GB2132538A - Method of soldering a conductive element to a conductor pad - Google Patents

Method of soldering a conductive element to a conductor pad Download PDF

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Publication number
GB2132538A
GB2132538A GB08328914A GB8328914A GB2132538A GB 2132538 A GB2132538 A GB 2132538A GB 08328914 A GB08328914 A GB 08328914A GB 8328914 A GB8328914 A GB 8328914A GB 2132538 A GB2132538 A GB 2132538A
Authority
GB
United Kingdom
Prior art keywords
solder
conductor pad
areas
conductive element
soldering
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
GB08328914A
Other versions
GB2132538B (en
GB8328914D0 (en
Inventor
Ernest Bourne
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.)
Fujitsu Services Ltd
Original Assignee
Fujitsu Services Ltd
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 Fujitsu Services Ltd filed Critical Fujitsu Services Ltd
Priority to GB08328914A priority Critical patent/GB2132538B/en
Publication of GB8328914D0 publication Critical patent/GB8328914D0/en
Publication of GB2132538A publication Critical patent/GB2132538A/en
Application granted granted Critical
Publication of GB2132538B publication Critical patent/GB2132538B/en
Expired legal-status Critical Current

Links

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
    • B23K1/20—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
    • H05K3/3485—Applying solder paste, slurry or powder
    • 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
    • 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
    • H05K2203/04—Soldering or other types of metallurgic bonding
    • H05K2203/043—Reflowing of solder coated conductors, not during connection of components, e.g. reflowing solder paste
    • 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
    • H05K2203/05—Patterning and lithography; Masks; Details of resist
    • H05K2203/0502—Patterning and lithography
    • H05K2203/0545—Pattern for applying drops or paste; Applying a pattern made of drops or paste
    • 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

Abstract

Solder is pre-applied to a conductor pad (1) on a printed circuit board (4) in a pattern of discrete areas (2), e.g. by screen printing with solder paste which is melted and allowed to solidify. Thereafter a conductive element (5), e.g. a component terminal, is brought into contact with said areas of solder which are then melted and allowed to solidify. <IMAGE>

Description

SPECIFICATION Improvements in or relating to methods of soldering The present invention relates to soldering a conductive element to a conductor pad.
Such conductor pads may be provided on the surface of a printed circuit board, for example, to facilitate the connection thereto of another component. The conductor pads are electrically connected to conductors on the printed circuit board to thereby provide conductive areas to which terminations of the component are attached by soldering.
It has previously been proposed to utilise a method of soldering a conductive element to a conductor pad in which the conductor pad is precoated with a layer of so called solder paste which is subsequently melted and then allowed to solidify. When the conductive element is required to be soldered to the conductor pad the solidified solder is caused to reflow by the application of heat. However, a disadvantage of this method is that, on reflowing, the solder has a tendency to spread beyond the boundary of the conductor pad and to cause short circuits between the pad and adjacent pads or conductive tracks.
According to the present invention a method of soldering a conductive element to a conductor pad includes the steps of; forming a plurality of discrete areas of solder on said conductor pad; bringing said conductive element into contact with the areas of solder on the conductor pad; causing the areas of solder to melt by the application of heat thereto; and thereafter allowing the molten solder to solidify to thereby solder the conductive element to the conductor pad.
A method of soldering a conductive element to a conductor pad will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1, shows a conductor pad carrying discrete areas of solder, Figure 2, is a side view of the conductor pad showing a conductive element positioned thereon, and Figure 3, shows the conductive element soldered to the conductor pad.
Referring to Figurel of the drawings, a conductor pad 1 is shown carrying a number of discrete areas of solder 2. The conductor pad 1 is formed on the surface of a printed circuit board (not shown in Figure 1) and is connected to a conductive track on the printed circuit board. Part of the conductive track is shown and is indicated by the reference numeral 3.
The areas of solder 2, which may for example be in the form of round dots, are formed from a solder paste which is produced by mixing a tin/lead alloy in powder form with a flux. The paste is then printed through a screen on to the conductor pad 1. The deposition of solder paste by such a screen printing method is known and provides a convenient way of forming the discrete areas.
After the areas of solder paste have been deposited on to the conductor pad, the pad is first of all heated to cause the areas of solder paste to melt and is then allowed to cool to produce discrete areas of solidified solder.
Typical dimensions of a conductor pad and solder areas is as follows:~ Pad size 1.130 in.x0.030 in.
So!der areas 0.020 in. dia. dots.
Number of solder 5 areas per pad Spacing between 0.005 in.
solder areas Figure 2 shows the conductor pad 1 on a printed circuit board 4 and a conductive element 5 placed on the pad 1 in preparation for the soldering operation. The conductive element 5 may be, for example, a termination of a component.
Figure 3 shows the conductive element 5 soldered to the conductor pad 1. The soldering operation is carried out by applying heat to the conductive element and/or the conductor pad to cause the areas of solidified solder to reflow. After cooling, the conductive element is secured to the conductor pad. It will be noted that the solder remains within the boundary of the conductor pad, as indicated at 6. It is believed that, by providing the solder in the form of relatively small discrete areas, the surface tension of the melted solder is higher than would be the case if the solder was in the form of a single larger area. This tends to reduce the spread of the molten solder causing it to remain within the boundary of the conductor pad.
It will be understood that the typical dimensions given for the pad and solder areas is by way of example only and that the invention is equally applicable when the conductor pads and solder areas are of other dimensions.
It will be realised that the areas of solder paste may be applied to the conductor pad by methods other than screen printing. Furthermore, it will also be realised that it is not an essential feature of the invention that the solder must be in the form of solder paste. For example, conventional solder, applied in a molten state, could in some circumstances be used.

Claims (6)

Claims
1. A method of soldering a conductive element to a conductor pad including the steps of; forming a plurality of discrete areas of solder on said conductor pad; bringing said conductive element into contact with the areas of solder on the conductor pad; causing the areas of solder to melt by the application of heat thereto; and thereafter allowing the molten solder to solidify to thereby solder the conductive element to the conductor pad.
2. A method as claimed in Claim 1, in which the step of; forming said plurality of discrete areas of solder on the conductor pad includes; screen printing said discrete areas with a solder paste; causing the areas of solder paste to melt by the application of heat thereto; and thereafter allowing the molten areas of solder to solidify.
3. A method as claimed in Claim 1 or 2, in which the conductor pad is on the surface of a printed circuit board and is connected to at least one conductive track on the surface of the printed circuit board.
4. A method as claimed in Claim 1, 2 or 3, in which the areas of solder are in the form of round dots.
5. A method carried out as hereinbefore described with reference to the accompanying drawing.
6. A structure including a conductive element soldered TO a conductor pad by the method as claimed in any preceding claim.
GB08328914A 1982-11-20 1983-10-28 Method of soldering a conductive element to a conductor pad Expired GB2132538B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08328914A GB2132538B (en) 1982-11-20 1983-10-28 Method of soldering a conductive element to a conductor pad

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8233178 1982-11-20
GB08328914A GB2132538B (en) 1982-11-20 1983-10-28 Method of soldering a conductive element to a conductor pad

Publications (3)

Publication Number Publication Date
GB8328914D0 GB8328914D0 (en) 1983-11-30
GB2132538A true GB2132538A (en) 1984-07-11
GB2132538B GB2132538B (en) 1986-05-08

Family

ID=26284458

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08328914A Expired GB2132538B (en) 1982-11-20 1983-10-28 Method of soldering a conductive element to a conductor pad

Country Status (1)

Country Link
GB (1) GB2132538B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236217A (en) * 1989-08-23 1991-03-27 Itt Ind Ltd Improvement relating to electrical connectors
EP0854548A2 (en) * 1997-01-15 1998-07-22 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Electric contact device
EP0859540A1 (en) * 1997-02-06 1998-08-19 TDK Corporation Method and apparatus for screen printing and soldering an electronic component onto a printed circuit board
EP0907308A1 (en) * 1996-05-29 1999-04-07 Rohm Co., Ltd. Method for mounting terminal on circuit board and circuit board

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB228190A (en) * 1924-01-25 1925-07-09 British Thomson Houston Co Ltd Improvements in and relating to methods of brazing
GB422055A (en) * 1933-07-04 1935-01-04 Broughton Copper Company Ltd Improvements in and relating to electric wire conduits
GB514882A (en) * 1937-02-16 1939-11-20 Ver Gluehlampen & Elek Ag Process for hard soldering metal bodies, especially the anodes of electric discharge tubes
GB703003A (en) * 1951-02-19 1954-01-27 British Insulated Callenders Improvements in the manufacture of a metal tube which may form part of an electric cable
GB1099906A (en) * 1964-06-26 1968-01-17 Ibm Improvements in or relating to methods of making electrical connections
GB1234821A (en) * 1967-09-08 1971-06-09 Bunker Ramo Interconnection by bonding of stacked sheets
EP0041928A1 (en) * 1980-05-27 1981-12-16 TECHNICONSULT S.r.l. A method to braze by the Joule effect an electroconductive element onto a silk-screen printed support or the like as well as a device and product relating the same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB228190A (en) * 1924-01-25 1925-07-09 British Thomson Houston Co Ltd Improvements in and relating to methods of brazing
GB422055A (en) * 1933-07-04 1935-01-04 Broughton Copper Company Ltd Improvements in and relating to electric wire conduits
GB514882A (en) * 1937-02-16 1939-11-20 Ver Gluehlampen & Elek Ag Process for hard soldering metal bodies, especially the anodes of electric discharge tubes
GB703003A (en) * 1951-02-19 1954-01-27 British Insulated Callenders Improvements in the manufacture of a metal tube which may form part of an electric cable
GB1099906A (en) * 1964-06-26 1968-01-17 Ibm Improvements in or relating to methods of making electrical connections
GB1234821A (en) * 1967-09-08 1971-06-09 Bunker Ramo Interconnection by bonding of stacked sheets
EP0041928A1 (en) * 1980-05-27 1981-12-16 TECHNICONSULT S.r.l. A method to braze by the Joule effect an electroconductive element onto a silk-screen printed support or the like as well as a device and product relating the same

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236217A (en) * 1989-08-23 1991-03-27 Itt Ind Ltd Improvement relating to electrical connectors
EP0907308A1 (en) * 1996-05-29 1999-04-07 Rohm Co., Ltd. Method for mounting terminal on circuit board and circuit board
EP0907308A4 (en) * 1996-05-29 2005-03-30 Rohm Co Ltd Method for mounting terminal on circuit board and circuit board
EP0854548A2 (en) * 1997-01-15 1998-07-22 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Electric contact device
EP0854548A3 (en) * 1997-01-15 1999-06-16 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Electric contact device
EP0859540A1 (en) * 1997-02-06 1998-08-19 TDK Corporation Method and apparatus for screen printing and soldering an electronic component onto a printed circuit board
US6036084A (en) * 1997-02-06 2000-03-14 Tdk Corporation Screen printing method and apparatus therefor, and electronic component soldering method using screen printing and apparatus therefor

Also Published As

Publication number Publication date
GB2132538B (en) 1986-05-08
GB8328914D0 (en) 1983-11-30

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Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19951028