JP2003257703A - Resistor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem about the fact that a lead-free material or a lead-free electronic component is required to be used at present for conserving the global environment, and it is difficult for paste used for forming a printing- type thick-film resistor to dispense with lead. <P>SOLUTION: An electrode where a lead-free bismuth glass is used as a binder and a resistor overlapping partially with the electrode are provided on the surface of a high-purity alumina board, and the resistor is formed of a ruthenium oxide and bismuth rutheniumate or a mixture of a ruthenium oxide, bismuth rutheniumate, and a lead-free bismuth binder glass and covered with a lead-free bismuth glass film for the formation of a lead-fully free printing-type thick-film resistor unit. In Figure, the high-purity alumina board, the silver electrode where the lead-free bismuth binder glass is used as a binder, the resistor of the lead- free bismuth binder glass, and the lead-free bismuth glass film covering the resistor for protection are represented by 1, 2, 3, and 4 respectively. The materials forming the above component elements are all kept free from lead as mentioned above, so that the printing-type thick-film resistor coping completely with environmental protection can be provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing type thick film resistor, in which all electrodes, resistors, and protective glass films for the purpose of protecting the resistors are made of lead-free material, and electrodes of resistors are formed. The present invention relates to a resistor in which the firing steps of resistor formation and protective glass film formation can be performed simultaneously.

2. Description of the Related Art A conventional printing type thick film resistor is composed of an electrode, a resistor and a resistor protective glass film on a heat resistant insulating substrate. A high-purity alumina substrate, an electrode paste, a resistor paste, and a protective glass paste are used as the respective materials, and a lead-based glass frit is used in any of these pastes. Further, ruthenium oxide (RuO ₂ ) and lead ruthenate (Pb ₂ RU ₂ O ₆ ) were mainly used as the resistance material of the resistor. Further, in the configuration of the printing type thick film resistor, printing, drying and firing are performed for each of the formation of the electrode, the formation of the resistance and the formation of the protective glass film, so that the number of steps is large and energy saving and cost reduction are also taken into consideration. Had challenges.

[Problems to be Solved by the Invention] Nowadays, as the global environment protection is being sought, energy saving and sustainable economic development are being promoted, the electronics field has reached a stage where steady improvement measures are required. The printed type thick film resistor, which is an electronic component, occupies a large specific weight quantitatively among the components used in electronic devices. An electrode paste, a resistance paste, and a protective glass paste are used for the electrodes of the printing type thick film resistor, the resistor, and the material of the coated glass film, respectively, and a lead-based glass frit is used for any of these pastes. Has been done. Moreover, ruthenium oxide (RuO ₂ ) and lead ruthenate (Pb ₂ R) are mainly used as the resistance material of the resistor.
U ₂ O ₆ ) has been used. On the other hand, lead-free materials and electronic components have been desired from the viewpoint of global environmental protection, and there has been a problem in making the lead-free paste used for printing type thick film resistors. On the other hand, in the configuration of the printing type thick film resistor, printing, drying and firing are performed for each of the electrode formation, the resistance formation and the protective glass film formation, so that the number of steps is large and energy saving and cost reduction are also taken into consideration. I had a problem. The present invention solves the above-mentioned conventional problems, and uses a lead-free paste for each of the electrode paste, the resistance paste, and the protective glass paste, and further, the firing process can be simplified and the resistor can contribute to the global environment. It is intended to provide.

Means for Solving the Problems In order to achieve the above object, the present invention has the following configurations. Claim 1 of the present invention
The invention described in, in particular, has a resistor on the surface of the heat-resistant insulating substrate, the electrode using a lead-free bismuth glass as a binder, and a resistor partially overlapping the electrode, wherein the resistor is ruthenium oxide or bismuth ruthenate or oxide. It is composed of a mixture of ruthenium and bismuth ruthenate and a lead-free bismuth-based binder glass, whereby a lead-free bismuth-based glass is used for the electrodes and the binder glass of the resistor, and the resistor does not contain lead element. Using ruthenium and bismuth ruthenate,
Further, since high-purity alumina is used for the heat-resistant insulating substrate, it is possible to obtain the effect of obtaining a completely lead-free resistor. In the invention according to claim 2 of the present invention, particularly, the main component of the lead-free bismuth-based binder glass is Si.
It has a structure of O ₂ , BaO, ZnO, Al ₂ O ₃ and Bi ₂ O ₃ , and thereby SiO ₂ and Al ₂
O ₃ is a skeleton material forming a glass network.
Further, BaO and ZnO are used for the role of adjusting the glass softening point to the firing temperature in the resistor manufacturing process and for stabilizing the glass. Bi ₂ O ₃ -containing glass is a resistance material bismuth ruthenate (Bi ₂ Ru ₂ O ₇ ).
An interdiffusion layer is formed at the interface with and the effect of stabilizing the electrical conduction of the resistor is obtained. In the invention according to claim 3 of the present invention, the conductive agent of the electrode using lead-free bismuth glass as a binder is gold, silver, platinum, palladium,
Alternatively, it has a constitution of being an alloy or a mixture of the above-mentioned metals, whereby the area resistance value is 50 mΩ or less by containing 60% or more and 90 or less of the respective metals in the weight% after electrode firing. It is possible to obtain a stable conductive electrode for resistance. In the invention according to claim 4 of the present invention, the resistor is made of lead-free SiO ₂ , BaO,
It has a structure of coating with a bismuth-based glass film containing ZnO, Al ₂ O ₃ and Bi ₂ O ₃ as main components, whereby the bismuth-based glass is excellent in acid resistance,
In addition, it is a glass similar to the lead-free bismuth-based glass of the resistor, and since the interface between the resistor and the protective glass film forms an interdiffusion layer during firing, strong adhesion is obtained and the resistor is completely sealed. It is possible to obtain a function and effect that the structure can contribute to improvement of reliability of the resistor and environmental protection.

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Hereinafter, the invention described in claims 1 to 4 of the present invention will be described using Embodiment 1. 1A is a plan view of a resistor according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line AA. FIG. 2 is a manufacturing process diagram of the resistor of the present invention, which is a comparison diagram of the conventional process and the new process. In FIG. 1, 1 is a high-purity alumina substrate (hereinafter referred to as an alumina substrate), 2 is a silver electrode of lead-free bismuth-based binder glass (described as a new electrode), and 3 is a resistor of lead-free bismuth-based binder glass. (Described as a new resistor) 4 is a lead-free bismuth-based glass film (described as a new glass film) coated to protect the resistor. The manufacturing process of the resistor of the present invention having the above structure will be described step by step with reference to FIG. First, in the first step of the conventional steps, the alumina substrate 1 is prepared. In the second step, electrode printing is performed on the alumina substrate 1 with a silver electrode paste of lead-free bismuth-based binder glass using a screen mask for electrodes. In the third step, the printed electrode is dried by touch at 100 ° C to 150 ° C. In the fourth step, the electrode that has been dried by touch is baked at 850 ° C. to form a new electrode 2. In the fifth step, a resistor paste of lead-free bismuth-based binder glass is printed using a resistor screen mask so that the new electrode 2 is partially overlapped. In the sixth step, the printed resistor is touch-dried in the same manner as the printed electrode. In the seventh step, the resistance-dried resistor is fired at 800 ° C. to form a new resistor 3. In the eighth step, lead-free bismuth glass paste is printed on the protective glass film so as to cover the entire surface of the new resistor 3 using a glass screen mask. In the ninth step, the printed protective glass film is touch-dried in the same manner as the printed electrode. In the tenth step, the finger-protected protective glass film is baked at 650 ° C. to form a new glass film 4, and the resistor of the present invention can be obtained. Next, the new process will be sequentially described with reference to FIG. However, the description is omitted when the conditions are the same as those in the conventional process. The preparation of the substrate in the first step, the electrode printing in the second step, and the touch-free drying in the third step are performed using the same material as the conventional step and by the same method. However, the electrode firing in the fourth step is deleted in the conventional step, and the resistance printing in the fourth step is performed in the new step. In this step, the lead-free bismuth-based binder glass is partially overlapped with the touch-dried electrode. The resistor paste is printed using a resistor screen mask. The touch drying in the fifth step is performed by the same method as the touch drying in the third step. However, in the conventional process,
The resistance firing of the process is deleted, and the process proceeds to the 6th process of the new process. In this process, the lead-free bismuth glass paste is protected by using a screen mask for glass so as to cover the entire surface of the touch-dried resistor. Perform glass film printing. The touch drying in the seventh step is performed by the same method as the touch drying in the third step. Simultaneous firing of the electrode, resistance, and protective glass film in the eighth step has not been performed in the first to seventh steps of the new step,
For the first time in this step, the electrode, the resistor and the protective glass film are simultaneously fired at 850 ° C. to obtain the resistor of the present invention. As described above, the resistor of the present invention is
It can be produced in both conventional and new processes.
However, in the new step, since the firing step is the last step and firing can be performed at the same time at the same time, two steps of electrode firing and resistance firing, which are required in the conventional steps, in the intermediate step can be reduced. Especially, since the firing process requires high temperature, the energy saving effect is great. Next, the characteristic values of the resistor of the present development manufactured by the conventional process and the new process of FIG. 2 using the lead-free bismuth glass binder are shown below. (1) Hereinafter, as a new electrode material, the main component is SiO ₂ 2
8%, BaO 31%, ZnO 6%, Al ₂ O ₃ 6
%, Bi ₂ O ₃ 24%, other 5% lead-free glass binder, and silver fine powder as a conductive material is 6% by weight.
When the electrode is formed by the conventional process of FIG. 2 with the electrode paste containing 0% to 90%, the sheet resistance value is 50 mΩ or less. The surface condition after firing was also good, and the adhesion strength with the alumina substrate was sufficient. It is a satisfactory electrode for printing thick film resistors. The conductive material used here is fine silver powder, but it has been separately confirmed that noble metals such as gold, platinum, palladium, or alloys or mixtures of the above metals will cause no problem if they are used in the same manner as described above. . (2) Hereinafter, using the electrode of (1), the content of Bi ₂ O ₃ in the lead-free bismuth-based glass binder in the new resistance material was changed to prepare a resistor of the present development. The main components of the lead-free bismuth glass binder are shown below. _{SiO 2 BaO ZnO Al 2 O 3} Bi 2 O 3 13% product 41% 31% 6% 6% Bi2O 3 21% product _{41 24 6 6 Bi 2 O 3} 25% product _{29 31 6 6 Bi 2 O 3} 30% product 25 28 7 7 The glass material for the protective glass film was the lead-free bismuth-based glass binder having a Bi ₂ O ₃ content of 25%. The conductive material was RuO ₂ alone, and RuO ₂ / bismuth-based binder glass was constant at 20/80. The resistance characteristics of the resistor of the present invention made by using the above materials are shown in Table 1 (a). From this result, the resistance value decreases as the Bi ₂ O ₃ content increases. This is R when firing
uO ₂ reacts with Bi ₂ O ₃ and Bi ₂ R
This is considered to be for forming u ₂ O ₇ . In addition, the new process has a higher resistance value. It is considered that this is because the thermal history of the conventional process is different from that of the new process. However, if the Bi ₂ O ₃ content is in the range of 13% to 30%, the stability of the resistance value,
It was confirmed that the surface condition of the resistor was good and that it was sufficiently satisfactory as a lead-free printing type thick film resistor. (3) Hereinafter, the electrode of (1) is used, and the bismuth-based glass binder in the new resistance material is Bi ₂ O _{3 of} (2).
The content is 25%, and the conductive material is Bi ₂ Ru ₂ O ₇
Only, the Bi ₂ Ru ₂ O ₇ / bismuth glass binder ratio was changed, and the resistor of the present invention was prepared using the new process of FIG. The resistance characteristics of the resistor of the present invention produced as described above are shown in Table 1 (b). From this result, the resistance value is Bi ₂ Ru in the bismuth glass binder.
_{If the 2} O ₇ content decreases, the resistance value increases, and Bi ₂ R
By changing the ratio of u ₂ O ₇ / bismuth glass binder, it becomes possible to secure a wide resistance value range. _The content of Bi 2 _Ru 2 _{O 7} 20% 50%
It was confirmed that the stability of the resistance value and the surface condition of the resistor were good in the range of 10 and the lead-free printing type thick film resistor was sufficiently satisfactory. (4) Hereinafter, the electrode of (1) above is used, and the glass binder in the new resistance material has a Bi ₂ O ₃ content of ₂ above (2).
5% and conductive materials are RuO ₂ and Bi ₂ Ru ₂ O ₇
The material of the present invention was used to change the ratio of RuO ₂ / Bi ₂ Ru ₂ O ₇ and the resistor of the present invention was manufactured using the new process of FIG. However, when RuO ₂ / Bi ₂ Ru ₂ O ₇ = R, R / bismuth-based glass binder = 30/7
It was fixed at 0. The resistance characteristics of the resistor of the present invention produced as described above are shown in Table 1 (c). From this result, the resistance value increases as the RuO ₂ ratio decreases. Further, in the resistor of the present invention, when the Ru metal content rate in the conductive material is calculated, RuO ₂ / Bi ₂ Ru ₂ O ₇ = 100.
/ 0 (RU metal content rate = 23%) 19Ω, RuO ₂
/ Bi ₂ Ru ₂ O ₇ = 20/80 (Ru metal content rate =
11%) is 58Ω, and the Ru metal content rate is about 1/2.
Even if the resistance value is reduced to 1, the resistance value is only extremely high from 19Ω to 58Ω, and when making a resistor with the same resistance value, Ru metal, which is a precious metal, is small, the material cost is low, and the environment is protected. It can also correspond to. Also, Ru
If the content of RuO _{2 in} O ₂ / Bi ₂ Ru ₂ O ₇ is 20% or more, the stability of the resistance value and the surface condition of the resistor are good, and the lead-free printing type thick film resistor is sufficiently satisfactory. It was confirmed that (5) Hereinafter, the electrode of (1) is used, and the bismuth-based glass binder in the new resistance material is Bi ₂ O _{3 of} (2).
The content is 25%, and the conductive materials are RuO ₂ and Bi _2.
RuO ₂ / Bi ₂ was used with a material mixed with Ru ₂ O _7.
The resistor of the present invention was produced by using the new process of FIG. 2 while keeping the ratio of Ru ₂ O ₇ = 50/50 (= R ₅₀ ) constant and changing the R ₅₀ / Bi glass ratio. The resistance characteristics of the resistor of the present invention produced as described above are shown in Table 1 (d).
Shown in. From this result, the resistance value increases as the Bi ₂ Ru ₂ O ₇ content in the Bi type glass binder decreases, and the R / Bi type glass ratio is changed to secure a wide resistance value range. It will be possible. It was also confirmed that the stability of the resistance value and the surface condition of the resistor were good, and the lead-free printing type thick film resistor was sufficiently satisfactory. (6) Hereinafter, the electrode of (1) is used, and the bismuth-based glass binder in the new resistance material is Bi ₂ O _{3 of} (2).
Those content of 25%, the conductive material using only RuO _2, RuO ₂ / bismuth binder glass = 20/8
It was set to 0. The new glass film material has a Bi ₂ O ₃ content of 13%, which is the same as the composition of the bismuth-based glass binder in (2) above.
Four kinds of changes were made in the range of -30%. Using each of the above materials, the resistor of the present invention was produced in the new process of FIG. Table 1 (e) shows the resistance characteristics, the acid resistance test, and the appearance determination result of the resistor of the present invention produced as described above.
From this result, the resistance value becomes lower as the Bi ₂ O ₃ content in the new glass film increases. This is B in the binder glass
It is considered that i ₂ O ₃ and RuO _{2 of the} conductive material cause a thermal reaction at the contact interface to form an interdiffusion layer, and a small amount of Bi ₂ Ru ₂ O ₇ is produced to affect the resistance value.
The acid resistance test was carried out by placing the resistor in a 5% sulfuric acid solution at 50 ° C.
It is a method of examining the change in resistance value after leaving it for a while. It is said that there is no problem in the performance of the resistor if the change in the resistance value is within ± 5%, but in particular, the Bi ₂ O ₃ content is 25% to
The resistance change rate is low at 34%. This shows that the bismuth glass of the new glass film has excellent acid resistance. Further, the appearance judgment (visual observation) of the glass surface after the acid resistance test is not in any state in which it causes a problem, but it is particularly excellent at 25% to 34%. Thus, by coating the surface of the new resistor with the lead-free bismuth-based glass having excellent acid resistance, the reliability of the resistor of the present invention can be improved, and as a lead-free printing type thick film resistor, It was confirmed to be sufficiently satisfactory.

[Table 1]

As described above, according to the present invention, the resistor of the present invention uses high-purity alumina for the substrate, and the new electrode, new resistor and new glass film all use the lead-free bismuth-based glass binder. Therefore, it is configured as a completely lead-excluded type resistor, and the electrode, the resistor, and the glass film can be simultaneously fired at the same time, and an effect corresponding to environmental protection can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view (a) and a cross-sectional view (b) taken along line AA of a resistor according to the present invention.

FIG. 2 is a manufacturing process diagram of a resistor according to the present invention, which is a comparison diagram of a conventional process and a new process.

[Explanation of symbols]

1, high-purity alumina substrate 2 lead-free bismuth-based binder glass silver electrode 3 lead-free bismuth-based binder glass resistor 4 lead-free bismuth glass film coated to protect the resistor

Continued front page    (72) Inventor Masao Iwasaki             337 26 Kashiwara, Sayama City, Saitama Prefecture Kojima Chemical             Within the corporation F-term (reference) 5E033 AA11 AA18 AA22 BA01 BB02                       BB06 BC01 BD01 BE01 BG02                       BH01

Claims (4)

[Claims] 1. A surface of a heat-resistant insulating substrate is provided with an electrode using a lead-free bismuth glass as a binder and a resistor partially overlapping the electrode, the resistor being ruthenium oxide, bismuth ruthenate, or ruthenium oxide. A resistor comprising a mixture of bismuth ruthenate and a lead-free bismuth-based binder glass. 2. A lead-free bismuth-based binder glass whose main components are SiO ₂ , BaO, ZnO, Al ₂ O ₃ and B.
The resistor according to claim 1, wherein the resistor is i ₂ O ₃ . 3. The resistor according to claim 1, wherein the conductive agent of the electrode using the lead-free bismuth glass as a binder is gold, silver, platinum, palladium, or an alloy or mixture of the metals. 4. The lead according to claim 1, wherein the resistor is lead-free SiO ₂ , BaO, ZnO, Al ₂ O ₃ and Bi ₂ O _3.
A resistor characterized by being coated with a bismuth-based glass film containing as a main component.