JP2003033894A - Soldering material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soldering material which does not contain lead, exerts excellent wettability for a joining member and has versatility and easiness for handling, and the manufacturing method thereof. SOLUTION: The first metal material is coated by the thin layer second metal material to obtain a coated body, and the coated body is drawn and molded into a linear shape by rolling to obtain a linear soldering material. Moreover, a granular soldering material is obtained by cutting the linear molded body in the direction crossing the axis of the drawn-molded linear molded body and granulating it. The soldering materials 4 have the first metal layer 6 and the second metal layer 5 which have different compositions, the first metal layer is formed into a shape having an axial property drawn in the uniaxial direction, and the first metal layer is coated with the second metal layer so as to surround the axis of the first metal layer. The first metal layer contains zinc, and the second metal layer does not contain zinc but contains tin.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic parts and mechanical parts.
Used for joining various metal parts such as
A method for producing the same. In detail, it does not contain lead,
Solder material that can form a good joint in joining products
It relates to the manufacturing method. [0002] Soldering is performed by using a material having a low melting point.
This is a technology for joining objects together.
Can be traced back to the ancient Mesopotamian civilization
Has been done. In modern industry, soldering is mechanical
Widely used for simple assembly and joining of electronic equipment, for example,
In electronics, semiconductors, microprocessors,
For mounting electronic components such as memory and resistors on a substrate
It is used for bonding mounting boards and the like. Its strength is its parts
In addition to fixing the
The formation of an electrical connection by conductivity,
It differs from organic adhesives in this respect. [0003] Commonly used solders are tin and lead.
Eutectic solder with a eutectic point of 183 ° C
It is used for joining plate materials such as nickel and copper. With solder
Not only below the melting point of the
The characteristic that the thermosetting resin is lower than the temperature at which gasification starts
Have signs. This eutectic solder has a tin component of copper.
A unique intermetallic compound layer is formed at the board interface,
It is also known to increase the adhesive strength of the rubber. This
In addition to tin and lead eutectic solder with such characteristics,
Attempts to use solder with zinc, solder with silver and tin, etc.
But difficult to join due to poor wettability.
It has not been. As described above, the manufacture of electronic equipment and various devices
Soldering is still important in
Today's personal computers, mobile phones and
The rapid spread of personal devices such as jars
As we proceed, the importance of solder is increasing. [0005] The spread of electronic devices has been
They enrich their lives. But on the other hand, use
It is also true that a lot of lost electronic equipment is discarded
And there is a risk that waste will cause environmental pollution.
ing. For this reason, waste is recycled and hazardous
Production methods that do not use expensive substances have been proposed. In particular,
The elimination of highly harmful substances is said to prevent environmental pollution.
From the viewpoint of
Needs development. At present, lead is not contained due to the problem of environmental pollution.
There is a need for a joining technique using solder. Place
However, in the case of a solder that replaces lead with another metal or a combination of other metals
Soldering avoids adverse effects on the base material due to high temperatures
It is difficult to lower the soldering temperature as
Poor adhesion to base metal with very poor bonding properties
Such as semiconductor mounting
It is difficult to use for general soldering, let alone solder processing
New In particular, for tin and zinc solder,
Practical use in electronics packaging due to too many issues
Is considered difficult (Tadashi Takemoto: “Joint Science”
Pb Free Solder from the Viewpoint, 5th Environmentally Friendly Mounting Technology
Forum lectures (see May 14, 1997)). [0007] Thick film formation, conductor circuit formation and semiconductor mounting
Use of lead-free solder for such fine soldering process
Mix the solder powder and flux to make
Screen using combined paste solder paste
Printing methods and the like have been proposed. However, solder paper
The flux used for the strike is JIS Z3284
As described, organic compounds, inorganic compounds and resins are roughly classified.
However, when an organic compound or resin is used,
Active ingredients include amino acids, halogen salts of amino groups and organic acid salts.
As an inorganic compound.
Ammonium, zinc halide, tin halide, phosphoric acid,
Often, hydrogenic acid or the like is added. like this
Since additives have the effect of corroding metals, solder
Corrosion due to flux residue after paste reflow
Inspection is required. Also, to remove flux
Processing of organic substances vaporized when the paste is heated is required
There is also a problem that is. Accordingly, the present invention provides a lead-free solder.
It is a material that shows good wettability to the members to be joined,
Solder material with versatility and easy handling
It is intended to provide a manufacturing method. Means for Solving the Problems Accordingly, the present inventors have
Lead is used to eliminate environmental pollution from lead in waste.
Soldering using a highly versatile metal solder
As a result of intensive research on
Tin / zinc solder joint with sufficient joint strength due to solder material
It has been found that a combination can be easily formed. Of this solder material
The structure can be used to form solder joints of other metals.
Available. Further, the solder material having the above-mentioned multilayer structure is used.
Finding that it can be manufactured by a simple method
Was. The solder materials according to the present invention have different compositions from each other.
Solder material having a first metal layer and a second metal layer
The first metal layer has an axial property extending in a uniaxial direction.
The second metal layer wraps around the axis of the first metal layer.
The first metal layer is coated to surround. The first metal layer contains zinc, and the first metal layer contains zinc.
The second metal layer contains tin substantially without zinc. The overall shape of the solder material is substantially spherical.
Can be. Further, the method for producing a solder material according to the present invention comprises the following steps:
Covering the metallic material with a thin metallic second metallic material to form a cover.
Obtaining step and stretching the coated body into a linear shape by rolling.
And [0015] The above production method may further comprise the step of forming a stretched linear shape.
The linear compact is cut in a direction intersecting with the axis of the compact,
Wherein the first metal material contains zinc.
The second metal layer does not substantially contain zinc but contains tin.
Have. DETAILED DESCRIPTION OF THE INVENTION Tin / zinc solder is a conventional solder.
Inferior wettability compared to, low cost, low melting temperature,
Also, in joining electronic components, solder is more expensive than tin / lead solder.
Because the generation of irrigation is suppressed,
Is a very effective material. Tin / zinc alloy wettability
Inferior is that zinc is very easily oxidized,
A zinc oxide film is formed on the surface to prevent the alloy from wetting the base material.
The inventors of the present application have found that it is caused by harm.
In other words, tin / zinc solder can be used in place of conventional solder
To do so, it is necessary to deal with the oxidation of zinc. The present invention provides a method for forming tin / zinc solder.
By other substances to shield the zinc component of the atmosphere
Proposal of a multi-layered solder material that surrounds the zinc component with a coating layer
The zinc component is located inside the coating layer
Reduce or substantially reduce the area where the zinc component is exposed to the atmosphere
The solder material is melted by heating.
The formation of zinc oxide is suppressed until the
It becomes a uniform molten solder and at the same time wets the surface of the component
A good bond is formed. The coating layer of the solder material is easily removed by heating.
Organic materials and metals other than zinc.
Wear. The coating layer is formed by organic matter that can be easily removed by heating.
If it is formed, place the solder material between the members to be joined
While heating to form the bond, the coating layer bonds by heat.
Is removed from the member that is
A dam junction is formed. Thus, the covering layer forms a bond
Does not affect the composition of the solder. On the other hand, metals other than zinc
When forming a coating layer, the metal component of the entire solder material
A solder joint is formed by melt-mixing of. Therefore,
The composition of the solder that forms the bond depends on the total solder material including the coating layer.
Determined by the metal composition of the body. In any case
Three or more layers with a metal other than zinc placed outside the coating layer
Although it is possible to take the above multilayer structure,
Describes the solder material with the coating layer as the outermost layer.
I will tell. In addition, the hand of the structure which has an additional layer outside the coating layer
About da materials, apply and change as appropriate based on the following description
Can be obtained. Tin / Zinc solder
For other solder materials, multiple layers presented in this application
It can be provided as a structural solder material. The coating layer is made of an organic material which can be easily removed by heating.
In this case, as shown in FIG.
The inner layer 3 inside the covering layer 2 of the material 1 forms a bond
Tin and zinc in a proportion corresponding to the tin / zinc solder composition
Contains tin mixed layer and zinc mixed layer, tin
/ Uniform form by zinc alloy layer, and composite form of these
Any form may be used. In addition, tin and zinc
If other metal outside is added to the inner layer portion 3, tin and zinc are contained.
Ternary alloy solder or more multi-element alloy solder
Can be. Heat the mixed layered solder material.
Then, at the tin / zinc eutectic point temperature, the contact area between tin and zinc
Begins to melt from the minute, a tin / zinc eutectic is formed and the temperature rises
In accordance with the above, the metal composition of the entire inner layer portion 3 progresses.
Completely melted at the liquidus temperature at. Therefore,
In order for the solder material to melt at a low temperature, the inner layer of the solder material
3 Preferably, the overall metal composition is close to the tin / zinc eutectic composition.
In order to melt quickly and quickly, the inner layer
Preferably, it is a uniform state by the gold layer. Make the coating layer 2
Organic substances that can be easily removed by heating are solidified at room temperature.
Vaporized at a temperature lower than the melting temperature of the solder
It is a compound that is released as a gas when decomposed, etc.
Materials such as those used in dapaste flux are preferred.
New In particular, natural polymers such as rosin (pine resin component)
Resins are suitable, but are not limited thereto.
No. FIG. 1A shows a linear solder having a two-layer structure.
The material constitutes the inner layer part in the molten material such as resin that constitutes the coating layer
Immersed and removed the wire to cool and solidify the melt
It is obtained by rolling if necessary. Get
The granular solder material is cut by cutting the
can get. When the coating layer is formed of a metal other than zinc
Is a coating layer 5 of the solder material 4 as shown in FIG.
The inner layer part 6 inside is a single-layer form of a plain zinc layer,
Mixed layer of taste layer and simple zinc layer, depending on tin / zinc alloy layer
In any form, such as uniform form and composite form
There may be. However, the coating layer 5 and the inner layer part 6 were combined.
Tin / zinc solder in which the metal composition of the entire solder material forms a bond
Content of the coating layer 5 and the inner layer 6 so as to match the composition of the
Determine the amount. A metal other than tin and zinc is coated
Or if it is added to the inner layer 6, the solder that forms the bond
Ternary alloy solder containing tin and zinc or more
Multi-component alloy solder. The smell of heating this solder material 4
Even at the tin / zinc eutectic point temperature,
Melting begins to form a tin / zinc eutectic, which increases with increasing temperature.
Fusion uniformity progresses, and the metal composition of the entire solder material
Melts completely at the liquidus temperature. Therefore, the solder material is low.
In order to melt at a low temperature, the metal composition of the entire solder
It is preferable that the composition is close to the zinc eutectic composition, and the solder material is
For fast melting, the inner layer 6 is a tin / zinc alloy layer.
Is preferred. As an example satisfying this, for example, tin / sub
Inner layer made of alloy with a composition of tin slightly less than that of lead eutectic
6 and the composition of the entire solder material is the same as the tin / zinc eutectic composition.
The coating layer 5 is formed with a small amount of tin so that
No. However, in practice, the dimensions of the solder material (thick
Is about several millimeters, it takes a long time for heat conduction.
Since the inner layer 6 is not made of a tin / zinc alloy,
Is quickly homogenized by melt diffusion. Effective enough for practical use
As an example of a solder material with a simple configuration, a coating layer of plain tin
A two-layer solder material covering the plain zinc inner layer
You. This solder material has a simple structure and is complicated to manufacture.
Can be easily manufactured without the need for complicated processing.
Always advantageous. Hereafter, plain zinc is used in the coating layer of plain tin.
The two-layered solder material covering the inner layer will be described. The plain zinc layer was covered with a plain tin coating layer.
As an example of a solder material having a two-layer structure, FIG.
Solder members 7a and 7 having a circular cross section as shown in FIG.
b, a wire or a sphere having such a cross-sectional shape
Can be produced as shaped particles. (A)
The zinc inner layer 9a is covered with the tin coating layer 8a, and in FIG.
A number of zinc inner layers 9b are covered with a tin coating layer 9b.
Also, as shown in (c) and (d), the cross section is an elliptical linear shape or
Are used for the elliptical solder materials 7c and 7d and (e) and (f).
The cross-sectional shape as shown is a polygonal line, polygonal column, or
It can also be manufactured as a face-piece solder material 7e, 7f
You. Also in the case of such a cross-sectional shape, FIGS.
Thus, the plurality of zinc inner layers 9d and 9f are
8f. It has a two-layer structure having a sectional shape as shown in FIG.
Production of solder material to be used is the production of linear solder material with a two-layer structure.
Basically, the granular solder material is a two-layered linear solder
Can be manufactured. First, the linear solder material
Manufacturing will be described below. The linear solder material having a two-layer structure is made of a zinc rod or a bar.
Wraps a thin layer of tin around the mass and rolls it
Etc. and gradually stretched into a thin line of uniform thickness
Thus, it can be easily manufactured. use
The amount of thin-layer tin and zinc bars or lumps is determined by the amount of solder
To the composition ratio of the mixture. Preferably, tin 85-97
Parts by weight and 3 to 15 parts by weight of zinc. Rolling
In order to make tin and zinc easy to stretch-mold, tin and zinc are
Temperature at which it does not melt, ie, lower than the tin / zinc eutectic temperature
The heating is preferably performed at about 50 to 198 ° C.
By this method, the diameter is about 2 μm to 20 mm,
Linear solder material with an average lead inner layer diameter of about 1 μm to 10 mm
Can be manufactured. Also, a thick rod or thin sheet
It can be rolled into
This also relates to the present invention. As shown in FIGS. 2 (e) and 2 (f)
Solder material with a polygonal cross section is used in the rolling process.
Adjust the pressure applied in the
By pressing the stretched linear solder material using a mold
Is obtained. The linear solder material obtained in this way
Is that only a small portion of the edge is exposed to zinc
It ’s only a surface and it ’s virtually isolated from the atmosphere.
The same as the wire solder made of tin only
Can be used for soldering in the same manner
Soldering can be performed properly using a soldering iron, etc.
You. Substantially suppressed zinc oxidation during the soldering operation
Accordingly, the solder material shows good wetting to the member. Atmosphere
Good solder joints can be formed even in ambient air
You. The linear solder material having the two-layer structure can be manufactured by another manufacturing method.
Can also be manufactured. In this manufacturing method,
Using a zinc wire or rod and molten tin, adjust the temperature of the molten tin.
Maintain a temperature slightly higher than the melting point of tin and add zinc
Soak the wire for a short time and take it out immediately.
The molten tin adhering to the material is cooled and solidified. Zinc wire or rod
Is preferably cooled before dipping in molten tin. this
Then, the zinc coated wire or bar coated with tin is appropriately rolled and
By drawing until the diameter becomes
It is. Alternatively, a thin tin wire or tin foil around the zinc wire
Is wound tightly in a coil, and this is pressed using a rolling mill.
It can also be stretched to a desired diameter.
Can be obtained. At this time, rosin with tin wire
When wires are lined up and wrapped around a zinc wire, tin and pine
A linear solder material having a coating layer made of fat is obtained. In the linear solder material 4 as shown in FIG.
The outer diameter of the coating layer 5, that is, the outer diameter d1 of the solder
The diameter d2 of the layer 6 is in the range represented by the following equation (1).
Is appropriate. (1/100) d1 ≦ d2 <d1 (1) In particular, the diameter d2 of the inner layer 6 containing zinc is 1 μm on average.
When the distance is about 3 mm, the range represented by the following formula (2) is preferable.
Good. As shown in (b), (d) or (f) of FIG.
In order to provide a plurality of inner layer portions in the die material, d2 is about 1 / d1 of d1.
It is preferably smaller than 4. (1/90) d1 ≦ d2 <(999/1000) d1 (2) The granular solder material is a linear solder material having a two-layer structure obtained as described above.
It is manufactured using First, cross the linear solder material with the axis
3A, the zinc inner layer 9 is cut as shown in FIG.
A cylindrical solder around which a tin coating layer 8 surrounds the axis as the axis center
A piece 10 is created. In FIG. 3A, the linear hand
The cutting is performed perpendicular to the axis along the radial direction of the material,
It may be performed diagonally. The cylindrical solder piece 10 is vibrated.
When supplied on a heating plate, the solder pieces 1
The tin coating layer 8 is formed by the collision between the corner of 0 and the plate and heat.
Is deformed, and the tin coating layer 8 gradually covers both end faces of the zinc inner layer portion 9.
It becomes round while covering, and gradually the solder piece 11 of (b)
It becomes almost spherical. Therefore, the heating temperature of the heating plate
By adjusting the temperature and the residence time of the solder pieces as appropriate.
Almost spherical in which the inner lead layer 9 is completely covered by the tin coating layer 8
It is possible to obtain a granular solder material having a shape. Vibrating heating pump
Instead of supplying a cylindrical solder piece 10 on the rate,
Roll the cylindrical solder piece 10 on the inclined heating plate
Is also good. In this case, heat the plate so that the tin is easy to soften.
Temperature is set high and the temperature inside the solder piece rises
Reduce the time to roll on the heating plate
As a result, only the tin coating layer 8 is thermally deformed and the zinc inner layer 9
It is possible to obtain a solder material that is almost completely covered with
You. By such a method, the average particle size is about 2 μm to 2 μm.
A granular solder material of about 0 mm can be obtained. The solder pieces shown in FIG. 3A are cut at both ends.
In the cross section, the zinc inner layer 9 is exposed to the atmosphere.
In this part, oxides are generated, but the volume of zinc
The exposed area is extremely small compared to
Close to the atmosphere,
It doesn't matter much. Therefore, the granular solder material of the present invention
It can be used as Also, use a linear solder material as a solder piece.
When cutting, use a pair of cutting blades to remove the linear solder material.
Cutting by sandwiching may cause plastic deformation of the metal.
Therefore, the zinc inner layer 9 as shown in FIG.
A solder piece 12 that is not exposed is obtained. Push cut for each cutting surface
The cutting direction of the blade is 90 degrees each in the axial direction of the linear solder.
When rotated, a solder piece 13 as shown in FIG.
Can be Such solder pieces 12, 13 are solder pieces 11
Exerts substantially the same effect as that of the granular solder material of the present invention.
Can be used effectively. Squeeze many push cutting blades
You may use the pushing-off device comprised in the shape of a rifle. By pushing
The shape of the cut surface formed by pressing and cutting
Can be adjusted by speed. (D) Solder pieces
In 13, press cutting to increase the inclination of the cut surface
Use a blade to reduce the length of the solder piece in the axial direction.
When it is manufactured, a granular solder material with a shape close to tetrahedron is obtained.
You. With the use of a heated cutting blade, the plasticity of the linear solder
Deformation becomes easy, and the cut surface of the inner layer of zinc is covered with a thin film of tin.
Easy to cover, efficiency of cutting operation and inner layer of zinc with tin
Is improved. The lines having the cross-sectional shapes shown in FIGS.
Particulate solder in accordance with the above-described manufacturing method using a granular solder material
When the material is formed, the solder pieces shown in FIGS.
As in the case of 11 to 13, the zinc inner layer 9 is
A granular solder material having a similar structure covered with the solder is obtained. Furthermore,
The above-described method for producing the linear solder material and the granular solder material uses tin.
Solder material or alloy with a coating layer of a metal other than
It can be applied to the production of solder material having an inner layer and a coating layer,
Constructs a thin metal material and an inner layer for forming the coating layer
Perform the same operation using a metal bar or lump for
And a two-layered linear solder material having a desired composition and
A granular solder material can be obtained. Furthermore, concentric cylindrical
Linear and granular solder materials having a structure having multiple layers
Is also possible. In rolling and graining processes
Depending on the degree of heating, the inner layer and the coating layer
May be merged and continued. In such a case
The zinc in the inner layer must diffuse to the outer surface of the coating layer
Oxidation by zinc atmosphere during soldering operation is suppressed.
The solder material is in line with the spirit of the present invention.
I can say. Another example of the solder material according to the present invention is shown in FIGS.
As shown in FIG. (A) to (c) of FIG.
, Hexagonal and star-shaped zinc inner layer 9 covered with tin coating layer 8
Cylindrical solder materials 14, 15, 16 are shown. this
Also manufacture by applying the manufacturing method described above.
Can be For example, the cross section is square, regular hexagon
Or immerse a star-shaped zinc wire in molten tin and cool and solidify the tin
Repeat the process a predetermined number of times to form a tin coating layer of desired thickness
And then rolling it into a fine wire
Obtained. Alternatively, use ultra-fine zinc wire and tin wire.
In order to obtain a cross section similar to the shape of FIG.
And tin wires are stacked and crimped, and then rolled.
May be processed into a thin line shape. Or these methods
And the above-described methods may be appropriately combined for production.
These particles are formed using the cutting method described with reference to FIG.
If it turns into a square, regular hexagon or star-shaped cross section inside
Thus, a granular solder material having a zinc layer is obtained. like this
The solder material is composed of the tin coating layer 8 and the zinc
Since the ratio of the area of the boundary surface with the lead inner layer 9 increases,
It is said that the internal homogenization speed will be faster when the material is melted
It is excellent in point. FIG. 5 shows that it is manufactured in accordance with the present invention.
A specific example of a granular solder material that can be cut is shown. (A) to (c) grains
Solder materials 17, 18, and 19 are all linear solder materials.
When cutting into particles by cutting,
What can be obtained by applying pressure to perform pressure molding
it can. These are radiated at the end of the linear solder material.
Cutting after forming curved side parts using directional pressure
To obtain particles. Or
(A) The granular solder material 17 is cut into solder pieces.
At the same time as the compression in the axial direction.
In addition to these, cones, truncated cones, pyramids and truncated pyramids
A granular solder material can be manufactured in the same manner. The granular solder material 20 shown in FIG.
A linear hank having an elliptical cross section as shown in FIG.
When cutting da wood, squeeze the end by pressing and cutting operation
It is obtained by closing, and zinc is applied to the bag-shaped tin coating layer 8c.
The inner layer 9c is covered. Particulate solder shown in (e)
The material 21 is made of a cylindrical zinc inner layer 9g and a tin coating layer 8g
Obtained by cutting linear solder wound in a round shape
Then, the granular solder material 22 of (f) has a rectangular tin coating layer 8h and
Obtained by cutting a linear solder material having a zinc and zinc inner layer 9h
It is. The granular solder materials 17 to 22 shown in FIG.
Fix the position without rolling when placed on a flat surface
Can be installed between the members to be joined and soldered
It is convenient to do. Each of the granular solder materials according to the present invention has a
Since it is manufactured from a layered linear solder material,
Due to this manufacturing method, the structure of
There are features to come. In other words, the inner layer of the granular solder
As is evident from 3-5, the axialness stretched in the uniaxial direction
It has a shape that covers the axis of the inner layer.
A layer covers the inner layer. The grain shape of the solder material is perfectly spherical
The inner layer is elongated and axial even when molded into
And the inner layer has no stretchability like a perfect sphere
It is considered rare to be in a state. Production of the above-mentioned linear solder material and granular solder material
The production should be carried out at a concentration of oxygen of 100 ppm or less.
Oxygen concentration of less than 100ppm
Prevents oxidation of raw materials by using a neutral atmosphere as a working atmosphere
It is desirable to do. The linear solder material according to the present invention as described above and
Granular solder material is preferably used instead of conventional solder.
Limited to assembly and joining in the manufacture of machinery and equipment.
It can also be used to form micro junctions in the semiconductor field.
Can be. For example, conductive parts of IC packages and CPUs
Connection, connection of personal computers and printers, etc.
Used for cable connector and communication cable used
Connection in optical connectors, automotive radiators
Bonding, component mounting on a board, and the like. Mounting on board
Available in single-sided surface mount, double-sided surface mount, double-sided surface
Components with mounting leads, components with single-sided surface mounting leads
Mounting, lead-through mounting, etc. Also, as mounting parts
Ceramics, capacitors, and passive components
Ducters, jumpers, transistors, diodes, aluminum
Electrolytic capacitor, tantalum semi-fixed resistor, trimmer, carp
And the like, and active components include I
C and SI are typical examples. Package outline or shape
About SOIC, SOPQIP, QFP, PLC
C, LCC, SOJ, MSP, BGA, FC
-BGA, CSP, PLC, MCM, OE-MCM,
High-density mounting with multiple chips. Hereinafter, the present invention will be described in more detail with reference to Examples.
explain. Example 1 Nitrogen having an oxygen concentration of 100 ppm or less
Purity 9 in a glove box filled with elemental atmosphere
9 g of 9.99% pre-weighed wire-shaped zinc is added to 9 g of purity.
9.98% tin foil 91g is rolled and hardened
Was. At this time, the diameter of the roll around which the tin foil was wound was 5 mm. This
The roll is stretched stepwise using a rolling mill to reduce the diameter to 5 mm.
To 3.5mm, then from 3.5mm to 2mm and then to 2mm
To 1.2mm and finally from 1.2mm to 0.8mm
Thus, a wire having a diameter of 0.8 mm was obtained. Take up this wire
The oxygen content was measured using a part of the wire as a sample.
At this time, it is less than 50 ppm,
The content was 95% or more. Next, the soldering iron is heated to 220 ° C.
With the above-mentioned wire using the soldering iron of RMA type
QFP (208
pin, gold flash plating finish, 0.5mm pitch)
Reinforce the soldering of the part where the joint failure occurred
Was. As a result, the wire is melted by the soldering iron and
Melted solder shows good wetting and spreads to poor joints
Fills the gap between the pad and the lead, and appropriately reinforces it
Soldering was done. Example 2 Nitrogen having an oxygen concentration of 100 ppm or less
Purity 9 in a glove box filled with elemental atmosphere
Put 182 g of 9.98% pre-weighed tin into an elongated crucible
And melted by heating. Temperature finger on molten tin with thermocouple
The indicator is installed and the molten tin is gradually cooled, and the central part of the molten tin is cooled.
At a temperature of 235 ° C., a 99.99% pure zinc wire
18g of material is immersed in molten tin, taken out immediately and cooled sufficiently
did. This allows the zinc wire to be covered with solidified tin
The material was obtained. The diameter of this wire was 10 mm on average.
This wire is stretched step by step using a rolling mill to have a diameter of 10 mm.
To 7.5mm, then from 7.5mm to 5mm, and 5mm
From 3mm to 3mm and finally from 3mm to 2mm
Wire was obtained. Wind this wire and a part of the wire
When the oxygen content was measured as a sample, 50ppm
Below, the content of tin in the outer surface of the wire is 95%
That was all. Next, the soldering iron is heated to 220 ° C.
With the above-mentioned wire using the soldering iron of RMA type
QFP (208
pin, gold flash plating finish, 0.5mm pitch)
Reinforce the soldering of the part where the joint failure occurred
Was. As a result, the wire is melted by the soldering iron and
Melted solder shows good wetting and spreads to poor joints
Fills the gap between the pad and the lead, and appropriately reinforces it
Soldering was done. Example 3 Nitrogen having an oxygen concentration of 100 ppm or less
Purity 9 in a glove box filled with elemental atmosphere
Around 9g of 9.99% pre-measured wire zinc,
54.6g of tin wire with 99.98% purity and 3 rosin wires
A total of 8.1 g of the material was closely arranged and wound in a coil shape. this
The diameter of the roll around which the hour wire was wound was 5 mm. This b
Is drawn step by step using a rolling mill to reduce the diameter from 5 mm.
From 3.5mm, then from 3.5mm to 2mm, and from 2mm
To 1.2mm and finally from 1.2mm to 0.8mm
Thus, a wire having a diameter of 0.8 mm was obtained. Take up this wire
Using a portion of the wire as a sample, determine the oxygen concentration in the metal
The measured value was less than 100ppm.
The purity of the tin portion of the face portion was 95% or more. Next, the soldering iron was heated to 220 ° C.
With the above-mentioned wire using the soldering iron of RMA type
QFP (208
pin, gold flash plating finish, 0.5mm pitch)
Reinforce the soldering of the part where the joint failure occurred
Was. As a result, the wire is melted by the soldering iron and
Melted solder shows good wetting and spreads to poor joints
Fills the gap between the pad and the lead, and appropriately reinforces it
Soldering was done. At this time, pine resin is a claim solder
Gasification after acting equivalent to the flux used for
It is thought that it was done. (Embodiment 4) A cutting machine having a wedge-shaped blade is used.
And the wire obtained in Example 1 while checking with a magnifying glass.
Was cut and granulated into cylindrical pellets having a length of 1.5 mm.
This pellet is sucked with a suction straw and a BGA chip
(20pin) Solder bump position on the board for mounting
Placed side by side. Place the chip mounter in place on this
Equipped with a BGA chip using an oxygen concentration of 500 ppm
Maximum heating temperature of 230 ° C using the following nitrogen flow
The pellets melt and melt
The substrate and the BGA chip
Was joined. Example 5 Nitrogen having an oxygen concentration of 100 ppm or less
Purity 9 in a glove box filled with elemental atmosphere
9.98% pre-weighed tin 91g put in crucible and heated
Melted. 9g of 99.99% pure zinc in molten tin
And stir with a clean stainless steel spoon.
I made one. This molten metal is poured into a cylindrical mold and cooled.
And solidified. After this, the cylindrical alloy solidified from the mold
Was taken out. The diameter of this cylindrical alloy was 5 mm. This
Is gradually expanded using a rolling mill to reduce the diameter from 5 mm.
From 3.5mm, then from 3.5mm to 2mm, and from 2mm
To 1.2mm and finally from 1.2mm to 0.8mm
Thus, a wire having a diameter of 0.8 mm was obtained. Rosin-based low
Dissolves melting point flux (WW system, manufactured by Senju Metal Industry Co., Ltd.)
Then, immerse the obtained wire in the flux and take it out.
Cooled and wound. A part of the wound wire is used as a sample.
When the oxygen concentration in the metal part was measured,
Below, the metal composition was almost uniform. Next, the soldering iron is heated to 220 ° C.
With the above-mentioned wire using the soldering iron of RMA type
QFP (208
pin, gold flash plating finish, 0.5mm pitch)
Reinforce the soldering of the part where the joint failure occurred
Was. As a result, the wire is melted by the soldering iron and
Melted solder shows good wetting and spreads to poor joints
Fills the gap between the pad and the lead, and appropriately reinforces it
Soldering was done. As described above, the solder material of the present invention
Is free of lead and can be used in air
It is a solder material with a multi-layer structure as shown, joining various components
Therefore, its industrial value is extremely large.
Further, the method for producing a solder material according to the present invention includes
Structured solder material can be easily manufactured, and high quality solder material can be produced.
Can be supplied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows two embodiments (a) of a solder material according to the present invention.
Sectional drawing which shows (b). FIG. 2 is a sectional view showing six specific examples (a) to (f) in the embodiment (b) of FIG. 3 shows specific examples (a) to (d) of a granular solder material produced from a linear solder material corresponding to the specific example (a) of FIG.
(Left: view in the axial direction, right: view in the radial direction). FIG. 4 is a perspective view showing another specific example (a) to (c) in the embodiment (b) of FIG. 1; FIG. 5 is a perspective view showing other specific examples (a) to (f) of the particulate solder material according to the present invention. DESCRIPTION OF SYMBOLS 1,4 Solder material 2,5 Coating layer 3,6 Inner layer portions 7a-7f Solder material 8,8a-8h Tin coating layer 9,9a-9h Zinc inner layer portions 10,11,12,13 Solder pieces 14, 15, 16 Solder material 17, 18, 19, 20, 21, 23 Granular solder material

Continuation of front page    (72) Inventor Izumi Komatsu             8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa             Toshiba Yokohama Office (72) Inventor Mitsuhiro Tomita             8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa             Toshiba Yokohama Office

Claims (1)

Claims 1. A solder material having a zinc layer and a tin layer, wherein the zinc layer has a uniaxially stretched axial shape, and the tin layer has an axis of the zinc layer. Wherein the zinc layer is coated so as to surround the tin layer, and the ratio of the tin layer to the zinc layer has a tin / zinc eutectic composition.