JPWO2012114818A1 - Ceramic electronic component and method for designing ceramic electronic component - Google Patents

Abstract

The present invention relates to a ceramic electronic component in which a crack does not occur at a portion where an external electrode and solder are joined or a crack is gradually increased even when a heating / cooling temperature cycle test is performed, and a ceramic electronic component Provide a design method. The present invention is a ceramic electronic component 10 including a ceramic sintered body 1 and an external electrode 2 formed outside the ceramic sintered body 1 and containing a conductive resin 20. The external electrode 2 is composed of the base electrode 3, the conductive resin 20, and the plating 6, and has a linear expansion coefficient on the surface of the external electrode 2 that is joined to the mounting substrate (another substrate) by solder, and the surface of the solder. The linear expansion coefficient agrees.

Description

  The present invention relates to a ceramic electronic component in which external electrodes are formed on the outside of a ceramic sintered body, and a method for designing the ceramic electronic component.

  The ceramic electronic component disclosed in Patent Document 1 includes a ceramic sintered body and an external electrode formed on the outside of the ceramic sintered body, and the external electrode buffers an external impact or thermal expansion difference. It is made of a conductive resin that absorbs. Further, in Patent Document 1, a ceramic electronic component is bonded to a mounting substrate with solder, and the ceramic electronic component bonded to the mounting substrate is repeatedly dropped from a predetermined height to evaluate the occurrence rate of cracks in the ceramic electronic component. Yes.

JP 2006-295076 A

  In the ceramic electronic component disclosed in Patent Document 1, the ceramic electronic component is dropped from a predetermined height by reducing the Young's modulus in the conductive resin forming the external electrode (softening the conductive resin). Even in this case, it is shown that the rate of occurrence of cracks in the ceramic electronic component is lowered. However, when the heating / cooling temperature cycle test is performed on the ceramic electronic component disclosed in Patent Document 1, even when the Young's modulus of the conductive resin forming the external electrode is reduced, the external electrode and the solder are Cracks are generated in the bonded portions, and the generated cracks become larger as the number of cycles increases, so there is a problem that the reliability of bonding between the external electrode and the solder is low.

  The present invention has been made in view of such circumstances, and even when a heating / cooling temperature cycle test is performed, a crack does not occur in the portion where the external electrode and the solder are joined, or the generated crack is moderate. It is an object of the present invention to provide a ceramic electronic component that is large and a method for designing the ceramic electronic component.

  In order to achieve the above object, a ceramic electronic component according to the present invention is a ceramic electronic component comprising a ceramic sintered body and an external electrode formed outside the ceramic sintered body and containing a conductive resin, The linear expansion coefficient on the surface of the external electrode bonded to another substrate by soldering and the linear expansion coefficient on the surface of the solder match.

  In the above configuration, since the linear expansion coefficient on the surface of the external electrode containing the conductive resin and joined to the other substrate by solder matches the linear expansion coefficient on the surface of the solder, the heating / cooling temperature cycle test is performed. If it is performed, the surface of the external electrode joined by soldering with the other substrate is also repeatedly subjected to thermal expansion and thermal contraction, following the surface of the solder that repeats thermal expansion and thermal contraction. Since cracks do not occur at the portion where the solder is joined, or even if cracks occur, the number of cycles increases gradually, so the reliability of joining between the external electrode and the solder increases.

  In addition, the ceramic electronic component according to the present invention is the external electrode bonded to another substrate by soldering when the Young's modulus of the conductive resin bonded to another substrate by soldering is in the range of 1 GPa or more and 19 GPa or less. It is preferable that the coefficient of linear expansion on the surface of is in the range of 17 ppm / K or more and 24 ppm / K or less.

  In the above configuration, the line on the surface of the external electrode to be joined to the other substrate by soldering in the range where the Young's modulus of the conductive resin contained in the external electrode to be joined to the other substrate by soldering is 1 GPa or more and 19 GPa or less. Since the expansion coefficient is in the range of 17 ppm / K or more and 24 ppm / K or less, when the heating / cooling temperature cycle test is performed, the solder surface that repeats thermal expansion and thermal contraction is followed to another substrate and solder. In the same manner, the surface of the external electrode to be joined can be repeatedly expanded and contracted.

  Next, in order to achieve the above object, a ceramic electronic component design method according to the present invention includes a ceramic sintered body and a ceramic formed on the outside of the ceramic sintered body and including an external electrode containing a conductive resin. A method for designing an electronic component, in which the linear expansion coefficient on the surface of the external electrode bonded to another substrate by solder matches the linear expansion coefficient on the surface of the solder. It is characterized by determining Young's modulus and linear expansion coefficient.

  In the above configuration, the Young's modulus in the conductive resin and the linear expansion coefficient on the surface of the external electrode that includes the conductive resin and is joined to the other substrate by solder match the linear expansion coefficient on the surface of the solder. Since the coefficient of linear expansion is determined, when the heating / cooling temperature cycle test is performed, the surface of the external electrode joined by soldering to another substrate is similarly tracked following the surface of the solder that repeats thermal expansion and contraction. By repeating thermal expansion and contraction, cracks do not occur at the joint between the external electrode and the solder, or even if a crack occurs, the crack gradually increases with the increase in the number of cycles. A highly reliable ceramic electronic component can be designed.

  In the ceramic electronic component according to the present invention, since the linear expansion coefficient on the surface of the external electrode containing the conductive resin and joined to the other substrate by solder matches the linear expansion coefficient on the surface of the solder, When performing a cooling temperature cycle test, follow the surface of the solder that repeats thermal expansion and contraction, and repeat the thermal expansion and contraction of the surface of the external electrode that is bonded to the other substrate by soldering. As a result, no crack is generated at the portion where the external electrode and the solder are joined, or even if a crack occurs, it gradually increases as the number of cycles increases, so that the reliability of the joint between the external electrode and the solder is increased.

  In the design method of the ceramic electronic component according to the present invention, the linear expansion coefficient on the surface of the external electrode including the conductive resin and joined to the other substrate by soldering is matched with the linear expansion coefficient on the surface of the solder. Since the Young's modulus and coefficient of linear expansion of the conductive resin are determined, when the heating / cooling temperature cycle test is performed, the solder is repeatedly bonded with other substrates by following the surface of the solder that repeats thermal expansion and contraction. Similarly, the surface of the external electrode that repeats thermal expansion and contraction does not cause cracks at the joint between the external electrode and solder, or even if cracks occur, it gradually increases as the number of cycles increases. It is possible to design a ceramic electronic component with high reliability of bonding between the external electrode and the solder.

It is the schematic which shows the structure of the ceramic electronic component which concerns on embodiment of this invention. It is a graph which shows the relationship between the linear expansion coefficient in the surface of the external electrode calculated | required using the simulation method, and the linear expansion coefficient of conductive resin. It is the schematic which shows the simulation result at the time of performing a heating-cooling temperature cycle test using the simulation method with respect to the ceramic electronic component which concerns on embodiment of this invention. It is the schematic which shows the simulation result at the time of performing a heating-cooling temperature cycle test with respect to another ceramic electronic component which concerns on embodiment of this invention using a simulation method. It is a graph which shows the relationship between the linear expansion coefficient in the surface of an external electrode, and the cycle number at which the part which an external electrode and a solder join fracture when a heating / cooling temperature cycle test is performed using a simulation method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration of a ceramic electronic component according to an embodiment of the present invention. As shown in FIG. 1, the ceramic electronic component 10 includes a ceramic sintered body 1 and an external electrode 2 formed outside the ceramic sintered body 1. The ceramic electronic component 10 is, for example, a chip type multilayer capacitor, a chip resistor or the like.

  The ceramic sintered body 1 is made of dielectric ceramics such as barium titanate and has an internal electrode (not shown) formed therein. The internal electrodes are arranged so as to overlap with each other through the ceramic layer, and a part is exposed from the side surface of the ceramic sintered body 1.

  The external electrode 2 is formed outside the ceramic sintered body 1 where a part of the internal electrode is exposed from the side surface, and is electrically connected to the internal electrode. The external electrode 2 includes a conductive resin 20 and is formed to have a thickness of 20 to 150 μm. The conductive resin 20 is formed by dispersing conductive powders such as Ag and Cu in a thermosetting resin such as an epoxy resin, a phenol resin, and an acrylic resin. In the ceramic electronic component 10, the base electrode 3 is formed between the surface of the ceramic sintered body 1 and the conductive resin 20 in order to firmly adhere the external electrode 2 formed outside the ceramic sintered body 1. It is. The base electrode 3 is formed by applying and baking a conductive paste containing a metal powder such as Ag, Ag-Pd, or Cu. A plating 6 is formed on the outside of the conductive resin 20 by electrolytic plating. Examples of the plating 6 include Ni plating, Sn plating, and solder plating. The external electrode 2 in the present embodiment is composed of a base electrode 3, a conductive resin 20, and a plating 6.

  The ceramic electronic component 10 is used by mounting the external electrode 2 on a mounting substrate (other substrate) (not shown) with solder. Therefore, the ceramic electronic component 10 mounted on the mounting substrate is subjected to, for example, a heating / cooling temperature cycle test as a reliability test in order to verify the reliability of bonding between the external electrode 2 and the solder 4. In the heating / cooling temperature cycle test, for example, the ceramic electronic component 10 is placed in a bath having a temperature of −40 ° C. for 30 minutes and then placed in a bath having a temperature of 125 ° C. for 30 minutes. It is a test. When a heating / cooling temperature cycle test is performed on a conventional ceramic electronic component, even when the conductive resin forming the external electrode is reduced to make the conductive resin soft, the external electrode and the solder are joined. Cracks were generated in the portions, and the generated cracks became larger as the number of cycles increased, and the reliability of bonding between the external electrode and the solder was low.

  Therefore, for the ceramic electronic component 10 according to the embodiment of the present invention, the linear expansion coefficient on the surface of the external electrode 2 joined with the mounting substrate and solder is matched with the linear expansion coefficient on the surface of the solder, When the heating / cooling temperature cycle test is performed, the surface of the external electrode 2 joined by soldering is similarly subjected to thermal expansion and thermal contraction following the surface of the solder that repeats thermal expansion and thermal contraction. By repeating, it was considered that the reliability of bonding between the external electrode 2 and the solder can be increased. That is, the physical properties (Young's modulus, linear expansion coefficient, etc.) of the conductive resin 20 so that the linear expansion coefficient on the surface of the external electrode 2 bonded to the mounting substrate by solder matches the linear expansion coefficient on the surface of the solder. The ceramic electronic component 10 is designed. Note that the linear expansion coefficient on the surface of the external electrode 2 joined to the mounting substrate by solder does not match the linear expansion coefficient of the conductive resin 20 included in the external electrode 2, and the shape of the external electrode 2, the mounting substrate and the solder It varies depending on the position to be joined.

  Therefore, the linear expansion coefficient on the surface of the external electrode 2 bonded to the mounting substrate by soldering is obtained by actually creating the ceramic electronic component 10 and using the digital image correlation method or the like for the created ceramic electronic component 10. Specifically, a change in the distance between two points on the surface of the external electrode 2 (change from L1 to L2) when the ceramic electronic component 10 is changed by the temperature ΔT using a digital image correlation method or the like. ) And the linear expansion coefficient on the surface of the external electrode 2 to be joined to the mounting substrate by soldering is obtained from the value of (L2−L1) / ΔT / L1. Here, the digital image correlation method refers to image data obtained by photographing a ceramic electronic component 10 before and after forming a random pattern on the surface of the external electrode 2 of the ceramic electronic component 10 and changing the temperature by ΔT. From this, the amount of thermal deformation is measured by tracking a random pattern formed on the surface, and the coefficient of linear expansion on the surface of the external electrode 2 to be joined to the mounting substrate by soldering is determined based on the measured amount of thermal deformation It is.

  Further, there is a simulation method as a method for obtaining the linear expansion coefficient on the surface of the external electrode 2 to be joined to the mounting substrate by soldering without actually creating the ceramic electronic component 10. Also in the simulation method, when the ceramic electronic component 10 is changed by the temperature ΔT, a change in the distance between any two points on the surface of the external electrode 2 (change from L1 to L2) is measured, and (L2-L1 ) / ΔT / L1 to obtain the linear expansion coefficient on the surface of the external electrode 2 to be joined to the mounting substrate by soldering.

  The simulation method is a method of obtaining a linear expansion coefficient on the surface of the external electrode 2 to be joined to the mounting substrate by soldering by performing structural analysis of the ceramic electronic component 10 using a finite element method. Further, in the simulation method, when a finite element method model having a structure in which the ceramic electronic component 10 is bonded to a mounting substrate with solder is created and a heating / cooling temperature cycle test is performed on the created finite element method model, The resulting inelastic strain amplitude Δε is obtained. Furthermore, apply the Manson-Coffin rule and linear damage law to the obtained inelastic strain amplitude Δε to calculate the damage accumulated in the solder, and delete the element that has reached the predetermined damage as a crack has occurred. Thus, a simulation of the occurrence of cracks in the portion where the external electrode 2 and the solder are joined is performed. Note that the number of rupture cycles calculated in the simulation can be regarded as the actual number of rupture cycles by multiplying the number of rupture cycles of the actually measured sample by a correction coefficient.

  In the following description, a case will be described in which the linear expansion coefficient on the surface of the external electrode 2 bonded to the mounting substrate by soldering is obtained using a simulation method. Note that the present invention is not limited to the case of obtaining the linear expansion coefficient on the surface of the external electrode 2 joined to the mounting substrate by soldering. FIG. 2 is a graph showing the relationship between the linear expansion coefficient on the surface of the external electrode 2 obtained using the simulation method and the linear expansion coefficient of the conductive resin 20. In FIG. 2, when the linear expansion coefficient of the conductive resin 20 is changed in the range of 20 to 300 ppm / K, the linear expansion coefficient on the surface of the external electrode 2 joined to the mounting substrate by soldering is 12 to 34 ppm / K. It varies in the range. Here, when the linear expansion coefficient on the surface of the solder is 26 ppm / K and the linear expansion coefficient of the conductive resin 20 is 200 ppm / K, the linear expansion coefficient on the surface of the external electrode 2 joined with the mounting substrate by soldering is 26 ppm / K, which coincides with the linear expansion coefficient on the solder surface. The degree of coincidence of the linear expansion coefficients may be within a range of ± 30%. For example, when the linear expansion coefficient on the surface of the solder is 26 ppm / K, the linear expansion coefficient on the surface of the external electrode 2 may be designed to be in the range of 18 to 34 ppm / K. By including the conductive resin 20 in the external electrode 2, the value of the linear expansion coefficient can be designed intentionally.

  Next, assuming that the linear expansion coefficient of the conductive resin 20 is 200 ppm / K, the linear expansion coefficient (26 ppm / K) on the surface of the external electrode 2 bonded to the mounting substrate (other substrate) by solder is the solder linear expansion. The results when the heating / cooling temperature cycle test is performed on the ceramic electronic component 10 that matches the coefficient will be described using a simulation method. FIG. 3 is a schematic diagram illustrating a simulation result when a heating / cooling temperature cycle test is performed on the ceramic electronic component 10 according to the embodiment of the present invention using a simulation method. The simulation result shown in FIG. 3A shows the simulation result when the ceramic electronic component 10 is subjected to a heating / cooling temperature cycle test of 3814 cycles. The ceramic electronic component 10 is a wire on the surface of the external electrode 2 bonded to the mounting substrate 5 and the solder 4 when the Young's modulus of the conductive resin 20 is 1 GPa and the linear expansion coefficient of the conductive resin 20 is 200 ppm / K. The expansion coefficient coincides with the linear expansion coefficient on the surface of the solder 4. In the simulation results, a mesh used in the finite element method is illustrated for the ceramic electronic component 10 to which the external electrode 2 is bonded by the mounting substrate 5 and the solder 4, and a heating / cooling temperature cycle test of 3814 cycles is performed. Even so, there is no change in the mesh of the portion 40 where the external electrode 2 and the solder 4 are joined, and no crack is generated in the direction indicated by the arrow.

  On the other hand, the simulation result shown in FIG. 3B shows the simulation result when the heating / cooling temperature cycle test of 3950 cycles is performed on the ceramic electronic component 10. The ceramic electronic component 10 is a wire on the surface of the external electrode 2 bonded to the mounting substrate 5 and the solder 4 when the Young's modulus of the conductive resin 20 is 10 GPa and the linear expansion coefficient of the conductive resin 20 is 26 ppm / K. The expansion coefficient does not match the linear expansion coefficient on the surface of the solder 4. In the simulation results, a mesh used in the finite element method is illustrated for the ceramic electronic component 10 to which the external electrode 2 is bonded by the mounting substrate 5 and the solder 4, and a heating and cooling temperature cycle test of 3950 cycles is performed. Further, there is a change in the mesh of the portion 40 where the external electrode 2 and the solder 4 are joined, and a crack 41 is generated in the direction indicated by the arrow.

  In addition, the ceramic electronic component 10 in which the linear expansion coefficient on the surface of the external electrode 2 bonded to the mounting substrate 5 and the solder 4 matches the linear expansion coefficient on the surface of the solder 4 is bonded to the mounting substrate 5 and the solder 4. The linear expansion coefficient on the surface of the external electrode 2 to be applied is gradually increased with an increase in the number of cycles even if the crack 41 occurs, compared with the ceramic electronic component 10 that does not match the linear expansion coefficient on the surface of the solder 4. The ceramic electronic component 10 is designed so that the linear expansion coefficient of the surface of the external electrode 2 joined by the solder 4 with the mounting substrate 5 of the ceramic electronic component 10 matches the linear expansion coefficient of the interface (surface) of the solder 4. As a result, the reliability of bonding between the external electrode 2 and the solder 4 is increased.

  Next, FIG. 4 is a schematic diagram illustrating a simulation result when a heating / cooling temperature cycle test is performed on another ceramic electronic component 11 according to the embodiment of the present invention using a simulation method. The simulation result shown in FIG. 4 shows the simulation result when a 3721 cycle heating / cooling temperature cycle test is performed on the ceramic electronic component 11. The ceramic electronic component 11 is an external electrode bonded to the mounting substrate (other substrate) 5 by solder 4 when the Young's modulus of the conductive resin 20 is 19 GPa and the linear expansion coefficient of the conductive resin 20 is 177 ppm / K. The linear expansion coefficient on the surface of 2 coincides with the linear expansion coefficient on the surface of the solder 4. In the simulation results, the mesh used in the finite element method is illustrated in the ceramic electronic component 11 in which the external electrode 2 is joined by the mounting substrate 5 and the solder 4, and a heating / cooling temperature cycle test of 3721 cycles is performed. Even so, there is no change in the mesh of the portion 40 where the external electrode 2 and the solder 4 are joined, and the crack 41 does not occur in the direction indicated by the arrow.

  FIG. 5 shows the linear expansion coefficient on the surface of the external electrode 2 and the number of cycles at which the portion 40 where the external electrode 2 and the solder 4 are joined breaks when the heating / cooling temperature cycle test is performed using the simulation method. It is a graph which shows a relationship. FIG. 5 shows a case where the heating / cooling temperature cycle test is performed on the ceramic electronic component 11 having the Young's modulus of the conductive resin 20 of 1 GPa and the case of the ceramic electronic component 10 having the Young's modulus of the conductive resin 20 of 19 GPa. The case where the heating / cooling temperature cycle test is performed is shown. When the heating / cooling temperature cycle test is performed on the ceramic electronic component 11 having a Young's modulus of 1 GPa of the conductive resin 20, the linear expansion coefficient on the surface of the external electrode 2 is changed in the range of 11 to 47 ppm / K. The number of cycles at which the portion 40 where the external electrode 2 and the solder 4 are joined is broken by the crack 41 is shown. When the coefficient of linear expansion on the surface of the external electrode 2 is changed in the range of 14 to 29 ppm / K, the number of cycles becomes 12,000 cycles or more, and the number of cycles with respect to the change in the coefficient of linear expansion on the surface of the external electrode 2 is high. . When the heating / cooling temperature cycle test was performed on the ceramic electronic component 10 having a Young's modulus of 19 GPa of the conductive resin 20, the linear expansion coefficient on the surface of the external electrode 2 was changed in the range of 10 to 34 ppm / K. The number of cycles at which the portion 40 where the external electrode 2 and the solder 4 are joined is broken by the crack 41 is shown. When the linear expansion coefficient on the surface of the external electrode 2 is changed in the range of 17 to 24 ppm / K, the number of cycles becomes 11,000 or more, and the number of cycles corresponding to the change in the linear expansion coefficient on the surface of the external electrode 2 is high. .

  As the Young's modulus of the conductive resin 20 when the heating / cooling temperature cycle test is performed, the number of cycles in which the portion 40 where the external electrode 2 and the solder 4 are joined breaks by the crack 41 becomes 11000 cycles or more. The range in which the linear expansion coefficient on the surface of the conductive resin 20 is changed is widened. Therefore, the external electrode 2 and the solder until the number of cycles when the heating / cooling temperature cycle test is performed on the ceramic electronic components 10 and 11 having a Young's modulus of the conductive resin 20 of 1 GPa or more and 19 GPa or less reaches 11000 cycles or more. In order to prevent the portion 40 joined to 4 from being broken by the crack 41, the range of changing the linear expansion coefficient on the surface of the external electrode 2 joined by the mounting substrate 5 and the solder 4 is 17 ppm / K or more, It is necessary to make it 24 ppm / K or less.

  The conductive resin 20 formed by dispersing conductive powders such as Ag and Cu in a thermosetting resin such as an epoxy resin, a phenol resin, and an acrylic resin is, for example, an imidazole catalyst (0.4% by weight). , Novolak phenol (1.6 wt%), bisphenol A type epoxy (6.0 wt%), polycarboxylic acid dispersant (1.0 wt%), Ag powder (91.0 wt%) It is. Therefore, among the components of the conductive resin 20, by adjusting the amount of novolac phenol and bisphenol A type epoxy while keeping the ratio of novolak phenol and bisphenol A type epoxy constant, the Young's modulus of the conductive resin 20, The linear expansion coefficient can be changed.

  As described above, in the ceramic electronic components 10 and 11 according to the embodiment of the present invention, the external electrode 2 includes the conductive resin 20, and the surface of the external electrode 2 that is joined to the mounting substrate 5 by the solder 4. Since the Young's modulus and the linear expansion coefficient in the conductive resin 20 are determined so that the linear expansion coefficient at the surface of the solder 4 matches the linear expansion coefficient at the surface of the solder 4, By following the surface of the solder 4 that repeats expansion and contraction, the surface of the external electrode 2 joined by the mounting substrate 5 and the solder 4 repeats thermal expansion and contraction in the same manner. Since the crack 41 does not occur in the portion 40 where the solder 4 is bonded, or even if the crack 41 is generated, it gradually increases as the number of cycles increases, so the reliability of bonding between the external electrode 2 and the solder 4 is high. It made.

DESCRIPTION OF SYMBOLS 1 Ceramic sintered body 2 External electrode 3 Base electrode 4 Solder 5 Mounting board 6 Plating 10, 11 Ceramic electronic component 20 Conductive resin 41 Crack

In order to achieve the above object, a ceramic electronic component according to the present invention is a ceramic electronic component comprising a ceramic sintered body and an external electrode formed outside the ceramic sintered body and containing a conductive resin, The coefficient of linear expansion on the surface of the external electrode bonded to another substrate by solder matches the coefficient of linear expansion on the surface of the solder, and the Young of the conductive resin bonded to the other substrate by solder. The linear expansion coefficient on the surface of the external electrode to be joined to another substrate by soldering is in a range of 17 ppm / K or more and 24 ppm / K or less in a rate of 1 GPa or more and 19 GPa or less. .

In addition, the coefficient of linear expansion on the surface of the external electrode to be joined to the other substrate by soldering is within a range where the Young's modulus of the conductive resin contained in the external electrode to be joined to the other substrate by soldering is 1 GPa or more and 19 GPa or less. However, in the range of 17 ppm / K or more and 24 ppm / K or less, when the heating / cooling temperature cycle test is performed, the solder surface that repeats thermal expansion and contraction is followed and soldered to another substrate. Similarly, the surface of the external electrode can repeat thermal expansion and thermal contraction.

Next, in order to achieve the above object, a ceramic electronic component design method according to the present invention includes a ceramic sintered body and a ceramic formed on the outside of the ceramic sintered body and including an external electrode containing a conductive resin. A method for designing an electronic component, in which the linear expansion coefficient on the surface of the external electrode bonded to another substrate by solder matches the linear expansion coefficient on the surface of the solder. In determining the Young's modulus and the coefficient of linear expansion, the external electrode is bonded to another substrate with solder when the Young's modulus of the conductive resin bonded to the other substrate with solder is in the range of 1 GPa or more and 19 GPa or less. The linear expansion coefficient on the surface of is in the range of 17 ppm / K or more and 24 ppm / K or less .

In the above configuration, the Young's modulus in the conductive resin and the linear expansion coefficient on the surface of the external electrode that includes the conductive resin and is joined to the other substrate by solder match the linear expansion coefficient on the surface of the solder. Since the coefficient of linear expansion is determined, when the heating / cooling temperature cycle test is performed, the surface of the external electrode joined by soldering to another substrate is similarly tracked following the surface of the solder that repeats thermal expansion and contraction. By repeating thermal expansion and contraction, cracks do not occur at the joint between the external electrode and the solder, or even if a crack occurs, the crack gradually increases with the increase in the number of cycles. A highly reliable ceramic electronic component can be designed.
In addition, the coefficient of linear expansion on the surface of the external electrode to be joined to the other substrate by soldering is within a range where the Young's modulus of the conductive resin contained in the external electrode to be joined to the other substrate by soldering is 1 GPa or more and 19 GPa or less. However, in the range of 17 ppm / K or more and 24 ppm / K or less, when the heating / cooling temperature cycle test is performed, the solder surface that repeats thermal expansion and contraction is followed and soldered to another substrate. Similarly, the surface of the external electrode can repeat thermal expansion and thermal contraction.

In the ceramic electronic component according to the present invention, since the linear expansion coefficient on the surface of the external electrode containing the conductive resin and joined to the other substrate by solder matches the linear expansion coefficient on the surface of the solder, When performing a cooling temperature cycle test, follow the surface of the solder that repeats thermal expansion and contraction, and repeat the thermal expansion and contraction of the surface of the external electrode that is bonded to the other substrate by soldering. As a result, no crack is generated at the portion where the external electrode and the solder are joined, or even if a crack occurs, it gradually increases as the number of cycles increases, so that the reliability of the joint between the external electrode and the solder is increased.
In addition, the coefficient of linear expansion on the surface of the external electrode to be joined to the other substrate by soldering is within a range where the Young's modulus of the conductive resin contained in the external electrode to be joined to the other substrate by soldering is 1 GPa or more and 19 GPa or less. However, in the range of 17 ppm / K or more and 24 ppm / K or less, when the heating / cooling temperature cycle test is performed, the solder surface that repeats thermal expansion and contraction is followed and soldered to another substrate. Similarly, the surface of the external electrode can repeat thermal expansion and thermal contraction.

In the design method of the ceramic electronic component according to the present invention, the linear expansion coefficient on the surface of the external electrode including the conductive resin and joined to the other substrate by soldering is matched with the linear expansion coefficient on the surface of the solder. Since the Young's modulus and coefficient of linear expansion of the conductive resin are determined, when the heating / cooling temperature cycle test is performed, the solder is repeatedly bonded with other substrates by following the surface of the solder that repeats thermal expansion and contraction. Similarly, the surface of the external electrode that repeats thermal expansion and contraction does not cause cracks at the joint between the external electrode and solder, or even if cracks occur, it gradually increases as the number of cycles increases. It is possible to design a ceramic electronic component with high reliability of bonding between the external electrode and the solder.
In addition, the coefficient of linear expansion on the surface of the external electrode to be joined to the other substrate by soldering is within a range where the Young's modulus of the conductive resin contained in the external electrode to be joined to the other substrate by soldering is 1 GPa or more and 19 GPa or less. However, in the range of 17 ppm / K or more and 24 ppm / K or less, when the heating / cooling temperature cycle test is performed, the solder surface that repeats thermal expansion and contraction is followed and soldered to another substrate. Similarly, the surface of the external electrode can repeat thermal expansion and thermal contraction.

Claims (3)

Ceramic sintered body,
A ceramic electronic component comprising an external electrode formed on the outside of the ceramic sintered body and containing a conductive resin,
A ceramic electronic component, characterized in that a linear expansion coefficient on a surface of the external electrode bonded to another substrate by solder and a linear expansion coefficient on the surface of the solder coincide with each other.   When the Young's modulus of the conductive resin bonded to another substrate by solder is in the range of 1 GPa or more and 19 GPa or less, the linear expansion coefficient on the surface of the external electrode bonded by soldering to another substrate is 17 ppm / K. The ceramic electronic component according to claim 1, wherein the range is 24 ppm / K or less. Ceramic sintered body,
A method of designing a ceramic electronic component comprising an external electrode formed on the outside of the ceramic sintered body and including a conductive resin,
Determining the Young's modulus and linear expansion coefficient of the conductive resin so that the linear expansion coefficient on the surface of the external electrode bonded to another substrate by solder matches the linear expansion coefficient on the surface of the solder; A method for designing a ceramic electronic component.