Wiring substrate
By employing a multilayer conductor and insulation layer structure in the wiring substrate, combined with materials with matching thermal expansion coefficients and a reasonable via configuration, the problem of cracks around the conductors in the vias of glass substrates was solved, achieving high reliability and miniaturization of the substrate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- IBIDEN CO LTD
- Filing Date
- 2025-11-25
- Publication Date
- 2026-06-05
AI Technical Summary
Existing wiring substrates are prone to cracking around the through-hole conductors in glass substrates, which affects the quality of the substrate.
The system employs a stacked section consisting of four or more conductor layers and four or more insulating layers, combining the connection between through-hole conductors and via conductors. It uses glass plates and insulating materials with matched thermal expansion coefficients to ensure a reasonable spacing between through-hole conductors. Through-holes are formed through laser modification and etching, and metal oxide films are used to improve the sealing.
It effectively suppresses the generation of cracks in the glass plate, improves the reliability and stability of the wiring substrate, and ensures the stable connection of electronic components and the miniaturization of the substrate's planar size.
Smart Images
Figure CN122161003A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to wiring substrates. Background Technology
[0002] Patent Document 1 discloses a wiring substrate. The wiring substrate has a glass substrate and a core substrate containing through-hole conductors that penetrate the substrate. Resin insulating layers and conductor layers are alternately laminated on both sides of the core substrate.
[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-118643
[0004] In the wiring substrate shown in Patent Document 1, it is believed that cracks sometimes occur around the through-hole conductors in the glass substrate. Summary of the Invention
[0005] The wiring substrate of the present invention includes: a core comprising a glass plate having a first side and a second side opposite to the first side; and a laminated portion formed on both sides of the glass plate, comprising stacked conductor layers and insulating layers. The laminated portion comprises four or more conductor layers and four or more insulating layers. The core includes a plurality of through-hole conductors connecting the conductor layers formed in the laminated portion on the first side to the conductor layers formed in the laminated portion on the second side. The glass plate has a thickness of 0.7 mm or more and 1.5 mm or less, and a coefficient of thermal expansion of 5 ppm / ℃ or more and 8 ppm / ℃ or less. The minimum spacing between the plurality of through-hole conductors is 100 μm or more and 200 μm or less.
[0006] According to an embodiment of the present invention, the generation of cracks in the glass plate constituting the core is suppressed, thereby improving the quality of the wiring substrate. Attached Figure Description
[0007] Figure 1 This is a cross-sectional view illustrating an example of a wiring substrate according to an embodiment of the present invention.
[0008] Figure 2 This is a top view illustrating an example of the configuration of through-hole conductors in a wiring substrate according to an embodiment.
[0009] Figure 3A This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0010] Figure 3B This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0011] Figure 3C This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0012] Figure 3DThis is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0013] Figure 3E This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0014] Figure 3F This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0015] Figure 3G This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0016] Figure 3H This is a cross-sectional view illustrating an example of the manufacturing process of a wiring board.
[0017] Label Explanation
[0018] 1: Wiring substrate; 100: Core; 100A: First surface; 100B: Second surface; 100h: Through-hole; 100G: Glass plate; 100t: Through-hole conductor; 11: First stacked layer; 111: Insulating layer of the first stacked layer; 112: Conductor layer of the first stacked layer; 12: Second stacked layer; 121: Insulating layer of the second stacked layer; 122: Conductor layer of the second stacked layer; CM: Conductor; hp: Modified layer; L: Laser; PT: Spacing between through-hole conductors; SP: Shortest distance between the outer edges of the through-hole conductors. Detailed Implementation
[0019] <Construction of the wiring substrate in the implementation method>
[0020] The wiring substrate of the embodiment will be described with reference to the accompanying drawings. Figure 1 A cross-sectional view of wiring substrate 1, as an example of a wiring substrate according to an embodiment, is shown. Furthermore, the wiring substrates illustrated in the various figures referred to in the following description are merely examples of wiring substrates according to embodiments. The layered structure of the wiring substrates of the embodiments is not limited to the layered structure of the wiring substrates shown in the figures, and the number of conductor layers and insulating layers included in the wiring substrates of the embodiments is not limited to the number of conductor layers and insulating layers included in the wiring substrates shown in the figures. In addition to the insulating layers and conductor layers present in the wiring substrates shown in the figures, the wiring substrates of the embodiments may include any number of insulating layers and conductor layers, and sometimes may not include all of the insulating layers and conductor layers present in the wiring substrates shown in the figures. Furthermore, in the various figures referred to in the following description, certain parts are sometimes depicted in enlarged detail to facilitate understanding of the disclosed embodiments. Therefore, there are cases where the structural elements of the wiring substrates of the embodiments are not depicted with respect to their size and length in precise ratios to each other.
[0021] like Figure 1As shown, the wiring substrate 1 includes a glass plate 100G and a core 100 including a plurality of through-hole conductors 100t penetrating the glass plate 100G. The glass plate 100G has a first surface 100A and a second surface 100B, which is the opposite surface of the first surface 100A. In an embodiment, the through-hole conductors 100t are mainly composed of conductors filling the through-holes 100h penetrating the glass plate 100G. The wiring substrate 1 also includes laminated portions formed on both sides of the glass plate 100G. Figure 1 In the wiring substrate 1, a first lamination portion 11 is formed on the first surface 100A of the glass plate 100G, and a second lamination portion 12 is formed on the second surface 100B.
[0022] In the wiring substrate of the embodiment, each laminated portion formed on both sides of the core 100 is composed of four or more conductor layers and four or more insulating layers. Figure 1 In the wiring substrate 1, the first stacking section 11 is composed of five insulating layers 111 and five conductive layers 112 stacked on the first surface 100A of the glass plate 100G. The insulating layers of the five insulating layers 111 and the conductive layers of the five conductive layers 112 are stacked alternately. The second stacking section 12 is composed of five insulating layers 121 and five conductive layers 122 stacked on the second surface 100B of the glass plate 100G. The insulating layers of the five insulating layers 121 and the conductive layers of the five conductive layers 122 are stacked alternately.
[0023] In addition, in the description of the wiring substrate in the embodiment, the side away from the core 100 is also referred to as "upper", "upper side", "outer side" or "outer", and the side closer to the core 100 is also referred to as "lower", "lower side", "inner side" or "inner". In addition, in each insulating layer and conductor layer, the surface facing the side opposite to the core 100 is also referred to as "upper surface", and the surface facing the core 100 side is also referred to as "lower surface".
[0024] The insulating layer 111 constituting the first stacked layer 11 includes a via conductor 113 that connects conductors formed on both sides of the insulating layer 111 in the thickness direction to each other (conductor layers 112 to each other, or conductor layer 112 to via conductor 100t). The insulating layer 121 constituting the second stacked layer 12 includes a via conductor 123 that connects conductors formed on both sides of the insulating layer 121 in the thickness direction to each other (conductor layers 122 to each other, or conductor layer 122 to via conductor 100t).
[0025] Figure 1 The adjacent through-hole conductors 100t are arranged with a configuration spacing PT. Figure 1In the example, the through-hole conductor 100t is composed of a conductor that completely fills the through-hole 100h, with the entire through-hole 100h being filled by the through-hole conductor 100t. As described later, the through-hole conductor 100t is composed of a conductor such as copper, thereby sometimes making the overall thermal expansion rate of the through-hole conductor 100t close to that of the glass plate 100G. As a result, the occurrence of defects such as cracks in the glass plate 100G is sometimes suppressed.
[0026] The through-hole conductor 100t is directly connected to the via conductor 113 and the via conductor 123. Therefore, the through-hole conductor 100t connects the conductor layer 112 constituting the first stacked portion 11 to the conductor layer 122 constituting the second stacked portion 12 via the via conductor 113 and the via conductor 123.
[0027] A solder resist layer SR1 is formed on the first laminate 11. A solder resist layer SR2 is formed on the second laminate 12. An opening SR1o is formed in the solder resist layer SR1, through which the conductor pad 112p of the outermost conductor layer 112 in the first laminate 11 is exposed. An opening SR2o is formed in the solder resist layer SR2, through which the conductor pad 122p of the outermost conductor layer 122 in the second laminate 12 is exposed.
[0028] Conductor pad 112p can be a connection pad for mounting external electronic components, etc. As shown, conductor pad 112p can be electrically and mechanically connected to connection pads of external components (IPs), such as silicon interposers, via bonding materials such as solder. Figure 1 In the example shown, components E1 and E2, which can be electronic components such as semiconductor integrated circuit devices or transistors (e.g., logic chips or memory elements), are connected to component IP. That is, electronic components that are initially mounted on the interposer can also be mounted on the wiring substrate 1. On the other hand, the conductor pad 122p can be used, for example, for connection to any substrate such as an external motherboard, electrical component, or mechanical component (not shown).
[0029] exist Figure 1 In the example shown, a reinforcing material ST is provided on the solder mask layer SR1. The reinforcing material ST is configured to avoid the area where the conductor pad 112p is provided and to surround the area where the external component IP is mounted, so as not to obstruct the mounting of the component to the surface of the wiring substrate 1. It is believed that by providing the reinforcing material ST, deformation such as bending and warping of the wiring substrate 1 can be suppressed. It is believed that by suppressing the deformation of the wiring substrate 1, the mounting of components E1 and E2 to the wiring substrate 1 is stable, ensuring good connection reliability.
[0030] The glass plate 100G constituting the core 100 is formed of glass selected from soda lime glass, aluminosilicate glass, and borosilicate glass, for example. The glass plate 100G may also contain magnesium, calcium, manganese, aluminum, lead, iron, chromium, potassium, sulfur, antimony, boron, etc., as additives. In the wiring substrate of the embodiment, the thermal expansion coefficient of the glass plate 100G is 5 ppm / °C or more and 8 ppm / °C or less. By having the glass plate 100G have a thermal expansion coefficient of 5 ppm / °C or more and 8 ppm / °C or less, it is sometimes possible to alleviate the stress caused by the difference in expansion / contraction between the first lamination portion 11 and / or the second lamination portion 12 and the glass plate 100G due to temperature changes.
[0031] The insulating layer 111 constituting the first laminate 11 and the insulating layer 121 constituting the second laminate 12 are formed using insulating resins such as epoxy resin, bismaleimide triazine resin (BT resin), or phenolic resin. Each insulating layer 111, 121 may contain reinforcing materials (core materials) such as glass fiber and / or inorganic fillers such as silica or alumina. The coefficient of thermal expansion of each insulating layer 111 and insulating layer 121 may be, for example, 15 ppm / °C or higher and 25 ppm / °C or lower, by appropriately including reinforcing materials and / or inorganic fillers, or by not including reinforcing materials and inorganic fillers. By having the insulating layers 111, 121 have a coefficient of thermal expansion of 15 ppm / °C or higher and 25 ppm / °C or lower, it is sometimes possible to reduce the stress caused by the difference in expansion / contraction between the first laminate 11 and / or the second laminate 12 and the glass plate 100G due to temperature changes.
[0032] The solder mask layers SR1 and SR2 are formed, for example, using photosensitive epoxy resin or polyimide resin. The reinforcing material ST is formed of any material capable of suppressing deformation of the wiring substrate 1. For example, any metal material such as copper alloy, aluminum alloy, or iron alloy can be used as the reinforcing material ST; as an example, high-rigidity stainless steel is used.
[0033] Conductor layers 112, 122, via conductors 113, 123, and through-hole conductors 100t can be formed using any metal such as copper or nickel. For example, conductor layers 112, 122 can be formed from metal foils such as copper foil and / or metal films formed by plating or sputtering. Conductor layers 112, 122, via conductors 113, 123, and through-hole conductors 100t in... Figure 1 For ease of observation, it is simplified to a single-layer structure, but it can have a multi-layer structure with two or more layers. Conductor layers 112, 122, via conductors 113, 123, and through-hole conductors 100t can have a two-layer structure comprising a metal film layer (e.g., electroless copper plating) and a plating film layer (e.g., electroplated copper plating). Each conductor layer 112, 122 of the wiring substrate 1 is patterned to have a prescribed conductor pattern.
[0034] exist Figure 1 In this design, the through-hole 100h, in which the through-hole conductor 100t is formed, is formed to have approximately the same inner diameter throughout the thickness of the glass plate 100G. The through-hole 100h (and the through-hole conductor 100t) may also have a shape that tapers in diameter from the first surface 100A side and the second surface 100B side toward the central portion of the thickness of the glass plate 100G. Furthermore, for convenience, the term "tightened diameter" is used, but the shapes of the through-hole 100h and the through-hole conductor 100t when viewed from above are not necessarily limited to circles. "Diameter" refers to the straight-line distance between the two furthest points on the outer edge of an object when viewed from above; "tightened diameter" means that this straight-line distance is reduced. Additionally, "viewed from above" refers to observing the object from a line of sight parallel to the thickness direction of the wiring substrate 1 (i.e., the thickness direction of the glass plate 100G).
[0035] In the wiring substrate 1, the glass plate 100G constituting the core 100 has a thickness of 0.7 mm or more and 1.5 mm or less. Glass materials such as soda lime glass, which are the main materials of the glass plate 100G, have superior rigidity compared to epoxy resin, so it is believed that even if the thickness of the glass plate 100G is as small as 0.7 mm, the wiring substrate 1 is unlikely to experience significant warping. Furthermore, it is believed that if the thickness of the glass plate 100G is 1.5 mm or less, it is easy to form through-holes 100h with a small diameter, for example, around 100 μm.
[0036] Furthermore, since the glass plate 100G constituting the core 100 has a thickness of 0.7 mm or more, warping of the wiring substrate 1 can be suppressed even though the first lamination section 11 and the second lamination section 12 are each composed of 4 or more conductor layers and 4 or more insulating layers. That is, because the first lamination section 11 and the second lamination section 12 contain a large number of conductor layers and insulating layers, even if an imbalance in the amount of expansion or contraction caused by temperature changes occurs between the two lamination sections, warping of the wiring substrate 1 is sometimes difficult to occur. Additionally, the first lamination section 11 and the second lamination section 12 may each contain conductor layers and insulating layers in numbers of 20 or fewer, preferably 15 or fewer, and more preferably 10 or fewer, respectively. By constituting each lamination section with a certain number of layers, a wiring substrate thinner than desired can sometimes be achieved.
[0037] On the other hand, glass materials, despite their excellent rigidity, have lower toughness compared to epoxy resins, which can sometimes be disadvantageous in preventing cracks caused by thermal stress around the through-holes 100h and between the through-holes 100h themselves. In this regard, in the wiring substrate 1 of the embodiment, as described above, the glass plate 100G has a coefficient of thermal expansion of 5 ppm / °C or higher and 8 ppm / °C or lower, and by appropriately configuring the through-holes 100h, i.e., by placing the through-hole conductors 100t at appropriate positions according to certain standards, crack formation is suppressed.
[0038] <Configuration of Through-Hole Conductors>
[0039] Reference Figure 2 The arrangement of through-hole conductors in the glass plate of the wiring substrate of the embodiment will be described. Figure 2 An example of a top view of the first side 100A of the glass plate 100G in the wiring substrate 1 of an embodiment is shown. For example... Figure 2 As shown, when viewed from above, a through hole 100h is formed at a specified position in the glass plate 100G, and a through-hole conductor 100t is formed in the through hole 100h. The upper surface of the through-hole conductor 100t is exposed on the first surface 100A of the glass plate 100G.
[0040] exist Figure 2 In the example shown, the glass plate 100G has a rectangular planar shape. One set of opposite sides of the rectangular planar shape has a length L1, and the other set has a length L2. In the glass plate 100G of the wiring substrate in this embodiment, both length L1 and length L2 can be 50 mm or more. The glass plate 100G has a thickness of 0.7 mm or more and a coefficient of thermal expansion of 5 ppm / ℃ or more and 8 ppm / ℃ or less. Therefore, even if the glass plate 100G is a relatively large glass plate with one side having a length of 50 mm or more, it is unlikely to develop defects such as cracks or breakage. It should be noted that the length of each side of the rectangular glass plate 100G can be 100 mm or less, preferably 85 mm or less, and more preferably 70 mm or less. If the glass plate 100G has a length of a certain value on each side, a wiring substrate smaller than the desired planar size can sometimes be achieved.
[0041] Furthermore, in the wiring substrate of the embodiment, the plurality of via conductors 100t included in the core 100 are arranged with a spacing PT of 100 μm or more. That is, the minimum spacing PT of the plurality of via conductors 100t is 100 μm or more. Therefore, two adjacent via conductors 100t are formed with a distance of at least 100 μm between their centers. In addition, the spacing PT of the plurality of via conductors 100t is the distance between (e.g., between the centers) of each of the two adjacent via conductors 100t. The "center" of each via conductor 100t is the design center position of the via 100h used in the formation of the via 100h.
[0042] In the wiring substrate of this embodiment, since the plurality of via conductors 100t are formed with a spacing PT of at least 100 μm, it is believed that sufficient resistance to deformation caused by temperature changes, etc., can be ensured between adjacent via conductors 100t. That is, it is believed that a normal state can be maintained without damage when stresses such as thermal stress are generated between adjacent via conductors 100t and around each via conductor 100t are generated. Therefore, the generation of cracks between via conductors 100t or around each via conductor 100t can be suppressed, that is, the generation of cracks between through holes 100h or around each through hole 100h can be suppressed. Therefore, according to this embodiment, the reliability of the wiring substrate is sometimes improved.
[0043] Furthermore, the minimum spacing PT between the plurality of through-hole conductors 100t is preferably 150 μm or more. If the plurality of through-hole conductors 100t are formed with a spacing PT of at least 150 μm, it is sometimes possible to further suppress the generation of cracks between the through-hole conductors 100t and around each through-hole conductor 100t.
[0044] On the other hand, the minimum spacing PT between the multiple via conductors 100t can be less than 200 μm. If the multiple via conductors 100t are formed with a spacing PT of less than 200 μm as required, miniaturization of the wiring substrate can sometimes be achieved.
[0045] It should be noted that the first side 100A and the second side 100B of glass plate 100G (refer to...) Figure 1 In the diagram, the diameter DA of the through-hole conductor 100t refers to the maximum diameter of the through-hole 100h or the through-hole conductor 100t, which can be, for example, 50 μm or more and 150 μm or less. When the through-hole conductor 100t has a diameter DA within this range, it is considered that the spacing required to ensure the resistance to force between adjacent through-hole conductors 100t is sufficient. That is, the shortest distance between the outer edges of adjacent through-hole conductors 100t (the spacing between through-hole conductors 100t) SP can be, for example, 50 μm or more and 150 μm or less.
[0046] <An example of a method for manufacturing a wiring substrate according to an embodiment>
[0047] Next, refer to Figures 3A to 3H To manufacture Figure 1 Taking the example of the wiring substrate 1, an example of a method for manufacturing the wiring substrate of this embodiment will be described. Furthermore, as long as there is no difference from the description of the materials of each structural element of the wiring substrate 1 previously provided, any of the materials previously described for each structural element can be used in the formation of each structural element.
[0048] like Figure 3AAs shown, a glass plate 100G having a first surface 100A and a second surface 100B is prepared. The thickness of the prepared glass plate 100G is 0.7 mm or more and 1.5 mm or less, and its coefficient of thermal expansion is 5 ppm / ℃ or more and 8 ppm / ℃ or less. As a glass plate 100G having a coefficient of thermal expansion within this range, for example, a plate made of glass selected from soda lime glass, aluminosilicate glass, and borosilicate glass can be prepared. Preferably, a glass plate 100G having a length of 50 mm or more in each of the two vertical directions and having a rectangular or arbitrary planar shape is prepared.
[0049] Furthermore, in the glass plate 100G, a through hole 100h is intended to be formed when viewed from above (see reference). Figure 3B Laser L is irradiated at multiple locations within a glass plate 100G. As laser L passes through the glass plate 100G, the glass structure in the areas through which laser L passes is altered in a manner highly reactive to the etching solution used in subsequent processes, compared to the glass structure in areas where laser L does not pass through. This forms a modified portion hp, consisting of the altered glass structure. The modified portion hp is formed along the thickness direction of the glass plate 100G, extending from one side of the first surface 100A and the second surface 100B of the glass plate 100G to the other. Figure 3A In the example, a columnar modified portion hp with a roughly constant diameter is formed. In the subsequent etching process, the modified portion hp is removed earlier than the surrounding unmodified portion. That is, a through-hole 100h can be formed.
[0050] As the laser L, helium-neon lasers, argon-ion lasers, excimer lasers, and various YAG lasers are used. In terms of ease of forming the modified portion hp and avoiding excessive stress on the glass plate 100G, a laser L with a wavelength of approximately 350 nm to 3000 nm is preferred. The output of the laser L is appropriately adjusted to form the modified portion hp as intended. The laser L can irradiate continuously or in pulses.
[0051] In the wiring substrate manufacturing process of the embodiment, the laser L is irradiated such that the spacing Pp between two adjacent modified portions hp in the plurality of modified portions hp is 100 μm or more. That is, in the formation of the plurality of modified portions hp, the laser L is irradiated at a distance of at least 100 μm. By irradiating the laser L in this way, it is sometimes possible to suppress the formation of cracks around the modified portions hp due to the heat generated by the irradiation of the laser L. In addition, it is believed that it is possible to suppress the through-hole 100h (see reference) caused by thermal or mechanical shock that may be applied in subsequent processes or after completion. Figure 3B The formation of cracks around ).
[0052] On the other hand, the modified parts hp can be formed such that the minimum spacing Pp between the modified parts hp is 200 μm or less. That is, the laser L can also be irradiated with a distance of only 200 μm or less between multiple modified parts hp as needed during their formation. By forming the modified parts hp with a minimum spacing of 200 μm or less, it is sometimes possible to form through-hole conductors 100t with a narrower spacing than before (see reference). Figure 3D That is, in the manufacturing process of the wiring substrate 1 in the embodiment, multiple modified parts hp can be formed with a minimum configuration spacing Pp of 100 μm or more and 200 μm or less.
[0053] As an example, an etching solution is used to remove the modified portion hp formed by irradiation with laser L. Specifically, the modified portion hp is removed by immersing a glass plate 100G with the modified portion hp formed in an etching solution, for example, an aqueous solution containing hydrogen fluoride. The concentration of the aqueous hydrogen fluoride solution is appropriately adjusted to ensure sufficient etching. Additionally, from the viewpoint of promoting etching, hydrochloric acid and / or nitric acid can be included in the etching solution, or ultrasonic waves can be propagated in the etching tank.
[0054] By removing Figure 3A HP modified part, such as Figure 3B As shown, multiple cylindrical through holes 100h are formed penetrating the glass plate 100G. Through holes 100h with arbitrary planar shapes such as circles are formed. This is achieved by removing... Figure 3A Multiple through-holes 100h formed by arranging multiple modified parts hp with a configuration spacing Pp as shown are formed with the same configuration spacing P as Pp. That is, the minimum configuration spacing P of the multiple through-holes 100h is 100 μm or more. It is believed that by forming through-holes 100h with a configuration spacing P of at least 100 μm, it is possible to suppress the generation of cracks around the through-holes 100h and / or between the through-holes 100h. For example, through-holes 100h with any diameter such as 100 μm can be formed. However, a non-zero gap is left between the through-holes 100h.
[0055] Furthermore, as mentioned above, since multiple modified parts hp are formed such that the minimum arrangement spacing Pp between the modified parts hp is 200 μm or less as required, the minimum arrangement spacing P of the multiple through holes 100h can also be 200 μm or less. Through hole conductors 100t are formed with a narrower spacing than before (see reference). Figure 3D Sometimes it is possible to manufacture wiring boards that are smaller than before.
[0056] After 100 hours of forming the through-hole, a metal oxide film (not shown) such as tin oxide or zinc oxide is preferably formed, for example, on the entire surface of the glass plate 100G and the entire surface of the inner wall exposed after 100 hours of forming the through-hole. By forming the metal oxide film, the adhesion between the glass and the metal can be improved.
[0057] like Figure 3C As shown, the interior of the through-hole 100h is filled with a conductive material CM. For example, a seed metal film made of a suitable metal such as copper or nickel is formed on the entire surface of the glass plate 100G and the entire surface of the inner wall exposed by the through-hole 100h by chemical plating or sputtering. Then, by electroplating the formed seed metal film as a power supply layer, an electroplated film made of a suitable metal such as copper is formed. The conductive material CM is formed by the seed metal film and the electroplated film. The interior of the through-hole 100h is substantially completely filled with the conductive material CM, and the first surface 100A and the second surface 100B of the glass plate 100G are covered by the conductive material CM.
[0058] The conductive material CM covering the surface of the 100G glass plate is removed, for example, by chemical mechanical polishing (CMP). Figure 3D As shown, the first surface 100A and the second surface 100B of the glass plate 100G are exposed. Additionally, within the through hole 100h, Figure 3C The conductor CM remains as a through-hole conductor 100t. Through-hole conductors 100t are obtained arranged with a minimum spacing PT of 100 μm or more, preferably 200 μm or less. The formation of the core 100, which comprises a glass plate 100G containing the through-hole conductors 100t, is completed. One end face of the through-hole conductor 100t is exposed on the first surface 100A, which is substantially flush with it, and the other end face of the through-hole conductor 100t is exposed on the second surface 100B, which is substantially flush with it.
[0059] like Figure 3EAs shown, an insulating layer 111 is formed on the first surface 100A of the glass plate 100G, and an insulating layer 121 is formed on the second surface 100B. Insulating layers 111 and 121 are formed by laminating resin films, such as epoxy resin, onto both sides of the core 100 and then hot-pressing them together. Preferably, a resin film with a thermal expansion coefficient of 15 ppm / °C or higher and 25 ppm / °C or lower is used after hot-pressing. Through-holes vh are formed at the locations where via conductors 113 or 123 are formed in insulating layers 111 and 121, for example, by irradiation with a carbon dioxide laser. Then, for example, a conductor layer 112 is formed on insulating layer 111 and a conductor layer 122 is formed on insulating layer 121 using a semi-additive method. Through-hole conductor 113 is formed in through-hole vh of insulating layer 111, and through-hole conductor 123 is formed in through-hole vh of insulating layer 121. The via conductor 113 is formed to contact the end face of the through-hole conductor 100t exposed on the first surface 100A, and the via conductor 123 is formed to contact the end face of the through-hole conductor 100t exposed on the second surface 100B.
[0060] like Figure 3F As shown, on the first surface 100A side of the glass plate 100G, four sets of insulating layers 111 and conductor layers 112 are connected through... Figure 3E The insulating layer 111 and conductor layer 112 formed in the illustrated process are formed using the same method. Through-hole conductors 113 are formed in each of the formed insulating layers 111. Conductor pads 112p are provided on the outermost conductor layer 112. As a result, a first laminated portion 11 is formed. Similarly, on the second surface 100B side of the glass plate 100G, four sets of insulating layers 121 and conductor layers 122 are further formed. Through-hole conductors 123 are formed in each of the formed insulating layers 121. Conductor pads 122p are provided on the outermost conductor layer 122. As a result, a second laminated portion 12 is formed.
[0061] like Figure 3G As shown, a solder resist layer SR1 is formed in the first stacking portion 11, and a solder resist layer SR2 is formed in the second stacking portion 12. Solder resist layers SR1 and SR2 are formed by depositing a resin film, such as a photosensitive epoxy resin or polyimide resin, using methods such as spraying or lamination. In each of the formed solder resist layers SR1 and SR2, openings SR1o and SR2o are formed, for example, by photolithography. On the surfaces of the conductor pads 112p and 122p exposed by openings SR1o and SR2o, a surface protective film (not shown) composed of Au, Ni / Au, Ni / Pd / Au, solder, or heat-resistant pre-soldering flux can also be formed by chemical plating, solder leveling, or spraying.
[0062] like Figure 3HAs shown, the reinforcing material ST is disposed on the solder mask layer SR1. The reinforcing material ST is preferably disposed in the area where the conductor pad 112p is not formed, surrounding the area where the conductor pad 112p is formed. As an example, the reinforcing material ST is formed separately from the core 100, the first laminate 11, and the second laminate 12. The reinforcing material ST is formed, for example, by machining a metal such as stainless steel into a desired shape using cutting or forming processes. As an example, the separately formed reinforcing material ST is disposed on the surface of the solder mask layer SR1 using a thermosetting resin. After the above processes, the process is completed. Figure 1 Example of a wiring substrate 1.
[0063] The wiring substrate of the embodiments is not limited to the structures illustrated in the accompanying drawings and the structures, shapes, and materials illustrated in this specification. As described above, the wiring substrate of the embodiments can have any layered structure. The wiring substrate of the embodiments can have any number of conductor layers and insulating layers. Each conductor layer can contain any conductor pattern. The core can have conductor layers on both sides of the glass plate. The through-hole penetrating the glass plate can also be filled with resin instead of being filled with through-hole conductors. It is not necessary to provide a strength-enhancing material such as ST, and electronic components can be directly mounted on the wiring substrate of the embodiments without passing through an intermediate layer.
Claims
1. A wiring substrate comprising: The core comprises a glass plate having a first side and a second side being the opposite side of the first side; and The laminated portions, formed on both sides of the glass plate, are composed of stacked conductor layers and insulating layers. in, The laminated portion consists of four or more conductor layers and four or more insulating layers. The core includes a plurality of through-hole conductors that connect the conductor layer formed in the stacked portion on the first side to the conductor layer formed in the stacked portion on the second side. The glass plate has a thickness of 0.7 mm or more and 1.5 mm or less, and a coefficient of thermal expansion of 5 ppm / ℃ or more and 8 ppm / ℃ or less. The minimum spacing between the plurality of through-hole conductors is 100 μm or more and 200 μm or less.
2. The wiring substrate according to claim 1, wherein, The glass plate has a rectangular planar shape. The length of each side of the rectangle is 50mm or more.
3. The wiring substrate according to claim 1, wherein, The thermal expansion coefficient of the insulating layer constituting the laminate portion is 15 ppm / ℃ or more and 25 ppm / ℃ or less.
4. The wiring substrate according to claim 1, wherein, The minimum spacing between the plurality of through-hole conductors is 150 μm or more.
5. The wiring substrate according to claim 1, wherein, The through-hole conductor is composed of a conductor that completely fills the through-hole penetrating the glass plate.
6. The wiring substrate according to claim 1, wherein, The shortest distance between the outer edges of the through-hole conductors is more than 50 μm and less than 150 μm.