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GB2103980A - Soldering components to a substrate - Google Patents

Soldering components to a substrate Download PDF

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Publication number
GB2103980A
GB2103980A GB08125129A GB8125129A GB2103980A GB 2103980 A GB2103980 A GB 2103980A GB 08125129 A GB08125129 A GB 08125129A GB 8125129 A GB8125129 A GB 8125129A GB 2103980 A GB2103980 A GB 2103980A
Authority
GB
United Kingdom
Prior art keywords
solder
substrate
composition
component
bond
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.)
Granted
Application number
GB08125129A
Other versions
GB2103980B (en
Inventor
Patrick Wiliam Henry Moore
Graham George Lewis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB08125129A priority Critical patent/GB2103980B/en
Publication of GB2103980A publication Critical patent/GB2103980A/en
Application granted granted Critical
Publication of GB2103980B publication Critical patent/GB2103980B/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0222Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
    • B23K35/0244Powders, particles or spheres; Preforms made therefrom
    • B23K35/025Pastes, creams, slurries
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/30Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/3457Solder materials or compositions; Methods of application thereof
    • H05K3/3485Applying solder paste, slurry or powder
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203Fillers and particles
    • H05K2201/0206Materials
    • H05K2201/0209Inorganic, non-metallic particles
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203Fillers and particles
    • H05K2201/0206Materials
    • H05K2201/0215Metallic fillers
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10613Details of electrical connections of non-printed components, e.g. special leads
    • H05K2201/10621Components characterised by their electrical contacts
    • H05K2201/10636Leadless chip, e.g. chip capacitor or resistor
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/30Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/341Surface mounted components
    • H05K3/3431Leadless components
    • H05K3/3442Leadless components having edge contacts, e.g. leadless chip capacitors, chip carriers
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

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

A solder paste composition includes a particulate solder alloy, a flux, and a solid particulate material, e.g. copper, having a melting point higher than that of the solder alloy. Components (11) soldered to a substrate with the solder paste composition are spaced from the substrate by the solid particles (21) therebetween. This facilitates removal of flux residues from the space between the component and the substrate. <IMAGE>

Description

SPECIFICATION Soldering components This invention relates to the fabrication of circuits wherein components are soldered to a substrate.
There are a variety of electronic circuit constructions, for example film circuits, wherein individual components are soldered to a substrate.
The solder bonds provide the dual purpose of attaching the components to the substrate and of providing eiectrical connection to conductors disposed in the substrate. To effect soldering the interfaces between the substrate and the various components are treated with a paste comprising a particulate solder alloy and a flux. The assembly is heated to fuse the solder and effect the solder bond.
It will be appreciated that, as in any soldering process, there will be flux residues which, if not removed, will cause corrosion over an extended period. This produces degradation of the soldered joint with a consequent adverse effect on the electrical function of the circuit. Removal of these flux residues is difficult as, owing to the very small clearance between the individual components and the substrate on which they are mounted, they become trapped in a region where the effects of corrosion damage are most deleterious.
The object of the invention is to minimise or to overcome this disadvantage.
According to one aspect of the invention there is provided a solder composition comprising a particulate solder alloy, a flux, and a particulate material of higher melting point than the solder, said material being such that it does not reduce the integrity of a solder bond formed by fusion of the solder composition.
According to another aspect of the invention there is provided a method of soldering a component to a substrate, said method including forming a solder bond between the component and the substrate, and incorporating into said bond a solid particulate material whereby the component is spaced from the substrate, and wherein said material is of higher melting point than the solder and is such that is does not reduce the integrity of the solder bond.
An embodiment of the invention will now be described with reference to the accompanying drawings in which Figs. 1 and 2 are cross sec.ions of a component and substrate assembly respectively before and after formation of a solder bond therebetween.
Referring to Fig. 1, a component 1 1 having terminal contacts 12 is mounted on a substrate 1 3 provided with conductor tracks 14, e.g. of copper. A quantity of a solder paste 1 5 is disposed between each terminal contact 12 and the corresponding track 1 4. The solder paste comprises a particulate solder alloy. a flux which also provides the liquid vehicle of the composition, and a solid particulate material having a melting point higher than that of the working temperature of the solder. Typically the paste is applied to the substrate by a screen printing process and the component is placed in position on top of the paste.
Preferably the solid particulate material is in the form of spheres of a substantially uniform diameter. Typically we employ copper spheres having a diameter of 20 to 200 microns, but other conductive or non-conductive materials may be used, for example steel, glass or silica. The material may be in the form of spheres, powder, or short lengths of wire or fibre. It is of course necessary that the material does not interact to any deleterious extent with the solder.
It will be appreciated that if spherical particles are used this will facilitate movement of the components in any necessary adjustment to a fixed exact position on the substrate. In situations where such movement is not necessary then it is immaterial whether the particles are spherical or irregular. It is of course preferable that the particles should be of such a size that the paste can be applied by a screen printing process.
Solder bonding is effected by heating the assembly to fuse the solder. During this process the surface tension of the molten solder draws the component towards the bond and into abutment with the solid particles 21 (Fig. 2) which thus space the component a precisely defined distance from the substrate. We have also found that, where substantially spherical solid particles are used, the surface tension of the molten solder between the terminal contacts 1 2 and the respective conductor track 1 4 tends to orientate the component such that the contacts 12 and tracks 14 are brought into register thus correcting any slight misalignment of the component 11.
After the solder has cooled and solidified the assembly may be washed to remove flux residues.
As the component 11 is spaced from the substrate 13 by the particles 21 the risk of entrapment of flux residues between the component and the substrate is minimised.
The techniques described herein may be used in a variety of applications. Thus they may be employed not only in thin film and thick film circuit applications but also in the production of conventional printed circuits. The solder alloy will typically comprise a tin/lead alloy, but for certain specialised applications other solder alloys may of course be employed.

Claims (10)

1. A solder composition comprising a particulate solder alloy, a flux. and a particulate material of higher melting point that the solder.
said material being such that it does not reduce the integrity of a solder bond formed by fusion of the solder composition.
2. A composition as claimed in claim 1, whereto the particulate material comprises substantially spherical particles.
3. A composition as claimed in claim 2 wherein said spheres have a diameter of 20 to 200 microns.
4. A composition as claimed in claim 1. 2 or 3.
wherein the particulate material is copper, glass, silica, steel or mixtures thereof.
5. A composition as claimed in any one of claims 1 to 4, wherein said solder alloy is a tin/lead alloy.
6. A solder composition substantially as described herein with reference to the accompanying drawings.
7. A method of soldering a component to a substrate, said method including forming a solder bond between the component and the substrate, and incorporating into said bond a solid particulate material whereby the component is spaced from the substrate, and wherein said material is of higher melting point than the solder and is such that it does not reduce the integrity of the solder bond.
8. A method as claimed in claim 7, wherein said solder bond is devised from a solder paste applied by a screen printing process.
9. A method of soldering substantially as described herein with reference to the accompanying drawings.
10. A circuit arrangement incorporating components soldered by a method as claimed in claim 7, 8 or 9.
GB08125129A 1981-08-18 1981-08-18 Soldering components to a substrate Expired GB2103980B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08125129A GB2103980B (en) 1981-08-18 1981-08-18 Soldering components to a substrate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08125129A GB2103980B (en) 1981-08-18 1981-08-18 Soldering components to a substrate

Publications (2)

Publication Number Publication Date
GB2103980A true GB2103980A (en) 1983-03-02
GB2103980B GB2103980B (en) 1986-01-22

Family

ID=10524003

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08125129A Expired GB2103980B (en) 1981-08-18 1981-08-18 Soldering components to a substrate

Country Status (1)

Country Link
GB (1) GB2103980B (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0164906A1 (en) * 1984-05-14 1985-12-18 RAYCHEM CORPORATION (a Delaware corporation) Solder composition
EP0259635A1 (en) * 1986-09-05 1988-03-16 Forschungszentrum Jülich Gmbh Method for the production of thermally highly stressed cooling elements
EP0612577A1 (en) * 1993-02-22 1994-08-31 AT&T Corp. Article comprising solder with improved mechical properties, and method of making the solder
WO1997035683A1 (en) * 1996-03-22 1997-10-02 Emitec Gesellschaft Für Emissionstechnologie Mbh Soldered metal honeycomb structures with spacers in the solder gaps and process and solder for its production
WO2004065050A3 (en) * 2003-01-14 2004-09-30 Molex Inc Method and system for solder connecting electrical devices
WO2004107832A1 (en) * 2003-05-22 2004-12-09 Rf Micro Devices, Inc. Solder filler
EP1009202A4 (en) * 1997-06-04 2005-08-17 Ibiden Co Ltd SOLDERING ELEMENT FOR PRINTED PCB
EP1496733A3 (en) * 2003-07-10 2007-03-28 Delphi Technologies, Inc. Electronic package having controlled height stand-off solder joint
GB2603488A (en) * 2021-02-04 2022-08-10 Rockwood Composites A soldering compound

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0164906A1 (en) * 1984-05-14 1985-12-18 RAYCHEM CORPORATION (a Delaware corporation) Solder composition
EP0259635A1 (en) * 1986-09-05 1988-03-16 Forschungszentrum Jülich Gmbh Method for the production of thermally highly stressed cooling elements
EP0612577A1 (en) * 1993-02-22 1994-08-31 AT&T Corp. Article comprising solder with improved mechical properties, and method of making the solder
WO1997035683A1 (en) * 1996-03-22 1997-10-02 Emitec Gesellschaft Für Emissionstechnologie Mbh Soldered metal honeycomb structures with spacers in the solder gaps and process and solder for its production
JP2000507160A (en) * 1996-03-22 2000-06-13 エミテツク ゲゼルシヤフト フユア エミツシオンステクノロギー ミツト ベシユレンクテル ハフツング Brazed metal honeycomb body with spacers in brazing gap, brazing method and brazing method for use
CN1081967C (en) * 1996-03-22 2002-04-03 发射技术有限公司 Soldered metal honeycomb structures with spacers in solder gaps and process and solder for its prodn.
EP1009202A4 (en) * 1997-06-04 2005-08-17 Ibiden Co Ltd SOLDERING ELEMENT FOR PRINTED PCB
WO2004065050A3 (en) * 2003-01-14 2004-09-30 Molex Inc Method and system for solder connecting electrical devices
WO2004107832A1 (en) * 2003-05-22 2004-12-09 Rf Micro Devices, Inc. Solder filler
EP1496733A3 (en) * 2003-07-10 2007-03-28 Delphi Technologies, Inc. Electronic package having controlled height stand-off solder joint
GB2603488A (en) * 2021-02-04 2022-08-10 Rockwood Composites A soldering compound

Also Published As

Publication number Publication date
GB2103980B (en) 1986-01-22

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee