200403290 玖、發明說明： 【發明所屬之技術領域】 本發明係關於活化並金屬化聚合物基板（特別是芳香族 聚合物基板）之改良方法。 【先前技術】 由芳香族聚合物製造含芳香族聚合物之基板常用於某些 電子組裝（如微電子封裝）之結構。已發現大量聚合物滿足這 \ 類基板之使用。已發現聚醯亞胺特別適合此使用，部分因 為其極佳之熱安定性及對溶液之抵抗力。 芳香族聚合物（如聚醯亞胺）在微電子封裝施用（如可彎曲 (彎曲）電路、堅硬彎曲電路、印刷電路板（PCB)、多層彎曲 電路及>5夕晶片上之鈍化層）廣泛使用。然而，這些芳香族聚 合物本身傾向與鍍在其上之金屬（如銅、鎳及金）之黏著性不 佳。因此，必須發展改良這類金屬及這些基板間黏著性之 某種技術。已採用幾種方法以嘗試克服不良黏著性之問題。 例如’黏著劑常用於結合金屬層在這些聚合物薄膜上， 藉以製造金屬覆蓋聚合物薄膜。微影術一般用於使金屬層 有圖案。然而，有這些覆蓋薄膜完成細線路是困難的因為 蝕刻金屬層導致線路中側蝕（因在光罩下之蝕刻）且因需要 具分離操作之機械強度之事實金屬層需較厚（至少15微米） 。此外使用之黏著劑造成雷射鑽微通孔之困難。且亦浪費 金屬。 嘗試改良黏著性之另一方法為塗佈液體聚醯亞胺（或其 前驅物聚酿胺酸在粗糙金屬箔（如銅箔），隨後硬化。然而， -6- 85893 200403290 細線路再次因金屬箔之厚度不易達成。 嘗試改良黏著性之另一已知方法為測鍍薄層鉻在聚合物 表面。薄層銅之後濺鍍在鉻層上。之後用電鍍增厚銅層。 雖然此法能產生細線路（在電鍍步騾前使用光阻），濺鍍步騾 為昂貴且消耗時間的。 在所有上面之方法中，鑽通過金屬塗佈層之微通孔是困 難的。在鑽孔後，微通孔亦需要分離地電鍍。 製造金屬覆蓋聚合物薄膜之另一技術為無電電鍍。然而 ，聚合物表面需要以觸媒活化（晶種）以引起無電電鍍。例如 ，頃發現免（Pd)為引起無電電鍍最有效之觸媒。 本發明針對活化無電電鍍之聚合物基板達成基板及隨後 施用之金屬塗層間良好黏著性之改良方法。 【發明内容】 根據本發明之第一具體實施例，提供一種活化及金屬化 芳香族聚合物薄膜之方法，其包括步騾： •以鹼溶液處理薄膜之第一表面； •將含聚合物安定觸媒粒子之水溶液晶種液施用至該第一 表面；及 •將該薄膜浸在含所需金屬之離子的無電電鍍浴中以沈積 該金屬層於該薄膜之第一表面上。 鹼溶液為氫氧化鈉（NaOH)較佳，或為氫氧化鉀（KOH)。 對此溶液較寬範圍之濃度為適當的（如0.2至2M)。鹼溶液可 藉將薄膜浸在鹼溶液之浴中施用。另一選擇為鹼溶液可噴 灑一層溶液在薄膜之第一表面上施用。欲活化之薄膜表面 應維持與鹼溶液接觸特定之期間（視鹼溶液之莫耳濃度與 200403290 溫度而定，例如室溫下1MKOH溶液為1至15分鐘）。在浸入 (或噴灑）後，洗去驗溶液（用去離子水較佳）。驗溶液之施用 典型在攝氏20°至60°之溫度下進行。 在一些情況中，在以鹼溶液（如KOH)處理聚合物薄膜後 ，聚合物薄膜隨後以質子化形成在表面上之羧酸根離子的 酸溶液處理。藉將KOH處理過之薄膜浸在水溶液酸液特定 之期間（如2至20分鐘）完成。稍後以去離子水清洗並乾燥 (通常用流通空氣）。 水溶液晶種溶液以含有聚合物安定鈀粒子。此安定可藉 水溶性聚合物（如聚乙晞吡咯啶（PVP)或聚乙烯醇（PVA)，雖 然以PVP特佳）作用。 典型上上述鈀粒子之直徑將為1至50 nm，以2至10 nm更 佳。 水溶液晶種溶液典型上藉將薄膜浸在晶種溶液浴中施用 至薄膜上。此浸泡典型上為2至60秒。在此之後，薄膜由浴 中移除且移除過量之晶種溶液，以去離子水清洗較佳。 合適之金屬典型上係選自由鎳、銅及金組成之群。因此 ，無電電鍍浴將含特別合適金屬之離子。 在合適金屬層沈積在薄膜上後，薄膜以去離子水清洗較 佳之後乾燥。 在沈積金屬層後或在隨後之清洗並乾燥後，薄膜可加熱 以進一步改良薄膜及金屬層間之黏著性。 上面方法可施用至薄膜之第一表面、薄膜之第二表面或 二表面° 85893 200403290 芳香族聚合物薄膜由聚酿亞胺（如卡普頓（Kapt〇nTM)膜）形 成特佳。 頃發現形成通過（或基本上通過）薄膜之微通孔在施用鹼 溶液之前特佳。這些微通孔使用雷射鑽孔、機械鑽孔或藉 化學姓刻之已知方法鑽孔通過或進入薄膜中。之後薄膜經 鹼溶液及晶種溶液處理（如上所述）。在這些處理中，微通孔 之側壁同時與薄膜之表面活化。在晶種步驟中，聚合物安 定觸媒粒子吸附上薄膜表面上以及在微通孔之侧壁上。相 似地，在金屬化步驟中，合適之金屬塗佈在薄膜表面上以 及微通孔之側壁上。因此，此方法除去微通孔典型上在形 成電路圖案後鑽孔且需要與電之其餘部分分開電鍍之本發 明方法中之一個步驟。 在薄膜之化學處理前形成聚合物中之微通孔特別有利。 例如，當聚合物薄膜之二表面皆塗佈合適之金屬時，微通 孔亦將塗佈合適之金屬，藉以連接在聚合物薄膜之相反表 面上金屬鍍層。 在本發明之較佳觀點中，在以鹼溶液處理薄膜之前，薄 膜可塗佈光阻。之後合適之電路可使用光阻上之光罩界定 。之後顯影光阻以暴露與所需電路圖案一致之薄膜表面之 部分。之後暴露之薄膜表面可如上所述處理並金屬化藉以 使選擇性金屬化產生薄膜上所需之電路圖案。因此，在光 阻及隨後之曝光製版之協助，所需之線路可藉選擇性金屬 電鍍形成在聚合物。 圖1圖示根據本發明較佳具體實施例製造雙面彎曲電路 85893 200403290 之形成。 如圖所示乾淨卡普頓1之薄膜有通過此薄膜之形成微通 孔2。之後薄膜1之兩個相對面3 a、3 b經強驗溶液液（如KOH) 化學處理，隨後以聚合物安定鈀粒子之膠狀懸浮液活化。 薄膜1之側壁4同時化學處理及活化。 之後將活化之薄膜置於無電電鏡浴（如無電銅浴），其使金 屬銅5之層形成在薄膜之表面3a、3 b上及微通孔2之側壁4。 之後處理鍍過之薄膜以施用形成電路之圖案。為了完成 此過程，以所需之圖案施用光阻6。另一選擇為可施用無圖 案條狀光阻材料至表面之後此條狀光阻接受顯影（如藉使 用光罩及蝕刻步驟以產生所需圖案之光阻）。 之後鍍過之薄膜可接受電鍍以產生形成在銅層5上之金 屬化電路7。 之後藉例如已知之蝕刻方法移除光阻6。 之後成層之薄膜接受進一步之蝕刻以移除電路7間之無 電電鍍銅層。 根據上面之本發明，聚合物薄膜可藉使用微分配機器而 不使用任何光阻光罩以制式圖案之形式鍍上所需之金屬。 在此具體實施例中，氫氧化鉀水溶液以小滴之形式分配到 乾淨聚合物薄膜上。在約5至1()分鐘後，聚合物以去離子水 m洗之後以壓鈿空氣乾燥。之後薄膜在以去離子水清洗及 &晶種溶液處理。這造成薄膜在氫氧化卸溶液分配 〈處理選擇性晶種。之後薄膜經過足以使所需量之金屬沈 積在薄膜上之時間的無電電鍍。這使金屬只選擇性鍍在薄 85893 -10- 200403290 膜之活化區域上。如圖2及3所示，這容易形成之金屬圖案 (在聚合物上以微小圓圈10之形式）可用於形式球腳格狀列 陣（BGA)封裝之金屬墊。 本發明亦施用在矽晶圓上連接墊之重新分配。芳香族聚 合物薄膜廣泛使用作矽晶片上之鈍化層。藉使用本發明， 晶片周圍上之連接塾可在其表面上重新分配。 因此，本發明提供以所需之金屬無電塗佈在芳香族聚合 物薄膜表面上之另一種方法。本發明方法亦使具所需微通 孔之電路比先前之情況更簡單且方便地製造。 【實施方式】 實例： (i)為了展示之目的，使用5密爾厚之卡普頓，其為如圖4 所示之通式代表由苯四甲酸二酐（PMDA)及4-4’二胺基 二苯基醚（或氧二笨胺，ODA)製造之商業聚醯亞胺。在 室溫下以1M水溶液氫氧化鉀（KOH)液處理10分鐘。 KOH攻擊聚醯亞胺中醯亞胺基形成聚醯胺酸之鉀鹽。 薄膜以去離子（DI)水澈底清洗以移除過量KOH之後使 用壓縮空氣流乾燥。經鹼處理之卡普頓薄膜之後在室 溫下與0.2M氫氯酸（HC1)液接觸10分鐘隨後以DI水清 洗並乾燥。此化學處理形成卡普頓表面上之聚醯胺酸 ，導入羧酸基團。 如何製備以聚乙晞吡咯酮（PVP)安定之鈀粒子水溶液懸 浮液之實例如下： 溶解150 mg之PVP(重量平均分子量=50,000，雖然其 -11- 85893 200403290 可為10,000至約500,000間之任何值）於〇1水中。 溶解 150 mg之PdCl2於5·25 ml之HC1(〜37%純）中。 混合PVP及PdCl2溶液。 緩慢添加10 ml_35 ml之次磷酸（H3〇2P)(50%純）至溶液 中。 添加DI水直到溶液總體積為1升。 之後經化學處理之卡普頓薄膜浸在聚乙晞吡啶酮（ρνρ) 之水溶液懸浮液塗佈把粒子3 〇秒，之後以DI水清洗並乾 燥。 乂後此Pd觸媒活化卡普頓薄膜在mi無電銅電鍍ι5_6〇 分鐘。薄層（1-2 μιη)之銅鍍在卡普頓上。 (11)除了使用無電鎳鍍浴在8(TC鍍薄層（1-2 μιη)鎳約15-3〇 分鐘之外按照實例⑴之步騾。 對本發明之許多改變及修正而不達背其精神及範圍對熟 苟此藝者為容易明顯的。 在本說明書中，除了另有指明，詞「包括」指「包含」 換β之’當本發明敘述或定義為包括某種特徵或元件時 應了解本發明包含（至少）這特徵或元件但亦可（除非文字 另外指明）包括其他特徵或元件。 【圖式簡單說明】 本發明之較佳具體實施例已參照附圖敘述，其中： 圖1為圖示描述根據本發明較佳具體實施例活化及金屬 化万香族聚合物薄膜之二相反表面之方法。 圖2為顯示聚醯亞胺薄膜相片之放大部分，上面一系列之 85893 -12· 200403290 鎳墊根據本發明之方法形成。 圖3為圖2中所示之塗佈聚醯亞胺薄膜部分之進一步放大。 圖4顯示商業上之聚醯亞胺卡普頓之化學式。 【圖式代表符號說明】 1 薄膜 2 孔 3a 薄膜表面 3b 薄膜表面 4 側壁 5 金屬銅層 6 光阻 7 金屬化電路 -13- 85893.doc200403290 (1) Description of the invention: [Technical field to which the invention belongs] The present invention relates to an improved method for activating and metallizing a polymer substrate (especially an aromatic polymer substrate). [Previous technology] Aromatic polymer-containing substrates made from aromatic polymers are often used in some electronic assembly (such as microelectronic packaging) structures. A large number of polymers have been found to meet the needs of such substrates. Polyimide has been found to be particularly suitable for this use, in part because of its excellent thermal stability and resistance to solutions. Aromatic polymers (such as polyimide) are used in microelectronic packaging (such as bendable (flexible) circuits, rigid flex circuits, printed circuit boards (PCBs), multilayer flex circuits, and passivation layers on> 5x wafers) widely used. However, these aromatic polymers themselves tend to have poor adhesion to metals such as copper, nickel, and gold plated thereon. Therefore, it is necessary to develop a technique for improving the adhesion between such metals and these substrates. Several methods have been used in an attempt to overcome the problem of poor adhesion. For example, 'adhesives' are often used to bond metal layers to these polymer films to make metal-coated polymer films. Lithography is commonly used to pattern metal layers. However, it is difficult to complete fine lines with these cover films because the etching of the metal layer causes side etching in the circuit (due to etching under the photomask) and due to the fact that the mechanical strength of the separation operation is required to be thicker (at least 15 microns) ). In addition, the adhesive used makes it difficult to drill micro-vias. It also wastes metal. Another method to try to improve the adhesion is to coat liquid polyimide (or its precursor polyvinylamino acid) on rough metal foil (such as copper foil), and then harden. However, -6- 85893 200403290 fine lines again due to metal The thickness of the foil is not easy to achieve. Another known method to try to improve adhesion is to measure a thin layer of chromium on the polymer surface. A thin layer of copper is then sputtered on the chromium layer. The copper layer is then thickened by electroplating. Although this method can Generate fine lines (use photoresist before the plating step), the sputtering step is expensive and time consuming. In all of the above methods, it is difficult to drill micro through holes through the metal coating. After drilling Micro-vias also need to be separately plated. Another technique for making metal-clad polymer films is electroless plating. However, the polymer surface needs to be activated by a catalyst (seed) to cause electroless plating. For example, Pd ) Is the most effective catalyst for electroless electroplating. The present invention is directed to an improved method for activating electroless electroplated polymer substrates to achieve good adhesion between the substrate and the subsequently applied metal coating. [Summary of the Invention] According to A first embodiment of the invention provides a method for activating and metallizing an aromatic polymer film, comprising the steps of: • treating a first surface of the film with an alkali solution; • crystallizing an aqueous solution containing polymer stable catalyst particles A seed solution is applied to the first surface; and the film is immersed in an electroless plating bath containing ions of the desired metal to deposit the metal layer on the first surface of the film. The alkali solution is sodium hydroxide (NaOH) Preferably, or potassium hydroxide (KOH). A wide range of concentration of this solution is appropriate (such as 0.2 to 2M). The alkali solution can be applied by dipping the film in a bath of alkali solution. Another option is alkali The solution can be sprayed with a layer of solution on the first surface of the film. The surface of the film to be activated should be maintained in contact with the alkaline solution for a specific period of time (depending on the molar concentration of the alkaline solution and the temperature of 200303290, for example, 1MKOH solution at room temperature is 1 To 15 minutes). After immersion (or spraying), wash the test solution (preferably with deionized water). The test solution is typically applied at a temperature of 20 ° to 60 ° Celsius. In some cases, in the Alkaline solution After treating the polymer film (such as KOH), the polymer film is then treated with an acid solution of carboxylate ion protonated on the surface. By immersing the KOH-treated film in an aqueous acid solution for a specific period (such as 2 to 20) Minutes) completed. Rinse with deionized water and dry (usually with circulating air). Aqueous seed solution to stabilize the polymer with palladium particles. This stability can be obtained by water-soluble polymers such as polyethylene pyrrolidine (PVP) Or polyvinyl alcohol (PVA), although PVP is preferred. Typically, the diameter of the above-mentioned palladium particles will be 1 to 50 nm, and more preferably 2 to 10 nm. This solution is applied to the film in a bath. This immersion is typically 2 to 60 seconds. After that, the film is removed from the bath and the excess seed solution is removed. It is preferred to wash with deionized water. Suitable metals are typically selected from the group consisting of nickel, copper and gold. Therefore, electroless plating baths will contain particularly suitable metal ions. After a suitable metal layer is deposited on the film, the film is preferably washed with deionized water and then dried. After the metal layer is deposited or after subsequent cleaning and drying, the film can be heated to further improve the adhesion between the film and the metal layer. The above method can be applied to the first surface, the second surface, or both surfaces of the film. 85893 200403290 The aromatic polymer film is particularly formed from a polyimide (such as KaptonTM film). It was found that the formation of micro-vias through (or substantially through) the film was particularly preferred prior to the application of the alkaline solution. These micro-vias are drilled through or into the film using laser, mechanical, or chemically known methods. The film is then treated with an alkaline solution and a seed solution (as described above). In these processes, the sidewalls of the micro-vias are simultaneously activated with the surface of the film. In the seeding step, polymer-stable catalyst particles are adsorbed on the film surface and on the side walls of the micro-vias. Similarly, in the metallization step, a suitable metal is coated on the surface of the film and on the sidewalls of the micro-vias. Therefore, this method removes micro-vias which are typically drilled after the circuit pattern is formed and requires one step in the method of the present invention which requires electroplating separately from the rest of the electricity. It is particularly advantageous to form micro-vias in the polymer prior to chemical treatment of the film. For example, when both surfaces of the polymer film are coated with a suitable metal, the micro-vias will also be coated with a suitable metal to connect the metal plating on the opposite surface of the polymer film. In a preferred aspect of the present invention, the film may be coated with a photoresist before the film is treated with an alkali solution. A suitable circuit can then be defined using a mask on the photoresist. The photoresist is then developed to expose a portion of the film surface consistent with the desired circuit pattern. The surface of the film that is subsequently exposed can be treated and metallized as described above to selectively metallize to produce the desired circuit pattern on the film. Therefore, with the assistance of photoresist and subsequent exposure lithography, the required circuits can be formed on the polymer by selective metal plating. FIG. 1 illustrates the formation of a double-sided flex circuit 85893 200403290 according to a preferred embodiment of the present invention. As shown in the figure, the film of Clean Kapton 1 has micro-vias 2 formed through the film. The two opposite sides 3a, 3b of the film 1 are then chemically treated with a strong solution (such as KOH), and then activated with a colloidal suspension of polymer stable palladium particles. The sidewalls 4 of the film 1 are simultaneously chemically treated and activated. The activated film is then placed in an electroless microscopy bath (such as an electroless copper bath), which forms a layer of metal copper 5 on the surfaces 3a, 3b of the film and the side wall 4 of the micro-via 2. The plated film is then processed to apply a circuit-forming pattern. To accomplish this, a photoresist 6 is applied in the desired pattern. Another option is to apply a pattern-free strip-shaped photoresist material to the surface after the strip-shaped photoresist is developed (for example, by using a photomask and an etching step to produce the desired pattern of photoresist). The subsequently plated film may be electroplated to produce a metallization circuit 7 formed on the copper layer 5. The photoresist 6 is then removed by, for example, a known etching method. The layered film is then subjected to further etching to remove the electroless copper plating layer between the circuits 7. According to the above invention, the polymer film can be plated with a desired metal in the form of a pattern by using a micro-dispensing machine without any photoresist mask. In this embodiment, the aqueous potassium hydroxide solution is dispensed in the form of droplets onto a clean polymer film. After about 5 to 1 () minutes, the polymer was washed with deionized water and dried with compressed air. The film was then washed with deionized water and treated with & seed solution. This results in the distribution of the thin film in the hydroxide degassing solution. The film is then subjected to electroless plating for a time sufficient to allow the required amount of metal to deposit on the film. This allows the metal to be selectively plated only on the activated area of the thin 85893-10-200403290 film. As shown in Figures 2 and 3, this easy-to-form metal pattern (in the form of a tiny circle 10 on the polymer) can be used as a metal pad for a form-ball grid array (BGA) package. The invention also applies to the redistribution of connection pads on silicon wafers. Aromatic polymer films are widely used as passivation layers on silicon wafers. By using the present invention, the connections on the wafer periphery can be redistributed on its surface. Accordingly, the present invention provides another method for electrolessly coating the surface of an aromatic polymer film with a desired metal. The method of the present invention also makes the circuit with the required micro-vias simpler and more convenient to manufacture than before. [Embodiment] Examples: (i) For the purpose of demonstration, a 5 mil thick Kapton is used, which is a general formula as shown in Figure 4 represented by pyromellitic dianhydride (PMDA) and 4-4 ' Commercial polyfluorene imine manufactured by aminodiphenyl ether (or oxodiphenylamine, ODA). It was treated with a 1M aqueous potassium hydroxide (KOH) solution at room temperature for 10 minutes. KOH attacks the amido group in polyimide to form the potassium salt of polyamidate. The film was washed with deionized (DI) water to remove excess KOH and then dried with a stream of compressed air. The alkali-treated Capton film was then contacted with 0.2M hydrochloric acid (HC1) solution at room temperature for 10 minutes, and then washed with DI water and dried. This chemical treatment forms polyamidic acid on the surface of Kapton and introduces carboxylic acid groups. An example of how to prepare an aqueous suspension of palladium particles stabilized with polyvinylpyrrolidone (PVP) is as follows: Dissolve 150 mg of PVP (weight average molecular weight = 50,000, although its -11- 85893 200403290 can be any between 10,000 to about 500,000) Value) in water. Dissolve 150 mg of PdCl2 in 5.25 ml of HC1 (~ 37% pure). Mix PVP and PdCl2 solution. Slowly add 10 ml_35 ml of hypophosphoric acid (H2O2P) (50% pure) to the solution. DI water was added until the total solution volume was 1 liter. The chemically treated Capton film was then dipped in an aqueous suspension of polyvinylpyridone (ρνρ) to coat the particles for 30 seconds, and then washed with DI water and dried. This Pd catalyst-activated Kapton film was then electroplated for 5-6 minutes on the electroless copper. A thin layer (1-2 μm) of copper is plated on Kapton. (11) Except for using an electroless nickel plating bath at 8 (TC plating thin layer (1-2 μm)) of nickel for about 15-30 minutes, follow the steps of Example 骡. Many changes and modifications to the present invention do not deviate from it. The spirit and scope are readily apparent to those skilled in the art. In this specification, unless otherwise specified, the word "includes" means "includes" instead of "β" when the invention is described or defined as including certain features or elements. It should be understood that the present invention includes (at least) this feature or element but may also (unless otherwise indicated in the text) include other features or elements. [Brief description of the drawings] The preferred embodiments of the present invention have been described with reference to the accompanying drawings, in which: 1 is a diagram describing a method for activating and metallizing the opposite surface of a vanilla polymer film according to a preferred embodiment of the present invention. Fig. 2 is an enlarged part showing a photo of a polyimide film. The above series of 85893- 12.200403290 Nickel pads were formed according to the method of the present invention. Figure 3 is a further enlargement of the polyimide-coated film portion shown in Figure 2. Figure 4 shows the chemical formula of a commercially available polyimide Kapton. Schema representation DESCRIPTION Number 3a 3b thin film surface of the thin film surface of the second hole sidewall 4 5 6 copper layer 7 a metallization resist circuit -13- 85893.doc