TW517360B - Enhanced type wafer level package structure and its manufacture method - Google Patents
Enhanced type wafer level package structure and its manufacture method Download PDFInfo
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- TW517360B TW517360B TW090131458A TW90131458A TW517360B TW 517360 B TW517360 B TW 517360B TW 090131458 A TW090131458 A TW 090131458A TW 90131458 A TW90131458 A TW 90131458A TW 517360 B TW517360 B TW 517360B
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Description
517360 五、發明說明(1) 【發明之應用領域】 本發明係關於一種晶圓級構裝的結構及其製造方法, 且特別是關於一種增益型晶圓級構裝之結構及其製造方 法。 【發明背景】 近年來’晶圓級的晶片尺度構裝(wafer level chip scale packages,wafer level CSP)或稱為晶圓級構裝 (wafer level package)已被當成一種低成本的半導體元 件封裝技術,其廣泛地應用於製作高容量的積體電路晶 片。其中一種為csp(晶片尺度構裝)製程,其由丁essera Company所提出’他們亦稱此技術為微面陣列焊料球 (micro Ball Grid Array ’micro-BGA)封裝方法,此種 mi cro-BGA封裝方法被應用於同時封裝具有多個緊密規則 排列於電路板或基板上方的待封裝物,同時此種 mlCr〇 —BGA封裝方法是一種高密度的封裝方法,且其結合 I覆晶裝配與表面黏著封裝的優點,因此利用此晶圓《及口構 裝技術可以同時封裝整個晶片,而不需像傳統覆晶封 形成焊料球以進行特殊的接合製程,另外晶片尺寸構裝= 傳統的四面平方(Quad flat)構裝技術可以提供較多數"旦 的輸入/輸出接點。 里 CSP製私的晶圓級構裝與其它構裝技術不同之處在於 ^ 中間介層(interposed layer),此一中間介声是 由具柔軟性、可撓性的材料製成,此中間介層不僅可以= 收在封裝步驟中所產生的機械應力,更可允許在晶粒與基
第4頁 517360 五、發明說明(2) 板接合時因熱膨脹係數不同所產生的熱膨服, 層在此所擔任的角色是應力緩衝層及熱膨服 = 晶圓級構裝尚具有其它特色,亦即與micr〇_BGA封曰裝’另外 同’能夠使用表面黏著技術(surfaee mQunt technology,SMT)製程與電路板進行裝 在典型的㈣o-BGA封裝巾,是/由一柔乍軟性的中門 介層(可能包含有電路)以連接位於積體電路晶間 與位於軟性電路(nexible Clrcuit)之焊料凸 $墊 其中軟性電路的厚度大約在25 左右,係由—高八’ 料如聚亞醯胺(P〇ly imide)所製成。中間介層為厚二 BO/Zm之石夕膠彈性體(SlHc〇ne eiast〇〇]er) ’此_二夕、為 性體層可以提供在三軸方向的柔軟性及可撓性以減輕/制 造過程中所產生的應力及因晶粒與基板配合失二衣 熱膨脹。 田1座生的 、不過’上述之中間介層(如矽膠彈性體層)由_ 式杈數之彈性材料製成,因為當楊式模數太高時,车楊 材料的性質比較硬,當此晶圓級晶片尺寸構裝承 ^ ^ 脹 A 數(coefficient of thermal expansion,以下:\/ CTE)不匹配所引發之應力時,將因揚式係數過高而a間 緩衝層之效果出現,而造成可靠度上的顧慮。所以恶應力σ 性材料層的的材料選擇(CTE值的選擇)成為CSp 此無 重點。 衣技術的 此外,在結構上,中間介層的邊緣,其構造上—π、 垂直的結構,此種結構會在銳角處形成一應力集中點I為 *、、、 it 匕
517360 五、發明說明(3) _— 點的金屬覆蓋層,更可能因為CTE值的差距過大而造成灣 蓋於其上的金屬線龜裂的現象。 仅 為了防止可能龜裂的現象,一種做法是將邊緣的垂直 結構改為一頃斜的斜坡結構,如此即可防止此種問題。不 過,由於適當的中間介層材料上的問題,所以,此種 值差異過大的問題,仍未獲得解決。 在現有的CSP製程上,如Tessera之micro-BGA、 ShellCase 之ShellPack、Sandia 之mini-BGA 等製程均相者 繁瑣’此將造成製作成本無法有效降低,更甚者會因势程 控制不好而影響產品之可靠性。此外,大部份現有的構裝 設計尚無法滿足南頻元件,如r a m b u s記憶體之電性需東。 對於這些問題,習知技術以有解決方案,如專利申嗜 案苐8 8 1 2 0 3 4 0案號所述,其解決方法為運用兩層彈性材料 層作為如上述之中間介層。如第「1 A與1 B」圖所示,此種 晶圓級構裝構造’其包含有:一具有多個積體電路晶粒1 〇 的矽晶圓基板1 2,每一晶粒1 〇具有至少一第一丨/ 〇焊塾 1 4 ;多個導電金屬柱1 8,各別形成於每一晶粒1 〇的第一 I/O焊墊14上以形成導通;一第一彈性層20,形成於石夕晶 圓基板的介電層16上,使導電金屬柱18之頂面能露出;一 第二彈性層2 2,形成於未有導電金屬柱1 8的部份第一彈性 層20上;多個金屬線24,各具有一第一末端與導電金屬柱 18形成導通,及自第一末端延伸出形成於第二彈性層22上 的一第二末端;一保護層2 6,形成於金屬線24表面;多個 曝路出表面的弟>一 I / 〇焊塾2 8 ’分別形成於金屬線之第二
517360 五、發明說明(4) 末端以形成導通;以及多個焊料球3 2,分別形成於第二 I/O ¥ 墊 28 上的 UBM 層(Under Bump Metallurgy,覆晶球下 金屬層)3 0以形成導通。 第「1 A與1 B」圖的差別在於第二彈性層2 2的圖案設計 不同,第1A圖為分離式圓丘圖案,第1B圖則為連續式圓丘 圖案。此種晶圓級構裝的兩層彈性層構造解決了 csp製程 中’中間介層材料選擇上的困難,直接以兩層熱膨脹係數 不同的彈性層解決了結構上的應力問題。 不過’此種構造在導電金屬柱丨8與第一彈性層2 〇之間 的接合面間形成一尖銳的接合處35。由於導電金屬柱18與 第一彈性層2 0的CTE值不同,因此,在此接合處3 5易造成 因製紅過私中的鬲熱與降溫過程中因兩者的CTE質不同而 產生的龜裂現象。 【發明之目的與概述】 有鑑於此,本發明的日沾A # μ Θ的目的在楗供一種增益型晶圓級構 裝之結構及其製造方法,可改盖羽+ U莊 丄 ^ A J ^善白Ί知封裝方式的缺點及不 佳之處。 為達上L目的,本發明提供一種^ ^ ^ ^
結構,同樣提供兩層彈性声作Α胨;/ 土日日圓、反稱衣 一呈右夕并卿午/ 為應力緩衝層,至少包括 …有夕们積肢电路晶粒的矽晶圓 曰 少一第一I/O焊墊;多個全屬覆罢敗母日日粒具有
料的筮τ /n t日鈦L 。萄设现層,各別形成於每一曰E 粒的弟一 I /0 干墊上以形成導 — 石々曰圓其柘卜,你人π西+ 弟一弹性層,形成方 矽曰曰η基板上 <吏金屬覆蓋層之頂面能霖出 層,形成於未有金屬覆蓋層的部 一 I切弟一弹性層上;多個
517360 五、發明說明(5) 屬線,各具有一第一末端與金屬覆蓋層形成導通,及自第 -末端延伸出形成於第二彈性層上的—第二末^;一保護 層’形成於金屬線表面以形成保護;多個曝露出表面的第 二"。❹,分別形成於金屬線之第二末端以形成導通; 以及多個焊料球,分別形成於第-丨/ 通。 乐一1/0焊墊上以形成導 此種構造主要針對以銅為材料的 炎u丨,…μ制 ~可杆的銅線製程,對於以鋁 為材料的鋁線“呈’則可免除金屬覆蓋層。此外,本發明 的金屬覆蓋層,由於其厚度甚薄,所以 可以 較專利申請案第8812〇34〇案號之第—彈性層薄,因:,也 =前:述;尖銳角的應力問題;在沒有金屬覆蓋層的 、=,弟2性層可以更薄’可達到依設計需求設計不 同的厚度之目的。特別的是,本發明所 彈性層與第二彈性層的邊緣設計Λ俩处沾/、 、、口構弟 又°Τ马傾斜結構,因此,沒有 直角式的設計會產生較高應力的問題。 此外’為達上述目的’-方τίή舍j Υ α/ . 万面製程上均是使用現有凸 Τ成型(b_ng)的設備即可完<,可減低設備投資成 本,另一方面也使製程的步驟更加簡化。 。根據上=本毛明之目的,本發明更提供一種增益型晶 圓級構裝的製作方法’其步驟包含有:提供一石夕晶圓基 板’其表面形成有多個積體電路晶 少一個第一 I /0焊墊;形成一全屬舜掌昆 曰寸上/、有至 至屬覆盍層於第一 I/O焊塾霖 *的表面;形成一具足夠彈性之第板 上,並使金屬覆蓋層之頂面露出.拟士、曰7曰日W基板 。出,形成一具足夠彈性之第 517360 五、發明說明(6) 二彈性層於未有金屬覆蓋層的部份第— 一金屬線,具有—第一末端與金屬覆蓋岸曰二形成至少 及自第一末端延伸出形成於第二彈性層上=一二軋連接, 沈積一保護層於金屬線表面;金屬線‘第 ' :弟二末端; 一第二1/0谭塾,並使第二I/O谭塾裸露末端定義形成 焊料球於第二1/0焊墊。此種製程主要針;’以及形成— 銅線製程’對於以鋁為材料的鋁線制要對以銅為材料的 金屬覆蓋層之步驟。 衣^,則可免除形成該 為讓本發明之上述和其他目的、 顯易懂,下文特舉一較佳實施例,、=、和優點能更明 細說明如下: 亚配合所附圖式,作詳 【發明之詳細說明】 罝亡^發明更揭露一種增益型晶圓級構f之处播 一有多個金屬線以將I/O焊墊由積 、之、、、口構,此結構 至晶粒的令央,這些金屬線係形成於电一路阳粒之四周延伸 層之上,此應力緩衝層係由彈性材 :g式的應力緩衝 路晶粒之頂部’而金屬線經由焊墊鱼二,且=積於積體電 用)而從積體電路晶片連接至外面雷、孟萄覆盍層(或者不 電路板係經由焊墊及以面矩陣排歹二反’其中連接外面 請參考第「2A與2B」圖,本於干二球。 之結構’其包括:一具有多個積型晶圓級構裝 板42,每一晶粒40上都有至少一二路曰曰粒4〇的矽晶圓基 金屬覆蓋層48,各別形成在第一1/〇弟—j/〇焊墊44 ;多個 通;第-彈性層50 ’形成在矽晶干44上以形成導 u丞板42上,使金屬覆蓋
II $ 9頁 517360 五、發明說明(7) 層48之頂面露出,第二彈性層52 ’形成在未有金屬覆蓋層 48的部份第一彈性層50上’·多個金屬線54,各具有一第一 末端與金屬覆蓋層48形成導通,及自第一末端延伸出形成 於第二彈性層52上的一第二末端;保護層56,覆蓋於金屬 線54表面以形成保護;多個曝露出表面的第二1/〇焊墊 5 8,分別形成於金屬線之第二末端以形成導通;以及多個 焊料球6 2,分別形成於第二I / 0焊墊上以形成導通。 此種構造主要針對以銅為材料的銅線製程,亦即,金 屬覆蓋層係用於保作為銅導線的緩衝與保護。若對於以銘 為材料的鋁線製程,則可免除金屬覆蓋層4 8,同樣地,在 · 製程上可以減少多個步驟。 其中,第一及第二彈性層50、52為一揚式模數 (Young’ s module)為小於6MPa的彈性材料層,亦即,可自 Dow Corning HIPEC Ql-4939 -Dow Corning HIPEC SDA 6501或Shin Etsu KJR9050E等材料任選一種。如此選擇乃 因為當楊式模數太高時,代表此材料的性質比較硬,當此 晶圓級晶片尺寸構裝承受因熱膨脹係數(c〇eff icient thermal expansion ’CTE)不匹配所引發之應力時,將因 揚式係數過高而無應力緩衝層之效果出現,而造成可靠度 · 上的顧慮。 所以’第一彈性層5〇可選CT]E值較低者,而第二彈性 層5 2則可選CTE值較高者,以作較恰當的應力緩衝。另 外’第一彈性層5 〇形成的厚度可在4〜2 〇 β ^之間,第二彈 性層52形成的厚度則可在4〜1〇〇 之間。
517360 五、發明說明(8) 形成兩層彈性層也可提供較高的隔離(standoff), ΐ f裝的可靠性增加,另一方面也能符合高頻元件所需之 ==特性,使製得的構裝結構能適用於例如 寺高頻元件封裝之用。 ^第一及第二1/0焊墊44、58的材料可選自銅、鋁、鋁 口金或銅合金材質的中任一者;此外,在該第二I / 〇焊墊 δ上還有一層UBM層60,以與焊料球62相連接。 ς9值得注意的是,如第2A圖所示,本發明的第二彈性層 n If :圓丘狀的圖案;或者是形成分離成島狀的複數個 ^ : 如第2β圖所示;或者,彳用兩種圖案任意搭 配。運用何種圖t,可視1/〇焊墊的數量以及需求作一調 根f上述所揭露之方法,現配合「第3A〜3D圖」所示 穿:制:::驟的剖面圖來加以說明整個增益型晶圓級構 衣的製造方法,如下所述: 姓谨首f ^ I考第3 A圖’其顯不本發明所揭露之晶粒4 0的 結構,如圖所示。 首^,先於石夕晶圓基板42之頂面形成第一1/〇焊墊 以使ΐ 一 τ頂:上積一具絕緣性的介電層46(也可為絕緣層) 使弟1/0 *干墊44埋入於此介電層46中,而第一 4二由rt屬:銘或銅製成。接著,再定義介電層:6以 ϋ尸t 能裸露於外° #利用電鍍方式沈積導 -¾金屬而形成金屬覆蓋層48(託1&1 capped iayer),此 屬覆蓋層48係用以與1/0焊墊形成電氣連接,而上述全屬
第11頁 517360 五、發明說明(9) 覆盍層可以是鋁、銅、鋁合金或是銅合金等金屬之一,其 中形成金屬覆盍層48的方法並不限於電鍍方式,也可以其 他方式,如網版印刷或是鋼版印刷等方式製成。
金屬覆蓋層4 8形成後,則接著覆蓋第一彈性層5 〇,可 以印刷、旋轉塗覆(spin coating)製程或黏合等方式之一 將一層厚度約為4〜20 "m的第一彈性層50覆蓋於矽晶圓基 板42之頂部’此第一彈性層5〇係由D〇w c〇rning HIPEC
Ql-4939 、D〇w Corning HIPEC SDA 6501 或Shin Etsu KJR9050E等材料之一製成,第一彈性層5〇厚度可控制在 4〜2 0 // m之間。 ’ 本發明亦提供一種製程,可不用鍍上金屬覆蓋層4 8, 如第一 I / 0焊塾4 4的頂面4 9的部分。如果製程為銘導線製 程’則可不需要金屬覆蓋層,如此,即可免去上述金屬覆 蓋層4 8的製程。 接著,請參考第3B圖,在第一彈性層5 〇形成之後,即 對第一彈性層5 〇之頂面進行回钱刻製程以使金屬覆蓋層4 8 的頂面能裸露於外,並在部份第一彈性層5 〇上以印刷方式 形成一厚度約為4〜1 〇 〇 # m的第二彈性層5 2,形狀例如為分 離成島狀的複數個圓丘狀(k η 〇 b t y p e )圖,材質同樣可與 第一彈性層50 相同由Dow Corning HIPEC Ql-4939、Dow Corning HIPEC SDA 6 5 0 1 或Shin Etsu KJR9 0 5 0E 等材料之 一製成,此第二彈性層52由後續的製程可知為第二;[/0焊 墊形成所在的區域。 清繼續參考第3C圖,金屬導線成型(patterning),在
第12頁 517360 五、發明說明(10) 一·一一 t 此步驟中係利用一光微影技術將第一 I /〇焊墊^由積體電 路晶粒的四周延伸至晶粒的中心,亦即藉由進行一埠端重 佈(I/O Pad RecHstnbution)以使多個第二1/〇焊墊能排 列於第一彈性層5 2區域上的晶粒表面。而在進行埠端重佈 製程時,必需先在第一、第二彈性層5〇、52之頂部沈積一 V包層,其沈積的方式可以利用濺鍍方式將高導電性金屬 (#例如銅或鋁)形成於第一、第二彈性層5 〇、5 2之頂部,接 著再以傳統的光微影技術定義導電層以形成一金屬線54。 在此步驟中係藉由金屬線54 —端與金屬覆蓋層“的導接並 延伸另一知至第一彈性層5 2上,而使I / 〇焊墊能由積體電 路日日粒之四周延伸至晶粒的中心。如果沒有金屬覆蓋層 4 8 ’則直接將金屬線連接至I / 〇焊墊上。 請繼續參照第3D圖,在金屬線54形成之後,於矽晶圓 基板4 2之頂部沈積一絕緣層以作為一保護層 56(PlSS1Vatlon),材質可選擇彈性體、PI或BCB。保護層 56覆蓋整個矽晶圓基板42表面,只露出第二彈性層52上的 金屬線54端欲形成第二1/〇焊墊58的窗口。形成上述保護 層56的方法有很多,例如可先於欲形成第二〗/〇焊墊58的 金屬線54位置上先上一層光阻柱(pR stud)後再形成保護 層5 6,待光阻柱及其上的部份保護層除去之後即可。或 ^ 也可在形成保護層5 6後再以微影技術曝露出第二I / 〇 焊墊58,甚至直接以雷射移除方式形成此窗口;接著再於 保護層56之頂部沈積一UBM層6〇並定義此υβΜ層6〇以使 層60,、沈積於第二1/〇焊墊58的上方,其中沈積層㈤的
517360 五、發明說明(11) 方法可以藉由無電鑛或是薄膜沈積等方式之一達成。 袁後’在形成U Β Μ層6 0之後,可利用網版印刷、鋼版 印刷、電沈積、無電沈積或是焊料球取放等技術在UBM層 6 0之上方形成一焊料凸塊(未標示),再經重流製程使焊料 凸塊因内聚力而形成一焊料球62,至此即將矽晶圓基板42 上所有的晶粒4 0同時加以封裝。 必須注意的是,在第r3A〜3D」圖的製程中,如果金 屬導線為鋁,則可免除第3 A圖中的金屬覆蓋層的製程, 3B〜3D當中的金屬覆蓋層同樣可免除。 少在本發明所揭露的製造方法中,係利用金屬線48當作 第一 I/O焊墊44與第二1/0焊墊58之間的電氣連接,而位於 金屬線48下m、第二彈性層5Q、52是被當成應力緩 衝層,藉由此應力緩衝層而能夠製造高可靠度已積 體電路晶片。 「圖4A〜4D」 4B」所示,印刷上 3 B」不同。至於之 同的方式,因此可 裝架構。 與上述的製程相同, 的第二彈性層52為一 後「圖4C〜4D」的製 苓照前述的内容製成 不再贅述,由「圖 圓丘形狀,與「圖 程步驟也是依照相 最後「圖4D」的構 雖然本發明已以較佳實施 限定本發明,任何熟習此技藝 和範圍内,當可作些許之更動 範圍當視後附之申請專利範圍 例揭露如上,然其並非用以 者’在不脫離本發明之精神 與潤飾,因此本發明之保護 所界定者為準。
517360 圖式簡單說明 第1 A〜1 B圖為習知之晶圓級構裝結構之剖面圖; 第2 A〜2B圖為本發明之增益型晶圓級構裝之結構剖面 圖; 第3 A〜3 D圖為本發明之增益型晶圓級構裝之結構的製 造方法之製程剖面圖;及 第4A〜4D圖為本發明之增益型晶圓級構裝之結構的製 造方法之製程剖面圖。 【圖式符號說明】 10 晶粒 12 秒晶圓基板 14 第一 I / 0焊墊 16 介電層 18 導電金屬柱 20 第一彈性層 22 第二彈性層 24 金屬線 26 保護層 28 第二I / 〇焊墊 30 _層 32 焊料球 35 接合處 40 晶粒 42 石夕晶圓基板 44 第一 I/O焊墊
第15頁 517360 圖式簡單說明 46 介電層 48 金屬覆蓋層 49 頂面 50 第一彈性層 52 第二彈性層 54 金屬線 56 保護層 58 第二I/O焊墊 60 UBM層 62 焊料球
Claims (1)
- 517360 六、申請專利範圍 1. 一種增益型晶圓級構裝之結構,包含: 一具有複數個積體電路晶粒的石夕晶圓基板,每一該 晶粒具有至少一第一 I /0焊墊; 一第一彈性層,形成於該矽晶圓基板上,使該第一 I/O焊墊之頂面能露出; 一第二彈性層,形成於未有該第一 I / 〇焊墊的部份 該第一彈性層上; 複數個金屬線,各具有一第一末端覆蓋於該第一 I / 0焊墊,及自該第一末端延伸出形成於該第二彈性層 上的一第二末端; 一保護層,形成於該金屬線表面; 複數個露出表面的第二I / 0焊墊,分別形成於該金 屬線之該第二末端以形成導通;及 複數個焊料球,分別形成於該第二I / 0焊墊上以形 成導通。 2. 如申請專利範圍第1項所述之增益型晶圓級構裝之結 構,該複數個金屬線之材料係為铭。 3. 如申請專利範圍第1項所述之增益型晶圓級構裝之結 構,該複數個金屬線之材料係為銅。 4. 如申請專利範圍第1項所述之增益型晶圓級構裝之結 構,更包含複數個金屬覆蓋層,各別形成於每一該晶粒 的該第一 I / 0焊墊上以與該複數個金屬線形成導通。 5. 如申請專利範圍第1項所述之增益型晶圓級構裝之結 構,其中該第一及第二彈性層為一揚式模數(Young’ s第17頁 517360 六、申請專利範圍 module)小於6評3的彈性材料層。 6.:申ΐ! ί利範圍第1項所述之增益型晶圓級構裝之結 丄/弟一彈性層形成的厚度約為4〜20微米("m)。 =申請”範圍第i,所述之增益型晶圓、級構裝之結 β 4 * ΐ ΐ 一彈性層形成的厚度約為4〜1 0 0微米("m)。 • Ϊ申Μ利範圍第1項所述之增益型晶圓級構裝之結 i 亥^料球包含—覆晶球下金屬層(UBM),係形成於 该弟二I / 〇焊墊上。 ^申二f利範圍第1項所述之增益型晶圓級構裝之結 μ第及第二1 / 〇焊墊材料為選自銅、鋁、鋁合金 或銅合金材質中任一者。 。 11· 10 · 士申二專利範圍第1項所述之增益型晶圓級構裝之結 構第二彈性層為形成一圓丘狀的圖案。 如申睛專利範圍第1項所述之增益型晶圓級構裝之結 構’ 3亥第二彈性層為形成分離成島狀的複數個圓丘狀 圖案。 12 種晶圓級構裝的製造方法,包含下列步驟: k ί、 Ζ夕晶圓基板,其表面形成有複數個積m # 故日— 、収弘 日日祖’母一該晶粒具有至少一個第一 I / 0焊墊; 形成一第一彈性層於該矽晶圓基板上,並使 一 I/O焊墊之表面露出; 亥弟 ^ 形成一第二彈性層於未有該第一 I /〇焊墊的部份該 第一彈性層; ~ 形成至少一個金屬線,具有一第一末端覆蓋於誃第18頁 517360 六、申請專利範圍 ,其中該第二彈性層係以一印刷(p r i n t i n g )製程形 成。 2 1.如申請專利範圍第1 2項所述之晶圓級構裝的製造方法 ,其中該第二彈性層的厚度約為4〜1 0 0微米(// πι)。 2 2.如申請專利範圍第1 2項所述之晶圓級構裝的製造方法 ,其中該第二彈性層係形成一圓丘狀的圖案。 2 3.如申請專利範圍第1 2項所述之晶圓級構裝的製造方法 ,其中該第二彈性層為形成分離成島狀的複數個圓丘 狀圖案。 2 4.如申請專利範圍第1 2項所述之晶圓級構裝的製造方法 ,其中形成該焊料球之前,更包含形成一覆晶球下金 屬層(UBM)於該第二I/O焊墊上。 2 5.如申請專利範圍第1 2項所述之晶圓級構裝的製造方法 ,其中該焊料球係以一網版印刷、鋼版印刷、電沈積 、無電沈積或是焊料球取放等技術之一形成。第20頁
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