TWI783149B - Cu nuclei, solder joints, solder paste and foam solder - Google Patents
Cu nuclei, solder joints, solder paste and foam solder Download PDFInfo
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Abstract
本發明之課題係提供一種實現高真球度及低硬度且能夠抑制變色之使用金屬層被覆Cu球而成之Cu核球。 本發明之解決手段，係提供一種Cu核球11A，其具備Cu球1、及將Cu球1的表面被覆之焊料層3，該Cu球1係Fe、Ag及Ni之中至少1種的含量之合計為5.0質量ppm以上且50.0質量ppm以下，S的含量為0質量ppm以上且1.0質量ppm以下，P的含量為0質量ppm以上且小於3.0質量ppm，剩餘部分為Cu及其它不純物元素，Cu球1的純度為99.995質量%以上且99.9995質量%以下，真球度為0.95以上，焊料層係含有Sn及Cu之(Sn-Cu)系焊料合金。The object of the present invention is to provide a Cu core ball that uses a metal layer to coat the Cu ball, which realizes high sphericity and low hardness and can suppress discoloration. The solution of the present invention is to provide a Cu core ball 11A, which includes a Cu ball 1 and a solder layer 3 covering the surface of the Cu ball 1, and the content of the Cu ball 1 is at least one of Fe, Ag, and Ni. The total is 5.0 mass ppm to 50.0 mass ppm, the S content is 0 mass ppm to 1.0 mass ppm, the P content is 0 mass ppm to less than 3.0 mass ppm, and the rest is Cu and other impurity elements, The purity of the Cu ball 1 is not less than 99.995% by mass and not more than 99.9995% by mass, the true sphericity is not less than 0.95, and the solder layer is a (Sn—Cu)-based solder alloy containing Sn and Cu.
Description
本發明係有關於一種使用金屬層被覆Cu球而成之Cu核球、及使用該Cu核球之焊接頭、焊膏及泡沫焊料。The present invention relates to a Cu core ball formed by coating Cu balls with a metal layer, and a welding head, solder paste and foam solder using the Cu core ball.
近年來，由於小型資訊機器發達，所搭載的電子零件係進行急速的小型化。由於小型化的要求，電子零件係為了因應連接端子的狹小化和封裝面積的縮小化，而應用在背面設置有電極之球格柵陣列(以下稱為「BGA」)。In recent years, due to the development of small information devices, the electronic components mounted therein have undergone rapid miniaturization. Due to the requirement of miniaturization, electronic components are applied to Ball Grid Array (hereinafter referred to as "BGA") with electrodes arranged on the back side in response to the miniaturization of connection terminals and miniaturization of packaging area.
應用BGA之電子零件係例如半導體組件。在半導體組件係使用樹脂將具有電極之半導體晶片密封。半導體晶片的電極係形成有焊料凸塊(solder bump)。該焊料凸塊係藉由將焊球接合在半導體晶片的電極而形成。應用BGA之半導體組件係藉由將經加熱而熔融的焊料凸塊與印刷基板的導電性墊(land)接合而搭載在印刷基板。又，為了因應進一步高密度封裝的要求，正研討在高度方向堆積半導體組件而成之三維高密度封裝。Electronic components using BGA are semiconductor components, for example. In semiconductor components, resin is used to seal semiconductor wafers with electrodes. The electrodes of the semiconductor wafer are formed with solder bumps. The solder bumps are formed by bonding solder balls to electrodes of a semiconductor chip. A semiconductor device to which BGA is applied is mounted on a printed board by bonding heated and melted solder bumps to conductive lands of the printed board. Also, in order to meet the demand for further high-density packaging, three-dimensional high-density packaging in which semiconductor elements are stacked in the height direction is being studied.
電子零件的高密度封裝係有因α線進入半導體集積電路(IC)的記憶胞(memory cell)中而引起將記憶內容重寫的軟錯誤(soft error)之情形。因此，近年係進行減低放射性同位元素的含量之低α線的焊接材料和Cu球之開發。專利文獻1係揭示一種含有Pb、Bi，純度為99.9%以上且99.995%以下之低α線量的Cu球。專利文獻2係揭示一種能夠實現純度為99.9%以上且99.995%以下、真球度為0.95以上、維氏硬度為20HV以上且60HV以下之Cu球。In the high-density packaging of electronic components, α-rays enter the memory cells of semiconductor integrated circuits (ICs), causing soft errors in which memory content is rewritten. Therefore, in recent years, the development of low-α-ray soldering materials and Cu balls that reduce the content of radioactive isotopes has been carried out.
但是Cu球之結晶粒為較微細時，因為維氏硬度變大，所以對於來自外部的應力之耐久性變低且耐落下衝擊性變差。因此，在電子零件的封裝所使用的Cu球係被要求預定柔軟性亦即預定值以下的維氏硬度。However, when the crystal grains of the Cu balls are finer, the Vickers hardness becomes larger, so the durability against external stress becomes lower, and the drop impact resistance deteriorates. Therefore, the Cu ball system used in the packaging of electronic components is required to have predetermined flexibility, that is, a Vickers hardness equal to or less than a predetermined value.
為了製造柔軟的Cu球，慣例是提升Cu的純度。這是因為不純物元素係作為Cu球中的結晶核之功能，所以不純物元素較少時，結晶粒較大地成長，其結果，Cu球的維氏硬度變小之緣故。但是提升Cu球的純度時，Cu球的真球度為變低。In order to make soft Cu balls, it is common practice to increase the purity of Cu. This is because the impurity elements function as crystal nuclei in the Cu balls, so when there are fewer impurity elements, the crystal grains grow larger, and as a result, the Vickers hardness of the Cu balls becomes smaller. However, when the purity of the Cu ball is increased, the true sphericity of the Cu ball becomes lower.
Cu球的真球度較低時，將Cu球封裝在電極上時，有無法確保自對準性之可能性，同時在半導體晶片的封裝時Cu球的高度變為不均勻且有引起接合不良之情形。When the true sphericity of the Cu ball is low, the self-alignment may not be ensured when the Cu ball is packaged on the electrode. At the same time, the height of the Cu ball becomes uneven during the packaging of the semiconductor chip, which may cause bonding failure. situation.
專利文獻3係揭示一種Cu的質量比率為大於99.995%、P與S的質量比率之合計為3ppm以上且30ppm以下且具有適當的真球度和維氏硬度之Cu球。
又，經三維高密度封裝之半導體組件為BGA，將焊球載置在半導體晶片的電極上而進行回流處理時，因半導體組件的自重而有焊球塌陷掉之情形。產生此種之情形時焊料從電極擠出，而且有電極間彼此接觸且電極間產生短路之可能性。In addition, the three-dimensional high-density packaged semiconductor component is BGA. When solder balls are placed on the electrodes of the semiconductor chip and reflowed, the solder balls may collapse due to the weight of the semiconductor component. When such a situation occurs, the solder is extruded from the electrodes, and there is a possibility that the electrodes are in contact with each other and a short circuit occurs between the electrodes.
為了防止此種短路事故，有提案揭示一種不會因自重而塌陷、或焊料熔融時產生變形之焊料凸塊。具體而言，係將由金屬等所成型的球使用作為核，而且使用焊料被覆該核而成的核材料作為焊料凸塊。 [先前技術文獻] [專利文獻]In order to prevent such short-circuit accidents, there is a proposal to disclose a solder bump that does not collapse due to its own weight or deform when solder is melted. Specifically, a ball formed of metal or the like is used as a core, and a core material obtained by coating the core with solder is used as a solder bump. [Prior Art Literature] [Patent Document]
[專利文獻1] 日本特許第5435182號公報 [專利文獻2] 日本特許第5585751號公報 [專利文獻3] 日本特許第6256616號公報[Patent Document 1] Japanese Patent No. 5435182 [Patent Document 2] Japanese Patent No. 5585751 [Patent Document 3] Japanese Patent No. 6256616
但是新了解含有預定量以上的S之Cu球，係有在加熱時形成硫化物和硫氧化物而容易變色之問題。在Cu球之變色係成為濕潤性變差的原因，濕潤性變差係產生不濕潤和引起自對準性劣化。如此，容易變色的Cu球之Cu球表面與金屬層的密著性低落、金屬層表面的氧化和反應性變高等之緣故，而不適合使用金屬層之被覆。另一方面，Cu球的真球度較低時，使用金屬層被覆Cu球而成之Cu核球的真球度亦變低。However, it is newly known that Cu balls containing more than a predetermined amount of S tend to be discolored by forming sulfides and sulfur oxides when heated. The discoloration of the Cu balls causes poor wettability, and the poor wettability causes non-wetting and deterioration of self-alignment. In this way, Cu balls that are prone to discoloration are not suitable for coating with a metal layer because the adhesion between the Cu ball surface and the metal layer decreases, and the oxidation and reactivity of the metal layer surface become high. On the other hand, when the true sphericity of the Cu ball is low, the true sphericity of the Cu core ball formed by coating the Cu ball with the metal layer also becomes low.
因此，本發明之目的，係提供一種實現高真球度及低硬度且使用能夠抑制變色之Cu球而成之Cu核球、及使用該Cu核球之焊接頭、焊膏及泡沫焊料。Therefore, the object of the present invention is to provide a Cu core ball that realizes high true sphericity and low hardness and uses Cu balls that can suppress discoloration, and a soldering head, solder paste, and foamed solder using the Cu core ball.
本發明係如以下。 (1)一種Cu核球，係具備Cu球、及將Cu球的表面被覆之焊料層，該Cu球係Fe、Ag及Ni之中至少1種的含量之合計為5.0質量ppm以上且50.0質量ppm以下，S的含量為0質量ppm以上且1.0質量ppm以下，P的含量為0質量ppm以上且小於3.0質量ppm，剩餘部分為Cu及其它不純物元素，Cu球的純度為99.995質量%以上且99.9995質量%以下，真球度為0.95以上，焊料層係含有Sn及Cu之(Sn-Cu)系焊料合金。 (2)如上述(1)所述之Cu核球，其中焊料層係Cu的含量為大於0質量%且3.0質量%以下，Sn為剩餘部分。 (3)如上述(1)或(2)所述之Cu核球，其中焊料層係由含有Sn及0.1~3.0質量%的Cu之(Sn-Cu)系焊料合金所構成，將在焊料層中所含有的Cu之濃度比率(%)設為濃度比率(%)=(計量值(質量%)/目標含量(質量%))×100、或濃度比率(%)=(計量值的平均值(質量%)/目標含量(質量%))×100而表示時，濃度比率為70.0~130.0%的範圍內。 (4)如上述(1)或(2)所述之Cu核球，其中焊料層係由含有Sn及0.1~3.0質量%的Cu之(Sn-Cu)系焊料合金所構成，將在焊料層中所含有的Cu之濃度比率(%)設為濃度比率(%)=(計量值(質量%)/目標含量(質量%))×100、或濃度比率(%)=(計量值的平均值(質量%)/目標含量(質量%))×100而表示時，濃度比率為90.0~110.0%的範圍內。 (5)如上述(1)或(2)所述之Cu核球，其中焊料層係由含有Sn及Cu之(Sn-0.7Cu)系焊料合金所構成，將在焊料層中所含有的Cu之濃度比率(%)設為濃度比率(%)=(計量值(質量%)/目標含量(質量%))×100、或濃度比率(%)=(計量值的平均值(質量%)/目標含量(質量%))×100而表示時，濃度比率為72.9~97.1%的範圍內。 (6)如上述(1)或(2)所述之Cu核球，其中焊料層係由含有Sn及Cu之(Sn-3.0Cu)系焊料合金所構成，將在焊料層中所含有的Cu之濃度比率(%)設為濃度比率(%)=(計量值(質量%)/目標含量(質量%))×100、或濃度比率(%)=(計量值的平均值(質量%)/目標含量(質量%))×100而表示時，濃度比率為81.7~108.7%的範圍內。 (7)如上述(1)至(6)項中任一項所述之Cu核球，其中真球度為0.98以上。 (8)如上述(1)至(6)項中任一項所述之Cu核球，其中真球度為0.99以上。 (9)如上述(1)至(8)項中任一項所述之Cu核球，其中α線量為0.0200cph/cm2 以下。 (10)如上述(1)至(8)項中任一項所述之Cu核球，其中α線量為0.0010cph/cm2 以下。 (11)如上述(1)至(10)項中任一項所述之Cu核球，其中具備將Cu球表面被覆之金屬層，而且使用焊料層被覆金屬層表面且真球度為0.95以上。 The present invention is as follows. (1) A Cu core ball comprising a Cu ball and a solder layer covering the surface of the Cu ball, wherein the total content of at least one of Fe, Ag, and Ni in the Cu ball is 5.0 mass ppm or more and 50.0 mass ppm ppm or less, the S content is not less than 0 mass ppm and not more than 1.0 mass ppm, the P content is not less than 0 mass ppm and less than 3.0 mass ppm, the remainder is Cu and other impurity elements, and the purity of Cu balls is not less than 99.995 mass % and 99.9995 mass % or less, true sphericity of 0.95 or more, and the solder layer is a (Sn-Cu) based solder alloy containing Sn and Cu. (2) The Cu core ball as described in (1) above, wherein the content of Cu in the solder layer system is more than 0% by mass and not more than 3.0% by mass, and Sn is the remainder. (3) The Cu core ball as described in the above (1) or (2), wherein the solder layer is composed of a (Sn-Cu) based solder alloy containing Sn and 0.1 to 3.0% by mass of Cu, and the solder layer will Concentration ratio (%) of Cu contained in is set as concentration ratio (%)=(measured value (mass %)/target content (mass %))×100, or concentration ratio (%)=(average value of measured value When expressed as (mass %)/target content (mass %))×100, the concentration ratio is within the range of 70.0 to 130.0%. (4) The Cu core ball as described in the above (1) or (2), wherein the solder layer is composed of a (Sn-Cu) based solder alloy containing Sn and 0.1 to 3.0% by mass of Cu, and the solder layer will Concentration ratio (%) of Cu contained in is set as concentration ratio (%)=(measured value (mass %)/target content (mass %))×100, or concentration ratio (%)=(average value of measured value When expressed as (mass %)/target content (mass %))×100, the concentration ratio is within the range of 90.0 to 110.0%. (5) The Cu core ball as described in the above (1) or (2), wherein the solder layer is composed of a (Sn-0.7Cu)-based solder alloy containing Sn and Cu, and the Cu contained in the solder layer is The concentration ratio (%) is set as concentration ratio (%)=(measured value (mass%)/target content (mass%))×100, or concentration ratio (%)=(average value of measured value (mass%)/ When expressed as target content (mass %))×100, the concentration ratio is within the range of 72.9 to 97.1%. (6) The Cu core ball as described in the above (1) or (2), wherein the solder layer is composed of a (Sn-3.0Cu) based solder alloy containing Sn and Cu, and the Cu contained in the solder layer is The concentration ratio (%) is set as concentration ratio (%)=(measured value (mass%)/target content (mass%))×100, or concentration ratio (%)=(average value of measured value (mass%)/ When expressed as target content (mass %))×100, the concentration ratio is within the range of 81.7 to 108.7%. (7) The Cu core sphere described in any one of the above items (1) to (6), wherein the sphericity is 0.98 or more. (8) The Cu core sphere described in any one of the above items (1) to (6), wherein the sphericity is 0.99 or more. (9) The Cu core sphere described in any one of the above items (1) to (8), wherein the amount of α rays is 0.0200 cph/cm 2 or less. (10) The Cu core sphere described in any one of the above items (1) to (8), wherein the amount of α rays is 0.0010 cph/cm 2 or less. (11) The Cu core ball described in any one of the above items (1) to (10), which has a metal layer covering the surface of the Cu ball, and the surface of the metal layer is covered with a solder layer, and the true sphericity is 0.95 or more .
(12)如上述(11)所述之Cu核球，其中真球度為0.98以上。 (12) The Cu core sphere described in (11) above, wherein the sphericity is 0.98 or more.
(13)如上述(11)所述之Cu核球，其中真球度為0.99以上。 (13) The Cu core sphere described in (11) above, wherein the sphericity is 0.99 or more.
(14)如上述(11)至(13)項中任一項所述之Cu核球，其中α線量為0.0200cph/cm2以下。 (14) The Cu core sphere described in any one of the above items (11) to (13), wherein the amount of α ray is 0.0200 cph/cm 2 or less.
(15)如上述(11)至(13)項中任一項所述之Cu核球，其中α線量為0.0010cph/cm2以下。 (15) The Cu core sphere described in any one of the above items (11) to (13), wherein the amount of α rays is 0.0010 cph/cm 2 or less.
(16)如上述(1)至(15)項中任一項所述之Cu核球，其中Cu球的直徑為1μm以上且1000μm以下。 (16) The Cu core sphere as described in any one of the above items (1) to (15), wherein the diameter of the Cu sphere is 1 μm or more and 1000 μm or less.
(17)一種焊接頭，係使用如上述(1)至(16)項中任一項所述之Cu核球。 (17) A welding joint using the Cu core ball described in any one of the above items (1) to (16).
(18)一種焊膏，係使用如上述(1)至(16)項中任一項所述之Cu核球。 (18) A solder paste using the Cu nuclei as described in any one of the above items (1) to (16).
(19)一種泡沫焊料，係使用如上述(1)至(16)項中任一項所述之Cu核球。 (19) A solder foam using the Cu nuclei as described in any one of the above items (1) to (16).
依照本發明，實現Cu球為高真球度及低硬度且能夠抑制Cu球變色。藉由實現Cu球的高真球度，能夠實現使用金屬層被覆Cu球而成之Cu核球的高真球度，而且將Cu核球封裝在電極上時能夠確保自對準性之同時，能夠抑制Cu核球高度的偏差。又，藉由實現Cu球的低硬度，在使用金屬層被覆Cu球而成之Cu核球亦能夠提升耐落下衝擊性。而且因為能夠抑制Cu球變色，所以能夠抑制硫化物和硫氧化物對Cu球造成不良影響，而且適合於使用金屬層的被覆且濕潤性變為良好。 According to the present invention, high true sphericity and low hardness of Cu balls can be realized and discoloration of Cu balls can be suppressed. By realizing the high sphericity of Cu balls, it is possible to realize the high sphericity of Cu core balls formed by coating Cu balls with a metal layer, and when encapsulating Cu core balls on electrodes, self-alignment can be ensured, Variation in Cu nuclei height can be suppressed. In addition, by realizing the low hardness of the Cu balls, the drop impact resistance can also be improved by using the Cu core balls in which the Cu balls are covered with a metal layer. Furthermore, since discoloration of Cu balls can be suppressed, adverse effects of sulfides and sulfur oxides on Cu balls can be suppressed, and it is suitable for coating with a metal layer and has good wettability.
用以實施發明之形態form for carrying out the invention
以下更詳細地說明本發明，在本說明書，有關Cu核球的金屬層組成之單位(ppm、ppb、及%)，係只要沒有特別指定，就表示相對於金屬層的質量之比率(質量ppm、質量ppb、及質量%)。又，有關Cu球的組成之單位(ppm、ppb、及%)，係只要沒有特別指定，就表示相對於Cu球的質量之比率(質量ppm、質量ppb、及質量%)。The present invention will be described in more detail below. In this specification, the units (ppm, ppb, and %) of the composition of the metal layer of the Cu nuclei are, unless otherwise specified, the ratio (mass ppm) relative to the mass of the metal layer. , mass ppb, and mass %). In addition, the units (ppm, ppb, and %) concerning the composition of Cu balls represent ratios (ppm by mass, ppb by mass, and % by mass) relative to the mass of Cu balls unless otherwise specified.
第1圖係顯示本發明之第1實施形態的Cu核球11A的構成的一個例子。如第1圖顯示，本發明之第1實施形態的Cu核球11A，係具備Cu球1、及被覆Cu球1表面之焊料層3。Fig. 1 shows an example of the structure of a
第2圖係顯示本發明之第2實施形態的Cu核球11B的構成的一個例子。如第2圖顯示，本發明之第2實施形態的Cu核球11B，係具備Cu球1、被覆Cu球1表面之選自由Ni、Co、Fe、Pd之1種以上的元素所構成之1層以上的金屬層2、及被覆金屬層2表面之焊料層3。Fig. 2 shows an example of the structure of a
第3圖係顯示使用本發明之實施形態的Cu核球11A或Cu核球11B而將半導半導體晶片10搭載在印刷基板40上而成之電子零件60的構成的一個例子。如第3圖顯示，Cu核球11A或Cu核球11B係藉由將助焊劑塗佈在半導體晶片10的電極100且熔融後的焊料層3濕潤擴大而被封裝在半導體晶片10的電極100上。在本例，係將Cu核球11A或Cu核球11B封裝在半導體晶片10的電極100而成之構造稱為焊料凸塊30。半導體晶片10的焊料凸塊30係透過熔融後的焊料層3、或塗佈在電極41後的焊膏熔融後的焊料而接合在印刷基板40的電極41上。在本例，係將焊料凸塊30封裝在印刷基板40的電極41而成之構造稱為焊接頭50。FIG. 3 shows an example of the configuration of an
在各實施形態的Cu核球11A、11B，Cu球1係Fe、Ag及Ni之中至少1種的含量合計為5.0質量ppm以上且50.0質量ppm以下，S的含量為0質量ppm以上且1.0質量ppm以下，P的含量為0質量ppm以上且小於3.0質量ppm，剩餘部分為Cu及其它不純物元素，Cu球1的純度為4N5(99.995質量%)以上且5N5(99.9995質量%)以下，真球度為0.95以上。In the
本發明之第1實施形態的Cu核球11A係藉由提高經焊料層3被覆的Cu球1的真球度而能夠提高Cu核球11A的真球度。又，本發明之第2實施形態的Cu核球11B係藉由提高經金屬層2及焊料層3被覆的Cu球1的真球度而能夠提高Cu核球11B的真球度。以下，說明構成Cu核球11A、11B之Cu球1的較佳態樣。The
･Cu球的真球度：0.95以上 在本發明，所謂真球度係表示從真球起的偏移。真球度係表示將500個各Cu球的直徑除以長徑時所算出之算術平均值，該值係表示越接近上限之1.00，越接近真球。真球度係例如使用最小二次方中心法(LSC法)、最小區域中心法(MZC法)、最大內接中心法(MIC法)、最小外接中心法(MCC法)等各種方法求得。在本發明，所謂長徑的長度、及直徑的長度係指使用Mitutoyo公司製的Ultra Quick Vision、ULTRA QV350-PRO測定裝置而測定的長度。･Cu ball true sphericity: 0.95 or more In the present invention, the so-called true sphericity system means a deviation from a true sphere. True sphericity means the arithmetic mean value calculated by dividing the diameter of 500 Cu balls by the long diameter, and the value means that the closer to the upper limit of 1.00, the closer to a true sphere. The sphericity system is obtained by various methods such as least square center method (LSC method), minimum zone center method (MZC method), maximum inscribed center method (MIC method), and minimum circumscribed center method (MCC method). In the present invention, the length of the major diameter and the length of the diameter refer to lengths measured using Ultra Quick Vision and ULTRA QV350-PRO measuring devices manufactured by Mitutoyo Corporation.
Cu球1係從保持基板間的適當空間之觀點而言，真球度係以0.95以上為佳、真球度係以0.98以上為較佳，以0.99以上為更佳，Cu球1的真球度小於0.95時，因為Cu球1成為不定形狀，所以凸塊形成時形成高度不均勻的凸塊且產生接合不良之可能性提高。真球度為0.95以上時，因為Cu球1係在焊接的溫度不熔融，能夠抑制在焊接頭50在高度的偏差。藉此，能夠確實地防止半導體晶片10與印刷基板40的接合不良。From the perspective of maintaining an appropriate space between the substrates,
･Cu球的純度：99.995質量%以上且99.9995質量%以下
通常相較於純度較高的Cu，因為純度較低的Cu因為能夠確保在Cu中成為Cu球1的結晶核之不純物元素，所以真球度較高。另一方面，純度較低的Cu球1之導電度和熱傳導率劣化。･Purity of Cu balls: 99.995% by mass to 99.9995% by mass
Generally, compared with Cu with higher purity, Cu with lower purity can ensure the impurity element in Cu that becomes the crystallization nucleus of
因此，Cu球1係純度為99.995質量%(4N5)以上且99.9995質量%(5N5)以下時，能夠確保充分的真球度。又，Cu球1的純度為4N5以上且5N5以下時，不僅能夠充分地減低α線量，而且能夠抑制純度降低引起Cu球1的導電度和熱傳導率劣化。Therefore, when the purity of the
在製造Cu球1時，經形成為預定形狀的小片之金屬材料的一個例子的Cu材，係藉由加熱而熔融且熔融Cu利用表面張力而成為球形，藉由急冷將其凝固而成為Cu球1。在熔融Cu從液體狀態起進行凝固之過程，結晶粒係在球形的熔融Cu中成長。此時，不純物元素較多時、該不純物元素係成為結晶核且抑制結晶粒成長。因而，球形的熔融Cu係藉由經抑制成長的微細結晶粒而成為真球度較高的Cu球1。另一方面，不純物元素較少時，因為相對地成為結晶核之物較少，所以粒成長未被抑制且帶有某方向性而成長。該結果，球形的熔融Cu係表面的一部分為突出而凝固且真球度為變低。作為不純物元素，能夠考慮Fe、Ag、Ni、P、S、Sb、Bi、Zn、Al、As、Cd、Pb、In、Sn、Au、U、Th等。When manufacturing the
以下，說明規範Cu球1的純度及真球度之不純物的含量。Hereinafter, the content of impurities that regulate the purity and true sphericity of the
･Fe、Ag及Ni之中至少1種的含量合計：5.0質量ppm以上且50.0質量ppm以下
Cu球1所含有的不純物元素之中，Fe、Ag及Ni之中至少1種的含量合計係以5.0質量ppm以上且50.0質量ppm以下為特佳。亦即，Fe、Ag及Ni之中含有任1種時，1種的含量係以5.0質量ppm以上且50.0質量ppm以下為佳，Fe、Ag及Ni之中含有2種以上時，2種以上的合計含量係以5.0質量ppm以上且50.0質量ppm以下為佳。因為Fe、Ag及Ni係在Cu球1的製造步驟之熔融時成為結晶核，所以在Cu中含有一定量的Fe、Ag或Ni時，能夠製造真球度較高的Cu球1。因而，Fe、Ag及Ni之中，至少1種係為了推定不純物元素的含量而成為重要的元素。又，藉由Fe、Ag及Ni之中至少1種的含量合計為5.0質量ppm以上且50.0質量ppm以下，不僅能夠抑制Cu球1的變色，而且將Cu球1緩慢地加熱之後，藉由慢慢冷卻，即便不進行使Cu球1緩慢地再結晶之退火步驟，亦能夠實現所需要的維氏硬度。･The total content of at least one of Fe, Ag, and Ni: 5.0 mass ppm or more and 50.0 mass ppm or less
Among the impurity elements contained in the
･S的含量為0質量ppm以上且1.0質量ppm以下
含有預定量以上的S之Cu球1，因為加熱時係形成硫化物和硫氧化物而容易變色且濕潤性低，所以S的含量必須成為0質量ppm以上且1.0質量ppm以下。硫化物和硫氧化物越多而形成的Cu球1，Cu球表面的亮度變為越暗。因此，在後面詳述，測定Cu球表面的亮度之結果為預定值以下時，能夠抑制硫化物和硫氧化物的形成且能夠判定濕潤性為良好。･S content is 0 mass ppm or more and 1.0 mass ppm or
･P的含量為0質量ppm以上且小於3.0質量ppm
P係變化成為磷酸、或成為Cu錯合物而有對Cu球1造成不良影響之情形。又，因為預定量含有P之Cu球1係硬度變大，所以P的含量係以0質量ppm以上且小於3.0質量ppm為佳，以小於1.0質量ppm為較佳。･P content is 0 mass ppm or more and less than 3.0 mass ppm
The P system changes into phosphoric acid or into a Cu complex, which may adversely affect the
･其它不純物元素
Cu球1所含有之上述不純物元素以外的Sb、Bi、Zn、Al、As、Cd、Pb、In、Sn、Au等的不純物元素(以下稱為「其它不純物元素」)的含量，係各自以0質量ppm以上且小於50.0質量ppm為佳。･Other impurity elements
The content of impurity elements such as Sb, Bi, Zn, Al, As, Cd, Pb, In, Sn, Au (hereinafter referred to as "other impurity elements") other than the above-mentioned impurity elements contained in the
又，Cu球1係如上述，含有Fe、Ag及Ni之中至少1種作為必要元素。但是因為Cu球1係依照現在的技術，無法防止Fe、Ag、Ni以外的元素混入，所以實質上含有Fe、Ag、Ni以外的其它不純物元素。但是其它不純物元素的含量為小於1質量ppm時，添加各元素之效果、及影響不容易顯現。又，分析在Cu球所含有的元素時，不純物元素的含量小於1質量ppm時，該值係使用分析裝置之檢測界限以下。因此，Fe、Ag及Ni之中、至少1種的含量合計為50質量ppm時，其它不純物元素的含量為小於1質量ppm時，Cu球1的純度係實質上為4N5(99.995質量%)。又，Fe、Ag及Ni之中、至少1種的含量合計為5質量ppm時，其它不純物元素的含量為小於1質量ppm時，Cu球1的純度係實質上為5N5(99.9995質量%)。In addition, the
･Cu球的維氏硬度：55.5HV以下
Cu球1的維氏硬度係以55.5HV以下為佳。維氏硬度為較大時，對來自外部的應力之耐久性變低且耐落下衝擊性變差之同時，容易產生龜裂。又，在三維封裝的凸塊和接頭的形成時賦予加壓等的輔助力之情況，使用較硬的Cu球時有引起電極塌陷等之可能性。而且，Cu球1的維氏硬度較大時，由於結晶粒係一定以上地變小而有引起導電性劣化之緣故。Cu球1的維氏硬度為55.5HV以下時，耐落下衝擊性亦良好且能夠抑制龜裂，而且亦能夠抑制電極塌陷等且亦能夠抑制導電性劣化。本實施例係維氏硬度的下限為可為大於0HV，較佳為20HV以上。･Vickers hardness of Cu ball: 55.5HV or less
The Vickers hardness of the
･Cu球的α線量：0.0200cph/cm2
以下
在電子零件的高密度封裝，為了設為軟錯誤不成為問題的程度之α線量，Cu球1的α線量係以0.0200cph/cm2
以下為佳。從抑制在進一步高密度封裝的軟錯誤之觀點而言，α線量係良好為0.0100cph/cm2
以下，較佳為0.0050cph/cm2
以下，更佳為0.0020cph/cm2
以下，最佳為0.0010cph/cm2
以下。為了抑制α線量引起軟錯誤，U、Th等的放射性同位元素含量係以小於5質量ppb為佳。･The amount of α radiation of Cu ball: 0.0200cph/cm 2 or less In order to set the amount of α radiation to the extent that soft errors do not become a problem in high-density packaging of electronic parts, the amount of α radiation of
･耐變色性：亮度為55以上
Cu球1之亮度係以55以上為佳。所謂亮度係L*a*b*表色系的L*值。因為在表面形成有源自S的硫化物和硫氧化物之Cu球1的亮度變低，亮度為55以上時，可說是能夠抑制硫化物和硫氧化物。又，亮度為55以上的Cu球1係在封裝時之濕潤性良好。相對於此，Cu球1的亮度小於55時，可說是無法充分地抑制形成硫化物和硫氧化物之Cu球1。硫化物和硫氧化物不僅對Cu球1造成不良影響，而且在如將Cu球1直接接合在電極上時濕潤性變差。濕潤性變差係引起不濕潤的產生和自對準性劣化。
･Resistance to discoloration: Brightness of 55 or higher
The brightness of the
．Cu球的直徑：1μm以上且1000μm以下 ． Cu ball diameter: 1 μm or more and 1000 μm or less
Cu球1的直徑係以1μm以上且1000μm以下為佳，較佳為50μm以上且300μm以下。在該範圍時，能夠穩定地製造球狀的Cu球1，而且能夠抑制端子之間為狹窄間距時的連接短路。在此，例如Cu球1係被使用在膏狀物時，「Cu球」亦可稱為「Cu粉」。「Cu球」係被使用在「Cu粉」時，通常Cu球的直徑係以1~300μm為佳。
The diameter of the
其次，說明在本發明之第1實施形態的Cu核球11A，被覆Cu球1之焊料層3，及在第2實施形態的Cu核球11B，被覆金屬層2之焊料層3。
Next, the
．焊料層 ． Solder layer
本發明之各實施形態的Cu核球11A、11B，係藉由使用含有Sn及Cu作為必要元素的焊料合金之焊料層3被覆Cu球1而成之物。特別是本發明之各實施形態的Cu核球11A、11B係成為焊料層3中的Cu分布均勻之Cu核球、及提供一種使用該核球之焊接頭、焊膏、泡沫焊料之物。
The
本發明之實施形態的焊料層3之組成，係由含有Sn及Cu之(Sn-Cu)系合金所構成。針對Sn的含量，係相對於合金全體以40.0質量%以上為佳。針對Cu的含量，係相對於合金全體，Cu量為大於0質量%且3.0質量%以下的範圍，當Cu量為大於0質量%且3.0質量%以下的範圍時，能夠將Cu的濃度比率控制在預定範圍內。而且，相對於合金全體，Cu量為0.1~3.0質量%的範圍時，能夠將Cu的濃度比率控制70.0~130.0%的預定範圍內且能夠使焊料層3中的Cu分布成為均質。The composition of the
例如Cu的含量之目標值為0.7質量%時，作為Cu的含量及濃度比率的容許範圍為0.51質量(濃度比率72.9%)~0.68質量%(濃度比率97.1%)，能夠將Cu的濃度比率控制在70.0~130.0%的預定範圍內且能夠使焊料層3中的Cu分布成為均質。將目標值之Cu的含量為0.7質量%之焊料合金稱為(Sn-0.7Cu)系焊料合金。For example, when the target value of Cu content is 0.7% by mass, the allowable range of Cu content and concentration ratio is 0.51% by mass (concentration ratio 72.9%)~0.68 mass% (concentration ratio 97.1%), and the concentration ratio of Cu can be controlled Within the predetermined range of 70.0 to 130.0%, Cu distribution in the
又，Cu的含量之目標值為3.0質量%時，Cu的含量及濃度比率的容許範圍為2.45質量(濃度比率81.7%)~3.26質量%(濃度比率108.7%)，能夠將Cu的濃度比率控制在70.0~130.0%的預定範圍內且能夠使焊料層3中的Cu分布成為均質。將目標值之Cu的含量為3.0質量%之焊料合金稱為(Sn-3Cu)系焊料合金。Also, when the target value of the Cu content is 3.0% by mass, the allowable range of the Cu content and the concentration ratio is 2.45% by mass (81.7% concentration ratio) to 3.26% by mass (108.7% concentration ratio), and the Cu concentration ratio can be controlled Within the predetermined range of 70.0 to 130.0%, Cu distribution in the
而且，所謂容許範圍，係在該範圍內時，能夠沒有問題地進行凸塊形成等的焊接之範圍。又，所謂濃度比率(%)，係相對於目標含量(質量%)之計量值(質量%)、或相對於目標含量(質量%)之計量值的平均值(質量%)之比率(%)。亦即，濃度比率(%)係能夠以 濃度比率(%)=(計量值(質量%)/目標含量(質量%))×100 或、 濃度比率(%)=(計量值的平均值(質量%)/目標含量(質量%))×100之方式表示。In addition, the "permissible range" refers to a range in which soldering such as bump formation can be performed without any problem within this range. Also, the concentration ratio (%) is the ratio (%) of the measured value (mass %) to the target content (mass %), or the average value (mass %) of the measured value of the target content (mass %) . That is, the concentration ratio (%) can be expressed as Concentration ratio (%)=(measurement value (mass%)/target content (mass%))×100 or, Concentration ratio (%) = (average value of measured value (mass %)/target content (mass %)) × 100.
Cu的濃度比率係以90.0~110.0%的範圍內為較佳。又，即便在由Sn、Cu所構成之二元焊料層3中添加此外的添加元素，亦能夠將Cu的濃度比率控制在70.0~130.0%、較佳為90.0~110.0%的預定範圍內。The concentration ratio of Cu is preferably in the range of 90.0 to 110.0%. Also, even if other additive elements are added to the
作為添加元素，係能夠考慮使用Ag、Ni、Ge、Ga、In、Zn、Fe、Pb、Bi、Sb、Au、Pd、Co等之中一種或二種以上。As an additive element, one or two or more of Ag, Ni, Ge, Ga, In, Zn, Fe, Pb, Bi, Sb, Au, Pd, Co, etc. can be used.
如上述，焊料層3中的Cu含量係相對於目標值的0.7質量%，作為容許範圍係以0.51質量%(濃度比率72.9%)~0.68質量%(濃度比率97.1%)左右為佳。又，焊料層3中的Cu含量係相對於目標值的3.0質量%，作為容許範圍係以2.45質量%(濃度比率81.7%)~3.26質量%(濃度比率108.7%)左右為佳。As mentioned above, the Cu content in the
焊料層3的厚度亦依照Cu球1的粒徑而不同，為了確保充分的焊接量，徑向的一側係以100μm以下為佳。焊料層3能夠藉由習知的電鍍、無電解電鍍而形成，但是藉由熔融電鍍而形成焊料層時，Cu球的粒徑變小時焊料層的膜厚不均勻，而且在Cu核球中的Cu球的偏心和焊料層表面的凹凸變大且Cu核球的真球度低落。因此，焊料層3係藉由電鍍處理而形成。The thickness of the
作為電鍍液，係在將水作為主體之介質中含有有機酸類及作為金屬成分之Sn及Cu作為必要成分。金屬成分係在電鍍液中以Sn離子(Sn2+ 及/或Sn4+ )及Cu離子(Cu+ /Cu2+ )之方式存在。電鍍液係主要是將由水及有機酸類所構成的電鍍母液及金屬化合物混合而得到，為了金屬離子的安定性，較佳是含有有機錯合劑。The plating solution contains organic acids and Sn and Cu as metal components as essential components in a medium mainly composed of water. Metal components exist in the form of Sn ions (Sn 2+ and/or Sn 4+ ) and Cu ions (Cu + /Cu 2+ ) in the electroplating solution. The electroplating solution is mainly obtained by mixing an electroplating mother solution composed of water and organic acids and a metal compound. For the stability of metal ions, it is preferable to contain an organic complexing agent.
作為電鍍液中的金屬化合物，例如能夠例示以下之物。作為Sn化合物的具體例，可舉出甲磺酸、乙磺酸、2-丙醇磺酸、對酚磺酸等的有機磺酸的錫鹽、硫酸錫、氧化錫、硝酸錫、氯化錫、溴化錫、碘化錫、磷酸錫、焦磷酸錫、乙酸錫、甲酸錫、檸檬酸錫、葡糖酸錫、酒石酸錫、乳酸錫、琥珀酸錫、胺基磺酸錫、氟硼酸錫、氟矽酸錫等的亞Sn化合物。該等Sn化合物係能夠混合一種單獨或二種以上而使用。As a metal compound in a plating solution, the following can be illustrated, for example. Specific examples of Sn compounds include tin salts of organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, 2-propanolsulfonic acid, and p-phenolsulfonic acid, tin sulfate, tin oxide, tin nitrate, and tin chloride. , tin bromide, tin iodide, tin phosphate, tin pyrophosphate, tin acetate, tin formate, tin citrate, tin gluconate, tin tartrate, tin lactate, tin succinate, tin sulfamate, tin fluoroborate , Sub-Sn compounds such as tin fluorosilicate. These Sn compounds can be used alone or in combination of two or more.
作為Cu化合物，可舉出上述有機磺酸的銅鹽、硫酸銅、氧化銅、硝酸銅、氯化銅、溴化銅、碘化銅、磷酸銅、焦磷酸銅、乙酸銅、甲酸銅、檸檬酸銅、葡糖酸銅、酒石酸銅、乳酸銅、琥珀酸銅、胺基磺酸銅、氟硼酸銅、氟矽酸銅等。該等Cu合物能夠一種單獨或混合二種以上而使用。Examples of the Cu compound include copper salts of the aforementioned organic sulfonic acids, copper sulfate, copper oxide, copper nitrate, copper chloride, copper bromide, copper iodide, copper phosphate, copper pyrophosphate, copper acetate, copper formate, lemon Copper acid, copper gluconate, copper tartrate, copper lactate, copper succinate, copper sulfamate, copper fluoborate, copper fluosilicate, etc. These Cu compounds can be used alone or in combination of two or more.
藉由電鍍而形成由Sn及Cu所構成之Sn-Cu系焊料合金組成的焊料層時，因為Cu比Sn更優先被收納至焊料層，所以有電鍍液中的Cu濃度與焊料層中的Cu量不一致之問題，且Cu的濃度分布無法形成均勻的焊料層。因此在陽極電極與陰極電極之間施加預定直流電壓之同時，能夠藉由邊使Cu球搖動邊使液中的Cu濃度成為之方式調整而進行電鍍處理，且以電鍍液的濃度在焊料電鍍層形成中成為一定的方式控制。When a solder layer composed of a Sn-Cu based solder alloy composed of Sn and Cu is formed by electroplating, since Cu is preferentially accommodated in the solder layer compared to Sn, there is a difference between the Cu concentration in the plating solution and the Cu concentration in the solder layer. The problem of inconsistency in the amount, and the concentration distribution of Cu cannot form a uniform solder layer. Therefore, while applying a predetermined DC voltage between the anode electrode and the cathode electrode, the plating process can be performed by adjusting the concentration of Cu in the solution while shaking the Cu ball, and the concentration of the plating solution is applied to the solder plating layer. Formation becomes controlled in a certain way.
在藉由使電鍍液的濃度在焊料電鍍層形成中成為一定的方式控制之電鍍處理而生成焊料層3之過程，係仔細地監控焊料層3的厚度，在該例子係將焊料層3的厚度每次預定值依序增加時的Cu核球，每次採集作為試樣。所採集的試樣係洗淨後使其乾燥之後，進行計量粒徑。In the process of producing the
得知計量時序的Cu核球的粒徑成為目標值時依次測定焊料層中的Cu含量時，即便焊料層依序增加預定厚度，此時的Cu含量係與之前的含量為大約相同值。因而，能夠理解Cu的濃度分布係相對於電鍍厚度為均勻(均等)且無濃度梯度。如以上，膜厚能夠均勻地控制能夠之反面，針對濃度不均勻之電鍍的問題點，係能夠藉由控制焊料層中的Cu濃度使Cu濃度比率落入預定範圍內而能夠得到具有Cu均勻分布的焊料層之Cu核球。When the Cu content in the solder layer is sequentially measured when the particle size of the Cu nuclei in the measurement sequence becomes the target value, the Cu content at this time is approximately the same as the previous content even if the solder layer is sequentially increased by a predetermined thickness. Therefore, it can be understood that the concentration distribution of Cu is uniform (equal) with respect to the plating thickness and has no concentration gradient. As above, the film thickness can be uniformly controlled. On the other hand, for the problem of electroplating with uneven concentration, it is possible to obtain a uniform distribution of Cu by controlling the Cu concentration in the solder layer so that the Cu concentration ratio falls within a predetermined range. The Cu nuclei of the solder layer.
第4圖係Cu核球的放大剖面圖。在第4圖，係顯示使用金屬層2被覆Cu球1且使用焊料層3被覆金屬層2而成之Cu核球11B。從第4圖能夠清楚知道焊料層3之Sn及Cu係邊均質地摻雜邊成長的過程。Fig. 4 is an enlarged cross-sectional view of a Cu nuclei sphere. In FIG. 4 ,
又，因為被覆Cu核球11A、11B之焊料層3的最表面越接近單一金屬的狀態，結晶粒越大，所以Cu核球的真球度降低之傾向。相對於此，因為焊料層中的Cu為大約均質分布的狀態，所以焊料層的最表面不是單一金屬而成為合金狀態且結晶粒變小。藉此，Cu核球的真球度較高之0.99以上。Cu核球的真球度為0.95以上時，將Cu核球搭載在電極而進行回流時，能夠抑制Cu核球產生位置偏移且自對準性提升。Also, since the outermost surface of the
因為焊料層中的Cu濃度係即便焊料層的厚度成長亦維持大約相同狀態，清楚明白焊料層中的Cu係在大約均質分布的狀態下成長。能夠以Cu濃度落入預期值內之方式且在使電鍍液中的Cu濃度成為均質的狀態下進行電鍍處理。在該例子，因為焊料層中的Cu含量係將0.7質量%或3.0質量%作為目標值，所以能夠以到達目標值之方式控制電鍍液中的Cu濃度。Since the Cu concentration system in the solder layer maintains approximately the same state even if the thickness of the solder layer grows, it is clear that the Cu system in the solder layer grows in a state of approximately uniform distribution. The plating treatment can be performed in a state where the Cu concentration in the plating solution is made homogeneous so that the Cu concentration falls within a desired value. In this example, since the Cu content in the solder layer has a target value of 0.7% by mass or 3.0% by mass, it is possible to control the Cu concentration in the plating solution so as to reach the target value.
為了使焊料層中的Cu濃度分布落入預期值，係邊進行電壓･電流控制邊電鍍處理。藉由此種電鍍處理而能夠將焊料層中的Cu分布維持在預期值。In order to make the Cu concentration distribution in the solder layer fall into the expected value, the electroplating process is performed while controlling the voltage and current. Cu distribution in the solder layer can be maintained at a desired value by such plating treatment.
Cu核球11A、11B，亦可藉由在焊料層3使用低α線量的焊料合金，來構成低α線的Cu核球11A、11B。
其次，說明在本發明之第2實施形態的Cu核球11B之被覆Cu球1的金屬層2。Next, the
･金屬層
金屬層2係例如由包含2層以上的鍍Ni層、鍍Co層、鍍Fe層、鍍Pd層、或Ni、Co、Fe、Pd的元素之電鍍層(單層或複數層)所構成。金屬層2係在Cu核球11B被使用在焊料凸塊時之焊接的溫度為不熔融而殘留且有助於焊接頭的高度之緣故，所以能夠真球度較高且直徑的偏差為較少而構成。又，從抑制軟錯誤之觀點而言，能夠以α線量變低之方式而構成。･Metal layer
The
･金屬層的組成及膜層
金屬層2的組成係使用單一的Ni、Co、Fe或Pd而構成金屬層2時，除了不可避免的不純物以外，Ni、Co、Fe、Pd為100%。又，使用在金屬層2之金屬係不被單一金屬限定，亦可使用從Ni、Co、Fe或Pd之中組合2元素以上而成之合金。而且，金屬層2可為由單一的Ni、Co、Fe或Pd所構成之層，亦可為將從Ni、Co、Fe或Pd之中組合2元素以上而成的合金之層適當地組合而成之複數層所構成。金屬層2的膜厚T2係例如1μm~20μm。
･Composition and film layer of the metal layer
The composition of the
．Cu核球的α線量：0.0200cph/cm2以下 ． The amount of α line of Cu nuclei: below 0.0200cph/cm 2
本發明之第1實施形態的Cu核球11A及第2實施形態的Cu核球11B之α線量，係以0.0200cph/cm2以下為佳。這是在電子零件的高密度封裝軟錯誤不成為問題的程度之α線量。本發明之第1實施形態的Cu核球11A的α線量，係能夠藉由構成Cu核球11A之焊料層3的α線量為0.0200cph/cm2以下而達成。因而，因為本發明之第1實施形態的Cu核球11A係經此種焊料層3被覆，所以顯示較低的α線量。本發明之第2實施形態的Cu核球11B的α線量，係能夠藉由構成Cu核球11B之金屬層2及焊料層3的α線量為0.0200cph/cm2以下而達成。因而，本發明之第2實施形態的Cu核球11B係經此種金屬層2及焊料層3被覆，所以顯示較低的α線量。從抑制在進一步高密度封裝的軟錯誤之觀點而言，α線量係良好為0.0100cph/cm2以下，較佳為0.0050cph/cm2以下，更佳為0.0020cph/cm2以下，最佳為0.0010cph/cm2以下。為了將Cu球1的α線量設為0.0200cph/cm2以下，金屬層2及焊料層3的U及Th的含量係各自5ppb以下。又，從抑制現在或將來的高密度封裝的軟錯誤之觀點而言，U及Th的含量係較佳為各自2ppb以下。
The amount of α rays of the
．Cu核球的真球度：0.95以上 ． True sphericity of Cu nuclei: 0.95 or more
經焊料層3被覆Cu球1之本發明的第1實施形態的Cu核球11A、及經金屬層2及焊料層3被覆Cu球1之本發明的第2實施形態的Cu核球11B的真球度，係以0.95以上為佳，真球度係以0.98以上為較佳，以0.99以上為更佳。
The
Cu核球11A、11B的真球度小於0.95時，因為Cu核球11A、11B成為不定形狀，所以將Cu核球11A、11B搭載在電極而進行回流時，Cu核球11A、11B產生位置偏移且自對準性亦變差。Cu核球11A、11B的真球度為0.95以上時，能夠確保將Cu核球11A、11B封裝在半導體晶片10的電極100等時之自對準性。而且，藉由Cu球1的真球度亦為0.95以上，因為Cu核球11A、11B在將Cu球1及金屬層2焊接的溫度不熔融，所以能夠抑制在焊接頭50之高度的偏差。藉此，能夠確實地防止半導體晶片10與印刷基板40的接合不良。When the true sphericity of the Cu nuclei 11A, 11B is less than 0.95, since the Cu nuclei 11A, 11B become indeterminate shapes, when the Cu nuclei 11A, 11B are mounted on the electrodes and reflowed, the Cu nuclei 11A, 11B are misaligned. shift and self-alignment also deteriorates. When the true sphericity of the
･金屬層的阻障功能
在回流時，在為了將Cu核球與電極間接合而使用之焊料(膏)中，Cu球的Cu產生擴散時，在焊料層中及接續界面係大量地形成較硬且較脆的Cu6
Sn5
、Cu3
Sn金屬間化合物且受到衝擊時，有龜裂進展且將連接部破壞之可能性。因此為了得到充分的連接強度，係能夠抑制(阻障)Cu從Cu球往焊料擴散即可。因此，在第2實施形態的Cu核球11B，因為在Cu球1的表面形成作為阻障層的功能之金屬層2，所以能夠抑制Cu球1的Cu擴散至膏狀物的焊料中。･Barrier function of the metal layer During reflow, in the solder (paste) used to join the Cu core ball and the electrode, when Cu of the Cu ball diffuses, a large amount of thinner is formed in the solder layer and at the connection interface. Hard and brittle Cu 6 Sn 5 , Cu 3 Sn intermetallic compounds may develop cracks and destroy the connection part when impacted. Therefore, in order to obtain sufficient connection strength, it is only necessary to suppress (block) the diffusion of Cu from the Cu balls to the solder. Therefore, in the
･焊膏、泡沫焊料、焊接頭
又，亦能夠藉由使焊料含有Cu核球11A或Cu核球11B而構成焊膏。藉由使Cu核球11A或Cu核球11B分散在焊料中，能夠構成泡沫焊料。Cu核球11A或Cu核球11B亦能夠使用於形成將電極間接合之焊接頭。･Solder paste, foam solder, solder tip
In addition, it is also possible to constitute a solder paste by adding Cu nuclei
･Cu球的製造方法
其次，說明Cu球1的製造方法的一個例子。作為金屬材料的一個例子，係將Cu材放置在如陶瓷之耐熱性板(以下稱為「耐熱板」)且與耐熱板一起在爐中加熱。耐熱板之底部係設置有許多半球狀的圓形溝。溝的直徑和深度係能夠按照Cu球1的粒徑而適當地設定，例如直徑0.8mm、深度0.88mm。又，將Cu細線切斷而得到的晶片形狀Cu材每次一個投入至耐熱板的溝內。在溝內投入有Cu材之耐熱板，係在填充有氨分解氣體之爐內被升溫至1100~1300℃且進行加熱處理30~60分鐘。此時爐內溫度成為Cu的熔點以上時，Cu材係熔融且成為球狀。隨後，將爐內冷卻且藉由在耐熱板的溝內將Cu球1急冷而成形。･Cu ball manufacturing method
Next, an example of a method of manufacturing
又，作為另外的方法，係有將熔融Cu從設置在坩堝底部的孔口滴下，將該液滴冷卻至室溫(例如25℃)為止而造球成為Cu球1之霧化法；及熱電漿將Cu切割金屬加熱至1000℃以上而造球之方法。Also, as another method, there is an atomization method in which molten Cu is dropped from an orifice provided at the bottom of the crucible, and the droplet is cooled to room temperature (for example, 25° C.) to form
在Cu球1的製造方法，亦可在造球形成Cu球1之前，將Cu球1的原料之Cu材在800~1000℃進行加熱處理。In the manufacturing method of the
作為Cu球1的原料之Cu材，例如能夠使用塊狀金屬(nugget)材、金屬線材、板材等。從不使Cu球1的純度過度降低的觀點而言，Cu材的純度係大於4N5且6N以下即可。As a Cu material as a raw material of the
如此，使用高純度的Cu材時，係可以不進行前述的加熱處理，而且將熔融Cu的保持溫度與先前同樣地降低至1000℃左右。如此，前述的加熱處理係可按照Cu材的純度和α線量而適當地省略和變更。又，製成α線量較高的Cu球1和異形的Cu球1時，亦可將該等Cu球1作為原料而再利用且能夠使α線量降低。In this way, when using a high-purity Cu material, it is not necessary to perform the above-mentioned heat treatment, and the holding temperature of molten Cu can be lowered to about 1000° C. as before. In this way, the aforementioned heat treatment system can be appropriately omitted or changed according to the purity of the Cu material and the amount of α radiation. In addition, when producing
作為將焊料層3形成在所製成的Cu球1之方法，係能夠採用上述的電鍍法或無電解電鍍法。As a method of forming the
作為將金屬層2形成在所製成的Cu球1之方法，係能夠採用習知的電解電鍍法等方法。例如形成鍍Ni層時，係針對鍍Ni的浴種，藉由使用Ni金屬塊(bullion)或Ni金屬鹽而調製鍍Ni液，將Cu球1浸漬且使其析出而將鍍Ni層形成在Cu球1的表面。又，作為形成鍍Ni層等的金屬層2之其它方法，亦能夠採用習知的無電解電鍍法等。使用Sn合金而將焊料層3形成在金屬層2的表面時，能夠採用上述的電鍍法或無電解電鍍法。
[實施例]As a method of forming the
以下，說明本發明的實施例，但是本發明係不被該等限定。使用以下的表1、表2顯示之組成而製造實施例1~19及比較例1~12的Cu球，而且測定該Cu球的真球度、維氏硬度、α線量及耐變色性。Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. Cu balls of Examples 1 to 19 and Comparative Examples 1 to 12 were manufactured using the compositions shown in Table 1 and Table 2 below, and the true sphericity, Vickers hardness, α ray content, and discoloration resistance of the Cu balls were measured.
又，將上述實施例1~19的Cu球，藉由使用表3顯示組成例1~2的焊料合金之焊料層進行被覆而製造實施例1A~19A的Cu核球且測定該Cu核球的真球度。而且，將上述實施例1~19的Cu球，藉由金屬層及使用表4顯示組成例1~2的焊料合金之焊料層進行被覆而製造實施例1B~19B的Cu核球且測定該Cu核球的真球度。In addition, the Cu balls of Examples 1 to 19 described above were coated with the solder layer of the solder alloy of the composition examples 1 to 2 shown in Table 3 to manufacture Cu core balls of Examples 1A to 19A, and the Cu core balls of the Cu core balls were measured. true sphericity. Furthermore, the Cu balls of Examples 1 to 19 described above were coated with a metal layer and a solder layer using the solder alloys of the composition examples 1 to 2 shown in Table 4 to manufacture Cu core balls of Examples 1B to 19B, and the Cu nuclei of Examples 1B to 19B were measured. True sphericity of the nuclei.
而且，藉由使用表5顯示之組成例1~2的焊料合金之焊料層被覆上述比較例1~12的Cu球，而製造比較例1A~12A的Cu核球且測定該Cu核球的真球度。又，藉由使用金屬層及表6顯示之組成例1~2的焊料合金之焊料層被覆上述比較例1~12的Cu球，而製造比較例1B~12B的Cu核球且測定該Cu核球的真球度。Furthermore, by coating the Cu balls of the above-mentioned Comparative Examples 1 to 12 with the solder layer of the solder alloys of the composition examples 1 to 2 shown in Table 5, the Cu core balls of Comparative Examples 1A to 12A were manufactured and the true diameter of the Cu core balls was measured. Sphericity. Also, by coating the Cu balls of Comparative Examples 1 to 12 with a metal layer and a solder layer of the solder alloys of Composition Examples 1 to 2 shown in Table 6, Cu core balls of Comparative Examples 1B to 12B were manufactured and the Cu core balls were measured. True sphericity of the ball.
下述表中，無單位的數字係表示質量ppm或質量ppb。詳言之，表中顯示Fe、Ag、Ni、P、S、Sb、Bi、Zn、Al、As、Cd、Pb、In、Sn、Au的含有比率之數值，係表示質量ppm。「>1」係表示該不純物元素對Cu球之含有比率為小於1質量ppm。又，表中顯示U、Th的含有比率之數值係表示質量ppb。「>5」係表示該不純物元素對Cu球之含有比率為小於5質量ppb。「不純物合計量」係表示Cu球所含有的不純物元素之合計比率。In the following tables, numbers without units represent mass ppm or mass ppb. Specifically, the values in the tables showing the content ratios of Fe, Ag, Ni, P, S, Sb, Bi, Zn, Al, As, Cd, Pb, In, Sn, and Au represent ppm by mass. ">1" means that the content ratio of the impurity element to the Cu ball is less than 1 mass ppm. In addition, the numerical values showing the content ratio of U and Th in the table represent mass ppb. ">5" means that the content ratio of the impurity element to the Cu ball is less than 5 mass ppb. The "total amount of impurities" indicates the total ratio of impurity elements contained in Cu balls.
･Cu球的製造 研討Cu球的製造條件。作為金屬材料的一個例子之Cu材，係準備塊狀金屬材。作為實施例1~13、19、比較例1~12的Cu材，係使用純度為6N之物，作為實施例14~18的Cu材，係使用純度為5N之物。將各Cu材投入至坩堝中之後，將坩堝的溫度升溫至1200℃且加熱45分鐘而使Cu材熔融，而且將熔融Cu從設置在坩堝底部的孔口滴下且將所生成的液滴急冷至室溫(18℃)為止來造球成為Cu球。藉此，製造平均粒徑成為下述各表顯示的值之Cu球。元素分析係能夠使用感應耦合電漿質量分析(ICP-MS分析)和輝光放電質量分析(GD-MS分析)而高精確度地分析。在本例，經藉由ICP-MS分析而進行的Cu球之球徑，係實施例1~實施例19、比較例1~12均設為250μm。･Manufacture of Cu balls Study the manufacturing conditions of Cu balls. As an example of a metal material, a Cu material is prepared as a bulk metal material. As the Cu material of Examples 1 to 13 and 19 and Comparative Examples 1 to 12, a product with a purity of 6N was used, and as the Cu material of Examples 14 to 18, a material with a purity of 5N was used. After putting each Cu material into the crucible, the temperature of the crucible was raised to 1200° C. and heated for 45 minutes to melt the Cu material, and the molten Cu was dropped from an orifice provided at the bottom of the crucible and the resulting droplet was rapidly cooled to At room temperature (18°C) to form spheres into Cu spheres. Thereby, the Cu ball whose average particle diameter became the value shown in each following table was manufactured. The elemental analysis system can be analyzed with high precision using inductively coupled plasma mass spectrometry (ICP-MS analysis) and glow discharge mass spectrometry (GD-MS analysis). In this example, the diameters of the Cu balls analyzed by ICP-MS were all set to 250 μm in Examples 1 to 19 and Comparative Examples 1 to 12.
．Cu核球的製造 ． Fabrication of Cu nuclei
使用上述實施例1~19的Cu球，針對實施例1A~19A，係以一側23μm的厚度且使用組成例1~2的焊料合金，藉由電鍍法而形成焊料層來製造實施例1A~19A的Cu核球。 Using the Cu balls of Examples 1 to 19 above, for Examples 1A to 19A, the thickness of one side is 23 μm and the solder alloy of Composition Examples 1 to 2 is used to form a solder layer by electroplating to manufacture Examples 1A to 19A. 19A Cu nuclei.
又，使用上述實施例1~19的Cu球，針對實施例1B~19B，係以一側2μm的厚度形成鍍Ni層作為金屬層，而且，以一側23μm的厚度且使用組成例1~2的焊料合金，藉由電鍍法而形成焊料層來製造實施例1B~19B的Cu核球。 In addition, using the Cu balls of Examples 1 to 19 above, for Examples 1B to 19B, a Ni plating layer was formed as a metal layer with a thickness of 2 μm on one side, and a thickness of 23 μm on one side was used in Composition Examples 1 to 2. A solder alloy was used to form a solder layer by electroplating to manufacture Cu nuclei in Examples 1B to 19B.
而且，使用上述比較例1~12的Cu球，係以一側23μm的厚度且使用組成例1~2的焊料合金而形成焊料層來製造比較例1A~12A的Cu核球。又，使用上述比較例1~12的Cu球以一側2μm的厚度形成鍍Ni層作為金屬層，而且，以一側23μm的厚度且使用組成例1~2的焊料合金形成焊料層來製造比較例1B~12B的Cu核球。 Then, using the Cu balls of Comparative Examples 1 to 12, the Cu core balls of Comparative Examples 1A to 12A were produced by forming a solder layer with a thickness of 23 μm on one side and using the solder alloy of Composition Examples 1 to 2. In addition, using the Cu balls of Comparative Examples 1 to 12 above, a Ni plating layer was formed as a metal layer with a thickness of 2 μm on one side, and a solder layer was formed with a thickness of 23 μm on one side using the solder alloys of Composition Examples 1 to 2 to manufacture comparative Example 1B~12B of Cu nuclei.
以下，詳述Cu球及Cu核球的真球度、Cu球的α線量、維氏硬度及耐變色性之各評價方法。 Hereinafter, each evaluation method of the true sphericity of Cu balls and Cu core balls, the amount of α rays of Cu balls, the Vickers hardness, and the resistance to discoloration will be described in detail.
．真球度 ． true sphericity
Cu球及Cu核球的真球度係使用CNC影像測定系統而測定。裝置為Mitutoyo公司製的Ultra Quick Vision、ULTRA QV350-PRO。 The true sphericity of Cu spheres and Cu core spheres is measured using a CNC image measuring system. The apparatuses were Ultra Quick Vision and ULTRA QV350-PRO manufactured by Mitutoyo Corporation.
[真球度的評價基準] [Evaluation criteria for true sphericity]
在下述的各表，Cu球及Cu核球的真球度之評價基準係如以下。 In each of the following tables, the evaluation criteria of the true sphericity of Cu balls and Cu core balls are as follows.
○○○：真球度為0.99以上 ○○○: true sphericity is above 0.99
○○：真球度為0.98以上且小於0.99 ○○: true sphericity is 0.98 or more and less than 0.99
○：真球度為0.95以上且小於0.98 ○: True sphericity is 0.95 or more and less than 0.98
×：真球度為小於0.95 ×: true sphericity is less than 0.95
．維氏硬度 ． Vickers hardness
Cu球的維氏硬度係依據「維氏硬度試驗-試驗方法JIS Z2244」而測定。裝置係使用明石製作所製的微型維氏硬度試驗器、Akashi微小硬度計MVK-F 12001-Q。The Vickers hardness of the Cu ball was measured in accordance with "Vickers hardness test-test method JIS Z2244". As the apparatus, a micro-Vickers hardness tester manufactured by Akashi Seisakusho, Akashi micro-hardness tester MVK-F 12001-Q was used.
[維氏硬度的評價基準] 在下述各表，Cu球的維氏硬度的評價基準係如以下。 ○：大於0HV且55.5HV以下 ×：大於55.5HV[Evaluation criteria for Vickers hardness] In each of the following tables, the evaluation criteria of the Vickers hardness of Cu balls are as follows. ○: Greater than 0HV and below 55.5HV ×: Greater than 55.5HV
．α線量 Cu球的α線量之測定方法係如以下。α線量的測定係使用氣流比例計數器的α線測定裝置。測定試樣係在300mm×300mm的平面淺底容器，將Cu球舖滿至無法看到容器的底部為止之物。將該測定試樣放入至α線測定裝置內且在PR-10氣流放置24小時之後，測定α線量。． α amount The method of measuring the amount of α rays of Cu balls is as follows. The measurement of the amount of α-rays uses an α-ray measuring device with an air flow proportional counter. The measurement sample is placed in a 300mm×300mm flat shallow-bottomed container, and the Cu balls are covered until the bottom of the container cannot be seen. This measurement sample was placed in an α ray measuring device and left to stand for 24 hours in the airflow of PR-10, and then the amount of α ray was measured.
[α線量的評價基準] 在下述各表，Cu球的α線量的評價基準係如以下。 ○：α線量為0.0200cph/cm2 以下 ×：α線量為大於0.0200cph/cm2 [Evaluation Criteria for α Radiation Amount] In each of the following tables, the evaluation criteria for the α ray amount of Cu balls are as follows. ○: The amount of α-ray is less than 0.0200cph/cm 2 ×: The amount of α-ray is more than 0.0200cph/cm 2
又，測定所使用的PR-10氣體(氬90%-甲烷10%)係將PR-10氣體填充在氣體高壓罐後經過3星期以上之物。使用經過3星期以上的高壓罐係依照JEDEC(Joint Electron Device Engineering Council；電子工程設計發展聯合協會)規定之JEDEC STANDARD-Alpha Radiation Measurement in Electronic Materials JESD221(JEDEC標準-電子材料之α 輻射測量JESD221)，使進入氣體高壓罐之大氣中的氡(radon)不產生α線之緣故。In addition, the PR-10 gas (argon 90%-
･耐變色性 為了測定Cu球的耐變色性，係使用大氣環境下的恆溫槽將Cu球在設定為200℃加熱420秒鐘且測定亮度的變化，而且進行評價Cu球是否充分地能夠經得起經時變化。亮度係使用、Konica Minolta製CM-3500d型分光測色計，在D65光源、10度視野且依據JIS Z 8722「顏色的測定方法-反射及透射物體顏色」而測定分光透射率且從色彩值(L*a*b*)求取。又，(L*a*b*)係在JIS Z 8729「顏色的表示方法-L*a*b*表色系及L*u*v*表色系」規定之物。L*為亮度，a*為紅色度，b*為黃色度。･Resistance to discoloration In order to measure the discoloration resistance of Cu balls, the Cu balls were heated at 200°C for 420 seconds using a constant temperature bath in the atmosphere, and the change in brightness was measured, and it was evaluated whether the Cu balls could sufficiently withstand changes over time. . The luminance is measured using a CM-3500d spectrophotometer manufactured by Konica Minolta under a D65 light source and a 10-degree field of view in accordance with JIS Z 8722 "Measurement of Color - Color of Reflected and Transmitted Objects" to measure the spectral transmittance and from the color value ( L*a*b*) to obtain. Also, (L*a*b*) is defined in JIS Z 8729 "Expression method of color-L*a*b* color system and L*u*v* color system". L* is lightness, a* is redness, b* is yellowness.
[耐變色性的評價基準] 在下述的各表，Cu球的耐變色性評價基準係如以下。 ○：420秒後的亮度為55以上 ×：420秒後的亮度為小於55。[Evaluation criteria for discoloration resistance] In each of the following tables, the discoloration resistance evaluation criteria of Cu balls are as follows. ○: Brightness after 420 seconds is 55 or higher x: The brightness after 420 seconds was less than 55.
･綜合評價 將在上述評價方法及評價基準之真球度、維氏硬度、α線量及耐變色性的任一者均為○或○○或○○○之Cu球，在綜合評價評定為○。另一方面，將在真球度、維氏硬度、α線量及耐變色性之中任一者為×之Cu球，在綜合評價評定為×。·Overview Cu balls that are ○ or ○○ or ○○○ in any one of the above-mentioned evaluation methods and evaluation criteria of true sphericity, Vickers hardness, α-ray content, and discoloration resistance are evaluated as ○ in the comprehensive evaluation. On the other hand, Cu balls that were x in any one of true sphericity, Vickers hardness, α ray content, and discoloration resistance were rated as x in the comprehensive evaluation.
又，將在上述評價方法及評價基準之真球度為○或○○或○○○之Cu核球，在與Cu球之評價一併之綜合評價評定為○。另一方面，將真球度為×之Cu核球，在綜合評價評定為×。又，即便在Cu核球的評價，真球度為○或○○或○○○，針對在Cu球的評價，真球度、維氏硬度、α線量及耐變色性之中任一者為×之Cu核球，係將綜合評價評定為×。In addition, Cu nuclei spheres whose true sphericity is ○ or ○○ or ○○○ in the above-mentioned evaluation method and evaluation standard were rated as ○ in the comprehensive evaluation together with the evaluation of Cu balls. On the other hand, the Cu nuclei whose true sphericity was X were evaluated as X in the comprehensive evaluation. Also, even if the true sphericity is ○ or ○○ or ○○○ in the evaluation of the Cu core ball, any one of the true sphericity, Vickers hardness, α-ray content, and discoloration resistance in the evaluation of the Cu ball is The Cu nuclei of × are rated as × in the comprehensive evaluation.
又，因為Cu核球的維氏硬度係依存於焊料層、及金屬層的一個例子之鍍Ni層，所以不評價Cu核球的維氏硬度。但是在Cu核球，Cu球的維氏硬度為在本發明規定範圍內時，Cu核球之耐落下衝擊性亦良好且能夠抑制龜裂而且亦能夠抑制電極塌陷等，而且亦能夠抑制導電性劣化。In addition, since the Vickers hardness of the Cu nuclei depends on the Ni plating layer which is an example of the solder layer and the metal layer, the Vickers hardness of the Cu nuclei was not evaluated. However, in the Cu core ball, when the Vickers hardness of the Cu ball is within the specified range of the present invention, the drop impact resistance of the Cu core ball is also good, cracks can be suppressed, electrode collapse, etc. can also be suppressed, and electrical conductivity can also be suppressed. deteriorating.
另一方面，在Cu核球之Cu球的維氏硬度為較大且超過本發明規定的範圍時，對來自外部的應力之耐久性變低且耐落下衝擊性變差之同時，有無法解決易產生龜裂之課題。On the other hand, when the Vickers hardness of the Cu ball of the Cu core ball is large and exceeds the range specified by the present invention, the durability against external stress becomes low and the drop impact resistance deteriorates, which cannot be solved. Problems prone to cracking.
因此，使用維氏硬度大於55.5HV之比較例8~11的Cu球之Cu核球，因為不適合維氏硬度的評價，所以將綜合評價評定為×。Therefore, the Cu core balls using the Cu balls of Comparative Examples 8 to 11 whose Vickers hardness was greater than 55.5 HV were not suitable for the evaluation of the Vickers hardness, so the overall evaluation was rated as x.
又，因為Cu核球的耐變色性係依存於焊料層、及金屬層的一個例子之鍍Ni層，所以Cu核球的耐變色性係不評價。但是Cu球的亮度為本發明規定的範圍內時，係能夠抑制Cu球表面的硫化物和硫氧化物且適合使用焊料層、鍍Ni層等的金屬層之被覆。In addition, since the discoloration resistance of the Cu nuclei depends on the Ni plating layer as an example of the solder layer and the metal layer, the discoloration resistance of the Cu nuclei was not evaluated. However, when the brightness of the Cu ball is within the range specified by the present invention, sulfide and oxysulfide on the surface of the Cu ball can be suppressed, and it is suitable to be coated with a metal layer such as a solder layer or a Ni plating layer.
另一方面，Cu球的亮度為低於本發明規定的範圍時，Cu球無法抑制表面的硫化物和硫氧化物且不適合使用焊料層、鍍Ni層等的金屬層之被覆。On the other hand, when the brightness of the Cu ball is lower than the range specified by the present invention, the Cu ball cannot suppress the sulfide and sulfur oxide on the surface, and it is not suitable for coating with a metal layer such as a solder layer or a Ni plating layer.
因此，使用420秒後的亮度為小於55之比較例1~6的Cu球之Cu核球，因為不適合耐變色性的評價，所以將綜合評價評定為×。Therefore, the Cu core balls using the Cu balls of Comparative Examples 1 to 6 whose luminance after 420 seconds were less than 55 were not suitable for the evaluation of discoloration resistance, so the overall evaluation was rated as x.
又，Cu核球的α線量係依存於構成被覆Cu球的焊料層之電鍍液原材料的組成、及組成中的各元素。設置被覆Cu球之金屬層的一個例子之鍍Ni層時，亦依存於構成Ni層之電鍍液原材料。In addition, the amount of α radiation of the Cu nuclei depends on the composition of the plating solution raw material constituting the solder layer covering the Cu balls, and each element in the composition. When the Ni plating layer, which is an example of the metal layer covering the Cu balls, is provided, it also depends on the raw material of the plating solution constituting the Ni layer.
Cu球係在本發明所規定的低α線量時，構成焊料層、及鍍Ni層之電鍍液原材料為本發明所規定的低α線量時，Cu核球亦成為本發明規定的低α線量。相對於此，構成焊料層、及鍍Ni層之電鍍液原材料為大於本發明所規定的α線量之高α線量時，即便Cu球為上述低α線量，Cu核球亦成為大於本發明規定的α線量之高α線量。When the Cu balls have the low α-ray content specified in the present invention, and when the raw materials of the electroplating solution constituting the solder layer and the Ni plating layer have the low α-line content specified in the present invention, the Cu core balls also have the low α-line content specified in the present invention. On the other hand, when the raw material of the plating solution constituting the solder layer and the Ni plating layer has a high α-ray content that is greater than the α-line content specified in the present invention, even if the Cu balls have the above-mentioned low α-line content, the Cu nuclei become larger than the α-line content specified in the present invention. High α ray content of α ray volume.
又，相較於本發明所規定的低α線量，構成焊料層、鍍Ni層之電鍍液原材料的α線量係顯示若干較高的α線量時，藉由在上述電鍍製程將不純物除去，而能夠減低至α線量為本發明所規定的低α線範圍為止。Also, when the α ray content of the plating solution raw materials constituting the solder layer and the Ni plating layer shows a somewhat higher α ray content than the low α ray content specified in the present invention, impurities can be removed by the above-mentioned electroplating process. Reduce until the amount of α-rays falls within the range of low α-rays specified in the present invention.
[表1]
[表2]
[表3]
[表4]
[表5]
[表6]
如表1顯示，4N5以上且5N5以下的純度之各實施例的Cu球，係任一者在綜合評價均能夠得到良好的結果。因此，Cu球的純度可說是以4N5以上且5N5以下為佳。As shown in Table 1, any of the Cu balls of the examples with a purity of 4N5 or more and 5N5 or less can obtain good results in the comprehensive evaluation. Therefore, the purity of Cu balls can be said to be above 4N5 and below 5N5.
以下，說明評價之詳細，如實施例1~12、18，純度為4N5以上且5N5以下，而且含有5.0質量ppm以上且50.0質量ppm以下的Fe、Ag或Ni之Cu球，係在真球度、維氏硬度、α線量及耐變色性的綜合評價能夠得到良好的結果。如實施例13~17、19顯示，純度4N5以上且5N5以下且合計含有5.0質量ppm以上且50.0質量ppm以下的Fe、Ag及Ni之Cu球，在真球度、維氏硬度、α線量及耐變色性的綜合評價亦能夠得到良好的結果。又，表中係未顯示，從實施例1、18、19各自將Fe的含量變更成為0質量ppm以上且小於5.0質量ppm、將Ag的含量變更成為0ppm以上且小於5.0質量ppm、將Ni的含量變更成為0質量ppm以上且小於5.0質量ppm且將Fe、Ag及Ni的合計設為5.0質量ppm以上之Cu球，在真球度、維氏硬度、α線量及耐變色性的綜合評價亦能夠得到良好的結果。The details of the evaluation will be described below. As in Examples 1 to 12 and 18, Cu balls with a purity of 4N5 or more and 5N5 or less, and containing Fe, Ag, or Ni of 5.0 mass ppm or more and 50.0 mass ppm or less are based on the true sphericity. , Vickers hardness, α-ray content and comprehensive evaluation of discoloration resistance can get good results. As shown in Examples 13 to 17 and 19, Cu balls with a purity of 4N5 or more and 5N5 or less and a total of Fe, Ag, and Ni containing 5.0 mass ppm or more and 50.0 mass ppm or less have good sphericity, Vickers hardness, α ray content, and The comprehensive evaluation of discoloration resistance also yielded favorable results. Also, not shown in the table, from Examples 1, 18, and 19, the content of Fe was changed from 0 ppm to less than 5.0 ppm by mass, the content of Ag was changed from 0 ppm to less than 5.0 ppm by mass, and the content of Ni was changed to Cu balls whose content is changed from 0 mass ppm to less than 5.0 mass ppm and whose total content of Fe, Ag, and Ni is 5.0 mass ppm or more are also good in the comprehensive evaluation of true sphericity, Vickers hardness, α ray content, and discoloration resistance. able to get good results.
又，如實施例18顯示，含有5.0質量ppm以上且50.0質量ppm以下的Fe、Ag或Ni且其它不純物元素的Sb、Bi、Zn、Al、As、Cd、Pb、In、Sn、Au為各自50.0質量ppm以下之實施例18的Cu球，在真球度、維氏硬度、α線量及耐變色性的綜合評價亦能夠得到良好的結果。Also, as shown in Example 18, Sb, Bi, Zn, Al, As, Cd, Pb, In, Sn, and Au containing Fe, Ag, or Ni and other impurity elements from 5.0 mass ppm to 50.0 mass ppm are each The Cu balls of Example 18 with 50.0 mass ppm or less can also obtain good results in the comprehensive evaluation of true sphericity, Vickers hardness, α-ray content, and discoloration resistance.
針對Cu核球，係如表3、表4顯示，藉由使用含有0.7質量%的Cu且剩餘部分為Sn之組成例1的焊料合金之焊料層，被覆實施例1~實施例19的Cu球而成之實施例1A~19A的Cu核球；及使用鍍Ni層被覆實施例1~實施例19的Cu球，進而藉由使用組成例1的焊料合金之焊料層被覆而成之實施例1B~19B的Cu核球，在真球度的綜合評價亦能夠得到良好的結果。For Cu core balls, as shown in Table 3 and Table 4, the Cu balls of Examples 1 to 19 were coated with the solder layer of the solder alloy of Example 1 containing 0.7% by mass of Cu and the remainder being Sn. The resulting Cu core balls of Examples 1A to 19A; and Example 1B formed by coating the Cu balls of Examples 1 to 19 with a Ni-plated layer and then covering them with a solder layer of the solder alloy of Example 1 The comprehensive evaluation of true sphericity of ~19B Cu nuclei can also get good results.
藉由使用含有3.0質量%的Cu且剩餘部分為Sn之組成例2的焊料合金之焊料層，被覆實施例1~實施例19的Cu球而成之實施例1A~19A的Cu核球；及使用鍍Ni層被覆實施例1~實施例19的Cu球，進而藉由使用組成例2的焊料合金之焊料層被覆而成之實施例1B~19B的Cu核球，在真球度的綜合評價亦能夠得到良好的結果。The Cu core balls of Examples 1A to 19A formed by coating the Cu balls of Examples 1 to 19 with the solder layer of the solder alloy of Composition Example 2 containing 3.0% by mass of Cu and the remainder being Sn; and Comprehensive evaluation of the true sphericity of the Cu balls of Examples 1 to 19 coated with a Ni-plated layer, and the Cu nuclei of Examples 1B to 19B coated with the solder layer of the solder alloy of Example 2 Good results can also be obtained.
又，在表中未顯示，從實施例1、18、19各自將Fe的含量變更成為0質量ppm以上且小於5.0質量ppm、將Ag的含量變更成為0質量ppm以上且小於5.0質量ppm、將Ni的含量變更成為0質量ppm以上且小於5.0質量ppm且將Fe、Ag及Ni的合計設為5.0質量ppm以上之Cu球，藉由使用組成例1~組成例2之任一者的焊料合金之焊料層被覆而成之Cu核球，而且使用鍍Ni層被覆該Cu球，進而藉由使用組成例1~組成例2之任一者的焊料合金之焊料層被覆而成之Cu核球，在真球度的綜合評價亦能夠得到良好的結果。Also, not shown in the table, from Examples 1, 18, and 19, the Fe content was changed from 0 mass ppm to less than 5.0 mass ppm, the Ag content was changed from 0 mass ppm to less than 5.0 mass ppm, and The content of Ni is changed to be 0 mass ppm or more and less than 5.0 mass ppm and the total of Fe, Ag, and Ni is 5.0 mass ppm or more of Cu balls, by using any one of the solder alloy of composition example 1 to composition example 2 The Cu core ball formed by coating the solder layer, and the Cu ball is coated with a Ni-plated layer, and the Cu core ball formed by coating the solder layer of the solder alloy of composition example 1 to composition example 2, Good results can also be obtained in the comprehensive evaluation of true sphericity.
另一方面，比較例7的Cu球，不但Fe、Ag及Ni的含量的合計不滿5.0質量ppm，且U、Tu未滿5質量ppb，其他的雜質元素亦未滿1質量ppm，比較例7的Cu球，將比較例7的Cu球，以各組成例的焊料合金的焊料層覆蓋的比較例7A的Cu核球、及將比較例7的Cu球以鍍Ni層覆蓋，進一步以各組成例的焊料合金的焊料層覆蓋的比較例7B的Cu核球，球度均未達到0.95。又，即便含有不純物元素，Fe、Ag及Ni之中至少1種的含量合計未達到5.0質量ppm之比較例12的Cu球、將比較例12的Cu球藉由使用各組成例的焊料合金之焊料層被覆而成之比較例12A的Cu核球、及使用鍍Ni層被覆比較例12的Cu球，進而藉由使用各組成例的焊料合金之焊料層被覆而成之比較例12B的Cu核球，真球度未達到0.95。從該等結果，Fe、Ag及Ni之中至少1種的含量合計未達到5.0質量ppm之Cu球、將該Cu球藉由使用各組成例的焊料合金之焊料層被覆而成之Cu核球、及將該Cu球使用鍍Ni層被覆，進而藉由使用各組成例的焊料合金之焊料層被覆而成之Cu核球可說是無法實現高真球度。On the other hand, in the Cu ball of Comparative Example 7, not only the total content of Fe, Ag, and Ni was less than 5.0 mass ppm, but also U and Tu were less than 5 mass ppm, and other impurity elements were less than 1 mass ppm. The Cu ball of Comparative Example 7, the Cu core ball of Comparative Example 7A covered with the solder layer of the solder alloy of each composition example, and the Cu ball of Comparative Example 7 covered with a Ni plating layer, and further prepared with each composition None of the Cu core spheres of Comparative Example 7B covered with the solder layer of the solder alloy of Example had a sphericity of 0.95. In addition, the Cu balls of Comparative Example 12 whose total content of at least one of Fe, Ag, and Ni did not reach 5.0 mass ppm even if impurity elements were contained, and the Cu balls of Comparative Example 12 were mixed by using solder alloys of the respective composition examples. The Cu core ball of Comparative Example 12A coated with a solder layer, and the Cu core ball of Comparative Example 12B coated with a solder layer using a solder alloy of each composition example by coating the Cu ball of Comparative Example 12 with a Ni plating layer The true sphericity of the ball does not reach 0.95. From these results, Cu balls in which the total content of at least one of Fe, Ag, and Ni is less than 5.0 mass ppm, and Cu core balls in which the Cu balls are coated with a solder layer using a solder alloy of each composition example , and Cu core balls formed by coating the Cu balls with a Ni-plated layer and further coating with the solder layer of the solder alloy of each composition example cannot achieve high true sphericity.
又，比較例10的Cu球係Fe、Ag及Ni的含量合計為153.6質量ppm且其它不純物元素的含量為各自50質量ppm以下，但是維氏硬度為大於55.5HV而無法得到良好的結果。而且，比較例8的Cu球不僅是Fe、Ag及Ni的含量合計為150.0質量ppm，而且其它不純物元素的含量亦特別是Sn為151.0質量ppm，大幅度地大於50.0質量ppm且維氏硬度為大於55.5HV而無法得到良好的結果。因此，即便純度為4N5以上且5N5以下的Cu球，Fe、Ag及Ni之中至少1種的含量合計大於50.0質量ppm之Cu球係維氏硬度為變大且可說是無法實現低硬度。如此，Cu球的維氏硬度係大於本發明規定的範圍時，對來自外部的應力之耐久性變低且耐落下衝擊性變差之同時，亦無法解決容易產生龜裂之課題。而且，可說是各自在不超過50.0質量ppm的範圍含有其它不純物元素為佳。Also, in Comparative Example 10, the Cu spherical Fe, Ag, and Ni contents were 153.6 mass ppm in total and the contents of other impurity elements were each 50 mass ppm or less, but the Vickers hardness was greater than 55.5 HV and good results could not be obtained. Furthermore, in the Cu ball of Comparative Example 8, not only the total content of Fe, Ag, and Ni is 150.0 mass ppm, but also the content of other impurity elements, especially Sn, is 151.0 mass ppm, which is significantly greater than 50.0 mass ppm, and the Vickers hardness is Greater than 55.5HV does not give good results. Therefore, even for Cu balls with a purity of 4N5 or more and 5N5 or less, the Vickers hardness of Cu balls with a total content of at least one of Fe, Ag, and Ni greater than 50.0 mass ppm increases and low hardness cannot be achieved. In this way, when the Vickers hardness of the Cu ball exceeds the range specified by the present invention, the durability against external stress decreases, the drop impact resistance deteriorates, and the problem that cracks are likely to occur cannot be solved. Furthermore, it can be said that it is preferable to contain other impurity elements within a range of not more than 50.0 mass ppm each.
從該等結果，純度為4N5以上且5N5以下而且含有Fe、Ag及Ni之中至少1種的含量合計為5.0質量ppm以上且50.0質量ppm以下之Cu球，可說是能夠實現高真球度及低硬度且抑制變色。藉由使用各組成例的焊料合金之焊料層被覆此種Cu球而成之Cu核球、使用鍍Ni層被覆此種Cu球，進而藉由使用各組成例的焊料合金之焊料層被覆而成之Cu核球係實現高真球度，而且藉由實現Cu球為低硬度，作為Cu核球，耐落下衝擊性亦良好且能夠抑制龜裂而且亦能夠抑制電極塌陷等，進而亦能夠抑制導電性劣化。而且，藉由能夠抑制Cu球變色而適合於使用焊料層、鍍Ni層等的金屬層之被覆。其它不純物元素的含量係各自以50.0質量ppm以下為佳。From these results, it can be said that Cu balls with a purity of 4N5 or more and 5N5 or less and a total content of at least one of Fe, Ag, and Ni of 5.0 mass ppm or more and 50.0 mass ppm or less can achieve high sphericity And low hardness and inhibit discoloration. Cu core balls formed by coating such Cu balls with a solder layer of a solder alloy of each composition example, coating such a Cu ball with a Ni-plated layer, and coating with a solder layer of a solder alloy of each composition example The Cu core ball system achieves high true sphericity, and by realizing the low hardness of the Cu ball, as the Cu core ball, the drop impact resistance is also good, cracks can be suppressed, and electrode collapse can also be suppressed, which in turn can also suppress electrical conduction. sexual deterioration. Furthermore, since discoloration of Cu balls can be suppressed, it is suitable for covering with metal layers such as a solder layer and a Ni plating layer. The content of other impurity elements is preferably 50.0 mass ppm or less.
在表中未顯示，與該等實施例相同組成且球徑為1μm以上且1000μm以下的Cu球，係任一者在真球度、維氏硬度、α線量及耐變色性的綜合評價均能夠得到良好的結果。因此，Cu球的球徑可說是以1μm以上且1000μm以下為佳，以50μm以上且300μm以下為較佳。Not shown in the table, Cu balls having the same composition as those of the examples and having a ball diameter of not less than 1 μm and not more than 1000 μm can be evaluated in terms of true sphericity, Vickers hardness, α ray content, and discoloration resistance. get good results. Therefore, it can be said that the diameter of the Cu ball is preferably not less than 1 μm and not more than 1000 μm, and is more preferably not less than 50 μm and not more than 300 μm.
實施例19的Cu球，係Fe、Ag及Ni的含量合計為5.0質量ppm以上且50.0質量ppm以下且含有2.9質量ppm的P，在真球度、維氏硬度、α線量及耐變色性的綜合評價能夠得到良好的結果。將實施例19的Cu球藉由使用各組成例的焊料合金之焊料層被覆而成之Cu核球、實施例19的Cu球使用鍍Ni層被覆，進而藉由使用各組成例的焊料合金之焊料層被覆而成之Cu核球，在真球度的綜合評價均得到良好的結果。比較例11的Cu球係Fe、Ag及Ni的含量合計係與實施例19的Cu球同樣地為50.0質量ppm以下，但是維氏硬度為大於5.5HV而成為與實施例19的Cu球不同的結果。又，比較例9之維氏硬度亦大於5.5HV。認為這是因為比較例9、11的P含量為顯著地較多，從該結果，得知P的含量為增加時，維氏硬度變大。因此，P的含量可說是以小於3質量ppm為佳，以小於1質量ppm為較佳。The Cu ball of Example 19 has a total content of Fe, Ag, and Ni of not less than 5.0 mass ppm and not more than 50.0 mass ppm and contains 2.9 mass ppm of P. A comprehensive evaluation can yield good results. The Cu balls of Example 19 were coated with a solder layer using the solder alloy of each composition example. The Cu balls of Example 19 were coated with a Ni plating layer, and then by using The comprehensive evaluation of the true sphericity of the Cu nuclei spheres covered by the solder layer has obtained good results. The total content of Fe, Ag, and Ni in the Cu ball system of Comparative Example 11 is 50.0 mass ppm or less as in the Cu ball of Example 19, but the Vickers hardness is greater than 5.5HV, which is different from the Cu ball of Example 19. result. In addition, the Vickers hardness of Comparative Example 9 is also greater than 5.5HV. This is considered to be because the P content in Comparative Examples 9 and 11 was remarkably high, and from this result, it can be seen that when the P content increases, the Vickers hardness increases. Therefore, it can be said that the content of P is preferably less than 3 mass ppm, more preferably less than 1 mass ppm.
在各實施例的Cu球，α線量為0.0200cph/cm2 以下。因此在被覆各實施例1~19的Cu球之組成例1及組成例2的焊料合金，藉由各元素為本發明規定的低α線量，各實施例1A~19A的Cu核球亦成為本發明規定的低α線量。又，設置有被覆Cu球之金屬層的一個例子之鍍Ni層時，係除了焊料合金以外，藉由構成鍍Ni層之各元素為本發明規定的低α線量，各實施例1B~19B的Cu核球亦成為本發明規定的低α線量。In the Cu balls of each example, the amount of α rays was 0.0200 cph/cm 2 or less. Therefore, in the solder alloys of Composition Example 1 and Composition Example 2 that cover the Cu balls of Examples 1 to 19, the Cu core balls of Examples 1A to 19A also become the present invention because each element has a low α radiation content specified in the present invention. The amount of low alpha rays specified by the invention. Also, when the Ni plating layer as an example of the metal layer covered with Cu balls is provided, in addition to the solder alloy, each element constituting the Ni plating layer has a low α dose specified by the present invention, and each of Examples 1B to 19B The Cu nuclei also become the low α ray amount specified in the present invention.
而且，藉由在形成焊料層、鍍Ni層之電鍍的製程，將在合金所含有之放射α線的不純物除去，即便相較於本發明規定的低α線量，電鍍前的合金之α線量係顯示若干較高的α線量時，電鍍後的α線量亦能夠減低至本發明規定的低α線量範圍為止。Moreover, through the electroplating process for forming the solder layer and the Ni plating layer, the impurities that emit α rays contained in the alloy are removed. When showing some higher α-ray dose, the α-ray dose after electroplating can also be reduced to the low α-ray dose range specified by the present invention.
藉此，將各實施例的Cu核球使用在電子零件的高密度封裝時，藉由構成焊料層、鍍Ni層之電鍍液原材料為本發明規定的低α線量，能夠抑制軟錯誤。Therefore, when the Cu nuclei of each embodiment are used in high-density packaging of electronic components, soft errors can be suppressed by using the low α-ray content as the raw material of the plating solution constituting the solder layer and the Ni plating layer as specified in the present invention.
在比較例7的Cu球，在耐變色性能夠得到良好的結果，另一方面，在比較例1~6係在耐變色性係無法得到良好的結果。將比較例1~6的Cu球與比較例7的Cu球進行比較時，該等組成的差異係只有S的含量。因此為了在耐變色性得到良好的結果，可說是必須使S的含量成為小於1質量ppm。從各實施例的Cu球係任一者之S的含量均小於1質量ppm，亦可說是S的含量係以小於1質量ppm為佳。In the Cu ball of Comparative Example 7, good results in discoloration resistance were obtained, but in Comparative Examples 1 to 6, favorable results were not obtained in discoloration resistance. When comparing the Cu balls of Comparative Examples 1-6 with the Cu balls of Comparative Example 7, the difference in the composition is only the content of S. Therefore, in order to obtain good results in discoloration resistance, it can be said that the S content must be less than 1 mass ppm. The S content of any of the Cu spheres in each embodiment is less than 1 mass ppm, and it can be said that the S content is preferably less than 1 mass ppm.
接著，為了確認S的含量與耐變色性之關係，係將實施例14、比較例1及比較例5的Cu球在200℃加熱，而且拍攝加熱前、加熱60秒後、180秒後、420秒後的照片且測定亮度。表7及第5圖係將加熱各Cu球之時間與亮度的關係製成圖表。Next, in order to confirm the relationship between the S content and the discoloration resistance, the Cu balls of Example 14, Comparative Example 1, and Comparative Example 5 were heated at 200°C, and photographed before heating, after heating for 60 seconds, after 180 seconds, and 420 Seconds later the photo is taken and the brightness is measured. Table 7 and Fig. 5 are graphs of the relationship between the time for heating each Cu ball and the brightness.
[表7]
從該表，將加熱前的亮度與加熱420秒後的亮度進行比較時，實施例14、比較例1、5的亮度係在加熱前為接近64和65附近之值。在加熱420秒後，含有30.0質量ppm的S之比較例5的亮度變為最低，接著為含有10.0質量ppm的S之比較例1、及S的含量為小於1質量ppm的實施例14之順序。因此，可說是S的含量為越多，加熱後的亮度越低。比較例1、5的Cu球，因為亮度小於55，所以含有10.0質量ppm以上的S之Cu球，在加熱時形成硫化物和硫氧化物而可說是容易變色。又，S的含量為0質量ppm以上且1.0質量ppm以下時，能夠抑制硫化物和硫氧化物的形成且可說是濕潤性良好。又，將實施例14的Cu球封裝在電極上時係顯示良好的濕潤性。From the table, when the brightness before heating is compared with the brightness after heating for 420 seconds, the brightness of Example 14, Comparative Examples 1 and 5 are values close to 64 and 65 before heating. After heating for 420 seconds, the brightness of Comparative Example 5 containing 30.0 mass ppm of S became the lowest, followed by Comparative Example 1 containing 10.0 mass ppm of S, and Example 14 in which the S content was less than 1 mass ppm. . Therefore, it can be said that the higher the S content, the lower the brightness after heating. The Cu balls of Comparative Examples 1 and 5 have brightness less than 55, so Cu balls containing 10.0 mass ppm or more of S tend to change color by forming sulfide and sulfur oxide when heated. Moreover, when the content of S is 0 mass ppm or more and 1.0 mass ppm or less, the formation of sulfide and sulfur oxide can be suppressed, and it can be said that the wettability is good. Also, when the Cu ball of Example 14 was packaged on the electrode, it showed good wettability.
如以上，純度為4N5以上且5N5以下，Fe、Ag及Ni之中至少1種的含量合計為5.0質量ppm以上且50.0質量ppm以下，S的含量為0質量ppm以上且1.0質量ppm以下，P的含量為0質量ppm以上且小於3.0質量ppm之本實施例的Cu球，因為任一者的真球度均為0.95以上，所以能夠實現高真球度。藉由實現高真球度，將Cu球封裝在電極等時能夠確保自對準性之同時，能夠抑制Cu球高度的偏差。使用焊料層被覆本實施例的Cu球而成之Cu核球；及使用金屬層被覆本實施例的Cu球，進而使用焊料層被覆金屬層而成之Cu核球均能夠得到同樣的效果。As above, the purity is not less than 4N5 and not more than 5N5, the total content of at least one of Fe, Ag, and Ni is not less than 5.0 mass ppm and not more than 50.0 mass ppm, the content of S is not less than 0 mass ppm and not more than 1.0 mass ppm, P The Cu balls of the present example whose Cu content is 0 mass ppm or more and less than 3.0 mass ppm can realize high sphericity because all of them have a true sphericity of 0.95 or greater. By achieving a high degree of sphericity, it is possible to suppress variation in the height of the Cu ball while ensuring self-alignment when the Cu ball is packaged in an electrode or the like. The same effect can be obtained by using the Cu core ball formed by coating the Cu ball of this embodiment with a solder layer; and the Cu core ball formed by coating the Cu ball of this embodiment with a metal layer and further coating the metal layer with a solder layer.
又，因為本實施例的Cu球係任一者之維氏硬度均為55HV以下，所以能夠實現低硬度。藉由實現低硬度，能夠提升Cu球的耐落下衝擊性。藉由實現Cu球為低硬度，使用焊料層被覆本實施例的Cu球而成之Cu核球；及使用金屬層被覆本實施例的Cu球，進而使用焊料層被覆金屬層而成之Cu核球，耐落下衝擊性均良好且能夠抑制龜裂，而且亦能夠抑制電極塌陷等且亦能夠抑制導電性劣化。In addition, since the Vickers hardness of any of the Cu ball systems of this example is 55 HV or less, low hardness can be realized. By achieving low hardness, the drop impact resistance of Cu balls can be improved. By realizing the low hardness of the Cu ball, use the Cu core ball formed by covering the Cu ball of this embodiment with a solder layer; and cover the Cu ball of this embodiment with a metal layer, and then use the Cu core formed by covering the metal layer with a solder layer The balls had good drop impact resistance and suppressed cracking, and also suppressed electrode collapse and the like, and also suppressed deterioration in electrical conductivity.
而且，本實施例的Cu球係任一者均能夠抑制變色。藉由能夠抑制Cu球變色，能夠抑制硫化物和硫氧化物對Cu球造成不良影響之同時，將Cu球封裝在電極上時的濕潤性提升。藉由能夠抑制Cu球變色而適合使用焊料層、鍍Ni層等的金屬層之被覆。Furthermore, any of the Cu balls of this example can suppress discoloration. By suppressing discoloration of the Cu balls, it is possible to suppress adverse effects of sulfides and sulfur oxides on the Cu balls, and improve wettability when the Cu balls are encapsulated on the electrodes. Since discoloration of Cu balls can be suppressed, it is suitable for coating of metal layers such as solder layer and Ni plating layer.
又，本實施例的Cu材係使用純度為大於4N5且6N以下的Cu塊狀金屬材，而製造純度為4N5以上且5N5以下的Cu球，但是即便使用大於4N5且6N以下的金屬線材、板材等，在Cu球、Cu核球的雙方在綜合評價亦能夠得到良好的結果。In addition, the Cu material of this embodiment uses a Cu bulk metal material with a purity greater than 4N5 and less than 6N to manufacture Cu balls with a purity of more than 4N5 and less than 5N5. etc. Good results were also obtained in the comprehensive evaluation of both Cu balls and Cu core balls.
在Cu球1的表面，使用將Cu的含量設為大於0質量%且3.0質量%以下、剩餘部分設為Sn且不含有Ag的組成之焊料合金形成焊料層3而成之Cu核球11A、11B，係即便接合對象物為經對Cu層表面施行預助焊劑處理而成之Cu-OSP基板，即便為經對Cu層表面施行電解Ni/Au電鍍而成之電解Ni/Au電鍍基板，對落下等的衝擊之強度、及對被稱為熱循環之溫度變化引起伸縮之強度均能夠得到被認為必要的預定強度。On the surface of the
使用不含有Ag之焊料合金所製造的焊球，係相較於使用含有Ag之焊料合金所製造的焊球，對熱循環之強度降低。在各實施例的Cu核球11A、11B，雖然使用不含有Ag之焊料合金形成焊料層3，相較於使用含有Ag之焊料合金所製造的Cu核球，除了能夠得到被認為必要的落下強度以外，對熱循環之強度提升。Solder balls fabricated using solder alloys that do not contain Ag are less resistant to thermal cycling than solder balls fabricated using solder alloys that contain Ag. In the
其次，說明在藉由使用Sn系的焊料合金之焊料層被覆Cu球的表面而成之Cu核球，在焊料層中Sn以外的元素之分布。作為被覆Cu球之焊料層，係如日本特開2007-44718號公報(稱為專利文獻4)、日本特許第5367924號公報(稱為專利文獻5)顯示，能夠使用將Sn作為主成分之焊料合金。Next, the distribution of elements other than Sn in the solder layer of Cu nuclei balls formed by coating the surface of Cu balls with a solder layer using a Sn-based solder alloy will be described. As the solder layer covering the Cu balls, as shown in JP-A-2007-44718 (referred to as Patent Document 4) and JP-A No. 5367924 (referred to as Patent Document 5), solder containing Sn as a main component can be used. alloy.
在專利文獻4，係使用由Sn及Bi所構成的Sn系焊料合金被覆Cu球的表面而形成焊料層。含有Bi之Sn系焊料合金，其熔融溫度為130~140℃之較低溫且被稱為低溫焊料。In Patent Document 4, a Sn-based solder alloy composed of Sn and Bi is used to coat the surface of Cu balls to form a solder layer. The Sn-based solder alloy containing Bi has a relatively low melting temperature of 130-140°C and is called a low-temperature solder.
在專利文獻4，係以在焊料層中所含有的Bi之含量為內側(內周側)較淡、朝向外側(外周側)而變濃之濃度梯度被電鍍處理。In Patent Document 4, the content of Bi contained in the solder layer is electroplated with a concentration gradient such that the content of Bi contained in the solder layer is lighter on the inner side (inner peripheral side) and becomes richer toward the outer side (outer peripheral side).
在專利文獻5，亦揭示一種將由Sn及Bi所構成的Sn系焊料合金進行電鍍被膜在Cu球而成之焊料凸塊。在專利文獻5，係以焊料層中所含有的Bi之含量為內側(內周側)較濃、朝向外側(外周側)變淡之濃度梯度被電鍍處理。Patent Document 5 also discloses a solder bump in which Cu balls are plated with a Sn-based solder alloy composed of Sn and Bi. In Patent Document 5, the content of Bi contained in the solder layer is plated with a concentration gradient such that the content of Bi contained in the solder layer is richer on the inner side (inner peripheral side) and becomes lighter toward the outer side (outer peripheral side).
專利文獻5的技術係與專利文獻4為完全相反的濃度梯度。認為這是因為依照專利文獻5之濃度控制係比依照專利文獻4時較簡單且容易製造。The technique of Patent Document 5 is a completely opposite concentration gradient to that of Patent Document 4. This is considered to be because the concentration control according to Patent Document 5 is simpler and easier to manufacture than that according to Patent Document 4.
如上述，將在Sn添加有其它元素之二元以上的Sn系焊料合金電鍍被膜Cu球的表面而成之Cu核球，載置在半導體晶片的電極上而進行回流處理時，所添加的元素係在焊料層中具有濃度梯度之專利文獻4及5係引起如以下的問題。As mentioned above, when the Cu nuclei formed by electroplating the surface of Cu balls coated with a Sn-based solder alloy containing binary or more elements added to Sn are placed on the electrodes of the semiconductor wafer and subjected to reflow treatment, the added elements Patent Documents 4 and 5, which have a concentration gradient in the solder layer, cause problems as follows.
在專利文獻4所揭示的技術係具有Bi濃度為在內周側較淡、在外周側變濃的濃度梯度之焊料層，此種濃度梯度(內側較淡、外側較濃)時，Bi熔融的時序在內周側與外周側有少許產生偏移之可能性。The technique disclosed in Patent Document 4 has a solder layer with a concentration gradient in which the Bi concentration is lighter on the inner peripheral side and thicker on the outer peripheral side, and Bi is melted in such a concentration gradient (lighter on the inner side and thicker on the outer side). There is a slight possibility that the timing may deviate between the inner peripheral side and the outer peripheral side.
在熔融時序產生偏移時，係成為Cu核球的外表面開始熔融，而內周面側的區域為尚未產生熔融之部分熔解摻雜的情形，其結果在核材料熔融之側產生少許位置偏移。狹窄間距的高密度封裝時，由於該位置偏移致使焊接處理有致命性的缺陷之可能性。When the melting sequence is shifted, the outer surface of the Cu nuclei starts to melt, and the region on the inner peripheral surface side is partially melted and doped. shift. In the case of high-density packaging with narrow pitches, there is a possibility of a fatal defect in the soldering process due to the positional deviation.
專利文獻5之Bi的濃度梯度係與專利文獻1相反。此時為了將半導體組件連接，係進行藉由回流之加熱處理。如專利文獻5，在焊料層中的Bi濃度為內周側為較濃、外周側較淡的狀態下進行加熱熔融時，因為內周側的Bi密度較高，所以焊料從內周側的Bi區域開始熔融。因為內周側的Bi區域熔融，而外周側的Bi區域尚未開始熔融，所以在內周側的Bi區域側較快速地產生體積膨脹。The concentration gradient of Bi in Patent Document 5 is opposite to that in
由於該體積膨脹在內外周側的快慢，而在Bi的內周側與外周側(外氣)產生壓力差，Bi的外周側開始熔融時，內周側的體積膨脹引起的壓力差致使成為核之Cu球產生如迸飛之事態。此種事態的產生必須避免。Due to the speed of this volume expansion on the inner and outer peripheral sides, a pressure difference is generated between the inner peripheral side and the outer peripheral side (outside air) of Bi, and when the outer peripheral side of Bi starts to melt, the pressure difference caused by the volume expansion on the inner peripheral side becomes a nucleus. The thick ball produces a state of affairs such as flying. Such a situation must be avoided.
如此，具有由Sn及Bi所構成的Sn系焊料合金所構成的焊料層之Cu核球，在焊料層中的Bi具有濃度梯度時，係產生不良。In this way, the Cu nuclei ball having a solder layer composed of a Sn-based solder alloy composed of Sn and Bi causes defects when Bi in the solder layer has a concentration gradient.
通常使用在Sn添加有Cu之二元以上的焊料合金被覆核而成之核材料，Cu在焊料層中具有預定濃度梯度時，亦被認為與上述Bi產生同樣的問題。Generally, a core material obtained by coating a binary or higher solder alloy in which Sn is added to Cu is used. When Cu has a predetermined concentration gradient in the solder layer, it is considered that the same problem as that of the above-mentioned Bi occurs.
因此，說明接著焊料層3中的Cu的分布為均勻之作用效果。為了確認在焊料層3之Cu的濃度分布為與目標值相稱之值，係進行如以下的實驗。
(1)在下述條件下製造焊料層3的組成為(Sn-0.7Cu)之Cu核球11B。在以下的實施例，係使用表1顯示之實施例17的組成之Cu球。
･Cu球1的直徑：250μm
･金屬層(鍍Ni層)2的膜厚：2μm
･焊料層3的膜厚：23μm
･Cu核球11B的直徑：300μmTherefore, the effect that the distribution of Cu in the
為了使用實驗結果的測定容易化，作為Cu核球11B，係製造具有厚度較薄的焊料層之Cu核球。In order to facilitate measurement using experimental results, Cu nuclei balls having a thinner solder layer were produced as
電鍍方法係藉由電鍍技術而製造。
(2)準備10個形成有相同組成的(Sn-0.7Cu)系焊料合金的焊料層之Cu核球11B作為試料。使用該等作為試料A。
(3)使用樹脂將10個試料A密封。
(4)經密封後的各試料A連樹脂一起研磨且觀察各試料A的剖面。觀察機件係使用日本電子製的FE-EPMAJXA-8530F。The electroplating method is manufactured by electroplating technology.
(2) Ten
第6圖係顯示測定Cu核球的Cu的濃度分布之方法的一個例子之說明圖。焊料層3之中，從Cu球1的表面側起為了方便而區分成為內層16a、中間層16b及外層16c。內層16a係從Cu球1的表面起至9μm為止，中間層16b係至9~17μm為止，而且外層16c係設為17~23μm，從內層16a、中間層16b及外層16c，如第6圖在該例子係各自切取厚度5μm且寬度為40μm的內層區域17a、中間層區域17b、外層區域17c，將各區域作為計量區域，藉由定性分析而進行計量Cu的濃度。合計10視野針對各自各內層16a、中間層16及外層16c進行該作業。Fig. 6 is an explanatory diagram showing an example of a method of measuring the concentration distribution of Cu in the Cu nuclei. The
將計量焊料層的內層、中間層、外層的Cu濃度而求取之各層的濃度比率顯示在以下的表8。The concentration ratio of each layer obtained by measuring the Cu concentration of the inner layer, the middle layer, and the outer layer of the solder layer is shown in Table 8 below.
表8係在試料A，顯示在各自10個的Cu核球所計量的焊料層之各層的Cu濃度的平均值、及作為目標之Cu含量(目標值)為0.7質量%時之Cu的濃度比率。Table 8 shows the average value of Cu concentration in each layer of the solder layer measured by 10 Cu core balls in Sample A, and the Cu concentration ratio when the target Cu content (target value) is 0.7% by mass .
試料A係如上述，針對各自10個Cu核球，計量內層、中間層、外層的Cu濃度。針對試料A，係未將10個Cu核球各自在內層、中間層、外層之Cu濃度的計量值顯示在表8。As for the sample A, the concentrations of Cu in the inner layer, the middle layer, and the outer layer were measured for each of the 10 Cu core spheres as described above. For sample A, Table 8 does not show measured values of Cu concentrations in the inner layer, middle layer, and outer layer of the 10 Cu core spheres.
試料A之目標Cu含量(目標值)為0.7質量%。此時，在試料A之10個Cu核球各自Cu的濃度比率(%)係從Cu的濃度計量值且藉由以下的(1)式而求取。 濃度比率(%)=(計量值/0.7)×100･･･(1)The target Cu content (target value) of the sample A was 0.7 mass %. At this time, the concentration ratio (%) of Cu in each of the 10 Cu core spheres of the sample A was obtained from the measured value of the concentration of Cu by the following formula (1). Concentration ratio (%)=(measurement value/0.7)×100･･･(1)
又，Cu的濃度之平均值係作為試料之Cu核球的數目為10個時，能夠藉由以下的(2)式而求取。 Cu的濃度之平均值=10個計量值的合計值/10･･･(2)In addition, the average value of the Cu concentration can be obtained by the following formula (2) when the number of Cu nuclei spheres used as a sample is 10. Average value of Cu concentration = total value of 10 measured values/10･･･(2)
而且，作為目標之Cu的含量(目標值)為0.7質量%時，試料A的濃度比率(%)係能夠從Cu的濃度的計量值之平均值且藉由以下的(3)式而求取。 濃度比率(%)=(計量值的平均值/0.7)×100･･･(3)Furthermore, when the target Cu content (target value) is 0.7% by mass, the concentration ratio (%) of the sample A can be obtained from the average value of the measured values of the Cu concentration by the following formula (3) . Concentration ratio (%)=(average value of measured value/0.7)×100･･･(3)
[表8]
如表8顯示，針對試料A，在內層區域17a之Cu的濃度之平均值為值為0.58質量%、濃度比率82.9%，在中間層區域17b之Cu的濃度之平均值為0.68質量%、濃度比率97.1%，在外層區域17c之Cu的濃度之平均值為0.51質量%、濃度比率72.9%。As shown in Table 8, for sample A, the average value of the concentration of Cu in the inner layer region 17a is 0.58% by mass and the concentration ratio is 82.9%, and the average value of the concentration of Cu in the
如此，在內層區域17a、中間層區域17b、外層區域17c之各自，因為焊料層中的Sb濃度係在上述0.51質量%~0.68質量%的容許範圍內，濃度比率為72.9~97.1%，大約落入目標值的Cu濃度比率亦即70~130%。Thus, for each of the inner layer region 17a, the
而且，從與該等試料A同批次製造的Cu核球各自抽出例如10個，將各自藉由通常的回流處理而接合在基板。接合結果亦一併顯示在表8。Then, for example, 10 Cu core spheres produced in the same batch as the sample A were extracted, and each was bonded to a substrate by a normal reflow process. The joining results are also shown in Table 8.
針對接合結果，將在全部試樣全部均未測定到接合不良之物判定為「良」。Regarding the joining results, those in which no joint failure was measured in all the samples were judged as "good".
任一者均不產生以下的事態：內周側比外周側快速地熔融且內周側與外周側產生體積膨脹差致使Cu核球11B產生迸飛之事態，而且因為焊料層3全體為大致均勻地熔融且因為不產生被認為因熔融時序的偏移而產生之核材料的位置偏移，所以沒有伴隨著位置偏移等而電極間產生短路等之可能性。因此，因為完全未發生接合不良且能夠得到良好的結果而判定為「良」。In either case, the inner peripheral side melts faster than the outer peripheral side and the volume expansion difference between the inner peripheral side and the outer peripheral side causes the Cu nuclei 11B to fly away, and the
如上述，(Sn-0.7Cu)系焊料合金時，從表8的結果，得知0.51質量%(濃度比率72.9%)~0.68質量%(濃度比率97.1%)的範圍為止為能夠容許的範圍。As mentioned above, in the case of (Sn-0.7Cu) based solder alloys, the results in Table 8 show that the range of 0.51 mass % (concentration ratio 72.9%) to 0.68 mass % (concentration ratio 97.1%) is an acceptable range.
其次，針對形成由(Sn-3Cu)所構成的Sn系焊料合金之焊料層3時亦進行同樣的計量。此時Cu的分布係3質量%作為目標值，作為容許範圍係2.45質量%(濃度比率81.7%)~3.26質量%(濃度比率108.7%)。Cu核球的製造方法，係與採用上述使用(Sn-0.7Cu)的焊料合金之Cu核球作為試料A的實施例時相同。Next, the same measurement was performed also when forming the
針對所使用的Cu球及Cu核球的直徑、金屬層(鍍Ni層)及焊料層的膜厚等的規格、及實驗條件，係除了焊料層的組成以外，係與試料A相同條件。The specifications of the diameters of the Cu balls and Cu core balls used, the film thicknesses of the metal layer (Ni plating layer) and the solder layer, and the experimental conditions are the same as those of the sample A except for the composition of the solder layer.
將其結果，以表8的試料B之方式顯示。此時因為目標值之Cu為3質量%，如試料試料B顯示，為2.45~3.26質量%(任一者均是針對同一試料計量10次之平均值)，雖然多少具有偏差(平均值的最小2.45質量%(濃度比率81.7%)~最大3.26質量%(濃度比率108.7%))之程度，但是在容許範圍。因而，得知落入2.45質量%(濃度比率81.7%)~3.26質量%(濃度比率108.7%%)。接合判定係與試料A的實施例相同，因為能夠得到完全不產生接合不良之良好的結果所以判定為「良」。The results are shown in the form of sample B in Table 8. At this time, because the Cu of the target value is 3% by mass, as shown in sample B, it is 2.45~3.26% by mass (both of which are the average value measured 10 times for the same sample), although there is some deviation (the minimum value of the average value 2.45 mass % (concentration ratio 81.7%) ~ maximum 3.26 mass % (concentration ratio 108.7%)), but within the allowable range. Therefore, it is found that it falls within 2.45% by mass (81.7% concentration ratio) to 3.26% by mass (108.7%% concentration ratio). The joining judgment system was the same as that of the example of sample A, and since good results were obtained in which no joint failure occurred at all, it was judged as "good".
試料B係作為目標之Cu的含量(目標值)為3(質量%)。因此，表8中試料B的濃度比率(%)係能夠藉由以下的(4)式而求取。In the sample B, the content (target value) of Cu made into a target was 3 (mass %). Therefore, the concentration ratio (%) of the sample B in Table 8 can be obtained by the following formula (4).
濃度比率(%)=(計量值的平均值/3)×100･･･(4) 將上述試料A的實施例、試料B的實施例之結果彙總在表9。Cu的濃度比率為72.9%~108.7質量%。在此，針對試料A的實施例、試料B的實施例製成之Cu核球測定真球度時任一者均為0.99以上且滿足0.95以上。Concentration ratio (%)=(average value of measured value/3)×100･･･(4) Table 9 summarizes the results of the Examples of Sample A and Sample B described above. The concentration ratio of Cu is 72.9% to 108.7% by mass. Here, when the true sphericity of the Cu nuclei produced in the example of sample A and the example of sample B is measured, any of them is 0.99 or more and satisfies 0.95 or more.
[表9]
表9中的濃度比率(%)係能夠藉由以下的(5)式而求取。 濃度比率(%)=(計量值/目標值)×100･･･(5)The concentration ratio (%) in Table 9 can be obtained by the following formula (5). Concentration ratio (%)=(measurement value/target value)×100･･･(5)
又，焊料層3內的Cu濃度改變時，係有產生位置偏移、Cu核球11B被吹離等之現象。Also, when the concentration of Cu in the
如以上說明，在各實施例A、B，因為焊料層中的Cu為均質，所以相對於焊料層的膜厚，Cu在包含內周側、外周側之全區域範圍的Cu濃度比率為預定範圍內。因此，焊料層中的Cu為均質之本發明的Cu核球係不產生如以下之事態：內周側比外周側快速地熔融且內周側與外周側產生體積膨脹差致使Cu核球產生迸飛之事態。As described above, in each of Examples A and B, since Cu in the solder layer is homogeneous, the Cu concentration ratio of Cu in the entire area including the inner peripheral side and the outer peripheral side with respect to the film thickness of the solder layer is within a predetermined range. Inside. Therefore, the Cu nuclei sphere system of the present invention in which the Cu in the solder layer is homogeneous does not produce such a situation that the inner peripheral side melts faster than the outer peripheral side and the volume expansion difference between the inner peripheral side and the outer peripheral side causes the Cu nuclei spheres to burst. The flying situation.
又，因為焊料層中的Cu為均質，Cu核球的全面範圍大致均勻地熔融之緣故，所以焊料層內熔融時序幾乎不產生時間差。其結果，因為不產生熔融時序的偏移而引起之Cu核球的位置偏移，所以沒有伴隨著位置偏移等而在電極間產生短路等之可能性。因而，藉由使用該Cu核球而能夠提供高品質的焊接頭。In addition, since Cu in the solder layer is homogeneous and the Cu nuclei are melted almost uniformly over the entire area, there is almost no time difference in the melting sequence in the solder layer. As a result, since there is no displacement of the Cu nuclei due to the displacement of the melting sequence, there is no possibility of causing a short circuit between the electrodes due to the displacement or the like. Therefore, a high-quality solder joint can be provided by using the Cu nuclei.
1‧‧‧Cu球
11A、11B‧‧‧Cu核球
2‧‧‧金屬層
3‧‧‧焊料層
10‧‧‧半導體晶片
16a‧‧‧內層區域
16b‧‧‧中間層區域
16c‧‧‧外層區域
17a‧‧‧內層區域
17b‧‧‧中間層區域
17c‧‧‧外層區域
100、41‧‧‧電極
30‧‧‧焊料凸塊
40‧‧‧印刷基板
50‧‧‧焊接頭
60‧‧‧電子零件
1‧‧‧
第1圖係顯示本發明之第1實施形態的Cu核球之圖。 Fig. 1 is a diagram showing Cu nuclei according to the first embodiment of the present invention.
第2圖係顯示本發明之第2實施形態的Cu核球之圖。 第3圖係顯示本發明之各實施形態之使用Cu核球的電子零件的構成例之圖。 第4圖係Cu核球的放大剖面圖。 第5圖係顯示將實施例及比較例的Cu球在200℃加熱後之加熱時間與亮度的關係之圖表。 第6圖係顯示測定Cu核球的Cu的濃度分布之方法的一個例子之說明圖。 Fig. 2 is a diagram showing a Cu core sphere according to a second embodiment of the present invention. Fig. 3 is a diagram showing a configuration example of an electronic component using Cu core balls according to each embodiment of the present invention. Fig. 4 is an enlarged cross-sectional view of a Cu nuclei sphere. Fig. 5 is a graph showing the relationship between the heating time and the brightness after heating the Cu balls of Examples and Comparative Examples at 200°C. Fig. 6 is an explanatory diagram showing an example of a method of measuring the concentration distribution of Cu in the Cu nuclei.
1‧‧‧Cu球 1‧‧‧Cube ball
3‧‧‧焊料層 3‧‧‧Solder layer
11A‧‧‧Cu核球 11A‧‧‧Cu core
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| JP2018111877A JP6572997B1 (en) | 2018-06-12 | 2018-06-12 | Cu core ball, solder joint, solder paste and foam solder |
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|---|---|---|---|---|
| TW201537710A (en) * | 2013-11-05 | 2015-10-01 | Senju Metal Industry Co | Cu core ball, solder paste, formed solder, Cu core column, and solder joint |
| TW201540395A (en) * | 2014-01-28 | 2015-11-01 | Senju Metal Industry Co | Cu core ball, solder paste and solder joint |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW201537710A (en) * | 2013-11-05 | 2015-10-01 | Senju Metal Industry Co | Cu core ball, solder paste, formed solder, Cu core column, and solder joint |
| TW201540395A (en) * | 2014-01-28 | 2015-11-01 | Senju Metal Industry Co | Cu core ball, solder paste and solder joint |
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| JP6572997B1 (en) | 2019-09-11 |
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