JP2006331936A - Ceramic heater and heating iron using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic heater which is used for a long time by improving durability of a joint part of a lead member in the ceramic heater against a cold cycle, and also to provide a heating iron using the same. <P>SOLUTION: In this ceramic heater having a ceramic body 1 wherein a heating resistor 2 and a drawing pattern 3 connected with the heating resistor 2 are buried, a through hole 4 formed in the ceramic body 1, a through hole conductor layer 5 formed at least in an inner circumference of the through hole 4 and an electrode pad pattern 6 connected with the through hole conductor layer 5 on the ceramic body 1 surface, a lead member 7 is connected at least with the electrode pad pattern 6, and a metal material 9 is filled between the conductor layer 5 and the drawing pattern 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ceramic heater and a heating iron using the ceramic heater, and more particularly to an air-fuel ratio sensor heating heater for automobiles, a heater for vaporizer, a glow plug, a vaporizer, an oil stove ignition / vaporizer, and a sealing machine. The present invention relates to ceramic heaters used for various industrial equipment, heaters for soldering irons, heaters for hair irons, and the like, and heating irons using the same.

  Conventionally, a columnar ceramic heater as shown in FIG. 4A has been widely used as a heater for an automobile such as a heater for heating an air-fuel ratio sensor. In this ceramic heater, for example, a heating resistor 22 made of a refractory metal such as W, Re, or Mo is embedded in a ceramic body 21 mainly composed of alumina, and is formed at an end portion of the heating resistor 22. A lead member 27 is connected to the drawn pattern 23 via an electrode pad 26 (see, for example, Patent Document 1 and Patent Document 2).

  The cylindrical ceramic heater can be manufactured, for example, as follows. That is, as shown in FIG. 4B, a ceramic core 31 and ceramic green sheets 30a and 30b are prepared, and a paste of a refractory metal such as W, Re, or Mo is applied to one main surface of the ceramic green sheet 30a. Printing is performed to form the heating resistor 22 and the drawing pattern 23. Next, the ceramic green sheet 30 obtained by laminating the ceramic green sheet 30a and the ceramic green sheet 30b is wound around the ceramic core 31 and the whole is baked and integrated, and then the lead member is attached. In the ceramic green sheet 30b, as shown in FIG. 4B, a through hole 24 is formed at a position corresponding to the vicinity of the end of the lead pattern 23 connected to the heating resistor 22, and this through hole 24 is formed. A through-hole conductor layer 25 is formed on the inner side surface. Thus, the lead pattern 23 in the fired ceramic body 21 is electrically connected to the electrode pad 26 through the through-hole conductor layer 25 (see FIG. 4C).

The electrode pad 26 and the through-hole conductor layer 25 are formed with a plating layer 28 made of a heat-resistant metal material such as Ni or Cr. Further, the through hole 24 is filled with a brazing material 29. The brazing material 29 is also filled between the lead member 27 made of a heat-resistant metal material containing Fe—Ni alloy, Ni, Cr, and the like and the electrode pad 26, and the lead member 27 is brazed to the electrode pad 26. It is joined. When the lead member 27 is energized, the heating resistor 22 generates heat. A plating layer is further formed on the surface of the brazing material 29 (not shown).
JP 2001-126852 A JP-A-11-354255

  By the way, in the conventional ceramic heater as described above, since the thermal history is repeatedly applied to the electrode pad 26 to which the lead member is attached, the joint portion between the electrode pad 26 and the lead member 27 deteriorates and leads. The member may come off and there was a problem in terms of durability.

  In recent years, regulations on automobile exhaust gas have become stricter, and it is necessary to increase the rising speed of an oxygen sensor used for air-fuel ratio control. For this reason, it is necessary to improve the start-up characteristics of the ceramic heater, so that the operating temperature of the ceramic heater is increased, and the above-described problem becomes remarkable.

  In particular, a ceramic heater used for automobiles is required to have high reliability. Therefore, it is not preferable that even one of the 1000 heaters has the above-described defect.

  In addition, as lead-free solder has recently been developed, the temperature of the heater has been increased and the temperature difference applied to the electrode pad portion to which the lead member is attached tends to increase accordingly. Furthermore, hair irons and the like are becoming smaller, and the distance between the heat generating portion and the electrode pad tends to be shortened, and a thermal history with a large temperature difference is applied to the electrode pad.

  The present invention has been devised in view of the above-described problems, and an object of the present invention is to improve the durability of a joint portion of a lead member in a ceramic heater with respect to a cooling cycle, and to be used over a long period of time. It is in providing the heating iron using this.

  As a result of intensive studies to solve the above problems, the present inventor filled a metal material in a constricted portion such as between the through-hole conductor layer and the lead pattern, and joined the metal material to the lead member. The present inventors have found a new fact that the joint strength of the lead member can be remarkably improved and have completed the present invention.

  That is, the ceramic heater of the present invention is a ceramic body in which a heating resistor, a lead pattern connected to the heating resistor, the heat generating resistor and the lead pattern are embedded, and a through hole reaching the lead pattern is formed. A through-hole conductor layer formed on at least an inner surface of the through-hole, an electrode pad pattern electrically connected to the through-hole conductor layer and formed on the surface of the ceramic body, and the electrode pad pattern In the ceramic heater having the electrically connected lead member, the through-hole conductor layer has a thin region confined to the inner surface side of the through-hole, and the thin material is filled with a metal material. The metal material is bonded to the lead member.

  In the present invention, it is preferable that the thin region is located at a position closer to the lead pattern than the maximum thickness portion of the through-hole conductor layer and in the vicinity of the maximum thickness portion.

  Further, the ceramic heater of the present invention is a ceramic body in which a heat generating resistor, a lead pattern connected to the heat generating resistor, the heat generating resistor and the lead pattern are embedded, and a through hole reaching the lead pattern is formed. A through-hole conductor layer formed on at least an inner surface of the through-hole, an electrode pad pattern electrically connected to the through-hole conductor layer and formed on the surface of the ceramic body, and the electrode pad pattern In a ceramic heater having an electrically connected lead member, a metal material is filled between the through-hole conductor layer and the lead pattern, and the metal material is bonded to the lead member. Features.

  In the present invention, the metal material is preferably filled in the through hole and joined to the lead member.

  In the present invention, the metal material is preferably a brazing material.

  Furthermore, in the present invention, a metal plating layer is formed on the surface of the through-hole conductor layer and the surface of the lead electrode pattern in the portion where the through-hole is formed, and the metal on the surface of the through-hole conductor layer is formed. More preferably, the metal material is filled between the plating layer and the metal plating layer on the surface of the lead-out pattern.

  In the present invention, it is preferable that the lead-out pattern has a portion in which the through-hole is formed bulges toward the through-hole.

  In the present invention, it is preferable that the surface roughness (Ra) of the electrode pad pattern and the through-hole conductor layer is 1 μm or more, and the lead member is fixed on the electrode pad pattern using a brazing material.

  The thickness of the through-hole conductor layer in the present invention is preferably 5% to 25% of the through-hole diameter.

  Moreover, it is preferable that the thickness of the through hole conductor layer in the present invention is thicker on the lead-out pattern side than on the opening side of the through hole.

  Furthermore, it is preferable that the thickness of the through-hole conductor layer in the present invention gradually increases from the through-hole opening side toward the lead-out pattern side.

  Furthermore, in this invention, it is preferable that the maximum diameter of the glass particle which has Si as a main component which exists in the surface of the said through-hole conductor layer is 100 micrometers or less.

  The heating iron of the present invention is characterized in that the ceramic heater is used as a heating means.

  According to the ceramic heater of the present invention, the through-hole conductor layer has a thin region confined to the inner surface side of the through-hole, and the thin region is filled with a metal material, and the metal material is Since it is bonded to the lead member, the metal material filled in the narrow and thin area exerts an anchor effect and a wedge effect, and the bond strength between the lead member and the ceramic body is dramatically improved. Even if it exists, the joining strength (tensile strength) of the lead member is high and the durability is excellent.

  In particular, since the thin region is located closer to the lead pattern than the maximum thickness portion of the through-hole conductor layer and in the vicinity of the maximum thickness portion, the thin thickness region is filled. The anchor effect of the metal material is further improved.

  According to the ceramic heater of the present invention, the metal material is filled between the through-hole conductor layer and the lead pattern, and the metal material is bonded to the lead member. The joint strength is dramatically improved, and the lead member has a high joint strength (tensile strength) and excellent durability even after the thermal cycle.

  A metal plating layer is formed on the surface of the through hole conductor layer and the surface of the lead electrode pattern in the portion where the through hole is formed, and a metal material is interposed between the through hole conductor layer on which the metal plating layer is formed and the lead pattern. When filled, the metal material that can withstand high temperatures can be densely filled, so that the durability is further improved.

  Furthermore, when the lead-out pattern in the portion where the through hole is formed is convexly raised on the through hole side, the stress concentration on the through hole conductor layer due to the thermal expansion of the metal material is alleviated, and cracks are generated. It is suppressed and the joining durability of the lead member is further improved.

  Also, when the surface roughness (Ra) of the electrode pad pattern and through-hole conductor layer is 1 μm or more and the lead member is fixed on the electrode pad pattern using a brazing material, the contact area between the brazing material and the through-hole conductor layer Since the contact area between the brazing material and the electrode pad is increased, the bonding strength is improved and the durability is further improved.

  Furthermore, the heating iron of the present invention uses the ceramic heater as a heating means, and therefore exhibits excellent durability even when rapid heating is repeated.

Hereinafter, embodiments of the ceramic heater of the present invention will be described with reference to the drawings.
1A and 1B are views showing an embodiment of the ceramic heater of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a partial cross-sectional view showing the periphery of an electrode pad portion of FIG.
The ceramic heater according to the present embodiment includes a heating resistor 2, a lead pattern 3 connected to the heat generating resistor 2, the heat generating resistor 2 and the lead pattern 3, and a through hole 4 reaching the lead pattern 3. The formed ceramic body 1, the through hole conductor layer 5 formed on the inner surface of the through hole 4, and the electrode pad pattern formed on the surface of the ceramic body 1 electrically connected to the through hole conductor layer 5 6 and a lead member 7 electrically connected to the electrode pad pattern 6.

  A metal plating layer 8 is formed on the surface of the through-hole conductor layer 5 and the surface of the lead electrode pattern 3 in the portion where the through-hole 4 is formed. The through hole 4 is filled with a metal material 9. The metal material 9 is also filled between the electrode pad pattern 6 and the lead member 7. Thereby, the lead member 7 is bonded to the electrode pad pattern 6 and is electrically connected to the electrode pad pattern 6, and is electrically connected to the lead pattern 3 and the heating resistor 2 through the through-hole conductor layer 5. It has a structured.

  FIG. 2A is an enlarged cross-sectional view around the through hole 4 in FIG. As shown in FIG. 2A, the ceramic heater according to the present embodiment is characterized in that a metal material 9 is filled between the through-hole conductor layer 5 and the lead pattern 3. That is, the through-hole conductor layer 5 has a thin region (between the through-hole conductor layer 5 and the lead pattern 3) confined to the inner surface side of the through-hole 4, and the metal material 9 is formed in the thin region. Is filled. As shown in FIG. 2A, this thin region is located closer to the lead pattern 3 than the maximum thickness portion of the through-hole conductor layer 5 and in the vicinity of the maximum thickness portion. The metal material 9 is filled in the through hole 4 and joined to the lead member 7 (see FIG. 1B). That is, since the anchor effect is obtained by the metal material 9 filled between the through-hole conductor layer 5 and the lead-out pattern 3, the bonding strength between the metal material 9, the through-hole conductor layer 5 and the electrode pad pattern 6 is improved. . As a result, the bonding strength between the lead member 7 and the electrode pad pattern 6 is improved, and the bonding strength (tensile strength) of the lead member 7 is maintained even when the thermal history due to the thermal cycle is received. A highly durable ceramic heater can be obtained.

  As the metal material 9, it is preferable to use a brazing material such as Ag-Cu, Ag, or Au-cu. As a result, the bonding strength at high temperature is improved, and a ceramic heater having higher durability against the cooling cycle can be obtained. In general, the brazing material has a melting point of 600 ° C. or more, is superior in high temperature durability as compared with solder, and is excellent in oxidation resistance even in a cooling / heating cycle, and thus is preferable as the metal material 9.

  The metal material 9 is more preferably filled between the through-hole conductor layer 5 and the lead pattern 3 via the metal plating layer 8. In the present embodiment, as shown in FIG. 2A, a metal plating layer 8 is formed on the surface of the through-hole conductor layer 5 and the surface of the lead electrode pattern 3 in the portion where the through-hole 4 is formed. That is, the metal material 9 is filled between the metal plating layer 8 on the surface of the through-hole conductor layer 5 and the metal plating layer 8 on the surface of the lead pattern 3. Thereby, the joining strength of the lead member 7 is further improved, and a ceramic heater having higher durability can be obtained. By forming the metal plating layer 8, the wettability of the metal material 9 such as a brazing material is improved and the filling degree of the metal material 9 is also improved, so that the bonding strength is remarkably improved and the durability is remarkably improved. Examples of the material constituting the metal plating layer 8 include Ni, Au, and Cr.

  Further, as shown in FIG. 2A, the lead-out pattern 3 has a portion 12 in which the portion where the through hole 4 is formed is raised in a convex shape toward the opening side of the through hole 4. Is more preferable. By having this convex-shaped part 12, the stress by the thermal expansion of the metal material 9 which generate | occur | produces in a thermal cycle can be disperse | distributed, between the through-hole conductor layer 5 and the metal material 9, and a metal plating layer The occurrence of cracks between 8 and the metal material 9 can be suppressed, and a more durable ceramic heater can be obtained. Furthermore, when the convex portion 12 is gently curved, the stress concentration due to the thermal expansion of the metal material 9 generated in the cooling cycle is more effectively suppressed as compared with the case where the convex portion 12 is a sharp convex shape. Can do.

  The surface roughness (Ra) of the through-hole conductor layer 5 and the electrode pad pattern 6 is 1 μm or more, preferably 5 to 10 μm. As described above, by providing irregularities on the surface of the through-hole conductor layer 5 and the electrode pad pattern 8, the contact area can be increased and the bonding strength with the metal material 9 can be further improved. On the other hand, if the surface roughness (Ra) is less than 1 μm, the bonding strength may not be sufficiently obtained. This surface roughness can be measured using a non-contact type three-dimensional surface roughness measuring device or the like.

  The thickness of the through-hole conductor layer 5 formed on the inner surface of the through-hole 4 is preferably in the range of 5 to 25% of the diameter of the through-hole 4. When the thickness of the through-hole conductor layer 5 is less than 5% of the diameter of the through-hole 4, the adhesion strength of the through-hole conductor layer 5 to the inner surface of the through-hole 4 is not sufficiently secured, and the metal material 9 of the through-hole conductor layer 5 is not cooled. There is a possibility that cracks (delamination) may occur between the metal material 9 due to stress accompanying thermal expansion. Moreover, if it exceeds 25% of the diameter of the through-hole 4, an initial crack will generate | occur | produce on the surface of the through-hole conductor layer 5, and there exists a possibility that durability may deteriorate by the influence.

  Further, as shown in FIG. 2A, the through hole conductor layer 5 is preferably formed so that the lead pattern 3 side is thicker than the through hole 4 opening side. As described above, the thickness on the opening side is small and the thickness on the drawing pattern 3 side is thick, so that the stress concentration in the through hole 4 due to the thermal expansion of the metal material 9 can be reduced. Further, by increasing the thickness on the lead pattern 3 side, the space for filling the metal material 9 between the through-hole conductor layer 5 and the lead pattern 3 can be increased, so that the bonding strength of the lead member 7 is further improved. Can be made. Furthermore, it is more preferable that the thickness of the through-hole conductor layer 5 gradually increases from the opening side of the through-hole 4 toward the lead-out pattern 3 side. Thereby, the above-described stress concentration relaxation effect can be further enhanced.

  Furthermore, the maximum diameter of glass particles mainly composed of Si present on the surface of the through-hole conductor layer 5 is preferably 100 μm or less. In the ceramic heater according to the present embodiment, Si in the ceramic body 1 is mainly contained on the surface of the through-hole conductor layer 5 and the electrode pad pattern 6 provided on the inner surface of the through-hole 4 during firing. Glass component (particles) to be deposited. When the maximum particle diameter of the glass particles exceeds 100 μm, the metal material 9 and the metal plating layer 8 prevent the metal material 9 and the metal plating layer 8 from coming into contact with the surface of the through-hole conductor layer 5 and the electrode pad pattern 6. There is a possibility that it may become a starting point of a crack generated between the material 9 and the metal plating layer 8 and the through-hole conductor layer 5. Therefore, it is preferable that the maximum particle size is 100 μm or less by a treatment such as blast treatment or ultrasonic cleaning.

The ceramic body 1 is made of various ceramics such as alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, and particularly preferably made of alumina ceramics from the viewpoint of oxidation resistance. Examples of the alumina ceramic include 88 to 95% by weight of Al ₂ O ₃ , ₂ to 7% by weight of SiO ₂ , 0.5 to 3% by weight of CaO, 0.5 to 3% by weight of MgO, and ZrO _2. The composition which consists of 1-3 weight% is mentioned. If the content of Al ₂ O ₃ is less than 88% by weight, the vitreous ratio increases, which may increase migration during energization. On the other hand, when the content of Al ₂ O ₃ exceeds 95% by weight, the amount of glass diffusing into the metal material of the heating resistor 2 embedded in the ceramic body 1 is reduced, and the durability of the ceramic heater is sufficient. There is a risk that it will not be obtained.

  Further, the ceramic body 1 can be exemplified by a cylindrical shape having an outer diameter of about 2 to 20 mm and a length of about 40 to 60 mm. In particular, as a ceramic heater for heating an air-fuel ratio sensor of an automobile, it is preferable that the outer diameter is 2 to 4 mm and the length is 40 to 65 mm because the temperature of the lead member joining portion does not become abnormally high.

Examples of the heating resistor 2 embedded in the ceramic body 1 include those mainly composed of a refractory metal such as W, Mo, and Re. The heating resistor 2 can arbitrarily set the heating position and the resistance value by changing the distance of the folded pattern or changing the pattern line width depending on the application of the ceramic heater.
Next, the manufacturing method of the ceramic heater of this invention is demonstrated with reference to FIG.

First, ceramic sheets 10a and 10b are prepared by forming a ceramic slurry containing alumina as a main component and containing 4 to 12% by weight of SiO ₂ , CaO, MgO, and ZrO ₂ as a sintering aid in a sheet form.

  Next, a heating resistor 2 and a lead pattern 3 are formed on one main surface of the ceramic sheet 10a by using a paste prepared by mixing and kneading a refractory metal such as W, Mo, Re and the like, ceramic raw material, binder, organic solvent and the like. Is formed using a technique such as printing or transfer. The heating resistor 2 can arbitrarily set the heating position and the resistance value by changing the distance of the folded pattern or changing the pattern line width depending on the application of the ceramic heater.

  Next, the through hole 4 is formed in the ceramic sheet 10b, and a conductive material (material of the through hole conductor layer 5) containing at least one of W, Mo, and Re as a main component is formed in the through hole 4 in the through hole 4. Apply to the inner surface. The viscosity of this conductive material is adjusted in advance according to the inner diameter and height of the through hole 4. By adjusting the viscosity, a large amount of the conductive material flows downward in the through hole 4 so that part of the conductive material overflows from the peripheral edge of the lower end of the through hole. In this state, the conductive material on the inner side surface of the through hole 4 and the conductive material that overflows to the outside of the through hole 4 are dried to an appropriate viscosity. Thereby, the thickness of the through-hole conductor layer 5 can be made thicker on the lead-out pattern 3 side than on the opening side of the through-hole 4. The thickness of the through-hole conductor layer 5 can be controlled by the viscosity of the conductive material, the drying conditions, and the like.

Next, the electrode pad pattern 6 is formed on one main surface of the ceramic sheet 10b using a technique such as printing or transfer.
Next, after forming a coat layer having a composition substantially the same as that of the ceramic sheets 10a and 10b on the lead pattern 3 excluding a portion overlapping the heating resistor 2 and the through hole 4, the ceramic sheet 10b and the ceramic sheet 10a are laminated. And pressurizing at a predetermined pressure. At this time, by controlling the pressurizing conditions, the conductive material that is exposed to the outside of the through hole 4 is pushed into the through hole and deformed, so that there is a gap between the through hole conductive layer 5 and the lead pattern 3. Is formed. At this time, by controlling the pressurizing condition, the convex portion 12 in the through hole 4 can be formed by the pressure escaping from the through hole 4. As another method for forming the convex portion 12, there is a method in which pressing and heating are closely adhered in a state where the pattern thickness at the position of the through hole 4 is locally thickened when the extraction pattern 3 is manufactured.

  Since a part of the conductive material goes out of the through hole 4, a portion where the through hole conductor layer 5 overlaps the lead pattern 3 can be surely formed. Can be improved.

  The ceramic sheet 10 formed in this way is wound around the ceramic core 11 using an adhesion liquid and adhered to obtain a cylindrical molded body. Subsequently, the obtained molded body is fired in a reducing atmosphere of about 1500 to 1650 ° C., and the ceramic body 1 is obtained.

  Thereafter, the surface of the electrode pad pattern 6, the through-hole conductor layer 5 in the through-hole 4, the convex portion 12, and the surface of the lead-out pattern 3 are made of a metal such as Ni or Cr by electrolytic plating or electroless plating. A plating layer 8 is formed. The plating thickness is desirably about 1 to 5 μm. When the thickness of the metal plating layer 8 is increased, isolation may occur in the metal plating layer 8. As a method other than plating, the plating layer 8 can be substituted by a method such as sputtering, thermal spraying, and applying and drying a solvent containing submicron noble metal particles.

  Next, a brazing material mainly composed of Au—Cu, Ag, Ag—Cu, or the like is used as the metal material 9, and the electrode pad pattern 6 and the lead member 7 are joined in a reducing atmosphere containing water vapor. In addition, the wettability of the brazing material with respect to the through-hole conductor layer 5, the convex portion 12, the lead pattern 3 and the like can be improved by managing the cleaning of the plated surface and the heating temperature and atmosphere. Thereby, the brazing material can be filled between the through-hole conductor layer 5 and the lead pattern 3 and into the through-hole 4.

  Although not shown, if a plating layer of Au, Cr, Ni or the like is further formed on the surface of the electrode pad pattern 6 and the metal material 9 to 1 to 10 μm, oxidative deterioration of the metal material 9 can be suppressed.

  The ceramic heater of the present invention is not limited to the above-described embodiment, and may be any one that is filled with a metal material between the through-hole conductor layer and the lead pattern, such as a columnar shape, a plate shape, etc. It can be applied to various types of ceramic heaters.

  Moreover, a heating iron can be manufactured by fixing the above-mentioned ceramic heater to a metal tip or the like and connecting it to an electric circuit such as a temperature control device. The heating iron of the present invention can be used for a soldering iron, a hair curler iron, and the like.

  In the above embodiment, in the through-hole conductor layer, a case where a thin region confined to the inner side surface of the through-hole exists between the through-hole conductor layer and the lead pattern is described as an example. In the present invention, the thin region is not limited to the position exemplified in the above embodiment, and may be located at any position of the through-hole conductor layer. As a result, the metal material filled in the constricted thin region exhibits an anchor effect, and the joining strength between the lead member and the ceramic body is dramatically improved. Even after the cooling cycle, the joining strength ( High tensile strength) and excellent durability.

  A ceramic heater was manufactured using the following shapes and materials.

Heater dimensions: φ3mm x Length 55mm
Resistance heating element length: 5mm
Electrode pad pattern: 5mm x 4mm
Through hole diameter: 500 μm
Resistance value: 12-13Ω
Metal plating layer: Ni plating layer having a thickness of 2 to 4 μm Metal material: Ag—Cu brazing material or Ag—Sn solder lead member: φ0.8 mm × length 20 mm
Below, the manufacturing procedure of this ceramic heater is shown.

First, a ceramic green sheet having Al ₂ O ₃ as a main component and SiO ₂ , CaO, MgO, and ZrO ₂ adjusted so as to be within 10% by weight in total is prepared. The heating resistor 2 was printed by a screen printing method using a paste to be printed, and the drawing pattern 3 was printed by a screen printing method using a paste containing W as a main component.

  Further, the through hole 4 was provided in another ceramic green sheet, and the through hole conductor layer 5 was formed using a paste mainly composed of W. At this time, the viscosity and drying conditions of the paste forming the through-hole conductor layer 5 were adjusted, and a sample having a thickness of 3 to 27% of the through-hole conductor layer 5 with respect to the through-hole diameter was produced. In addition, a sample having a thick lower part of the through-hole conductor layer 5 was produced in the same manner. Thereafter, the electrode pad pattern 6 was printed on the through hole 4 by a screen printing method using a paste containing W as a main component.

Next, after a coating layer composed of substantially the same components as the ceramic green sheet is formed on the surface of the heating resistor 2 on the surface on which the heating resistor 2 has been printed in advance, the coating layer is sufficiently dried. An adhesion liquid in which ceramics having the same composition were dispersed was applied, and was pressed and heated and adhered to the ceramic green sheet provided with the through holes 4 and the electrode pad pattern 6. Here, the convex shape 12 in the through hole 4 was formed by pressurizing at a pressure about 1.5 times the conventional pressurizing condition (load of about 3 kgf / cm ² ).

  Then, an adhesion liquid in which ceramics having substantially the same composition as the ceramic green sheet is dispersed is applied to the back surface of the adhered sheet, and is adhered to the periphery of the ceramic core and fired in a reducing atmosphere at 1500 to 1600 ° C. did.

  Thereafter, the through hole 4 and the electrode pad pattern 6 were blasted to remove the glass layer deposited by firing, and at the same time, the surface roughness was adjusted to 0.7 to 5 μm.

  Next, instead of the previously removed glass particles, glass particles having an arbitrary particle size were placed in the through holes.

  Next, a plating layer 8 was provided by electrolytic plating, and a lead member was joined using Ag—Cu solder and Ag—Sn solder as the metal material 9 to obtain a ceramic heater sample.

Then, the temperature of the electrode pad pattern portion is set to 10 in a constant temperature bath set to a temperature half the melting point of the metal material 9 (about 100 ° C. for Ag—Sn solder, about 400 ° C. for Ag—Cu solder). The sample was held for 4 minutes and subjected to 4000 cycles of forced air cooling with air at 25 ° C., the tensile strength of the lead member after the test was measured, and the determination was made that the tensile strength of the lead member was 20 N or more.
These results are shown in Table 1.

In addition, the tensile strength measuring method is shown below.
Test method: A heater is fixed to a tensile tester, and the load is measured when the lead is pulled vertically with a load cell at a speed of 32 mm / min and cut.
Thickness measurement method: The heater after the test was embedded in a resin, polished, and the thickness was measured with a microscope from a cross section.
Surface roughness: Surface roughness (Ra) was measured with a non-contact type three-dimensional surface roughness measuring device.

  From the same table, sample No. No. 1 has a weak tensile strength of 6N, and the durability of the lead joint is extremely low. This is because the anchor effect cannot be used because the metal material 9 cannot be filled between the lead pattern 3 and the through-hole conductor layer 5.

  On the other hand, sample No. 1 in which the metal material 9 is filled between the lead pattern 3 and the through-hole conductor layer 5 is used. For No. 2, the tensile strength was 22N, and the durability of the lead joint was good.

  Furthermore, in sample No. 2 using solder for the metal material 9, corrosion of the solder occurred in the cooling cycle, but in sample No. 3 using brazing material for the metal material 9, the durability of the lead joint portion is further good. It became a result.

  Further, the sample No. 8 filled with the metal material 9 through the conductor layer 5 and the metal plating layer 8 on the surface 3 of the lead-out pattern 3 is used. No. 4 improved the paintability of the metal material 9, and the sample No. From 2 to 3, the durability of the lead joint was good.

  Sample No. 5 is Sample No. From 2 to 4, since the value of the tensile strength after the durability test is high, forming the convex shape 12 at the bottom of the through hole is a desirable result in the durability of the lead joint.

  Furthermore, sample Nos. 1 and 4 having surface roughness Ra of 1 μm or more of the through-hole conductor layer 5 and the electrode pad pattern 6 were measured. 6-8 and sample no. From comparison with 2 to 5, the surface roughness of the through-hole conductor layer 5 and the electrode pad pattern 6 is preferably Ra 1 μm or more in view of durability of the lead joint portion. In particular, the surface roughness is preferably Ra 5 μm.

  Sample No. 10-13 and sample no. From the comparison of 8 and 9, it is found that the thickness of the conductor layer 5 provided on the inner surface of the through hole is preferably within 5% to 25% of the diameter of the through hole 4 because of the durability of the lead joint. did. . In particular, the thickness of the conductor layer 5 provided on the inner surface of the through hole is preferably 20% of the diameter of the through hole 4.

  Furthermore, sample no. 14-16 and sample no. From the comparison of Nos. 12 and 13, it is excellent in durability of the lead joint that the maximum diameter of the glass particles mainly composed of Si remaining on the surface of the through-hole conductor layer provided on the inner surface of the through-hole is 100 μm or less. I understood.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a ceramic heater according to the present invention, where (a) is a perspective view and (b) is a partial cross-sectional view around an electrode pad pattern. (A) is sectional drawing which shows the through-hole part in the ceramic heater of this invention, (b) is a top view which shows the top view of the figure (a). It is a perspective view explaining the manufacturing method of the ceramic heater of this invention. (A) is a perspective view which shows the conventional ceramic heater, (b) is a disassembled perspective view of the ceramic body of the figure (a), (c) is a fragmentary sectional view around an electrode pad pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 21 ... Ceramic body 2, 22 ... Heating resistor 3, 23 ... Lead-out pattern 4, 24 ... Through-hole 5, 25 ... Through-hole conductor layer 6, 26 ... Electrode Pad pattern 7, 27 ... Lead member 8, 28 ... Plating layer 9, 29 ... Metal material 10, 10a, 10b, 30, 30a, 30b ... Ceramic green sheet 11, 31 ... Ceramic Core material 12 ... Convex shape

Claims (13)

A heating resistor, a lead pattern connected to the heat generating resistor, a ceramic body in which the heat generating resistor and the lead pattern are embedded, and a through hole reaching the lead pattern is formed, and at least an inner surface of the through hole A through-hole conductor layer formed on the electrode body, an electrode pad pattern electrically connected to the through-hole conductor layer and formed on the surface of the ceramic body, and a lead member electrically connected to the electrode pad pattern; In a ceramic heater having
The through-hole conductor layer has a thin region confined to the inner surface side of the through-hole, the thin region is filled with a metal material, and the metal material is bonded to the lead member. A ceramic heater characterized by 2. The ceramic heater according to claim 1, wherein the thin region is located at a position closer to the lead pattern than the maximum thickness portion of the through-hole conductor layer and in the vicinity of the maximum thickness portion. A heating resistor, a lead pattern connected to the heat generating resistor, a ceramic body in which the heat generating resistor and the lead pattern are embedded, and a through hole reaching the lead pattern is formed, and at least an inner surface of the through hole A through-hole conductor layer formed on the electrode body, an electrode pad pattern electrically connected to the through-hole conductor layer and formed on the surface of the ceramic body, and a lead member electrically connected to the electrode pad pattern; In a ceramic heater having
A ceramic heater, wherein a metal material is filled between the through-hole conductor layer and the lead pattern, and the metal material is bonded to the lead member. The ceramic heater according to claim 1, wherein the metal material is filled in the through hole and joined to the lead member. The ceramic heater according to claim 1, wherein the metal material is a brazing material. A metal plating layer is formed on the surface of the through-hole conductor layer and the surface of the lead-out electrode pattern in the portion where the through-hole is formed, and the metal plating layer and the lead-out pattern on the surface of the through-hole conductor layer The ceramic heater according to claim 1, wherein the metal material is filled between the metal plating layer on the surface of the ceramic heater. The ceramic heater according to any one of claims 1 to 6, wherein the lead-out pattern has a portion in which the through hole is formed bulges toward the through hole. 8. The surface roughness (Ra) of the electrode pad pattern and the through-hole conductor layer is 1 μm or more, and the lead member is fixed on the electrode pad pattern using a brazing material. The ceramic heater according to crab. 9. The ceramic heater according to claim 1, wherein a thickness of the through-hole conductor layer is 5% to 25% of a through-hole diameter. 10. The ceramic heater according to claim 1, wherein a thickness of the through-hole conductor layer is thicker on the drawing pattern side than on an opening side of the through-hole. The ceramic heater according to any one of claims 1 to 10, wherein the through-hole conductor layer has a thickness that gradually increases from the opening side of the through-hole toward the lead-out pattern side. The ceramic heater according to any one of claims 1 to 11, wherein the maximum diameter of glass particles mainly composed of Si present on the surface of the through-hole conductor layer is 100 µm or less. A heating iron using the ceramic heater according to claim 1 as a heating means.

Images