TWI334366B - - Google Patents

Description

1334366 IX. INSTRUCTIONS OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to solder balls used for soldering of surface-mount components, and in particular to solder-free solder balls without Pb. [Prior Art] A surface-mounted component is a structure in which an electronic component is directly soldered on a land formed on a surface of a printed substrate. Generally, there are QFP, PLCC, SOP, SOJ, and the like. When the surface component is mounted on a printed circuit board, a solder paste is applied to the pad of the printed substrate, and the surface component is loaded on the coating portion, and the solder paste is melted in a welding furnace. This solders the surface mount component to the printed substrate. The above-mentioned surface-constructed parts are somewhat multi-functional. Due to the miniaturization and multi-function of electronic machines in recent years, surface-constructed parts are also required to be smaller and more highly functional. Nowadays, BGA (ball grid) Array, Ba] Grid Arrey), CSP (Chip Size Package), ΤΑβ (Tape Automated Bonding), MCM (Multi Chip Module) and other multi-functional surface mounts Parts (hereinafter, represented by BGA) are widely used. When the BGA is mounted on a printed substrate, a solder bump is formed on the Α electrode in advance, and the solder bump is used for soldering on the printed substrate. Here, a solder bump is formed on the electrode of the BGA. First, an adhesive solder and a solder paste are applied to the BGA electrode, and the solder ball is loaded on the coating portion by a loading device. Thereafter, the solder ball is heated by the BGA heated by the soldering furnace to melt the solder ball. A solder bump is formed on the electrode of the BGA. 5 1334366 Since the soldering temperature at this time is at least higher than the temperature of the ball (4), c is above, and the surface of the solder ball which is hostile is easily oxidized. _ When the printed circuit board is mounted on the printed circuit board, the solder paste is applied to the solder pads of the printed circuit board, and the coated portion is placed in alignment with the BGA bumps. Then, the furnace is again deheated to make the tan paste The solder bumps are melted to solder the BGA to the printed substrate. The conventional BGA is based on a 30x30nira β (the formation of 15〇~25〇 electrodes on the germanium substrate 'because the distance between adjacent electrodes is H—) The Tan ball used in this example can be used. The .76 has a larger diameter. However, in recent years, as the electronic device has been miniaturized, the BGA has become smaller, and the solder balls used in the miniaturized BGA have become smaller. For example, 'in i〇 400 electrodes are formed in the BGA of xi〇(mm), and the distance between adjacent electrodes is less than 咖5. The solder ball of such a narrow pitch BGA becomes very small with a diameter of less than mm·3mm. In the past, the solder ball used in the BGA was a Sn_pb solder. The sn_pb φ solder is a eutectic composition (63Sn-pb), has good solderability, and has few defects, so it is widely used. However, when used If the electronic equipment containing lead solder balls becomes old and has poor usability or malfunction, it will not be directly discarded if it is upgraded or repaired. When the electronic equipment is discarded, the plastic or metal reusables that constitute the electronic equipment will be recovered. However, since the solder joint on the printed circuit board is metallically adhered to the solder and cannot be completely separated, it cannot be reused even if it is recycled, and it has to be disposed of by burying. Therefore, if the printed substrate containing the buried substrate is in contact with acid rain, the solder is soldered. P in the middle The b component will be dissolved and mixed with the acid rain into the groundwater. If the human or livestock drink the Pb into 6 ° ^ 366 for a long time, the Pb component will be accumulated in the body and cause poisoning of the ship. Therefore, Pb has been restricted in the world. ❹, and the system does not have a solder containing no pb. The so-called lead-free solder is Sn-Ag-based, Sn-Cu-based, Sn-Ag-Cu-based, Sn-Sb-based, Sn-Bi-based, Sn-Zn-based, and Sn-based. Further, other additives are added to these materials. Although the lead-free materials are various alloys as described above, they each have advantages and disadvantages, and are used depending on the application. In the Sn-B! lead-free solder, Sn_58Bi has a very low melting point of 139 ° C. Therefore, it has the advantage of making electronic parts less affected by heat. However, since it is very brittle, its use is limited. Further, in the Sn_Zn system, since the melting point of Sn_9Zn is 1.990C', which is similar to the smear of the eutectic solder of the previous 63Sn_pb, it is a solder which is easy to handle at a temperature, but the tendency of Zn ionization is large, so corrosion resistance is obtained. The problem of insufficient sex. Sn_3·5Ag (melting point 22〇.〇, 〇.7Cu (melting point 227〇C), Sn-3Ag-〇.5Cu (melting point 217°C), Sn-4Sb (melting_point 240. 〇, etc. with Sn as the main component The error-free tan material is mostly used for soldering of electronic machines because it has a slightly higher melting point than the eutectic solder and has high mechanical strength. In particular, it is often used to form bumps in the BGA in the shape of solder balls. As an additive element of lead-free solder. In order to lower the melting point, I η or Bi may be added; p, Ge, and Ga may be added for the purpose of oxidation resistance; in order to improve the mechanical strength, 1 core may be added, wherein Patent Document 6 discloses that the addition of Cr is error-free. Japanese Patent Application Laid-Open No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. However, in the above-mentioned BGA electrode, the lead-free solder ball having the above-mentioned eight + Λ as a main component is used to form a V-based electrode: When the fcp material is bumped, the surface of the bump block will have a yellow (yellow) change.

That is, the solder on the BGA. The formation of the block, after the solder ball is loaded on the BGa electrode (4), the soldering towel is placed on the BGA edge. X Ping 坺 is melted, and after yellow and solder bumps are formed during melting, the image is discriminated by the image. #胃# i Μ Λ ^上τ 用 Use the home to determine the presence or absence of BGA t 卞4 bumps. If the solder bumps are yellowed at this time, the image recognition device may generate an error. ~ Like the use of Sn as the main component of the ::: harsh conditions, for example, in the streets of exhaust gas = exhaust gas will enter the electrical control device; or in the home near the beach home Machine|ξ or 雷哭田σ Machine stealing electricity, the air containing salt water will enter the interior of L. In such a ball-free ball, if the tan joint is exposed to the atmosphere of the exhaust gas or salt, the zen material will be rotted and the crack will be peeled off or peeled off after 4 years. . In order to improve the joint strength, Sn4 r is carried out as described above, and second:::: welding defects may occur. According to the present invention, when the embossing bump is formed, the surface of the bump does not only violently rot in the environment of the rot, so that it is not easy to rot, nor does it? / From the Tan is not 8 good. Not inventors, etc., for the reason of solder = :::: when forming solder bumps on the bump etch, and rot in the residual atmosphere... As a result of efforts, the solder bumps turn yellow, and the #焊料表Jinzhi. That is, the solder must be rolled during the welding to understand the fish Ph ft AA, and then melt, when molten. The oxide of Pb will be covered on the surface of the Sn_pb solder Pb ^ ^ ^ D bad village. Since the Sn and the emulsion 3 Pb are slightly white, there is no shortage of defects; for the image recognition device... However, for the error-free solder containing Sn as a main component, the Sn of the main component of the melting Oxidation, which can cause errors in the image recognition device. ...the coloring of the 'coloring', the corrosion of the ambient atmosphere makes the welding part of the profit, the household due to the main component of the lead-free solder ball, and the rot (four) ring two / the second is not recorded... . , the ring-sex is more than the previous 63Sn_Pb: : This 'the inventor's attention to: as long as the surface is not easy to oxidize the state called Bu Ke + by the ear branch, w and as long as the welding pile 诒, on the knowing surface has Panguang Mingshi Maidan ς ★ The shielding of the clothing atmosphere barrier, even if it contains Da Liru, is not easy to rot. When the present invention has an element of a large shielding effect, it is proposed to install [" knowing. The anti-oxidation of the sea and the addition of a very small amount of t Cr in the middle can be presented as a non-new solder cost invention of "#". There is anti-rolling and shielding effect, and according to the inventor, hemp, day, in In the case of itch (4), the oxidation of Cr/: the presence of a heart in the solder alloy prevents the film from covering the surface of the cut material, and the contact of the rusted silver atmosphere. The result is that the surface of the material is not oxidized and emulsified. The present invention is not limited to corrosion. The present invention is a kind of L-sports rhododendron ^ complex 4... 钇 球 ball' which contains 80% by mass or more of Sn, which is characterized in that it is in the solder ball Adding 0. 0001~0. 003% by mass of Cr. Since the non-recording solder ball of the present invention is formed in the case of a Heilongjiang and a solder bump formed on the BGA, the image recognition device is used. ^ a ^ 罝 仃 像 像 像 像 像 像 像 像 像 像 像 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆 铓祆The ring & nipple will not corrode, so it will not erode the crack or peeling of the solder itself, but it can be fully Since the σ degree is good, the testability and the reliability are good. [Embodiment] The lead-free solder ball of the present invention, Q Λ 糸 is in the Sn-Ag system, the Sn-Cu system,

Both the Sn-Ag-Cu system and the Sn-Sb system in the body i κ system can be used as such, and the pleats are provided in the "double fruit, in the 曰 。. 糸 糸" means the alloy In itself, or in the alloy, six elements are placed in other elements. For example, what is it... Adding less in gold - Yuanren What is known as - 竑, refers to Sn_ - 兀 alloy, and P, Γ ... g in Sn_A. 4 is added from In, Bi, Sb, Ni,

Ge, Ga is one of the group consisting of ^, s ς 之

The Lu-based Sn-Sb system is also the result of the change of the solder. That is, when s... is wide because of the addition of a large amount of additions a: more than 80% of the quality of the syllabus. After the change, it will become a lot of τ ‘ 溶%% 氧 氧 氧 丄 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像 影像Therefore, the present invention is <the purpose is to taste C human & u f yellow. η 3 is set to be more than 8% by mass of the error-free solder. The invention is based on the above-mentioned φ 士, 〇. .003 mass kCr, if the C 2 is not added to the mass of the material, then the profit method is added. The amount of addition is less than 0._ The effect of preventing yellowing and preventing the money is increased. If 10 is added, it exceeds 0. 003. The oxide film is too thick to deteriorate the weldability. In the present invention, the Cr addition amount is preferably from 0. 0005 to 0.001% by mass. The error-free solder ball of the present invention will have a weak joint strength against the influence of the corrupted money. #直徨〇·〇5~〇. 6mm has an excellent effect.

In the following, the examples and comparative examples are shown in Table 1. Express

Vapor change: After placing the ball of 0.3 mm diameter in the high temperature bath of 15 °c, observe the color of the surface visually. The surface of the solder ball is not "excellent", but the image is slightly yellowed, but the image recognition device is not faulty. "Good", the image recognition device produces a degree of discoloration, which is not good, and is not good. : A solder ball with a diameter of 33mm is placed on the BGA electrode (diameter • 25mm) and heated by a soldering furnace to form solder bumps on the electrode. This = solder adheres to the entire area of the electrode as "excellent", almost Attached to the entire area of the electrode and the end is somewhat unattached, good, most of the unattached 1334366 is "poor,". This month's lead-free solder ball is suitable for forming BGA bumps, but Of course, it is also applicable to the formation of bumps other than 11BGA, such as forming bumps on the top of the top pin or forming bumps on the electrodes of the connector. [Simplified description of the figure] Benefits [Main component symbol description]

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Claims (1)

1 003质量%的Cr。 Adding 0. 003质量质量的Cr。 The solder ball is added to the 0.00. 0. 003 mass% of Cr. I 001质量%的范围内。 I 2. The range of the 0.001 mass% of the range of 0. 0005~0. 001 mass%. 3. For the lead-free solder ball of the first or second patent application, it is any one of a Sn-Ag system, a Sn-Cu system, a Sn-Ag-Cu system, and a Sn-Sb system. 4. For the lead-free solder balls of the first or second patent application, the diameter is 0.005~0.6mm. Η—, pattern: none 13