EP0996770A1 - Method and apparatus for treating metal surfaces by dry process - Google Patents

Method and apparatus for treating metal surfaces by dry process

Info

Publication number
EP0996770A1
EP0996770A1 EP99914612A EP99914612A EP0996770A1 EP 0996770 A1 EP0996770 A1 EP 0996770A1 EP 99914612 A EP99914612 A EP 99914612A EP 99914612 A EP99914612 A EP 99914612A EP 0996770 A1 EP0996770 A1 EP 0996770A1
Authority
EP
European Patent Office
Prior art keywords
gas
treatment
flow
excited
pressure
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.)
Withdrawn
Application number
EP99914612A
Other languages
German (de)
French (fr)
Inventor
Denis Verbockhaven
Stéphane Rabia
Thierry Sindzingre
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.)
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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 Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Publication of EP0996770A1 publication Critical patent/EP0996770A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
    • 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
    • B23K1/206—Cleaning
    • 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
    • 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
    • H05K3/3489—Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces

Definitions

  • the present invention relates to a method of surface treatment by the dry route of at least one portion of metal surface, of the kind where the portion is treated at a pressure close to atmospheric pressure with a treatment gas comprising excited or unstable.
  • Such surface treatments can, for example, occur during the production or recovery processes for flat products or hollow bodies, in the production of electronic circuits such as printed circuit boards, to perform cleaning or fluxing, degreasing or still surface activation, often before a subsequent process, which may for example be annealing, 1 * plating of zinc, aluminum, tin or their alloys, soldering (for example of electronic components on the wafer circuit board), or the deposition of organic coatings such as varnishes or paints, or inorganic coatings such as nitrides or films based on silicon.
  • these steps for treating metal surfaces include pickling, cleaning, deburring of connection holes (“desmearing”) or fluxing before tinning or soldering.
  • a solder paste containing a mixture of metal alloy and flux is deposited on the printed circuit at the component connection locations, then the components are placed on the plate.
  • the plate provided with the components is then inserted into a reflow oven so as to provide an amount of heat necessary to allow the melting of the metal alloy, as well as the activation of the fluxing element contained in the paste.
  • Wave soldering consists in bringing the plates carrying the electronic components to be brazed into contact with one or more waves of liquid solder alloy obtained by circulation of a solder bath contained in a tank, by means of a buzzard.
  • the circuits are previously fluxed in an area upstream of the wave soldering machine, using a flux spray or a flow foam, then preheated so as to activate the previously deposited fluxes, so as to clean the surfaces to be brazed, to remove oxides, organic contaminants.
  • One of the objectives of the present invention is to propose such improvements.
  • this objective is achieved in that the excited or unstable species have a speed component substantially perpendicular to the surface.
  • the subject of the invention is therefore a method of surface treatment by the dry route of at least one portion of metal surface, according to which the portion is treated at a pressure close to the pressure atmospheric by a flow of process gas comprising excited or unstable species, characterized in that the pressure of the process gas on the metal surface is increased locally so as to force the chemical species to move in a direction substantially perpendicular to said surface.
  • the process according to the invention can also include one or more of the following characteristics: - the treatment gas is substantially free of electrically charged species; the treatment gas is obtained from a primary gas mixture and, where appropriate, from an adjacent gas mixture, the primary gas mixture being obtained at the gas outlet of at least one apparatus for forming excited gas species or unstable, in which an initial gas mixture comprising an inert gas and / or a reducing gas and / or an oxidizing gas has been transformed, the adjacent mixture not having passed through the apparatus; the flow of treatment gas being emitted in the direction of the surface in a direction generally perpendicular thereto, and comprising, at the periphery of the excited or unstable particles animated by a movement in a direction substantially tangent to the surface, the pressure the flow of process gas on the surface is increased at the periphery of the flow;
  • the pressure of the treatment gas on the surface is increased by means of at least one flow of entrainment gas injected perpendicular to the surface; - the entrainment gas comprises nitrogen;
  • the surface portion to be treated being arranged " in a treatment chamber, the pressure of the treatment gas on the surface is increased by means of at least one fan turned towards the surface so as to force the flow of gas of treatment to strike the surface in a direction substantially perpendicular to the latter;
  • the treatment gas comprising the excited or unstable chemical species is produced from an initial reducing gas mixture comprising nitrogen and hydrogen.
  • An example of an apparatus for forming excited or unstable gaseous species is described in the document EP-658391 already cited.
  • the invention also relates to a method of wave soldering of electronic components on an electronic circuit, during which:
  • the components are placed on connection locations provided on the circuit,
  • a circuit fluxing operation is carried out by treatment of the latter, at a pressure close to atmospheric pressure, by means of a flow of treatment gas comprising excited or unstable chemical species, and
  • the circuit carrying the components is brought into contact with at least one wave of a solder alloy, characterized in that during the fluxing operation of the electronic circuit, the pressure of the treatment gas is locally increased on the circuit so as to force the chemical species to move in a direction substantially perpendicular to the circuit.
  • the invention also relates to an apparatus for treating at least a portion of metal surface by the dry route, "for the implementation of a method as defined above, characterized in that it comprises a source of treatment gas comprising excited or unstable chemical species, a device for conveying parts comprising said at least one portion of metal surface, making it possible to bring the parts into contact with a flow of treatment gas, characterized in that it comprises means for locally increasing the pressure of the treatment gas on each part, so as to force the chemical species to move in a direction substantially perpendicular to the latter.
  • the invention also relates to a wave soldering device of electronic components on an electronic circuit, for the implementation of a method as defined above, characterized in that it comprises a device for conveying circuits through at least one device for fluxing circuits, by treatment of the latter by means of a flow of treatment gas comprising excited or unstable chemical species, said circuits carrying on at least one of their faces the components to be brazed on connection locations for the latter, then through a tank containing a solder alloy for soldering the components, and in that at least one of said fluxing devices includes means for locally increasing the pressure of the gas flow from treatment on each circuit, so as to force the chemical species to move in a direction substantially perpendicular to the latter.
  • FIG. 1 is a schematic representation of a wave soldering apparatus according to l 'invention
  • FIG. 2 is a schematic sectional view of a device for forming excited or unstable chemical species used in the constitution of fluxing device of the wave soldering apparatus of Figure 1;
  • FIG. 3 represents a first embodiment of the means for locally increasing the pressure of the treatment gas on a part;
  • FIG. 4 illustrates a second embodiment of the means for locally increasing the pressure of the treatment gas on a part.
  • a wave soldering device comprises for the embodiment shown a device 10 for conveying circuits 12 (here for example printed circuit boards), a first station 14 for preheating the wafers, to a device 16 for processing the wafers 12 before brazing, by treatment of the latter with excited or unstable chemical species, then to a station 18 for wave soldering at the level of which the wafers, carrying the electronic components to be soldered, are brought into contact with at least one wave of a solder alloy.
  • the conveying device 10 comprises one or more transfer belts, such as 20, illustrated in phantom in this figure, on which the printed circuit boards 12 are arranged.
  • Each plate 12 is here provided with a set of through holes in which are inserted the tabs of the electronic components, such as 22 and 24, which should be soldered. As can be seen in Figure 1, the carpet
  • the plates 12, disposed on the mat 20 are first transferred from the first preheating station 14 at which an appropriate heat treatment device 28 is disposed, then to the second fluxing station 16 at which the wafers undergo a decontamination and deoxidation operation by bringing the wafers into contact with excited or unstable gaseous species.
  • the plates thus flowed are then brought into contact with at least one wave 30 of solder alloy, at the level of the soldering station 18, which wave 30 is obtained by pumping a solder bath contained in a tank 32, through of a nozzle 34.
  • the excited or unstable gaseous species, coming to treat the wafers 12 at the fluxing station 16, are here obtained by passing an appropriate initial gas, for example a reducing gas mixture containing for example nitrogen and hydrogen, through a device, such as 36, for forming excited or unstable chemical species, by passing the initial gas through an electrical discharge.
  • an appropriate initial gas for example a reducing gas mixture containing for example nitrogen and hydrogen
  • each device 36 for forming excited or unstable chemical species comprises, for the embodiment shown, a first tubular electrode 37, formed for example by an internal face of a metal block 38, and in which is concentrically arranged an assembly formed of a tube of dielectric material 40 for example ceramic, on the internal face of which is deposited, by metallization, a second electrode 41 excessively thickened in Figure 2, to improve clarity.
  • the dielectric tube 40 and the second electrode 41 define, with the first electrode 37, a tubular gas passage 42, and, internally, an internal volume 44 in which a refrigerant is circulated.
  • the block 38 comprises, diametrically opposite, two longitudinal slots 46 and 48 respectively forming the inlet of the initial gas to be excited in the passage 42 and the output of the treatment gas flow comprising the excited or unstable gaseous species.
  • the block 38 also advantageously comprises, at the periphery of the first electrode 37, a plurality of conduits, such as 50, for the passage a refrigerant, for example water.
  • the gas inlet slot 46 communicates with a homogenization chamber 52 formed in a housing 54 attached to the block 38 and comprising a pipe 56 for supplying initial gas.
  • the module is completed by an electric generator 58 at high voltage and high frequency intended to generate a discharge in the gaseous mixture circulating in the gas passage 42 so as to cause, an excitation of the gaseous molecules entering into its constitution and thus generating at output 48, a treatment gas mixture comprising excited or unstable chemical species but being substantially free of electrically charged species, which deoxidize and decontaminate the external surface of the printed circuit boards 20 (FIG. 1).
  • an electric generator 58 at high voltage and high frequency intended to generate a discharge in the gaseous mixture circulating in the gas passage 42 so as to cause, an excitation of the gaseous molecules entering into its constitution and thus generating at output 48, a treatment gas mixture comprising excited or unstable chemical species but being substantially free of electrically charged species, which deoxidize and decontaminate the external surface of the printed circuit boards 20 (FIG. 1).
  • the wafers are here in a post-discharge situation.
  • each device 36 for forming excited or unstable chemical species generates, at the outlet, a gas flow comprising chemical species emitted in a direction generally perpendicular to the surface of the wafers 12 to be treated.
  • the gas flow comprising the chemical species intended to ensure the fluxing of the wafer naturally tends to flare, so that the particles located in periphery of the flow tend to move in a direction substantially parallel to the surface of the wafer.
  • this portion of flux has a lower efficiency for the treatment of holes made in the plate for mounting the components.
  • the excited particles are forced to propagate substantially perpendicular to the wafer so as to come to engage in the holes.
  • the pressure is increased locally, on each plate 12, of the flow of gas containing the chemical species. More preferably, insofar as the particles in question are located at the periphery of the treatment flow, the pressure of the treatment flow is increased at the periphery of the flow.
  • the pressure of the activated gas flow is increased by using a jet of auxiliary driving gas (not passing through the electrical discharge), for example nitrogen or a gas identical to that used to generate the excited particles, for example nitrogen mixed with hydrogen and, where appropriate, steam.
  • auxiliary driving gas for example nitrogen or a gas identical to that used to generate the excited particles, for example nitrogen mixed with hydrogen and, where appropriate, steam.
  • the jet of drive gas is generated by means of a drive device 60, adapted to project the drive gas, taken from an enclosure 62, in a direction substantially parallel to the axis of the holes, that is to say perpendicular to the surface to be treated, as shown by the arrows F, and this with a relatively high speed, for example between 10 and 100 m / s.
  • the means 60 could for example consist of a knife with a venturi effect or a flow amplifier.
  • the width of the area treated by the flow of excited particles is thus considerably improved.
  • each plate being located at the level of the fluxing station 16, in a preferably sealed enclosure, the pressure of the treatment gas on the plate is increased by means of at least one fan. 64 turned towards the wafer and disposed at the periphery of the gas flow so as to force, in this zone, the flow of treatment gas to move in a direction substantially perpendicular to the wafer.
  • the entrainment gas is taken from the treatment gas present in the enclosure.

Abstract

The invention concerns a dry process surface treatment method for treating at least a metal surface portion, wherein the portion is treated at a pressure close to atmospheric pressure with a treating gas stream comprising excited and unstable species, which consists in locally increasing the treating gas pressure on the metal surface portion so as to force the l species to move along a direction substantially perpendicular to the surface. The invention is useful for wave brazing electronic components on printed circuit wafers.

Description

Procédé et appareil de traitement de surfaces métalliques par voie sèche Method and apparatus for treating metallic surfaces by the dry route
La présente invention est relative à un procédé de traitement de surface par voie sèche d'au moins une portion de surface métallique, du genre où la portion est traitée à une pression voisine de la pression atmosphérique par un gaz de traitement comprenant des espèces excitées ou instables. De tels traitements de surface peuvent par exemple intervenir au cours des procédés de production ou de valorisation de produits plats ou corps creux, dans la production de circuits électroniques tels les plaquettes de circuits imprimés, pour réaliser des fonctions de nettoyage ou fluxage, de dégraissage ou encore d'activation de surface, souvent avant un procédé ultérieur, qui peut être par exemple un recuit, 1 * électrodéposition de zinc, d'aluminium, d'étain ou de leurs alliages, un brasage (par exemple de composants électroniques sur la plaquette de circuit imprimé) , ou encore le dépôt de revêtements organiques tels vernis ou peintures, ou inorganiques tels nitrures ou films à base de silicium.The present invention relates to a method of surface treatment by the dry route of at least one portion of metal surface, of the kind where the portion is treated at a pressure close to atmospheric pressure with a treatment gas comprising excited or unstable. Such surface treatments can, for example, occur during the production or recovery processes for flat products or hollow bodies, in the production of electronic circuits such as printed circuit boards, to perform cleaning or fluxing, degreasing or still surface activation, often before a subsequent process, which may for example be annealing, 1 * plating of zinc, aluminum, tin or their alloys, soldering (for example of electronic components on the wafer circuit board), or the deposition of organic coatings such as varnishes or paints, or inorganic coatings such as nitrides or films based on silicon.
Dans le domaine de la fabrication des plaquettes de circuit imprimé, ces étapes de traitement de surfaces métalliques sont notamment du décapage, nettoyage, ébavurage des trous de connexion (« desmearing ») ou encore fluxage avant étamage ou brasage.In the field of manufacturing printed circuit boards, these steps for treating metal surfaces include pickling, cleaning, deburring of connection holes ("desmearing") or fluxing before tinning or soldering.
Des exemples de tels procédés de traitement de surface par voie sèche sont rapportés dans les documents suivants : EP-658391 et EP-658637.Examples of such dry surface treatment methods are reported in the following documents: EP-658391 and EP-658637.
Pour ce qui est du brasage de composants électroniques sur circuit électronique, notamment sur plaquettes de circuits imprimés, les deux méthodes les plus couramment utilisées pour effectuer une telle opération de brasage, sont le " brasage à la vague" et le "brasage par refusion".As regards the soldering of electronic components on an electronic circuit, in particular on printed circuit boards, the two most commonly used methods for performing such a brazing operation, are "wave soldering" and "reflow soldering".
Dans la technique de brasage par refusion, une pâte à braser contenant un mélange d'alliage métallique et de flux est déposé sur le circuit imprimé en des emplacements de connexion des composants, puis les composants sont placés sur la plaque. La plaque munie des composants est ensuite insérée dans un four à refusion de manière à apporter une quantité de chaleur nécessaire pour permettre d'obtenir la fusion de l'alliage métallique, ainsi que l'activation de l'élément fluxant contenu dans la pâte.In the reflow soldering technique, a solder paste containing a mixture of metal alloy and flux is deposited on the printed circuit at the component connection locations, then the components are placed on the plate. The plate provided with the components is then inserted into a reflow oven so as to provide an amount of heat necessary to allow the melting of the metal alloy, as well as the activation of the fluxing element contained in the paste.
Le brasage à la vague consiste quant à lui à amener les plaquettes portant les composants électroniques à braser en contact avec une ou plusieurs vagues d'alliage de soudure liquide obtenues par circulation d'un bain de soudure contenu dans un bac, au moyen d'une buse.Wave soldering consists in bringing the plates carrying the electronic components to be brazed into contact with one or more waves of liquid solder alloy obtained by circulation of a solder bath contained in a tank, by means of a buzzard.
Généralement, les circuits sont préalablement fluxés dans une zone amont de la machine de brasage à la vague, à l'aide d'un spray de flux ou d'une mousse de flux, puis préchauffés de manière à activer les flux précédemment déposés, de manière à nettoyer les surfaces à braser, pour l'élimination des oxydes, des contaminants organiques.Generally, the circuits are previously fluxed in an area upstream of the wave soldering machine, using a flux spray or a flow foam, then preheated so as to activate the previously deposited fluxes, so as to clean the surfaces to be brazed, to remove oxides, organic contaminants.
Comme pour le brasage par refusion, afin que l'alliage vienne mouiller les métallisations et former les connexions, il est nécessaire de procéder à un décapage des métallisations, c'est-à-dire de la plaquette de circuit imprimé et des composants qu'elle porte. Ce décapage est généralement effectué par un agent qui peut se présenter sous forme liquide ou gazeuse.As with reflow soldering, in order for the alloy to wet the metallizations and form the connections, it is necessary to strip the metallizations, that is to say the printed circuit board and the components that she wears. This pickling is generally carried out by an agent which can be in liquid or gaseous form.
Pour procéder à un décapage par voie gazeuse, on peut utiliser un flux de gaz contenant des espèces chimiques excitées ou instables, dirigé vers le circuit imprimé, ce flux venant décaper les métallisations avant l'étape de brasage.To carry out a pickling by gas, one can use a gas flow containing excited or unstable chemical species, directed towards the circuit printed, this flux coming to strip the metallizations before the soldering step.
Dans ce domaine du fluxage par voie sèche de surfaces métalliques avant brasage ou étamage, les travaux menés à bien par la Demanderesse ont montré qu'afin d'obtenir un décapage efficace, il est nécessaire que les espèces chimiques viennent traiter toutes les métallisations, incluant les trous ménagés dans les emplacements de connexion de la plaquette et, d'autre part, les pattes des composants insérés « through hole componentε » en anglais) .In this field of dry fluxing of metal surfaces before brazing or tinning, the work carried out by the Applicant has shown that in order to obtain an effective pickling, it is necessary that the chemical species come to treat all the metallizations, including the holes in the connection locations of the wafer and, on the other hand, the tabs of the components inserted "through hole componentε" in English).
Il apparaît alors que selon les méthodes actuellement disponibles de traitement par voie sèche, bien que le flux de gaz venant traiter la plaquette de circuit imprimé soit généralement émis selon une direction sensiblement perpendiculaire à celle-ci, le flux tend naturellement à s'écraser de sorte que les particules, et en particulier les particules situées en périphérie, tendent à se déplacer tangentiellement à la surface de la plaquette.It then appears that according to the methods currently available for dry processing, although the flow of gas coming to treat the printed circuit board is generally emitted in a direction substantially perpendicular thereto, the flow naturally tends to collapse by so that the particles, and in particular the particles located on the periphery, tend to move tangentially to the surface of the wafer.
On conçoit donc que ce type de technique de décapage doive être encore amélioré, notamment en vue d'assurer de façon plus efficace et systématique le décapage des trous ménagés dans la plaquette pour l'insertion des pattes de composants électroniques dits « à fil » ou « à insérer ».It is therefore understandable that this type of pickling technique must be further improved, in particular in order to ensure more efficient and systematic pickling of the holes made in the wafer for the insertion of the legs of so-called "wire" electronic components or "To insert".
Un des objectifs de la présente invention est de proposer de telles améliorations.One of the objectives of the present invention is to propose such improvements.
Cet objectif est selon l'invention atteint en ce que les espèces excitées ou instables possèdent une composante de vitesse substantiellement perpendiculaire à la surface.According to the invention, this objective is achieved in that the excited or unstable species have a speed component substantially perpendicular to the surface.
L'invention a donc pour objet un procédé de traitement de surface par voie sèche d'au moins une portion de surface métallique, selon lequel la portion est traitée à une pression voisine de la pression atmosphérique par un flux de gaz de traitement comprenant des espèces excitées ou instables, caractérisé en ce que l'on augmente localement la pression du gaz de traitement sur la surface métallique de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à ladite surface.The subject of the invention is therefore a method of surface treatment by the dry route of at least one portion of metal surface, according to which the portion is treated at a pressure close to the pressure atmospheric by a flow of process gas comprising excited or unstable species, characterized in that the pressure of the process gas on the metal surface is increased locally so as to force the chemical species to move in a direction substantially perpendicular to said surface.
Le procédé suivant 1 ' invention peut en outre comporter une ou plusieurs des caractéristiques suivantes : - le gaz de traitement est substantiellement dépourvu d ' espèces électriquement chargées ; le gaz de traitement est obtenu à partir d'un mélange gazeux primaire et le cas échéant d'un mélange gazeux adjacent, le mélange gazeux primaire étant obtenu à la sortie de gaz d'au moins un appareil de formation d'espèces gazeuses excitées ou instables, dans lequel a été transformé un mélange gazeux initial comprenant un gaz inerte et/ou un gaz réducteur et/ou un gaz oxydant, le mélange adjacent n'ayant pas transité par l'appareil ; - le flux de gaz de traitement étant émis en direction de la surface selon une direction généralement perpendiculaire à celle-ci, et comportant, en périphérie des particules excitées ou instables animées d'un mouvement selon une direction sensiblement tangente à la surface, la pression du flux de gaz de traitement sur la surface est augmentée en périphérie du flux ;The process according to the invention can also include one or more of the following characteristics: - the treatment gas is substantially free of electrically charged species; the treatment gas is obtained from a primary gas mixture and, where appropriate, from an adjacent gas mixture, the primary gas mixture being obtained at the gas outlet of at least one apparatus for forming excited gas species or unstable, in which an initial gas mixture comprising an inert gas and / or a reducing gas and / or an oxidizing gas has been transformed, the adjacent mixture not having passed through the apparatus; the flow of treatment gas being emitted in the direction of the surface in a direction generally perpendicular thereto, and comprising, at the periphery of the excited or unstable particles animated by a movement in a direction substantially tangent to the surface, the pressure the flow of process gas on the surface is increased at the periphery of the flow;
- la pression du gaz de traitement sur la surface est augmentée au moyen d'au moins un flux de gaz d'entraînement injecté perpendiculairement à la surface ; - le gaz d'entraînement comporte de l'azote ;the pressure of the treatment gas on the surface is increased by means of at least one flow of entrainment gas injected perpendicular to the surface; - the entrainment gas comprises nitrogen;
- en variante, la portion de surface à traiter étant disposée " dans une chambre de traitement, la pression du gaz de traitement sur la surface est augmentée au moyen d'au moins un ventilateur tourné vers la surface de manière à forcer le flux de gaz de traitement à venir frapper le surface selon une direction sensiblement perpendiculairement à cette dernière ;- as a variant, the surface portion to be treated being arranged " in a treatment chamber, the pressure of the treatment gas on the surface is increased by means of at least one fan turned towards the surface so as to force the flow of gas of treatment to strike the surface in a direction substantially perpendicular to the latter;
- les espèces chimiques excitées ou instables sont obtenues par passage d'un gaz initial dans une décharge électrique ; et- the excited or unstable chemical species are obtained by passing an initial gas through an electric discharge; and
- le gaz de traitement comportant les espèces chimiques excitées ou instables est produit à partir d'un mélange gazeux initial réducteur comprenant de l'azote et de 1 ' hydrogène. Un exemple d'appareil de formation d'espèces gazeuses excitées ou instables est décrit dans le document EP-658391 déjà cité.the treatment gas comprising the excited or unstable chemical species is produced from an initial reducing gas mixture comprising nitrogen and hydrogen. An example of an apparatus for forming excited or unstable gaseous species is described in the document EP-658391 already cited.
L'invention concerne également un procédé de brasage à la vague de composants électroniques sur circuit électronique, au cours duquel :The invention also relates to a method of wave soldering of electronic components on an electronic circuit, during which:
- on place les composants sur des emplacements de connexion ménagés sur le circuit,the components are placed on connection locations provided on the circuit,
- on effectue une opération de fluxage du circuit par traitement de ce dernier, à une pression voisine de la pression atmosphérique, au moyen d'un flux de gaz de traitement comportant des espèces chimiques excitées ou instables, eta circuit fluxing operation is carried out by treatment of the latter, at a pressure close to atmospheric pressure, by means of a flow of treatment gas comprising excited or unstable chemical species, and
- on met le circuit portant les composants en contact avec au moins une vague d'un alliage de soudure, caractérisé en ce qu'au cours de l'opération de fluxage du circuit électronique, on augmente localement la pression du gaz de traitement sur le circuit de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire au circuit. L'invention a également pour objet un appareil de traitement d'au moins une portion de surface métallique par voie sèche," pour la mise en oeuvre d'un procédé tel que défini ci-dessus, caractérisé en ce qu'il comporte une source de gaz de traitement comportant des espèces chimiques excitées ou instables, un dispositif de convoyage de pièces comportant ladite au moins une portion de surface métallique, permettant d'amener les pièces en contact avec un flux de gaz de traitement, caractérisé en ce qu'il comporte des moyens pour augmenter localement la pression du gaz de traitement sur chaque pièce, de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à cette dernière.- the circuit carrying the components is brought into contact with at least one wave of a solder alloy, characterized in that during the fluxing operation of the electronic circuit, the pressure of the treatment gas is locally increased on the circuit so as to force the chemical species to move in a direction substantially perpendicular to the circuit. The invention also relates to an apparatus for treating at least a portion of metal surface by the dry route, " for the implementation of a method as defined above, characterized in that it comprises a source of treatment gas comprising excited or unstable chemical species, a device for conveying parts comprising said at least one portion of metal surface, making it possible to bring the parts into contact with a flow of treatment gas, characterized in that it comprises means for locally increasing the pressure of the treatment gas on each part, so as to force the chemical species to move in a direction substantially perpendicular to the latter.
L'invention a également pour objet un appareil de brasage à la vague de composants électroniques sur circuit électronique, pour la mise en oeuvre d'un procédé tel que défini ci-dessus, caractérisé en ce qu'il comporte un dispositif de convoyage de circuits à travers au moins un dispositif de fluxage de circuits, par traitement de ces derniers au moyen d'un flux de gaz de traitement comportant des espèces chimiques excitées ou instables, lesdits circuits portant sur au moins une de leur face les composants à braser sur des emplacements de connexion de ces derniers, puis à travers un bac contenant un alliage de soudure en vue du brasage des composants, et en ce que au moins l'un desdits dispositifs de fluxage comporte des moyens pour augmenter localement la pression du flux de gaz de traitement sur chaque circuit, de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à ce dernier.The invention also relates to a wave soldering device of electronic components on an electronic circuit, for the implementation of a method as defined above, characterized in that it comprises a device for conveying circuits through at least one device for fluxing circuits, by treatment of the latter by means of a flow of treatment gas comprising excited or unstable chemical species, said circuits carrying on at least one of their faces the components to be brazed on connection locations for the latter, then through a tank containing a solder alloy for soldering the components, and in that at least one of said fluxing devices includes means for locally increasing the pressure of the gas flow from treatment on each circuit, so as to force the chemical species to move in a direction substantially perpendicular to the latter.
D ' autres caractéristiques et avantages ressortiront de la description suivante, donnée uniquement à titre d'exemple, et faite en référence aux dessins annexés sur lesquels : - la figure 1 est une représentation schématique d'un appareil de brasage à la vague conforme à l'invention;Other characteristics and advantages will emerge from the following description, given solely by way of example, and made with reference to the appended drawings in which: - Figure 1 is a schematic representation of a wave soldering apparatus according to l 'invention;
- la figure 2 est une représentation schématique en coupe d'un dispositif de formation d'espèces chimiques excitées ou instables entrant dans la constitution du dispositif de fluxage de l'appareil de brasage à la vague de figure 1; la figure 3 représente un premier mode de réalisation des moyens pour augmenter localement la pression du gaz de traitement sur une pièce ; et la figure 4 illustre un deuxième mode de réalisation des moyens pour augmenter localement la pression du gaz de traitement sur une pièce.- Figure 2 is a schematic sectional view of a device for forming excited or unstable chemical species used in the constitution of fluxing device of the wave soldering apparatus of Figure 1; FIG. 3 represents a first embodiment of the means for locally increasing the pressure of the treatment gas on a part; and FIG. 4 illustrates a second embodiment of the means for locally increasing the pressure of the treatment gas on a part.
En référence à la figure 1, un appareil de brasage à la vague conforme à l'invention, comporte pour le mode de réalisation représenté un dispositif 10 de convoyage de circuits 12 (ici par exemple des plaquettes de circuit imprimé) , d'un premier poste 14 de préchauffage des plaquettes, vers un dispositif 16 de traitement des plaquettes 12 avant brasage, par traitement de ces dernières au moyen d'espèces chimiques excitées ou instables, puis vers un poste 18 de brasage à la vague au niveau duquel les plaquettes, portant les composants électroniques à braser, sont mises en contact avec au moins une vague d'un alliage de soudure.Referring to Figure 1, a wave soldering device according to the invention, comprises for the embodiment shown a device 10 for conveying circuits 12 (here for example printed circuit boards), a first station 14 for preheating the wafers, to a device 16 for processing the wafers 12 before brazing, by treatment of the latter with excited or unstable chemical species, then to a station 18 for wave soldering at the level of which the wafers, carrying the electronic components to be soldered, are brought into contact with at least one wave of a solder alloy.
Comme on le voit sur la figure 1, le dispositif de convoyage 10 comporte un ou plusieurs tapis de transfert, tel que 20, illustré en traits mixtes sur cette figure, sur lesquels sont disposés les plaquettes 12 de circuit imprimé.As can be seen in FIG. 1, the conveying device 10 comprises one or more transfer belts, such as 20, illustrated in phantom in this figure, on which the printed circuit boards 12 are arranged.
Chaque plaquette 12 est ici munie d'un ensemble de trous traversants dans lesquels s ' insèrent les pattes des composants électroniques, tel que 22 et 24, qu'il convient de braser. Comme cela est visible sur la figure 1, le tapisEach plate 12 is here provided with a set of through holes in which are inserted the tabs of the electronic components, such as 22 and 24, which should be soldered. As can be seen in Figure 1, the carpet
20 s'étend entre deux rouleaux de guidage, tels que 26, dont au moins l'un est moteur.20 extends between two guide rollers, such as 26, at least one of which is motor.
Les plaquettes 12, disposées sur le tapis 20 sont tout d'abord transférées du premier poste 14 de préchauffage au niveau duquel est disposé un dispositif de traitement thermique 28 approprié, puis vers le deuxième poste 16 de fluxage au niveau duquel les plaquettes subissent une opération de décontamination et de désoxydation par mise en contact des plaquettes avec des espèces gazeuses excitées ou instables. Les plaquettes ainsi fluxées sont ensuite mises en contact avec au moins une vague 30 d'alliage de soudure, au niveau du poste de soudure 18, laquelle vague 30 est obtenue par pompage d'un bain de soudure contenu dans un bac 32, au travers d'une buse 34. Les espèces gazeuses excitées ou instables, venant traiter les plaquettes 12 au niveau du poste de fluxage 16, sont ici obtenues en faisant passer un gaz initial approprié, par exemple un mélange gazeux réducteur contenant par exemple de l'azote et de l'hydrogène, à travers un dispositif, tel que 36, de formation d'espèces chimiques excitées ou instables, par passage du gaz initial dans une décharge électrique.The plates 12, disposed on the mat 20 are first transferred from the first preheating station 14 at which an appropriate heat treatment device 28 is disposed, then to the second fluxing station 16 at which the wafers undergo a decontamination and deoxidation operation by bringing the wafers into contact with excited or unstable gaseous species. The plates thus flowed are then brought into contact with at least one wave 30 of solder alloy, at the level of the soldering station 18, which wave 30 is obtained by pumping a solder bath contained in a tank 32, through of a nozzle 34. The excited or unstable gaseous species, coming to treat the wafers 12 at the fluxing station 16, are here obtained by passing an appropriate initial gas, for example a reducing gas mixture containing for example nitrogen and hydrogen, through a device, such as 36, for forming excited or unstable chemical species, by passing the initial gas through an electrical discharge.
Comme représenté sur la figure 2, chaque dispositif 36 de formation d'espèces chimiques excitées ou instables comporte pour le mode de réalisation représenté, une première électrode tubulaire 37, formée par exemple par une face interne d'un bloc 38 métallique, et dans laquelle est disposé concentriquement un ensemble formé d'un tube en matériau diélectrique 40 par exemple en céramique, sur la face interne duquel est déposée, par métallisation, une deuxième électrode 41 exagérément épaissie sur la figure 2, afin d'améliorer la clarté.As shown in FIG. 2, each device 36 for forming excited or unstable chemical species comprises, for the embodiment shown, a first tubular electrode 37, formed for example by an internal face of a metal block 38, and in which is concentrically arranged an assembly formed of a tube of dielectric material 40 for example ceramic, on the internal face of which is deposited, by metallization, a second electrode 41 excessively thickened in Figure 2, to improve clarity.
Le tube diélectrique 40 et la deuxième électrode 41 définissent, avec la première électrode 37, un passage tubulaire de gaz 42, et, intérieurement, un volume interne 44 dans lequel on fait circuler un fluide réfrigérant.The dielectric tube 40 and the second electrode 41 define, with the first electrode 37, a tubular gas passage 42, and, internally, an internal volume 44 in which a refrigerant is circulated.
Le bloc 38 comporte, diamétralement opposées, deux fentes longitudinales 46 et 48 formant respectivement l'entrée du gaz initial à exciter dans le passage 42 et la sortie de flux de gaz de traitement comportant les espèces gazeuses excitées ou instables.The block 38 comprises, diametrically opposite, two longitudinal slots 46 and 48 respectively forming the inlet of the initial gas to be excited in the passage 42 and the output of the treatment gas flow comprising the excited or unstable gaseous species.
Les fentes 46 et 48 s'étendent sur toute la longueur axiale de la cavité 42. Par ailleurs, le bloc 38 comporte en outre, avantageusement, à la périphérie de la première électrode 37 une pluralité de conduits, tels que 50, pour le passage d'un fluide réfrigérant, par exemple de l'eau.The slots 46 and 48 extend over the entire axial length of the cavity 42. Furthermore, the block 38 also advantageously comprises, at the periphery of the first electrode 37, a plurality of conduits, such as 50, for the passage a refrigerant, for example water.
On voit par ailleurs sur la figure 2 que la fente 46 d'entrée de gaz communique avec une chambre d'homogénéisation 52 formée dans une boîtier 54 accolé au bloc 38 et comportant une tubulure 56 d'amenée de gaz initial.It can also be seen in FIG. 2 that the gas inlet slot 46 communicates with a homogenization chamber 52 formed in a housing 54 attached to the block 38 and comprising a pipe 56 for supplying initial gas.
Le module est complété par un générateur électrique 58 à haute tension et haute fréquence destiné à engendrer une décharge dans le mélange gazeux circulant dans le passage de gaz 42 de manière à provoquer, une excitation des molécules gazeuses entrant dans sa constitution et générer ainsi en sortie 48, un mélange gazeux de traitement comportant des espèces chimiques excitées ou instables mais étant substantiellement dépourvu d'espèces électriquement chargées, qui viennent désoxyder et décontaminer la surface externe des plaquettes de circuit imprimé 20 (figure 1) . Comme il apparaîtra alors clairement à l'homme du métier, les plaquettes sont ici en situation de postdécharge.The module is completed by an electric generator 58 at high voltage and high frequency intended to generate a discharge in the gaseous mixture circulating in the gas passage 42 so as to cause, an excitation of the gaseous molecules entering into its constitution and thus generating at output 48, a treatment gas mixture comprising excited or unstable chemical species but being substantially free of electrically charged species, which deoxidize and decontaminate the external surface of the printed circuit boards 20 (FIG. 1). As will then clearly appear to those skilled in the art, the wafers are here in a post-discharge situation.
Ainsi, chaque dispositif 36 de formation d'espèces chimiques excitées ou instables génère, en sortie, un flux de gaz comportant des espèces chimiques émises selon une direction généralement perpendiculaire à la surface des plaquettes 12 à traiter.Thus, each device 36 for forming excited or unstable chemical species generates, at the outlet, a gas flow comprising chemical species emitted in a direction generally perpendicular to the surface of the wafers 12 to be treated.
Comme cela est visible sur les figures 3 et 4 , le flux de gaz comportant les espèces chimiques destinées à assurer le fluxage de la plaquette tend naturellement à s'évaser, de sorte que les particules situées en périphérie du flux tendent à se déplacer selon une direction sensiblement parallèle à la surface de la plaquette.As can be seen in Figures 3 and 4, the gas flow comprising the chemical species intended to ensure the fluxing of the wafer naturally tends to flare, so that the particles located in periphery of the flow tend to move in a direction substantially parallel to the surface of the wafer.
Comme cela a été mentionné précédemment, cette portion de flux présente une efficacité moindre pour le traitement des trous ménagés dans la plaquette pour le montage des composants.As mentioned previously, this portion of flux has a lower efficiency for the treatment of holes made in the plate for mounting the components.
Pour pallier cet inconvénient, et selon l'invention, on force les particules excitées à se propager sensiblement perpendiculairement à la plaquette de manière à venir s'engager dans les trous.To overcome this drawback, and according to the invention, the excited particles are forced to propagate substantially perpendicular to the wafer so as to come to engage in the holes.
Pour ce faire, on augmente localement la pression, sur chaque plaquette 12, du flux de gaz contenant les espèces chimiques. Plus préférentielle ent, dans la mesure où les particules incriminées se situent en périphérie du flux de traitement, la pression du flux de traitement est augmentée en périphérie du flux.To do this, the pressure is increased locally, on each plate 12, of the flow of gas containing the chemical species. More preferably, insofar as the particles in question are located at the periphery of the treatment flow, the pressure of the treatment flow is increased at the periphery of the flow.
Selon un premier mode de réalisation, visible sur la figure 3, on augmente la pression du flux de gaz activé en utilisant un jet de gaz auxiliaire d'entraînement (ne passant pas par la décharge électrique), par exemple de l'azote ou un gaz identique à celui utilisé pour générer les particules excitées, par exemple de l'azote mélangé avec de l'hydrogène et, le cas échéant, de la vapeur d'eau.According to a first embodiment, visible in FIG. 3, the pressure of the activated gas flow is increased by using a jet of auxiliary driving gas (not passing through the electrical discharge), for example nitrogen or a gas identical to that used to generate the excited particles, for example nitrogen mixed with hydrogen and, where appropriate, steam.
Comme cela est visible sur la figure 3, le jet de gaz d'entraînement est généré au moyen d'un dispositif d'entraînement 60, adapté pour projeter le gaz d'entraînement, prélevé à partir d'une enceinte 62, selon une direction sensiblement parallèle à l'axe des trous, c'est-à-dire perpendiculaire à la surface à traiter, comme représenté par les flèches F, et ce avec une vitesse relativement importante, par exemple comprise entre 10 et 100 m/s. Les moyens 60 pourront par exemple être constitués d'un couteau à effet venturi ou d'un amplificateur de débit.As can be seen in FIG. 3, the jet of drive gas is generated by means of a drive device 60, adapted to project the drive gas, taken from an enclosure 62, in a direction substantially parallel to the axis of the holes, that is to say perpendicular to the surface to be treated, as shown by the arrows F, and this with a relatively high speed, for example between 10 and 100 m / s. The means 60 could for example consist of a knife with a venturi effect or a flow amplifier.
Sous l'action de ce jet de gaz d'entraînement, les particules excitées ou instables sont dès lors forcées à se diriger parallèlement à l'axe des trous à traiter.Under the action of this jet of entrainment gas, the excited or unstable particles are therefore forced to move parallel to the axis of the holes to be treated.
On améliore ainsi considérablement la largeur de la zone traitée par le flux de particules excitées.The width of the area treated by the flow of excited particles is thus considerably improved.
Selon un autre mode de réalisation visible sur la figure 4, chaque plaquette, se situant au niveau du poste 16 de fluxage, dans une enceinte préférentiellement étanche, la pression du gaz de traitement sur la plaquette est augmentée au moyen d ' au moins un ventilateur 64 tourné vers la plaquette et disposé au niveau de la périphérie du flux de gaz de manière à forcer, dans cette zone, le flux de gaz de traitement à se diriger dans une direction sensiblement perpendiculaire à la plaquette.According to another embodiment visible in FIG. 4, each plate, being located at the level of the fluxing station 16, in a preferably sealed enclosure, the pressure of the treatment gas on the plate is increased by means of at least one fan. 64 turned towards the wafer and disposed at the periphery of the gas flow so as to force, in this zone, the flow of treatment gas to move in a direction substantially perpendicular to the wafer.
On conçoit que, dans ce mode de réalisation, le gaz d'entraînement est prélevé à partir du gaz de traitement présent dans l'enceinte.It is understood that, in this embodiment, the entrainment gas is taken from the treatment gas present in the enclosure.
Comme dans le mode de réalisation décrit précédemment en référence à la figure 3, il est ainsi possible d'augmenter considérablement, à l'aide de ce dispositif d'entraînement, la surface traitée par le flux de gaz contenant les espèces excitées ou instables.As in the embodiment described above with reference to FIG. 3, it is thus possible to considerably increase, using this drive device, the surface treated by the gas flow containing the excited or unstable species.
Quoique la présente invention ait été décrite en relation avec des modes de réalisation particuliers, elle ne s'en trouve pas limitée pour autant mais est au contraire susceptible de modifications et de variantes qui apparaîtront à l'homme de l'art dans le cadre des revendications ci-après.Although the present invention has been described in relation to particular embodiments, it is not limited thereby, but is on the contrary subject to modifications and variants which will appear to those skilled in the art in the context of claims below.
Ainsi, si l'invention a été tout particulièrement exemplifiée dans ce qui précède dans le cas du brasage à la vague de composants sur circuits électroniques, on comprend qu'elle s'applique beaucoup plus largement à bien d'autres traitements de surface, qu'il s'agisse de traitements d surfaces mis en oeuvre dans la fabrication de circuits imprimés, mono ou multicouches (opérations de décapage, nettoyage, ébavurage des trous de connexion- « desmearing »- ou encore fluxage avant étamage ou autre dépôt de couches métalliques) et bien sûr dans d'autres industries mettant en oeuvre d'autres types de surfaces métalliques. Thus, if the invention has been particularly exemplified in the above in the case of wave soldering of components on electronic circuits, it is understood that it applies much more widely to many other surface treatments, whether surface treatments used in the manufacture of printed circuits, single or multi-layer (pickling operations, cleaning, deburring of connection holes - "desmearing" - or even fluxing before tinning or other deposition of metallic layers) and of course in other industries using other types of metallic surfaces.

Claims

REVENDICATIONS
1. Procédé de traitement de surface par voie sèche d'au moins une portion de surface métallique, selon lequel la portion est traitée à une pression voisine de la pression atmosphérique par un flux de gaz de traitement comprenant des espèces excitées ou instables, caractérisé en ce que 1 ' on augmente localement la pression du gaz de traitement sur la portion de surface métallique de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à ladite surface.1. A method of surface treatment by dry process of at least a portion of metal surface, according to which the portion is treated at a pressure close to atmospheric pressure by a flow of treatment gas comprising excited or unstable species, characterized in that one increases locally the pressure of the treatment gas on the metal surface portion so as to force the chemical species to move in a direction substantially perpendicular to said surface.
2. Procédé selon la revendication 1, caractérisé en ce que les espèces chimiques excitées ou instables sont obtenues par passage d'un gaz initial dans une décharge électrique.2. Method according to claim 1, characterized in that the excited or unstable chemical species are obtained by passing an initial gas through an electric discharge.
3. Procédé selon la revendication 1 ou 2 , caractérisé en ce que ledit gaz de traitement est substantiellement dépourvu d'espèces électriquement chargées. 3. Method according to claim 1 or 2, characterized in that said treatment gas is substantially free of electrically charged species.
4. Procédé selon la revendication 3 caractérisé en ce que ledit gaz de traitement est obtenu à partir d'un mélange gazeux primaire et le cas échéant d'un mélange gazeux adjacent, ledit mélange gazeux primaire étant obtenu à la sortie de gaz d'au moins un appareil de formation d'espèces gazeuses excitées ou instables, dans lequel a été transformé un mélange gazeux initial comprenant un gaz inerte et/ou un gaz réducteur et/ou un gaz oxydant, ledit mélange adjacent n'ayant pas transité par le dit appareil. 4. Method according to claim 3 characterized in that said treatment gas is obtained from a primary gas mixture and if necessary from an adjacent gas mixture, said primary gas mixture being obtained at the outlet of gas from minus an apparatus for forming excited or unstable gaseous species, in which an initial gas mixture comprising an inert gas and / or a reducing gas and / or an oxidizing gas has been transformed, said adjacent mixture having not passed through said apparatus.
5. Procédé selon l'une des revendications 1 à 4, caractérisé en ce que le flux de gaz de traitement étant émis en direction de ladite portion de surface selon une direction généralement perpendiculaire à celle-ci, et comportant, en périphérie, des particules excitées ou instables animées d'un mouvement selon une direction sensiblement tangente à ladite portion de surface, la pression du gaz de traitement sur ladite portion de surface est augmentée en périphérie dudit flux.5. Method according to one of claims 1 to 4, characterized in that the flow of treatment gas being emitted in the direction of said surface portion in a direction generally perpendicular thereto, and comprising, at the periphery, particles excited or unstable animated by a movement in a direction substantially tangent to said surface portion, the pressure of the treatment gas on said surface portion is increased at the periphery of said flow.
6. Procédé selon l'une des revendications 1 à 5, caractérisé en ce que la pression du gaz de traitement sur ladite portion de surface est augmentée au moyen d'au moins un flux de gaz d'entraînement injecté perpendiculairement à ladite portion de surface.6. Method according to one of claims 1 to 5, characterized in that the pressure of the treatment gas on said surface portion is increased by means of at least one flow of entrainment gas injected perpendicular to said surface portion .
7. Procédé selon la revendication 6, caractérisé en ce que le gaz d'entraînement comporte de l'azote. 7. Method according to claim 6, characterized in that the entrainment gas comprises nitrogen.
8. Procédé selon l'une des revendications 1 à 5, caractérisé en ce que ladite portion de surface étant disposée dans une chambre de traitement, la pression du gaz de traitement sur ladite portion de surface est augmentée au moyen d'au moins un ventilateur tourné vers ladite surface de manière à forcer le flux de gaz de traitement à venir frapper ladite portion de surface selon une direction sensiblement perpendiculaire à cette dernière.8. Method according to one of claims 1 to 5, characterized in that said surface portion being disposed in a treatment chamber, the pressure of the treatment gas on said surface portion is increased by means of at least one fan turned towards said surface so as to force the flow of treatment gas to strike said surface portion in a direction substantially perpendicular to the latter.
9. Procédé selon l'une des revendications 1 à 8, caractérisé en ce que ladite portion de surface métallique est présente sur une plaquette de circuits imprimés, et en ce que ledit traitement de surface réalise l'une ou plusieurs des fonctions suivantes sur ladite surface : nettoyage, dégraissage, activation de surface, ébavurage, fluxage avant brasage ou étamage.9. Method according to one of claims 1 to 8, characterized in that said metal surface portion is present on a printed circuit board, and in that said surface treatment performs one or more of the following functions on said surface: cleaning, degreasing, surface activation, deburring, fluxing before soldering or tinning.
10. Procédé de brasage à la vague de composants électroniques (22,24) sur circuit électronique au cours duquel : on place les composants (22,24) sur des emplacements de connexion ménagés sur le circuit, on effectue une opération de fluxage du circuit (12) par traitement de cette dernière, à une pression voisine de la pression atmosphérique, au moyen d'un flux de gaz de traitement, en utilisant le procédé de traitement de surface selon l'une quelconque des revendications 1 à 9 ; et - on met le circuit (12) portant les composants (22,24) en contact avec une vague (30) d'un alliage de soudure .10. A method of wave soldering electronic components (22,24) on an electronic circuit during which: the components (22,24) are placed on connection locations provided on the circuit, a circuit fluxing operation is carried out (12) by treatment of the latter, at a pressure close to atmospheric pressure, by means of a flow of treatment gas, using the surface treatment method according to any one of claims 1 to 9; and - The circuit (12) carrying the components (22,24) is brought into contact with a wave (30) of a solder alloy.
11. Procédé selon la revendication 10, caractérisé en ce que le flux de gaz de traitement étant émis en direction du circuit (12) selon une direction généralement perpendiculaire à celle-ci, et comportant, en périphérie, des particules excitées ou instables animées d'un mouvement selon une direction sensiblement tangente à la surface du circuit (12) , la pression du flux de gaz de traitement sur le circuit (12) est augmentée en périphérie dudit flux.11. Method according to claim 10, characterized in that the flow of treatment gas being emitted in the direction of the circuit (12) in a direction generally perpendicular thereto, and comprising, at the periphery, excited or unstable particles animated by 'A movement in a direction substantially tangent to the surface of the circuit (12), the pressure of the flow of process gas on the circuit (12) is increased at the periphery of said flow.
12. Procédé selon l'une des revendications 10 ou 11, caractérisé en ce que la pression du gaz de traitement sur le circuit est augmentée au moyen d'au moins un flux de gaz d'entraînement injecté perpendiculairement au circuit.12. Method according to one of claims 10 or 11, characterized in that the pressure of the treatment gas on the circuit is increased by means of at least one flow of drive gas injected perpendicular to the circuit.
13. Procédé selon la revendication 12, caractérisé en ce que le gaz d'entraînement comporte de l'azote. 13. Method according to claim 12, characterized in that the entrainment gas comprises nitrogen.
14. Procédé selon l'une des revendications 10 ou14. Method according to one of claims 10 or
11, caractérisé en ce qu'au cours de l'étape de fluxage, le circuit étant disposé dans une chambre de traitement, la pression du gaz de traitement sur le circuit est augmentée au moyen d'au moins un ventilateur (64) tourné vers le circuit de manière à forcer le flux de gaz de traitement à venir frapper le circuit (12) selon une direction sensiblement perpendiculaire à ce dernier.11, characterized in that during the fluxing step, the circuit being placed in a treatment chamber, the pressure of the treatment gas on the circuit is increased by means of at least one fan (64) facing the circuit so as to force the flow of treatment gas to strike the circuit (12) in a direction substantially perpendicular to the latter.
15. Procédé selon l'une quelconque des revendications 10 à 14, caractérisé en ce que les espèces chimiques excitées ou instables sont obtenues par passage d'un gaz initial dans une décharge électrique.15. Method according to any one of claims 10 to 14, characterized in that the excited or unstable chemical species are obtained by passing an initial gas through an electric discharge.
16. Procédé selon l'une quelconque des revendications 10 à 15, caractérisé en ce que le gaz de traitement comportant les espèces chimiques excitées ou instables est produit à partir d'un mélange gazeux réducteur comportant de l'azote et de l'hydrogène. 16. Method according to any one of claims 10 to 15, characterized in that the treatment gas comprising the excited or unstable chemical species is produced from a reducing gas mixture comprising nitrogen and hydrogen.
17. Procédé selon l'une quelconque des revendications 10 à 16, caractérisé en ce que ledit gaz de traitement est substantiellement dépourvu d'espèces électriquement chargées. 17. Method according to any one of claims 10 to 16, characterized in that said treatment gas is substantially free of electrically charged species.
18. Procédé selon la revendication 17 caractérisé en ce que ledit gaz de traitement est obtenu à partir d'un mélange gazeux primaire et le cas échéant d'un mélange gazeux adjacent, ledit mélange gazeux primaire étant obtenu à la sortie de gaz d'au moins un appareil de formation d'espèces gazeuses excitées ou instables, dans lequel a été transformé un mélange gazeux initial comprenant un gaz inerte et/ou un gaz réducteur et/ou un gaz oxydant, ledit mélange adjacent n'ayant pas transité par le dit appareil. 18. The method of claim 17 characterized in that said treatment gas is obtained from a primary gas mixture and optionally from an adjacent gas mixture, said primary gas mixture being obtained at the outlet of gas from minus an apparatus for forming excited or unstable gaseous species, in which an initial gas mixture comprising an inert gas and / or a reducing gas and / or an oxidizing gas has been transformed, said adjacent mixture having not passed through said apparatus.
19. Procédé selon l'une quelconque des revendications 10 à 18, caractérisé en ce que le circuit électronique traité est une plaquette de circuits imprimés.19. Method according to any one of claims 10 to 18, characterized in that the electronic circuit treated is a printed circuit board.
20. Appareil de traitement d'au moins une portion de surface métallique par voie sèche, pour la mise en oeuvre d'un procédé selon l'une quelconque des revendications 1 à 9, caractérisé en ce qu'il comporte une source de gaz de traitement comportant des espèces chimiques excitées ou instables, un dispositif de convoyage de pièces comportant ladite au moins une portion de surface métallique, permettant d'amener les pièces en contact avec un flux de gaz de traitement, caractérisé en ce qu'il comporte des moyens pour augmenter localement la pression du gaz de traitement sur chaque pièce, de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à cette dernière.20. Apparatus for treating at least a portion of metal surface by the dry route, for implementing a method according to any one of claims 1 to 9, characterized in that it comprises a source of treatment comprising excited or unstable chemical species, a device for conveying parts comprising said at least one portion of metal surface, making it possible to bring the parts into contact with a flow of treatment gas, characterized in that it comprises means to locally increase the pressure of the treatment gas on each part, so as to force the chemical species to move in a direction substantially perpendicular to the latter.
21. Appareil de brasage à la vague de composants électroniques (22,24) sur une plaquette de circuit imprimé, pour la mise en oeuvre d'un procédé selon l'une quelconque des revendications 10 à 19, caractérisé en ce qu'il comporte un dispositif (10) de convoyage de plaquettes à travers au moins un dispositif (36) de fluxage des plaquettes, par traitement de ces dernières au moyen d'un flux de gaz de traitement comportant des espèces chimiques excitées ou instables, lesdites plaquettes (12) portant sur au moins une de leur face les composants (22,24) à braser, sur des emplacements de connexion de ces derniers, puis à travers un bac (32) contenant un alliage de soudure en vue du brasage des composants, et en ce que le ou chaque dispositif (36) de fluxage comporte des moyens (60, 62; 64) pour augmenter localement la pression du gaz de traitement sur chaque plaquette (12) , de manière à forcer les espèces chimiques à se déplacer selon une direction sensiblement perpendiculaire à cette dernière. 21. Apparatus for wave soldering of electronic components (22,24) on a printed circuit board, for implementing a method according to any one of claims 10 to 19, characterized in that it comprises a device (10) for conveying wafers through at least one device (36) for fluxing the wafers, by treatment of the latter by means of a flow of treatment gas comprising excited or unstable chemical species, said plates (12) carrying on at least one of their faces the components (22,24) to be brazed, on connection locations of the latter, then through a tank (32) containing a solder alloy for the soldering of components, and in that the or each fluxing device (36) comprises means (60, 62; 64) for locally increasing the pressure of the treatment gas on each wafer (12), so as to force the chemical species to move in a direction substantially perpendicular to the latter.
EP99914612A 1998-05-04 1999-04-19 Method and apparatus for treating metal surfaces by dry process Withdrawn EP0996770A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9805603A FR2778190B1 (en) 1998-05-04 1998-05-04 METHOD AND APPARATUS FOR TREATING METAL SURFACES BY DRY WAY
FR9805603 1998-05-04
PCT/FR1999/000916 WO1999057334A1 (en) 1998-05-04 1999-04-19 Method and apparatus for treating metal surfaces by dry process

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JP (1) JP2002509583A (en)
KR (1) KR20010015531A (en)
CN (1) CN1266463A (en)
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CA (1) CA2293610A1 (en)
FR (1) FR2778190B1 (en)
ID (1) ID24519A (en)
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FR2820717A1 (en) * 2001-02-15 2002-08-16 Air Liquide Method, for avoiding splitting or rupturing of electronic components during mounting on circuit boards using soldering, has components kept in packaging within container with controlled humidity level
JP4522753B2 (en) 2004-06-11 2010-08-11 株式会社エヌ・ティ・ティ・ドコモ Frequency selection device, radio communication system, and radio control channel setting method

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GB8827933D0 (en) * 1988-11-30 1989-01-05 Plessey Co Plc Improvements relating to soldering processes
DE4032328A1 (en) * 1989-11-06 1991-09-19 Wls Karl Heinz Grasmann Weichl METHOD AND DEVICE FOR PROCESSING JOINT PARTNERS TO BE SOLDERED
GB2274286B (en) * 1993-01-13 1996-11-06 Singapore Asahi Chemical & Solder Ind Pte Ltd Method of and apparatus for preparing an electric circuit board for a flow or wave soldering process
FR2713670B1 (en) * 1993-12-15 1996-01-12 Air Liquide Method and device for treating metallic surfaces by dry process.
FR2713528B1 (en) * 1993-12-15 1996-01-12 Air Liquide Method and device for dry fluxing of metal surfaces before brazing or tinning.
FR2735053B1 (en) * 1995-06-09 1997-07-25 Air Liquide METHOD AND DEVICE FOR WAVE BRAZING INCORPORATING DRY FLUXING OPERATION
FR2735054B1 (en) * 1995-06-09 1997-07-25 Air Liquide PROCESS FOR FLUXING BY DRY WAY OF METAL SURFACES BEFORE BRAZING OR TINNING USING AN ATMOSPHERE CONTAINING WATER VAPOR
CH692446A5 (en) * 1996-04-15 2002-06-28 Esec Sa A process for the production of workpieces and parts thereof

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KR20010015531A (en) 2001-02-26
CA2293610A1 (en) 1999-11-11
ID24519A (en) 2000-07-20
JP2002509583A (en) 2002-03-26
WO1999057334A1 (en) 1999-11-11
CN1266463A (en) 2000-09-13
FR2778190A1 (en) 1999-11-05
FR2778190B1 (en) 2000-06-02
TW548346B (en) 2003-08-21

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