WO1984002867A1 - Method of laser soldering - Google Patents
Method of laser soldering Download PDFInfo
- Publication number
- WO1984002867A1 WO1984002867A1 PCT/US1983/000112 US8300112W WO8402867A1 WO 1984002867 A1 WO1984002867 A1 WO 1984002867A1 US 8300112 W US8300112 W US 8300112W WO 8402867 A1 WO8402867 A1 WO 8402867A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pad
- solder
- strand
- soldering
- inch
- Prior art date
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Classifications
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- 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
- H05K3/341—Surface mounted components
- H05K3/3421—Leaded components
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- 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
- B23K1/005—Soldering by means of radiant energy
- B23K1/0056—Soldering by means of radiant energy soldering by means of beams, e.g. lasers, E.B.
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/02—Bonding areas; Manufacturing methods related thereto
- H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
- H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
- H01L2224/0554—External layer
- H01L2224/05599—Material
- H01L2224/056—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/4501—Shape
- H01L2224/45012—Cross-sectional shape
- H01L2224/45014—Ribbon connectors, e.g. rectangular cross-section
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/4805—Shape
- H01L2224/4809—Loop shape
- H01L2224/48091—Arched
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/484—Connecting portions
- H01L2224/4847—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
- H01L2224/48472—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
- H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
- H01L2224/852—Applying energy for connecting
- H01L2224/8521—Applying energy for connecting with energy being in the form of electromagnetic radiation
- H01L2224/85214—Applying energy for connecting with energy being in the form of electromagnetic radiation using a laser
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01013—Aluminum [Al]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/30—Technical effects
- H01L2924/301—Electrical effects
- H01L2924/3025—Electromagnetic shielding
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- 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
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
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- 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
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/09—Use of materials for the conductive, e.g. metallic pattern
- H05K1/092—Dispersed materials, e.g. conductive pastes or inks
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- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/01—Dielectrics
- H05K2201/0104—Properties and characteristics in general
- H05K2201/0112—Absorbing light, e.g. dielectric layer with carbon filler for laser processing
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- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
- H05K2201/10007—Types of components
- H05K2201/10189—Non-printed connector
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- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
- H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
- H05K2201/10742—Details of leads
- H05K2201/1075—Shape details
- H05K2201/10757—Bent leads
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- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
- H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
- H05K2201/10954—Other details of electrical connections
- H05K2201/10984—Component carrying a connection agent, e.g. solder, adhesive
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- 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
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/10—Using electric, magnetic and electromagnetic fields; Using laser light
- H05K2203/107—Using laser light
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- 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
- H05K3/3494—Heating methods for reflowing of solder
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the laser beam so controlled to a microsized diameter, would not melt a sufficient amount of the solder pad to effect a reflowed fillet along the entire bottom surface of a large, flat electrical lead wire, resulting in a weak joint. Reflowing solder about a small, round wire is considerably easier due to surface tension about a round surface. If the interfacing diameter of the laser beam were to be modified or expanded, the beam energy/unit surface area would not be sufficient to melt the solder and effect the reflowed joint.
- the solderable joints are supported on ceramic substrates used to conduct heat away during normal vehicle operation of the module, thereby preventing destruction of the printed circuit and soldered joints due to momentary high currents.
- ceramic substrates act as a heat sink and facilitate rapid run-off of heat during soldering which inhibits proper thermal control of the laser diameter, and certainly makes it impossible to use low powered laser beams if proper soldering is to be effected.
- Increasing the laser beam power by itself is not an answer to this dilemma because a high powered beam, focused at a desired diameter, will heat the solder excessively, leaving little room for processing error and resulting in damage to adjacent sensitive electronic parts.
- the invention is a method of soldering one or more electrical lead strands to a printed electrical path.
- the method comprises the steps of: (a) planting the path on a ceramic substrate and attaching at least one solder pad to a portion of the printed electrical path; (b) forcing a surface portion of the electrical lead strand into full interengagement with the pad with an engaging force sufficient to permit heat conduction therebetween for soldering, the pad having a width greater than the width of the surface portion of the electrical lead strand, and the interengaging surface portion of the electrical lead strand having a width greater than .03 inch, the portion of the electrical lead strand and pad constituting a soldering assembly; and (c) directing a defocused laser beam onto the soldering assembly, the beam having a beam power of at least 100 watts, a beam spot diameter no less than the width of the electrical lead strand and no greater than the width of the pad, and a beam on-time effective to exert a controlled thermal radius on the soldering assembly to
- the electrical lead strand have a flat interengaging surface and the pad have a mating, generally flat interengaging surface (allowing for a slight radius due to surface tension). It is advantageous if the laser beam is defocused by an amount of 4 inch (with a five inch focal length lens) and have a focal point located above the soldering assembly to thereby protect against reflection of the laser beam to other sensitive electronic components. It is also desirable that the center of mass of the interengaging surface of the electrical lead strand be aligned with the center of the pad against which it is forced.
- the thermal radius is increased by at least one of the following: (a) a coating of energy absorbing paint, or (b) by increasing the temperature of the soldering assembly by preheating to a temperature of at least 100°C. It is further advantageous if the laser beam spot diameter is controlled within the dimensional limits of .03-.09 inch and that the beam on-time be limited to 50-2000 milliseconds (0.05-2.0 aecurius).
- the beam parameters Can be optimized by use of the following mathematical relationship:
- c is the critical thermal radius (melt radius) a is the Gaussian radius at l/e 2 point 1n is logarithm T m is the melting temperature of the solder minus the specimen preheat temperature P is the laser beam power in watts A is the surface absorptivity of the solder at 10.6 microns R is the thermal resistance per unit area of the system t c is the critical time to bring the solder to the T m temperature (beam on-time is approximately t c /0.975) C is the heat capacity of the system. It is advantageous if a shielding gas is used during soldering to prevent the flux from burning for easy removal of the flux after soldering.
- the ceramic, supporting the electrical path be selected as one or both from the group consisting of alumina and beryllia, and advantageously have a film thickness of at least .02 inch.
- the electrical lead strands extend from an annular integral lead frame which is encapsulated within an annular nonconductive housing.
- the leads may be preferably comprised of a tin coated brass material, the pad comprised of a tin/lead/silver or tin/lead alloy, and the printed circuit be comprised of palladium/silver material.
- a flux is typically employed between the pad and strand and is preferably comprised of nonactivated rosin. It is also preferable that the laser beam be a CO 2 generated laser.
- Figure 1 is a photograph illustrating a microelectronic device having several joints soldered by the method of this invention.
- Figure 2 is an enlarged photograph illustrating some of the electrical leads of Figure 1 successfully soldered in accordance with the present invention.
- Figure 3 is a schematic sectional elevational view of a portion of the device of Figure 1 showing one soldered joint and an insert ( Figure 3a) illustrating a plan view of the soldering joint.
- Figure 4 is a graphical illustration depicting the variation of beam on-time with beam power at various combinations (the cross hatched portion showing the acceptable manufacturing combinations that are useful).
- Figure 5 is a heat flow diagram between the various materials forming the soldering assembly of Figure 2.
- Figure 6 is a schematic diagram illustrating a Gaussian energy beam distribution across the solder pad.
- Figure 7 is a graphical illustration of critical thermal radius varying as a function of beam on-time at various power levels.
- Figure 8 is a graphical illustration of beam power as a function of soldering assembly temperature at various preheat temperatures T o
- the invention is applied to the soldering of integral electrical leads to a thick film ignition module useful in controlling the starting of an internal combustion engine.
- the device to be soldered is more particularly shown in Figures 1 and 3, and more completely disclosed in copending U.S. application Serial
- Thick Flow Substrate invented by D. Davis and C. Henritzy, assigned to the assignee of this invention..
- the microelectronic device 10 comprises an annular lead frame 11 which is encapsulated or buried within a plastic annular housing 12 with integral lead strands 13 projecting inwardly through the sides of the housing and depending downwardly therefrom.
- This device here has nine electrial lead strands projecting inwardly that need to be soldered to a printed electrical circuit 14 supported on a ceramic substrate 15 and recessed below the top opening of the housing.
- One of the substrate materials is alumina and occupies 75% of the total substrate; the other is beryllia.
- the ceramics are glued to a supporting aluminum plate 16 which acts as a heat sink.
- Each of the electrical lead strands is comprised of a brass conductive strip nominally comprised of 70% copper and 30% zinc.
- the projecting portion of the lead strand is given an inverted U-shape 17 with the terminal portion defining a foot 18 to be soldered to a portion 14a of the printed circuit 14.
- the foot of the electrical strand has a flat cross sectional configuration here sized to be .04 inch wide and .009 inch thick. Numerous adjacent sensitive electronic components are present such as resistors 19, capacitors 20, and electronic chip 21.
- a ceramic substrate is required in this device because of the necessity for maintainig a heat sink during operation of the ignition module for engine starting. Ceramic has a higher conductivity than a plastic (epoxy fiberglass-impregnated) substrate, typically used by the prior art.
- the alumina is nominally comprised of 94%.
- AI 2 O 3 and used in a thickness about .02 inch (.56 millimeters);
- the beryllia substrate is nominally comprised of 99.5% minimum BeO and in a thickness of about .02 inch.
- the aluminum supporting plate 16 is comprised of AA3003H14 aluminum alloy and used in a thickness of about .06 inch.
- the electrical lead strands are of a size much greater than that normally employed by the prior art, having a width 22 greater than .03 inch, and have a flat, rectangular cross section (i.e., .04 inch x .009 inch). Such electrical lead strands require different processing technology to ensure that a completely solid solder joint takes place throughout the entire interface (under-surface) of the electrical lead foot as well as around the edges thereof.
- the method herein comprises essentially three Steps: 1.
- a printed electrical circuit path 14 is planted on a ceramic substrate 15 and at least one solder pad 24 is attached to a portion 14a of the printed electrical path.
- the solder pad may be deposited by conventional techniques which normally include silk screening.
- the pad here is a soldering composition comprised of 10% tin, 88% lead, and 2% silver.
- the pad is formed to have a generally flat interfacing surface 25 (except for curvature due to surface tension) with a width greater than the width of the electrical lead.
- each of the pads have a rectangular configuration of .08 inch wide, .1 inch long, and .006 inch high.
- the surface portion 23 of the electrical lead is forced into full interengagement with the soldering pad (against surface 25) with an engaging force of 50-150 grams. It is important that the pad 24 have a width 26 greater than the width 72 of the electrical strand and the interengaging surface portion of the electrical lead have a width 22 greater than .03 inch.
- the electrical lead strand is bent with a radius or U-shape as shown in Figures 2. and 3; this allows the strand to impart a spring bias against the top surface 25 of the pad.
- the end of the pad has a curved foot 18 portion to permit mating of the interengaging flat surfaces 23-25.
- a defocused laser beam is directed onto the soldering assembly, the beam having a beam power of at least 100 watts, a beam spot diameter 27 which is no less than the width 22 of the electrical strand and no greater than the pad width 26, as well as a beam on-time effective to exert a controlled thermal radius on the soldering assembly to reflow only a preselected portion of the soldering pad and effect a soldered joint between the pad and the electrical strand portion, the joint having a strength of at least 400 grams.
- the laser beam 28 employed here was generated by a 370 watt CO 2 laser apparatus and was focused at a point 29 a distance 30 (.4 inch) above the soldering assembly. The beam impinged downwardly on the foot 18 and solder pad 24 assembly.
- the central axis of the laser beam was aligned with the center of mass 31 of the electrical lead at its engaging portion and also aligned with the center 32 of the soldering pad.
- a small amount of soldering flux was applied to the area between the soldering surfaces prior to soldering, such flux being typically nonactivated rosin microflux.
- the soldering assembly was preheated to 150°C to lower the power requirement and to eliminate the possibility of thermal shock.
- a coaxial nitrogen gas stream was used to (a) shield the solder area from oxidation and thereby protect the soldering joint from a black coating deposition, and (b) to protect the focusing lens from Demg roggea oy smoke.
- the beam itself, as it emanated from the generating device, had a diameter of about .6 inch, and was defocused slightly above the soldering assembly to have a spot diameter on the soldering assembly of .030-.080 inch. The best results were obtained when the spot diameter was 0.050-0.060 inch.
- Room temperature specimens which were not preheated required a longer beam on-time or a higher power level than preheated specimens.
- a room temperature specimen required 50-75% more power than a specimen preheated to 150°C for the same beam on-time.
- a preheat temperature of the soldering assembly be employed which is at least 100°C.
- the power may be reduced by 25% compared to the room temperature (20oC) specimen (see Figure 8 ) .
- the energy requirement or power level of the laser beam can be decreased by increasing the surface absorptivity of the soldering lead.
- the power level can be reduced, for example, from 400 watts to 200 watts, by applying a black coating on the lead foot or by eliminating the nitrogen gas shielding.
- the effect of the beam spot on beam on-time is such that the minimum time for satisfactory fillet formation is progressively decreased as the beam spot diameter is increased.
- the widest time range for satisfactory joints was obtained when the beam spot diameter was about .05 inch (1.27 millimeters).
- An excessively large spot diameter (such as .085 inch) coupled with a long beam on-time (such as .3 seconds) sometimes caused a beam reflection problem; such reflection causes heat damage to the adjacent components such as resistors or capacitors.
- the reflection problem can be reduced by use of a proper defocused beam (proper spot diameter) with the focal point above the soldering assembly.
- the shielding gas flow increases the power requirement; but without a shielding gas, a black residue is left by the burned flux. Since the black residue cannot be removed easily, it is recommended that the shielding gas be employed. A gentle blow of the nitrogen gas is adequate to prevent the flux from burning or charring.
- the beam spot diameter has been used as a common measure in laser thermal processing to define the beam size on the work piece.
- this diameter by itself cannot be used in predicting the amount of thermal work accomplished.
- the critical thermal radius of this invention is the radius of an area on the work piece within which the desired thermal effect is achieved. It represents the radius of the melt area in laser soldering.
- the penetration depth of the light field in a good conductor lies in the range of 10 -6 centimeters or 10-100 atomic layers.
- laser absorption is considered to occur at the surface in cases of laser soldering.
- the heat flow system can be proportioned with heat flow into two components: accummulated heat and conducted heat.
- the heat input q is partially accummulated in the solder pad (q s ) and the alumina (q A ), and th e rest of the heat is conducted away to the heat sink q 3 (aluminum plate).
- T 2 is the average temperature of the alumina substrate through the thickness and, if one assumes a parabolic temperature profile within the alumina substrate, the average temperature of the substrate T 2 is given by the relationship T 2 is equal to T 1 /3.
- the energy balance of the heat flow system in Figure 6 yields a first order differential equation:
- the radius of a Gaussian beam is typically defined as the radius at which the intensity falls to 1/e 2 of its peaked value (86.5% of the total beam energy is contained within the area of this radius).
- the intensity profile of a Gaussian beam is illustrated in Figure 6.
- This radius c is selected as the critical thermal radius because it defines the area where the desired thermal effect is achieved.
- c is the critical thermal radius a is the Gaussian radius at 1/e 2 point 1n is logarithm T m is the melting temperature of the solder minus the specimen temperature P is the laser beam power
- A is the surface absorptivity of the solder at 10.6 microns
- R is thermal resistance per unit area of the system
- t c is the critical time to bring solder to T m
- C is the heat capacity of the system.
- Figure 7 shows the theoretical c radius as a function of beam on-time when the beam spot diameter is
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Laser Beam Processing (AREA)
- Manufacturing Of Electrical Connectors (AREA)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1983/000112 WO1984002867A1 (en) | 1983-01-24 | 1983-01-24 | Method of laser soldering |
DE19833390451 DE3390451C2 (de) | 1983-01-24 | 1983-01-24 | Verfahren zum Laser-L¦ten |
GB08423754A GB2143759B (en) | 1983-01-24 | 1983-01-24 | Method of laser soldering |
JP58500980A JPS60500204A (ja) | 1983-01-24 | 1983-01-24 | レ−ザはんだ付け法 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1983/000112 WO1984002867A1 (en) | 1983-01-24 | 1983-01-24 | Method of laser soldering |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1984002867A1 true WO1984002867A1 (en) | 1984-08-02 |
Family
ID=22174819
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1983/000112 WO1984002867A1 (en) | 1983-01-24 | 1983-01-24 | Method of laser soldering |
Country Status (4)
Country | Link |
---|---|
JP (1) | JPS60500204A (de) |
DE (1) | DE3390451C2 (de) |
GB (1) | GB2143759B (de) |
WO (1) | WO1984002867A1 (de) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0218069A1 (de) * | 1985-09-19 | 1987-04-15 | Siemens Aktiengesellschaft | Verfahren zum Verschweissen mittels Laserlicht |
EP0515113A1 (de) * | 1991-05-20 | 1992-11-25 | General Electric Company | Verfahren und Gerät zur örtlichen Lötung an einer keramischen Unterlage |
WO1999063795A1 (de) * | 1998-06-02 | 1999-12-09 | Siemens S. A. | Verfahren zur herstellung von verdrahtungen mit lothöckern |
WO2022229078A1 (de) * | 2021-04-30 | 2022-11-03 | Vitesco Technologies Germany Gmbh | Leiterplatte, kraftfahrzeug und verfahren zur herstellung einer elektrisch leitenden verbindung eines drahts mit einer leiterplatte |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2534590B2 (ja) * | 1991-04-11 | 1996-09-18 | ティーディーケイ株式会社 | レ―ザ光による電子部品のはんだ付け方法 |
JP4522752B2 (ja) * | 2004-06-10 | 2010-08-11 | 三菱電機株式会社 | 半田付けによる端子接合方法 |
JP2012216789A (ja) * | 2011-03-30 | 2012-11-08 | Fujifilm Corp | 基板搬送用キャリア |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3294951A (en) * | 1963-04-30 | 1966-12-27 | United Aircraft Corp | Micro-soldering |
US3402460A (en) * | 1965-05-26 | 1968-09-24 | Westinghouse Electric Corp | Attachment of leads to semiconductors |
US3520055A (en) * | 1967-04-26 | 1970-07-14 | Western Electric Co | Method for holding workpieces for radiant energy bonding |
US3597579A (en) * | 1970-06-25 | 1971-08-03 | Western Electric Co | Method of trimming capacitors |
US3614832A (en) * | 1966-03-09 | 1971-10-26 | Ibm | Decal connectors and methods of forming decal connections to solid state devices |
US3889272A (en) * | 1974-05-30 | 1975-06-10 | Bell Telephone Labor Inc | Metal film recording media for laser writing |
US4179310A (en) * | 1978-07-03 | 1979-12-18 | National Semiconductor Corporation | Laser trim protection process |
US4320281A (en) * | 1980-07-31 | 1982-03-16 | Western Electric Company, Inc. | Laser bonding technique and article formed thereby |
US4341942A (en) * | 1978-10-31 | 1982-07-27 | International Business Machines Corporation | Method of bonding wires to passivated chip microcircuit conductors |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5539434B2 (de) * | 1972-08-25 | 1980-10-11 | ||
DE2735231A1 (de) * | 1977-08-04 | 1979-02-15 | Siemens Ag | Verfahren und vorrichtung zur herstellung von loetverbindungen mittels energiestrahlung |
JPS5562680A (en) * | 1978-10-31 | 1980-05-12 | Ibm | Wire bonding method |
US4230930A (en) * | 1979-01-25 | 1980-10-28 | Ford Motor Company | Laser welding method for electrical wire connection to a terminal pin of an exhaust gas sensor |
JPS57111089A (en) * | 1980-12-27 | 1982-07-10 | Omron Tateisi Electronics Co | Method of sodering chip part |
-
1983
- 1983-01-24 DE DE19833390451 patent/DE3390451C2/de not_active Expired
- 1983-01-24 GB GB08423754A patent/GB2143759B/en not_active Expired
- 1983-01-24 JP JP58500980A patent/JPS60500204A/ja active Granted
- 1983-01-24 WO PCT/US1983/000112 patent/WO1984002867A1/en active Application Filing
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3294951A (en) * | 1963-04-30 | 1966-12-27 | United Aircraft Corp | Micro-soldering |
US3402460A (en) * | 1965-05-26 | 1968-09-24 | Westinghouse Electric Corp | Attachment of leads to semiconductors |
US3614832A (en) * | 1966-03-09 | 1971-10-26 | Ibm | Decal connectors and methods of forming decal connections to solid state devices |
US3520055A (en) * | 1967-04-26 | 1970-07-14 | Western Electric Co | Method for holding workpieces for radiant energy bonding |
US3597579A (en) * | 1970-06-25 | 1971-08-03 | Western Electric Co | Method of trimming capacitors |
US3889272A (en) * | 1974-05-30 | 1975-06-10 | Bell Telephone Labor Inc | Metal film recording media for laser writing |
US4179310A (en) * | 1978-07-03 | 1979-12-18 | National Semiconductor Corporation | Laser trim protection process |
US4341942A (en) * | 1978-10-31 | 1982-07-27 | International Business Machines Corporation | Method of bonding wires to passivated chip microcircuit conductors |
US4320281A (en) * | 1980-07-31 | 1982-03-16 | Western Electric Company, Inc. | Laser bonding technique and article formed thereby |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0218069A1 (de) * | 1985-09-19 | 1987-04-15 | Siemens Aktiengesellschaft | Verfahren zum Verschweissen mittels Laserlicht |
EP0515113A1 (de) * | 1991-05-20 | 1992-11-25 | General Electric Company | Verfahren und Gerät zur örtlichen Lötung an einer keramischen Unterlage |
WO1999063795A1 (de) * | 1998-06-02 | 1999-12-09 | Siemens S. A. | Verfahren zur herstellung von verdrahtungen mit lothöckern |
WO2022229078A1 (de) * | 2021-04-30 | 2022-11-03 | Vitesco Technologies Germany Gmbh | Leiterplatte, kraftfahrzeug und verfahren zur herstellung einer elektrisch leitenden verbindung eines drahts mit einer leiterplatte |
Also Published As
Publication number | Publication date |
---|---|
GB2143759A (en) | 1985-02-20 |
GB2143759B (en) | 1986-12-10 |
DE3390451C2 (de) | 1989-05-11 |
JPS60500204A (ja) | 1985-02-21 |
JPH0243578B2 (de) | 1990-09-28 |
DE3390451T1 (de) | 1986-02-20 |
GB8423754D0 (en) | 1984-10-24 |
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