!255675 九、發明說明： 【發明所屬之技術領域】 本發明係提供—種印刷電路板之填孔方法，尤指-種 可以形成平㈣魏表^印㈣路板料孔方法。 【先前技術 近來，隨著積體電路（IC)積集度提高以及封f尺寸 =等趨勢，因此幾何尺寸精細與高密度線路佈局的印刷 思路板(PCB)便因應而生。而為了符合此 _ , 而衣，目前印刷 、線路積集度 毛路板大多係藉由多層結構來提高互連密度、 與電傳導效率。 如苐1圖所不，在多層印刷電路板1〇巾 習知多層印 剛电路板製程常會利用埋孔(buried via)ll鱼亡， • '、目孔（blind255675 IX. Description of the Invention: [Technical Field] The present invention provides a method for filling a printed circuit board, and more particularly, a method for forming a flat (four) Wei table (four) road plate material hole. [Prior Art Recently, with the increase in the integrated circuit (IC) and the size of the package, the printed circuit board (PCB) with fine geometry and high-density line layout has been born. In order to comply with this, the current printing and line accumulating degree of the hairboard are mostly increased by the multilayer structure to improve the interconnection density and electrical conduction efficiency. As shown in Fig. 1, in the multilayer printed circuit board, the conventional multilayer printed circuit board process often uses buried vias to die, • ', eye holes (blind
Vla)l2及13分別依其功能或配置的需求而 ^ 叹置於多層印刷 毛路板10中，用以電連接各層的導電線路。 丹中，傳導層 14、15及丨6係被塗覆於埋孔11及各盲孔l9 h 13之侧壁， 各盲孔12、13上方更形成有一電鍍銅層，用以填覆各盲孔 12、13。 、復目 或是孔的深寬比 然而，當孔徑大於4密爾（mil)以上， 1255675 (aspect ratio)大於0.4以上時，電鍍銅製程就會笋生填 孔隙或填孔後的表Μ平坦，如此便^再於並上' 形成疊孔(stack via)結構，以進一步提高印刷電路板表面白、 線路密度’而且盲孔的電性表現以及可靠度都會不佳、。勺 因此習知技術會先形成-傳導層於印刷電路板表面， 並使用-種網版印刷製程或是—健軋塗覆製程而於各孔 之孔隙間披覆以一種絕緣填充材料或導電環氧樹脂，進而 防止後製程遺留物蔓延污染並提供結構性的支撐:能。 印刷電路板 在上述這種網版印刷技術的填孔方法中 網版大多係利用複數條纖㈣線編織成互相穿越彼此而形 成-網格的構造’傳統式之纖細纜線的直徑約為〇 045到 謂mm，幾乎是各盲孔之直徑的—半，因此在此纖細繞線 交錯的部位中’各盲孔的部分容易會被覆蓋，進而造成塗 覆之不完全。 係被定位在-個夾具上’並利用像是網格的—個網版係被 定位在其上方侧邊的某-距離處’接著將絕緣材料彼覆在 網版的上方表面後，再藉著軸㈣心使1 緣材料經 由一個在網版中的開口排出而被填入印刷電路板盲孔中。 但是，由於現行各孔的直徑是介於〇1到〇 l5mm之間，而 !255675 另外，絕緣填充材料是藉著在將網版放置於印刷電路 板上之後，再推動被塗敷在網版上的絕緣材料而被塗覆柃 =刷電路板的盲孔卜目此t後續在進行钱積體電路的 两熱回流(reflow)時，殘留於絕緣材料内的空氣氣泡會被拂 出，亚且由於積體電路、絕緣材料與印刷電路板的熱膨騰 係數是不相同的，因而即使H緣材料係被填滿於各盲孔 中’周圍的積體電路圖樣以及絕緣材料亦可能因為熱應力 及前述氣泡排出等因素而被損壞。 【發明内容】 、本發明的主要目的在於提供一種印刷電路板之填孔方 法利於形成璺孔以提高印刷電路板表面的線路密度，並 能避免印刷電路板因高熱而造成損壞。 為達上述目的，根據本發明之較佳實施例，本發明提 I、種印刷電路板之填孔方法。首先提供一印刷電路板， 其包含有至少-個盲孔設於印刷電路板之—表面中，接著 在巧溫及真空的狀態下進行—壓合製程，以將例如b階段 stage)環氧_材料之—處於熔融狀態的絕緣板壓合 於印刷電路板之表面，並填人盲孔中，然後利用—研磨製 1255675 程以去除突出於盲孔之部分的絕緣板。 由於本發明係先將絕緣板填入盲孔中，然後再以研磨 等方式去除溢出孔外的部分絕緣板’如此可以確保填孔的 表面平整，因此在進行憂孔的雷射鑽孔時’便可避免雷射 光束因填孔的表面不肀整而產生不規則反射’造成疊孔孔 壁不平整。另外，更<避免在上錫球的過程中，因填孔的 表面不平整而造成缺陷。此外，因為本發明所填佈之盲孔， 其内部無空氣之殘留，玎以避免高熱狀態下，印刷電路板 之損壤。 為了使貴審查委員能更近一步瞭解本發明之特徵及 技術内容，請參閱以下有關本發明之詳細說明與附圖。然 而所附圖式僅供參考與輔助說明用，並非用來對本發明加 以限制者。 【實施方式】 '月參考第2圖至第7圖，第2圖至第7圖為本發明之卿 刷私路板之填孔方法的第—實施例示意圖。如第2圖所 ’、〃先hi、夕層印刷電路板20，其由印刷電路板22、 印刷電路板24、印刷恭玖此^ , 丨邓〗私路板26、印刷電路板28以及印刷 1255675 電路板30依序推β 電路…並且二Τ墨合所構成，各印刷電路板上均包含有 埋孔34將彼此電連接。 如第3圖所千 3〇進行雷射鑽孔二W_路板22騎刷電路板 印刷電路板2〇表面、成目孔36及目孔38 ’接著對多層 面粗化製程，❹力，盲孔36及38之側壁表面進行—表 及犯之侧壁表面::刷電路板2G表面以及盲孔％ 印刷電路板Μ表面^度，進而提昇化學銅或銅層對多層 側壁表面形成—層:2__孔36及38之 表面覆蓋一層電約^ 可以是—層化學鋼層 I 5 b所組成，接著進行一黑化製程，用 以於多層印刷電路板2〇與各盲孔36及38之銅層4〇表面 成層氧化膜42，以增加銅層4〇表面粗糙度。 、，第4 ®所不’於_高溫與真空的狀態下，將處於溶融 狀緣板44及46，例如B階段（B stage)環氧樹脂 材料所組成之絕緣板，分別壓合於印刷電路板22及3〇之 表面，並填入盲孔36以及38中。此壓合因處於真空之狀 怨下進行，所以盲孔36以及38内完全沒有氣體，絕緣板 44及46可以完全填滿盲孔36以及38，不會產生氣泡，因 1255675 此可以防止在後續的高溫製程中，因為高熱而使盲孔36以 及38中的氣體氣泡排出’進而破壞周圍的積體電路圖樣以 及絕緣材料。 如第5圖所不 ' ▼…q ΜI微的方法，去除凸 出於盲孔36以及38表面之絕緣板44及46，曝露出〜化 膜42表面，殘留於盲孔36以及38内之绍绘七〇 緣板44以及如 以絕緣插銷(Plug)45與絕緣插銷47表示，至此即可妒成平 坦的盲孔36及38表面而完成本發明之印刷電路板之填孔 方法。 此外，本發明之印刷電路板之填孔方法亦可適用於製備 疊孔(stackvia)結構。如第6圖所示，在完成第2圖至第5 圖的製程步驟後，接著再於印刷電路板22及3〇表面形成 電路48及50,其中，形成於絕緣插銷45與絕緣插銷47 表面之電路分別以電路49與電路51表示，然後，分別壓 合印刷電路板52及54。 然後如第7圖所示，分別對印刷電路板52及54進行雷 射鑽孔，形成盲孔56及58，以曝露出覆蓋形成於絕緣插 銷45與絕緣插銷47表面之電路49與電路51。由於本發 I255675 明之印刷電路板的填孔方法可以確保填孔後表面的平整， 斤以於盲孔36及38表面進行疊孔時，可避免雷射光束因 為表面之不平整，而產生不規則反射，造成盲孔56及58 孔壁的不平整。 另外’本發明之印刷電路板之填孔方法亦可適用於外表 面之上錫球製程。請參考第8圖至第1〇圖，第8圖至第 3為本發明之印刷電路板之填孔方法的第二實施例示意❿ 圖 ° ^ 0 乐8圖所示，進行完本發明之填孔方法，於印刷電 才反6 0 a 及62表面形成電路64及66，然後於印刷電路板 62表面均勻形成一層防焊劑層68及70。 9圖所示’然後利用例如钮刻之方式，於防焊劑層 及70形成開口 72及74，以曝露出部分之導線圖案、，此 4出之導線圖案部分即形成接觸墊76及78。 ❿ 由最後如第10圖所示，於接觸墊76及78表面形成一層 - 、、金或有機保焊劑（〇rganic S〇lder preservative，〇Sp)等 材料所構成之保護層8〇及82,並形成錫球84及86。由於 本1明之印刷電路孔之填孔方法可以確保填孔之表面的平 身欠 疋，因此錫球形成後，不會因孔面之不平整，而在錫球内 11 I255675 部產生氣泡，影響構裝之品質。 綜合上述說明， 高溫與真空的狀態下 板，分別壓合於印刷 有下列優點： 本發明之印刷電路孔之填孔方法於一 /處於㈣狀態_料環氧樹脂 路板表面並填人各盲孔中，因此具 L真空熱壓溶融狀態的B階段環氧樹脂板具 性，因此在真空狀態下，可以輕易填滿各種孔徑的^， 而且在使壁面龍的同時，不會在靠近表面位^ 才对脂外渗，具有優良的平整性； 2.填充材料於盲孔内形成一個沒有孔洞的“插鎖狀結 構，，，故能為盲孔壁面提供支撐和良好的熱導性和電導性， 不會因為空氣或其他氣體形成的孔洞會在填充的盲孔中形 成各種不同的隔離區，使貼近表面的孔洞引起後續製程的 問題； 3·填充材料係均勻填滿於各f孔内，故應能克服輕微的孔 壁鑛層缺陷，如突S或因盲孔電鐘產生的彎曲限制等； 4·熔融狀態之B階段環氧樹脂板的固化溫度係與封裝或 印刷線路板材料特性以及設計限制條件相符合，故能夠控 制溫度的下降迷度，以減少形狀的改變和對後續製程的影 響； … 12 I255675Vla) l2 and 13 are respectively placed in the multi-layer printing bristle board 10 according to the function or configuration requirements for electrically connecting the conductive lines of the layers. In Danzhong, the conductive layers 14, 15 and 6 are applied to the buried holes 11 and the sidewalls of the blind holes l9 h 13 , and an electroplated copper layer is formed on each of the blind holes 12 and 13 to fill the blinds. Holes 12, 13. , the reaming or the aspect ratio of the hole. However, when the pore diameter is greater than 4 mils and the 1255675 (aspect ratio) is greater than 0.4 or more, the electroplating copper process will fill the pores or fill the surface after filling. In this way, the stack via structure is formed to further improve the surface whiteness and line density of the printed circuit board, and the electrical performance and reliability of the blind vias are not good. So the prior art will form a conductive layer on the surface of the printed circuit board and use a screen printing process or a wet-coating process to coat the pores of each hole with an insulating filler or conductive ring. Oxygen resin, which prevents post-process residues from spreading and providing structural support: energy. Printed Circuit Board In the above-mentioned screen filling method of the screen printing technique, the screen is mostly formed by weaving a plurality of filaments (four) wires to form each other to form a grid structure. The diameter of the conventional slim cable is about 〇. From 045 to mm, it is almost half the diameter of each blind hole, so in the portion where the thin windings are staggered, the portions of the blind holes are easily covered, resulting in incomplete coating. The system is positioned on a fixture and uses a mesh-like system to be positioned at a certain distance from the upper side of the mesh. Then the insulating material is overlaid on the upper surface of the screen, and then borrowed. The shaft (4) core causes the 1 edge material to be filled into the blind holes of the printed circuit board by being discharged through an opening in the screen. However, since the diameter of the current holes is between 〇1 and 〇l5mm, and !255675, the insulating filler is applied to the screen by placing the screen on the printed circuit board. The upper insulating material is coated with 柃=blind hole of the brush circuit board. After the two heat reflows of the money integrated circuit, the air bubbles remaining in the insulating material will be thrown out. Moreover, since the thermal expansion coefficient of the integrated circuit, the insulating material and the printed circuit board are different, even if the H-edge material is filled in the blind holes, the surrounding integrated circuit pattern and the insulating material may be hot. The stress and the aforementioned bubble discharge are damaged. SUMMARY OF THE INVENTION The main object of the present invention is to provide a hole filling method for a printed circuit board which is advantageous for forming a pupil to increase the line density of the surface of the printed circuit board and to prevent damage of the printed circuit board due to high heat. In order to achieve the above object, in accordance with a preferred embodiment of the present invention, the present invention provides a method of filling a printed circuit board. Firstly, a printed circuit board is provided, which comprises at least one blind hole disposed in a surface of the printed circuit board, and then subjected to a pressing process in a state of temperature and vacuum to, for example, a b-stage stage epoxy. The insulating sheet of the material in a molten state is pressed against the surface of the printed circuit board and filled in the blind hole, and then the insulating plate which is protruded from the portion of the blind hole is removed by grinding - 1255,675. Since the invention first fills the insulating plate into the blind hole, and then removes part of the insulating plate outside the overflow hole by grinding or the like, it is ensured that the surface of the filling hole is flat, so when performing laser drilling of the hole of the hole. It is possible to prevent the laser beam from being irregularly reflected due to the irregular surface of the hole filling, which causes the wall of the stacked hole to be uneven. In addition, it is more desirable to avoid defects in the process of the upper solder ball due to uneven surface of the hole. In addition, because the blind holes filled in the present invention have no residual air inside, the printed circuit board is damaged in the high heat state. In order to provide a more detailed understanding of the features and technical aspects of the present invention, the following detailed description of the invention and the accompanying drawings. The drawings are for illustrative purposes only and are not intended to limit the invention. [Embodiment] 'Monthly reference to Fig. 2 to Fig. 7, Fig. 2 to Fig. 7 are schematic views showing the first embodiment of the method for filling holes of the private road board of the present invention. As shown in Fig. 2, the first hi, the lithographic printed circuit board 20, which consists of a printed circuit board 22, a printed circuit board 24, a printed copy of the ^, a 丨 〗 〖 private board 26, a printed circuit board 28, and printing 1255675 The circuit board 30 sequentially pushes the β circuit and is composed of two inks, each of which includes a buried hole 34 to be electrically connected to each other. As shown in Fig. 3, laser drilling is performed on two W_road plates 22, and the printed circuit board printed circuit board 2 〇 surface, the eye opening 36 and the eye hole 38' are then subjected to a multi-layer roughening process, force, The sidewall surfaces of the blind holes 36 and 38 are used to make the surface of the sidewall and the surface of the sidewall: the surface of the brushed circuit board 2G and the blind hole % of the surface of the printed circuit board, thereby enhancing the formation of a layer of chemical copper or copper layer on the surface of the multilayer sidewall The surface of the 2__ holes 36 and 38 is covered with a layer of electricity, which may be composed of a layer of chemical steel layer I 5 b, followed by a blackening process for the multilayer printed circuit board 2 and the blind holes 36 and 38. The surface of the copper layer 4 is layered with an oxide film 42 to increase the surface roughness of the copper layer. 4th, in the state of high temperature and vacuum, the insulating plates of the molten edge plates 44 and 46, such as B stage epoxy resin materials, are respectively pressed onto the printed circuit. The surfaces of the plates 22 and 3 are filled into the blind holes 36 and 38. Since the pressing is performed under vacuum, the blind holes 36 and 38 are completely free of gas, and the insulating plates 44 and 46 can completely fill the blind holes 36 and 38 without generating bubbles, which can be prevented by 1255675. In the high-temperature process, gas bubbles in the blind holes 36 and 38 are discharged due to high heat, thereby destroying the surrounding integrated circuit pattern and the insulating material. As shown in Fig. 5, the method of removing the holes 44 and 46 protruding from the surfaces of the blind holes 36 and 38 exposes the surface of the film 42 and remains in the blind holes 36 and 38. The seven-sided edge plate 44 and the insulating plugs 47 are shown as insulating pins (45) and the flat blind holes 36 and 38 are formed to complete the hole filling method of the printed circuit board of the present invention. Further, the hole filling method of the printed circuit board of the present invention can also be applied to the preparation of a stackvia structure. As shown in FIG. 6, after the process steps of FIGS. 2 to 5 are completed, circuits 48 and 50 are formed on the printed circuit boards 22 and 3, respectively, which are formed on the surface of the insulating plug 45 and the insulating plug 47. The circuits are represented by circuit 49 and circuit 51, respectively, and then printed circuit boards 52 and 54 are respectively pressed. Then, as shown in Fig. 7, the printed circuit boards 52 and 54 are respectively subjected to laser drilling to form blind holes 56 and 58 for exposing the circuit 49 and the circuit 51 which are formed on the surfaces of the insulating plug 45 and the insulating plug 47. Since the hole filling method of the printed circuit board of the present invention can ensure the flatness of the surface after the filling, when the holes are stacked on the surfaces of the blind holes 36 and 38, the laser beam can be prevented from being irregular due to the unevenness of the surface. The reflection causes unevenness in the walls of the blind holes 56 and 58. Further, the hole filling method of the printed circuit board of the present invention can also be applied to the solder ball process on the outer surface. Please refer to FIG. 8 to FIG. 1 , and FIG. 8 to FIG. 3 are schematic diagrams showing a second embodiment of a method for filling holes of a printed circuit board according to the present invention. FIG. In the hole filling method, the surface forming circuits 64 and 66 are formed on the surface of the printed circuit board 60, and then a solder resist layer 68 and 70 are uniformly formed on the surface of the printed circuit board 62. 9 is then shown to form openings 72 and 74 in the solder resist layer and 70, for example, by means of a button engraving to expose portions of the conductor pattern, which form contact pads 76 and 78. ❿ Finally, as shown in Fig. 10, protective layers 8〇 and 82 are formed on the surface of the contact pads 76 and 78 by a layer of -, gold or organic solder resist (〇Sp), such as 〇rganic S〇lder preservative (〇Sp). Tin balls 84 and 86 are formed. Since the hole filling method of the printed circuit hole of the present invention can ensure the flatness of the surface of the filling hole, after the solder ball is formed, no bubble is generated due to the unevenness of the hole surface, and bubbles are generated in the 11 I255675 portion of the solder ball, which affects the structure. The quality of the equipment. According to the above description, the plates under high temperature and vacuum state are respectively pressed and printed to have the following advantages: The hole filling method of the printed circuit hole of the present invention is on the surface of the (4) state epoxy resin road board and is filled with blindness. In the hole, the B-stage epoxy resin sheet with L vacuum hot-melt molten state can be easily filled under various vacuum conditions, and the wall surface dragon is not close to the surface position. ^ It has excellent flatness for lipid extravasation; 2. The filling material forms a "plug-in structure" in the blind hole without holes, so it can provide support and good thermal conductivity and conductance for the blind hole wall surface. Sex, no holes formed by air or other gases will form various isolation zones in the filled blind holes, so that the holes close to the surface cause problems in subsequent processes; 3. The filling material is evenly filled in each f hole Therefore, it should be able to overcome the slight hole wall ore defects, such as the sudden S or the bending limit caused by the blind hole clock; 4. The solidification temperature of the B-stage epoxy resin plate in the molten state and the package or printed circuit board Material characteristics and design constraints consistent, it is possible to control the temperature drop made of fans to reduce the shape change and the subsequent impact on the process; ... 12 I255675
發生破裂； 而且還能承受後面的熱循環過程， 發生破裂；Cracking occurs; and it can withstand the subsequent thermal cycling process, causing cracking;
清洗、銅蝕刻、拋光、電鍍特別是化學鍍銅等等；以及 7.能承受填充後的機械處理’如經各種平面化處理後不應 破壞盲孔的表面特性，或造成後製程材料殘留到印刷和蝕 # 刻製程中。 相較於習知技術，本發明之印刷電路孔之填孔方法可以 確保填孔的表面平整，因此在進行疊孔的雷射鑽孔時，可 避免雷射光束因填孔的表面不平整而產生不規則反射，造 成疊孔孔壁不平整。另外，更可避免在上鍚球的過程中， 因填孔的表面不平整而造成缺陷。此外，因為本發明所填 籲 佈之盲孔，其内部無空氣之殘留，可以避免高熱狀態下， 印刷電路板之損壞。 . 以上所述僅為本發明之較佳實施例，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。 13 1255675 【圖式簡單說明】 第1圖係為習知印刷電路板之填孔方法示意圖。 第2圖至第7圖為本發明之印刷電路板之填孔方法的第一 實施例示意圖。 第8圖至第10圖為本發明之印刷電路板之填孔方法的第二 實施例示意圖。 【主要元件符號說明】 10、 20 多層印刷電路板 11、 34 埋孔 12、 13、36、38、56、58 盲孔 14、15、16傳導層 17、18 電鍍銅層 22、24、26、28、30、52、54、60、62 印刷電路板 32、49 > 5 卜 64、66 電路 40 銅層 42 氧化膜 44 - 46 絕緣板 45 > 47 絕緣插銷 68 ^ 70 防焊劑層 72、74 開口 76 ^ 78 接觸墊 80、82 保護層 84、86 錫球 14Cleaning, copper etching, polishing, electroplating, especially electroless copper plating, etc.; and 7. can withstand the mechanical treatment after filling 'such as after various planarization treatments should not destroy the surface characteristics of the blind holes, or cause the post-process materials to remain Printing and etching # in the process of engraving. Compared with the prior art, the hole filling method of the printed circuit hole of the present invention can ensure the surface of the filling hole is flat, so that the laser beam can avoid the unevenness of the surface of the filling hole when performing the laser drilling of the stacked holes. Irregular reflections are generated, causing the walls of the stacked holes to be uneven. In addition, it is possible to avoid defects caused by uneven surface of the hole filling during the process of the upper ball. Further, since the blind hole of the present invention is filled, there is no residual air inside, and damage of the printed circuit board in a high heat state can be avoided. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the patent scope of the present invention are intended to be within the scope of the present invention. 13 1255675 [Simple description of the drawing] Fig. 1 is a schematic diagram of a hole filling method of a conventional printed circuit board. 2 to 7 are schematic views showing a first embodiment of a hole filling method of a printed circuit board of the present invention. 8 to 10 are views showing a second embodiment of the hole filling method of the printed circuit board of the present invention. [Major component symbol description] 10, 20 multilayer printed circuit board 11, 34 buried holes 12, 13, 36, 38, 56, 58 blind holes 14, 15, 16 conductive layers 17, 18 electroplated copper layers 22, 24, 26, 28, 30, 52, 54, 60, 62 Printed circuit board 32, 49 > 5 Bu 64, 66 Circuit 40 Copper layer 42 Oxide film 44 - 46 Insulation board 45 > 47 Insulation pin 68 ^ 70 Solder resist layer 72, 74 opening 76 ^ 78 contact pad 80, 82 protective layer 84, 86 solder ball 14