Patent ID: 12218085

DESCRIPTION OF EMBODIMENTS

Hereinafter, aspects for implementing the present technique (hereinafter referred to as embodiments) will be described. The description will be made in the following order.1. First embodiment (example in which heat storage material is disposed in rigid substrate)2. Second embodiment (example in which heat storage material is disposed in flexible substrate)3. Third embodiment (example in which core material or the like including heat storage material is disposed in rigid substrate)

1. First Embodiment

[Configuration Example of Electronic Device]

FIG.1is a diagram showing a configuration example of an electronic device100according to a first embodiment of the present technique. This electronic device100includes a semiconductor chip110and a mounting substrate200.

The semiconductor chip110includes a solid-state imaging element111, external terminals (not shown), and the like. The solid-state imaging element111captures image data by photoelectric conversion. For the solid-state imaging element111, for example, a complementary metal oxide semiconductor (CMOS) imaging element or the like is used. Also, although the solid-state imaging element111is disposed in the semiconductor chip110, the present technique is not limited to this configuration, and a semiconductor integrated circuit other than the solid-state imaging element111can be disposed.

The mounting substrate200is a rigid substrate on which the semiconductor chip110is mounted and includes various circuits such as a digital signal processor210. The digital signal processor210performs predetermined signal processing on the image data. This digital signal processor210exchanges the image data and control signals with the solid-state imaging element111via a signal line109. Also, although the digital signal processor210is disposed in the mounting substrate200, the present technique is not limited to this configuration, and a circuit other than the digital signal processor210can be disposed.

FIG.2is an example of a cross-sectional view of the electronic device100according to the first embodiment of the present technique. The semiconductor chip110is mounted on one of both surfaces of the mounting substrate200by wire bonding. Hereinafter, a surface on which the semiconductor chip110is mounted is referred to as a “front surface,” and a surface on which the semiconductor chip110is not mounted is referred to as a “back surface.” Also, mounting of the semiconductor chip110is not limited to the wire bonding, and for example, flip chip mounting can also be used. In addition, components other than the semiconductor chip110can further be mounted.

Further, a predetermined direction parallel to the front surface of the mounting substrate is defined as an “X direction,” and a direction perpendicular to the front surface is defined as a “Z direction.” A direction perpendicular to the X and Z directions is defined as a “Y direction.” The figure is a cross-sectional view seen in the Y direction.

Also, the front surface of the mounting substrate200is coated with a solder resist221and the back surface of the mounting substrate200is coated with a solder resist222.

Further, the mounting substrate200includes a wiring layer230to which a signal line240is wired. The wiring layer230includes a core material231, prepregs232and233, the signal line240, heat storage materials251to259, and copper foils271to274.

The core material231is a member disposed in the vicinity of a center of the mounting substrate200and includes an insulating material. The copper foils272and273are laminated on both surfaces of the core material231.

The prepregs232and233are members for connecting copper foils such as the copper foils271to274and include insulating materials. For the prepregs232and233, for example, members obtained by impregnating a glass cloth, which is a covering made of glass, with a resin called resin and covering its top and bottom with a thin resin are used. The prepreg232is disposed between the copper foil271and the copper foil272above the core material231with a direction toward the front surface of the mounting substrate200set as an upward direction. On the other hand, the prepreg233is disposed between the copper foil273and the copper foil274below the core material231.

As described above, in the mounting substrate200, the solder resist221, the copper foil271, the prepreg232, the copper foil272, the core material231, the copper foil273, the prepreg233, the copper foil274, and the solder resist222are laminated in order from a top thereof. The substrate in which copper foils are applied to a laminated board on which prepregs are stacked in this way is called a copper-clad laminated board.

Further, the signal line240is connected to the semiconductor chip110via the signal line109, and is also connected to the copper foil271or the like. In addition, a portion of the signal line240extending in the Z direction is called a via. This signal line240and the copper foils271to274are used as a transmission line for transmitting a predetermined electrical signal (image data or the like) from the semiconductor chip110. Various circuits such as the digital signal processor210are formed by this transmission line. Also, the signal line240and the copper foils271to274are an example of the transmission line described in the claims.

Further, the heat storage materials251to259are embedded in the wiring layer230. These heat storage materials251to259are members that have higher thermal conductivities than the insulating materials constituting the core material231and the prepregs232and233and accumulate latent heat accompanying phase transition that occurs within an operating temperature range of the semiconductor chip110. The heat storage material that accumulates latent heat in this way is called a latent heat storage material.

Here, the latent heat is thermal energy generated or absorbed when phase transition of an object occurs without change in temperature of the object. In addition, the phase transition also means, in addition to a change of state between a gas, a liquid and a solid, a change of physical properties (crystal structure, density, magnetism, etc.) or a change of ground state of a substance in the same phase. This phase transition is also called a phase change.

Further, shapes and sizes of the heat storage materials251to259are arbitrary. The heat storage material251is disposed directly below the solder resist221and the heat storage material259is disposed directly above the solder resist222. The heat storage materials252to258are disposed in a region in which at least some of the heat storage materials252to258comes into contact with the transmission line (signal line240or the like). Further, a part of the heat storage material254is filled into a through hole extending in the Z direction. This part can be called a thermal via.

For the heat storage material251and the like, vanadium oxides, paraffin-based heat storage materials, phase change material (PCM) sheets, or the like are used. Their thermal conductivities are, for example, 10 to 250 watts per meter Kelvin (W/m·K). Also, the latent heat is, for example, 50 to 510 joules per gram (J/g). The heat storage materials such as vanadium oxides are used for heating and cooling houses and for keeping warm and cold during transportation.

Vanadium oxides are solid at room temperature, are relatively easy to handle if powdered, and have greater latent heat than a paraffin-based heat storage material. On the other hand, vanadium oxides have a higher density than a paraffin-based heat storage material, and in a case in which they is disposed on the mounting substrate200, insulation is required depending on a location. Further, the paraffin-based heat storage material changes from a solid to a gel state at a high temperature such as 80° C. or higher, but if it is encapsulated in microcapsules, it can be easily handled. In addition, the paraffin-based heat storage material encapsulated in a microcapsule is also called a thermomemory.

Further, a material of the transmission line (the signal line240, the copper foil271, etc.) is a metal such as copper, and a material of the insulating materials constituting the core material231and the prepregs232and233is glass or a resin. These metals, glass, and resin do not undergo phase transition within a general operating temperature range of the semiconductor chip110, and within that temperature range, sensible heat is generated instead of latent heat. Sensible heat is thermal energy generated or absorbed when a temperature of an object changes without phase transition.

In summary of the above-mentioned configuration, in the mounting substrate200which is a rigid substrate, the transmission line such as the signal line240and the copper foil271are wired in the wiring layer230in which the prepreg232and the core material231including the insulating materials are disposed. This transmission line transmits an electrical signal from the semiconductor chip110. Further, the heat storage materials251to259that have higher thermal conductivities than the insulating materials and accumulate latent heat accompanying phase transition that occurs within the operating temperature range of the semiconductor chip110are further disposed in the wiring layer230. With this configuration, the heat generated in the semiconductor chip110is conducted to the heat storage material251and the like via the transmission line and absorbed.

FIG.3is an example of a cross-sectional view of the wiring layer according to the first embodiment of the present technique.FIG.3is an example of a cross-sectional view of the wiring layer230taken along line segment X1-X2inFIG.2and viewed in the Z direction. As illustrated inFIG.3, in the prepreg232and the like, a via that functions as the signal line240is wired, and the heat storage material254is embedded in a region in which at least a part is in contact with the signal line240(for example, a region surrounding the signal line240).

FIG.4is a diagram for explaining heat dissipation performance of the first embodiment of the present technique. Arrows in the figure indicate directions in which heat conducts. As illustrated in the figure, when heat is generated in the semiconductor chip110, the transmission line such as the signal line240conducts the heat. As described above, the thermal conductivity of the heat storage material (251, etc.) is higher than those of the insulating materials. For this reason, most of the heat is conducted from the transmission line to the heat storage materials.

Further, the heat storage materials undergo phase transition within the operating temperature range of the semiconductor chip110, and the latent heat accompanying the phase transition is accumulated. In other words, the heat storage materials absorb thermal energy corresponding to the latent heat. Also, the thermal energy absorbed by the heat storage materials is released to the back surface side of the mounting substrate200via the transmission line with the elapse of time.

As described above, the heat generated in the semiconductor chip110is conducted from the transmission line to the heat storage materials, and the heat storage materials absorb the heat during the phase transition, and thus an amount of heat radiated from the semiconductor chip110increases as compared with a case in which the heat storage materials are not provided. As a result, it is possible to inhibit a temperature rise of the semiconductor chip110and prevent thermal runaway of the semiconductor chip110due to the temperature rise.

Also, since the heat storage materials absorb the heat during the phase transition without the temperature being raised, a temperature rise of the mounting substrate200can be inhibited as compared with the case in which the heat storage materials are not provided. Further, by disposing the heat storage materials in a dispersed manner in the mounting substrate200, a heat distribution of the mounting substrate200can be made uniform and an internal stress can be relaxed at the time of thermal expansion. By inhibiting the temperature rise and making the heat distribution uniform, it is possible to prevent the mounting substrate200from being warped due to the temperature rise. By preventing warpage, deterioration of imaging characteristics of the solid-state imaging element111can be inhibited. In particular, as a size of the solid-state imaging element111increases, the effect of inhibiting deterioration of imaging characteristics increases.

By increasing a volume and an area of a metal (copper or the like) transmission line (signal line240or the like), an amount of heat dissipated from the semiconductor chip110can also be increased. However, as an amount of metal constituting the transmission line increases, a leakage current increases, which may increase power consumption and weight. For this reason, it is not preferable to increase the number of transmission lines.

The heat storage materials are thinner and lighter than the metal constituting the transmission line, and thus by improving the heat dissipation performance with the heat storage materials, it is possible to easily reduce a density of the wiring, and a size and a weight of the imaging element.

[Method for Manufacturing Mounting Substrate]

FIGS.5A,5B,5C, and5Dare diagrams for explaining a process until desmearing according to the first embodiment of the present technique. In the figure, a is a diagram for explaining a process of forming through holes, and in the figure, b is a diagram for explaining processes of copper-plating and forming an inner layer circuit. In the figure, c is a diagram for explaining processes of forming the heat storage materials and lamination pressing, and in the figure, d is a diagram for explaining a process from drilling to desmearing.

As illustrated in a of the figure, a manufacturing system forms through holes for conduction in an inner layer (that is, the core material231) by drilling or laser machining.

Next, as illustrated in b of the figure, the manufacturing system performs copper-plating on an inner wall of the through hole and a front surface of the core material231to form an inner layer circuit.

Subsequently, as illustrated in c of the figure, the prepregs232and233are laminated, and the heat storage material252and the like are disposed inside them, on upper surfaces and lower surfaces thereof. Then, the manufacturing system melts and cures the laminated resins of the prepregs232and233by thermocompression bonding to prepare a multilayer substrate.

Here, as a method for forming the heat storage materials, an appropriate method is selected in accordance with a type of the heat storage materials. In the case of using vanadium oxides or paraffin-based heat storage materials, the manufacturing system mixes their microcapsules and powders with an epoxy resin or the like, prints and applies it to a circuit surface, the prepreg232, or the like with a screen printing machine or a dispenser, and cures the resin. In addition to applying and printing, when a lay-up is performed at the time of laminating the prepregs232and233, the heat storage materials are sandwiched between the prepreg232and the like, or overlapped on the upper and lower surfaces thereof, and thus they can be formed at arbitrary positions. In this case, the manufacturing system may prepare a flexible PCM sheet as a heat storage material, cut it into an arbitrary shape using a cutter, a hollow, or the like, and dispose it on the circuit surface, above, below and in the middle of the prepreg232and the like in the lay-up of the laminating process.

Then, as illustrated in d of the figure, the manufacturing system forms through holes and non-through holes in the laminated substrate by drilling or laser processing. The manufacturing system cleans the inside of the holes by performing a process of dissolving and removing unnecessary deposits (that is, desmearing) such as a resin remaining inside the holes formed in the laminated substrate with a plasma, a chemical solution, or the like.

FIGS.6A and6Bare diagrams for explaining a process until visual inspection according to the first embodiment of the present technique. In the figure, a is a diagram for explaining a process from formation of an outer layer circuit to formation of the heat storage materials, and in the figure, b is a diagram for explaining a process from formation of the solder resists to visual inspection.

As illustrated in a of the figure, the manufacturing system performs copper-plating on the holes formed in the laminated substrate and outer layers (the prepregs232and233, etc.) of the laminated substrate and electrically connects the copper-plated portions to the inner layer circuit. Then, the manufacturing system wires the signal line240to the outer layer by etching or an additive method to form the outer layer circuit. Subsequently, the manufacturing system disposes the heat storage material257and the like on the holes formed in the laminated substrate and the outer layer circuit. In a case in which the heat storage materials are formed, an appropriate method is selected in accordance with a type of the heat storage materials, and coating, printing, or the like is used. When they are disposed directly below or directly above the solder resists221and222, coating, printing, laminating, pasting, or the like is used.

Then, as illustrated in b of the figure, the manufacturing system forms the solder resists221and222on the front surface and the back surface of the outer layer circuit. For a method for forming the solder resists221and222, screen printing, roll coating, spray coating, or the like is used. In addition, the manufacturing system cures solder resist ink by thermosetting, ultra-violet (UV) curing, or the like.

The manufacturing system performs gold-plating on necessary lands for the purposes of wire bonding, soldering, formation of contacts and terminals, or the like. Also, if the purpose of wire bonding or the like can be achieved, processing other than gold-plating can be performed. Then, the manufacturing system performs outer shape processing on the laminated substrate to have a predetermined shape by router processing, outer shape pressing, or the like. In addition, the manufacturing system electrically inspects whether or not connections electrically necessary for circuits and conduction holes are performed, and whether there is a breakage or a short-circuit in the circuits. Finally, the manufacturing system visually inspects, using an inspection machine or the like, whether or not an appearance of the mounting substrate200is finished in accordance with standards. This visual inspection may be performed visually by an operator.

FIG.7is a flowchart showing an example of a method for manufacturing the mounting substrate200according to the first embodiment of the present technique. The manufacturing system forms the through holes for conduction in the inner layer (step S901). The manufacturing system performs copper-plating (step S902) to form the inner layer circuit (step S903). Then, the manufacturing system forms the heat storage materials (step S904), melts and cures the resins of the prepregs232and233by thermocompression bonding, and prepares the multilayer substrate (step S905).

Next, the manufacturing system forms the through holes and the non-through holes in the laminated substrate (steps S906and S907) and performs desmearing (step S908). The manufacturing system performs copper-plating on the holes formed in the laminated substrate and the outer layer of the laminated substrate are (step S909) to form the outer layer circuit (step S910).

Subsequently, the manufacturing system forms the heat storage material257and the like on the holes formed in the laminated substrate and the outer layer circuit (step S911). The manufacturing system forms the solder resists221and222on the front and back surfaces of the outer layer circuit (step S912) and performs gold-plating on necessary lands (step S913). Also, if the purpose of wire bonding or the like can be achieved, processing other than gold-plating can be performed. Then, the manufacturing system performs outer shape processing on the laminated substrate (step S914). Further, the manufacturing system performs an electrical inspection (step S915) and a visual inspection (step S916). After step S916, the manufacturing system ends the manufacturing of the mounting substrate200. Also, some of these manufacturing processes can be performed by an operator instead of the manufacturing system.

As described above, according to the first embodiment of the present technique, the heat storage material251and the like, which have higher thermal conductivities than the insulating materials and accumulate the latent heat accompanying the phase transition are disposed, and thus the heat generated in the semiconductor chip110can be conducted and absorbed by the heat storage material251and the like. As a result, the heat dissipation performance of the electronic device100can be improved while an increase in the amount of metal is inhibited.

2. Second Embodiment

In the first embodiment described above, a rigid substrate is used for the mounting substrate200, but since the rigid substrate cannot be bent, three-dimensional wiring in the device may be difficult. The electronic device100of a second embodiment is different from that of the first embodiment in that the heat storage materials are disposed on a flexible substrate.

FIG.8is an example of a cross-sectional view of a mounting substrate201according to the second embodiment of the present technique. In the electronic device100of the second embodiment, the mounting substrate201is disposed instead of the mounting substrate200. For the mounting substrate201, a flexible substrate is used.

The mounting substrate201includes a cover lay225, a heat storage material251, a signal line240, and a base layer280. Also, although components such as the semiconductor chip110are mounted on the mounting substrate201, the semiconductor chip110is omitted in the figure.

The base layer280is a thin film-shaped insulating material, and polyimide or the like is used. The base layer280is also called a base film. In the base layer280, a signal line240is wired and a heat storage material251is disposed. A front surface of the base layer280is covered with the cover lay225.

At the time of manufacturing the substrate, the manufacturing system forms a circuit formed by the signal line240on the base layer280and disposes the heat storage material251by pasting, printing or coating. Then, the manufacturing system performs thermocompression bonding of the cover lay225. Further, a solder resist can be disposed instead of the cover lay225.

Since the heat storage material251absorbs latent heat, it is possible to improve heat dissipation performance of components mounted on the mounting substrate201(that is, the flexible substrate) as in the first embodiment.

Also, although a flexible substrate is used for the mounting substrate201, the present technique is not limited to this configuration. A flex rigid substrate formed by combining a flexible substrate with a rigid substrate can also be used for the mounting substrate. In the case of a flex rigid substrate, for example, the semiconductor chip110is mounted on the rigid substrate, and the heat storage material251and the signal line240are disposed on the flex substrate or the rigid substrate.

As described above, according to the second embodiment of the present technique, the heat storage material251is disposed on the flexible substrate, and thus when three-dimensional wiring is performed with the flexible substrate, heat dissipation performance of the substrate can be improved.

3. Third Embodiment

In the first embodiment described above, the manufacturing system has disposed the heat storage materials251to259in the wiring layer230, but it is necessary to further carry out a process of disposing the heat storage material251and the like as compared with the case in which they are not disposed. A mounting substrate of a third embodiment is different from that of the first embodiment in that a process of forming the heat storage material is unnecessary.

FIG.9is an example of a cross-sectional view of the electronic device100according to the third embodiment of the present technique. The electronic device100of the third embodiment is different from that of the first embodiment in that a mounting substrate202is provided instead of the mounting substrate200.

The mounting substrate202includes solder resists223and224instead of the solder resists221and222. Also, the mounting substrate202includes a core material235instead of the core material231and prepregs236and237instead of the prepregs232and233.

The solder resists223and224are obtained by mixing a heat storage material with solder resist ink or the like. Further, the core material235and the prepregs236and237are obtained by mixing a heat storage material with an insulating material such as a varnish or a silane coupling material. That is, the solder resists223and224, the core material235, and the prepregs236and237further include a heat storage material in addition to the insulating material and the solder resist ink.

The solder resist ink used for the solder resists223and224includes a two-component type in which a main agent and a curing agent are mixed immediately before use and a one-component type in which the main agent and curing agent are already mixed by an ink manufacturer. Examples of a method for applying the solder resists223and224include screen printing, roll coating, spraying, and curtain coating. A viscosity of the ink is adjusted in accordance with the coating method. Specifically, the manufacturing system uses a stirrer to put the solder resist ink in a container and stirs the container while rotating the container with a spatula or the like in the container. In this case, microcapsules and powder of a heat storage material such as paraffin or vanadium oxide are added at the same time and mixed with the solder resist ink. As a result, the solder resists223and224having a heat storage function can be formed by using a normal solder resist manufacturing process.

The heat storage material mixed with the solder resist223and the like or the core material235and the like in the second embodiment has the same function as that of the first embodiment. That is, the heat storage material has a higher thermal conductivity than the insulating material and accumulates latent heat accompanying phase transition. For this reason, even in the second embodiment, the heat dissipation performance can be improved as in the first embodiment.

FIG.10is a diagram for explaining a method for manufacturing a glass cloth according to the third embodiment of the present technique. The manufacturing system performs processes of warping and gluing, drawing, weaving and heat cleaning. These processes are omitted in the figure. Details of these processes are described in, for example, “Seizo hoho(Manufacturing method),” [online], Nitto Boseki Co., Ltd., [Search on Apr. 2, 2019], Internet (URL: https://www.nittobo.co.jp/business/glassfiber/about/process.htm).”

As illustrated in the figure, after heat cleaning, the manufacturing system performs secondary degreasing, transports glass fibers using an accumulator311, and immerses them in a surface processing solution tank312containing a silane coupling material. Then, the manufacturing system heats the glass fibers in a heating furnace313, transports them using an accumulator314, and performs a processing to complete the glass cloth. In this process, the manufacturing system can mix the heat storage material with the silane coupling material in the surface processing solution tank312.

FIGS.11A,11B,11C,11D, and11Eare diagrams for explaining a method for manufacturing the mounting substrate202according to the third embodiment of the present technique. In the figure, a is a diagram for explaining a manufacturing process of a varnish, and in the figure, b is a diagram for explaining a manufacturing process of prepregs. In the figure, c is a diagram for explaining a process of laminating copper foils, and in the figure, d is a diagram for explaining a process of heating and pressing using a pressing machine. In the figure, e is a diagram showing an example of a copper-clad laminate.

As illustrated in a of the figure, the manufacturing system manufactures the varnish by stirring a resin, a curing agent, or the like with a stirrer321or the like. In this process, the manufacturing system can further mix the heat storage material in addition to the resin and the like.

Next, as illustrated in b of the figure, the manufacturing system applies the varnish to the glass cloth, immerses it in an impregnated pad322, and dries it with a heater323. Then, the manufacturing system cuts the glass cloth into a sheet shape using a cutter324and laminates them. As a result, the prepregs236and237are manufactured. In this process, the manufacturing system can form the heat storage material on surfaces of the prepregs by roll coating, printing, or the like.

Subsequently, as illustrated in c of the figure, the manufacturing system superimposes the copper foils271and272on both surfaces of the prepregs.

As illustrated in d of the figure, the manufacturing system heats and pressurizes the prepregs on which the copper foils are laminated by the pressing machine326. As a result, a copper-clad laminate can be manufactured as illustrated in e of the figure.

As illustrated inFIGS.10,11A,11B,11C,11D, and11E, the prepregs can be manufactured by mixing the heat storage material with the insulating material. Specifically, as illustrated inFIG.10, the heat storage material can be mixed with the silane coupling material. Also, as illustrated inFIG.11A, the heat storage material can be mixed with the varnish. As illustrated inFIG.11B, the heat storage material can also be applied to surfaces of the dried prepregs. All of these three methods can be used, or only one or two can be used. Further, the core material can also be manufactured by the same method as that of the prepregs.

Also, the manufacturing system mixes the heat storage material with all of the core material, the prepregs, and the solder resists, but it is also possible to mix the heat storage material with only one or two of these.

FIGS.12A,12B, and12Care diagrams for explaining a process until formation of the through holes according to the third embodiment of the present technique.FIG.12Ais a diagram for explaining a process of forming the through holes, andFIG.12Bis a diagram for explaining processes of copper plating and forming the inner layer circuit.FIG.12Cis a diagram for explaining a process from formation of the heat storage material and lamination pressing to via processing.

As illustrated in a of the figure, the manufacturing system forms the through holes for conduction in the inner layer (core material235) by drilling or laser machining.

Next, as illustrated in b of the figure, the manufacturing system performs copper-plating on inner walls of the through holes and a surface of the core material235to form the inner layer circuit.

Subsequently, as illustrated in c of the figure, the prepregs236and237are laminated, melted and cured by thermocompression bonding to prepare the multilayer substrate. Then, the manufacturing system forms the through holes and the non-through holes in the laminated substrate by drilling or laser machining.

The core material235, the prepreg236, and the like in the figure are manufactured by the manufacturing methods illustrated inFIGS.10,11A,11B,11C,11D and11E, and the heat storage material is mixed.

FIGS.13A and13Bare diagrams for explaining a process until visual inspection of the third embodiment of the present technique. In the figure, a is a diagram for explaining a process from desmearing to formation of the outer layer circuit, and in the figure, b is a diagram for explaining a process from formation of the solder resists223and224to visual inspection.

As illustrated in a of the figure, the manufacturing system cleans the inside of the holes by performing a process of dissolving and removing unnecessary deposits (desmearing) such as a resin remaining inside the holes formed in the laminated substrate with a plasma, a chemical solution, or the like. Then, the manufacturing system performs copper-plating on the holes formed in the laminated substrate and the outer layer of the laminated substrate and electrically connects copper-plated portions to the inner layer circuit. Then, the manufacturing system wires the signal line240to the outer layer by etching or an additive method to form the outer layer circuit.

Next, as illustrated in b of the figure, the manufacturing system forms the solder resists223and224on the front surface and the back surface of the outer layer circuit. The manufacturing system performs gold-plating on necessary lands for the purposes of wire bonding, soldering, formation of contacts and terminals, or the like. Also, if the purpose of wire bonding or the like can be achieved, processing other than gold-plating can be performed. Then, the manufacturing system performs outer shape processing on the laminated substrate to have a predetermined shape by router processing, outer shape pressing, or the like. In addition, the manufacturing system electrically inspects whether or not connections electrically necessary for circuits and conduction holes are performed. Finally, the manufacturing system inspects whether or not an appearance of the mounting substrate202is finished in accordance with standards using an inspection machine or the like.

FIG.14is a diagram showing an example of a composition of the solder resist according to the third embodiment of the present technique. As illustrated in the figure, the solder resist includes, for example, a resin, a filler, a color pigment, a catalyst, an additive, and a solvent. A proportion of a weight of the filler among these is about 20 to 25%. By adding microcapsules or powder of the heat storage material such as paraffin or vanadium oxide to the filler component, the solder resist ink itself can be imparted with a heat storage function. This makes it possible to manufacture the solder resists223and224that can store heat. Also, a particle size of the heat storage material added to the solder resist ink is preferably 2 micrometers (μm) or less.

FIG.15is a flowchart showing an example of a method for manufacturing the mounting substrate202according to the third embodiment of the present technique. The manufacturing method of the third embodiment is different from the first embodiment in that the processes of forming the heat storage material (steps S904and S911) are not executed. In the third embodiment, since the solder resist223and the like including the heat storage material are used, the processes of forming the heat storage material (step S904or the like) can be reduced as compared with the first embodiment.

As described above, in the third embodiment of the present technique, the solder resist223and the like including the heat storage material, the core material235and the prepreg236and the like are disposed, and thus when the mounting substrate202is manufactured, the process of disposing the heat storage material becomes unnecessary. This makes it possible to simplify the manufacturing process of the mounting substrate202.

Also, the above-described embodiments show examples for embodying the present technique, and matters in the embodiments and matters specifying the invention in the claims have a corresponding relationship with each other. Similarly, the matters specifying the invention in the claims and the matters in the embodiments of the present technique having the same name have a corresponding relationship with each other. However, the present technique is not limited to the embodiments and can be embodied by applying various modifications to the embodiments without departing from the gist thereof.

In addition, the effects described in the present specification are merely examples and are not intended as limiting, and other effects may be obtained.

Further, the present technique can have the following configurations.

(1) A substrate including:

a transmission line configured to transmit a predetermined electrical signal from a semiconductor chip;an insulating material to which the transmission line is wired; anda heat storage material that has a higher thermal conductivity than the insulating material and accumulates latent heat accompanying phase transition that occurs within an operating temperature range of the semiconductor chip.
(2) The substrate according to the above (1),wherein the substrate includes a flexible substrate,the transmission line is wired to a base layer, andthe base layer includes the insulating material.
(3) The substrate according to the above (1) or (2),wherein the substrate includes a rigid substrate, andthe transmission line is wired to a wiring layer in which a core material and a prepreg are disposed.
(4) The substrate according to the above (3),wherein the heat storage material is further disposed on the wiring layer, andthe core material and the prepreg include the insulating material.
(5) The substrate according to the above (3) or (4), wherein the prepreg includes the insulating material and the heat storage material.
(6) The substrate according to one of the above (3) to (5), wherein the core material includes the insulating material and the heat storage material.
(7) The substrate according to one of the above (3) to (6), further including a solder resist configured to cover a surface of the substrate, wherein the solder resist includes the heat storage material.
(8) An electronic device including:a semiconductor chip;a transmission line configured to transmit a predetermined electrical signal from the semiconductor chip;an insulating material to which the transmission line is wired; anda heat storage material that has a higher thermal conductivity than the insulating material and accumulates latent heat accompanying phase transition that occurs within an operating temperature range of the semiconductor chip.
(9) A method for manufacturing a substrate, the method including:disposing a heat storage material that has a higher thermal conductivity than an insulating material and accompanies phase transition that occurs within an operating temperature range of a semiconductor chip; andwiring a transmission line configured to transmit a predetermined electrical signal from the semiconductor chip to the insulating material.
(10) The method for manufacturing a substrate according to the above (9),wherein in the wiring, the transmission line is wired to a wiring layer in which a core material and a prepreg are disposed, andin the disposing of the heat storage material, the heat storage material is further disposed on the wiring layer.
(11) The method for manufacturing a substrate according to the above (9), further including coating a surface of the substrate with a solder resist,wherein at least one of the solder resist, the core material, and the prepreg contains the heat storage material,the core material and the prepreg include the insulating material,in the disposing of the heat storage material, at least one of the solder resist, the core material, and the prepreg is disposed, andin the wiring, the transmission line is wired to the wiring layer in which the core material and the prepreg are disposed.

REFERENCE SIGNS LIST

100Electronic device109,240Signal line110Semiconductor chip111Solid-state imaging element200,201,202Mounting substrate210Digital signal processor221to224Solder resist225Cover lay230Wiring layer231,235Core material232,233,236,237Prepreg251to259Heat storage material271to274Copper foil280Base layer311,314Accumulator312Surface processing solution tank313Heating furnace321Stirrer322Impregnated pad323Heater324Cutter326Press machine