201128719 六、發明說明： 【發明所屬之技術領域】 本發明係有關一種鐵粉錫基複合銲錫合金球及其覆晶植 球之方法，主要為一種應用於覆晶構裝之技術，藉由含有:粉 的銲錫合金球，植球於電路基板上，進行最有效的銲接功能者。 【先前技術】 曰近年來電子構裝技術，受到上游晶片設計、製造能力不斷 提升，產出尚密度、高I/O數、高速度及高功率等相 件的衝擊；以及下游消費者對3C電子產品輕、薄、短、小的 殷切需求’兩面絲下，迫使電子構裝業者，f要不斷的推陳 發展新技術，達到減小體積、增加良率、提高散熱效果、降低 成本及強化可靠度等’才能符合市場需求。針對高密度封裝， 覆晶方式已成為最重要的連線方法。由於銲錫具備自我對位及 可重工的特性，因此覆晶凸塊大多使用銲錫材料，其技術關鍵 f於鋅錫凸塊的製似組裝’傳統賴凸塊的製作方法主要可 分為電鍵及錫膏鋼板印刷兩種，電鍵法除了環保問題最大的 發展障礙在於電雜定觸合金組成的_性，尤其因應歐盟 要求銲錫需採用無錯成份，其鑛液配方、電錄參數及穩定性均 不易掌握，且必須耗f_的光罩成本，無法滿足市場普及性 求，所以近年來大部分封裝業者針對覆晶組裝均 逐漸採用錫膏鋼板印刷製程，然而當覆晶凸塊尺寸被要求至 0· 1刪以下時，即使是採用直徑的錫粉其單點銲錫凸 塊也，由》數幾顆錫粉所構成，迴銲後勢必造成因銲點大小 不-所衍伸的晶片共平面度不佳的問題，而若要製作更小的鎖 201128719 粉’則包括喷粉、氧化、粒徑篩選及粉塵污染等問題均很難克 服；另一方面’以錫膏製作覆晶凸塊製程，經常會有助銲劑迴 銲後在銲錫内部產生孔洞的現象，這些因素使得以錫膏鋼板印 刷技術生產覆晶凸塊，面臨嚴峻挑戰。因此，為解決錫膏在細 間距(0. lmm以下）製程能力不足的缺點，最新的發展趨勢是直 接使用超微小銲錫合金球(〇. 1刪以下），進行植球、迴銲形成 覆晶銲錫凸塊。但在超微小錫球的植球製程中，如何克服錫球 表面吸濕及靜電力的影響，而能精準操控錫球置於正確位置， 將面臨極大挑戰，目前尚無相關的技術足以有效的完成。 【發明内容】 本發明為一種鐵粉錫基複合銲錫合金球及其覆晶植球之 方法，主要係利用將極小的鐡金屬顆粒添加在銲錫球内，以製 造出含有鐵粉的銲錫合金球’而可利用磁鐵有效將整顆複合銲 錫合金球吸引’利用此一特性，當可有效協助超微小銲錫合金 球定位，而牢固的被吸引、充填在植球鋼板孔洞内，配合適當 的真空除球製程’吸去多餘銲錫合金球，便可抵抗超微小銲錫 合金球之表面吸濕、靜電效應所產生的團簇集結現象，而能順 利完成植球製程。即本發明之目的在於製作出含有鐵粉的銲錫 合金球’並利用其使用在覆晶植球製程上，以達到增進覆晶之 有效性並簡化程序’且使結合後電路基板和構件的結合強度增 加’而具有顯著之進步性及創新性者。 【實施方式】 本發明主要包括二階段的技術特徵，其一為將鐵粉混合 於#錫合金球内，形成一複合鮮錫合金球的組合結構，以提 昇電路基板與電子元件之結合強度，再將以銲錫合金球應用 於覆晶植球的技術，同時兼具簡化製程之功效者。 4 201128719 _鐵祕基之複合銲錫合金球的製造方式 ，由於鐵在 銲齡的溶解度與擴散能力域，因此不會餘化之虞，根 據文獻可知鐵的添加可有效提高銲錫的常溫抗拉強度，尤其 在抵抗高，潛變之能力表現上更是㈣，約可比無強化相顆 粒之録錫向出五倍之多。為了提高鐵與銲錫的潤濕性，本發 明之-較佳實施方式係在鐵粉表面上先鑛一層锡，使其表面 可形成FeSn2金屬間化合物，製程雖較為繁琐，但較易使鐵 粉^與錫溶湯融合在-起；而為了均句散佈，更應用到磁場 • 的$哀境作用。另外’本發明可採用化學鑛的方法，其主要原 因為’化學鑛不f額外供應電流，沒有電流斷路或分佈不均 的問題，因此鍍層較為均勻且平坦，而利用舰中的還原劑 將錫離子還原_在輸的表面，但此表面必須_化錄锡 反應進行’附著第-層金屬錫後，此錫層又繼續催化下一層 錫的還原沉積，故化學鍍錫亦稱自身催化齡ut⑽购他 Plating)。另外，本發明在製備鐵顆粒強化無鉛複合銲錫是 以Sn3AgO· 5Cu錫條與表面預鍍好錫的麵粒配置成複合鲜錫 鲁合金錫條，製作成不同比例鐵顆粒含量的複合銲錫，來達成 改善銲錫熱機強度的目的。 在製程上，首先將鐵粉表面鍍上一層化學錫（chemicM plating) ’化學錫是指於水溶液中之金屬離子被在控制之環 境下，予以化學還原，而不需藉電就能將锡金屬鍍在鐵粉上， 其鍍層是連續的，且自身具有催化性(aut〇catalytic)。化學 鍍液配方需具備的特性包括：還原劑的氧化還原電位必須足 以還原金屬離子，使金屬析出；鍍浴需安定，在未使用時需 不起作用，只有在催化性的鍍件表面接觸時才迅速開始作用 析出金屬鍍層；析出速率要能被控制、pH值，溫度能調節 201128719 析出速率；析出的金屬須具有催化作用，以進行自身催化電 鍍，鍍層才能連續形成，以達到所需之錢層厚度；鍍液反應 生成物須不妨礙鍍液的功能，鑛液的壽命才能長久。 進行化學鍍錫製程前，本發明之一實施例係先以脫脂劑 清潔鐵粉，脫脂劑為一酸性及界面活性劑混合液體，操作溫 度為5〇t，浸泡時間為}分鐘，之後再以去離子水清洗。接 著再以微银液將鐵顆粒表面粗糙化，以提升錫面之附著力， 微餘時間為5秒鐘。為了讓防止化錫主槽液受到污染或稀 釋，因此在室溫下，先於化學鍍錫液中預浸1分鐘，以避免 鐵粉直接與主槽液反應，而能維持浸錫液之酸當量與錫當 量。化錫以置換反應鍍在鐵粉表面上。之後，將化鍍完成的 試片浸泡於乙醇清洗2分鐘，再以80°c的熱水清洗2〜3 -人，將殘留於試片中的化錫液徹底洗淨，最後將鐵粉供乾。 鐵粉完成鍍錫後，再與熔融Sn3Ag〇. 5Cu錫湯均勻混合，以熔 煉完成複合觸合金球，即依本發明製輯完成的銲錫合金 球係含有鐵的成分於其内部者。 另有關在0· 1mm以下的超微細錫球的植球技術方面，目前 已知的方關細印助銲織，再使用特殊技術將微小錫 球填入鋼板孔_，完成迴銲植球㈣，而在晶圓上，製作出 錫球：8G’/間距:⑽—之高密度接點；或是侧精密度高 的超微小管路傳輸銲錫球，當錫球到達出口的銲墊位置後，施 予雷射光束迅速加熱轉，使其糊縣在⑼㈣上。但針 對超微細錫球在植球製程時遭遇到最嚴重的問題在於錫球微 小化之後所衍生絲㈣濕、靜電效應所產生的團簇集結現 象，因此微轉賴㈣彳驗找將是麟製程技術發展的重 要關鍵，喊述e知方式均_財雜制。為了克服超微小 201128719 锡球的植球困難問題’本發明採用具備前述備受磁性的鐵金屬 顆粒複合銲錫合金球，請參閱圖一所示，本發明的覆晶植球方 式如下，主要係在植球過程中，於基板（1)底部設以磁性構件 (2) ’藉由其磁性有效可吸住銲錫合金球(3)，使銲錫合金球(3) 落入鋼板(4)的細微孔洞（41)内，且係位在基板（丨）的銲墊（1 j) 上方，而後再以真空除球設備（5)或刮板(6)，除去鋼板(4)表 面多餘的知錫合金球(3)，即可完成覆晶植球的製程，在此過 程中，由於受到磁性的吸力作用，故能有效的抵抗超微小銲錫 合金球(3)因表面吸濕、靜電效應所產生的團簇集結現象，而 能順利植球於基板（1)上，以提供後續的銲接工作，而能完成 整個後續製程者。 藉由上述覆晶植球所完成的電路基板，其各組件的結合強 度’經由衝擊可靠度試驗’採加載質量反覆進行不同高度及方 向的掉落衝_試’測驗絲顯示，依本發明製程所完成產品 之録接強度賴於f知㈣凸塊的產品，是知，本發明之技術 顯已具備實舰步性，並可提做業上的_舰，即本發明 確已符合發明專利之要件者。 【圖式簡單說明】 圖一為本發明覆晶植球方式之示意圖 【主要元件符號說明】 (1)基板（11鹏⑵磁性構件⑶銲錫合金球 ⑷鋼板（41)細微孔洞⑸真空除球設備⑹到板201128719 VI. Description of the Invention: [Technical Field] The present invention relates to an iron powder tin-based composite solder alloy ball and a method for coating the same, which is mainly a technique applied to a flip chip structure, by containing : Powdered solder alloy balls, which are implanted on a circuit board to perform the most effective soldering function. [Prior Art] In recent years, the electronic assembly technology has been continuously upgraded by upstream chip design and manufacturing capabilities, and the impact of output density, high I/O number, high speed and high power phase parts; and downstream consumers' 3C The light, thin, short and small eager demand for electronic products is under the influence of two sides, forcing the electronic assembly industry to constantly develop new technologies to reduce volume, increase yield, improve heat dissipation, reduce costs and strengthen Reliability, etc. can meet market demand. For high-density packaging, flip chip has become the most important method of wiring. Because solder has self-alignment and reworkability, most of the flip-chip bumps use solder materials. The key to the technology is the assembly of zinc-tin bumps. The traditional methods of making bumps can be divided into electric keys and tin. There are two kinds of paste steel plate printing. In addition to the environmental protection problem, the biggest development obstacle of the electric key method lies in the composition of the electric alloy. In particular, in response to the requirements of the EU, the solder needs to use the error-free component, and its mineral liquid formula, electro-recording parameters and stability are not easy. Mastering, and must consume f_ reticle cost, can not meet the market popularity, so in recent years, most of the packaging industry for the flip chip assembly are gradually using the solder paste steel printing process, however, when the size of the flip chip is required to 0 · 1 When deleting the following, even a single-point solder bump with a diameter of tin powder is composed of several tin powders. After reflow, it is bound to cause the wafer coplanarity due to the size of the solder joint. Poor problems, and if you want to make a smaller lock 201128719 powder, it will be difficult to overcome problems such as dusting, oxidation, particle size screening and dust pollution; Bumping process, there is often a flux phenomenon voids inside the solder after reflow, these factors make the steel sheet to print paste bump flip chip technology to produce, it faces serious challenges. Therefore, in order to solve the shortcomings of the solder paste in the fine pitch (less than 0.1 mm) process, the latest development trend is to directly use the ultra-small solder alloy ball (〇. 1 delete below) to carry out the ball-forming and re-welding. Solder solder bumps. However, in the ball-forming process of ultra-tin solder balls, how to overcome the influence of the surface moisture absorption and electrostatic force of the solder ball, and accurately control the solder ball in the correct position, will face great challenges, and there is no relevant technology at present. The completion. SUMMARY OF THE INVENTION The present invention is an iron powder tin-based composite solder alloy ball and a method for coating the same, mainly by adding a small amount of base metal particles to a solder ball to produce a solder alloy ball containing iron powder. 'And the magnet can effectively attract the entire composite solder alloy ball'. Using this feature, when it can effectively assist the positioning of the ultra-small solder alloy ball, it is firmly attracted and filled in the hole of the ball plated steel, with appropriate vacuum. In addition to the ball process 'absorbs the excess solder alloy ball, it can resist the clustering phenomenon caused by the surface moisture absorption and electrostatic effect of the ultra-small solder alloy ball, and can successfully complete the ball-planting process. That is, the object of the present invention is to produce a solder alloy ball containing iron powder and use it in a flip chip balling process to achieve the effectiveness of the flip chip and simplify the procedure' and to combine the combined circuit substrate and the component. Increased strength' with significant advancement and innovation. [Embodiment] The present invention mainly includes two-stage technical features, one of which is to mix iron powder in a #tin alloy ball to form a composite structure of a composite fresh tin alloy ball to improve the bonding strength between the circuit substrate and the electronic component. The solder alloy ball will be applied to the technique of flip-chip ball-planting, and at the same time, it will have the effect of simplifying the process. 4 201128719 _Iron-based composite solder alloy ball manufacturing method, due to the solubility of iron in the welding age and diffusion capacity, so there is no residual entanglement, according to the literature, the addition of iron can effectively improve the normal temperature tensile strength of solder In particular, in the resistance to high, the ability to change the potential is (4), about five times more than the recording of non-reinforced phase particles. In order to improve the wettability of iron and solder, the preferred embodiment of the present invention is to deposit a layer of tin on the surface of the iron powder to form a FeSn2 intermetallic compound on the surface, which is cumbersome in process, but is easy to make iron powder. ^Incorporating with tin-dissolving soup; and in order to spread evenly, it is applied to the magnetic field's grief effect. In addition, the invention can adopt the method of chemical ore, the main reason is that 'the chemical mine does not supply additional current, there is no problem of current interruption or uneven distribution, so the coating is relatively uniform and flat, and the tin is reduced by using the reducing agent in the ship. Ion reduction _ on the surface of the transfer, but this surface must be _chemically tinned to carry out 'attachment of the first layer of tin metal, the tin layer continues to catalyze the reduction deposition of the next layer of tin, so the chemical tin plating is also known as its own catalytic age ut (10) Buy him Plating). In addition, in the preparation of the iron particle-reinforced lead-free composite solder, the Sn3AgO·5Cu tin strip and the surface pre-plated tin surface are arranged to form a composite tin-tin alloy tin bar, and a composite solder having different proportions of iron particles is prepared. Achieve the purpose of improving the strength of the soldering heat machine. In the process, the surface of the iron powder is first coated with a layer of chemical tin (chemicM plating). Chemical tin means that the metal ions in the aqueous solution are chemically reduced under controlled conditions, and the tin metal can be removed without using electricity. Plated on iron powder, the coating is continuous and self-catalytic (aut〇catalytic). The characteristics of the electroless plating solution include: the redox potential of the reducing agent must be sufficient to reduce the metal ions and precipitate the metal; the plating bath needs to be stabilized, and it does not function when not in use, only when the surface of the catalytic plating is in contact. It is necessary to quickly start to precipitate the metal coating; the precipitation rate should be controlled, the pH value, and the temperature can adjust the precipitation rate of 201128719; the precipitated metal must have a catalytic effect for self-catalytic plating, and the coating can be continuously formed to achieve the required money. The thickness of the layer; the reaction product of the plating solution must not interfere with the function of the plating solution, and the life of the mineral liquid can last for a long time. Before performing the electroless tin plating process, an embodiment of the present invention first cleans the iron powder with a degreasing agent, and the degreasing agent is an acidic and surfactant mixed liquid, the operating temperature is 5 〇t, the immersion time is _minute, and then Wash with deionized water. The surface of the iron particles is then roughened with a microsilver solution to enhance the adhesion of the tin surface for a period of 5 seconds. In order to prevent the main bath solution from being contaminated or diluted, pre-dip for 1 minute at the room temperature in the electroless tin plating solution to avoid the iron powder directly reacting with the main bath liquid, and to maintain the acidity of the tin immersion liquid. Equivalent to tin equivalent. The tin is plated on the surface of the iron powder by a displacement reaction. After that, the test piece after the plating is immersed in ethanol for 2 minutes, and then washed with hot water of 80 ° C for 2 to 3 -, and the tin solution remaining in the test piece is thoroughly washed, and finally the iron powder is supplied. dry. After the iron powder is tinned, it is uniformly mixed with the molten Sn3Ag〇5Cu tin soup to melt the composite contact alloy ball, that is, the solder alloy ball system prepared according to the present invention contains iron component inside. In addition, regarding the ball-forming technology of ultra-fine solder balls below 0·1mm, the currently known fine-welded soldering and weaving, and then using special technology to fill the tiny tin balls into the steel plate hole _, complete the reflow ball (4) On the wafer, a solder ball is produced: 8G'/pitch: (10) - a high-density contact; or a super-fine pipeline with a high degree of precision transmits the solder ball, when the solder ball reaches the exit pad position The laser beam is applied to heat rapidly and the paste is placed on (9) (four). However, the most serious problem encountered in the process of planting the ultrafine solder balls is the clustering phenomenon caused by the wet and electrostatic effects of the filaments (4) after the tin ball is miniaturized. Therefore, the micro-transfer (4) inspection will be a lining. The key to the development of process technology is to call the e-information method. In order to overcome the problem of the ball-forming difficulty of the ultra-small 201128719 solder ball, the present invention adopts the iron-metal particle composite solder alloy ball with the above-mentioned magnetic properties. Referring to FIG. 1 , the flip-chip balling method of the present invention is as follows, mainly During the ball placement process, the magnetic member (2) is disposed at the bottom of the substrate (1). By virtue of its magnetic efficiency, the solder alloy ball (3) can be sucked, and the solder alloy ball (3) falls into the fineness of the steel plate (4). Inside the hole (41), and the position is above the pad (1 j) of the substrate (丨), and then the vacuum ball removing device (5) or the scraper (6) is used to remove the excess tin of the surface of the steel plate (4). The alloy ball (3) can complete the process of flip chip balling. In this process, due to the magnetic suction force, it can effectively resist the ultra-small solder alloy ball. (3) Due to surface moisture absorption and electrostatic effect The generated clusters are aggregated, and the balls can be smoothly implanted on the substrate (1) to provide subsequent welding work, and the entire subsequent process can be completed. The circuit board completed by the above-mentioned flip chip ball bonding, the bonding strength of each component 'through the impact reliability test', the loading quality is repeated, and the falling and punching of different heights and directions are performed, the test wire is displayed, according to the process of the invention The strength of the recording of the finished product depends on the product of the (four) bumps. It is known that the technology of the present invention has the actual shipstep and can be used as the industry ship, that is, the invention has indeed met the invention patent. The person in need. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a flip chip balling method according to the present invention. [Main component symbol description] (1) Substrate (11 Peng (2) magnetic member (3) Solder alloy ball (4) Steel plate (41) Fine hole (5) Vacuum ball removing device (6) to the board