JPH07106717A - Laminated composite electronic component - Google Patents

Abstract

PURPOSE:To prevent a deterioration in chip-component characteristics, by using an outermost layer on the side of a mounted electronic circuit as a thermal stress relaxation layer having a coefficient of linear expansion smaller than that of the material of a laminated element adjoining to the outermost layer and larger than that of the chip component connected to the electronic circuit. CONSTITUTION:In a laminated composite electronic component, an electronic circuit is provided on a main face of a laminated element 2, in which at least one element out of a coil, a capacitor and a resistor is provided. In addition, at least an outermost layer 4 on the side of a mounted electronic component out of outermost layers on both sides is a thermal-stress relaxation layer having a coefficient of linear expansion smaller than that of the material of the laminated element adjoining to the outermost layer 4 and larger than that of the chip component 7 connected to the electronic circuit. Consequently, the electronic component can withstand a heat cycle test, and reliability in thermal stress can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated composite electronic component in which an electronic circuit is incorporated in a laminated body element to form one functional block.

[0002]

2. Description of the Related Art There has been a demand for miniaturization of electronic circuit devices, and in order to meet the demand, miniaturization of electronic components and development of high-density mounting technology for mounting electronic components in close proximity have been underway. As for miniaturization of electronic parts, so-called compounding has been promoted by reducing the size of individual parts and incorporating a plurality of smaller electronic elements into a single laminated electronic part, and this technology has rapidly progressed with the development of ceramic lamination technology. However, the completed component is mounted on a printed circuit board together with other individual components as a laminated composite electronic component for use.

As a laminated composite electronic component, for example, as shown in FIG. 3, a coil is embedded in a ferrite magnetic body, and a passive element such as a resistor is provided on the main surface of a laminated inductor 21 having external electrodes 20, 20. Conductor circuit is formed, and as an active element such as a transistor or a semiconductor IC, a bare chip 22 of a semiconductor IC is adhered to the conductor land of the circuit by a conductive adhesive 23, that is, so-called die bonding is performed, while the electrode of the bare chip and the conductor are connected. Circuit electrode 2
4 and 24 are connected by gold wires 25, 25 ..., So-called wire bonding is performed, and the entire circuit on this main surface is filled with a resin layer 26 to combine the functions of a plurality of elements to form an electronic circuit. Is widely used as an electronic component. Also, instead of a laminated inductor, a laminated capacitor in which a contenter is embedded in a dielectric ceramic,
Further, it is widely used to use a laminated body element obtained by integrating a laminated inductor and a laminated capacitor in accordance with the above.

As one measure for guaranteeing the reliability of such a laminated composite electronic part, there is an accelerated test method called a heat cycle test. In this method, the component under test is
After being left in a 55 ° C temperature atmosphere for 30 minutes, immediately shifting to a 125 ° C temperature atmosphere and left at that temperature for 30 minutes was defined as one cycle. Repeated 500 cycles, and compared the characteristics before and after the test. It is to check whether or not it is within the standard defined by JIS etc., and if it is within the standard, the reliability is guaranteed.

[0005]

When the above-mentioned heat cycle test is performed on the laminated composite electronic component on which the semiconductor bare chip is mounted, there is a problem that the semiconductor bare chip may be cracked and its characteristics may be deteriorated.

An object of the present invention is to provide a laminated composite electronic component which does not deteriorate the characteristics of the chip component even when a heat cycle test is performed.

[0007]

In order to solve the above-mentioned problems, the present invention provides a laminated composite electronic device having an electronic circuit on the main surface of a laminated device having at least one of a coil, a capacitor and a resistor inside. In the component, at least the outermost layer of the outermost layers forming both main surfaces of the laminate element on the side on which the electronic circuit is mounted is smaller than the linear expansion coefficient of the substrate of the laminate element adjacent to the outermost layer, Provided is a laminated composite electronic component which is a thermal stress relaxation layer having a linear expansion coefficient larger than that of a chip component connected to a circuit. At this time, both outermost layers forming both main surfaces of the laminated element are smaller than the linear expansion coefficient of the base material of the laminated element adjacent to the respective outermost layers, and the wire of the chip component connected to the electronic circuit. The thermal stress relaxation layer has a linear expansion coefficient larger than the expansion coefficient, the linear expansion coefficient of the thermal stress relaxation layer is 2 to 7 × 10 ⁻⁶ / ° C., and the thermal stress relaxation layer and the laminated element are It is preferable to have a diffusion layer in which both components are diffused between the base material and the base material.

In the present invention, the thermal stress relaxation layer has a coefficient of linear expansion smaller than that of the base material of the adjoining laminated body element and larger than that of the chip part connected to the electronic circuit. The base material of the body element has, for example, a coefficient of linear expansion of the ferrite magnetic layer of 10 to 11 × 10 ⁻⁶ /
C, the coefficient of linear expansion of the ceramic dielectric layer is 9 to 10 × 10
^-6 / ° C. On the other hand, the coefficient of linear expansion of chip parts, for example, bare semiconductor chips, is 2 because the silicon substrate is used.
Since it is 3 × 10 ⁻⁶ / ° C., a linear expansion coefficient of 2 to 7 × 10 ⁻⁶ / ° C., which is an intermediate linear expansion coefficient between the linear expansion coefficient of the substrate of the laminated device and the linear expansion coefficient of the bare semiconductor chip, is set. It is preferable to have. The linear expansion coefficient of the thermal stress relaxation layer is 2 × 10 ^-6
If it is lower than / ° C, cracks are likely to occur between the thermal stress relaxation layer and the base material of the laminated body element, and if it is higher than 7 × 10 ^-6 / ° C, cracks are likely to occur in the chip parts. If the ratio of the coefficient of linear expansion between the thermal stress relaxation layer and the chip component mounted on the laminated body element is about 3, cracks are less likely to occur in the chip component, and if it exceeds 5, the rate of cracking increases. The defective rate increases. The defective rate when the bare chip is mounted on the ferrite magnetic layer is higher than the defective rate when the bare chip is mounted on the ceramic dielectric layer. Other chip parts using silicone as a substrate and other chip parts can be considered according to the above. Examples of the material for the thermal stress relaxation layer include alumina powder and other inorganic powders, lead borosilicate glass and other glass powders, mixtures thereof, and other ceramic powders.

[0009]

When the base material of the laminated element and the chip component have different linear expansion coefficients and the rate of expansion and contraction due to heat is greatly different, the stress can be relaxed by the thermal stress relaxation layer having an intermediate linear expansion coefficient. In particular, in the thermal stress relaxation layer having an intermediate linear expansion coefficient, each component diffuses into the base material of the laminated element in contact with the thermal stress relaxation layer, and a diffusion layer having an intermediate linear expansion coefficient between the two is formed. It has the effect of relieving the stress on each of the bases of the laminated body element.

[0010]

EXAMPLES Examples of the present invention will be described below. Example 1 A large number of ferrite magnetic green sheets having a thickness of 80 μm containing Ni—Zn as a main component were formed, through holes were formed in several of them, and the Ag—Pd paste of a conductive paste was screen-printed. Form a coil conductor pattern film forming a part of the coil so as to form a coil as a whole on each, and superimpose them so that the coil conductor pattern film forms a coil, and further use the above ferrite as a cover sheet. A plurality of magnetic green sheets are superposed on both ends thereof to form a laminated inductor unfired body. The coating film of the coil conductor pattern which hits both ends of the coil is pulled out to the end of the ferrite magnetic green sheet, and is later connected to the external electrode. On the other hand, a 100 μm thick insulator green sheet containing Al ₂ O ₃ and lead borosilicate glass as main components is prepared. Next, the above-mentioned insulator green sheets are stacked on both main surfaces of the above-mentioned laminated inductor unfired body, and then pressure-bonded to form a laminated inductor unfired pressure-bonded body. Actually, the multilayer inductor unfired crimped body is not individually manufactured, but a large number of the laminated inductors are formed in one sheet stack, and after the crimping, they are cut into individual laminated inductor unfired crimped bodies.

The individual laminated inductor unfired crimped body is fired at 900 ° C. for 60 minutes to obtain the composite laminated inductor 1 shown in FIG. Regarding this composite laminated inductor 1,
When the linear expansion coefficient was measured by scraping off each part, the laminated inductor body 2 and the diffusion layers 3 and 3 of 50 μm respectively were measured.
It was found that the ceramic insulating layers 4 and 4 each had a thickness of 75 μm. That is, in the laminated inductor body 2, the linear expansion coefficient of the substrate is 11 × 10 ⁻⁶ / ° C., and the linear expansion coefficient of the ceramic insulator layers 4 and 5 is 5 × 10.
^-6 / ° C, and the coefficient of linear expansion of the diffusion layers 3 and 3 is 8 × 10 ^-6
/ ° C. The coefficient of linear expansion of the semiconductor bare chip described later was 2.4 × 10 ⁻⁶ / ° C.

A thick conductor coating film having a conductor land coating film and a thick film resistor coating film are formed on one main surface of the composite laminated inductor 1 by screen printing and baked to form a wiring conductor having conductor lands. A thick film circuit having a resistor is formed. Then, the outer surface of the laminated inductor body 2 from which the coil conductor made of the fired body of the coil conductor coating film is drawn out, the diffusion layers 3 and 3, the ceramic insulator layers 4 and 4.
The external electrode coating film to be connected to the end of the coil conductor is formed on the corresponding outer surface of the by screen printing method and baked,
External electrodes 5, 5 ... Are formed.

The semiconductor bare chip 7 is die-bonded with the conductive epoxy resin adhesive 8 to the conductor lands 6 formed on one main surface of the ceramic insulator layers 4 and 4 of the composite laminated inductor 1 having the external electrodes thus formed. The other electrodes of the semiconductor bare chip 7 and the electrodes 9, 9 of the wiring conductor are wire-bonded with the gold wires 10, 10 ,. Then, the entire electronic circuit including the semiconductor bare chip 7 formed in the main surface is embedded with the resin layer 11. In this way, an electronic circuit is provided on one main surface of the composite laminated inductor 1,
A laminated composite electronic component connected to an inductor in a ferrite magnet is completed.

As such a laminated composite electronic component, DC-
When 50 DC converters were created and their output characteristics were measured, all of them satisfied the standard. In addition, as a result of performing the above-mentioned heat cycle test and continuously repeating 500 cycles and then measuring the output characteristics of the DC-DC converter, none of them was judged to be abnormal beyond the standard.

Example 2 As shown in FIG. 2, a composite laminated inductor 1 was prepared in the same manner as in Example 1, and a different conductor circuit was formed on one of its main surfaces by the same method as in Example 1, and The bumps 14 and 14 of the surface-mounted semiconductor IC chip 13 are connected to the electrodes 12 and 12 by soldering, and a frame 15 that surrounds the entire electronic circuit including this chip is provided on the periphery of the main surface.

Example 3 Insulator green sheet in which the ratio of Al ₂ O ₃ and lead borosilicate glass was changed so that the linear expansion coefficient of the ceramic insulator layer was 5 × 10 ⁻⁶ / ° C. in Example 1. 50 DC-DC converters were prepared in the same manner except that the above was used, and these were also tested in the same manner as in Example 1. As a result, none were judged to be abnormal.

Example 4 A large number of dielectric green sheets containing barium titanate as a main component were prepared, and an internal electrode coating film made of a conductive base was printed on some of the sheets by a screen printing method, and these were coated with respective dielectric layers. The internal electrode coating films are laminated so as to face each other via the green sheet, and a plurality of the above-mentioned dielectric green sheets are laminated as cover sheets on the upper and lower ends of the laminated body to prepare a multilayer capacitor unfired body. The internal electrode coating film on both ends is pulled out to the end portion of the sheet so that it can be connected to external electrodes described later. Then, the unbaked body of the multilayer capacitor and the unbaked body of the multilayer inductor similar to those prepared in Example 1 are stacked, and the green sheets of the insulator used in Example 1 are stacked on both ends of the stacked body and pressure-bonded to form a laminated LC. Create a green compact. Actually, the laminated LC unsintered pressure-bonded bodies are not individually prepared, but a large number of them are formed in a sheet stack of one unit.
Cut into unfired crimps. This laminated LC unfired pressure-bonded body was fired to prepare a composite laminated LC body including a laminated inductor and a laminated capacitor. In the same manner as in Example 1, this composite laminated LC body was provided with coil conductors at both ends of the laminated inductor,
External electrodes connected to the internal electrodes on both ends of the multilayer capacitor were formed, and a conductor circuit was formed on one main surface of the external electrode to connect a semiconductor bare chip to produce a multilayer composite electronic component. When 50 Dolby noise reductions were prepared as such laminated composite electronic parts and the response characteristics were measured, none were judged to be abnormal.

Reference Example 1 Insulator green sheet in which the ratio of Al ₂ O ₃ and lead borosilicate glass was changed so that the linear expansion coefficient of the ceramic insulator layer was 8 × 10 ⁻⁶ / ° C. in Example 1. 50 DC-DC converters were prepared in the same manner except that No. 1 was used, and these were also tested in the same manner as in Example 1. As a result, 5 were judged to be abnormal.

Reference Example 2 Insulator green sheet in which the ratio of Al ₂ O ₃ and lead borosilicate glass was changed so that the linear expansion coefficient of the ceramic insulator layer was 9 × 10 ⁻⁶ / ° C. in Example 1. 50 DC-DC converters were prepared in the same manner except that No. was used, and these were also tested in the same manner as in Example 1. As a result, 10 were judged to be abnormal.

Reference Example 3 Insulation in which the ratio of Al ₂ O ₃ , lead borosilicate glass, and quartz glass was changed so that the linear expansion coefficient of the ceramic insulator layer was 1 × 10 ⁻⁶ / ° C. in Example 1. 50 DC-DC converters were prepared in the same manner except that the body green sheet was used, and these were also tested in the same manner as in Example 1. As a result, 5 were judged to be abnormal.

[0021]

According to the present invention, the thermal stress has a linear expansion coefficient smaller than that of the base material of the laminated body element and larger than that of the chip part connected to the electronic circuit provided in the laminated body element. Since the relaxation layer is provided between the laminated element and the chip component, it is possible to provide a laminated composite electronic component that can withstand the above-mentioned heat cycle test. For example, the semiconductor bare chip is not cracked, and thermal stress (heat Reliability against shock) can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a laminated composite electronic component according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a laminated composite electronic component according to a second embodiment.

FIG. 3 is a vertical sectional view of a conventional laminated composite electronic component.

[Explanation of symbols]

 1 Composite Multilayer Inductor 2, 2 Multilayer Inductor Main Body 3, 3 Diffusion Layer 4, 4 Ceramic Insulator Layer 7 Bare Chip 13 Surface Mount Semiconductor IC Chip

Claims (4)

[Claims] 1. A laminated composite electronic component having an electronic circuit on the main surface of a laminated body element having at least one element of a coil, a capacitor and a resistor therein, and outermost layers constituting both principal surfaces of the laminated body element. At least the outermost layer on the side on which the electronic circuit is mounted is smaller than the linear expansion coefficient of the base material of the laminate element adjacent to the outermost layer, and is larger than the linear expansion coefficient of the chip component connected to the electronic circuit. A laminated composite electronic component, which is a thermal stress relaxation layer having: 2. A chip part connected to the electronic circuit, wherein both outermost layers forming both main surfaces of the laminated element are smaller than a linear expansion coefficient of a base material of the laminated element adjacent to the respective outermost layers. The laminated composite electronic component according to claim 1, which is a thermal stress relaxation layer having a linear expansion coefficient larger than the linear expansion coefficient of. 3. The coefficient of linear expansion of the thermal stress relaxation layer is 2 to 7 × 1.
The laminated composite electronic component according to claim 1 or 2, which has a temperature of 0 ^-6 / ° C. 4. A diffusion layer in which the respective components of both are diffused between the thermal stress relaxation layer and the substrate of the laminated body element.
Alternatively, the laminated composite electronic component described in 3 above.