FR2549290A1 - Conducting ink for producing contacts by serigraphy on semiconducting silicon, method of producing a contact by serigraphy using such an ink and photovoltaic cell provided with such a contact - Google Patents

Conducting ink for producing contacts by serigraphy on semiconducting silicon, method of producing a contact by serigraphy using such an ink and photovoltaic cell provided with such a contact Download PDF

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FR2549290A1
FR2549290A1 FR8311718A FR8311718A FR2549290A1 FR 2549290 A1 FR2549290 A1 FR 2549290A1 FR 8311718 A FR8311718 A FR 8311718A FR 8311718 A FR8311718 A FR 8311718A FR 2549290 A1 FR2549290 A1 FR 2549290A1
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ink
silicon
weight
powder
contact
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FR2549290B1 (en
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Pierre Lebrun
Jerome Donon
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Photowatt International SA
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Photowatt International SA
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    • H01L23/4827—Materials
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    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Abstract

The conducting ink produces a contact by serigraphy on a surface of silicon with a semiconducting junction. The ink is formed after firing a conducting deposit consisting of its permanent constituents. The ink comprises: - an active permanent material in powdered form, mostly metallic, the grains of which will conduct electricity through the deposit, - a passive permanent material consisting of grains of glass which are to provide for the adhesion of the deposit on the silicon, the coefficient of expansion of glass being close to that of silicon, - a temporary organic binder making the ink thixotropic and removable by pyrolysis without charring, - a solvent removable by drying. The active permanent material mainly contains nickel powder with the addition of a smaller amount of boron powder. Application to photovoltaic cells.

Description

Encre conductrice pour prise de contact par sérigraphie sur du silicium semi-conducteur, procédé de réalisation d'un contact par sérigraphie à l'aide d'une telle encre, et cellule photovoltaique munie d'un tel contact
La présente invention concerne une encre conductrice pour prise de contact par sérigraphie sur une surface de silicium à jonction semi-conductrice, cette encre étant destinée à former après cuisson un dépôt conducteur constitué par ses matériaux permanents, et comportant - un matériau permanent actif en poudre, en majeure partie métallique, dont les grains conduiront l'électricité au sein du dépôt, - un matériau permanent passif constitué de grains de verre et devant assurer l'adhérence du dépôt sur le silicium, le coefficient de dilatation du verre étant voisin de celui du silicium, - un liant temporaire organique propre à rendre l'encre thixotropique et pouvant s'éliminer par pyrolyse sans charbonner, - et un solvant éliminable par séchage,
Elle s'applique plus particulièrement à la connexion électrique d'éléments photovoltaiques de modules de cellules solaires.Conductive ink for making contact by screen printing on semiconductor silicon, method for making a contact by screen printing using such an ink, and photovoltaic cell provided with such a contact
The present invention relates to a conductive ink for making contact by screen printing on a silicon surface with semiconductor junction, this ink being intended to form, after firing, a conductive deposit consisting of its permanent materials, and comprising - a permanent active powder material , mainly metallic, the grains of which will conduct electricity within the deposit, - a passive permanent material made up of glass grains and having to ensure the adhesion of the deposit to silicon, the coefficient of expansion of the glass being close to that silicon, - a temporary organic binder capable of rendering the ink thixotropic and capable of being eliminated by pyrolysis without carbon, - and a solvent which can be removed by drying,
It applies more particularly to the electrical connection of photovoltaic elements of solar cell modules.

Un tel module se présente classiquement sous la forme d'un panneau dont la face avant est exposée au soleil. En partant de cette face il comporte successivement - une paroi avant transparente au rayonnement solaire, - des cellules photovoltaiques pouvant prendre par exemple la forme de disques de silicium qui sont disposés derrière cette paroi pour recevoir ce rayonnement et dans lesquels on a créé une jonction semi-conductrice, une grille conductrice en face avant et un contact arrière étant formés sur chaque cellule pour collecter le courant électrique produit, des connexions entre grilles conductrices et contacts arrières de cellules voisines assurant la connexion des cellules en série, et parfois en parallèle, - et une couche protectrice arrière. Such a module is conventionally in the form of a panel whose front face is exposed to the sun. Starting from this face it successively comprises - a front wall transparent to solar radiation, - photovoltaic cells which can take, for example, the form of silicon disks which are arranged behind this wall to receive this radiation and in which a semi-junction has been created -conductive, a conductive grid on the front face and a rear contact being formed on each cell to collect the electric current produced, connections between conductive grids and rear contacts of neighboring cells ensuring the connection of the cells in series, and sometimes in parallel, - and a rear protective layer.

Ces cellules sont fabriquées, à partir de disques de silicium semi-conducteur d'un type de conductivité déterminé, en général P, par diffusion d'un élément de dopage du type opposé, en général N, de manière à réaliser une inversion du type de conductivité du semi-conducteur sur une petite fraction de ltép tsseur du disque. On crée ainsi une jonction
"#YU# semi-conductrice interne. Cette diffusion se fait à une température, qui est de l'ordre de 8000 à 1100 C, et pendant une durée qui sont déterminées avec soin de manière à obtenir une bonne efficacité de conversion photovoltaique. These cells are made from semiconductor silicon disks of a determined type of conductivity, in general P, by diffusion of a doping element of the opposite type, in general N, so as to produce an inversion of the type of conductivity of the semiconductor on a small fraction of the ltép tsseur of the disc. We thus create a junction
"# YU # internal semiconductor. This diffusion takes place at a temperature, which is of the order of 8000 to 1100 ° C., and for a duration which are carefully determined so as to obtain good photovoltaic conversion efficiency.

Pour la réalisation des contacts permettant la collecte du courant sur les cellules, c'est-à-dire de la grille conductrice avant et du contact arrière, il est connu d'utiliser des encres conductrices mises en oeuvre par sérigraphie. For making the contacts allowing the current to be collected on the cells, that is to say the front conductive grid and the rear contact, it is known to use conductive inks used by screen printing.

Les encres sérigraphiables, servant à réaliser des couches épaisses conductrices, étaient constituées principalement - d'un matériau actif, généralement de l'argent finement divisé, qui procure la conductibilité électrique, - d'un matériau passif, tel qu'un verre de scellement, dont le rôle consiste lors de la cuisson de l'encre à rendre le contact conducteur solidaire de la surface du silicium, - d'un liant temporaire organique à propriétés thixotropiques, approprié à la sérigraphie et pouvant s'éliminer par pyrolyse sans laisser de résidu carboné, - et dlun solvant éliminable par séchage. The screen-printing inks used to make thick conductive layers consisted mainly of - an active material, generally finely divided silver, which provides electrical conductivity, - a passive material, such as a sealing glass , whose role consists in curing the ink to make the conductive contact integral with the silicon surface, - a temporary organic binder with thixotropic properties, suitable for screen printing and which can be eliminated by pyrolysis without leaving any carbon residue, - and a solvent which can be removed by drying.

Le matériau passif - verre de scellement - doit présenter une température de scellement faible, de l'ordre de 6000C, afin de ne pas modifier les propriétés électriques et d'éviter la diffusion d'impuretés pouvant notamment être constituées par le métal du matériau actif. The passive material - sealing glass - must have a low sealing temperature, of the order of 6000C, so as not to modify the electrical properties and to avoid the diffusion of impurities which may in particular be formed by the metal of the active material. .

Pour le liant temporaire et le solvant, on utilise des matières connues, telles que l'éthyl-cellulose et le terpinéol ou l'acétate de butylcarbitol. Le liant s'élimine lors du chauffage aux températures de cuisson de l'encre sans laisser de résidu. Known materials such as ethyl cellulose and terpineol or butylcarbitol acetate are used for the temporary binder and the solvent. The binder is removed when heating to the ink curing temperatures without leaving a residue.

Dans 11 encre sérigraphiable, avant cuisson, le liant temporaire et les solvants peuvent représenter 10 à 35% en poids par rapport au total des matériaux actif et passif, bien que ces proportions puissent être adaptées à volonté pour modifier les propriétés rhéologiques de l'encre. In 11 screen-printing ink, before curing, the temporary binder and the solvents can represent 10 to 35% by weight relative to the total of the active and passive materials, although these proportions can be adapted at will to modify the rheological properties of the ink. .

Dans le matériau obtenu après cuisson, loes matériaux actif et passif peuvent représenter respectivement environ 90% et 10% en poids. In the material obtained after baking, the active and passive materials can represent approximately 90% and 10% by weight respectively.

Les encres conductrices connues présentent divers inconvénients. Known conductive inks have various drawbacks.

Celles à base d'argent sont chères; les cellules réalisées avec ces encres n'ont pas un facteur de forme (forme de la courbe représentant l'intensité en fonction de la tension) excellent. Celles à base de cuivre créent un danger important d'altération des propriétés semi-conductrices du silicium par diffusion dans celui-ci d'atomes de cuivre. Celles à base de nickel dégradent les caractéristiques de la jonction après cuisson, et leur matériau actif présente une résistivité propre supérieure à celle d'un matériau à l'argent.Silver-based ones are expensive; the cells produced with these inks do not have an excellent form factor (shape of the curve representing the intensity as a function of the voltage). Those based on copper create a significant danger of deterioration of the semiconductor properties of silicon by diffusion in it of copper atoms. Those based on nickel degrade the characteristics of the junction after firing, and their active material has a specific resistivity greater than that of a silver material.

Il a été proposé dans la demande de brevet n0 81 20723 du 5 novembre 1981 de la demanderesse d'additionner dans l'encre la poudre de nickel d'une poudre d'étain, en proportion en poids de 8 à 35% d'étain, la proportion de nickel restant supérieure à 60%, et après formation d'une couche conductrice à base de cette encre, de former une couche supérieure plus conductrice à partir d'une encre à base de cuivre, pour compenser la résistivité électrique relativement élevée du nickel. It was proposed in patent application No. 81 20723 of November 5, 1981 of the applicant to add in the ink the nickel powder of a tin powder, in proportion by weight of 8 to 35% tin , the proportion of nickel remaining greater than 60%, and after forming a conductive layer based on this ink, to form an upper more conductive layer from a copper-based ink, to compensate for the relatively high electrical resistivity nickel.

Un tel contact peut convenir pour la face arrière de cellules solaires au silicium, mais des problèmes de centrage lui font préférer pour la face avant un contact à l'argent classique. Such a contact may be suitable for the rear face of silicon solar cells, but problems of centering make it prefer for the front face a contact with conventional silver.

Par ailleurs, sa réalisation est plus complexe, puisqu'elle nécessite deux sérigraphies et deux cuissons successives. Furthermore, its production is more complex, since it requires two serigraphs and two successive firings.

La présente invention a donc pour but de procurer une encre conductrice sérigraphiable peu coûteuse, ne nécessitant pas une température de cuisson élevée, permettant de former des contacts bien adhérents sur le silicium et d'obtenir des cellules photovoltaiques de facteur de forme amélioré par rapport aux cellules connues, et présentant un rendement de conversion de l'énergie lumineuse égal ou supérieur à celui des cellules connues obtenues à l'aide d'encres sérigraphiables à l'argent. The present invention therefore aims to provide an inexpensive screen printing conductive ink, not requiring a high baking temperature, allowing to form well adherent contacts on silicon and to obtain photovoltaic cells with improved form factor compared to known cells, and having a conversion efficiency of light energy equal to or greater than that of known cells obtained using screen-printing inks with silver.

L'encre conductrice selon l'invention est caractérisée en ce que son matériau permanent actif contient essentiellement de la poudre de nickel, additionnée d'une moindre quantité de poudre de bore. The conductive ink according to the invention is characterized in that its permanent active material contains essentially nickel powder, added with a smaller amount of boron powder.

Bien que l'invention ne soit pas liée à une explication théorique des phénomènes, on peut penser que l'amélioration obtenue avec l'encre sérigraphiable selon 11 invention résulte d'une part de ce que la résistance de contact proprement dite entre nickel et silicium doit être plus faible que celle entre argent et silicium. Par ailleurs, le bore s'oxyde préférentiellement au nickel, et doit donc éviter une oxydation initiale de ce dernier, et l'anhydride borique plus fusible favorise le frittage du nickel, en dissolvant les petites quantités d'oxyde de nickel qui peuvent se former, ce qui assure une bonne cohésion du contact. Although the invention is not linked to a theoretical explanation of the phenomena, one can think that the improvement obtained with the screen-printing ink according to the invention results on the one hand from the fact that the contact resistance proper between nickel and silicon must be lower than that between silver and silicon. In addition, the boron oxidizes preferentially to nickel, and must therefore avoid an initial oxidation of the latter, and the more fusible boric anhydride promotes the sintering of nickel, by dissolving the small quantities of nickel oxide which can form. , which ensures good contact cohesion.

Il a d'ailleurs été vérifié que si l'on essaie de constituer un contact à l'aide de poudre de nickel seul mélangée à la poudre de verre, il ne se produit pas de frittage. It has moreover been verified that if an attempt is made to make a contact using nickel powder alone mixed with the glass powder, no sintering occurs.

L'encre conductrice selon l'invention répond en outre de préférence à au moins l'une des caractéristiques suivantes
- Son matériau permanent actif contient 80 à 97% en poids de poudre de nickel et 3 à 20% en poids de poudre de bore.The conductive ink according to the invention also preferably meets at least one of the following characteristics
- Its permanent active material contains 80 to 97% by weight of nickel powder and 3 to 20% by weight of boron powder.

- Son matériau permanent actif contient environ 89% en poids de poudre de nickel et 11% de poudre de bore. - Its permanent active material contains approximately 89% by weight of nickel powder and 11% of boron powder.

- Sa poudre de nickel est de granulométrie inférieure à 20 microns. - Its nickel powder has a particle size less than 20 microns.

- Elle contient de 3 à 25S en poids de poudre de verre. - It contains 3 to 25% by weight of glass powder.

- Le verre est un borosilicate de plomb en grains de dimension inférieure à 20 microns. - The glass is a lead borosilicate in grains of dimension less than 20 microns.

- Elle contient 75% en poids d'une partie minérale à 80% en poids de poudre de nickel, 10% en poids de poudre de verre et 10% en poids de poudre de bore, et 25% en poids de produits organiques comprenant au moins un solvant et un liant, en proportions telles que la viscosité de l'encre varie de 2,65.10 à 3,2.103 m Pa.s environ pour un taux de -1 cisaillement compris entre 20 et 1300 s
L'invention s'étend en outre à un procédé de réalisation d'un contact par sérigraphie sur un disque de silicium semi-conducteur, ce procédé comportant a/ un dépot par sérigraphie sur le silicium d'une encre conductrice telle que définie ci-dessus b/ un chauffage modéré pour évaporer le solvant c/ une pyrolyse du liant d/ un frittage de l'encre en présence d'air assurant son adhésion sur le silicium e/ un recuit sous atmosphère réductrice, caractérisé en ce que le frittage de l'encre est assuré par chauffage à une température au plus égale à 6000C pendant environ 5 minutes. - It contains 75% by weight of a mineral part at 80% by weight of nickel powder, 10% by weight of glass powder and 10% by weight of boron powder, and 25% by weight of organic products comprising minus a solvent and a binder, in proportions such that the viscosity of the ink varies from 2.65.10 to 3.2.103 m Pa.s approximately for a rate of -1 shear of between 20 and 1300 s
The invention further extends to a method of producing a contact by screen printing on a semiconductor silicon disc, this method comprising a / a deposit by screen printing on the silicon of a conductive ink as defined above. above b / moderate heating to evaporate the solvent c / pyrolysis of the binder d / sintering of the ink in the presence of air ensuring its adhesion to the silicon e / annealing under a reducing atmosphere, characterized in that the sintering of the ink is ensured by heating to a temperature at most equal to 6000C for approximately 5 minutes.

De préférence, on dépose sur la face avant du disque de silicium l'encre conductrice au nickel et au bore, et lorsque l'on désire conserver sur la face arrière un contact à l'argent, on effectue chauffage, pyrolyse et frittage séparément sur les faces avant et arrière, le frittage sur la face avant ayant lieu à 5900C pendant environ 5 minutes, et celui sur la face arrière à au moins 6500C pendant environ 10 minutes. Preferably, the conductive ink with nickel and boron is deposited on the front face of the silicon disc, and when it is desired to maintain a silver contact on the rear face, heating, pyrolysis and sintering are carried out separately on the front and rear faces, the sintering on the front face taking place at 5900C for approximately 5 minutes, and that on the rear face at least 6500C for approximately 10 minutes.

L'invention s'étend encore à une cellule photovoltalque à disque de silicium à jonction semi-conductice, caractérisée en ce qu'elle comporte au moins en face avant un contact obtenu par sérigraphie, puis chauffage, pyrolyse et frittage d'une encre contenant comme matériau permanent actif essentiellement de la poudre de nickel additionnée d'une moindre quantité de poudre de bore. The invention further extends to a silicon disc photovoltaic cell with semiconductor junction, characterized in that it comprises at least on the front face a contact obtained by screen printing, then heating, pyrolysis and sintering of an ink containing as a permanent active material essentially nickel powder added with a smaller amount of boron powder.

Il est décrit ci-après, à titre d'exemple et en référence à la figure unique du dessin annexé, un procédé de réalisation d'un contact au nickel et au bore sur la face avant d'une cellule au silicium, et les propriétés d'une cellule de 100 mm de diamètre comportant ce contact et un contact à l'argent sur sa face arrière. It is described below, by way of example and with reference to the single figure of the accompanying drawing, a process for producing a nickel and boron contact on the front face of a silicon cell, and the properties a 100 mm diameter cell comprising this contact and a silver contact on its rear face.

On utilise une poudre de nickel de dimension inférieure à 20 microns, et de grosseur de grain moyenne environ 5 microns, et une poudre de verre au borosilicate de plomb, de granulométrie également inférieure à 20 microns, de composition pondérale 75% d'oxyde de plomb, 10% d'anhydride borique, 10% de silice, additionnés de 5% d'alumine. Les proportions pondérales respectives des constituants du matériau minéral de l'encre sont 80% de poudre de nickel, 10% de poudre de bore et 10% de poudre de verre. A nickel powder with a size of less than 20 microns and an average grain size of about 5 microns is used, and a glass powder with lead borosilicate, of particle size also less than 20 microns, with a weight composition of 75% oxide lead, 10% boric anhydride, 10% silica, added with 5% alumina. The respective weight proportions of the constituents of the mineral material of the ink are 80% nickel powder, 10% boron powder and 10% glass powder.

On ajoute à 3 parties de ce matériau minéral une partie d'une solution d'éthylcellulose dans le terpinéol. Les proportions ainsi choisies donnent une encre thixotropique dont la viscosité varie en fonction du taux de cisaillement selon la relation représentée en coordonnées logarithmiques en figure 1 du dessin. Sa viscosité d'environ m m Pa.s pour un taux de cisaillement de 20 s1, décroît jusqu'à 3,2.103 pour un taux de cisaillement D 1 de 1,3.103. One part of a solution of ethylcellulose in terpineol is added to 3 parts of this mineral material. The proportions thus chosen give a thixotropic ink whose viscosity varies as a function of the shear rate according to the relationship represented in logarithmic coordinates in FIG. 1 of the drawing. Its viscosity of about m m Pa.s for a shear rate of 20 s1, decreases to 3.2.103 for a shear rate D 1 of 1.3.103.

On réalise en premier lieu le contact arrière sur un disque de silicium monocristallin de 100 mm de diamètre par sérigraphie d'une encre à l'argent, de façon connue, la cuisson ayant lieu en 5 minutes à environ 680 C.  First, the rear contact is made on a monocrystalline silicon disc 100 mm in diameter by screen printing with silver ink, in known manner, the baking taking place in 5 minutes at around 680 C.

On effectue ensuite la sérigraphie sur la face avant du disque de silicium à une vitesse de 5 cm/minutes, avec une émulsion d'épaisseur 20 microns et un écran en toile d'acier inoxydable, la trame étant à 450 par rapport au motif. The screen printing is then carried out on the front face of the silicon disc at a speed of 5 cm / minute, with an emulsion 20 microns thick and a screen made of stainless steel fabric, the screen being 450 relative to the pattern.

On effectue alors l'évaporation du solvant organique en chauffant à 120 -150 C pendant environ 15 minutes. The organic solvent is then evaporated by heating to 120-150 ° C for about 15 minutes.

La cuisson du contact a lieu dans un four à passage en présence d'air, en deux paliers. Un premier palier à 3500C pendant 5 à 10 minutes, assure la cuisson du liant. Un second palier, à 5900C pendant 5 minutes, assure le frittage et l'adhérence du contact sur la surface du silicium. Contact cooking takes place in a passage oven in the presence of air, in two stages. A first level at 3500C for 5 to 10 minutes, ensures the baking. A second bearing, at 5900C for 5 minutes, ensures sintering and adhesion of the contact to the surface of the silicon.

On procède alors au recuit de l'ensemble des contacts avant et arrière, en atmosphère réductrice, constituée par exemple d'un mélange à 90% d'azote et 10% d'hydrogène en volume, vers 3500C pendant 5 minutes. One then proceeds to the annealing of all the front and rear contacts, in a reducing atmosphere, consisting for example of a mixture of 90% nitrogen and 10% hydrogen by volume, around 3500C for 5 minutes.

Une cellule ainsi obtenue, de profondeur de jonction 0,5 à 0,6 micron, texturisée en face avant, mais non munie d'une couche anti-reflet, présente un rendement d'environ 10%, avec une tension en circuit ouvert de 576 millivolts et une intensité de court-circuit d'environ 2,1 ampères sous un éclairement de 0,1 watt/cm2. Les courants de fuite dans la jonction sont faibles et équivalents à ceux mesurés pour des contacts à l'argent. A cell thus obtained, with a junction depth of 0.5 to 0.6 microns, textured on the front face, but not provided with an anti-reflection layer, has an efficiency of approximately 10%, with an open circuit voltage of 576 millivolts and a short-circuit current of approximately 2.1 amps under an illumination of 0.1 watt / cm2. The leakage currents in the junction are low and equivalent to those measured for silver contacts.

On peut éventuellement procéder à la cuisson simultanée des contacts avant et arrière, mais sans dépasser la température de 590 C. Il y a lieu dans ce cas d'utiliser un contact arrière à l'aluminium. Optionally, the front and rear contacts can be baked simultaneously, but without exceeding the temperature of 590 C. In this case, use a rear aluminum contact.

Bien que l'encre conductrice et le procédé de réalisation d'un contact par sérigraphie qui viennent d'être décrits dans l'exemple ci-dessus paraissent les formes de réalisation préférables de l'invention, on comprendra que diverses modifications peuvent leur être apportées sans sortir du cadre de l'invention. L'invention s'applique à la fabrication de cellules photovoltaiques en silicium monocristallin ou polycristallin.  Although the conductive ink and the method of producing a contact by screen printing which have just been described in the example above appear to be the preferred embodiments of the invention, it will be understood that various modifications can be made to them without departing from the scope of the invention. The invention applies to the manufacture of photovoltaic cells in monocrystalline or polycrystalline silicon.

Claims (9)

REVENDICATIONS 1/ Encre conductrice pour prise de contact par sérigraphie sur une surface de silicium à jonction semi-conductrice, cette encre étant destinée à former après cuisson un dépôt conducteur constitué par ses matériaux permanents, et comportant - un matériau permanent actif en poudre en majeure partie métallique dont les grains conduiront l'électricité au sein du dépôt, - un matériau permanent passif constitué de grains de verre et devant assurer l'adhérence du dépôt sur le silicium, le coefficient de dilatation du verre étant voisin de celui du silicium, - un liant temporaire organique propre à rendre l'encre thixotropique et pouvant s'éliminer par pyrolyse sans charbonner, - et un solvant éliminable par séchage, cette encre #étant caractérisée en ce que son matériau permanent actif contient essentiellement de la poudre de nickel additionnée d'une moindre quantité de poudre de bore.1 / Conductive ink for making contact by screen printing on a silicon surface with semiconductor junction, this ink being intended to form, after firing, a conductive deposit consisting of its permanent materials, and comprising - a mainly active permanent powder material metallic, the grains of which will conduct electricity within the deposit, - a passive permanent material consisting of glass grains and having to ensure the adhesion of the deposit to the silicon, the coefficient of expansion of the glass being close to that of silicon, - a temporary organic binder capable of rendering the ink thixotropic and capable of being eliminated by pyrolysis without carbon, - and a solvent which can be removed by drying, this ink # being characterized in that its permanent active material contains essentially nickel powder with added less boron powder. 2/ Encre conductrice selon la revendication 1, caractérisée en ce que son matériau permanent actif contient 80 à 97% en poids de poudre de nickel et 3 à 20% en poids de poudre de bore.2 / conductive ink according to claim 1, characterized in that its active permanent material contains 80 to 97% by weight of nickel powder and 3 to 20% by weight of boron powder. 3/ Encre conductrice selon la revendication 2, caractérisée en ce que son matériau permanent actif contient environ 89% en poids de poudre de nickel et 11% de poudre de bore.3 / conductive ink according to claim 2, characterized in that its active permanent material contains about 89% by weight of nickel powder and 11% of boron powder. 4/ Encre conductrice selon l'une des revendications 1 à 3, caractérisée en ce que sa poudre de nickel est de granulométrie inférieure à 20 microns.4 / conductive ink according to one of claims 1 to 3, characterized in that its nickel powder is of particle size less than 20 microns. 5/ Encre conductrice selon l'une des revendications 1 à 4, caractérisée en ce qu'elle contient de 3 à 25% en poids de poudre de verre.5 / conductive ink according to one of claims 1 to 4, characterized in that it contains from 3 to 25% by weight of glass powder. 6/ Encre conductrice selon l'une des revendications 1 à 5, caractérisée en ce que le verre est un borosilicate de plomb en grains de dimension inférieure à 20 microns.6 / conductive ink according to one of claims 1 to 5, characterized in that the glass is a lead borosilicate in grains of dimension less than 20 microns. 7/ Encre conductrice selon l'une des revendications 1 à 6, caractérisée en ce qu'elle contient 75% en poids d'une partie minérale à 80% en poids de poudre de nickel, 10% en poids de poudre de verre et 10% en poids de poudre de bore, et 25% en poids de produits organiques comprenant au moins un solvant et un liant, en proportions telles que la viscosité de l'encre varie de 2,65.10# à 3,2.103 m Pa.s environ pour un taux de cisaillement compris entre 20 et 1300 8/ Procédé de réalisation d'un contact par sérigraphie sur un disque de silicium semi-conducteur, ce procédé comportant a/ un dépôt par sérigraphie sur le silicium d'une encre conductrice selon l'une des revendications 1 à 7, b/ un chauffage modéré pour évaporer le solvant, c/ une pyrolyse du liant, d/ un frittage de l'encre en présence d'air assurant son adhésion sur le silicium, e/ un recuit sous atmosphère réductrice, caractérisé en ce que le frittage de l'encre est assure par chauffage à une température au plus égale à 6000C pendant environ 5 minutes.7 / conductive ink according to one of claims 1 to 6, characterized in that it contains 75% by weight of a mineral part to 80% by weight of nickel powder, 10% by weight of glass powder and 10 % by weight of boron powder, and 25% by weight of organic products comprising at least one solvent and one binder, in proportions such that the viscosity of the ink varies from 2.65.10 # to 3.2.103 m Pa.s approximately for a shear rate of between 20 and 1300 8 / Process for producing a contact by screen printing on a semiconductor silicon disc, this process comprising a / a deposit by screen printing on silicon of a conductive ink according to one of claims 1 to 7, b / moderate heating to evaporate the solvent, c / pyrolysis of the binder, d / sintering of the ink in the presence of air ensuring its adhesion to silicon, e / annealing in an atmosphere reducing, characterized in that the sintering of the ink is ensured by heating to a temperature at most equal to 6000C p lasts about 5 minutes. 9/ Procédé selon la revendication 8, dans lequel on dépose sur la face avant du disque de silicium l'encre conductrice au nickel et au bore, et sur sa face arrière une encre conductrice à l'argent ou à l'aluminium, caractérisé en ce que l'on effectue chauffage, pyrolyse et frittage séparément sur les faces avant et arrière, le frittage sur la face avant ayant lieu à 5900C pendant environ 5 minutes, et celui sur la face arrière à au moins 6500C pendant environ 10 minutes. 9 / A method according to claim 8, wherein there is deposited on the front of the silicon disc the conductive ink with nickel and boron, and on its rear face a conductive ink with silver or aluminum, characterized in what is carried out heating, pyrolysis and sintering separately on the front and rear sides, the sintering on the front side taking place at 5900C for about 5 minutes, and that on the back side at least 6500C for about 10 minutes. 10/ Cellule photovoltalque à disque de silicium à jonction semi-conductrice, caractérisée en ce qu'elle comporte au moins en face avant un contact obtenu par le procédé de réalisation selon la revendication 8 à l'aide d'une encre selon la revendication 1. 10 / Photovoltaic cell with silicon disc with semiconductor junction, characterized in that it comprises at least on the front face a contact obtained by the production method according to claim 8 using an ink according to claim 1 .
FR8311718A 1983-07-13 1983-07-13 CONDUCTIVE INK FOR PRINTING CONTACT BY SERIGRAPHY ON SEMICONDUCTOR SILICON, METHOD FOR PRODUCING CONTACT BY SERIGRAPHY USING SUCH AN INK, AND PHOTOVOLTAIC CELL PROVIDED WITH SUCH A CONTACT Expired FR2549290B1 (en)

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Publication number Priority date Publication date Assignee Title
WO2010019532A2 (en) * 2008-08-13 2010-02-18 E. I. Du Pont De Nemours And Company Compositions and processes for forming photovoltaic devices
US8294024B2 (en) 2008-08-13 2012-10-23 E I Du Pont De Nemours And Company Processes for forming photovoltaic devices
US8710355B2 (en) 2008-12-22 2014-04-29 E I Du Pont De Nemours And Company Compositions and processes for forming photovoltaic devices
US8840701B2 (en) 2008-08-13 2014-09-23 E I Du Pont De Nemours And Company Multi-element metal powders for silicon solar cells

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FR2348897A1 (en) * 1976-04-21 1977-11-18 Labo Electronique Physique Screen printable conductive paste compsn. - using a sealing glass compsn. as the permanent binder
GB1497741A (en) * 1976-02-02 1978-01-12 Ferranti Ltd Formation of contacts for semiconductor devices
DE2829917A1 (en) * 1978-07-07 1980-01-24 Semikron Gleichrichterbau Solderable semiconductor unit prodn. - by coating with viscous mixt. of metal powder(s) in metal carbonyl, carbohydrate of liq. metal vehicle and heating
US4235644A (en) * 1979-08-31 1980-11-25 E. I. Du Pont De Nemours And Company Thick film silver metallizations for silicon solar cells
US4293451A (en) * 1978-06-08 1981-10-06 Bernd Ross Screenable contact structure and method for semiconductor devices
FR2515675A1 (en) * 1981-11-05 1983-05-06 Comp Generale Electricite Low cost, reliable, low resistance contacts for silicon semiconductors - using a nickel conducting ink

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GB1497741A (en) * 1976-02-02 1978-01-12 Ferranti Ltd Formation of contacts for semiconductor devices
FR2348897A1 (en) * 1976-04-21 1977-11-18 Labo Electronique Physique Screen printable conductive paste compsn. - using a sealing glass compsn. as the permanent binder
US4293451A (en) * 1978-06-08 1981-10-06 Bernd Ross Screenable contact structure and method for semiconductor devices
DE2829917A1 (en) * 1978-07-07 1980-01-24 Semikron Gleichrichterbau Solderable semiconductor unit prodn. - by coating with viscous mixt. of metal powder(s) in metal carbonyl, carbohydrate of liq. metal vehicle and heating
US4235644A (en) * 1979-08-31 1980-11-25 E. I. Du Pont De Nemours And Company Thick film silver metallizations for silicon solar cells
FR2515675A1 (en) * 1981-11-05 1983-05-06 Comp Generale Electricite Low cost, reliable, low resistance contacts for silicon semiconductors - using a nickel conducting ink

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010019532A2 (en) * 2008-08-13 2010-02-18 E. I. Du Pont De Nemours And Company Compositions and processes for forming photovoltaic devices
WO2010019532A3 (en) * 2008-08-13 2010-11-18 E. I. Du Pont De Nemours And Company Compositions and processes for forming photovoltaic devices
US8294024B2 (en) 2008-08-13 2012-10-23 E I Du Pont De Nemours And Company Processes for forming photovoltaic devices
US8840701B2 (en) 2008-08-13 2014-09-23 E I Du Pont De Nemours And Company Multi-element metal powders for silicon solar cells
US8710355B2 (en) 2008-12-22 2014-04-29 E I Du Pont De Nemours And Company Compositions and processes for forming photovoltaic devices

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