JP4236021B2 - Electronic component having humidity detection function and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a humidity sensor, an electronic component having a humidity detection function, such as a composite component including a humidity sensor, and a method for manufacturing the same, and in particular, an electrode conductor is formed on an element main surface with high accuracy using a photosensitive conductive material. The present invention relates to an electronic component having a humidity detection function and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, a polymer type humidity sensor with a moisture sensitive film containing dissociated ions on a pair of microelectrode gaps on the surface of an insulating substrate has a wide measuring range and can be produced at a relatively low cost. Is expanding. Under such circumstances, requirements for humidity measurement on the low-humidity side, which is relatively weak with polymer-type humidity sensors, and accuracy and variations related to product humidity are becoming very strict.
[0003]
In addition, with the miniaturization of products that incorporate humidity sensors, the size of the humidity sensor body is also required to be reduced. As a result, the conductor pattern in the humidity sensor is required to be both miniaturized and highly accurate. Yes. For example, recently, miniaturized portable temperature and humidity measuring instruments, humidity sensors used in storage for low-temperature and low-humidity management, and further as humidity sensors for food and medical fields, etc., further miniaturization and higher accuracy Has been demanded. In particular, the electrode portion is desired to stably produce a high-precision fine pattern in the unit of μm with high yield and high accuracy, and at the same time, free ions (for example, halogens) existing in a polymer film as a moisture-sensitive film are desired. There is a demand for a highly reliable electrode structure with little influence on ions.
[0004]
Regarding electrode pattern accuracy, the pattern pitch of currently available humidity sensors has a size of 250 μm to 1000 μm, but it is expected that it will not be compatible with future miniaturization and high accuracy. Is required to be 30 μm to 50 μm or less.
[0005]
In addition, the mounting pattern that is the mounting part of the humidity sensor, the electrode of the mounting part, etc. are required to be higher in strength and more reliable due to downsizing, and moreover, due to recent lead-free, There is a tendency for the soldering temperature to increase, and there is also a need for a high heat resistance electrode that can withstand that.
[0006]
As a method of forming an electrode conductor on the surface of an insulating substrate, a screen printing method (thick film printing method) using a conductive paste is generally used because vacuum deposition and the like have a thin conductor film thickness and poor productivity. A silver paste, a gold paste, and further a ruthenium oxide paste is printed on a ceramic to form a conductor pattern, and then a drying process is performed to sinter the conductor pattern at a temperature of about 450 ° C. to 1000 ° C. A conductor is formed.
[0007]
FIG. 11 shows a manufacturing process of a humidity sensor using a screen printing method. First, on the insulating substrate 1 such as alumina shown in FIG. 11A, the terminal connecting electrode conductor 2 is printed with a conductive paste such as silver or silver palladium alloy as shown in FIG. Next, as shown in FIG. 11C, a pair of comb-shaped electrode conductor portions 3 facing each other with a minute gap is printed with a conductive paste of ruthenium oxide, and these conductive pastes are baked at a predetermined temperature and baked on the insulating substrate 1. Thereafter, a moisture sensitive film 4 which is a polymer film containing free ions such as halogen ions as shown in FIG. 11 (D) is provided on the pair of comb-shaped electrode conductor portions 3, and lead terminals as shown in FIG. 11 (E). 5 is soldered to the terminal connecting electrode conductor 2.
[0008]
In the actual mass production process, as shown in FIG. 12, the processes from FIGS. 11A to 11D are performed on a large number of sections on the collective substrate 10 to simultaneously produce humidity sensors. At that time, a space as shown by the hatched portion S is provided between adjacent elements in consideration of the positional deviation of the conductor pattern. Note that the comb-shaped electrode conductor portion 3 is not perpendicular to both sides as shown in the enlarged cross section of FIG.
[0009]
[Problems to be solved by the invention]
By the way, according to the above screen printing method, (1) screen position accuracy, (2) jig position accuracy, (3) paste bleeding, (4) print fading, (5) screen deterioration, 6 ▼ In order to form a fine conductor pattern with high accuracy and stability, such as deterioration of the squeegee, there are a number of factors causing dimensional variations. This influence causes the final humidity characteristics to vary among individual products, resulting in tolerances. It has become a big product.
[0010]
In particular, when a conductor pattern is formed by printing, the conductor pattern accuracy deteriorates due to the stretch of the screen that occurs due to repeated printing, the dimensional accuracy of the gap between the conductor patterns deteriorates, and further, the conductor pattern The deterioration of the linearity of the product itself had a great influence on the variation in product characteristics.
[0011]
Conventionally, in order to prevent this influence, a space around the conductor pattern that takes into account the deterioration of printing accuracy has been secured, or the gap between the electrodes has been made large by taking into account the deterioration and poorness of the electrode shape in advance. Was. For example, in the conventional manufacturing method shown in FIG. 11, the terminal connection electrode conductor portion 2 for soldering is formed of silver or the like, and the ruthenium oxide comb-shaped electrode conductor portion 3 is formed thereon. 12 and the position of the comb-shaped electrode portion 3 is shifted. Therefore, when a large number of products are printed at once on the collective substrate, a space around the conductor pattern as shown by the shaded portion S in FIG. Is provided.
[0012]
Further, the linearity of the conductor pattern is poor, and the cross-sectional shape of the comb-shaped electrode conductor portion 3 is also an irregular shape as shown in the enlarged cross section in FIG. 12, so that the shape of the moisture-sensitive film formed around it varies. The movement distance of dissociated ions such as halogen ions in various polymer materials varied and affected the accuracy of characteristics. In order to avoid this, if the gap between the electrodes is made large, ions can no longer move on the low humidity side, and as a result, the electric resistance value becomes large (for example, 100 MΩ or more) and measurement cannot be performed. I was sorry.
[0013]
On the other hand, in the field of wiring boards and plasma displays, recently there is a limit to the miniaturization of the above screen printing, so the use of photosensitive conductive paste (conductive paste having photosensitivity) is also being studied. In particular, a measure for improving the fluidity of the photosensitive conductive paste (Japanese Patent Laid-Open No. 10-112216) has been devised for the defect that a mesh mark causes a pinhole defect by screen printing. In this case, it is necessary to ensure sufficient corrosion resistance against halogen ions, to form a conductor pattern on the soldered portion where solder is easy to attach, and to a portion perpendicular to light (especially , Through-holes with large aspect ratios), ensuring the film thickness of pattern parts on module products that are mixed with other components, etc. Thickness comparable to the non-photosensitive conductive paste which is commercially available (conductive paste having no photosensitivity), items that have yet to still resolve such cheap like cost has not been obtained is present often.
[0014]
JP-A-8-186005 discloses a structure using a photosensitive ruthenium paste as a resistor.
[0015]
The first object of the present invention is not only to improve the conductor pattern printing accuracy, which has been a problem in the prior art, but also to have a predetermined film thickness suitable for the place where the electronic component having a humidity detection function is used, and the conductor pattern and electrode conductor. In addition, an electronic component having a humidity detection function capable of forming an electrode conductor even in a portion having a high aspect ratio and a method for manufacturing the same are provided.
[0016]
The second object of the present invention is to improve the accuracy by stabilizing the position accuracy of the conductor pattern, the accuracy of the line width, and the pattern shape, thereby greatly reducing the variation in the final product characteristics. An object of the present invention is to provide an electronic component having a humidity detection function capable of realizing a product with extremely small variation in characteristics and excellent in reliability, and a manufacturing method thereof.
[0017]
The third object of the present invention is to appropriately use a photosensitive conductive paste and a non-photosensitive conductive paste. For example, the photosensitive conductive paste is used as an electrode conductor portion for humidity detection, and the electrode conductor portion requiring soldering is used. For example, a non-photosensitive conductive paste is used to provide a conductive pattern with a high pattern accuracy, an electrode conductor portion that could not be achieved in the past, and an electrode conductor portion with a film thickness that can withstand soldering etc. An object of the present invention is to provide an electronic component having a humidity detection function that can be formed and a method for manufacturing the same.
[0018]
Other objects and novel features of the present invention will be clarified in embodiments described later.
[0019]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1 of the present application has a humidity detection function in which a pair of electrode conductors are formed on an insulating substrate so as to face each other with a gap, and a moisture sensitive film is provided in the gap. In electronic components,
  The moisture sensitive film is composed of a polymer film containing dissociative ions,
  The electrode conductor has a multilayer structure, the lowermost layer is made of a photosensitive conductive material, and at least the upper part of the electrode conductor has corrosion resistance to the moisture sensitive film.It is characterized by that.
[0023]
  Claim of this application2The invention of claim1The gap between the pair of electrode conductors is 20 to 100 μm, and the film thickness of each electrode conductor in the gap constituting portion is 3 to 20 μm.
[0024]
  Claim of this application3The invention of claim1 or 2In the present invention, at least a part of the electrode conductor is made of ruthenium, a ruthenium compound, gold, or a gold compound.
[0025]
  Claim of this application4The invention of4. The electrode conductor according to claim 1, wherein the electrode conductor is formed on the insulating substrate.Conductor pattern formed by exposing and developing photosensitive conductive paste on the main surfaceHaveIt has an electrode conductor portion and an electrode conductor portion formed of a non-photosensitive conductive paste, and at least a part of both electrode conductor portions overlap each other to constitute an electrically conductive electrode conductor. It is a feature.
  The invention of claim 5 of the present application is that in claim 4, the electrode conductor portion formed of the non-photosensitive conductive paste forms an end face electrode on the end face of the insulating substrate as at least a part of the electrode conductor. It is a feature.
[0026]
  Claim of this application6The invention is an electronic component having a humidity detection function in which an electrode conductor is formed across the main surface of the element and the other surface in contact with the main surface.
  Conductor pattern formed by exposing and developing a photosensitive conductive paste on the main surfaceHaveAn electrode conductor portion and an electrode conductor portion formed of a non-photosensitive conductive paste on the other surface, and at least a part of both electrode conductor portions in the vicinity of a portion where the main surface and the other surface are in contact with each other. It is characterized in that the electrode conductors are overlapped and electrically conducted.
[0027]
  Claim of this application7The invention of claim6The electrode conductor portion formed of the non-photosensitive conductive paste is characterized in that an end face electrode is formed on the end face of the element as at least a part of the electrode conductor.
[0028]
  Claim of this application8The invention of claim6 or 7The element has a connection surface connecting the main surface and the other surface at a portion where the main surface and the other surface are in contact, and is formed by exposing and developing the photosensitive conductive paste. A conductor pattern extends from the main surface to the connection surface to form an electrode conductor portion.
[0029]
  Claim of this application9According to the invention, an electrode conductorAnd moisture sensitive filmIn the manufacturing method of an electronic component having a humidity detection function formed,
  Exposure and development of photosensitive conductive paste on the main surfaceA pair of conductor patterns facing each other through a gapForming an electrode conductor portion;
  Forming an electrode conductor portion with a non-photosensitive conductive paste;
  Providing the moisture sensitive film,
  Arrange both electrode conductors on the surface of the device so that at least part of both electrode conductors overlap.And
  A metal plating film having corrosion resistance to the moisture sensitive film is formed at least on the electrode conductor portion covered with the moisture sensitive film, and then a moisture sensitive film is provided in the gap.It is characterized by that.
[0030]
  Claim of this application10In the method of manufacturing an electronic component having a humidity detection function in which an electrode conductor is formed across the main surface of the element and the other surface in contact with the main surface,
  Forming an electrode conductor portion with a non-photosensitive conductive paste on the other surface;
  A step of exposing and developing a photosensitive conductive paste on the main surface to form an electrode conductor portion comprising a conductor pattern;
  Both electrode conductor portions are arranged on the main surface and the other surface so that at least a part of both electrode conductor portions overlap each other.
[0031]
  Claim of this application11The invention of claim10The element has a connection surface connecting the main surface and the other surface at a portion where the main surface and the other surface are in contact, and the electrode conductor portion formed of the non-photosensitive conductive paste formed on the other surface is While extending to a connection surface, the electrode conductor part by the photosensitive electrically conductive paste formed in the said main surface is also extended to the said connection surface.
[0032]
  Claim of this application12The invention of claim10In this case, the electrode conductor portion made of the photosensitive conductive paste formed on the main surface overlaps the surface of the electrode conductor portion made of the non-photosensitive conductive paste formed on the other surface, and the photosensitive conductive paste is exposed and developed to form a conductor. A pattern is formed to form an electrode conductor straddling the main surface and the other surface.
[0033]
  Claim of this application13The invention of claim10, 11 or 12A pair of electrode conductor portions are formed so as to face each other through a gap with a conductive pattern obtained by exposing and developing the photosensitive conductive paste, and a metal plating film is formed on at least an upper layer of the electrode conductor portion covered with a moisture sensitive film. After the formation, a moisture sensitive film is provided in the gap.
[0034]
  The invention of claim 14 of the present application claims9, 10, 11, 12, or 13In the above, at least a part of the electrode conductor portion formed of the conductor pattern formed by exposing and developing the photosensitive conductive paste is overlapped with the electrode conductor portion formed of the non-photosensitive conductive paste and fired. It is characterized by.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an electronic component having a humidity detection function and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.
[0036]
A first embodiment of an electronic component having a humidity detection function and a manufacturing method thereof according to the present invention will be described with reference to FIGS. Here, when a humidity sensor is manufactured as an electronic component having a humidity detection function, a pair of comb-shaped electrode conductor portions covered with a moisture-sensitive film is configured using a photosensitive conductive material.
[0037]
In FIG. 1, in the non-photosensitive conductive paste coating step # 1, the non-photosensitive conductive paste is printed on the main surface of an insulating substrate 20 such as alumina by pattern printing with a screen printer or the like as shown in FIG. An attaching electrode conductor portion 21 (which will be a lead terminal connecting electrode conductor portion in this example) is formed and dried at 80 ° C. for 10 minutes in the drying step # 2. Since the positional accuracy of the soldering electrode conductor portion 21 does not cause a problem, a general screen printing method may be used.
[0038]
Next, in the photosensitive conductive paste application step # 3, the photosensitive conductive paste 22 is applied to the insulating substrate 20 so as to at least partially overlap the electrode conductor portion 21 of the non-photosensitive conductive paste as shown in FIG. It is applied to a predetermined range (most or all) of the main surface, and is dried at 80 ° C. for 20 minutes in the drying step # 4.
[0039]
In the exposure and development process # 5 (photolithography process), a predetermined pattern is applied to the photosensitive conductive paste 22 by an exposure light source to 200 to 3000 mJ / cm.²Then, unnecessary portions of the photosensitive conductive paste are removed by a development process. Development is performed by spraying or dipping at 20 ° C. to 50 ° C. with an alkali solution such as sodium carbonate, potassium carbonate, calcium hydroxide, or sodium hydroxide. Specifically, 0.4% Na at 30 ° C. with an ordinary conveyor or spray type developing machine.₂CO₃For example, by spraying at a spray pressure of 10 to 20 psi. By such development processing, a comb-shaped electrode conductor portion 23 is formed by patterning the photosensitive conductive paste 22 into a comb shape as shown in FIG. A pair of the comb-shaped electrode conductor portions 23 are formed so as to face each other with a minute gap, and are electrode conductor portions for humidity detection to be covered with a moisture-sensitive film.
[0040]
As shown in FIG. 2 (A), the pair of comb-shaped electrode conductor portions 23 has a stable shape because the side of the cross-sectional shape of the pair of comb-shaped electrode conductor portions 23 is vertical as well as the pattern bleeding and the variation in width are small. FIG. 2B shows a cross-sectional shape of a comb-shaped electrode conductor portion patterned with a conventional non-photosensitive conductive paste, and the side surface is not vertical and the shape is not stable.
[0041]
Examples of the exposure include visible light, near ultraviolet light, ultraviolet light, electron beam, X-ray, and laser light. Among these, ultraviolet light is preferable, and the light source thereof is, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, or an ultra-violet light. High pressure mercury lamp, halogen lamp sterilization lamp, etc. can be used. Among these, an ultra high pressure mercury lamp is particularly preferable. In addition, a developing process that does not affect the non-photosensitive conductive paste is selected.
[0042]
In order to dry the substrate 20 after applying the paste, after drying for 5 minutes at 80 ° C. and removing moisture, the electrode conductor portion 21 for soldering with the non-photosensitive conductive paste and the non-photosensitive conductive paste in the baking step # 6 Comb-shaped electrode conductor portion 23 made of photosensitive conductive paste is subjected to main firing for 1 hour (however, at peak time, temperature is 850 ° C. for 10 minutes), and by simultaneous firing, electrode conductor portion 21 and electrode conductor portion 23 overlap each other. An electrically conductive electrode conductor is obtained on the insulating substrate 20. Here, as shown in FIG. 3A, firing is performed in a connection state in which a part of the comb-shaped electrode conductor portion 23 overlaps the electrode conductor portion 21 for soldering. The simultaneous firing is advantageous in reducing the number of steps, but of course, the conductor portions may be fired separately.
[0043]
When the electrode conductor portions 21 and 23 on the insulating substrate 20 are baked, the moisture sensitive film 25 is applied so as to cover the pair of comb-shaped electrode conductor portions 23 in the moisture sensitive film application step # 7 as shown in FIG. And dried at a temperature of room temperature to about 120 ° C. Here, as shown in FIG. 2A, the moisture sensitive film 25 enters between the minute gaps G between the pair of comb-shaped electrode conductor portions 23, and preferably also covers the upper surface of the electrode conductor portion 23. Is formed. The moisture sensitive film 25 is composed of a polymer film containing dissociative ions such as halogen ions.
[0044]
As described with reference to FIG. 2A, the pair of comb-shaped electrode conductor portions 23 have less pattern bleeding and variation in width, and the cross-sectional side surface is also vertical, so that the shape is stable. The variation in the way of attaching 25 can be reduced, and the humidity detection characteristic can be stabilized. FIG. 2B shows a cross-sectional shape of a comb-shaped electrode conductor portion patterned with a conventional non-photosensitive conductive paste, and the side surface is not vertical and the shape is not stable, resulting in a moisture sensitive film. Variations will also occur in the way of attaching, and the characteristics will not be stable.
[0045]
When a humidity sensor having a lead terminal structure is formed after the moisture sensitive film 25 is formed, the lead terminal 26 is soldered to the soldering electrode conductor portion 21 as shown in FIG.
[0046]
In addition, ruthenium, a ruthenium compound (for example, ruthenium oxide, etc.) can be suitably used as the conductive material of the photosensitive conductive paste used for the electrode conductor portion 23 of the comb pattern, and other glass frit and photosensitive resin (monomer, oligomer). Or polymer), photopolymerization initiator, and sensitizer, and in some cases, a thermal polymerization inhibitor, an antioxidant, and a thickener may be added as necessary.
[0047]
By using a photosensitive conductive paste capable of forming a precise and fine pattern for the electrode portion for humidity detection, the gap G between the pair of comb-shaped electrode conductor portions 23 can be about 20 to 100 μm. Moreover, it is desirable that the film thickness of each electrode conductor portion in the gap constituting portion is 3 to 20 μm. If the gap is less than 20 μm, there is a risk of short circuit, and an interval exceeding 100 μm is easy to produce, but the advantage of adopting a photolithography process such as exposure and development of the photosensitive conductive paste is reduced. Further, if the film thickness in the gap constituting part of the comb-shaped electrode conductor portion 23 is less than 3 μm, there is a risk of occurrence of pinholes and comb-shaped patterns, and if the film thickness exceeds 20 μm, the exposure and development process of the photosensitive conductive paste Formation becomes troublesome. Moreover, even if the use as a humidity sensor is considered, it is not necessarily required that the film thickness exceeds 20 μm.
[0048]
In addition, the application | coating process of photosensitive electrically conductive paste can be performed by screen printing etc. similarly to the case of application | coating of a non-photosensitive electrically conductive paste.
[0049]
Since the electrode conductor portion 21 for soldering uses a non-photosensitive conductive paste, it has sufficient solder wettability and an electrode as an electrode portion that requires solderability and solder heat resistance like a normal chip component. The thickness can be increased, and a highly reliable electrode conductor portion can be obtained. As a result, even if soldering is performed using high-temperature solder that is lead-free, disconnection due to electrode biting does not occur.
[0050]
As described above, according to the first embodiment, the advantages of the electrode conductor portion by the non-photosensitive conductive paste and the advantages of the electrode conductor portion by the photosensitive conductive paste are combined, which is a conventional problem. In addition to increasing the pattern accuracy, it is possible to produce an electronic component having a humidity detection function in which an electrode conductor having a predetermined film thickness and pattern suitable for the place of use is formed. Specific effects are listed below.
[0051]
(1) In the production method using a photosensitive conductive paste, the conductive paste does not need to be printed with high accuracy and may be applied to the entire pattern forming surface. In addition, since the photosensitive conductive paste is exposed using a mask during pattern formation, it is not necessary to apply a large pressure to the printing mask (screen) as in the prior art. Accordingly, the pattern accuracy deteriorates due to deterioration of the screen. There is no need to worry about.
[0052]
(2) Since the exposure and development steps are performed, the pattern itself has high dimensional accuracy, there is no distortion of the pattern due to paste bleeding, and there is almost no variation in the pattern width. Therefore, in the case of a humidity sensor, by reducing the gap between the patterns of the pair of comb-shaped electrode conductor portions 23 that are the electrode conductor portions for humidity detection, that is, the gap G, the halogen ions in the polymer material can be reduced even on the low humidity side. Dissociated ions can be sufficiently detected as electrical resistance, and high sensitivity can be achieved. Further, since the comb-shaped electrode can be formed with 1/5 or less of the conventional size, the product itself can be downsized.
[0053]
(3) The comb-shaped electrode conductor portion 23 formed of the photosensitive conductive paste has not only bleeding and variations in the width of the pattern, but also the side surface of the cross-sectional shape is vertical and the shape is stable. Variations in attachment can also be reduced. Therefore, a product with little variation can be obtained. In the conventional pattern formation by screen printing, the side surfaces do not become vertical and the shape is not stable, and as a result, variations occur in how the moisture sensitive film is attached.
[0054]
(4) Furthermore, if the comb-shaped electrode conductor portion 23 is formed of a photosensitive conductive paste using ruthenium or a ruthenium compound that is relatively inexpensive as compared with gold (Au) as a conductive material, a sensitivity that includes halogen ions as dissociated ions. Since the wet film 25 has corrosion resistance, a process such as plating is not required to ensure the corrosion resistance, and the manufacturing process can be simplified. Also, when ruthenium oxide paste is used as the photosensitive conductive paste, since the paste is black, there is no light scattering compared to other metal particles, and light transmittance is higher than that of metal, so pattern formation with higher accuracy can be achieved. Is possible.
[0055]
(5) By eliminating the need for plating to ensure corrosion resistance, not only does the cost increase due to plating, but also a phenomenon called plating elongation, which is a problem for fine patterns (next to fine patterns and narrow pitch patterns). It is possible to solve the problem of short-circuit failure due to a phenomenon in which they are short-circuited by the lateral growth of the plating.
[0056]
(6) Since the non-photosensitive conductive paste is used for the electrode conductor portion 21 for soldering, a high-temperature solder that can be formed with a sufficient film thickness using a material having good conductivity and is lead-free. Even if soldering is performed using, the wire breakage due to electrode biting does not occur.
[0057]
(7) Further, it is not necessary to directly solder the comb-shaped electrode conductor portion 23 with the photosensitive conductive paste, and it is not necessary to apply the photosensitive conductive paste to the thick film more than necessary, and the pattern accuracy can be further improved.
[0058]
In the first embodiment, as shown in FIG. 3A, after applying the electrode conductor portion 21 for soldering with the non-photosensitive conductive paste on the insulating substrate 20, the comb-shaped electrode conductor with the photosensitive conductive paste is used. The part 23 is patterned, but the electrode conductor part 21 for soldering with the non-photosensitive conductive paste is applied in a predetermined pattern after the pattern formation of the comb-shaped electrode conductor part 23 with the photosensitive conductive paste as shown in FIG. But it doesn't matter. In this case, since the non-photosensitive paste can be applied after patterning first, the non-photosensitive conductive paste is applied to the developer (Na₂CO₃Solution).
[0059]
FIG. 4 shows a second embodiment of the present invention, and a soldering terminal electrode straddling the main surface and side surfaces of the insulating substrate 20 when a humidity sensor as an electronic component having a humidity detecting function is manufactured. A conductor portion 31 is formed.
[0060]
4, in the non-photosensitive conductive paste application step # 11, as shown in FIG. 4A, the non-photosensitive conductive paste is applied to the main surface and the end surface (side surface) of the insulating substrate 20 such as alumina by a screen printer or the like. Pattern printing is performed to form the terminal electrode conductor portion 31 for soldering, and drying is performed at 80 ° C. for 10 minutes in the drying step # 12. The terminal electrode conductor portion 31 may be provided so as to straddle the back surface of the substrate.
[0061]
Next, in the photosensitive conductive paste application step # 13, the photosensitive conductive paste 22 is applied to the insulating substrate 20 so as to at least partially overlap the electrode conductor portion 21 of the non-photosensitive conductive paste as shown in FIG. It is applied to a predetermined range (most or all) of the main surface, and is dried at 80 ° C. for 20 minutes in the drying step # 14.
[0062]
In the exposure and development process # 15 (photolithography process), the photosensitive conductive paste 22 is subjected to a predetermined exposure with an exposure light source in a predetermined pattern, and then an unnecessary portion of the photosensitive conductive paste is removed by a development process. By such development processing, a comb-shaped electrode conductor portion 23 is formed by patterning the photosensitive conductive paste 22 into a comb shape as shown in FIG. A pair of the comb-shaped electrode conductor portions 23 are formed on the main surface of the substrate so as to be opposed to each other with a minute gap, and are electrode conductor portions for humidity detection to be covered with a moisture sensitive film.
[0063]
In order to dry the board | substrate 20 after paste application | coating, after drying for 5 minutes at 80 degreeC and removing a water | moisture content, the terminal electrode conductor part 31 and the photosensitive property by non-photosensitive conductive paste in baking process # 16 Comb-shaped electrode conductor portion 23 made of conductive paste is subjected to main firing for 1 hour (however, at a peak time of 10 minutes at a temperature of 850 ° C.), and by simultaneous firing, electrode conductor portion 31 and electrode conductor portion 23 overlap each other and are electrically A conductive electrode is obtained on the insulating substrate 20.
[0064]
When the firing of the electrode conductor portions 31 and 23 on the insulating substrate 20 is finished, the moisture sensitive film 25 is applied so as to cover the pair of comb electrode conductor portions 23 in the moisture sensitive film coating step # 17, and the temperature is about room temperature to about 120 ° C. Dry at temperature.
[0065]
According to the second embodiment, since the terminal electrode conductor portion 31 for soldering is formed over the main surface and the side surface of the insulating substrate 20, solderability and solder heat resistance like ordinary chip parts are required. The portion that becomes the terminal electrode conductor portion 31 can be configured with a highly reliable electrode conductor portion that is free from problems of sufficient solder wettability, electrode thickness, and solder erosion by the non-photosensitive conductive paste, and is used for humidity detection. A precise and fine pattern can be formed on the electrode conductor portion 23.
[0066]
The manufacturing conditions and the like of the electrode conductor portion 23 for humidity detection are the same as those in the first embodiment described above, and other functions and effects are the same as those in the first embodiment.
[0067]
Also in the second embodiment, the terminal electrode conductor portion 31 for soldering with the non-photosensitive conductive paste may be applied in a predetermined pattern after the comb-shaped electrode conductor portion 23 with the photosensitive conductive paste is formed in a pattern. .
[0068]
FIG. 5 shows a third embodiment of the present invention. When a humidity sensor as an electronic component having a humidity detection function is manufactured, both end portions (main surface, back surface, and side surfaces) of the insulating substrate 20 are shown. Terminal electrode conductor portions 32 for soldering are formed over each of the five surfaces. The lead-out direction of the comb-shaped electrode conductor portion 23 for humidity detection is changed from that of the second embodiment in accordance with the arrangement of the terminal electrode conductor portion 32. Other configurations are the same as those of the second embodiment described above, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.
[0069]
In the third embodiment, since the terminal electrode conductor portions 32 for soldering are formed at both ends of the insulating substrate 20, there is an advantage that it can be handled in the same manner as a normal chip component. Other functions and effects are the same as those of the first embodiment.
[0070]
FIG. 6 shows a fourth embodiment of the present invention. In the case where a humidity sensor as an electronic component having a humidity detection function is manufactured, a through conductor provided with electrode conductor portions on the inner periphery at both ends of the insulating substrate 20 is shown. A terminal electrode conductor portion 33 for soldering having a shape obtained by dividing the hole into two is formed. The shape and lead-out position of the comb-shaped electrode conductor portion 23 for humidity detection are changed from those in the second and third embodiments in accordance with the arrangement of the terminal electrode conductor portion 33. The configuration of the fourth embodiment is a structure suitable for mass production. Other configurations and operational effects are the same as those of the above-described third embodiment.
[0071]
FIG. 7 shows a fifth embodiment of the present invention, which is an example in which a through hole with a high aspect ratio is provided in an electronic component having a humidity detection function, and an insulating substrate (or an element incorporating a humidity sensor). An example in which an electrode conductor portion made of a non-photosensitive conductive paste formed on the inner surface of the through hole and an electrode conductor portion made of a photosensitive conductive paste on the element main surface is connected to each other is shown.
[0072]
In this case, in the non-photosensitive conductive paste application step # 21, as shown in FIG. 7A, the electrode conductor portion 42 is coated with the non-photosensitive conductive paste on the inner peripheral portion of the through hole 41 of the insulating substrate 20 (or element) of the humidity sensor. And dried in the drying step # 22.
[0073]
Next, in the photosensitive conductive paste application step # 23, the photosensitive conductive paste 43 is applied to the main surface (here, the upper surface) of the insulating substrate 20 as shown in FIG. 7B, and dried in the drying step # 24. At this time, the upper end portion of the non-photosensitive conductive paste on the inner surface of the through hole and the photosensitive conductive paste are in contact with each other or partially overlap (the photosensitive conductive paste slightly enters the inside of the through hole by gravity).
[0074]
In the exposure and development step # 25, the photosensitive conductive paste 43 is exposed in a predetermined pattern, and then an unnecessary portion of the photosensitive conductive paste is removed by development processing, and the photosensitive conductive paste 43 is patterned as shown in FIG. The electrode conductor portion 44 is formed.
[0075]
Thereafter, in the firing step # 26, the electrode conductor portion 42 made of the non-photosensitive conductive paste and the electrode conductor portion 44 made of the photosensitive conductive paste are simultaneously fired so that the electrode conductor portion 42 and the electrode conductor portion 44 are in contact with each other or overlap each other. An electrically conductive electrode conductor is obtained on the insulating substrate 20.
[0076]
The conditions such as drying, exposure, and development may be the same as those in the first embodiment. Further, after forming the comb-shaped electrode conductor portion for detecting humidity by exposure and development of the photosensitive conductive paste 43 as in the first embodiment, a moisture sensitive film may be provided. Alternatively, a moisture sensitive film may be provided after a comb-shaped electrode conductor portion is formed by patterning a photosensitive conductive paste on another region or another surface of the insulating substrate 20.
[0077]
In the fifth embodiment shown in FIG. 7, by providing a non-photosensitive conductive paste on the inner surface of the through hole that is difficult to expose, the electrode conductor portion 42 can be formed also in the through hole portion having a high aspect ratio. As a result, an electronic component having a humidity detection function is provided, which includes an electrode conductor that is electrically connected to the electrode conductor portion 44 of the photosensitive conductive paste on the surface side. At this time, ultraviolet rays for exposure are transmitted through the end face of the through hole to a certain depth, so that the photosensitive conductive paste is also cured to the entrance of the through hole, and the inside of the through hole is an electrode conductor having a sufficient thickness. In addition to being covered, the thickness of the edge portion of the through hole can be increased to some extent, and the connection reliability is improved (both pastes can be present at the edge portion).
[0078]
Further, since the non-photosensitive conductive paste is used for the through hole portion, the through hole portion is not uncured, and the film thickness of the electrode conductor portion 42 can be sufficiently secured. For example, when the soldering terminal electrode conductor portion 33 shown in the fourth embodiment of FIG. 6 is configured by dividing the through hole having the electrode conductor portion into the inner surface obtained in the step of FIG. Even if soldering is performed using lead-free high-temperature solder, disconnection due to electrode biting does not occur.
[0079]
It should be noted that, as in the fifth embodiment of FIG. 7, the non-photosensitive conductive paste is placed on the bottom, and the photosensitive conductive paste is overlaid thereon. good. In this case, since the non-photosensitive paste can be applied after patterning first, the non-photosensitive conductive paste is applied to the developer (Na₂CO₃Solution).
[0080]
FIG. 8 shows a sixth embodiment of the present invention, which is an example in which a through hole with a high aspect ratio is provided in an electronic component having a humidity detection function, and is an insulating substrate (or an element incorporating a humidity sensor). An example in which an electrode conductor portion made of a non-photosensitive conductive paste formed on the inner surface of the through hole and an electrode conductor portion made of a photosensitive conductive paste on the element main surface are connected to each other so as to overlap each other is shown.
[0081]
In this case, as shown in FIGS. 8A and 8B, a tapered connection surface 41a is formed at the end of the through hole 41 formed in the insulating substrate 20 (or element) on the element main surface (upper surface) side. The angle of the connection surface 41a with respect to the main surface is preferably about 45 ° to 60 °, but may be tapered. Then, a non-photosensitive conductive paste is applied to the inner surface of the through hole 41 including the tapered connection surface 41a and dried to form the electrode conductor portion 42, and then the photosensitive conductive paste 43 is applied to the element main surface and the tapered connection surface 41a. And dry. At this time, as shown in FIGS. 8A and 8B, the non-photosensitive conductive paste and the photosensitive conductive paste on the tapered connection surface 41a at the end of the through hole overlap each other. Thereafter, the photosensitive conductive paste 43 is exposed in a predetermined pattern, an unnecessary portion of the photosensitive conductive paste is removed by a development process, and an electrode conductor portion 44 obtained by patterning the photosensitive conductive paste 43 is formed. Then, the electrode conductor portion 42 made of the non-photosensitive conductive paste and the electrode conductor portion 44 made of the photosensitive conductive paste are fired simultaneously (or separately fired) so that the electrode conductor portion 42 and the electrode conductor portion 44 overlap each other to be electrically Conductive electrode conductors are obtained on the insulating substrate 20. The conditions such as drying, exposure, and development may be the same as those in the first embodiment.
[0082]
In the sixth embodiment, by forming the tapered connection surface 41a at the end of the inner surface of the through hole 41 that is difficult to expose, the overlapping portion of the non-photosensitive conductive paste and the photosensitive conductive paste is prevented. It becomes wide enough and there are no defects such as edge breaks. Ultraviolet rays used for exposure are highly linear, but by attaching a taper of about 45 ° to 60 ° to the end of the through hole in this way, the photosensitive conductive paste can be reliably obtained up to the region where the tapered connection surface 41a is formed. Harden.
[0083]
The tapered connection surface may be a slope with a constant slope, or a slope with a gradually changing slope, such as an R plane or a U plane.
[0084]
Further, the inside of the through hole 41 may be filled with the electrode conductor portion 42 of the non-photosensitive conductive paste to form a via hole, and the electrode conductor portion 44 of the photosensitive conductive paste may be provided thereon.
[0085]
FIG. 8C shows an example in which a through hole having an electrode conductor portion on the inner periphery produced in FIGS. 8A and 8B is divided into two to form a terminal electrode conductor portion 47 for soldering. For example, FIG. The soldering terminal electrode conductor portion 33 shown in the fourth embodiment can be used as it is.
[0086]
If the soldering terminal electrode conductor provided in the electronic component having the humidity detection function has the structure of FIG. 8C, the inner surface of the circumferential concave surface obtained by dividing the through hole into two is the electrode conductor portion 42 of the non-photosensitive conductive paste. As a terminal electrode, there is sufficient conductor in the edge portion (both non-photosensitive and photosensitive conductive paste can be present in the edge portion). Even if it is used, it can be used as a highly reliable terminal electrode without worrying about solder erosion or disconnection.
[0087]
FIG. 9 shows a seventh embodiment of the present invention, in which the humidity sensor unit 50 is formed on the insulating substrate 20 (or element), and the chip elements 51 and the wirings 52 constituting the peripheral circuit are formed on the substrate 20. A composite part as an electronic part having a humidity detection function provided in FIG.
[0088]
In this case, the non-photosensitive conductive paste is applied to the main surface of the insulating substrate 20 (or element) such as alumina by using a screen printing machine or the like for the soldering electrode conductor 61 including the conductor pattern of the wiring 52 in FIG. Formed by pattern printing. Further, the comb-shaped electrode conductor portion 23 of the humidity sensor unit 50 is obtained by applying a photosensitive conductive paste to a predetermined range of the main surface of the insulating substrate 20 and exposing and developing. And after baking these electrode conductor parts 23 and 61, as shown in FIG.9 (B), the moisture sensitive film | membrane 25 is provided in the electrode conductor part 23, and the humidity sensor part 50 is comprised. Further, a predetermined type of chip element 51 is mounted on the solder pad of the wiring 52 on the substrate by soldering, and the lead terminal 56 is soldered to the soldering electrode conductor portion 61 at the substrate edge as shown in FIG. Attach. The moisture sensitive film 25 may be provided after mounting the components.
[0089]
The lead portion of the comb-shaped electrode conductor portion 23 of the humidity sensor portion 50 partially overlaps the wiring 52 and is electrically connected. Further, the substrate 20 may be provided with a through hole 55 to connect the front and back wirings 52. In this case, the through hole 55 is provided in the fifth embodiment of FIG. 7 or the sixth embodiment of FIG. It can be configured as a form. The specific manufacturing process of the sensor unit 50 is the same as that of the first embodiment.
[0090]
According to the seventh embodiment, the humidity sensor and its peripheral circuits can be integrated to further reduce the size as a whole. Other functions and effects are the same as those of the first embodiment described above.
[0091]
FIG. 10 shows an eighth embodiment of the present invention, and shows an example in which the comb-shaped electrode conductor portion 23 of the humidity sensor has a multilayer structure using plating together. In this case, the lowermost conductor film 70 of the comb-shaped electrode conductor portion 23 formed on the main surface of the substrate 20 is obtained by printing, exposing, developing, and firing a photosensitive conductive paste, and a silver paste as the photosensitive conductive paste. The cheapest and most common materials. The intermediate plating film 71 thereon is a solder erosion prevention layer and is an electroplating film of nickel or the like having solder corrosion resistance. The uppermost plating film 72 is an electroplating film having corrosion resistance against the moisture sensitive film 25 such as gold (Au).
[0092]
Other configurations are the same as those of the first embodiment described above, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.
[0093]
According to the eighth embodiment, the uppermost layer is formed of a plating film 72 made of gold or the like that is corrosion resistant to the dissociated ions of the moisture sensitive film 25, so that the conductive film 70 made of the lower photosensitive conductive paste is formed. The most common and inexpensive conductive material can be used.
[0094]
Note that the metal material of the photosensitive conductive paste may be a metal such as gold, silver, copper, palladium, platinum, nickel, or a mixture thereof. As the photosensitive material, an alkali developing binder monomer, a monomer, and an initiator are used. It is important that it is contained and volatilized and decomposed by firing so that no carbides remain in the pattern. However, when the comb-shaped electrode conductor portion has a single layer structure, it is necessary to have corrosion resistance with respect to the moisture sensitive film to be used because it is in direct contact with the moisture sensitive film. Further, when the comb-shaped electrode conductor portion has a multilayer structure as shown in FIG. 10, such a restriction on the lowermost photosensitive conductive paste is eliminated.
[0095]
Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.
[0096]
【The invention's effect】
As described above, according to the present invention, since all or part of the electrode conductor formed on the substrate or the element is configured using the photosensitive conductive material, the deterioration of the screen in the conventional screen printing method, etc. It is possible to eliminate the misalignment caused by the above, to improve the pattern position accuracy of the electrode conductor, and to extremely reduce the variation in product characteristics. In addition, even when the comb-shaped electrode conductor is formed in the area where the moisture sensitive film is to be formed, it is possible to perform patterning with a narrow pitch with high accuracy, so that the comb-shaped electrode conductor can be miniaturized and miniaturized. In addition, the effect of reducing variation in humidity measurement can be achieved.
[Brief description of the drawings]
FIG. 1 is a first embodiment of an electronic component having a humidity detection function and a method for manufacturing the same according to the present invention; an electrode conductor portion made of a photosensitive conductive paste; and an electrode conductor portion made of a non-photosensitive conductive paste; It is explanatory drawing which shows the example of the humidity sensor which is mutually connected.
FIG. 2 is a cross-sectional view showing a structure of a comb-shaped electrode conductor portion and its periphery in the first embodiment in comparison with the conventional one.
FIG. 3 is an explanatory diagram showing a vertical relationship between an electrode conductor portion made of a photosensitive conductive paste and an electrode conductor portion made of a non-photosensitive conductive paste in the first embodiment.
FIG. 4 is an explanatory diagram showing a second embodiment of the present invention.
FIG. 5 is a perspective view showing a third embodiment of the present invention.
FIG. 6 is a perspective view showing a fourth embodiment of the present invention.
FIG. 7 is an explanatory diagram showing an example having a through hole according to a fifth embodiment of the present invention.
FIG. 8 is an explanatory diagram showing another example of a through hole according to the sixth embodiment of the present invention and an example of a terminal electrode conductor portion obtained by dividing the through hole into two parts.
FIG. 9 is an explanatory diagram showing an example in which a composite part in which a humidity sensor and a peripheral circuit are integrated is manufactured as an electronic part having a humidity detection function according to a seventh embodiment of the present invention.
FIG. 10 is a cross-sectional view showing an example in which the comb-shaped electrode conductor portion has a multilayer structure according to the eighth embodiment of the present invention.
FIG. 11 is an explanatory diagram showing a manufacturing process of a conventional humidity sensor.
FIG. 12 is an explanatory diagram in the case of a manufacturing method in which a large number are obtained by screen printing on a conventional collective substrate.
[Explanation of symbols]
1,20 Insulating substrate
2 Terminal conductor electrode conductor
3,23 Comb electrode conductor
5, 26, 56 Lead terminal
10 Assembly board
21, 61 Soldering electrode conductor
22, 43 Photosensitive conductive paste
25 Moisture sensitive film
31, 32, 33, 47 Terminal electrode conductor
41,55 through hole
41a Connection surface
42,44 electrode conductor
50 Humidity sensor
51 chip elements
52 Wiring
70 Conductor film
71,72 Plating film

Claims (14)

In an electronic component having a humidity detection function in which a pair of electrode conductors are formed on an insulating substrate so as to face each other through a gap, and a moisture sensitive film is provided in the gap,
The moisture sensitive film is composed of a polymer film containing dissociative ions,
An electronic component having a humidity detection function, wherein the electrode conductor has a multilayer structure, the lowermost layer is made of a photosensitive conductive material, and at least the upper layer portion of the electrode conductor has corrosion resistance to the moisture sensitive film . The gap between the pair of electrode conductor is 20 to 100 [mu] m, an electronic component having a humidity detecting function according to claim 1, wherein the thickness of each electrode conductor, characterized in that a 3~20μm in the gap components. At least a part of ruthenium, ruthenium compounds, gold, or an electronic component having a humidity detecting function according to claim 1 or 2, wherein is composed of a gold compound of the electrode conductor. The electrode conductor has an electrode conductor portion having a conductor pattern formed by exposing and developing a photosensitive conductive paste on the main surface of the insulating substrate ; and an electrode conductor portion formed of a non-photosensitive conductive paste; and 4. The electronic component having a humidity detecting function according to claim 1 , wherein at least a part of both electrode conductor portions overlap each other to form an electrically conductive electrode conductor. 5. The humidity detecting function according to claim 4 , wherein the electrode conductor portion formed of the non-photosensitive conductive paste forms an end face electrode on an end face of the insulating substrate as at least a part of the electrode conductor. Electronic components. In an electronic component having a humidity detection function in which an electrode conductor is formed across the main surface of the element and the other surface in contact with the main surface,
An electrode conductor portion having a conductor pattern formed by exposing and developing a photosensitive conductive paste on the main surface, and an electrode conductor portion formed of a non-photosensitive conductive paste on the other surface, and the main surface An electronic component having a humidity detecting function, wherein at least a part of both electrode conductor portions overlap each other and form an electrically conductive electrode in the vicinity of a portion in contact with the other surface. The electrode having a humidity detecting function according to claim 6 , wherein the electrode conductor portion formed of the non-photosensitive conductive paste forms an end face electrode at an end face of the element as at least a part of the electrode conductor. parts. The element has a connection surface connecting the main surface and the other surface at a portion where the main surface and the other surface are in contact with each other, and a conductive pattern formed by exposing and developing the photosensitive conductive paste. The electronic component having a humidity detecting function according to claim 6, wherein an electrode conductor portion is formed by extending from the main surface to the connection surface. In the method of manufacturing an electronic component having a humidity detection function in which an electrode conductor and a moisture sensitive film are formed on the main surface of the element,
Forming a pair of electrode conductor portions so as to be opposed to each other with a conductor pattern exposed and developed on the main surface through a gap ;
Forming an electrode conductor portion with a non-photosensitive conductive paste;
Providing the moisture sensitive film,
Both electrode conductor portions are arranged on the surface of the element so that at least a part of both electrode conductor portions overlap , and
An electronic device having a humidity detection function, wherein a metal plating film having corrosion resistance to the moisture sensitive film is formed on at least an upper layer of the electrode conductor portion covered with the moisture sensitive film, and then a moisture sensitive film is provided in the gap. A manufacturing method for parts. In the method of manufacturing an electronic component having a humidity detection function in which an electrode conductor is formed across the main surface of the element and the other surface in contact with the main surface,
Forming an electrode conductor portion with a non-photosensitive conductive paste on the other surface;
A step of exposing and developing a photosensitive conductive paste on the main surface to form an electrode conductor portion comprising a conductor pattern;
A method of manufacturing an electronic component having a humidity detection function, wherein both electrode conductor portions are arranged on the main surface and the other surface so that at least a part of both electrode conductor portions overlap. The element has a connection surface connecting the main surface and the other surface at a portion where the main surface and the other surface are in contact with each other, and an electrode conductor portion made of a non-photosensitive conductive paste formed on the other surface is connected to the connection surface. The method of manufacturing an electronic component having a humidity detection function according to claim 10, wherein an electrode conductor portion made of a photosensitive conductive paste formed on the main surface is also extended to the connection surface. The electrode conductor portion formed by the photosensitive conductive paste formed on the main surface overlaps the surface of the electrode conductor portion formed by the non-photosensitive conductive paste formed on the other surface, and the conductive conductive paste is exposed and developed to form a conductor pattern. The method of manufacturing an electronic component having a humidity detection function according to claim 10 , wherein an electrode conductor formed so as to straddle the main surface and the other surface is formed. A pair of electrode conductor portions are formed so as to face each other through a gap with a conductive pattern obtained by exposing and developing the photosensitive conductive paste, and a metal plating film is formed on an upper layer of the electrode conductor portion covered with at least a moisture sensitive film. 13. A method for manufacturing an electronic component having a humidity detection function according to claim 10, 11 or 12 , wherein a moisture sensitive film is provided in the gap thereafter. The electrode conductor portion formed of a conductor pattern formed by exposing and developing the photosensitive conductive paste is at least partially baked to overlap the electrode conductor portion formed of the non-photosensitive conductive paste. A method for manufacturing an electronic component having a humidity detection function according to claim 9, 10, 11, 12, or 13 .

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