JP2011114334A - Solder coat film forming method and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device that solves a problem of overvolume of a very narrow pitch part etc., and further reduces economical inefficiency accompanying frequent disposal of deteriorated solder by preventing impurities such as flux and copper oxide from being mixed and accumulated over time in a molten solder liquid circulating jet type automatic soldering device and method. <P>SOLUTION: After a solder coat is formed on an electrode pad or a lead surface of an electronic component 5 by jetting an organic fatty acid solution 8 and molten solder 1 from nozzles 4 and 14, the organic fatty acid solution and molten solder which overflow are sent to a stirrer 9 to strongly stir and mix them in the stirrer, the copper oxide, flux components and reaction products thereof, oxidation impurities, etc., mixed in the overflowing solution are taken into the organic fatty acid solution, and the molten solder is purified and reused to prevent copper from being accumulated in the molten solder liquid, thereby continuously performing stable soldering for a long period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

In particular, the present invention forms tin or a solder film on electrode pads or leads of a semiconductor wafer, a semiconductor chip, an interposer (wiring board), a semiconductor device, a mounting board (hereinafter referred to as an electronic circuit board) or an electronic component. And a method thereof.
More specifically, a method and apparatus for spraying molten tin or a molten solder alloy onto an electrode pad or lead surface of an electronic circuit board or electronic component to form (join) a tin or solder film, and molten tin circulating from a storage tank in the apparatus Alternatively, the present invention relates to a technique and an apparatus for preventing copper oxide and flux components from being dissolved as impurities in a solder alloy solution and increasing the copper concentration and impurity concentration over time.

In recent years, electronic devices are increasingly required to be highly reliable and small and light. Electronic devices such as transistors, diodes, ICs, resistors and capacitors, electronic components such as connectors, and printed circuit boards can be joined with tin or solder. Electronic circuits are formed and widely used as semiconductor devices and electronic devices, but with the miniaturization of these electronic elements, electronic components, and printed circuit boards, solder joints are also miniaturized, resulting in higher quality reliability. It is requested. In particular, extremely strict reliability is required for the quality of the fine solder joint between the electronic circuit board and the electronic element component.
For this reason, the tin or solder alloy side used for tin or solder bonding also has high bonding strength, especially high reliability of the tin or solder micro-joint due to miniaturization of the bonding area and pitch of the electrode pads or leads of electronic devices and electronic components. Sex is required.
On the other hand, in recent years, the use of lead has been banned or regulated due to environmental pollution and harm to the human body, and so-called “lead-free solder alloys” that do not contain lead are widely used for soldering, especially in the field of electronic components. In particular, tin / silver / copper solder alloys and solder alloys with antimony added thereto (patent document 1), tin / silver / copper solder alloys with nickel or germanium added, etc. (patent document) 2) etc. are proposed and put into practical use. In addition to these, a number of various solder alloys have been proposed, such as a tin / zinc / nickel solder alloy and a solder alloy further added with silver, copper, bismuth, etc. (Patent Document 3).
In general, as a method of forming (joining) a tin or solder alloy film on the surface of an electrode pad or lead part of an electronic component such as a printed circuit board, a semiconductor package, or an electronic element, the tin or solder alloy has a melting point or higher in a storage tank. After heating to temperature and melting to form a liquid, the tin or solder alloy solution is jetted from a nozzle or slit and sprayed onto an electrode pad or lead of an electronic circuit board or electronic component, and then tin or solder. The overflow is returned to the original storage tank for circulation, but the flux and copper oxide film, etc. present on the electrode pad or lead surface during soldering are contained in the overflow of the molten tin or molten solder alloy liquid. The copper concentration and impurity concentration in the molten tin or molten solder alloy liquid mixed in as impurities become higher over time, the solder composition changes, and the physical properties The chemical properties also change, especially the solder wettability worsens, so that the solder rises at the joint with more capacity than necessary, so-called "over volume" (horn, tsura), and in the circuit where the pitch between leads is narrow, it bridges to the adjacent lead In addition to the difficulty of over-leakage, there is also the difficulty of causing external phenomena such as solder unattachment (Patent Document 4). In addition, since the elongation, which is one of the physical and mechanical characteristics of the solder joint, is reduced, it is incorporated into a semiconductor device or the like as an electronic circuit and then repeatedly energized on-off. Thus, it is widely known that poor conduction or the like is likely to occur and the connection reliability of a miniaturized electronic device is impaired. Therefore, after the continuous soldering process, if the copper concentration exceeds a certain upper limit and the above-mentioned solder characteristics deteriorate and an abnormal phenomenon (quality defect) occurs, in general, the deteriorated solder is discarded relatively frequently and the solder is renewed. Therefore, it is extremely inefficient from the viewpoint of resources, workability and quality stability, and economically.
For this reason, in particular, as a method of suppressing the increase in copper concentration during continuous processing of printed circuit boards and the like and improving efficiency, when the molten solder solution in the liquid storage tank drops to a certain level during continuous processing, A method of replenishing the second solder mainly composed of the removed alloy has been proposed and put into practical use, but even with this method, the increase in copper can be suppressed to some extent, but the tendency to increase over time does not change. Although the solder joint quality tends to deteriorate with time, there is a problem of preparing and managing the second solder, and there is a merit of extending the service life, but it is not always a satisfactory method. (Patent Document 4)
JP 5-50286 (Patent 3027441) JP 11-77366 (Patent 3296289) Japanese Patent Laid-Open No. 9-94688 (Patent 3299091) JP2001-237536 (Patent 3216709)

  The present invention prevents contamination and accumulation of impurities such as flux and copper oxide in a tin or solder alloy solution over time in a molten tin or molten solder solution circulating jet automatic soldering apparatus and method currently in practical use. As a result, the above-mentioned problem of over-volume (thorn, tsura), which is a difficult point when joining small tin or solder such as micro-leads and very narrow lead-pitch circuits, leakage from adjacent leads due to bridge over, solder not applied In addition, it solves the problem of continuity failure due to aging-induced fatigue fracture due to repeated heat cycles of the joints, etc., and resources and work associated with relatively frequent disposal and renewal use of degraded solder With the objective of improving efficiency, quality stability, and economic inefficiency, the junction reliability of micro-joints of microelectronic components has been dramatically improved And it provides a technical method and apparatus for enhancing.

The method and apparatus of the present invention is an apparatus for bonding and coating tin or a solder alloy on an electrode pad or lead surface of an electronic circuit board or electronic component, as shown in FIG. First, a solution 8 having a temperature of 120 to 350 ° C. containing 1 to 80% by weight of an organic fatty acid having 12 to 20 carbon atoms is sprayed onto the surface of the pad or the lead portion from the nozzle 14 and then immediately melted. The tin or solder alloy liquid 1 is supplied from the storage tank 2 by the dedicated pump 3 and sprayed in a jet form from the nozzle 4 to form a tin or solder film on the electrode pads or leads of the bonded electronic component 5. Furthermore, when it is desired to form a rust preventive film on the surface of the formed tin or solder film, a step of adding one nozzle and spraying the organic fatty acid solution 8 in a jet form from the additional nozzle is further provided. You can go. However, the organic fatty acid solution nozzle 14 and the molten tin or molten solder liquid nozzle 4 are arranged close to each other, the flow rate and flow rate of both liquids are adjusted, and the jet liquids are mixed and sprayed. An effect is obtained.
In the apparatus, the organic fatty acid solution or the molten tin or solder alloy liquid overflow 6 overflowed in each step is received by a guide rod 7 and transferred into a stirrer 9, and the inside of the stirrer By vigorously stirring and mixing the molten tin or solder alloy overflow and the organic fatty acid solution overflow, the copper oxide and flux components present on the surface of the electrode pad or lead portion of the tinned or solder-bonded electronic component 5 The contaminated overflow molten tin or solder alloy liquid is cleaned (in this case, copper oxide, tin oxide, or other additive metal oxide originally present in the molten tin or solder alloy liquid, In addition, oxidation impurities such as iron, lead, silicon, potassium and the like mixed in a trace amount are also removed and cleaned by the organic fatty acid solution), and then the mixed solution is stored in the organic fatty acid-containing solution storage tank 10. The purified molten tin or solder alloy liquid 11 introduced and separated by specific gravity difference in the organic fatty acid-containing solution storage tank is returned from the bottom of the organic fatty acid-containing solution storage tank to the tin or solder liquid storage tank 2 by the pump 12, By suppressing the time-dependent increase in the copper concentration and impurity concentration in the molten tin or molten solder liquid circulating and preventing impurities such as copper oxide and solder flux residue from being brought into the liquid storage tank 2, It is possible to continuously produce a large number of electronic components and printed circuit boards continuously for a long time by suppressing the change in composition of molten tin or molten solder alloy solution over time and stably providing high bonding reliability.
As a result, it is possible to prevent deterioration of bonding quality over time between lots produced during continuous tin or soldering, and a stable and highly reliable product with extremely small variation in bonding quality can be obtained.

More specifically, the organic fatty acid used in the present invention can be used even with a carbon number of 12 or less, but has water absorption properties, and is not so preferable because of its use at high temperatures. In addition, organic fatty acids having 21 or more carbon atoms have a high melting point and poor permeability and are difficult to handle, resulting in an insufficient rust preventive effect on the surface of the tin or solder alloy after treatment. Desirably, palmitic acid having 16 carbon atoms and stearic acid having 18 carbon atoms are optimal, and a solution having a liquid temperature of 120 to 350 ° C. comprising 1 to 80% by mass of any one of them and the remaining ester synthetic oil is used. By this, the solution can selectively take in impurities such as oxides and flux components present in the overflow molten tin or molten solder alloy liquid, and the overflow molten tin or molten solder alloy liquid can be cleaned. .
When the concentration of the organic fatty acid is 1% by mass or less, this effect is low and troublesome such as replenishment management, and when it is 80% by mass or more, smoke and odor problems occur in a high temperature range of 280 ° C. or more. This causes a problem in the stirring and mixing properties with the liquid. Therefore, the concentration range of 5 to 60% by mass is preferable.
The liquid temperature is determined by the melting point of the tin or solder alloy used, and it is necessary to vigorously stir and mix the organic fatty acid solution and the molten tin or solder alloy liquid at least in a high temperature region above the melting point.
Further, the upper limit temperature is about 350 ° C. from the viewpoint of smoke generation and energy saving, and is preferably a temperature from the melting point of the tin or solder alloy used to 300 ° C. or higher. The reason why the ester synthetic oil is mixed is to reduce the liquid viscosity to facilitate uniform stirring and mixing treatment and to suppress high-temperature smoke generation of organic fatty acids, and the concentration is determined by the organic fatty acid concentration.

For the stirrer and stirring method, put the above organic fatty acid and ester synthetic oil in a stainless steel container equipped with a heating device and stir using a batch type stainless steel impeller stirrer etc. while heating to a predetermined temperature. However, in this case, in order to sufficiently mix and react, it is necessary to take a long stirring time. Therefore, preferably, a static mixer is optimal, and when this is used, mixing and stirring can be efficiently performed in a short time, and copper oxide, flux components, or reaction products thereof in the overflow molten tin or molten solder alloy liquid Impurities can be removed efficiently.
The stirring time depends on the amount of molten tin or molten solder alloy overflow, the structure of the stirrer, and the stirring conditions, but if a static mixer is used, stirring and mixing for about 1 to 50 seconds is sufficient. Thereafter, when this stirred and mixed liquid is introduced into the organic fatty acid solution storage tank, the molten tin or molten solder alloy liquid that has been naturally cleaned at the bottom (lower layer) of the organic fatty acid storage tank due to the difference in specific gravity is transferred to the upper layer of the organic fatty acid solution. Copper oxide, tin oxide, or oxides of other added metals present in the overflow solution that has been incorporated in the form of saponified product by reacting with the carbonyl group of fatty acid, and trace amounts of iron and lead An organic fatty acid solution containing oxidative impurities such as silicon and potassium is separated. In this state, the cleaned molten tin or molten solder alloy liquid at the bottom (lower layer) of the storage tank is returned to the original molten tin or molten solder alloy liquid storage tank by a dedicated pump and supplied to the nozzle by another dedicated pump and jetted. The overflow liquid is circulated inside a stirrer such as a static mixer. Similarly, the organic fatty acid solution is also circulated and fed into a stirrer such as a static mixer by a dedicated pump.

In the present invention, the nozzle for jetting the high-temperature organic fatty acid solution 8 or the molten tin or molten solder alloy solution 1 may be independently provided with a nozzle having a tip shape as shown in FIG. For example, a composite nozzle having a tip shape such as b and c in FIG. 3 can also be used.
The material of the nozzle is desirably a material to which tin or solder does not adhere. For example, stainless steel, titanium, molybdenum, tungsten, or an alloy containing them as a main component is preferable.
Further, the same effect as that of the present invention can be obtained even when molten tin or molten solder is sprayed and suspended in a molten organic fatty acid solution in the form of fine particles and sprayed together from one nozzle. The width of the nozzle opening 15 is preferably 0.05 to 10 mm, depending on the ejection flow rate and the flow velocity. If it is 0.05 mm or less, too much load is applied to the pump. If it is 10 mm or more, tin or solder film is applied to a wide printed circuit board. This is not preferable because a large pump is required to secure the flow velocity of the jet when forming the liquid. On the other hand, the length of the nozzle opening is desirably the same as or slightly longer than the width of the object to be processed, and the jet from the nozzle opening is jetted at a uniform flow velocity and flow rate as much as possible in the longitudinal direction. For this reason, it is preferable to use a current plate (blade) inside the nozzle.
It is important to appropriately select the flow rate and flow rate of each liquid jetted from the nozzle according to the desired film thickness for forming a tin or solder film on the electrode pads or leads of the electronic circuit board or electronic component.

  As the kind of tin or solder alloy applicable to the present invention, any of those usually used for joining electronic components can be used. From the viewpoint of environmental problems and joining reliability, however, tin or tin is preferable. It is preferable to use a molten lead-free solder alloy to which one or more metals of silver, copper, zinc, bismuth, antimony, nickel, and germanium are added as components. Among them, a solder alloy of 1 to 3% by mass of silver, 0.1 to 1% by mass of copper, 0.01 to 0.5% by mass of nickel, and 001 to 0.02% by mass of germanium is particularly preferable.

A solution having a liquid temperature of 120 (the melting point of the lead solder alloy material used) to 300 ° C., which is composed of 1 to 80% by mass of the organic fatty acid having 12 to 20 carbon atoms and the remainder ester synthesis, is widely used at present. When the above-mentioned overflow of normal molten tin or molten solder alloy liquid is poured into a stirring mixer such as a static mixer and stirred and mixed, the copper oxidation present in the molten tin or molten solder alloy overflow liquid Oxide, tin oxide, silver oxide, or other added metal oxides and trace impurities such as iron, lead, silicon, and potassium react with the carbonyl group of organic fatty acids to be taken into saponified products. The overflow liquid is separated and removed from the inside of the overflow liquid to be cleaned. When this stirred mixed liquid is introduced into an organic fatty acid solution storage tank and allowed to stand, the molten tin or molten solder alloy liquid cleaned at the bottom (lower layer) of the storage tank due to a difference in specific gravity within 1 minute and outside, and its upper layer It naturally separates into an organic fatty acid solution containing the above impurities [Fig. 2].
Therefore, the molten tin or molten solder alloy liquid cleaned by the pump from the bottom is returned to the molten tin or molten solder alloy liquid storage tank of the soldering apparatus, and is supplied to the tin or soldering nozzle or slit by another pump. In the conventional equipment, the continuous quality of the joints between lots produced by continuous tin or soldering process is improved by injecting the overflow liquid into the agitator such as a static mixer and circulating it. Deterioration can be prevented, and long-term continuous processing of tin or solder alloy joints with extremely small variations in joint quality and stable and high joint reliability becomes possible.
Also, when soldering multi-layer printed circuit boards that contain a large number of through-holes in electronic components, the amount of solder to be joined to the multi-layer printed circuit board is large, so the molten solder liquid level in the liquid storage tank is at the minimum control level during continuous processing. However, in the case of the present invention, a necessary amount of solder having the same composition as that of the initial stage may be simply added, and continuous processing as in the conventional method is required. It is not necessary to prepare a low copper concentration solder to adjust the increased copper concentration due to the above, and it is not necessary to repeat frequent disposal and renewal of building baths due to a marked increase in copper concentration and deteriorated solder joint performance The apparatus and method of the present invention are very efficient from the environmental and economical viewpoints of resource saving and energy saving, and are industrially beneficial.

When the change in copper concentration and impurity concentration over time in the molten tin or molten solder alloy solution of the present invention treated under the above-mentioned conditions is examined, the effects of the present invention (Examples 1 and 2) are currently widely used. The continuous circulating tin or soldering device, ie, the molten tin or solder alloy liquid is sprayed onto the object to be soldered, and the overflow liquid is directly returned to the molten tin or molten solder liquid storage tank. Compared with the case of circulating use (Comparative Examples 1 and 2), the copper concentration, flux components and reaction products of Comparative Examples 1 and 2 and the concentration of impurities such as metal oxides increase with time, In Examples 1 and 2 of the present invention, it was found that the copper concentration clearly changes little even when continuously used for a long time, and the other impurity concentrations are reduced.
Furthermore, almost no deterioration in solder wettability with time was observed, the solder wettability during soldering was much better, and the viscosity at the time of melting was low, which was confirmed to be optimal for soldering of minute parts.
That is, even in an extremely narrow pitch printed circuit with a lead area of 0.08 mmφ and an adjacent lead interval of 0.08 mm, there is no over-volume (horn, wiggle), bridge over and leakage to the adjacent lead, and further the soldering There is no partial unattachment, and there is no electrical circuit continuity failure due to fatigue breakage of the small solder joints accompanying high and low temperature heat cycles, and the tin or solder joints of the present invention and method are extremely excellent in long-term connection reliability. I found out.

Examples and comparative examples

Comparative Example 1

  In the conventional circulating jet automatic continuous soldering apparatus shown in FIG. 1, a lead-free solder alloy composed of 2.5% by mass of silver, 0.5% by mass of copper, and the remaining tin is put in a storage tank 2 and melted. The molten lead-free solder alloy liquid 1 is transferred to the nozzle 4 and is formed into a multilayer (4 Layer) The molten lead-free solder alloy liquid 1 is jetted and sprayed from the nozzle to the copper land portion and through-hole portion of the printed circuit board surface 5, and all of the overflow liquid (overflow liquid) 6 is received by the flange 7, It was returned directly to the storage tank 2 and circulated for continuous use.

Comparative Example 2

  The same conventional circulating jet automatic soldering as in Comparative Example 1 was conducted with a lead-free solder alloy consisting of 2.5% by mass of silver, 0.5% by mass of copper, 0.01% by mass of nickel, 0.005% by mass of germanium, and the balance tin. The molten lead is put in a storage tank 2 of the apparatus [FIG. 1], and the molten lead-free solder alloy liquid 1 is transferred to the nozzle 4 by a pump 3, and the copper land portion of the multilayer printed circuit board surface 5 of the same type and the same lot as in the comparative example 1 The molten lead-free solder alloy liquid 1 was jetted and sprayed from the nozzle to the through-hole portion, and all of the overflow liquid 6 was received in the tank 7 and circulated directly back to the storage tank 2 for continuous use.

  In the improved circulating jet automatic continuous soldering apparatus of the present invention shown in FIG. 2, first, a solution 8 having a liquid temperature of 280 ° C. comprising 5% by mass of palmitic acid and the remaining ester synthetic oil is fed from the nozzle 14 to the above Comparative Example 1. The same kind of the same lot of multilayer printed circuit board surface 5 is sprayed onto the electrode pads and through-holes, and then the same composition as in Comparative Example 1 2.5% by mass of silver, 0.5% by mass of copper, and the remaining tin A molten lead-free solder alloy solution in which a lead-free solder alloy composed of the above is put into a storage tank 2 is transferred to a nozzle 4 by a pump 3, and the electrode pad and through-hole portion on the surface 5 of the multilayer printed circuit board are transferred from the nozzle 4 Molten lead-free solder alloy liquid 1 was sprayed. All of the overflow liquid 6 is received by a jar 7 and sent from the upper part of the static mixer 9 to the inside, and both liquids are vigorously stirred and mixed in the static mixer, and this mixed liquid is added to the palmitic acid solution storage tank from the lower part of the static mixer. 10 and the molten lead-free solder solution 11 deposited on the bottom of the palmitic acid solution storage tank due to the difference in specific gravity is circulated back to the original molten lead-free solder solution storage tank 2 with its dedicated pump 12 and continuously used. The palmitic acid solution 8 in the upper part of the acid solution storage tank was supplied to the upper part of the static mixer 9 by another pump 13 and circulated for continuous use.

  Similarly, in the improved circulating jet automatic continuous soldering apparatus of the present invention shown in FIG. 2, first, a solution 8 having a liquid temperature of 260 ° C. composed of 40% by mass of palmitic acid and the remaining ester synthetic oil is fed from the nozzle 14 to the above comparative example. 1 and the same kind of the same lot of the multilayer printed circuit board surface 5 of the surface of the electrode pad and through-holes are jet sprayed, and then the same composition as in Comparative Example 2, 2.5% by mass of silver, 0.5% by mass of copper, A molten lead-free solder alloy liquid containing 0.01 mass% nickel, 0.005 mass% germanium, and the remainder tin in the storage tank 2 is transferred to the nozzle 4 by the pump 3, and the multilayer printed circuit The molten lead-free solder alloy liquid 1 was jetted from the nozzle 4 onto the electrode pads and through-hole portions on the plate surface 5. All of the overflow liquid 6 is received by a jar 7 and sent from the upper part of the static mixer 9 to the inside, and both liquids are vigorously stirred and mixed in the static mixer, and this mixed liquid is added to the palmitic acid solution storage tank from the lower part of the static mixer. 10 and the molten lead-free solder solution 11 deposited on the bottom of the palmitic acid solution storage tank due to the difference in specific gravity is circulated back to the original molten lead-free solder solution storage tank 2 with its dedicated pump 12 and continuously used. The palmitic acid solution 8 in the upper part of the acid solution storage tank was supplied to the upper part of the static mixer 9 by another pump 13 and circulated for continuous use.

Regarding the time-dependent changes in the copper concentration and impurity concentration in the lead-free solders of the comparative examples and examples, the number of soldering processed sheets before the continuous use (initial state, blank) and the printed circuit board is 50,000. Sampling was performed from each solder solution storage tank after 100,000 sheets, and quantitative analysis was performed using an ICP emission analyzer (model 7500, manufactured by Shimadzu Corporation). As for solder wettability, similarly, the soldering wetness of each printed circuit board is sampled from each solder solution storage tank before the continuous use and after the printed circuit board is passed through 50,000 sheets and 100,000 sheets, respectively. The zero crossing time was measured at a repetition of 4 (n = 4), respectively, by the property test method. At that time, 0.4 mmφ pure copper wire was used as the measurement pin.
Further, the physical-mechanical evaluation method is that stainless steel (SUS 304) is sampled from each solder solution storage tank before the continuous use and after the number of soldered processed printed circuit boards is 50,000 and 100,000 after passing. ) Using a casting mold (JIS No. 6), create a test piece with a distance between ratings L = 50 mm, diameter 8 mmφ, chucking length L = 20 mm, diameter 10 mmφ, and Shimadzu Corporation according to the test method of JIS Z 4421) Using a tensile tester (AG100 type), the test measurement was repeated at a room temperature of 25 ° C. with a repetition rate of 2 (n = 2) at a load rate of 5 mm / min.

The result is as shown in [Table 1] below, but there is no significant difference between Example 1 and Comparative Example 1 and between Example 2 and Comparative Example 2 in each characteristic value before continuous use. In the case of Comparative Circuit 1 and Comparative Example 2, the copper concentration is remarkably increased, the solder wettability is deteriorated, and the physical mechanical property value is also decreased after the continuous passage processing amount of the printed circuit board is 50,000 and 100,000. It was found that the elongation became smaller and harder and weakened with time, and over-volume (horn, icicle), bridge-over (leak), and non-arrival were observed.
On the other hand, in Example 1 and Example 2 of the present invention, there is almost no increase in the copper concentration even after the continuous circuit processing amount of the printed circuit board is 50,000 and 100,000, and the solder wettability is reversed. Although it improved, the physical mechanical property value increased slightly, but there was no overvolume (horn, icicle), bridge over (leakage), or no arrival, and the iron impurity concentration decreased on the contrary. It was found that the elongation of the mechanical properties was slightly increased.

Industrial applicability

  As described above, the technology of the present invention clearly has a high elongation and toughness not found in conventional lead-free solder alloys, especially the risk of joint breakage due to repeated heat cycle fatigue of small area joints, and therefore miniaturization of electronic equipment solder joints This is an industrially valuable technology as a lead-free solder alloy that enables long-term high reliability.

It is a typical schematic diagram of the conventional circulating jet type automatic continuous soldering device for electronic parts. It is a typical schematic diagram of the example of the circulating jet automatic continuous soldering device for electronic parts of the present invention. It is a typical schematic diagram of the tip part shape example of the nozzle used for the circulation jet type automatic continuous soldering device for electronic parts of the present invention.

DESCRIPTION OF SYMBOLS 1 Molten tin or solder alloy liquid 2 Storage tank of molten tin or solder alloy liquid 3 Pump for transferring molten tin or solder alloy liquid 4 Nozzle for jetting molten tin or solder alloy liquid 5 Printed circuit board or electronic component 6 After jet spraying Overflow (overflow) overflow liquid 7 Metal bowl for receiving overflow liquid 6 8 Organic fatty acid solution 9 Stirrer 10 Organic fatty acid solution storage tank 11 Cleaned molten tin or solder alloy liquid 12 Cleaned melt Tin or solder alloy solution transfer pump 13 Organic fatty acid solution 8 transfer pump 14 Nozzle 15 for jetting organic fatty acid solution Nozzle tip opening

Claims (8)

  In an apparatus for forming tin or a solder film on the surface of an electrode pad or lead part of an electronic component, a tin or solder film is formed. An organic fatty acid having 12 to 20 carbon atoms is added to the surface of an electrode pad or lead of an electronic component from a nozzle. The organic material overflows after forming a tin or solder alloy film by spraying a solution of 80% by mass and the remaining ester synthetic oil at a temperature of 120 to 350 ° C. and a molten tin solution or a molten solder alloy solution in a jet shape. The fatty acid solution and the molten tin or molten solder alloy liquid are transferred to a stirrer, and vigorously stirred and mixed in the stirrer to thereby mix copper oxide and flux components mixed in the overflow liquid and their reaction products, Furthermore, copper oxide, tin oxide, or other additive metal oxide originally present in the molten tin or molten solder alloy liquid, and a trace amount Contaminants such as oxidation impurities such as iron, lead, silicon and potassium are also taken into the organic fatty acid solution to clean the overflow molten tin or molten solder alloy liquid, and then the mixed liquid is mixed with the organic fatty acid. The purified molten tin solution or molten solder alloy solution introduced into the fatty acid solution storage tank and separated by the specific gravity difference in the organic fatty acid solution storage tank is pumped from the bottom of the organic fatty acid solution storage tank to the molten tin or molten solder solution storage tank. A tin or soldering device for electronic parts, characterized by being returned and circulated.   The organic fatty acid according to claim 1, wherein any one of palmitic acid and stearic acid is used.   The molten tin or solder alloy liquid according to claim 1 is a molten lead-free solder alloy containing tin as a main component and at least one metal selected from silver, copper, zinc, bismuth, antimony, nickel, and germanium added thereto. A tin or soldering apparatus for electronic parts, characterized in that   The stirrer according to claim 1 is a tin or soldering apparatus for electronic parts, wherein a static mixer is used.   In the method of forming tin or a solder film on the surface of an electrode pad or lead part of an electronic component, a tin or solder film is formed. An organic fatty acid having 12 to 20 carbon atoms is added to a surface of an electrode pad or lead of an electronic component from a nozzle. The organic material overflows after forming a tin or solder alloy film by spraying a solution of 80% by mass and the remaining ester synthetic oil at a temperature of 120 to 350 ° C. and a molten tin solution or a molten solder alloy solution in a jet shape. The fatty acid solution and the molten tin or molten solder alloy liquid are transferred to a stirrer, and vigorously stirred and mixed in the stirrer to thereby mix copper oxide and flux components mixed in the overflow liquid and their reaction products, Furthermore, copper oxide, tin oxide, or other additive metal oxide originally present in the molten tin or molten solder alloy liquid, and a trace amount Contaminants such as oxidation impurities such as iron, lead, silicon and potassium are also taken into the organic fatty acid solution to clean the overflow molten tin or molten solder alloy liquid, and then the mixed liquid is mixed with the organic fatty acid. The purified molten tin solution or molten solder alloy solution introduced into the fatty acid solution storage tank and separated by the specific gravity difference in the organic fatty acid solution storage tank is pumped from the bottom of the organic fatty acid solution storage tank to the molten tin or molten solder solution storage tank. A tin or soldering method for electronic parts, characterized by being returned and circulated for use.   The organic fatty acid according to claim 5, wherein any one of palmitic acid and stearic acid is used.   The molten tin or solder alloy liquid according to claim 5 is a molten lead-free solder alloy containing tin as a main component and at least one metal selected from silver, copper, zinc, bismuth, antimony, nickel, and germanium added thereto. Used tin or soldering method for electronic parts.   6. The tin for electronic parts or the soldering method according to claim 5, wherein the stirrer is a static mixer.

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