JP2005206396A - Method of preparing glass composition, method of preparing resistor paste, method of manufacturing resistor and method of manufacturing electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the temperature coefficient of resistance (TCR) and withstand voltage characteristic (STOL) compatible in a resistor, for example, having high resistance of ≥10 kΩ/sq. <P>SOLUTION: The method of preparing the glass composition is carried out by melting an oxide mixed powder in a crucible and quenching the molten material to be vitrified. In such a case, when the melting temperature is expressed by T°C, an average cooling rate from T°C to (T-200)°C is expressed by A °C/sec and an average cooling rate from (T-200°C) to 100°C is expressed by B °C/sec, the relation between A and B is B>A, where A>10 and B>10<SP>3</SP>. The resultant glass composition is used for the resistor paste and a thick film resistor and in the resistor having ≥10 kΩ/sq resistance, the TCR characteristic is made compatible with the STOL characteristic. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a glass composition used for a resistor paste, and further relates to a method for manufacturing a resistor paste to which the glass composition is applied, a method for manufacturing a resistor, and a method for manufacturing an electronic component.

For example, a resistor paste is generally composed of a glass composition for adjusting a resistance value and imparting bonding properties, a conductive material, and an organic vehicle as main components, and after printing this on a substrate, By baking, a thick film resistor having a thickness of about 5 to 20 μm is formed. In this type of resistor paste (thick film resistor), usually, ruthenium oxide (RuO ₂ ), lead ruthenium oxide or the like is used as the conductive material, and lead oxide (PbO) glass or the like is used as the glass. It is used.

  In recent years, environmental issues have been actively discussed, and elimination of harmful substances such as lead from electronic components is being promoted. The resistor paste and the thick film resistor are no exception, and research is being conducted to make them lead-free.

  As one of the problems in making the resistor paste lead-free, there is a compatibility between temperature characteristics (TCR) and withstand voltage characteristics (STOL) particularly in a resistor paste having a high resistance (10 kΩ / □ or more). For example, when adjusting the TCR by adding a metal oxide, which has been used in conventional lead-based resistor pastes, to a lead-free composition as it is, changes in resistance due to voltage application are compared with the lead-based composition. As a result, it is difficult to achieve both TCR and STOL.

Under such circumstances, in a resistor paste mainly composed of a lead-free glass composition, a lead-free conductive material, and an organic vehicle, CaTiO ₃ or NiO is added as an additive, and temperature characteristics (TCR ) And withstand voltage characteristics (STOL) have been attempted (see, for example, Patent Document 1).

In Patent Document 1, it is preferable that the resistor paste contains, for example, CaTiO ₃ more than 0 vol%, 13 vol% or less, or NiO more than 0 vol%, 12 vol% or less, and further additives such as CuO, ZnO, MgO, etc. There is a description that it is preferable to add them at the same time, and as a result, lead suitable for obtaining a resistor having a low temperature characteristic (TCR) and a low withstand voltage characteristic (STOL) while having a high resistance value. It is said that it is possible to provide a free resistor paste.
JP 2003-197405 A

  However, as in the invention described in Patent Document 1, in a resistor formed using a resistor paste whose TCR characteristics are adjusted by adding a large amount of additives, a resistor paste having a conventional lead-based composition is used. The STOL characteristic tends to be lower than that in the case of the above. Therefore, for example, it is desired to further improve STOL characteristics in a state where an additive is not added in a large amount.

  Therefore, the present invention has been proposed in view of such a conventional situation. For example, in a resistor having a high resistance value of 10 kΩ / □ or more, both temperature characteristics (TCR) and withstand voltage characteristics (STOL) are achieved. It aims at providing the manufacturing method of the obtained glass composition. The present invention also provides a method of manufacturing a resistor paste having high resistance, excellent temperature characteristics (TCR) and withstand voltage characteristics (STOL), and excellent thermal stability, and manufacturing of a resistor using the resistor paste. It is an object of the present invention to provide a method and a method for manufacturing an electronic component.

  The present inventors have made various studies over a long period of time for the purpose of achieving both temperature characteristics (TCR) and withstand voltage characteristics (STOL) in thick film resistors. As a result, it came to the conclusion that it was realizable by devising the manufacturing method of the glass composition to be used.

  The present invention has been completed based on such findings. That is, the method for producing a glass composition according to the present invention is a method for producing a glass composition in which an oxide mixed powder is melted in a crucible, and the melt is rapidly cooled to vitrify. B> A when the average cooling rate from T ° C to (T-200) ° C is A ° C / sec and the average cooling rate from (T-200) ° C to 100 ° C is B ° C / sec. It is characterized by. Also, the method for producing a resistor paste of the present invention comprises melting an oxide mixed powder in a crucible, quenching the melt and vitrifying it to obtain a glass composition, and the glass composition and the conductive material are combined with an organic vehicle. The resistor paste is mixed with a melting point of T.degree. C., an average cooling rate from T.degree. C. to (T-200) .degree. C. is A.degree. C./second, and (T-200) .degree. When the average cooling rate from 1 to 100 ° C. is B ° C./second, B> A. Furthermore, the method for manufacturing a resistor and the method for manufacturing an electronic component according to the present invention include forming a resistor paste by applying the resistor paste on a substrate and firing the resistor paste by the above method. Features.

  In the process of producing the glass composition, by optimizing the temperature profile at the time of vitrification by rapid cooling, the distortion of the obtained glass is relaxed and stabilized. By using the glass composition thus obtained for the resistor paste (resistor), TCR characteristics and STOL characteristics are compatible in a high resistance region of 10 kΩ / □ or more.

  According to the method for producing a glass composition of the present invention, a glass composition capable of achieving both TCR characteristics and STOL characteristics can be provided, and this can be applied to a method for producing a resistor paste, a resistor, and an electronic component. Thus, it is possible to manufacture a resistor and an electronic component having a high resistance value and excellent in temperature characteristics (TCR) and withstand voltage characteristics (STOL).

  Hereinafter, the manufacturing method of the glass composition concerning this invention, a resistor paste, a resistor, and the manufacturing method of an electronic component are demonstrated.

First, the method for producing the glass composition of the present invention is basically carried out by following the usual production method. That is, an oxide mixed powder as a raw material is put in a crucible, heated to a melting temperature, and kept at the melting temperature for a certain time. Next, the melt in the crucible is poured into water or dropped on a cooling roll, and the melt is rapidly cooled to be vitrified. At this time, in the conventional method, sudden cooling is usually performed suddenly, and the temperature profile of the rapid cooling is as shown by a broken line in FIG. That is, in the conventional rapid cooling, the cooling rate is set to a steep slope that immediately exceeds 10 ³ ° C / second from the melting temperature.

  However, if the cooling rate is set to such a steep slope immediately after melting, the resulting glass composition remains strained, and when used as a glass material for a resistor paste, temperature characteristics (TCR) and withstand voltage characteristics (STOL) It becomes a factor to destabilize.

  Therefore, in the present invention, the temperature profile at the time of rapid cooling is reviewed, the cooling rate immediately after melting is slightly suppressed, and then the rapid cooling is performed at a predetermined cooling rate. Specifically, the melting temperature is T ° C, the average cooling rate from T ° C to (T-200) ° C is A ° C / sec, the average cooling rate from (T-200) ° C to 100 ° C is B ° C / sec. B> A. FIG. 1 shows a temperature profile (solid line) of rapid cooling in the present invention. In the present invention, in the initial stage immediately after melting (period indicated by A in the figure), the average cooling rate A is smaller than the predetermined rapid cooling rate (average cooling rate B in the period indicated by B in the figure) (inclination in the figure). Is small).

Here, the period A in which the average cooling rate is A is a period until the melting temperature becomes minus 200 (T−200) ° C. If the end point of this period A is lower than the melting temperature minus 200 ° C., the temperature before the rapid cooling becomes too low, and there is a possibility of hindering vitrification. Moreover, although each average cooling rate A and B can be arbitrarily set in the range which satisfies the said relationship, when considering vitrification, it is preferable that average cooling rate A shall be 10 degree-C / sec or more, and average cooling The speed B is preferably 10 ³ ° C / second.

  Any method can be used as long as such a temperature profile can be obtained. For example, after melting, the crucible is taken out from the furnace, allowed to cool for a predetermined period, and then poured into water. You just have to do it.

The target glass composition is, for example, a resistor paste or a thick film resistor glass material, and will be described in detail later. At least one selected from CaO, SrO, and BaO as a main modifying oxide component, and network formation Glass composition containing at least one selected from B ₂ O ₃ and SiO ₂ as an oxide component, and further containing at least one selected from ZrO, Al ₂ O ₃ , ZnO as another modified oxide component It is a thing.

  By preparing the glass composition by rapid cooling according to the above temperature profile, a stable glass composition with less distortion can be obtained. By using this for the resistor paste (resistor), the TCR characteristics and STOL characteristics can be obtained. It can be compatible.

In order to produce a resistor paste, a glass composition is prepared by the above-described method, and then mixed with an organic vehicle together with a conductive material and, if necessary, an additive. Here, the conductive material has a role of imparting conductivity to the thick film resistor as the structure by being dispersed in the glass as the insulator. As the conductive material, it is preferable to use a conductive material that does not substantially contain lead in terms of environmental protection. Here, considering the combination with the glass composition, RuO ₂ or Ru composite oxide is used. As the Ru composite oxide, at least one selected from CaRuO ₃ , SrRuO ₃ , BaRuO ₃ , and Bi ₂ Ru ₂ O ₇ is preferable.

  The content of the conductive material in the resistor paste is 9.4 wt% to 53.3 wt% when the total weight of the glass composition, the conductive material, and the additive is 100 wt%. Is preferred. When the content of the conductive material is less than the above range, the resistance value becomes too high, which may make it unsuitable for use as a resistor paste. On the contrary, if the content of the conductive material exceeds the above range, the binding of the conductive material by the glass composition becomes insufficient, and the reliability may be lowered.

  The composition of the glass composition is not particularly limited as long as it is produced by the above-described method. However, in the present invention, it is preferable to use a lead-free glass composition that does not substantially contain lead for environmental protection. . In the present invention, “substantially free of lead” means not containing lead exceeding the amount that cannot be said to be an impurity level, and the amount of impurity level (for example, the content in the glass composition). Is about 0.05% by weight or less). Lead may be contained in a trace amount as an inevitable impurity.

When the glass composition is a resistor, it has a role of binding the conductive material and the additive to the substrate in the resistor. The glass composition can be used by mixing a modified oxide component, a network-forming oxide component, or the like as a raw material. Examples of the main modifying oxide component include alkaline earth oxides, specifically, at least one selected from CaO, SrO, and BaO. Examples of the network forming oxide component include B ₂ O ₃ and SiO ₂ . In addition to the main modified oxide component, any other metal oxide can be used as another modified oxide component. Specific metal oxides, for example _{ZrO 2, Al 2 O 3,} ZnO, CuO, NiO, CoO, MnO, Cr 2 O 3, V 2 O 5, MgO, Li 2 O, Na 2 O, K 2 O , TiO ₂ , SnO ₂ , Y ₂ O ₃ , Fe ₂ O _3, etc., among which at least one selected from ZrO ₂ , Al ₂ O ₃ , and MnO is preferable.

  There is an optimum range for the content of each component in the glass composition. For example, if the content of the main modifying oxide component is too small, the reactivity with the conductive material is lowered and the TCR and STOL characteristics are deteriorated. There is a fear. On the other hand, when the content of the main modifying oxide component is too large, when a resistor is formed, excessive metal oxide may be deposited, which may deteriorate the characteristics and reliability. When the content of the network-forming oxide component is small, the softening point of the glass composition becomes high. Therefore, when a resistor is formed at a predetermined firing temperature, the resistor is not sufficiently sintered and the reliability is remarkably improved. May decrease. On the other hand, when the content of the network-forming oxide component is too large, the water resistance of the glass composition is lowered, and thus there is a possibility that the reliability when a resistor is used is significantly lowered. Moreover, when there is too little content of another modification oxide component, since the water resistance of a glass composition falls, there exists a possibility that the reliability when it may be set as a resistor may fall remarkably. On the other hand, when the content of other modified oxide components is too large, when a resistor is formed, excessive metal oxide may be deposited, which may deteriorate the characteristics and reliability.

  The content of the glass composition in the resistor paste is 47.7 wt% to 90.6 wt% when the total weight of the conductive material, the glass composition, and the additive is 100 wt%. preferable. When the content is small, the binding of the conductive material and the additive becomes insufficient, and the reliability may be significantly lowered. On the other hand, if the content of the glass composition exceeds the above range, the resistance value becomes too high, which may make it unsuitable for use as a resistor paste.

  In addition to the glass composition and the conductive material described above, the resistor paste may contain an additive for the purpose of adjusting characteristics. The content of the additive in the resistor paste is preferably 0 to 27.2% by weight when the total weight of the glass composition, the conductive material, and the additive is 100% by weight. It is more preferable to set it as weight%-27.2 weight%. When the content of the additive is small, it is difficult to sufficiently adjust the characteristics. On the other hand, when the content of the additive is too large, the binding of the conductive material and the additive becomes insufficient, and the reliability may be significantly reduced.

Any metal oxide can be used as the additive. Specifically, like _{MgO, TiO 2, SnO 2,} ZnO, CoO, CuO, NiO, MnO, Mn 3 O 4, Fe 2 O 3, Cr 2 O 3, Y 2 O 3, V 2 O 5 and the like It is done. Among these, CuO, NiO, and MgO, which are highly effective oxides as a TCR adjuster, are preferable. When there is too much content of each additive, there exists a possibility that a STOL characteristic may deteriorate.

  The organic vehicle has a role of kneading the glass composition, the conductive material, and the additive into a paste, and any of those used for this type of resistor paste can be used. An organic vehicle is prepared by dissolving a binder in an organic solvent. It does not specifically limit as a binder, For example, what is necessary is just to select suitably from various binders, such as an ethyl cellulose and polyvinyl butyral. The organic solvent is not limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, acetone, and toluene. Furthermore, in order to adjust the physical properties of the resistor paste, various additives such as a dispersant may be added.

  The organic vehicle compounding ratio is a ratio (W2 / W1) of the total weight (W1) of the glass composition, the conductive material, and the additive to the weight (W2) of the organic vehicle (0.25). -4 (W2: W1 = 1: 0.25 to 1: 4) is preferable. More preferably, the ratio (W2 / W1) is 0.5-2. If the ratio is outside the above range, a resistor paste having a viscosity suitable for forming a resistor on, for example, a substrate may not be obtained.

In order to form the resistor, the resistor paste containing the above-described components may be printed (applied) on the substrate by a method such as screen printing and fired at a temperature of about 850 ° C. As the substrate, a dielectric substrate such as an Al ₂ O ₃ substrate or a BaTiO ₃ substrate, a low-temperature fired ceramic substrate, an AlN substrate, or the like can be used. The substrate form may be any of a single layer substrate, a composite substrate, and a multilayer substrate. In the case of a multilayer substrate, the resistor may be formed on the surface or inside.

  In forming the resistor, a conductive pattern to be an electrode is usually formed on the substrate, and this conductive pattern is printed with a conductive paste containing an Ag-based highly conductive material containing Ag, Pt, Pd, or the like, for example. Can be formed. Further, a protective film such as a glass film may be formed on the surface of the formed resistor.

  The electronic component to which the resistor of the present invention can be applied is not particularly limited. For example, a single-layer or multi-layer circuit board, a resistor such as a chip resistor, an isolator element, a CR composite element, a module element, and a laminated layer Capacitors such as chip capacitors, inductors and the like can be mentioned, and the present invention can also be applied to electrode portions such as capacitors and inductors.

  Further, the conductive material of the present invention is not limited to the resistor paste or the conductive material of the resistor, but can be used as a conductive material for any application. For example, the conductive material of the present invention is directly included on a substrate. It is also possible to form a pattern and use it as an electrode or wiring.

  Hereinafter, specific examples to which the present invention is applied will be described based on experimental results. Needless to say, the present invention is not limited to the following examples.

<Preparation of glass composition>
B ₂ O ₃ , SiO ₂ , CaCO ₃ and ZrO ₂ were weighed in predetermined amounts, mixed in a ball mill, and then dried. The obtained powder was heated to 1300 ° C. at a rate of 5 ° C./min, held at that temperature for 1 hour, then rapidly cooled and vitrified. The obtained vitrified product was pulverized with a ball mill to obtain a glass composition powder. The composition of the produced glass composition is CaO: B ₂ O ₃ : SiO ₂ : ZrO ₂ = 34: 36: 25: 5 (mol%).

Here, Sample 1 (corresponding to a comparative example) was rapidly cooled from 1300 ° C. to 100 ° C. within 1 second. Accordingly, the average cooling rate is 10 ³ ° C / second or more for both periods A and B in FIG. On the other hand, Sample 2 (corresponding to the example) was allowed to cool to 1300 ° C. to about 1100 ° C. for 1 second, and then rapidly cooled to 100 ° C. within 1 second. The average cooling rate A in period A is approximately 20 ² ° C / second, and the average cooling rate B in period B is 10 ³ ° C / second or more.

CaCO ₃ powder and RuO ₂ powder were weighed to become CaRuO ₃ , mixed in a ball mill and dried. The obtained powder was heated to 1200 ° C. at a rate of 5 ° C./min, held at that temperature for 5 hours, and then cooled to room temperature at a rate of 5 ° C./min to obtain a CaRuO ₃ powder. The obtained conductive material was pulverized by a ball mill.

<Additives>
As an additive, CuO, NiO, MgO or the like was used.

<Preparation of organic vehicle>
Using ethyl cellulose as the binder and terpineol as the organic solvent, the binder was dissolved while heating and stirring the organic solvent to prepare an organic vehicle.

<Preparation of resistor paste>
The above-mentioned conductive material powder, glass composition powder, additive, and organic vehicle were weighed so as to have each composition, and kneaded with a three-roll mill to obtain a resistor paste. The ratio of the total weight of the conductive material powder, the glass composition powder and the additive powder to the weight of the organic vehicle is 1: 1 by weight so that the obtained resistor paste has a viscosity suitable for screen printing. A resistor paste was prepared by blending in the range of 0.25 to 1: 4.

<Fabrication of resistor>
On a 96% alumina substrate, the Ag—Pt conductor paste was screen printed in a predetermined shape and dried. The Ag ratio in the Ag-Pt conductor paste was 95% by weight, and the Pt ratio was 5% by weight. This alumina substrate was placed in a belt furnace and baked in a pattern of 1 hour from charging to discharging. The baking temperature at this time was 850 ° C., and the holding time at that temperature was 10 minutes.

  On the alumina substrate on which the conductor was formed in this manner, the resistor paste prepared previously was applied in a pattern of a predetermined shape (1 mm × 1 mm square shape) by screen printing and dried. Thereafter, the resistor paste was baked under the same conditions as the conductor baking to obtain a thick film resistor.

<Evaluation of resistor characteristics>
(1) Resistance value
Measured with Agilent Technologies product number 34401A. The average value of 24 samples was determined.

(2) TCR
The resistance value change rate when the temperature was changed to −55 ° C. and 125 ° C. was obtained based on the room temperature of 25 ° C. The average value of 10 samples. TCR (ppm / ° C) = [(R-55-R25) / R25 / 80] x resistance values of -55 ° C, 25 ° C, 125 ° C are R-55, R25, R125 (Ω / □) 1000000, or TCR (ppm / ° C.) = [(R125−R25) / R25 / 100] × 1000000. The larger value was taken as the TCR value.

(3) STOL (withstand voltage characteristics)
A test voltage was applied to the thick film resistor for 5 seconds, and the change rate of the resistance value before and after that was determined. The average value of 10 samples. Test voltage = 2.5 × rated voltage, rated voltage = √ (R / 8), and R is a resistance value (Ω / □). For resistors having a resistance value with the calculated test voltage exceeding 200V, the test voltage was 200V.

(4) Heat cycle test This is one of the reliability tests of resistors. The exposure of the resistor to −55 ° C. and 125 ° C. was taken as one cycle, and the resistance value variation ΔR was determined when 1000 cycles were repeated in total. It is preferable that ΔR (%) <± 1.0%.

<Evaluation results>
First, when the characteristics of a resistor using Sample 1 (corresponding to a comparative example) as a glass composition were evaluated, the resistance value was 1.807 MΩ, TCR-64 ppm, STOL-4.9%, and ΔR 1.2%. . On the other hand, in the resistor using Sample 2 (corresponding to Example) as the glass composition, the resistance value is 1.230 MΩ, TCR-60 ppm, STOL-3.9%, ΔR 0.3%, and the STOL value. Was improved by 20% or more, and ΔR was suppressed to an extremely small value.

It is a figure which shows the temperature profile of rapid cooling.

Claims (16)

A method for producing a glass composition comprising melting an oxide mixed powder in a crucible, quenching the melt, and vitrifying the mixture.
When the melting temperature is T ° C, the average cooling rate from T ° C to (T-200) ° C is A ° C / second, and the average cooling rate from (T-200) ° C to 100 ° C is B ° C / second, B> A, The manufacturing method of the glass composition characterized by the above-mentioned. The method for producing a glass composition according to claim 1, wherein A> 10 and B> 10 ³ .   The method for producing a glass composition according to claim 1 or 2, wherein after melting, the crucible is allowed to cool for a predetermined time and then the melt is quenched. The glass composition contains at least one selected from CaO, SrO, and BaO as a main modifying oxide component, and at least one selected from B ₂ O ₃ and SiO ₂ as a network forming oxide component. The method for producing a glass composition according to any one of claims 1 to 3, characterized in that: Method for producing the glass composition, other modifier oxide ingredient as ZrO, Al ₂ O _3, the glass composition according to claim 4, characterized in that it contains at least one selected from ZnO. A method for producing a resistor paste comprising melting an oxide mixed powder in a crucible, rapidly cooling the melt to vitrify to obtain a glass composition, and mixing the glass composition and the conductive material with an organic vehicle,
Upon the vitrification, the melting temperature is T ° C, the average cooling rate from T ° C to (T-200) ° C is A ° C / sec, the average cooling rate from (T-200) ° C to 100 ° C is B ° C / sec. And B> A, a method for producing a resistor paste. The method of manufacturing a resistor paste according to claim 6, wherein A> 10 and B> 10 ³ .   8. The method for producing a resistor paste according to claim 6, wherein after melting, the crucible is allowed to cool for a predetermined time and then the melt is quenched. The glass composition contains at least one selected from CaO, SrO, and BaO as a main modifying oxide component, and at least one selected from B ₂ O ₃ and SiO ₂ as a network forming oxide component. The method for producing a resistor paste according to claim 6, wherein the resistor paste is produced. The method for producing a resistor paste according to claim 9, wherein the glass composition contains at least one selected from ZrO, Al ₂ O ₃ , and ZnO as another modified oxide component. The method of manufacturing a resistor paste according to claim 6, wherein the conductive material is at least one of RuO ₂ and Ru composite oxide. The conductive _{material, RuO 2, CaRuO 3, SrRuO} 3, BaRuO 3, Bi 2 process according to claim 11, wherein the resistive paste, characterized in that at least one selected from Ru ₂ O _7.   13. The method of manufacturing a resistor paste according to claim 6, wherein at least one of NiO, CuO, and MgO is added and mixed as an additive.   The ratio of the total weight of the glass composition, the conductive material, and the additive to the weight of the organic vehicle is set to 1: 0.25 to 1: 4. The method for producing a resistor paste according to any one of the above.   A resistor is formed by forming a resistor paste by the method according to any one of claims 6 to 14, and applying the resistor paste onto a substrate and firing the resistor paste. Method.   A resistor paste is formed by the method according to any one of claims 6 to 14, and the resistor paste is applied on a substrate and baked to form a resistor. Method.

Images