JP2016012492A - Conductive paste and method for forming pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive paste capable of securing satisfactory solderability even if being co-fired with ceramic paste essentially consisting of a glass frit, a method for forming a pattern using the conductive paste, and a glass object such as a glass antenna using the conductive paste.SOLUTION: Provided is conductive paste comprising conductive powder, a glass frit and an organic vehicle and also comprising a vanadium compound. Also provided is a method for forming a pattern where ceramic paste comprising ceramic powder essentially consisting of a glass frit and an organic vehicle is prepared, further the conductive paste is produced, the ceramic paste is coated on a glass substrate 1, thereafter, the conductive paste is coated on a ceramic dry film, and the ceramic dry film and the conductive paste are co-fired at 550 to 650°C for about 5 min in a non-reducing atmosphere such as an ambient air atmosphere to form a conductive film 5 with a prescribed pattern on a ceramic layer 4.

Description

  The present invention relates to a conductive paste and a pattern forming method. More specifically, the present invention relates to a conductive paste used for forming an antenna pattern attached to a window glass of a vehicle such as an automobile, and the conductive paste. The present invention relates to the pattern forming method used.

  In recent years, a glass antenna in which an antenna pattern is printed on a window glass for a vehicle such as an automobile has become widespread, receives radio waves from outside the vehicle via the glass antenna, and is used for radio and television.

  Conventionally, various conductive pastes for forming an antenna pattern have been developed, and a method for joining a glass antenna and a power feeding terminal using these conductive pastes has also been proposed.

  For example, in Patent Document 1, in a method in which a power supply terminal to a conductive wire of an automotive window glass is heated and bonded with a sintered body of silver paste and a lead-free solder alloy, the lead-free solder alloy is heated on the sintered body of silver paste. A first step of welding, a second step of heating and welding a lead-free solder alloy having the same composition as the lead-free solder alloy to a power supply terminal of an automotive window glass; A method of joining a window glass for an automobile and a power supply terminal, which comprises a third step for heat joining, has been proposed.

  In this Patent Document 1, a black ceramic having an antiglare action is applied on glass and dried. Then, an Ag paste is applied on the surface of the black ceramic and dried. The sintering and strengthening treatment of the Ag paste is performed at the same time, and the ceramic layer and the conductive film are simultaneously formed on the glass. And after that, the lead-free solder alloy is used, and the power supply terminal and the sintered body of the Ag paste are heat-bonded through the first to third steps described above.

JP 2014-96198 A (Claim 1, paragraph numbers [0038] to [0040], etc.)

  However, in Patent Document 1, since the black ceramic is mainly composed of glass frit, when the black ceramic and Ag paste are fired simultaneously, the glass frit in the black ceramic penetrates into the inside of the conductive paste, After sintering, there is a risk of reaching the surface of the conductive film or the vicinity of the surface. And when glass frit exists in the surface layer surface of the conductive film or in the vicinity of the surface layer in this way, sufficient solderability cannot be obtained when the conductive film and the power supply terminal are soldered together. There is a risk that the bonding strength between the two will decrease.

  The present invention has been made in view of such circumstances, and uses a conductive paste that can ensure good solderability even when simultaneously fired with a ceramic paste mainly composed of glass frit, and uses this conductive paste. An object of the present invention is to provide a pattern forming method.

  The present inventor conducted intensive studies to achieve the above object, and as a result, a vanadium compound (hereinafter referred to as “V compound”) is contained in the conductive paste, whereby the V compound is contained in the ceramic paste. Acquired knowledge that the glass frit reacts with the glass frit, thereby suppressing the glass frit in the ceramic paste from reaching the surface of the conductive film to the vicinity of the surface after sintering, and ensuring good solderability. It was.

  The present invention has been made based on such knowledge, and the conductive paste according to the present invention is printed on a ceramic dry film containing ceramic powder and glass frit, and is used for co-firing with the ceramic pattern. A conductive paste comprising at least a conductive powder, glass frit, an organic vehicle, and a V compound.

  In the conductive paste of the present invention, it is preferable that the V compound contains any one of V nitride and V carbide.

  These V nitrides and V carbides are stable without toxicity and can reduce the environmental load.

  Moreover, as for the electrically conductive paste of this invention, it is more preferable that content of the said V compound is 0.1-6.3 weight part with respect to 100 weight part of said electrically conductive powder.

  Furthermore, in the conductive paste of the present invention, it is more preferable that the content of the V compound is 0.6 to 6.3 parts by weight with respect to 100 parts by weight of the conductive powder.

  In the conductive paste of the present invention, the glass frit in the ceramic dry film is preferably amorphous.

  Thus, even if the ceramic dry film contains amorphous glass frit having a relatively high fluidity, it is possible to ensure good solderability by using the conductive paste.

  In the conductive paste of the present invention, it is also preferable that the conductive powder contains Ag as a main component.

  The pattern forming method according to the present invention includes a step of preparing a ceramic paste containing a ceramic powder containing glass frit and an organic vehicle, at least a conductive powder, a glass frit, a V compound, and an organic vehicle. Forming a conductive paste containing a ceramic paste, applying the ceramic paste onto a substrate to form a ceramic dry film, applying the conductive paste onto the ceramic dry film, and drying the ceramic. And a step of simultaneously firing the film and the conductive paste to form a conductive film having a predetermined pattern on the ceramic layer.

  In the pattern forming method of the present invention, the glass frit in the ceramic paste is preferably amorphous.

  According to the conductive paste of the present invention, a conductive paste is printed on a ceramic dry film containing ceramic powder and glass frit, and is fired simultaneously with the ceramic dry film, and at least the conductive powder and glass Since the frit and the organic vehicle are contained and the V compound is contained, when the ceramic dry film and the conductive paste are fired simultaneously, the glass frit in the ceramic dry film penetrates into the conductive paste. However, it is possible to suppress the V compound from reacting with the glass frit and thereby reaching the surface layer surface of the conductive film, which is a sintered body of the conductive paste, or the vicinity of the surface layer. Deterioration can be suppressed.

  According to the pattern forming method of the present invention, a step of preparing a ceramic paste containing a ceramic powder containing glass frit and an organic vehicle, at least a conductive powder, glass frit, a V compound, and an organic vehicle are prepared. A step of producing a contained conductive paste, a step of applying the ceramic paste on a substrate to form a ceramic dry film, a step of applying the conductive paste on the ceramic dry film, and the ceramic dry film And the step of simultaneously firing the conductive paste and forming a conductive film having a predetermined pattern on the ceramic layer, the glass frit in the ceramic dry film is electrically conductive during the simultaneous firing of the ceramic dry film and the conductive paste. V compound reacts with the glass frit in the ceramic dry film even if it penetrates into the adhesive paste From Rukoto, can prevent the glass frit reaches surface layer to near surface layer of the conductive film, it is possible to form a conductive film of good predetermined pattern of solderability.

It is sectional drawing which shows one Embodiment of the glass antenna obtained using the electrically conductive paste which concerns on this invention.

  Next, an embodiment of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view schematically showing one embodiment of a glass antenna manufactured using the conductive paste according to the present invention.

  This glass antenna is made of laminated glass in which an intermediate film 3 formed of polyvinyl alcohol resin or the like is interposed between a plurality of glass bases (first and second glass bases 1 and 2), and considers impact resistance. It is structured.

  A ceramic layer 4 is formed on the surface of the first glass substrate 1, and a conductive film 5 having a predetermined pattern having an antenna function is formed on the surface of the ceramic layer 4. The conductive film 5 is soldered to a power supply terminal (not shown), and is mounted on the front portion of a vehicle such as an automobile, receives radio waves from the outside of the vehicle, and is used for radio or television.

  Next, the conductive paste for forming the conductive film 5 will be described in detail.

  This conductive paste contains at least conductive powder, glass frit, and an organic vehicle, and contains a V compound, whereby the solderability of the conductive film 5 is improved, and the conductive film 5 is fed with power. The joint strength with the terminal is improved.

  That is, in the glass antenna, the ceramic layer 4 and the conductive film 5 are usually formed by simultaneously firing a ceramic dry film containing ceramic powder and glass frit and a conductive paste.

  However, since the glass frit is contained in the ceramic dry film as described above, the glass frit in the ceramic dry film penetrates into the inside of the conductive paste at the time of firing, and the glass frit forms the conductive film 5 after firing. The surface layer surface or the vicinity of the surface layer surface is reached, so that the solderability of the conductive film is deteriorated, and the bonding strength between the conductive film 5 and the power supply terminal may be lowered. In particular, when the glass frit is amorphous, the glass frit has an advantage that it is easily softened and can be fired at a lower temperature. The segregation to the vicinity is promoted, and the deterioration of solderability becomes remarkable.

  Therefore, in the present invention, a V compound is contained in the conductive paste, and the glass frit that has entered the conductive paste during firing is reacted with the V compound, so that the glass frit reaches the surface layer surface of the conductive film 5 or near the surface layer. This suppresses the deterioration of the solderability, thereby improving the bonding strength between the conductive film 5 and the power supply terminal.

Here, the V compound is not particularly limited, and V ₂ O ₅ that is V oxide, VN that is V nitride, VC that is V carbide, and the like can be used, but there is no toxicity. It is preferable to use VN or VC that is stable and can easily react with the glass frit and suppress the deterioration of solderability more effectively.

  Further, the content of the V compound in the conductive paste is not particularly limited, but is preferably 0.1 to 6.3 parts by weight, more preferably 0.8 to 100 parts by weight of the conductive powder. 6 to 6.3 parts by weight. That is, if a V compound is contained in the conductive paste, the V compound reacts with the glass frit, so that an effect of improving solderability can be achieved. However, when the V compound is less than 0.1 part by weight with respect to 100 parts by weight of the conductive powder, the content of the V compound is small, and thus there is a possibility that the effect of improving the solderability cannot be obtained sufficiently. On the other hand, when the V compound exceeds 6.3 parts by weight with respect to 100 parts by weight of the conductive powder, the V compound existing on the surface layer surface of the conductive film 5 or in the vicinity of the surface layer increases. May be disturbed, leading to deterioration of solderability.

  The conductive powder is not particularly limited as long as it is a metal powder having good conductivity, but normally, Ag powder having good conductivity can be preferably used. Moreover, you may make Ag powder a main component and contain various metal powders, such as Pd, Pt, Ni, Cu, as a subcomponent.

  The shape of the conductive powder is not particularly limited, and may be, for example, a spherical shape, a flat shape, an irregular shape, or a mixed powder thereof.

The average particle diameter D ₅₀ of the conductive powder is not particularly limited, but from the viewpoint of ensuring good sensitivity by reducing the line resistance of the antenna pattern, the average particle diameter D ₅₀ is 0.05 to 10 μm. Is preferred. If the average particle diameter D ₅₀ of the conductive powder is less than 0.05 μm, the viscosity increases during paste preparation, making it difficult to make a paste. On the other hand, if the average particle diameter D ₅₀ of the conductive powder exceeds 10 μm, the line resistance Tend to be larger.

  Further, the content of the conductive powder in the conductive paste is not particularly limited, but is preferably 55 to 95 wt%. When the content of the conductive powder is less than 55 wt%, the content of the glass frit is relatively increased. Therefore, in order to ensure the desired conductivity, the line width is increased or the conductive film is made thicker. There is a risk of increasing costs. On the other hand, if the content of the conductive powder exceeds 95 wt%, the conductive powder becomes excessive and it may be difficult to form a paste. Therefore, although content of electroconductive powder is not specifically limited, 55-95 wt% is preferable.

The component composition of the glass frit in the conductive paste is not particularly limited, and Bi ₂ O ₃ , PbO, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , BaO, CaO, SrO, ZnO, From various oxides such as Na ₂ O, K ₂ O, Li ₂ O, Sb ₂ O ₃ , FeO, and CuO, the component composition can be determined in consideration of the softening point and chemical durability.

Further, the average particle diameter D ₅₀ of the glass frit is not particularly limited, but from the viewpoint of adhesion between the first glass substrate 1 and the conductive film 5 and sinterability of the conductive paste, 0.1 to 5.0 μm is preferable.

  The content of the glass frit in the conductive paste is not particularly limited, but it is 0.1 to 5.0 wt in consideration of the fixing property to the first glass substrate 1 and the soldering property to the power supply terminal. % Is preferred.

  Moreover, the organic vehicle is prepared so that binder resin and the organic solvent may become 1-3: 7-9 by volume ratio, for example. The binder resin is not particularly limited, and for example, ethyl cellulose resin, nitrocellulose resin, acrylic resin, alkyd resin, or a combination thereof can be used. Also, the organic solvent is not particularly limited, and α-terpineol, xylene, toluene, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, etc. alone or in combination thereof Can be used.

  Then, this conductive paste is obtained by weighing and mixing conductive powder, glass frit, V compound and organic vehicle so as to have a predetermined mixing ratio, and dispersing and kneading using a three-roll mill or the like, It can be manufactured easily.

  The conductive paste thus formed contains at least a conductive powder, a glass frit, an organic vehicle, and contains a V compound, so that the ceramic dry film and the conductive paste were simultaneously fired. In this case, even if the glass frit in the ceramic dry film penetrates into the inside of the conductive paste, the V compound reacts with the glass frit and reaches the surface layer surface of the conductive film which is a sintered body of the conductive paste or near the surface layer. Can be suppressed, and sufficient bonding strength can be obtained without deteriorating the solderability of the conductive film and the power supply terminal.

  Next, the manufacturing method of the said glass antenna including the pattern formation method of this invention is explained in full detail.

  First, a ceramic paste containing a ceramic powder containing glass frit and an organic vehicle is prepared.

The ceramic powder containing glass frit is not particularly limited, and ZnO, Al ₂ O ₃ , B ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , alkali metal oxide, alkaline earth metal oxide, etc. It can be appropriately selected from the above as necessary, and can be used after blending into a predetermined composition.

  The glass frit is also preferably amorphous. Amorphous glass frit is easy to soften during firing and is rich in fluidity, and therefore can be fired at a relatively low temperature.

In addition, since the present glass antenna is usually installed in a front part of a vehicle or the like, it is also preferable to add a black pigment such as Cr ₂ O ₃ or CuO having an antiglare action to the ceramic paste.

  In addition, the organic vehicle can use the thing similar to the electrically conductive paste of this invention mentioned above.

  Next, the conductive paste of the present invention is produced by the method described above.

  Next, a ceramic paste is applied to a predetermined portion of the first glass substrate 1 using a screen printing method and dried to form a ceramic dry film.

  The ceramic dry film removes the organic solvent in the ceramic paste by the drying process. However, the organic solvent does not need to be completely removed, as long as it does not mix with the conductive paste during firing. Good.

  Next, a conductive paste is applied on the ceramic dry film using a screen printing method so as to form an antenna pattern and dried.

  Then, the first glass substrate 1 on which the ceramic dry film and the dry film of the conductive paste are formed is fired at a temperature of 550 to 650 ° C. for about 5 minutes in a non-reducing atmosphere such as an air atmosphere. A first glass substrate 1 on which the layer 4 and the conductive film 5 are formed is obtained.

  Thereafter, the intermediate film 3 is pasted through an adhesive so that the first glass substrate 1 and the second glass substrate 2 are sandwiched, and is thus manufactured.

  Thus, in the present glass antenna, even when the amorphous glass frit is contained in the ceramic paste, the amorphous glass frit reacts with the V compound in the conductive paste. Segregation in the vicinity of the layer surface or the surface layer surface can be suppressed, and a glass antenna having good solderability and good bonding strength between the conductive film 5 and the power supply terminal can be obtained.

  The present invention is not limited to the above embodiment. In the above embodiment, the glass frit in the ceramic paste is preferably amorphous, but it goes without saying that it can also be used for a crystalline glass frit that is inferior in fluidity to the amorphous glass frit.

  The conductive paste only needs to contain conductive powder, glass frit, a V compound, and an organic vehicle, and various inorganic components can be contained as necessary within a range that does not affect the characteristics. For example, Al, Ti, Zr, P, Ce, Cr, Mn, Co, Nb, Ta, W, Pd, Ag, Ru, Sn, In, Y, Dy, La, or the like may be included. In addition, the form of inclusion is not particularly limited, and is appropriately selected from oxides, hydroxides, peroxides, halides, carbonates, nitrates, phosphates, sulfates, fluorides, organometallic compounds, and the like. can do.

  Moreover, it is also preferable to add 1 type or these combinations of plasticizers, such as di 2-ethylhexyl phthalate and dibutyl phthalate, to this electrically conductive paste as needed. It is also preferable to add a rheology modifier such as a fatty acid amide or a fatty acid, and a thixotropic agent, a thickener, a dispersant, etc. may be added.

  Next, examples of the present invention will be specifically described.

[Sample preparation]
The average particle diameter D ₅₀ 3 [mu] m Ag powder, average particle diameter D ₅₀ was prepared _{VN, VC, V 2 O 5} , ZrO 2, and TiO ₂ as a Bi-B-Ba-based glass frit, and additives 2μm .

  Moreover, the organic vehicle was produced with the following method. That is, the organic cellulose was prepared by mixing the ethyl cellulose resin and texanol so that the binder resin was 10 wt% ethyl cellulose resin and the organic solvent was 90 wt% texanol.

  Next, Ag powder, glass frit, each additive, and organic vehicle were blended so that the contents of Ag powder, glass frit, each additive, and organic vehicle were as shown in Table 1, and mixed with a planetary mixer. Later, the paste was dispersed and kneaded with a three-roll mill to prepare conductive pastes of sample numbers 1 to 19.

(Sample evaluation)
A ceramic paste containing glass frit was prepared. The glass frit contains SiO ₂ , Bi ₂ O ₃ , B ₂ O ₃ as main components, Al ₂ O ₃ , Li ₂ O, Na ₂ O, and further contains Cr ₂ O ₃ , CuO as black pigments. I prepared something.

  Next, a slide glass having a length of 76 mm, a width of 26 mm, and a thickness of 1.4 mm was prepared. And the said ceramic paste was apply | coated to the slide glass by screen-printing so that it might become a rectangular shape of length: 22.0mm and width: 6.0mm. Next, the glass slide was dried at a temperature of 150 ° C. for 10 minutes, and then the conductivity of Sample Nos. 1 to 19 using a screen printing method so as to form a square shape of 2.0 mm in length and 2.0 mm in width. Each paste was applied. Next, this glass slide is dried again at a temperature of 150 ° C. for 10 minutes, and then each dry film of the ceramic paste and the conductive paste is simultaneously fired at a maximum temperature of 600 ° C. for 5 minutes to form a conductive film on the ceramic layer. Samples 1 to 19 were prepared.

  Next, the surface of the conductive film of each sample Nos. 1 to 19 is polished with a sand-containing eraser, a flux in which rosin is dissolved in isopropyl alcohol is applied to the surface of the conductive film, and Sn—Pb—Ag solder is stored. Then, it was immersed in a solder bath heated to 230 ° C. for 2 seconds to evaluate solderability.

  Table 1 shows the component composition of the conductive paste, the content of each additive with respect to 100 parts by weight of Ag powder, and the solderability.

  For solderability, the solder coating amount is judged visually, and the solder coating amount is 70% or more excellent “◎”, less than 70% 50% or more is good “◯”, and less than 50% is 30% or more. “△” and less than 30% were regarded as “No” and evaluated.

Sample numbers 16 and 17 were found to be inferior in solder wettability because ZrO ₂ was used as an additive. This is presumably because ZrO ₂ does not react with the glass frit in the ceramic paste, so that the glass frit is present in the surface layer surface of the conductive film or in the vicinity of the surface layer surface during firing.

Since Sample Nos. 18 and 19 use TiO ₂ as an additive, it was found that the solder wettability is inferior for the same reason as Sample Nos. 16 and 17.

  On the other hand, since the sample numbers 1-15 used the V compound for the additive, it turned out that the solderability is improved compared with sample numbers 16-19.

However, since sample numbers 12 to 15 use V ₂ O ₅ as an additive, the effect of improving solderability was small.

  Sample Nos. 1 and 7 use VN and VC as additives, respectively, but have a small content of 0.06 parts by weight with respect to 100 parts by weight of Ag powder, and the effect of improving solderability is small. I understood.

  In Sample Nos. 6 and 11, since the contents of VN and VC were too much with 7.5 parts by weight with respect to 100 parts by weight of Ag powder, the solderability deteriorated. This is probably because VN and VC are contained in a large amount, and therefore VN and VC that inhibit contact between Ag and solder exist on the surface of the conductive film or in the vicinity of the surface.

  On the other hand, Sample Nos. 2 to 5 and 8 to 10 have a VN or VC content of 0.1 to 6.3 parts by weight with respect to 100 parts by weight of Ag powder, and an appropriate VN in the conductive paste. Or since VC was contained, it turned out that favorable solderability is acquired.

  In particular, Sample Nos. 3 to 5, and 9, 10 have a VN or VC content of 0.6 to 6.3 parts by weight with respect to 100 parts by weight of Ag powder, thereby obtaining better solderability. I found out that

  Even when fired simultaneously with the ceramic dry film, the deterioration of solderability can be suppressed, and a conductive paste having good bonding strength with the power supply terminal can be obtained.

1 First glass substrate (substrate)
4 Ceramic layer 5 Conductive film

Claims (8)

A conductive paste printed on a ceramic dry film containing ceramic powder and glass frit and co-fired with the ceramic dry film,
Including at least conductive powder, glass frit, and an organic vehicle,
A conductive paste containing a vanadium compound.   The conductive paste according to claim 1, wherein the vanadium compound includes any one of vanadium nitride and vanadium carbide.   3. The conductive paste according to claim 1, wherein a content of the vanadium compound is 0.1 to 6.3 parts by weight with respect to 100 parts by weight of the conductive powder.   3. The conductive paste according to claim 1, wherein a content of the vanadium compound is 0.6 to 6.3 parts by weight with respect to 100 parts by weight of the conductive powder.   6. The conductive paste according to claim 1, wherein the conductive powder contains Ag as a main component.   The conductive paste according to any one of claims 1 to 5, wherein the glass frit in the ceramic dry film is amorphous. Preparing a ceramic paste containing a ceramic powder containing glass frit and an organic vehicle;
Producing a conductive paste containing at least a conductive powder, a glass frit, a vanadium compound, and an organic vehicle;
Applying the ceramic paste on a substrate to form a ceramic dry film;
Applying the conductive paste onto the ceramic dry film;
And a step of simultaneously baking the ceramic dry film and the conductive paste to form a conductive film having a predetermined pattern on the ceramic layer.   The pattern forming method according to claim 8, wherein the glass frit in the ceramic paste is amorphous.

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