Through-hole electrode substrate, manufacturing method thereof, and mounting substrate

Abstract

To provide a through electrode substrate capable of arranging elements in an area of a substrate where through holes are provided, and a method for manufacturing the same.SOLUTION: A through electrode substrate includes a substrate 12 including a first surface 13 and a second surface 14 located opposite to the first surface and provided with a through hole 20, and a through electrode provided inside the through hole of the substrate. The through electrode includes a first portion 23 extending along the side wall of the through hole, and a second portion 24 connected to the first portion, extending in the planar direction of the first surface so as to contact the side wall of the through hole on the first surface side of the substrate, and having a thickness greater than that of the first portion. A hollow portion exists inside the through hole between the opposing surfaces of the first portion.SELECTED DRAWING: Figure 22

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a through-electrode substrate and a method for manufacturing the same. Further, embodiments of the present disclosure relate to a mounting substrate including the through-electrode substrate.

Background Art

[0002] A member including a substrate having a first surface and a second surface, a plurality of through-holes provided in the substrate, and electrodes provided inside the through-holes, that is, a so-called through-electrode substrate, is used in various applications. For example, the through-electrode substrate is used as an interposer interposed between two LSI chips when stacking a plurality of LSI chips to increase the mounting density of the LSI. Further, the through-electrode substrate may be interposed between an element such as an LSI chip and a mounting substrate such as a mother board. In the following description, the electrode provided inside the through-hole may also be referred to as a through-electrode.

[0003] As examples of through-electrodes, so-called field vias and conformal vias are known. In the case of a field via, the through-electrode includes a conductive material such as copper filled inside the through-hole. FIG. 37 shows an example of a through-electrode substrate including a through-electrode 22 configured as a field via. In the case of a conformal via, the through-electrode includes, for example, as disclosed in Patent Document 1, a wall surface conductive layer extending along the side wall of the hole, a first surface conductive layer provided on the first surface of the substrate, and a second surface conductive layer provided on the second surface of the substrate. FIG. 38 shows an example of a through-electrode substrate including a through-electrode 22 configured as a conformal via.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In order to effectively utilize the surface area of the through - electrode substrate, it is preferable that elements such as LSI chips can be arranged in the region of the substrate where the through - holes are provided. However, in the case of conformal vias, since the through - electrodes are located on the wall surface of the through - holes and the surface of the substrate, elements cannot be arranged in the region of the substrate where the through - holes are provided.

[0006] Embodiments of the present disclosure have been made in consideration of such points, and an object thereof is to provide a through - electrode substrate in which elements can be arranged in the region of the substrate where the through - holes are provided, and a method for manufacturing the same.

[0007] One embodiment of the present disclosure includes a step of preparing a substrate including a first surface and a second surface located on the opposite side of the first surface and provided with through - holes, a step of providing a sealing layer on the first surface of the substrate to close the through - holes, and an electrode forming step of forming a through - electrode having a first portion extending along the side wall of the through - hole and a second portion connected to the first portion and spreading along the sealing layer inside the through - hole, and a step of removing the sealing layer. It is a method for manufacturing a through - electrode substrate.

[0008] The method for manufacturing a through - electrode substrate according to an embodiment of the present disclosure may further include a step of forming a wiring layer having a conductive layer connected to the second portion of the through - electrode on the first - surface side of the substrate.

[0009] In the method for manufacturing a through - electrode substrate according to an embodiment of the present disclosure, in the plane direction of the first surface of the substrate, the dimension of the portion of the conductive layer of the wiring layer connected to the second portion of the through - electrode may be smaller than the dimension of the second portion of the through - electrode.

[0010] In the method for manufacturing a through - electrode substrate according to an embodiment of the present disclosure, the conductive layer may include an electrode portion that overlaps the second portion of the through - electrode and has a contour surrounded by the second portion when viewed along the normal direction of the first surface of the substrate.

[0011] In the method for manufacturing a through-electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a plurality of the electrode portions.

[0012] In the method for manufacturing a through-electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a lead wire portion that intersects the contour of the second portion of the through-electrode when viewed along the normal direction of the first surface of the substrate.

[0013] In the method for manufacturing a through-electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a plurality of the lead wire portions.

[0014] In the method for manufacturing a through-electrode substrate according to an embodiment of the present disclosure, the substrate may include glass.

[0015] An embodiment of the present disclosure includes a substrate including a first surface and a second surface located on the opposite side of the first surface and provided with a through-hole, and a through-electrode provided inside the through-hole of the substrate. The through-electrode has a first portion that spreads along the side wall of the through-hole, and a second portion that is connected to the first portion and spreads in the plane direction of the first surface so as to contact the side wall of the through-hole on the first surface side of the substrate. A hollow portion exists between the surfaces of the first portions facing each other inside the through-hole. It is a through-electrode substrate.

[0016] In the through-electrode substrate according to an embodiment of the present disclosure, the second portion of the through-electrode may be located on the same plane as the first surface of the substrate.

[0017] In the through-electrode substrate according to an embodiment of the present disclosure, the dimension of the through-hole in the plane direction of the first surface of the substrate may increase as it goes from the first surface toward the second surface.

[0018] In the through-electrode substrate according to an embodiment of the present disclosure, the substrate may include glass.

[0019] In a through - electrode substrate according to an embodiment of the present disclosure, a plurality of the through - holes and a plurality of the through - electrodes are formed in the substrate, and on the first surface of the substrate, the second portions of the through - electrodes may be uniformly distributed.

[0020] A through - electrode substrate according to an embodiment of the present disclosure may further include a wiring layer provided on the first - surface side of the substrate and having a conductive layer connected to the second portion of the through - electrode.

[0021] In a through - electrode substrate according to an embodiment of the present disclosure, in the plane direction of the first surface of the substrate, the dimension of the portion of the conductive layer of the wiring layer connected to the second portion of the through - electrode may be smaller than the dimension of the second portion of the through - electrode.

[0022] In a through - electrode substrate according to an embodiment of the present disclosure, the conductive layer may include an electrode portion that overlaps the second portion of the through - electrode and has a contour surrounded by the second portion when viewed along the normal direction of the first surface of the substrate.

[0023] In a through - electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a plurality of the electrode portions.

[0024] In a through - electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a lead - wire portion that intersects the contour of the second portion of the through - electrode when viewed along the normal direction of the first surface of the substrate.

[0025] In a through - electrode substrate according to an embodiment of the present disclosure, the conductive layer may include a plurality of the lead - wire portions.

[0026] In a through - electrode substrate according to an embodiment of the present disclosure, the wiring layer may further have an insulating layer containing an organic material and a stress - relaxation layer containing an inorganic material.

[0027] In a through-electrode substrate according to an embodiment of the present disclosure, the wiring layer includes a first wiring layer including the conductive layer and the insulating layer located on the first surface of the substrate, and a second wiring layer including the conductive layer and the insulating layer located on the first wiring layer. The stress relaxation layer may be located at least between the first surface of the substrate and the insulating layer of the first wiring layer, or between the insulating layer of the first wiring layer and the insulating layer of the second wiring layer.

[0028] An embodiment of the present disclosure includes a through-electrode substrate and an element mounted on the through-electrode substrate. The through-electrode substrate includes a substrate provided with a through-hole penetrating from a first surface to a second surface located on the opposite side of the first surface, and a through-electrode provided inside the through-hole of the substrate. The through-electrode has a first portion extending along the side wall of the through-hole and a second portion connected to the first portion and extending in the plane direction of the first surface so as to contact the side wall of the through-hole on the first surface side of the substrate. There is a hollow portion between the surfaces of the first portions facing each other inside the through-hole. The through-electrode substrate further includes an electrode portion located on the second portion of the through-electrode. The element is a mounting substrate having a terminal connected to the electrode portion.

[0029] According to the through-electrode substrate according to the embodiment of the present disclosure, an element can be arranged in a region of the substrate where the through-hole is provided.

Brief Description of the Drawings

[0030]

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Mode for Carrying Out the Invention

[0031] Hereinafter, the configuration of the through - electrode substrate and its manufacturing method according to the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments shown below are examples of the embodiments of the present disclosure, and the present disclosure is not construed as being limited to these embodiments. Also, in this specification, terms such as "substrate", "base material", "sheet", and "film" are not distinguished from each other based only on the difference in name. For example, "substrate" and "base material" are concepts that include members that can be called sheets or films. Further, with regard to terms used in this specification that specify shapes, geometric conditions, and their degrees, such as terms like "parallel" and "orthogonal", and values of lengths and angles, etc., they are not bound by strict meanings and are interpreted to include ranges where similar functions can be expected. Also, in the drawings referred to in this embodiment, the same parts or parts having the same function are denoted by the same reference numerals or similar reference numerals, and repeated explanations thereof may be omitted. Also, the dimensional ratios in the drawings may differ from the actual ratios for convenience of explanation, or a part of the configuration may be omitted from the drawings.

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to FIGS. 1 to 15.

[0033] Through-hole electrode substrate First, with reference to FIGS. 1 and 2, the through - electrode substrate 10 according to this embodiment will be described. FIG. 1 is a plan view showing the through - electrode substrate 10. FIG. 2 is a cross - sectional view of the through - electrode substrate 10 of FIG. 1 cut along the dashed - dotted line and viewed from the II - II direction.

[0034] The through - electrode substrate 10 includes a substrate 12, a plurality of through - holes 20 provided in the substrate 12, and through - electrodes 22 provided inside the through - holes 20. Hereinafter, each component of the through - electrode substrate 10 will be described.

[0035] (Substrate) The substrate 12 includes a first surface 13 and a second surface 14 located on the opposite side of the first surface 13. The substrate 12 is composed of a material having a certain insulating property. For example, the substrate 12 may be a glass substrate, a quartz substrate, a sapphire substrate, a resin substrate, a silicon substrate, a silicon carbide substrate, an alumina (Al2O3) substrate, an aluminum nitride (AlN) substrate, a zirconia oxide (ZrO2) substrate, etc., or a laminate of these substrates. The substrate 12 may also include a substrate composed of a conductive material such as an aluminum substrate or a stainless steel substrate.

[0036] The thickness of the substrate 12 is not particularly limited. For example, it is preferable to use a substrate 12 having a thickness of 100 μm or more and 800 μm or less. More preferably, the substrate 12 has a thickness of 200 μm or more and 600 μm or less. By setting the thickness of the substrate 12 to 100 μm or more, it is possible to suppress an increase in the deflection of the substrate 12. Therefore, it is possible to prevent the handling of the substrate 12 from becoming difficult in the manufacturing process, or the substrate 12 from warping due to internal stress of a thin film or the like formed on the substrate 12. Further, by setting the thickness of the substrate 12 to 800 μm or less, it is possible to suppress an increase in the manufacturing cost of the through-electrode substrate 10 due to an increase in the time required for the process of forming the through-holes 20 in the substrate 12.

[0037] (Through-hole) The through-hole 20 is provided in the substrate 12 so as to extend from the first surface 13 to the second surface 14 of the substrate 12. The dimension S1 of the through-hole 20 in the plane direction D1 of the first surface 13 is within a range of, for example, 20 μm or more and 150 μm or less at each position in the thickness direction of the substrate 12. Also, the interval P between two adjacent through-holes 20 in the plane direction D1, that is, the array pitch of the through-holes 20, is within a range of, for example, 40 μm or more and 300 μm or less. Note that the dimension S1 of the through-hole in the plane direction D1 of the first surface 13 is the maximum value of the opening width of the through-hole 20 when the through-hole 20 is cut by an arbitrary plane parallel to the first surface 13. Also, the plane direction D1 is a direction parallel to the first surface 13. In FIGS. 1 and 2, the symbol S11 represents the dimension of the through-hole 20 on the first surface 13 of the substrate 12. Also, in FIG. 2, the symbol S11 represents the dimension of the through-hole 20 on the second surface 14 of the substrate 12.

[0038] (Through electrode) The through electrode 22 is a conductive member provided inside the through-hole 20. As shown in FIG. 2, the through electrode 22 has at least a first portion 23 and a second portion 24. The first portion 23 is a portion that extends along the side wall 21 of the through-hole 20 so as to reach from the first surface 13 side to the second surface 14 side. The second portion 24 is a portion that is connected to the first portion 23 at the end of the first portion 23 on the first surface 13 side and extends in the plane direction D1 of the first surface 13 so as to contact the side wall 21 of the through-hole 20 on the first surface 13 side.

[0039] As shown in FIG. 2, the through electrode 22 may further have a third portion 25. The third portion 25 is a portion that is connected to the first portion 23 at the end of the first portion 23 on the second surface 14 side and is provided on the second surface 14.

[0040] FIG. 3 is a cross-sectional view showing an enlarged view of the through electrode 22 of the through electrode substrate 10 of FIG. 2. The second portion 24 of the through electrode 22 is preferably located on the same plane as the first surface 13 of the substrate 12. Here, "on the same plane" means that the difference ΔH between the position of the first surface 13 and the position of the outer surface 24a of the second portion 24 in the normal direction of the first surface 13 of the substrate 12 is 1 μm or less. The difference ΔH can be measured using a reflection type confocal laser microscope or a stylus type step gauge. In FIG. 3, an example is shown in which the outer surface 24a of the second portion 24 protrudes outward from the first surface 13, but the present invention is not limited thereto. Although not shown, as long as the difference ΔH is 1 μm or less, the outer surface 24a of the second portion 24 may be recessed inward from the first surface 13.

[0041] As long as the through electrode 22 has conductivity, the method for forming the through electrode 22 is not particularly limited. For example, the through electrode 22 may be formed by a physical film formation method such as a vapor deposition method or a sputtering method, or may be formed by a chemical film formation method or a plating method. Further, the through electrode 22 may be composed of a single layer having conductivity, or may include a plurality of layers having conductivity. Here, as shown in FIG. 3, an example in which the through electrode 22 includes a first layer 22a and a second layer 22b having conductivity will be described.

[0042] The first layer 22a is a so-called seed layer, and is a conductive layer that serves as a base for growing the second layer 22b by precipitating metal ions in a plating solution during an electrolytic plating process for forming the second layer 22b by plating. The material of the first layer 22a is preferably a conductive material that has high adhesion to the material of the substrate 12. For example, the material of the first layer 22a may be titanium, molybdenum, tungsten, tantalum, nickel, chromium, aluminum, compounds thereof, alloys thereof, or stacks thereof. The material of the first layer 22a may be a material that suppresses the diffusion of the second layer 22b into the substrate 12. For example, when the second layer 22b contains copper, the material of the first layer 22a may be titanium nitride, molybdenum nitride, tantalum nitride, or stacks thereof. The material of the first layer 22a may be the same as that of the second layer 22b. For example, when the second layer 22b contains copper, the first layer 22a may also contain copper. When the first layer 22a contains copper, a layer of a metal material having high adhesion to the substrate 12, such as titanium or titanium nitride, may be provided between the substrate 12 and the first layer 22a in order to improve adhesion between the substrate 12 and the first layer 22a. Furthermore, when the first layer 22a has sufficient thickness and conductivity, the second layer 22b may not be provided, and the first layer 22a may constitute the through electrode 22.

[0043] When the second layer 22b is provided on the first layer 22a, the thickness of the first layer 22a is, for example, 0.2 μm or less. When the second layer 22b is not provided, the thickness of the first layer 22a is, for example, 1 μm or more and 10 μm or less.

[0044] The second layer 22b is a conductive layer provided on the first layer 22a to enhance the conductivity of the through electrode 22. As the material of the second layer 22b, a conductive material having preferably high adhesion to the first layer 22a and high conductivity is used. For example, as the material of the second layer 22b, metals such as copper, gold, silver, platinum, rhodium, tin, aluminum, nickel, chromium, alloys using these, or those obtained by laminating these can be used. The thickness of the second layer 22b is, for example, in the range of 1 μm or more and 10 μm or less.

[0045] The thickness of the second layer 22b is determined according to the conductivity required for the through electrode 22. For example, when the through electrode 22 is a member for conducting a power line or a ground line, the second layer 22b having a sufficient thickness is used. Also, when the through electrode 22 is a member for conducting a weak electrical signal, the second layer 22b having a small thickness may be used. Or, only the first layer 22a may be provided in the through hole 20 without providing the second layer 22b to form the through electrode 22.

[0046] The through electrode 22 is configured such that a hollow portion is formed inside the through hole 20. The hollow portion is a region inside the through hole 20 where no solid such as the first layer 22a or the second layer 22b exists. In other words, as shown in FIG. 3, the hollow portion 26 is a region between the surfaces 23a of the first portions 23 facing each other inside the through hole 20 among the regions inside the through hole 20. The surface 23a is a surface located on the side opposite to the side of the side wall of the through hole 20 among the surfaces of the first portion 23. The dimension S5 of the hollow portion 26 in the plane direction D1 of the first plane 13 is, for example, 20% or more and 90% or less of the dimension S1 measured at the same position in the thickness direction of the substrate 12. By forming the through electrode 22 such that the hollow portion 26 is formed inside the through hole 20, the time required for forming the through electrode 22 can be shortened compared to the case where the inside of the through hole 20 is completely filled with the through electrode 22. Although not shown in the figures, a material having insulating properties such as resin may be provided in the hollow portion 26. This can suppress the intrusion of processing liquids such as developing solutions and cleaning solutions into the hollow portion 26 during the manufacturing process of the through-electrode substrate 10.

[0047] As shown in FIG. 2, preferably, the dimension S1 of the through-hole 20 in the surface direction D1 of the first surface 13 of the substrate 12 increases as it goes from the first surface 13 toward the second surface 14. In other words, the through-hole 20 has a tapered shape that becomes narrower as it goes toward the first surface 13. This can suppress the second portion 24 from being pulled and moving toward the first surface 13 side when peeling the sealing layer 17 described later from the second portion 24 of the through-electrode 22. Note that the through-hole 20 does not necessarily have a tapered shape over the entire area. As long as it is possible to suppress the through-electrode 22 from being pulled by the sealing layer 17 and moving, various shapes can be adopted as the shape of the through-hole 20.

[0048] The dimension S11 of the through-hole 20 on the first surface 13 of the substrate 12 is, for example, 10 μm or more and 100 μm or less. Also, the dimension S12 of the through-hole 20 on the second surface 14 side of the substrate 12 is, for example, 20 μm or more and 200 μm or less.

[0049] As shown in FIG. 1, preferably, the second portions 24 of the plurality of through-electrodes 22 are uniformly distributed on the first surface 13 of the substrate 12. For example, when the substrate 12 is virtually divided into N equal parts in the surface direction D1, the number of through-holes 20 formed in the N regions is within the range of the average value ±20%. Here, N is an appropriate integer, for example, 16.

[0050] (Wiring layer) As shown in FIG. 4, the through electrode substrate 10 may further include a wiring layer 30 provided on the first surface 13 side of the substrate 12. The wiring layer 30 has at least a conductive layer 31 connected to the second portion 24 of the through electrode 22. In the example shown in FIG. 4, the conductive layer 31 includes an electrode portion 33 provided on the second portion 24 of the through electrode 22. The electrode portion 33 is, for example, a bump connected to a terminal 52 of an element 51 described later. As the material of the conductive layer 31, a conductive material such as metal is used.

[0051] FIG. 5A is a plan view showing the through electrode substrate 10 of the example shown in FIG. 4. As shown in FIG. 5A, both the second portion 24 of the through electrode 22 and the electrode portion 33 have a circular shape in plan view. Further, the electrode portion 33 overlaps the second portion 24 of the through electrode 22 when viewed along the normal direction of the substrate 12. Further, the electrode portion 33 has a contour surrounded by the second portion 24 of the through electrode 22 when viewed along the normal direction of the substrate 12. For example, in the surface direction D1 of the first surface 13, the dimension S3 of the electrode portion 33 is smaller than the dimension S2 of the second portion 24.

[0052] FIGS. 5B and 5C are plan views showing other examples of the through electrode substrate 10, respectively. The shape of the electrode portion 33 in plan view is arbitrary. For example, as shown in FIG. 5B, the electrode portion 33 may have an elliptical shape in plan view. In this case, the dimension S3 of the elliptical electrode portion 33 in the major axis direction may be smaller than the dimension S2 of the second portion 24. Further, as shown in FIG. 5C, the electrode portion 33 may have a rectangular shape in plan view. In this case, the dimension S3 of one side of the rectangular electrode portion 33 may be smaller than the dimension S2 of the second portion 24. The shape of the second portion 24 of the through electrode 22 in plan view is also arbitrary.

[0053] Method for manufacturing a through-hole electrode substrate Hereinafter, an example of a method for manufacturing the through electrode substrate 10 will be described with reference to FIGS. 6 to 15.

[0054] (First resist layer formation step) First, prepare the substrate 12. Next, as shown in FIG. 6, provide a first resist layer 16 on the second surface 14 of the substrate 12. The first resist layer 16 is provided so as to cover a region of the second surface 14 of the substrate 12 where the through holes 20 are not formed. An opening 16a of the first resist layer 16 is located in a region of the second surface 14 of the substrate 12 where the through holes 20 are formed.

[0055] (Through hole forming step) Thereafter, the substrate 12 is processed from the second surface 14 side at the opening 16a of the first resist layer 16 to form a plurality of through holes 20 in the substrate 12 as shown in FIG. 7. As a method for processing the substrate 12, a dry etching method such as a reactive ion etching method or a deep reactive ion etching method, or a wet etching method can be used. Subsequently, the first resist layer 16 is removed. In this way, the substrate 12 provided with the through holes 20 can be prepared.

[0056] Preferably, as shown in FIG. 7, the substrate 12 is processed so that the through holes 20 have a tapered shape that becomes narrower as it goes from the second surface 14 side to the first surface 13 side. For example, the through hole 20 has a dimension S12 of about 50 μm on the second surface 14 side and a dimension S11 of about 30 μm on the first surface 13 side.

[0057] When the substrate 12 contains glass, as an etching solution for wet etching the substrate 12, hydrogen fluoride (HF), a mixed solution of ammonium fluoride (NH4F) and hydrogen fluoride, so-called buffered hydrofluoric acid, etc. can be used. When the substrate 12 contains silicon, as an etching solution for wet etching the substrate 12, potassium hydroxide (KH), tetramethylammonium hydroxide (TMAH), ethylenediamine pyrocatechol (EDP), hydrazine hydrate (N2H4·H2O), etc. can be used.

[0058] As the dry etching method, a dry etching RIE (Reactive Ion Etching) method using plasma, a DRIE (Deep Reactive Ion EtchingRIE) method using a Bosch process, a sandblasting method, etc. can be used.

[0059] Note that a through hole 20 may be formed in the substrate 12 by irradiating the substrate 12 with a laser. In this case, the first resist layer 16 may not be provided. As the laser for laser processing, an excimer laser, an Nd:YAG laser, a femtosecond laser, etc. can be used. When adopting an Nd:YAG laser, a fundamental wave with a wavelength of 1064 nm, a second harmonic with a wavelength of 532 nm, a third harmonic with a wavelength of 355 nm, etc. can be used.

[0060] Also, laser irradiation and wet etching can be appropriately combined. Specifically, first, a modified layer is formed in the region of the substrate 12 where the through hole 20 is to be formed by laser irradiation. Subsequently, the substrate 12 is immersed in hydrogen fluoride or the like to etch the modified layer. Thereby, the through hole 20 can be formed in the substrate 12.

[0061] Note that in FIGS. 6 and 7, an example of forming the through hole 20 in the substrate 12 by processing the substrate 12 from the second surface 14 side is shown, but the present invention is not limited thereto. For example, the substrate 12 may be processed from the first surface 13 side to form the through hole 20 in the substrate 12. Also, the substrate 12 may be processed from both the first surface 13 side and the second surface 14 side to form the through hole 20 in the substrate 12.

[0062] (Sealing layer formation step) Next, as shown in FIG. 8, a sealing layer 17 that closes the through hole 20 is provided on the first surface 13 of the substrate 12. The sealing layer 17 is a layer that serves as a base when forming the second portion 24 of the above-described through electrode 22 inside the through hole 20. The sealing layer 17 includes, for example, a base material layer containing a resin such as polyethylene terephthalate, and an adhesive layer laminated on the base material layer and attached to the first surface 13 of the substrate 12. The sealing layer 17 is, for example, a dicing tape.

[0063] Preferably, the adhesive layer of the sealing layer 17 contains a photocurable resin that cures when irradiated with light such as ultraviolet light. In this case, after forming the second portion 24 of the through electrode 22 on the sealing layer 17, by irradiating the sealing layer 17 with light such as ultraviolet light, the adhesive layer of the sealing layer 17 can be cured and the sealing layer 17 can be easily peeled off from the first surface 13 of the substrate 12.

[0064] (Electrode formation step) Next, an electrode formation step of forming a through electrode 22 inside the through hole 20 is performed. In the electrode formation step, first, as shown in FIG. 9, a first layer 22a is formed on the second surface 14 of the substrate 12, the side wall 21 of the through hole 20, and the portion of the sealing layer 17 that closes the through hole 20 from the second surface 14 side of the substrate 12. As a method for forming the first layer 22a, for example, a physical film formation method such as vapor deposition or sputtering, or a chemical film formation method can be used.

[0065] Subsequently, as shown in FIG. 10, a second resist layer 18 is partially formed on the first layer 22a on the second surface 14 of the substrate 12. Specifically, the second resist layer 18 is formed so that the region of the second surface 14 where the third portion 25 of the through electrode 22 is not provided is covered by the second resist layer 18.

[0066] Subsequently, as shown in FIG. 11, a second layer 22b is formed on the first layer 22a by electrolytic plating. Specifically, a plating solution is supplied from the second surface 14 side of the substrate 12, and an electric current is applied to the first layer 22a. As a result, the first layer 22a and the second layer 22b that spread along the sealing layer 17 can be formed on the side wall 21, on the sealing layer 17, and on the second surface 14. Among the first layer 22a and the second layer 22b, the portion extending along the side wall 21 becomes the first portion 23 of the through electrode 22, the portion spreading along the sealing layer 17 becomes the second portion 24 of the through electrode 22, and the portion spreading along the second surface 14 becomes the third portion 25. Preferably, as shown in FIG. 12, electrolytic plating is continued until the thickness T2 of the first layer 22a and the second layer 22b formed on the sealing layer 17 becomes larger than the thickness T1 of the first layer 22a and the second layer 22b formed on the side wall 21 of the through hole 20. For example, the thickness T2 is at least 1 μm larger than the thickness T1.

[0067] Subsequently, as shown in FIG. 13, the second resist layer 18 is removed. Next, as shown in FIG. 14, the first layer 22a covered by the second resist layer 18 is removed. Then, as shown in FIG. 15, the sealing layer 17 is removed. For example, first, the sealing layer 17 is irradiated with ultraviolet rays to reduce the adhesive force of the adhesive layer of the sealing layer 17. Next, the sealing layer 17 is peeled off from the substrate 12. In this way, the through electrode 22 including the first layer 22a and the second layer 22b can be formed. The through electrode 22 has a first portion 23 extending along the side wall 21 of the through hole 20, a second portion 24 connected to the first portion 23 and spreading in the surface direction D1 of the first surface 13 so as to contact the side wall 21 of the through hole 20 on the first surface 13 side of the substrate 12, and a third portion 25 connected to the first portion 23 and provided on the second surface 14. In the above description, an example in which the first portion 23, the second portion 24, and the third portion 25 of the through electrode 22 are formed simultaneously has been shown, but the present invention is not limited to this. For example, although not shown in the drawings, the second portion 24, the first portion 23, and the third portion 25 may be formed in this order. Alternatively, after forming the second portion 24, the first portion 23 and the third portion 25 may be formed simultaneously. In this case, a step of removing the sealing layer 17 may be performed between the step of forming the second portion 24 and the step of forming the first portion 23. Further, after forming the second portion 24 and the first portion 23 simultaneously, the third portion 25 may be formed.

[0068] Hereinafter, the advantages of the manufacturing method of the above-described through electrode substrate 10 according to the present embodiment will be described.

[0069] According to the present embodiment, the through electrode 22 is formed inside the through hole 20 in a state where the through hole 20 is closed with the sealing layer 17. Therefore, even in the case of adopting a so-called conformal via in which a hollow portion exists inside the through hole 20, the second portion 24 of the through electrode 22 located on the same plane as the first surface 13 of the substrate 12 can be provided in a region overlapping the through hole 20. As a result, the through electrode 22 and the conductive layer 31 of the wiring layer 30 can be connected in a region overlapping the through hole 20. Therefore, since it is not necessary to secure a region for connection with the conductive layer 31 of the wiring layer 30 on the first surface 13 of the substrate 12, the interval P between two adjacent through holes 20 can be reduced. As a result, the distribution density of the through holes 20 of the through electrode substrate 10 can be increased. Further, by adopting a conformal via, the time required for the forming step of the through electrode 22 can be shortened as compared with the case of a field via.

[0070] Method for manufacturing a through-hole electrode substrate in a comparative form By the way, as a method of forming the through electrode 22 having the first portion 23 and the second portion 24, in addition to the method according to the above-described present embodiment, a method according to the following comparative form can be considered. Hereinafter, the manufacturing method of the through electrode substrate 10 according to the comparative form will be described with reference to FIGS. 16 to 18.

[0071] First, as shown in FIG. 16, a conductive layer 71 is provided on the first surface 13 of the substrate 12. Specifically, the conductive layer 71 is provided so as to cover the through holes 20 to be formed later in the substrate 12. Next, as shown in FIG. 17, through holes 20 are formed in the substrate 12 from the second surface 14 side. For example, the substrate 12 is processed by dry etching, wet etching, laser irradiation, etc. to form the through holes 20. Then, as shown in FIG. 18, through electrodes 22 connected to the conductive layer 71 are formed inside the through holes 20.

[0072] In the comparative form, as described above, after the conductive layer 71 is provided on the first surface 13 side of the substrate 12, the through holes 20 are formed from the second surface 14 side of the substrate 12. In this case, when the processing of the substrate 12 proceeds beyond the first surface 13 of the substrate 12 and reaches the conductive layer 71, as shown in FIG. 17, depressions 71a are formed in the conductive layer 71. For this reason, in the comparative form, it is necessary to make the thickness of the conductive layer 71 sufficiently large so that the depressions 71a do not penetrate the conductive layer 71. As a result, the thickness of the entire through electrode substrate 10 increases. Further, when the thickness of the conductive layer 71 increases, the through electrode substrate 10 is likely to warp due to the residual stress inside the conductive layer 71. Also, when the through holes 20 are formed by dry etching or wet etching, if the etching gas or etching liquid remains in the depressions 71a of the conductive layer 71, the conductive layer 71 is likely to corrode. As a result, the reliability of the connection between the conductive layer 71 and the through electrodes 22 decreases.

[0073] Also, in the step of processing the substrate 12 from the second surface 14 side to form the through holes 20 in the substrate 12, the position and dimensions of the through holes 20 may deviate from the design due to manufacturing tolerances. Even when the position and dimensions of the through holes 20 deviate from the design, in order to ensure that the through holes 20 are covered by the conductive layer 71, it is necessary to make the dimensions of the conductive layer 71 in the plane direction of the first surface 13 of the substrate 12 larger than the dimensions of the through holes 20 and the second portion 24 of the through electrodes 22 by at least the amount of the manufacturing tolerances. Therefore, the conductive layer 71 extends to a portion that does not overlap with the through holes 20. In this case, the distance between two adjacent through holes 20 is set in consideration of the portion of the conductive layer 71 that extends to a portion that does not overlap with the through holes 20. For this reason, in a comparative form, it is not easy to increase the distribution density of the through holes 20 in the through electrode substrate 10.

[0074] On the other hand, in the present embodiment, after forming the second portion 24 of the through electrode 22, the conductive layer 31 of the wiring layer 30 is formed on the second portion 24. Further, since the second portion 24 is formed on the surface of the sealing layer 17, the outer surface 24a of the second portion 24 has the same flatness as the surface of the sealing layer 17. Therefore, even when the thickness of the conductive layer 31 is small, the reliability of the connection between the conductive layer 31 and the second portion 24 of the through electrode 22 can be ensured. Accordingly, the overall thickness of the through electrode substrate 10 can be reduced. Further, it is possible to suppress warping of the through electrode substrate 10 due to residual stress inside the conductive layer 31.

[0075] Also, according to the present embodiment, since the conductive layer 31 of the wiring layer 30 is formed on the outer surface 24a of the second portion 24, the dimension S3 of the conductive layer 31 in the plane direction of the first surface 13 of the substrate 12 can be made smaller than the dimension of the second portion 24. For this reason, the distance P between two adjacent through holes 20 can be reduced. As a result, the distribution density of the through holes 20 in the through electrode substrate 10 can be increased.

[0076] Mounting substrate Hereinafter, an example of the use of the through - electrode substrate 10 according to this embodiment will be described. Here, an example of configuring the mounting substrate 50 by mounting the element 51 on the through - electrode substrate 10 will be described.

[0077] FIG. 19 is a cross - sectional view showing the mounting substrate 50, and FIG. 20 is a plan view showing the mounting substrate 50 in the example shown in FIG. 19. The mounting substrate 50 includes a through - electrode substrate 10 and an element 51 mounted on the through - electrode substrate 10 on the first - surface 13 side of the substrate 12. The element 51 is an LSI chip such as a logic IC or a memory IC. Also, the element 51 may be a MEMS (Micro Electro Mechanical Systems) chip. A MEMS chip is an electronic device in which mechanical - element parts, sensors, actuators, electronic circuits, etc. are integrated on one substrate. As shown in FIG. 19, the element 51 has a terminal 52 connected to the electrode portion 33 of the wiring layer 30 of the through - electrode substrate 10.

[0078] As shown in FIG. 21, the mounting substrate 50 may further include a circuit board 55 connected to the through - electrode substrate 10 on the second - surface 14 side of the substrate 12. In this case, the through - electrode substrate 10 of the mounting substrate 50 further has an electrode portion 38 provided in the third portion 25 of the through - electrode 22. Also, the circuit board 55 has a base material 56 and an electrode portion 57 provided on the base material 56 and connected to the electrode portion 38 of the through - electrode substrate 10.

[0079] The base material 56 of the circuit board 55 includes an organic material such as polyimide, epoxy, or acrylic, for example. In this case, when some heat treatment is applied to the base material 56, internal stress may be generated in the base material 56 due to thermal expansion. According to this embodiment, since the substrate 12 of the through - electrode substrate 10 includes a material having high rigidity such as glass or silicon, it is possible to suppress the influence of the internal stress of the base material 56 from reaching the element 51 and the wiring layer 30 mounted on the first - surface 13 side of the through - electrode substrate 10. For this reason, the reliability of the connection between the through - electrode substrate 10 and the element 51 can be ensured.

[0080] It should be noted that various modifications can be made to the above-described embodiments. Hereinafter, with reference to the drawings as necessary, modification examples will be described. In the following description and the drawings used in the following description, for parts that can be configured in the same manner as in the above-described embodiments, the same reference numerals as those used for the corresponding parts in the above-described embodiments will be used, and redundant descriptions will be omitted. Further, when it is clear that the operational effects obtained in the above-described embodiments can also be obtained in the modification examples, the description thereof may be omitted.

[0081] (First Modification Example) FIG. 22 is a cross-sectional view showing a through-electrode substrate 10 according to the first modification example. Further, FIG. 23 is a plan view showing the through-electrode substrate 10 according to the first modification example as viewed from the first surface 13 side of the substrate 12. As shown in FIGS. 22 and 23, the conductive layer 31 of the wiring layer 30 may include a plurality of electrode portions 33 provided on the second portion 24 of the through-electrode 22. Since the conductive layer 31 of the wiring layer 30 is formed after the second portion 24 of the through-electrode 22 of the through-electrode substrate 10 is formed, it becomes possible to divide the electrode portions 33 of the conductive layer 31 on the second portion 24 into a plurality.

[0082] (Second Modification Example) FIG. 24 is a cross-sectional view showing a through-electrode substrate 10 according to the second modification example. Further, FIG. 25 is a plan view showing the through-electrode substrate 10 according to the second modification example as viewed from the first surface 13 side of the substrate 12. As shown in FIGS. 24 and 25, the conductive layer 31 of the wiring layer 30 includes a conductor portion 34 that intersects the contour of the second portion 24 of the through-electrode 22 when viewed along the normal direction of the first surface 13 of the substrate 12. As shown in FIG. 25, in the surface direction D1 of the first surface 13, the dimension S4 of the conductor portion 34 located on the second portion 24 is smaller than the dimension S2 of the second portion 24. Note that the dimension S4 of the conductor portion 34 is measured in a direction orthogonal to the direction D2 in which the conductor portion 34 located on the second portion 24 extends.

[0083] As described above, the second portion 24 of the through electrode 22 of the through electrode substrate 10 is located on the same plane as the first surface 13 of the substrate 12. In other words, there is almost no step between the outer surface 24a of the second portion 24 and the first surface 13 of the substrate 12. Therefore, even when the conductive wire portion 34 extends across the second portion 24 and the first surface 13 as in this modified example, it is possible to suppress stress concentration on a part of the conductive wire portion 34 due to the step, and it is possible to suppress disconnection of the conductive wire portion 34. Therefore, the reliability of the conductive wire portion 34 can be ensured. Further, since the thickness of the conductive wire portion 34 can be reduced, the thickness of the entire through electrode substrate 10 can be reduced.

[0084] (Third Modified Example) FIG. 26 is a cross-sectional view showing a through electrode substrate 10 according to the third modified example. As shown in FIG. 26, the wiring layer 30 provided on the first surface 13 side of the substrate 12 may further include an insulating layer 36 in addition to the conductive layer 31. The insulating layer 36 contains an insulating organic material, for example, contains polyimide. In this case, the conductive layer 31 includes, for example, an electrode portion 33 that functions as a through electrode penetrating the insulating layer 36, and a conductive wire portion 34 covered by the insulating layer 36.

[0085] As shown in FIG. 26, the wiring layer 30 may have a plurality of layers including the conductive layer 31 and the insulating layer 36. For example, the wiring layer 30 has a first wiring layer 41 including a conductive layer 31 and an insulating layer 36 provided on the first surface 13 of the substrate 12, and a second wiring layer 42 including a conductive layer 31 and an insulating layer 36 provided on the first wiring layer 41.

[0086] As shown in FIG. 26, the layer located on the outermost surface of the wiring layer 30, here the second wiring layer 42, may further include a coating layer 35 provided on the electrode portion 33. The coating layer 35 contains a conductive material having corrosion resistance, for example, contains gold. Further, the coating layer 35 may include a plurality of layers. For example, the coating layer 35 may include a gold layer located on the outermost surface and a nickel layer disposed between the gold layer and the electrode portion 33.

[0087] As shown in FIG. 27, an element 51 may be mounted on the wiring layer 30 shown in FIG. 26 to form a mounting substrate 50. The above-described coating layer 35 functions as a pad connected to the terminal 52 of the element 51. Although not shown, the coating layer 35 may not be provided. Even in this case, the mounting substrate 50 can be configured by connecting the terminal 52 of the element 51 to the electrode portion 33 of the second wiring layer 42 of the wiring layer 30.

[0088] Hereinafter, with reference to FIGS. 28 to 32, an example of a method for manufacturing the wiring layer 30 according to this modification will be described.

[0089] First, the through-electrode substrate 10 according to the above-described present embodiment is prepared. Next, as shown in FIG. 28, an electrode portion 33 is formed on the second portion 24 of the through electrode 22 of the through electrode substrate 10. Also, a conductor portion 34 is formed on the first surface 13 of the substrate 12 of the through electrode substrate 10.

[0090] As a method for forming the electrode portion 33 and the conductor portion 34, for example, the same method as the method for forming the through electrode 22 of the through electrode substrate 10 can be adopted. For example, formation of a first layer functioning as a seed layer, formation of a resist layer, formation of a second layer by electrolytic plating treatment, removal of the resist layer, and removal of the first layer are sequentially performed. In this case, the electrode portion 33 and the conductor portion 34 each include a first layer having conductivity and functioning as a seed layer, and a second layer having conductivity and formed on the first layer by an electrolytic plating process. A layer of a metal material having high adhesion to the through electrode 22 or the substrate 12, such as titanium or titanium nitride, may be provided between the first layer functioning as a seed layer and the through electrode 22 or the substrate 12.

[0091] In the through-electrode substrate 10 according to the above-described present embodiment, there is almost no step between the outer surface 24a of the second portion 24 and the first surface 13 of the substrate 12. Therefore, even when the thickness of the conductive layer 31 provided on the outer surface 24a of the second portion 24 and the first surface 13 of the substrate 12, such as the above-described first layer of the electrode portion 33 and the conductor portion 34, is small, it is possible to suppress the conductive layer 31 from being disconnected due to the step.

[0092] Next, a layer of an organic material having photosensitivity and insulation is provided on the first surface 13 of the substrate 12 so as to cover the electrode portion 33 and the conductive wire portion 34. Then, the layer of the organic material is exposed and developed so that the portion of the layer of the organic material on the electrode portion 33 is removed. As a result, as shown in FIG. 29, an insulating layer 36 having an opening 36a for exposing the electrode portion 33 on the through electrode 22 and covering the conductive wire portion 34 can be formed.

[0093] Next, as shown in FIG. 30, another electrode portion 33 is further formed on the electrode portion 33, and a conductive wire portion 34 is formed on the insulating layer 36. For example, similar to the case of forming the electrode portion 33 and the conductive wire portion 34 on the substrate 12, formation of a first layer functioning as a seed layer, formation of a resist layer, formation of a second layer by electrolytic plating treatment, removal of the resist layer, and removal of the first layer are sequentially performed.

[0094] Next, as shown in FIG. 31, an insulating layer 36 that exposes the electrode portion 33 on the through electrode 22 and covers the conductive wire portion 34 is formed. Subsequently, as shown in FIG. 32, another electrode portion 33 is further formed on the already provided electrode portion 33 so that the electrode portion 33 protrudes from the surface of the insulating layer 36. In this way, a wiring layer 30 including the electrode portion 33 penetrating the insulating layer 36 and the conductive wire portion 34 covered by the insulating layer 36 can be formed.

[0095] (Fourth Modified Example) FIG. 33 is a cross-sectional view showing a through electrode substrate 10 according to the fourth modified example. As shown in FIG. 33, a plurality of electrode portions 33 penetrating the insulating layer 36 of the wiring layer 30 may be connected to the second portion 24 of one through electrode 22. Since the conductive layer 31 of the wiring layer 30 is formed after the second portion 24 of the through electrode 22 of the through electrode substrate 10 is formed, it becomes possible to divide the electrode portion 33 of the conductive layer 31 on the second portion 24 into a plurality of parts.

[0096] (Fifth Modified Example) FIG. 34 is a cross-sectional view showing a through electrode substrate 10 according to a fifth modification. As shown in FIG. 34, the wiring layer 30 provided on the first surface 13 side of the substrate 12 may further include a stress relaxation layer 37 disposed between the substrate 12 and the insulating layer 36. The stress relaxation layer 37 is a layer for relaxing the internal stress of the insulating layer 36. The stress relaxation layer 37 includes an inorganic material having insulating properties. For example, the stress relaxation layer 37 includes a nitrogen compound such as silicon oxide or nitrogen oxide.

[0097] Hereinafter, the advantages of providing the stress relaxation layer 37 will be described. The insulating layer 36 of the wiring layer 30 contains an organic material. When such an insulating layer 36 is provided on the substrate 12 containing glass, internal stress that acts to pull the substrate 12 is likely to occur in the insulating layer 36. Hereinafter, such internal stress is referred to as tensile stress. When the tensile stress increases, it is conceivable that the substrate 12 will warp.

[0098] On the other hand, internal stress that acts to compress the substrate 12 is likely to occur in the stress relaxation layer 37 containing an inorganic material. Hereinafter, such internal stress is referred to as compressive stress. According to this modification, by providing the stress relaxation layer 37 between the substrate 12 and the insulating layer 36, the tensile stress of the insulating layer 36 can be relaxed. Therefore, it is possible to suppress warping of the substrate 12. In FIG. 34, an example of providing the stress relaxation layer 37 between the substrate 12 and the insulating layer 36 of the first wiring layer 41 is shown. However, the specific position of the stress relaxation layer 37 is not particularly limited. For example, the stress relaxation layer 37 may be located between the insulating layer 36 of the first wiring layer 41 and the insulating layer 36 of the second wiring layer 42. In this case, a further stress relaxation layer 37 may also exist between the substrate 12 and the insulating layer 36 of the first wiring layer 41, or the stress relaxation layer 37 may not exist between the substrate 12 and the insulating layer 36 of the first wiring layer 41.

[0099] The thickness of the insulating layer 36 and the thickness of the stress relaxation layer 37 are set so that their stresses can appropriately cancel each other out. For example, when the insulating layer 36 contains an insulating organic material such as polyimide, epoxy, or acrylic and has a thickness of 5 μm or more and 20 μm or less, the stress relaxation layer 37 contains an insulating material such as a silicon compound and has a thickness of 1 μm or more and 5 μm or less. Examples of the silicon compound include SiO2, SiN, SiOC, SiC, SiOF, SiON, SiCN, etc.

[0100] (Sixth Modified Example) In the above-described embodiment, an example in which the side wall 21 of the through hole 20 has a linear shape in the cross-sectional view has been shown. However, as long as the through electrode 22 including the first portion 23 and the second portion 24 can be provided, the shape of the through hole 20 is not particularly limited. For example, as shown in FIG. 35, the side wall 21 of the through hole 20 may have a curved shape in the cross-sectional view.

[0101] (Seventh Modified Example) In the above-described embodiment, an example in which the through electrode 22 has a third portion 25 provided on the second surface 14 in addition to the first portion 23 that extends along the side wall 21 of the through hole 20 and the second portion 24 that extends in the plane direction D1 of the first surface 13 so as to be in contact with the side wall 21 of the through hole 20 on the first surface 13 side has been shown. However, as shown in FIG. 36, the through electrode 22 only needs to have at least the first portion 23 and the second portion 24.

[0102] 〔Examples of Products on Which the Through-Electrode Substrate is Mounted〕 FIG. 39 is a diagram showing an example of a product on which the through-electrode substrate 10 according to the embodiment of the present disclosure can be mounted. The through-electrode substrate 10 according to the embodiment of the present disclosure can be used in various products. For example, it is mounted on a notebook personal computer 110, a tablet terminal 120, a mobile phone 130, a smartphone 140, a digital video camera 150, a digital camera 160, a digital clock 170, a server 180, etc.

Examples

[0103] Next, the present disclosure will be described more specifically with reference to examples. However, the present disclosure is not limited to the following description of the examples as long as the gist thereof is not exceeded.

[0104] (Example 1) First, based on the manufacturing method of the through - electrode substrate 10 according to the above - described embodiment of the present disclosure, the through - electrode substrate 10 shown in FIG. 40 was fabricated. The through - electrode substrate 10 includes a substrate 12 provided with through - holes 20, a through - electrode 22 provided inside the through - holes 20 and including a first portion 23, a second portion 24, and a third portion 25, and a wiring layer 30 provided on the first surface 13 side of the substrate 12 and including an electrode portion 33 connected to the second portion 24 of the through - electrode 22. The wiring layer 30 is provided on the first surface 13 side of the substrate 12, and includes an insulating layer 36 formed with an opening corresponding to the electrode portion 33, and a conductive wire portion 34 provided on the insulating layer 36 and connecting the electrode portions 33 on the second portions 24 of the through - electrodes 22 of two adjacent through - holes 20 through the opening of the insulating layer 36.

[0105] With a state where current was passed between the through - electrodes 22 of two adjacent through - holes 20, a temperature cycle test was performed for 1000 cycles. One cycle includes a step of raising the ambient temperature of the through - electrode substrate 10 from - 45°C to 125°C, a step of maintaining the ambient temperature at 125°C, a step of lowering the ambient temperature from 125°C to - 45°C, and a step of maintaining the ambient temperature at - 45°C. The required time for one cycle is 40 minutes.

[0106] After performing the temperature cycle test for 1000 cycles, it was inspected whether or not conduction failure occurred. As a result, it was confirmed that conduction failure did not occur at all inspection points.

[0107] (Comparative Example 1) First, based on the manufacturing method of the through - electrode substrate 70 according to the above - described comparison form, the through - electrode substrate 70 shown in FIG. 41 was fabricated. The through - electrode substrate 70 includes a substrate 12 provided with a through - hole 20, a through - electrode 22 provided inside the through - hole 20 and including a first portion 23, a second portion 24, and a third portion 25, and a wiring layer 80 provided on the first - surface 13 side of the substrate 12 and including a conductive layer 71 connected to the second portion 24 of the through - electrode 22. The wiring layer 80 is provided on the first - surface 13 side of the substrate 12, and includes an insulating layer 36 formed with an opening corresponding to the conductive layer 71, and a conductive - wire portion 34 provided on the insulating layer 36 and connecting the conductive layers 71 on the second portions 24 of the through - electrodes 22 of two adjacent through - holes 20 through the opening of the insulating layer 36.

[0108] In the same manner as in the case of the above - described Example 1, a temperature - cycle test was performed 1000 cycles. As a result, conduction failure occurred at 80% of the inspection locations. In Comparative Example 1, a depression 71a occurred in the conductive layer 71, and it is considered that the electrical connection between the conductive layer 71 and the second portion 24 of the through - electrode 22 became unstable due to the corrosion of the depression 71a, resulting in conduction failure.

Explanation of Reference Numerals

[0109] 10 Through - electrode substrate 12 Substrate 13 First surface 14 Second surface 16 First resist layer 16a Opening 17 Encapsulation layer 18 Second resist layer 20 Through - hole 21 Side wall 22 Through - electrode 22a First layer 22b Second layer 23 First portion 24 Second portion 25 Third portion 30 Wiring layer 31 Conductive layer 33 Electrode portion 34 Conductive - wire portion 35 Coating layer 36 Insulating layer 36a opening 37 stress relaxation layer 38 electrode portion 41 first wiring layer 42 second wiring layer 50 mounting substrate 51 element 52 terminal 55 circuit board 56 base material 57 electrode portion 70 through - electrode substrate 71 conductive layer

Claims

[Claim 1] a substrate including a first surface and a second surface located opposite to the first surface and having a through hole; a through electrode provided inside the through hole of the substrate, the through electrode has a first portion extending along a side wall of the through hole, and a second portion connected to the first portion, extending in a surface direction of the first surface so as to contact the side wall of the through hole on the first surface side of the substrate, and having a thickness larger than that of the first portion; A through hole electrode substrate, wherein a hollow portion exists between opposing surfaces of the first portion inside the through hole.

Images