US20040144829A1 - Method of soldering lead-free solder, and joined object soldered by the soldering method - Google Patents
Method of soldering lead-free solder, and joined object soldered by the soldering method Download PDFInfo
- Publication number
- US20040144829A1 US20040144829A1 US10/759,191 US75919104A US2004144829A1 US 20040144829 A1 US20040144829 A1 US 20040144829A1 US 75919104 A US75919104 A US 75919104A US 2004144829 A1 US2004144829 A1 US 2004144829A1
- Authority
- US
- United States
- Prior art keywords
- lead
- free solder
- soldering
- joining
- ultrasonic vibration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229910000679 solder Inorganic materials 0.000 title claims abstract description 146
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000005476 soldering Methods 0.000 title claims abstract description 39
- 230000008018 melting Effects 0.000 claims abstract description 40
- 238000002844 melting Methods 0.000 claims abstract description 40
- 239000013078 crystal Substances 0.000 claims abstract description 23
- 229910001128 Sn alloy Inorganic materials 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 claims description 23
- 230000007423 decrease Effects 0.000 claims description 19
- 150000001875 compounds Chemical class 0.000 claims description 17
- 229910020836 Sn-Ag Inorganic materials 0.000 claims description 15
- 229910020988 Sn—Ag Inorganic materials 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 229910045601 alloy Inorganic materials 0.000 claims description 8
- 239000000956 alloy Substances 0.000 claims description 8
- 238000005204 segregation Methods 0.000 claims description 7
- 229910052797 bismuth Inorganic materials 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 6
- 229910052738 indium Inorganic materials 0.000 claims description 6
- 239000002075 main ingredient Substances 0.000 claims description 5
- 229910052725 zinc Inorganic materials 0.000 claims description 4
- 230000006866 deterioration Effects 0.000 abstract description 2
- 229910020888 Sn-Cu Inorganic materials 0.000 description 9
- 229910019204 Sn—Cu Inorganic materials 0.000 description 9
- 230000005496 eutectics Effects 0.000 description 9
- 238000002474 experimental method Methods 0.000 description 9
- 239000010949 copper Substances 0.000 description 7
- 229910020994 Sn-Zn Inorganic materials 0.000 description 6
- 229910009069 Sn—Zn Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 235000019589 hardness Nutrition 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 229910020816 Sn Pb Inorganic materials 0.000 description 2
- 229910020830 Sn-Bi Inorganic materials 0.000 description 2
- 229910020922 Sn-Pb Inorganic materials 0.000 description 2
- 229910018728 Sn—Bi Inorganic materials 0.000 description 2
- 229910018956 Sn—In Inorganic materials 0.000 description 2
- 229910008783 Sn—Pb Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- QCEUXSAXTBNJGO-UHFFFAOYSA-N [Ag].[Sn] Chemical compound [Ag].[Sn] QCEUXSAXTBNJGO-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- JWVAUCBYEDDGAD-UHFFFAOYSA-N bismuth tin Chemical compound [Sn].[Bi] JWVAUCBYEDDGAD-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- YZASAXHKAQYPEH-UHFFFAOYSA-N indium silver Chemical compound [Ag].[In] YZASAXHKAQYPEH-UHFFFAOYSA-N 0.000 description 1
- RHZWSUVWRRXEJF-UHFFFAOYSA-N indium tin Chemical compound [In].[Sn] RHZWSUVWRRXEJF-UHFFFAOYSA-N 0.000 description 1
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- GZCWPZJOEIAXRU-UHFFFAOYSA-N tin zinc Chemical compound [Zn].[Sn] GZCWPZJOEIAXRU-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
- B23K1/06—Soldering, e.g. brazing, or unsoldering making use of vibrations, e.g. supersonic vibrations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
- B23K1/20—Preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3457—Solder materials or compositions; Methods of application thereof
- H05K3/3463—Solder compositions in relation to features of the printed circuit board or the mounting process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/36—Electric or electronic devices
- B23K2101/40—Semiconductor devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/36—Electric or electronic devices
- B23K2101/42—Printed circuits
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
Definitions
- FIG. 3 is a conceptual diagram for explaining a state of crystals of contained components of the lead-free solder at a joining part between an electrode of a printed board and an electronic component when the ultrasonic vibration is acted in the soldering method of FIG. 1;
- the vibration may be acted intermittently.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
There are provided a method of soldering a lead-free solder which lowers a melting point of the lead-free solder and prevents deterioration of a joining strength at a portion joined by the lead-free solder, and a joined object soldered with the use of the soldering method. The lead-free solder as an alloy of tin with no lead contained is melted, and ultrasonic vibration is acted at least either to the join object to be joined by the lead-free solder or to the lead-free solder when the molten lead-free solder is solidified. Therefore crystals of contained components in the lead-free solder are made fine and the contained components are prevented from being segregated at a joining interface of the joined object, so that the joining strength at the joining interface can be increased.
Description
- The present invention relates to a soldering method using a solder with no lead contained, that is, a lead-free solder, and a joined object soldered with the use of the soldering method.
- In view of environmental protection and since lead included in solder based on Sn—Pb (tin-lead) used heretofore for fixing electronic components onto printed boards has a bad influence on not only the environment, but human bodies, solders not containing the lead, namely, lead-free solders have been under development lately. At present, the lead-free solders based on Sn—Cu (tin-copper), Sn—Ag (tin-silver), Sn—Zn (tin-zinc), Sn—Bi (tin-bismuth), Sn—In (tin-indium), In—Ag (indium-silver), etc. have been developed, and particularly the Sn—Cu based, Sn—Ag based and Sn—Zn based types have potentialities.
- However, in comparison with a melting point, i.e., 183° C. of a conventional eutectic solder based on Sn—Pb containing lead, a lead-free solder of a composition, for example, of Sn-0.7Cu in the Sn—Cu has a melting point of 227° C., the Sn—Ag based lead-free solder in a composition of, e.g., Sn-3.5Ag has a melting point of 221° C., and the Sn—Zn based lead-free solder of a composition of, e.g., Sn-8Zn has a melting point of 199° C. Although the melting point of the Sn—Zn based type is lowest among these solders, since Zn is easy to oxidize and no effective means is found at present for preventing the oxidation, the Sn—Zn based lead-free solder involves problems to be solved before used to fix electronic components onto a printed board as described hereinabove. Under the circumstances, the potential lead-free solder now is the Sn—Cu based type and the Sn—Ag based type, but both of which have higher melting points by approximately 40° C. than that of the eutectic solder.
- A heat resistant temperature of general electronic components is approximately 230° C. Therefore, a thermal allowance of approximately 50° C. is provided when the conventional eutectic solder is used to fix electronic components onto the printed board. However, the thermal allowance almost disappears in using, e.g., the Sn—Cu based and Sn—Ag based lead-free solders for the fixing. The thermal allowance is still more extreme for components weakly resistant to heat such as, for instance, aluminum electrolytic capacitors and the like.
- For decreasing the melting points of the lead-free solders to or lower than the melting point of the conventional eutectic solder as much as possible, there is proposed lead-free solders in composition of, e.g., Sn-3.5Ag-6Bi, Sn-3.5Ag-3Bi-3In and the like having Bi (bismuth), In (indium) and the like added as a melting point decrease action metal acting to decrease the melting point.
- The conventional eutectic solder changes almost instantaneously from a melt state to a solid state. On the other hand, the melting point of the lead-free solder decreases in proportion to an added amount of Bi when the Bi is added to the lead-free solder. But, when, for example, the Bi is added to the lead-free solder, a temperature range in which the lead-free solder changes from a melt state to a solid state expands as compared with that of the conventional eutectic solder. As a result, during solidification of the lead-free solder, the lead-free solder is brought into a state in which a partially solidified part and a part still in the melt state mix. Consequently, crystals of, e.g., Bi growing large in the lead-
free solder 4 may segregation at a joiningpart 3 between anelectronic component 1 and anelectrode 2 of a printedboard 5 as shown in FIG. 8. An enlarged illustration of the joining part in FIG. 8 diagrammatically shows a composition of the lead-free solder 4 at the joiningpart 3, in which a symbol “◯” corresponds to, e.g., Bi and a symbol “□” corresponds to., e.g., Ag. A symbol “Δ” shown at a joining interfacial part to theelectrode 2 corresponds to a compound of Cu as a material of theelectrode 2 and Sn in the lead-free solder. - Meanwhile, Bi itself has a higher hardness than hardnesses of Sn and Ag. Therefore a strength of the lead-free solder at a part where Bi gathers due to the segregation of Bi crystals becomes brittle when the Bi is included by, e.g., several tens wt. % in the lead-free solder. A joining strength at the joining interfacial part decreases if the Bi crystals are unevenly distributed and then solidified at the joining interfacial part of the
electrode 2, leading to the trouble that a sufficient joining strength cannot be obtained between theelectrode 2 and theelectronic component 1. A content of Bi at present is hence unavoidably limited to several wt. % from a view point of a reliability on the joining strength, and therefore the melting point cannot be sufficiently lowered at present. Since the melting point of the present lead-free solder is higher than the melting point of the eutectic solder as depicted above, for example, a larger power is inevitably required for melting the solder than when the eutectic solder is used, thereby raising problems in view of costs and saving energy. Further components of a low thermal resistance cannot be soldered with the use of the lead-free solder. - The present invention is devised to solve the above-described problems and has for its object to provide a method of soldering a lead-free solder which lowers a melting point of the lead-free solder and prevents deterioration of a joining strength at parts joined by the lead-free solder, and joined objects soldered with the use of the soldering method.
- In accomplishing the above and other aspects, there is provided according to a first aspect of the present invention a method of soldering a lead-free solder which comprises:
- melting the lead-free solder which is an alloy of tin with no lead contained; and
- acting ultrasonic vibration for increasing a joining strength between a mount article and a member to be mounted to at least one of the mount article and the member to be mounted which are to be joined by the lead-free solder, and the lead-free solder when solidifying the molten lead-free solder.
- The ultrasonic vibration can be such that makes crystals of components contained in the lead-free solder fine and prevents segregation of the contained components, and increases the joining strength between the mount article and the member to be mounted.
- Moreover, the ultrasonic vibration may be such that makes crystals of components contained in the lead-free solder fine and prevents segregation of the contained components at a joining interface of at least either the mount article or the member to be mounted, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
- The contained components may include a component of a melting point decrease action metal for acting to decrease a melting point of the lead-free solder.
- In the case where the mount article and the member to be mounted contain Cu, the ultrasonic vibration may be such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
- The lead-free solder may have a Sn—Ag based composition as a main ingredient.
- When the lead-free solder has the Sn—Ag based composition as the main ingredient, the above-mentioned contained components may include an alloy component of the Sn—Ag.
- The melting point decrease action metal can be at least one of Bi, Cu, Zn and In.
- A joined object according to a second aspect of the present invention is soldered with the use of the method of soldering the lead-free solder of the first aspect.
- According to the soldering method of the lead-free solder in the first aspect of the present invention, since the ultrasonic vibration is let to act when the molten lead-free solder is solidified, crystals of the components contained in the lead-free solder can be turned minute and prevented from segregating at the joining interface of at least one of the mount article and the member to be mounted which are to be joined by the lead-free solder, so that the joining strength between the mount article and the member to be mounted at the joining interface can be increased as compared with a case without the ultrasonic vibration acted.
- In the joined object soldered with the use of the above soldering method according to the second aspect of the present invention, crystals of contained components of the lead-free solder are turned minute and prevented from segregating at the joining interfaces of the joined object as above, and the joining strength at the joining interfaces is increased as compared with the case where the ultrasonic vibration is not acted. The Joined object with a high joining strength can be provided accordingly.
- These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
- FIG. 1 is a flow chart showing processes of a lead-free solder soldering method according to an embodiment of the present invention;
- FIG. 2 is a diagram for explaining a timing for acting ultrasonic vibration in FIG. 1;
- FIG. 3 is a conceptual diagram for explaining a state of crystals of contained components of the lead-free solder at a joining part between an electrode of a printed board and an electronic component when the ultrasonic vibration is acted in the soldering method of FIG. 1;
- FIG. 4 is a graph of a relationship between the presence or absence of acting the ultrasonic vibration and a tensile strength in the lead-free solder of a composition of Sn-3.5Ag-40Bi;
- FIG. 5 is a graph of a relationship between the presence or absence of acting the ultrasonic vibration and the tensile strength in the lead-free solder of a composition of Sn-3.5Ag-20Bi;
- FIG. 6 is a graph of a relationship between the presence or absence of acting the ultrasonic vibration and the tensile strength in the lead-free solder of a composition of Sn-3.5Ag-6Bi;
- FIG. 7 is a diagram for explaining a method for measuring the tensile strength; and
- FIG. 8 is a conceptual diagram for explaining a state of crystals of contained components of the lead-free solder at the joining part between the electrode of the printed board and the electronic component when the ultrasonic vibration is not acted.
- A method of soldering a lead-free solder, and a joined object soldered with the use of the soldering method according to an embodiment of the present invention will be described below with reference to the drawings. It is to be noted here that like parts are designated by like reference numerals through the accompanying drawings.
- According to the present embodiment, a printed board and an electronic component are given as examples of the joined object in the case where the electronic component as an example of a mount article is to be soldered onto the printed board as an example of a member to be mounted.
- In the present embodiment, as an example of the solder which is an alloy of tin with no lead contained, i.e., a lead-free solder, a lead-free solder in which Bi as a metal acting to lower a melting point of the lead-free solder, that is, Bi as a melting point decrease action metal is added to the above Sn—Ag based solder is taken. However, the lead-free solder is not limited to this composition and can be the earlier-described Sn—Cu based type, Sn—Zn based type, Sn—Bi based type, Sn—In based type, In—Ag based type or the like, and the melting point decrease action metal to be added can be Bi, In, Cu or the like. The melting point decrease action metal exceeds by approximately 0.5 wt. %, is not limited to a single composition of, for instance, Bi or the like and may have an alloy containing, e.g., Bi or the like.
- The method of soldering the lead-free solder has processes as shown in FIG. 1. A lead-
free solder 101 used in the soldering method has a composition of Sn—Ag-Bi. A content of Bi is set to be 20 wt. % and 40 wt. %. A maximum value of the content of Bi is 58 wt. % (Sn-58Bi) where Bi is turned to a eutectic state to Sn without Ag included. - According to the soldering method of the lead-free solder in FIG. 1, in step (designated by “S” in the drawing)1, the lead-
free solder 101 in the composition of, for example, Sn-3.5Ag-40Bi is melted. Innext step 2, for the earlier referredelectronic component 1 and printedboard 5 constituting the joined object, the lead-free solder 101 is brought in contact with apart 3 to be joined between theelectronic component 1 and anelectrode 2 on the printedboard 5. - In
next step 3, the lead-free solder 101 including the joinedportion 3 is started to be cooled. Further, an ultrasonic horn of an ultrasonic oscillator is brought into contact with the printedboard 5 so as to generate a vibration to at least the joinedportion 3. The vibration has a frequency of a level at which crystals are made fine and prevented from being unevenly distributed as will be described later, that is, for example, an amplitude of several μm. - The lead-
free solder 101 is vibrated by the ultrasonic vibration when the ultrasonic vibration is acted to the joinedportion 3. OvergrownBi crystals 31 as shown in FIG. 8 are turned fine as indicated in FIG. 3 owing to the action of the vibration and moreover the lead-free solder 101 is blended by the action of the vibration, so that Bi crystals can be prevented from being unevenly distributed, for instance, to a joining interface of theelectrode 2. In consequence, crystals of Bi having a higher hardness than hardnesses of the other components in the lead-free solder 101, e.g., Sn, Ag or the like are prevented from being segregated and solidified in a state that the crystals of Bi are gathered to, for example, the joining interface of theelectrode 2. In the case where Ag is included as components of the lead-free solder 101 of the present embodiment, although an alloy of Sn and Ag is formed and deposited, the ultrasonic vibration works to make fine crystals of this Sn—Ag alloy as well. The whole of the joinedportion 3 is hence made nearly uniform in composition and moreover, crystals in each composition are made fine. Accordingly, a strength of the entire joinedportion 3 is unified and the joining strength at the joining interface of theelectrode 2 can be enhanced in comparison with the conventional art without the ultrasonic vibration acted. - Effects as follows can be further obtained by acting the ultrasonic vibration. Specifically, although a compound of Sn and Cu included in the lead-
free solder 101 is formed to surface portions of theelectrode 2 and an electrode of theelectronic component 1 having Cu as a main ingredient as described above, a layer including the Sn—Cu compound is diffused to grow in the lead-free solder 101 by the ultrasonic vibration when the vibration is acted. The joining strength at the joining interface of theelectrode 2 can be enhanced more by acting the ultrasonic vibration so that athickness 102 of the layer including the Sn—Cu compound becomes an appropriate value. The joining strength is reversely weakened if thethickness 102 exceeds the appropriate value, and therefore the frequency and the ultrasonic vibration should be controlled. - Additionally, since a surface tension of the lead-free solder can be reduced by applying the ultrasonic vibration, a solderability can be improved and the joining strength can be enhanced.
- As above, the amplitude value and the frequency at the joined
portion 3 by the ultrasonic vibration are set to such values that components included in the lead-free solder, for example, Bi crystals as mentioned above are made fine at the joining interface of the joined object, crystals of the formed alloy such as Sn—Ag or the like are made fine, the contained components and the alloy crystals are prevented from segregating, and the joining strength of theelectrode 2 of the printedboard 5 and the electrode of theelectronic component 1 at the joining interface is increased, and furthermore, the thickness of the layer including the Sn—Cu compound present at the joining interface is increased, thereby increasing the joining strength at the joining interface and also increasing the solderability. - The ultrasonic vibration may be started to act concurrently with a time when the molten lead-
free solder 101 is started to be cooled, as designated by a time t1 in FIG. 2 or may be started prior to the start of the cooling as indicated by a time t0. The action should be started at least immediately before a temperature of the lead-free solder reaches a solidifying temperature of the lead-free solder 101, as indicated by a time t2. An end time point of the action of the ultrasonic vibration is after the lead-free solder 101 is perfectly solidified. - Although it is preferable to continuously act the ultrasonic vibration, the vibration may be acted intermittently.
- Experiments are conducted to obtain the joining strengths in the case where the ultrasonic vibration is acted as above and in the case where the ultrasonic vibration is not acted in the conventional art. A method for the experiment is shown in FIG. 7 and experiment results are shown in FIGS.4-6.
- According to the experiment method, while a lead wire of the
electronic component 1 joined to theelectrode 2 with the use of the lead-free solder is pulled in a 45° direction, separation between the lead wire and theelectrode 2 and a tensile strength at a time when the lead wire or theelectrode 2 reaches to brake are checked. FIG. 4 indicates the experiment result in the case of using the lead-free solder of a composition of Sn-3.5Ag-40Bi, while FIG. 5 shows the experiment result in the case of Sn-3.5Ag-20Bi and FIG. 6 shows the experiment result in the case of Sn-3.5Ag-6Bi. The lead-free solder of the composition of Sn-3.5Ag-40Bi has a melting point of approximately 180° C., the lead-free solder of the composition of Sn-3.5Ag-20Bi has a melting point of approximately 200° C., and the lead-free solder of the composition of Sn-3.5Ag-6Bi has a melting point of approximately 216° C. - As is apparent from the experiment results indicated particularly in FIGS. 4 and 5, the tensile strength is improved more when the ultrasonic vibration is acted than when the ultrasonic vibration is not acted. Further, as is made clear from the experiment results of FIGS. 4 and 5, and FIG. 6, the ultrasonic vibration acts effectively in the lead-free solder of a large content of Bi.
- A reliability can be obtained even in the lead-free solder with a larger content of Bi than in the conventional art owing to the action of the ultrasonic vibration as above. Hence the lead-free solder of a lower melting point than that of the conventional lead-free solder becomes utilizable, enabling, for example, components of the weak heat resistance to be fixed to the printed board or the like by the lead-free solder. The power necessary for melting the lead-free solder can be lowered than for the conventional lead-free solder, which is effective to save energy and eventually contributes to protect the environment.
- The entire disclosure of Japanese Patent
- Application No. 11-165165 filed on Jun. 11, 1999 including the specification, claims, drawings and summary is incorporated herein by reference in its entirety.
- Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
Claims (20)
1. A method of soldering a lead-free solder which comprises:
melting the lead-free solder (101) which is an alloy of tin with no lead contained; and
acting ultrasonic vibration for increasing a joining strength between a mount article (1) and a member (5) to be mounted to at least one of the mount article and the member to be mounted which are to be joined by the lead-free solder, and the lead-free solder when solidifying the molten lead-free solder.
2. The method of soldering the lead-free solder according to claim 1 , wherein the ultrasonic vibration is such that makes crystals of components contained in the lead-free solder fine and prevents segregation of the contained components, and increases the joining strength between the mount article and the member to be mounted.
3. The method of soldering the lead-free solder according to claim 1 , wherein the ultrasonic vibration is such that makes crystals of components contained in the lead-free solder fine and prevents segregation of the contained components at a joining interface of at least one of the mount article and the member to be mounted, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
4. The method of soldering the lead-free solder according to claim 2 , wherein the ultrasonic vibration is such that makes fine crystals of components contained in the lead-free solder and prevents segregation of the contained components at a joining interface of at least one of the mount article and the member to be mounted, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
5. The method of soldering the lead-free solder according to claim 2 , wherein the contained components include a component of a melting point decrease action metal for acting to decrease a melting point of the lead-free solder.
6. The method of soldering the lead-free solder according to claim 3 , wherein the contained components include a component of a melting point decrease action metal for acting to decrease a melting point of the lead-free solder.
7. The method of soldering the lead-free solder according to claim 4 , wherein the contained components include a component of a melting point decrease action metal for acting to decrease a melting point of the lead-free solder.
8. The method of soldering the lead-free solder according to claim 3 , wherein, when the mount article and the member to be mounted contain Cu, the ultrasonic vibration is such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
9. The method of soldering the lead-free solder according to claim 4 , wherein, when the mount article and the member to be mounted contain Cu, the ultrasonic vibration is such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
10. The method of soldering the lead-free solder according to claim 5 , wherein, when the mount article and the member to be mounted contain Cu, the ultrasonic vibration is such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
11. The method of soldering the lead-free solder according to claim 6 , wherein, when the mount article and the member to be mounted contain Cu, the ultrasonic vibration is such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
12. The method of soldering the lead-free solder according to claim 7 , wherein, when the mount article and the member to be mounted contain Cu, the ultrasonic vibration is such that increases a thickness of a layer of a compound of Sn included in the lead-free solder and the Cu, the compound existing at the joining interface, and increases the joining strength between the mount article and the member to be mounted at the joining interface.
13. The method of soldering the lead-free solder according to claim 1 , wherein the lead-free solder has a Sn—Ag based composition as a main ingredient.
14. The method of soldering the lead-free solder according to claim 12 , wherein the lead-free solder has a Sn—Ag based composition as a main ingredient.
15. The method of soldering the lead-free solder according to claim 13 , wherein the contained components include an alloy component of the Sn—Ag.
16. The method of soldering the lead-free solder according to claim 14 , wherein the contained components include an alloy component of the Sn—Ag.
17. The method of soldering the lead-free solder according to claim 5 , wherein the melting point decrease action metal is at least one of Bi, Cu, Zn and In.
18. The method of soldering the lead-free solder according to claim 8 , wherein the melting point decrease action metal is at least one of Bi, Cu, Zn and In.
19. The method of soldering the lead-free solder according to claim 13 , wherein the melting point decrease action metal is at least one of Bi, Cu, Zn and In.
20. A Joined object soldered with the use of the method of soldering the lead-free solder according to any one of claims 11-19.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/759,191 US20040144829A1 (en) | 1999-06-11 | 2004-01-20 | Method of soldering lead-free solder, and joined object soldered by the soldering method |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16516599A JP3580731B2 (en) | 1999-06-11 | 1999-06-11 | Lead-free solder soldering method and joined body soldered by the soldering method |
JP11-165165 | 1999-06-11 | ||
US10/009,168 US6702175B1 (en) | 1999-06-11 | 2000-06-07 | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
US10/759,191 US20040144829A1 (en) | 1999-06-11 | 2004-01-20 | Method of soldering lead-free solder, and joined object soldered by the soldering method |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/009,168 Division US6702175B1 (en) | 1999-06-11 | 2000-06-07 | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040144829A1 true US20040144829A1 (en) | 2004-07-29 |
Family
ID=15807104
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/009,168 Expired - Fee Related US6702175B1 (en) | 1999-06-11 | 2000-06-07 | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
US10/759,191 Abandoned US20040144829A1 (en) | 1999-06-11 | 2004-01-20 | Method of soldering lead-free solder, and joined object soldered by the soldering method |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/009,168 Expired - Fee Related US6702175B1 (en) | 1999-06-11 | 2000-06-07 | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
Country Status (5)
Country | Link |
---|---|
US (2) | US6702175B1 (en) |
EP (1) | EP1195217B1 (en) |
JP (1) | JP3580731B2 (en) |
DE (1) | DE60016413T2 (en) |
WO (1) | WO2000076708A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3580731B2 (en) * | 1999-06-11 | 2004-10-27 | 和美 松重 | Lead-free solder soldering method and joined body soldered by the soldering method |
US20040155097A1 (en) * | 2003-02-04 | 2004-08-12 | Matsushita Electric Industrial Co., Ltd. | Soldering method and method for manufacturing component mounting board |
JP3918779B2 (en) * | 2003-06-13 | 2007-05-23 | 松下電器産業株式会社 | Soldering method for non-heat resistant parts |
US7287685B2 (en) * | 2004-09-20 | 2007-10-30 | International Business Machines Corporation | Structure and method to gain substantial reliability improvements in lead-free BGAs assembled with lead-bearing solders |
US8220697B2 (en) * | 2005-01-18 | 2012-07-17 | Siemens Energy, Inc. | Weldability of alloys with directionally-solidified grain structure |
DE102006035626A1 (en) * | 2006-07-31 | 2008-02-07 | Zentrum für Material- und Umwelttechnik GmbH | Method for attaching a connection conductor to a photovoltaic solar cell |
JP2010142848A (en) * | 2008-12-19 | 2010-07-01 | Ijr:Kk | Brazing method and brazing apparatus |
DE102010000520A1 (en) * | 2010-02-23 | 2011-08-25 | SCHOTT Solar AG, 55122 | Method and device for applying solder to a workpiece |
US20120000964A1 (en) * | 2010-07-01 | 2012-01-05 | Gm Global Technology Operations, Inc. | Battery tab joints and methods of making |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4885841A (en) * | 1989-02-21 | 1989-12-12 | Micron Technology, Inc. | Vibrational method of aligning the leads of surface-mount electronic components with the mounting pads of printed circuit boards during the molten solder mounting process |
US5094700A (en) * | 1990-03-22 | 1992-03-10 | University Of Cincinnati | Solder and brazing alloys having improved properties and method of preparation |
US5256370A (en) * | 1992-05-04 | 1993-10-26 | The Indium Corporation Of America | Lead-free alloy containing tin, silver and indium |
US5492263A (en) * | 1994-05-26 | 1996-02-20 | Delco Electronics Corp. | Method for wire bonding an aluminum wire to a lead of an electronics package |
US5511719A (en) * | 1993-06-01 | 1996-04-30 | Nippondenso Co., Ltd. | Process of joining metal members |
US5730932A (en) * | 1996-03-06 | 1998-03-24 | International Business Machines Corporation | Lead-free, tin-based multi-component solder alloys |
US5918795A (en) * | 1996-02-09 | 1999-07-06 | Matshushita Electric Industrial Co., Ltd. | Soldering alloy, cream solder and soldering method |
US6047876A (en) * | 1997-09-12 | 2000-04-11 | Materials Resources International | Process of using an active solder alloy |
US6171415B1 (en) * | 1998-09-03 | 2001-01-09 | Uit, Llc | Ultrasonic impact methods for treatment of welded structures |
US6271601B1 (en) * | 1998-05-12 | 2001-08-07 | Hitachi, Ltd. | Wire bonding method and apparatus and semiconductor device |
US6319461B1 (en) * | 1999-06-11 | 2001-11-20 | Nippon Sheet Glass Co., Ltd. | Lead-free solder alloy |
US20020031903A1 (en) * | 2000-08-29 | 2002-03-14 | Hiroshi Yamauchi | Component mounting apparatus and method, component mounting system having the apparatus, and circuit board manufactured by the method |
US20020056741A1 (en) * | 2000-11-16 | 2002-05-16 | Shieh Wen Lo | Application of wire bonding technology on wafer bump, wafer level chip scale package structure and the method of manufacturing the same |
US6457632B1 (en) * | 1997-04-25 | 2002-10-01 | Kabushiki Kaisha Toshiba | Solder alloy and bonding method of substrate and electric or electronic parts with solder alloy |
US6702175B1 (en) * | 1999-06-11 | 2004-03-09 | Matsushita Electric Industrial Co., Ltd. | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55136562A (en) * | 1979-04-09 | 1980-10-24 | Hitachi Ltd | Ultrasonic pre-soldering method and apparatus thereof |
DE3240540A1 (en) * | 1982-11-03 | 1984-06-14 | GeWerTec Gesellschaft für Werkstofftechnik mbH, 4600 Dortmund | Method and apparatus for high-temperature soldering and brazing |
JPS6437077A (en) * | 1987-08-03 | 1989-02-07 | Hitachi Ltd | Reflow soldering |
JPH067926A (en) * | 1992-06-10 | 1994-01-18 | Showa Alum Corp | Method for joining aluminum material |
JP2843814B2 (en) * | 1994-12-14 | 1999-01-06 | 株式会社アルテクス | Ultrasonic soldering method |
JP3347512B2 (en) | 1995-03-17 | 2002-11-20 | 富士通株式会社 | Solder alloy for low-temperature bonding, electronic device using the same, and method of manufacturing the same |
JP3963501B2 (en) * | 1996-06-12 | 2007-08-22 | 内橋エステック株式会社 | Electronic component mounting method |
JPH10216630A (en) * | 1997-01-31 | 1998-08-18 | Shibaura Eng Works Co Ltd | Soldering method for ultrasonic vibrator and ultrasonic vibration device |
JP3592486B2 (en) * | 1997-06-18 | 2004-11-24 | 株式会社東芝 | Soldering equipment |
JP2001230272A (en) * | 2000-02-21 | 2001-08-24 | Nippon Avionics Co Ltd | Flip chip having lead-free solder multilayer bump and lead-free flip chip assembly |
-
1999
- 1999-06-11 JP JP16516599A patent/JP3580731B2/en not_active Expired - Fee Related
-
2000
- 2000-06-07 DE DE60016413T patent/DE60016413T2/en not_active Expired - Lifetime
- 2000-06-07 WO PCT/JP2000/003678 patent/WO2000076708A1/en active IP Right Grant
- 2000-06-07 US US10/009,168 patent/US6702175B1/en not_active Expired - Fee Related
- 2000-06-07 EP EP00935564A patent/EP1195217B1/en not_active Expired - Lifetime
-
2004
- 2004-01-20 US US10/759,191 patent/US20040144829A1/en not_active Abandoned
Patent Citations (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4885841A (en) * | 1989-02-21 | 1989-12-12 | Micron Technology, Inc. | Vibrational method of aligning the leads of surface-mount electronic components with the mounting pads of printed circuit boards during the molten solder mounting process |
US5094700A (en) * | 1990-03-22 | 1992-03-10 | University Of Cincinnati | Solder and brazing alloys having improved properties and method of preparation |
US5256370A (en) * | 1992-05-04 | 1993-10-26 | The Indium Corporation Of America | Lead-free alloy containing tin, silver and indium |
US5256370B1 (en) * | 1992-05-04 | 1996-09-03 | Indium Corp America | Lead-free alloy containing tin silver and indium |
US5511719A (en) * | 1993-06-01 | 1996-04-30 | Nippondenso Co., Ltd. | Process of joining metal members |
US5492263A (en) * | 1994-05-26 | 1996-02-20 | Delco Electronics Corp. | Method for wire bonding an aluminum wire to a lead of an electronics package |
US5918795A (en) * | 1996-02-09 | 1999-07-06 | Matshushita Electric Industrial Co., Ltd. | Soldering alloy, cream solder and soldering method |
US5730932A (en) * | 1996-03-06 | 1998-03-24 | International Business Machines Corporation | Lead-free, tin-based multi-component solder alloys |
US6457632B1 (en) * | 1997-04-25 | 2002-10-01 | Kabushiki Kaisha Toshiba | Solder alloy and bonding method of substrate and electric or electronic parts with solder alloy |
US6651870B2 (en) * | 1997-04-25 | 2003-11-25 | Kabushiki Kaisha Toshiba | Solder alloy, substrate with solder alloy for mounting electronic part, member to be bonded of electronic part, and electronic-part-mounted substrate |
US6047876A (en) * | 1997-09-12 | 2000-04-11 | Materials Resources International | Process of using an active solder alloy |
US6271601B1 (en) * | 1998-05-12 | 2001-08-07 | Hitachi, Ltd. | Wire bonding method and apparatus and semiconductor device |
US6171415B1 (en) * | 1998-09-03 | 2001-01-09 | Uit, Llc | Ultrasonic impact methods for treatment of welded structures |
US6319461B1 (en) * | 1999-06-11 | 2001-11-20 | Nippon Sheet Glass Co., Ltd. | Lead-free solder alloy |
US6702175B1 (en) * | 1999-06-11 | 2004-03-09 | Matsushita Electric Industrial Co., Ltd. | Method of soldering using lead-free solder and bonded article prepared through soldering by the method |
US20020031903A1 (en) * | 2000-08-29 | 2002-03-14 | Hiroshi Yamauchi | Component mounting apparatus and method, component mounting system having the apparatus, and circuit board manufactured by the method |
US20020056741A1 (en) * | 2000-11-16 | 2002-05-16 | Shieh Wen Lo | Application of wire bonding technology on wafer bump, wafer level chip scale package structure and the method of manufacturing the same |
Also Published As
Publication number | Publication date |
---|---|
JP3580731B2 (en) | 2004-10-27 |
DE60016413D1 (en) | 2005-01-05 |
WO2000076708A1 (en) | 2000-12-21 |
EP1195217A1 (en) | 2002-04-10 |
JP2000351065A (en) | 2000-12-19 |
EP1195217B1 (en) | 2004-12-01 |
EP1195217A4 (en) | 2003-07-23 |
US6702175B1 (en) | 2004-03-09 |
DE60016413T2 (en) | 2005-11-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5389160A (en) | Tin bismuth solder paste, and method using paste to form connection having improved high temperature properties | |
US5229070A (en) | Low temperature-wetting tin-base solder paste | |
EP0855242B1 (en) | Lead-free solder | |
US5452842A (en) | Tin-zinc solder connection to a printed circuit board or the like | |
JP4438974B2 (en) | Solder paste | |
EP1614500A1 (en) | Solder paste and printed board | |
US20030156969A1 (en) | Lead-free tin-silver-copper alloy solder composition | |
WO1997000753A1 (en) | Solder, and soldered electronic component and electronic circuit board | |
US6702175B1 (en) | Method of soldering using lead-free solder and bonded article prepared through soldering by the method | |
JP2004298931A (en) | High-temperature lead-free solder alloy and electronic part | |
US6474537B1 (en) | Soldering method using a Cu-containing lead-free alloy | |
JP4392020B2 (en) | Lead-free solder balls | |
JP3299091B2 (en) | Lead-free solder alloy | |
MX2007009927A (en) | Method and arrangement for thermally relieved packages with different substrates. | |
JP3878978B2 (en) | Lead-free solder and lead-free fittings | |
JP2004034134A (en) | Line-solder and process of producing electronic equipment | |
JP3963501B2 (en) | Electronic component mounting method | |
JPH1052791A (en) | Lead free solder alloy | |
JP2003266193A (en) | Lead-free solder for feeding into solder bath | |
JP2004320046A (en) | Method of soldering lead-free solder, and junction by using same method of soldering | |
JP4151409B2 (en) | Soldering method | |
JPH0332487A (en) | Soldering material | |
JP2004031724A (en) | Soldering method for work and soldering mounter | |
JP3580730B2 (en) | Flow soldering apparatus and soldering method for lead-free solder, and joined body | |
JP2005111526A (en) | Soldering method of lead-free solder and member bonded by soldering |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |