JP2007284096A - Electronic device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device that makes it unnecessary for a purchaser to take measure to protect against whiskers, and to provide a manufacturing method for the electronic device. <P>SOLUTION: An electronic device coated with a lead-free solder film is packaged in a packaging material. The electronic device is washed before packaged. Information such as "washed" or "cleaned" is shown on the electronic device or the packaging material. The manufacturing method includes the steps of forming a solder film of a lead-free solder on the electronic device, the step of washing the electronic device after the formation of the film, the step of packaging the electronic device after the process of washing, and the step of displaying information such as "washed" or "cleaned" on the electronic device or the packaging material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device in which a solder film of lead-free solder is formed and packed with a packing material, and a method for manufacturing the same, and more particularly to an electronic device in which a purchaser does not need to take measures against whiskers and a method for manufacturing the same.

  Electronic devices are manufactured by mounting electronic components such as semiconductor devices, resistors, capacitors, and sockets on a printed circuit board. For example, in the case of a semiconductor device, after packaging a chip, external leads are solder-mounted on a printed circuit board. A solder film is formed on the surface of the external lead.

  In recent years, lead-free solder has been promoted to prevent environmental pollution. However, when lead-free solder is used as the solder coating, whiskers tend to occur more easily than when lead-containing solder is used. In general, it is said that whisker is caused by internal stress, but the details are not well understood.

The following have been proposed as countermeasures against whiskers.
(1) Use a matte plating bath. This is because when a bright plating bath is used, a brightener is contained in the solder coating and the formation of crystal grains becomes irregular and whiskers are likely to occur.
(2) An iron-based material is used as a base. This is because if a copper-based material is used as the base, whiskers are easily generated due to the formation of a tin intermetallic compound.
(3) The solder film thickness is set to 8 μm or more which is not easily affected by interface mismatch. This is because if the plating thickness is small, the base lattice and the solder coating lattice are mismatched at the interface, and whiskers are likely to occur.
(4) A heat treatment of the solder coating is performed. As a result, the compressive stress in the solder coating is relieved and whiskers are hardly generated.

Japanese Patent No. 3115565 Japanese Patent No. 3187399

  There was a problem that whiskers were generated even when the above whisker measures were taken. On the other hand, the inventor has found that the occurrence of whiskers can be suppressed by cleaning the electronic device to remove contaminants adhering to the solder coating. Thus, if the electronic device is cleaned and then packed and sold, the purchaser does not need to take measures against whiskers.

  However, if the purchaser is not informed that “cleaned” or “cleaning measures have been taken”, the purchaser again takes unnecessary whisker measures. The moisture-proof display is disclosed in, for example, Patent Documents 1 and 2, but it is not proposed to display that whisker countermeasures have been taken.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain an electronic device that does not require a purchaser to take countermeasures against whiskers and a method for manufacturing the same.

  An electronic device according to the present invention is an electronic device in which a solder coating of lead-free solder is formed and packed with a packing material, the electronic device is washed before packing, and the electronic device or the packing material has a whisker countermeasure The information regarding “washed” or “cleaning countermeasures completed” is displayed.

  In addition, a method for manufacturing an electronic device according to the present invention includes a film forming process for forming a solder film of lead-free solder on an electronic device, a cleaning process for cleaning the electronic device after the film forming process, and an electronic device after the cleaning process. And a step of displaying information on “cleaned” or “cleaning countermeasures completed” on the electronic device or the packing material. Other features of the present invention will become apparent below.

  According to the present invention, it is not necessary for a purchaser who has purchased an electronic device to take measures against whiskers.

  The present invention relates to an electronic device packed with a packing material and a method for manufacturing the same. Here, a case where a semiconductor device is used as the electronic device will be described.

  FIG. 1 is a partially cutaway perspective view showing an example of a semiconductor device, and FIG. 2 is a sectional view thereof. The semiconductor device 10 is a surface mounting package called FPP (Flat Plastic Package) or QFP (Quad Flat Package).

  In the semiconductor device 10, the semiconductor chip 11 is fixed on the island 13 via the Ag paste 12. An Al pad 14 is formed on the semiconductor chip 11. An Ag plating 16 is formed on the inner end of the lead 15. The inner end of the lead 15 and the Al pad 14 are wire bonded by a gold wire 17. These structures are transfer molded with a mold resin 18.

  A solder coating 19 is formed by plating on the leads 15 (external leads) protruding from the mold resin 18 of the semiconductor device 10. Here, the lead 15 is made of copper or Fe—Ni alloy, and the solder coating 19 is made of lead-free solder such as Sn—Ag, Sn—Bi, Su—Cu, or pure Sn.

  Here, if contaminants adhere to the solder coating 19, it is considered that the oxidation of the surface of the solder coating 19 proceeds in a short time, and internal stress is generated by volume expansion accompanying the oxidation, thereby promoting the generation of whiskers. In particular, when the film thickness of the solder coating 19 is 20 μm or less, whisker growth becomes significant. Therefore, the semiconductor device 10 is washed to remove contaminants attached to the solder coating 19. Thereby, generation | occurrence | production of a whisker can be suppressed.

  As pollutants, although not clear at present, anions such as halogens, sulfur, phosphorus, and nitrogen are considered. In addition, cleaning methods include water cleaning, ion cleaning, chemical cleaning, and neutralization, but water cleaning is particularly effective. Further, if cleaning is performed before the electronic devices are separated, a plurality of electronic devices can be cleaned at a time, so that the manufacturing process can be simplified.

  After cleaning, the semiconductor device 10 is packed with a packing material. Here, the magazine 21 shown in FIG. 3, the interior box 22 shown in FIG. 4, and the bag body 23 shown in FIG. 5 are used as packing materials. First, as shown in FIG. 6, a plurality of semiconductor devices 10 are packed in a magazine 21, and a stopper 24 is attached to the end of the magazine 21 in order to prevent the semiconductor device 10 from protruding outside the magazine. Then, the magazine 21 is stored in a paper-made interior box 22.

Next, as shown in FIG. 7, the interior box 22 is placed in the bag body 23, and after deaeration, the opening 25 of the bag body 23 is heat-sealed. And the information regarding "washing completed" or "cleaning countermeasure completed" of implementing the whisker countermeasure is displayed on the surface of the bag body 23. Specifically, the information is printed on the surface of the bag body 23 or a label 26 on which the information is written is attached. Further, the information may be displayed on the surface of the interior box 22 or the magazine 21, or the information may be displayed on the semiconductor device 10 itself. The information may be a specific numerical value of “chlorine ion contamination amount: 100 ng / cm ² or less”. In addition, “CCW” mark can be displayed on the main body of an electronic device that cannot display characters by abbreviating “Clean Components against Whisker”.

  Thereby, it can be communicated to the purchaser who has purchased the electronic device that the occurrence of whiskers has been prevented. Therefore, a purchaser who has purchased an electronic device can be distinguished from an electronic device that does not prevent the occurrence of whiskers, and does not need to take another whisker countermeasure. Therefore, the product value can be increased and the manufacturer can be differentiated.

  Here, it is preferable to indicate that the electronic device or the packaging material is a lead-free device. In addition, write information on “washed” or “cleaned” in any of electronic component manuals, catalogs, pamphlets, technical documents, contracts, and delivery specifications, and pack it together with electronic equipment using packing materials. Is preferred. It is also possible to transmit in advance information related to the “cleaned” or “cleaning countermeasures completed” via a transmission medium such as broadcasting or the Internet.

  In the above embodiment, the case where a semiconductor device is used as the electronic device has been described. However, not only semiconductor devices, but other electronic components such as resistors and capacitors, printed circuit boards (including semi-finished products), and other electronic components mounted on printed circuit boards have other lead-free solder coatings. The present invention can also be applied to an electronic device.

  Further, the solder coating is not limited to a solder coating formed by plating, and various solder materials containing tin, such as a solder coating formed by coating and solder used for solder mounting, are targeted.

  Moreover, the tray 31 shown in FIG. 8 can also be used as a packing material. The tray 31 is made of vinyl chloride that has been subjected to antistatic treatment, and the semiconductor device 10 is placed in a rectangular recess 32 that is arranged in an array. The trays 31 are stacked and accommodated in the interior box 22, and then hermetically sealed in the bag body 23. Further, as a packing material, a tape and reel system shown in FIG. 9 can be used. The semiconductor devices 10 are held in a row via an adhesive tape 35 on a carrier tape 34 wound around a reel 33. The reels 33 are hermetically sealed into the bag body 23 one reel at a time. In this case, information regarding “washed” or “cleaning countermeasures completed” is displayed on the tray 31, the reel 33, or the carrier tape 34.

It is a partially cutaway perspective view showing an example of a semiconductor device. It is sectional drawing which shows an example of a semiconductor device. It is a perspective view which shows a magazine. It is a perspective view which shows an interior box. It is a perspective view which shows a bag body. It is sectional drawing which shows the state which packed the semiconductor device in the magazine. It is a perspective view which shows the electronic device which concerns on embodiment of this invention. It is a perspective view which shows a tray. It is a perspective view which shows a tape & reel system.

Explanation of symbols

10 Semiconductor devices (electronic devices)
19 Solder coating 21 Magazine (packaging body)
22 Inner box (packaging body)
23 Bag (Packaging)
26 Label 31 Tray (Packaging body)
33 reel
34 Carrier tape (packaging body)

Claims (11)

An electronic device in which a solder film of lead-free solder is formed and packed with a packing material,
The electronic device is cleaned before packing,
The electronic apparatus or the packing material is displayed with information on “washed” or “cleaning countermeasure completed” indicating that whisker countermeasures are being implemented.   The electronic device according to claim 1, wherein the electronic device or the packing material also indicates that it is a lead-free device.   The electronic component manual, catalog, pamphlet, technical data, contract, or delivery specification in which information on the “cleaned” or “cleaning countermeasures” is described is further provided. 3. The electronic device according to 2.   The electronic device according to claim 1, wherein the electronic device is washed with water before packaging.   5. The electronic device according to claim 1, wherein the solder film has a thickness of 20 μm or less. A film forming process for forming a lead-free solder film on the electronic device;
A cleaning step of cleaning the electronic device after the film formation step;
Packing the electronic device with a packing material after the cleaning step;
And a step of displaying information related to “washed” or “cleaning countermeasure completed” indicating that the electronic device or the packing material is subjected to whisker countermeasures.   The method of manufacturing an electronic device according to claim 6, further comprising a step of displaying on the electronic device or the packaging material that the device is a lead-free device.   Describe information on the “cleaned” or “cleaned” in electronic manuals, catalogs, pamphlets, technical documents, contracts, or delivery specifications, and pack it with the packing material together with the electronic device, The electronic device according to claim 6, further comprising a step of transmitting information related to the “cleaned” or “cleaning countermeasure completed” via a transmission medium such as broadcast or the Internet. Production method.   The method for manufacturing an electronic device according to claim 6, wherein in the cleaning step, the electronic device is cleaned with water.   The method for manufacturing an electronic device according to claim 6, wherein the cleaning step is performed before the electronic device is singulated. 11. The method of manufacturing an electronic device according to claim 6, wherein the film thickness of the solder coating is 20 μm or less in the film forming step.

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