射光在遮光膜上形成開孔 後，藉由雷射光將比其孔徑小之孔徑的孔形成於金屬箔 上，進一步亦在絕緣層中藉由雷射光形成貫穿孔。之後， 填充導電性膏而電性連接表面與背面之金屬箔，其製程繁 多，且為了抑制之後的雷射光對形成於遮光膜之當初的開 孔造成影響等，其開孔較大，而無法適用於微細之電路圖 案。 <先前技術文獻> <專利文獻> [專利文獻1]日本專利第2874581號公報 [專利文獻2]日本特開2003-188533號公報 [專利文獻3]曰本特開2007-281336號公報 【發明内容】 (發明所欲解決之問題） 本發明之課題為解決先前之前述各問題，而達成以下 之目的。亦即本發明之目的為提供一種確實進行導電膏之 層間連接，電阻低且連接可靠性亦高之印刷電路板及其製 造方法。 (解決問題之手段） 解決前述課題之手段如下。亦即， < 1 >一種印刷電路板之製造方法，該印刷電路板具 有：絕緣層；電路配線，其係形成於前述絕緣層之兩面， 6 201108903 並由金屬箔構成；及導電性膏，其係填充於前述絕緣層中 所設之導通孔，而電性連接形成於前述絕緣層之兩面的各 電路配線；其特徵為：在前述絕緣層之一方侧的電路配線 表面貼合遮光膜，在貼合前述遮光膜之面照射第1雷射光， 而在前述遮光膜及前述絕緣層之一方側的電路配線上形成 開孔部，並藉由光點徑比形成於前述遮光膜之開孔部周緣 隆起部的稜線之直徑大的第2雷射光，在前述絕緣層上形 成前述導通孔，並在前述導通孔中填充前述導電性膏，而 電性連接前述各電路配線。 <2>如前述<1>印刷電路板之製造方法，其中第2 雷射光之光點徑比第1雷射光大，且光能密度比第1雷射 光小。 <3>如前述<1>或<2>印刷電路板之製造方法，其 中第1雷射光在遮光膜上形成之開孔部的直徑，比絕緣層 之一方侧的電路配線之開孔部的直徑大。 <4>如前述<1>至<3>中任一項印刷電路板之製 造方法，其中導通孔係將具有藉由第1雷射光所形成之開 孔部的絕緣層之一方侧的電路配線作為遮罩，藉由第2雷 射光貫穿絕緣層而形成。 <5>如前述<4>印刷電路板之製造方法，其中藉由 第2雷射光形成導通孔後，除去膠渣，在前述導通孔内填 充導電性膏，並進行乾燥及熱擠壓，而電性連接各電路配 線。 <6>—種印刷電路板，其具有：絕緣層；電路配線，[ 201108903 其係形成於前述絕緣層之兩面，並由金屬箔構成；及導電 性膏，其係填充於前述絕緣層中所設之導通孔，而電性連 接形成於前述絕緣層之兩面的各電路配線；其特徵為：在 前述絕緣層之一方侧的電路配線表面貼合遮光膜之狀態 下，藉由照射第1雷射光而形成前述絕緣層之一方側的電 路配線之開孔部，藉由光點徑比藉由前述第1雷射光而形 成於前述遮光膜之開孔部周緣隆起部的稜線之直徑大的第 2雷射光，照射於前述絕緣層之一方側的電路配線之開孔部 而形成前述導通孔，前述導電性膏堆疊於藉由前述第2雷 射光所形成之前述導通孔周緣部的前述遮光膜開孔部之内 側部分的前述電路配線表面。 <7>如前述<6>之印刷電路板，其中絕緣層係聚醯 亞胺，且具有在前述絕緣層之兩面貼合銅II之兩面銅箔板。 (發明之效果） 採用本發明之印刷電路板及其製造方法時，可確實將 導電性膏填充於連接印刷電路板之各層電路的貫穿孔内， 導電性膏與形成電路之金屬箔的接合面積及接合強度提 高。藉此，導電性膏之層間連接的電阻低，連接之可靠性 亦高，且對熱循環及熱衝擊等之電性連接的可靠性亦提 高。因而使電子機器之耐環境性能及耐用性提高，且成本 之增加亦少。 【實施方式】 (印刷電路板之製造方法） .201108903 本發明之印刷電路板的製造方法至少包含：遮光膜貼 合製程、開孔部形成製程、導通孔形成製程及導電性膏填 充製程，進一步包含依需要而適宜選擇之其他製程。 <遮光膜貼合製程> 前述遮光膜貼合製程係在絕緣層之一方側的電路配線 表面貼合遮光膜之製程。 一遮光膜一 前述遮光膜並無特別限制，可依目的而適宜選擇，例 ， 如為在PET膜上塗布黏合劑者等。 ' 前述遮光膜之疊層方法並無特別限制，可依目的而適 宜選擇，例如為真空疊層法等。 此外，由於前述遮光膜係直接貼合於未形成電路之銅 箔上，因此表面均勻，無凹凸及階差，可輕易且良好地貼 合。 一絕緣層一 前述絕緣層之材質只要具有絕緣性即可，並無特別限 制，可依目的而適宜選擇，不過，例如宜為聚醯亞胺。 • 前述絕緣層之厚度並無特別限制，可依目的而適宜選 - 擇。 一電路配線一 前述電路配線並無特別限制，可依目的而適宜選擇， 例如為金屬箔，其中以銅箔為宜。 <開孔部形成製程> 前述開孔部形成製程，係在貼合有遮光膜之面照射第1 [ s 9 201108903 雷射光，而在前述遮光膜及絕緣層之一方側的電路配線中 形成開孔部。 —第1雷射光一 前述第1雷射光並無特別限制，可依目的而適宜選擇， 不過，例如宜為準分子雷射等之UV雷射光。 <導通孔形成製程> 前述導通孔形成製程，係藉由光點徑比形成於遮光膜 之開孔部周緣隆起部的稜線之直徑大的第2雷射光，而在 前述絕緣層中形成前述導通孔之製程。 一第2雷射光一 前述第2雷射光並無特別限制，可依目的而適宜選擇， 例如為二氧化碳(C02)雷射光、YAG雷射等。另外，第2雷 射之光能密度宜比第1雷射小。 一形成於開孔部周緣隆起部的棱線一 隆起部係在遮光膜之開孔部周緣部鼓起的環狀。 前述所謂隆起部的棱線，係隆起部之頂點的連線。 前述稜線之直徑的測定方法並無特別限制，可依目的 而適宜選擇，例如為藉由使用顯微鏡之剖面觀察、表面觀 察的測定方法等。 <導電性膏填充製程> 前述導電性膏填充製程，係在導通孔中填充導電性 膏，而電性連接各電路配線之製程。 一導電性膏一 前述導電性膏只要是在熱可塑性樹脂中混合高熔點金 .201108903 屬與低熔點金屬之金屬粒子，並以隨後的加熱處理而合金 化者即可，並無特別限制，可依目的而適宜選擇。 前述高熔點金屬並無特別限制，可依目的而適宜選 擇，例如為至少包含銅之粒子（銅單體之粒子，或包含金、 銀、鋅及鎳中1個以上之金屬與銅的合金粒子）等。此外， 前述金屬粒子之表面亦可藉由電鍍等而被覆金、銀、鋅或 鎳、或此等之合金。前述金屬粒子之平均粒徑並無特別限 制，可依目的而適宜選擇，不過宜為約1 //m〜約10//m(例 如為6// m)。 前述低熔點金屬並無特別限制，可依目的而適宜選 擇，例如為錫或含錫合金（例如焊錫）之粒子等。 前述焊錫並無特別限制，可依目的而適宜選擇，例如 為錫一銅系焊錫、錫一銀糸焊錫、錫一銀一銅糸焊錫’或 此等中添加姻、辞、絲之任何一個以上，而進一步適宜混 合者等。 前述導電性膏之黏合劑用樹脂，只要係熱可塑性樹脂 即可，並無特別限制，可依目的而適宜選擇，例如為聚自旨、 聚烯烴、聚醯胺、聚醯胺亞胺、聚醚亞胺、聚苯醚、聚苯 硫化物、聚乙醇縮丁醛等之樹脂、其他為環氧樹脂、丙烯 酸樹脂等。 一導電性膏之填充方法一 前述導電性膏之填充方法並無特別限制，可依目的而 適宜選擇，不過例如為絲網印刷、喷射印刷等之印刷等的 方法。此外，亦可使用將剝離性之膜作為遮罩材料，藉由[s 11 201108903 擠壓而填充於導通孔之方法。 以下，就本發明之印刷電路板的一種實施形態，依據 第1圖及第2圖作說明。該實施形態之印刷電路板10係在 絕緣層12之兩面形成有由金屬箔之銅箔13, 14而構成的電 路配線13a, 14a。絕緣層12係由聚醯亞胺等之絕緣性基板 而構成，並在兩面貼合銅箔13, 14者。絕緣層12之表面與 背面的銅箔13, 14經由後述之製程形成指定之電路圖案， 而構成電路配線13a，14a。 絕緣層12中形成用於電性連接表面與背面之電路配線 13a，14a間的導通孔16，並藉由導電性膏18之層間連接構 件而連接表面與背面之電路配線13a，14a。 其次，就該實施形態之印刷電路板10的製造方法，依 據第1圖及第2圖作說明。首先如第1A圖所示，在將聚醯 亞胺等作為基板之兩面銅箔板22的形成有銅箔13之一側 面側貼合遮光膜24。 其次，在兩面銅箔板22上，從遮光膜24側照射準分 子雷射等之UV雷射光L1，而在遮光膜24中形成開孔26， 並且同時亦在銅箔13中形成開孔部28 (第1B圖）。此時， 在遮光膜24之開孔部26周緣部形成鼓起之環狀的隆起部 26a。該雷射加工係稱為銅直接加工法（Copper Direct)之習 知的方法。藉由該隆起部26a之稜線而形成之圓的直徑 D1，比銅箔13之開孔部28的直徑D2大。亦即始終是D1 >D2之關係。再者，藉由雷射光L1形成遮光膜24之開孔 部26的直徑D0比銅箔13之開孔部28的直徑D2大。亦 12 •201108903 即為D0>D2之關係，始終是d1>D〇>D2之關係成立。 其次，在絕緣層12中形成導通孔16。導通孔16之形 成亦藉由二氧化碳雷射光或YAG雷射等之雷射光L2進 行。此時之雷射光L2的光點徑D3比遮光膜24之隆起部 26a的稜線之直徑D1大（第1C圖）。亦即為D3>D1之關 係。藉此如第1D圖所示，藉由雷射光L2除去遮光膜24 之開孔部26周緣的隆起部26a之大部分，隆起部26a之高 度降低而概略平坦化，並且銅箔13之開孔部28的周緣部 28a露出於直徑D3擴張之開孔部27的内側。同時，藉由 銅鑛13之開孔部28遮蔽，而以其直徑D2之開孔形成導通 孔16 °此時’將雷射光L2之輸出調整為不貫穿背面侧之 銅镇14的程度。因此，雷射光^2之光點徑比UV雷射光 L1大’而光能密度亦即光之強度比UV雷射光L1小。 之後，在導通孔16内進行除膠渣處理，並如第2A圖 所示，將導電性膏18填充於導通孔16内。 其一入如第2B圖所示，剝離遮光膜24，將兩面銅箔板 22熱擠壓’使導電性膏Μ溶融、硬化’謀求銅箔13， 間之電性連接。其後，在形成電路配線13a，14a之表面與 背面的銅箔13，14上貼合餘刻抗蝕劑之乾膜3〇 (第 圖），曝光成指定之電路圖案並蝕刻，如第2D圖所示，形 成電路配線13a，14a。經過以上之製程，形成層間連接兩面 銅始板22之兩面的電路配線丨3a，14a之印刷電路板1〇。 採用該實施形態之印刷電路板10時，導電性膏18之 層間連接構件亦附著於位於導通孔16周緣之銅箔13的開 13 201108903 孔部28之周緣部28a，可確實形成電阻小之層間連接。此 1卜i採用該實施形態之印刷電路板1G的製造方法時，可以 單之程形成直彳！小之導通孔16 ’亦可確實將導電性膏 18填充於導通孔16内。此由於不妨礙藉由遮光膜24擴張 之^部27填充分散的金屬粒子之2次凝聚粒子，因此將 充分量之導電性膏18填充於導通孔16内。藉此，層間連 接/之電&連接確實，且強度亦高，對熱循環及熱衝擊等 電f·生連接的可#性提而，使用之電子機器的耐環境性能 及耐用性提高’且成本之增加亦少。 、此外，為了發揮本中請案發明之作用效果，必須為上 述之D3>D1的關係。例如第4圖所示，即使遮光膜24之 開孔邛26的直；^ D〇比鋼寫13之開孔部&直經d2大 (D0>D2)’雷射光L2之光點徑⑺比直徑大㈤〉 )若遮光膜24之隆起部26a的稜線之直徑D1比雷射 光L2之光點徑〇3小時（m>D3)，則不發揮上述之作用 效果。此因即使藉由雷射光L2之照射隆起部施仍殘留， ^電性嘗18無法與㈣13之開孔部28周圍充分接觸。 另外’本發明之印刷電路板與其製造方法並非限定於 上述實施形態者，可適宜選擇填充於導通狀導電性膏的 種類’亦可適宜設定堆疊於該印刷電路板上之電路板層 數。此外’亦可適宜設定絕緣層之厚度及材質，亦可適宜 設定雷射光之種類、照射直徑及照射方法。 [實施例1] 其次，就本發明之印刷電路板及其製造方法的一種實 201108903 施例說明於下。實施例i係在兩面㈣聚醯亞胺基板之〜 面貼合PET—製之遮光膜。而後，從遮光膜側之面使用uv 雷射光，並藉由鋼直接加工法，在遮光膜及銅箔上形成開 孔部。此時開孔部之環狀棱線的直徑D1 為 Dl=97 # m。該 直仕D1之值係彳足形成於兩面銅箔板之4萬個開孔部選擇$ 個開孔部而求取平均值之值。此外，形成於銅之開孔部 的直徑D2為1)2=50#!^ 其次，藉由YAG雷射在聚醯亞胺基板上形成導通孔。 此時之雷射光的光點徑，以包圍遮光膜開孔部之棱線的方 式’為比稜線之直徑D1大的直徑D3，且係D3=l〇〇^m 之光點徑。在聚醯亞胺基板上形成導通孔後，進行除膠浩 處理，填充導電性貧並使其乾燥，再剝離遮光膜，進行熱 擠壓。而後，籍由熱擠壓使導電性膏硬化，並且將導電性 膏壓縮於導通孔内，其後進行銅箔之圖案化。實施例1為 了測定電阻值’而進行串級鏈(Daisy Chain)之圖案化。 [比較例1] 此外，比較例1係藉由UV雷射光，在遮光膜上形成 開孔部之棱線的直徑為97 // m之開孔部，亦在銅箱上形成 開孔部。此時形成於銅箔之開孔部的直徑D2亦為D2==5〇 //m。之後’在遮光膜之開孔部内’以光點徑為6〇# m之 雷射光’在聚醯亞胺基板上形成導通孔。之後，經過與上 述同樣之製程，進行遮光膜之剝離、導電性膏之填充及圖 案化等。 結果’實施例1之母1個導通孔的平均電阻值為 15 201108903 Ω而比較例1則為8.1 ιηΩ。此外，關於4萬個導通孔之 電阻值的偏差（分散cr )，實施例1為σ =1.2 ιηΩ，而比 較例1則為σ =2.4 ιηΩ。此外’實施例1之印刷電路板即 使在熱循Κ驗中仍不致發生問題。 口此’確認本申請案發明之實施例1的電阻值低，且 電阻值之偏差亦小。 【圖式簡單說明】 第1Α圖係顯示本發明一種實施形態之印刷電路板的 製程之概略剖面圖（之一）。 第1Β圖传為 ., ⑦顯示本發明一種實施形態之印刷電路板的 製程之概略剖面圖（之二)。 第1C圖位s ^ q诉顯示本發明一種實施形態之印刷電路板的 、主之戈略剖 第山圖 制 糸_示本發明一種實施形態之印刷電路板的 ::略'面圖(之四)。 ^ ^^圖係顯示本發明一種實施形態之印刷電路板的 弟1圖之製海 第2b 的後續製程之概略剖面圖（之一）° Μ 1 ® β β圖係顯示本發明一種實施形態之印刷電路板的 弟1圖之製程 第2c W谈續製程之概略剖面圖（之二）° 第1圖之製^^係颟示本發明一種實施形態之印刷電路板的 第^的後續製程之概略剖面圖（之三）。 第1圖之製示本發明—種實施形態之印別電路板的 °的後續製程之概略剖面圖（之四）。 201108903 第3A圖係顯示先前之印刷電路板的製程之概略剖面 圖（之一）。 第3B圖係顯示先前之印刷電路板的製程之概略剖面 圖（之二）。 第3C圖係顯示先前之印刷電路板的製程之概略剖面 圖（之三）。 第3D圖係顯示先前之印刷電路板的製程之概略剖面 圖（之四）。 第3E圖係顯示先前之印刷電路板的製程之概略剖面 圖（之五）。 第4圖係顯示本發明之比較例的印刷電路板之製造方 法的概略剖面圖。 主要元件符號說明】 1 絕緣層 2,3 銅羯 4 兩面銅箔板 5 遮光膜 6 導通孔 8 導電性膏 10 印刷電路板 12 絕緣層 13, 14 銅羯 13a, 14a 電路配線 17 201108903 16 導通孔 18 導電性膏 22 兩面銅箔板 24 遮光膜 26 開孔部 26a 隆起部 27 開孔部 28 開孔部 28a 周緣部 30 乾膜 D0，D1，D2，D3 直徑 LI UV雷射光 L2 雷射光The metal collar of the surface is formed on the end surface of the metal case which is formed to have a concave surface penetrating through the earth plate table U so as to fill the conductive edge. In addition, the interlayer contact hole disclosed in Patent Document 3 is filled with two-sided printing of a conductive paste for interlayer conduction: 2.201108903 One side of a copper foil forming a circuit, and a light shielding film is attached as a printing Use a mask. Then, when the via hole is formed, first, an opening portion having a larger aperture than the via hole is formed in the light shielding film by laser irradiation. Next, a via hole having a diameter smaller than that of the opening portion is formed in the opening portion by the laser light. At this time, a through hole is formed in the insulating layer together with the copper foil on the surface, and the copper foil on the back surface is exposed in the via hole. Thereafter, a conductive paste is filled in the via hole, and the insulating enamel is peeled off, and the filled conductive paste is thermally pressed and cured. Further, a resist is applied onto the copper foil on the surface, the specified circuit pattern is exposed, and the resist other than the circuit pattern is removed by etching to form a method of manufacturing the printed circuit board on both sides of the circuit. The system first forms a large opening in the light shielding film, and forms a small diameter via hole on the inner side thereof to increase the contact area between the copper foil forming the circuit and the conductive paste in the via hole. In the method of the first method, the peripheral portion of the opening portion of the light-shielding film formed by the laser light is raised, and the aperture of the light-shielding film is smaller than the conduction aperture, thereby hindering the filling of the conductive paste. When the opening of the light-shielding film is narrow, the secondary aggregated particles which block the metal particles dispersed in the conductive paste intrude into the conductive paste from the opening portion during the filling process. Further, it is also possible to form a paste deposit or the like around the raised portion of the opening portion to prevent the filling into the opening portion. Further, the interlayer connection structure disclosed in Patent Document 1 has a process of attaching the conductive paste to the through hole and then attaching the alloy (4). Therefore, the process is complicated, and when the metal foil is used to form the terminal face of the circuit, it is difficult to form a layer. The position of the conductive paste connected to the gate is correct, and thus (4) is not used for the circuit board of the fine electric pattern. Further, in the interlayer connection method disclosed in Patent Document 2, it is difficult to form a concave portion on the end surface of the metal foil on the surface, and it is not applicable to the thin metal foil and the fine circuit pattern of 201108903'. Furthermore, the interlayer connection method disclosed in Patent Document 3 is formed by forming a hole in the light shielding film by laser light, and forming a hole having a smaller aperture than the aperture by the laser light, and further forming A through hole is formed in the insulating layer by laser light. After that, the conductive paste is filled and electrically connected to the metal foil on the front surface and the back surface, and the manufacturing process is complicated, and the opening of the laser is inhibited from affecting the original opening formed in the light shielding film, and the opening is large. Suitable for fine circuit patterns. <Prior Art Document><PatentDocument> [Patent Document 1] Japanese Patent No. 2874581 [Patent Document 2] Japanese Laid-Open Patent Publication No. 2003-188533 [Patent Document 3] 曰本特开2007-281336 SUMMARY OF THE INVENTION [Problems to be Solved by the Invention] An object of the present invention is to solve the above problems and achieve the following objects. That is, it is an object of the present invention to provide a printed circuit board which is sure to carry out interlayer connection of a conductive paste, has low electrical resistance and high connection reliability, and a method of manufacturing the same. (Means for Solving the Problem) The means for solving the above problems are as follows. That is, <1> a method of manufacturing a printed circuit board having: an insulating layer; a circuit wiring formed on both sides of the insulating layer, 6 201108903 and composed of a metal foil; and a conductive paste And electrically connected to each of the circuit wirings formed on both sides of the insulating layer, and is characterized in that a surface of the circuit wiring on one side of the insulating layer is bonded to the light shielding film. The first laser beam is irradiated onto the surface of the light shielding film, and the opening portion is formed on the circuit wiring on one side of the light shielding film and the insulating layer, and is formed in the light shielding film by a light spot diameter ratio. The second laser beam having a large ridge line of the peripheral portion of the hole portion has a via hole formed in the insulating layer, and the conductive paste is filled in the via hole to electrically connect the circuit wiring. <2> The method of manufacturing a printed circuit board according to the above aspect, wherein the second laser light has a larger spot diameter than the first laser light, and the light energy density is smaller than the first laser light. <3> The method of manufacturing a printed circuit board according to the above <1> or <2>, wherein the diameter of the opening portion formed by the first laser light on the light shielding film is larger than the circuit wiring on one side of the insulating layer The diameter of the hole portion is large. The method of manufacturing a printed circuit board according to any one of the above-mentioned <1>, wherein the via hole is one side of the insulating layer having the opening portion formed by the first laser light. The circuit wiring is formed as a mask by the second laser light penetrating through the insulating layer. <5> The method of manufacturing a printed circuit board according to the above aspect, wherein the via hole is formed by the second laser light, the dross is removed, the conductive paste is filled in the via hole, and drying and hot pressing are performed. And electrically connected to each circuit wiring. <6> - A printed circuit board having: an insulating layer; a circuit wiring, [201108903] formed on both sides of the insulating layer and composed of a metal foil; and a conductive paste filled in the insulating layer Each of the circuit wirings formed on both surfaces of the insulating layer is electrically connected to each other, and is characterized in that the surface of the circuit wiring on one side of the insulating layer is bonded to the surface of the circuit wiring by the first light. The opening portion of the circuit wiring on one side of the insulating layer is formed by laser light, and the diameter of the ridge line formed on the peripheral edge of the opening portion of the light shielding film is larger by the spot diameter than the first laser light. The second laser beam is irradiated onto the opening portion of the circuit wiring on one side of the insulating layer to form the via hole, and the conductive paste is stacked on the peripheral portion of the via hole formed by the second laser light. The aforementioned circuit wiring surface of the inner portion of the film opening portion. <7> The printed circuit board according to the above <6>, wherein the insulating layer is a polyimide and has a double-sided copper foil plate in which copper II is bonded to both surfaces of the insulating layer. (Effect of the Invention) When the printed circuit board of the present invention and the method of manufacturing the same are used, it is possible to surely fill the conductive paste with the bonding area of the conductive paste and the metal foil forming the circuit in the through hole of each layer of the circuit to which the printed circuit board is connected. And the joint strength is improved. Thereby, the electrical resistance of the interlayer connection of the conductive paste is low, the reliability of the connection is high, and the reliability of electrical connection such as thermal cycle and thermal shock is also improved. As a result, the environmental resistance and durability of the electronic machine are improved, and the cost is increased. [Embodiment] (Manufacturing method of printed circuit board) 201108903 The method for manufacturing a printed circuit board according to the present invention includes at least a light-shielding film bonding process, an opening forming process, a via forming process, and a conductive paste filling process, and further Contains other processes that are suitable for your needs. <Light-shielding film bonding process> The light-shielding film bonding process is a process in which a light-shielding film is bonded to the surface of the circuit wiring on one side of the insulating layer. A light-shielding film The light-shielding film is not particularly limited and may be appropriately selected depending on the purpose, for example, a method of applying a binder to a PET film. The method of laminating the above-mentioned light-shielding film is not particularly limited, and may be appropriately selected depending on the purpose, and is, for example, a vacuum lamination method or the like. Further, since the light-shielding film is directly bonded to the copper foil on which the circuit is not formed, the surface is uniform, and there is no unevenness or step difference, and the film can be easily and favorably bonded. Insulating layer 1 The material of the insulating layer is not particularly limited as long as it has insulating properties, and may be appropriately selected depending on the purpose. However, for example, polyimine is preferred. • The thickness of the above insulating layer is not particularly limited and may be appropriately selected depending on the purpose. A circuit wiring 1 The circuit wiring is not particularly limited and may be appropriately selected depending on the purpose, and is, for example, a metal foil, of which copper foil is preferred. <Opening Portion Forming Process> The opening forming process is performed by irradiating the first [s 9 201108903 laser light on the surface to which the light shielding film is bonded, and in the circuit wiring on one side of the light shielding film and the insulating layer An opening portion is formed. —1st laser light The first laser light is not particularly limited and may be appropriately selected depending on the purpose. However, for example, it is preferably a UV laser light such as an excimer laser. <Bounding Hole Formation Process> The via hole forming process is formed in the insulating layer by a second laser light having a diameter smaller than a diameter of a ridge line formed in a peripheral edge of the opening portion of the light shielding film. The process of the aforementioned via holes. A second laser light The second laser light is not particularly limited and may be appropriately selected depending on the purpose, such as carbon dioxide (C02) laser light or YAG laser. Further, the light energy density of the second laser is preferably smaller than that of the first laser. A ridge line-protrusion portion formed in the peripheral ridge portion of the opening portion is formed in a ring shape which is bulged at a peripheral portion of the opening portion of the light shielding film. The ridge line of the aforementioned ridge portion is a line connecting the apexes of the ridge portion. The method for measuring the diameter of the ridge line is not particularly limited, and may be appropriately selected depending on the purpose, and is, for example, a cross-sectional observation using a microscope or a measurement method for surface observation. <Electrical paste filling process> The conductive paste filling process is a process in which a conductive paste is filled in a via hole and electrically connected to each circuit wiring. A conductive paste: the conductive paste is not particularly limited as long as it is a metal powder of a high melting point gold. 201108903 genus and a low melting point metal, and is alloyed by a subsequent heat treatment. Suitable for the purpose. The high-melting-point metal is not particularly limited and may be appropriately selected according to the purpose, and is, for example, a particle containing at least copper (a particle of a copper monomer or an alloy particle containing one or more metals of gold, silver, zinc, and nickel and copper). )Wait. Further, the surface of the metal particles may be coated with gold, silver, zinc or nickel or an alloy thereof by plating or the like. The average particle diameter of the metal particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably from about 1 / m to about 10 / / m (e.g., 6 / / m). The low melting point metal is not particularly limited and may be appropriately selected depending on the purpose, and is, for example, a tin or a tin-containing alloy (e.g., solder) particles. The solder is not particularly limited and may be appropriately selected according to the purpose, for example, tin-copper solder, tin-silver solder, tin-silver-copper solder, or any one or more of marriage, rhyme, and silk. And further suitable for the mixer and so on. The resin for the adhesive of the conductive paste is not particularly limited as long as it is a thermoplastic resin, and can be appropriately selected according to the purpose, and is, for example, a polyether, a polyolefin, a polyamide, a polyimide, or a poly Resins such as ether imine, polyphenylene ether, polyphenyl sulfide, and polyglycolal butyrene, and others are epoxy resins, acrylic resins, and the like. Method of Filling the Conductive Paste The method of filling the conductive paste is not particularly limited, and may be appropriately selected depending on the purpose, but may be, for example, a method such as screen printing or jet printing. Further, a method in which a peelable film is used as a mask material and is filled in a via hole by [s 11 201108903 extrusion can also be used. Hereinafter, an embodiment of a printed circuit board of the present invention will be described with reference to Figs. 1 and 2 . In the printed circuit board 10 of this embodiment, the circuit wirings 13a and 14a formed of the metal foil copper foils 13, 14 are formed on both surfaces of the insulating layer 12. The insulating layer 12 is made of an insulating substrate such as polyimide, and the copper foils 13 and 14 are bonded to both surfaces. The copper foils 13, 14 on the surface of the insulating layer 12 and the back surface form a predetermined circuit pattern through a process to be described later, thereby constituting the circuit wirings 13a, 14a. The insulating layer 12 is formed with a via hole 16 for electrically connecting the surface and the back surface of the circuit wirings 13a, 14a, and the surface wirings 13a, 14a of the front and back surfaces are connected by the interlayer connection member of the conductive paste 18. Next, a method of manufacturing the printed circuit board 10 of this embodiment will be described based on Figs. 1 and 2 . First, as shown in Fig. 1A, the light-shielding film 24 is bonded to the side surface of the copper foil 13 on which the polyimide foil or the like is used as the substrate. Next, on the double-sided copper foil plate 22, UV laser light L1 such as a pseudo-molecular laser is irradiated from the side of the light-shielding film 24, and an opening 26 is formed in the light-shielding film 24, and at the same time, an opening portion is formed in the copper foil 13. 28 (Fig. 1B). At this time, a bulging annular portion 26a is formed in the peripheral portion of the opening portion 26 of the light shielding film 24. This laser processing is known as the method of copper direct processing (Copper Direct). The diameter D1 of the circle formed by the ridge line of the ridge portion 26a is larger than the diameter D2 of the opening portion 28 of the copper foil 13. That is, it is always the relationship of D1 > D2. Further, the diameter D0 of the opening portion 26 in which the light shielding film 24 is formed by the laser light L1 is larger than the diameter D2 of the opening portion 28 of the copper foil 13. Also 12 • 201108903 is the relationship of D0>D2, always the relationship of d1>D〇>D2 is established. Next, via holes 16 are formed in the insulating layer 12. The formation of the via hole 16 is also performed by laser light L2 such as carbon dioxide laser light or YAG laser. At this time, the spot diameter D3 of the laser light L2 is larger than the diameter D1 of the ridgeline of the raised portion 26a of the light shielding film 24 (Fig. 1C). This is the relationship between D3 > D1. As a result, as shown in FIG. 1D, most of the raised portion 26a of the peripheral edge of the opening portion 26 of the light-shielding film 24 is removed by the laser light L2, and the height of the raised portion 26a is lowered to be substantially flattened, and the opening of the copper foil 13 is opened. The peripheral edge portion 28a of the portion 28 is exposed inside the opening portion 27 in which the diameter D3 is expanded. At the same time, the opening of the copper ore 13 is shielded, and the opening 16 is formed by the opening of the diameter D2. At this time, the output of the laser light L2 is adjusted so as not to penetrate the copper town 14 on the back side. Therefore, the spot diameter of the laser light ^2 is larger than that of the UV laser light L1, and the light energy density, that is, the intensity of light is smaller than that of the UV laser light L1. Thereafter, the desmear treatment is performed in the via hole 16, and as shown in Fig. 2A, the conductive paste 18 is filled in the via hole 16. As shown in Fig. 2B, the light-shielding film 24 is peeled off, and the double-sided copper foil sheet 22 is thermally pressed to melt and harden the conductive paste, and the copper foil 13 is electrically connected. Thereafter, a dry film 3 余 (pictured) of the resist is bonded to the copper foils 13 and 14 on the surface and the back surface of the circuit wirings 13a and 14a, and exposed to a predetermined circuit pattern and etched, for example, 2D. As shown in the figure, circuit wirings 13a, 14a are formed. Through the above process, the printed circuit board 1A of the circuit wirings 3a, 14a connecting the two sides of the copper starting plates 22 on both sides is formed. When the printed circuit board 10 of this embodiment is used, the interlayer connection member of the conductive paste 18 is also adhered to the peripheral portion 28a of the opening portion 13 201108903 of the copper foil 13 located at the periphery of the via hole 16 to form a layer having a small electric resistance. connection. When the manufacturing method of the printed circuit board 1G of this embodiment is used, it is possible to form a straight line in a single process! The small via hole 16' can also surely fill the conductive paste 18 in the via hole 16. Since the second-stage aggregated particles of the dispersed metal particles are not impaired by the portion 27 expanded by the light-shielding film 24, a sufficient amount of the conductive paste 18 is filled in the via holes 16. Thereby, the interlayer connection/electrical connection and the connection are reliable, and the strength is also high, and the environmental resistance and durability of the electronic device used are improved for the electrical and thermal shock and the like. And the increase in cost is also small. In addition, in order to exert the effect of the invention of the present invention, it is necessary to have the relationship of D3 > D1 described above. For example, as shown in Fig. 4, even if the opening 邛 26 of the light-shielding film 24 is straight; ^ D 〇 is larger than the opening portion of the steel writing 13 & straight through d2 (D0> D2) 'light spot diameter of the laser light L2 (7) When the diameter D1 of the ridge line of the raised portion 26a of the light-shielding film 24 is smaller than the light spot diameter of the laser light L2 by 3 hours (m > D3), the above-described effects are not exhibited. This is because even if the ridge portion is left by the irradiation of the laser light L2, the electric taste 18 cannot be sufficiently brought into contact with the periphery of the opening portion 28 of the (four) 13. Further, the printed circuit board and the method of manufacturing the same according to the present invention are not limited to the above-described embodiments, and the type of the conductive paste to be filled can be appropriately selected. The number of circuit boards stacked on the printed circuit board can be appropriately set. In addition, the thickness and material of the insulating layer may be appropriately set, and the type of the laser light, the irradiation diameter, and the irradiation method may be appropriately set. [Embodiment 1] Next, a practical example of a printed circuit board of the present invention and a method of manufacturing the same will be described below. In the example i, a light-shielding film made of PET was laminated on the surface of the double-sided (tetra) polyimide substrate. Then, uv laser light is used from the side of the light-shielding film, and an opening portion is formed on the light-shielding film and the copper foil by direct steel processing. At this time, the diameter D1 of the annular ridge line of the opening portion is D1 = 97 # m. The value of the direct D1 is obtained by selecting the opening portions of the 40,000 opening portions of the double-sided copper foil sheet to obtain an average value. Further, the diameter D2 formed in the opening portion of the copper is 1) 2 = 50 #! ^ Next, a via hole is formed on the polyimide substrate by the YAG laser. The spot diameter of the laser light at this time is a diameter D3 larger than the diameter D1 of the ridge line by the ridge line surrounding the opening portion of the light-shielding film, and is a spot diameter of D3 = l〇〇^m. After a via hole is formed on the polyimide substrate, the gel removal treatment is performed, the filling is poor, and the film is dried, and the light shielding film is peeled off to perform hot extrusion. Then, the conductive paste is cured by hot extrusion, and the conductive paste is compressed in the via hole, and then the copper foil is patterned. In the first embodiment, the resistance value was measured and the pattern of the Daisy Chain was patterned. [Comparative Example 1] Further, in Comparative Example 1, an opening portion having a diameter of 97 / m in the ridge line of the opening portion was formed on the light-shielding film by UV laser light, and an opening portion was formed in the copper box. The diameter D2 formed at the opening portion of the copper foil at this time is also D2 == 5 〇 //m. Then, in the opening portion of the light-shielding film, a via hole was formed on the polyimide substrate with a laser light having a spot diameter of 6 〇 #m. Thereafter, the same process as described above is carried out to remove the light-shielding film, fill and pattern the conductive paste, and the like. As a result, the average resistance value of one of the via holes of the mother of Example 1 was 15 201108903 Ω, and that of Comparative Example 1 was 8.1 ηηΩ. Further, regarding the deviation (dispersion cr) of the resistance values of 40,000 via holes, Example 1 was σ = 1.2 ηηΩ, and Comparative Example 1 was σ = 2.4 ηηΩ. Further, the printed circuit board of the embodiment 1 does not cause problems even in the heat cycle test. It is confirmed that the electric resistance value of the first embodiment of the invention of the present application is low, and the variation in the electric resistance value is small. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view (1) showing a process of a printed circuit board according to an embodiment of the present invention. Fig. 1 is a diagram showing a schematic sectional view (part 2) of a process of a printed circuit board according to an embodiment of the present invention. FIG. 1C is a schematic view of a printed circuit board according to an embodiment of the present invention, showing a printed circuit board according to an embodiment of the present invention. four). ^^^ 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图The schematic diagram of the process of the second embodiment of the printed circuit board is shown in the second section. The second embodiment of the circuit board of the first embodiment shows the subsequent process of the printed circuit board according to an embodiment of the present invention. A schematic cross-sectional view (3). BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view (fourth) of a subsequent process of the printing circuit board of the present invention. 201108903 Figure 3A shows a schematic cross-sectional view of one of the previous printed circuit boards (one). Fig. 3B is a schematic cross-sectional view (Part 2) showing the process of the prior printed circuit board. Fig. 3C is a schematic cross-sectional view showing the process of the prior printed circuit board (3). Fig. 3D is a schematic cross-sectional view (fourth) showing the process of the prior printed circuit board. Fig. 3E is a schematic cross-sectional view (fifth) showing the process of the prior printed circuit board. Fig. 4 is a schematic cross-sectional view showing a method of manufacturing a printed circuit board of a comparative example of the present invention. Explanation of main component symbols] 1 Insulation layer 2,3 Copper crucible 4 Double-sided copper foil plate 5 Light-shielding film 6 Via hole 8 Conductive paste 10 Printed circuit board 12 Insulation layer 13, 14 Beads 13a, 14a Circuit wiring 17 201108903 16 Via hole 18 Conductive paste 22 Double-sided copper foil plate 24 Light-shielding film 26 Opening portion 26a Uplift portion 27 Opening portion 28 Opening portion 28a Peripheral portion 30 Dry film D0, D1, D2, D3 Diameter LI UV laser light L2 Laser light