JP4432517B2 - Composite multilayer board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, although a conventional composite multilayer substrate is so constituted out of a ceramic substrate and a composite resin material layer formed on the rear surface of the ceramic substrate as to join the ceramic substrate to a printed wiring board via the composite resin material layer, since the respective physical properties (e.g., thermal expansion coefficients) and the respective surface states of the ceramic substrate and the printed wiring board are different from each other largely, it has been difficult to deal with both by a single composite resin material layer, and therefore, there has been the possibility that, when matching the thermal expansion coefficient of the composite resin material layer with the one of either one of the ceramic substrate and the printed wiring board, the interlayer exfoliation and the crack which are caused by thermal impacts occur in the interface on both the sides of which the difference between thermal expansion coefficients is large. <P>SOLUTION: A composite multilayer substrate 1 is the one which so has a ceramic multilayer substrate 2 and so has a resin laminate 3 obtained by laminating first, second, and third resin layers 3A, 3B, 3C as to join the rear surface of the ceramic multilayer substrate 2 to the top surface of the resin laminate 3. Hereupon, the first, second, and third resin layers 3A, 3B, 3C have respectively different thermal expansion coefficients from each other. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a composite multilayer substrate, and more particularly to a highly reliable composite multilayer substrate.

  As a conventional composite multilayer substrate, for example, a composite multilayer substrate used in a high-frequency semiconductor device described in Patent Document 1 is known. In this high-frequency semiconductor device, a composite resin material layer made of an epoxy resin and an inorganic filler formed on the lower surface of a ceramic substrate is formed, and the lower portion of the composite resin material layer has a flat shape and is used for an external connection terminal Electrodes are formed inside the composite resin material layer, embedded with semiconductor elements and passive components connected to a ceramic substrate, and as a module package with an all-in-one structure for transmission and reception, miniaturization and high-density mounting Realized. Further, high heat dissipation is realized by embedding a conductive resin in the via hole of the composite resin material layer.

  The composite multilayer substrate used for the high-frequency semiconductor device includes a ceramic substrate and a composite resin material layer formed on the lower surface of the ceramic substrate. The composite resin material layer is formed of a resin and an inorganic filler. The heat dissipation from the composite resin material layer is enhanced by adding an inorganic filler to the composite resin material layer.

JP 2003-124435 A

  However, in the case of the composite multilayer substrate used in the high-frequency semiconductor device described in Patent Document 1, the ceramic substrate includes a ceramic substrate and a composite resin material layer formed on the lower surface, and the ceramic substrate is interposed via the composite resin material layer. However, since the physical properties and surface states of the ceramic substrate and the printed wiring board are greatly different from each other, it is difficult to deal with both with a single composite resin material layer. For example, in general, the thermal expansion coefficient of ceramic is in the range of 5.0 to 9.0 ppm / ° C., and the thermal expansion coefficient of the printed wiring board 20 is in the range of 12.0 to 18.0 ppm / ° C. Therefore, as described in Patent Document 1, when an inorganic filler is added to the resin material and the thermal expansion coefficient of the composite resin material layer is matched to either the ceramic substrate or the printed wiring board, the difference in thermal expansion coefficient is There is a risk of delamination or cracks due to, for example, thermal shock at a large interface.

  The present invention has been made to solve the above-described problems. Thermal shock during mounting on a printed wiring board, delamination between a ceramic substrate and a resin layer, and peeling from a printed wiring board even in a high temperature environment before and after mounting. An object of the present invention is to provide a highly reliable composite multilayer substrate that can be surely prevented and that is excellent in impact resistance and moisture resistance.

  As a result of various studies on the composite multilayer substrate, the present inventors have found the following. That is, in many cases, the composite multilayer substrate including the ceramic substrate and the resin layer is mounted on the printed wiring board after a long time, but in order to strengthen the connection between the printed wiring board and the resin layer. It is more preferable to strongly bond the resin itself to the printed wiring board than to solder-connect the external terminals of the resin layer. For that purpose, it is better to mount the resin layer on the printed wiring board in a semi-cured state, and then to perform the main curing (to complete the curing). However, when the resin layer is in a semi-cured state, the bonding force with the ceramic substrate is weak, and there is a problem that the resin layer easily peels from the ceramic substrate.

  In addition, since the resin layer plays a role of protecting the built-in mounting components, it needs to be dense and hard, while the resin layer also has a role of mitigating the drop impact, so it can be used for external forces such as a drop impact. On the other hand, the elasticity which deform | transforms flexibly is calculated | required, However, These two requirements are contradictory and it cannot be satisfied simultaneously with one type of resin.

  Therefore, by adopting a specific structure as the resin layer of the composite multilayer substrate, it can be reliably bonded to both the ceramic substrate and the printed wiring board, and the composite multilayer substrate may be delaminated between the ceramic substrate and the resin layer. In addition, it was found that the mounted components can be reliably protected even when the mounted components are incorporated.

The present invention has been made on the basis of the above knowledge, and the composite multilayer substrate according to claim 1 includes a ceramic substrate having a first main surface and a second main surface opposite to the first main surface, and a first main surface. A resin laminate having a surface and a second main surface facing the surface, wherein the second main surface of the ceramic substrate and the first main surface of the resin laminate are joined, and A composite multilayer substrate in which a circuit pattern formed on a ceramic substrate and an external terminal electrode formed on a second main surface of the resin laminate are electrically connected, each resin constituting the resin laminate Each of the layers has a different degree of curing, and the degree of cure on the second main surface side of the resin laminate is lower than the degree of cure on the first main surface side .

The composite multilayer substrate according to claim 2 of the present invention is characterized in that, in the invention according to claim 1, the resin layer on the second main surface side of the resin laminate is in a semi-cured state. To do.

The composite multilayer substrate according to claim 3 of the present invention is characterized in that, in the invention according to claim 1 or 2, each of the resin layers contains a resin material and an inorganic powder, respectively. is there.

The composite multilayer substrate according to claim 4 of the present invention is the ceramic multilayer substrate according to any one of claims 1 to 3 , wherein the ceramic substrate is a ceramic multilayer substrate in which a plurality of ceramic layers are laminated. Thus, the ceramic multilayer substrate has a circuit pattern mainly composed of Ag or Cu.

The composite multilayer substrate according to claim 5 of the present invention is the composite multilayer substrate according to any one of claims 1 to 4 , wherein the external terminal electrode is formed of a metal foil. It is characterized by.

According to a sixth aspect of the present invention, there is provided the composite multilayer substrate according to any one of the first to fifth aspects, wherein the resin laminate includes a chip component. Is.

Thus, the composite multilayer substrate of the present invention includes the ceramic substrate and the resin laminate bonded to the ceramic substrate as described above. The ceramic substrate has a first main surface (upper surface) and a second main surface (lower surface) opposite to the first main surface. Similar to the ceramic substrate, the resin laminate has a first main surface (upper surface) and a second main surface (lower surface). Therefore, the composite multilayer substrate is formed by bonding the lower surface of the ceramic substrate and the upper surface of the resin laminate.

  The ceramic substrate may be a ceramic substrate formed by firing a single ceramic green sheet or a ceramic multilayer substrate formed by firing a laminate of a plurality of ceramic green sheets. A circuit pattern for mounting active chip components such as semiconductor elements or passive chip components such as capacitors and inductors is formed on the upper surface of the ceramic substrate, and a circuit pattern for mounting these chip components is also formed on the lower surface of the ceramic substrate. May be. The chip component mounted on the lower surface of the ceramic substrate is embedded in the resin laminate, and the resin laminate side is bonded to the printed wiring board. The upper and lower circuit patterns are electrically connected by via hole conductors filled in via holes formed in the ceramic substrate. The chip component mounted on the upper surface of the ceramic substrate may be embedded in the resin layer or covered with a case.

  When the ceramic substrate is formed as a ceramic multilayer substrate and a circuit pattern is formed therein, the circuit pattern is formed with a conductive paste on a predetermined ceramic green sheet and the via paste is filled into the via hole. A circuit pattern can be formed in the ceramic substrate by firing a laminate formed by laminating a predetermined number of sheets. The circuit pattern and the via hole conductor preferably contain, for example, Ag or Cu as a main component, and the circuit pattern and the via hole conductor may be the same metal component or different.

Therefore, the ceramic substrate is preferably formed of a low-temperature sintered ceramic material that can be co-fired with a conductive paste containing Ag and Cu, which are low melting point metals, as main components at a low temperature of 1000 ° C. or lower. The low-temperature sintered ceramic material refers to a material that can be co-fired with the low melting point metal, and in particular, can be fired at a temperature of 1000 ° C. or lower. Examples of the low-temperature sintered ceramic material include ceramic powders such as alumina, forsterite and cordierite, glass composite materials obtained by mixing borosilicate glass powders with these ceramic powders, ZnO-MgO-Al ₂ O ₃ -SiO crystallized glass-based material using ₂ based crystallized glass, use a _BaO-Al 2 O 3 -SiO ₂ ceramic powder and _{Al 2 O 3 -CaO-SiO 2} -MgO-B 2 O 3 based ceramic powder, etc. Non-glass-based materials that have been used.

  The resin laminate is formed by laminating a plurality of resin layers, and each resin layer has different characteristics. Here, the characteristics of the resin layer refer to physical properties and properties such as a thermal expansion coefficient, an elastic modulus, and a degree of curing of the resin. Each resin layer may include a resin material and an inorganic powder. The resin material is not particularly limited. For example, a thermosetting resin or a photocurable resin can be used, and an epoxy resin-based thermosetting resin is particularly preferable. The inorganic powder is not particularly limited. However, since the metal powder is conductive and may impair the insulating properties of the resin layer, an insulating powder such as a ceramic powder is preferable. The resin material and the inorganic powder may be the same or different from each other as required. In addition, the inorganic powder may be used with the same particle size in each resin layer, or may have different particle sizes as necessary.

  The characteristics of the resin layer differ depending on the blending ratio of the resin material and the inorganic powder, the degree of polymerization (curing degree) of the resin material, and the like. As the content of the inorganic powder in the resin layer increases, the physical property value of the inorganic powder approaches, and as the content of the inorganic powder decreases, the properties of the resin layer approach the physical property value of the resin material. The ceramic powder preferable as the inorganic powder generally has a smaller thermal expansion coefficient than that of the resin. Therefore, as the content of the ceramic powder in the resin layer increases, the expansion coefficient of the resin layer decreases and approaches that of the ceramic substrate. The smaller the is, the closer the thermal expansion coefficient is to that of the printed wiring board. In addition, as the content of the ceramic powder in the resin layer increases, it becomes harder and the elastic modulus decreases, and as the content decreases, the softening increases and the elastic modulus increases. As described above, the thermal expansion coefficient of the ceramic substrate is generally 5.0 to 9.0 ppm / ° C., and the thermal expansion coefficient of the printed wiring board is 12.0 to 18.0 ppm / ° C.

  Each of the resin layers may have a different thermal expansion coefficient. And as a resin laminated body, the thing by which the resin layer with a small thermal expansion coefficient is arrange | positioned at the ceramic substrate side, ie, the upper surface side, and the resin layer with a large thermal expansion coefficient is arrange | positioned at the printed wiring board side is preferable. By disposing a resin layer having a small coefficient of thermal expansion on the ceramic substrate side of the resin laminate, that is, on the lower surface side, the difference in coefficient of thermal expansion between the resin laminate and the ceramic substrate is reduced to prevent delamination, or Can be suppressed. By placing a resin layer with a large coefficient of thermal expansion on the printed wiring board side of the resin laminate, thermal shock when soldering the composite multilayer board to the printed wiring board or using the composite multilayer board as a mounted product Interfacial peeling between the resin laminate and the printed wiring board can be prevented or suppressed even under a high temperature environment.

  The thermal expansion coefficient of the resin layer including the upper surface of the resin laminate, that is, the resin layer bonded to the ceramic substrate, is preferably within ± 2 ppm / ° C. of the thermal expansion coefficient of the ceramic substrate. Usually, if the difference in thermal expansion coefficient between layers in the multilayer wiring board is within ± 2 ppm / ° C., there is substantially no possibility of delamination or cracks. If the thermal expansion coefficient of the ceramic substrate is, for example, 10 ppm / ° C., the thermal expansion coefficient of the resin layer in contact with the ceramic substrate is preferably 10 ± 2 ppm / ° C. Such a thermal expansion coefficient can be adjusted to the said range by adjusting content of the inorganic powder in a resin layer, for example, ceramic powder.

  The thermal expansion coefficient of each resin layer is preferably gradually increased from the uppermost layer to the lowermost layer of the resin laminate. If there is a large difference in the content of inorganic powder between the resin laminate and the ceramic substrate, between the resin laminate and the printed wiring board, or between the resin layers in the resin laminate, There is a possibility that the difference in thermal expansion coefficient between layers becomes large and delamination occurs. Therefore, delamination between the resin layers is prevented by gradually increasing the thermal expansion coefficient from the uppermost resin layer to the lowermost resin layer to give an inclination to the thermal expansion coefficient inside the resin laminate. That is, it is preferable that the content of the inorganic powder in the uppermost resin layer is the highest, the content of the inorganic powder is decreased in the lower layer, and the content of the inorganic powder in the lowermost resin layer is minimized.

  Each of the resin layers preferably has a different elastic modulus, and the elastic modulus on the lower surface side of the resin laminate is preferably higher than the elastic modulus on the upper surface side. By increasing the elastic modulus of the lower surface of the resin laminate, the impact when the composite multilayer substrate is dropped is absorbed so that the impact force is not transmitted to the inside as much as possible. Therefore, even if the chip component is built in the resin laminate, the impact on the chip component is light. In order to increase the elastic modulus of the resin layer, the content of the inorganic powder in the resin layer may be decreased.

  It is preferable that each said resin layer has a different hardening degree, respectively, and the lower hardening degree of the resin laminated body is lower than the upper hardening degree. That is, it is preferable that the resin layer on the ceramic substrate side is hard and the resin layer on the printed wiring board side is soft. High degree of cure of the resin layer means that the crosslinking reaction of the thermosetting resin constituting the resin layer has progressed and hardened, for example, and low degree of cure of the resin layer means, for example, the thermosetting that constitutes the resin layer This is a soft state in which the crosslinking reaction of the functional resin does not proceed. By lowering the degree of cure of the resin layer on the printed wiring board side, the adhesion between the resin layer and the printed wiring board can be increased, and both can be firmly connected. When the thermosetting resin is used, the degree of cure of the resin layer can be appropriately adjusted depending on the amount of heat input.

  The lowermost resin layer of the resin laminate is preferably in a semi-cured state (so-called B-stage state). When this resin layer is in the B stage, it provides adhesion to the printed wiring board and increases adhesion, and is firmly bonded to the printed wiring board, and the resin layer is completely cured by heat treatment after bonding. Thus, it can be firmly bonded to the printed wiring board.

  Moreover, it is preferable that the external terminal electrode on the lower surface of the resin layer is formed of a metal foil. The metal foil can be easily formed on the resin layer, and has a low resistance and is inexpensive. The external terminal electrode can be joined to the electrode of the printed wiring board by soldering or the like as the external terminal electrode when mounted on the printed wiring board.

  Moreover, it is preferable that the electrode which occupies 3 to 80% of the bottom area of this ceramic substrate is formed in the interface of the said ceramic substrate and resin laminated body. This electrode may be formed as a circuit pattern on the ceramic substrate, may be formed as a dummy electrode independent of the circuit pattern, or may include both.

The electrode formed on the lower surface of the ceramic substrate is preferably formed by firing a conductive paste formed in a predetermined pattern together with the ceramic substrate. By firing the conductive paste, to express an anchoring effect to a binder or the like disappears to the electrode interior and surface are pores formed surface roughness R _max of the electrodes becomes larger than the surface roughness R _max of the ceramic substrate The bonding strength between the resin layer and the resin layer can be dramatically increased, and the delamination between the ceramic substrate and the resin layer can be reliably prevented. For example, the surface roughness R _max of the ceramic substrate is about several μm, but the surface roughness R _max of the sintered metal is about several tens μm, which is an order of magnitude higher than that of the ceramic substrate, and the anchor effect is expected. can do.

  The electrode can be used as a ground electrode. By using this electrode as a ground electrode, the distance between the ground electrode and the ground electrode of the printed wiring board is shortened and the parasitic inductance value is reduced. For example, when a composite multilayer board is used as a high-frequency component, the high-frequency characteristics are improved. be able to.

  Further, the resin laminate can incorporate chip parts such as active chip parts such as semiconductor elements and passive chip parts such as capacitors, inductors, and resistors. The resin laminate seals and protects the built-in chip components from the outside. The chip component is usually connected to a predetermined part of the circuit pattern of the ceramic substrate. Therefore, since the chip component is sealed with a hard and dense resin layer having a high degree of curing on the ceramic substrate side, moisture can be prevented from entering from the outside and reliably protected. Further, even when the composite multilayer substrate falls, the impact force at the time of dropping can be absorbed by the soft resin layer at the lowermost layer, the drop impact on the chip component can be reduced, and peeling from the ceramic substrate can be prevented.

According to the present invention, a ceramic substrate having first and second main surfaces facing each other, and a resin laminate having first and second main surfaces facing each other, the second main surface of the ceramic substrate is provided. The resin layer is joined to the first main surface of the resin laminate, each resin layer constituting the resin laminate has a different degree of cure, and the degree of cure on the second main surface side of the resin laminate is Since the composite multilayer substrate is configured with a lower degree of curing than the first main surface side, the bonding force between the resin laminate and the ceramic substrate is increased, and the adhesion force with the printed wiring board on which the composite multilayer substrate is mounted is increased. It can reliably prevent delamination between the ceramic substrate and the resin layer and delamination from the printed wiring board even under high temperature environment before and after mounting on the printed wiring board, and impact resistance Excellent reliability and moisture resistance It is possible to provide a highly complex multi-layer substrate.

  Hereinafter, the present invention will be described based on the embodiment shown in FIG. FIG. 1 is a sectional view showing an embodiment of the composite multilayer substrate of the present invention. 2 (a) to 2 (g) are process diagrams showing a process for producing the first resin layer of the composite multilayer substrate shown in FIG. 1, and FIGS. 3 (a) and 3 (b) are respectively shown in FIG. FIG. 4 is a cross-sectional view showing another embodiment of the composite multilayer substrate of the present invention, and FIG. 4 is a process diagram showing the step of joining the ceramic multilayer substrate and the resin laminate of the composite multilayer substrate.

  For example, as shown in FIG. 1, the composite multilayer substrate 1 of the present embodiment has a ceramic multilayer substrate 2 composed of a plurality of ceramic layers 2 </ b> A stacked one above the other and a lower surface (second main surface) of the ceramic multilayer substrate 2. It has the laminated resin laminate 3 and is mounted on the printed wiring board 20 and used. Each ceramic layer 2A is formed by co-firing a low-temperature sintered ceramic material with the circuit pattern 4 at a low temperature of 1000 ° C. or lower. The circuit pattern 4 includes conductive patterns 4A such as in-plane wirings and electrodes formed on each ceramic layer 2, and via-hole conductors 4B that electrically connect the upper and lower conductive patterns 4A. For example, Ag or Cu is a main component. It is formed as a metal sintered body. A plurality of chip components 5 are mounted on the conductor pattern 4 </ b> A on the upper surface (first main surface) of the ceramic multilayer substrate 2. The chip component 5 includes, for example, an active chip component 5A such as a semiconductor element and a passive chip component 5B such as a capacitor, an inductor, and a resistor.

  Further, as shown in FIG. 1, the resin laminate 3 is formed by laminating, for example, first, second, and third resin layers 3A, 3B, and 3C, and the first resin layer 3A is a ceramic multilayer substrate. The third resin layer 3C is adhered to the printed wiring board 20 when the composite multilayer substrate 1 is mounted. An active chip component 5A and a passive chip component 5B are embedded as chip components 5 in the first and second resin layers 3A and 3B, respectively, and ceramics are formed via circuit patterns 6 formed in the resin layers 3A and 3B. It is electrically connected to the multilayer substrate 2. The circuit pattern 6 includes a conductor pattern 6A formed in each resin layer, a via-hole conductor 6B that electrically connects the upper and lower conductor patterns 6A, and an external terminal electrode 6C. The conductor pattern 6A is formed of a metal foil such as a copper foil, and the via-hole conductor 6B is formed of a conductive resin containing metal particles, solder, or the like.

  Each of the first, second, and third resin layers 3A, 3B, and 3C is formed of a mixture of a resin material (for example, an epoxy thermosetting resin) and an inorganic powder (for example, ceramic powder). The first, second, and third resin layers 3A, 3B, and 3C have different ceramic powder contents and different properties such as physical properties and properties.

  In the present embodiment, the first resin layer 3A has the highest ceramic powder content, has the smallest thermal expansion coefficient close to the thermal expansion coefficient of the ceramic multilayer substrate 2, and the third resin layer 3C is made of ceramic powder. It has the smallest content and the largest thermal expansion coefficient close to the thermal expansion coefficient of the printed wiring board 20. The thermal expansion coefficient of the first resin layer 3A is adjusted to a magnitude of ± 2 ppm / ° C. with respect to the thermal expansion coefficient of the ceramic multilayer substrate 2, for example.

  Therefore, even when the composite multilayer substrate 1 receives a thermal shock during mounting or is in a high temperature environment, the difference in thermal expansion coefficient between the ceramic multilayer substrate 2 and the first resin layer 3A is small, resulting in delamination. There is no fear, and the difference in thermal expansion coefficient between the third resin layer 3C and the printed wiring board 20 is also small, so there is no possibility of peeling from the printed wiring board 20.

  In addition, the first, second, and third resin layers 3A, 3B, and 3C have a lower degree of curing in this order, and the first, second, and third resin layers 3A, 3B, and 3C are Since the content of the ceramic powder is reduced in this order, the first resin layer 3A has the lowest elastic modulus, the hardest and most densely formed, and the third resin layer 3C has the lowest elastic modulus, It is the softest formed. Further, in the composite multilayer substrate 1 before mounting, the third resin layer 3 </ b> C is in a semi-cured state, and the third resin layer 3 </ b> C is cured and bonded to the printed wiring substrate 20 when mounted on the printed wiring substrate 20. Therefore, the composite multilayer substrate 1 is firmly bonded to the printed wiring board 20 via the third resin layer 3C. In addition, when the third resin layer 3C is cured, the first and second resin layers 3A and 3B are further cured to form a dense and hard structure combined with a high content of the ceramic powder.

  Accordingly, since the first and second resin layers 3A and 3B have a hard structure, each chip component 5 is sealed to prevent moisture from entering from the outside and reliably protect the chip component 5. Moreover, since the composite multilayer substrate 1 is not deformed even if it is dropped in a state where it is mounted on the printed wiring board 20, there is no possibility that the chip component 5 is detached from the circuit pattern 5. Further, since the third resin layer 3C has the most elasticity and is soft, even if the composite multilayer substrate 1 is dropped while mounted on the printed wiring board 20, the impact force when the third resin layer 3C is dropped on the third resin layer 3C. And the impact force is not transmitted to the chip component 5, so that the chip component 5 can be more reliably protected.

  Next, a method for manufacturing the composite multilayer substrate of Example 1 will be specifically described with reference to FIGS.

(1) Production of Ceramic Green Sheet In this example, 55 parts by weight of alumina particles having a center particle diameter of 1.0 μm and 45 parts by weight of borosilicate glass having a center particle diameter of 1.0 μm and a softening point of 600 ° C. After mixing, an organic solvent, a dispersant, an organic binder, and a plasticizer are added to the mixture to prepare a slurry, which is then applied onto a carrier film made of a polyethylene terephthalate resin, and ceramic green for low-temperature sintering. A sheet was produced.

  Thereafter, a conductive paste containing Ag powder or Cu powder is used as a carrier film in a state in which a ceramic green sheet having via hole conductor holes formed at predetermined locations by laser processing or punching is in close contact with a smooth support base. A squeegee was used to push into the via hole conductor hole in the ceramic green sheet, and at the same time, the excess conductive paste was scraped off to form a via paste layer for the via hole conductor. At this time, the conductive paste can be surely filled into the via hole by attaching a suction mechanism to the support base and making the via hole have a negative pressure. Then, conductive paste was screen-printed on each ceramic green sheet to form a conductor paste layer serving as a conductor pattern such as in-plane wiring and electrodes.

(2) Production of Raw Ceramic Laminate First, the ceramic green sheet forming the uppermost ceramic layer is mounted on a fixing jig with the carrier film removed. Next, the ceramic green sheet to be laminated is laminated on the previously placed ceramic green sheet with the carrier film removed. At this time, the ceramic green sheets may be pressure-bonded by applying a predetermined pressure. Thereafter, the ceramic green sheets were sequentially laminated in a predetermined order, and finally the lowermost ceramic green sheets were laminated to obtain a raw laminate.

(3) Production of Ceramic Multilayer Substrate After removing the binder from the raw laminate, the laminate was fired at 950 ° C. for 1 hour to obtain a ceramic multilayer substrate 2 shown in FIGS. The ceramic sintered body that is the base material of the ceramic multilayer substrate 2 was composed of an α-alumina crystal phase that is a main phase, an amorphous phase, and a trace crystal phase that appears to be an anorthite phase and a wollastonite phase. As a result of measurement using a thermomechanical analyzer (TMA), the thermal expansion coefficient of the ceramic at 20 to 300 ° C. was 7.7 ppm / ° C.

(4) Production of resin sheet for resin laminate The following first, second, and third materials are each formed into a sheet shape on a carrier film by a doctor blade method, and the first, second, and third materials are formed. First, second, and third resin sheets for forming the resin layers 3A, 3B, and 3C were obtained. Under the present circumstances, the crosslinking reaction of epoxy-type thermosetting resin was advanced by heat-processing these, and it adjusted to the viscosity of the grade which epoxy-type thermosetting resin does not flow out on a carrier film. The optimum heat treatment time varies depending on the composition of the epoxy thermosetting resin.
First material: A mixture of 73 parts by weight of a pulverized material (average particle size 2.0 μm) obtained by pulverizing the same ceramic sintered body as the ceramic multilayer substrate with 27 parts by weight of an epoxy thermosetting resin. The thermal expansion coefficient after curing at ˜300 ° C. was 9.6 ppm / ° C.
Second material: 45 parts by weight of the epoxy thermosetting resin mixed with 55 parts by weight of a pulverized ceramic sintered body (average particle size: 2.0 μm) and cured at 20 to 300 ° C. The later thermal expansion coefficient was 11.5 ppm / ° C.
Third material: 55 parts by weight of the epoxy thermosetting resin mixed with 45 parts by weight of a pulverized ceramic sintered body (average particle size: 2.0 μm), cured at 20 to 300 ° C. The thermal expansion coefficient of the later third resin layer was 12.4 ppm / ° C.
However, the epoxy thermosetting resin used for the third resin layer requires a longer time for thermosetting than the epoxy thermosetting resin in the first and second resin layers, and the elastic modulus after curing. Is also low.

(5) Production of Resin Laminate First, in the step shown in FIG. 2, a first resin sheet 13 </ b> A that incorporates the chip component 5 to be a first resin layer is produced. That is, as shown in FIG. 2A, a metal foil (for example, copper foil) 16A having a thickness of about 10 to 40 μm is pasted on the support 10, and a photoresist is applied to the surface of the copper foil 16A, and a photomask After irradiating with light, the photoresist is developed to remove unnecessary portions to expose the copper foil 16A. Next, the exposed portion of the copper foil 16A was removed by etching, and then the photoresist film was removed to form a conductor pattern 6A having a predetermined shape shown in FIG. Next, as shown in FIG. 2 (c), the chip component 5 (active chip component 5A, passive chip component 5B) is fixed on the conductive pattern 6A by solder or conductive adhesive, and then in FIG. 2 (d). As shown, the first resin sheet 13A was thermocompression bonded. At this time, residual air in the periphery of the chip component 5 between the metal foil and the resin can be effectively reduced by performing thermocompression bonding of the first resin sheet 13A in a reduced pressure atmosphere. Next, as shown in FIG. 2E, a via hole 16B was formed in the first resin sheet 13A by injecting a light beam L such as a laser beam from the first resin sheet 13A having no copper foil. In general, since light rays are easily absorbed by the resin and reflected by the metal, the via hole 16B penetrating only the first resin sheet 13A can be formed without making a hole in the conductor pattern 6A. These via holes 16B are filled with solder or conductive resin (a mixture of metal particles such as Au, Ag, Cu, Ni and thermosetting resin) as shown in FIG. 2 (f) to form via hole conductors 6B. After that, as shown in FIG. 2G, the support 10 was peeled off to obtain a first resin sheet 13 </ b> A containing the chip component 5. Thereafter, a second resin sheet 13B (see FIG. 3A) in which the chip component 5 is incorporated is manufactured in the same procedure as the first resin sheet 13A, and further, a third resin sheet in which the chip component is not incorporated. 13C (see FIG. 3A) was produced. The conductor pattern of the third resin sheet 13C is formed as the external terminal electrode 6C.

(6) Production of Composite Multilayer Substrate As shown in FIG. 3A, the ceramic multilayer substrate 2 is fixed with the joint surface facing upward, and the first, second, and third resin sheets 13A, The composite multilayer substrate 1 shown in FIG. 3B was manufactured by combining the resin multilayer body 3 in which the chip component 5 and the circuit pattern 6 were built and the ceramic multilayer substrate 2 bonded together in the order of 13B and 13C. The composite multilayer substrate 1 has a layer structure in which the ceramic multilayer substrate 2, the first resin layer 3A, the second resin layer 3B, and the third resin layer 3C are laminated in this order from the lower side. It consists of 1st, 2nd, 3rd resin layer 3A, 3B, 3C. The combined composite multilayer substrate 1 was heat-treated at 170 ° C. for 1 hour. By this heat treatment, the first and second resin layers 3A and 3B are fully cured, but the third resin layer 3C has a large amount of epoxy thermosetting resin and is slow to cure so that it is in a semi-cured state. stay. The composite multilayer substrate 1 in which the chip component 5 was built in the resin laminate 3 was obtained by the above procedure. The first, second, and third resin sheets 13A, 13B, and 13C may be integrated in advance and then joined to the ceramic multilayer substrate 2.

  The composite multilayer substrate 1 of this embodiment is mounted on the printed wiring board 20 as a module component. The thermal expansion coefficient of the printed wiring board 20 is 12 to 18 ppm / ° C. Moreover, the thermal expansion coefficient of a general ceramic sintered body is 10 ppm / ° C. or less. When materials with different coefficients of thermal expansion are joined, especially when the joint surface is wide, delamination and cracks may occur due to the stress acting on the interface. If the difference in expansion coefficient is 2 ppm / ° C. or less, delamination and cracks do not substantially occur.

  As described above, according to the present embodiment, the resin laminate 3 constituting the composite multilayer substrate 1 is composed of a plurality of different first, second, and third resin layers 3A, 3B, and 3C, and the resin laminate 3 The thermal expansion coefficient of each of the resin layers 3A, 3B, and 3C is inclined to reduce the difference in thermal expansion coefficient between the ceramic multilayer substrate and the resin laminate, and between the resin laminate and the printed wiring board 20. Therefore, the reliability of the composite multilayer board mounted on the printed wiring board 20 with respect to thermal shock can be remarkably improved, and particularly the reliability in the composite multilayer board 1 having a large area can be remarkably improved.

  In addition, according to the present embodiment, the first resin layer 3A bonded to the ceramic multilayer substrate is fully cured, and the third resin layer 3C on the printed wiring board 20 side is in a semi-cured state. The third multilayer resin layer 3C is fully cured after being mounted on the printed wiring board 20, whereby the composite multilayer board 1 and the printed wiring board 20 are bonded via the third resin layer 3C to be firmly bonded. Can do.

  In addition, according to the present embodiment, since the elastic modulus of the third resin layer 3C is higher than that of the first and second resin layers 3A and 3B of the resin laminate 3 in which the chip component 5 is embedded, the composite multilayer substrate. When the printed wiring board 20 mounted with 1 is subjected to a drop impact, the third resin layer 3C can absorb the drop impact and mitigate the drop impact to the ceramic multilayer substrate 2. Further, since the first and second resin layers 3A and 3B are dense and hard, it is possible to prevent the chip component 5 from being deteriorated due to the intrusion of moisture and to prevent the chip component 5 from being deformed by an impact. The connection state with the conductor pattern 6A can be maintained. That is, the resin laminate 3 is composed of resin layers having different physical properties, and the function of the resin layer is divided into a portion that protects the chip component 5 and a portion that absorbs impact, so that the chip component 5 is protected and dropped. And a highly reliable composite multilayer substrate 1 can be obtained.

  In the present embodiment, the same material is used for the first, second and third resin layers. Then, after the first and second resin sheets are pressure-bonded to the ceramic multilayer substrate, the first and second resin sheets are thermally cured by heat treatment for a certain time. Subsequently, after heat-bonding the third resin sheet, heat treatment is performed. By the second heat treatment, the first and second resin layers are fully cured, and the third resin layer is in a semi-cured state. Thus, even if the 1st, 2nd, 3rd resin layer is formed with the same material, the 1st, 2nd resin layer and the 3rd resin layer differ in the degree of hardening, and the 3rd resin Since the layer is in a semi-cured state, it can be firmly bonded to the printed circuit board, and the third resin layer has a higher elastic modulus than the first and second resin layers. It can be absorbed and the built-in chip components can be protected. And since a resin laminated body can be formed with a single material, a manufacturing process can be simplified.

  As shown in FIG. 4, the composite multilayer substrate 1 of the present embodiment does not incorporate chip components in the resin laminate 3, and an electrode 4 </ b> C is formed at the interface between the ceramic multilayer substrate 2 and the resin laminate 3. Other than that, the configuration is the same as in the first embodiment. The electrode 4C is formed as a part of the circuit pattern 4 together with the circuit pattern 4 when the ceramic multilayer substrate 2 is manufactured. The electrode 4 </ b> C is preferably formed in a range that occupies 3 to 80% of the area of the lower surface of the ceramic multilayer substrate 2. The ceramic multilayer substrate 2 is usually formed of glass ceramics, and since the glass ceramics has a surface roughness Rmax (several μm) comparable to that of the copper foil, the bonding force with the resin laminate 3 is weak. The sintered metal forming the electrode 4C has a surface roughness Rmax of several tens of μm and an order of magnitude higher than the surface roughness of the copper foil of several μm. Can be increased. The difference in surface roughness is that the copper foil is formed by plating or rolling a copper plate, whereas the sintered metal contains a conductive paste containing 10 to 40% by volume of a resin called varnish. Since it is formed by baking, the resin component is burned away, leaving voids inside and on the surface and increasing the surface roughness.

  The electrode 4C may be formed as a ground electrode or a dummy electrode. When the electrode 4C is formed as a ground electrode, by providing a ground electrode at the interface between the ceramic multilayer substrate 2 and the resin laminate 3, a ceramic multilayer substrate 2 and a mother board (not shown) such as a printed wiring board. ) Can be electrically shielded. Further, by configuring the electrode 4C as the ground electrode of the ceramic multilayer substrate 2, the connection distance to the ground electrode of the motherboard can be shortened, and the parasitic inductance value can be reduced. Good high frequency characteristics can be obtained when used as a high frequency component. The electrode 4C is ideally formed on the lower surface of the resin laminate 3. However, when other wiring is arranged on the mother board side in high-density mounting, a measurement hole (probe after mounting) Since there is a case where it is vacant and it is difficult to substantially provide it on the lower surface of the resin laminate 3, it is interposed at the interface between the ceramic multilayer substrate 2 and the resin laminate 3.

  Needless to say, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, a three-layer resin laminate has been described as an example. However, the resin laminate in the present invention may be two layers or four or more layers.

  The present invention can be suitably used for a composite multilayer substrate on which active elements such as semiconductor elements and passive elements such as capacitors are mounted as chip components.

It is sectional drawing which shows one Embodiment of the composite multilayer substrate of this invention. (A)-(g) is process drawing which shows the process of producing the 1st resin layer of the composite multilayer substrate shown in FIG. 1, respectively. (A), (b) is process drawing which shows the process of joining the ceramic multilayer substrate and resin laminated body of a composite multilayer substrate which are respectively shown in FIG. It is sectional drawing which shows other embodiment of the composite multilayer substrate of this invention.

Explanation of symbols

1 Composite multilayer substrate 2 Ceramic multilayer substrate (ceramic substrate)
3 resin laminate 3A, 3B, 3C resin layer 4 circuit pattern 4C electrode 5 chip part 6C external terminal electrode

Claims (6)

  A ceramic substrate having a first main surface and a second main surface facing the first main surface; and a resin laminate having a first main surface and a second main surface facing the first main surface; 2 and the first main surface of the resin laminate, and a circuit pattern formed on the ceramic substrate and an external terminal formed on the second main surface of the resin laminate A composite multilayer substrate electrically connected to an electrode, wherein each resin layer constituting the resin laminate has a different degree of cure, and a degree of cure on the second main surface side of the resin laminate. Is lower than the degree of cure on the first main surface side. The composite multilayer substrate according to claim 1, wherein the resin layer on the second main surface side of the resin laminate is in a semi-cured state . Each resin layer, a composite multi-layer substrate according to claim 1 or claim 2, characterized in that each include a resin material and an inorganic powder. The ceramic substrate is made of a ceramic multilayer substrate obtained by laminating a plurality of ceramic layers, the ceramic multilayer substrate, according to claim 1 to claim 3, characterized in that it comprises a circuit pattern mainly composed of Ag or Cu therein The composite multilayer substrate according to any one of claims. 5. The composite multilayer substrate according to claim 1 , wherein the external terminal electrode is formed of a metal foil. The composite multilayer substrate according to claim 1 , wherein the resin laminate includes a chip component.

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