KR101062706B1 - Attachment method of solder powder and manufacturing method of soldering electronic circuit board - Google Patents

Abstract

The method of attaching the solder powder comprises the steps of treating the exposed metal surface of the electronic circuit board with a tackifying compound to impart tack to the metal surface to form an adhesive portion, and supplying a solder powder slurry suspended in liquid to the adhesive portion. Inducing adhesion of the solder powder. A method of manufacturing a soldering electronic circuit board includes treating an exposed metal surface of an electronic circuit board with a tackifying compound to impart tack to the metal surface to form an adhesive portion; Supplying a solder powder slurry suspended in a liquid to the adhesive part to induce adhesion of the solder powder, and thermally melting the attached solder powder to form a circuit. The method of attaching the solder powder comprises the steps of treating the exposed metal surface of the electronic circuit board with a tackifying compound to impart tack to the metal surface to form an adhesive portion, and supplying the solder powder slurry suspended in liquid to the adhesive portion by Inducing the adhesion of the solder powder, and supplying a solder powder slurry to the portion to induce adhesion of the solder powder when the portion of the resultant electronic circuit board lacking the adhesion of the solder powder occurs. do.

Description

TECHNICAL FOR ATTACHMENT OF SOLDER POWDER AND METHOD OF MANUFACTURING SOLDERED ELECTRONIC CIRCUIT BOARD

The present invention relates to a method of restrictively attaching solder powder only to exposed fine metal surfaces (including printed wiring boards) of an electronic circuit board, to melting and exposing the solder powder for the purpose of mounting electronic components on the electronic circuit board. A method of forming a solder layer on a metal surface, and an electronic circuit board having a solder precoat formed thereon.

Recently, electronic circuit boards such as electronic circuit boards having electronic circuit patterns formed on insulating substrates such as plastic substrates (possible to include films), ceramic substrates, or metal substrates coated with plastic materials have been developed, and ICs on power distribution surfaces have been developed. BACKGROUND OF THE INVENTION A method of constructing an electronic circuit by soldering electronic components such as devices, semiconductor chips, resistors, and capacitors has been widely adopted.

In this case, the purpose for coupling the lead terminals of electronic components to a given portion of a given circuit pattern generally has a solder precoat preformed on the conductive circuit electrode (metal) surface exposed on the electronic circuit board, and the solder thereon This is accomplished by printing a paste or flux, positioning a predetermined electronic component, and then the solder precoat is reflowed alone or in combination with the solder paste to solder the relevant components.

In recent years, the trend of electronic products for miniaturization has urged the use of fine pitches in such electronic circuits. Some of the fine pitch, for example, QFP (Quad Flat Package) LSI and Chip Size Package (CSP) using 0.3 mm pitch, FC (Flip Chip) using 0.15 mm pitch, Multi Chip Module (MCM), SiP (System in Package), PoP (Package on Package) and 3DP (3 Dimensional Package) are installed in a small area. Thus, the electronic circuit board is required to have a fine solder circuit pattern corresponding to this fine pitch.

To form the solder precoat on the electronic circuit board, a plating method, a hot air leveler (HAL) method, or a method comprising printing a paste of solder powder and reflowing the produced printed material is followed. . However, the method of manufacturing the solder circuit by the plating technique is difficult to provide the thickness required for the solder layer. The HAL method and the method depending on printing the solder paste cause difficulties in the correspondence of fine pitch patterns.

Therefore, as a method for forming a solder precoat on the electronic circuit board without requiring troublesome operation such as alignment of a circuit pattern, etc., a tackifying compound is allowed to react with the surface of the conductive circuit electrode of the electronic circuit board so as to react with the surface. A method is disclosed which includes providing adhesion to a resultant, attaching solder powder to a resultant adhesive portion, and then heating the electronic circuit board to melt the solder and form a solder precoat (e.g., See JP-A HEI 7-7244).

According to the method disclosed in JP-A HEI 7-7244, the solder precoat is formed on a fine electronic circuit pattern by a simple operation, and as a result, an electronic circuit board with high reliability can be formed. However, this method attaches dry solder powder to the electronic circuit board, as a result of which the powder inevitably adheres to an unnecessary portion other than the necessary portion, and also excessively adheres on the exposed metal surface of the electronic circuit board. Therefore, a means for preventing the accumulation of static electricity is required. The deposition of solder by the dry technique disperses the powder and prevents the use of fine pitch in the electronic circuit board. The fact that the excessively adhered solder powder is not easily recovered by the drying treatment prevents the effective use of the solder powder. This problem is particularly noticeable when the solder powder used is a fine powder.

The exposed metal surface (conductive circuit electrode surface) on the electronic circuit board is treated with a tackifying compound to impart tack to the metal surface, and a solder powder is attached to the obtained adhesive part, and then the electronic circuit board is heated to In the method of manufacturing an electronic circuit board by melting solder and forming a solder precoat, the present invention provides a method of strongly adhering the solder powder to the adhesive portion, followed by a method of performing antistatic means, and the amount of solder powder adhered. A method of increasing the solder powder, the method of attaching the solder powder to realize the finer circuit pattern, the method of reusing the solder powder in a state that is not obviously degraded after the initial deposition, and the solder is sufficiently attached If not, how to correct the adhesion of the solder powder to the electronic circuit board It aims to provide.

MEANS TO SOLVE THE PROBLEM The present inventors completed this invention after diligent effort and research in terms of solving the said problem.

According to a first embodiment of the present invention, an exposed metal surface of an electronic circuit board is treated with a tackifying compound to impart adhesion to the metal surface to form an adhesive portion, and a solder powder slurry suspended in a liquid on the adhesive portion. It provides a method of attaching the solder powder comprising the step of supplying to induce the attachment of the solder powder.

A second embodiment of the present invention provides the above method described in the first embodiment, wherein the liquid used in the solder powder slurry is deoxygenated water or water to which rust inhibitor is added.

A third embodiment of the present invention includes the method for attaching the solder powder according to the first or second embodiment, wherein the electronic circuit board is immersed in a liquid or the liquid is sprayed to remove an excessively adhered solder powder. It provides a method for removing the solder powder previously attached by the.

A fourth embodiment of the present invention provides the method described in the third embodiment, wherein the liquid used in the removal of the solder powder is deoxygenated water or water to which a rust inhibitor is added.

A fifth embodiment of the present invention provides the method described in the third or fourth embodiment, wherein the excessively adhered solder powder imparts vibration to the electronic circuit board or the liquid used for immersion. It is removed by giving vibration to it.

A sixth embodiment of the present invention provides the method described in the fifth embodiment, wherein the vibration used in the removal of the excessively adhered solder powder is an ultrasonic vibration applied to the electronic circuit board, or an ultrasonic wave. It comes from a liquid imparted with vibration.

In a seventh embodiment of the present invention, the solder powder removed by the method for removing the solder powder according to any one of the third to sixth embodiments is recovered in a slurry form, and the solder powder recovered in the slurry form. It provides a method for attaching the solder powder comprising the step of supplying to the adhesive portion of the electronic circuit board.

In an eighth embodiment of the present invention, an exposed metal surface of an electronic circuit board is treated with a tackifying compound to impart tack to the metal surface to form an adhesive portion, and a solder powder slurry suspended in a liquid is supplied to the adhesive portion. Attachment of the solder powder is induced, and the method of manufacturing a soldering electronic circuit board comprising the step of thermal melting the attached solder powder to form a circuit.

9th Embodiment of this invention provides the soldering electronic circuit board manufactured using the manufacturing method of the said soldering electronic circuit board as described in said 8th Embodiment.

In a tenth embodiment of the present invention, an exposed metal surface of an electronic circuit board is treated with a tackifying compound to impart tack to the metal surface to form an adhesive portion, and a solder powder slurry suspended in a liquid is supplied to the adhesive portion. Inducing adhesion of the solder powder, and when a portion of the resulting electronic circuit board lacks adhesion of the solder powder occurs, supplying a solder powder slurry to the portion to induce the adhesion of the solder powder. Provided is a method for attaching solder powder.

By the method of attaching the solder powder according to the present invention and the manufacturing method of the electronic circuit board by the use thereof, by a simple operation, a fine solder circuit pattern exhibiting high strength of adhesion of the solder powder without any problem from static electricity is induced. And the recovered solder powder can be reused. In particular, they can bring about the effect of reducing the short circuit caused by the solder metal between adjacent circuit passages even in fine circuit patterns, and can significantly enhance the reliability of the electronic circuit board. In addition, the manufacturing method of the electronic circuit board according to the present invention makes it possible to realize miniaturization and high reliability of the circuit board on which the electronic component is mounted, and to supply an electronic device having excellent characteristics.

These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the description set forth herein below with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the sticking method of the solder powder devised by this invention.

The electronic circuit board of the present invention is, for example, a substrate having a metal plate laminated on a plastic substrate, a plastic film substrate, a glass fiber substrate, a paper matrix epoxy resin substrate, a wafer or a ceramic substrate, or a plastic or ceramic Single-sided electronic circuit boards, double-sided electronic circuit boards, multilayer electronic circuit boards, and flexible electronic circuit boards having a circuit pattern formed of a metal or other conductive material on an insulating substrate having a metal matrix coated with the substrate.

The present invention treats the surface of the conductive circuit electrode of the electronic circuit board with a tackifying compound to impart adhesion to the surface of the electrode, attaches solder powder to the obtained adhesive portion, and completely avoids problems caused by static electricity of the solder powder. The present invention relates to a method for attaching solder powder by making it adhere firmly in a fine pattern, and increasing the adhesion strength of the solder powder to the adhesive portion, wherein an electronic circuit board having the solder powder attached thereto is placed in a liquid and is unnecessary. A method of manufacturing a solder electronic circuit board by removing a portion or excessive amount of solder powder attached thereto, and then heating the electronic circuit board to melt the adhered solder powder and form a solder circuit.

In most cases, copper is used as the exposed conductive material for forming a circuit, but the present invention does not need to limit the material to only copper, but is a conductive metal material that has a tack on the surface by the tackifying compound described below. Is required. As specific examples of the material of this detailed description, metals including Ni, Sn, Ni-Au and solder alloys may be mentioned.

As a tackifying compound which can be preferably used in the present invention, naphthotriazole derivatives, benzotriazole derivatives, imidazole derivatives, benzimidazole derivatives and mercaptobenzothiazole compounds described in JP-A HEI 7-7244 Derivatives and benzothiazole thio fatty acids may be mentioned. Although these tackifying compounds exhibit a particularly strong effect on copper, they can impart tack to other conductive materials.

The present invention provides a solution of about one or more of the above-mentioned tackifying compounds, dissolves it in water or acidic water, and uses the obtained solution before applying the tack to the surface of the conductive circuit electrode on the electronic circuit board. Adjust to weak acidity of pH 3 ~ 4. As a specific example of the material used for the pH adjustment, since the conductive circuit electrode is made of metal, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid may be mentioned. Organic acids that can also be used are formic acid, acetic acid, propionic acid, malic acid, oxalic acid, succinic acid and tartaric acid. Although the concentration of the tackifying compound is not strictly limited, it is appropriately adjusted according to the solubility or use conditions of the compound. Preferably, the concentration within the range of 0.05% by mass to 20% by mass as a whole facilitates use. When it is shorter than the lower limit of this range, the deficiency suppresses the sufficient formation of the adhesive film and is detrimental to the performance.

It is preferable that the said processing temperature is slightly higher than room temperature for the said formation rate and the formation amount of an adhesion film. Although it is not limited, it can change according to the density | concentration of the said tackifying compound and the kind of said metal, and generally, the inside of the range of about 30 to 60 degreeC is preferable. Although the treatment time is not limited, it is advantageous for the efficiency of the operation that the treatment time is within the range of 5 seconds to 5 minutes by adjusting the pH, the concentration of the tackifying compound, the treatment temperature, and other conditions. .

In this case, the presence of copper (monovalent or divalent) at an ion concentration of 100 to 1000 ppm in the solution is advantageous for enhancing the formation efficiency of the pressure-sensitive adhesive film such as formation rate or amount.

The electronic circuit board to be treated is coated with a resist on which the conductive circuit portion which does not require solder other than the conductive circuit electrode surface portion to be soldered on the electronic circuit board is exposed to the conductive circuit electrode portion of the circuit pattern (exposed on the substrate). Metal surface only) is exposed and then treated with a solution of the tackifying compound.

In this regard, when the electronic circuit board coated with the resist is immersed in a solution of the tackifying compound, or when the electronic circuit board is coated or sprayed with the solution, tack is imparted to the conductive circuit electrode surface.

As a specific example of the metal composition of the said solder powder used for the manufacturing method of the said electronic circuit board which concerns on this invention, Sn-Pb system, Sn-Pb-Ag system, Sn-Pb-Bi system, Sn-Pb-Bi- Ag-based and Sn-Pb-Cd-based compositions may be mentioned. From the recent viewpoint of excluding Pb due to industrial waste, Sn-In, Sn-Bi, In-Ag, In-Bi, Sn-Zn, Sn-Ag and Sn-Cu containing no Pb Sn-Sb, Sn-Au, Sn-Bi-Ag-Cu, Sn-Ge, Sn-Bi-Cu, Sn-Cu-Sb-Ag, Sn-Ag-Zn, Sn -Cu-Ag-based, Sn-Bi-Sb-based, Sn-Bi-Sb-Zn-based, Sn-Bi-Cu-Zn-based, Sn-Ag-Sb-based, Sn-Ag-Sb-Zn-based, Sn-Ag -Cu-Zn-based and Sn-Zn-Bi-based compositions prove to be particularly preferred.

The electronic circuit board of the present invention is particularly preferably used from solders containing no Pb among other solder powders of the various compositions listed above, particularly preferably Sn and Zn or Sn, Zn and Bi, or Sn and Ag or Sn, Ag and When manufactured by using an alloy composition selected from the solder containing Cu, the components mounted on the substrate can be extended in life and can be diversified.

Regarding the particle diameter of the solder powder, Japanese Industrial Standard (JIS) is embodied in such a range as 53 to 22 µm, 45 to 22 µm and 38 to 22 µm determined by sifting. In order to determine the average particle diameter of the said solder powder of this invention, the method of using a standard body and a balance may be generally used as a prescription | regulation by JIS. It is also possible to perform image analysis with a Coulter counter according to the microscope or electron domain method for the determination. "Powder Technology Handbook" (edited by the Society of Powder Technology, Japan, 2 nd edition, pp.19-20) The principle of the Coulter counter is indicated in the said powder dispersed through the pores opened in the partition wall solution is passed It is intended to determine the particle diameter distribution of a given powder by measuring the change in electrical resistance on the opposite side of the pores. It can determine the number ratio of particle diameter with high reproducibility. The average particle diameter of the solder powder of the present invention can be determined by using the above method.

In the present invention, the adhesion of the solder powder to the electronic circuit board provided with adhesiveness in advance is intended to avoid the problem caused by static electricity. This is done by supplying to the given surface. In this case, the slurry of the solder powder will not limit its supply direction toward the tackified surface of the electronic circuit board.

However, in order to increase the adhesion thickness of the solder powder and to increase the strength of such adhesion, it is preferable that the slurry is supplied approximately perpendicular to the tackified surface of the electronic circuit board. 1 illustrates the method of attaching the solder powder according to the present invention. Specifically, this supply raises the tackified surface 4 of the electronic circuit board 3 and selectively removes a slurry of solder powder 2 from above using a method such as a dropping pipette. By providing. It is presumed that the solder powder is fed perpendicular to the pressure-sensitive adhesive portion and makes strong contact with the pressure-sensitive adhesive portion. Of course, the solder powder may be adhered to the adhesive portion to the extent necessary even by supplying the slurry of the solder powder in parallel to the surface to which the adhesiveness of the electronic circuit board is given. However, in this case, the strength of such adhesion is lowered compared with the case where the slurry is fed vertically.

In addition, although the slurry is supplied using the same method as the dropping pipette of FIG. 1, it may be continuously supplied from the storage tank to the tackified surface of the electronic circuit board using a nozzle. It is preferable that a vibration in the range of 0.1 Hz to several hundred Hz or in the range of several hundred Hz to several thousand Hz is supplied to the electronic circuit board at the time of or after the adhesion of the solder powder.

The concentration of the solder powder in the slurry is preferably high enough to allow a range within which the solder powder retains fluid. In order that the solder powder can be easily settled and blocking can be avoided, this concentration advantageously used is no more than 80% of the concentration (critical concentration) limited by fluidity, preferably about 30-50%. The critical concentration varies greatly depending on the shape and size of the solder particles, the flow rate of the slurry, the viscosity and the vibration of the liquid, and can be easily tested, so that the critical concentration under use conditions can be easily checked or blocked. It is necessary to confirm in advance the conditions to be induced.

The electronic circuit board to which the solder powder is attached is then subjected to the removal of excess solder powder in the liquid, so that during the removal, the solder powder is attached by static electricity at a portion lacking adhesion or the solder powder is electrostatically charged. Prevents agglomeration and enables the use of fine pitch or solder fine powder circuit boards.

When the step of adhering the solder powder is carried out by a dry technique, for example, the electronic circuit board which uses a plastic substrate and is often charged with static electricity is excessively soldered to the plastic substrate after the solder powder is attached. Static electricity is often generated while rubbing with a brush to remove powder. When the said solder powder is solder fine powder, it adheres also in the part in which adhesiveness provision was prevented in many cases. As a result, the solder powder adheres to unnecessary portions and induces short circuits between adjacent circuit lines in the circuit pattern. The present invention solves this problem, i.e., the problem caused by static electricity, by removing excess solder powder in the liquid.

In order to suppress static from causing problems, the present invention uses water or a mixed solvent of water and a water-soluble low boiling point organic solvent as the liquid used in the solder powder slurry. Water is proved to be preferable in consideration of problems such as environmental pollution. In this case, in order to prevent the solder powder from being oxidized by oxygen dissolved in the liquid, the water is preferably in the form of deoxygenated water or water to which a rust inhibitor is added.

In particular, where reuse of the solder powder is contemplated, it proves advantageous to prevent the deoxygenated water and / or the rust preventive water from being oxidized by oxygen dissolved in the solder powder. As the deoxygenated water, water degassed by heating or water in which an inert gas such as carbon dioxide, nitrogen or argon is bubbled can be used. When the deoxygenated water and / or the rust-prevented water is used, the surface of the removed solder powder remains protected from oxidation, which proves convenient for the purpose of reusing the solder powder. The use of such rust inhibitors requires subsequent washing with water, so that simple use of deoxygenated water proves particularly desirable.

The present invention removes excess solder powder which is done by immersing the electronic circuit board in the liquid or injecting the liquid. The removal of the excessive solder powder may be performed by gently rubbing the surface of the electronic circuit board with a brush in the liquid, but the electronic circuit board may be subjected to vibration in the range of 0.1 Hz to several hundred Hz, or in the range of several hundred kHz to several thousand kHz. Or it is preferable to carry out by providing to the said solder removal liquid. Upon removal of the solder powder from the liquid, the solder powder removed with the solder removal liquid is easily settled and can be easily recovered without inducing scattering.

In order to prevent the solder powder used in the present invention from oxidizing, it is proved to be a preferred method to coat the surface of the solder powder. The coating agent for the solder powder is selected from the group consisting of benzothiazole derivatives, amine-containing alkyl groups having 4 to 10 carbon atoms in the side chain, thiourea, silane coupling agents, lead, tin, gold, inorganic acid salts and organic acid salts. It is preferable to use at least 1 sort. As the organic acid salt, it is preferable to use at least one selected from the group consisting of lauric acid, myristic acid, palmitic acid and stearic acid.

The processing method of the present invention can be efficiently used to form bumps used to combine components of the ball grid array chip size package (BGACSP) and FC as well as the solder precoat circuit board. These devices are naturally included in the electronic circuit board of the present invention.

Then, the electronic circuit board having the solder powder removed from the excess solder powder and attached to their adhesive portion is dried, and then the ripple which heats and melts the attached solder powder and becomes the solder electronic circuit board. The rowing step is performed. Since such heating is only required for melting the solder powder attached to the adhesive portion, the treatment temperature and the treatment time can be easily determined in consideration of the melting point of the solder powder.

Since the excess solder powder removed from the electronic circuit board in the liquid can be easily separated from the solder removal liquid, it is collected and recovered and does not directly, i.e., dry, the solder powder slurry for the attachment step of the solder powder. To be used as:

The solder powder slurry is also used in the general deposition step of the solder powder by the use of such means of feeding by liquefying the solder powder from the bottom until it is extruded into the pump and overflowed. In addition, as the means for supply, means in the form of a small dropping pipette may be used.

When a portion lacking solder adhesion occurs after the electronic circuit board is subjected to general soldering treatment, the portion is provided with adhesiveness by treating with a tackifying compound, and the obtained adhesive portion is provided with the solder by using a supply means such as a dropping pipette. Powder slurry is provided. When the electronic circuit board is treated with a tackifying compound to provide adhesiveness and a portion lacking the solder adhesion occurs after the solder powder adheres to the obtained adhesive portion, by using a supply means in the form of a small dropping pipette The solder powder slurry is fed. These means may be used to repair and modify the solder circuit.

The solder electronic circuit board manufactured by the present invention can be advantageously used in a method of mounting an electronic component comprising the step of joining the electronic component by positioning the electronic component and causing reflow of the solder. For example, the solder precoat is formed on the electrode of the electronic circuit board according to the present invention, where the solder paste is applied by the printing technique, and the electronic component (chip part, CSP, etc.) is the solder Mounted on a paste, the reflow heat source is acted in batches to effect solder bonding. As the reflow heat source, a hot air oven, an infrared heating furnace, a condensation soldering device, a light beam soldering device, or the like can be used.

If the electrode uses a pitch that is too fine to apply the solder paste by printing, the bonding of the electronic component to the circuit board prints a tacky flux on the electrode, which is pre-provided with a solder precoat, on which the electron By mounting a component (semiconductor chip, etc.) or by supplying the adhesive flux to the bump on the electronic component, mounting the electronic component on the electrode provided with a solder precoat in advance, and then causing a reflow of the relevant component This can be done by.

The method also includes forming Au bumps (stud bumps) on the electrodes of the semiconductor chip and combining these Au bumps with the solder precoats formed on the electrodes of the circuit board by applying pressure and heat. Mounting of a semiconductor chip such as a method including supplying a non-conductor resin in the form of a paste or sheet onto the circuit board and applying pressure and heat to cause a thermocompression bonding of a semiconductor chip having an Au bumper formed on their electrodes The method is also used efficiently.

The reflowing process devised by the present invention changes depending on the composition of the solder alloy. In the case of Sn-Zn-based alloys such as 91Sn / 9Zn, 89Sn / 8Zn / 3Bi, and 86Sn / 8Zn / 6Bi, the above process is preferably performed in two steps, preheating and reflowing. Regarding these two-stage conditions, the preheating temperature is in the range of 130 to 180 ° C, preferably 130 to 150 ° C, and the preheating time is in the range of 60 to 120 seconds, preferably 60 to 90 seconds. The reflowing temperature is in the range of 210 to 230 ° C, preferably 210 to 220 ° C, and the reflowing time is in the range of 30 to 60 seconds, preferably 30 to 40 seconds. The said reflowing temperature of another alloy system is in the range of +20-+50 degreeC with respect to melting | fusing point of the alloy used, Preferably it is +20-+30 degreeC. The other preheating temperature, preheating time and reflowing time may be in the same range as described above.

The reflowing process can be done in nitrogen or air. In the case of nitrogen reflow, when the oxygen concentration is adjusted to 5 or less apparent volume, preferably 0.5 or less, the wettability represented by the solder to the solder circuit is enhanced and the occurrence of solder balls is reduced. The process can therefore be stabilized as compared to the case of open air reflow.

Example 1:

A printed wiring board with a minimum electrode spacing of 50 μm was produced. Copper was used in the conductive circuit. As a tackifying compound solution, following General formula (1)

The aqueous solution of 2% by mass of imidazole compound represented by was used after adjusting the pH value to about 4 with acetic acid. The aqueous solution was heated to 40 ° C. In the heated aqueous solution, the printed wiring board preheated with aqueous hydrochloric acid solution was immersed for 3 minutes to have a tacky material formed on the surface of the copper circuit.

Subsequently, a slurry formed by dispersing 96.5Sn / 3.5Ag solder powder having an average particle diameter of about 20 μm at a concentration of 50 vol% in deoxygenated water was supplied onto the printed wiring board using the apparatus shown in FIG. The printed wiring board was exposed to vibration of 50 Hz to induce adhesion of the solder powder to the substrate. After the printed wiring board was weakly vibrated and washed in the deoxygenated water, as a result, the printed wiring board with solder powder adhered was dried.

After the flux was supplied by spraying, the printed wiring board was placed in an oven at 240 ° C. and heated to melt the solder powder and have a thickness of 96.5Sn / 3.5Ag solder free having a thickness of about 20 μm on the exposed portion of the copper circuit. A coat was formed. In addition, the average particle diameter of the said solder powder was determined by the use of MICROTRAC ^® . The solder circuit produced no bridges at all.

Example 2:

A printed wiring board having an area array using an electrode diameter of 70 μm and an electrode spacing of 60 μm was manufactured. Copper was used as the conductive circuit.

As a tackifying compound solution, a 2 mass% aqueous solution of this imidazole compound was adjusted to pH 4 with acetic acid as used in Example 1 and used. The aqueous solution was heated to 40 ° C. In the heated aqueous solution, the printed wiring board preheated with aqueous hydrochloric acid solution was immersed for 3 minutes to have a tacky material formed on the surface of the copper circuit.

Subsequently, a slurry formed by dispersing 96.5Sn / 3.5Ag solder powder having an average particle diameter of about 60 μm in a deoxygenated water at a concentration of 50% by volume was supplied onto the printed wiring board using the apparatus shown in FIG. The printed wiring board was exposed to vibration of 50 Hz. After the printed wiring board was slightly vibrated and washed in the deoxygenated water, the obtained printed wiring board was dried.

After the flux was supplied by spraying, the printed wiring board was placed in an oven at 240 ° C. and heated to melt the solder powder.

On this exposed portion of the copper circuit, 96.5Sn / 3.5Ag solder bumps having a thickness of about 40 μm were formed.

Excellent bumps were formed on the solder circuit, and no defects such as bridges and portions out of bumps were formed.

Imparting tack to the exposed metal portions on the substrate, attaching solder powder to the resulting adhesion, then removing excess adhered solder powder from the liquid, and from removing excessively adhered solder powder The method of manufacturing a soldering electronic circuit board provided with a solder precoat on their electrodes by heating the obtained electronic circuit board to melt the solder powder obtains the effect of reducing short circuit caused by solder metal between adjacent circuit lines even in a fine circuit pattern. To enable the manufacture of soldering electronic circuit boards with significantly improved reliability.

As a result, miniaturization of a circuit board equipped with a highly reliable electronic component having a fine circuit pattern can be realized, and an electronic circuit board, a circuit board equipped with an electronic component capable of realizing high reliability and high mounting density, and characteristics This excellent electronic device can be provided, and the method of the present invention can be applied to the manufacture of an electronic device.

The recovered excess solder powder can be recovered and reused in the attachment step of the solder powder, so that the utilization rate of the solder powder can be enhanced.

Claims (11)

Treating the exposed metal surface of the electronic circuit board with a tackifying compound to impart tack to the metal surface to form an adhesive portion; And Supplying the solder powder slurry with a solder powder suspended in a concentration of 30 to 50% to deoxygenated water or water to which a rust inhibitor is added to induce adhesion of the solder powder; And Immersing the electronic circuit board in deoxygenated water or rust-prevented water or spraying deoxygenated water or rust-prevented water to remove the excessively adhered solder powder. . 2. The method of claim 1, wherein the solder powder slurry is fed perpendicular to an adhesive portion of an exposed metal surface of the electronic circuit board. delete delete delete The method of claim 1, wherein the excessively adhered solder powder is removed by applying vibration to the liquid used in the electronic circuit board or its immersion. 7. The method for attaching solder powder according to claim 6, wherein the vibration used in the removal of the excessively adhered solder powder is derived from ultrasonic vibration imparted to the electronic circuit board or liquid imparted with ultrasonic vibration. . delete Treating the exposed metal surface of the electronic circuit board with a tackifying compound to impart tack to the metal surface to form an adhesive portion; Supplying the solder powder slurry with a solder powder suspended in a concentration of 30 to 50% to deoxygenated water or water to which a rust inhibitor is added to induce adhesion of the solder powder; Immersing the electronic circuit board in deoxygenated water or rust-prevented water or spraying deoxygenated water or rust-prevented water to remove excess adhered solder powder; And And thermally melting the attached solder powder to form a circuit. delete delete

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