200834762 CN-9509003 22159twf.doc/n 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種凸塊結構及其製造方法，且特別 是有關於一種平頂凸塊（flat_bump)結構及其製造方法。 【先前技術】 復晶接合技術（flip chip interconnect technology)乃 _ 是一種將晶片（die)連接至一線路板的封裝技術，其主要 疋在晶片之多個接墊上形成多個凸塊（bump)。接著將晶 片翻轉（flip)，並利用這些凸塊來將晶片的這些接墊連接 至線路板上的接合墊（terminal)，以使得晶片可經由這些 凸塊而電性連接至線路板上。通常，凸塊具有若干種類型， 例如焊料凸塊、金凸塊、銅凸塊、導電高分子凸塊、高分 子凸塊等。 圖1A為習知的金凸塊的剖面圖，而圖1B為習知的金 凸塊的俯視圖。請參考圖1A與圖1β，習知的金凸塊結構 適於配置在一晶片110上，而此晶片11〇上已形成有多個 鋁接墊120 (圖1A與圖1B僅繪示一個鋁接墊）與一保護 ，130。其中，保護層13〇具有多個開口 13如，其分別暴 露各銘接塾120的-部份。此外，習知的金凸塊結構包括 一球底金屬層140與一金凸塊150，其中球底金屬層140 配置開口 130a内，並覆蓋部分保護層13〇。金凸塊15〇配 置於球底金屬層M0上。由於此金凸塊ls〇覆蓋於部分保 濩層130上方的球底金屬層14〇上，因此金凸塊具有 5 200834762 CN-9509003 22159twf.doc/n 一％狀凸起部150a，而這就所謂城牆效應（waUeffect)。 然而’此環狀凸起部15〇a會影響金凸塊15〇與其他承載器 (未繪不）之間的接合強度。此外，由於球底金屬層14〇 僅配置於金凸塊150的下方，因此當球底金屬層 140與金 凸塊150之間或是球底金屬層14〇與保護層13〇之間產生 裂缝時，此種習知的金凸塊結構便容易出現底切效應 (under cut effect) ° 【發明内容】 本發明提供-種平頂凸塊結構的製造方法，以改善城 牆效應。 本發明提供-種平頂凸塊結構，以改善底切效應。 本發明提出一種平頂凸塊結構的製造方法，其包括下 列步驟。首s，提供-基板’而基板具有多個接_一保 護層，其中保具有辣第―開口，且各第—開口分別 暴露出相對應之接狄-部分。在基板上形成—球底金屬 材料層，以覆蓋保護層與保護層所暴露出之接墊。在保護 層所暴露出之㈣上方之球底金屬材料層上形成多個平、頂 凸塊’其中各平頂凸塊的底面積小於相對應之第一開口的 底面積’且平頂凸塊_面為平面。_化球底金屬材料 層’以形❹個球底金屬層’其巾各球底金屬層的底面積 大於相對應之第一開口的底面積。 在本發明之一實施例中，形成平頂凸塊的步驟包括在 球底金屬材料層上形成—第_圖案化光阻層，且第一圖案 6 200834762 CN-9509003 22159twf.doc/n 化光阻層具有多個第二開口，分別暴露出保護層所暴露出 之接墊上方之球底金屬材料層。在第二開口内形平 塊。移除第一圖案化光阻層。 、 在本發明之一實施例中，形成球底金屬層的步驟包括 在球底金屬材料層上形成一第二圖案化光阻層，其中第二 圖案化光阻層覆蓋這些平頂凸塊，並暴露出部分球底金屬 材料層。圖案化球底金屬材料層，以形成球底金屬層。移 除第二圖案化光阻層。 在本發明之一實施例中，在形成球底金屬層的步驟 中，各球底金屬層的底面積大於相對應之第一開口的底面 積。 本發明提出一種平頂凸塊結構，其適於配置於一基板 上。此基板具有一接墊與一保護層，其中保護層具有一開 口’其暴露出接墊之-部分。此平頂凸塊結構包括一球底 金屬層與一平頂凸塊，其中球底金屬層配置於保護層上， 並覆盍保濩層所暴露出之接墊。平頂凸塊配置於接墊上方 之球底金屬層上，其中平頂凸塊的頂面為平面。此外，平 頂凸塊的底面積小關π的底φ積，且球底金屬層的底面 積大於開口的底面積。 在本發明之一實施例中，平頂凸塊的材質可以是金。 在本發明之一實施例中，接墊的材質可以是鋁。 在本發明之一實施例中，基板可以是晶片或晶圓。 基於上述，由於本發明將平頂凸塊形成於保護層的開 口内’因此此種平頂凸塊具有平坦的了頁面。此外，由於球 200834762 CN-9509003 22159twf.doc/n 因此此種平頂 底金屬層的底面積大於平頂凸塊的底面積， 凸塊結構較不易產生底切效應。 為讓本發明之上述特徵和優點能更明顯易僅 舉較佳實闕’並配合所關式，作詳細說明如下。 【實施方式】200834762 CN-9509003 22159twf.doc/n IX. Description of the Invention: [Technical Field] The present invention relates to a bump structure and a method of fabricating the same, and more particularly to a flat-bump structure and Its manufacturing method. [Prior Art] Flip chip interconnect technology is a packaging technology for connecting a die to a circuit board, which mainly forms a plurality of bumps on a plurality of pads of the wafer. . The wafers are then flipped and the bumps are used to connect the pads of the wafer to the terminals on the board so that the wafer can be electrically connected to the board via the bumps. Generally, there are several types of bumps, such as solder bumps, gold bumps, copper bumps, conductive polymer bumps, high molecular bumps, and the like. 1A is a cross-sectional view of a conventional gold bump, and FIG. 1B is a top view of a conventional gold bump. Referring to FIG. 1A and FIG. 1β, a conventional gold bump structure is suitable for being disposed on a wafer 110, and a plurality of aluminum pads 120 have been formed on the wafer 11 (FIG. 1A and FIG. 1B only show one aluminum). Pad) with a protection, 130. The protective layer 13A has a plurality of openings 13 such as, for example, exposing portions of the respective interfaces 120. In addition, the conventional gold bump structure includes a ball bottom metal layer 140 and a gold bump 150, wherein the ball bottom metal layer 140 is disposed in the opening 130a and covers a portion of the protective layer 13A. The gold bump 15 is placed on the metal layer M0 of the ball. Since the gold bump ls 〇 covers the ball metal layer 14 上方 above the partial 濩 layer 130, the gold bump has a % convex portion 150a of 200834762 CN-9509003 22159 twf.doc/n, and this The so-called wall effect (waUeffect). However, this annular projection 15a affects the joint strength between the gold bumps 15〇 and other carriers (not shown). In addition, since the ball bottom metal layer 14 is disposed only under the gold bump 150, a crack occurs between the ball bottom metal layer 140 and the gold bump 150 or between the ball bottom metal layer 14〇 and the protective layer 13〇. In this case, the conventional gold bump structure is prone to undercut effect. [Invention] The present invention provides a method for manufacturing a flat-top bump structure to improve the wall effect. The present invention provides a flat top bump structure to improve the undercut effect. The present invention provides a method of fabricating a flat-top bump structure comprising the following steps. The first s, the substrate is provided, and the substrate has a plurality of protective layers, wherein the first and second protective layers are provided, and each of the first openings exposes a corresponding contact portion. A layer of a spherical metal material is formed on the substrate to cover the pads exposed by the protective layer and the protective layer. Forming a plurality of flat and top bumps on the layer of the bottom metal material above the (4) exposed by the protective layer, wherein the bottom area of each flat top bump is smaller than the bottom area of the corresponding first opening and the flat top bump The _ face is a plane. The bottom layer of the metal material layer is formed to form a bottom metal layer of the ball. The bottom surface area of each of the ball bottom metal layers is larger than the bottom area of the corresponding first opening. In an embodiment of the present invention, the step of forming a flat top bump includes forming a -th patterning photoresist layer on the bottom metal material layer, and the first pattern 6 200834762 CN-9509003 22159twf.doc/n The resist layer has a plurality of second openings exposing the layer of the bottom metal material above the pads exposed by the protective layer. A flat block is formed in the second opening. The first patterned photoresist layer is removed. In an embodiment of the invention, the step of forming a ball-bottom metal layer comprises forming a second patterned photoresist layer on the ball-bottom metal material layer, wherein the second patterned photoresist layer covers the flat-top bumps, And a part of the bottom metal material layer is exposed. A layer of ball metal material is patterned to form a ball-bottom metal layer. The second patterned photoresist layer is removed. In an embodiment of the invention, in the step of forming the ball-bottom metal layer, the bottom surface area of each of the ball-bottom metal layers is greater than the bottom surface of the corresponding first opening. The present invention provides a flat top bump structure that is adapted to be disposed on a substrate. The substrate has a pad and a protective layer, wherein the protective layer has an opening 'which exposes the portion of the pad. The flat-top bump structure comprises a ball-bottom metal layer and a flat-top bump, wherein the ball-bottom metal layer is disposed on the protective layer and covers the pads exposed by the protective layer. The flat top bumps are disposed on the bottom metal layer above the pads, wherein the top surface of the flat top bumps is planar. Further, the bottom area of the flat bump is less than the bottom φ product of π, and the bottom surface of the metal layer of the ball is larger than the bottom area of the opening. In an embodiment of the invention, the material of the flat top bump may be gold. In an embodiment of the invention, the material of the pad may be aluminum. In one embodiment of the invention, the substrate can be a wafer or wafer. Based on the above, since the present invention forms a flat top bump in the opening of the protective layer', such flat top bump has a flat page. In addition, due to the ball 200834762 CN-9509003 22159twf.doc/n, the bottom surface area of the flat top metal layer is larger than the bottom area of the flat top bump, and the bump structure is less likely to produce an undercut effect. The above features and advantages of the present invention will become more apparent from the following detailed description. [Embodiment]
圖2A至圖2D為本發明之一實施例之一種平頂 結構的製造方法騎意圖。請先參相Μ，本實施例之 頂凸塊結構的製造方法包括下列步驟。首先，提供一基板 210 ’而基板210具有多個接墊22〇與一保護層23〇，& 保護層230具有多個第一開口 2施，且各第一開口驗 分別暴露出相對應之接墊2 2 〇之一部分。值得注意的是， 為了便於說明’本實施例的開口 23〇a與接墊22〇 ^僅洽示 一個。此外，此基板210可以是晶圓或是其他承载器，曰而 接墊220的材質可以是鋁、鋼或是其他金屬。 請繼續參考圖2A ’在基板21G上方形成—球底金屬 材料層310，以覆蓋保護層23〇與保護層23〇所暴露出之 接墊220。此外，形成球底金屬材料層31〇的方法可以是 濺鍍製程、物理氣相沈積製程或化學氣相沈積製程。然後， 在，底金屬材料層310上形成一第一圖案化光阻層=1〇， 且第一圖案化光阻層410具有多個第二開口 41〇a，其分別 暴露出保護層230所暴露出之接墊22〇上方之球底金屬材 料層310值传庄思的疋，第二開口 41 〇a小於接塾no以 及第一開口 230a。 8 200834762 CN-9509003 22159twf.doc/n 請參考圖2A與圖2B，在第二開口 4施~形成平頂 凸塊320。換言之’在保護層23〇所暴露出之接墊22〇上 方之球底金屬材料層31〇上形成多個平頂凸塊no。此外， 形成平頂凸塊320可以是電鏟製程。織，移除第一圖案 化光阻層410。值得注意的是，各平頂凸塊32〇的底面積 小於相對應之第-開口 230a的底面積，且平頂凸塊32〇 的頂面320a為平面。 _ 請參考圖2C，在球底金屬材料層310上形成一第二 圖案化光阻層42G，其中第二圖案化光阻層42()覆蓋這些 平頂凸塊320，並暴露出部分球底金屬材料層31〇。 、請參考圖2C與圖2D，以第二圖案化光阻層為遮 罩進行一蝕刻製程，移除部分球底金屬材料層31〇，以形 成球底金屬層312。此時，球底金屬層312的底面積大於 相對應之第一開口 230a的底面積。然後，移除第二圖案化 光阻層420。至此，大致完成本實施例之平頂凸塊結構的 製造流程。此外，在移除第二圖案化光阻層42〇之後，也 _ 可以對於基板210進行一切割製程，以形成多個晶片結構 (未緣示）。以下將就此平頂凸塊結構的細部結構進行說 明。 圖^3為本發明之一實施例之一種平頂凸塊結構的俯視 圖。請參考圖3與圖2D，此平頂凸塊結構適於配置於一基 板210上。此基板21〇具有一接墊22〇與一保護層23〇， 其中保護層230具有一第一開口 23〇a，其暴露出接墊22〇 之一部分。此外，基板210可以是晶片或晶圓。此平頂凸 200834762 CN-9509003 22159twf.doc/n 塊結構包括一球底金屬層312與一平頂凸塊320，其中球 底金屬層312配置於保護層230上，並覆蓋保護層230所 暴露出之接墊220。平頂凸塊320配置於接墊220上方之 球底金屬層312上，其中平頂凸塊32〇的頂面32〇a為平 面。此外，平頂凸塊302的底面積小於第一開口 23〇a的底 面積，且球底金屬層312的底面積大於第一開口 23〇a的底 面積（如圖3所示）。另外，平頂凸塊32〇的材質可以是 金。 由於平頂凸塊320形成於保護層230的第一開口 230a 内，且平頂凸塊302的底面積小於第一開口 23〇a的底面 積，因此此種平頂凸塊320具有平坦的頂面32〇a，以改善 驾知技術所具有的城牆效應。此外，由於球底金屬層312 的底面積大於平頂凸塊320的底面積，因此此種平頂凸塊 結構較不易產生底切效應。 雖然本發明已以較佳實施例揭露如上，然其並非用以 限定本發明，任何所屬技術領域中具有通常知識者，在不 脫離本發明之精神和範圍内，當可作些許之更動與潤飾， 因此本發明之保護範圍當視後附之申請專利範圍所界定者 為準。 【圖式簡單說明】 圖1A為習知的金凸塊的剖面圖。 圖1B為習知的金凸塊的俯視圖。 圖2A至圖2D為本發明之一實施例之一種平頂凸塊 200834762 CN-9509003 22159tw£doc/n 結構的製造方法的示意圖。 圖3為本發明之一實施例之一種平頂凸塊結構的俯視 圖0 【主要元件符號說明】 110 :晶片 120 :鋁接墊 _ 130 :保護層 130a :開口 140 :球底金屬層 150 :金凸塊 150a :環狀凸起部 210 :基板 220 :接墊 230 :保護層 230a :第一開口 ⑩ 310 :球底金屬材料層 312 :球底金屬層 320 :平頂凸塊 320a :頂面 410 :第一圖‘案化光阻層 410a :第二開口 420 :第二圖案化光阻層 112A to 2D are schematic views of a method of manufacturing a flat top structure according to an embodiment of the present invention. Please refer to the first step. The manufacturing method of the top bump structure of this embodiment includes the following steps. First, a substrate 210' is provided, and the substrate 210 has a plurality of pads 22 and a protective layer 23, and the protective layer 230 has a plurality of first openings 2, and each of the first openings is exposed to a corresponding one. One of the pads 2 2 〇. It is to be noted that, for convenience of explanation, the opening 23〇a of the present embodiment and the pad 22〇 are only shown one. In addition, the substrate 210 may be a wafer or other carrier, and the material of the pad 220 may be aluminum, steel or other metal. Referring to FIG. 2A', a ball-metal material layer 310 is formed over the substrate 21G to cover the pads 220 exposed by the protective layer 23 and the protective layer 23A. Further, the method of forming the ball-bottom metal material layer 31 may be a sputtering process, a physical vapor deposition process, or a chemical vapor deposition process. Then, a first patterned photoresist layer is formed on the bottom metal material layer 310, and the first patterned photoresist layer 410 has a plurality of second openings 41A, which respectively expose the protective layer 230. The layer of the bottom metal material 310 above the exposed pad 22 is transmitted by the entangled layer, and the second opening 41 〇a is smaller than the interface no and the first opening 230a. 8 200834762 CN-9509003 22159twf.doc/n Referring to FIG. 2A and FIG. 2B, a flat top bump 320 is formed in the second opening 4. In other words, a plurality of flat-top bumps no are formed on the ball-bottom metal material layer 31 of the pad 22 which is exposed by the protective layer 23A. Additionally, forming the flat top bump 320 can be a shovel process. The first patterned photoresist layer 410 is removed. It is to be noted that the bottom area of each flat top bump 32 is smaller than the bottom area of the corresponding first opening 230a, and the top surface 320a of the flat top bump 32 is flat. Referring to FIG. 2C, a second patterned photoresist layer 42G is formed on the ball-metal material layer 310, wherein the second patterned photoresist layer 42 covers the flat-top bumps 320 and exposes a portion of the ball bottom. The metal material layer 31 is. Referring to FIG. 2C and FIG. 2D, an etching process is performed by using the second patterned photoresist layer as a mask, and a portion of the bottom metal material layer 31 is removed to form a ball-bottom metal layer 312. At this time, the bottom area of the bottom metal layer 312 is larger than the bottom area of the corresponding first opening 230a. Then, the second patterned photoresist layer 420 is removed. So far, the manufacturing process of the flat top bump structure of this embodiment has been substantially completed. In addition, after the second patterned photoresist layer 42 is removed, a cutting process may be performed on the substrate 210 to form a plurality of wafer structures (not shown). The detailed structure of the flat-top bump structure will be described below. Figure 3 is a top plan view of a flat top bump structure in accordance with one embodiment of the present invention. Referring to FIG. 3 and FIG. 2D, the flat top bump structure is adapted to be disposed on a substrate 210. The substrate 21A has a pad 22 and a protective layer 23A, wherein the protective layer 230 has a first opening 23〇a that exposes a portion of the pad 22〇. Further, the substrate 210 may be a wafer or a wafer. The flat top bump 200834762 CN-9509003 22159 twf.doc/n block structure includes a ball bottom metal layer 312 and a flat top bump 320, wherein the ball bottom metal layer 312 is disposed on the protective layer 230 and covered by the protective layer 230. The pad 220. The flat top bump 320 is disposed on the bottom metal layer 312 above the pad 220, wherein the top surface 32〇a of the flat top bump 32 is flat. In addition, the bottom area of the flat top bump 302 is smaller than the bottom area of the first opening 23〇a, and the bottom area of the bottom metal layer 312 is larger than the bottom area of the first opening 23〇a (as shown in FIG. 3). In addition, the material of the flat top bump 32〇 may be gold. Since the flat top bump 320 is formed in the first opening 230a of the protective layer 230, and the bottom area of the flat top bump 302 is smaller than the bottom area of the first opening 23〇a, the flat top bump 320 has a flat top. Face 32〇a to improve the wall effect of driving technology. In addition, since the bottom area of the ball bottom metal layer 312 is larger than the bottom area of the flat top bump 320, such a flat top bump structure is less likely to cause an undercut effect. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a cross-sectional view of a conventional gold bump. FIG. 1B is a top view of a conventional gold bump. 2A to 2D are schematic views showing a manufacturing method of a flat top bump 200834762 CN-9509003 22159 tw doc/n structure according to an embodiment of the present invention. 3 is a plan view of a flat-top bump structure according to an embodiment of the present invention. [Main component symbol description] 110: Wafer 120: Aluminum pad _130: Protective layer 130a: Opening 140: Bottom metal layer 150: Gold Bump 150a: annular boss 210: substrate 220: pad 230: protective layer 230a: first opening 10 310: ball metal material layer 312: ball bottom metal layer 320: flat top bump 320a: top surface 410 The first figure 'cased photoresist layer 410a: second opening 420: second patterned photoresist layer 11