EP0000864B1 - Process for manufacturing thick film varistors - Google Patents
Process for manufacturing thick film varistors Download PDFInfo
- Publication number
- EP0000864B1 EP0000864B1 EP78100192A EP78100192A EP0000864B1 EP 0000864 B1 EP0000864 B1 EP 0000864B1 EP 78100192 A EP78100192 A EP 78100192A EP 78100192 A EP78100192 A EP 78100192A EP 0000864 B1 EP0000864 B1 EP 0000864B1
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- European Patent Office
- Prior art keywords
- varistor
- thick
- paste
- film
- varistors
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
- H01C7/1006—Thick film varistors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
- H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
- H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits
- H01C17/06513—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component
- H01C17/06533—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component composed of oxides
- H01C17/06546—Oxides of zinc or cadmium
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49082—Resistor making
Definitions
- the invention relates to a method for producing thick film varistors with zinc oxide as the main component, in which the varistor materials and an organic binder are applied as varistor paste to an insulating substrate and are converted into a thick film varistor by sintering the varistor paste.
- the current flowing through the varistor, V the applied voltage, C a constant and the exponent n denote the so-called steepness of the varistor.
- the numerical value of the slope n should be as high as possible, since this exponent indicates the degree of deviation of the varistor from an ohmic characteristic.
- the known varistors are generally designed as discrete components, which are produced by pressing and sintering the pulverized varistor materials. From US Pat. No. 3,725,836 it is also already known to produce varistors in thick-film technology and to integrate them directly into thick-film circuits. To produce these known thick-film varistors belonging to the group of ZnO varistors, the varistor materials are mixed with glass frit and an organic binder, applied as a screen-printable varistor paste to an insulating substrate and sintered to form the varistor. The electrodes required for contacting the varistor can then also be applied to the surface of the varistor using thick-film technology. The steep he i tn thick film of the varistors produced in this manner is in the order 4-8 and is therefore for the most applications too low.
- DE-A-2 446 708 describes the production of varistor material without glass components, which has the greatest possible steepness.
- the material dealt with in this published publication relates to the classic manufacture of varistor components, which amounts to a powder pressing technique.
- This manufacturing method involves a discrete varistor, which e.g. is soldered into a plastic circuit board.
- the invention has for its object to provide a method for producing thick film varistors with improved values of the slope n.
- the invention is a thick film varistor that can be integrated with resistors and conductor tracks, the structures of which are e.g. applied by screen printing.
- glass frit is always used as an inorganic binder in conductor pastes, resistance pastes and the known varistor pastes.
- the pastes mentioned are sintered, the glass frit forms a solid glass matrix, which ensures the cohesion of the other solids and the bond to the substrate.
- varistor paste which contains 87.5 to 98.0% by weight of zinc oxide, based on the solids content.
- a varistor paste which contains bismuth oxide, tricobalt tetroxide and manganese dioxide is advantageously used.
- the addition of these oxides to the zinc oxide favors the crystal formation in the manufacture of the thick film varistor and thus leads to a further improvement in the electrical properties.
- a varistor paste which relates to the solids content contains.
- Thick film varistors produced with such a varistor paste are particularly suitable for higher operating voltages. These operating voltages are, for example, in the range of 200 volts per millimeter of active varistor material.
- a varistor paste which relates to the solids content contains.
- Thick film varistors produced with such a varistor paste are particularly suitable for lower operating voltages. These operating voltages are, for example, in the range of 30 V / mm active varistor material.
- the response voltage of the thick-film varistor can also be influenced by the choice of temperature.
- the peak temperature during sintering of the varistor paste is preferably maintained for a period of between 5 and 20 minutes.
- a further advantage of the crystal formation and thus a further improvement of the electrical properties can be achieved in that the thick film varistor is cooled after the sintering at a temperature gradient between 2 and 8 ° C / min.
- the varistor paste is preferably applied to the insulating substrate in such a way that the thick-film varistor has a thickness between 100 and 200 ⁇ m after sintering. With such thick film varistor thicknesses, particularly favorable electrical properties are achieved.
- a varistor paste that could be screen-printed was first produced from the varistor materials.
- the powdery solids were weighed in as follows:
- the solids were wet-mixed and ground in ball mills for 18 hours, then freed of water by filter suction and then dried in a drying oven at a temperature of 150 ° C. for 24 hours.
- the maximum particle size distribution of the powder mixture after this treatment was 1 ⁇ m.
- an organic binder 75 g of an organic binder were mixed into a batch of 100 g of the powder mixture thus prepared and homogenized on a roller mill.
- Other known organic binders such as e.g. a solution of nitrocellulose in butyl carbitol acetate are equally suitable.
- the viscosity and flow behavior of the varistor paste produced in this way was adjusted so that it could be processed using the screen printing process.
- the finished varistor paste was then screen printed onto an insulating substrate made of A1 2 0 3 ceramic at the locations provided for the varistors.
- the approx. 150 ⁇ m thick layer of varistor paste was then dried in a drying oven at a temperature of approx. 60 ° C.
- the varistor properties were formed. Sintering was carried out in an oxidizing atmosphere at a temperature between 1 100 and 1 200 ° C, the peak temperature being held for 10 minutes. The temperature increase during heating was about 10 ° C per minute, while a temperature drop of 7 ° C per minute was observed during cooling.
- the thick-film varistors produced according to the procedure described above are particularly suitable for operating voltages in the Suitable range of 200 volts per millimeter of active varistor material.
- the powdered varistor materials were first weighed out as follows:
- the powdery varistor materials were then processed in the manner described in Example 1 to form a screen-printable varistor paste and screen-printed onto an insulating substrate made of A1 2 0 3 - Ceramic printed.
- the approx. 150 ⁇ m thick layer of varistor paste was then dried at a temperature of approx. 60 ° C.
- the subsequent sintering was carried out at a temperature between 1 100 and 1 200 ° C, the peak temperature being held for 10 minutes.
- the temperature increase during heating was about 10 ° C per minute, while when cooling down to a temperature of approx. 1000 ° C a temperature drop of 3 ° C per minute and below 1000 ° C a temperature drop of 6 to 7 ° C per minute Minute was observed.
- the varistor electrodes and the other elements of the thick-film circuit can be produced in a known manner.
- the fully contacted thick film varistors again had excellent electrical properties compared to the known glass thick film varistors.
- the thick-film varistors produced according to the procedure described above are particularly suitable for operating voltages in the range of 30 volts per millimeter of active varistor material.
- thick-film circuits with integrated thick-film varistors can be produced.
- thick film varistors as discrete components.
- a large number of varistor elements are applied and sintered on an insulating substrate using the screen printing process.
- conductor tracks for contacting the varistor elements are applied using screen printing technology, dried and sintered.
- the substrate is then perforated in a known manner, for example with the aid of a laser, and separated into individual elements. These individual elements can then be soldered into printed circuits or layer circuits as so-called varistor chips.
Description
Die Erfindung betrifft ein Verfahren zur Herstellung von Dickfilm-Varistoren mit Zinkoxid als Hauptkomponente, bei welchem die Varistormaterialien und ein organisches Bindemittel als Varistorpaste auf ein isolierendes Substrat aufgebracht und durch Sintern der Varistorpaste in einen Dickfilmvaristor überführt werden.The invention relates to a method for producing thick film varistors with zinc oxide as the main component, in which the varistor materials and an organic binder are applied as varistor paste to an insulating substrate and are converted into a thick film varistor by sintering the varistor paste.
Varistoren sind spannungsabhängige Widerstände, die bis zu einer bestimmten Spannung, der sog. Varistor-Ansprech-spannung einen möglichst hohen Widerstand aufweisen sollen. Wird die Spannung über die Varistor-Ansprech- spannung. hinaus erhöht, so tritt ein steiler Leitfähigkeitsanstieg ein, wobei die Strom-Spannungscharakteristik durch die folgende Gleichung ausgedrückt werden kann : 1 = (V/C)"Varistors are voltage-dependent resistors that should have the highest possible resistance up to a certain voltage, the so-called varistor response voltage. If the voltage is above the varistor response voltage. increases, a steep increase in conductivity occurs, and the current-voltage characteristic can be expressed by the following equation: 1 = (V / C) "
Hierbei ist mit der durch den Varistor fließende Strom, mit V die angelegte Spannung, mit C eine Konstante und mit dem Exponenten n die sog. Steilheit des Varistors bezeichnet. Der Zahlenwert der Steilheit n soll möglichst hoch sein, da dieser Exponent den Grad der Abweichung des Varistors von einer ohmschen Charakteristik angibt.The current flowing through the varistor, V the applied voltage, C a constant and the exponent n denote the so-called steepness of the varistor. The numerical value of the slope n should be as high as possible, since this exponent indicates the degree of deviation of the varistor from an ohmic characteristic.
Die bekannten Varistoren sind in der Regel als diskrete Bauelemente ausgebildet, welche durch Pressen und Sintern der pulverisierten Varistor- materialien hergestellt werden. Aus der US-PS 3 725 836 ist es auch bereits bekannt, Varistoren in Dickschichttechnik herzustellen und direkt in Dickschichtschaltungen zu integrieren. Zur Herstellung dieser bekannten zur Gruppe der ZnO-Varistoren gehörenden Dickfilm-Varistoren werden die Varistormaterialien mit Glasfritte und einem organischen Bindemittel vermischt, als siebdruckfähige Varistorpaste auf ein isolierendes Substrat aufgebracht und zur Bildung des Varistors gesintert. Die zur Kontaktierung des Varistors erforderlichen Elektroden können dann ebenfalls in Dickschicht-technik auf die Oberfläche des Varistors aufgebracht werden. Die Steil- heit n der auf diese Weise hergestellten Dickfilm- Varistoren liegt in der Größenordnung zwischen 4 und 8 und ist somit für die meisten Anwendungsfälle zu gering.The known varistors are generally designed as discrete components, which are produced by pressing and sintering the pulverized varistor materials. From US Pat. No. 3,725,836 it is also already known to produce varistors in thick-film technology and to integrate them directly into thick-film circuits. To produce these known thick-film varistors belonging to the group of ZnO varistors, the varistor materials are mixed with glass frit and an organic binder, applied as a screen-printable varistor paste to an insulating substrate and sintered to form the varistor. The electrodes required for contacting the varistor can then also be applied to the surface of the varistor using thick-film technology. The steep he i tn thick film of the varistors produced in this manner is in the order 4-8 and is therefore for the most applications too low.
In der DE-A-2 446 708 wird die Herstellung von Varistor-material ohne Glasanteile beschrieben, das eine möglichst große Steilheit hat. Das in dieser Offenlegungsschrift behandelte Material betrifft aber die klassische Herstellung von Varistor-Bauelementen, die auf eine Pulver-Preßtechnik hinausläuft. Diese Herstellmethode hat einen diskreten Varistor zum Gegenstand, der z.B. in eine Kunststoff-Leiterplatte gelötet wird.DE-A-2 446 708 describes the production of varistor material without glass components, which has the greatest possible steepness. However, the material dealt with in this published publication relates to the classic manufacture of varistor components, which amounts to a powder pressing technique. This manufacturing method involves a discrete varistor, which e.g. is soldered into a plastic circuit board.
Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Herstellung von Dickfilmvaristoren mit verbesserten Werten der Steilheit n anzugeben.The invention has for its object to provide a method for producing thick film varistors with improved values of the slope n.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß bei einem Verfahren der eingangs genannten Art eine glasfreie Varistorpaste verwendet wird. Im Gegensatz zu der DE-A-2446708 handelt es sich bei der Erfindung um einen Dickfilmvaristor, der mit Widerständen und Leiterbahnen integrierbar ist, dessen Strukturen z.B. mittels Siebdruck aufgebracht werden.This object is achieved in that a glass-free varistor paste is used in a method of the type mentioned. In contrast to DE-A-2446708, the invention is a thick film varistor that can be integrated with resistors and conductor tracks, the structures of which are e.g. applied by screen printing.
In der Dickschichttechnik wird bei Leiterbahnpasten, Widerstandspasten und den bekannten Varistorpasten stets Glasfritte als anorganisches Bindemittel eingesetzt. Beim Sintern der genannten Pasten bildet die Glasfritte eine feste Glasmatrix, welche den Zusammenhalt der übrigen Feststoffe und die Bindung zum Substrat gewährleistet.In thick-film technology, glass frit is always used as an inorganic binder in conductor pastes, resistance pastes and the known varistor pastes. When the pastes mentioned are sintered, the glass frit forms a solid glass matrix, which ensures the cohesion of the other solids and the bond to the substrate.
Gemäß der vorliegenden Erfindung wurde nun herausgefunden, daß bei Varistorpasten mit Zinkoxid als Hauptkomponente überraschenderweise auch ohne Anwesenheit von Glasfritte ein stabiler Zusammenhalt der Feststoffe und eine gute Bindung zum Substrat erzielt werden kann. Andererseits werden durch die Abwesenheit der Glasfritte die elektrischen Eigenschaften der fertigen Dickfilm-Varistoren erheblich verbessert, d.h. es können ohne weiteres Steilheiten der Varistoren mit einem Zahlenwert des Exponenten n von über 20 erzielt werden.According to the present invention, it has now been found that, in the case of varistor pastes with zinc oxide as the main component, a stable cohesion of the solids and a good bond to the substrate can surprisingly be achieved even without the presence of glass frit. On the other hand, the absence of the glass frit significantly improves the electrical properties of the finished thick film varistors, i.e. it is easily possible to achieve slopes of the varistors with a numerical value of the exponent n of more than 20.
Hinsichtlich der Bindung und der elektrischen Eigenschaften des Varistors ist es besonders günstig, wenn eine Varistorpaste verwendet wird, welche auf den Feststoff-anteil bezogen 87,5 bis 98,0 Gew.-% Zinkoxid enthält.With regard to the binding and the electrical properties of the varistor, it is particularly advantageous if a varistor paste is used which contains 87.5 to 98.0% by weight of zinc oxide, based on the solids content.
Vorteilhaft wird eine Varistorpaste verwendet, welche Wismutoxid, Trikobalt-Tetroxid und Mangandioxid enthält. Der Zusatz dieser Oxide zum Zinkoxid begünstigt die Kristallausbildung bei der Herstellung des Dickfilm-Varistors und führt somit zu einer weiteren Verbesserung der elektrischen Eigenschaften.A varistor paste which contains bismuth oxide, tricobalt tetroxide and manganese dioxide is advantageously used. The addition of these oxides to the zinc oxide favors the crystal formation in the manufacture of the thick film varistor and thus leads to a further improvement in the electrical properties.
Bei einer ersten bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens wird eine Varistorpaste verwendet, welche auf den Feststoffanteil bezogen
Bei einer zweiten bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens wird eine Varistorpaste verwendet, welche auf den Feststoffanteil bezogen
Weiterhin hat es sich als besonders günstig herausgestellt, die Varistorpaste bei einer Temperatur zwischen 1100 und 1360°C zu sintern. Durch die Wahl der Temperatur kann hierbei auch die Ansprechspannung des Dickfilm-Varistors beeinflußt werden. Vorzugsweise wird die Spitzentemperatur beim Sintern der Varistorpaste für eine Zeitdauer zwischen 5 und 20 Minuten aufrechterhalten.Furthermore, it has proven particularly favorable to sinter the varistor paste at a temperature between 1100 and 1360 ° C. The response voltage of the thick-film varistor can also be influenced by the choice of temperature. The peak temperature during sintering of the varistor paste is preferably maintained for a period of between 5 and 20 minutes.
Eine weitere Begünstigung der Kristallausbildung und somit eine weitere Verbesserung der elektrischen Eigenschaften kann dadurch erzielt werden, daß der Dickfilm-Varistor nach dem Sintern bei einem Temperaturgefälle zwischen 2 und 8°C/min abgekühlt wird.A further advantage of the crystal formation and thus a further improvement of the electrical properties can be achieved in that the thick film varistor is cooled after the sintering at a temperature gradient between 2 and 8 ° C / min.
Vorzugsweise wird die Varistorpaste derart auf das isolierende Substrat aufgebracht, daß der Dickfilm-Varistor nach dem Sintern eine Stärke zwischen 100 und 200 µm aufweist. Bei derartigen Stärken der Dickfilm-Varistoren werden besonders günstige elektrische Eigenschaften erzielt.The varistor paste is preferably applied to the insulating substrate in such a way that the thick-film varistor has a thickness between 100 and 200 μm after sintering. With such thick film varistor thicknesses, particularly favorable electrical properties are achieved.
Zur Herstellung eines Dickfilm-Varistors wurde zunächst aus den Varistormaterialien eine sieb-druckfähige Varistorpaste hergestellt. Hierzu wurden die pulverförmigen Feststoffe wie folgt eingewogen :
Nach der Einwaage wurden die Feststoffe in Kugelmühlen 18 Stunden lang naß gemischt und gemahlen, sodann über Filternutschen vom Wasser befreit und anschließend in einem Trockenofen bei einer Temperatur von 150 °C 24 Stunden lang getrocknet. Das Maximum der Korngrößenverteilung des Pulvergemisches lag nach dieser Behandlung bei 1 µm.After weighing, the solids were wet-mixed and ground in ball mills for 18 hours, then freed of water by filter suction and then dried in a drying oven at a temperature of 150 ° C. for 24 hours. The maximum particle size distribution of the powder mixture after this treatment was 1 µm.
Zu einem Ansatz des derart hergestellten Pulvergemisches von 100 g wurden 75 g eines organischen Bindemittels gemischt und auf einem Walzenstuhl homogenisiert. Als organisches Bindemittel wurde hierbei eine in der Dick-schichttechnik übliche Lösung von 10 % Äthylzellulose in 90 % Terpineol-Isomerengemisch verwendet. Andere bekannte organische Bindemittel, wie z.B. eine Lösung aus Nitrozellulose in Butylcarbitolacetat sind in gleicher Weise geeignet. Die auf diese Weise hergestellte Varistorpaste war in ihrer Viskosität und ihrem Fließverhalten so eingestellt, daß sie im Siebdruckverfahren verarbeitet werden konnte.75 g of an organic binder were mixed into a batch of 100 g of the powder mixture thus prepared and homogenized on a roller mill. A solution of 10% ethyl cellulose in 90% terpineol isomer mixture, which is customary in thick-film technology, was used as the organic binder. Other known organic binders such as e.g. a solution of nitrocellulose in butyl carbitol acetate are equally suitable. The viscosity and flow behavior of the varistor paste produced in this way was adjusted so that it could be processed using the screen printing process.
Dementsprechend wurde die fertige Varistorpaste dann im Siebdruckverfahren auf ein isolierendes Substrat aus A1203-Keramik an den für Varistoren vorgesehenen Stellen aufgedruckt. Anschließend wurde die ca. 150 µm starke Schicht der Varistorpaste in einem Trockenofen bei einer Temperatur von ca. 60 °C getrocknet. Beim nachfolgenden Sinterprozeß, bei welchem die Feststoffe der Varistorpaste untereinander und an das Substrat gebunden wurden, bildeten sich die Varistoreigenschaften aus. Das Sintern erfolgte in oxydierender Atmosphäre bei einer Temperatur zwischen 1 100 und 1 200°C, wobei die Spitzentemperatur 10 Minuten lang gehalten wurde. Der Temperaturanstieg beim Aufheizen betrug hierbei etwa 10°C pro Minute, während beim Abkühlen ein Temperaturabfall von 7°C pro Minute eingehalten wurde.Accordingly, the finished varistor paste was then screen printed onto an insulating substrate made of A1 2 0 3 ceramic at the locations provided for the varistors. The approx. 150 µm thick layer of varistor paste was then dried in a drying oven at a temperature of approx. 60 ° C. In the subsequent sintering process, in which the solids of the varistor paste were bound to one another and to the substrate, the varistor properties were formed. Sintering was carried out in an oxidizing atmosphere at a temperature between 1 100 and 1 200 ° C, the peak temperature being held for 10 minutes. The temperature increase during heating was about 10 ° C per minute, while a temperature drop of 7 ° C per minute was observed during cooling.
Da alle anderen bekannten Dickschicht-Prozesse im Temperaturbereich von ca. 500 °C bis 1 000°C ablaufen, ist es erforderlich, daß die Dickfilm-Varistoren vor den anderen Dickschichtelementen wie Leiterbahnen und Widerständen hergestellt werden. Dementsprechend wurden im vorliegenden Fall die Leiterbahnen bzw. Elektroden zur Kontaktierung der Dickfilm-Varistoren nach dem Sintern der Varistoren in bekannter Weise nach dem Siebdruckverfahren gedruckt, getrocknet und anschließend gesintert. Die fertig kontaktierten Dickfilmvaristoren weisen im Vergleich zu den bekannten glashaltigen Dickfilm- Varistoren hervorragende elektrische Eigenschaften auf. Bei Verwendung von in Dickschicht- technik hergestellten Elektroden auf der Basis von Gold-Platin einer Dicke der Dickfilm-Varistoren von 130 µm ergab sich beispielsweise eine Steilheit von n = 25. Die nach der vorstehend beschriebenen Verfahrensweise hergestellten Dickfilm-Varistoren sind insbesondere für Betriebsspannungen im Bereich von 200 Volt pro Millimeter aktiven Varistormaterial geeignet.Since all other known thick-film processes take place in the temperature range from approximately 500 ° C. to 1000 ° C., it is necessary for the thick-film varistors to be produced before the other thick-film elements such as conductor tracks and resistors. Accordingly, in the present case, the conductor tracks or electrodes for contacting the thick film varistors after sintering the varistors were printed in a known manner by the screen printing process, dried and then sintered. The fully contacted thick film varistors have excellent electrical properties compared to the known thick film varistors containing glass. When using electrodes produced in thick-film technology based on gold-platinum with a thickness of the thick-film varistors of 130 μm, the slope was, for example, n = 25. The thick-film varistors produced according to the procedure described above are particularly suitable for operating voltages in the Suitable range of 200 volts per millimeter of active varistor material.
Zur Herstellung eines Dickfilm-Varistors wurden zunächst die pulverförmigen Varistormaterialien wie folgt eingewogen :
Nach der Einwaage wurden dann die pulverförmigen Varistor-materialien in der in Beispiel 1 beschriebenen Weise zu einer siebdruckfähigen Varistorpaste verarbeitet und im Siebdruckverfahren auf ein isolierendes Substrat aus A1203-Keramik aufgedruckt. Anschließend wurde die ca. 150 µm starke Schicht der Varistorpaste bei einer Temperatur von ca. 60 °C getrocknet. Das nachfolgende Sintern erfolgte bei einer Temperatur zwischen 1 100 und 1 200 °C, wobei die Spitzentemperatur 10 Minuten lang gehalten wurde. Der Temperaturanstieg beim Aufheizen betrug hierbei etwa 10 °C pro Minute, während beim Abkühlen bis zu einer Temperatur von ca. 1 000 °C ein Temperaturabfall von 3°C pro Minute und unterhalb 1 000°C ein Temperaturabfall von 6 bis 7°C pro Minute eingehalten wurde.After weighing in, the powdery varistor materials were then processed in the manner described in Example 1 to form a screen-printable varistor paste and screen-printed onto an insulating substrate made of A1 2 0 3 - Ceramic printed. The approx. 150 µm thick layer of varistor paste was then dried at a temperature of approx. 60 ° C. The subsequent sintering was carried out at a temperature between 1 100 and 1 200 ° C, the peak temperature being held for 10 minutes. The temperature increase during heating was about 10 ° C per minute, while when cooling down to a temperature of approx. 1000 ° C a temperature drop of 3 ° C per minute and below 1000 ° C a temperature drop of 6 to 7 ° C per minute Minute was observed.
Nach dem Abkühlen der derart auf das AI203-Substrat aufgebrachten Dickfilm-Varistoren, können die Varistor-Elektroden und die übrigen Elemente der Dickschicht-schaltung in bekannter Weise hergestellt werden. Die fertig kontaktierten Dickfilm-Varistoren wiesen wieder im Vergleich zu den bekannten glashaltigen Dickfilm-Varistoren hervorragende elektrische Eigenschaften auf. Bei Verwendung von in Dickschichttechnik hergestellten Elektroden auf der Basis von Gold-Platin und einer Stärke der Dickfilm-Varistoren von 130 µm ergab sich beispielsweise eine Steilheit von n = 25. Die nach der vorstehend beschriebenen Verfahrensweise hergestellten Dickfilm-Varistoren sind insbesondere für Betriebsspannungen im Bereich von 30 Volt pro Millimeter aktivem Varistor-material geeignet.After the thick-film varistors applied in this way to the Al 2 O 3 substrate have cooled, the varistor electrodes and the other elements of the thick-film circuit can be produced in a known manner. The fully contacted thick film varistors again had excellent electrical properties compared to the known glass thick film varistors. When using electrodes made in thick-film technology on the basis of gold-platinum and a thickness of the thick-film varistors of 130 μm, for example, the slope was n = 25. The thick-film varistors produced according to the procedure described above are particularly suitable for operating voltages in the range of 30 volts per millimeter of active varistor material.
Mit Hilfe des erfindungsgemäßen Verfahrens können, wie es in den Beispielen 1 und 2 beschrieben wurde, Dickschichtschaltungen mit integrierten Dickfilm-Varistoren hergestellt werden. Es ist jedoch auch möglich Dickfilm-Varistoren als diskrete Bauelemente herzustellen. Hierzu wird beispielsweise auf ein isolierendes Substrat eine Vielzahl von Varistor-Elementen im Siebdruckverfahren aufgebracht und gesintert. Anschließend werden Leiterbahnen zur Kontaktierung der Varistor-Elemente in Siebdrucktechnik aufgebracht, getrocknet und gesintert. Daraufhin wird das Substrat beispielsweise mit Hilfe eines Lasers in bekannter Weise perforiert und in Einzelelemente aufgetrennt. Diese Einzelelemente können dann als sogenannte Varistor-Chips in gedruckte Schaltungen oder Schichtschaltungen eingelötet werden.With the aid of the method according to the invention, as described in Examples 1 and 2, thick-film circuits with integrated thick-film varistors can be produced. However, it is also possible to produce thick film varistors as discrete components. For this purpose, for example, a large number of varistor elements are applied and sintered on an insulating substrate using the screen printing process. Subsequently, conductor tracks for contacting the varistor elements are applied using screen printing technology, dried and sintered. The substrate is then perforated in a known manner, for example with the aid of a laser, and separated into individual elements. These individual elements can then be soldered into printed circuits or layer circuits as so-called varistor chips.
Claims (8)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2735484A DE2735484C2 (en) | 1977-08-05 | 1977-08-05 | Process for the production of thick film varistors with zinc oxide as the main component |
| DE2735484 | 1977-08-05 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0000864A1 EP0000864A1 (en) | 1979-03-07 |
| EP0000864B1 true EP0000864B1 (en) | 1981-04-15 |
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ID=6015775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP78100192A Expired EP0000864B1 (en) | 1977-08-05 | 1978-06-19 | Process for manufacturing thick film varistors |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4186367A (en) |
| EP (1) | EP0000864B1 (en) |
| JP (1) | JPS5928962B2 (en) |
| CA (1) | CA1117223A (en) |
| DE (1) | DE2735484C2 (en) |
| IT (1) | IT1097664B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3754458A (en) * | 1971-06-09 | 1973-08-28 | Polaroid Corp | Light seal for a reflex camera viewfinder |
| US4349496A (en) * | 1981-03-26 | 1982-09-14 | General Electric Company | Method for fabricating free-standing thick-film varistors |
| FR2512240A1 (en) * | 1981-08-25 | 1983-03-04 | Thomson Csf | ELECTRIC CONTROL VISUALIZATION DEVICE USING A THICK-LAYER NONLINEAR ELEMENT AND METHOD OF MANUFACTURING THE SAME |
| FR2545259B1 (en) * | 1983-04-29 | 1985-12-27 | Ceraver | ELECTRICAL INSULATOR HAVING IMPROVED POLLUTION INSENSITIVITY |
| DE3335195A1 (en) * | 1983-09-28 | 1985-04-04 | Siemens AG, 1000 Berlin und 8000 München | COMBINED CIRCUIT WITH VARISTOR |
| FR2726941A1 (en) * | 1986-01-28 | 1996-05-15 | Cimsa Cintra | INTEGRATED VARISTOR PROTECTION DEVICE OF AN ELECTRONIC COMPONENT AGAINST THE EFFECTS OF AN ELECTRO-MAGNETIC FIELD OR STATIC LOADS |
| JPS62190807A (en) * | 1986-02-18 | 1987-08-21 | 松下電器産業株式会社 | Manufacture of voltage nonlinear device |
| JPS62190801A (en) * | 1986-02-18 | 1987-08-21 | 松下電器産業株式会社 | Manufacture of voltage nonlinear device |
| JPS62193211A (en) * | 1986-02-20 | 1987-08-25 | 松下電器産業株式会社 | Manufacture of voltage nonlinear device |
| DE3619620A1 (en) * | 1986-06-11 | 1987-12-17 | Siemens Ag | Process for preparing ceramic zinc oxide varistor material and use of the material prepared according to this process |
| DE3627682A1 (en) * | 1986-08-14 | 1988-02-25 | Bbc Brown Boveri & Cie | PRECISION RESISTANCE NETWORK, ESPECIALLY FOR THICK-LAYER HYBRID CIRCUITS |
| US4803100A (en) * | 1987-10-21 | 1989-02-07 | International Business Machines Corporation | Suspension and use thereof |
| GB2242065C (en) * | 1990-03-16 | 1996-02-08 | Ecco Ltd | Varistor ink formulations |
| GB2242068C (en) * | 1990-03-16 | 1996-01-24 | Ecco Ltd | Varistor manufacturing method and apparatus |
| US5973588A (en) * | 1990-06-26 | 1999-10-26 | Ecco Limited | Multilayer varistor with pin receiving apertures |
| US6183685B1 (en) | 1990-06-26 | 2001-02-06 | Littlefuse Inc. | Varistor manufacturing method |
| JP3251134B2 (en) * | 1994-08-29 | 2002-01-28 | 松下電器産業株式会社 | Method for producing sintered zinc oxide |
| US6965510B1 (en) | 2003-12-11 | 2005-11-15 | Wilson Greatbatch Technologies, Inc. | Sintered valve metal powders for implantable capacitors |
| JP4432489B2 (en) * | 2003-12-25 | 2010-03-17 | パナソニック株式会社 | Manufacturing method of anti-static parts |
| JP4432586B2 (en) * | 2004-04-02 | 2010-03-17 | パナソニック株式会社 | Antistatic parts |
| CN101331562B (en) * | 2005-10-19 | 2011-06-01 | 东莞令特电子有限公司 | A varistor and production method |
| JP4835153B2 (en) * | 2005-12-22 | 2011-12-14 | 富士電機リテイルシステムズ株式会社 | Vending machine product delivery device |
| CN101506912B (en) * | 2006-09-19 | 2011-10-12 | 东莞令特电子有限公司 | Manufacture of varistors comprising a passivation layer |
| DE102007013986A1 (en) * | 2007-03-23 | 2008-09-25 | Osram Opto Semiconductors Gmbh | Optoelectronic component e.g. LED, has protective structure comprising material e.g. ceramic material or metal oxide e.g. zinc oxide, attached to structural element and/or to contact terminal, where material is provided as pasty mass |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE534523A (en) * | 1953-12-31 | 1900-01-01 | ||
| DE1180215B (en) * | 1962-05-18 | 1964-10-22 | Duerrwaechter E Dr Doduco | Solution of resinates of precious metals and / or base metals in chlorinated hydrocarbons for the production of thin precious metal layers or base metal oxide layers fired onto carrier materials for electrotechnical purposes |
| US3723175A (en) * | 1967-10-09 | 1973-03-27 | Matsushita Electric Ind Co Ltd | Nonlinear resistors of bulk type |
| CA831691A (en) * | 1967-10-09 | 1970-01-06 | Matsuoka Michio | Non-linear resistors of bulk type |
| GB1346851A (en) * | 1971-05-21 | 1974-02-13 | Matsushita Electric Ind Co Ltd | Varistors |
| US3768058A (en) * | 1971-07-22 | 1973-10-23 | Gen Electric | Metal oxide varistor with laterally spaced electrodes |
| US3877962A (en) * | 1972-12-18 | 1975-04-15 | Owens Illinois Inc | Substrate coating composition and process |
| US3905006A (en) * | 1972-12-29 | 1975-09-09 | Michio Matsuoka | Voltage dependent resistor |
| US3928245A (en) * | 1973-07-09 | 1975-12-23 | Gen Electric | Metal oxide voltage-variable resistor composition |
| US3857174A (en) * | 1973-09-27 | 1974-12-31 | Gen Electric | Method of making varistor with passivating coating |
| US3900432A (en) * | 1973-10-15 | 1975-08-19 | Du Pont | Varistor compositions |
| JPS5083789A (en) * | 1973-11-28 | 1975-07-07 | ||
| JPS5083790A (en) * | 1973-11-28 | 1975-07-07 | ||
| JPS50131095A (en) * | 1974-04-05 | 1975-10-16 | ||
| DE2446708A1 (en) * | 1974-09-30 | 1976-04-08 | Siemens Ag | Varistor material with high non linearity - made from zinc oxide with oxides of bismuth, antimony, chromium, cobalt and manganese |
| US4031498A (en) * | 1974-10-26 | 1977-06-21 | Kabushiki Kaisha Meidensha | Non-linear voltage-dependent resistor |
| US4077915A (en) * | 1975-09-18 | 1978-03-07 | Tdk Electronics Co., Ltd. | Non-linear resistor |
| US4042535A (en) * | 1975-09-25 | 1977-08-16 | General Electric Company | Metal oxide varistor with improved electrical properties |
-
1977
- 1977-08-05 DE DE2735484A patent/DE2735484C2/en not_active Expired
-
1978
- 1978-06-19 EP EP78100192A patent/EP0000864B1/en not_active Expired
- 1978-06-22 US US05/917,857 patent/US4186367A/en not_active Expired - Lifetime
- 1978-08-02 JP JP53094452A patent/JPS5928962B2/en not_active Expired
- 1978-08-02 CA CA000308575A patent/CA1117223A/en not_active Expired
- 1978-08-04 IT IT26492/78A patent/IT1097664B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| IT1097664B (en) | 1985-08-31 |
| JPS5928962B2 (en) | 1984-07-17 |
| JPS5429096A (en) | 1979-03-03 |
| DE2735484A1 (en) | 1979-02-15 |
| EP0000864A1 (en) | 1979-03-07 |
| US4186367A (en) | 1980-01-29 |
| CA1117223A (en) | 1982-01-26 |
| IT7826492A0 (en) | 1978-08-04 |
| DE2735484C2 (en) | 1984-06-07 |
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