Substrate, electronic device, and method of manufacturing substrate

Abstract

One object of the present invention is to improve heat dissipation of a wiring substrate while minimizing the increase in metal content. The substrate is provided with transmission lines, insulating material, and heat storage material. The transmission lines in the substrate, on which the transmission lines, insulating material, and heat storage material are provided, transmit a specified electrical signal from a semiconductor chip. The transmission lines transmitting the specified electrical signal from the semiconductor chip are wired within the insulating material. The heat storage material has a higher thermal conductivity than the insulating material on which the transmission lines are wired, and stores the latent heat resulting from phase changes occurring within the operating temperature range of the semiconductor chip.

Description

Technical Field

[0001] This technology relates to a substrate. More specifically, this technology relates to a substrate on which a semiconductor chip is mounted, an electronic device, and a method for manufacturing the substrate. Background Technology

[0002] In recent years, the performance of electronic devices has improved, and at the same time, the heat generated by electronic devices during operation has tended to increase. With the increase in heat generation, the likelihood of adverse effects (e.g., thermal runaway of mounting circuits and warping of the substrate) increases. Therefore, for example, an electronic device has been proposed in which the area of ​​the conductive pattern, which serves as a wiring pattern on the substrate, is increased, and the conductive pattern is used as a heat sink (e.g., see PTL 1).

[0003] [List of Citations]

[0004] [Patent Literature]

[0005] [PTL 1]

[0006] JP 2014-049604 A Summary of the Invention

[0007] [Technical Issues]

[0008] In the aforementioned conventional techniques, heat dissipation performance is improved by increasing the area of ​​the conductive pattern. However, when the area of ​​the conductive pattern (wiring) increases, the amount of metal constituting the wiring may increase, and due to the increased metal amount, power consumption and device weight may increase. If the amount of metal is reduced to suppress the increase in power consumption and weight, heat dissipation performance will decrease. As described above, in the aforementioned devices, it is difficult to improve heat dissipation performance while suppressing the increase in metal amount.

[0009] This technology is designed in view of this situation, with the aim of improving heat dissipation performance while suppressing the increase of metal content in the wiring substrate.

[0010] [Solution to the problem]

[0011] This technology is proposed to solve the aforementioned problems. Its first aspect is a substrate comprising: a transmission line configured to transmit a predetermined electrical signal from a semiconductor chip; an insulating material to which the transmission line is routed; and a heat storage material having a higher thermal conductivity than the insulating material and accumulating latent heat resulting from a phase change occurring within the operating temperature range of the semiconductor chip. This results in the heat generated by the semiconductor chip being absorbed by the heat storage material.

[0012] Furthermore, in the first aspect, the substrate may include a flexible substrate, the transmission lines may be routed to a base layer, and the base layer may include an insulating material. This results in the heat generated by the semiconductor chip mounted on the flexible substrate being absorbed by the heat storage material.

[0013] Furthermore, in the first aspect, the substrate may include a rigid substrate, and the transmission lines may be wired to a wiring layer, in which a core material and a prepreg material are disposed. This results in the effect that heat generated by the semiconductor chip mounted on the rigid substrate is absorbed by the heat storage material.

[0014] Furthermore, in the first aspect, the heat storage material can be further disposed on the wiring layer, and the core material and prepreg material can include insulating material. This results in the effect of absorbing heat in the heat storage material disposed separately from the core material and prepreg material.

[0015] Furthermore, in the first aspect, the prepreg material may include both insulating and heat-storing materials. This results in the effect of absorbing heat within the prepreg material.

[0016] Furthermore, in the first aspect, the core material may include both insulating and heat-storing materials. This results in the absorption of heat within the core material.

[0017] Furthermore, in the first aspect, a solder resist configured to cover the surface of the substrate can be provided, and the solder resist may include a heat storage material. This results in the effect of absorbing heat in the solder resist.

[0018] Furthermore, a second aspect of this technology is an electronic device comprising: 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 routed; and a heat storage material having a higher thermal conductivity than the insulating material and accumulating latent heat resulting from a phase change occurring within the operating temperature range of the semiconductor chip. This results in the heat generated by the semiconductor chip mounted on a substrate being absorbed by the heat storage material.

[0019] Furthermore, a third aspect of this technology is a method for manufacturing a substrate, the method comprising: a heat storage material placement step for placing a heat storage material having a higher thermal conductivity than an insulating material and accompanied by a phase transition occurring within the operating temperature range of a semiconductor chip; and a wiring step for wiring transmission lines to an insulating material, the transmission lines being configured to transmit a predetermined electrical signal from the semiconductor chip. This results in the effect of manufacturing a substrate having a heat storage material disposed thereon to absorb heat generated by the semiconductor chip.

[0020] Furthermore, in the third aspect, during the wiring step, the transmission line can be wired to a wiring layer, in which a core material and a prepreg material are disposed, and during the heat storage material placement step, the heat storage material can be further disposed on the wiring layer. This results in the effect of absorbing heat in the heat storage material, which is disposed separately from the core material and the prepreg material.

[0021] Furthermore, in a third aspect, a coating step of coating the substrate surface with solder resist can be provided. At least one of the solder resist, core material, and prepreg material may include a heat storage material. The core material and prepreg material may include insulating materials. In the heat storage material setting step, at least one of the solder resist, core material, and prepreg material can be set. In the wiring step, the transmission line can be wired to the wiring layer provided with the core material and prepreg material. This results in the effect of absorbing heat in at least one of the core material, prepreg material, and solder resist. Attached Figure Description

[0022] Figure 1 This is a block diagram illustrating an example configuration of an electronic device according to a first embodiment of the present technology.

[0023] Figure 2 This is an example of a cross-sectional view of an electronic device according to a first embodiment of the present technology.

[0024] Figure 3 This is an example of a cross-sectional view of a wiring layer according to a first embodiment of the present technology.

[0025] Figure 4 This is a diagram used to explain the heat dissipation performance of the first embodiment of the present technology.

[0026] Figure 5 This is a diagram illustrating the process up to descaling according to the first embodiment of the present technology.

[0027] Figure 6 This is a diagram illustrating the process up to visual inspection according to a first embodiment of the present technology.

[0028] Figure 7 This is a flowchart illustrating an example of a method for manufacturing a mounting substrate according to a first embodiment of the present technology.

[0029] Figure 8 This is an example of a cross-sectional view of a mounting substrate according to a second embodiment of the present technology.

[0030] Figure 9 This is an example of a cross-sectional view of an electronic device according to a third embodiment of the present technology.

[0031] Figure 10 This is a diagram illustrating a method for manufacturing glass cloth according to a third embodiment of the present technology.

[0032] Figure 11 This is a diagram illustrating a method for manufacturing and mounting a substrate according to a third embodiment of the present technology.

[0033] Figure 12 This is a diagram illustrating the process up to the formation of a through hole according to a third embodiment of the present technology.

[0034] Figure 13 This is a diagram illustrating the process up to visual inspection according to a third embodiment of the present technology.

[0035] Figure 14 This is a diagram illustrating an example of the composition of a solder resist according to a third embodiment of the present technology.

[0036] Figure 15 This is a flowchart illustrating an example of a method for manufacturing a mounting substrate according to a third embodiment of the present technology. Detailed Implementation

[0037] In the following text, aspects used to implement this technology (hereinafter referred to as embodiments) will be described. They will be described in the following order.

[0038] 1. First Embodiment (Example of heat storage material disposed in a rigid substrate)

[0039] 2. Second embodiment (example of heat storage material disposed in flexible substrate)

[0040] 3. Third embodiment (including an example in which the core material of the heat storage material, etc., is disposed in a rigid substrate)

[0041] <1. First Embodiment>

[0042] [Example of electronic device configuration]

[0043] Figure 1 This is a diagram illustrating an example configuration of an electronic device 100 according to a first embodiment of the present technology. The electronic device 100 includes a semiconductor chip 110 and a mounting substrate 200.

[0044] The semiconductor chip 110 includes a solid-state imaging element 111, external terminals (not shown), etc. The solid-state imaging element 111 captures image data through photoelectric conversion. For example, a complementary metal-oxide-semiconductor (CMOS) imaging element may be used for the solid-state imaging element 111. Furthermore, although the solid-state imaging element 111 is disposed in the semiconductor chip 110, the present technology is not limited to this configuration, and semiconductor integrated circuits other than the solid-state imaging element 111 may be disposed therein.

[0045] Mounting substrate 200 is a rigid substrate on which semiconductor chip 110 is mounted, and includes various circuits such as digital signal processor 210. Digital signal processor 210 performs predetermined signal processing on image data. This digital signal processor 210 exchanges image data and control signals with solid-state imaging element 111 via signal line 109. Furthermore, although digital signal processor 210 is disposed in mounting substrate 200, the technology is not limited to this configuration, and circuits other than digital signal processor 210 can be provided.

[0046] Figure 2 This is an example of a cross-sectional view of an electronic device 100 according to a first embodiment of the present technology. A semiconductor chip 110 is mounted on one of the two surfaces of a mounting substrate 200 via wire bonding. Hereinafter, the surface on which the semiconductor chip 110 is mounted is referred to as the "front side," and the surface on which the semiconductor chip 110 is not mounted is referred to as the "back side." Furthermore, the mounting of the semiconductor chip 110 is not limited to wire bonding; for example, flip-chip mounting may also be used. In addition, components other than the semiconductor chip 110 may be further mounted.

[0047] Furthermore, the predetermined direction parallel to the front side of the mounting substrate is defined as the "X direction," and the direction perpendicular to the front side is defined as the "Z direction." The direction perpendicular to both the X and Z directions is defined as the "Y direction." This figure is a cross-sectional view taken from the Y direction.

[0048] In addition, the front side of the mounting substrate 200 is coated with solder resist 221, and the back side of the mounting substrate 200 is coated with solder resist 222.

[0049] In addition, the mounting substrate 200 includes a wiring layer 230 to which signal lines 240 are wired. The wiring layer 230 includes a core material 231, prepreg materials 232 and 233, signal lines 240, heat storage materials 251 to 259, and copper foils 271 to 274.

[0050] The core material 231 is a component disposed near the center of the mounting substrate 200 and includes an insulating material. Copper foils 272 and 273 are laminated on both surfaces of the core material 231.

[0051] Prepreg materials 232 and 233 are components used to connect copper foils (e.g., copper foils 271 to 274) and include insulating material. For example, prepreg materials 232 and 233 are components obtained by impregnating glass cloth (a covering made of glass) with a resin called resin and covering its top and bottom with a thin layer of resin. Prepreg material 232 is disposed between copper foils 271 and 272 above core material 231, with its direction towards the front of mounting substrate 200 set upwards. On the other hand, prepreg material 233 is disposed between copper foils 273 and 274 below core material 231.

[0052] As described above, in the mounting substrate 200, solder resist 221, copper foil 271, prepreg material 232, copper foil 272, core material 231, copper foil 273, prepreg material 233, copper foil 274, and solder resist 222 are sequentially stacked from top to bottom. The substrate on which copper foil is applied to a laminate of prepreg materials stacked in this manner is called a copper-clad laminate.

[0053] Furthermore, signal line 240 is connected to semiconductor chip 110 via signal line 109, and also to copper foil 271, etc. Additionally, a portion of signal line 240 extending in the Z direction is referred to as a via. Signal line 240 and copper foils 271 to 274 serve as transmission lines for transmitting predetermined electrical signals (image data, etc.) from semiconductor chip 110. Various circuits, such as digital signal processor 210, are formed using this transmission line. Furthermore, signal line 240 and copper foils 271 to 274 are examples of transmission lines.

[0054] Furthermore, heat storage materials 251 to 259 are embedded in the wiring layer 230. These heat storage materials 251 to 259 are components with a higher thermal conductivity than the insulating materials constituting the core material 231 and the prepreg materials 232 and 233, and accumulate latent heat associated with phase changes occurring within the operating temperature range of the semiconductor chip 110. Heat storage materials that accumulate latent heat in this manner are called latent heat storage materials.

[0055] Here, latent heat is the thermal energy generated or absorbed when a substance undergoes a phase transition without a change in its temperature. Furthermore, a phase transition, besides signifying a change in state between gases, liquids, and solids, also implies a change in physical properties (crystal structure, density, magnetism, etc.) or a change in the ground state of substances in the same phase. This type of phase transition is also called a phase change.

[0056] Furthermore, the shape and size of the heat storage materials 251 to 259 are arbitrary. Heat storage material 251 is disposed directly below solder resist 221, and heat storage material 259 is disposed directly above solder resist 222. Heat storage materials 252 to 258 are disposed in at least some areas where they contact the transmission line (signal line 240, etc.). Additionally, a portion of the heat storage material 254 is filled into a through-hole extending along the Z-direction. This portion may be referred to as a thermally conductive via.

[0057] For thermal storage materials such as 251, vanadium oxide, paraffin-based thermal storage materials, and phase change material (PCM) sheets are used. For example, their thermal conductivity ranges from 10 to 250 watts (W / m·K) per meter Kelvin. Furthermore, their latent heat is, for example, 50 to 510 joules (J / g) per gram. Thermal storage materials such as vanadium oxide are used for heating and cooling in buildings, as well as for insulation and protection against cold during transportation.

[0058] Vanadium oxide is solid at room temperature, and if in powder form, it is relatively easy to handle and has a greater latent heat than paraffin-based thermal storage materials. On the other hand, vanadium oxide has a higher density than paraffin-based thermal storage materials, and when placed on the mounting substrate 200, insulation is required depending on the location. Furthermore, paraffin-based thermal storage materials change from a solid state to a gel state at high temperatures such as 80°C or higher, but can be easily handled if encapsulated in microcapsules. Moreover, paraffin-based thermal storage materials encapsulated in microcapsules are also referred to as thermal storage.

[0059] Furthermore, the transmission lines (signal line 240, copper foil 271, etc.) are made of metals, such as copper, and the insulating materials constituting the core material 231 and the prepreg materials 232 and 233 are made of glass or resin. These metals, glasses, and resins do not undergo phase transitions within the typical operating temperature range of the semiconductor chip 110, and within this temperature range, sensible heat is generated rather than latent heat. Sensible heat is the heat energy generated or absorbed when the temperature of an object changes without a phase transition.

[0060] In summary, in the mounting substrate 200, which serves as a rigid substrate, transmission lines such as signal lines 240 and copper foil 271 are routed in the wiring layer 230, which contains a core material 231 comprising an insulating material and a prepreg material 232. These transmission lines transmit electrical signals from the semiconductor chip 110. Furthermore, heat storage materials 251 to 259, having a higher thermal conductivity than the insulating material and accumulating latent heat associated with phase changes occurring within the operating temperature range of the semiconductor chip 110, are further disposed in the wiring layer 230. With this configuration, heat generated in the semiconductor chip 110 is conducted to the heat storage materials 251 and the like via the transmission lines and absorbed.

[0061] Figure 3 This is an example of a cross-sectional view of a wiring layer according to a first embodiment of the present technology. Figure 3It is along Figure 2 An example of a cross-sectional view of wiring layer 230 taken from line segment X1-X2 and viewed in the Z direction. (See example...) Figure 3 As shown, in the prepreg material 232, the guide hole used as the signal line 240 is wired, and the heat storage material 254 is embedded in at least a portion of the area in contact with the signal line 240 (e.g., the area surrounding the signal line 240).

[0062] Figure 4 This is a diagram illustrating the heat dissipation performance of a first embodiment of the present technology. The arrows in the diagram indicate the direction of heat conduction. As shown, when heat is generated in the semiconductor chip 110, transmission lines such as signal lines 240 conduct the heat. As described above, the thermal conductivity of the heat storage material (251, etc.) is higher than that of the insulating material. For this reason, most of the heat is conducted from the transmission lines to the heat storage material.

[0063] Furthermore, the heat storage material undergoes a phase transition within the operating temperature range of the semiconductor chip 110, and accumulates the latent heat accompanying the phase transition. In other words, the heat storage material absorbs thermal energy corresponding to the latent heat. Moreover, over time, the thermal energy absorbed by the heat storage material is released to the back side of the mounting substrate 200 via transmission lines.

[0064] As described above, the heat generated in the semiconductor chip 110 is conducted to the heat storage material via the transmission line, and the heat storage material absorbs heat during the phase transition. Therefore, the amount of heat radiated from the semiconductor chip 110 increases compared to the case where no heat storage material is provided. As a result, the temperature rise of the semiconductor chip 110 can be suppressed, and thermal runaway of the semiconductor chip 110 due to temperature rise can be prevented.

[0065] Furthermore, since the heat storage material absorbs heat without raising its temperature during the phase transition, the temperature rise of the mounting substrate 200 can be suppressed compared to the case where no heat storage material is provided. Moreover, by dispersing the heat storage material in the mounting substrate 200, the heat distribution of the mounting substrate 200 can be made uniform, and internal stress can be released during thermal expansion. By suppressing temperature rise and ensuring uniform heat distribution, warping of the mounting substrate 200 due to temperature rise can be prevented. By preventing warping, the deterioration of the imaging characteristics of the solid-state imaging element 111 can be suppressed. In particular, the effect of suppressing the deterioration of imaging characteristics increases with the increase of the size of the solid-state imaging element 111.

[0066] Increasing the volume and area of ​​the metal (copper, etc.) transmission lines (signal line 240, etc.) can also increase the heat dissipation from the semiconductor chip 110. However, as the amount of metal constituting the transmission lines increases, leakage current increases, which may increase power consumption and weight. Therefore, increasing the number of transmission lines is not preferable.

[0067] Thermal storage materials are thinner and lighter than the metals that make up the transmission lines, so by using thermal storage materials to improve heat dissipation, wiring density and the size and weight of imaging elements can be easily reduced.

[0068] [Manufacturing method of mounting substrate]

[0069] Figure 5 These are diagrams illustrating the process up to desmearing according to the first embodiment of the present invention. In the diagram, a is a diagram illustrating the process of forming a via, and b is a diagram illustrating the process of copper plating and forming inner layer circuitry. In this diagram, c is a diagram illustrating the process of forming the thermal storage material and lamination, and d is a diagram illustrating the process from drilling to desmearing.

[0070] As shown in Figure a, the manufacturing system forms through-holes for conduction in the inner layer (i.e., core material 231) by drilling or laser processing.

[0071] Next, as shown in Figure b, the manufacturing system performs copper plating on the inner wall of the through-hole and the front side of the core material 231 to form the inner layer circuit.

[0072] Subsequently, as shown in Figure c, prepreg materials 232 and 233 are laminated, and heat storage material 252 and the like are disposed on the upper and lower surfaces inside them. Then, the manufacturing system prepares a multilayer substrate by hot-pressing the laminated resin of prepreg materials 232 and 233 to melt and cure them.

[0073] Here, the appropriate method for forming the thermal storage material is selected according to the type of thermal storage material. When using vanadium oxide or paraffin-based thermal storage materials, the manufacturing system mixes its microcapsules and powder with epoxy resin, etc., prints and coats them onto the circuit surface, prepreg material 232, etc., using a screen printer or dispenser, and then cures the resin. Besides coating and printing, when laminating prepreg materials 232 and 233, the thermal storage material is sandwiched between prepreg materials 232, etc., or overlapped on the upper and lower surfaces of the prepreg materials 232, thus it can be formed at any location. In this case, the manufacturing system can prepare flexible PCM sheets as thermal storage materials, cut them into arbitrary shapes using a cutter, hollowing device, etc., and place them on the circuit surface, above, below, and in the middle of the prepreg material 232, etc., during the lamination process.

[0074] Then, as shown in d in 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 interior of the holes by performing a process using plasma, chemical solutions, etc., to dissolve and remove unwanted deposits such as resin remaining inside the holes formed in the laminated substrate (i.e., de-drilling).

[0075] Figure 6 This diagram illustrates the process up to visual inspection according to the first embodiment of the present technology. In the diagram, a is a diagram illustrating the process from the formation of the outer layer circuit to the formation of the heat storage material, and b is a diagram illustrating the process from the formation of the solder resist to visual inspection.

[0076] As shown in Figure a, the manufacturing system performs copper plating on the outer layers (prepreg materials 232 and 233, etc.) of the laminated substrate and on the holes formed in the laminated substrate, and electrically connects the copper-plated portions to the inner layer circuitry. Then, the manufacturing system routes signal lines 240 to the outer layer using etching or additive methods to form the outer layer circuitry. Subsequently, the manufacturing system places heat storage material 257, etc., on the holes formed in the laminated substrate and the outer layer circuitry. When forming heat storage material, a suitable method is selected according to the type of heat storage material, and coating, printing, etc., are used. When placed directly below or above the solder resist 221 and 222, coating, printing, lamination, bonding, etc., are used.

[0077] Then, as shown in Figure b, the manufacturing system forms solder resist 221 and 222 on the front and back sides of the outer layer circuit. Methods for forming solder resist 221 and 222 include screen printing, roll coating, and spraying. Furthermore, the manufacturing system cures the solder resist ink using thermosetting, ultraviolet (UV) curing, or similar methods.

[0078] The manufacturing system performs gold plating on necessary pads for purposes such as wire bonding, soldering, and forming contacts and terminals. Furthermore, if wire bonding and similar purposes can be achieved, processing other than gold plating can be performed. Then, the manufacturing system performs shaping processing on the laminated substrate using router processing, shape pressing, etc., to achieve a predetermined shape. In addition, the manufacturing system electrically inspects the circuits and conductive vias to ensure necessary electrical connections are made and to check for any damage or short circuits. Finally, the manufacturing system uses a visual inspection machine or similar device to visually inspect the appearance of the mounting substrate 200 to ensure it meets standards. This visual inspection can be performed by an operator.

[0079] Figure 7 This is a flowchart illustrating an example of a method for manufacturing a mounting substrate 200 according to a first embodiment of the present technology. The manufacturing system forms through-holes for conduction in the inner layers (step S901). The manufacturing system performs copper plating (step S902) to form inner layer circuitry (step S903). Then, the manufacturing system forms a heat storage material (step S904), melts and cures the resin of prepreg materials 232 and 233 by hot pressing, and prepares a multilayer substrate (step S905).

[0080] Next, the manufacturing system forms through-holes and non-through-holes in the laminate (steps S906 and S907) and performs de-drilling (step S908). The manufacturing system performs copper plating on the holes formed in the laminate and the outer layer of the laminate (step S909) to form the outer layer circuit (step S910).

[0081] Subsequently, the manufacturing system forms heat storage material 257 and the like on the holes formed in the laminated substrate and the outer layer circuit (step S911). The manufacturing system forms solder resist 221 and 222 on the front and back sides of the outer layer circuit (step S912) and performs gold plating on the necessary pads (step S913). Furthermore, if wire bonding or similar purposes can be achieved, processing other than gold plating can be performed. Then, the manufacturing system performs shape processing on the laminated substrate (step S914). In addition, the manufacturing system performs electrical inspection (step S915) and visual inspection (step S916). After step S916, the manufacturing system concludes the manufacturing of the mounting substrate 200. Furthermore, some of these manufacturing processes can be performed by an operator instead of the manufacturing system.

[0082] As described above, according to the first embodiment of this technology, a heat storage material 251 or the like, which has a higher thermal conductivity than insulating materials and accumulates latent heat during phase change, is provided. Therefore, the heat generated in the semiconductor chip 110 can be conducted and absorbed by the heat storage material 251 or the like. As a result, the heat dissipation performance of the electronic device 100 can be improved, while suppressing the increase in the amount of metal.

[0083] <2. Second Embodiment>

[0084] In the first embodiment described above, a rigid substrate is used to mount the substrate 200. However, since the rigid substrate cannot be bent, three-dimensional wiring in the device may be difficult. The electronic device 100 of the second embodiment differs from that of the first embodiment in that the heat storage material is disposed on a flexible substrate.

[0085] Figure 8 This is an example of a cross-sectional view of the mounting substrate 201 according to the second embodiment of the present technology. In the electronic device 100 of the second embodiment, the mounting substrate 201 is provided instead of the mounting substrate 200. A flexible substrate is used for the mounting substrate 201.

[0086] Mounting substrate 201 includes a cover layer 225, a heat storage material 251, a signal line 240, and a base layer 280. Furthermore, although components such as semiconductor chip 110 are mounted on mounting substrate 201, semiconductor chip 110 is omitted from the figure.

[0087] The base layer 280 is a thin-film insulating material, and may use polyimide or similar materials. The base layer 280 is also referred to as a base film. Signal lines 240 are routed within the base layer 280, and a heat storage material 251 is provided. The front side of the base layer 280 is covered by a cover layer 225.

[0088] During substrate manufacturing, the manufacturing system forms a circuit consisting of signal lines 240 on the base layer 280 and applies heat storage material 251 by pasting, printing, or coating. Then, the manufacturing system performs hot-press bonding of the cover layer 225. Alternatively, solder resist may be applied instead of the cover layer 225.

[0089] Since the heat storage material 251 absorbs latent heat, the heat dissipation performance of the components mounted on the mounting substrate 201 (i.e., the flexible substrate) can be improved, as in the first embodiment.

[0090] Furthermore, although a flexible substrate is used to mount substrate 201, the technology is not limited to this configuration. A flexible-rigid substrate formed by combining a flexible substrate with a rigid substrate can also be used as a mounting substrate. For example, in the case of a flexible-rigid substrate, a semiconductor chip 110 is mounted on a rigid substrate, and a heat storage material 251 and a signal line 240 are disposed on either the flexible substrate or the rigid substrate.

[0091] As described above, according to the second embodiment of the present technology, the heat storage material 251 is disposed on the flexible substrate, so when three-dimensional wiring is performed using the flexible substrate, the heat dissipation performance of the substrate can be improved.

[0092] <3. Third Embodiment>

[0093] In the first embodiment described above, the manufacturing system has already provided heat storage materials 251 to 259 in the wiring layer 230. However, compared to the case where heat storage materials 251 and the like are not provided, a further process of providing heat storage materials 251 and the like is required. The difference between the mounting substrate of the third embodiment and the mounting substrate of the first embodiment is that a process for forming heat storage materials is not required.

[0094] Figure 9 This is an example of a cross-sectional view of an electronic device 100 according to a third embodiment of the present technology. The electronic device 100 of the third embodiment differs from that of the first embodiment in that a mounting substrate 202 is provided instead of a mounting substrate 200.

[0095] Mounting substrate 202 includes solder resists 223 and 224 instead of solder resists 221 and 222. Furthermore, mounting substrate 202 includes core material 235 instead of core material 231 and prepreg materials 236 and 237 instead of prepreg materials 232 and 233.

[0096] Solder resists 223 and 224 are obtained by mixing the heat storage material with solder resist ink, etc. Furthermore, core material 235 and prepreg materials 236 and 237 are obtained by mixing the heat storage material with an insulating material (e.g., varnish or silane coupling material). That is, in addition to the insulating material and solder resist ink, solder resists 223 and 224, core material 235, and prepreg materials 236 and 237 also include a heat storage material.

[0097] Solder resist inks for solder resists 223 and 224 include two-component and one-component types. In the two-component type, the base agent and curing agent are mixed immediately before use, while in the one-component type, the base agent and curing agent have been mixed by the ink manufacturer. Examples of methods for applying solder resists 223 and 224 include screen printing, roller coating, spraying, and curtain coating. The viscosity of the ink is adjusted according to the coating method. Specifically, the manufacturing system uses a stirrer to place the solder resist ink into a container and stirs the container while rotating it with a scraper or similar tool. In this case, microcapsules and powdered heat storage materials, such as paraffin or vanadium oxide, are simultaneously added and mixed with the solder resist ink. As a result, solder resists 223 and 224 with heat storage functions can be formed using normal solder resist manufacturing processes.

[0098] In the second embodiment, the heat storage material mixed with solder resist 223 or core material 235 has the same function as in the first embodiment. That is, the heat storage material has a higher thermal conductivity than the insulating material and accumulates latent heat with the phase change. Therefore, even in the second embodiment, heat dissipation performance can be improved as in the first embodiment.

[0099] Figure 10 This is a diagram illustrating a method for manufacturing glass fiber cloth according to a third embodiment of the present technology. The manufacturing system performs warping and gluing, stretching, weaving, and thermal cleaning processes. These processes are omitted in the diagram. Details of these processes can be found, for example, in "Seizo hoho (manufacturing method)," [online], Nitto Boseki Ltd., [searched April 2, 2019], Internet (URL: https: / / www.nittobo.co.jp / business / glassfiber / about / process.htm).

[0100] As shown in the figure, after thermal cleaning, the manufacturing system performs a secondary degreasing process, using collector 311 to convey glass fibers and immerse them in a surface treatment solution tank 312 containing a silane coupling material. The manufacturing system then heats the glass fibers in a furnace 313, conveys them using collector 314, and performs further processing to complete the glass cloth. During this process, the manufacturing system can mix the heat storage material with the silane coupling material in the surface treatment solution tank 312.

[0101] Figure 11These are diagrams illustrating a method for manufacturing a mounting substrate 202 according to a third embodiment of the present technology. In the diagram, a is a diagram illustrating the manufacturing process of a varnish, and b is a diagram illustrating the manufacturing process of a prepreg material. c is a diagram illustrating the process of laminating copper foil, and d is a diagram illustrating the process of heating and pressing using a pressing machine. e is a diagram showing an example of a copper-clad laminate.

[0102] As shown in Figure a, the manufacturing system produces varnish by stirring resin, curing agent, etc., using a mixer 321, etc. In this process, in addition to resin, the manufacturing system can also mix heat storage materials.

[0103] Next, as shown in Figure b, the manufacturing system applies a varnish to the glass cloth, immerses it in an impregnation pad 322, and dries it using a heater 323. Then, the manufacturing system uses a cutter 324 to cut the glass cloth into sheets and laminates them. As a result, prepreg materials 236 and 237 are manufactured. During this process, the manufacturing system can form a heat-storing material on the surface of the prepreg material through roller coating, printing, etc.

[0104] Subsequently, as shown in Figure c, the manufacturing system stacks copper foils 271 and 272 on the two surfaces of the prepreg material.

[0105] As shown in Figure d, the manufacturing system heats and pressurizes the prepreg material, and then laminates copper foil onto the prepreg material using a pressing machine 326. As a result, a copper-clad laminate as shown in Figure e can be manufactured.

[0106] like Figure 10 and 11 As shown, prepreg materials can be manufactured by mixing heat storage materials and insulating materials. Specifically, as... Figure 10 As shown, thermal storage materials can be mixed with silane coupling materials. Furthermore, as... Figure 11 As shown in Figure a, the heat storage material can be mixed with varnish. For example... Figure 11 As shown in b, the heat storage material can also be coated onto the surface of the dry prepreg material. All three methods can be used, or only one or two can be used. Furthermore, the core material can also be manufactured using the same method as the prepreg material.

[0107] In addition, the manufacturing system mixes the thermal storage material with all core materials, prepreg materials and solder resist, but it may also mix the thermal storage material with only one or two of these materials.

[0108] Figure 12These are diagrams illustrating the process up to the formation of a via according to a third embodiment of the present technology. In the diagram, a is a diagram illustrating the process of forming a via, and in the diagram, b is a diagram illustrating the process of copper plating and forming inner layer circuitry. In the diagram, c is a diagram illustrating the process from the formation and lamination of the heat storage material to the via processing.

[0109] As shown in Figure a, the manufacturing system forms through-holes for conduction in the inner layer (core material 235) by drilling or laser processing.

[0110] Next, as shown in Figure b, the manufacturing system performs copper plating on the inner wall of the through-hole and the surface of the core material 235 to form the inner layer circuit.

[0111] Subsequently, as shown in Figure c, prepreg materials 236 and 237 are laminated, melted, and cured by hot pressing to prepare a multilayer substrate. Then, the manufacturing system forms through-holes and non-through-holes in the laminated substrate by drilling or laser processing.

[0112] The core material 235 and prepreg material 236 in the figure are obtained through... Figure 10 and 11 The material is manufactured using the method shown, and the heat storage material is mixed in.

[0113] Figure 13 This is a diagram illustrating the process prior to visual inspection in a third embodiment of the present technology. In this diagram, a is a diagram illustrating the process from desmearing to forming the outer layer circuit, and in this diagram, b is a diagram illustrating the process from forming solder resist 223 and 224 to visual inspection.

[0114] As shown in Figure a, the manufacturing system cleans the interior of the holes by performing a process of dissolving and removing unwanted deposits (drilling smudge) using plasma, chemical solutions, etc. These unwanted deposits include, for example, resin residue remaining inside the holes formed in the laminated substrate. The manufacturing system then performs copper plating on the holes formed in the laminated substrate and its outer layer, and electrically connects the copper-plated portions to the inner layer circuitry. The manufacturing system then routes signal lines 240 to the outer layer using etching or additive methods to form the outer layer circuitry.

[0115] Next, as shown in Figure b, the manufacturing system forms solder resist 223 and 224 on the front and back sides of the outer layer circuit. The manufacturing system performs gold plating on the necessary pads for purposes such as wire bonding, soldering, and forming contacts and terminals. Furthermore, if wire bonding and other purposes can be achieved, processing other than gold plating can be performed. Then, the manufacturing system performs shaping processing on the laminated substrate through router processing, shape pressing, etc., to achieve a predetermined shape. In addition, the manufacturing system electrically checks whether the necessary electrical connections of the circuits and conductive vias are performed. Finally, the manufacturing system uses an inspection machine or the like to inspect the appearance of the mounting substrate 202 according to standards to ensure it is complete.

[0116] Figure 14 This is a diagram illustrating an example composition of a solder resist according to a third embodiment of the present technology. As shown, the solder resist includes, for example, a resin, filler, color pigment, catalyst, additives, and solvent. The filler comprises approximately 20%-25% by weight. By adding microcapsules or powders of a heat storage material (e.g., paraffin or vanadium oxide) to the filler component, the solder resist ink itself can be endowed with heat storage functionality. This allows the manufacture of solder resists 223 and 224 capable of storing heat. Furthermore, the particle size of the heat storage material added to the solder resist ink is preferably 2 micrometers (μm) or smaller.

[0117] Figure 15 This is a flowchart illustrating an example of a method for manufacturing a mounting substrate 202 according to a third embodiment of the present technology. The manufacturing method of the third embodiment differs from that of the first embodiment in that the process of forming a heat storage material is not performed (steps S904 and S911). In the third embodiment, due to the use of a solder resist 223, which includes a heat storage material, the process of forming a heat storage material (step S904, etc.) can be reduced compared to the first embodiment.

[0118] As described above, in the third embodiment of this technology, a solder resist 223 including a heat storage material, a core material 235, and a prepreg material 236 are provided. Therefore, the process of providing the heat storage material becomes unnecessary when manufacturing the mounting substrate 202. This simplifies the manufacturing process of the mounting substrate 202.

[0119] Furthermore, the above embodiments illustrate examples embodying the present technology, and the matters in the embodiments and the matters specified in the claims correspond to each other. Similarly, matters specified in the claims and matters with the same names in the embodiments of the present technology correspond to each other. However, the present technology is not limited to the embodiments, and can be embodied by applying various modifications to the embodiments without departing from its spirit.

[0120] Furthermore, the effects described in this specification are merely examples and are not intended to be limiting; other effects may be achieved.

[0121] In addition, this technology can have the following configurations.

[0122] (1) A substrate comprising:

[0123] A transmission line configured to transmit a predetermined electrical signal from a semiconductor chip;

[0124] Insulating material, the transmission line being wired to the insulating material; and

[0125] A thermal storage material having a higher thermal conductivity than an insulating material and accumulating latent heat due to phase changes occurring within the operating temperature range of a semiconductor chip.

[0126] (2) The substrate described in (1) above,

[0127] The substrate includes a flexible substrate.

[0128] The transmission line is routed to the substrate, and

[0129] The base layer includes insulating material.

[0130] (3) The substrate according to (1) or (2) above,

[0131] Wherein, the substrate includes a rigid substrate, and

[0132] The transmission line is routed to the wiring layer, and a core material and a prepreg material are disposed in the wiring layer.

[0133] (4) The substrate described in (3) above,

[0134] The heat storage material is further disposed on the wiring layer, and

[0135] The core material and the prepreg material include insulating materials.

[0136] (5) The substrate according to (3) or (4) above, wherein the prepreg material includes an insulating material and a heat storage material.

[0137] (6) The substrate according to any one of (3) to (5) above, wherein the core material includes an insulating material and a heat storage material.

[0138] (7) The substrate according to any one of (3) to (6) above further includes a solder resist configured to cover the surface of the substrate.

[0139] The solder resist includes a heat storage material.

[0140] (8) An electronic device comprising:

[0141] Semiconductor chips;

[0142] A transmission line configured to transmit a predetermined electrical signal from a semiconductor chip;

[0143] Insulating material, the transmission line being wired to the insulating material; and

[0144] A thermal storage material having a higher thermal conductivity than an insulating material and accumulating latent heat due to phase changes occurring within the operating temperature range of a semiconductor chip.

[0145] (9) A method for manufacturing a substrate, the method comprising:

[0146] A heat storage material is provided, which has a higher thermal conductivity than the insulating material and is accompanied by a phase transition within the operating temperature range of the semiconductor chip; and

[0147] A wiring transmission line configured to transmit a predetermined electrical signal from a semiconductor chip to an insulating material.

[0148] (10) The method for manufacturing a substrate according to (9) above,

[0149] In the wiring, the transmission line is routed to a wiring layer, and a core material and a prepreg material are disposed in the wiring layer.

[0150] When setting the thermal storage material, the thermal storage material is further set on the wiring layer.

[0151] (11) The method for manufacturing a substrate according to (9) above further includes coating the surface of the substrate with a solder resist.

[0152] Wherein, at least one of the solder resist, the core material, and the prepreg material includes a heat storage material.

[0153] The core material and the prepreg material include insulating materials.

[0154] When setting up the heat storage material, at least one of the following is included: solder resist, core material, and prepreg material.

[0155] In wiring, transmission lines are routed to a wiring layer, in which core material and prepreg material are disposed.

[0156] [List of reference numerals]

[0157] 100 Electronic devices; 109, 240 Signal lines; 110 Semiconductor chips

[0158] 111 Solid-state imaging element 200, 201, 202 mounting substrate

[0159] 210 Digital Signal Processor 221 to 224 Solder Resist

[0160] 225 Cover Layer 230 Wiring Layer

[0161] 231, 235 core materials; 232, 233, 236, 237 prepreg materials

[0162] 251 to 259 Thermal storage materials; 271 to 274 Copper foil; 280 Base layer; 311, 314 Collectors; 312 Surface treatment solution tank.

[0163] 313 heating furnace, 321 stirrer

[0164] 322 Impregnated pad; 323 Heater; 324 Cutter; 326 Pressing machine.

Claims

1. A substrate, comprising: A transmission line configured to transmit a predetermined electrical signal from a semiconductor chip; Insulating material, the transmission line is routed on the insulating material; as well as A thermal storage material having a higher thermal conductivity than the insulating material, and the thermal storage material accumulating latent heat due to phase transitions occurring within the operating temperature range of the semiconductor chip. The transmission line is routed on the wiring layer. The heat storage material is also disposed on the wiring layer.

2. The substrate according to claim 1, in, The substrate includes a flexible substrate. The transmission line is routed to the base layer, and The base layer includes the insulating material.

3. The substrate according to claim 1, in, The substrate includes a rigid substrate, and Core material and prepreg material are provided in the wiring layer.

4. The substrate according to claim 3, The core material and the prepreg material include the insulating material.

5. The substrate according to claim 3, wherein, The prepreg material includes the insulating material and the heat storage material.

6. The substrate according to claim 3, wherein, The core material includes the insulating material and the heat storage material.

7. The substrate of claim 3, further comprising a solder resist configured to cover the surface of the substrate. in, The solder resist includes the heat storage material.

8. An electronic device comprising: Semiconductor chips; A transmission line configured to transmit a predetermined electrical signal from the semiconductor chip; Insulating material, the transmission line is routed on the insulating material; as well as A thermal storage material having a higher thermal conductivity than the insulating material, and the thermal storage material accumulating latent heat due to phase transitions occurring within the operating temperature range of the semiconductor chip. The transmission line is routed on the wiring layer. The heat storage material is also disposed on the wiring layer.

9. A method for manufacturing a substrate, the method comprising: The process of setting up a thermal storage material involves setting up a thermal storage material, wherein the thermal storage material has a higher thermal conductivity than an insulating material, and the thermal storage material is accompanied by a phase transition that occurs within the operating temperature range of the semiconductor chip. as well as In the wiring process, a transmission line is laid in the insulating material, the transmission line being configured to transmit a predetermined electrical signal from the semiconductor chip. In the wiring process, the transmission line is wired in a wiring layer, and a core material and a prepreg material are disposed in the wiring layer. In the process of setting up the thermal storage material, the thermal storage material is also set on the wiring layer.

10. The method for manufacturing a substrate according to claim 9, further comprising a coating step of coating the surface of the substrate with a solder resist. in, At least one of the solder resist, the core material, and the prepreg material includes the thermal storage material. The core material and the prepreg material include the insulating material. In the process of setting up the thermal storage material, at least one of the solder resist, the core material, and the prepreg material is provided, and In the wiring process, the transmission line is wired to the wiring layer, and the core material and the prepreg material are disposed in the wiring layer.

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