Multilayer wiring base material substrate, multilayer wiring board, method for manufacturing multilayer wiring base material substrate and method for manufacturing multilayer wiring board

Abstract

To provide a technique which can suppress positional deviation and peeling during a manufacturing process of a multilayer wiring board.SOLUTION: One of a multilayer wiring board has a plurality of core substrates having a first surface and a second surface facing the first surface, a first wiring layer which is a wiring layer formed on the first surface, and a second wiring layer which is a wiring layer formed on the second surface, wherein the plurality of core substrates are connected to each other by a resin material filled into a gap (hereinafter referred to as "diced area") between each of the core substrate, and the adjacent core substrates among the plurality of core substrates are at least partially connected to each other by a member formed of the same material as the material of the plurality of core substrates, in the diced area.SELECTED DRAWING: Figure 23

Description

Technical Field

[0001] The present invention relates to a multilayer wiring base substrate, a multilayer wiring substrate, a method for manufacturing a multilayer wiring base substrate, and a method for manufacturing a multilayer wiring substrate.

Background Art

[0002] A multilayer wiring substrate such as an FC-BGA (Flip Chip-Ball Grid Array) substrate is an interposer substrate that electrically connects between a semiconductor device such as a processor and a printed circuit board. With the demand for higher integration of semiconductor devices, the wiring structure of multilayer wiring substrates is also progressing toward higher density.

[0003] Conventionally, as a material for wiring substrates, organic materials typified by glass epoxy resin have generally been used. In recent years, with the progress of hole drilling technology for glass materials, for example, it has become possible to form small-diameter through holes of 100 μm or less at a pitch of 150 μm or less in a 300-μm-thick glass substrate. For this reason, attention has been focused on glass as a material for electronic circuit boards. When a glass material is used for the core substrate of a multilayer wiring substrate, after pasting a glass substrate serving as a base substrate to a support, it is divided into a plurality of core substrates, and after filling and fixing a resin member between the divided substrate portions, a manufacturing method is adopted in which wiring layers and the like are formed on the plurality of core substrates using lithography processing or the like. Also, Patent Document 1 shows the following content as a multilayer substrate and a manufacturing method thereof for the purpose of providing a multilayer substrate and a manufacturing method thereof capable of realizing higher performance and higher accuracy of passive elements in a multilayer substrate incorporating passive elements. "The ceramic multilayer substrate is divided into four blocks B1, B2, B3, and B4. Block B1 has two layers of insulating layers made of AlN laminated thereon. Block B2 has two layers of insulating layers made of high-purity alumina laminated thereon, and resistor elements R1 and R2 are formed on the upper insulating layer. Block B3 is a single layer of insulating layer made of glass ceramic, and capacitor elements C1 and C2 are formed on the insulating layer. Block B4 has four layers of insulating layers made of zirconia laminated thereon. These blocks B1, B2, B3, and B4 are mechanically and electrically joined by an insulating bonding material 11 and a conductive bonding material 12 interposed between the respective blocks." In this technology, passive elements are incorporated into the multilayer substrate by forming them using printing, vacuum deposition, or the like. In addition to miniaturization, the effect of reducing high-frequency noise can also be obtained because the wiring length is shortened.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to realize a high-density wiring structure, it is necessary to maintain high processing accuracy when forming the wiring. Even in the case of a core substrate attached to a support, if misalignment occurs, the processing accuracy may decrease. Also, if the core substrate peels off from the support, the manufacturing of the multilayer wiring substrate may not be carried out, and the yield may decrease. However, in the prior art, in any case, the misalignment during dicing and the prevention of peeling between the glass substrate and the support substrate have not been sufficiently studied, and the manufacturing problems when using a glass material as the core substrate of the multilayer wiring substrate could not be solved.

[0006] Therefore, an object of the present invention is to provide a technique capable of suppressing displacement and peeling during the manufacturing process of a multilayer wiring board.

Means for Solving the Problems

[0007] In order to solve the above problems, one of the typical multilayer wiring base plates of the present invention includes a plurality of core substrates having a first surface and a second surface facing the first surface, and a first wiring layer formed on the first surface. The plurality of core substrates are connected by a resin material filled in a gap (hereinafter referred to as "fragmentation area") disposed between each of the core substrates, and at least a part of adjacent core substrates among the plurality of core substrates is connected by a member made of the same material as the core substrate.

Effects of the Invention

[0008] According to the present invention, it is possible to suppress displacement and peeling during the manufacturing process of a multilayer wiring board. Problems, configurations, and effects other than those described above will be clarified by the description in the following embodiments for implementation.

Brief Description of the Drawings

[0009]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the following description relates to an example of the present invention, and the present invention is not limited thereto. Also, in the description of the drawings, the same parts are denoted by the same reference numerals. In the drawings, the positions, sizes, shapes, ranges, etc. of the respective components shown may not represent the actual positions, sizes, shapes, ranges, etc. for the purpose of facilitating the understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0011] In the present disclosure, the term "surface" may refer not only to the surface of a plate-like member but also to the interface of a layer included in the plate-like member that is substantially parallel to the surface of the plate-like member. Further, the "upper surface" and "lower surface" mean the surfaces shown above or below in the drawing when a plate-like member or a layer included in the plate-like member is illustrated. Note that the "upper surface" and "lower surface" may also be referred to as the "first surface" and "second surface".

[0012] Also, the "side surface" means a surface or a portion of the thickness of a layer in a plate-like member or a layer included in the plate-like member. Further, a part of the surface and the side surface may be collectively referred to as an "end portion". Also, the "upper direction" means the vertically upward direction when a plate-like member or a layer is placed horizontally. Further, the "upper direction" and the opposite "lower direction" may be referred to as the "positive z-axis direction" and the "negative z-axis direction", respectively, and the horizontal direction may be referred to as the "x-axis direction" and the "y-axis direction". Also, the "bottom" may refer to a location in a direction perpendicular to the drawing plane in the drawing.

[0013] Also, the "core material" refers to the material that constitutes the base substrate. When the base substrate is a glass substrate, the core material is glass. Since the core substrate of a multilayer wiring substrate is a substrate portion separated from the base substrate, the same expression "core material" is used for the material of the core substrate of the multilayer wiring substrate.

[0014] <First Embodiment> (Regarding the step of cutting out (separating) the core substrate from the base substrate) With reference to FIGS. 1 to 8, an outline of a manufacturing process for manufacturing a core substrate of a multilayer wiring board by separating a base material substrate will be described. FIG. 1 is a diagram schematically showing a case of separating a core substrate from a base material substrate. FIG. 1(a) is a plan view of a glass substrate 60 as a base material substrate viewed from the +z-axis direction, and FIG. 1(b) is a diagram showing an enlarged part of the glass substrate 60. Although a glass substrate is used as an example of the base material substrate for explanation, the present disclosure can also be applied to a base material substrate using other materials. In an actual manufacturing process, a wiring layer is formed on the glass substrate 60, and the separation process is performed in a state of a multilayer wiring board including the core substrate. However, in the following description, the structure as a multilayer wiring layer is omitted for easy understanding.

[0015] For the glass substrate 60, a support is adhered, for example, in the -z-axis direction in order to convey the glass substrate 60 in the manufacturing process. The singulation line 64 indicated by the dashed-dotted line shows the position in the case of separating the core substrate from the glass substrate 60. Also, the laser irradiation part 65 indicates a location where a laser is irradiated inside the multilayer wiring board, and generally overlaps with the position of the through holes formed in the multilayer wiring board. As will be described later, a metal member is disposed in the through holes to form through electrodes. By irradiating the singulation line 64 and the laser irradiation part 65 with a laser to form a laser-modified part and removing the laser-modified part by etching, through holes or separation grooves are formed. FIG. 1(c) shows a case where the glass substrate is divided along the singulation line 64, and the core substrate 10 constituting the multilayer wiring board is shown as a single body.

[0016] Note that the glass substrate 60 can be composed of a transparent glass material having light transmissivity. The components of the glass, the blending ratio of each component contained in the glass, and further the manufacturing method of the glass are not particularly limited. For example, examples of the glass include non-alkali glass, alkali glass, borosilicate glass, quartz glass, sapphire glass, photosensitive glass, etc., but any glass material mainly composed of silicate may be used. Further, other so-called glass materials may be used. However, in the multilayer wiring board according to the present embodiment, it is desirable to use non-alkali glass.

[0017] For the glass substrate 60, glass manufactured by a float method, a down-draw method, a fusion method, an up-draw method, a roll-out method, etc. is used, but glass materials manufactured by any method may be used. The linear expansion coefficient of the glass is desirably in the range of -1 ppm / K or more and 15.0 ppm / K or less. The reason is that when it is -1 ppm / K or less, it is difficult to select the glass material itself. On the other hand, when it is 15.0 ppm / K or more, the difference in the thermal expansion coefficient from other layers becomes large, and there is a risk that the reliability will decrease when used in a multilayer wiring board. Further, if a silicon chip is mounted on the multilayer wiring board of the present embodiment, there is a risk that the connection reliability with the silicon chip will decrease. Note that the linear expansion coefficient of the glass is more desirably in the range of 0.5 ppm / K or more and 8.0 ppm / K or less, and even more desirably in the range of 1.0 ppm / K or more and 4.0 ppm / K or less.

[0018] (Regarding the overlap rate) Next, referring to FIG. 2, the overlap ratio of the openings will be described. FIG. 2 is a diagram for explaining the relationship between the position of the laser irradiation part and the overlap ratio of the cavity part. The overlap ratio means the ratio at which adjacent cavity parts overlap when cavity parts are formed in the glass substrate by etching the laser-modified part of the glass substrate with hydrofluoric acid. As the overlap ratio increases, the ratio at which one cavity part overlaps with adjacent cavity parts increases. FIG. 2(a) is a diagram showing the case where there are two laser irradiation parts, and FIG. 2(b) is a diagram showing the case where a plurality of laser irradiation positions are formed. Here, it will be described below assuming that the cavity part is a cylindrical hole extending in the z-axis direction.

[0019] As shown in FIG. 2(a), let the opening of the cavity formed with respect to the laser irradiation part 651 be the opening Op1, and the opening of the cavity formed with respect to the laser irradiation part 652 be the opening Op2. Let the overlapping region between the opening Op1 and the opening Op2 be DR. The overlap ratio is the size of the overlapping region DR with respect to the size of the opening Op1 or the size of the opening Op2. When creating a through hole on a substantially cylindrical shape, it is sufficient to set one laser irradiation part for one through hole. However, when using the cavity part as a separation groove (singulation line 64), a plurality of laser irradiation parts are required. As shown in FIG. 2(b), by forming laser-modified parts in a plurality of laser irradiation parts 65, adjacent openings (cavity parts) can be connected to form a separation groove in the glass substrate 60. Generally, when forming a continuous groove for dividing the glass substrate on the singulation line 64, it is desirable to make the overlapping region DR large. For example, it is desirable to set the overlap ratio to 50% or more specifically. Note that in the present disclosure, it is not limited to the case where all cavity parts are formed uniformly and continuously. A set of cavity parts formed without providing an overlapping region can be used as a separation groove, or a separation groove can be formed in a long hole shape by not overlapping a part of the cavity parts. The structure in which a part of the substrate portion serving as the core substrate is connected is also included.

[0020] (When forming continuous cavity parts) FIG. 3 is a diagram showing an example of forming a continuous cavity between two fragmentation lines 64. FIG. 3(a) is a plan view showing the positions of the fragmentation lines 64 and the laser irradiation portion 65. FIG. 3(b) is a diagram schematically showing the shape after etching of the laser modification portion, and FIG. 3(c) is a cross-sectional view taken along A-A´ (fragmentation line 64) of FIG. 3(b). In the example of FIG. 3, as shown in FIG. 3(a), the member of the glass substrate existing between the two fragmentation lines 64 is removed by etching to form a separation groove. As shown in FIG. 3(b), the cavities formed centering on the laser irradiation portion 65 overlap and connect, and the glass substrate between the two fragmentation lines 64 is removed. Therefore, the glass substrate 60 does not appear on the A-A´ plane which is the fragmentation line 64. Since the resin will be filled in the portion where the glass substrate is removed by etching in a later process, the side surfaces of the fragmented substrate portions will all be covered with resin. Therefore, in the cross-sectional view shown in FIG. 3(c), at the stage before the resin is filled, on the A-A´ plane, there is nothing present, and the cross-section of the glass substrate 60 exists in the depth direction (x-axis positive direction) of the plane.

[0021] (When forming spaced cavities) FIG. 4 is a diagram showing an example in the case where the separation grooves of the fragmentation line 64 are formed as a set of cavity portions spaced apart from each other. FIG. 4(a) is a plan view showing the fragmentation line 64 and the laser irradiation portion 65. Further, FIG. 4(b) is a diagram schematically showing the shape after etching of the laser modification portion, and FIG. 4(c) is a cross-sectional view taken along A-A'(fragmentation line 64) of FIG. 4(b). For example, in FIG. 3(b) in the case of forming continuous cavity portions, the laser modification portions are formed at a pitch W1 = 50 μm (that is, the pitch of the laser irradiation portions 65 is 50 μm), and a connected (connected) groove shape as shown in FIG. 3(b) is realized. On the other hand, in FIG. 4, under the same etching conditions, the density of the laser irradiation portions 65 is reduced to one-third, and the laser modification portions are formed in a staggered pattern. In this case, after etching, the individual cavity portions are not connected and remain as independent through holes. As a result, between the two fragmentation lines 64, a portion where the core material is removed as a cavity portion and a portion where the core material remains (core material portion 60a) are mixed. That is, by adjusting and reducing the number of the laser irradiation portions 65, as shown in the cross-sectional view of FIG. 4(c), a structure can be obtained in which the core material portion 60a remains on the side surface of the fragmented substrate portion. Note that the etching is performed from the -z-axis direction side.

[0022] Further, FIG. 5 is a diagram showing another example of the cross-sectional shape at A-A'(fragmentation line 64) shown in FIG. 4(c). FIG. 5(a) is a cross-sectional view in the case where the individual cavity portions do not overlap at all after etching. In this case, when the fragmentation line is viewed from the bottom surface (when viewed from the -z-axis direction), at all positions in the thickness direction of the glass substrate on the fragmentation line, a structure in which the core material remains partially is obtained. FIG. 5(b) is a cross-sectional view in the case where the individual cavity portions overlap only at the portions where the cavity diameter is large after etching. When the fragmentation line is viewed from the bottom surface, on the opening side surface of the glass substrate in the -z-axis direction, the etching progresses and the core member of the glass substrate does not remain, but on the surface of the glass substrate in the +z-axis direction, that is, on the bottom side of the etching, the core member remains and a structure in which the core members are partially connected even on the fragmentation line is obtained. By adjusting the position of the laser irradiation unit 65 and the etching amount, the position and size of the core material portion 60a can be adjusted. Fig. 5(a) shows a case where the pitch width is narrower and the etching amount is smaller compared to the case of Fig. 4. By continuously performing etching from the state shown in Fig. 5(a), as shown in Fig. 5(b), the core material portion 60a can be processed to be smaller. In this case, no core material remains on the opening side (z-axis minus side) of the glass substrate, but only the core material remains on the bottom side (z-axis plus side).

[0023] (Function and effect by leaving the material of the glass substrate in the separation groove) In the manufacturing process of the multilayer wiring board, after forming the separation groove, the separation groove is filled with resin, and the subsequent processes are advanced. Therefore, the cross-sectional structure of the singulation line has various states from a state where all is covered with resin (Fig. 3(c)) to a state where all the core material is exposed. When the area of the exposed core material is small, the remaining area is filled with resin or the like, so the resin material can relieve the stress (caused by the difference in thermal expansion coefficient, thermal shrinkage, etc.) associated with the formation of the wiring and the insulating layer of the multilayer wiring, and it is possible to suppress cracking (fracture) of the core substrate. On the other hand, when all is covered with the resin material, the individual substrate portions are not connected by the core material to the adjacent substrate portions, and the core materials constituting the individual substrate portions become isolated. Therefore, when etching the glass substrate in a state where the substrate portions are separated, problems such as the substrate portions being easily peeled off (detached) from the support or being easily displaced occur. Thus, it is important to leave the core material of the glass substrate to such an extent that it is connected (connected) to the adjacent substrate portions while removing most of it from the singulation line to facilitate the dicing process.

[0024] (Side protection rate) Here, the ratio of the core material of the substrate portion covered on the side wall of the substrate portion to be fragmented is called the side wall protection rate. In other words, the side wall protection rate is the ratio of the area where the side surface of the diced substrate portion (multilayer wiring substrate) is covered by resin or metal in the cross section of the substrate portion.

[0025] Specifically, as shown in FIG. 1(c), the core substrate 10 fragmented has a cross section with four sides diced, and the side surface protection rate is the average value of the ratios of the protected areas in the four cross sections. For example, in the substrate portion with the A-A' cross section in FIG. 3(c) regarded as four side surfaces, since the side surfaces are completely covered by the resin or metal member filled in the separation groove, the side wall protection rate is 100%. On the other hand, in the substrate portion with the A-A' cross section in FIG. 4(c) regarded as four side surfaces, the side wall protection rate is about 40%.

[0026] From the perspective of suppressing misalignment and peeling, the side wall protection rate is preferably 30% or more and 99% or less, and more preferably 60% or more and 95% or less. When the side wall protection ratio exceeds 99%, there are too few connection parts in the base substrate before dicing, and it becomes difficult to obtain the effect of suppressing misalignment. On the other hand, when it is less than 30%, the exposed ratio of the core material of the glass substrate becomes excessively large, cracks caused by stress are likely to occur in the substrate portion, and the generated cracks are connected to each other, leading to large-scale cracks and splits. In contrast, when the side wall protection ratio is 60% or more and 95% or less, it is possible to balance the effect of suppressing misalignment by being connected before dicing and the effect of suppressing cracks at the ends. Also, although details will be described later, as shown in FIGS. 7(c) and 7(e), when the core material portion 60a is formed in a shape where some of the substrate portions are connected (if possible, connected at one location for each substrate), there are no isolated substrate portions and it becomes difficult to misalign.

[0027] (Example of the shape of the fragmentation line (separation groove)) FIG. 6 schematically shows variations when the appearance of the fragmentation line is viewed in a plan view. The opening shape at the opening Ob in the negative z-axis direction of the cavity is shown by a solid line, and the opening shape at the opening Ot in the positive z-axis direction of the cavity is shown by a hatched shape. Also, the laser irradiation part 65 is shown by black dots, and the fragmentation line 64 is shown by a dashed line.

[0028] FIG. 6(a) shows a case where the area of the fragmentation line 64 (hereinafter, also referred to as the "fragmentation area") is formed by repeating the cavity part. The fragmentation area refers to a cavity part in the glass substrate 60 from which the glass member has been removed. The laser irradiation parts 65 are set at equal intervals, and a region where no glass substrate exists is formed on the fragmentation line 64. The openings Ot exist independently, while the openings Ob are connected. When viewed in a cross-section in the z-axis direction, the core material part 60a also exists partially in the fragmentation line, and the individual glass substrates are partially connected to each other.

[0029] Also, FIG. 6(b) shows a case where the fragmentation area is formed by repeating the long holes. Three laser irradiation parts 65 are arranged close to each other, and both the opening Ob and the opening Ot are connected on the fragmentation line to form a long-hole-shaped cavity part. For the three long-hole shapes, the opening Ob on the negative z-axis side is connected, but the opening Ot on the positive z-axis direction is not connected. When viewed in a cross-section in the z-axis direction, in the z-axis direction, regions where the glass substrate exists and regions where it does not exist alternate on one fragmentation line.

[0030] Also, FIG. 6(c) basically forms the fragmentation area as a continuous area, but leaves the core material part 60a of the glass substrate 60 at a part of the intersection of the fragmentation lines. The continuous area can also be an aggregate of cavity parts and long holes. The laser irradiation parts are arranged on two fragmentation lines 64 and between the two fragmentation lines, and both the opening Ot and the opening Ob are continuous. FIG. 6(c) shows a case where two fragmentation lines intersect, and no laser irradiation part 65 is formed in the region where the fragmentation lines intersect, and the glass substrate is left without being etched.

[0031] Also, FIG. 6(d) shows another example of the repetition of the cavity portion. The laser irradiation portions 65 are alternately arranged between and at both ends of the two singulation lines 64 in the y-axis direction. The opening Ob and the opening Ot are not connected to other openings.

[0032] In this way, by combining laser modification and etching, it is possible to form the shapes of various singulation lines (separation grooves, singulation areas). It is also possible to appropriately combine and select any of the structures or composite structures shown in FIGS. 5 and 6.

[0033] Also, FIG. 7 shows a schematic diagram of variations of the singulation area in FIG. 6. Generally, the cavity portion forming the singulation area has a smaller opening diameter as it goes from the negative z-axis direction to the positive z-axis direction. For this reason, the core material portions 60a are also distributed along the z-axis and in each xy plane. FIG. 7(a) shows the repetition of unconnected holes, FIG. 7(b) shows the repetition of slots, FIG. 7(c) shows the case where a part of the core material portion 60a remains at the intersection, and FIG. 7(e) shows the case where a part of the core material portion 60a remains at the intersection of the sides of each piece or the singulation line.

[0034] As shown in FIG. 7, by leaving a part of the core material of the singulation line, after etching the core material, the individual pieces do not detach and proceed to the next process while remaining as a single substrate. As a result, in subsequent processes, it becomes difficult for positional displacement of some pieces, peeling from the underlying layer, etc. to occur.

[0035] (Formation position of core material portion) Next, with reference to FIG. 8, the formation position of the core material portion 60a, that is, the frequency (number) of joining portions will be described. The core material portion 60a is arranged at the upper, lower, left, and right (positions of the four sides of the singulation line) and diagonally (upper left, upper right, lower left, lower right) (intersections of the singulation lines) in the substrate portion to be singulated, and it is desirable that at least one joining portion exists between adjacent substrate portions. If there are too many joining portions, when singulating, the possibility of crack propagation increases. FIG. 8 is a diagram schematically showing the arrangement locations of the core material portions 60a. The portions surrounded by the dashed circles indicate the core material portions 60a. For example, FIG. 8(a) shows the case where the center of the side of the singulated substrate is the core material portion 60a, and FIG. 8(b) shows the case where the corner portion of the singulated substrate is the core material portion 60a. Also, FIG. 8(c) shows the case where the corner portion of the singulated substrate is the core material portion 60a, but with fewer core material portions 60a than in FIG. 8(b) (two locations in each singulated substrate). When reducing the core material portion 60a, it becomes less likely for cracks to occur in the core substrate 10, but misalignment is more likely to occur. Therefore, it is desirable to adjust the sidewall protection ratio and the number of joining portions of the core material portion 60a according to the material and thickness of the core substrate 10.

[0036] In the case of FIG. 8, in FIG. 8(a), the core material portion 60a is at the center of the side, and in FIGS. 8(b) and 8(c), the core material portion 60a is arranged at the corner of the core substrate 10. When there is only the core material portion 60a at the corner, during dicing, the corner is likely to be chipped and the outer shape is likely to become unstable. However, in the case of the corner, even if cracks or chips occur, the impact on the wiring etc. in the central area of the substrate is small. On the other hand, when forming the core material portion 60a near the center of the side, chipping and cracking are less likely to occur than at the corner, but the impact when they occur is large. The location, number, width, etc. of the core material portion can be appropriately changed considering the ease of cracking associated with the material and thickness of the core substrate, and the ease of misalignment associated with the adhesion between the underlying adhesive layer as the support and the core substrate.

[0037] <The first manufacturing method according to the embodiment of the present invention> Next, with reference to FIGS. 9 to 24, a method for manufacturing a multilayer wiring board to which the above-described core material portion is applied will be described.

[0038] (Adhesion of the first support) First, with reference to FIG. 9, a step of adhering a first support 61 to a glass substrate 60 which is a base substrate will be described. FIG. 9 is a cross-sectional view for explaining the adhesion step of the first support 61 in the manufacturing method according to the first embodiment. The glass substrate 60 has a first surface 20 and a second surface 30. As shown here, using a first adhesive layer 62, the first support 61 is bonded to the glass substrate 60 to form a laminated structure 63 composed of the glass substrate 60, the first adhesive layer 62, and the first support 61. Since the first adhesive layer is extremely thin compared to the glass substrate 60 and the first support 61, the first adhesive layer can also be described as an interface between the glass substrate 60 and the first support 61. However, in the drawings of the present disclosure, for clarity, it is illustrated as a layer having a thickness. Also, while the glass substrate 60 extends in the y-axis direction, a part thereof is excerpted and shown in the drawing, and thus the ends in the y-axis direction are shown as straight lines.

[0039] The first adhesive layer 62 is an adhesive layer for temporarily fixing the first support 61 to the glass substrate 60. The first adhesive layer 62 is a surface containing a hydroxyl group formed on the second surface 30 of the glass substrate 60. The configuration of the adhesion interface may contain a plurality of other functional groups as long as it contains a hydroxyl group. Therefore, the material of the first adhesive layer 62 can be appropriately selected from resins that can be peeled off by absorbing light such as UV light and generating heat, sublimating, or changing in quality, resins that can be peeled off by foaming due to heat, or functional groups, etc. In order to bond the first support 61 to the glass substrate 60, for example, a laminator, a vacuum pressure press, a vacuum bonding machine, or the like can be used. Thus, by forming an interface containing a hydroxyl group on the second surface 30 of the glass substrate 60, it becomes possible to form a hydrogen bond using the hydroxyl group between the glass substrate 60 and the first support 61. Note that the adhesive layer containing a hydroxyl group can also be formed on the first surface 20 of the glass substrate 60.

[0040] The first support 61 is preferably made of the same material as the glass substrate 60. When the material of the glass substrate 60 is non-alkali glass, the material of the first support 61 is also preferably non-alkali glass. Also, the thickness of the first support 61 can be appropriately set according to the thickness T1 of the glass substrate 60. However, it is preferably a thickness that can be transported during the manufacturing process. For example, the thickness T1 of the glass substrate 60 is in the range of 75 μm or more and 200 μm or less, and the thickness of the first support 61 can be set in the range of 300 μm or more and 1,500 μm or less.

[0041] In this embodiment, the first support 61 is made of a glass material, and a hydroxyl group (hydroxyl group) and a plurality of functional groups are used as the adhesive interface.

[0042] The adhesion strength between the glass substrate 60 and the first support 61 is 0.15 J / cm 2 or more and 0.45 J / cm 2 or less. If the strength in the above range cannot be obtained, an annealing treatment may be performed after forming the hydroxyl group to improve the adhesion strength. When the adhesion strength is 0.15 J / cm 2 or less, there is a high possibility of peeling at the interface between the glass substrate 60 and the first support 61 during the process flow. Conversely, when the adhesion strength is 0.45 J / cm 2 or more, problems are likely to occur in the peeling process described separately for the adhesion strength. More preferably, it is in the range of 0.25 J / cm 2 or more and 0.4 J / cm 2 or less. Note that the adhesion strength was measured using the crack opening method, but the measurement method is not limited to this.

[0043] (Formation of Laser Modification Portion) Next, with reference to FIG. 10, the formation process of the laser modification portion will be described. FIG. 10 is a cross-sectional view for explaining the formation process of the laser modification portion in the manufacturing method according to the first embodiment. In FIG. 10, the broken line indicates the laser modification portion 65a. As shown in FIG. 10, the laminated structure 63 is irradiated with a laser from the first surface 20 side to form the laser modification portion 65a. The laser modification portion 65a extends, for example, in a direction perpendicular to the glass substrate 60 and can be formed at a desired position over substantially the entire surface of the glass substrate 60. At this time, the laser modification portion 65a may be formed so as to reach the first adhesive layer 62 and the first support 61. Note that the position on the first surface 20 where the laser is irradiated is the laser irradiation portion 65, and on the glass substrate 60, the laser modification portion 65a is formed in the z-axis direction from the laser irradiation portion 65.

[0044] In the present embodiment, by irradiating the laser with the first support 61 stacked on the glass substrate 60, it is possible to widen the processing conditions (process window) of the laser irradiation, and it is possible to form the laser modification portion 65a at a desired position with respect to the glass substrate 60. Further, the laser may be irradiated from the second surface side of the laminated structure 63, or the glass substrate 60 alone may be irradiated.

[0045] Here, when an adhesive layer made of resin is used as the first adhesive layer 62, cracks may occur in the resin of the adhesive due to laser irradiation, and an event may occur in which the adhesive resin remains on the glass substrate 60 when the first support 61 is peeled off from the glass substrate 60. When such an adhesive resin remains on the glass substrate 60, it may cause problems in the subsequent through-hole formation process by hydrofluoric acid etching. For example, it may lead to the occurrence of surface irregularities on the glass substrate 60. Therefore, for the adhesion between the glass substrate 60 and the first support 61, it is desirable to use an interface containing a hydroxyl group rather than a resin adhesive layer.

[0046] (Formation of the first wiring layer) Next, referring to FIG. 11, the formation process of the first wiring layer 21 will be described. FIG. 11 is a cross-sectional view for explaining the formation process of the first wiring layer in the manufacturing method according to the first embodiment. As shown here, a first wiring layer 21 including a conductive layer and an insulating layer is formed on the first surface 20 of the glass substrate 60 of the laminated structure 63. First, a seed layer including a hydrofluoric acid-resistant metal layer 15 is formed on the glass substrate 60. The hydrofluoric acid-resistant metal layer 15 on the glass substrate 60 is an alloy layer containing at least one of chromium or nickel, and is formed by sputtering in the range of 10 nm or more and 1,000 nm or less. Then, a conductive metal film is formed on the hydrofluoric acid-resistant metal layer 15 with a desired thickness. As the material of the conductive metal film, for example, it can be appropriately set from Cu, Ni, Al, Ti, Cr, Mo, W, Ta, Au, Ir, Ru, Pd, Pt, AlSi, AlSiCu, AlCu, NiFe, ITO, IZO, AZO, ZnO, PZT, TiN, Cu3N4. The formation of the electrode connection part (electrode) and the wiring can be performed, for example, by a semi-additive (SAP) method. In the semi-additive method, a photoresist is used to form a desired pattern. Generally, a dry film resist is used, but a liquid resist may also be used. After exposing and developing the resist to form a desired pattern, an electroplated film with a thickness of 2 μm or more and 20 μm or less is formed by electrolytic plating. The unnecessary resist pattern is peeled off, and the seed layer is etched to form a through electrode connection part 41 located above the laser modification part and a wiring 16 located between the laser modification part 65a.

[0047] The formation of the dielectric layer 14 on the through electrode connection portion 41 is performed using at least one of alumina, silica, silicon nitride, tantalum oxide, titanium oxide, calcium titanate, barium titanate, and strontium titanate from the viewpoints of insulation and relative permittivity. The thickness of the dielectric layer 14 is desirably in the range of 10 nm or more and 5 μm or less. When the thickness of the dielectric layer 14 is 10 nm or less, it may not be possible to maintain insulation and the function as a capacitor may not be exhibited. When the thickness of the dielectric layer 14 is 5 μm or more, not only does the film formation time become too long and lack mass productivity, but there is also a possibility that it will take more time in the process of removing unnecessary portions. For this reason, the thickness of the dielectric layer 14 is more desirably in the range of 50 nm or more and 1 μm or less.

[0048] The capacitor electrode 13 is formed by dividing it into a lower electrode layer and an upper electrode layer. As the lower electrode layer, from the viewpoints of adhesion and electrical conductivity, it can be formed using at least one of Cu, Ni, Al, Cr, Mo, W, Ta, Au, Ir, Ru, Pd, Pt, AlSi, AlSiCu, AlCu, NiFe, and Cu as a material. For example, Ti is excellent in terms of adhesion, electrical conductivity, ease of manufacturing, and cost.

[0049] A seed metal layer is formed on the upper electrode of the capacitor electrode 13, and further an electrolytic plating layer is formed. As the seed metal layer, for example, at least one of Cu, Ni, Al, Ti, Cr, Mo, W, Ta, Au, Ir, Ru, Pd, Pt, AlSi, AlSiCu, AlCu, NiFe, and Cu can be applied. From the viewpoint of facilitating subsequent etching removal, it is desirable to use copper. The thickness of the seed metal layer is desirably in the range of 10 nm or more and 5 μm or less. When the thickness of the seed metal layer is less than 100 nm, there is a possibility of poor electrical conduction occurring in the subsequent electrolytic plating process. When the thickness of the seed metal layer exceeds 5 μm, it will take time for etching removal. For this reason, the thickness of the seed metal layer 113 is more desirably in the range of 100 nm or more and 500 nm or less.

[0050] Thereafter, an electrolytic plating layer is formed as the upper electrode of the capacitor electrode 13. Electrolytic copper plating is simple, inexpensive, and has good electrical conductivity. In addition to electrolytic copper plating, electrolytic nickel plating, electrolytic chromium plating, electrolytic Pd plating, electrolytic gold plating, electrolytic rhodium plating, electrolytic iridium plating, etc. may also be used. After the upper electrode is formed, the seed metal layer is removed. As the removal method, it can be appropriately set according to the application, such as wet etching, dry etching, etc.

[0051] Regarding the formation of the capacitor electrode 13, in the conventional manufacturing method of manufacturing a multilayer wiring board using a substrate on which the through hole 11 is previously formed, since a conductive material cannot be deposited on the through hole, it is necessary to form a MIM structure avoiding the through hole. On the other hand, according to the manufacturing method according to this embodiment, since the wiring formation step and the capacitor electrode formation step are performed before the through hole formation step, the capacitor electrode 13 can be formed near the through hole and above the through hole, in other words, without being restricted by the position of the through hole. For example, it is also possible to provide the capacitor electrode 13 directly above the through hole. By this, the transmission distance to the capacitor can be shortened, and the deterioration of the transmission characteristics can be avoided. Furthermore, by forming the lower electrode layer when forming the capacitor electrode 13, it becomes possible to reduce the variation in the capacitor capacitance.

[0052] Finally, the insulating resin layer 25 is formed. The insulating resin layer 25 is composed of a thermosetting resin, and its material includes at least one of epoxy-based resins, polyimide-based resins, and polyamide-based resins, includes a filler material of SiO2, and is preferably a liquid or film-like material. In the case of a liquid resin, the insulating layer can be formed by spin coating, and in the case of a film-like resin, heating and pressing can be performed under vacuum using a vacuum laminator. The material of the insulating resin layer 25 can be appropriately selected as needed. However, when using a photosensitive insulating resin material, it is difficult to fill the filler material of SiO2 to ensure photolithography properties, so it is limited to a non-photosensitive thermosetting resin.

[0053] Regarding the characteristics of the insulating resin layer 25 in detail, the insulating resin layer 25 has a relative permittivity in the range of 3.1 or more and 3.5 or less, and a dielectric tangent in the range of 0.002 or more and 0.012 or less. The insulating resin layer 25 is formed of a thermosetting resin. Examples of the thermosetting resin include epoxy resins, polyimide resins, polyamide resins, and composite materials thereof, and those filled with a filler material containing at least SiO2 in the range of 65% or more and 80% or less are used. When the filling rate of the filler material of SiO2 is 65% or less, the relative permittivity and the dielectric tangent are out of the above range, which causes a decrease in transmission characteristics. More preferably, the filling rate of the filler material of SiO2 is 72% or more. Among the above composite materials, a material with a high filling rate of the filler material of SiO2 has a low coefficient of linear expansion of the insulating resin and a value close to that of the glass material. Therefore, by using such a material, it is possible to reduce the stress that may occur when the wiring layer is formed on the core substrate 10. By doing so, the values of the relative permittivity and the dielectric tangent can be suppressed within the above range, and it is possible to avoid affecting the transmission characteristics.

[0054] (Adhesion of the second support) Next, with reference to FIG. 12, the adhesion process of the second support will be described. FIG. 12 is a cross-sectional view for explaining the adhesion process of the second support in the manufacturing method according to the first embodiment. As shown here, a second adhesive layer 71 can be formed on the first wiring layer 21 of the laminated structure 63, and the second support 70 can be adhered to the second adhesive layer 71.

[0055] Regarding the second adhesive layer 71, similar to the first adhesive layer 62, a resin that can be peeled off by absorbing light such as UV light and generating heat, sublimating, or changing in quality, a resin that can be peeled off by foaming due to heat, or a functional group that temporarily fixes the glass substrate 60 and the first support 61 can be appropriately selected. However, it is preferably formed of a material different from that of the first adhesive layer 62.

[0056] Regarding the second support 70, it is preferably made of the same material as the glass substrate 60. When the glass substrate 60 is alkali-free glass, it is desirable that the first support 61 is also alkali-free glass. Also, the thickness of the second support can be appropriately set according to the thickness of the glass substrate 60. However, it is preferably a thickness that can be transported, and it is desirable to be in the range of 300 μm or more and 1,500 μm or less.

[0057] (Peeling of the first support) Next, with reference to FIG. 13, the peeling process of the first support will be described. FIG. 13 is a cross-sectional view for explaining the peeling process of the first support 61 in the manufacturing method according to the first embodiment. As shown here, the interface between the glass substrate 60 and the first adhesive layer 62 can be peeled, and the first adhesive layer 62 and the first support 61 can be separated from the glass substrate 60.

[0058] When separating the first support 61 from the glass substrate 60, a physical force is applied to the side surface of the first adhesive layer 62 to form a peeling start portion, and by applying a force starting from this peeling start portion, the interface of the first adhesive layer 62 can be peeled. More specifically, the portion where the side surface of the first adhesive layer 62 is scratched with a cutter or the like is used as the peeling start portion, and by applying a force in the direction of pulling the first support 61 and the glass substrate apart, the glass substrate 60 and the first support 61 can be separated. In addition, when a scratching process is performed while applying a force to pull the first support 61 and the glass substrate apart, the peeling process can be performed smoothly. Depending on the material used for the first adhesive layer 62, a peeling method according to the used material, such as UV light irradiation, heat treatment, physical peeling, etc., will be appropriately selected. Also, when a residue of the first adhesive layer 62 remains on the glass substrate 60, plasma cleaning, ultrasonic cleaning, water cleaning, solvent cleaning using alcohol, etc. may be performed.

[0059] (Formation of through holes by etching) Next, with reference to FIGS. 14 to 16, the process of forming through holes by etching will be described. FIG. 14 is a cross-sectional view for explaining the process of forming through holes by etching in the manufacturing method according to the first embodiment. FIG. 15 is a bottom view (viewed from the negative z-axis direction) when a separation groove is formed. FIG. 14 shows the shape of the glass substrate 60 after hydrofluoric acid etching. Specifically, it shows the cross-section taken along line A-A' in FIG. 15. Through holes 11 and separation grooves 17 are formed by hydrofluoric acid etching. The through holes 11 are the locations where through electrodes 12 to be described later are formed, and are formed at the positions of the through electrode connection portions 41. The separation grooves 17 are cavity portions that become singulation areas, and have a structure in which the insulating resin layer 25 is exposed. The core material portion 60a is a location where no separation groove 17 is formed and the core material exists. Note that the sizes of the separation grooves 17 and the through holes 11 are shown with modified sizes in FIGS. 14 and 15 for ease of understanding.

[0060] As a specific etching method, first, as shown in FIG. 14, the laser modified portion 65a is selectively removed by etching from the second surface 30 side of the glass substrate 60. Thereby, through holes 11 and separation grooves 17 are formed. Wet etching using an aqueous hydrofluoric acid solution is suitable for the etching. The etching amount by the aqueous hydrofluoric acid solution is appropriately set according to the thickness of the glass multilayer wiring substrate. For example, when the thickness T1 of the glass substrate 60 is 200 μm, it is desirable that the etching amount be in the range of 50 μm or more and 175 μm or less. Note that although a structure in which the insulating resin layer 25 is exposed is shown here, the structure is not limited thereto. When a seed layer including the hydrofluoric acid resistant metal layer 15 of the first wiring layer 21 remains in the separation groove 17, the seed layer of the first wiring layer 21 may remain in the singulation line portion (separation groove 17).

[0061] Incidentally, along with the etching of the laser modification portion 65a, the glass substrate 60 is also etched in the same manner. The thickness T2 of the glass substrate 60 after etching is desirably in the range of 25 μm or more and 150 μm or less. Here, in a conventional multilayer wiring board, the thickness of the core substrate was generally 300 μm or more and 400 μm or less. In the first embodiment, since a thin core substrate can be realized, the influence on transmission characteristics can be suppressed. Note that the second surface 30 in FIG. 14 is the surface after etching, and thus is not the same as the surface before etching, but is denoted as the second surface 30 for ease of understanding.

[0062] Also, the width M1 of the separation groove 17 is preferably 100 μm to 500 μm. Generally, since the thickness of a dicing saw is several tens of μm, the processing groove during dicing is the same as the width of the dicing saw but is about several μm wider. In contrast, in consideration of the positioning accuracy of the dicing saw, it is desirable to set the processing groove so as not to affect the core material. If the width of the processing groove is 100 μm or less, the positioning accuracy tends to be strict when the above is considered. For example, when the core material shrinks due to a heat history or the like, the actual processing position may deviate from the designed processing position. On the other hand, when the width M1 of the groove is set to 500 μm or more, the extra area within the base substrate becomes large, the area efficiency decreases, and this becomes a factor for cost increase.

[0063] As shown in FIG. 15, in the present disclosure, since the substrate portions after singulation are connected in part, displacement on the second adhesive layer 71 hardly occurs, and peeling from the second adhesive layer 71 and detachment of the individual pieces can be suppressed.

[0064] FIG. 16 is a diagram showing an enlarged view of the region R1 in FIG. 15. At the bottom of the separation groove 17, Cr and Cu are deposited at the bottom after hydrofluoric acid etching, and a transfer trace 65T of the laser modification portion 65a is formed in the insulating resin layer, and minute irregularities are formed. Regarding the above irregularities, when wiring is formed thereafter and the insulating resin of the second wiring layer is formed, an anchor effect is produced, and the adhesion between the insulating resin layer 25 and the glass substrate 60 can be improved.

[0065] (Formation of the Second Wiring Layer) Next, with reference to FIG. 17, the process of forming the second wiring layer will be described. FIG. 17 is a cross-sectional view for explaining the process of forming the second wiring layer in the manufacturing method according to the first embodiment. As shown here, a second wiring layer 22 composed of a through electrode connection portion 42 and an insulating resin layer 25 is formed on the second surface 30 of the glass substrate 60. For forming the through electrode 12 and the through electrode connection portion 42, formation of a power supply seed layer, pattern formation with a resist, and plating treatment are performed so as to form a plating with a thickness of 2 μm or more and 20 μm or less. Thereafter, the unnecessary resist pattern is peeled off, the seed layer is removed, and the through electrode 12 and the through electrode connection portion 42 are formed. Finally, the insulating resin layer 25 is formed, and the second wiring layer 22 is formed. The insulating resin layer 25 is also filled in the through electrode 12. In the example shown here, it is assumed that the insulating resin layers 25 formed in the first wiring layer 21 and the second wiring layer 22 are made of the same material, but it is not limited thereto. The insulating resin layer may be formed of different materials.

[0066] In the second wiring layer 22, since there is no etching treatment with a hydrofluoric acid aqueous solution in the subsequent process, a material different from the hydrofluoric acid resistant metal layer 15 can be used. In this case, a metal layer made of a material different from the hydrofluoric acid resistant metal layer 15 is formed on the side surface of the through hole 11, and the through electrode connection portion 42 is formed. Examples of the material different from the hydrofluoric acid resistant metal layer 15 include Ti, Cu, etc., and at least one or more metal layers made of these materials are formed on the side surface of the through hole 11 and on the second surface 30 of the glass substrate 60. The material, the number of layers, etc. are not limited only to the disclosed content of the embodiment, and can be appropriately set as necessary.

[0067] When forming the above-mentioned insulating resin layer 25, the resin material is also filled into the singulation lines (separation grooves) at the same time. By filling the singulation lines with resin or the like, it is possible to suppress the core material from cracking during singulation by dicing or the like. In a multilayer wiring board, it is possible to obtain insulation for each layer with an interlayer insulating resin and at the same time protect the ends of the core material. However, it is also possible to form a pattern by dispensing resin or paste separately into the singulation lines, forming a metal film, or applying and exposing a photosensitive resin containing inorganic substances such as fillers.

[0068] From the viewpoint of stress relaxation during singulation, substances filled into the singulation lines are preferably resins or the like with a low elastic modulus. When the core material is a brittle material such as glass, cracks are likely to occur during dicing, and these cracks may progress and lead to breakage, chipping, or splitting. In the present invention, breakage of the core material is suppressed by filling the dicing lines with crack-resistant materials such as resins and metals as described above.

[0069] (Peeling of the second support) Next, with reference to FIGS. 18 and 19, the peeling process of the second support 70 will be described. FIG. 18 is a diagram for explaining the peeling process of the second support 70 in the manufacturing method according to the first embodiment. FIG. 19 is a diagram showing the state after the peeling process of the second support 70 is performed in the manufacturing method according to the embodiment of the present invention. As shown in FIG. 18, the interface between the first wiring layer 21 and the second support 70 is peeled, and the second support 70 and the second adhesive layer 71 are separated. As a result, as shown in FIG. 19, a glass substrate 60 is obtained in which the first wiring layer 21 is formed on the first surface 20 side of the glass substrate 60 and the second wiring layer 22 is formed on the second surface 30 side. When separating the second support 70 from the second wiring layer 22, the peeling method such as UV light irradiation, heat treatment, or physical peeling can be selected according to the material used as the second adhesive layer 71. Also, when a residue of the second adhesive layer 71 remains on the bonding surface between the first wiring layer 21 and the second adhesive layer 71, plasma cleaning, ultrasonic cleaning, water cleaning, solvent cleaning using alcohol, or the like may be performed.

[0070] (Formation of Build-up Layers) Next, with reference to FIG. 20, the formation process of a build-up layer, that is, a layer formed by laminating a first wiring layer 21 and a second wiring layer 22, will be described. FIG. 20 is a diagram for explaining the formation process of the build-up layer in the manufacturing method according to the first embodiment. As shown in FIG. 20, a conduction electrode 31 for connecting the first wiring layer on the first surface side and a conduction electrode 32 for connecting the second wiring layer on the second surface side are formed on the first wiring layer 21 on the first surface 20 side and the second wiring layer 22 on the second surface 30 side of the glass substrate 60. The conduction electrodes 31 and 32 can be formed by forming vias in the insulating resin layer 25 with a laser, then forming a seed layer on the vias, and then using a semi-additive process (that is, performing a series of processes of resist pattern formation, plating, resist stripping, seed layer removal, and insulating resin layer formation). Note that at least one or more layers of the first wiring layer 21 and the second wiring layer 22 are laminated, and the appropriate number of layers can be set as needed. In FIG. 20, two layers of both the first wiring layer 21 and the second wiring layer 22 are laminated.

[0071] The laser used to form the conduction electrodes 31 and 32 can be a laser different from the laser used to form the laser modified portion 65a. For example, it is desirable to use a pulsed laser such as a carbon dioxide laser or a UV-YAG laser, and a laser with a pulse width on the order of μs is suitable.

[0072] (Formation of Connection Pads) Next, with reference to FIG. 21, the formation of connection pads will be described. FIG. 21 is a diagram for explaining the process of forming connection pads in the manufacturing method according to the first embodiment. As shown here, an outer layer protective film such as solder resist 55 is formed on the first wiring layer 21 and the second wiring layer 22. The wiring layers formed on the glass substrate 60 are collectively referred to as the build-up layer 56. The build-up layer 56 can stack any number of wiring layers as required. Then, a bonding pad 51 for semiconductor elements is formed on the first wiring layer 21, and a bonding pad 53 for the substrate is formed on the second wiring layer 22. Surface treatments such as Ni / Au, Ni / Pd / Au, IT, OSP (water-soluble preflux), etc. are performed on the bonding pad 51 for semiconductor elements and the bonding pad 53 for the substrate, and solder 52 for semiconductor element bonding and solder 54 for substrate bonding are formed as required, thereby completing the multilayer wiring substrate. Note that Ni / Au means using both Ni and Au, and Ni / Pd / Au means using any of Ni, Pd, and Au.

[0073] (Slicing) Next, with reference to FIG. 22, the slicing of the multilayer wiring substrate will be described. FIG. 22 is a cross-sectional view for explaining the slicing process in the manufacturing method according to the first embodiment. FIG. 22(a) shows the case where slicing is performed, and FIG. 22(b) shows the concept of slicing. As shown in FIG. 22(a), slicing is performed along the slicing line 64 where the separation groove 17 is formed by laser or hydrofluoric acid etching. As shown in FIG. 22(b), the substrate portion surrounded by the slicing line 64 corresponds to the multilayer wiring substrate 100. Note that the substrate portion included in the multilayer wiring substrate 100 and separated from the glass substrate 60 is referred to as the core substrate 10. FIG. 22(a) shows the case assuming blade dicing using the blade 72, but in addition to blade dicing, laser, scribing, etc. may also be used. Also, slicing may be performed by combining blade dicing, laser, and scribing. The multilayer wiring substrate 100 is obtained.

[0074] The structures shown in FIGS. 22(a) and 22(b) are in a state where a plurality of multilayer wiring boards 100 are connected via an insulating resin layer 25, so it can also be referred to as a multilayer wiring base substrate. In other words, a multilayer wiring base substrate having a plurality of core substrates 10 having a first surface 20 and a second surface 30 facing the first surface 20, a first wiring layer 21 which is a wiring layer formed on the first surface 20, and a second wiring layer which is a wiring layer formed on the second surface 30, wherein the plurality of core substrates 10 are connected by a resin material filled in a gap (hereinafter also referred to as "fragmentation area") between each core substrate 10, and among the plurality of core substrates, adjacent core substrates are at least partially connected by a member of the same material as the material of the plurality of core substrates in the fragmentation area. The fragmentation area can also be referred to as a separation groove.

[0075] Also, it is possible to say that the structure shown in FIGS. 22(a) and 22(b) is a multilayer wiring base substrate as an intermediate product of the multilayer wiring board 100. That is, the multilayer wiring base substrate includes a base substrate 60 having a first surface 20 and a second surface 30, a first wiring layer region which is a region including a wiring layer formed on the first surface 20, a second wiring layer region which is a region including a wiring layer formed on the second surface 30, a separation groove (fragmentation area) for separating the base substrate 60 into a plurality of core substrates, and in the separation groove (fragmentation area), a core material portion 60a for connecting (joining) adjacent core substrates among the plurality of core substrates.

[0076] In the present invention, since a part of the core material portion 60a of the fragmentation line is removed and the portions of the other core substrates 10 are protected by resin or the like, it is possible to suppress the occurrence of breakage in the core substrates when they are fragmented by dicing or the like.

[0077] (Specifications of Multilayer Wiring Board) Next, with reference to FIGS. 23 and 24, the dimensions of the multilayer wiring board will be described. FIG. 23 is a cross-sectional view showing the multilayer wiring board according to the first embodiment. FIG. 23(a) shows the multilayer wiring board 100 obtained after the singulation process, and FIG. 23(b) schematically shows a perspective view of the multilayer wiring board. In FIG. 23(b), the structure of the side surface of the multilayer wiring board 100 is shown in a simplified manner. Further, FIG. 24 is a cross-sectional view showing the structure of the through electrode among the multilayer substrate wirings according to the first embodiment. The multilayer wiring board 100 has a core substrate 10 having a first surface 20 and a second surface 30 facing the first surface 20, a first wiring layer 21 which is a wiring layer formed on the first surface 20, and a second wiring layer 22 which is a wiring layer formed on the second surface 30. In the plane direction of the first surface 20, the side surface of the multilayer wiring board 100 has a portion where the core substrate is exposed (hereinafter referred to as the "exposed portion") and a portion covered with a substance different from the material of the core substrate (hereinafter referred to as the "coated portion"). This will be specifically described below.

[0078] The side surface of the multilayer wiring board 100 is a surface extending in the direction in which the wiring layers are laminated, and includes the first wiring layer 21, the second wiring layer 22, the insulating resin layer 25 included in the first wiring layer 21 and the second wiring layer 22, and the core material portion 60a. The core material portion 60a corresponds to the exposed portion where the core substrate 10 is exposed. The insulating resin layer 25 is a coated portion that covers the core substrate 10 with an insulating resin which is a material different from the core material.

[0079] In the present disclosure, the coated portion is the resin portion of the insulating resin layer 25, but may be constituted by a substance containing a metal. Also, from the viewpoint of the side surface protection rate, it is preferable that the area of the coated portion is 30% or more and 99% or less of the area of the side surface of the multilayer wiring board 100.

[0080] The thickness wi of the insulating resin on the side portion of the multilayer wiring board 1 is, for example, at least 50 μm or more when measured in the horizontal direction (the direction in which the multilayer wiring board 1 extends). When assuming a vertical straight line from the first surface 20 to the second surface 30 for the side surface of the core board 10 and setting the angle formed by the straight line and the side surface as θ1, starting from the end of the core board 10 of the first wiring layer 21, θ1 inclines within the range of 21° or more and 35° or less to reach the second wiring layer 22. Further, the shape of the side surface of the multilayer wiring board 1 is a shape extending in the same vertical direction as the direction of the vertical straight line.

[0081] The side surface of the multilayer wiring board 1 including the side surface of the core board 10 is partially covered and protected with, for example, a material of insulating resin, although details will be described later. As a result, the stress generated in the first wiring layer 21 or the second wiring layer 22 formed on the upper and lower surfaces of the core board 10 can be dispersed to the other wiring layer through the insulating resin on the side surface of the core board 10. Also, μ cracks and chipping at the end of the core board 10 can be suppressed, and the reliability of the multilayer wiring board 1 can be enhanced.

[0082] The relationship between the opening diameter D1 on the first surface 20 side and the opening diameter D2 on the second surface 30 side of the through electrode 12 (the opening diameter D1 on the first surface side / the opening diameter D2 on the second surface side) is in the range of 0.35 or more and 0.65 or less. By making the opening diameter on the first surface 20 side smaller than the opening diameter on the second surface 30 side, the capacitor electrode 13 can be stably formed on the through electrode 12.

[0083] The thickness of the core board 10 is, for example, in the range of 50 μm or more and 150 μm or less, and it is possible to set the thickness according to the characteristic values of the capacitor electrode 13, inductor, resistor, etc. formed in the first wiring layer 21. When the thickness of the core board 10 becomes 200 μm or more, the relationship between the opening diameter D1 on the first surface 20 side and the opening diameter D2 on the second surface 30 side (the opening diameter D1 on the first surface side / the opening diameter D2 on the second surface side) becomes 0.35 or more and 0.65 or less, making it difficult to form the capacitor electrode 13 on the through electrode 12 and ensure the connection reliability of the through electrode 12. More desirably, the thickness of the core board 10 is in the range of 100 μm or more and 150 μm or less. Note that the relationship between the opening diameter D1 on the first surface 20 side and the opening diameter D2 on the second surface 30 side may be set as appropriate within the above range.

[0084] (Flowchart of the manufacturing method according to the first embodiment) The above-described steps are summarized in a flowchart. FIG. 25 is a diagram showing a flowchart of the manufacturing method according to the first embodiment.

[0085] Step S1 is an adhesion step of the first support. The first support is adhered to the base substrate. In the first embodiment, an adhesive layer containing a hydroxyl group is exemplified. Step S2 is a step of forming a laser modified layer. The laser is irradiated from the surface opposite to the surface to which the first support is adhered. The laser modified portion formed in the laser irradiation portion serves as a starting point for the through holes and the separation grooves. Step S3 is a step of forming the first wiring layer. Electrodes, wirings, capacitors, inductors, etc. can be formed in the first wiring layer. Step S4 is an adhesion step of the second support. The second support is adhered onto the first wiring layer. Step S5 is a step of peeling the first support. The base substrate and the first support are separated from the adhesive layer portion. Step S6 is a step of forming through holes by etching. The portion where the laser modified portion is removed becomes the through hole 11 or the separation groove 17. Also, by adjusting the position of the laser irradiation portion in step S2 and the etching amount in step S6, a part of the base substrate is left as the core material portion 60a in the separation groove 17. In other words, it is possible to say that the etching for forming the separation groove is an etching that stops the etching with the core member remaining only at the bottom portion of the singulation line in a bottom view. Step S7 is a step of forming the second wiring layer. Through electrodes are formed in the through holes of the base substrate, and electrodes and wirings that conduct with the through electrodes are formed. Step S8 is a step of peeling the second support. The second support is separated from the base substrate. Step S9 is a step of forming a build-up layer. Electrodes and wirings are formed on the first wiring layer and the second wiring layer. Step S10 is a step of forming connection pads. After forming a protective film on the first wiring layer and the second wiring layer, connection pads are formed. Step S11 is a singulation step. Dicing or the like is performed on the base substrate to separate the multilayer wiring substrate.

[0086] In the present invention, when producing a through hole in the base substrate in step S6, a separation groove for separating the substrate portion is formed, and a structure is produced in which a part is connected so that the substrate portion does not become independent by the separation groove, thereby suppressing displacement and peeling of the substrate portion.

[0087] <First Modification Example> Next, a manufacturing method as a first modification example will be described with reference to FIGS. 26 to 29. The first modification example is a method of removing the core material on the singulation line 64 that is left in the first embodiment to prevent displacement and peeling from the adhesive layer. Specifically, it is a method of removing the core material portion 60a from the state of FIG. 19.

[0088] First, FIG. 26 is a cross-sectional view for explaining a laser modification portion in the manufacturing method according to the first modification example. Further, FIG. 27 is a cross-sectional view for explaining a step of forming a laser modification portion in the manufacturing method according to the first modification example. From the state of FIG. 19, as shown in FIG. 26, a laser irradiation portion is arranged with respect to the core material portion 60a, and laser modification is performed. At this time, since the insulating resin layer 25 is laminated on the core material portion 60a, the insulating resin portion is removed by laser in advance. FIG. 27 is a cross-sectional view after laser modification of the insulating resin portion. Note that the removal of the insulating resin portion may be performed simultaneously with the laser modification of the core material.

[0089] Next, FIG. 28 is a cross-sectional view for explaining the step of removing the core material by etching in the manufacturing method according to the first modification. As shown in FIG. 28, the core material portion 60a is removed by etching. It is possible to remove the core material portion 60a by the same etching method as that for forming the through holes and the separation grooves.

[0090] Next, FIG. 29 is a cross-sectional view for explaining the step of forming the build-up layer in the manufacturing method according to the first modification. After the etching step of the core material portion 60a, the build-up layer can be formed in the same manner as in the first embodiment, and the multilayer wiring board shown in FIG. 29 can be formed, and singulation can be performed in the same manner as in the first embodiment.

[0091] FIG. 30 is a diagram showing a flowchart of the manufacturing method according to the first modification. In the first modification, after the step of peeling the second support (step S8), the step of removing the core material portion 60a is performed. Other steps are the same as those in the first embodiment.

[0092] According to the first modification, during the process, the positional deviation of the substrate portion can be suppressed by having the core material portion 60a. Further, in the final form, by removing the core material portion 60a, the end portions of the singulated substrate portions can be covered with resin or the like, and cracks can be suppressed.

[0093] <Second Modification> The second modification is different from the first embodiment in that an inductor is formed in the first wiring layer. FIG. 31 is a cross-sectional view showing the multilayer wiring board 100 according to the second modification and a schematic view of the inductor. FIG. 31(a) shows the cross-sectional view of the multilayer wiring board, and FIG. 31(b) shows the schematic view of the inductor. In the following description, the same or equivalent components as those in the above-described first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

[0094] The first wiring layer 121 is composed of three wiring layers, and the second wiring layer 122 is also composed of three wiring layers. FIG. 31(b) is a perspective view of the circuit elements in the portion cl surrounded by the dashed-dotted line in FIG. 31(a). As shown here, the adjacent conduction electrodes 31 are connected via the through-electrode connection portion 41 and the wiring 16, and form a coil integrally. The coil is connected to, for example, the capacitor electrode 13 to exhibit the characteristics of an LC circuit. As a manufacturing method, in the step of forming the first wiring layer, the arrangement of the through-electrode connection portion 41 and the wiring 16 is set so as to form an inductor.

[0095] <Effect> Hereinafter, examples and comparative examples of the multilayer wiring board according to the first embodiment are created and evaluated. For the examples and comparative examples, the presence or absence of the core material portion 60a of the multilayer wiring board and the condition of leaving the core material portion 60a are adjusted, and then the mounting process is performed, and a temperature cycle test is performed. The displacement during the process and the detachment of the substrate after the formation of the separation groove, and the results of the temperature cycle test are evaluated.

[0096] <Example 1> The main conditions for evaluation are as follows. Example 1 was formed by the method of the first embodiment, and two rows of laser irradiation portions were formed at a pitch of 70 μm during the formation of the separation groove (particularly steps S2 and S6 in FIG. 25), and arranged at a pitch of 80 μm in each row. The target value of the hydrofluoric acid etching was Φ80 μm, and as a result, a separation groove with continuous cavity portions as shown in FIG. 6(a) was formed.

[0097] <Example 2> Example 2 was formed by the method of the first embodiment, and the laser irradiation portions were formed in an array at a pitch of 10 μm during the formation of the separation groove, and a separation groove having the shape shown in FIG. 6(c) was formed by not forming a laser modification portion in part. The other parts were formed in the same manner as in Example 1.

[0098] <Example 3> In Example 3, the core material portion 60a of the separation groove was removed using the method of the first modification. The formation of the separation groove in the second surface process (step S6 in FIG. 30) formed a shape in which the cavity portions were continuous using the same method as in Example 1. Subsequently, the formation of the separation groove on the first surface (step S20 in FIG. 30) was performed by forming the laser irradiation portions in an array at a pitch of 10 μm over the entire area of the singulation line 64, and then removing the core material by etching. The formation was performed in the same manner as in Example 1 except as described above.

[0099] <Comparative Example 1> In Comparative Example 1, the core material portion 60a was not formed in Example 2, the laser irradiation portions were formed over the entire area of the singulation line 64, and processing was performed so that each substrate portion was divided by the separation groove. The formation was performed in the same manner as in Example 1 except as described above.

[0100] <Comparative Example 2> In Comparative Example 2, the laser irradiation portions were not formed in the singulation line, and the separation groove was not formed. The formation was performed in the same manner as in Example 1 except as described above.

[0101] Table 1 shows the formation methods and evaluation results of the separation grooves of the examples and comparative examples. For the comprehensive determination, those that passed both the core substrate crack evaluation and the misalignment / peeling evaluation were regarded as OK.

[0102]

Table 1

[0103] First, the results of the core substrate crack test will be explained. The following temperature cycle test was performed. As shown in Table 1, in Examples 1, 2, 3 and Comparative Example 1, no failures occurred even after 1000 cycles. On the other hand, in Comparative Example 2, it passed up to 300 cycles, but failed at 400 cycles. When the failed samples were analyzed, defects such as the occurrence of minute cracks in the core substrate were confirmed. In the passed samples, the occurrence of cracks in the core substrate was suppressed by previously forming separation grooves in the singulation line and protecting the ends of the separation grooves with resin or the like.

[0104] Note that the dicing processing apparatus, temperature cycle test conditions, and evaluation method along the separation groove are as follows. <Substrate Information> Substrate size: Divide a 100 mm × 100 mm substrate into substrate parts of 5 mm × 5 mm size <Dicing Processing> Blade used: R07 - SD600 - BB200 - 75 54 X 0.15A2 X 40 Apparatus used: DAD322 <Temperature Cycle Test> Test conditions: Consider the change from -55°C, RT (room temperature), to 125°C as 1 cycle, hold at each temperature for 30 minutes, and perform up to 1000 cycles. <Evaluation Method> Observation method: Observe the side of the substrate with a metal microscope at magnifications of ×100 and ×500 to evaluate the presence or absence of glass substrate breakage.

[0105] Subsequently, the misalignment and peeling evaluation will be described. When a separation groove is formed, there is an effect of suppressing the breakage of the core material as described above. However, if the core material is completely separated by the separation groove, there is a concern that problems may occur during the process. Specifically, after the etching process shown in the cross - sectional view of FIG. 14, each substrate part is bonded to the second adhesive layer 71 in a state of being divided by the separation groove. In the process until the separation groove 17 is filled with an insulating resin or the like as shown in FIG. 17, the substrate part that becomes the core substrate 10 is exposed, so there is a concern about peeling and misalignment. As an evaluation, the number of pieces peeled during the process and the number of pieces misaligned were counted. The number of substrate parts was set to 1200. For misalignment, the deviation between the center points of the pad position formed on the core material and the via position of the build - up layer after forming one build - up layer was measured.

[0106] FIG. 32 is a cross-sectional view and a plan view at the time of measuring misalignment according to the first embodiment. FIG. 32 shows the steps performed from the peeling step (FIG. 19) of the second support to the formation step (FIG. 20) of the build-up layer. FIG. 32(a) shows a cross-sectional view at the time of measuring misalignment. An insulating resin layer 25 is formed on the through electrode connection portion 42 (hereinafter, also referred to as "via pad"), the second wiring layer 22 is formed, and then via holes 27 are formed by a laser or the like. FIG. 32(b) is an image view of the lower surface of the glass substrate 60 at the time of FIG. 32(a) (when viewed from the -z axis direction). The wiring pattern and the via pad 42 directly above the glass substrate 60 are shown by dotted lines. The via holes 27 formed in the insulating resin layer 25 are shown by solid lines. In reality, the via holes 27 are visible through the insulating resin layer 25. As shown in FIG. 32(b), the center positions of the via pad 42 and the via holes 27 were measured respectively. The amount of deviation was defined as the distance between the center points of the via pad 42 and the via holes 27. When there is no misalignment in the substrate portion, the via holes 27 are formed by a laser or the like with reference to the alignment marks of the underlying wiring pattern, and thus the positioning accuracy of the laser processing is within several μm. On the other hand, when misalignment occurs, since the core substrates that are individual substrate portions are locally misaligned, there are portions where the via pad 42 is largely misaligned. Assuming that the amount of misalignment within the range of normal alignment accuracy during the process is within 15 μm, those with an amount of misalignment of 15 μm or less were considered OK. Those with an amount of misalignment exceeding 15 μm were considered NG. Among the substrate portions that become one piece after singulation, nine in-plane vias were measured, and any one with an amount of misalignment exceeding the above was considered an NG piece. As the judgment criterion, among 1200 pieces, those with 20 or fewer NG pieces were considered qualified.

[0107] In Examples 1, 2, and 3, since the core material part 60a was formed in the separation groove 17, each substrate part did not shift or peel off, and the number of NG occurrences was zero. On the other hand, in Comparative Example 1, since each substrate part was completely separated, peeling and misalignment during the process were confirmed, and the number of NGs was 43, resulting in a non-conformance determination. In Comparative Example 2, since no separation groove was formed, as expected, no peeling or misalignment occurred. From the above results, by forming the core material part 60a in the separation groove, it becomes possible to suppress peeling and misalignment of the sample.

[0108] (Function and Effect) As shown in Table 1, in Examples 1, 2, and 3, no core substrate cracking occurred, and no misalignment or peeling during the process was confirmed. Therefore, by covering a part of the singulation line of the core substrate 10 with resin or the like, high reliability can be ensured, and a multilayer wiring board in which misalignment and peeling during the process are less likely to occur can be formed. Therefore, according to the present disclosure, it becomes possible to suppress misalignment and peeling during the manufacturing process of the multilayer wiring substrate.

[0109] The scope of the present invention is not limited to the illustrated and described exemplary embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible. Furthermore, it includes all embodiments that bring about the same effects as those intended by the present invention.

[0110] For example, although the present disclosure shows forming a laser modified portion after adhering a first support to a glass substrate and then peeling off the first support, it is not limited thereto. For example, a laser modified portion may be formed without using the first support, and in the through-hole forming step, the laser modified portion may be etched to a desired thickness.

[0111] Aspects that may constitute the content of the present invention are described below, but are not limited thereto. (Aspect 1) A plurality of core substrates having a first surface and a second surface facing the first surface, A first wiring layer which is a wiring layer formed on the first surface, A second wiring layer which is a wiring layer formed on the second surface, A multilayer wiring base substrate having The plurality of core substrates are connected by a resin material filled in a gap (hereinafter referred to as "fragmentation area") between each core substrate, Among the plurality of core substrates, adjacent core substrates are at least partially connected by a member of the same material as the material of the plurality of core substrates in the fragmentation area A multilayer wiring base substrate characterized by the above. (Aspect 2) A core substrate having a first surface and a second surface facing the first surface, A first wiring layer which is a wiring layer formed on the first surface, A second wiring layer which is a wiring layer formed on the second surface, A multilayer wiring substrate having The side surface of the multilayer wiring substrate Has a portion where the core substrate is exposed (hereinafter referred to as "exposed portion"), And a portion covered with a substance different from the material of the core substrate (hereinafter referred to as "coated portion") A multilayer wiring substrate characterized by the above. (Aspect 3) The coated portion is composed of a substance containing resin or metal, The multilayer wiring substrate according to aspect 2, characterized by the above. (Aspect 4) Among the areas of the side surface of the multilayer wiring board, the area of the coated portion is 1% or more and 70% or less. The multilayer wiring board according to Aspect 2 or Aspect 3, characterized in that. (Aspect 5) A plurality of core substrates having a first surface and a second surface facing the first surface, A first wiring layer which is a wiring layer formed on the first surface, A second wiring layer which is a wiring layer formed on the second surface, A method for manufacturing a multilayer wiring base substrate having: Forming a laser modified portion on a base substrate which is a base material of the core substrate, By etching the laser modified portion, Forming a separation groove for separating the base substrate into a plurality of core substrates, Leaving a part of the base substrate in the separation groove A method for manufacturing a multilayer wiring base substrate, characterized in that. (Aspect 6) The etching for forming the separation groove, Etching is stopped in a state where only the bottom portion of the singulation line remains with the core member in a bottom view. The method for manufacturing a multilayer wiring base substrate according to Aspect 5, characterized in that. (Aspect 7) After etching the laser modified portion, Singulating the multilayer wiring base substrate along the separation groove The method for manufacturing a multilayer wiring base substrate according to Aspect 5 or Aspect 6, characterized in that. (Aspect 8) A base substrate having a first surface and a second surface, A first wiring layer region which is a region including a wiring layer formed on the first surface, A second wiring layer region which is a region including a wiring layer formed on the second surface, A singulation area for separating the base substrate into a plurality of core substrates, In the singulation area, there is a core material portion for connecting adjacent core substrates among the plurality of core substrates. A multilayer wiring base substrate characterized by the following. (Aspect 9) A plurality of core substrates having a first surface and a second surface facing the first surface, A first wiring layer which is a wiring layer formed on the first surface, A second wiring layer which is a wiring layer formed on the second surface A method for manufacturing a multilayer wiring substrate having: Forming a laser modified portion on a base substrate which is a base material of the core substrate, Etching the laser modified portion, Forming a separation groove for separating the base substrate into the plurality of core substrates, Leaving a part of the base substrate in the separation groove A method for manufacturing a multilayer wiring substrate characterized by the following.

Explanation of symbols

[0112] 1: Multilayer wiring base substrate 100: Multilayer wiring substrate 10: Core substrate 11: Through hole, 11a: Top portion of through hole, 11b: Bottom portion of through hole 12: Through electrode 13: Capacitor electrode 14: Dielectric layer 15: Fluoride resistant metal layer 16: Wiring 17: Separation groove 21, 121: First wiring layer 22, 122: Second wiring layer 25: Insulating resin layer 27: Via hole 31, 32: Conductive electrode 41, 42: Through electrode connection portion (via pad) 51: Bonding pad for semiconductor element 52: Bonding solder for semiconductor element 53: Bonding pad for substrate 54: Bonding solder for substrate 55: Solder resist 56: Build-up wiring layer 60: Glass substrate 60a: Core material portion 61: First support 62: First adhesive layer 63: Laminated structure 64: Singulation line 65: Laser irradiation unit 65a:: Laser modification part 65T: Transfer mark of laser modification part 70: Second support 71: Second adhesive layer 72: Blade

Claims

1. A multilayer wiring base substrate comprising: a plurality of core substrates each having a first surface and a second surface facing the first surface; a first wiring layer which is a wiring layer formed on the first surface; a second wiring layer which is a wiring layer formed on the second surface; wherein the plurality of core substrates are connected by a resin material filled in a gap (hereinafter referred to as "fragmentation area") between the respective core substrates; among the plurality of core substrates, adjacent core substrates are at least partially connected by a member made of the same material as the material of the plurality of core substrates in the fragmentation area A multilayer wiring base substrate characterized by the above.

2. A multilayer wiring substrate comprising: a core substrate having a first surface and a second surface facing the first surface; a first wiring layer which is a wiring layer formed on the first surface; a second wiring layer which is a wiring layer formed on the second surface; wherein the side surface of the multilayer wiring substrate has a portion where the core substrate is exposed (hereinafter referred to as "exposed portion") and a portion covered with a substance different from the material of the core substrate (hereinafter referred to as "coated portion") A multilayer wiring substrate characterized by the above.

3. The coated portion is composed of a substance containing resin or metal. The multilayer wiring substrate according to claim 2, characterized by the above.

4. The area of the coated portion is 30% or more and 99% or less of the area of the side surface of the multilayer wiring substrate. The multilayer wiring substrate according to claim 2, characterized by the above.

5. A method for manufacturing a multilayer wiring base substrate comprising: a plurality of core substrates each having a first surface and a second surface facing the first surface; a first wiring layer which is a wiring layer formed on the first surface; a second wiring layer which is a wiring layer formed on the second surface; wherein a laser modified portion is formed on a base substrate which is a base material of the core substrate; by etching the laser modified portion, a separation groove for separating the base substrate into a plurality of core substrates is formed; a part of the base substrate is left in the separation groove A method for manufacturing a multilayer wiring base substrate characterized by the above.

6. The etching for forming the separation groove stops etching with only the bottom portion of the fragmentation line remaining with the core member in a bottom view. The method for manufacturing a multilayer wiring base substrate according to claim 5, characterized by the above.

7. After etching the laser modified portion, the multilayer wiring base substrate is fragmented along the separation groove. The method for manufacturing a multilayer wiring base substrate according to claim 5, characterized by the above.

8. A base material substrate having a first surface and a second surface, a first wiring layer region which is a region including a wiring layer formed on the first surface, a second wiring layer region which is a region including a wiring layer formed on the second surface, a singulation area for separating the base material substrate into a plurality of core substrates, wherein the singulation area has a core material portion that connects adjacent core substrates among the plurality of core substrates, A multilayer wiring base material substrate characterized by the above.

9. A plurality of core substrates having a first surface and a second surface facing the first surface, a first wiring layer which is a wiring layer formed on the first surface, a second wiring layer which is a wiring layer formed on the second surface, A method for manufacturing a multilayer wiring substrate, comprising: forming a laser modified portion on a base material substrate which is a base material of the core substrate, etching the laser modified portion, forming a separation groove for separating the base material substrate into the plurality of core substrates, leaving a part of the base material substrate in the separation groove, A method for manufacturing a multilayer wiring substrate characterized by the above.

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