Through-electrode substrate and mounting substrate

Abstract

The present disclosure provides a through-electrode substrate including: a core material that includes a first main surface and a second main surface and is provided with a first through-hole that penetrates in a first direction that is the thickness direction; a through-electrode that is filled in the first through-hole; an insulating layer that is disposed on the first main surface side of the core material so as to cover the boundary between the through-electrode and the core material, and is provided with a second through-hole that is connected to the first through-hole; a conductive part that is disposed in the second through-hole and is electrically connected to the through-electrode; and a land part that is disposed around the second through-hole on the surface of the insulating layer on the opposite side from the core material side.

Description

Through-hole electrode substrate and mounting substrate

[0001] The present disclosure relates to a through electrode substrate and a mounting substrate.

[0002] Recently, 2.5D packaging (2.5-dimensional packaging) has been applied to HPC (high-performance computing). Furthermore, in recent years, there has been a demand for higher speeds and lower costs, and substrates with high-density fine wiring, such as FOPLP (fan-out panel-level packaging), have been actively developed. High-density fine wiring substrates are mounted in various electronic devices, such as smartphones and large-scale servers. For example, in an application to a large-scale server, this high-density fine wiring substrate is used as an interposer, and different types of LSIs, such as a CPU and memory, are mounted on the interposer, and this substrate is then mounted on a motherboard.

[0003] In recent years, development of through electrode substrates, which are used as interposers and have through electrodes that connect the front and back surfaces of a substrate, has progressed. In such through electrode substrates, through holes are formed in a core material, and conductive material is disposed inside the through holes by electroplating or the like, to form the through electrodes (see, for example, Patent Document 1). The through electrodes of through electrode substrates are generally classified into a filled type (also called a filled via), in which the entire through hole is filled with a conductive material, and an unfilled type (also called a conformal via), in which a conductive material layer is provided on the side surface of the through hole, forming a hollow.

[0004] JP 2013-4881 A

[0005] In the manufacture of semiconductor packages in which a through hole electrode substrate is interposed between a semiconductor element such as an LSI chip and a motherboard, reflow soldering is performed when mounting the semiconductor element on the through hole electrode substrate or when connecting the through hole electrode substrate to the motherboard. The inventors of the present application have newly discovered that during the heating process of such reflow soldering, a gap may occur between the core material and the through hole electrode due to a difference in thermal expansion between the core material and the through hole electrode, and further, the through hole electrode may bulge relative to the main surface of the core material. When such a gap or bulge occurs, a disconnection may occur in a land portion located near the boundary between the through hole electrode and the core material.

[0006] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a through electrode substrate that can suppress disconnection of land portions.

[0007] The present disclosure provides a through electrode substrate having: a core material including a first main surface and a second main surface located opposite the first main surface, and having a first through hole penetrating in a first direction which is a thickness direction; a through electrode filled in the first through hole; an insulating layer arranged on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole; a conductive portion arranged in the second through hole and electrically connected to the through electrode; and a land portion arranged around the opening of the second through hole on the surface of the insulating layer opposite the core material side, and arranged contiguous with the conductive portion.

[0008] The present disclosure provides a mounting substrate including the through electrode substrate described above and an element mounted on the through electrode substrate.

[0009] The through electrode substrate according to the present disclosure has the effect of being able to suppress disconnection of the land portion.

[0010] FIG. 1 is a schematic cross-sectional view illustrating a through electrode substrate according to the present disclosure. FIG. 2 is a schematic cross-sectional view illustrating a cross-sectional shape of a first through hole according to the present disclosure. FIG. 3 is a schematic cross-sectional view illustrating a method for forming a through electrode according to the present disclosure. FIG. 4 is a schematic cross-sectional view illustrating a method for forming a through electrode according to the present disclosure. FIG. 5 is a schematic cross-sectional view illustrating a through electrode substrate according to the present disclosure. FIG. 6 is a schematic cross-sectional view illustrating a through electrode substrate according to the present disclosure. FIG. 7 is a schematic cross-sectional view illustrating a mounting substrate according to the present disclosure. FIG. 8 is a schematic cross-sectional view illustrating gaps and bulges that occur in a through electrode substrate according to a second embodiment of a through electrode substrate according to the present disclosure. FIG. 9 is a schematic cross-sectional view illustrating a third embodiment of a through electrode substrate according to the present disclosure.

[0011] Below, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be assigned the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0012] In this specification, when describing an aspect in which another component is placed on a component, the terms "above" or "below" are used, unless otherwise specified, to include both cases in which another component is placed directly above or below a component so as to be in contact with the component, and cases in which another component is placed above or below a component via another component. Similarly, in this specification, when the term "on the surface side of a component" is used, unless otherwise specified, it is used to include both cases in which another component is placed directly on the surface of a component so as to be in contact with the surface of the component, and cases in which another component is placed on the surface of a component via another component.

[0013] I. Through-hole electrode substrate The through-hole electrode substrate of the present disclosure includes a core material including a first main surface and a second main surface located opposite the first main surface, and having a first through hole penetrating in a first direction which is a thickness direction, a through electrode filled in the first through hole, an insulating layer disposed on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole, a conductive portion disposed in the second through hole and electrically connected to the through electrode, and a land portion disposed around the opening of the second through hole on the surface of the insulating layer opposite the core material side, and arranged contiguous with the conductive portion.

[0014] FIG. 1 is a schematic cross-sectional view illustrating a through-electrode substrate according to the present disclosure. The through-electrode substrate 10 shown in FIG. 1 includes a core material 1 having a first through hole X1 penetrating in a first direction D1, which is the thickness direction, and a through electrode 11 filled in the first through hole X1. The through-electrode substrate 10 further includes an insulating layer 2 disposed on the first main surface S1 of the core material 1 so as to cover at least the boundary α between the through electrode 11 and the core material 1, the insulating layer 2 having a second through hole X2 connected to the first through hole X1, and a conductive portion 12 disposed in the second through hole X2 and electrically connected to the through electrode. The insulating layer 2 also includes a land portion 13 disposed around the opening of the second through hole X2 on the surface opposite the core material 1 and connected to the conductive portion 12. The land portion 13 is electrically connected to, for example, a wiring layer (not shown).

[0015] 9(a) and 9(b) are schematic diagrams illustrating the state of a through electrode substrate during the heat treatment of reflow soldering. The inventors of the present application have newly discovered that a through electrode substrate having a through electrode 11 filled in a through hole X1 as shown in FIG. 9(a) may have a gap G between the core material 1 and the through electrode 11 during the heat treatment of reflow soldering due to the difference in thermal expansion between the core material 1 and the through electrode 11, as shown in FIG. 9(b). Furthermore, they have newly discovered that the difference in thermal expansion between the core material 1 and the through electrode 11 may cause the through electrode 11 to bulge relative to the main surface of the core material 1. When such a gap or bulge occurs, a land portion located near the boundary between the through electrode and the core material may be disconnected. Furthermore, a wiring layer connected to the land portion may be disconnected.

[0016] According to the present disclosure, as shown in FIG. 1 , the boundary α between the core material 1 and the through electrode 11 is covered by the insulating layer 2. Therefore, it has been found that even if a gap occurs between the through electrode 11 and the core material 1, disconnection of the land portion 13 located on the boundary α can be suppressed. Furthermore, because the insulating layer 2 can absorb the step between the through electrode 11 and the core material 1, the occurrence of a sharp step in the land portion 13 can be suppressed. Therefore, according to the present disclosure, disconnection of the land portion can be suppressed. It is also possible to suppress disconnection of the wiring layer near the land portion.

[0017] The through hole electrode substrate according to the present disclosure has three preferred embodiments, each of which will be described in detail below.

[0018] A. First Embodiment A first embodiment of the present disclosure is a through electrode substrate including: a core material including a first main surface and a second main surface located opposite the first main surface, and having a first through hole penetrating in a first direction, which is a thickness direction; a through electrode filled in the first through hole; an insulating layer disposed on the first main surface side of the core material so as to cover at least a boundary between the through electrode and the core material, and having a second through hole connected to the first through hole; a conductive portion disposed in the second through hole and electrically connected to the through electrode; and a land portion disposed around an opening of the second through hole on a surface of the insulating layer opposite the core material side, the land portion being continuous with the conductive portion; wherein a distance T2 [μm] in the first direction between an interface between the insulating layer and the land portion and an interface between the insulating layer and the core material at an outer periphery of the first through hole satisfies the following formula (1): T2>|(CTE1-CTE2)×260×T1| (1) (wherein CTE1 is the thermal expansion coefficient [ppm / °C] of the material constituting the core material, CTE2 is the thermal expansion coefficient [ppm / °C] of the material constituting the through electrode, and T1 is the thickness [μm] of the core material.)

[0019] The through electrode substrate of this embodiment is characterized in that, as in the example shown in Figure 1 above, the distance T2 [μm] in the first direction D1 between the interface between the insulating layer 2 and the land portion 13 and the interface between the insulating layer 2 and the core material 1 at the outer periphery of the first through hole is within a predetermined range.

[0020] In this way, it was inferred that the effect of step absorption by the insulating layer can be obtained by setting the distance T2 [μm] in the first direction D1 between the interface between the insulating layer 2 and the land portion 13 and the interface between the insulating layer 2 and the core material 1 at the outer periphery of the first through hole X1 to the following formula (1). Therefore, according to this embodiment, it is possible to suppress disconnection of the land portion. It is also possible to suppress disconnection of the wiring layer near the land portion.

[0021] Here, the outer periphery of the first through hole X1 refers to a position on the outer periphery of the first through hole X1 near the core material 1 side, and refers to a position 0.5 mm outside the outer periphery of the first through hole X1 and 0.5 mm or more away from the outer periphery of another through hole (for example, an adjacent first through hole X1). Note that the distance T2 is measured at any five points on the through electrode substrate and is taken as the average value.

[0022] Heat treatment for reflow soldering is generally performed at a maximum temperature of approximately 260°C. Therefore, the value [μm] (hereinafter sometimes referred to as T3) represented by |(CTE1-CTE2) x 260 x T1| in the above formula (1) can be said to be the value of the difference in expansion between the through electrode and the core material when the difference is greatest. If T2 does not satisfy the above range, it is difficult to obtain the effect of step absorption by the insulating layer. The heat treatment temperature for reflow soldering is approximately 260°C for Sn-Ag solder, 280°C for Sn-An solder, and 300°C for An-Si solder.

[0023] The through hole electrode substrate of this embodiment has at least a core material, a through hole electrode, an insulating layer, a conductive portion, and a land portion. Each of the components of the through hole electrode substrate of this embodiment will be described in detail below.

[0024] The through-hole electrode substrate of this embodiment includes a core material having a first main surface S1 and a second main surface S2 located on the opposite side of the first main surface S1, and a first through hole X1 penetrating the core material in a first direction, which is the thickness direction.

[0025] The core material is not particularly limited as long as it is a substrate made of an insulating inorganic material. Examples of such substrates include glass substrates, quartz substrates, sapphire substrates, resin substrates, silicon substrates, silicon carbide substrates, and alumina (Al ２ O ３ ) substrate, aluminum nitride (AlN) substrate, zirconia (ZrO ２ ) substrate, etc. Also, a glass-epoxy resin may be used as the core material.

[0026] Among these, glass substrates are preferred. Because of their excellent flatness, they allow for the formation of fine wiring at narrow pitches. Furthermore, since the thermal expansion coefficient of glass substrates varies depending on their composition, a glass substrate with a preferred thermal expansion coefficient can be selected to match other components.

[0027] The coefficient of thermal expansion CTE1 of the core material is not particularly limited, but is, for example, 1 ppm / ° C. or more, and preferably 2 ppm / ° C. or more. On the other hand, the coefficient of thermal expansion of the core material is 10 ppm / ° C. or less, and preferably 5 ppm / ° C. or less. The coefficient of thermal expansion CTE1 of the material constituting the core material is generally smaller than the coefficient of thermal expansion CTE2 of the material constituting the through electrode.

[0028] The planar shape of the core material is not particularly limited, and examples thereof include rectangular shapes such as a rectangle and a square. The thickness T1 of the core material is, for example, 100 μm or more, or may be 200 μm or more, 300 μm or more, or 400 μm or more. Having the core material thickness within the above range can prevent the core material from bending too much. This prevents the core material from being difficult to handle during the manufacturing process and from warping due to internal stress of a thin film or the like formed on the core material. On the other hand, the thickness of the core material is, for example, 1200 μm or less, or may be 1000 μm or less, or may be 800 μm or less. If the core material thickness is within the above range, the time required for the process of forming the first through hole in the core material can be shortened.

[0029] The planar shape of the first through hole X1 as viewed from the first direction D1 is, for example, substantially circular. The cross-sectional shape of the first through hole X1 as viewed from a direction perpendicular to the first direction D1 can be, for example, the straight shape shown in FIG. 2 . FIG. 2 is a schematic cross-sectional view illustrating an example of the cross-sectional shape of the first through hole. Other cross-sectional shapes of the first through hole include an inverse tapered shape ( FIG. 2( a) ) in which the opening diameter on the first main surface S1 side is larger than the opening diameter on the second main surface S2 side, a forward tapered shape ( FIG. 2( b) ) in which the opening diameter on the first main surface S1 side is smaller than the opening diameter on the second main surface S2 side, an hourglass shape ( FIG. 2( c) ) including a portion where the diameter is minimum at a predetermined position between the first main surface S1 and the second main surface S2, and a bowing shape ( FIG. 2( d) ) in which the diameter is maximum at a predetermined position between the first main surface S1 and the second main surface S2. In this embodiment, either the inverse tapered shape or the hourglass shape is preferred. In addition, in each cross-sectional shape, it is preferable that the edge (E1) of the opening of the first through hole X1 on the first main surface S1 of the core material 1, the edge (E2) of the opening of the first through hole X1 on the second main surface S1, and the minimum and maximum parts of the diameter of the first through hole X1 are curved surfaces having curvature.

[0030] In this embodiment, it is preferable that the central axis of the first through hole substantially coincides with the central axis of the second through hole described later. Furthermore, as shown in FIG. 1 , it is preferable that the opening diameter d1 of the first through hole X1 on the first main surface S1 side is larger than the opening diameter d2 of the second through hole X2 on the core material 1 side described later. d2 / d1 is, for example, 0.5 or more and may be 0.6 or more. On the other hand, d2 / d1 may be, for example, less than 1.0 and 0.9 or less. The opening diameter d1 of the first through hole X1 on the first main surface S1 side is, for example, 50 μm or more and may be 60 μm or more. On the other hand, the opening diameter d1 is, for example, 100 μm or less and may be 90 μm or less.

[0031] The first through hole can be formed by subjecting the core material to processing such as etching, laser processing, sandblasting, or the like, either alone or in combination. In this embodiment, it is preferable to combine laser irradiation and wet etching. Specifically, first, an altered layer is formed in the region of the core material where the first through hole is to be formed by laser irradiation. Next, the core material is immersed in hydrogen fluoride or the like to etch the altered layer. This makes it possible to easily form the first through hole in the core material.

[0032] 2. Through Electrode The through electrode substrate of this embodiment has a through electrode filled in the first through hole. That is, the through electrode substrate of this embodiment has a filled type configuration in which a conductive material fills the entire through hole. The through electrode is made of a conductive material. Examples of conductive materials include metals such as copper, gold, silver, platinum, palladium, rhodium, tin, aluminum, nickel, and chromium, as well as alloys using these metals. In this embodiment, the conductive material is preferably copper.

[0033] The thermal expansion coefficient of the conductive material constituting the through electrode is not particularly limited, but may be, for example, 12 ppm / ° C. or more and 15 ppm / ° C. or more. On the other hand, the thermal expansion coefficient of the conductive material constituting the through electrode may be, for example, 20 ppm / ° C. or less and 18 ppm / ° C. or less.

[0034] As shown in FIG. 6A, the through-hole electrode substrate of this embodiment preferably has an adhesion layer 17 disposed on the inner wall of the first through hole X1. By disposing the adhesion layer, adhesion between the core material and the through-hole electrode is improved. The adhesion layer has higher adhesion to the core material than the through-hole electrode. Although the adhesion layer improves adhesion between the core material and the through-hole electrode to a certain extent, the problem of gaps and swelling during heat treatments such as reflow soldering still occurs even when the adhesion layer is disposed. Furthermore, the adhesion layer may have the role of suppressing diffusion of metal elements in the through-hole electrode into the core material via the sidewall of the first through-hole.

[0035] When the material constituting the through electrode is copper, the material of the adhesion layer can be, for example, titanium, titanium oxide, titanium nitride, molybdenum, molybdenum nitride, tantalum, tantalum nitride, or a laminate of these. Among these, it is preferable that the adhesion layer contains titanium oxide as a main component. The adhesion layer can be formed by a physical film formation method such as vapor deposition or sputtering.

[0036] As shown in FIG. 6B , the adhesion layer 17 is preferably disposed only on the inner wall of the first through hole X1 on the second main surface S2 side. This is because good adhesion between the core material and the through electrode is achieved on the second main surface side of the first through hole X1. The "inner wall of the first through hole X1 on the second main surface S2 side" refers to the inner wall of the first through hole X1 where the ratio (T4 / T1) of the distance T4 from the second main surface to the thickness T1 of the core material is, for example, 0.5 or less. The ratio (T4 / T1) may be 0.3 or less, or 0.2 or less. On the other hand, the ratio (T4 / T1) is, for example, 0.1 or more. If the adhesion layer is disposed only on the inner wall of the first through hole X1 on the second main surface S2 side, the through electrode is more likely to expand toward the first main surface when heated.

[0037] An example of a method for forming a through electrode will be described with reference to Fig. 3. As shown in Fig. 3(a), a first through hole X1 is formed in the core material 1, and then, as shown in Fig. 3(b), a seed layer 15 for forming the through electrode 11 is formed on the second main surface S2. The seed layer can be formed, for example, by sputtering from the second main surface side.

[0038] Next, as shown in FIG. 3( c), a plating layer 16 is grown from the second main surface S2 side by electroplating. By growing the plating layer 16 from the second main surface S2 side, the opening of the first through hole X1 on the second main surface S2 side is blocked by the plating layer 16. At this time, since the cross-sectional shape of the first through hole X1 is inverted tapered, the diameter of the first through hole X1 on the second main surface S2 side is small, so the plating layer 16 can quickly block the opening of the first through hole X1. Next, as shown in FIG. 3( d), the plating layer 16 is grown bottom-up into the first through hole X1 from the first main surface S1 side by electroplating. By growing the plating layer 16 from the first main surface S1 side, the first through hole X1 is buried, i.e., filled, with the plating layer 16. At this time, the cross-sectional shape of the first through hole X1 has an inverted tapered shape, so the plating layer 16 can be efficiently deposited on the sidewall of the first through hole X1.

[0039] As shown in FIG. 3( d ), the plating layer 16 grows excessively onto the first main surface S1. After the first through hole X1 is filled with the plating layer 16, as shown in FIG. 3( e ), the portion of the plating layer 16 that protrudes from the first main surface S1 of the core material 1 is removed by CMP (chemical mechanical polishing). This forms an end face of the plating layer 16 that is flush with the first surface S1. Furthermore, the portion of the seed layer 15 and the plating layer 16 that protrudes from the second main surface S2 of the core material 1 are removed by CMP. This forms an end face of the plating layer 16 that is flush with the first surface S2. As a result of the above, a through electrode 11 is formed in the first through hole X1.

[0040] Another method for forming a through electrode will be described with reference to FIG. 4 . FIG. 4 illustrates a case in which the cross-sectional shape of the first through hole is hourglass-shaped, and an adhesion layer is formed on the inner wall of the first through hole. As shown in FIG. 4( a), a first through hole X1 is formed in the core material 1, and then, as shown in FIG. 4( b), an adhesion layer 17 is formed on the first and second main surfaces S1 and S2 of the core material 1 and on the inner wall of the first through hole X1. Next, as shown in FIG. 4( c), a seed layer 15 for forming the through electrode 11 is formed on the first and second main surfaces S1 and S2 of the core material 1 and on the inner wall of the first through hole X1. The seed layer 15 is formed, for example, by electroless plating.

[0041] Next, as shown in FIG. 4(d), a plating layer 16 is formed by electrolytic plating. By growing the plating layer 16 from the first main surface S1 side and the second main surface S2 side, the first through hole X1 is buried, i.e., filled, with the plating layer 16. Note that, as shown in FIG. 4(e), the plating layer 16 grows excessively onto the first main surface S1 and the second main surface S2. After the first through hole X1 is filled with the plating layer 16, as shown in FIG. 4(f), portions of the adhesion layer 17, seed layer 15, and plating layer 16 that protrude from the first main surface S1 and the second main surface S2 of the core material 1 are removed by CMP (chemical mechanical polishing). This completes the formation of the through electrode 11. As a result, the through electrode 11, which includes the adhesion layer 17, seed layer 15, and plating layer 16, is formed in the first through hole X1.

[0042] 3. Insulating Layer The through-hole electrode substrate of this embodiment has an insulating layer disposed on the first main surface of the core material. The core material and the insulating layer are preferably in direct contact with each other. The insulating layer has a second through hole that penetrates in the first direction and connects to the first through hole.

[0043] The material of the insulating layer is preferably an insulating resin, such as polyimide, polyamide, polyamideimide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyether ether ketone, polyether sulfone, polycarbonate, polyetherimide, epoxy resin, phenol resin, polyphenylene ether, acrylic resin, polyolefin (e.g., polyethylene, polypropylene), polycycloolefin (e.g., polynorbornene), or a liquid crystal polymer compound.

[0044] The method for forming the second through holes is preferably selected appropriately depending on the material of the insulating layer. For example, when the insulating layer is made of a photosensitive material, the second through holes are formed by exposing and developing the insulating layer formed over the entire first main surface of the core material. On the other hand, when the insulating layer is made of a non-photosensitive material, the second through holes are formed by forming a resist pattern on the cover insulating layer formed over the entire surface and etching the portions exposed by the resist pattern. Alternatively, the second through holes may be formed by laser processing the insulating layer, for example.

[0045] 5(a) to 5(c) are schematic cross-sectional views illustrating a through-hole electrode substrate according to this embodiment. Conductive portions and land portions are omitted in FIGS. 5(a) to 5(c). As shown in FIG. 5(a), the second through-hole X2 in the insulating layer 2 is connected to the first through-hole X1 in the core material 1. In this embodiment, it is preferable that the central axis C1 of the first through-hole X1 substantially coincides with the central axis C2 of the second through-hole X2.

[0046] As described above, the opening diameter d2 of the second through hole X2 on the core material 1 side is preferably smaller than the opening diameter d1 of the first through hole X1 on the first main surface S1 side. Furthermore, when viewed from the thickness direction D1, the edge E4 of the opening of the second through hole X2 on the surface of the insulating layer 2 on the core material 1 side is preferably located more inward than the edge E1 of the opening of the first through hole X1 on the first main surface S1 of the core material 1. By arranging an insulating layer having such a second through hole, the boundary α between the core material 1 and the through electrode 11 can be covered by the insulating layer 2.

[0047] The opening diameter d2 of the second through hole X2 on the core material 1 side is not particularly limited, but may be, for example, 40 μm or more, or 50 μm or more, while the opening diameter d2 is, for example, 85 μm or less, or may be, for example, 80 μm or less.

[0048] As shown in FIG. 5B , the cross-sectional shape of the second through hole X2, as viewed perpendicular to the first direction, is preferably an inverted tapered shape in which the opening diameter d2 of the second through hole X2 on the core material 1 side is smaller than the opening diameter d3 on the side opposite the core material side. The inverted tapered shape makes the angle θ between the side wall SS of the second through hole X2 and the surface of the insulating layer 2 opposite the core material 1 side an obtuse angle. Therefore, even if the through electrode 11 expands and bulges, stress concentration near the edge (E3) of the opening of the second through hole X2 on the surface of the insulating layer 2 opposite the core material 1 side can be suppressed. This can suppress disconnection of the land portion and the wiring layer disposed on the insulating layer.

[0049] The angle θ is not particularly limited, but may be, for example, greater than 90 degrees and equal to or greater than 100 degrees. By setting the angle θ within the above range, disconnection of the land portion and the wiring layer can be further suppressed. On the other hand, the angle θ may be, for example, equal to or less than 130 degrees and equal to or less than 120 degrees. If the angle θ is too large, the opening diameter d3 of the second through hole X2 on the side opposite to the core material side becomes large, which may make the second through hole X2 unsuitable for high-density mounting.

[0050] 5(c), in a cross-sectional view seen from a direction perpendicular to the first direction, the edge (E3) of the opening of the second through hole X2 on the surface of the insulating layer 2 opposite to the core material 1 is preferably a curved surface having a curvature. By having the edge (E3) as a curved surface having a curvature, disconnection of the wiring in the land portion and in the vicinity of the land portion can be further suppressed.

[0051] 4. Conductive Portion The through electrode substrate of this embodiment has a conductive portion disposed in the second through hole. The conductive portion is electrically connected to the through electrode and the land portion. The conductive portion is preferably directly connected to the through electrode, and more preferably directly connected to the land portion.

[0052] As shown in Fig. 1, the conductive portion 12 may be filled in the second through hole X2. Alternatively, as shown in Fig. 7, the conductive portion 12 may be formed on the inner wall of the second through hole X2. In this case, there is a space inside the second through hole X2 where no conductive portion 12 exists.

[0053] The conductive portion can be formed by, for example, electrolytic plating. The conductive portion is preferably formed simultaneously with the land portion and the wiring layer. Examples of conductive materials constituting the conductive portion include the same materials as those constituting the through electrodes. The through electrodes and the conductive portion are preferably formed from the same material.

[0054] 5. Land Portion The through electrode substrate of this embodiment has a land portion arranged around the second through hole on the surface of the insulating layer opposite the core material side and arranged continuously with the conductive portion. The land portion is a member used to connect the through electrode to wiring arranged on the through electrode substrate or wiring arranged on another substrate. The planar shape of the land portion is not particularly limited, and may be, for example, the same shape as the opening shape of the second through hole or a different shape. Examples include polygonal shapes such as a circle, an ellipse, a rectangle, a pentagon, and a hexagon. Furthermore, the planar shape of the land portion may be, for example, a shape in which a portion of each of the above shapes is cut out.

[0055] 6. Other Layers The through electrode substrate in this embodiment has a core material and through electrodes, and at least the insulating layer, conductive portion, and land portion described above on the first main surface side of the core material. Furthermore, other layers such as a wiring layer and an interlayer insulating layer may be provided on the first main surface side of the core material.

[0056] (1) Wiring Layer The through-hole electrode substrate of this embodiment preferably has a wiring layer electrically connected to the land portion on the first main surface side of the core material. The wiring layer disposed on the first main surface side may be only one layer or two or more layers. In this embodiment, the wiring layer preferably has a first wiring layer continuous with the land portion. The first wiring layer is preferably disposed in direct contact with the insulating layer. The through-hole electrode substrate of this embodiment may also have only one wiring layer (hereinafter also referred to as the second wiring layer) other than the first wiring layer, or two or more wiring layers. The first wiring layer and the second wiring layer, and the two or more second wiring layers, are preferably stacked in the thickness direction via an interlayer insulating layer. The wiring layers stacked in the thickness direction may be electrically connected via vias.

[0057] The through electrode substrate of this embodiment may have a wiring layer electrically connected to the through electrode on the second main surface side of the core material. The wiring layer arranged on the second main surface side may be only one layer, or may be two or more layers. In the latter case, it is preferable that the two or more wiring layers are stacked in the thickness direction with an interlayer insulating layer interposed therebetween. The wiring layers stacked in the thickness direction may be electrically connected through vias.

[0058] The number of wires in one wiring layer is usually 2 or more, and may be 10 or more, or may be 100 or more. ６ The number of wires in the wiring layer is, for example, 2 to 10. ６ 4 or more, 10 or less ６ It may be 6 or more and 10 or less. ６ It may be 8 or more and 10 or less. ６ It may be 15 or less, and 10 or more. ６ Each wiring usually has a plurality of pads. Furthermore, each wiring preferably has a lead portion that electrically connects the plurality of pads.

[0059] Examples of materials for the wiring include the same materials as those for forming the through electrodes described above.

[0060] The method for forming the wiring layer may be an additive method or a subtractive method. In the additive method, for example, a resist pattern is formed by photolithography, and a plating method is performed on the portions exposed from the resist pattern to obtain a patterned wiring layer. When using electrolytic plating, a conductive layer may be formed on a substrate (e.g., a core material, an interlayer insulating layer) on which the wiring layer is to be formed before forming the resist pattern. In the subtractive method, for example, a resist pattern is formed on a wiring layer formed over the entire surface, and the portions exposed from the resist pattern are etched to obtain a patterned wiring layer.

[0061] The thickness of the wiring layer is, for example, 0.1 μm or more, and may be 0.5 μm or more, 1 μm or more, 3 μm or more, or 5 μm or more. On the other hand, the thickness of the wiring layer may be, for example, 20 μm or less, or 15 μm or less. The thickness of the wiring layer is, for example, 0.1 μm or more to 20 μm or less, 0.5 μm or more to 15 μm or less, 1 μm or more to 15 μm or less, 3 μm or more to 15 μm or less, or 5 μm or more to 15 μm or less. For example, when the wiring layer is formed by a sputtering method, a relatively thin wiring layer can be obtained. Furthermore, when the wiring layer is formed by a plating method, a relatively thick wiring layer can be obtained.

[0062] (2) Interlayer Insulating Layer The through-hole electrode substrate may or may not have an interlayer insulating layer. The through-hole electrode substrate may have only one interlayer insulating layer, or may have two or more interlayer insulating layers. The interlayer insulating layer may be formed between two wiring layers.

[0063] The material of the interlayer insulating layer is preferably an insulating resin. Examples of insulating resins include the same types of insulating resins as those used for the insulating layer described above. The thickness of the interlayer insulating layer is, for example, 1.5 μm or more, and may be 2.5 μm or more. On the other hand, the thickness of the interlayer insulating layer is, for example, 6 μm or less. The thickness of the interlayer insulating layer is, for example, 1.5 μm or more and 6 μm or less, and may be 2.5 μm or more and 6 μm or less. The method for forming the interlayer insulating layer is the same as the method for forming the insulating layer described above.

[0064] (3) Others The through electrode substrate of this embodiment may have the same components as the insulating layer, the conductive portion, the land portion, and the wiring layer arranged on the second main surface side of the core material.

[0065] That is, the insulating layer may have a second insulating layer arranged on the second main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a third through hole connected to the first through hole, a conductive portion arranged within the third through hole, and a land portion arranged around the opening of the third through hole on the surface of the insulating layer opposite the core material side and arranged continuously with the conductive portion, and when the maximum diameter of the end face of the through electrode on the first main surface side is 1, the maximum diameter of the opening of the second through hole on the core material side may be 0.5 or more.

[0066] Here, the third through hole is the same as the second through hole, the second insulating layer is the same as the insulating layer, and the conductive portion, the land portion, and the wiring layer are also the same as those described above, so their explanation will be omitted here.

[0067] B. Second Embodiment Next, a second embodiment of this embodiment will be described. The through electrode substrate of the second embodiment of this embodiment includes a core material including a first main surface and a second main surface located opposite the first main surface, and having a first through hole penetrating in a first direction, which is a thickness direction, a through electrode filled in the first through hole, an insulating layer arranged on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole, a conductive portion arranged in the second through hole and electrically connecting to the through electrode, and a land portion arranged around the opening of the second through hole on the surface of the insulating layer opposite the core material side and arranged continuously with the conductive portion, wherein the maximum diameter of the core material side opening of the second through hole is 0.5 or more when the maximum diameter of the first main surface side end face of the through electrode is 1.

[0068] As described above, in a through electrode substrate, for example, when heat is applied, there is a possibility that the through electrode and the core material may peel off due to a difference in the thermal expansion coefficient between the through electrode arranged in the through hole and the core material, etc. In this case, there is a problem that the land portion or wiring layer electrically connected to the through electrode may be disconnected.

[0069] To address this issue, the inventors arranged an insulating layer at the boundary between the through electrode and the core material so that the land portion and wiring layer would not be disconnected even if the through electrode and the core material were to peel off, and arranged a conductive portion electrically connected to the through electrode, a land portion electrically connected to the conductive portion, and, if necessary, a wiring layer electrically connected to the land portion on the surface of the insulating layer.

[0070] However, when such an insulating layer is provided, the exposed portion of the through electrode is covered with the insulating layer, and therefore, when the through electrode substrate is used as, for example, an interposer, and current is applied to the through electrode, the heat generated is stored in the through electrode because the exposed portion of the through electrode is covered with the insulating layer, and there is a possibility that the temperature of the through electrode itself will rise. When the temperature of the through electrode itself rises in this way, the through electrode thermally expands, pushing up the insulating layer, and as a result, a new problem arises in that the land portion on the insulating layer or the wiring layer may be broken.

[0071] The present embodiment has been made in view of the above circumstances, and has as its main object to provide a through electrode substrate that can suppress disconnection of the land portion.

[0072] 10(a) is a schematic cross-sectional view illustrating a through-hole electrode substrate according to this embodiment. The through-hole electrode substrate 10 shown in FIG. 10(a) includes a first main surface S1 and a second main surface S2 located opposite the first main surface S1. The through-hole electrode substrate 10 includes a core material 1 having a first through hole X1 penetrating in a first direction D1, which is the thickness direction, and a through-hole electrode 11 filled in the first through hole X1. The through-hole electrode substrate 10 further includes an insulating layer 2 disposed on the first main surface S1 side of the core material 1 so as to cover at least the boundary α between the through-hole electrode 11 and the core material 1, the insulating layer 2 having a second through hole X2 connected to the first through hole X1, and a conductive portion 12 disposed in the second through hole X2 and electrically connected to the through-hole electrode. The insulating layer 2 also includes a land portion 13 disposed around the opening of the second through hole X2 on the surface opposite the core material 1 side and connected to the conductive portion 12. The land portion 13 may be electrically connected to a wiring layer (not shown).

[0073] 10(b) shows a plan view of the second through hole X2 of FIG. 10(a). As shown in FIG. 10(b), when the maximum diameter d1 of the end face K1 of the through electrode 11 on the first main surface S1 side (the first main surface side opening K1 of the first through hole X1) is 1, the maximum diameter d2 of the core material 1 side opening K2 of the second through hole X2 is 0.5 or more. For ease of explanation, the conductive portion 12 and the land portion 13 are omitted.

[0074] In the cross-sectional view of the insulating layer 2 in the first direction D1, the end E3 of the insulating layer 2 on the side of the second through hole 12 opposite the core material 1 is positioned between the opening K1 and the opening K2.

[0075] 9(a) and 9(b) are schematic diagrams illustrating the state of a through electrode substrate during the heat treatment of reflow soldering. The inventors of the present application have newly discovered that a through electrode substrate having a through electrode 11 filled in a through hole X1 as shown in FIG. 9(a) may have a gap G between the core material 1 and the through electrode 11 due to the difference in thermal expansion between the core material 1 and the through electrode 11 during the heat treatment of soldering using reflow solder, as shown in FIG. 9(b). Furthermore, they have newly discovered that the difference in thermal expansion between the core material 1 and the through electrode 11 may cause the through electrode 11 to bulge relative to the main surface of the core material 1. When such a gap or bulge occurs, the land portion located near the boundary between the through electrode and the core material, and further the wiring layer electrically connected to the land portion, may be disconnected.

[0076] 10( a), the insulating layer 2 covers the boundary α between the core material 1 and the through electrode 11. Therefore, even if a gap occurs between the through electrode 11 and the core material 1, it has been found that the land portion 13 and the wiring layer (not shown) arranged on the boundary α can be prevented from breaking by being arranged on the insulating layer 2. Furthermore, it has been found that the insulating layer 2 can absorb the step between the through electrode 11 and the core material 1, and therefore it is possible to prevent a sharp step from occurring in the land portion 13 and the wiring layer (not shown).

[0077] However, the through electrode 11 filled in the first through hole X1 has the outer periphery of the end face of the first through hole X1 on the first main surface S1 side covered by the insulating layer 2. Since the insulating layer 2 is made of a resin or the like, it usually has a lower thermal conductivity than metal or the like. Therefore, when a current is applied to the through electrode 11, heat cannot be sufficiently dissipated and heat is accumulated in the through electrode, which may result in an increase in the temperature of the through electrode 11. A new problem has been discovered: when the temperature of the through electrode 11 increases, the through electrode expands thermally and rises, which in turn pushes up the insulating layer 2, potentially causing a break in the land portion 13 or in a wiring layer (not shown) electrically connected to the land portion 13.

[0078] In this embodiment, in order to solve the above problem, when the maximum diameter d1 of the end face K1 (first main surface side opening K1 of the first through hole X1) of the through electrode 11 on the first main surface S1 side is set to 1, the maximum diameter d2 of the core material 1 side opening K2 of the second through hole X2 is set to 0.5 or more, thereby solving the above new problem.

[0079] The through hole electrode substrate of this embodiment has at least a core material, a through hole electrode, an insulating layer, a conductive portion, and a land portion. Each of the components of the through hole electrode substrate of this embodiment will be described in detail below.

[0080] 1. Core Material In the core material of this embodiment, the planar shape of the first through hole X1 as viewed from the first direction D1 shown in FIG. 10 is not particularly limited, and examples thereof include a circular shape, an elliptical shape, a square shape, and a polygonal shape. In this embodiment, a circular shape is preferable because it does not create any areas where stress concentrates, thereby minimizing damage to the core material.

[0081] It is also preferable that the central axis of the first through hole substantially coincides with the central axis of a second through hole, which will be described later.

[0082] In this embodiment, when the maximum diameter d1 of the end face K1 of the through electrode 11 on the first main surface S1 side (the first main surface side opening K1 of the first through hole X1) is set to 1, the maximum diameter d2 (d2 / d1) of the core material 1 side opening K2 of the second through hole X2 is 0.5 or more, preferably 0.6 or more. On the other hand, the above d2 / d1 is, for example, less than 1.0, preferably 0.9 or less.

[0083] The maximum diameter d1 of the first main surface side opening K1 of the first through hole X1 may be 20 μm or more, preferably 50 μm or more, and particularly preferably 60 μm or more. On the other hand, the above d1 is preferably, for example, 100 μm or less, and particularly preferably 90 μm or less. The maximum diameter d2 of the core material 1 side opening K2 of the second through hole X2 may be 10 μm or more, preferably 40 μm or more, and particularly preferably 50 μm or more. On the other hand, the above d2 is preferably, for example, 85 μm or less, and particularly preferably 80 μm or less.

[0084] In this embodiment, the maximum diameter refers to the distance between two opposing positions selected on the outer periphery of the opening K1 or K2 such that the distance between these two positions is the maximum. Specifically, it is the diameter for a circle, the major axis for an ellipse, and the length of the diagonal for a rectangle.

[0085] In this embodiment, it is preferable that the central axis of the first through hole substantially coincides with the central axis of the second through hole, which will be described later.

[0086] Furthermore, an example of the cross-sectional shape of the first through hole X1 as viewed from a direction perpendicular to the first direction is a straight shape as shown in FIG. 2 . FIG. 2 is a schematic cross-sectional view illustrating an example of the cross-sectional shape of the first through hole. Other cross-sectional shapes of the first through hole include an inverse tapered shape ( FIG. 2( a) ) in which the opening diameter on the first main surface S1 side is larger than the opening diameter on the second main surface S2 side, a forward tapered shape ( FIG. 2( b) ) in which the opening diameter on the first main surface S1 side is smaller than the opening diameter on the second main surface S2 side, an hourglass shape ( FIG. 2( c) ) including a portion where the diameter is minimum at a predetermined position between the first main surface S1 and the second main surface S2, and a bowing shape ( FIG. 2( d) ) in which the diameter is maximum at a predetermined position between the first main surface S1 and the second main surface S2. In this embodiment, either the inverse tapered shape or the hourglass shape is preferable. In addition, in each cross-sectional shape, it is preferable that the edge (E1) of the opening of the first through hole X1 on the first main surface S1 of the core material 1, the edge (E2) of the opening of the first through hole X1 on the second main surface S1, and the minimum and maximum parts of the diameter of the first through hole X1 are curved surfaces having curvature.

[0087] Other aspects of the core material in this embodiment, such as the material, planar shape, thermal expansion coefficient, and method of forming the first through hole, are the same as those described in the first embodiment above, so description thereof will be omitted here.

[0088] 2. Through Electrode The through electrode substrate of this embodiment has a through electrode arranged in the first through hole. In this embodiment, the through electrode is a filled type (also called a filled via) in which a conductive material is filled into the entire through hole.

[0089] The through electrode is made of a conductive material, such as a metal such as copper, gold, silver, platinum, palladium, rhodium, tin, aluminum, nickel, or chromium, or an alloy using any of these metals. In this embodiment, the conductive material is preferably copper.

[0090] Other aspects of the through electrode in this embodiment, such as the thermal expansion coefficient, the adhesive layer, and the formation method, are the same as those in the first embodiment, and therefore will not be described here.

[0091] 3. Insulating Layer The insulating layer in this embodiment is the same as in the first embodiment, and therefore a description thereof will be omitted here.

[0092] 4. Conductive Portion The conductive portion in this embodiment is the same as that in the first embodiment, and therefore a description thereof will be omitted here.

[0093] 5. Land Portion The land portion in this embodiment is the same as that in the first embodiment, and therefore a description thereof will be omitted here.

[0094] 6. Other Layers The other layers in this embodiment are the same as those in the first embodiment, and therefore, a description thereof will be omitted here.

[0095] C. Third Embodiment Next, a third embodiment of the through electrode of the present disclosure will be described. The through electrode of this embodiment includes a core material including a first main surface and a second main surface opposite the first main surface, and having a first through hole penetrating in a first direction, which is a thickness direction, a through electrode disposed in the first through hole, an insulating layer disposed on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole, a conductive portion disposed in the second through hole and connected to the through electrode, and a land portion disposed around the opening of the second through hole on the surface of the insulating layer opposite the core material side and arranged continuously with the conductive portion, wherein an angle of an end portion of the insulating layer facing the second through hole on the side opposite the core material in a cross-sectional shape of the insulating layer in the first direction exceeds 90°.

[0096] In the through electrode substrate, for example, when heat is applied, the through electrode and the core material may be separated due to a difference in the thermal expansion coefficient between the through electrode arranged in the through hole and the core material, etc. In this case, there is a problem that the land portion electrically connected to the through electrode and the wiring layer arranged as needed may be disconnected.

[0097] To address this issue, the inventors arranged an insulating layer at the boundary between the through electrode and the core material so that the land portion and the wiring layer arranged as needed would not be disconnected even if the through electrode and the core material were to peel off, and arranged a conductive portion electrically connected to the through electrode and a land portion electrically connected to the conductive portion on the surface of the insulating layer.

[0098] However, even in this case, for example, during a heating process when soldering using reflow solder, the insulating layer may swell due to the difference in thermal expansion coefficient between the through electrode and the core material, which may cause the land portion on the insulating layer to break.

[0099] The present invention has been made in view of the above circumstances, and has as its main object to provide a through electrode substrate that can suppress disconnection of the land portion.

[0100] 11 is a schematic cross-sectional view illustrating a through-hole electrode substrate according to this embodiment. The through-hole electrode substrate 10 shown in FIG. 11 includes a first main surface S1 and a second main surface S2 located opposite the first main surface S1. The through-hole electrode substrate 10 includes a core material 1 having a first through hole X1 penetrating in a first direction D1, which is the thickness direction, and a through-hole electrode 11 disposed within the first through hole X1. The through-hole electrode substrate 10 further includes an insulating layer 2 disposed on the first main surface S1 side of the core material 1 so as to cover at least the boundary α between the through-hole electrode 11 and the core material 1, the insulating layer 2 having a second through hole X2 connected to the first through hole X1, and a conductive portion 12 disposed within the second through hole X2. The insulating layer 2 also includes a land portion 13 disposed around the opening of the second through hole X2 on the surface opposite the core material 1 side and connected to the conductive portion 12. The land portion 13 is electrically connected to, for example, a wiring layer (not shown).

[0101] In the cross-sectional view of the insulating layer 2 in the first direction D1, the angle θ of the end E3 of the insulating layer 2 on the second through hole 12 side opposite the core material 1 is an obtuse angle exceeding 90°.

[0102] 9(a) and 9(b) are schematic diagrams illustrating the state of a through electrode substrate during the heat treatment of reflow soldering. The inventors of the present application have newly discovered that in a through electrode substrate having a through electrode 11 filled in a through hole X1 as shown in FIG. 9(a), a gap G may occur between the core material 1 and the through electrode 11 due to the difference in thermal expansion between the core material 1 and the through electrode 11 during the heat treatment of soldering using reflow solder, as shown in FIG. 9(b). Furthermore, they have newly discovered that the difference in thermal expansion between the core material 1 and the through electrode 11 may cause the through electrode 11 to bulge relative to the main surface of the core material 1. If such a gap or bulge occurs, the land portion located near the boundary between the through electrode and the core material or the wiring layer electrically connected to the land portion may be disconnected.

[0103] According to this embodiment, as shown in FIG. 11 , the boundary α between the core material 1 and the through electrode 11 is covered by the insulating layer 2. Therefore, even if a gap occurs between the through electrode 11 and the core material 1, the land portion 13 and the wiring layer (not shown) located on the boundary α can be prevented from breaking by being disposed on the insulating layer 2. Furthermore, it has been found that the insulating layer 2 can absorb the step between the through electrode 11 and the core material 1, thereby preventing abrupt steps from occurring in the land portion 13 and the wiring layer (not shown). However, a new problem has been found: when the through electrode 11 rises due to the difference in thermal expansion between the through electrode 11 and the core material 1 as described above, depending on the shape of the end E3 of the insulating layer 2 on the second through hole 12 side opposite the core material 1, a break may occur in the land portion 13 or the wiring layer (not shown) electrically connected to the land portion 13. In this embodiment, the angle θ of the end E3 is set to an angle greater than 90°, i.e., an obtuse angle, thereby solving the new problem.

[0104] The through hole electrode substrate of this embodiment has at least a core material, a through hole electrode, an insulating layer, a conductive portion, a land portion, and a wiring layer. Each of the components of the through hole electrode substrate of this embodiment will be described in detail below.

[0105] 1. Core material

[0106] The core material in this embodiment is the same as that in the first embodiment, and therefore a description thereof will be omitted here.

[0107] 2. Through Electrode The through electrode substrate of this embodiment has a through electrode arranged in the first through hole. In this embodiment, the through electrode may be a filled type (also called a filled via) in which a conductive material is filled throughout the through hole, or a non-filled type (also called a conformal via) in which a conductive material layer is provided on the side of the through hole to form a hollow. Among these, the through electrode substrate of this embodiment is preferably a filled type in which a conductive material is filled throughout the through hole, because the thermal expansion of the through electrode described above is likely to cause problems and the effects of this embodiment can be fully exerted.

[0108] In the through electrode substrate of this embodiment, it is preferable that an adhesion layer be disposed on the inner wall of the first through hole X1. By disposing the adhesion layer, adhesion between the core material and the through electrode is improved. The adhesion layer has higher adhesion to the core material than the through electrode. Note that, although the adhesion layer improves adhesion between the core material and the through electrode to a certain extent, problems such as gaps and swelling during heat treatments such as reflow soldering processes still occur even when the adhesion layer is disposed. Furthermore, the adhesion layer may have the role of suppressing diffusion of metal elements in the through electrode into the core material through the sidewall of the first through hole.

[0109] When the material constituting the through electrode is copper, the material of the adhesion layer can be, for example, titanium, titanium oxide, titanium nitride, molybdenum, molybdenum nitride, tantalum, tantalum nitride, or a laminate of these. Among these, it is preferable that the adhesion layer contains titanium oxide as a main component. The adhesion layer can be formed by a physical film formation method such as vapor deposition or sputtering.

[0110] Other aspects of the through electrodes in this embodiment, such as the material, thermal expansion coefficient, and formation method, are the same as those in the first embodiment, and therefore will not be described here.

[0111] 3. Insulating Layer The through hole electrode substrate of this embodiment has an insulating layer disposed on the first main surface of the core material. The core material and the insulating layer are preferably in direct contact with each other. The insulating layer has a second through hole that penetrates in the first direction and connects to the first through hole.

[0112] In this embodiment, as shown in Figures 11 and 5(b), in the cross-sectional view of the insulating layer 2 when the insulating layer 2 is cut along the first direction D1, it is preferable that the angle θ of the end E3 of the insulating layer 2 on the side of the second through hole X2 opposite the core material 1 is an angle greater than 90°, i.e., an obtuse angle.

[0113] In this embodiment, the lower limit of the angle of the end E3 is preferably 95° or more, and particularly preferably 120° or more. On the other hand, the upper limit of the angle is preferably 175° or less, and particularly preferably 160° or less. Within the above range, when the through electrode 11 bulges due to a difference in thermal expansion with the core material 1, the shape of the end E3 has the effect of suppressing disconnection of the land portion 13 or the wiring layer (not shown).

[0114] In this embodiment, the angle of the end E3 is measured as follows: The specimen is cut along the first direction D1 at a position where the distance between the opening of the second through hole X2 on the side opposite the core material 1 is greatest (or, if the opening is circular, at the position where the distance is the diameter), and the cross-sectional shape is imaged using an electron microscope. In the image obtained, the angle of the intersection between a straight line formed on the surface of the insulating layer 2 opposite the core material 1 (hereinafter referred to as the top surface) and a straight line formed on a surface of the insulating layer 2 facing the core material 1, which extends from the edge E2 of the opening of the second through hole X2 toward the top surface (hereinafter referred to as the side surface), is measured, and this angle is defined as the angle of the end E3.

[0115] Here, if the line formed by the side surface is curved, the angle is determined using the tangent at the position where the thickness of the insulating layer is half. On the other hand, if the line formed by the top surface is curved, the angle is measured using the tangent at the inflection point of the curve on the top surface. The angle of the end E3 is determined as the average value of the values ​​measured at five different second through holes X2.

[0116] In this embodiment, the angle of the end E3 of the insulating layer 2 can be set within the above range, for example, by adjusting the exposure conditions (exposure amount, exposure time, wavelength, and gap between the photomask and the insulating layer) or adjusting the opening pattern of the photomask when the insulating layer is formed using a photolithography method.

[0117] In this embodiment, it is preferable that the end E3 of the insulating layer 2 is formed of a curved surface, i.e., that the cross-sectional shape is formed of a curved line, as shown in Fig. 5(c) , because this makes it possible to further suppress breakage of the land portion, etc.

[0118] Here, the end E3 can be curved by adjusting the conditions in the photolithography method described above or by using a melt-flowable material.

[0119] As described above, the opening diameter d2 of the second through hole X2 on the core material 1 side is smaller than the opening diameter d1 of the first through hole X1 on the first main surface S1 side. In addition, in plan view, the edge E4 of the opening of the second through hole X2 on the surface of the insulating layer 2 on the core material 1 side is located more inward than the edge E1 of the opening of the first through hole X1 on the first main surface S1 of the core material 1. By arranging an insulating layer having such a second through hole, the boundary α between the core material 1 and the through electrode 11 can be covered by the insulating layer 2.

[0120] The opening diameter d2 of the second through hole X2 on the core material 1 side is not particularly limited, but may be, for example, 40 μm or more, or 50 μm or more, while the opening diameter d2 is, for example, 85 μm or less, or may be, for example, 80 μm or less.

[0121] The cross-sectional shape of the second through hole X2 when cut in the first direction is preferably an inverted tapered shape, for example, as shown in Figure 5 (b), in which the opening diameter d2 on the core material 1 side of the second through hole X2 is smaller than the opening diameter d3 on the opposite side to the core material side.

[0122] Other aspects of the insulating layer in this embodiment, such as the material, the forming method, the cross-sectional shape, etc., are the same as those in the first embodiment, and therefore will not be described here.

[0123] 4. Conductive Portion The conductive portion in this embodiment is the same as that in the first embodiment, and therefore a description thereof will be omitted here.

[0124] 5. Land Portion The land portion in this embodiment is the same as that in the first embodiment, and therefore a description thereof will be omitted here.

[0125] 6. Other Layers The other layers in this embodiment are the same as those in the first embodiment, and therefore, a description thereof will be omitted here.

[0126] II. Mounting Substrate Next, the mounting substrate of the present disclosure will be described. The mounting substrate of the present disclosure includes the through electrode substrate described above and an element mounted on the through electrode substrate.

[0127] Fig. 8 is a schematic cross-sectional view showing an example of a mounting substrate in this embodiment. The mounting substrate 20 shown in Fig. 8 includes the above-mentioned through electrode substrate 10 and an element 30 mounted on the through electrode substrate. The element 30 has a terminal 31 connected to the conductive portion 5 of the through electrode substrate 10. In Fig. 8, a plurality of wiring layers 7 are stacked with an interlayer insulating layer 6 interposed therebetween.

[0128] According to this embodiment, by using the through electrode substrate described above, disconnection of the land portion and the wiring layer in the through electrode substrate is suppressed, and therefore a highly reliable mounting substrate can be obtained.

[0129] 1. Through Electrode Substrate The through electrode substrate in this embodiment is the same as that described above in "I. Through Electrode Substrate," and therefore will not be described here.

[0130] 2. Element In this embodiment, the element is a component mounted on the through-hole electrode substrate. Examples of the element include an LSI chip such as a logic IC or a memory IC. The element 30 may also be a MEMS (Micro Electro Mechanical Systems) chip. A MEMS chip is an electronic device in which mechanical components, sensors, actuators, electronic circuits, and the like are integrated on a single substrate.

[0131] 3. Mounting Board The use of the mounting board in this embodiment is not particularly limited, but it is mounted on, for example, a notebook personal computer, a tablet terminal, a mobile phone, a smartphone, a digital video camera, a digital camera, a digital clock, a server, and the like.

[0132] It should be noted that the present embodiment is not limited to the above-described embodiment, which is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present embodiment and exhibits similar effects is included in the technical scope of the present embodiment.

[0133] A. Example of the First Embodiment [Example 1-1] The through-hole electrode substrate shown in FIG. 6(b) was fabricated. A glass substrate (thermal expansion coefficient CTE1 3 ppm / °C, thickness T1 400 μm) was used as the core material 1, and a first through-hole with a straight cross-sectional shape was formed. An adhesion layer primarily composed of titanium oxide was formed on the inner wall of the first through-hole X1 on the second main surface S2 side. Next, a conductive material was filled into the first through-hole to form a through-hole electrode. Copper (thermal expansion coefficient CTE2 17 ppm / °C) was used as the conductive material constituting the through-hole electrode 11. Next, an insulating layer was formed on the entire first main surface side of the core material using a negative photosensitive polyimide resin as the insulating layer material. The insulating layer formed on the entire surface was exposed and developed to form a second through-hole with a reverse-tapered cross-sectional shape. In this case, the second through-hole was formed so that at least the boundary between the through-hole and the core material was covered with the insulating layer. Next, a conductive portion was placed in the second through hole, and a land portion and a wiring layer were formed. In the manufactured through hole electrode substrate, the distance T2 in the first direction between the interface between the insulating layer and the land portion and the interface between the insulating layer and the through hole electrode was measured at five locations around the periphery of the first through hole, and the average value was calculated to be 1.56 μm. Furthermore, T3 calculated from the above-mentioned formula (1) was 1.45 μm.

[0134] [Example 1-2] A through-hole electrode substrate was fabricated in the same manner as in Example 1-1, except that a glass substrate having a thickness T1 of 800 μm was used as the core material, and the distance T2 in the first direction between the interface between the insulating layer and the land portion and the interface between the insulating layer and the through-hole electrode was set to 3.12 μm. Note that T3 calculated from the above-mentioned formula (1) was 2.91 μm.

[0135] [Example 1-3] A through-hole electrode substrate was fabricated in the same manner as in Example 1-1, except that a glass substrate having a thickness T1 of 1200 μm was used as the core material, and the distance T2 in the first direction between the interface between the insulating layer and the land portion and the interface between the insulating layer and the through-hole electrode was set to 4.68 μm. Note that T3 calculated from the above-mentioned formula (1) was 4.37 μm.

[0136] [Comparative Example 1-1] A through-hole electrode substrate was fabricated in the same manner as in Example 1-1, except that the distance T2 in the first direction between the interface between the insulating layer and the land portion and the interface between the insulating layer and the through-hole electrode was set to 1.00 μm. Note that T3 calculated from the above-mentioned formula (1) was 1.45 μm.

[0137] [Evaluation] The through hole electrode substrates prepared above were heated with a profile that maintained a peak temperature of 260°C for 3 minutes. The presence or absence of breaks in the land portion and the wiring layer was confirmed. No breaks occurred in any of the examples. On the other hand, breaks were confirmed in the land portion and the wiring layer near the land portion in the comparative example.

[0138] B. Example of the second embodiment

[0139] Example 2-1: A glass substrate (400 μm thick) was used as the core material, and a first through hole with a straight cross-sectional shape was formed. An adhesive layer primarily composed of titanium oxide was formed on the inner wall of the first through hole. Next, a conductive material was filled into the first through hole to form a through electrode. Copper was used as the conductive material constituting the through electrode. Next, an insulating layer was formed entirely on the first main surface side of the core material using a negative photosensitive polyimide resin as the insulating layer material. The insulating layer formed entirely on the first main surface side was exposed and developed to form a second through hole with an inverted cross-sectional shape. Next, a conductive portion was disposed in the second through hole, and a land portion and a wiring layer were formed. In this example, the maximum diameter d1 of the opening on the first main surface side of the first through hole was 85.0 μm, and the maximum diameter d2 of the opening on the core material side of the second through hole was 42.5 μm.

[0140] Example 2-2 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 43.0 μm.

[0141] Example 2-3 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 50.0 μm.

[0142] Example 2-4 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 60.0 μm.

[0143] Example 2-5 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 70.0 μm.

[0144] Example 2-6 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 84.0 μm.

[0145] Comparative Example 2-1 A through electrode substrate was formed in the same manner as in Example 1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 20.0 μm.

[0146] Comparative Example 2-2 A through electrode substrate was formed in the same manner as in Example 2-1, except that the maximum diameter d2 of the opening of the second through hole on the core material side was formed to be 30.0 μm.

[0147] Comparative Example 2-3 A through electrode substrate was formed in the same manner as in Example 2-1, except that the maximum diameter d2 of the opening of the second through hole on the core material side was 40.0 μm.

[0148] Comparative Example 2-4 A through electrode substrate was formed in the same manner as in Example 2-1, except that the second through holes were formed so that the maximum diameter d2 of the openings on the core material side was 42.0 μm.

[0149] Comparative Example 2-5 A through electrode substrate was formed in the same manner as in Example 2-1, except that the maximum diameter d2 of the opening of the second through hole on the core material side was 85.0 μm.

[0150] [Measurement of Allowable Current] For each example and comparative example, the current density that causes a temperature rise of 10° C. in the through electrode was measured as the allowable current.

[0151] The allowable current is the current value that causes a 10°C temperature rise in the through electrode. The temperature rise is the difference between the temperature of the through electrode when no current is flowing and the temperature of the through electrode when an allowable current is flowing. In the through electrode substrates of Examples 1-6 and Comparative Examples 1-5, the allowable current was calculated by measuring the temperature of the through electrode while changing the current value flowing through the through electrode. The temperature of the through electrode was measured 10 minutes after the current value was changed. An I-V meter SPST-A1A manufactured by Togami Electric was used as the device for passing current through the through electrode. A thermograph was used to measure the temperature of the through electrode. An infrared camera Optris PI 450 was used as the thermograph.

[0152] [Evaluation] (1) Pattern Misalignment After measuring the allowable current (current density), the presence or absence of pattern misalignment was evaluated. For the evaluation, a length measuring microscope was used to check for the presence or absence of pattern misalignment between the conductive portion and the through electrode, and the case where pattern misalignment occurred was rated as "present," and the case where pattern misalignment did not occur was rated as "absent."

[0153] (2) Presence or absence of disconnection in land portion A current of 0.10 A to 0.20 A was applied to the through hole electrode substrates of Examples 1-6 and Comparative Examples 1-5 in 0.01 A increments for 10 minutes each, and the presence or absence of disconnection in the land portion was examined using a length measuring microscope. Cases where there was no disconnection were rated "A", and cases where there was a disconnection were rated "B". The results are shown in Table 1.

[0154] Current density* = Maximum current within a current rise of 10°C

[0155] Thus, the present disclosure provides, for example, the following inventions.

[0156] [1] A through-hole electrode substrate comprising: a core material including a first main surface and a second main surface opposite to the first main surface, and having a first through hole penetrating in a first direction, which is a thickness direction; a through electrode filled in the first through hole; an insulating layer disposed on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole; a conductive portion disposed in the second through hole and electrically connected to the through electrode; and a land portion disposed around an opening of the second through hole on a surface of the insulating layer opposite to the core material side, the land portion being continuous with the conductive portion. [2] The through-hole electrode substrate according to [1], wherein a distance T2 [μm] in the first direction between an interface between the insulating layer and the land portion and an interface between the insulating layer and the core material at an outer periphery of the first through hole satisfies the following formula (1): T2>|(CTE1-CTE2)×260×T1| (1) (wherein CTE1 is the coefficient of thermal expansion [ppm / °C] of a material constituting the core material, CTE2 is the coefficient of thermal expansion [ppm / °C] of a material constituting the through electrode, and T1 is the thickness [μm] of the core material.) [3] The through electrode substrate according to [1], wherein, when the maximum diameter of the end face on the first main surface side of the through electrode is taken as 1, the maximum diameter of the core material-side opening of the second through hole is 0.5 or more. [4] The through electrode substrate according to [1], wherein, in a cross-sectional shape of the insulating layer in the first direction, an end of the insulating layer on the second through hole side opposite to the core material forms an angle exceeding 90°. [5] The through electrode substrate according to any of [1] to [4], wherein the core material is a glass substrate. [6] The through-hole electrode substrate according to any one of [1] to [5], wherein the cross-sectional shape of the second through-hole, as viewed from a direction perpendicular to the first direction, is an inverted tapered shape. [7] The through-hole electrode substrate according to any one of [1] to [6], wherein the through-hole electrode substrate has a wiring layer electrically connected to the land portion. [8] The through-hole electrode substrate according to [2], wherein an adhesion layer is disposed on the inner wall of the first through-hole on the second main surface side. [9] The through-hole electrode substrate according to [8], wherein the adhesion layer contains titanium oxide as a main component.

[10] The through electrode substrate according to [2], wherein, in a cross-sectional view seen from a direction perpendicular to the first direction, an edge of an opening of the second through hole on a surface of the insulating layer opposite to the core material is a curved surface having a curvature.

[11] The through electrode according to [3], wherein the through electrode is made of a metal containing copper as a main component.

[12] The through electrode substrate according to [3], wherein, when the maximum diameter of the end face of the through electrode on the first main surface side is 1, the maximum diameter of the opening of the second through hole on the core material side is 0.6 or more.

[13] The through-hole electrode substrate according to [3], comprising: a second insulating layer disposed on the second main surface side of the core material so as to cover at least the boundary between the through-hole electrode and the core material, and having a third through hole connected to the first through hole; a conductive portion disposed in the third through hole and electrically connected to the through-hole electrode; and a land portion disposed around the opening of the third through hole on the surface of the insulating layer opposite to the core material side and arranged continuously with the conductive portion, wherein the maximum diameter of the core material-side opening of the third through hole is 0.5 or more when the maximum diameter of the second main surface side end face of the through-hole electrode is 1.

[14] The through-hole electrode substrate according to [4], in which the through-hole electrode is filled in the first through hole.

[15] The through-hole electrode substrate according to [4], in which the end portion of the insulating layer facing the second through hole on the opposite side to the core material in a cross-sectional shape in the first direction is curved.

[16] The through-hole electrode substrate according to [4], wherein, in a cross-sectional shape of the insulating layer in the first direction, an angle of an end portion of the insulating layer on the side of the second through hole opposite to the core material is 95° or more and 175° or less.

[17] The through-hole electrode substrate according to [4], comprising: a second insulating layer arranged on the second main surface side of the core material so as to cover at least a boundary between the through-hole and the core material, and having a third through hole connected to the first through hole, a conductive portion arranged in the third through hole, and a land portion arranged around an opening of the third through hole on a surface of the insulating layer opposite to the core material side and arranged contiguous with the conductive portion, wherein, in a cross-sectional shape of the second insulating layer in the first direction, an angle of an end portion of the second insulating layer on the side of the third through hole opposite to the core material is an angle greater than 90°.

[18] A mounting substrate comprising: the through-hole electrode substrate according to any one of [1] to

[17] ; and an element mounted on the through-hole electrode substrate.

[0157] REFERENCE SIGNS LIST 1... Core material X1... First through hole 2... Insulating layer X2... Second through hole 11... Through electrode 12... Conductive portion 13... Land portion 10... Through electrode substrate 20... Mounting substrate 30... Element

Claims

1. A through electrode substrate comprising: a core material including a first main surface and a second main surface opposite to the first main surface, and having a first through hole penetrating in a first direction which is a thickness direction; a through electrode filled in the first through hole; an insulating layer disposed on the first main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a second through hole connected to the first through hole; a conductive portion disposed in the second through hole and electrically connected to the through electrode; and a land portion disposed around the opening of the second through hole on the surface of the insulating layer opposite to the core material side, and disposed contiguous with the conductive portion.

2. The through hole electrode substrate according to claim 1, wherein a distance T2 [μm] in the first direction between an interface between the insulating layer and the land portion and an interface between the insulating layer and the core material at the outer periphery of the first through hole satisfies the following formula (1): T2>|(CTE1-CTE2)×260×T1| (1) (wherein CTE1 is the thermal expansion coefficient [ppm / °C] of the material constituting the core material, CTE2 is the thermal expansion coefficient [ppm / °C] of the material constituting the through hole, and T1 is the thickness [μm] of the core material.) 3. The through electrode substrate according to claim 1, wherein the maximum diameter of the opening of the second through hole on the core material side is 0.5 or more when the maximum diameter of the end face on the first main surface side of the through electrode is 1.

4. The through electrode substrate according to claim 1, wherein the angle of the end of the insulating layer on the second through hole side opposite the core material in the cross-sectional shape of the insulating layer in the first direction is an angle greater than 90°.

5. The through hole electrode substrate according to claim 1, wherein the core material is a glass substrate.

6. The through electrode substrate according to claim 1, wherein the cross-sectional shape of the second through hole when viewed from a direction perpendicular to the first direction is an inverted tapered shape.

7. The through electrode substrate according to claim 1, further comprising a wiring layer electrically connected to the land portion.

8. The through electrode substrate according to claim 2, wherein an adhesive layer is disposed on an inner wall of the first through hole on the second main surface side.

9. The through hole electrode substrate according to claim 8, wherein the adhesion layer contains titanium oxide as a main component.

10. A through-hole electrode substrate as described in claim 2, wherein, in a cross-sectional view perpendicular to the first direction, the edge of the opening of the second through hole on the surface of the insulating layer opposite the core material is a curved surface having a curvature.

11. The through electrode according to claim 3, wherein the through electrode is made of a metal containing copper as a main component.

12. The through electrode substrate according to claim 3, wherein the maximum diameter of the opening of the second through hole on the core material side is 0.6 or more, assuming that the maximum diameter of the end face of the through electrode on the first main surface side is 1.

13. A through electrode substrate as described in claim 3, comprising: a second insulating layer arranged on the second main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a third through hole connected to the first through hole; a conductive portion arranged within the third through hole and electrically connecting to the through electrode; and a land portion arranged around the opening of the third through hole on the surface of the insulating layer opposite the core material side and arranged contiguous with the conductive portion, wherein when the maximum diameter of the end face on the second main surface side of the through electrode is 1, the maximum diameter of the opening of the third through hole on the core material side is 0.5 or more.

14. The through electrode substrate according to claim 4, wherein the through electrode is filled in the first through hole.

15. The through electrode substrate according to claim 4, wherein an end portion of the insulating layer on the side of the second through hole opposite the core material in a cross-sectional shape in the first direction is curved.

16. The through electrode substrate according to claim 4, wherein the angle of the end of the insulating layer on the second through hole side opposite the core material in the cross-sectional shape of the insulating layer in the first direction is 95° or more and 175° or less.

17. A through electrode substrate as described in claim 4, comprising: a second insulating layer arranged on the second main surface side of the core material so as to cover at least the boundary between the through electrode and the core material, and having a third through hole connected to the first through hole; a conductive portion arranged within the third through hole; and a land portion arranged around the opening of the third through hole on the surface of the insulating layer opposite the core material side and arranged contiguous with the conductive portion, wherein the angle of the end of the second insulating layer on the third through hole side opposite the core material in the cross-sectional shape of the second insulating layer in the first direction exceeds 90°.

18. A mounting board comprising: a through electrode substrate according to any one of claims 1 to 17; and an element mounted on the through electrode substrate.

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